| PATENT ASSIGNEE'S COUNTRY | Australia |
| UPDATE | 09.99 |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 14.09.99 |
| PATENT TITLE |
Destruction of halide containing organics and solvent purification |
| PATENT ABSTRACT |
A process for removal of halide from a halide containing organic compound in a solvent, a process for simultaneous removal of halide from a halide containing organic compound and reduction of an oxygen containing organic compound in a solvent, a process for removal of halide from a halide containing organic compound, a process for reduction of an oxygen containing organic compound in a solvent, a system for removal of halide from a halide containing organic compound in a solvent, a system for simultaneous removal of halide from a halide containing organic compound and the reduction of an oxygen containing organic compound in a solvent, and a system for reducing an oxygen containing organic compound in a solvent are disclosed. The process for simultaneous removal of halide from a halide containing organic compound and reduction of an oxygen containing organic compound in a solvent, includes exposing a solvent having a halide containing organic compound and an oxygen containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to a catalyst which is capable, in the presence of hydrogen, of (i) converting the halide in the halide containing organic compound to hydrohalic acid; and (ii) reducing the oxygen containing organic compound; at a pressure and at an elevated temperature and for a time sufficient (a) to convert the halide in the halide containing organic compound to hydrohalic acid; and (b) to reduce the oxygen containing organic compound; and neutralizing the hydrohalic acid formed in (a) with hydrogen halide scavenger. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | 28.08.95 |
| PATENT CT FILE DATE | 23.12.93 |
| PATENT CT NUMBER | This data is not available for free |
| PATENT CT PUB NUMBER | This data is not available for free |
| PATENT CT PUB DATE | 07.07.94 |
| PATENT REFERENCES CITED | This data is not available for free |
| PATENT CLAIMS |
We claim: 1. A process for removal of halide from a halide containing organic compound in a solvent of hydrocarbon or oil, the process comprising the steps of: exposing a solvent of hydrocarbon or oil having a halide containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to a catalyst which is capable, in the presence of hydrogen, of converting the halide in the halide containing organic compound to hydrohalic acid, at a pressure and at an elevated temperature and for a time sufficient to convert the halide in the halide containing organic compound to hydrohalic acid; and neutralizing the resulting hydrohalic acid with the hydrogen halide scavenger. 2. The process of claim 1 further comprising the step of: neutralizing any catalyst acid sites with the hydrogen halide scavenger. 3. The process of claim 1 further comprising the step of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 4. The process of claim 1 wherein at the pressure and the elevated temperature: the neutralizing of the resulting hydrohalic acid with hydrogen halide scavenger results in a neutralization product(s) that does not substantially precipitate on the catalyst, and wherein the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 5. The process of claim 1 wherein at the pressure and the elevated temperature: the neutralizing of the resulting hydrohalic acid with hydrogen halide scavenger results in a neutralization product(s) comprising a neutralization product(s) selected from the group consisting of vaporized ammonium halide and dissociated ammonia and gaseous hydrohalic acid, that does not substantially precipitate on the catalyst, and wherein the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 6. The process of claim 1, wherein said halide containing organic compound is a polychlorinated biphenyl. 7. A process for simultaneous removal of halide from a halide containing organic compound and reduction of an oxygen containing organic compound in a solvent of hydrocarbon or oil, the process comprising the steps of: exposing a solvent of hydrocarbon or oil having a halide containing organic compound and an oxygen containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to a catalyst which is capable, in the presence of hydrogen, of: i) converting the halide in the halide containing organic compound to hydrohalic acid; and ii) reducing the oxygen containing organic compound; at a pressure and at an elevated temperature and for a time sufficient: a) to convert the halide in the halide containing organic compound to hydrohalic acid; and b) to reduce the oxygen containing compound; and neutralizing the resulting hydrohalic acid formed in (a) with the hydrogen halide scavenger. 8. The process of claim 7 further comprising the step of: neutralizing any catalyst acid sites with the hydrogen halide scavenger. 9. The process of claim 7 further comprising the step of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 10. The process of claim 7 wherein at the pressure and the elevated temperature: the neutralizing of the resulting hydrohalic acid with hydrogen halide scavenger results in a neutralization product(s) that does not substantially precipitate on the catalyst, and wherein the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 11. The process of claim 7 wherein at the pressure and the elevated temperature: the neutralizing of the resulting hydrohalic acid formed with hydrogen halide scavenger results in a neutralization product(s) comprising a neutralization product(s) selected from the group consisting of vaporized ammonium halide and dissociated ammonia and gaseous hydrohalic acid, that does not substantially precipitate on the catalyst, and wherein the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 12. The process of claim 7, wherein said halide containing organic compound is a polychlorinated biphenyl. 13. A process for removal of a halide from a halide containing organic compound, the process comprising the steps of: dissolving the halide containing organic compound in a solvent of hydrocarbon or oil; exposing the solvent having a halide containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to a catalyst which is in the presence of hydrogen, of converting the halide in the halide containing organic compound to hydrohalic acid, at a pressure and at an elevated temperature and for a time sufficient to convert the halide in the halide containing organic compound to hydrohalic acid; and neutralizing the resulting hydrohalic acid with the hydrogen halide scavenger. 14. The process of claim 13 further comprising the step of: neutralizing any catalyst acid sites with the hydrogen halide scavenger. 15. The process of claim 13 further comprising the step of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 16. The process of claim 13 wherein at the pressure and the elevated temperature: the neutralizing of the resulting hydrohalic acid with hydrogen halide scavenger results in a neutralization product(s) that does not substantially precipitate on the catalyst, and wherein the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 17. The process of claim 13 wherein at the pressure and the elevated temperature: the neutralizing of the resulting hydrohalic acid with hydrogen halide scavenger results in a neutralization product(s) comprising a neutralization product(s) selected from the group consisting of vaporized ammonium halide and dissociated ammonia and gaseous hydrohalic acid, that does not substantially precipitate on the catalyst, and wherein the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 18. The process of claim 13, wherein said halide containing organic compound is a polychlorinated biphenyl. 19. A process for reduction of an oxygen containing organic compound in a solvent of hydrocarbon or oil, the process comprising the steps of: exposing a solvent of hydrocarbon or oil having an oxygen containing organic compound, in the presence of hydrogen and acid scavenger, to a catalyst which is capable, in the presence of hydrogen, of: i) reducing the oxygen containing organic compound; at a pressure and at an elevated temperature and for a time sufficient to reduce the oxygen containing organic compound; and neutralizing any acid in the exposed solvent and any catalyst acid sites with the acid scavenger. 20. The process of claim 19 further comprising the step of: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. 21. The process of claim 19, wherein said oxygen containing organic compound is a compound resulting from aging of transformer oil. 22. A process for removal of halide from a halide containing organic compound in a solvent of hydrocarbon or oil, the process comprising the steps of: exposing a halide containing organic compound in a solvent of hydrocarbon or oil, in the presence of hydrogen and a nitrogen containing compound, to a catalyst which is capable, in the presence of hydrogen, of converting the halide in the halide containing organic compound to hydrohalic acid, at a pressure and at an elevated temperature and for a time sufficient to convert the halide in the halide containing organic compound to hydrohalic acid; and neutralizing the resulting hydrohalic acid with the nitrogen containing compound at a pressure and at an elevated temperature to form a hydrohalic acid neutralization product that does not substantially precipitate on said catalyst. 23. The process of claim 22 further comprising the steps of adding a compound to said solvent, wherein said compound is transformed into a nitrogen containing compound under the conditions of said process. 24. The process of claim 22 further comprising the step of: neutralizing any catalyst acid sites with the nitrogen containing compound. 25. The process of claim 22 further comprising the step of: removing the exposed solvent from the catalyst; and separating non-solvent materials from the exposed solvent. 26. The process of claim 22 wherein said neutralizing of the hydrohalic acid formed with the nitrogen containing compound results in a neutralization product(s) comprising a neutralization product(s) selected from the group consisting of vaporized ammonium halide and dissociated ammonia and gaseous hydrohalic acid, and the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non-solvent materials from the exposed solvent. 27. The process of claim 22 wherein the pressure is in the range from about 0.1 MPa to about 50 MPa and the elevated temperature is in the range from about 200 to about 500.degree. C. 28. The process of claim 22 wherein the pressure is in the range from about 1 MPa to about 10 MPa and the elevated temperature is in the range of from about 275 to 375.degree. C. 29. The process of claim 22 wherein the solvent comprises transformer oil. 30. The process of claim 22 wherein the halide is chloride. 31. The process of claim 22 wherein the nitrogen containing compound comprises ammonia. 32. The process of claim 22 wherein the pressure is in the range of from about 1 MPa to about 10, MPa and the elevated temperature is in the range of from about 300 to about 375.degree. C., the solvent comprises transformer oil, the halide is chloride--and the nitrogen containing compound comprises ammonia. 33. The process of claim 22 wherein the pressure and elevated temperature are maintained at a level at which the neutralization product remains substantially in the gaseous phase or disassociated in the gaseous phase such that the catalyst remains substantially uncontaminated by the neutralization products. 34. The process of claim 22, wherein said halide containing organic compound is a polychlorinated biphenyl. 