Solvent Extraction Technology for Used Oil Treatment Solvent Extraction Technology for Used Oil Treatment FINAL REPORT Prepared for Recycling Technology Assistance Partnership (ReTAP) A program of the Clean Washington Center, a division of the Pacific Northwest Economic Region (PNWER) 2200 Alaskan Way, Suite 460 Seattle, Washington 98121 December 1995 Prepared by AERCO, Inc., P.S. 18503 - 71st Avenue West Lynnwood, Washington 98037 This recycled paper is recyclable Copyright ©1995 by Clean Washington Center Report No. O-95-1 SOLVENT EXTRACTION TECHNOLOGY FOR USED OIL TREATMENT FINAL REPORT TABLE OF CONTENTS Page TABLE OF CONTENTS ................................................................................... i ABSTRACT....................................................................................................... 1 1.0 PROJECT OVERVIEW ............................................................................ 2 1.1 THE USED OIL INDUSTRY............................................................... 2 1.2 SELECTION OF THE SOLVENT EXTRACTION TECHNOLOGY... 4 1.3 THE SOLVENT EXTRACTION TECHNOLOGY .............................. 5 1.4 PROJECT OBJECTIVES ..................................................................... 6 2.0 LITERATURE SEARCH FINDINGS....................................................... 8 3.0 PILOT PLANT DESIGN ........................................................................... 9 3.1 DESIGN ASSUMPTIONS ................................................................... 9 3.2 DESIGN DOCUMENTS .................................................................... 11 4.0 FURTHER DEVELOPMENT OF TECHNOLOGY.............................. 16 4.1 PILOT SCALE ................................................................................... 16 4.2 FULL SCALE..................................................................................... 17 4.3 SUMMARY........................................................................................ 17 5.0 ACKNOWLEDGMENTS........................................................................ 19 6.0 REFERENCES......................................................................................... 20 LIST OF FIGURES Figure 1 - Simplified Process Flow Diagram .................................................... 6 Figure 2 - Process Flow Diagram .................................................................... 14 Figure 3 - Piping And Instrumentation Diagram........................................... 15 Figure 4 - Appendix A, Equipment List ......................................................... 22 i ABSTRACT Solvent extraction, an innovative adaptation of existing crude oil refining technology, is being studied for its potential to upgrade used oils produced by small-scale oil treatment facilities. This report presents the design for a pilot-scale treatment plant using solvent extraction technology to produce an improved fuel product. The solvent treatment technology presented in this report, either alone or in combination with existing used oil dehydration facilities, has the potential to significantly reduce the impurities in the product oil currently produced by used oil processing or treatment companies. This product oil could be used for higher value fuels without attempting to meet all the stringent specifications and requirements that would accompany the production of lubrication stocks. The technology has already been used successfully in Europe as a unit process on a larger scale to produce lubrication stock from used oil. The technology also has the potential to produce a higher quality fuel than the heavy “cutter stock” currently being produced for blending into marine diesel fuel. This report presents the design and supporting documents for the construction of a pilot scale solvent treatment plant. Observations and discussion regarding the project and the design assumptions are presented along with the design. The objectives for the design phase of the project were as follows: • Determine key process parameters to guide the design of the pilot plant; • Design a pilot scale plant that produces sufficient quantities of used oil for product testing. This report also recommends the future construction of a pilot scale solvent treatment plant by interested parties to allow refinement of the design, testing with a wide variety of used oil streams, treatment cost evaluation, and production of sufficient quantities of product oils and asphalt bottoms to allow acceptance testing with customers of these products. 1 1.0 PROJECT OVERVIEW Solvent extraction, an innovative adaptation of existing crude oil refining technology, is being studied for its potential to upgrade used oils produced by small-scale oil treatment facilities. This report presents the design for a pilot-scale treatment plant using solvent extraction technology to produce an improved fuel product. 