Abstract:
In a coal liquefaction process an aqueous slurry of coal is prepared containing a dissolved liquefaction catalyst. A small quantity of oil is added to the slurry and then coal-oil agglomerates are prepared by agitation of the slurry at atmospheric pressure. The resulting mixture of agglomerates, excess water, dissolved catalyst, and unagglomerated solids is pumped to reaction pressure and then passed through a drainage device where all but a small amount of surface water is removed from the agglomerates. Sufficient catalyst for the reaction is contained in surface water remaining on the agglomerates. The agglomerates fall into the liquefaction reactor countercurrently to a stream of hot gas which is utilized to dry and preheat the agglomerates as well as deposit catalyst on the agglomerates before they enter the reactor where they are converted to primarily liquid products under hydrogen pressure.
Abstract:
In a coal liquefaction process an aqueous slurry of coal is prepared containing a dissolved liquefaction catalyst. A small quantity of oil is added to the slurry and then coal-oil agglomerates are prepared by agitation of the slurry at atmospheric pressure. The resulting mixture is drained of excess water and dried at atmospheric pressure leaving catalyst deposited on the agglomerates. The agglomerates then are fed to an extrusion device where they are formed into a continuous ribbon of extrudate and fed into a hydrogenation reactor at elevated pressure and temperature. The catalytic hydrogenation converts the extrudate primarily to liquid hydrocarbons in the reactor. The liquid drained in recovering the agglomerates is recycled.
Abstract:
Finely divided, clean coal or other carbonaceous material is provided by forming a slurry of coarse coal in aqueous alkali solution and heating the slurry under pressure to above the critical conditions of steam. The supercritical fluid penetrates and is trapped in the porosity of the coal as it swells in a thermoplastic condition at elevated temperature. By a sudden, explosive release of pressure the coal is fractured into finely divided particles with release of sulfur-containing gases and minerals. The finely divided coal is recovered from the minerals for use as a clean coal product.
Abstract:
A carbonaceous material such as coal is conditioned by contact with a supercritical fluid prior to physical beneficiation. The solid feed material is contacted with an organic supercritical fluid such as cyclohexane or methanol at temperatures slightly above the critical temperature and pressures of 1 to 4 times the critical pressure. A minor solute fraction is extracted into critical phase and separated from the solid residuum. The residuum is then processed by physical separation such as by froth flotation or specific gravity separation to recover a substantial fraction thereof with reduced ash content. The solute in supercritical phase can be released by pressure reduction and recombined with the low-ash, carbonaceous material.
Abstract:
This invention comprises a method of achieving a highly efficient use of catalyst in conducting hydrogenation reactions of hydrocarbons in the liquid state by means of solid catalysts. The catalyst is wholly contained in a microporous layer no thicker than 200 microns deposited on the outside surface of otherwise inert support particles. The catalyst particles, of the order of 10 mm diameter, are contained in a fixed, vertical, packed bed, and are brought into contact with the liquid hydrocarbon and hydrogen by passing the two fluids in cocurrent flow, either upwards or downwards, through the bed at substantially greater gas velocities than are usually employed in fixed bed catalytic reactors used for hydrogenating hydrocarbons in the liquid state. The effect of the high gas velocity is to achieve substantially higher heat and mass transfer rates among the three phases (catalyst, liquid hydrocarbon, and gaseous hydrogen) than are achievable under conventional conditions of operation of fixed bed catalytic reactors used for hydrogenating hydrocarbons in the liquid state. The combined effects of the high gas velocity and the mode of deposition of the catalytically active components on the catalyst support, are the achievement of a large global reaction rate in the reactor, combined with a high internal effectiveness factor for the catalyst. For fast hydrogenation reactions, for which the invention is most advantageously employed, a comparable efficiency of catalyst utilization can at present be achieved only by using catalyst in the form of powder or granules so small as to preclude their use in a fixed bed reactor.