35. A process for simultaneous removal of halide from a halide containing organic compound and reduction of an oxygen containing organic compound in a solvent of hydrocarbon or oil, the process comprising the steps of: exposing a halide containing organic compound and an oxygen containing organic compound in a solvent of hydrocarbon or oil, in the presence of hydrogen and a nitrogen containing compound, to a catalyst which is capable, in the presence of hydrogen, of: (i) converting the halide in the halide containing organic compound to hydrohalic acid; and (ii) reducing the oxygen containing organic compound at a pressure and at an elevated temperature and for a time sufficient: (a) to convert the halide in the halide containing organic compound to hydrohalic acid; and (b) to reduce the oxygen containing organic compound and neutralizing the resulting hydrohalic acid formed in (a) with said nitrogen containing compound at a pressure and at an elevated temperature to form a hydrohalic acid neutralization product that does not substantially precipitate on said catalyst. 36. The process of claim 35 further comprising the step of adding a compound to said solvent, wherein said compound is transformed into a nitrogen compound under the conditions of said process. 37. The process of claim 35 further comprising the step of: neutralizing any catalyst acid sites with the nitrogen containing compound. 38. The process of claim 35 further comprising the step of: removing the exposed solvent from the catalyst; and separating non-solvent materials from the exposed solvent. 39. The process of claim 35 wherein said neutralizing of the hydrohalic acid formed with the nitrogen containing compound results in a neutralization product(s) comprising a neutralization product(s) selected from the group consisting of vaporized ammonium halide and dissociated ammonia and gaseous hydrohalic acid, and the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non-solvent materials from the exposed solvent. 40. The process of claim 35 wherein the pressure is in the range from about 0.5 MPa to about 50 MPa and the elevated temperature is in the range from about 200 to 500.degree. C. 41. The process of claim 35 wherein the pressure is in the range from about 1 MPa to about 10 MPa and the elevated temperature is in the range from about 275 to about 375.degree. C. 42. The process of claim 35 wherein the solvent comprises transformer oil. 43. The process of claim 35 wherein the halide is chloride. 44. The process of claim 35 wherein the nitrogen containing compound comprises ammonia. 45. The process claim 35 wherein the pressure is in the range of from about 1 MPa to about 10 MPa and the elevated temperature is in the range of from about 300 to about 375.degree. C., the solvent comprises transformer oil, the halide is chloride--and the nitrogen containing compound comprises ammonia. 46. The process of claim 35 wherein the pressure and elevated temperature are maintained at a level at which the neutralization product remains substantially in the gaseous phase or dissociated in the gaseous phase such that the catalyst remains substantially uncontaminated by the neutralization products. 47. The process of claim 35, wherein said halide containing organic compound is a polychlorinated biphenyl. 48. A process for removal of a halide from a halide containing organic compound, the process comprising the steps of: dissolving a halide containing organic compound in a solvent of a hydrocarbon or oil; exposing the solvent having a halide containing organic compound dissolved therein, in the presence of hydrogen and a nitrogen containing compound, to a catalyst which is capable, in the presence of hydrogen, of converting the halide in the halide containing organic compound to hydrohalic acid, at a pressure and at an elevated temperature and for a time sufficient to convert the halide in the halide containing organic compound to hydrohalic acid; and neutralizing the resulting hydrohalic acid with the nitrogen containing compound at a pressure and at an elevated temperature to form a hydrohalic acid neutralization product that does not substantially precipitate on said catalyst. 49. The process of claim 48 further comprising the step of adding a compound to said solvent, wherein said compound is transformed into a nitrogen containing compound under the conditions of said process. 50. The process of claim 48 further comprising the step of: neutralizing any catalyst acid sites with the nitrogen containing compound. 51. The process of claim 48 further comprising the step of: removing the exposed solvent from the catalyst; and separating non-solvent materials from the exposed solvent. 52. The process of claim 48 wherein said neutralizing of the hydrohalic acid formed with the nitrogen containing compound results in a neutralization product(s) comprising a neutralization product(s) selected from the group consisting of vaporized ammonium halide and dissociated ammonia and gaseous hydrohalic acid, and the process further comprises the steps of: removing the exposed solvent from the catalyst; and separating non-solvent materials from the exposed solvent. 53. The process of claim 48 wherein the pressure is in the range from about 0.1 MPa to about 50 MPa and the elevated temperature is in the range from about 200 to about 500.degree. C. 54. The process of claim 48 wherein the pressure is in the range from about 1 MPa to about 10 MPa and the elevated temperature is in the range from about 275 to about 375.degree. C. 55. The process of claim 48 wherein the solvent comprises transformer oil. 56. The process of claim 48 wherein the halide is chloride. 57. The process of claim 48 wherein the nitrogen containing compound comprises ammonia. 58. The process of claim 48 wherein the pressure is in the range of from about 1 MPa to about 10 MPa and the elevated temperature is in the range of from about 300 to about 375.degree. C., the solvent comprises transformer oil, the halide is chloride--and the nitrogen containing compound comprises ammonia. 59. The process of claim 48 wherein the pressure and elevated temperature are maintained at a level at which the neutralization product remains substantially in the gaseous phase or disassociated in the gaseous phase such that the catalyst remains substantially uncontaminated by the neutralization products. 60. The process of claim 59 wherein the pressure and elevated temperature are maintained at a level at which the neutralization product remains substantially in the gaseous phase or disassociated in the gaseous phase such that the catalyst remains substantially uncontaminated by the neutralization products. 61. The process of claim 59 further comprising the step of adding a compound to said spent transformer oil, wherein said added compound is transformed into a nitrogen containing compound under conditions of said process. 62. The process of claim 48, wherein said halide containing organic compound is a polychlorinated biphenyl. 63. A process for reduction of an oxygen containing organic compound in a solvent of hydrocarbon or oil, the process comprising the steps of: exposing an oxygen containing organic compound in a solvent of hydrocarbon or oil, in the presence of hydrogen and a nitrogen containing compound, to a catalyst which is capable, in the presence of hydrogen, of reducing the oxygen containing organic compound; at a pressure and at an elevated temperature and for at time sufficient to reduce the oxygen containing organic compound; and neutralizing any acid in the exposed solvent and any catalyst acid sites with the nitrogen containing compound at a pressure and at an elevated temperature to form an acid neutralization product that does not substantially precipitate on said catalyst. 64. The process of claim 63 further comprising the step of adding a compound to said solvent, wherein said compound is transformed into a nitrogen containing compound under the conditions of said process. 65. The process of claim 63 further comprising the steps of: removing the exposed solvent from the catalyst; and separating non-solvent materials from the exposed solvent. 66. The process of claim 63 wherein the pressure is in the range from about 1 MPa to about 10 MPa and the elevated temperature is in the range of from about 275 to about 375.degree. C. 67. The process of claim 63 wherein the solvent comprises transformer oil. 68. The process of claim 63 wherein the halide is chloride. 69. The process of claim 63 wherein the nitrogen containing compound comprises ammonia. 70. The process of claim 63 wherein the pressure and elevated temperature are maintained at a level at which the neutralization product remains substantially in the gaseous phase or dissociated in the gaseous phase such that the catalyst remains substantially uncontaminated by the neutralization products. 71. The process of claim 70 wherein the pressure and elevated temperature are maintained at a level at which the neutralization product remains substantially in the gaseous phase or dissociated in the gaseous phase such that the catalyst remains substantially uncontaminated by the neutralization products. 72. The process of claim 70 further comprising the step of adding a compound to said spent transformer oil, wherein said added compound is transformed into a nitrogen containing compound under conditions of said process. 73. The process of claim 63, wherein said oxygen containing organic compound is a compound resulting from aging of transformer oil. 74. A process for restoring the electrical properties of spent transformer oil having impaired electrical properties, the process comprising the steps of: (a) exposing spent transformer oil, in the presence of hydrogen and a nitrogen containing compound, to a catalyst which is capable, in the presence of hydrogen, of: (i) converting any halide in said spent transformer oil to hydrohalic acid; and (ii) reducing any oxygen containing organic compound in said spent transformer oil; the reaction conditions and time of said exposure being sufficient to restore the electrical properties of said transformer oil; (b) neutralizing the resulting hydrohalic acid or other acid formed in (a) with said nitrogen containing compound at a pressure and at an elevated temperature to form an acid neutralization product that does not substantially precipitate on said catalyst; and (c) recovering regenerated transformer oil obtained from step (a). 75. A process for substantially destroying polychlorinated biphenyls in spent transformer oil containing polychlorinated biphenyls, the process comprising the steps of: (a) exposing spent transformer oil, in the presence of hydrogen and a basic nitrogen containing compound, to a catalyst which is capable, in the presence of hydrogen, of converting chlorine in said polychlorinated biphenyls to hydrochloric acid, the reaction conditions and time of said exposure being sufficient to substantially destroy said polychlorinated biphenyls; (b) neutralizing the resulting hydrochloric acid or other acid formed in (a) with said nitrogen containing compound at a pressure and at an elevated temperature to form an acid neutralization product that does not substantially precipitate on said catalyst; and (c) recovering regenerated transformer oil obtained from step (a). -------------------------------------------------------------------------------- |
| PATENT DESCRIPTION |
