SOLIDS CIRCULATION SYSTEM AND METHOD FOR CAPTURE AND CONVERSION OF REACTIVE SOLIDS WITH FLUIDIZED BED TEMPERATURE CONTROL

摘要

A solids circulation system receives a gas stream containing char or other reacting solids from a first reactor. The solids circulation system includes a cyclone configured to receive the gas stream from the first reactor, a dipleg from the cyclone to a second reactor, and a riser from the second reactor which merges with the gas stream received by the cyclone. The second reactor has a dense fluid bed and converts the received materials to gaseous products. A conveying fluid transports a portion of the bed media from the second reactor through the riser to mix with the gas stream prior to cyclone entry. The bed media helps manipulate the solids that is received by the cyclone to facilitate flow of solids down the dipleg into the second reactor. The second reactor provides additional residence time, mixing and gas-solid contact for efficient conversion of char or reacting solids.

主权项

1. A system for processing a carbonaceous feedstock to create a final product gas stream, comprising:
(a) a first reactor (500) having a fluidized bed and configured to receive a feedstock and steam, and output a syngas stream (600) via a first conduit (602), the syngas stream (600) comprising syngas, char, condensable organic compounds and aromatic hydrocarbons; (b) a second conduit (612) connected to the first conduit (602), the second conduit (612) configured to receive a portion of said syngas stream (600) as a first-stage product gas stream (610); (c) a second reactor (100) having a fluidized bed and configured to receive char from the syngas stream (600) and an oxygen containing gas, the second reactor configured to operate under conditions sufficient to convert the char into a second-stage product gas stream (910) containing at least carbon monoxide; and (d) a cooling pipe (180) protruding into the fluidized bed in the second reactor (100) to control bed operating temperature, the cooling pipe being connected to a source of elevated pressure steam as a coolant; wherein: the second reactor and the second conduit (612) are connected such that the second-stage product gas stream (910) is merged with the first-stage product gas stream (610) to form the final product gas stream (950); and the second reactor is configured to operate such that the cooling pipe superheats the elevated pressure steam.