WO2009053112A2 - Method for providing energy using a mixture, and corresponding system - Google Patents

Abstract

The invention relates to a system (100) for the controlled conversion of mixtures (12) containing carbon, wherein heat is released and the gaseous and solid reaction products are entrapped and reused. The system (100) comprises a respective gas control (S) in order to be able to control the gases used in the reactions as necessary.

Description

 Method for providing energy using a mixture and corresponding installation

This application claims the benefit of International Application PCT / EP2007 / 061574 entitled "SAND, SLATE AND OTHER SILICON DIOXIDE SOLVENT COMPOUNDS AS AN INITIATIVE SUBSTANCE FOR PROVISION OF SILICON FUEL COMPOUNDS AND CORRESPONDING METHODS OF OPERATING POWER PLANTS", filed Oct. 26, 2007.

It is currently being researched and developed in various directions in order to find a way to reduce anthropogenic CO ₂ emissions and also the emission of nitrogen oxides. Particularly in the context of energy production, which is often done by the burning of fossil fuels, such as coal or gas, there is a great need for CO ₂ and nitric oxide reduction. Hundreds of millions of tons of CO ₂ and nitrogen oxides are released into the atmosphere through such processes every year.

The object of the present invention is to name possible fossil raw materials and to describe their technical implementation. The process Chemical considerations for use are characterized in that the substances present in the raw materials and other mixtures participate in a reaction (in a power plant process). These reactions are similar to physiological processes that occur, for example, in the human body.

According to the invention, a stripping, decomposition mixture or an artificial mixture is used as a raw material which, in addition to hydrocarbons, also comprises silicon compounds. Particularly advantageous is the use of lignite with sand and / or silicates (for example in the form of diatomaceous earth casings), which mixture need not be separated before it is subjected to a multi-stage combustion process according to the invention. Particularly suitable is the so-called diatom carbon.

Diatom carbon includes a brown coal fraction and kieselguhr. The diatomaceous charcoal has a very low calorific value (about 50 percent compared to the reference coal) and an extremely high proportion of ash. The ash content largely comprises kieselguhr. Therefore, it was previously considered technically meaningless to burn this coal in a power plant process to produce heat or electricity.

However, an artificial mixture may also be used as a raw material comprising wood components and a siliceous material (e.g., sand or shale). Highly compacted, easily transportable forms of this artificial mixture (for example in the form of pellets or briquettes) have proven particularly useful.

Further details and advantages of the invention will be described below with reference to exemplary embodiments.

In the drawings, various aspects of the invention are shown schematically, wherein the drawings show: Fig. 1: a schematic of a first exemplary inventive

embodiment; 2 shows a scheme of a second exemplary inventive

embodiment; 3 is a schematic of a third exemplary invention

embodiment; 4 is a schematic of a fourth exemplary invention

Embodiment.

Detailed description

The invention will now be described by way of example. A first example relates to the application of the invention in a power plant operation to burn and / or react therefrom the stripping mixture (hereinafter referred to as mixture) in an intelligent and selectively controlled manner with suitable gases. Preferably, first with oxygen and then with nitrogen "burned", respectively brought to reaction.

This novel power plant approach uses all the essential components or constituents of the mixture and controls the necessary gases in a controlled manner so that the desired processes and reactions take place in the prescribed manner. In addition, not only the implementation of the components of the mixture is individually optimized by the multi-stage design, but it can also the resulting exhaust gases and products are controlled.

According to the invention, for example, the CO ₂ exhaust that has previously been produced during fossil combustion is reduced or eliminated. Nitrogen oxides can no longer or only in small quantities arise. According to the invention, there are a number of targeted chemical reactions or processes in which arise from the starting materials (also called reactants or reactants) new chemical compounds (called products). The reactions according to the invention are designed in such a way that preferably an oxygen-based combustion and a nitrogen-based "combustion" of the mixture or of the constituents of the mixture takes place, resulting in CO ₂ -GaS being converted (chemically) to a sodium carbonate solid (eg soda) For example, nitrogen can be bound in the form of silicon nitride.

