Method and Device for Reprocessing CO2 Containing Exhaust Gases

• US 20110094159A1
• Filed: 12/18/2008
• Published: 04/28/2011
• Est. Priority Date: 12/20/2007
• Status: Active Grant

• Current Assignee: Ecoloop GmbH
• Original Assignee: Ecoloop GmbH
• Inventors: Möller, Roland
• Granted Patent: US 8,911,520 B2
• Time in Patent Office: Days
• US Class Current: 48/113
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: C01B 2203/0283 containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 3/16 using catalysts
• CPC Class Codes: C10B 49/06 according to the moving bed type
• CPC Class Codes: C10J 2300/092 Wood, cellulose
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/0946 Waste, e.g. MSW, tires, glass, tar sand, peat, paper, lignite, oil shale
• CPC Class Codes: C10J 2300/0959 Oxygen
• CPC Class Codes: C10J 2300/0969 Carbon dioxide
• CPC Class Codes: C10J 2300/0996 Calcium-containing inorganic materials, e.g. lime
• CPC Class Codes: C10J 2300/16 Integration of gasification processes with another plant or parts within the plant
• CPC Class Codes: C10J 2300/1807 Recycle loops, e.g. gas, solids, heating medium, water
• CPC Class Codes: C10J 3/14 using gaseous heat-carriers
• CPC Class Codes: C10J 3/66 by introducing them into the gasification zone
• 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: Y02E 20/18 Integrated gasification combined cycle [IGCC], e.g. combined with carbon capture and storage [CCS]
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

The invention relates to a method for reprocessing CO₂-containing exhaust gases in a multistage reduction process. The CO₂-containing exhaust gas is conducted in the counter stream to a solid mass stream of inert bulk material and organic material that can be thermally decomposed through a plurality of zones (4, 3, 2, 1) into a pressure equalization region and is thereby converted into pyrolysis gases. In the flow direction of the solid mass stream in a fuel gas production stage (1) at 250-700° C., the organic matter is thermally decomposed under reducing conditions into short-chained hydrocarbons, hydrogen and carbon monoxide to produce coke and residue. In an intermediate stage (2) with increasing temperature, oxidation of the pyrolysis coke is carried out, wherein the developing carbon monoxide is suctioned off counter to the solid mass stream in the direction of the fuel gas production stage (1). In a carbon monoxide production stage (3) at 800-1,600° C., the remaining coke residue is converted with carbon dioxide into carbon monoxide by setting the pressure and temperature according to the Boudouard equilibrium. In a cooling stage (4), the developing solid residual material and the bulk material are cooled in the CO₂ counter stream to below 100° C. and are separated, wherein the bulk material is returned to the cycle.

Claims

1. A method for reprocessing CO₂-containing exhaust gases in a multi-stage reduction process, characterized in that the CO₂-containing waste gas is conducted in a solid mass flow of bulk material, which cannot be gasified, and a thermally decomposable organic mass, through a plurality of zones as far as a pressure compensation area and in the process is converted to pyrolysis gases, wherein, in the flow direction of the solid mass flow,

a. the organic mass is thermally decomposed under reducing conditions to form short-chain hydrocarbons, hydrogen and carbon monoxide, along with the creation of coke and a residue,

b. oxidation of the coke is performed in an intermediate state at an increasing temperature, in which the carbon monoxide being created is drawn off opposite the direction of the solid mass flow in the direction of the combustion gas generating stage,

c. remaining coke residue is converted, together with carbon dioxide, in a carbon monoxide generating stage at 800 to 1,600°

C. to carbon monoxide while adjusting the pressure and temperature in accordance with the Boudouard equilibrium,

d. solid residue materials and coarse pieces of bulk material are cooled in a cooling stage in the CO₂ counterflow to below 100°

C. and are moved out,

e. at least the removed bulk material is returned into the circulation after having been taken out.

2. The method in accordance with claim 1, characterized in that in the intermediate stage a temperature of 600 to 1,000°

C. is set and the pressure is reduced, so that in this stage a pyrolysis of the organic mass and the Boudouard equilibrium reaction run simultaneously at low pressure and low temperature.

3. The method in accordance with claim 2, characterized in that the pyrolysis gases are removed by means of an aspirating device, which creates the underpressure in the intermediate stage.

