Recovery and hydropyrolysis of oil from Utah's tar sands

reportDuring the past five years, new technology has been developed for fast flotation of Tar Sand with an air-sparged hydrocyclone. Conventional flotation in a stirred, aerated tank requires retention times on the order of minutes, whereas intrinsic bubble attachment times are on the order of milliseconds. This rate limitation for conventional flotation is due to the low probability of collison events, insufficient particle inertia to penetrate the bubble film and instability of bubble/particle aggregates. The design of the air-sparged hydrocyclone was envisioned to establish a controlled, high force field by swirl flow of the slurry to increase the inertia of fine particles and to produce, by introducing air through a porous cyclindrical wall, a high density of fine bubbles with directed motion orthogonal to the particles to improve collision efficiency. The net result is a flotation rate with retention time approaching intrinsic bubble attachment times. This corresponds to a capacity on the order of 1-2 tpd/ft of cyclone volume, at least 50 times the capacity of conventional flotation cell of comparable volume. In this regard, research was initiated to test the effectiveness of air-sparged hydrocyclone in the flotation of bitumen from digested tar sand slurry prepared according to the conditions and procedures that had been established from previous DOE sponsored research on the hot water processing of the Utah tar sands

Recovery and upgrading of oil from Utah tar sands

reportResearch has progressed in four principal areas: A) Bitumen Upgrading; B) Thermal Recovery by Fluidized Bed Pyroiysis; C) Water Assisted Recovery; and D) Two-Stage Thermal Recovery using Heat Pipes. Hydropyrolysis continues to show promise for upgrading of bitumen with high liquid yields. Valuable experience has been gained in the operation of the 2 £/hr PDU. The semiquantitive effects of the important process variables have been ascertained. High conversions to liquids and low coke production can be achieved with good atomization quality in the PDU. The product distribution obtained when processing the TS-IIC liquid product at 505°C, 1800 psig H2, and 2.8 sec. residence time was 4.7% gas, 84.5% liquid (24.9° API), 10.6% residual liquid and 0.2% coke. The investigation of the fluidized bed pyroiysis of the bitumenimpregnated sandstone from the PR Spring Tar Sand deposit has been completed, and the results have been incorporated into the correlation used to predict pyroiysis product distributions and yields. The differences in the nature of the three native PR Spring bitumens, Rainbow I, Rainbow II, and South, were reflected in the product distributions and yields as a function of reactor temperature and sand retention time and in the product qualities. The Conradson Carbon Residue, the atomic hydrogen-to-carbon ratio, and the asphaltene content of the native bitumens were excellent correlating parameters for the product distributions and yields. The kinetics of the pyrolysis reactions are currently being studied in an attempt to refine the pyrolysis model for the fluidized bed process. In water-assisted recovery, shear forces are known to be important to bitumen disengagement. Both cohesive and adhesive forces must be overcome in order to attain high recovery of the bitumen. This phenomena has been studied using a high speed video system to elucidate the separation of the bitumen from the sand substrate. Results indicate that cohesive forces which can be controlled through viscosity-reducing diluents contribute significantly to the stability of the bitumen-sand interface. A residual amount of bitumen remains in contact with the sand grains, depending upon the level of shear achieved due to adhesive forces between the bitumen and the sand surface. Results are to be used in improving the design of water-assisted recovery processes. Preliminary design and economic evaluation for a two-stage thermal recovery process was conducted. The process design study, using heat pipes to transfer heat from the exothermic combustion zone to the endothermic pyrolysis zone, included two cases: 15,000 and 50,000 bbl/day. Projected capital investments were $137M and$468M, and operating costs were $13.30 and$14.48/bbl, respectively. The design basis assumed a purchase cost of $5/ton of raw ore. Product oil was a raw pyrolysis oil. The design is accompanied by a second-law thermodynamic analysis. Results show that the process is stable and easily controlled, and represents an economically attractive method for hydrocarbon recovery from tar sands

