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CN-122029138-A - Use of thermal energy from a process for producing cement clinker in operating a stage for separating carbon dioxide (CO 2) from the exhaust gases of the process

CN122029138ACN 122029138 ACN122029138 ACN 122029138ACN-122029138-A

Abstract

The invention relates to the use of thermal energy originating from a process for producing cement clinker, in which process a waste gas rich in carbon dioxide (CO 2 ) is produced.

Inventors

  • Yans Brydenbach
  • Alexander Noch
  • MERSMANN MATTHIAS
  • John Selman
  • Norbert Steinheit

Assignees

  • KHD洪保德韦达克有限公司

Dates

Publication Date
20260512
Application Date
20240925
Priority Date
20231004

Claims (13)

  1. 1. The application of thermal energy is carried out, The thermal energy originates from a process for producing cement clinker, in which process a carbon dioxide (CO 2 ) rich exhaust gas is produced, The thermal energy is used to run a stage for separating carbon dioxide (CO 2 ) from the exhaust gas of the process.
  2. 2. The use of thermal energy according to claim 1, It is characterized in that the method comprises the steps of, The method for producing cement clinker comprises the steps of: preheating the raw meal in a heat exchanger, Calcining the raw meal in a calcination stage and Sintering the calcined green material in a sintering stage, finally -Cooling the sintered cement clinker in a cooling stage, wherein heat energy from the cooling stage is recycled for use in the method.
  3. 3. The use of thermal energy according to claim 2, It is characterized in that the method comprises the steps of, -Extracting thermal energy with a heat exchanger, said heat exchanger A) Is arranged in a tertiary air duct which leads heat energy from the cooling stage to the calcination stage, and/or B) Arranged at the outlet of the heat exchanger for the carbon dioxide rich exhaust gas.
  4. 4. The use of thermal energy according to claim 2 or 3, It is characterized in that the method comprises the steps of, The method comprises the following steps: -a compressed exhaust gas is provided, Introducing the compressed exhaust gas into an absorber (201) as a reactor of a scrubber (200), Injecting a washing liquid into the absorber (201), Transferring the scrubbing liquid from the absorber (201) to a desorber (202) as a further reactor of the scrubber, Heating the washing liquid in the desorber (202), Carbon dioxide (CO 2 ) released during the heating of the washing liquid is discharged, Introducing a scrubbing liquid from the desorber (202) back to the absorber (201), It is characterized in that the method comprises the steps of, The desorber (202) is heated with waste heat from an apparatus for producing cement clinker.
  5. 5. The use of thermal energy according to claim 4, It is characterized in that the method comprises the steps of, The desorber (202) is heated with heat extracted through the heat exchanger (210) and tertiary air duct (150) of the plant for producing cement clinker.
  6. 6. The use of thermal energy according to claim 5, It is characterized in that the method comprises the steps of, The desorber (202) is additionally heated by means of heat extracted by a heat exchanger (211) of an exhaust gas line of the plant for producing cement clinker, wherein the plant for producing cement clinker achieves a sufficiently high exhaust gas temperature for complete regeneration of the absorbent by omitting heat exchange cyclones (114, 115), wherein the number of heat exchange cyclones (114, 115) is between one and four heat exchange cyclones (111, 112, 113, 114), and the selection of the number of exhaust gas temperatures by means of heat exchange cyclones (111, 112, 113, 114) is preferably 360 ℃ to 850 ℃.
  7. 7. The use of thermal energy according to any one of claims 4 or 5, It is characterized in that the method comprises the steps of, The desorber (202) is heated by means of heat extracted by a heat exchanger (212) of an exhaust gas line of the plant for producing cement clinker, wherein the plant for producing cement clinker generates an exhaust gas temperature of more than 800 ℃ by omitting the calciner (120) and the heat exchanger (110) and by using a fluidized bed reactor (121).
  8. 8. The use of thermal energy according to any one of claims 4 to 7, It is characterized in that the method comprises the steps of, Using alkanolamines, such as Monoethanolamine (MEA), diethanolamine (DEA), alkyl alkanolamines, such as Methyldiethanolamine (MDEA) and/or Diglycolamine (DGA), in aqueous solution as absorbent in the absorber (201), or Using ammonia or aqueous ammonia in an organic solvent, or ammonia at low temperature, i.e. below 33 ℃, as absorbent in the absorber (201), and/or Carbonic anhydrase is used as a catalyst in the absorber (201) for accelerating absorption by the absorbent.
  9. 9. An apparatus for producing cement for carrying out the method according to any one of claims 4 to 8, It is characterized in that the method comprises the steps of, A tertiary air duct (150) for guiding hot exhaust gases from the clinker cooler (140) to the calciner (120) has a heat exchanger (210) which guides waste heat for heating the desorber (202).
  10. 10. An apparatus for producing cement for carrying out the method according to any one of claims 4 to 8, It is characterized in that the method comprises the steps of, The cyclone heat exchanger (110) of the plant for producing cement clinker has three heat exchange cyclones (111, 112, 113), whereby the exhaust gas temperature is increased relative to the use of five heat exchange cyclones (111, 112, 113, 114, 115), wherein one heat exchanger (211) directs waste heat from the exhaust gas for heating the desorber (202).
  11. 11. An apparatus for producing cement for carrying out the method according to any one of claims 4 to 8, It is characterized in that the method comprises the steps of, The tertiary air duct (150) for guiding hot exhaust gases from the clinker cooler (140) to the calciner (120) has a heat exchanger (210) which guides waste heat for heating the desorber (202), and the cyclone heat exchanger (110) of the plant for producing cement clinker has three heat exchanging cyclones (111, 112, 113), whereby the exhaust gas temperature is increased relative to the use of five heat exchanging cyclones (111, 112, 113, 114, 115), wherein one heat exchanger (211) guides waste heat from the exhaust gases for heating the desorber (202).
  12. 12. An apparatus for producing cement for carrying out the method according to any one of claims 4 to 8, It is characterized in that the method comprises the steps of, The apparatus has a fluidized-bed reactor (121) in place of the cyclone heat exchanger (110) and the calciner (120), whereby the exhaust gas temperature is increased, wherein the heat exchanger (212) directs waste heat from the exhaust gas for heating the desorber (202).
  13. 13. An apparatus for producing cement for carrying out the method according to any one of claims 4 to 8, It is characterized in that the method comprises the steps of, A tertiary air duct (150) for guiding hot exhaust gases from the clinker cooler (140) to the calciner (120) has a heat exchanger (210) which guides waste heat for heating the desorber (202), and The apparatus has a fluidized-bed reactor (121) in place of the cyclone heat exchanger (110) and the calciner (120), whereby the exhaust gas temperature is increased, wherein the heat exchanger (212) directs waste heat from the exhaust gas for heating the desorber (202).

