Claims
- 1. A process for converting acid sludge to asphalt comprising:
- raising the pH of said acid sludge to a target pH in the range from 3 to 7 by mixing a pH elevating agent including at least water with said acid sludge, said target pH being high enough that said acid sludge does not become sandy and un-meltable at temperatures from approximately from 70.degree. F. up to approximately 275.degree. C., thereby creating a mixture comprising a layer of mostly water and a layer of intermediate sludge;
- separating said intermediate sludge from substantially all said water thereby creating a body of intermediate sludge with some water content;
- performing a low temperature heating step by heating said intermediate sludge to a temperature between 100.degree. C. to 275.degree. C. for a time long enough to remove the remaining water content thereby creating soft asphalt.
- 2. The process of claim 1 wherein said step of raising said pH comprises the steps of:
- placing the acid sludge in an acid resistant tank;
- adding water in the tank in the proportion of 5-10 parts water to one part acid sludge to form a mixture of water and acid sludge;
- mixing the mixture thoroughly;
- measuring the pH;
- if the pH is not high enough, removing the water and adding fresh water;
- mixing the mixture again and re-measuring the pH; and
- repeating the foregoing process until the pH rises to approximately 3-7.
- 3. The process of claim 1 wherein said step of raising the pH said acid sludge is accomplished by adding in addition to water either a pure solid pH elevating agent selected from the group consisting of caustic soda, lime or soda ash or by dispersing said solid pH elevating agent in a liquid solution and adding the solution to the acid sludge, and then agitating the resulting mixture.
- 4. The process of claim 2 wherein said mixture of acid sludge and pH elevating agent are heated during mixing to lower the viscosity of the mixture.
- 5. The process of claim 1 wherein said low temperature heating step further comprises the steps of:
- heating said soft asphalt to a temperature between 200.degree. C. and 275.degree. C., preferably 230.degree. C. and bubbling air through the mixture for between 10-20 hours to generate hard oxidized asphalt.
- 6. The process of claim 2 wherein said low temperature heating step further comprises the steps of:
- heating said soft asphalt to a temperature between 200.degree. C. and 275.degree. C., preferably 230.degree. C. and bubbling air through the mixture for between 10-20 hours to generate hard oxidized asphalt.
- 7. The process of claim 4 wherein said low temperature heating step further comprises the steps of:
- heating said soft asphalt to a temperature between 200.degree. C. and 275.degree. C., preferably 230.degree. C. and bubbling air through the mixture for between 10-20 hours to generate hard, oxidized asphalt.
- 8. A process for converting acid sludge to asphalt comprising:
- raising the pH of said acid sludge to a target pH in the range from 3 to 7 by mixing a pH elevating agent including at least water with said acid sludge, said target pH being high enough that said acid sludge does not become sandy and un-meltable at temperatures from approximately 25.degree. C. up to approximately 275.degree. C., thereby creating a mixture comprising a layer of mostly water and a layer of intermediate sludge;
- separating said intermediate sludge from substantially all said water thereby creating a body of intermediate sludge with some remaining water content;
- performing a low temperature heating step by heating said intermediate sludge to a temperature between 100.degree. C. to 275.degree. C. for a time long enough to remove the remaining water content thereby creating soft asphalt;
- and wherein said low temperature heating step further comprises the step of heating said soft asphalt to a temperature between 200.degree. C. and 275.degree. C., preferably 230.degree. C. and bubbling air through the mixture at a selected flow rate for a selected time where said selected flow rate and said selected time are chosen to obtain a desired penetration number, between 6 and 100.