TECHNICAL FIELD The present invention relates to a process for removal of halide from a halide containing organic compound in a solvent, a process for simultaneous removal of halide from a halide containing organic compound and reduction of an oxygen containing organic compound in a solvent, a process for removal of halide from a halide containing organic compound, a process for reduction of an oxygen containing organic compound in a solvent, a system for removal of halide from a halide containing organic compound in a solvent, a system for simultaneous removal of halide from a halide containing organic compound and the reduction of an oxygen containing organic compound in a solvent, and a system for reducing an oxygen containing organic compound in a solvent. BACKGROUND OF THE INVENTION Many countries have, or are in the process of, imposing severe limits on the concentration of chlorinated hydrocarbon compounds permitted to be present in a wide range of materials used in industrial and other environments. Typical such compounds include polychlorinated biphenyls (PCBs), hexachlorobenzene, DDT and dioxins as well as hydrocarbon oils containing chlorinated aromatic compounds such as polychlorinated biphenyl compounds which are commonly present as one of the waste products in used or spent oils especially transformer oils and other similar liquids. Such materials are commonly destroyed by high temperature incineration, but this route is expensive and not permitted in some countries. Because hydrocarbon transformer oils represent a large capital investment, any commercial process for the destruction of chlorinated organic compounds therein, and especially PCB contaminants in hydrocarbon transformer oils should, ideally, result in a product oil which can be reused in transformers. In principle, this could be accomplished by devising a process which destroys the PCBs, but which is carried out under reaction conditions which do not significantly alter the chemical composition of the hydrocarbon transformer oil. Apart from combustion, either direct or catalysed, there are two main types of processes used to remove PCBs from oils. In one, the PCBs are reacted with sodium metal under specialised process conditions. Several variations of this route have been described (1-3). In general, this is a difficult process to scale up, requires routine handling of hazardous chemicals, and is likely to be operated as a batch process. It is uncertain if this approach can routinely result in a hydrocarbon transformer oil product which can be reused. In another, (4-9) hydrocarbon oil containing the PCBs is reacted with hydrogen over a catalyst. In these processes, the hydrogen chloride formed in the course of the reaction moves through the reactor unchanged, and is washed from the reaction products only after these leave the reactor. These processes were exclusively designed to destroy the PCBs, and were not designed to recover an oil having the specific dielectric and other properties required for a high quality hydrocarbon transformer oil. Indeed, the coexistence of the hydrocarbon transformer oil and the hydrogen chloride gas in the catalytic reactor at high temperatures and pressures is detrimental to the stability of the catalyst and to the chemical composition of the hydrocarbon oil. Its presence, and the reactions the hydrogen chloride can undergo will render the oil unsuitable for subsequent use as hydrocarbon transformer oil. Over time oils will gradually deteriorate due to oxidation of the hydrocarbons and contamination by other impurities. It is desirable to remove the oxidised species as the presence of these species can significantly reduce the electrical properties of the oil. It is also desirable to remove any organohalogen compounds as they may also affect the properties of oil and acid generated from them can cause a breakdown of the oil if the oil is hydrogenated by standard methods to remove the oxidised species. Particular examples of organohalogen compounds that may generate acids include polychlorinated biphenyls (PCBs), chlorinated napthalenes, chlorinated benzenes and halogenated solvents. Eventually, such degraded and contaminated oil must be withdrawn, as further use greatly reduces the efficiency of transformer operation and can ultimately lead to failure of the transformer. Such degraded oil is generally disposed as low grade fuel oil, valued at less than 1/4 its original cost. When the oil is hydrogenated by standard methods significant breakdown of the oil during hydrogenation by standard methods can also be caused by the catalyst itself, usually due to acidic sites on the catalyst support. Oils such as hydrocarbon transformer oils represent a large capital investment. Accordingly, there is a need to develop a cheap, effective and robust method to regenerate the deteriorated oil. Ideally, the process results in a product oil which can be reused for its original use. For transformer oils, this means regenerating an oil which has electrical properties equivalent to the original oil. Ideally, the process would reverse the oxidation reactions by converting the oxidised species back into hydrocarbons, but which is carried out under reaction conditions which do not significantly alter the chemical composition of the oil. The total transformer oil inventory in use throughout Australia is around 240 million liters. At a cost of about $1000/tonne, this material has a replacement value of approximately $214 million. In the recent Australian report of the Independent Panel on Intractable Waste (1992) estimated that about 67,000 tonnes of this oil, valued at almost $60 million, is contaminated with PCBs (polychlorinated biphenyls). State and Federal Governments are currently developing legislation to restrict the further use, storage and disposal of transformer oil contaminated with toxic PCBs, and are committed to the removal of these materials from the environment. The treatment or disposal of this oil poses a serious problem for its owners in the light of the decision of the federal government to abandon plans for construction of a toxic waste incinerator in Australia, and also to ban export of PCB contaminated materials to overseas incinerators. These decisions virtually force the development of an indigenous technology for the destruction of such toxic materials. The transformer oil inventory in Australia and elsewhere clearly constitutes a major resource within the electricity generating and distribution industries. At present, there is no process available which can economically regenerate the dielectric properties of degraded transformer oils and at the same time remove any PCB contamination. Further, there is a need for a process capable of destroying halogenated hydrocarbons generally. OBJECTS OF INVENTION Objects of the present invention are to provide a process for removal of halide from a halide containing organic compound in a solvent, a process for simultaneous removal of halide from a halide containing organic compound and reduction of an oxygen containing organic compound in a solvent, a process for removal of halide from a halide containing organic compound, a process for reduction of an oxygen containing organic compound in a solvent, a system for removal of halide from a halide containing organic compound in a solvent, a system for simultaneous removal of halide from a halide containing organic compound and the reduction of an oxygen containing organic compound in a solvent, and a system for reducing an oxygen containing organic compound in a solvent. DISCLOSURE OF THE INVENTION According to a first embodiment of the present invention, there is provided a process for removal of halide from a halide containing organic compound in a solvent, the process comprising: exposing a solvent having a halide containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to a catalyst which is capable, in the presence of hydrogen, of converting the halide in the halide containing organic compound to hydrohalic acid, at a pressure and at an elevated temperature and for a time sufficient to convert the halide in the halide containing organic compound to hydrohalic acid; and neutralising the hydrohalic acid so formed with the hydrogen halide scavenger. Examples of reactions included within (but not restricting) the scope of the process of the first embodiment are as follows: Destruction of Chlorinated Organics ##STR1## Neutralisation of Hydrochloric Acid ##STR2## where R.sup.1 -R.sup.7 are organic moieties which may be the same or independently different from one another. Further all or part of the added amines in equations (Ib), (Ic) and (Id) may react with hydrogen to give less substituted amines and/or ammonia: ##STR3## Clearly the basic products of (Ib') to (Id'") are also hydrogen chloride scavengers. Hydrogen halide scavengers are not restricted to ammonia and amines as many nitrogen-containing substance which will generate ammonia or an amine under the conditions of the process will suffice. For example: ##STR4## According to a second embodiment of the present invention, there is provided a process for simultaneous removal of halide from a halide containing organic compound and reduction of an oxygen containing organic compound in a solvent, the process comprising: exposing a solvent having a halide containing organic compound and an oxygen containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to a catalyst which is capable, in the presence of hydrogen, of: (i) converting the halide in the halide containing organic compound to hydrohalic acid; and (ii) reducing the oxygen containing organic compound; at a pressure and at an elevated temperature and for a time sufficient: (a) to convert the halide in the halide containing organic compound to hydrohalic acid; and (b) to reduce the oxygen containing organic compound; and neutralising the hydrohalic acid formed in (a) with hydrogen halide scavenger. Examples of reactions included within (but not restricting) the scope of the process of the second embodiment are as follows: Simultaneous Purification of Solvent and Destruction of Chlorinated Organics ##STR5## Neutralisation of Hydrochloric Acid ##STR6## where R.sup.1 -R.sup.8 are organic moieties which may be the same or independently different from one another. According to a third embodiment of the present invention, there is provided a process for removal of halide from a halide containing organic compound, the process comprising: dissolving the halide containing organic compound in a solvent; exposing the solvent having a halide containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to a catalyst which is capable, in the presence of hydrogen, of converting the halide in the halide containing organic compound to hydrohalic acid, at a pressure and at an elevated temperature and for a time sufficient to convert the halide in the halide containing organic compound to hydrohalic acid; and neutralising the hydrohalic acid so formed with the hydrogen halide scavenger. Generally in the first to third embodiments the step of: neutralising any catalyst acid sites with the hydrogen halide scavenger; is also part of the process. Examples of reactions included within (but not restricting) the scope of the process of the third embodiment are as shown for the first embodiment. According to a fourth embodiment of the present invention, there is provided a process for reduction of an oxygen containing organic compound in a solvent, the process comprising: exposing a solvent having an oxygen containing organic compound, in the presence of hydrogen and acid scavenger, to a catalyst which is capable, in the presence of hydrogen, of: (i) reducing the oxygen containing organic compound; at a pressure and at an elevated temperature and for a time sufficient to: (a) reduce the oxygen containing organic compound; and neutralising any acid in the exposed solvent and any catalyst acid sites with the acid scavenger. Examples of reactions included within (but not restricting) the scope of the process of the fourth embodiment are as follows: Purification of Solvent ##STR7## Neutralisation of Acidity ##STR8## where R.sup.2 -R.sup.7 and R.sup.9 are organic moieties which may be the same or independently different from one another and X is an anion either free or incorporated into the catalyst active sites or both. Typically, X includes either oxygen or sulphur. According to a fifth embodiment of the present invention, there is provided a system for removal of halide from a halide containing organic compound in a solvent, the system comprising: a reactor having an inlet and outlet and a catalyst which is capable, in the presence of hydrogen, of converting halide in a halide containing organic compound to hydrohalic acid, for exposing a solvent having the halide containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to the catalyst, at a pressure and at an elevated temperature and for a time sufficient to convert the halide in the halide containing organic compound to hydrohalic acid; and for neutralising the hydrohalic acid so formed with the hydrogen halide scavenger wherein the neutralising results in a neutralisation