1.1 THE USED OIL INDUSTRY Used oils are by-products of oil use in vehicles and machinery. Lubricating oils must be replaced on a regular basis in all operating equipment due to contamination from dirt, water, salts, metals, incomplete products of combustion, antifreeze, or other materials. Additives to lubricating oils may also break down under use, adding contamination. Once replaced by new lubricants, used oil becomes a significant management challenge. Without access to suitable recycling or waste-to-energy options, used oil tends to be disposed in ways that can degrade the environment: as “road oil” for dust control; illegally dumped into waterways; or disposed on land or in landfills where groundwater contamination can result. Most used oil in the U.S. is treated or re-refined, restoring the used oils to a usable state. But, meeting fuel or lubrication performance specifications entails a higher level of processing than decanting, settling, or filtering. The large number of contaminants potentially contained in used oil complicates the selection of appropriate treatment methods. A number of technologies of varying complexity have been proposed, or are currently in use, throughout the used oil industry. These technologies include variations of acid/clay or other chemical treatments, various distillation processes, cracking, hydrotreating, solvent treatment, and blending/compounding. Combinations of these treatment technologies with decanting, settling, and filtering are required to produce higher value oils. The degree and complexity of used oil treatment varies with the intended use of the end products. Producing a clear, light-colored lubrication stock that meets a variety of different machinery 2 manufacturer’s service requirements generally requires more complex treatment and blending than producing a used oil fuel. Capital costs usually increase the more sophisticated the treatment technology, but may be offset to some degree by higher-valued end products. As reported by the Clean Washington Center in its 1994 report “Used Oil to Diesel, An Alternative Technology”,1 an estimated 80% of used oil collected in Washington State is blended into heavy bunker fuels for use by ocean-going vessels; 14% is burned in land-based facilities. The remainder of the used oil collected is recycled into lubricants or finds other uses. The primary purchaser of used oil products in Washington state is Sound Refining Company, Inc. of Tacoma, a small refinery which produces asphalt and marine diesel products. Other significant purchasers include asphalt batch plants, sewage sludge dryers, and some industrial boilers. The current saturation of the Pacific Northwest heavy fuel oils market has resulted in depressed prices for used oil fuels.2 The lingering perception that used oil fuels are inferior products to fuels from virgin crude sources further complicates this segment of the petroleum market. With improved treatment, used oil could potentially be blended into higher-value, lighter fuel oils, perhaps resulting in an improved market price. The used oil treatment industry in the U.S. is characterized by numerous small operators struggling to survive and a small number of large re-refining facilities. Factors such as the wide dispersal of used oil sources, the aggressiveness of virgin oil marketers (major oil companies and their distribution channels), tax and environmental regulations, and technological changes in oil products have hindered the development of the used oil industry over the last twenty years. Small business lack the ability to respond to these unfavorable conditions because of their lack of resources. Most used oil companies in Washington State are small, poorly capitalized, marginally profitable, and staffed by personnel with relatively modest levels of technical education or expertise. Consequently, the challenges for Washington’s used oil industry are to find better treatment alternatives that are on a scale commensurate with the resources available to these businesses, 3 that produce affordable and safe, higher-value end products, and that are operable using available expertise. Technologies that allow used oil to be upgraded to lighter, higher value fuels rather than to lubricants may be the optimal alternative. 1.2 USED OIL TREATMENT ALTERNATIVES Historically, the most successful technology for treating used oils was the acid-clay process. This process is capable of producing good quality lubrication stocks, but also produces large volumes of petroleum-contaminated acid clay sludge. With the passage of the Resource Conservation and Recovery Act (RCRA) and later legislation, the sludge was classified as a hazardous waste requiring proper management and disposal. Consequently, the acid-clay process technology became uneconomic because of the high cost of managing the residues and is no longer used in Washington State. Used oil treatment using simple dehydration and volatiles removal through low temperature distillation (less than 300° Fahrenheit, 149° Celsius) is adequate to allow the sale of the treated oil as “cutter stock” for blending with heavy bunker oils. While this technology can significantly reduce water, antifreezes, and solvents in the used oil, it is limited