Patent attributes
The present invention relates to processes and continuous processes for preparing gaseous products, and in particular, methane via the catalytic gasification of carbonaceous feedstocks in the presence of steam. In one aspect of the invention, the processes comprise at least partially combusting a first carbonaceous feedstock with an oxygen-rich gas stream, a recycle steam stream, and an aqueous make-up stream in an oxygen-blown gasifier, under suitable temperature and pressure, to generate a first gas stream comprising hydrogen, carbon monoxide and superheated steam; and reacting a second carbonaceous feedstock and the first gas stream in a catalytic gasifier in the presence of a gasification catalyst under suitable temperature and pressure to form a second gas stream comprising a plurality of gaseous products comprising methane, carbon dioxide, hydrogen, carbon monoxide and hydrogen sulfide. The processes can comprise using at least one catalytic methanator to convert carbon monoxide and hydrogen in the gaseous products to methane and in certain embodiments do not recycle carbon monoxide or hydrogen to the gasifier. Heat energy recovered from the catalytic gasification can be used to generate the recycle steam stream.