The extraction of bitumen from western oil sands

reportThe information required for compliance with the National Environmental Protection Act (NEPA) has been documented in this section. This final report has been prepared to reflect the research and development activities performed under the cooperative agreement 89MC26268 between the University of Utah, Department of Chemical and Fuels Engineering and the U.S. Department of Energy. Detailed descriptions of the individual projects, process flow diagrams for the various oil sand recovery technologies, laboratory locations, environmental impacts, health and safety procedures, etc. have been documented in detail in the 1991-92 final report for the cooperative agreement 89MC26268. . All liquid and solid waste materials produced during the course of the experimental program will be processed through the EPA approved University of Utah Safety Services disposal system. This section includes an NEPA checklist and a brief description of the program and its overall environmental impact. The information provided essentially qualifies the program for CX-B exclusion determination

High Conversion of Coal to Transportation Fuels for the Future With Low HC Gas Production

An announced objective of the Department of Energy in funding this work, and other current research in coal liquefaction, is to produce a synthetic crude from coal at a cost lower than $30.00 per barrel (Task A). A second objective, reflecting a recent change in direction in the synthetic fuels effort of DOE, is to produce a fuel which is low in aromatics, yet of sufficiently high octane number for use in the gasoline- burning transportation vehicles of today. To meet this second objective, research was proposed, and funding awarded, for conversion of the highly-aromatic liquid product from coal conversion to a product high in isoparaffins, which compounds in the gasoline range exhibit a high octane number (Task B)

Recovery and upgrading of oil from Utah tar sands

reportThe University of Utah tar sands research and development program has progressed well in its second year of the current three-year contract. The program has advanced significantly toward its long-term objectives. The long-term objectives of this program remain the development of scientific and engineering data required for the commercialization of domestic tar sands. Areas that have been given research attention are bitumen upgrading, thermal recovery by fluidized bed retort, thermal recovery by an energy efficient heat pipe process, and water-assisted separation of bitumen from ore. In the area of bitumen upgrading, substantial progress was made in understanding the chemistry of upgrading bitumen to distillate products. A reaction network for hydropyrolysis was proposed and verified using model compounds and petroleum distillates. The model is based on the carbon-type description of the bitumen. The principal reactions in hydropyrolysis are cracking of paraffins and naphthenes, dealkylation of aromatics, cracking of naphthenoaromatics, hydrogenation of aromatics, and dehydrogenation of naphthenes to form aromatics. Reaction kinetics of each of these reactions were studied. A very important finding was that the dealkylation reactions are fast reactions and are directly related to the hydrogen-atom concentration in the reaction system. The hydrogen-atom concentration can be estimated through an index developed based on propane and propyleneconcentrations. Hydrogen consumption was determined as a function of the various reactions taking place that require hydrogen. In this analysis, it was found that most of the hydrogen is required for the non-condensible gas production. Thus, it has been reaffirmed that optimum conditions for hydropyrolysis will constitute those conditions which produce the maximum amount of liquid with the greatest liquid quality. The results of this work will greatly assist the engineering design phase for the third year of the project. 3 Studies of thermal recovery of bitumen using fluidized-bed technology have also progressed well. A four-inch reactor has been designed and partially fabricated under the second year of this funding. This reactor design is based in part on a kinetic model which was produced from the small scale reactor. This model contains the reaction rate constants for the reactions of bitumen, heavy oil, and light oil to the various gaseous, liquid and coke products. Both a numerical and an analytical solution were obtained for the reaction network. Fluidized-bed retorting of tar sands continues to show promise as an operable and viable method for recovering values from tar sands. Process design, economic evaluation, and thermodynamic analysis were completed for the University of Utah two-stage thermal recovery process. In this process, thermal energy for heating the feedstock is obtained from the energy released by combustion in the lower bed. Economic analysis were conducted for a 50,000 and a 15,000 bbl/day plant for feedstocks containing 8, 10, and 12% bitumen. Costs for the 50,000 bbl/day plant case were $16.32/bbl for the 8$9.44/bbl for the 12% bitumen case. Capital costs were $418,000,000 and$343,000,000 for the two cases, respectively. Capital investment per unit capacity is relatively insensitive to plant size between 50,000 and 15,000 bbl/day because multiple units of maximum size equipment are necessary in most sections of the plant. Details of the economic evaluation are contained in the body of the report. In the modified hot water separation technology research, a better understanding was obtained in the area of the mechanism of displacement of bitumen from the surface of the sand. A fundamental study of the adhesion energy associated with the bitumen solid interface was initiated to further understand this mechanism. This analysis involved the measurement of the surface tension of bitumen solutions at various temperatures, and the measurement of the contact and angle between the sand surface and the bitumen. The hot water process was also studied in a low-shear force field. The results from the development of this low-shear digestion procedure are expected to be of significance in 4 the commercialization of the hot-water process. Under the low-shear conditions, ultimate recovery was found to be in excess of 90%. Percent of bitumen in the concentrate remains at an acceptable level except for certain cases at lower temperatures. Low shear conditions are expected to result in reduced energy requirements at the commercial level. Progress in our second year has been sufficient that renewed attention is now being paid to the ultimate tasks of comparative analysis of various technologies and technology selection. In the third phase of our current contract period, efforts will be made to establish a basis whereby such a study can commence. Process selection and final engineering design data will be the subject of work during the next contract period