Description

Use of thermal energy from a method for producing cement clinker in operating a phase for separating carbon dioxide (CO 2) from the exhaust gases of the method Technical Field The invention relates to the use of thermal energy originating from a process for producing cement clinker, in which process a carbon dioxide (CO 2) rich exhaust gas is produced. Background The detrimental effects of artificial carbon dioxide (CO 2) emissions on global climate have been shown in recent decades. The industry sector including cement clinker production facilities as in the past has been the main source of man-made CO 2 emissions. With the growing demand for cement, there is an urgent need for action to reduce the environmental impact of the important industry on carbon dioxide (CO 2) emissions. During the production of cement clinker, calcination of limestone is a critical step, which results in a large emission of carbon dioxide (CO 2) in addition to the release of carbon dioxide (CO 2) from the combustion of fossil fuels, as carbon dioxide (CO 2) is formally thermally driven out of the limestone (calcium carbonate, caCO 3) to obtain quicklime (CaO) for further sintering of quicklime with silicate rock. In order to remove the carbon dioxide (CO 2) from the exhaust gases associated with the production of cement clinker, it is necessary to operate a separator, which requires a large amount of energy to operate. The same applies here both to chemical and physical separations. Amine scrubbing is an example of an energy-intensive separator for carbon dioxide (CO 2) and is a known and effective method for the purification of exhaust gases, in particular in industrial processes which emit exhaust gas components which are harmful to the climate, such as carbon dioxide (CO 2) and sulfur dioxide (SO 2). This involves a chemical absorption process in which an aqueous amine solution is used to remove these harmful substances from the exhaust gas by absorption. The principle of amine scrubbing, an example of an energy intensive separator for carbon dioxide (CO 2), is based on the ability of amine compounds to react with and absorb the acidic components of the exhaust gas, in this case with carbon dioxide (CO 2). In a typical amine scrubbing apparatus, the exhaust gas is directed through a scrubber or absorber where the exhaust gas is contacted with an aqueous amine solution. The amine reacts with the acidic components of the exhaust gas, in this case with carbon dioxide (CO 2), and forms a compound in the form of ammonium carbonate that remains dissolved in solution. As amines, generally alkylamines in aqueous solution are used, such as Monoethanolamine (MEA), diethanolamine (DEA) or Methyldiethanolamine (MDEA) and/or Diglycolamine (DGA). The amine solution containing the separated hazardous material is then directed to a regenerator or desorber. There, the amine solution is heated to release the bound gas. Here, the dissolved ammonium carbonate is again decomposed into carbon dioxide (CO 2) and amine. Carbon dioxide (CO 2) leaks out into the gas space, while the amine remains in the aqueous solution. Amine scrubbing works by selectively transporting carbon dioxide (CO 2) and thus allows for the separation of carbon dioxide (CO 2) from the exhaust gas in pure form. The separated carbon dioxide (CO 2) can either be further processed or safely purged. The amine solution after the carbon dioxide (CO 2) is purified is then directed back to the scrubber or absorber to continue the purification process. The task of the amine solution is therefore to selectively transport carbon dioxide (CO 2) and the amine solution remains in the circulation inside the washing process. As an example of an energy intensive separator for carbon dioxide (CO 2), amine scrubbing has several advantages as an exhaust gas purification technique. Amine scrubbing enables a high degree of separation for carbon dioxide (CO 2) and also for sulfur dioxide (SO 2), which helps reduce greenhouse gas emissions and air pollution. In addition, amine scrubbing also allows for some removal of other harmful substances, such as nitrogen oxides (NO X) and Volatile Organic Compounds (VOCs). The method is also relatively flexible and can be adapted to different exhaust gas compositions and volumes. However, amine scrubbing also presents challenges as an example of an energy intensive separator for carbon dioxide (CO 2). The use of amines as solvents involves an energy intensive regeneration process. Although the absorption process is an exothermic process and proceeds spontaneously during the amine scrubbing, the subsequent separation of the exhaust gas, here carbon dioxide (CO 2), from the amine used for scrubbing is an endothermic process which must be energized. In order to release the absorbed carbon dioxide (CO 2) from the absorbent, the so-called "desorption", it is necessary either to lower the pressure above the absorbent and/or to raise the temperature of the absorbent, wh