- 9. A process comprising the steps of:
- (1) providing used oil having impurities including one or more of, water, chlorinated compounds, carbonaceous compounds, metals, oxidizable components and light ends and additives including dispersant additives therein,
- (2) generating a quantity of dehydrated oil by performing a high temperature heating step by heating the oil to a temperature greater than about 650 degrees Fahrenheit and less than or equal to 1000 degrees Fahrenheit for a time sufficient to dissociate at least said dispersant additives and sufficient to remove water, light ends and chlorinated compounds having boiling points below 650.degree. F.,
- (3) cooling the oil,
- (4) adding a sufficient amount of acid or other oxidizing agent of a concentration and amount adequate to oxidize substantially all carbonaceous materials, metals and other oxidizable impurities and other undesired components in said used oil so as to generate oxidized products and cause the oxidized products to settle out of solution as acid sludge within one to three days, and preferably within 12-24 hours, so as to create a resulting mixture comprising a layer of acid sludge and a layer of oil which is substantially free of acid-sludge,
- (5) after substantially all acid sludge has settled out of solution, separating the acid sludge from the substantially acid-sludge-free oil,
- (6) adding a polishing agent to said acid-sludge-free oil, and steam sparging said acid-sludge-free oil to deodorize it, lighten the color thereof and raise the pH to a neutral value;
- (7) filtering said acid-sludge-free oil to remove spent polishing agent to create re-refined lubricating oil;
- (8) raising the pH of said acid sludge to a target pH in the range from 3 to 7 by mixing a pH elevating agent including at least water with said acid sludge, said target pH being high enough that said acid sludge does not become sandy and un-meltable at temperatures from approximately 70.degree. F. up to approximately 275.degree. C., thereby creating a mixture comprising a layer of mostly water and a layer of intermediate sludge;
- (9) separating said intermediate sludge from substantially all said water thereby creating a body of intermediate sludge with some remaining water content;
- (10) performing a low temperature heating step by heating said intermediate sludge to a temperature between 100.degree. C. to 275.degree. C. for a time long enough to remove the remaining water content thereby creating soft asphalt.
- 10. The process of claim 8 further comprising the steps of creating the acid sludge according to the following process:
- (1) providing used oil having impurities including one or more of water, chlorinated compounds, carbonaceous compounds, metals, oxidizable components and light ends and additives including dispersant additives therein,
- (2) generating a quantity Of dehydrated oil by performing a high temperature heating step comprising heating the oil to a temperature greater than 650 degrees Fahrenheit and less than or equal to 1000 degrees Fahrenheit for a time sufficient to dissociate at least said additives and to remove water and light ends and chlorinated compounds having boiling points below 650.degree. F.,
- (3) cooling the oil,
- (4) adding a sufficient amount of acid or other oxidizing agent of a concentration and amount adequate to oxidize substantially all carbonaceous materials, metals and other oxidizable impurities and other undesired components in said used oil to generate oxidized products and cause the oxidized products to settle out of solution as acid sludge within one to three days, and preferably within 12-24 hours, so as to create a resulting mixture comprising a layer of acid sludge and a layer of substantially acid-sludge-free oil,
- (5) separating the acid sludge from the substantially acid-sludge-free oil,
- (6) providing said acid sludge to said process for converting acid sludge to asphalt products, and
- (7) adding a polishing agent to said acid-sludge-free oil, and steam sparging said acid-sludge-free oil to deodorize it, lighten the color thereof and raise the pH to a neutral value; and
- (8) filtering said acid-sludge-free oil to remove spent polishing agent to create re-refined lubricating oil.
- 11. The process of claim 9 wherein said high temperature heating step further comprises heating said used oil in an enclosed tank and applying vacuum to said enclosed tank during said heating in a manner so as to draw off vapors outgassing from said used oil, said vapors including said light ends, said vapors being drawn by said vacuum through a heat exchanger condenser so as to cool and condense said vapors and collecting said condensed vapors.
- 12. The process of claim 9 wherein said high temperature heating step further comprises the step of steam sparging the used oil being heated during the heating process.
- 13. The process of claim 10 wherein said high temperature heating step further comprises the step of steam sparging the used oil during said high temperature heating step and applying vacuum to the tank in which said used oil is being heated during said high temperature heating step so as to draw off vapors outgassing from said heated used oil into a heat exchanger condenser where the vapors are cooled and condensed for collection.
- 14. The process of claim 9 wherein said high temperature heating step further comprises heating said used oil in an enclosed tank and applying vacuum to said enclosed tank during said high temperature heating in a manner so as to draw off vapors outgassing from said used oil through a heat exchanger so as to cool and condense said vapors and collecting said condensed vapors.
