WO2015101408A1

WO2015101408A1 - Device and method for directly converting thermal energy into electrical energy

Info

Publication number: WO2015101408A1
Application number: PCT/EP2014/003452
Authority: WO
Inventors: Ortwin Gerrit Siebelder; Addo Slijkhuis; Daan Reiling
Original assignee: Ortwin Gerrit Siebelder; Addo Slijkhuis; Daan Reiling
Priority date: 2013-12-31
Filing date: 2014-12-20
Publication date: 2015-07-09
Also published as: DE102013022190A1

Abstract

The invention relates to a device (1) according to figure 1 for directly converting thermal energy into electrical energy, comprising a device (2) for flameless catalytic oxidation of hydrocarbons, a heat pipe (3), a thermoelectric element (4), which is connected to an electrical connection (6), and a heat sink (5), wherein the region (3.3) of the heat pipe (3) that absorbs thermal energy is in thermally conductive, electrically insulating contact with the device (2), and the region (3.4) of said heat pipe that emits thermal energy is in thermally conductive, electrically insulating contact with the hot side (4.1) of the thermoelectric element (4), and wherein the cold side (4.2), which is opposite the hot side (4.1), of the thermoelectric element (4) is in thermally conductive, electrically insulating contact with the heat sink (5). The invention further relates to a method for generating electrical energy directly from thermal energy.

Description

Device and method for direct conversion of thermal energy into electrical energy

The present invention relates to a new apparatus and method for directly converting thermal energy into electrical energy.

State of the art

Methods and apparatus for direct conversion of thermal energy into electrical energy utilizing a temperature gradient (Seebeck effect) as well as suitable materials for the manufacture of such devices are known e.g. from US Pat. No. 5,610,366 A, US patent application US 2010/0229911 A1, international patent application WO 97/44993 A1, German patent application DE 101 12 383 A1 or the company publication of Hi-Z Technology Inc., "Use, Application and Testing od Hi-Z Termoelectric Modules ", authors: FA Levitt, NB Eisner and JC Bass, known.

These devices have so-called Peltier elements or thermoelectric elements (hereinafter referred to as the one or the, or the or one or a "TEE" called) on. Basically, a TEE contains two different thermoelectric materials with different Seebeck coefficients, which are electrically conductively connected to one another at a contact point or in a contact region. Due to the thermoelectric effect, an increased temperature in the contact region causes an electrical voltage (thermal voltage) between the two thermoelectric materials. When the circuit is closed then flows an electric current.

The known devices for directly converting thermal energy into electrical energy therefore generally comprise at least one TEE which is in thermal contact with a source of thermal energy (heat source) in its contact region and in thermal contact with a heat absorbing device (heat sink) with the opposite side which removes or otherwise uses the incoming thermal energy.

This "thermal energy source / TEE / heat absorbing device configuration", on the other hand, allows a variety of applications due to the large number of heat sources on the one hand and heat absorbing devices on the other hand Applications, especially as a self-sufficient, independent of an electrical distributor sources of electrical energy.

In this case come as a source of thermal energy so different devices such as heated by solar thermal photovoltaic cells or solar cells; In general, the devices in question have the configuration

"Solar Cell / Electrically Insulating, Thermally Conductive

Layer / TEE / heat absorbing device "(see US patent applications US 2011/0048488 A1 and US 2011/0048489 A1 or US patents US 7,875,795 B2, US 4,106,952 and US 3,956,017), the waste heat of engine blocks, exhausts, flue pipes, flue gas flues , Ovens or containers with materials that provide thermal energy during phase transformations (see German Patent Application DE 199 46 806 A1, International Patent Applications WO 99/36735 and WO 01/80325 A1, the US patent application US 2006/0266404 A1 or the American

US Pat. Nos. 6,232,545 B1, 6,624,349 B1, 6,527,548 B1 and 6,053,163 B1), or US Pat

Solar collectors, in particular flat-plate collectors (see the American patent application US2010 / 0300504 A1, the European patent application EP 2

239 187 A1 or the German patent application DE 10 208 009 979 A1, DE 36 19 127 A1 and DE 37 04 559 A1) into consideration.

In particular, attempts have been made to use engine exhaust gases in exhaust systems more effectively for the production of electrical energy while simultaneously cleaning the engine exhaust gases. For this purpose, US Pat. No. 5,968,456 proposes a catalytic converter which monitors the energy of the exothermic reactions of the constituents uses engine exhaust gases on a catalyst to generate electricity using TEE. The thermal energy is conducted from the monolithic catalyst to the hot side of the TEE by means of thermal fins embedded in the monolithic catalyst.

From US patent application US 2003/0223919 A1, a comparable structure for the post-purification of engine exhaust gases with simultaneous production of electrical energy is known. This design includes a catalytic converter in heat conducting contact with the hot side of TEE. The cold sides of the TEE are in heat-conducting contact with cooling channels.

German published patent application DE 10 2008 040 849 A1 describes a catalytically active layer for the oxidation of constituents of the exhaust gases from oxidation engines, preferably diesel engines. The layer comprises bimetallic or polymetallic nanoparticles, the metals being selected from the group consisting of palladium, rhodium, platinum, iron, nickel, chromium, rhenium, ruthenium, technetium, iridium, cobalt, copper, gold and silver. The nanoparticles may be fixed on one or more support materials selected from the group consisting of titanium dioxide, silica, zirconia, alumina, zinc oxide, tin oxide, strontium oxide, calcium oxide, barium oxide, magnesium oxide, antimony oxide, bismuth oxide, chromium oxide, iron oxide, manganese oxide, oxides of lanthanides , Oxides of actinides or mixed oxides of the abovementioned oxides, zeolite-type mixed oxides and / or oxides from the group of spinels, are selected. The support material may further contain compounds such as alkali metals, halides, nitrogen, phosphorus, sulfur, gallium oxide, germanium oxide, indium oxide, manganese oxide, vanadium oxide and / or tungsten oxide as dopants or promoters. The nanoparticles have an average particle size of 5 2 nm to <5 nm.