Production of bitumen-derived hydrocarbon liquids from Utah's tar sands

reportIn previous work done on Utah's tar sands, it had been shown that the fluidized-bed pyrolysis of the sands to produce a bitumen-derived hydrocarbon liquid was feasible. The research and development work conducted in the small-scale equipment utilized as feed a number of samples from the various tar sand deposits of Utah and elsewhere. The results obtained from these studies in yields and quality of products and the operating experience gained strongly suggested that larger scale operation was in order to advance this technology. Accordingly, funding was obtained from the State of Utah through Mineral Leasing Funds administered by the College of Mines and Earth Sciences of the University of Utah to design and build a 4-1/2 inch diameter fluidized-bed pilot plant reactor with the necessary feeding and recovery equipment. The current United States Department of Energy contract supplied the funds to test and operate the unit. This report covers the calibration and testing studies carried out on this equipment. The tests conducted with the Circle Cliffs tar sand ore gave good results. The equipment was found to operate as expected with this lean tar sand (less than 5% bitumen saturation). The hydrocarbon liquid yield with the Circle Cliffs tar sand was found to be greater in the pilot plant than it was in the small unit at comparable conditions. Following this work, the program called for an extensive run to be carried out on tar sands obtained from a large representative tar sand deposit to produce barrel quantities of liquid product. For the extended run, a moderately high grade ore from Whiterocks was obtained. Operation with this grade of tar sand (8-11%) bitumen presented many difficulties, including significant problems with ore preparation, ore feeding, and product recovery. The problems encountered and solutions devised are described in the report in detail. The unit w as made operable and many days of operation were accomplished. Approximately one barrel of product was made and extensively evaluated. The overall material balance from the operation was excellent, and yields of liquid product in excess of 55 wt % of the bitumen fed to the unit were obtained. The API gravity was increased and weight percent of the product boiling below residuum temperatures was 87.5%, as compared with only 25.4% for the native bitumen. The experience obtained with these studies has provided sufficient data to justify further development of the fluidized-bed concept for tar sand processing. We feel very confident that with further upgrading of the unit, it will be ready for around-the-clock operation with Utah's tar sands with excellent results