in its ability to significantly reduce ash and other residues, seriously limiting product marketability. Along with settling, decanting, and filtering, low temperature distillation is used to treat used oils in most small-scale facilities. In “Used Oil to Diesel, An Alternative Technology”, the Clean Washington Center considered a high temperature (over 650°F, 343° C) cracking/distillation technology manufactured by Utopia Fabricating Ltd., Pennfield, New Brunswick, Canada (the Shurtleff Waste Oil Handling System). While achieving a degree of success in producing No. 2 and No. 3 diesel fuels, units produced by this firm are reported to have experienced severe operating problems. The company has reportedly gone into bankruptcy.3 Another company producing a unit utilizing similar high temperature cracking/distillation technologies, Green Oasis Environmental, Inc., Charleston, SC, manufactured and sold several production units but has also reportedly gone into bankruptcy.3 4 Other technologies such as hydrotreating, cracking, high temperature/pressure distillation, and blending/compounding are technically sophisticated and generally not economic, safe, or available at the small scale (relative to virgin oil refineries) at which Washington State’s used oil businesses operate. 1.3 THE SOLVENT EXTRACTION TECHNOLOGY The solvent extraction technology has the potential to produce oil products that are superior to those produced by the low-temperature distillation process currently in use. Figure 1 presents a simplified, conceptual process flow diagram for the solvent extraction technology. Used oil is mixed in the Reactor Column with an aliphatic solvent such as liquefied propane (butane, heptane or hexane may also be used). In this unit, the solvent acts selectively, dissolving the oil fraction and leaving the less soluble impurities. The oil-laden solvent is transported from the top of the Reactor Column to the Solvent Still (a distillation column) where the solvent fraction is separated from the oil for recycling within the process. The impurities (bottoms) slowly settle and coalesce in the bottom of the Reactor Column where they are pumped to the Bottoms Still (a second distillation column). Residual solvent is also separated in this unit. The recovered solvent is liquefied through a compressor and cooling system and reinjected into the Reactor Column through the Solvent Recycle Tank to repeat the cycle. While the solvent extraction process described here has been employed in some virgin crude oil refineries for refining of vacuum gas oils4,5, these units are not of a scale and simplicity of operation suitable for the used oil recycling industry. As part of complex lubrication stock rerefineries in Europe, solvent extraction has been successfully applied on a relatively large scale (30 million gallons, or 114 million Liters, per year).6,7 Several patents were issued on the technology as it was applied to asphaltic oils in refineries and to used oil recycling.8,9,10 These patents have now expired. Although more complex than the simple distillation technology discussed above, solvent extraction processes have the potential to be adapted for use at a scale and simplicity of operation consistent with the capabilities of Washington State’s used oil businesses. 5 Solvent Still Waste Oil Input Solvent Solvent Recycle Recycle Tank Cooling Oil Product Product Output Solvent Bottoms Still Asphalt Product The potentially improved oil products produced by the solvent extraction technology could be successfully blended into more valuable lighter diesel or heating fuel products, or into certain lubricating oil stocks. Because the solvent extraction technology separates a greater fraction of the impurities from the used oil than do existing low-temperature distillation technologies, fewer contaminants are burned when the products are used as fuel. The bottoms from the solvent technology, which resemble a light asphalt product, may also be a marketable product for such uses as the manufacture of asphalt shingles. 1.4 PROJECT OBJECTIVES This report presents the initial design and supporting documents for the construction of a pilot scale solvent treatment plant. The objectives for the project were as follows: • Determine key process parameters to guide the design of the pilot plant; • Design a pilot scale plant that produce sufficient quantities of used oil for product testing. 6 Subsequent phases of the project, subject to available funding and interested parties, will include the construction of a pilot unit. Upon construction, the project’s objectives should expand to focus on demonstrating the technology, including: • Testing of the pilot plant under varying operating parameters, such as different used oil sources, different solvents (propane and butane), different throughput rates, and varying quantities of water and ash. • Testing the physical and chemical characteristics of the oil product output. • Determination of market acceptance of the products by providing interested customers with test quantities. • Designing a full-scale facility. 