German Offenlegungsschrift DE 10 2010 031 502 A1 discloses a tubular thermoelectric generator through which a fluid flows. The generator has an inner surface defining an inner volume radially outward and an outer surface. In the inner volume is a catalytically coated element, take place at the exothermic reactions of components of the engine exhaust. This achieves a further heat input into the TEE. Furthermore, the flameless catalytic oxidation of hydrocarbons on catalysts has been used as a heat source for TEE. Thus, in the diploma thesis of Ewald Maria Sütterlin, "Catalytic Oxidation for Electricity Generation, Studies on Thermogenerator, Gas Oxidation and Injector Burners", Diplomica® Verlag GmbH, ISBN: 978-3-8366-5863-8, 2008, a catalytic butane diffusion burner as Heat source proposed for TEE. As prototypes for catalytic butane oxidation platinum-coated sintered elements based on nickel are proposed. As a catalyst support material alumina should be used. It is not described how the TEEs are spatially and functionally arranged to the diffusion burner.

Japanese Patent Application JP 2009027876 A discloses a portable TEE with an integrated catalytic gas burner. The apparatus comprises a tubular oxidation chamber having a tubular, thermally conductive wall, an outlet for exhaust gases above the oxidation chamber, an inlet device for the fuel gas below the oxidation chamber, TEE on the outside of the thermally conductive wall, and cooling fins on the cold side of the TEE. Within the oxidation space are plate-shaped catalyst filter with holes for the gas passage. The plate-shaped catalyst filters are constructed of an aluminum-iron-chromium alloy, which may still contain lanthanides. In the area of the edges of the holes are aluminum oxide layers in which palladium / platinum catalysts are incorporated.

From ^"Japanese Patent Application JP 2004064853 A portable TEA is also known, which comprises an integrated catalytic gas burner. The catalyst of the burner is located in the cavity between two parallel plates with TEA. The cavity and the catalyst are permeable to air. The fuel gas is a The air is drawn into the two open ends of the cavity and the two open ends serve as an outlet for the exhaust gases.

Japanese Patent Application JP 2012105512 A discloses a TEE which also comprises an integrated catalytic gas burner. The catalyst is prepared by preparing a paste containing nanoparticles supported on oxide nanoparticles of platinum, palladium or gold, printed in the desired pattern on the arrangement of the TEE and calcined. A method for the catalytic removal of traces of methane in the air at 220 to 400 ° C is known from the Chinese patent application CN 1718274 A. The catalyst used is cerium oxide-supported palladium or platinum. From the Chinese patent application CN 102000570 A, the catalytic oxidation of methylbenzene at 220 to 300 ° C is known. The catalyst used is a honeycomb ceramic made of Pd / Ce 0.8 Zr 0.20 ₂ .

From the Chinese patent application CN 102407129 A a catalyst for the catalytic oxidation of methane at 380 to 545 ° C is known. The catalyst has a core-shell structure with the shell of perovskite and the core of yttria-stabilized zirconia nanoparticles.

From the Taiwanese patent application TW 201221214 A a catalytic process for the removal of organic compounds from the air is known. The catalyst used is a fixed bed of ceria-supported palladium nanoparticles with a particle size of 2 to 6 nm.

From the article by M. Cargnello, JJ Delgado Jaen, JC Hernandez Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gämez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ Ce02 Subunits on Functionalized Al ₂ 0 ₃ ", in Science, Vol. 337, pages 713 to 717, 2012, a catalyst for the catalytic oxidation of methane is known, which is composed of palladium nanoparticles, which are coated by ceria nanoparticles, (= Pd @ Ce02 The catalyst particles are bound to hydrophobized alumina surfaces.

International patent application WO 2013/145920 A1 likewise discloses catalysts based on palladium, which are applied to an inorganic porous material. The cocatalyst used is cerium oxide.

From the Taiwanese patent application TW 201323081 A the production of ceria and manganese oxide supported palladium nanoparticles is known. The materials are suitable for the catalytic removal of volatile organic compounds at 50 to 250X. From the Chinese patent application CN 103143353 A, the production of palladium-ceria nanoparticles is also known. The reducing agent used in the preparation is a powder of cacumen biotae. The known devices, which include TEE and flameless catalytic burners, have the disadvantage that the temperature and the heat energy can be controlled only by the fuel supply and the composition of the fuel gases. There is therefore always the risk of overheating of the devices. These known devices for directly converting thermal energy into electrical energy also have the disadvantage that the conduction of the thermal energy from its source to the "hot" side of the TEE and its discharge from the "cold" side of the TEE to the heat absorbing device ( Heat sink) is relatively ineffective, which reduces the efficiency of the known devices.

The upper limit of the efficiency of a thermoelectric element that generates electricity, namely given by Equation I: Equation I

_ generated electrical energy _

Heat energy absorbs on the hot side

The Carnot efficiency nc is given by Equation II: Eq.

"Generated electrical energy" is understood to mean the energy that is given off to a load, ie a device in which the electrical energy is dissipated. "Z" refers to the so-called figure-of-merit, ie the ability of a material to efficiently generate thermoelectric energy. It is defined in Equation XII.

In addition, the efficiency is greatly affected by the thermal resistance between the hot TEE electrode and the heat source having the temperature THH, and the resistance between the cold TEE electrode and the heat dissipation at the temperature Tcc. At the same thermal resistance Ri, the total thermal resistance becomes indicated by the equation III, wherein RTEE = thermal resistance of the TEEs.

Equation III

Rtotal ⁼ 2Ri + RTEE! .

