Patent ID: 6254382
Filing Date: 2001-07-03
Classification: C04B

Abstract:
A method for thermal treatment of mealy raw materials, in particular in the manufacturing of cement clinkers from raw meal, comprising the steps:thermally treating raw meal in a burning process by pre-heating the raw material in a cyclone suspension gas pre-heating system having a series of cyclones, calcinating the preheated material in a gas-solid material suspension within a calcinator having an ascending branch and a descending branch, sintering the calcinated material in a rotary kiln which produces an exhaust gas stream directed into a rotary kiln exhaust gas line, and cooling the sintered material in a clinker cooler with an outgoing air stream directed into a cooler outgoing air line,using the exhaust gas stream from the rotary kiln and the outgoing air stream of the clinker cooler in the calcinator, supplied with fuel, for the calcination of the raw meal,diverting the gas-solid material suspension in the calcinator and introducing said suspension into a lowest cyclone of the cyclone suspension gas pre-heating system for the purpose of separating the calcinated material from the gas stream,directing the rotary kiln exhaust gas line into a first portion of the calcinator,directing the cooler outgoing air line into a separate, second portion of the calcinator,introducing fuel and the preheated raw material into the first and second portions of the calcinator at respective combustion points,burning the fuel in the first and second portions of the calcinator sub-stoichiometrically to form CO strands for the reduction of NO.sub.x both in the first portion of the calcinator and in the second portion of the calcinator,introducing additional combustion air into the calcinator downstream of the point of introduction of the fuel in the first and second portions of the calcinator and therewith burning a remainder of the CO strands.