阅读说明：本技术 烟道气的后燃烧的方法 (Method for post-combustion of flue gases ) 是由 彼得·普利赫塔 于 2018-02-23 设计创作，主要内容包括：本发明涉及一种烟道气的后燃烧的方法,在该方法中,将硅烷或硅和氢或释放氢的化合物添加到烟道气中用于后燃烧,并且涉及一种设计用于进行该烟道气的后燃烧的方法的系统。本发明还涉及通过所述方法生产的碳化硅和/或氮化硅在建筑业中的用途以及蒸汽通过涡轮机发电的用途。(The invention relates to a method for post-combustion of flue gases, in which method silane or silicon and hydrogen or a hydrogen-releasing compound are added to the flue gases for post-combustion, and to a system designed for carrying out the method for post-combustion of the flue gases. The invention also relates to the use of the silicon carbide and/or silicon nitride produced by the method in the construction industry and the use of steam for the production of electricity by means of turbines.)

1. A method for post-combustion of flue gases,

-a silane, and/or

-feeding silicon and hydrogen or a hydrogen-releasing compound into the flue gas for post-combustion.

2. The method of claim 1, wherein the silane is selected from pentasilane, hexasilane, heptasilane, octasilane, nonasilane, decasilane, undecamsilane, dodecasilane, tridecane, tetradecane, and/or pentadecasilane.

3. The method of claim 1, wherein the hydrogen-releasing compound is ammonia.

4. The method of any of the preceding claims, wherein the silicon is present in powder or amorphous form.

5. The method of any of the preceding claims, wherein silane or silicon and hydrogen or the hydrogen-releasing compound is fed to a post-combustion device of a fossil fuel combustion system.

6. The method according to any one of the preceding claims, characterized in that silicon carbide and silicon nitride are formed by post-combustion of nitrogen, nitrogen oxides and carbon dioxide contained in the flue gas with silane or silicon and hydrogen or the hydrogen-releasing compound.

7. Use of the post-combustion products, silicon carbide and/or silicon nitride, produced using the method according to claim 6, in the construction industry, in particular in concrete construction.

8. Use of steam produced by the method of any one of claims 1 to 6 in the generation of electricity by a turbine.

9. An apparatus for carrying out a method of post-combustion of flue gas as claimed in any one of claims 1 to 6, the apparatus having a post-combustion device (8) adapted to combust flue gas.

10. The device according to claim 9, characterized in that it has a chamber (9) adapted to contain silane and/or one or more chambers adapted to contain silicon and hydrogen or a compound releasing hydrogen.

Background

It has been considered for many years that climate change is caused by the greenhouse gas carbon dioxide. Inter-government specialities relating to climate changeWith the initiative of the Gate Committee, a great deal of effort is being made to reduce CO₂To limit the global temperature rise to within at most two degrees celsius by the end of this century. They not only require reduced emissions, but also require active removal of CO from the atmosphere starting in about 2030₂. Experts believe that CO is formed₂The pressure placed in the underground chamber is critical. Chemists even aim to remove CO₂Storage in ammonia to produce nitrogen containing fertilizers holds negative belief.

Coal or natural gas is still considered necessary for power generation, since solar cells only work during daylight and good weather, and wind turbines do not rotate in the absence of wind. At the same time, to reduce CO₂It is intended to generate electricity by operating solar cells and wind turbines, which will make it possible to shut down a coal-fired power plant. Even natural gas processing power plants, which have been considered pollution-free to date, will be withdrawn from the grid.

Large quantities of carbon dioxide are produced in fossil fuel burning plants, such as gas, coal and lignite-fired power plants, cement plants, cruise ships, container ships and waste incineration plants. In most cases, flue gases produced when coal or natural gas is used to generate electricity contain very hot nitrogen, large amounts of carbon dioxide and small amounts of nitrogen oxides, but are classified as respiratory toxins and smoke particles.

Using CO₂Burning monosilanes is well known:

SiH₄+CO₂＝2H₂and (3) O + SiC. German patent application DE 4437524 a1 discusses reacting silicon-hydrogen compounds with nitrogen and/or nitrogen compounds in a combustion chamber at elevated temperature. Furthermore, german patent application DE 10145115 a1 describes the combustion of silicon-containing fuels, such as silane oil and powdered silicon, in a combustion chamber for driving an internal combustion engine.

Disclosure of Invention

It is necessary to change the way in which electricity is generated by means of natural gas or coal so that combustion gases containing heated nitrogen oxides, in particular traces of nitrogen oxides, and hot carbon dioxide are not discharged into the stack. It is therefore an object of the present invention to provide a method for removing carbon dioxide from flue gases.