7 2.0 LITERATURE SEARCH FINDINGS An initial review of the literature was made prior to conducting the design phase of the work. The findings are summarized here. • Much of the work on technologies for reprocessing of used oils was performed during the 1960s and 1970s. Many reprocessing plants were severely affected by hazardous waste regulations promulgated in the late 1970s and early 1980s, resulting in the permanent shutdown of large segments of the industry. Most of the used oil reprocessing that has survived appears to be based upon the low temperature (less than 300°F or 149°C) distillation technology.7 • At least two plants operating in Europe (Italy and the former Yugoslavia) in the 1970s used the solvent extraction process. No facility based on solvent extraction technology has apparently been constructed in the U.S. other than a pilot scale unit constructed by the Interline Corporation in Salt Lake City. 11 • The Institut Francais du Petrole (IFP) process, a solvent treatment technology developed in France, was reportedly successful in treating used oils to acceptable levels. Key operating parameters are reported in the literature.4 • Based on discussions with a retired Shell Oil chemical engineer with propane extraction plant experience, the solvent de-asphalting process used by the petroleum refining industry is very successful in removing heavy compounds from oil.12 However, the virgin oils treated by this process (vacuum gas oils) tend to be much heavier than used oils. The vacuum gas oils treatment plants operate at temperatures up to 400° F (204° C) and at much higher propane pressures than those that are suitable for small-scale facilities. Because of the difference in operating conditions and feedstocks for used oil, it did not seem appropriate to further research the de-asphalting process as used by the petroleum refining industry in the U.S. 8 • Solvent extraction is reported to be well suited for re-refining multigrade motor oils formulated with high concentrations of pour point improvers, viscosity index improvers, and other additives; and containing large amounts of varnish, gums, and other asphaltic compounds generated by heat and friction in their use. The solvent removes the mineral portion (phase) of the detergent present and precipitates water which is loosely bound chemically and contained in the detergent and the metalloorganic compounds. The solvent solubilization of the hydrocarbon phase also disassociates it from the deteriorated portion of the antioxidant compounds allowing the heavier antioxidant groups (also containing heavier metalloorganic compounds) to precipitate. Similarly, solubilization of the hydrocarbon phase of other additives such as the viscosity index improvers, the polar organic rust inhibitors, and the pour point depressants causes a similar disassociation of the deteriorated portion of these additives from the oils.7 3.0 3.1 PILOT PLANT DESIGN DESIGN ASSUMPTIONS This section of the report outlines the assumptions particular to the proposed host plant, Vintage Oil Inc., Anacortes, WA. The Vintage Oil facility treats approximately 3,000,000 gallons (11,350,000 Liters) per year of used oil by a process based on decanting, filtering, blending, and low-temperature distillation. Vintage Oil is therefore able to provide a feed oil to the pilot plant with no water, light ends (gasoline or light aliphatic solvents) or significant settleable solids. Vintage Oil will also provide in-kind project contributions specific to project requirements such as a secondary containment structure, electrical power, tankage, and other equipment. Because the Vintage Oil plant has the capability of providing a relatively consistent feed composition over a run period ranging from hours to days, a continuous process flow scheme was adopted for the pilot plant design rather than the batch process that was initially considered. A batch system would be advantageous for smaller or less complex systems, or where wide 9 variations in feedstocks could be expected. A continuous system allows for (optimally) adjusting the process variables to make small changes in product oil composition. Because of the pilot scale, the estimated nature of the input parameters, and the funding resources involved, rigorous calculations and computer modeling were not employed in the design. A target rate of 2,000 gallons (7,570 Liters) per day (approximately 730,000 gallons, or 2,760,000 Liters, per year) used oil feed was employed, with actual feed rate to be determined under live test conditions. The target rate is sufficient to produce the quantities of product needed for test marketing, but less than the economically efficient scale typical of a used oil recycling facility (typically over 2 million gallons, or 7,570,000 Liters, per year). The operating parameters for the primary Reactor Column were determined by the literature, primarily from the IFP process.6,9 An operating temperature of 120° F (49° C) and operating pressure of 230 pounds per square inch gauge (psig or 1586 kPa gauge) were