Method and system for producing cement clinker from raw cement mixture
The invention relates to a method and a system for producing cement clinker from raw cement mixture, wherein one part of the raw cement mixture is preheated in a calciner preheater, and the other part of the raw cement mixture is preheated in an oven preheater, the preheated raw cement mixture is pre-calcined in a calciner which is operated according to the oxyfuel method, the pre-calcined raw cement mixture is fired in an oven, the fired raw cement mixture is cooled in a cooler, the calciner preheater is operated using exhaust gases of the calciner, the oven preheater is operated using exhaust gases of the oven, an entrained flow reactor is used as the calciner, a part of the calciner exhaust gas being recirculated to the calciner after being used in the calciner preheater, and the oven exhaust gas undergoes a post-combustion CO 2 separation.
1. A process for producing cement clinker from cement raw meal, comprising:
a. part of the cement raw meal is preheated in a calciner preheater and the other part of the cement raw meal is preheated in a furnace preheater;
b. the cement raw meal which has been preheated in the calciner preheater and in the furnace preheater is precalcined in a calciner operated by the oxy-fuel process;
c. the precalcined cement raw meal is fired in a furnace;
d. the fired cement raw meal is cooled in a cooler;
e. the calciner preheater is operated using calciner exhaust gases from the calciner; and
f. the furnace preheater is operated using furnace exhaust gases from the furnace;
g. an entrained flow reactor is used as calciner, with a part of the calciner exhaust gas being, after having been utilized in the calciner preheater, recirculated to the calciner; and
h. the furnace exhaust gas is subjected to a post-combustion removal of CO 2 , wherein a heat requirement for the post-combustion removal of CO 2 is covered by the waste heat from an unrecirculated part of the calciner exhaust gas, of the furnace exhaust gas and/or of an exhaust gas from the cooler.
2. The process of claim 1 , wherein the part of the calciner exhaust gas which is recirculated to the calciner is heated by exhaust gases from the cooler.
3. The process of claim 1 , wherein the heat requirement for the post-combustion removal of CO 2 is partly covered by the waste heat of the unrecirculated part of the calciner exhaust gas after utilization in the calciner preheater.
4. The process of claim 1 , wherein the heat requirement for the post-combustion removal of CO 2 is partly covered by the waste heat of the furnace exhaust gas after utilization in the furnace preheater.
5. The process of claim 1 , wherein the calciner exhaust gas after utilization in the calciner preheater and/or the furnace exhaust gas after utilization in the furnace preheater is fed to a waste heat boiler for generating process steam, with the process steam generated being used in the post-combustion removal of CO 2 .
6. The process of claim 1 , wherein the unrecirculated part of the calciner exhaust gas is subjected to a removal of CO 2 by way of CO 2 liquefaction and a CO 2 -containing residual stream formed here is subjected together with the furnace exhaust gas to the post-combustion removal of CO 2 .
7. The process of claim 1 , wherein the oxy-fuel process and the post-combustion removal of CO 2 are matched to one another in such a way that the process heat available for the post-combustion removal of CO 2 from the at least one part of the calciner exhaust gas, the furnace exhaust gas and/or an exhaust gas from the cooler is completely utilized.
8. The process of claim 7 , wherein an excess of process heat is compensated by a decrease in an existing deficiency of process heat by means of increasing the degree of calcination in the calciner and the preheater thereof.