product(s), that does not substantially precipitate on the catalyst; means for heating the reactor to an elevated temperature wherein the neutralisation product(s) does not substantially precipitate on the catalyst, the means for heating being operatively associated with the reactor; and means for feeding the hydrogen, the hydrogen halide scavenger and the solvent into the inlet the means for feeding being operatively associated with the inlet. According to a sixth embodiment of the present invention, there is provided a system for simultaneous removal of halide from a halide containing organic compound and the reduction of an oxygen containing organic compound in a solvent, the system comprising: a reactor having an inlet and outlet and a catalyst which is capable, in the presence of hydrogen, of converting halide in a halide containing organic compound to hydrohalic acid, and reducing an oxygen containing organic compound, for exposing a solvent having the halide containing organic compound and the oxygen containing organic compound, in the presence of hydrogen and a hydrogen halide scavenger, to the catalyst, at a pressure and at an elevated temperature and for a time sufficient to convert the halide in the halide containing organic compound to hydrohalic acid and to reduce the oxygen containing compound, and for neutralising the hydrohalic acid so formed with the hydrogen halide scavenger wherein the neutralising results in a neutralisation product(s), that does not substantially precipitate on the catalyst; means for heating the reactor to an elevated temperature wherein the neutralisation product(s) does not substantially precipitate on the catalyst, the means for heating being operatively associated with the reactor; and means for feeding the hydrogen, the hydrogen halide scavenger and the solvent into the inlet the means for feeding being operatively associated with the inlet. The systems of the fifth and sixth embodiments may further comprise: means for removing the exposed solvent from the reactor the means for removing being operatively associated with the outlet; and means for separating non solvent materials from the exposed solvent, the means for separating being operatively associated with the means for removing. According to a seventh embodiment of the present invention, there is provided a system for reducing an oxygen containing organic compound in a solvent, the system comprising: a reactor having an inlet and outlet and a catalyst which is capable, in the presence of hydrogen, of reducing an oxygen containing organic compound, for exposing a solvent having the oxygen containing organic compound, in the presence of hydrogen and an acid scavenger, to the catalyst, at a pressure and at an elevated temperature and for a time sufficient to reduce the oxygen containing compound, and for any acid in the solvent and any catalyst acid sites with the acid scavenger wherein the neutralising results in a neutralisation product(s), that does not substantially precipitate on the catalyst; means for heating the reactor to an elevated temperature wherein the neutralisation product(s) does not substantially precipitate on the catalyst, the means for heating being operatively associated with the reactor; and means for feeding the hydrogen, the acid scavenger and the solvent into the inlet the means for feeding being operatively associated with the inlet. The system of the seventh embodiment may further comprise: means for removing the exposed solvent from the reactor the means for removing being operatively associated with the outlet; and means for separating non solvent materials from the exposed solvent, the means for separating being operatively associated with the means for removing. The means for heating the reactor may heat the reactor itself by for example an electrical heater or a steam jacket. Alternatively, the solvent may be preheated prior to entering the reactor and the reactor may be insulated against loss of heat. The reduction of the oxygen containing organic compound may be decarboxylating a carboxylic acid, reducing a carboxylic acid, reducing an alcohol, reducing a peroxide, reducing a hydroperoxide, reducing an ester, reducing an acid halide, reducing a ketone, decarbonylating an aldehyde, reducing an aldehyde and/or reducing an ether, for example (for other examples of possible reduction of oxygen containing organic compounds see J. March, Advanced Organic Chemistry, 3rd Edition (John Wiley & Sons, New York, 1985), D. C. Liotta and M. Volmer, eds, Organic Syntheses Reaction Guide (John Wiley & Sons, Inc., New York, 1991) and R. C. Larock, Comprehensive Organic Transformations (VCH, New York, 1989). One aspect of the invention, is concerned with mild hydrogenation of an oil (such as a transformer oil) in a packed bed catalytic reactor. Under these conditions hydrogen reacts with heteroatoms in the oil itself, and also with PCBs, HCBs and other chlorinated hydrocarbons present. Oxygen present in compounds resulting from ageing of the oil in service is converted to water. Any PCBs, HCBs and other chlorinated species are converted to hydrogen chloride and light hydrocarbons. A basic nitrogen containing compound additive (eg trimethylamine, triethylamine and/or NH.sub.3) is fed to the reactor to ensure that the hydrochloric acid produced does not lead to degradation of the catalyst and to reduce hydrocarbon cracking reactions by reacting with the hydrogen chloride to form ammonium chloride or the like. The pressure and elevated temperature in the reactor are such that ammonium chloride or the like does not substantially precipitate on the catalyst in the catalytic reactor. On leaving the catalytic reactor, the downstream process typically involves separation of gases and light hydrocarbons from the regenerated transformer oil, and washing stages for the product oil to remove chlorides formed as a reaction product of PCB, HCB and other chloro-organics destruction. More particularly, the processes of the first to third embodiments result in the reduction of the halogenated hydrocarbons to the corresponding hydrocarbon and the formation of ammonium halide or similar ammonium compound. In a further embodiment of the invention the processes comprise the additional step of separating the reaction product(s) of the hydrogen halide scavenger and hydrogen halide, separating the reaction product(s) of the hydrogen and contaminants such as oxygen containing organics, and any unused gaseous hydrogen and unused hydrogen halide scavenger from the solvent. In other words, the processes of the first to third embodiments may further comprise: separating reaction products resulting from the exposing of the solvent and the neutralising of the hydrohalic acid, from the solvent. In a preferred embodiment unused gaseous hydrogen can be recycled. The processes of the first to third embodiments may further comprise: neutralising any catalyst acid sites with the hydrogen halide scavenger. The processes of the first to fourth embodiments may further comprise: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. The processes of the first to third embodiments are generally conducted wherein at the pressure and the elevated temperature: the neutralising of the hydrohalic acid formed with hydrogen halide scavenger results in a neutralisation product(s) that does not substantially precipitate on the catalyst, and the processes further comprise: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. More particularly, the processes of the first to third embodiments are generally conducted wherein at the pressure and the elevated temperature: the neutralising of the hydrohalic acid formed with hydrogen halide scavenger results in a neutralisation product(s) comprising a neutralisation product(s) selected from the group consisting of vapourised ammonium halide and dissociated ammonia and gaseous hydrohalic acid, that does not substantially precipitate on the catalyst, and the processes further comprise: removing the exposed solvent from the catalyst; and separating non solvent materials from the exposed solvent. Generally in the processes of the first to third embodiments the halide is selected from the group consisting of fluoride, chloride, bromide and iodide. Typically the halide is chloride. In particularly preferred processes of the first to third embodiments the pressure is in the range 1 MPa-10 MPa and the elevated temperature is in the range 300-375.degree. C., the solvent comprises transformer oil, the halide is chloride and the hydrogen halide scavenger comprises ammonia. The processes of the first to third embodiments are particularly useful for the destruction of chlorinated organics generally including dioxin, polychlorinated biphenyl compounds (PCBs--for examples of different types of PCBs and PCB derivatives see U.S. Pat. No. 5,145,790, the contents of which are incorporated by cross reference) and hexachlorobenzene (HCB) in hydrocarbon oils wherein a hydrocarbon oil containing a polychlorinated biphenyl compound is fed to a catalytic reactor with gaseous hydrogen and at least one hydrogen chloride scavenger. Any catalyst which is capable, in the presence of hydrogen, of converting the halide in the halide containing organic compound to hydrohalic acid, or which is capable of converting the halide in the halide containing organic compound to hydrohalic acid and reducing the oxygen containing organic compound may be used in the process of the invention. Generally the catalyst is used in the form of a catalyst bed. The catalyst may be a typical hydrotreating catalyst having an active metal chosen from molybdenum, tungsten, chromium, iron, cobalt, nickel, Raney nickel, platinum, palladium, iridium, osmium, ruthenium, copper, manganese, silver, rhenium, rhodium, technetium, vanadium, nickel/molybdenum, nickel/tungsten, nickel/chromium, nickel/iron, nickel/cobalt, nickel/platinum, nickel/palladium, nickel/iridium, nickel/copper, nickel/manganese, nickel/silver, nickel/rhenium, nickel/osmium, nickel/rhodium, nickel/ruthenium, nickel/technetium, nickel/vanadium, Raney nickel/molybdenum, Raney nickel/tungsten, Raney nickel/chromium, Raney nickel/iron, Raney nickel/cobalt, Raney nickel/platinum, Raney nickel/palladium, Raney nickel/iridium, Raney nickel/copper, Raney nickel/manganese, Raney nickel/silver, Raney nickel/rhenium, Raney nickel/osmium, Raney nickel/rhodium, Raney nickel/ruthenium, Raney nickel/technetium, Raney nickel/vanadium, molybdenum/tungsten, molybdenum/chromium, molybdenum/iron, molybdenum/cobalt, molybdenum/platinum, molybdenum/palladium, molybdenum/iridium, molybdenum/copper, molybdenum/manganese, molybdenum/silver, molybdenum/rhenium, molybdenum/osmium, molybdenum/rhodium, molybdenum/ruthenium, nickel/tungsten, molybdenum/technetium, molybdenum/vanadium, nickel/molybdenum/platinum, nickel/molybdenum/palladium, nickel/molybdenum/palladium/platinum, Raney nickel/molybdenum/platinum, Raney nickel/molybdenum/palladium, Raney nickel/molybdenum/palladium/platinum, sulfided forms of the foregoing catalysts, and mixtures and alloys thereof (for other examples of catalysts see "Sulphide Catalysts, Their Properties and Applications", 0. Weisser and S. Landa, Pergamon Press, New York, J. B. Hendrickson et al., "Organic Chemistry", New York, McGraw Hill (1970), P. Dini et al., J. Chem Soc. Perkin, II:1479-1482 (1975), R. B. Pierre et al., J. Catalysis, 52:59-71 (1978), Pierre et al., J. Catalysis, 52:230-238 (1978), and B. Coq et al. React. Kinet. Catal. Lett., 27(1):157-161 (1985), the contents of all of which are incorporated by cross reference). Catalyst activation is typically carried out under a pressure of 0.1-50 MPa, more typically 1-20 MPa, even more typically 3-10 MPa, and yet even more typically about 5 MPa, typically at a temperature in the range 100.degree. C.-500.degree. C., more typically 200.degree. C.-400.degree. C., and yet even more typically 225.degree. C.