This reduces the heat flow through the TEE according to Equations IV and V of

Equation IV

on equation V

This reduces the temperature drop across the TEE according to equations VI and VII of

Equation VI

on

Equation VII

The most important influencing factor on the efficiency of the TEE is according to equation VIII of the Carnot efficiency. This therefore changes from equation II

Equation VIII

, _ 1

n ^c_ric 1+ (1+ T _CC / THH) (I / TEE)

-

So is for

the Carnot efficiency is reduced by 21% and for

even by 43%, at T _C c = 70 ° C, T _HH = 250 ° C.

The thermal resistance Ri is set according to equation IX from the transition or contact resistance R _M between the TEE and the thermal conductor at one end, the transition or contact resistance R 2 between the heat conductor and the heat source at the other end and the thermal resistance R _{L of} the Heat conductor himself together.

Equation IX

The simplest thermal conductors are metal conductors with a large cross section AL, so that the line resistance according to equation X remains small. In the equation X, ki_ stands for the thermal conductivity of the metallic conductor and L for its length.

Equation X

Common, inexpensive materials with high ki_ values are Cu or Al. So that the line resistance R _L remains small enough, the cross section AL should be large.

The thermal contact resistance is determined according to Equation XI of the close contact between the materials of the two sides of the contact, wherein all the influences are summarized in the thermal contact coefficient h _c , and the area A of the contact.

Equation XI

R _h = 1 / hcA. The thermal contact is generally improved, ie h _c increases, with the number of points of contact between the two contact surfaces. For this purpose, the thermal contact can be increased with high pressure by compressing the contact surfaces. Also, a reduced surface roughness, the cleaning of the contact surfaces and a surface of high quality and planarity lead to a certain improvement. Often, a thermally highly conductive paste based on polymers containing metal-containing particles is used to also fill up the remaining "heat pipe" holes in contact. The disadvantages of using pressure are numerous.

Thus, a complex mechanical structure is necessary to achieve permanently sufficient pressure. In the case of the TEE then the entire arrangement consists of relatively heavy metallic thermal contacts and the TEE itself, which is mainly composed of ceramic parts. When heating the hot side of the TEE, the mechanical stresses increase due to the different thermal expansion coefficients of the metallic and ceramic materials. This can lead to breakage of the TEE; In any case, the mechanical stresses lead to material fatigue. In addition, the thermal contact changes during heating, because the pressure changes. Applying a thermally conductive paste can only partially solve this problem.

The contact resistance R _h is also lowered by connecting the TEE and the heat conductor directly by means of a soldered or welded joint. Due to the direct metallic connection, the h _c value is very large and thus Rh is small. Rh can not be reduced by increasing the contact area because it is limited by the dimensions of the TEE. Moreover, in this structure, the problems that occur due to the different expansion coefficients are even greater. In addition, you can not dismantle the system without further notice, eg for a repair or a later recycling.

In the US patent application US 2010/0300504 A1 a flat collector is proposed, which has a solar facing front part with a solar collector, ie an absorber of solar energy, a middle part with TEE and a rear part with cooling elements. The solar collector can be made of materials as different as metal, cement, concrete, bricks, porcelain, ceramics or Plastic exist. In addition, the solar panel can still be covered with a transparent material to use the greenhouse effect. To improve the conduction of the thermal energy to and from the individual parts, they are joined under pressure by fasteners.

As is known, however, occur in such solar panels temperature differences between the front and the rear side of up to 400 ° C. However, since in the solar collectors known from US 2010/0300504 A1 materials of different coefficients of thermal expansion are to be joined under duress as it were, there is a high risk that the mechanical stresses caused by the high temperature differences and the different coefficients of thermal expansion sooner or later lead to damage which can lead solar panels, which is a major drawback.

In order to overcome the disadvantages associated with the application of pressure, US Pat. No. 6,232,545 B1 proposes a bifurcated electrical network arrangement comprising a terraced substrate, an insulating film, a metal layer of copper, and thermophotovoltaic cells comprising the copper layer are connected. In order to avoid mechanical stresses caused by different thermal expansion coefficients, materials with similar coefficients of expansion are used for the individual components of the network arrangement. For example, in the case of GaSb cells, Cu / Invar / Cu laminates or AlSiC are used as the substrate material. The disadvantage here is the limited choice of materials.

Attempts have been made to overcome these disadvantages by using heat pipes.

A heat pipe is a gas-tight component that can be used to transport thermal energy or heat very efficiently from one place to another. It can transport 100 to 1000 times higher thermal energy than a component of the same geometric dimensions made of solid copper. The heat pipe uses the physical effect that very large amounts of energy are converted when evaporating and condensing a liquid. The heat pipe is hollow inside and filled with a small amount of liquid, the "working" liquid. This is under its vapor pressure, which is well below that at low temperatures atmospheric pressure can be. The inner wall of the heat pipe can be covered with a capillary structure - comparable to a wick. This capillary structure is saturated with a liquid heat transport medium, the "working" liquid. If energy is supplied at one point of the heat pipe, the "working" liquid from the capillary structure evaporates there. The steam flows in the direction of the temperature gradient and condenses everywhere, releasing the heat of vaporization, where energy is dissipated. The condensate, the liquefied heat transfer medium, is absorbed by the capillary structure, flows back to re-evaporate. It closes a cycle, which circulates quickly and very effectively transports thermal energy.

The temperature difference between the evaporation and condensation zone in the heat pipe is very low, so that the heat conduction is almost isothermal. Depending on which temperature range is used, different "working" liquids are used, such as water in the temperature range of about 170 to 600K, ammonia in the temperature range of about 150 to 170K, mercury in the temperature range of 400 to 800K or lithium or silver in a temperature range above 1000K.

Heat pipes can be used for example in Peltierelement / Heat pipe cooling systems.

In addition, devices with TEE are known in which the heat energy is conducted by means of heat pipes to the hot side of the TEE and / or from the cold side of the TEE to a heat sink (see the German patent applications DE 33 14 166 A1 and DE 10 2008 005 334 A1, US Pat. No. 4,520,305, Japanese Patent Applications JP S5975684 A and JP S60125181 A or International Patent Applications WO 2011/024138 A2, WO 2011/120676 A2 and WO 2013/092394 A2).