As a starting material is used in a first embodiment, for example, diatomaceous charcoal. Separation of the constituents of the diatom carbon is not necessary because, as will be explained below with reference to FIG. 1, the entire mixture is reacted step by step.

The mixture is fed to a reaction chamber, for example in the form of a burner or a combustion chamber (first combustion region 10). In this first combustion region 10, the carbon content of the mixture 12 is burnt with the supply of oxygen-containing gas O (preferably with an oxygen concentration that is more than 50%). Particularly advantageous is an oxygen-containing gas having an oxygen concentration of more than 95%. In Fig. 1 is schematically indicated that the oxygen-containing gas O passes through a pipe 14 (eg, a lance) in the first combustion region 10. It is obvious that there are various possibilities for introducing the oxygen-containing gas O. By burning the carbon content of the mixture 12, an enormous amount of heat is released, which can be used in part for the subsequent process step, as indicated in Fig. 1 by the arrow Wl. A large part of the amount of heat generated can be used for example by means of a heat exchanger 13 for providing steam. With the steam, for example, a turbine can be driven to generate electricity. During the combustion of the carbon content of the mixture 12 in oxygen-containing gas O, flue gas is produced which contains almost only CO ₂ . By a trigger 11, this flue gas can be collected.

Since combustion takes place in a strongly oxygen-containing atmosphere in this first step, the process according to the invention can e.g. used in the environment of an oxyfuel plant.

The remainder of the mixture 22 is then heated strongly, preferably to temperatures above 1500 ^° C. The heating is preferably carried out by supplying gaseous hydrocarbons (eg methane, butane or propane), preferably propane gas (analogous to propane nitration), or other gaseous Kohlungsmitteln to separate the silicon compound of the mixture. The gaseous hydrocarbons (also referred to herein as gasl) are preferably supplied through a pipe 24 (eg a lance).

This step may be performed in the first firing range 10, but in a preferred embodiment, the mixture 12 is conveyed from the first firing range 10 into a second firing range 20 (e.g., by a screw conveyor). The silicon compound of the remaining remainder of the mixture 22 is then heated and separated in this second combustion region 20. Silicon (preferably in the form of silicon radicals) is produced here from the silicates (diatomaceous earth) of the diatom carbon.

Nitrogen gas N is now supplied in the second combustion region 20 in order to convert silicon from the silicon compound with nitrogen from nitrogen gas into silicon nitride. This reaction is exothermic, i. it releases (heat) energy. The nitrogen gas N is preferably supplied through a pipe 25 (e.g., a lance). Preferably, the nitrogen gas has a nitrogen concentration above 50%, preferably above 80%).

In a preferred embodiment, the mixture 22 is conveyed from the second combustion region 20 into a third region (called reaction region) (For example, by a screw conveyor), there to perform the exothermic conversion to silicon nitride.

In the embodiment shown in FIG. 1, however, this conversion takes place in the second combustion region 20. This combustion region 20 is therefore equipped in the case shown with means 24, 25, 26 for the individual supply of at least two different gases and different amounts of these gases enable.

The flue gas produced in the second and / or third combustion region 20 can be collected via a trigger 21. By burning the mixture 22, an enormous amount of heat is released, which can be used in part for the subsequent process step, as indicated in Fig. 1 with reference to the arrow W2. A large part of the heat generated can be used for example by means of a heat exchanger 23 for providing steam. With the steam, e.g. a turbine to be powered to generate electricity.

Below or in the region of the second and / or third combustion region 20, a reservoir 30 may be provided to receive the resulting silicon nitride. The silicon nitride may be removed, for example, as indicated by the freight car 31.

