A process provides for reducing agglomerate formation during thermal decomposition of a carbonaceous material feedstock. A non-catalytic thermal decomposition process includes providing generally solid feedstock to a thermal decomposition unit and moving the feedstock through at least one gasification zone in the thermal decomposition unit with a moving device. The process includes providing oxygen and optionally an additional gas to the gasification zone. In one aspect, the process includes moving feedstock through the gasification zone and providing oxygen to the gasification zone at rates effective for maintaining a material bed temperature not exceeding about 2300° F. at any point in the material bed, and for maintaining a material bed temperature of about 500° F. to about 2000° F.