Oil shale conversion

This work was supported by NSF Grant AER75-17453 A Study of the Use of Microwave Heating for the Release of Oil from Oil Shale. Portions of this paper were presented at the Annual Oil Shale Conversion Symposium, September 1977, University of Wyoming, Laramie, Wyoming and at the Symposium on Thermal Hydrocarbon Chemistry presented before the Division of Petroleum Chemistry, American Chemical Society. 

Touring 1970 and 1971, the energy industries addressed themselves to the feasibility of rapidly approaching synthetic fuels industry. Decisions were made to expend a considerable monetary and manpower eflFort to keep the petroleum industry abreast and informed of this new developing technology. These initial efforts resulted in decisions by Ashland Oil and a number of other corporations to participate in coal-and oil shale-conversion process development. 

Anticipating a future shortage of petroleum and acknowledging the uncertainty of continuing to obtain this vital resource from some of the major petroleum producing countries have caused an increased world interest in the extraction of liquid fuels from oil shale. This interest is evidenced by the exploration for new deposits, reevaluation of known deposits, new research studies of oil shale conversion, and the development of new retorts and retorting technology. However, there has been little, if any,... 

By combining solid- and liquid-state NMR with elemental analyses and mass balance data, insight into some of the chemistry that occurs during oil shale conversion can be gained, which has practical applications in fossil fuel conversion processes. For example, during pyrolysis there is an increase in the amount of aromatic carbon in the products (oil plus residue) over that in the original shale.This increase is produced at the expense of aliphatic carbon... 

Thiophene [110-02-17, C H S, and dibenzothiophene [132-65-OJ C22HgS, are models for the organic sulfur compounds found in coal, as well as in petroleum and oil shale. Cobalt—molybdenum and nickel—molybdenum catalysts ate used to promote the removal of organic sulfur (see Coal CONVERSION... 

Petroleum refining, also called petroleum processing, is the recovery and/or generation of usable or salable fractions and products from cmde oil, either by distillation or by chemical reaction of the cmde oil constituents under the effects of heat and pressure. Synthetic cmde oil, produced from tar sand (oil sand) bitumen, and heavier oils are also used as feedstocks in some refineries. Heavy oil conversion (1), as practiced in many refineries, does not fall into the category of synthetic fuels (syncmde) production. In terms of Hquid fuels from coal and other carbonaceous feedstocks, such as oil shale (qv), the concept of a synthetic fuels industry has diminished over the past several years as being uneconomical in light of current petroleum prices. 

Supercritical fluid solvents have been tested for reactive extractions of liquid and gaseous fuels from heavy oils, coal, oil shale, and biomass. In some cases the solvent participates in the reactions, as in the hydrolysis of coal and heavy oils with water. Related applications include conversion of cellulose to glucose in water, dehgnincation of wood with ammonia, and liquefaction of lignin in water. 

Hutton, A. C. 1995. Organic petrography of oil shale. In Snape, C. (ed) Composition, Geochemistry and Conversions of Oil Shales. Kluwer Academic Publishers, Doordrecht, Boston, London, 17-33. 

The primary purpose of the energy conversion facility is the production of liquid or gaseous fuels most of the sulfur will be removed from these products. Liquid fuel streams will be hydro-desulfurized to meet combusion standards, with the sulfur transferred to the gas phase. In the case of oil shale, extensive hydrotreatment will be required to remove the refractory nitrogen compounds from the oil. With this degree of treatment, the sulfur will also be removed. 

One of the primary problems to be encountered in energy conversion facilities will be the variability of the feedstock. A coal or oil shale facility will probably see greater variability, day-by-day, than experienced in planned changes in oil refinery crude runs. Even with extensive blending in the feed stockpile, the variation in feed characteristics will be significant. 

Plants to process alternate sources of energy will make low-sulfur fuels from high-sulfur feeds such as coal, oil shale, tar sands, or heavy oil. Elemental sulfur will be a normal byproduct. Nearly all processing schemes first produce H2S from the sulfur compounds in the raw material, and then convert H2S to elemental sulfur. Usually this conversion step is labelled "Claus Process". 

The importance of sulfur as an industrial chemical is discussed and forecasts of projected sulfur demand in the U.S. are given. Three processes for conversion of coal and oil shale to synthetic fuels are examined in some detail to show how the sulfur in the original feedstock material is recovered as elemental by-product sulfur. Three synthetic fuel scenarios are examined and their potential impact on sulfur availability with current and projected markets to the year 2000 are examined. 

