Provided herein is a gasifier, preferably a fixed bed, slagging, updraft oxygen gasification reactor or gasifier with features to facilitate gasification of heterogeneous waste streams producing a syngas with minimal level of condensable tars whilst simultaneously removing molten slag from the bottom of the bed via a cooled slag collector (CSC); syngas and other compositions produced therefrom; and processes including it.

A feedstock delivery system transfers a carbonaceous material, such as municipal solid waste, into a product gas generation system. The feedstock delivery system includes a splitter for splitting bulk carbonaceous material into a plurality of carbonaceous material streams. Each stream is processed using a weighing system for gauging the quantity of carbonaceous material, a densification system for forming plugs of carbonaceous material, a de-densification system for breaking up the plugs of carbonaceous material, and a gas and carbonaceous material mixing system for forming a carbonaceous material and gas mixture. A pressure of the mixing gas is reduced prior to mixing with the carbonaceous material, and the carbonaceous material to gas weight ratio is monitored. A transport assembly conveys the carbonaceous material and gas mixture to a first reactor where at least the carbonaceous material within the mixture is subject to thermochemical reactions to form the product gas.

A feedstock delivery system transfers a carbonaceous material, such as municipal solid waste, into a product gas generation system. The feedstock delivery system includes a splitter for splitting bulk carbonaceous material into a plurality of carbonaceous material streams. Each stream is processed using a weighing system for gauging the quantity of carbonaceous material, a densification system for forming plugs of carbonaceous material, a de-densification system for breaking up the plugs of carbonaceous material, and a gas and carbonaceous material mixing system for forming a carbonaceous material and gas mixture. A pressure of the mixing gas is reduced prior to mixing with the carbonaceous material, and the carbonaceous material to gas weight ratio is monitored. A transport assembly conveys the carbonaceous material and gas mixture to a first reactor where at least the carbonaceous material within the mixture is subject to thermochemical reactions to form the product gas.