-375.degree. C. by subjecting the catalyst to either H.sub.2 S in hydrogen (typically 1 vol %-30 vol %, more typically 3 vol %-10 vol % of H.sub.2 S in hydrogen) or a hydrocarbon solvent (eg see list of hydrocarbon solvents in this specification) having a sulphided hydrocarbon dissolved therein such as di(C.sub.1 -C.sub.6 alkyl)disulphide, di(C.sub.2 -C.sub.6 alkylene)disulphide or di(C.sub.2 -C.sub.6 alkyne)disulphide (eg dimethyldisulphide) or indeed any substance which can be converted into hydrogen sulphide by reaction with hydrogen. A typical process for sulphiding the catalyst is as follows: (a) After pressurising the system and establishing the hydrogen flow, feed was introduced at a rate of 25-250 ghr.sup.-1. The temperature is then incremented in stages of 10-50.degree. C., typically 25.degree. C., every 15-120 minutes, typically every 30 minutes to 200.degree. C.-275.degree. C., typically 250.degree. C., and held at this point until hydrogen sulfide can be detected in the off-gas (eg by using Drager tubes). After detection of the hydrogen sulfide, the temperature is increased in stages of 10-50.degree. C., typically 25.degree. C., (ensuring a breakthrough of H.sub.2 S each time) to 320-400.degree. C., typically 350.degree. C. The temperature is held at 320-400.degree. C., typically 350.degree. C., for 1-4 hours, typically 2 hours, and then decreased to 100-250.degree. C., typically 200.degree. C., at which point the feed and heaters are turned off and the catalyst allowed to cool slowly under a steady hydrogen flow or under an atmosphere of hydrogen (eg for 5-36 hours, typically 12 hours under 0.1-50 MPa, more typically 1-20 MPa, even more typically 3-10 MPa, and yet even more typically about 1-5 MPa and further even more typically 3.5 MPa). Typically when two catalysts are used, they are used in molar ratios in the range 1:99 to 99:1, more typically, 10:90 to 90:10, even more typically 25:75 to 75:25 and yet more typically 50:50. Typically when three catalysts are used, they are used in molar ratios in the range 1:1:98 to 1:98:1 to 98:1:1, more typically, 10:10:80 to 10:80:10 to 80:10:10, even more typically 33.3:33.3:33.3. Typically when four catalysts are used, they are used in molar ratios in the range 1:1:1:97 to 1:1:97:1 to 1:97:1:1 to 97:1:1:1, more typically, 25:25:25:25. Particularly preferred commercially available catalysts are sulfided Ni/Mo (1-6% Ni/2-15% Mo, typically 2% Ni/7% Mo) supported on .gamma. alumina, platinum supported on .gamma. alumina, and palladium on .gamma. alumina (the latter two catalysts may be simply reduced in hydrogen at elevated temperatures (200-800.degree. C.) prior to use). The processes of the first to third embodiments may further comprise: monitoring the hydrogen halide scavenger content in the solvent after exposing the solvent to the catalyst and adjusting the amount of hydrogen halide scavenger in the solvent exposed to the catalyst and/or the temperature during the exposure and/or the pressure during the exposure whereby there is a detectable amount of hydrogen halide scavenger in the solvent after exposing the solvent to the catalyst such that the amount of hydrogen halide scavenger in the solvent at the time of exposing of the solvent to the catalyst is an amount effective to completely neutralise hydrogen halide and any other acids in the solvent and any acids formed during the exposure of the solvent to the catalyst including neutralising any catalyst acid sites. The processes of the first to third embodiments may further comprise: monitoring the halide content in the solvent prior to exposing the solvent to the catalyst and adjusting the amount of hydrogen halide scavenger and/or hydrogen exposed to the catalyst and/or the temperature during the exposure and/or the pressure during the exposure whereby there is a detectable amount of hydrogen halide scavenger in the solvent after exposing the solvent to the catalyst such that the amount of hydrogen halide scavenger in the solvent at the time of exposing of the solvent to the catalyst is an amount effective to completely neutralise hydrogen halide and any other acids in the solvent and any acids formed during the exposure of the solvent to the catalyst including neutralising any catalyst acid sites. The process of the fourth embodiment may further comprise: monitoring the acid scavenger content in the solvent after exposing the solvent to the catalyst and adjusting the amount of acid scavenger in the solvent exposed to the catalyst and/or the temperature during the exposure and/or the pressure during the exposure whereby there is a detectable amount of acid scavenger in the solvent after exposing the solvent to the catalyst such that the amount of acid scavenger in the solvent at the time of exposing of the solvent to the catalyst is an amount effective to completely neutralise any acids in the solvent and any acids formed during the exposure of the solvent to the catalyst including neutralising any catalyst acid sites. The oxygen containing organic compound is typically a compound resulting from ageing/oxidation of the solvent (eg transformer oil). Advantageously in the processes of the first to fourth embodiments of the invention the hydrogen halide scavenger or the acid scavenger is a basic nitrogen containing compound which is chosen such that the step of neutralising the hydrohalic acid with the basic nitrogen containing compound results in a gaseous or volatile compound under the conditions in the catalytic reactor (which in the case of the first to third embodiments is a function of pressure, temperature and halide content in the reactor and in the case of the fourth embodiment is a function of pressure, temperature and anion content in the reactor) such that the compound does not precipitate in the catalytic reactor and can be readily removed from the catalyst and the catalytic reactor. Any suitable nitrogen compound which is a base or is transformed into a base and which will neutralise hydrogen halide under the reaction conditions of the process of the invention and which under the reaction conditions of the exposure to the catalyst, can be readily removed from the catalyst, may be used in the process of the invention. Typically the hydrogen halide scavenger comprises a nitrogen containing compound which is a base or which is transformed into a base (such as ammonia) in the reactor. The gaseous hydrogen being added to the catalytic reactor may itself independently contain a basic compound such as ammonia. It is particularly desirable to use ammonia gas and/or a nitrogen containing organic basic compound whereby under process conditions, ammonium halide is formed in such a way that it does not substantially precipitate on the catalyst (i.e. it remains dissociated as ammonia and HCl or stays in gaseous phase etc.). Examples of suitable basic nitrogen containing compounds include tri(C.sub.1 -C.sub.7 alkyl)amines including trimethylamine, triethylamine, tripropylamine, or tributylamine etc., di(C.sub.1 -C.sub.7 alkyl)amines including dimethylamine, diethylamine, dipropylamine, dibutylamine, diisobutylamine, or diisopropylamine, etc., C.sub.1 -C.sub.7 alkylamines including methylamine, ethylamine, propylamine, butylamine, isopropyl-amine, isobutylamine, etc., C.sub.2 -C.sub.9 primary, secondary and tertiary alkylideneamines, C.sub.3 -C.sub.9 cycloalkylamines including cyclohexylamine, cyclopentylamino and cycloheptylamino, C.sub.6 -C.sub.12 arylamino, C.sub.7 -C.sub.14 aralkylamino aniline, ammonia and nitrobenzene or mixtures thereof. A basic nitrogen-containing heterocyclic which may be a 5-, 6-, 7-, 8-, 9- or 10-membered monocyclic, bicyclic or polycyclic ring containing from one to three nitrogen heteroatoms and includes any group in which a heterocyclic ring is fused to a benzene ring. Examples of such heterocycles are pyrryl, pyrimidinyl, quinolinyl, isoquinolinyl, indolyl, piperidinyl, pyridinyl, imidazolyl, imidazolidinyl, morpholinyl, pyrrolidinyl, pyrazolyl, pyrazolinyl, tetrazolyl, triazolyl, benzimidazolyl, pyrrolinyl, quinuclidinyl, azanorbornyl, isoquinuclidinyl and the like. e.g. tertiary amines such as trialkyl amines (trimethylamine, triethylamine, pyridines and pyridine bases (4-dimethylaminopyridine, 4-pyrrolidylaminopyridine etc.). The lower alkylamino includes alkylamino having straight or branched chain alkyl moiety having 1-6 carbon atoms, The di- and tri-lower alkylaminos include amino substituted by the same or different and straight or branched chain alkyl moiety having 1-6 carbon atoms. Other examples of amine organic bases include n-amylamine, n-hexylamine, n-octylamine, n-decylamine, laurylamine, palmitylamine, dibutylamine, tributylamine, N,N-dimethyl-benzylamine, N,N,-dimethyl-p-toluidine, phenethyldibutyl-amine, N,N,N',N'-tetramethylhexamethylenediamine, N,N,N'N'-tetramethylpropylenediamine, N'N-diethylbenzylamine, ethylaniline, methylaniline, propylaniline, diethylaniline, dimethylaniline, dipropylaniline, triethylaniline, trimethylaniline, tripropylaniline, N,N-dibutylbenzylamine, phenethyldiethylamine, N,N'di(t-butyl)ethylene-diamine, N-methylmorpholine, N,N-dimethylaminopyridine, N,N-dimethylbutylamine, di(n-butyl)amine, triethylamine, diethylamine, picoline, 2-picoline, 3-picoline, 4-picoline, 2,4-lutidine, 2,6-lutidine, quinoline, pyridines (including pyridine), pyrimidines, quinoxalines, tri-n-propyl-amine, triisopropylamine, and dimethylisoproplamine. The gaseous hydrogen being added to the reactor may also contain a basic nitrogen containing compound. For example the gaseous hydrogen may also contain ammonia. As used herein, the term "alkyl" includes within its meaning straight and branched chain alkyl groups. Examples of such groups are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, amyl, isoamyl, sec-amyl, 1,2-dimethylpropyl, 1,1-dimethyl-propyl, hexyl, 4-methylpentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1,2,2-trimethylpropyl, 1,1,2-trimethylpropyl, and the like. As used herein, the term "cycloalkyl" refers to mono- or polycyclic alkyl groups, or alkyl substituted cyclic alkyl groups. Examples of such groups include cyclopropyl, methylcyclopropyl, cyclobutyl, methylcyclobutyl, cyclopentyl, methylcyclopentyl, ethylcyclopentyl, cyclohexyl, methylcyclohexyl, ethylcyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl and the like. As used herein, the term "alkylidene" includes reference to unsaturated divalent alkyls. Examples of such radicals are CH.sub.2 .dbd.CH--, HC(.dbd.CH.sub.2)CH.sub.2 --, CH.sub.3 CH.dbd.CH--, CH.sub.3 CH.sub.2 CH.dbd.CH--, and CH.sub.3 CH.dbd.CHCH.sub.2. The term also refers to such radicals in which one or more of the bonds of the radical from part of a cyclic system and at least one of the cyclic atoms is nitrogen. Examples of such radicals are groups of the structure ##STR9## As used herein, the term "aryl" refers to single, polynuclear and fused residues of aromatic hydrocarbons or aromatic heterocyclic ring systems. Examples of such groups are phenyl, biphenyl, naphthyl, pyridyl, thienyl, furyl, pyrryl, indolyl, pyridazinyl, pyrazolyl, pyrazinyl, thiazolyl, pyrimidinyl, quinolinyl and isoquinolinyl. As used herein, the term "aralkyl" refers to alkyl groups substituted with one or more aryl groups as previously defined. Examples of such groups are benzyl, 2-phenylethyl and 1-phenylethyl. The concentration and amount of hydrogen halide scavenger compound added to the reactor will depend upon the concentration of halide containing organic compound(s) such as PCBs in the solvent (such as hydrocarbon oil) and the actual hydrogen halide scavenger compound being used. Ideally, the amount and concentration of hydrogen halide scavenger compound present is generally sufficient to react with all the hydrogen halide formed as a result of the reduction of the halide containing organic compound(s) present in the solvent (i.e. of hydrogen halide scavenger compound present is generally at least stoichiometric or greater than stoichiometric of the amount of HCl formed). This will depend upon the hydrogen halide scavenger compound selected and its ability to react with hydrogen halide. Generally the amount of hydrogen halide scavenger is at least equal to or greater than stoichiometric (i.e. Cl (corresponding to total Cl