Object of the present invention

The present invention was based on the object to propose a new device and a new method for the direct conversion of thermal energy into electrical energy. The new device and the new method should be the Disadvantages of the prior art no longer have, but they should allow a particularly efficient transport of thermal energy from the power source to a thermoelectric element (TEE) and the efficient dissipation of the supplied thermal energy from the TEE to a heat absorbing device. The selection of the materials used to construct the new device should be subject to less or no restrictions with regard to their thermal expansion coefficients. Nevertheless, in the new device and in the new method no or only negligible, caused by different thermal expansion coefficients thermal stresses occur. Overall, the new device and the new method should have a higher efficiency than the devices and methods of the prior art. In addition, the new device and method should significantly reduce, if not eliminate, the risk of device overheating during operation. Not least, the new devices should be compact, robust and portable and have a long service life.

The solution according to the invention

Accordingly, the new device (1) for direct production of electrical energy from thermal energy was found, comprising as heat source at least one device (2) for flameless catalytic oxidation of hydrocarbons having at least one reaction space (2.1), at least one inlet device (2.2) for a Gas or a gas mixture (2.3), at least one exhaust device (2.4) for the exhaust gases

(2.5) and a wall (2.6), as a carrier of thermal energy at least one heat pipe (3) with a connection region (3.1), a fluid-tight wall (3.2), a thermal energy receiving area (3.3) and a thermal energy emitting area (3.4 ), at least one thermoelectric element (4) with electrical connections (6) and at least one heat sink (5), wherein the at least one heat pipe (3) with its thermal energy receiving area (3.3) in heat-conducting contact with the at least one device (2) and with its thermal energy emitting area (3.4) in heat-conducting, electrically insulating contact with the hot side

(4.1) of the at least one thermoelectric element (4) and wherein the hot side (4.1) opposite, cold side (4.2) of the at least one thermoelectric element (4) in thermally conductive, electrically insulating contact with the at least one heat sink (5 ) stands.

In the following, the new device for direct conversion of thermal energy into electrical energy is referred to as "device according to the invention". In addition, the new method for the direct conversion of thermal energy into electrical energy has been found, in which the thermal energy delivered by at least one heat source (2) by means of at least one heat pipe (3) to the hot side (4.1) of at least one thermoelectric element (4) is transported by the supplied thermal energy in the at least one thermoelectric element (4) an electrical voltage is generated and the remaining supplied thermal energy from the hot side (4.1) opposite cold side (4.2) of the at least one thermoelectric element (4) a heat sink (5) is supplied, characterized in that one uses for this purpose the device according to the invention. In the following, the new method for the direct conversion of thermal energy into electrical energy is referred to as "inventive method".

Advantages of the Invention In view of the state of the art, it was surprising and unforeseeable for a person skilled in the art that the object on which the present invention was based could be achieved by means of the device and the method according to the invention. In particular, it was surprising that the device according to the invention and the method according to the invention no longer have the disadvantages of the prior art but allowed a particularly efficient transport of the thermal energy from the heat source to a thermoelectric element (TEE) as well as the efficient dissipation of residual thermal energy supplied from the TEE to a heat absorbing or heat dissipating device (heat sink). The selection of the materials used to construct the device according to the invention was subject to less or no restrictions with regard to their thermal expansion coefficients. Nevertheless, in the device according to the invention and in the method according to the invention no or only negligibly small, caused by different thermal expansion coefficients mechanical stresses.

The device of the invention also eliminates the problems of thermal contacting between the source of thermal energy and the hot surface of the TEE and between the cold surface of the TEE and the heat sink. Thus, in prior art devices, effective thermal contact was ensured only by mechanical pressure. As a result, there was the danger that the known devices were already mechanically damaged during assembly or in the course of their use. In addition, the quality and planarity of the respective contact surfaces had to be set high, otherwise the temperature drop between the source of thermal energy and the hot side of the TEE became too high and the efficiency of power generation was lowered.

Overall, the device according to the invention and the method according to the invention have a higher efficiency than the devices and methods of the prior art.

The device according to the invention also had the significant advantage that its components could be combined with one another in a wide variety of spatial arrangements. As a result, the device according to the invention could be adapted to a wide variety of spatial and / or thermal conditions in a particularly flexible manner. In particular, the TEE could be arranged as an electrical component separate from heat dissipating devices containing water or flammable liquids, which made the inventive device and the inventive method particularly safe. In addition, the apparatus and method of the invention allowed the thermal energy to be concentrated to a few TEEs, thus ensuring that the temperature of the hot side of the TEE was always within or near the optimum range and thus the efficiency of power generation remained high ,

Not least, in the device according to the invention and in the method according to the invention, the risk of overheating during operation was significantly reduced, if not completely excluded.

Furthermore, the devices according to the invention were compact, robust and transportable and had a particularly long service life.

Detailed description of the invention

The device according to the invention serves for the direct conversion of thermal energy into electrical energy by means of the Seebeck effect in thermoelectric elements (TEE). In the apparatus according to the invention, at least one, in particular one, apparatus for the flameless catalytic oxidation of hydrocarbons serves as the heat source.

The apparatus for flameless catalytic oxidation of hydrocarbons comprises at least one, in particular a reaction space, which is enclosed by a gas-tight wall. The reaction gases are conducted via at least one inlet device into the reaction space, where they react with each other to the exhaust gases, which are discharged via at least one, in particular an outlet device from the device.

Under oxidation in the context of the present invention, the reaction of a reducing agent with oxygen to understand. For this pure oxygen, with nitrogen and / or noble gases diluted oxygen or air can be used. Preferably, air is used as the source of oxygen. Preferably, the oxidation is carried out at atmospheric pressure. The reducing agents or fuels are hydrocarbons, preferably methane, ethane, propane, butane, isobutane, pentane and its isomers, hexane and its isomers, cyclopentane and cyclohexane, but especially methane. Preferably, natural gas is used as the source of methane.