selected as within the range quoted for the IFP process. Because of non-linear viscosity reducing effects, higher operating temperatures positively affect the ability of the Reactor Column to separate impurities from the oil (at the cost of higher resulting operating pressures and more complex process control). The lower end of the pressure and temperature operating regime was selected for the Reactor Column as a tradeoff between process efficiency and available vessel characteristics. Water in the used oil influent stream was assumed to be negligible (less than 2.0% by volume) as a design choice because of the pre-processing (dehydrating) capability of the proposed site. The literature indicates that solvent extraction technology should be capable of treating oils with significant water content (at least 10% by volume); however, higher oil treatment rates can be achieved by treating dried oil. In addition, the downstream separation of bottoms from water is simplified as well. A key parameter to be measured during pilot testing is the solvent-to-oil ratio. The literature indicates that a ratio of 1:1 is too low to be efficient in achieving good separation of bottoms. A ratio of 20:1 was reported as yielding good lubrication base stock.7 Since the pilot plant was 10 being designed for fuel oil production, a lower ratio seemed appropriate. A nominal selection of ratios in the range of 3:1 to 5:1 was targeted. Higher solvent to oil ratios reduce the oil throughput and increase the solvent recovery requirements. 3.2 DESIGN DOCUMENTS Design documents prepared for the pilot scale unit are presented in Figure 2, Process Flow Diagram; Figure 3,Piping and Instrumentation Diagram; and Figure 4, Vintage Oil Solvent Treatment Pilot Plant Equipment List. Used oil feedstock enters Tank T-301 from the host facility at a rate of 2 gpm (7.57 Lpm). Within tank T-301, the used oil feed is heated to approximately 173°F (78° C) by a steam-heated coil within the tank. The feed oil is pumped through pump P-101 into the in-line mixer M-101, where it is mixed with 3 gpm (11.4 Lpm) of solvent. This solvent is added from working storage tank T-201 via pump P-201. The proper ratio of 5:1, solvent to oil, is maintained by monitoring flow meters on both oil and solvent lines. The oil/solvent mixture is input to the Reactor Column D-101 through a distribution header at a point near the midpoint on the column. Solvent at a rate of 7 gpm (26.5 Lpm) is added at a lower point to Reactor Column D-101. Within Column D-101, the solvent acts on the used oil to solubilize the oil fraction and allow the less soluble contaminants (with higher densities) to settle. The propane also reduces viscosity allowing the settling to proceed more quickly, although the degree of separation is a function of residence time within Column D-101. Although some solvent and oil is carried with the asphalt bottoms, there is a net upward flow of solvent/oil mixture to the top of tank D-101. Liquid solvent and oil leaves Column D-101 and is allowed to expand through valve V-110 as it enters the Solvent Still, Column D-102. Within Column D-102, the pressure is maintained near atmospheric and the temperature is elevated. Pressure within the column is maintained by evacuation of solvent vapors by compressors C-201 and C-202 and by addition of heat through the reflux oil system. Solvent vapors removed by the compressors are first routed through an oil overflow collection trap, S-201, to prevent liquid oil from accidentally entering the compressors. After compression, the vapors are then routed through the solvent vapor condenser H-201 before 11 collection in solvent storage tank T-201 for re-use. The reflux oil system uses pump P-102 to withdraw oil from near the bottom of Column D-102 and pump it through reflux heat exchanger H-101 where the temperature of the oil is increased by heating with steam. The hot oil is then sprayed over the column packing to increase surface area and promote offgassing by the oil. Oil mist is trapped within the column by mist eliminator E-101. A sidestream of product oil, the clean fuel oil, is removed from the bottom of column D-102 which has had the substantial portion of solvent stripped from it. Within column D-103, the bottoms from column D-101 are maintained at an elevated temperature of 150°F (66° C) for a prolonged period (several hours or longer) to allow efficient recovery of solvent through valve V-117 and into the solvent recovery system. As needed, the bottoms are removed from column D-103 through pump P-103. As designed, the process is monitored by use of flowmeters in the input oil and input solvent lines, the solvent/oil transfer line to column D-102, the reflux oil line, the steam flow line to reflux heat exchanger H-101, and in the clean fuel oil product line (refer to the drawing in Figure 3, the P&ID). Flow rate from column D-101 to D-102 is used as a control parameter for valve V-110. Temperature is monitored at one point in the reactor column D-101 and bottoms distillation tank D-103, but at five points vertically along