Union Carbide Corporation

Gilbert R Atwood

Alexander J Kosseim

Joseph E Sokolik, Jr

David Arthur Dunnery

Method for replacing a coolant containing PCB in electrical induction apparatus having a tank containing the PCB-containing coolant, an electrical winding and porous solid cellulosic electrical insulation immersed in, and impregnated with, the PBC-containing coolant with a substantially PCB-free permanent coolant to convert said electrical apparatus into one in which the rate of elution of PCB into the PCB-free coolant is below the maximum allowable rate of elution into the coolant of an electrical apparatus rated as non-PCB comprising steps of: (a) draining the PCB-containing coolant from said tank; (b) filling the tank with an interim dielectric cooling liquid; (c) electrically operating the apparatus; (d) thereafter draining the interim dielectric cooling liquid containing the eluted PCB from the tank; (e) repeating the cycle of steps (b), (c) and (d) a sufficient number of times until the PCB elution rate does not exceed the rate of 50 ppm PCB based on the weight of the permanent coolant after 90 days of electrical operation; and (f) filling the tank with a substantially PCB-free permanent coolant.

Method for replacing PCB-containing coolants in electrical induction

Method for replacing a coolant containing PCB in electrical induction apparatus having a tank containing the PCB-containing coolant, an electrical winding and porous solid cellulosic electrical insulation immersed in, and impregnated with, the PCB-containing coolant with a substantially PCB-free permanent coolant to convert said electrical apparatus into one in which the rate of elution of PCB into the PCB-free coolant is below the maximum allowable rate of elution into the coolant of an electrical apparatus rated as non-PCB comprising steps of: (a) draining the PCB-containing coolant from said tank; (b) filling the tank with an interim dielectric cooling liquid; (c) electrically operating the apparatus; (d) thereafter draining the interim dielectric cooling liquid containing the eluted PCB from the tank; (e) repeating the cycle of steps (b), (c) and (d) a sufficient number of times until the PCB elution rate does not exceed the rate of 50 ppm PCB based on the weight of the permanent coolant after 90 days of electrical operation; and (f) filling the tank with a substantially PCB-free permanent coolant selected from the group consisting of high boiling, high viscosity, silicone oils, synthetic ester fluids, poly-alpha-olefin oils and hydrocarbon oils.

Method for replacing PCB containing coolants in electrical induction

Method of replacing a PCB-containing coolant in electrical induction apparatus having a vessel containing said PCB-containing coolant, an electrical winding and porous solid cellulosic electrical insulation immersed in, and impregnated with, said PCB-containing coolant with a substantially PCB-free high boiling dielectric permanent coolant into which any residual PCBs elute at no greater than a selected target rate comprising steps of (a) draining the PCB-containing coolant from the vessel, (b) filling the vessel with an interim dielectric coolant, (c) electrically operating the apparatus, (d) removing interim coolant containing eluted PCB, (e) repeating steps (b), (c) and (d) a sufficient number of times until the PCB elution rate does not exceed 5 times a selected target rate, (f) filling the vessel with PCB-free high boiling dielectric silicone oil as coolant, (g) electrically operating the apparatus, (h) thereafter removing the silicone oil coolant containing eluted PCB, (i) repeating steps (f), (g) and (h) a sufficient number of times until the PCB elution rate into the silicone oil is less than the selected target rate, and refilling the vessel with a substantially PCB-free dielectric cooling liquid.

A regenerable process for scrubbing SO.sub.2 from effluent gases using an aqueous alkanolamine and the corresponding sulfite as the solvent, such amine having a boiling point below about 250.degree. C. at one atmosphere pressure and wherein the alkanolamine solutions containing heat stable salts (HSS) is regenerated by alkali addition, crystallization and vacuum distillation of the amine.

Regenerable process for the selective removal of sulfur dioxide from

Method for scrubbing SO.sub.2 from effluent gases using aqueous monoethanolamine and the corresponding sulfite as the solvent. The method is especially useful where the effluent gases contain an abundance of CO.sub.2 relative to SO.sub.2.

Process for the selective removal of sulfur dioxide from effluent gases

Improvement in processes for the selective removal of sulfur dioxide with respect to carbon dioxide from a gas mixture containing same wherein the gas mixture is contacted with an aqueous absorbent solution, such as alkanolamine, alkali metal hydroxide, ammonium hydroxide or sulfites thereof, to remove sulfur dioxide from the gas mixture and form a SO.sub.2 -rich aqueous absorbent solution which is moved to a stripping zone where sulfur dioxide is driven off to form a SO.sub.2 -depleted aqueous absorbent solution which is recycled and re-contacted with the gas mixture, the improvement comprising removing sulfur oxyanions of heat stable salts which accumulate in the aqueous absorbent solution by contacting a portion of it with an anion exchange resin having hydroxyl anions displaceable by the heat stable sulfur oxyanions whereby the hydroxyl anions of the resin are replaced by the heat stable divalent sulfur oxyanions which are thus taken out of the solution. The anion exchange resin preferably is a strong base anion exchange resin which can be regenerated by contacting it with aqueous sodium hydroxide to replace the heat stable sulfur oxyanions on said resin with hydroxyl anions.

Process for removing SO.sub.2 from effluent gases and for removing heat

Improvement in processes for the selective removal of sulfur dioxide with respect to carbon dioxide from a gas mixture containing same wherein the gas mixture is contacted with an aqueous absorbent solution, such as an alkanolamine, an alkali metal or ammonium hydroxide, or sulfites thereof, to remove sulfur dioxide from the gas mixture and form a SO.sub.2 -rich aqueous absorbent solution which is moved to a stripping zone where sulfur dioxide is driven off to form a SO.sub.2 -depleted aqueous absorbent solution which is recycled and re-contacted with the gas mixture, the improvement comprising removing sulfur oxyanions of heat stable salts which accumulate in the aqueous absorbent solution by contacting it with an anion exchange resin having bisulfite anions displaceable by the heat stable sulfur oxyanions whereby the bisulfite anions of the resin are replaced by the heat stable divalent sulfur oxyanions which are thus taken out of the solution. The anion exchange resin preferably is a weak base anion exchange resin which can be regenerated by contacting it with aqueous ammonium hydroxide to replace the heat stable sulfur oxyanions on said resin with hydroxyl anions and thereafter contacting the resin with aqueous-sulfur dioxide to replace the hydroxyl anions with bisulfite anions.

Process for the recovery of sulfur from gas streams containing hydrogen sulfide comprising the steps of reacting a portion of the hydrogen sulfide with sulfur dioxide in a Claus reaction to form sulfur, removing the sulfur, incinerating the residual hydrogen sulfide in the resulting gas stream to sulfur dioxide, absorbing the sulfur dioxide in the incinerated gas stream in an aqueous absorbent solution, stripping the sulfur dioxide from the aqueous absorbent solution, recycling the stripped sulfur dioxide for reaction with succeeding portions of hydrogen sulfide in the incoming gas stream, re-contacting the stripped aqueous absorbent solution with succeeding portions of the incinerated gas stream to absorb additional sulfur dioxide, regenerating a portion of the aqueous absorbent solution to remove heat stable sulfur oxyanions therefrom by contacting said solution with an anion exchange resin and re-contacting the regenerated aqueous absorbent solution with said incinerated gas stream to absorb additional sulfur dioxide.

Growing community of inventors

Briarcliff Manor, NY, United States of America

Gilbert R Atwood