Pyrolysis process

Abstract

In a process for recovery of values contained in solid carbonaceous material, a solid carbonaceous material is comminuted and then treated at an elevated temperature in a pretreatment zone with a first capping agent which is at treating conditions either a liquid or a gas. The treating conditions are such that the first capping agent is sorbed by the solid particulate carbonaceous material. The solid particulate carbonaceous material containing the sorbed first capping agent is then subjected to pyrolysis in the presence of a second capping agent, and preferably in the presence of a solid particulate source of heat and a transport gas in a transport flash pyrolysis reactor, to form a pyrolysis product stream. The solid particulate carbonaceous feed material is pyrolyzed and newly formed volatilized hydrocarbon free radicals are substantially simultaneously terminated by the sorbed first capping agent, or the second capping agent as such radicals are formed, to form a pyrolysis product stream. The pyrolysis product stream contains a gaseous mixture and particulate solids which are separated from the gaseous mixture to form a substantially particulate solids-free gaseous mixture stream which contains capping agent terminated volatilized hydrocarbon free radicals, hydrogen depleted capping agents, pyrolysis product vapors and a transport gas. Hydrocarbons of four or more carbon atoms in the gaseous mixture stream are condensed. A liquid stream containing the stabilized liquid product is then treated or separated into various fractions. A liquid containing the hydrogen depleted capping agents is hydrogenated to form regenerated capping agents, at least a portion of which is recycled to the pretreatment zone and at least another portion is recycled to the pyrolysis zone. In another embodiment the capping agents are produced by the process, separated from the liquid product mixture, and recycled.