The carbon dioxide-containing flue gas resulting from combustion of the carbon fraction of the mixture 12 in the strongly oxygen-containing atmosphere can, according to the invention, be introduced into an ammonia salt solution in order to convert the carbon dioxide content of the flue gas into soda or another sodium carbonate compound. A corresponding method for reaction in soda or in another sodium carbonate compounds is the subject of the patent application EP 07 104 246.9 filed on 15.3.2007 at the European Patent Office. In a further embodiment, CO ₂ can be blown into the second or third combustion zone 20 as a gaseous reactant. This CO ₂ can be, for example, the CO ₂ off-gas, which is obtained in large quantities in the combustion in the first combustion zone 10 and so far escapes into the atmosphere in many cases. The silicon in the combustion chamber reacts in this case with the CO ₂ to silicon carbide (SiC). This reaction is slightly exothermic.

In addition, the second or third combustion zone 20 may be temporarily supplied with oxygen-containing gas. Instead of the oxygen-containing gas, or in addition to this gas, steam or hypercritical H ₂ O at over 407 ° C can be supplied to the process. But it can also be carbon dioxide (eg from the exhaust gas) are supplied to compensate for example, a lack of carbon in the mixture 12 or 22. This additional gas (oxygen or steam or carbon dioxide) is indicated in Fig. 1 with Gas2.

As a starting material is used in a second embodiment, for example, a mixture of brown coal together with overburden, which includes silicon compounds (sand, shale, etc.) contains. A separation of the components of the mixture is not necessary because, as will be explained below with reference to FIG. 2, the entire mixture is reacted step by step.

In contrast to the installation shown in FIG. 1, only one reactor or combustion area 10/20 is used in the installation according to FIG. 2. The entire reaction process takes place in this firing range 10/20. A plurality of gas supply means 14, 24, 25 (e.g., gas lances) are provided to bring at the given times the gases necessary for the individual reactions in the firing range 10/20. The course of the reactions is otherwise identical to the procedure described in connection with FIG.

Another possible embodiment is indicated schematically in FIG. Here is a horizontally mounted, tubular reactor 33 is used. The reactor 33 either rotates about its longitudinal axis and has a helical structure on the inside. Due to the rotational movement, the helical structure promotes the mixture from left to right. However, the reactor 33 may also have a screw which sits in the interior and which is driven to convey the mixture from left to right.

On the left side, the mixture 12 is shown, which was introduced into the reactor 33. Above the mixture is shown tube 14 (eg, a lance), which has multiple outlet openings and which allows the mixture 12 to be burned quickly and efficiently in a high oxygen-containing atmosphere. In addition, coils 32 may be disposed in an induction zone about the entrance area, respectively, in the first combustion zone 10 of the reactor 33 to accelerate the heating and reacting of the mixture 12, or to dry the mixture 12 before it is burned. The fact that the carbon content of the mixture 12 is burned reduces the volume of the mixture 12. At the same time, the remaining portion 22 of the mixture is conveyed to the right into the second combustion zone 20. In this combustion zone 20, as required, different amounts of gases through the tubes 24 and 25 (eg, gas lances) supplied to control the implementation of the remaining portions 22 of the mixture. Part of the resulting material (eg elemental silicon Si ₂ ) can be in liquid form in a container

34, which sits below the second combustion zone 20. The remaining share

35 of the mixture can be further promoted to the right within the reactor 33 and removed from there to the reactor 33. As with the other systems 100, a heat exchanger 23 may be provided. To suppress undesirable reactions and to stop uncontrollable processes, an emergency flood system 36 may be provided at reactor 33 for flooding the interior of the reactor with inert gas (e.g., argon).

