Showing papers on "Carbochemistry published in 1979"

Some proved and unproved effects of coal geochemistry on liquefaction behavior with emphasis on U. S. coals

Abstract: The paleobotany of coal origins is examined along with studies of the dependence of liquefaction behavior of U.S. coals on coal characteristics; influence of rank; and accumulation of reactor deposits. 77 refs.

Coal liquefaction with synthesis gas

Abstract: Hydroliquefaction is a well-known technique for coal liquefaction. Work with carbon monoxide, however, showed unexpectedly high liquefaction activity and indicated that the presence of both hydrogen and carbon monoxide (as in synthesis gas) could lead to improved liquefaction, particularly for low rank coals. The objective of the work reported here was to develop a better understanding of the chemistry of liquefying coal with synthesis gas plus water and to assess the potential of such a process. The effects of changing gas composition, temperature, pressure, solvents, catalysts and coal types were studied to better understand the process fundamentals and to lay the groundwork for studies in continuous reactors on a larger scale. A variety of coals were converted in batch autoclaves to a low-sulfur fuel oil at temperature of 425 to 450/sup 0/ C and pressures of 2200 to 2400 psig, using 1:1 (H/sub 2/:CO) synthesis gas at reaction times of 30 to 60 minutes at temperature. Although early work suggested that lignites could be readily liquefied without added catalytic agents, later experiments showed that a greatly improved product could be obtained by adding pyrite, which is normally present only in small amounts. Pyrite or, in particular, its reduction product pyrrhotite,more » appear to be important catalysts for coal liquefaction, and, in general, the reactivity of coals correlates well with the pyrite (or iron plus sulfur) content. An important consideration is the optimum temperature for reacting carbon monoxide or its (catalytic) intermediates with coal. This temperature is below 400/sup 0/C, and it is necessary to allow for some reaction time between 380 and 400/sup 0/C. Finally, coal liquefaction with synthesis gas appears to be compatible with the type of processing used to produce Solvent Refined Coal or SRC-II.« less

Novel Separation Processes for Solid/Liquid Separations in Coal Derived Liquids

Abstract: The removal of the mineral matter found in coal derived liquids is a very difficult solid/liquid separation process. Clays, pyrites and other minerals that occur in coal ultimately find their way i...

Predictions of the disposition of select trace constituents in coal gasification processes

Abstract: Many factors may affect the formation and disposition of minor and trace constituents in coal gasification processes, e.g., the coal feedstock, the gasification conditions, and the gas processing conditions. Adequate knowledge of the forms and amounts of these constituents and the controlling factors which dictate their final disposition would be desirable for the complete design of a full scale plant. However, the current data base is weak for some of the more volatile inorganic trace constituents that may be gasified with the coal. In this paper, theoretical projections are made on the amount and final disposition during coal gasification of volatile trace constituents formed from arsenic, boron, lead, selenium, and mercury present in coals. Note that these predictions are theoretical; they are intended to provide insight into what might occur in coal gasification processes, to provide direction for future experimental work for improving the data base on these constituents, and to indicate areas where further investigations would prove useful for the design of full scale processes. The results of these studies indicate that high recoveries of these trace inorganics are to be expected, with low discharge to the environment, in most coal gasification process designs.

Review of supporting research at Oak Ridge National Laboratory for underground coal conversion

Abstract: Chemical and physical properties of lignite, subbituminous coal, bituminous coal, and overburden have been measured in research that began in 1974 at Oak Ridge National Laboratory. Generally, large, monolithic blocks of sample have been dried and pyrolyzed. Thermal data and product yields can be correlated to provide an extrapolation from powder pyrolysis to the pyrolysis steps in underground coal gasification. Significant results of the past year include correlation of block pyrolysis data for low-rank coals, interpretation of mechanisms, and comparison between low-rank and bituminous coals; heating tests of overburden cores from the Hoe Creek field gasification site; and measurement of physical properties, particularly thermal diffusivity and thermal conductivity of low-rank coals. Correlations, mechanisms, and property measurements are reviewed, and applications to underground coal gasification are discussed.