As is known, the oxidation or combustion of methane proceeds according to the following equation:

CH ₄ + 20 ₂ -> C0 ₂ + 2H ₂ 0

Since methane causes a particularly strong greenhouse effect in the atmosphere, its combustion should be as complete as possible. Without a catalyst this is only possible in a flame at very high temperatures. At these temperatures, however, increasingly toxic nitrogen oxides (NO _x ) and carbon monoxide are formed. In addition, at the necessary high temperatures, the known devices for the direct conversion of thermal energy into electrical energy can be damaged, in particular because the temperature and thus the flow of thermal energy are difficult to control. Complete flameless oxidation of methane to carbon dioxide and water without formation of toxic products is possible at significantly lower temperatures, especially at temperatures of 50 to 400 ° C, with the aid of catalysts.

Preferably, nanoparticles are used as catalysts.

The catalytically active nanoparticles preferably have an average particle size of 2 to 50 nm, preferably 3 to 40 nm, particularly preferably 4 to 30 nm and in particular 5 to 25 nm. The catalytically active nanoparticles contain at least one oxide selected from the group consisting of scandium oxide, yttrium oxide, titanium dioxide, zirconium dioxide, hafnium dioxide, vanadium oxide, niobium oxide, tantalum oxide, manganese oxide, iron oxide, chromium oxide, molybdenum oxide, tungsten oxide, zinc oxide, oxides of lanthanides, preferably lanthanum oxide and cerium oxide, in particular cerium oxide, oxides of actinides, magnesium oxide, calcium oxide, strontium oxide, barium oxide, aluminum oxide, gallium oxide, indium oxide, silicon dioxide, Germanium oxide, tin oxide, antimony oxide, bismuth oxide, zeolites, spinels, mixed oxides of at least two of said oxides, and hydroxyapatite is selected. In particular, alumina, silica, zirconia, zeolites and / or ceria are used.

The oxides and hydroxyapatite may contain other ingredients such as halides, nitrides, phosphides and / or sulfides.

The catalytically active nanoparticles also contain at least one metal selected from the group consisting of vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum , Copper, silver and gold, is selected. Preference is given to using palladium and platinum, in particular palladium. Preferably, the catalytically active nanoparticles contain a metallic core which is surrounded by an oxide shell. The oxide shell is preferably constructed of oxide nanoparticles. Preferably, titanium dioxide, zirconium dioxide and cerium oxide, in particular cerium oxide, are used. Most preferred are those described in M. Cargnello, JJ Delgado Jaen, JC Hernandez Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gämez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ Ce02 Subunits on Functionalized AI2O3 ", used in Science, Vol. 337, pages 713 to 717, 2012, catalytically active nanoparticles composed of palladium nanoparticles coated with ceria nanoparticles (= Pd @ CeO 2).

The catalytically active nanoparticles are part of a catalyst layer which comprises a carrier layer which carries the nanoparticles. The carrier layer can be constructed from a wide variety of materials as long as it does not adversely affect the catalytic activity of the nanoparticles. In addition, the support layer should bind the catalytically active nanoparticles so strongly even at relatively high temperatures that they are not detached by the reaction gases which flow through the reaction space. Preferably, the carrier layer is composed of the above-described oxides or hydroxyapatite. In particular, alumina and / or silica are used. Preferably, the surface of the carrier layer is hydrophobic. This can be accomplished by reacting the hydroxyl groups on the surface of the oxides or hydroxyapatite with a silylating reagent. Preferably, the silylating reagents are selected from the group consisting of dialkoxy (dialkyl), dialkoxy (dicycloalkyl) and dialkoxy (alkylcycloalkyl) silanes, and trialkoxy (alkyl) and trialkoxy (cycloalkyl) silanes.

Examples of suitable dialkoxy (dialkyl), dialkoxy (dicycloalkyl) and dialkoxy (alkylcycloalkyl) silanes are dimethoxy, diethoxy, dipropoxy, diisopropoxy, di-n-butoxy and diisobutoxy (dialkyl) -, - (dicyloalkyl) and (alkylcycloalkyl) silanes in which the alkyl and cycloalkyl radicals are selected from the group consisting of radicals having from 5 to 20 carbon atoms, preferably n-pent-1-yl, isopent-1-yl, n-hex-1 yl, isohex-1-yl, 2-ethylhex-1-yl, cyclohexyl, 1-, 2-, 3- and 4-methyl, ethyl, prop-1-yl, isopropyl, n Butyl-1-yl, sec-but-1-yl and tert-butyl-cyclohex-1-yl, n-hept-1-yl, n-oct-1-yl, isoct- 1-yl, n-o-1-yl, n-dec-1-yl, undec-1-yl, dodec-1-yl, tridec-1-yl, tetradec-1-yl , Pentadec-1-yl, hexadec-1-yl, heptadec-1-yl, octadec-1-yl, nonadec-1-yl and eicosan-1-yl radicals.

Highly suitable trialkoxy (alkyl) and trialkoxy (cycloalkyl) silanes contain alkoxy radicals selected from the group consisting of methoxy, ethoxy, propoxy, isopropoxy and n-butoxy radicals. Preferably, ethoxy radicals are used. The well-suited trialkoxy (alkyl) and trialkoxy (cycloalkyl) silanes also contain one of the above-described alkyl and cycloalkyl radicals. Preferably, the n-oct-1-yl radical is used. Trialkoxy (alkyl) silanes and in particular triethoxy (n-oct-1-yl) silane (TEOOS)) are preferably used as silylating reagents.

The carrier layer is located on a gas-permeable catalyst support. Preferably, the gas-permeable catalyst support is plates which can be constructed from a wide variety of materials. Criteria for selection The materials are heat resistance, mechanical stability and non-combustibility. In particular, plates of iron, in particular stainless steel, and iron alloys, in particular alloys of iron with chromium and / or aluminum, which may also contain lanthanides, in particular cerium, are used.

