| 摘要 |
<p>1479257 Coal gasification COGAS DEVELOPMENT CO 16 Sept 1975 [23 Sept 1974] 38023/75 Heading C5E A process for the production of a combustible gas comprises pyrolysing coal at a temperature below 700‹ C. to form aqueous vapours and a char, condensing the aqueous vapours to produce an oil and waste water, and vaporizing the waste water to provide steam which is fed to a gasification zone in which the char is gasified to give the desired product gas. If desired, water may be condensed from the effluent gas from the char gasification zone and combined with the waste water before vaporizing. The water may be vaporized using a pebble heater or may be flashed into a stream of superheated steam fed to the gasification zone. The preliminary distillation may be performed in a series of fluidized beds, the fluidizing medium being a stream of the crude synthesis gas from the gasification zone. The gasification may also be performed in a fluidized bed of char heated by combustion gases produced externally of the gasification zone. The crude synthesis gas may be combined with the gases obtained from the preliminary distillation and subjected to shift conversion over a zinc oxide catalyst followed by a recycling methanation step.</p> |