flash distillation column D-102. Column D-102 temperature is used to control steam flow to the reflux heat exchanger H-101. Pressure is monitored at one point in the reactor column D-101, bottoms distillation tank D-103, and within the solvent storage tank T-201, and at two points vertically along flash distillation column D-102. Emergency pressure release valves were provided on each of the main columns D-101, D-102, and D-103. Valves for isolation and maintenance of the major components have been provided as well as for emptying solvent from the major vessels. ASME specifications for pressure vessels must be followed along with good engineering practice for LPG systems. Because of the small volumes of material transferred among the vessels and 12 tanks of the pilot plant, the piping was sized to be consistent with low pressure drop and to match valves, flanges, and other provided equipment provided by Vintage Oil. Figure 4,included as Appendix A, provides the equipment list for the pilot scale treatment plant. Where the term “project specific” has been applied, the host site is to supply with existing equipment on hand. 13 14 INSERT FIGURE 3 15 4.0 4.1 FURTHER DEVELOPMENT OF TECHNOLOGY PILOT-SCALE Once a pilot plant has been constructed, testing should be directed toward evaluating the effectiveness of the solvent technology in cleaning used oils. Specifically, the improvement of physical and chemical characteristics of the oil product as compared to the used oil feedstocks should be evaluated for different feedstocks. Parameters to be considered during testing include: reduction in ash content, heavy metals content, and viscosity, and increasing flashpoint temperatures. These parameters directly affect the potential acceptance of the product oil by the market. Sufficient quantities of product oil should also be produced to provide potential customers for testing in their facilities. Future system design should investigate in greater detail the potential for product oil foaming. It is anticipated that the solvent treatment process would remove anti-foaming agents which would ordinarily serve to limit product oil foaming. With elevated operating temperatures, this issue may not be problematic, but should nevertheless be considered. Evaluation of this potential pipe fouling mechanism should be evaluated during pilot plant operation. Stripping the clean oil from the solvent following the solvent extraction step is key to process efficiency. Under actual conditions, separation will never be perfect. There will be some solvent that is lost in the oil. Determining acceptable solvent losses at the pilot scale is an important design consideration for the full-scale implementation. Effective recovery of the solvent must also be achieved to ensure that product oil will meet flash point specifications. The effectiveness of the solvent technology in cleaning oils containing certain soaps used in cleaning petroleum-coated parts and equipment must be evaluated at the pilot scale since there is a significant quantity of used oil containing these materials. Some of these soaps are ether-based and are soluble both in oil and in water. Soap materials are very effective emulsifiers and pose challenges to the current used oil recycling methods and potentially to the solvent technology as well. 16 The question of whether raw (wet) used oil can be treated directly or whether dehydrated used oil must be used should also be addressed in the pilot scale testing. Additionally, the effectiveness of the solvent technology for treating synthetic oils must be evaluated at the pilot scale since these oils appear to be a growing fraction of the used oil stream being recycled. 4.2 FULL-SCALE In the pilot plant, a single solvent still was specified. In larger implementations, multi-stage distillation flow sheets will probably be required for improved process efficiency. With optimal operating point selection, recovery and liquefaction of a significant fraction of the solvent may be accomplished using cooling towers rather than compressor capacity. This can reduce energy requirements and operating costs. A full-scale implementation should also take into consideration asphaltic tar handling requirements and solvent losses in the tar. Rapid depressurization of the bottoms during transfer from the reactor column to the bottoms distillation vessel may result in frozen solids formation or freezing of any water present. Significant quantities of pressurized solvent will be present in the bottoms. 4.3 SUMMARY The used oil industry in Washington State, as well as in other parts of the U.S., is in need of a cost-effective alternative treatment technology for upgrading used oil into more refined products, either fuel or lubrication stocks. The solvent treatment technology presented in this report, alone or in combination with existing used oil dehydration facilities, has the potential to significantly reduce impurities in the product oil currently produced by used oil treatment companies. A pilot scale solvent extraction plant is needed to refine the design, test with a wide variety of used oil streams, evaluate treatment costs, and produce sufficient quantities of product oils and asphalt bottoms to promote acceptance testing with customers for these products. 