Particularly suitable is a rotary kiln with internally encircling screw channel, or a static furnace with sintered Si ₃ N ₄ screw conveyor, which withstands the high temperatures. A presently preferred embodiment of the invention is shown in FIG. It is a plant 100, which has been specially optimized for the present process and allows a particularly good flow of the mixture 12 and a good supply of reaction gases and discharge of the exhaust gases. The reactor 40 has a rotationally symmetrical structure. The axis of symmetry A extends centrally through the reactor 40. The reactor 40 is characterized in that it has a first outer conical or inclined surface 42 inclined obliquely inwards. This surface 42 merges into a second inclined surface 43, which is steeper and is also inclined inwards. On the outer periphery of the reactor 40 doors or flaps 44 are provided, which allow filling of the reactor 40 with the mixture 12 from the outside. Preferably, tracks or roads are laid out around the reactor 40 to deliver the mixture 12 by cars or trucks. When the doors or flaps 44 are opened, the mixture 12 can be introduced. Gravity allows newly introduced mixture 12 to slowly slide down the inclined surface 42. Below this inclined surface heating means 45 may be arranged to dry and / or preheat the mixture 12. More toward the center of the reactor 40 towards a first gas distribution head 46 is provided, which is supplied from below via a tube 14 with strongly oxygen-containing gas O. In the first combustion zone 10, the mixture 12 is swirled by the injection of the oxygen-containing gas O, as indicated by the cloud 41. The swirling mixture 41 is burned with the oxygen gas O and the carbon fraction rises as CO ₂ -GaS upward and is captured there by the trigger 11. The turbulence causes a drastic increase in the surface area of the mixture 12 and the combustion process is more efficient and complete. If the temperatures are not sufficient, which occur in the range 10, then by a second Gasverteil köpf 47, which is designed here as a conical head, from the center of hydrocarbon gas (eg propane, butane or methane), here referred to as Gasl blown become. By suitable control of the processes by means of a controller S, the temperature can be adjusted so that the silicon compounds of the remaining part 22 of the mixture are split become. The hydrocarbon gas Gasl may be supplied through a pipe 24.

If now a conversion to silicon carbide is desired, then further hydrocarbon gas is injected, wherein a portion of the carbon of the hydrocarbon gas then reacts with elemental silicon to SiC and deposited in the bottom region of the combustion zone 20.

Now, if a conversion to silicon nitride is desired, then nitrogen gas N is blown in, wherein a portion of the nitrogen then reacts with elemental silicon to Si ₃ N ₄ and deposited in the bottom region of the combustion zone 20. The nitrogen gas N can either be injected through the second gas distribution head 47 or, as indicated in FIG. 4, it can be blown through a third gas distributor 48. The nitrogen gas N may be supplied through a pipe (s) 25.

In the lowermost region of the reactor 40, in turn, doors or flaps 49 may be arranged to remove the (Rekations-) product (eg SiC or Si ₃ N ₄ ) by opening these doors or flaps 49. After opening the doors or flaps 49, the (Rekations-) product, for example, impinge on a cone 52 with sloping outer surfaces to slip outwards.

Above the second combustion zone 20, a trigger 21 is provided, which receives gases that have not reacted.

Regardless of the specific embodiment, the invention is characterized in that several reactions go hand in hand. The individual reactions are controlled according to the invention by controlling the amounts of the mixture 12 and by controlling the gas pressures and gas flows. Preferably, numerous pressure, temperature and gas sensors are provided inside and / or at the plant 100. These sensors provide control variables for a control S of the plant. In the control (with the control S) of the running in the system 100 complex processes that need to be optimized for the substance, the gas flows, respectively gas quantities, the temperature-time regime and the amount of the mixture to be reacted 12, respectively, the composition taken into account.

In Fig. 4, this control S is indicated schematically. An analog controller S can also be used in the other systems 100. In order to clarify the principle of operation of the invention, the gas sources 50 in the form of gas cylinders are schematically illustrated. It is obvious that 100 other gas sources 50 are used in a large-scale plant. The gas pressures and gas flows of the individual gases are controlled as required by means of controlled gas supplies 51.

With suitable control software (which may be part of the controller S, for example), all processes can be conducted in such a way that the fullest possible conversion takes place in the desired direction.

An additional gas (Gas2) can be used, as described above. For this reason, a corresponding gas source is shown in FIG. As additional gas but also carbon dioxide from the trigger 11 can be fed to the process again.

In the nitrogen coupling to silicon (which takes place in the second combustion zone 20 or in a third combustion zone), preferably the pure nitrogen atmosphere from the ambient air is achieved by combustion of the oxygen content of the air with propane gas (known from propane nitration).

However, the nitrogen gas and the oxygen gases can also be provided by means of the Linde method.

