Fluidised bed reactor and method of operating such a reactor.

摘要

A substantially enclosed circulating fluidised bed reactor (1) comprises a substantially upright reactor chamber (10) containing a fluidised bed (11) of granular material and a substantially upright and cylindrical cyclonic reactor vessel (20) adjacent to the chamber, the respective upper regions (16, 18) of the chamber and the vessel being connected via a conduit (14) and the respective lower regions of the chamber and the vessel being operatively connected. The vessel (20) has a cylindrically shaped exit throat (21) aligned substantially concentrically with it at its top. Operation of the reactor comprises feeding matter to be reacted into the chamber (10); supplying a first stream of pressurised air or other gas to the reactor through a plurality of openings (12) at the bottom of the chamber (10) at a sufficient velocity to fluidise the granular material and the matter in the circulating regime for reacting a minor portion of the matter in the chamber, whereby a substantial portion of the granular bed material, reaction product gases and unreacted matter are continually entrained out of the chamber and into the cyclonic reactor vessel (20) via the conduit (14); tangentially supplying a second stream of pressurised air into the vessel (20) through a plurality of openings (19) in the cylindrically shaped interior side wall of the vessel for cyclonic reaction of a major portion of the matter in the vessel, the second stream being supplied, and the vessel being constructed and operated, so as to produce a Swirl number of at least about 0.6 and a Reynolds number of at least about 18,000 within the vessel for creating a cyclone of turbulence therein having at least one internal reverse flow zone, thereby increasing the rate of combustion therein; permitting the reaction product gases generated in the reactor to exit from the reactor via the exit throat (21) while retaining substantially all of said granular material and unreacted matter within the reactor; collecting the granular bed material and any unreacted matter in the lower region of the vessel (20) and returning it to the lower region of the chamber (10) and controlling the reaction process in the reactor by controlling the flow of the first and second streams of air and by controlling the flow of granular bed material and matter to be reacted in the chamber and the vessel.