17 When a pilot unit is constructed, the remaining objectives identified in Section 1.3 above can be accomplished: testing under varying operating parameters and different sources of oil; characterizing the physical and chemical parameters of the product oil; determining market acceptance of the product oils; and determining the requirements for a full-scale plant. 18 5.0 ACKNOWLEDGMENTS The following organizations contributed their time, effort, support and understanding during the conduct of this project: 1. Vintage Oil Inc., Anacortes, Washington. 2. AERCO, Inc., P.S., Lynnwood, Washington. ReTAP is a joint venture of the Clean Washington Center, Washington State’s lead agency for the market development of recycled materials, and the National Recycling Coalition, a 3,500 member nonprofit organization committed to maximizing the benefits of recycling. ReTAP is an affiliate of the national Manufacturing Extension Partnership (MEP), a program of the U.S. Commerce Department’s National Institute of Standards and Technology. The MEP is a growing nationwide network of extension services to help smaller U.S. Manufacturers improve their performance and become more competitive. ReTAP is also sponsored by the U.S. Environmental Protection Agency and the American Plastics Council. 19 6.0 1. REFERENCES Used Oil to Diesel, An Alternative Technology, The Clean Washington Center, A Division of the Department of Trade & Economic Development, June 1993, Seattle, WA. Report Number B21. 2. Time to End the Alaskan Oil Export Ban, S.A. Van Vactor, Economic Insight Inc., Policy Analysis No. 227, Cato Institute, May 18, 1995. 3. Telephone Conversation with Frank Pustka, President, P&S Pacific, Inc. and Oil ReRefining Company of Hawaii, Inc., June 29, 1995. 4. Proceedings of the International Conference on Waste Oil Recovery and Reuse, Sponsored by the Association of Petroleum Re-Refiners and Information Transfer, Inc., February 1214, 1974, Washington D.C. 5. Waste Oil: Reclaiming Technology, Utilization & Disposal, Mueller Associates, Inc. (compiled by staff), Noyes Data Corporation, Park Ridge, N.J., 1989. Pollution Technology Review No. 166. 6. Waste Oil Recovery and Disposal, Vaughn S. Kimball, Noyes Data Corporation, Park Ridge, N.J., 1975. Pollution Technology Review No. 20. 7. Reprocessing and Disposal of Waste Petroleum Oils, L.Y. Hess, Chemical Technology Review No. 140, Noyes Data Corporation, Park Ridge, N.J., 1979. Pollution Technology Review No. 64. 8. U.S. Patent 2,196,989, Process for Treating Hydrocarbons, Robert W. Henry and James V. Montgomery, Okmulgee, OK, assignors to Phillips Petroleum Company, a corporation of Delaware, April 16, 1940. 9. U.S. Patent 3,773,658, Process for Regenerating Used Lubricating Oils, Quang Dang Vu, Paris; Francois Audibert, Lyon; Jean Francois Boucher, Saint Germain en Laye; Henri DeVille, La Celle Saint Cloud, all of France, assignors to Institut Français du Pétrole, November 20, 1973. 20 10. U.S. Patent 3,870,625, Process and Equipment for the De-Asphalting of Residues from Vacuum Distillation of Petroleum, and Application to the Remaining of Lubricant Oil, Leck Godfryd Wielezynski, Paris, France, March 11, 1975. 11. Interline Process Improves Re-refining Affordability, H. Hydrick, Lubricants World, November 1994, p. 26. 12. Conversation with Ernest D. Morris, retired Shell Oil Company chemical engineer, Meeting at Vintage Oil Inc. plant, September 21, 1994. 13. Conversion of Crankcase Waste Oil Into Useful Products, Solfred Maizu and Kenneth Urquhar, National Oil Recovery Corporation for the Water Quality Office of EPA, March 1971. EPA Report No. EPA-WQO-15080-DBO. 14. Large Grassroots Lube Rerefinery in Operation, D.W. Brinkman, Oil and Gas Journal, August 19, 1991, p. 60-63. 15. Studies in Chemical Process Design and Synthesis; An Expert System for Solvent-based Separation Process Synthesis, Industrial & Engineering Chemistry Research, February 2, 1993, p. 315-334. 16. Round Table Discussion on Used Oil Recycling and Re-refined Base Oils, J.A. Patel, Symposium on Processing, Characterization and Application of Lubricant Base Oils, August 23-28, 1992, Preprints - Division of Petroleum Chemistry, American Chemical Society. 17. Solvent Demetalization of Heavy Oil Residue, A.S. Farag, et.al., Hungarian Journal of Industrial Chemistry, Vol. 17, 1989, p. 289-294. 18. Evaluation of the B.E.S.T. (Trade Name) Solvent Extraction Sludge Treatment Technology Twenty-Four Hour Test, G.W. Sudell, Enviroresponse, Inc., EPA-68-03-3255, 1988. 19. Waste Oil Recycling & Resource Recovery, Survey on Technology & Markets Ser., R. K. Miller and M.E. Rupnow, Future Tech Surveys 1991, No. 176, 1991. 20. Used Oil Disposal and Recycling in the United States, Argonne National Lab., IL., Sponsored by U.S. Department of Energy, July 1993. 22p. 21 APPENDIX A EQUIPMENT LIST 22 23 24 25 26 27