- 15. The process of claim 9 wherein said high temperature heating step further comprises the step of steam sparging the used oil being heated during said high temperature heating step and further comprising heating said used oil during said high temperature heating step in an enclosed tank and applying vacuum to said enclosed tank during said heating of said high temperature heating step in a manner so as to draw off vapors outgassing from said used oil through a heat exchanger so as to cool and condense said vapors and collecting said condensed vapors.
- 16. The process of claim 1 further comprising the steps of creating the acid sludge according to the following process:
- (1) providing used oil having impurities including one or more of, water, chlorinated compounds, carbonaceous compounds, metals, oxidizable components and light ends and additives including dispersant additives therein,
- (2) performing a high temperature heating step comprising heating the oil to a temperature which is high enough and for a time sufficiently long to dissociate at least said dispersant additives thereby allowing more rapid precipitation of acid sludge later when acid is added to the oil after, said high temperature heating step also simultaneously removing said water, light ends and chlorinated compounds having boiling points below the temperature to which said used oil is heated, said high temperature heating step raising the temperature of said used oil to at least 150 degrees Centigrade,
- (3) cooling the oil,
- (4) adding a sufficient amount of acid or other oxidizing agent of a concentration and amount adequate to oxidize substantially all said carbonaceous materials, metals and other oxidizable impurities and other undesired components in said used oil and cause the oxidized products to settle out of solution as acid sludge within one to three days, and preferably within 12-24 hours, so as to create a resulting mixture comprising a layer of acid sludge and a layer of substantially acid-sludge free oil,
- (5) after substantially all acid sludge has settled out of solution, separating the acid sludge from the substantially acid-sludge-free oil,
- (6) providing said acid sludge to said process for converting acid sludge to asphalt products, and
- (7) adding a polishing agent to said substantially acid-sludge-free oil, and steam sparging said Substantially acid-sludge-free oil to deodorize it, lighten the color thereof and raise the pH to a neutral value; and
- (8) filtering said substantially acid-sludge-free oil to remove spent polishing agent to create re-refined lubricating oil.
- 17. The process of claim 14 wherein said high temperature heating step further comprises the step of bubbling inert gas through the used oil being heated during said high temperature heating step.
- 18. The process of claim 16 wherein said high temperature heating step further comprises the step of bubbling inert gas through the used oil being heated during the high temperature heating step and wherein said high temperature heating step further comprises the step of steam sparging the used oil being heated during said high temperature heating step.
- 19. The process of claim 11 further comprising the step of monitoring the temperature of vapors inside said heat exchanger condenser and collecting vapors that condense at temperatures greater than approximately 350.degree. F. in a first collection tank for recycling as fuel oil and collecting vapors that condense at a temperature less than approximately 350.degree. F. in a second collection tank for disposal.
- 20. The process of claim 13 further comprising the step of monitoring the temperature of vapors inside said condenser and collecting vapors that condense at temperatures greater than approximately 350.degree. F. in a first collection tank for recycling as fuel oil and collecting vapors that condense at a temperature less than approximately 350.degree. F. in a second collection tank for disposal.
- 21. The process of claim 10 wherein said step of adding acid comprises the step of mixing a stream of dehydrated oil resulting from said high temperature heating step with a stream of acid in a proportionate pump to establish a proportion of 3-15% by volume of acid to dehydrated oil and mixing said acid stream and dehydrated oil in an in-line mixer, and wherein said step of separating said acid sludge from said acid-sludge-free oil is accomplished in a centrifuge.