The plates can have a wide variety of outlines. The outlines depend primarily on the respective outline of the reaction space. Thus, the outline may be triangular, quadrangular, pentagonal, hexagonal and octagonal, optionally with rounded corners and / or sides, as well as circular or elliptical.

The plates can have different thicknesses. Preferably, the thicknesses are in the range of 0.5 to 5 mm, preferably 0.8 to 4.5 mm and in particular 1 to 3 mm.

The plates can also have different diameters. In the case of plates which do not have a square or circular outline, diameter means the longest diameter in each case. Preferably, the diameter is in the range of 1 to 20 cm, preferably 2 to 15 cm and in particular 5 to 10 cm.

The gas permeability is ensured by breakthroughs through the plates. The number, size and shape of the breakthroughs can vary within wide limits. It is essential that down payment and size do not reduce the mechanical stability of the plates. Thus, for example, the apertures may be triangular, quadrangular, pentagonal, hexagonal, circular, elliptical, rectilinear or curved slot-shaped, zigzag-shaped or meander-shaped or as disclosed in Japanese Patent Application JP 2009027876 A in FIGS. 3 (a) -3 (c), 4 ( a0) -4 (a2), 4 (b0) -4 (b2) and 9 (a) -9 (f).

The plates may be arranged concentrically around the heat pipe of the device according to the invention. In this case, the edge of the plate may have a certain distance from the wall of the heat pipe or be directly connected thereto.

The catalytically active nanoparticles can also be constituents of meso and / or macroporous particles which form a fluidized bed in the reaction space. Preferably, the meso and / or macroporous particles of the above-described oxides, in particular alumina and / or silica, and / or Hydroxylapatite built up. Preferably, their surface is rendered hydrophobic in the manner described above.

The diameter of the meso and / or macroporous particles can vary widely and be adapted to the requirements of the respective device according to the invention and of the respective method according to the invention. For meso and / or macroporous particles which have no spherical shape, the diameter is to be understood as the longest diameter. It is essential that the meso and / or macroporous particles are not so large and therefore so heavy that they no longer form a fluidized bed in the reaction space under the conditions of flameless catalytic oxidation. Preferably, the diameter is in the range of 0.1 to 1000 μιτι, preferably 0.2 to 800 μιτι and in particular 0.3 to 600 pm.

Furthermore, the meso and / or macroporous particles may have a broad or narrow, monomodal, bimodal or multimodal particle size distribution. Preferably, a narrow monomodal particle size distribution is used to exclude the disturbing influence of particularly small and particularly large meso and / or macroporous particles, so that substantially uniform reaction conditions are present in the fluidized bed.

The pore size of the meso and / or macroporous particles can also vary widely and be adapted to the requirements of the respective device according to the invention and the respective method according to the invention. It is essential that the pore size is adjusted so that the catalytically active nanoparticles can be incorporated into the pores. The mean pore size is preferably in the range from 10 to 1000 nm, preferably from 20 to 750 nm and in particular from 30 to 500 nm.

Meso and / or macroporous particles can be prepared from meso and / or macroporous ceramics, for example by grinding and sifting the ground products. Meso and / or macroporous ceramics and processes for their preparation are known, for example, from the patents US 2001/0039236 A1, PT 102713 A, US 2009/0162414 A1 and US 2011/0163472 A1 or the publications of Technology License Bureau (TLB) of the Baden-Württembergischen Hochschulen GmbH from the year 2012, »New process with high savings potential: macroporous ceramics and polymer foams from capillary suspensions«, »Macroporous ceramics and polymer foams: the manufacturing process and its advantages« and »Macroporous Ceramics and polymer foams: Examples: AbOs ceramic and PVC polymer foam «known.

If the reaction space contains a fluidized bed of the above-described meso and / or macroporous particles, it is advantageous if the outlet device for the exhaust gases is connected to a device for separating solid particles from the gas phase. Preferably, the deposited solid particles are returned to the reaction space. At least one, in particular one, cyclone is preferably used as the device for depositing solid particles.

The catalytically active nanoparticles can also be part of at least one meso and / or macroporous sintered body.

The at least one meso and / or macroporous sintered body largely or completely fills the reaction space of the apparatus for the flameless catalytic oxidation of hydrocarbons. That is, the shape of the meso and / or macroporous sintered body is determined by the shape of the reaction space.

The at least one meso and / or macroporous sintered body preferably surrounds the area of the at least one heat pipe receiving the thermal energy concentrically.

Preferably, the meso and / or macroporous sintered body of the above-described oxides and / or hydroxyapatite or of metals, in particular chromium or nickel, constructed.

The meso and / or macroporous sintered body preferably has pores whose average pore size is in the range specified above for meso and / or macroporous particles.

The meso and / or macroporous sintered bodies can according to those in the patents US 2001/0039236 A1, PT 102713 A, US 2009/0162414 A1 and US 2011/0163472 A1 or in the publications of Technology License Office (TLB) of Baden - Württembergische Hochschulen GmbH from 2012, »New process with high savings potential: macroporous ceramics and polymer foams from capillary suspensions«, »Macroporous ceramics and polymer foams: The Manufacturing Process and Its Benefits "and" Macroporous Ceramics and Polymeric Foams: Examples: A 03 Ceramic and PVC Polymeric Foam "are disclosed. Furthermore, meso- and / or macroporous sintered bodies from the thesis of Ewald Maria Sütterlin, "Catalytic oxidation for power generation, studies on thermogenerator, gas oxidation and injector burner, Diplomica® Verlag GmbH, ISBN: 978-3-8366-5863-8, 2008 , a catalytic butane diffusion burner as a heat source for TEE «, known.

The at least one, in particular one, reaction space of the at least one apparatus for flameless catalytic oxidation of hydrocarbons, which is defined by its wall, can have different spatial geometries.

