Method for manufacturing cement clinker and cement plant

2:

• The method according to claim 1, wherein an oxygen concentration from 1 to 3 Vol.-% dry is adjusted in the calciner.

3:

• The method according to claim 1, wherein the calciner exhaust gas is purified in a calciner exhaust gas cleaning unit and/or a carbon dioxide purification unit.

4:

• The method according to claim 3, wherein the calciner exhaust gas is subjected to compression in the carbon dioxide purification unit.

6:

• The method according to claim 1, wherein kiln off-gas is cleaned by passing through a mill for grinding raw materials to provide the raw meal and/or a raw material feed.

7:

• The method according to claim 6, wherein kiln off-gas is dedusted and/or NO and NO2 contained are reduced in the presence of NH3 or a compound releasing NH3 in a catalytic or non-catalytic reactor, and/or volatile organic compounds contained are burned down to CO2 and/or SOx contained is adsorbed on the raw meal during preheating, adsorbed on a raw material when drying it and/or scrubbed from the gas with a scrubbing device.

8:

• The method according to claim 1, wherein the oxygen fed to the calciner is preheated to a temperature of ≥100° C.

9:

• The method according to claim 1, wherein oxygen fed to the calciner has an O2 concentration ≥80 Vol.-%.

10:

• A cement manufacturing plant comprising a first cyclone preheater having a raw meal feed and adapted to receive off-gas from a rotary kiln, a second cyclone preheater adapted to receive partially preheated raw meal from the first preheater and recirculated exhaust gas as well as precalcined raw meal from a calciner, wherein the calciner is a circulating fluidized bed reactor and the calciner is arranged to receive preheated raw meal and a recirculated part of the precalcined raw meal from the cyclone preheater and adapted to precalcine the preheated raw meal, a rotary kiln adapted to receive precalcined raw meal via the second cyclone preheater from the calciner for converting the precalcined raw meal into cement clinker by sintering and to pass the cement clinker to a clinker cooler, and an oxygen supply arranged to provide oxygen to the calciner, wherein a combustion atmosphere inside the calciner is made up of oxygen from an oxygen supply and recirculated exhaust gas from the calciner, and wherein the plant comprises a carbon dioxide purification unit adapted to capture carbon dioxide from the exhaust gas from the calciner.

11:

• The cement manufacturing plant according to claim 10, wherein the plant comprises means for preheating the oxygen to a temperature of ≥100° C.

12:

• The cement manufacturing plant according to claim 10, wherein the oxygen supply is adapted to feed the oxygen to a calciner burner without dilution by recirculated exhaust gas.

14:

• The cement manufacturing plant according to claim 10, wherein the plant additionally comprises a kiln off-gas cleaning unit and/or a carbon dioxide capture system.

15:

• The cement manufacturing plant according to claim 11, wherein the oxygen fed to the calciner is preheated by heat exchange with recirculated calciner exhaust gas in a heat exchanger to a temperature from 300 to 400° C.

16:

• The method according to claim 4, wherein the calciner exhaust gas is subjected to one or more of the following steps in the carbon dioxide purification unit:
• cooling, drying, filtration, and/or cryogenic distillation.

17:

• The method according to claim 8, wherein the oxygen fed to the calciner is preheated by heat exchange with recirculated calciner exhaust gas in a heat exchanger to a temperature from 300 to 400° C.

18:

• The method according to claim 9, wherein the oxygen fed to the calciner has an O2 concentration of ≥90 Vol.-%.

19:

• The method according to claim 9, wherein the oxygen fed to the calciner has an O2 concentration of ≥99 Vol.-%.