- 22. The process of claim 1 further comprising the steps of creating the acid sludge according to the following process:
- (1) providing used oil having impurities including one or more of water, chlorinated compounds, carbonaceous compounds, metals, oxidizable components and light ends and additives including dispersant additives therein,
- (2) generating a quantity Of dehydrated oil by performing a high temperature heating step comprising heating the oil to a temperature greater than 650 degrees Fahrenheit and less than or equal to 1000 degrees Fahrenheit for a time sufficient to dissociate at least said dispersant additives and sufficient to remove water, light ends and chlorinated compounds having boiling points below 650.degree. F.,
- (3) cooling the oil,
- (4) adding a sufficient amount of acid or other oxidizing agent of a concentration and amount adequate to oxidize substantially all said carbonaceous compounds, metals and other oxidizable impurities and other undesired components in said used oil and cause the oxidized products to settle out of solution as acid sludge within one to three days, and preferably within 12-24 hours, so as to create a resulting mixture comprising a layer of acid sludge and a layer of substantially acid-sludge free oil,
- (5) separating the acid sludge from the substantially acid-sludge-free oil,
- (6) providing said acid sludge to said process for converting acid sludge to asphalt products, and
- (7) adding a polishing agent to said substantially acid-sludge-free oil, and steam sparging said substantially acid-sludge-free oil to deodorize it, lighten the color thereof and raise the pH to a neutral value; and
- (8) filtering said Substantially acid-sludge-free oil to remove spent polishing agent to create re-refined lubricating oil,
- and wherein said step of adding acid comprises the step of mixing a stream of dehydrated oil resulting from said high temperature heating step with a stream of acid in a proportionate pump to establish a proportion of 3-15% by volume of acid to dehydrated oil and mixing said acid stream and dehydrated oil in an in-line mixer, and wherein said step of separating said acid sludge from said substantially acid-sludge-free oil is accomplished in a centrifuge.
- 23. The process of claim 1 further comprising the step adding an additive to said soft asphalt, said additive selected from the group consisting of virgin asphalt, rubber or rubber compounds, resins or polymers to increase the cohesion of the soft asphalt, solvents suitable to produce cut back asphalt and water and emulsifier to produce emulsified asphalt.
- 24. The process of claim 8 further comprising the step adding an additive to said soft asphalt before conversion thereof to hard asphalt, said additive selected from the group consisting of virgin asphalt, rubber or rubber compounds, resins to increase the cohesion of the soft asphalt, solvents suitable to produce cut back asphalt and water and emulsifier to produce emulsified asphalt.
- 25. The process of claim 9 wherein said high temperature heating step comprises heating the oil to a temperature in the range from a temperature greater than 700.degree. F. to some temperature preferably less than or equal to 750.degree. F., and wherein the step of adding an oxidizing agent comprises the step of adding sulfuric acid having a concentration of from approximately 80-98 weight %, and adding a volume of sulfuric acid generally comprising 3-15% of the volume of dehydrated oil and, preferably, 5-10% by volume, and wherein the step of adding a polishing agent comprises the step of adding an agent having large pores and large surface area per particle selected from the group consisting of clay, bleaching earth, activated carbon or bauxite to adsorb oxidized particles and particles that color the oil and deodorize, lighten the color and neutralize the acidic nature of the re-refined oil.
- 26. The process of claim 10 wherein said high temperature heating step comprises heating the oil to a temperature in the range from a temperature greater than 700.degree. F. to some temperature preferably less than or equal to 750.degree. F., and wherein the step of adding an oxidizing agent comprises the step of adding sulfuric acid having a concentration of from approximately 80-98 weight %, and adding a volume of sulfuric acid generally comprising 3-15% of the volume of dehydrated oil and, preferably, 5-10% by volume, and wherein the step of adding a polishing agent comprises the step of adding an agent having large pores and large surface area per particle selected from the group consisting of clay, bleaching earth, activated carbon or bauxite to adsorb oxidized particles and particles that color the oil and deodorize, lighten the color and neutralize the acidic nature of the re-refined oil.
- 27. The process of claim 9 wherein the step of adding a polishing agent comprises the step of adding a sufficient amount of polishing agent having large pores and large surface area per particle selected from the group consisting of clay, bleaching earth, activated carbon or bauxite so as to absorb oxidized particles and particles that color the oil while steam sparging the oil being treated with the polishing agent so as to deodorize and neutralize the acidic nature of the re-refined oil and lighten the color thereof so as to be from 2.0-5.0, and, preferably, from 2.0-3.0 measured according to the color scale of the American Society for Testing and Materials, method D1500.