Preferably, its length in the direction of the gas flow is greater than its diameter transversely thereto. It comprises a lower region into which the reaction gases, in particular natural gas and air, are introduced via at least one inlet device, and an upper region from which the exhaust gases, in particular water, carbon dioxide and the unused portions of the oxidizing agent, in particular the remaining air, be derived.

Preferably, the reaction space has a length in the range of 5 to 50 cm, preferably 6 to 40 cm, in particular 10 to 30 cm.

The reaction space can have a wide variety of outlines. Thus, the outline may be triangular, quadrangular, pentagonal, hexagonal, octagonal, circular or elliptical. Preferably, the outline is square or circular.

In addition, the reaction space can have different diameters. In the case of a reaction space which does not have a square or circular outline, the term "diameter" is understood to mean the longest diameter in each case. Preferably, the diameter is in the range of 1 to 30 cm, preferably 2 to 25 cm and in particular 3 to 20 cm.

Diameter and contour of the reaction space can vary in the direction of the longitudinal axis. Thus, the lower region can constrict funnel-shaped, while the upper region, in particular in a reaction chamber containing a fluidized bed, itself widens and serves as a separation zone in which meso and / or macroporous particles are separated from the exhaust gases.

The wall of the device for the flameless catalytic oxidation of hydrocarbons, which encloses the reaction space in a gastight manner, is constructed of at least one non-combustible, mechanically and thermally stable material. Examples of suitable materials are metals and ceramics and their composites. In particular, stainless steel is used. The metals can be protected by oxide layers against corrosion and abrasion.

The walls can have a wide variety of outlines. Thus, the outline may be triangular, quadrangular, pentagonal, hexagonal, octagonal, circular or elliptical. The wall can have different strengths. Preferably, the thicknesses are in the range of 0.5 to 10 mm, preferably 0.8 to 8 mm and in particular 1 to 6 mm.

The wall can have different diameters as the reaction space. The term "diameter" is understood to mean the longest diameter in the case of a wall which does not have a square or circular outline. Preferably, the diameter is in the range of 1 to 30 cm, preferably 2 to 25 cm and in particular 3 to 20 cm.

The walls can also have different lengths. Preferably, the length is in the range of 5 to 50 cm, preferably 6 to 40 cm and in particular 10 to 30 cm.

The at least one inlet device for a gas or a gas mixture is likewise constructed from at least one of the non-combustible, mechanically and thermally stable materials described above. Likewise, the at least one outlet device for the exhaust gases can be constructed from at least one of the stated materials.

The at least one apparatus for flameless catalytic oxidation of hydrocarbons further includes a conventional and known peripherals, the usual and well-known pneumatic, mechanical and electronic measuring and control devices, in particular for measuring and controlling the temperature and gas flow, conventional and known pneumatic, mechanical and electronic Devices for the transport of gaseous, liquid and solid materials such as feed pumps and corresponding conventional and known display devices comprises. In addition, the at least one apparatus for flameless catalytic oxidation of hydrocarbons may contain at least one, in particular one, ignition device. Preferably, the ignition device is located in the lower region of the reaction space. As ignition device, conventional and known electric gas igniter can be used.

Preferably, the at least one apparatus for flameless catalytic oxidation of hydrocarbons is thermally isolated. The insulation can consist of a wide variety of mechanically and thermally stable, insulating materials. Preferably, the insulating materials are nonflammable and abrasion resistant. Examples of suitable insulating materials are solid wood, glass and ceramic foams, earthenware and high temperature resistant polymers such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), poly (trifluorochloroethylene) (KEL-F®), polysiloxanes, polysulfones, polyethersulfones, polyetherketones and polyimides. The at least one device for the flameless catalytic oxidation of hydrocarbons is in heat-conducting contact with the thermal energy absorbing region of at least one, in particular one, heat pipe.

As is known, a heat pipe is a fluid-tight and gas-tight sealed component with which thermal energy or heat can be transferred very efficiently from one location to another, i. can be transported over a more or less long connection area from the thermal energy absorbing area to a thermal energy emitting area. The transporting the thermal energy dissipating area is in electrically insulating, thermally conductive contact with the hot side (s) of at least one, preferably at least two, TEE.

Preferably, the connection region is thermally insulated to the outside, wherein preferably the above-described thermally insulating materials are used. The heat pipe can be known to transport a 100 to 1000 times higher heat energy than a component of the same geometric dimensions of solid copper. The heat pipe uses the physical effect that very large amounts of energy are converted when evaporating and condensing a liquid. The heat pipe is hollow inside and filled with a small amount of liquid, the "working" liquid. This is under its vapor pressure, which can be well below the atmospheric pressure at low temperatures. The inner wall of the heat pipe can be covered with a capillary structure - comparable to a wick. This capillary structure is saturated with a liquid heat transfer medium, the working liquid.

If thermal energy is supplied to the thermal energy receiving region of the heat pipe, the working liquid from the capillary structure evaporates there. The steam flows in the direction of the temperature gradient and condenses everywhere, releasing the heat of vaporization, where thermal energy is dissipated. The condensate, the liquefied heat transfer medium, is absorbed by the capillary structure, flows back to re-evaporate. It closes a cycle, which circulates quickly and very effectively transports thermal energy. The temperature difference between the evaporation and condensation zone in the heat pipe is very low, so that the heat conduction is almost isothermal.

Depending on which temperature range (low, medium, high) is used, different working fluids are used, such as water in the temperature range of about 170 to 600K, ammonia in the temperature range of about 150 to 170K, mercury in the temperature range of 400 to 800K or lithium or silver in a temperature range above 1000K. It is essential that the working liquid does not chemically attack and corrode the wall of the heat pipe. The fluid- and gas-tight wall of the heat pipe can be constructed from a variety of materials. For the construction also flexible materials can be used. In addition, the heat pipe can be an integral part of flexible plastic films. The materials of which the heat pipe is constructed, however, must in the temperature range given by the heat source fluid and gas tight, both opposite the working liquid as well as the outer atmosphere chemically stable, mechanically and thermally stable and stable deformation. In addition, the materials should have a high thermal conductivity so that the thermal energy of the heat source can be absorbed and effectively delivered to the hot side of the at least one TEE.

