Patent EA-000667-B1 (EA)
Title: Process and apparatus for the treatment of waste oils
Inventor: YU HESHUI
IPC: C10G51/02
Filed: 1997-01-24
Abstract: 1. A process for treating waste oil containing heavy hydrocarbons and contaminants, which comprises: raising a temperature of a feed mixture of fresh waste oil and a recycled non-volatile residue to a range of 400 degree C to 490 degree C under an excessive pressure of about 40 to 150 psi for a time period of 1 to 15 seconds sufficient to cause pyrolysis of said heavy hydrocarbons contained in the feed mixture, but insufficient to permit substantial undesired polymerization, oxidation and dehydrogenation reactions to take place in said feed mixture; cooling the resulting pyrolyzed waste oil mixture to a temperature in the range of 300 degree C to 455 degree C, and maintaining said temperature while allowing volatile components in the pyrolyzed waste oil mixture to evaporate, leaving a non-volatile residue containing said contaminants; condensing the evaporated volatile components to form a reclaimed oil product; and mixing the non-volatile residue with fresh waste oil to form more of said feed mixture and repeating said temperature raising, cooling, evaporation and mixing steps on a continuous basis, while continuing to condense volatile components evaporated from said pyrolyzed waste oil mixture. 2. A process according to claim 1 wherein, when a yield of said reclaimed oil product falls below a predetermined level, said temperature of said feed mixture is raised to promote deep cracking of said heavy hydrocarbons, and a resulting pyrolyzed waste oil mixture is then subjected to further cooling, evaporation, mixing and temperature raising steps. 3. A process according to claim 1 wherein, when contaminants in said pyrolyzed waste oil mixture increase to a predetermined level, said non-volatile residue containing said contaminants is heated to a temperature in the range of 470 degree C to 590 degree C, and is then brought to a temperature in the range of 440 degree C to 570 degree C, and is maintained at said temperature under a pressure of 21 kPa to 172 kPa to cause said residue to undergo a further pyrolysis and coking reaction creating further volatile components and a solid coke, whereupon said further volatile components are removed and condensed, and said solid coke is collected and discarded. 4. A process according to claim 1 wherein steam is introduced into said feed mixture before said temperature raising step is carried out, and wherein water is separated from said volatile components. 5. A process according to claim 1 wherein said feed mixture is subjected to a pressure in the range of 276 kPa to 1034 kPa as said temperature is raised. 6. A process according to claim 6 wherein the time period is 3 Co 10 seconds. 7. A process according to claim 1 wherein the resulting pyrolyzed waste oil mixture is cooled to a temperature in the range of 300 to 425 degree C. 8. A process according to claim 1 wherein the resulting pyrolyzed waste oil mixture is cooled to a temperature in the range of 300 to 375 degree C. 9. Apparatus for treating waste oil containing heavy hydrocarbons and contaminants, which comprises: a heating unit for raising a temperature of a feed mixture of fresh waste oil and a recycled non-volatile residue to a range of 400 to 490 degree C for a time sufficient to cause pyrolysis of said heavy hydrocarbons contained in the feed mixture, but insufficient to permit substantial undesired polymerization, oxidation and dehydrogenation reactions to take place in said feed mixture; a container for receiving the resulting pyrolyzed waste oil mixture and for holding and maintaining said pyrolyzed waste oil mixture at a temperature in the range of 300 degree C to 455 degree C, while allowing volatile components in the pyrolyzed waste oil mixture to evaporate, leaving a non-volatile residue containing said contaminants; a condenser for condensing the evaporated volatile components to form a reclaimed oil product; and pumping equipment and piping for mixing the nonvolatile residue from said container with fresh waste oil to form more of said feed mixture, for continuously recirculating said feed mixture through said heating unit to said container, and for conveying said volatile components from said container to said condenser. 10. An apparatus for treating waste oil according to claim 9 wherein said heating unit contains at least one heating tube. 11. An apparatus for treating waste oil according to claim 10 wherein said at least one heating tube is straight. 12. An apparatus for treating waste oil according to claim 10 wherein said at least one heating tube is set in said heating unit in an orientation selected from the group consisting of vertical, oblique and horizontal. 13. An apparatus for treating waste oil according to claim 9 having two said containers and including pipes and valves allowing said containers to be used alternately. 14. An apparatus for treating waste oil according to claim 13 wherein said two containers are substantially identical.