METHOD FOR GENERATING THERMAL ENERGY AND CHEMICAL FEEDSTOCK BY MEANS OF ALUMINO-THERMAL REACTION

Abstract

A process for generating thermal energy and basic chemicals having the following steps: a) producing aluminum metal by fused-salt electrolysis in a fused-salt electrolysis plant, b) using aluminum metal for the generation of thermal energy and of chemical basic materials selected from the group carbon monoxide or hydrogen, by bringing carbon dioxide and/or water or a mixture containing a compound containing nitrogen and hydrogen and carbon dioxide and/or water into contact with the aluminum metal and converting it in an aluminothermic reaction to aluminum oxide and carbon monoxide and/or hydrogen, c) storage or chemical conversion of the carbon monoxide and/or hydrogen produced thereby, d) storage of the thermal energy generated in the process or conversion into other forms of energy, and e) recycling the aluminum oxide obtained in the process to the fused-salt electrolysis.

The process allows fused-salt electrolysis plants for aluminum production to be operated with regenerative energies of fluctuating output over time without having to shut down these plants. The process also allows energy generation to be coupled with the provision of basic chemicals that can be used in a closed-loop process.

Claims

1.-19. (canceled)

20. A process for generating thermal energy and basic chemicals comprising at least the steps: a) producing aluminum metal by fused-salt electrolysis in a fused-salt electrolysis plant, b) using aluminum metal for the generation of thermal energy and of chemical basic materials selected from the group carbon monoxide or hydrogen, by bringing carbon dioxide and/or water or a mixture containing a compound containing nitrogen and hydrogen and carbon dioxide and/or water into contact with the aluminum metal and converting it in an aluminothermic reaction to aluminum oxide and carbon monoxide and/or hydrogen, c) storage or chemical conversion of the carbon monoxide and/or hydrogen produced thereby, d) storage of the thermal energy generated in the process or conversion into other forms of energy, and e) recycling the aluminum oxide obtained in the process to the fused-salt electrolysis.

21. The process according to claim 20, wherein in step b) carbon dioxide and/or water is brought into contact with the aluminum metal.

22. The process according to claim 20, wherein the aluminum metal used in step b) has been partially produced in the fused-salt electrolysis system in which step a) was carried out.

23. The process according to claim 20, wherein at least part of the thermal energy released by the aluminothermic reaction is used to generate electrical energy.

24. The process according to claim 20, wherein at least part of the thermal energy released by the aluminothermic reaction is used to heat the electrolyte and/or the aluminum in the fused-salt electrolysis plant.

25. The process according to claim 20, wherein the fused-salt electrolysis plant is operated using intermittently fluctuating or intermittently absent electrical energy from an external source, and wherein at least part of the thermal energy released by the aluminothermic reaction is used to keep the electrolyte and/or the aluminum liquid in the fused-salt electrolysis plant.

26. The process according to claim 22, wherein the fused-salt electrolysis plant is operated using intermittently fluctuating or intermittently absent electrical energy from an external source, and wherein at least part of the electrical energy generated is used to reduce or compensate for the fluctuation or absence of electrical energy supplied from external sources.

27. The process according to claim 20, wherein in step b) both carbon monoxide and hydrogen are produced, which are subsequently chemically reacted with one another in a Fischer-Tropsch reaction.

28. The process according to claim 20, wherein the aluminothermic reaction is carried out by bringing carbon dioxide and/or water vapor or a gaseous mixture comprising a compound containing nitrogen and hydrogen and carbon dioxide and/or water vapor into contact with liquid aluminum metal.

29. The process according to claim 28, wherein the aluminothermic reaction is carried out by bringing carbon dioxide and/or water vapor into contact with liquid aluminum metal.

30. The process according to claim 28, characterized in that the aluminothermic reaction is carried out by bringing a gaseous mixture containing ammonia and carbon dioxide and/or water vapor into contact with liquid aluminum metal.

31. The process according to claim 28, wherein gaseous carbon dioxide and liquid aluminum metal are brought into contact with each other until a gaseous reaction product with a carbon monoxide content of at least 30% by volume is formed, or wherein water vapor and liquid aluminum metal are brought into contact with each other until, until a gaseous reaction product with a hydrogen content of at least 30% by volume is formed, or wherein a gaseous mixture containing ammonia and water vapor and/or carbon dioxide and liquid aluminum metal are brought into contact with one another until a gaseous reaction product with a hydrogen content of at least 30% by volume is formed.