Recovery of oil from Utah's tar sands

reportThis project is designed to develop necessary engineering data and technology for recovery of oil from Utah's tar sands. Progress reports for four major aspects of this project, namely Hot Water Recovery, Energy Recovery in Thermal Processing, Effect of Variables in Thermal Processing and Bitumen Processing and Utilization are covered. Efforts have progressed to the point where collaboration with engineering companies for pilot plant development in preparation for commercialization has commenced. Hot water recovery technology has been shown to be technically feasible for application to high and medium grade Utah tar sands. Utah tar sands are generally believed to be oil-wet and the conditions for efficient separation differ appreciably from those practiced in commercial operation with Athabasca, Canada tar sands. The occurrence of high silica, low clay content tar sands in Utah may dramatically reduce water requirements and may eliminate the need for tailings ponds as required for Athabasca tar sands. Further work is required to prove this point. In recent work, a factorial design study of the major operating variables in the flotation step of the two step hot water process using Asphalt Ridge material has been carried out. Preliminary results are presented in this report. Considerations of energy balance and recovery in thermal processing show that there is sufficient energy available from combustion of coked sand above about 8 weight percent bitumen grade. Below 8 weight percent external energy must be input, preferably through the introduction of coal in the combustion zone. An energy efficient process concept, using heat pipes for energy transfer has been tested and shown to be attractive from a conservation standpoint. Further efforts must be made to prove out economic viability ii and operability relative to other thermal process configurations. A fluidized bed recovery process employing an arrangement of steps similar to that used widely in catalytic cracking has been studied in this laboratory. The principal variables effecting recovery and product quality are temperature, solids retention time, particle size, and particle size distribution. For a specified solids retention time, an optimum temperature for production of liquid products exists, below which insufficient production occurs, and above which raw crude oil is cracked to form more gases. Yields of greater than 80% raw crude oil are anticipated at residence times of less than 20 minutes. Detailed studies of energy recovery methods in thermal processing have been initiated for a two stage fluidized bed system just described. Characterization studies on extracted bitumen and the synthetic crude liquids obtained during pyrolysis were initiated to determine molecular composition of these tar sand oils and to develop concepts of reactions occurring during the pyrolysis. Some results of this work are presented. Virgin bitumen can be converted to raw crude oil by a variety of primary upgrading processes including visbreaking, coking, catalytic cracking and hydropyrolysis. Compared to coking, direct catalytic cracking provides higher quality products in greater yields; however, optimum conditions for catalytic cracking have not been identified and comparative economic analyses have not been made. Bitumen can be converted in virtually 100% yields to hydrocarbon gases and liquids by hydropyrolysis with the addition of 1 to 3 wt. percent hydrogen. Hydropyrolysis products show good promise as a catalytic cracking or a steam pyrolysis feedstock. Steam pyrolysis of bitumen to produce chemical intermediates is now underway

Recovery of oil from Utah's tar sands

reportThis report covers the work accomplished at the University of Utah on Utah's tar sands during the period: October 1, 1979 to March 31, 1983. The work reported is a continuation of the program carried out over a period of years at the University. The primary effort of the work covered in this report has involved expanding the four major areas of the previous work (see Final Report for Contract #ET77-S-03-1762): Section A: Hot Water Recovery of Bitumens. Section B: Thermal Recovery of Bitumens in a Fluidized Bed. Section C: Upgrading and Utilization of Bitumens. Section D: Energy Recovery in a Thermal System Utilizing Heat Pipes. In the previous report it was reported that work has progressed to an extent that prospects looked good for the design, construction and operation of a pilot plant to prove out the University of Utah water extraction technology. A pilot plant, funded by the State of Utah and Enercor, a private company was designed, built and operated on Utah's tar sands. After some difficulties arising largely from feed stock selection, the plant ran well on Asphalt Ridge and White Rocks tar sands. Operation was discontinued when funding became difficult as a result of world oil easement and interest in synthetic fuels waned. However, research was continued during this time and substantial advances have been made in each of the major areas and these are described in the following pages of the report

The extraction of bitumen from western oil sands: Volume 2

reportIn these days of plentiful fuel supplies, synthetic fuels are not in demand; but with the current rate of consumption of oil the importance of synthetic fuels will only increase. The United States currently imports 50% of its transportation fuel and such a dependence could be potentially dangerous, as was evidenced by the 1973 Arab oil embargo. Hence it is important to develop technologies that will make it economically feasible to utilize reserves to produce synthetic fuels. Natural bitumen, which includes materials commonly termed as tar sands, oil sands, or natural asphalt, is a significant potential source of synthetic fuel and this work deals with optimizing the operation of a thermally-coupled fluidized-bed tar sands extraction process