Abstract:
An improved process is disclosed for the production of fuel gas such as synthetic natural gas from coal. A sized coal feed of larger particle size is gasified in a moving bed gasifier such as the British Gas/Lurgi slagging gasifier, and forms a methane rich synthesis gas containing heavy and light organics which is quenched to form a water phase containing dissolved phenolic and other compounds. The water phase is separated from the gas phase and insoluble organics and mixed with a second portion of the coal containing fine particles which are not suitable for moving bed gasification to form a slurry. This coal-phenolic water slurry is gasified in an entrained bed gasifier, for example, the Texaco partial oxidation process, and forms a methane lean synthesis gas. The phenol, ammonia and dissolved organics in the water phase are destroyed and converted to valuable product gas. At least part of this product gas may be blended with the moving bed product gas for further processing to produce the desired fuel gas product. The product gas from the entrained bed gasifier is also suitable for production of hydrogen, ammonia, or methanol.
Abstract:
A gasification process in which gasification of lump size gas producing material, such as coal, is carried out under high pressure on a fixed-bed principle with a continuous feed of coal particles thereto, the continuous feed being accomplished by feeding coal of an appropriate particle size range into a volume of liquid within a first confinement path through a free surface thereof exposed to atmospheric conditions, collecting successive incremental volumes of particles and entrained liquid and transferring them into a liquid within a second circuitous confinement path maintained under pressure by virtue of the exposure of the free surface of a volume thereof with the gasification pressure conditions, conveying the particles of the incremental volumes communicated with the second path through a pumping action upstream of the particle communication therewith, collecting the particles in the volume and moving them upwardly through the free surface thereof into the gasification zone.
Abstract:
A process for disposing of sanitary sewage sludge by producing a pumpable slurry of sewage sludge with or without solid carbonaceous fuel and burning said slurry as fuel in a partial oxidation gas generator, furnace, or boiler. The aqueous slurry of sewage sludge is concentrated by removing water by means of a conventional belt filter press, centrifuge, or hydroclone. The dewatered slurry of sewage sludge is preheated and sheared; hydrothermally treated; and its solids content increased. A chelating agent, for example an aminopolycarboxylic acid or a hydrocarboxylic acid is mixed with the aqueous slurry of sewage sludge during the preheating and shearing step and/or the step for increasing its solids content. By means of the subject process, the viscosity of the slurry of sewage sludge with or without solid carbonaceous fuel is reduced and coagulation is suppressed. A pumpable aqueous slurry of sewage sludge with or without solid carbonaceous fuel is produced and burned with a free-oxygen containing gas in a partial oxidation gasifier, furnace, boiler, or incinerator to produce a hot raw effluent gas stream. In a preferred embodiment, the effluent gas stream is cleaned and purified and non-contaminating ash and slag are separated. By this process, noxious sewage sludge may be disposed of without contaminating the environment. By-product synthesis gas, reducing gas, or fuel gas may be produced.