This object is achieved by the features of the independent claims. Advantageous embodiments are described in the dependent claims.

The method for post-combustion of flue gases according to the invention provides:

-silanes and/or

Silicon and hydrogen or hydrogen-releasing compounds

Fed into the flue gas for post combustion.

The term "flue gas" may be understood as gaseous combustion products formed during industrial combustion of fuels, which in particular comprise nitrogen, carbon dioxide and traces of nitrogen oxides, and may comprise solid particles, such as fly ash and soot. In the present case, "post-combustion" of the flue gas is understood to be the further combustion of the flue gas resulting from the primary combustion.

In this post-combustion method using silane or silicon and hydrogen or a hydrogen-releasing compound, the energy of the hot gas is not conducted to the atmosphere via a chimney, but can be utilized by further combustion. In particular, the method according to the invention makes it possible to burn carbon dioxide in the exhaust gas by means of liquid silane. Thus, flue gas CO of an exhaust stream considered toxic may be achieved₂And NO_xPlants operated with fossil fuels are fired.

The silane may be a liquid or solid silane, particularly a liquid silane. A preferred embodiment of the present invention provides that the silane is selected from pentasilane Si₅H₁₂Hexasilane Si₆H₁₄Heptasilane Si₇H₁₆Octasilane Si₈H₁₈Nonasilane Si₉H₂₀Decasilane Si₁₀H₂₂Undecoxysilane Si₁₁H₂₄Dodecasilane Si₁₂H₂₆Tridecylsilane Si₁₃H₂₈Tetradecylsilane Si₁₄H₃₀And/or pentadecasilane Si₁₅H₃₂。

Instead of higher silanes, silicon and hydrogen or hydrogen-releasing compounds can be fed into the flue gasAnd then post-combusted. Ammonia can be used, for example, as a hydrogen-releasing compound. The silicon may be present in powder or amorphous form. For example, silicon powder and ammonia (NH)₃) May be used as a source of hydrogen. Instead of silicon powder, amorphous silicon, which is conveniently subjected to alkali etching, may be used.

A preferred embodiment provides that the silane or silicon and hydrogen or a hydrogen-releasing compound is fed into a post-combustion device of a combustion system for fossil fuels, such as coal. Prior to feeding, the flue gas may be washed to remove solid particles, such as fly ash and soot, particularly contained therein.

Assuming that the hydrogen in the silane chain attacks the oxygen atoms of the carbon dioxide and burns it to form water, the nitrogen reacts with the silicon to form silicon nitride, and the carbon bonds with the silicon to form silicon carbide. Thus, water is formed as well as silicon carbide and silicon nitride as post-combustion products. The products formed by post-combustion of nitrogen, nitrogen oxides and carbon dioxide contained in the flue gas with silanes or silicon and hydrogen or hydrogen-releasing compounds, such as silicon carbide, silicon nitride and water, can advantageously be reused.

The post-combustion may be combined with a main power generating combustion process, in particular a fossil combustion process. First, it may be advantageous to reduce CO in the exhaust stream of fossil fuel combustion based power plants₂And (5) discharging.

Another aspect of the invention provides that the steam produced by the combustion process is used, for example, to generate electricity via a turbine. In post-combustion, for example, the heat generated in the flue gas combustion chamber is much greater than the heat generated in the primary combustion of fossil fuels. Thus, post-combustion may provide additional heat of combustion. The implementation of the post-combustion method may advantageously make it possible to obtain thermal energy. Thus, at the same power output, the amount of fossil fuel can be reduced to produce the steam pressure required to operate the turbine provided in the combustion system. In particular, in combustion systems for fossil fuels, where a turbine for generating electricity is already provided, the full power output thereof can be collected and a second turbine can also be operated to increase the generation of electricity. Thus, it is reasonable to assume that ultimately the need for a primary combustion of fossil fuels, for example, combustion of only liquid silanes, can be completely eliminated.

The silicon carbide and silicon nitride compounds formed as post-combustion products constitute the required recyclable material or materials and can be collected and reused. Both materials had a diamond hardness of 9. Silicon carbide has a diamond structure, while silicon nitride is substantially resistant to heat or chemical influences.

Another aspect of the invention provides the use of silicon carbide and/or silicon nitride produced using the method according to the invention in the construction industry, in particular in concrete construction. The resulting mixture of silicon carbide and silicon nitride can therefore be used in the construction industry. The use in concrete construction is mentioned here schematically. Concrete, whether in buildings or road construction, is subject to greater loads. The load-bearing capacity of the mixed concrete can be increased by mixing silicon carbide and silicon nitride.