- 28. The process of claim 1 wherein the step of raising the pH comprises the step of adding a liquid having a pH of from about 3 to 14, and further comprising the step of washing said acid sludge after raising the pH thereof so as to remove salts which result therein from the reaction of the pH elevating agent with said acid sludge.
- 29. The process of claim 1 further comprising the step of heating and agitating the acid sludge while the pH elevating agent is in contact therewith but before separation of said layer of water from said intermediate sludge.
- 30. The process of claim 9 further comprising the step of agitating the mixture after addition of said oxidizing agent.
- 31. The process of claim 10 further comprising the step of agitating the mixture after addition of said oxidizing agent.
- 32. The process of claim 9 further comprising the step of agitating the cooled oil during addition of said polishing agent.
- 33. The process of claim 10 further comprising the step of agitating the cooled oil during addition of said polishing agent.
- 34. The process of claim 11 further comprising the steps of separating water and other undesirable components from said light ends in said vapors being condensed in said heat exchanger condenser and using the light ends as fuel for a heater unit used to carry out said high temperature heating step.
- 35. The process of claim 1 further comprising the steps of creating the acid sludge according to the following process:
- (1) providing used oil having impurities including one or more of water, chlorinated compounds, carbonaceous compounds, metals, oxidizable components and light ends and additives including dispersant additives therein,
- (2) performing a high temperature heating step comprising heating the oil to a temperature greater than 700 degrees Fahrenheit and less than or equal to 1000 degrees Fahrenheit, preferably between 726.degree. F. and 750.degree. F., for a time sufficient to dissociate at least said dispersant additives and to remove said water light ends and chlorinated compounds having boiling points below 700.degree. F.,
- (3) cooling the oil,
- (4) adding a sufficient amount of acid or other oxidizing agent of a concentration and amount adequate to oxidize substantially all carbonaceous compounds, metals and other oxidizable impurities and other undesired components in said used oil thereby forming oxidized products and causing the oxidized products to settle out of solution as acid sludge within one to three days, and preferably within 12-24 hours, so as to create a resulting mixture comprising a layer of acid sludge and a layer of oil which is substantially free of acid-sludge,
- (5) separating the acid sludge using a centrifuge so as to generate a volume of substantially acid-sludge-free oil and a volume of acid sludge,
- (6) providing said acid sludge to said process for converting acid sludge to asphalt products, and
- (7) adjusting the pH of the substantially acid-sludge-free oil by adding a pH elevating agent to generate heavy fuel oil which is substantially free of heavy metals, chlorinated compounds, sulfur and carbonaceous materials.
- 36. The process of claim 8 further comprising the steps of creating the acid sludge according to the following process:
- (1) providing used oil having impurities including one or more of water, chlorinated compounds, carbonaceous compounds, metals, oxidizable components and light ends and additives including dispersant additives therein,
- (2) heating the oil to a temperature greater than 700 degrees Fahrenheit and less than or equal to 1000 degrees Fahrenheit, preferably between 726.degree. F. and 750.degree. F., for a time sufficient to dissociate at least said dispersant additives and to remove water, light ends and chlorinated compounds having boiling points below 700.degree. F.,
- (3) cooling the oil,
- (4) adding a sufficient amount of acid or other oxidizing agent of a concentration and amount adequate to oxidize substantially all carbonaceous compounds, metals and other oxidizable impurities and other undesired components in said used oil thereby forming oxidized products and causing the oxidized products to settle out of solution as acid sludge within one to three days, and preferably within 12-24 hours, so as to create a resulting mixture comprising a layer of acid sludge and a layer of oil which is substantially free of acid-sludge,
- (5) separating the acid sludge using a centrifuge so as to generate a volume of substantially acid-sludge-free oil and a volume of acid sludge,
- (6) providing said acid sludge to said process for converting acid sludge to asphalt products, and
- (7) adjusting the pH of the substantially acid-sludge-free oil by adding a pH elevating agent to generate heavy fuel oil which is substantially free of heavy metals, chlorinated compounds, sulfur and carbonaceous compounds.