4. The method in accordance with claim 1, characterized in that a mixture of coarse and fine bulk material is employed as a pressure reservoir in a pressure compensating zone above the combustion gas generating zone.

5. The method in accordance with claim 1, characterized in that a temperature and pressure control takes place by means of the composition of the solid masses and/or their throughput speed.

6. The method in accordance with claim 1, characterized in that a temperature and pressure control takes place by means of the ratio of the supplied, thermally-decomposable organic mass, and possibly added oxygen-containing gas, to CO₂ takes place.

7. The method in accordance with claim 1, characterized in that a carbon carrier is additionally admixed to the solid mass flow.

8. The method in accordance with claim 1, characterized in that water or steam is metered into the cooling stage (4), the intermediate stage or the carbon monoxide stage.

9. The method in accordance with claim 1, characterized in that the multi-stage reduction process is performed in a calcination shaft kiln furnace, in which the bulk material is conducted from the top to the bottom, so that the carbon-containing components are thermally split with extensive oxygen exclusion and with the creation of pyrolysis gases containing short-chain molecules of a chain length of <

C₄, and the pyrolysis gases being generated are exhausted from the calcination kiln furnace.

10. The method in accordance with claim 9, characterized in that basic calcinates, their precursor stages, or inert bulk materials are employed as bulk materials, preferably in the form of quicklime (CaO).

11. The method in accordance with claim 1, characterized in that bulk material of a grain size in the range of 0.5 to 15 cm is removed from the cooling stage for return to the cycle.

12. The method in accordance with claim 11, characterized in that by means of a gas filtration the pyrolysis gases are cleaned of carried-along fine dust containing pyrolysis residue bonded to the fine bulk material particles.

13. The method in accordance with claim 1, characterized in that the pyrolysis gases are employed as synthesis gas for chemical processes and/or for thermal uses.

14. The method in accordance with claim 1, characterized in that the pyrolysis gases are separated into their gas components carbon monoxide, carbon dioxide, hydrogen and hydrocarbons by means of partial liquefaction and/or pressure change absorption.

15. The method in accordance with claim 14, characterized in that carbon monoxide is employed as the synthesis gas for use as a material in chemical processes.

16. The method in accordance with claim 14, characterized in that the separated hydrogen is employed as material for thermal and/or material purposes.

17. The method in accordance with claim 14, characterized in that the hydrocarbons are employed for thermal and/or material purposes and/or a fuels.

18. The method in accordance with claim 1, characterized in that by means of a water gas shift reaction through a catalyzed reaction below 500°

C. with water vapor, the pyrolysis gases are essentially converted into hydrogen and carbon dioxide, which are separated by means of physical separation methods, wherein hydrogen is employed for thermal and/or material uses, and the CO₂ being generated is partially returned for constituting the counterflow.

19. The method in accordance with claim 1, characterized in that the CO₂ waste gas to be reconstituted is generated in a combustion process by the use of fossil fuels, and the pyrolysis gases being created in the course of reconstitution are again employed in the combustion process.

20. The method in accordance with claim 1, characterized in that the CO₂-containing waste gas is generated in a calcination process, in which carbonates are converted into oxides by splitting them off from CO₂, in the course of which the pyrolysis gases being created during reconstitution are employed for providing a portion of the heat energy required for the calcination process.

21. A device for executing the method in accordance with claim 1, consisting of a vertical kiln furnace, to whose upper end an inlet shaft for the material mass flow, and to whose lower end a removal arrangement for solid residue materials and ash are arranged, characterized in that the inlet shaft consists of a vertical chute which, as a pressure compensation container, is filled with a mixture of gasifiable bulk material and gasifiable active materials, that an aspirating and a separation device for gas made of fine particles, are arranged in an upper section of the vertical kiln furnace, while in a central section combustion gas feed lines for controlling the oven temperature terminate in the shaft, and that gas supply devices for CO₂ and oxygen-containing gas are provided at the lower end of the kiln furnace, which are equipped with quantity governors for setting the Boudouard equilibrium in the kiln furnace, wherein furthermore a device is provided, which separates the non-gasified bulk material from the remaining solid materials downstream of the draw-off and returns it to the inlet shaft.