A process and apparatus for producing pure hydrogen from a syngas generated by the high temperature gasification of municipal, agricultural or industrial derived wastes. The process is able to make pure hydrogen to be further reacted with nitrogen to make ammonia and urea.

The disclosure relates to a rotary kiln catalytically enhanced oxy-fuel gasification and oxy-fuel combustion system—power plant including an air separation unit arranged to separate oxygen from air and produce a stream of substantially pure liquid oxygen; rotary kiln gasifiers to convert municipal solid waste, biomass, alternate wastes, coal, or hydrocarbon fuels into a synthesis gas in the presence of oxygen, carbon dioxide, high temperature steam and lime catalysts; an oxy-fuel fired boiler arranged to combust synthesis gas, in the presence of substantially pure oxygen gas, to produce an exhaust gas comprised of water and carbon dioxide; and a carbon dioxide removal unit arranged to recover carbon dioxide gas from the exhaust gas, recycle a portion of the recovered carbon dioxide gas for use in the rotary kiln gasifier, and liquefy the remainder of the recovered carbon dioxide gas for removal from the plant. In this new plant, the carbon dioxide removal unit is thermally integrated with the air separation unit or alternately the liquid oxygen storage and supply system by directing a stream of liquid oxygen to the carbon dioxide removal unit to liquefy the recovered carbon dioxide gas, the liquid oxygen thereby evaporating and forming cold oxygen gas which is heated prior to consumption in the rotary kiln and oxy-fuel fired boiler.

A raw syngas coming from HT gasification of organic wastes, once cooled in a proper heat recovery boiler or in a quencher is treated in a scrubbing section where, by adding an acidic solution followed by alkaline solution and by a WESP, particulate and chlorine compounds are removed and the syngas is ready for conversion, after its compression. In the conversion step CO is converted into C02 and H2 by adding steam; H2S is reduced to sulphur in a solid form, C02 is removed via cryogenic unit or an amine unit and pure H2 is produced.

A method of removing impurities from black water associated with a gasifier includes adding a flocculant to the black water to create a black water and flocculant mixture, settling the black water and flocculant mixture in a gravity settling device to separate the black water and flocculant mixture into clarified water, a froth phase, and a heavy phase, the froth phase comprising soot, water, and air or gas, the heavy phase comprising soot and water, drawing off the clarified water from the settled black water and flocculant mixture, collecting a dilute slurry comprising the froth phase and the heavy phase, and phase separating the dilute slurry in a high-speed centrifuge to provide additional clarified water and a concentrated slurry, wherein the black water is obtained from wet gas scrubbing of syngas.