Like silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ) is more wear resistant Material that can or will be used in highly stressed parts in mechanical engineering, turbine construction, chemical apparatus, engine construction.

Further details on the described chemical processes and energy processes can be found on the following pages.

Silicon burns with nitrogen to silicon nitride at 1350 ^° C. The reaction is exothermic

T = 1350 ⁰ C 3 Si + 2 N ₂ (g) -> Si ₃ N ₄ Δ H = - 744 kJ / mole (exothermic)

Silicon reacts with carbon slightly exothermic to silicon carbide.

Si + C ^ SiC Δ H = - 65.3 kJ / mol (exothermic)

On the other hand, silicon carbide can be obtained endothermically directly from silicon dioxide and carbon at around 2000 ^° C.

T = 2000 ⁰ C

SiO ₂ + 3 C (g) -> SiC + 2 CO Δ H = + 625.3 kJ / mol

(Endothermic)

To aid in the conversion of the silicon compounds of the mixture (diatomaceous earth) to silicon and the conversion ("combustion") to silicon carbide or silicon nitride, a thermite reaction may be occasionally initiated by, for example, aluminum and ferric oxide is introduced.

It has already been mentioned that the CO ₂ can be converted into soda (sodium carbonate). The resulting in this reaction ammonium chloride (NH ₄ CI) can be converted into ammonia (NH ₃ ) and silicon tetrachloride (SiCl ₄ ). The silicon tetrachloride (SiCI ₄ ) in turn can be used in the production of silanes according to a P. Plichta described methods are used.

The silicon nitride can be reacted in ammonia, with the ammonia used to produce the ammonia salt solution for soda production. The conversion to ammonia may be by hydrolysis or by the addition of a caustic (e.g., KOH).

The ammonia can be used to serve as salt heat storage.

Upon conversion to soda, ammonium chloride is formed using the ammonium chloride to produce salt for a salt heat store. However, it is also possible to produce an ammonium salt which is able to safely and effectively store ammonia.

The production of silicon carbide and silicon nitride may also be combined as follows. Here, (elemental) silicon, which is produced in a reduction process (eg in the third combustion zone), is used. A portion of the silicon may be used to bind carbon dioxide resulting, for example, from heating the silica solids. This bonding process produces silicon carbide and CO ₂ silicon carbide in a slightly exothermic process. The rest of the silicon can be reacted with nitrogen gas as a reactant to silicon nitride. This process is highly exothermic.

Part of the heat energy generated in these exothermic processes can be used to prepare the reductant.

In a further embodiment of the invention, an artificial mixture is used as a raw material comprising wood components and a siliceous material (eg sand or shale). Especially have proven highly compressed, easy to transport forms of this artificial mixture (eg in the form of pellets or briquettes). The pellets or briquettes can be pressed from dry, natural residual wood (sawdust and wood shavings) together with eg sand into the desired shape. They are pressed under high pressure and have an extremely low water content and a high inherent density. Therefore, there is only a small storage and transport volume. Preferably, the wood-containing lignin is used as a binder for the pellets or briquettes to combine both the wood, carbon, and silicon compounds. Also possible is the use of wood shares, which are sheathed or surrounded by a silicon compound.

In a particularly preferred embodiment of the invention, this mixture is foamed before or during the combustion or inflated by heat and containing gas components (popcorning), so as to significantly increase the surface area and promote the chemical reactions.