content of solvent mixture):hydrogen halide scavenger is generally 1M:1M or 1M:>1M (typically between 1M and 100M, more typically between 1M and 10M and more typically between 1M and 3M). The hydrogen halide scavenger compound may be added to the solvent such as, for example, contaminated transformer oil, prior its being added to a catalytic reactor or it may be added directly to the reactor or it may be added to the gaseous hydrogen entering the reactor. Alternatively the hydrogen halide scavenger may be added to the gaseous hydrogen prior to it being introduced to the catalytic reactor. Generally the reaction takes place under elevated temperature and pressure in a catalytic reactor. The operating temperature and pressure are adjusted to take into account the halide content of the feed solvent (which can be monitored, batchwise or continuously) so that deposition of NH.sub.4 Cl formed as a consequence of the hydrogen halide scavenger reacting with HCl in the reactor is minimised or substantially prevented in the reactor. Any suitable solvent capable of dissolving the relevant halogenated organic compound(s) and which can substantially withstand reaction conditions in the catalytic reactor may be used (the suitability of a solvent may be determined by simple trial and error). Clearly the choice of solvent will be dependent upon the type of halogenated organic compound to be destroyed such that the halogenated organic compound is able to be dissolved in said solvent. These solvents include aromatic compounds, cycloaliphatic compounds, aliphatic-substituted aromatic compounds, cycloaliphatic-substituted aromatic compounds, aliphatic-substituted cycloaliphatic compounds, and mixtures thereof. These compounds include substantially hydrocarbon compounds as well as purely hydrocarbon compounds. The term "substantially hydrocarbon" is used herein to mean that the compounds contain no non-hydrocarbon substituents or non-carbon atoms that significantly affect the hydrocarbon characteristics or properties of such compounds relevant to their use herein as solvents. The aromatic compounds can be mononuclear or polynuclear. The aliphatic substituents on the aromatic compounds can be straight chain hydrocarbon groups of 1 to about 7 carbons, cyclic groups of about 3 to about 9 carbons, or mixtures thereof. The aromatic compounds can be mono-substituted or poly-substituted. The poly-substituted aromatic compounds are-preferably di-substituted. The cycloaliphatic compounds can have from about 3 to about 9 ring carbon atoms, preferably 5 or 6 ring carbon atoms, and can be saturated or unsaturated. Examples include cyclopropane, cyclobutane, cyclopentane, cyclopentene, 1,3-cyclopentadiene, cyclohexane, cyclohexene, 1,3-cyclo-hexadiene, etc. The aliphatic substituents on the aliphatic-substituted cycloaliphatic compounds can be Straight chain hydrocarbon groups of 1 to about 7 carbon atoms, preferably 1 to about 3 carbon atoms. The rings of the cycloaliphatic compounds can be mono-substituted or poly-substituted. The poly-substituted compounds are preferably di-substituted. Examples include methylcyclopentane, methylcyclohexane, 1,3-dimethylcyclohexane, 3-ethylcyclopentene, 3,5-dimethylcyclopentene, etc. Typically the solvent is a liquid hydrocarbon solvent. Suitable liquid hydrocarbons include diesel oil, straight run distillates, kerosene, transformer oil, motor oil, aromatics such as benzene, tetralin, pseudocumene, o-xylene, m-xylene, p-xylene, ethylbenzene, isopropylbenzene, mesitylene, naphthalene, anthracene, styrene, 1-methylnaphthalene, 1,2-dimethylnaphthalene, 1,6-dimethylnaphthalene, 1,2,3,4-tetrahydronaphthalene, butylbenzene, sec-butylbenzene, isobutylbenzene, tert-butylbenzene, cyclohexylbenzene, p-cymene, cumene, 4-tert-butyltoluene, and toluene, or aliphatics such as cyclohexane, cyclohexene, dipentene, d-limonene, 1-limonene, octane, methylcyclohexane, ethylcyclohexane, mesitylene, hexane, 2-pinene, 2(10)-pinene, 1-pentene, 2-pentene, cis-2-pentene, trans-2-pentene, 1-hexene, 1-heptene, 1-octene, 2-octene, cis-2-octene, trans-2-octene, 1-nonene, 1-decene, 1-dodecene, 1-tridecene, propane, butane, 2-methylpropane, cyclopentane, pentane, 2-methylbutane, 2,2-dimethylpropane, methylcyclopentane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylhexane, 2,2,3-trimethylpentane, 2,2,4-trimethylpentane, 2,2,3,3-tetramethylbutane, nonane, decane, 1,1'-bicyclohexyl, dodecane, tridecane, 2,2,5-trimethylhexane, decahydronaphthalene, trans-decahydronaphthalene, cis-decahydronaphthalene, 3-methylhexane, 2,3-dimethylpentane, 2,4-dimethylpentane, 1,2-dimethylcyclohexane, cis-1,2-dimethylcyclohexane, trans-1,2-dimethylcyclohexane, heptane, or mixtures of any of the foregoing. Alternatively, the solvent may be an oil such as a mineral oil eg paraffin oil, (including an oil used in transformers), a vegetable oil eg arachis oil, olive oil, sesame oil, groundnut oil, peanut oil or coconut oil, a fish oil eg tuna oil, mackeral oil, sand eel oil, menhaden oil, anchovy oil, sardine oil, horse mackeral oil, salmon oil, herring oil, cod oil, capelin oil, pilchard oil, sprat oil, whale oil, Pacific oyster oil, Norway pout oil, seal oil and sperm whale oil or a plant oil eg pine oil, wheat germ oil and linseed oil). Further examples of solvents that may dissolve halogenated organic compounds may be found in "Chemical Safety Data Sheets", Volume 1: Solvents, The Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge, United Kingdom and Techniques of Chemistry, Volume II, "Organic Solvents", J. A. Riddick, W. B. Bunger and T. K. Sakano, 4th edition, A. Weissberger editor, J. Wiley & Sons, New York, 1986, the contents of both of which are incorporated herein by cross reference. Ideally enough solvent is mixed with the halogenated organic compound such that all of the halogenated hydrocarbon is dissolved. The amount of solvent will accordingly depend upon the ability of said solvent to dissolve the halogenated organic compound. In a preferred embodiment the concentration of halogenated organic compound in the solution formed in step one is up to 35 wt %, typically up to 10 wt %, more typically 0.1-5 wt %. Alternatively, in terms of ppm the concentration of halogenated organic compound is typically 0.1 ppm to 10,000 ppm, more typically 1 ppm-1000 ppm. The amount of gaseous hydrogen added to the reactor will depend on the level of halogenated organic compound(s) to be destroyed and other contaminants present in the oil and may varied by altering the pressure in the reactor during the exposure (in particular this can be generally achieved by adjusting the input the hydrogen pressure and ammonia pressure) or the hydrogen to oil ratio or both. The pressure (and elevated temperature) are generally chosen such that the reaction product of the hydrogen halide scavenger and hydrogen halide (or in the case of the fourth embodiment the reaction product of the acid scavenger and acid catalyst sites or other acids) does not substantially precipitate onto the catalyst during the exposure. Typically the pressure at which hydrogen is delivered to the catalytic reactor (or if another gas such as ammonia is also added to the reactor, the pressure of ammonia and hydrogen added to the reactor) is such that the pressure in the reactor during the exposure is in the range of 0.01-50 MPa, more typically 1-20 MPa, even more typically 2-10 MPa, yet even more preferably 3-7 MPa. A more typical pressure during the exposure in the catalytic reactor is in the range 3-5 MPa. The pressure in the catalytic reactor during the exposure is generally monitored with a pressure gauge. The elevated temperature will typically depend upon the catalyst being used and the level of halogenated organic compound(s) present in the contaminated oil. The elevated temperature (and pressure) are generally chosen such that the reaction product of the hydrogen halide scavenger and hydrogen halide (or in the case of the fourth embodiment the reaction product of the acid scavenger and acid catalyst sites or other acids) does not substantially precipitate onto the catalyst during the exposure. Typically the elevated temperature is in the temperature range 200-550.degree. C. more typically, 200-500.degree. C. More typically the temperature of the reaction is in the range 250-350.degree. C. Ideally the process of the invention in conducted at a temperature which maximises the destruction of the halogenated hydrocarbons while minimising thermal destruction of the solvent. In a preferred embodiment the catalytic reactor is maintained at a temperature of more typically 275-375.degree. C. and even more typically 300-350.degree. C. The efficiency of reduction of halogenated organic compound(s) and/or oxidised organics present in the solvent is dependent upon a number of factors. One of the important factors is the residency of the solvent to be purified in relation to catalyst. Ideally, the residency time is sufficiently long so that substantial conversion of all the required halogenated organic compound(s) and/or oxidised organics present in the solvent to be occurs so that they are substantially reduced. The optimum residency time of the gas is dependent on a number of factors including the type of solvent to be purified, the catalyst selected, the temperature selected and the impurities to be removed. The hourly space velocity (i e. grams of solvent fed to the reactor per gram or catalyst per hour) of solvent fed to the catalytic reactor will depend upon the level of halogenated organic compound(s) and/or oxidised organics present in the solvent and the type of reactor being used and the level of other variants. A preferred hourly space velocity is in the range of 0.1 to 10 grams of solvent per gram of catalyst per hour. Hourly space velocities (GHSV at STP) typically between 1 and 3600, more typically 3 and 2400 liter feed solvent per kg of catalyst per hour (l/kg/hr), typically 1 to 1800 l/kg/hr, more typically 20 to 500 l/kg/hr and even more typically 50 to 275 l/kg/hr. Typically the contact time of the solvent with the catalyst is between 1 sec and 5 minutes, more typically 0.15 seconds and 20 seconds and even more typically between 0.25 and 5 seconds. Typically the solvent is preheated prior to contact with the catalyst. To optimise the residency time a number of features may be altered. These include the path length of the gas over the catalyst, pressure, temperature of the reactor, the flow rate of the gas and the volume of the reactor. The catalyst may be in the form of powder, granules, discs, pellets, monoliths or other suitable form. The catalyst may be in the form of pure catalyst or alternatively it may be held together with a binder and/or may be coated or deposited on a support or carrier by techniques well known in the art (e.g. by vacuum deposition, impregnation, electrodeposition). Suitable binders or support materials include but are not limited to alumina including .alpha.-alumina, mullite, cordierite, mullite aluminium titanate, magnesia, zirconia, zirconia spinels, titania, silica-alumina including amorphous silica-alumina, and clays and mixtures thereof. Small amounts of other materials such as zirconia, titania, magnesia and/or silica may be present. The amount of binder may be 3-50 wt % of the catalyst, more typically 5 to 30 wt % base on the total weight of the catalyst. Typically, the catalyst has a surface area to volume ratio of at least 0.5 m.sup.2 /gm, more typically between 25 and 500 m.sup.2 /g, and even more typically between 50 and 250 m.sup.2 /g. The reactor may be a single pass reactor packed with the catalyst, such as for example a particulate catalyst disposed in a fixed bed within the reactor or a catalyst deposited on or impregnated in a ceramic foam carrier (e.g. ceramic foams made from the aforementioned refractory oxides particularly alumina and .alpha.