- 37. The process of claim 35 wherein said high temperature heating step further comprises heating said used oil in an enclosed tank and applying vacuum to said enclosed tank during said heating in a manner so as to draw off vapors outgassing from said used oil through a heat exchanger/condenser so as to cool and condense said vapors and collecting said condensed vapors, and further comprising the step of monitoring the temperature of vapors inside said condenser and collecting vapors that condense at temperatures greater than approximately 350.degree. F. in a first collection tank for recycling as fuel oil and collecting vapors that condense at a temperature less than approximately 350.degree. F. in a second collection tank for disposal.
- 38. The process of claim 36 wherein said high temperature heating step further comprises heating said used oil in an enclosed tank and applying vacuum to said enclosed tank during said heating in a manner so as to draw off vapors outgassing from said used oil through a heat exchanger/condenser so as to cool and condense said vapors and collecting said condensed vapors, and further comprising the step of monitoring the temperature of vapors inside said condenser and collecting vapors that condense at temperatures greater than approximately 350.degree. F. in a first collection tank for recycling as fuel oil and collecting vapors that condense at a temperature less than approximately 350.degree. F. in a second collection tank for disposal.
- 39. The process of claim 35 wherein said high temperature heating step further comprises heating said used oil in an enclosed tank and applying vacuum to said enclosed tank during said heating in a manner so as to draw off vapors outgassing from said used oil, said vapors including said light ends, said vacuum drawing said vapors through a heat exchanger/condenser so as to cool and condense said vapors and collecting said condensed vapors as a liquid including water and light ends, and further comprising the step of separating the water from the light ends in said liquid generated by condensing said vapors and heating said light ends to a temperature of 100.degree. C. to 150.degree. C. to remove any chlorinated compounds therein so as to leave chlorine-free, light fuel oil, and further comprising the step of oxidizing any sulfur compounds in said chlorine-free, light fuel oil by addition of an oxidizing agent thereto to cause any sulfur compounds to precipitate as acid sludge to leave chlorine-free, substantially sulfur-free, light fuel oil, and further comprising the step of conveying said acid sludge to the input point of said process of converting acid sludge to asphalt, and further comprising the step of adjusting the pH of said chlorine-free, substantially sulfur-free, light fuel oil to a neutral value by addition of a pH elevating agent selected from the group consisting of amine compound and caustic solution and removing any resulting solids or water from the resulting neutral pH, sulfur-free, chlorinated-compound-free light fuel oil.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This is a continuation-in-part of a U.S. patent application, Ser. No. 08/071,775, filed Jun. 4, 1993 (APO-001.1P) entitled "AN IMPROVED PROCESS FOR RE-REFINING USED OIL" (now U.S. Pat. No. 5,514,272 , which was a continuation-in-part of a U.S. patent application entitled "AN IMPROVED PROCESS FOR RE-REFINING USED OIL", Ser. No. 07/879,634, filed May 7, 1992 (now abandoned), and is also a continuation of a U.S. patent application, Ser. No. 07/879,642, filed May 7,1992 entitled "A PROCESS FOR CONVERTING ACID SLUDGE INTO INTERMEDIATE SLUDGE" (which issued as U.S. Pat. No. 5,288,392 on Feb. 22, 1994).
US Referenced Citations (6)
Non-Patent Literature Citations (8)
Entry |
Kirk-Othmer, "Asphalt" Encyclopedia of Chemical Technology, Third Edition, vol. 3, Antibiotics (Phenazines) to Bleaching Agents, pp. 299-302 (no date). |
Interline Resources Corporation, "Interline Re-refining Process", Executive Summary, Oct. 1993. |
M. L. Whisman, J. W. Goetzinger, and F. O. Cotton, "Petroleum Refinery Engineering", Report of Investigations 7884, Waste Lubricating Oil Research, pp. 228 (1974). (no month). |
W. L. Nelson, "Chemical Treatments", Petroleum Refinery Engineering, Fourth Edition, pp. 261/292-297 (1958). (no month). |
English Transaction of Patenschrift, DE 42 05 885 C1, for Bernard Meinken (Mar. 1993). |
English Translation of Offenlegungsschrift, DE 42 05 884 A1, for Bernard Meinken (Sep. 1993). |
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Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
71775 |
Jun 1993 |
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Parent |
879634 |
May 1992 |
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