Patent ID: 8617506

Claim:
A method for recovering CO 2 gas generated in a cement manufacturing plant, the method comprising: maintaining an inside of a mixer/calciner at at least a calcination temperature of a pre-calcination cement material by superheating the pre-calcination cement material extracted from a first preheater to at least the calcination temperature in a superheating furnace, to give a superheated cement material; and then feeding the superheated cement material to the mixer/calciner and mixing the superheated cement material with a new pre-calcination cement material that is extracted from the first preheater and fed to the mixer/calciner; and calcining the pre-calcination cement material in the mixer/calciner, to give calcined cement material, and then again returning the calcined cement material to the superheating furnace so as to repeat circulation to the mixer/calciner, and to recover CO 2 gas generated in the mixer/calciner; and feeding a part of the calcined cement material to a cement kiln, wherein the method recovers recover CO 2 gas generated in the cement manufacturing plant, and, in the cement manufacturing plant, the pre-calcination cement material is preheated by the first preheater and is then fed and burned in the cement kiln having a high temperature atmosphere therein, wherein the pre-calcination cement material extracted from the first preheater and the new pre-calcination cement material preheated by a second preheater, provided independently of the first preheater, are fed to the mixer/calciner, and CO 2 gas generated in the mixer/calciner is recovered after being employed as a heat source of the second preheater.