| 摘要 |
<p>In gasification of coal to produce CO and H2 (A) coal is crushed, then elutriated to separate coal fines and coarse particles, (b) the fines are scrubbed with water to form a slurry, (c) a 1st stream of coal, consisting at least partly of the slurry, is burned without bed formation in presence of water under oxidn. conditions, to produce gases contg. CO2 and steam, and (d) a 2nd stream of coal, consisting at least partly of the coarse particles from (a), is fluidised in a separate zone by the CO2 and steam from the combustion zone, to produce CO and H2. The CO + H2 may be used as fuel, as reducing gas in metallurgy or chemical processes for conversion to H2, in petroleum refineries and in coal conversion plants. There is little pollution and no water effluent is product. The water used may be polluted water from other processes. Ash is removed in oxidised from as solidified slag, suitable for landfil or mineral recovery. Gaseous impurities are destroyed in the process, or converted to useful forms, e.g. S cpds. are converted to H2S, from which S can be recovered; N cpds. are converted to NH3, which is recovered, or to N2. The process is economical in use of heat. High-S, high-ash by-prods. or wastes from other processes, e.g. from a solvent coal liquefaction can be used as raw material. The operation is safe, since there is a fluidised bed of coal char between the O2 injection zone and the combustible gas.</p> |