-alumina) disposed within the reactor, or a multiple pass reactor packed with the catalyst. The catalyst may be arranged fixedly within the reactor so as to provide a high tortuosity for the feed gas (typically between 1.0 and 10.0, more typically 1.3 to 4.0; "tortuosity" with reference to a fixed catalyst bed is the ratio of the pathlength of gas flowing through the bed to the length of the shortest straight line through the bed). Alternatively, the catalyst may be in the form of a fluidised bed. The reactor may be operated so that the feed gas contacts the catalyst under isothermal conditions or adiabatic conditions ("adiabatic" referring to reaction conditions wherein substantially all heat loss and radiation from the catalyst bed is prevented except for the heat leaving in the exit gas from the reactor). As far as removal of PCB and other chlorinated organics as well as regeneration of transformer oils are concerned, the process of the second embodiment is typically able to provide a processed transformer oil having (a) A dielectric dissipation factor of 5-6.times.10.sup.-3 (max); (b) A resistivity >200 Gohmm; (c) A dielectric strength >60 kV; (d) An acidity of 0.01 to 0.03 mg KOH/g (max); (e) Interfacial tension of >30 mN/M; and (f) PCB content <0.1 mg/kg. Advantages of the process of the invention are as follows: (i) High temperature incineration has been a widely used method for disposing of toxic wastes overseas. However, the potential formation of dioxins during incineration is the single most important factor raised in public opposition to incineration as a solution to toxic waste destruction in Australia. A significant benefit of this new processes is that the experimental conditions make the formation of dioxins totally impossible. (ii) Apart from their ability to destroy PCB contamination and other chlorinated organic contamination, the processes of the invention offer an entirely new approach for the regeneration and recycling of oxidised, and therefore unusable, transformer oils. As already indicated, these are a valuable component of the national electricity grid. BRIEF DESCRIPTION OF DRAWINGS Preferred embodiments of the invention are described below with reference to the following drawings in which: FIG. 1 depicts schematically a system for the simultaneous removal of chlorine from a chlorine containing organic compound and the reduction of oxygen containing organic compounds in spent transformer feed oil; FIG. 2 depicts the temperature at which ammonium chloride deposits as a function of chlorine content in a feed oil at a of pressure 3.5 MPa; FIG. 3 depicts schematically a process flowsheet for the removal of chlorinated hydrocarbons; FIG. 4 is a graph of hydrogen consumption vs product chlorine content--Run 2; FIG. 5 is a graph of hydrogen consumption vs dielectric dissipation factor--run 2; FIG. 6 is a graph of hydrogen consumption vs reciprocal resistivity--run 2; FIG. 7 is a graph of product sulfur content vs time on stream--run 4; FIG. 8 is a graph of product nitrogen content vs time on stream--run 4; FIG. 9 is a graph of product chlorine content vs time on stream--run 4; FIG. 10 is a graph of dielectric dissipation factor vs time on stream--run 4; FIG. 11 is a graph of dielectric strength vs time on stream--run 4; FIG. 12 is a graph of interfacial tension vs time on stream--run 4; FIG. 13 is a graph of resistivity vs time on stream--run 4; FIG. 14 depicts schematically a pilot plant system used in various experiments; and FIG. 15 depicts schematically a catalytic reactor used in various experiments. BEST MODE AND OTHER MODES OF CARRYING OUT THE INVENTION The process described may be configured as a mobile transformer oil treatment unit capable of processing 10,000 liters per day in continuous operation. It is anticipated that such a unit will be suitable for on-site retreatment of oils in transformers containing 10,000 liters of oil or greater. The maximum oil volumes in transformers on the New South Wales supply system are around 110,000 liters with around 94% of network and 42% of distribution transformer oil volume in units greater than 10,000 liters. It is envisaged that in treating transformer oils on-site the particular transformer will be taken off-line and its oil transferred to a transportable storage tank of suitable volume that is also brought on-site. Oil will be processed from this tank through the hydrogenation unit and regenerated oil transferred to a transportable product oil tank. Regenerated oil will then be returned to the transformer via a vacuum de-gassing unit. The treatment plant described here does not include the de-gassing unit, mobile units for this purpose being already in existence within the power authorities. Retreatment of transformer oils on site will require the assembly of the following facilities in the vicinity of the transformer: (a) Spent oil and regenerated oil tankage; (b) Hydrogenation process module; (c) Hydrogen supply module; (d) Hydrogenation control and monitoring unit; and (e) Vacuum de-gassing unit. FIG. 1 depicts a system 100 for the simultaneous removal of chlorine from a chlorine containing organic compound and the reduction of oxygen containing organic compounds in spent transformer feed oil 101. Spent feed oil 101 from an on-site storage tank (not shown) is introduced to process 100 via a positive displacement charge pump (not shown) where the oil pressure is raised to around 4.3 MPa. Feed oil 101 passes via line 102 through high pressure vent condenser 103. Feed oil 101 passes in turn via line 104 to product oil heat exchanger 105 where it is heated to 285.degree. C. Feed oil 101 then passes via line 106 to final feed heater 107, where it is raised to a temperature of 355.degree. C. Heater 107 is an electrical element immersion heater designed to limit maximum oil contact temperatures to around 380.degree. C. Feed oil 101 then passes into reactor 109 via line 108. Recycle hydrogen 110 and fresh hydrogen 111 are introduced into reactor 109 via lines 112 and 113, and 114 and 113 respectively. Ammonia 115 is also introduced into reactor 109 via lines 116 and 113. The chlorine (and/or oxygen content) of feed oil 101 may be monitored by monitor 164 via line 163 which in turn may make appropriate adjustments to the amount of input hydrogen chloride scavenger and input hydrogen via lines 165 and 166 (the amount of chlorine exiting the reactor as ammonium chloride may also be independently or simultaneously monitored by monitor 164 via an appropriate line (not shown) which in turn may make appropriate adjustments to the amount of input hydrogen chloride scavenger and input hydrogen via lines 165 and 166). The combination reacts in reactor 109 at approximately 330.degree. C. and 3.5 MPa. The reactor comprises a single packed bed of a conventional hydrotreating catalyst (which has been sulphided) operating as a trickle bed. At the reaction conditions approximately 7% of the transformer oil enters the vapour phase and around 2.5% of the hydrogen is dissolved in the oil. During reaction nitrogen and sulphur present as heteroatoms in feed oil 101 are converted to ammonia and hydrogen sulphide. Conversion rates are around 44% and 91% respectively. Chlorine present in the oil is derived primarily from PCB contamination of the oil. Chlorine is converted to HCl with a conversion level of 99.7%. Oxygenated degradation products present in the feed oil 101 are also hydrogenated with the oxygen being removed as water. Generally the quantities of water produced are small. Ammonia 115, introduced to reactor 109 to inhibit catalyst deactivation by HCl, and the HCl itself remains dissociated in the gas phase at the reactor conditions of temperature and pressure. Generally reactor 101 is designed so that at the potential pressures of these components in the reactor effluent vapour phase for a typical chlorine content in feed oil, deposition of solid NH.sub.4 Cl does not occur above approximately 240.degree. C. In addition to extraction of heteroatoms and hydrodechlorination of PCBs, hydrogen is consumed in hydrogenating the oil itself to a small degree. This results in the generation of some light hydrocarbon vapours and liquids in the boiling range below that of the parent oil and these are subsequently separated out within the hydrotreating system and the separate vacuum de-gassing unit. Effluent leaving reactor 109 passes first to heat exchanger 105 via line 117 where it is cooled to 235.degree. C. against incoming feed oil. This temperature is marginally above that estimated for the onset of NH.sub.4 Cl deposition and permits maximum cooling of the oil prior to contact with wash water. Under these conditions partial deposition of solid NH.sub.4 Cl may occur and some fraction of this material could then remain in exchanger 105 as a fouling deposit. As the total quantity of NH.sub.4 Cl available for deposition is small, approximately 2.75 kg or 1.8 liters over the course of processing the maximum 110,000 L transformer volume, and only a small fraction of this may deposit in exchanger 105, appropriate configuration of exchanger 105 to account for this possibility wil permit runs of this volume to be satisfactorily completed. Cooled reactor effluent from heat exchanger 105 then passes in-line static mixer 118 via lines 119 and 120 where it is then contacted directly with wash water from the final product oil wash stage via lines 121, 122 and 120. The mixed stream is then passed from in-line static mixer 118 to high pressure separator 124 via line 123. Oil, water and gas phases are split in separator 124 which operates at 174.degree. C. and 3.3 MPa. Sufficient wash water is introduced to ensure that a liquid phase is present to dissolve NH.sub.4 Cl as it is precipitated while minimising the quantity of aqueous effluent to be discharged from the plant. Wash water is used in the system at a rate of 27 kg/h representing a wash water to feed oil 101 rate of 7.46.times.10-2 kg/kg feed oil. In excess of 90% of this water leaves separator 124 in the vapour stream with H.sub.2 S, trace HCl, light hydrocarbons and some transformer oil vapours. The separator waste water phase containing NH.sub.4 Cl, NH.sub.3 and H.sub.2 S is sent to a neutraliser drum (not shown) via line 126 for treatment. Oil from the high pressure separator 124 passes to heat exchanger 137, via line 136, where it is cooled to 122.degree. C. (which can be arranged (not shown) so that it is against incoming feed oil 101). Product oil leaving condenser 137 passes to a let-down valve 139 via line 138 where the pressure is reduced to 221 kPa ahead of low pressure separator 141 to which it passes via line 140. Overhead vapours from this flash stage contain the majority of water and dissolved non-condensable hydrocarbons in the oil reducing the non-condensables load on the final de-gassing plant. These vapours additionally contain NH.sub.3 and H.sub.2 S and pass to low pressure caustic scrubber 133 via line 142 prior to venting to catalytic oxidation unit (not shown) via lines 134 and 135. A very small liquid water flow is separated in the flash drum comprising low pressure separator 141 and the main product oil flow passes to air cooled product cooler 144 via line 143 where its temperature is reduced to 50.degree. C. Fresh demineralised water 146 is introduced via line 145 into the product oil stream in line 147 and the combined flow passes via line 148 through in-line mixer 149 and line 150 to wash water Separator 151. Washed product oil 153 is then removed from separator 151 to an oil storage tank (not shown) via line 152 ahead of de-gassing. Separated water is passed back to the primary wash stage in high pressure separator 124 via lines 121, 122 and 120, static mixer 118 and line 123. A small vapour flow from the wash water separator 151 is passed to the low pressure caustic scrubber 133 (via a line not shown). Vapour from the high pressure separator 124 passes to the high pressure vent condenser 103 via line 127 where it is cooled to 50.degree. C. against incoming feed oil 101. Condensate, which is mainly water and small quantities of condensable hydrocarbons, is passed to waste oil separator 131 via line 128, valve 129 and line 130. Separated waste oil 154 is collected via line 155 in a drum for separate off-site disposal. Vent gases from separator 131 are passed to