Process and a plant for the production of portland cement clinker

• US 20040129181A1
• Filed: 10/14/2003
• Published: 07/08/2004
• Est. Priority Date: 04/13/2001
• Status: Active Grant

• Current Assignee: CO2 Solutions Inc.
• Original Assignee: CO2 Solutions Inc.
• Inventors: Lalande, Jean-Marie, Tremblay, Anne
• Granted Patent: US 6,908,507 B2
• Time in Patent Office: Days
• US Class Current: 106/739
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/84 Biological processes
• CPC Class Codes: C04B 2103/0001 Living organisms, e.g. microorganisms, or enzymes
• CPC Class Codes: C04B 7/365 by extracting part of the material from the process flow and returning it into the process after a separate treatment, e.g. in a separate retention unit under specific conditions
• CPC Class Codes: C04B 7/367 Avoiding or minimising carbon dioxide emissions
• CPC Class Codes: C04B 7/436 Special arrangements for treating part or all of the cement kiln dust
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 40/121 Energy efficiency measures, e.g. improving or optimising the production methods
• CPC Class Codes: Y02P 40/18 Carbon capture and storage [CCS]

Abstract

A process is disclosed for producing cement clinker, comprising the steps of: a) providing a mixture of ground calcareous materials and ground argillaceous materials; b) heating the mixture of step a) to a temperature sufficient to calcine and fuse the ground materials to form the cement clinker, and thereby producing an exhaust gas containing CO₂; c) catalysing the hydration of at least a portion of the CO₂ contained in the exhaust gas and producing a solution containing bicarbonate ions and hydrogen ions; and d) adding to the solution obtained in step c) metal ions, and adjusting the pH of the solution to precipitate a carbonate or said metal. Preferably, the metal ions are Ca⁺⁺ obtained from the dissolution of a material selected from the group consisting of CaCl₂, cement kiln dust and sea salts and the carbonate is CaCO₃ which is advantageously recycled into the process by adding the CaCO₃ to the mixture of step a). A cement plant for performing this process is also disclosed.

Claims

1. A process for producing cement clinker, comprising the steps of:

a) providing a mixture of ground calcareous materials and ground argillaceous materials;

b) heating the mixture of step a) to a temperature sufficient to calcine and fuse the ground materials to form the cement clinker, and thereby producing an exhaust gas containing CO₂;

c) catalysing the hydration of at least a portion of the CO₂ contained in the exhaust gas and producing a solution containing bicarbonate ions and hydrogen ions; and

d) adding to the solution obtained in step c) metal ions, and adjusting the pH of the solution to precipitate a carbonate of said metal.

2. A process as claimed in claim 1, wherein said hydration is performed in the presence of an enzyme capable of catalysing the hydration of dissolved CO₂ into hydrogen ions and bicarbonate ions.

3. A process as claimed in claim 1 wherein, the metal ions are Ca++ and the carbonate is CaCO₃.

4. A process as claimed in claim 3, comprising, after step d), the step of:

e) recycling the CaCO₃ obtained in step d) into the process by adding the CaCO₃ to the mixture of step a).

5. A process as claimed in claim 2, wherein the enzyme used in step c) is carbonic anhydrase or an analogue thereof.

6. A process as claimed in claim 5, wherein step c) comprises the steps of

feeding liquid H₂O and at least a portion of the exhaust gas into a bioreactor containing therein a reaction chamber filled with said carbonic anhydrase immobilized on a support.

7. A process as defined in claim 3, wherein the ions Ca++ are obtained from the dissolution of a material selected from the group consisting of CaCl₂, cement kiln dust and sea salts.

8. A process as defined in claim 1, wherein the calcareous materials are selected from the group consisting of limestone, marine shells and marl.

9. A process as defined in claim 1 wherein the argillaceous materials are selected from the group consisting of clay, slate, sand, shale, and blast-furnace slags.

10. A process as claimed in claim 1, wherein the mixture of step a) further comprises one or more material selected form the group consisting of aluminium, iron and chemical admixture.

11. A process as claimed in claim 1, wherein the metal ions is selected from the group consisting of Ca++, Mg++, Ba++, CaMg++ and Na+.

12. A process as claimed in claim 1, comprising, prior to step c) of hydration, the step of:

cleansing the exhaust gas for removing waste particles.

13. A process as claimed in claim 1, wherein said temperature sufficient to calcine and fuse the ground materials is at least 1400°

C.

14. A plant for producing cement clinker, comprising:

a kiln for burning raw materials suitable for producing cement clinker, the kiln having an inlet for receiving the raw materials, an outlet for discharging the cement clinker and a gas outlet for discharging an exhaust gas containing CO₂;

means for catalysing the hydration of the CO2 contained in the exhaust gas into bicarbonate ions and hydrogen ions;

means for reacting the bicarbonate ions with metal ions to precipitate the carbonate of said metal.

15. A plant as claimed in claim 14, wherein said metal ions are Ca++ and the carbonate is CaCO₃ and wherein the plant further comprises:

means for transferring the precipitate CaCO₃ into the inlet of the kiln.

16. A plant as claimed in claim 14, wherein the means for catalysing the hydration of the CO₂ comprises a bioreactor comprising:

a gas inlet for receiving at least a portion of the exhaust gas from the kiln;

a liquid inlet for receiving an aqueous liquid,

a reaction chamber in fluid communication with the gas inlet and the liquid inlet, the reaction chamber containing therein immobilized enzymes capable of catalysing the hydration of dissolved CO₂ into bicarbonate ions and hydrogen ions; and

a liquid outlet in fluid communication with the reaction chamber for discharging a solution of bicarbonate ions and hydrogen ions.

17. A plant as claimed in claim 14, wherein the means for reacting the bicarbonate ions with metal ions is a reaction tank.

18. A plant as claimed in claim 14, comprising;

cleansing means for cleansing the exhaust gas;

means for transferring the exhaust gas from the kiln to the cleansing means; and

means for transferring the clean exhaust gas from the cleansing means to the catalysing means.