Another object of the invention relates to a device for carrying out the method for post-combustion of flue gases of the invention, which device has a post-combustion device or a post-combustion chamber adapted to combust flue gases. The combustion system for fossil fuels can be in particular a fossil fuel combustion plant, such as a gas-, coal-and lignite-fired power plant, a waste incineration plant, a cement plant, a cruise ship and container ship cement plants, a cruise ship and a container ship. The apparatus may be a combustion system for fossil fuels such as coal. The device may be in particular a power plant for generating electricity using coal or natural gas. A preferred embodiment provides that the silane or silicon and hydrogen or a hydrogen-releasing compound is fed to a post-combustion device, for example a post-combustion device for a combustion system of fossil fuels, such as coal. Prior to feeding, the flue gas may be washed to remove solid particles, such as fly ash and soot, particularly contained therein.

Particular embodiments of the apparatus provide that it has a chamber adapted to contain silane, such as a tank and/or one or more chambers for containing silicon and hydrogen or a hydrogen-releasing compound.

Drawings

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In the drawings:

FIG. 1 schematically illustrates a combustion system for performing post-combustion in accordance with a particular embodiment of the invention.

Fig. 2 is an enlarged view of the exhaust gas combustion chamber shown in fig. 1 to illustrate the chemical post-combustion process.

FIG. 3 schematically illustrates a combustion system for post-combustion in accordance with another particular embodiment of the invention.

Detailed Description

Fig. 1 shows a combustion system for fossil fuels, in which natural gas or coal is burned in a combustion chamber 1. In a tank or reservoir 2 located above it, steam 3 is generated by combustion and drives a turbine 5 by feeding, preferably regulated by a valve 4. The turbine 5 and the generator are used for generating electricity. The flue gas is conducted via an exhaust gas duct 6 into an exhaust gas combustion chamber 8, in particular after scrubbing of the flue gas in a suitable device 7. There, the carbon dioxide of the flue gas is combusted with the aid of silane, or silicon and hydrogen, or a hydrogen-releasing compound, for example liquid silane from the silane tank 9, to form silicon carbide and steam. The nitrogen and trace nitrogen oxides of the flue gas are combusted there to form silicon nitride and steam. The energy generated there should likewise be used to promote the production of steam. The residual gases can be removed from the waste gas combustion chamber 8 via the residual gas discharge 10, while SiC and Si can be removed₃N₄In this way it collects as a powdery mixture in the bottom, facilitating its removal from the exhaust gas combustion chamber via the removal zone 11.

To illustrate the post-combustion process, fig. 2 schematically shows an enlarged view of the exhaust gas combustion chamber 8 of fig. 1, in which hydrogen (H) of the silane chain attacks carbon dioxide (CO)₂) And burning them to produce water (H)₂O). Reaction of nitrogen (N) with silicon (Si) to form silicon nitride (Si)₃N₄). At this time, carbon (C) is combined with silicon (Si) to form silicon carbide (SiC).

FIG. 3 illustrates another particular embodiment of a combustion system for performing post combustion. In this particular embodiment of the combustion system, the combustion chamber 1 for fossil fuels and the waste gas combustion chamber 8 are located next to each other, wherein natural gas or flue gas is combusted in this combustion chamber 1The coal, in the exhaust gas combustion chamber 8, further burns the flue gas produced there. Above the combustion chamber 1, where natural gas or coal is burned, the system features a tank or water reservoir 2, where steam 3 is generated, which steam 3 drives a turbine 5, preferably via a feed regulated by a valve 4. In this particular embodiment of the combustion system, flue gases from the combustion of fossil fuels are led via a feed 12 into a flue gas combustion chamber 8, in which flue gas combustion chamber 8 carbon dioxide, nitrogen and nitrogen oxides in the flue gases are combusted by means of silane, which is fed from a silane tank 9 to form silicon carbide and silicon nitride. The residual gases can be removed from the waste gas combustion chamber 8 via the residual gas discharge 10, while SiC and Si can be removed₃N₄Can be removed via the removal region 11.

This particular embodiment of the combustion system can be realized in a new configuration of the combustion system, wherein the combustion chamber 1 for fossil fuel and the waste gas combustion chamber 8 are located next to each other. The dense structure of the combustion chamber facilitates the feeding of flue gas. In particular, the use of the heat of combustion from the combustion of silane to generate steam is also simplified; separately, it is made possible to utilize this energy in the tank 2, wherein the water is heated jointly by combustion of fossil fuels and silane.

List of reference numerals

1 combustion chamber

2 Water storage device

3 steam

4 valve

5 turbine

6 waste gas pipe

7 apparatus for scrubbing flue gases

8 waste gas combustion chamber

9 silane tank

10 residual gas discharge port

11 SiC and Si₃N₄Removed region of

12 exhaust gas feed