This consideration as well as those concerning cost, convenience of use, and availability leads to the conclusion that petroleum fuels will be used for transportation purposes in preference to other fuels as long as crude petroleum is available. Although liquid fuels can be produced from gas, coal, or shale oil, the high energy losses involved in the conversion make such operations unattractive from an energy conservation point of view. Obviously, the direct utilization of gas and coal as produced and of the type of crude oil which can be produced from oil shale by simple retorting is the most desirable procedure and should be followed until petroleum is so scarce or expensive to find that the free play of economic forces dictates the synthesis of liquid fuels. 

Energy sources and conversion— biomass, batteries, fuel celts and fuel cell technology, hydrogen as a fuel, liquid and gaseous fuels from coal, oil shale, tar sands, nuclear fission and fusion, lithium lor thermonuclear reactors, insulating materials, and solar energy. 

Hydrocarbon-producing resource a resource such as coal and oil shale (kero-gen) which produce derived hydrocarbons by the application of conversion processes the hydrocarbons so-produced are not naturally-occurring materials. 

Synthetic crude oil (syncrude) a hydrocarbon product produced by the conversion of coal, oil shale, or tar sand bitumen that resembles conventional crude oil can be refined in a petroleum refinery (q.v.). 

When coal, oil shale, or tar sands are pyrolyzed, hydrogen-rich volatile matter is distilled and a carbon-rich solid residue is left behind. The carbon and mineral matter remaining behind is the residual char. Pyrolysis is one method to produce liquid fuels from coal, and it is the principal method used to convert oil shale and tar sands to liquid fuels. Moreover, as gasification and liquefaction are carried out at elevated temperatures, pyrolysis may be considered the first stage in any conversion process. 

Progress has been slowed by some governments refusal to provide leadership. It is unfortunate that conversion to renewable energy became a right-left issue, as if only the left of the planet is warming. On the issues of tax breaks for the oil industry, coal-to-liquid subsidies, oil shale exploration or... 

JACK ARORA is Supervisor of Process Economics at the Institute of Gas Technology. He contributes to process economics studies in the evaluation of new technologies for conversion of coal, oil, shale, and biomass to clean and useful fuels. 

Shale oil is of special interest here because of its comparatively high hydrogen content, similar to that for petroleum and about twice that in coal. This feature is especially attractive for conversion to fuels and feedstocks. A short but comprehensive review of the huge oil shale potential in the United States is given in Ref. 1 it notes some of the... 

Oil shale represents an enormous reserve of fossil fuel for domestic and foreign needs (1,2). Shale oil production can be divided into direct and indirect heating processes (2). In direct heating, some of the products or some other fuel is combusted to raise the oil shale to the necessary temperature for conversion to gas and oil while an indirect process transfers heat from an outside source. Although high yields have been demonstrated in some indirect procedures (3), the application to in situ retorting has been limited. Direct processes developed for in situ recovery of shale oil have not demonstrated sufficient control of the underground combustion for reliable operation. 

A Fischer assay simulates the conversion of oil shale to usable fuels in an above-ground retort. The results of an extensive program of chemical analysis of major and trace elements in spent shale, oil, and water collected from the Fischer assay of a standard oil shale are presented. The concentration of major elements in raw and spent shale can be determined only to 10% in this study. Two criteria show that fluorine and zinc may have been mobilized during the assays. The concentrations of arsenic and selenium in the Fischer assay retort water exceed the maximum permissible concentrations for drinking water. 

Oil shale and coal conversion technologies are presently in a stage of rapid development. Analysis of materials involved in these processes is an important part of the investigation of possible environmental and health impacts of the processes. High precision analyses are desirable even in those cases where sampling uncertainties are relatively large, so that the analytical procedures will not add appreciably to the overall error. 

Activated carbon fibers made from various precursors have been investigated (i.e., polyacrylonitrile or PAN, coal tar pitch, petroleum pitch, and oil shale tars) and have all exhibited high activity for SO2 conversion [47]. It has also been shown that heat treatment of the fibers can increase the catalytic activity, the extent of change being dependent upon the type of fiber, and the heat treatment temperature and atmosphere [48]. 

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