Showing papers on "Carbochemistry published in 1977"

Characterization of mineral matter in coals and coal liquefaction residues. Annual report

Abstract: One of the major aims of this program is to characterize organic and mineral components of coals and coal liquefaction residual materials. Relationships are sought between composition and properties of these components and the behavior of specific coals during liquefaction processes. Results show that the residual materials are made up of various organic and inorganic components. The organic phase of these materials is comprised of unaltered or partly reacted coal macerals and carbonaceous slids formed by retrogressive reactions during processing. Inorganic components are coal minerals, pyrrhotite and, in the case of liquefaction and subbituminous Wyodak coal, calcium carbonate precipitates. The exact distribution of all these components is a function of feed coal, and processng conditions (H-Coal or Solvent Refining). Studies have been made into factors which influence retrogressive reactions during Solvent Refining. In the absence of a hydrogen donor, short contact times SRC's form semi-coke more readily than do equivalent long contact time SRC's. Experiments with SRC fractions show that the propensity to undergo retrogressive reactions is strongly influenced by phenolic oxygen functionality and molecular weight. Semi-coke formation is markedly inhibited by hydrogen transfer either by added hydrogen donors or compounds which can shuttle hydrogen. The techniques developed by thismore » project have potential as a means of diagnosing problems or inefficiencies in plant or equipment operation.« less

Process for coal gasification

Abstract: The efficiency of conversion of coal in the coal-gasification process is increased by pre-treatment of the coal to increase the fluid-permeability thereof. The reagent used for increasing the coal permeability is recoverable in high yield. Pre-treatment of bituminous coal by this process makes it possible to gasify coals of this rank effectively, such coals previously having been gasifiable only at low conversion efficiencies. Pre-treatment with a permeability-enhancing reagent is also useful as a step in the process of dissolving coal.

Process for the isolation of chemicals from processed coals

Abstract: Processed coal such as solvent refined coal are subjected to multistage liquid chromatographic fractionation. There is employed a succession of eluants of progressively varying properties, this succession having the effect of removing from the substrate a corresponding succession of sharply defined, chemically differentiated product groups each of value as an industrial raw material. An installation for practising the invention on a continuous basis is described.

Nature and origin of asphaltenes in processed coals: the chemistry and mechanisms of coal conversion to clean fuel. Annual report, March 1976--February 1977

Abstract: Studies have been undertaken to develop a fundamental understanding of the chemistry and structure of coal and coal products and the mechanisms involved in the conversion of coal to soluble products under typical solvent refining conditions Illinois, Kentucky, and Wyoming coals were investigated Reactions were conducted in stirred autoclaves at contact times from 025 to 420 min using synthetic recycle solvents Reaction variables included particle size, coal preparation method, temperature, atmosphere, and solvent composition Products were characterized in detail utilizing newly developed liquid chromatographic methods Fractions were further characterized by wet chemical, polarographic, and a variety of spectroscopic techniques, and skeletal structures of SRC's and parent coals were derived The chemistry of typical recycle solvents was studied Systematic changes which occur during the transformation of coal into soluble and upgraded products were studied in detail Compositional changes monitored included aromatic contents and skeletal structure, and changes in functionality, molecular weight, and elemental composition Elucidation of the kinetics and mechanisms of functionality changes was aided by an extensive study of the chemistry of isolated SRC fractions and of model compounds under liquefaction conditions

Process for the preparation of synthetic coking coal

Abstract: Synthetic coking coal is prepared by mixing solvent refined coal with coal and heat-treating the resulting mixture at a temperature ranging from about 300° C to about 480° C, preferably from about 380° C to about 450° C.