32. The process according to claim 31, wherein liquid aluminum is brought into contact at a temperature >660° C. with metered gaseous carbon dioxide or water vapor or with metered gaseous mixture of ammonia and carbon dioxide and/or water vapor to obtain a reactant mixture with a CO content or with an H.sub.2 content of more than 30 vol. % by controlling partial pressures and residence time at the aluminum contact by contact length and/or contact duration.

33. The process according to claim 31, wherein liquid aluminum is brought into contact at a temperature >660° C. with metered gaseous carbon dioxide or water vapor or with metered gaseous mixture of ammonia and carbon dioxide and/or water vapor to obtain a reactant mixture with a CO content or with an H.sub.2 content of more than 66 vol. % by controlling partial pressures and residence time at the aluminum contact by contact length and/or contact duration.

34. The process according to claim 20, wherein the aluminothermic reaction takes place in the absence of oxygen gas.

35. The process according to claim 20, wherein the carbon dioxide used originates from combustion processes or is obtained from the atmosphere or seawater.

36. A process for generating thermal energy and carbon monoxide by alumino-thermic reaction of carbon dioxide, in which aluminum metal and carbon dioxide are reacted and converted to aluminum oxide and carbon monoxide, wherein gaseous carbon dioxide and liquid aluminum metal are brought into contact with one another until a gaseous reaction product containing carbon monoxide, preferably with a carbon monoxide content of at least 30% by volume, is formed.

37. A process for the production of thermal energy and hydrogen by aluminothermic reaction of water vapor or of a gaseous mixture containing a compound containing nitrogen and hydrogen and carbon dioxide and/or water vapor, in which aluminum metal and water vapor or a gaseous mixture containing a compound containing nitrogen and hydrogen and carbon dioxide and/or water vapor are reacted and converted to aluminum oxide and hydrogen, wherein water vapor or the gaseous mixture containing a compound containing nitrogen and hydrogen and carbon dioxide and/or water vapor and liquid aluminum metal are brought into contact with one another until a gaseous and hydrogen-containing reaction product.

38. The process according to claim 37, wherein the compound containing nitrogen and hydrogen is ammonia and the hydrogen-containing reaction product formed is at least 30 percent by volume.

39. A process for the production of thermal energy and carbon monoxide and/or hydrogen by aluminothermic reaction of carbon dioxide and/or of water and/or of a mixture containing a compound containing nitrogen and hydrogen and carbon dioxide and/or water which comprises utilizing a liquid aluminum metal.

Description

EXAMPLE

Aluminothermic Reduction of Carbon Dioxide on Liquid Aluminum

[0105] Within the framework of a feasibility study, the reductive behavior of liquid aluminum towards carbon dioxide and the reaction products formed in the process are to be investigated. A condition for carrying out the aluminothermic reaction should be that it takes place in a closed apparatus in a carbon dioxide stream. The gases released during the reduction of the carbon dioxide were collected in a PTFE gas bag and were analyzed by gas chromatography.

[0106] The experimental or reaction apparatus consisted of a quartz tube with ceramic furnace. Liquid aluminum was oxidized with pure carbon dioxide (CO.sub.2, GA 370) in a specially made quartz tube (dimensions: approx. 60 cm length 8 cm diameter) under controlled heating in a ceramic furnace. For this purpose, mg quantities of aluminum were liquefied in the quartz tube. After purging with nitrogen, carbon dioxide was passed over the molten aluminum at a flow rate of about 100 ml/minute. In a strong exothermic reaction, spontaneous ignition of the aluminum occurred, which lasted for about 15 seconds and did not extinguish until the aluminum was apparently converted.

[0107] During the self-ignition phase, an aliquot of the escaping gas stream was collected in a PTFE gas bag (Grace PTFE sampling bag, Art. 8605719) and the qualitative and quantitative composition of the reaction gas mixture was subsequently analyzed by gas chromatography. In comparison, an aliquot of the gas stream was taken as a blank before heating the aluminum and the composition was also analyzed by gas chromatography (GC).

[0108] GC measurement parameters

[0109] Stationary phase : Molecular sieve 5 Å

[0110] Carrier gas: Helium 4.6, Messer Griesheim

[0111] Carrier gas control: flow controlled

[0112] Column flow [ml/min]: 20

[0113] Injector temperature [° C.]: 150

[0114] Detector type: WLD

[0115] Detector temperature [° C.]: 150

[0116] Oven temperature [° C.]: 80

[0117] Injection volume [μL]: 250

[0118] Result

[0119] In the collected gas mixture >33% carbon monoxide was determined.

[0120] Even with undercoating at the analytical frit, CO partial pressure was immediately indicated by the instrument.