the low pressure caustic scrubber 133 via line 132. Separated water is passed to a waste water neutraliser (not shown) via line 156. Non-condensable gases from the high pressure vent condenser 103 comprise mainly hydrogen, light hydrocarbons, H.sub.2 S and NH.sub.3. These are passed to the high pressure caustic scrubber 158 via line 157 where H.sub.2 S is removed and collected into the caustic solution. Gases pass counter-current to caustic solution in a packed tower. H.sub.2 S is removed with the recirculated solution becoming saturated in NH.sub.3. A sufficient quantity of caustic is provided to contain the H.sub.2 S generated in a 110,000 liter transformer run with spent caustic disposed of to appropriate waste processing facilities off-site. Scrubbed gas from scrubber 158 is recycled via lines 159, 112 and 113 to reactor at around 3.27 MPa. Non-condensable gases produced in reactor 109 are removed from the system by taking a purge gas flow prior to compression. Purge gases are passed via lines 159, 160, valve 161, lines 162 and 135 to a catalytic oxidation unit (not shown) for combustion and combustion gases released to the atmosphere. Recycle goes comprising H.sub.2, light hydrocarbons, NH.sub.3 and water are recompressed to 4.1 MPa and pass back to reactor 109. Water streams from the HP and LP Separators 158 and 133 and waste oil separator 131 contain dissolved H.sub.2 S, NH.sub.4 Cl, trace HCl and trace H.sub.2. These pass to waste water neutraliser (not shown) after neutralisation with HCl solution. Neutralised water is stripped with a flow of scrubbed purge gas in a packed tower on the inlet to the waste water neutralise. Separated water from this drum is passed to drain with its dissolved NH.sub.4 Cl. Any hydrocarbon liquids captured accumulate in the drum and are removed periodically. Stripper gas is passed back to the vent gas flow leaving the low pressure caustic scrubber 133. Purge gas from the high pressure gas recirculation loop and all scrubbed vent gases pass together to the catalytic oxidation unit (not shown) where they are burnt at approximately 600.degree. C. with approximately 400% excess air. Incoming air is provided with electrical pre-heating for start-up and for trimming catalyst bed temperature control if required. Optimum operating conditions for catalytic reactor 109 in terms of H.sub.2 and hydrogen chloride scavenger (eg NH.sub.3) to feed ratios, reactor temperature and pressure may be adjusted to suit the particular solvent composition (eg transformer oil composition) being treated, particularly, in relation to its chlorine content. Deposition of NH.sub.4 Cl in the reactor effluent heat exchanger 105 is possible. However, reactor conditions (i.e. temperature and pressure and feed rate) are generally adjusted such that in catalytic reactor 109 NH.sub.3 formed or added to reactor 109 and HCl remain dissociated and in the gas phase. However when the reactor effluent leaves reactor 109 and as the reactor effluent is cooled, solid NH.sub.4 Cl deposits out of the gas phase with the deposition temperature dependent on the partial pressures of NH.sub.3 and HCl. While reactor pressure, H.sub.2 and hydrogen chloride scavenger (eg NH.sub.3) flowrates will typically be operated over a fairly narrow range, deposition temperature is primarily dependent on the chlorine content of the feed (which may vary considerably between individual solvents such as transformer oils). For example, a chlorine content of 19.1 ppmw is about equivalent to 32 ppmw PCB as hexachlorobiphenyl and the estimated deposition temperature is around 235.degree. C. It is important that for a given chlorine (or other halide) content in the feed solvent, values of temperature and pressure are chosen such that there is no deposition of ammonium chloride (or other ammonium halide) or other acid neutralisation product, on the catalyst. Such deposition would firstly reduce catalyst activity by blocking active sites and eventually cause physical blockage of the reactor itself. The outlet of reactor effluent exchanger 105 is maintained at around this temperature to avoid deposition in the absence of liquid water. Wash water is introduced downstream of exchanger 105 at a sufficient rate to ensure the existence of sufficient liquid water to wash the oil and dissolve the NH.sub.4 Cl. As feed chlorine content increases the temperature at which NH.sub.4 Cl deposition decreases requiring an increase in the exchanger 105 outlet temperature which in turn results in an increased wash water requirement and increased load on the high pressure vent condenser 103. Estimated sensitivity of deposition temperature to feed of deposition temperature to feed chlorine content is shown in FIG. 2. Some progressive fouling of reactor effluent heat exchanger 105 can be tolerated and detailed design should ensure that the unit can operate for the duration of processing the maximum transformer volumes without a need for cleaning. Removal of NH.sub.4 Cl deposits can most likely be normally carried out without disassembly at the completion of a run by allowing a reduced rate of oil at reduced H.sub.2 pressure to flow through the exchanger 105 at near reactor temperature. NH.sub.4 Cl could then be volatilised and subsequently removed in the wash water in the normal way. Processing objectives for the mobile treatment plant are focused on the following main areas: Selection of a design processing rate consistent with treating a broad range of transformer sizes, in terms of oil volume, with minimum transformer downtime and providing the ability to treat as high a proportion of the transformer oil inventory as possible onsite. Regeneration of transformer oils by hydrogenation of oxidation and other oil ageing related components and destruction of residual PCBs where transformers have previously contained these materials at some level during normal service, or have been cross contaminated during oil refining or topping up activities. Key regeneration objectives are the full recovery of the electrical properties of the mineral oil, high yield of recovered oil for return to service, elimination of PCBs, where present in the oil, to levels below those where the oil would be regarded as a scheduled waste if removed from service. Minimisation of treatment plant effluents and emissions overall, and constraint of emissions during on-site operations to carefully controlled discharge of low volume of combustion gas and treated waste water. Small volumes of waste oil and caustic solutions from gas cleaning operation are contained within the unit, while on-site and disposed of separately to appropriate facilities. In designing the process flowsheet for the plant depicted in FIG. 1, operating conditions and process performance have been based on experimental for processing of a particular sample of PCB contaminated transformer oil. Details of the feed oil, experimental process performance, derived plant performance parameters and target oil quality data are outlined below. Feed Oil Characteristics Characteristics for the feed oil used in experimental runs defining the design performance data are those of sample HT14-Feed and are as follows: Physical Properties and Composition 1. Boiling range as D-86 simulation based on GC analysis is given in Table BM1.1. TABLE BM1.1 ______________________________________ FEED OIL DISTILLATION RANGE PERCENT OFF (vol %) BOILING POINT ______________________________________ IBP 308.1 10 338.6 20 348.3 30 352.9 50 360.5 70 367.8 80 370.5 90 382.1 FBP 405.3 ______________________________________ 2. Oil Density = 870 kg/m.sup.3 @ 20.degree. C. 3. Composition: Sulphur content = 400 mg/kg Nitrogen content = 12.9 mg/L Chlorine content = 19.1 mg/kg. ______________________________________ Electrical and other properties considered key parameters in the specifications for transformer oils are shown in Table BM1.3 along with product oil analyses and target values. Process Conditions Optimised processing conditions were selected from a broad series of runs, and tested in the experimental rig. This optimised data as represented by sample HT16.3 has been taken as the design basis for the process and is presented below. Reactor Operating Conditions ______________________________________ Pressure = 3.5 MPag Temperature = 330.degree. C. Weight Hourly Space Velocity = 3.0 h.sup.-1 Hydrogen Consumption by Reaction = 2.389 .times. 10.sup.-2 kg H.sub.2 /kg feed oil Hydrogen at Reactor Inlet = 2.007 .times. 10.sup.-2 kg H.sub.2 /kg feed oil Ammonia at Reactor Inlet = 6.121 .times. 10.sup.-4 kg NH.sub.3 /kg feed oil Removal of Heteroatoms from Oil: Sulphur elimination = 91.24% Chlorine elimination = 99.68% Nitrogen elimination = 44.2% Product Oil Characterisics ______________________________________ Product oil boiling range is given as the bottom oil before vacuum degassing. The boiling range as a D-86 simulation from GC analysis data is given in Table BM1.2. TABLE BM1.2 ______________________________________ PRODUCT OIL BOILING RANGE (BEFORE DE-GASSING) PERCENT OFF BOILING POINT (vol %) (.degree. C.) ______________________________________ IBP 269.1 10 322.5 20 335.4 30 342.6 50 354.0 70 364.2 80 368.1 90 380.5 FBP 404.7 ______________________________________ Oil Composition: Sulphur content = 35 mg/kg Nitrogen content = 7.2 mg/L Chlorine content = 0.06 mg/kg ______________________________________ Total PCB content measured for 2 product oil samples from runs other than HT-16.3 (for reactor conditions 5.0 MPag, WHSV 1.0, 320.degree. C.) was less than 10 ppb in both samples. PCB destruction is therefore likely to be significantly greater than the measured chlorine elimination from the oil. ______________________________________ Oil yield after vacuum degassing = 99.57% on feed oil in experiment HT-16.3. Flow sheet oil yield after degassing = 99.23% feed oil Comparative Electrical Properties ______________________________________ Table BM1.3 shows the key insulating oil parameters appearing in specifications as measured for the feed and product oils along with indicative target values. Product oil electrical properties were measured after vacuum degassing at 0.7 mbar and 77.degree. C. TABLE BM1.3 __________________________________________________________________________ INSULATING OIL PROPERTIES FLASH INTERFACIAL ELECTRICAL POINT ACIDITY TENSION DDF RESISTIVITY STRENGTH SAMPLE (.degree. C.) (mg KOH/g) (mN/M) (mW/VAR) (Gohm .multidot. m) (kV) __________________________________________________________________________ Feed Oil HT14 155 0.06 24.1 73.2 4.5 44 Product Oil HT 16.3 142 0 47.2 0.2 6500 >71 Target New Oil >130 0.03 max 35 min 5 max 60 min 30 min Action Limits 0.2 20 100 10 __________________________________________________________________________ Results indicated for product oil based on the optimised experimental run HT-16.3 indicates that with respect to these key parameters the product oil meets the specifications set for new transformer oils. Some 26 runs were conducted in this series over a range of operating conditions. Twenty three runs met the target new oil specification with the other three failing by reduced flash point only. In these three runs reactor operating conditions included the highest temperature in conjunction with the lowest space velocities used in the trials, i.e. the most severe hydrogenation conditions in the series. Under these conditions the greater proportion of light ends produced results in an increase in volatile components remaining after vacuum distillation. The range of operating conditions covered in the trials is as follows: ______________________________________ Pressure range = 2-5 MPag Temperature range = 320-360.degree. C. WHSV = 1-3 hour.sup.-1 Feed chlorine content = 19.1-91 ppmw Product chlorine content = 0.06-0.54 ppmw ______________________________________ Control of reactor conditions around the currently identified optimum of 330.degree. C. at 3.5 MPag and WHSV of 3.0 hour.sup.-1 is readily achieved and could be expected to result in consistent product characteristics from a particular feed. |
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