first firing area 10

Deduction 11

Mixture 12

Heat exchanger 13

Pipe 14

second firing area 20

Discharge 21 remaining remainder of the mixture 22

Heat exchanger 23

Pipe 24

Tube 25

Pipe 26

Reservoir 30

Freight car 31

Coils 32 tubular reactor 33rd

Container 34 remaining share 35

Emergency flood installation 36

Reactor 40

Swirled mixture 41

1. oblique plane 42

2nd inclined plane 43

Doors or flaps 44

Heating means 45

1. Gas distribution head 46

2. Gas distribution 47th

3. Gas distribution head 48

Doors or flaps 49

Gas sources 50

Controlled gas supply 51

Cone 52

Annex 100

Symmetry axis A

Hydrocarbons gasl additional gas gas2

Nitrogen gas N oxygen-containing gas O

Gas control S

Amount of heat Wl

Amount of heat W2

Claims

claims: A method of providing energy using a carbonaceous mixture (12) containing carbon moieties and silicon compounds, e.g. Silicates, comprising, a) introducing the mixture (12) into a first firing range (10) and supplying oxygen (O); b) burning the carbon content of the mixture (12); c) heating the remaining mixture (22), preferably by supplying hydrocarbons (Gasl) to separate the silicon compounds, d) supplying nitrogen gas (N) to convert silicon from the silicon compounds with nitrogen into silicon nitride e) capturing carbon dioxide-containing flue gas, which arises in step a) and / or b), and introducing the flue gas into an ammonia salt solution to convert the carbon dioxide content of the flue gas into soda. 2. The method according to claim 1, characterized in that it is the mixture (12) is a tailings mixture (12) comprising lignite and silicon compounds, or - an artificial mixture of wood components and sand, slate or rubble. 3. The method according to claim 1 or 2, characterized in that residues of Silicon react with carbon to silicon carbide. 4. The method of claim 1, 2 or 3, characterized in that silicon nitride is reacted in ammonia, wherein the ammonia is used to produce the ammonia solution. 5. The method of claim 1, 2, 3 or 4, characterized in that silicon nitride is reacted in ammonia, wherein the ammonia is used to serve as salt heat storage. 6. The method of claim 1, 2, 3 or 4, characterized in that in the conversion into soda ammonium chloride is formed, wherein the ammonium chloride is used to produce salt for a salt heat storage. 7. The method of claim 1, 2, 3 or 4, characterized in that in the conversion into soda ammonium chloride is formed, which in turn is converted to ammonia. 8. The method according to any one of the preceding claims, characterized in that during the conversion into soda ammonium chloride is formed, which in turn is converted to ammonia, wherein subsequently ammonia is stored in a salt heat storage. 9. The method according to any one of the preceding claims, characterized in that the overburden mixture (12) comprises diatom carbon. 10. Attachment (100) with at least two firing zones (10, 20), - supply means (44) for introducing a mixture (12), Gas supply means (14, 46, 51) for introducing an oxygen-containing gas (O) into a first (10) of the two combustion zones, Means for carrying out a combustion process in which a portion of the mixture (12) with the oxygen-containing gas (O) burns in the region of the first (10) of the two combustion zones, - Gas supply means (25, 48, 51) for introducing a nitrogen-containing gas (N) in a second (20) of the two combustion zones; Control (S) for controlling the flow rate of the oxygen-containing gas (O) and the nitrogenous gas (N), Temperature sensors for measuring the temperature in the first (10) and / or second of the two combustion zones, the temperature sensors providing information to the controller (S), - Gas sensors for measuring the gas composition in the first (10) and / or second of the two combustion zones, wherein the gas sensors provide information to the controller (S). 11. The device according to claim 10, characterized in that it is in the mixture (12) to a - Carbonaceous overburden mixture is, the lignite and silicon compounds, eg silicates, comprises, or a - an artificial mixture of wood components and sand, slate or building rubble. 12. The device according to claim 10 or 11, characterized in that the two combustion zones (10, 20) in the interior of a common reactor (40), but are spatially separated from each other. 13. The apparatus of claim 10 or 11, characterized in that the gas supply means (14, 46, 51) for introducing an oxygen-containing gas (O) comprise a Gasverteil köpf (46), which is adapted to the oxygen-containing gas (O) with large To bring in pressure. 14. The apparatus according to claim 12, characterized in that the reactor (40) is designed rotationally symmetrical, and the supply means (44) for introducing a mixture (12) on an outer circumference of the reactor (40) are arranged. 15. The apparatus according to claim 14, characterized in that the reactor (40) has at least two inclined planes (42, 43) are inclined inwards in an inclined manner.