Preferably, the walls of the heat pipes of metals and metal alloys, in particular copper is used. The heat pipe may have different cross sections such as triangles, squares, rectangles, pentagons, hexagons or octagons, which may have rounded corners and / or sides, ellipses, ovals or circles.

The size of the cross sections can vary widely and can be perfectly adapted to the requirements of the device according to the invention and of the method according to the invention. Thus, the cross sections can range from a few microns to several centimeters.

In addition, the heat pipe may have different shapes in the longitudinal direction. Thus, it can be rectilinear, bent in the plane one or more times, spatially multiply bent, meandering or spiraling.

The heat pipe can still be coated after molding to protect it from mechanical, chemical and / or thermal effects. Examples of suitable coating materials are thermal and / or actinic radiation such as UV radiation or electron beam curable, pigmented or non-pigmented powder coatings or water-based or organic solvent-based liquid coatings.

The capillary structure with wicking on the inside of the wall can also be made of a variety of materials. Essential for their selection are the temperature range given by the source of the thermal energy and the stability with respect to the working liquid. In addition, contact between the capillary structure and the wall should not cause corrosion under the influence of the working liquid. The person skilled in the art can therefore select the materials on the basis of the property profiles known to him. The capillary structure can be constructed of nanoparticles, fiber materials or porous materials with appropriately sized pore sizes. In addition, the wicking by wire mesh, such as copper wire mesh or electrically non-conductive wire mesh and fiber bundles, such as ceramic, glass or high temperature resistant plastics, can be generated inside the heat pipe. Furthermore, the wicking effect can also be generated by surface structures of elevations and depressions such as grooves, columns, spheres or cups on the inner wall of the heat pipe. The capillary structure with wicking can also be introduced later. Examples of suitable methods are the crystallization or precipitation of meso and / or macroporous materials such as zeolites or ceramics. The subsequent introduction is particularly advantageous for the "open embodiment" described below, because in this way a direct connection to an electrically insulating, thermally conductive, structured surface on the hot side of the TEE, on which the working fluid condenses, can be accomplished in one step ,

The end of the heat pipe, which is in heat-conducting contact with the heat source, i. The apparatus for the flameless catalytic oxidation of hydrocarbons need not necessarily be electrically isolated therefrom.

Preferably, the heat conductive contact between the end of the heat pipe, i. with the thermal energy absorbing portion, and the heat source by solder contacts, welding contacts, flange contacts, electrically and thermally conductive, metal particle-containing adhesive layers, screw, plug and terminal contacts, in which the end of the heat pipe, i. the thermal energy absorbing area, is screwed into the heat source, plugged or clamped, or by pressure contacts, in which the end of the heat pipe is pressed by means of suitable devices in the heat source made. The heat-conductive contact can also be further improved by electrically conductive and thermally conductive, metal particle-containing thermal compounds.

It is mandatory that the contact of the thermal energy emitting area of the heat pipe with the hot side of the TEE is electrically insulating. In the context of the present invention, the hot side of a TEE is the side which absorbs the thermal energy. The electrical insulation can be, for example, using thermally conductive ceramic layers, thermally conductive plastic layers, for example based on polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), poly (trifluorochloroethylene) (KELF®), polysiloxanes, polysulfones, polyethersulfones, polyether ketones and polyimides or layers Alumina, aluminum nitride and / or silicon nitride are ensured. These layers can be applied to the contact surface by sputtering or applied as wafers. The contact of the heat pipe with the hot side of the thermoelectric element is made by a suitable contact device. The selection of the materials for the construction of the contact device depends in particular on the temperature range predetermined by the heat source. Preferably, the contact or fastening device comprises heat-conducting solder contacts, welding contacts, flange contacts, adhesive layers, screw, plug and terminal contacts, in which the end of the heat pipe in or on or on the hot side located corresponding complementary devices or screwed, plugged or a - or is clamped. The thermal conductivity can be further improved by the use of thermal compounds, for example thermal pastes based on silicones.

If fastening devices such as flange contacts are used, these can be fastened on electrically and thermally insulating anchoring parts.

Preferably, these anchoring parts consist of a solid, electrically and thermally not or only poorly conductive, mechanically and thermally stable material. Examples of suitable materials of this type are wood and polymers such as polytetrafluoroethylene (PDFE), polyvinylidene fluoride (PVDF), poly (trifluorochloroethylene) (KEL-F®), polysiloxanes, polyethersulfones, polyetherketones and polyimides.

The anchoring parts may consist of one piece or be composed of several parts. Preferably, the sides of the anchoring parts abut flush with the vertical sides of the TEE so that they additionally insulate it. Preferably, the opposing surfaces of the anchoring members are each in a plane with the surfaces of the hot and cold sides of the TEE. If the anchoring parts are composed of several parts, they can have pegs and complementary recesses in and on the abutting sides, which further stabilize the assembled anchoring parts.

In addition, the anchoring parts as well as the parts of the composite anchoring parts with each other and with the vertical sides of the TEE, with the above-described, protruding electrically insulating, thermally conductive layer, optionally described hereinafter, electrically conductive, gas and fluid-tight seal and / or the resting Surface of the flange contact to be bonded with a thermostable, electrically insulating adhesive. As a result, in particular the mechanical stability and the thermal insulation of the TEE and the heat pipe are further improved. Preferably, the flange contacts are still attached by mechanical fastening devices such as clamps, screws or pins and complementary recesses on the anchoring parts.

If these contact devices are still electrically conductive, the contact device comprises the above-described electrically insulating, heat-conducting layers. These layers are located directly on the hot side of the TEE. In general, they only need a few nuclear facilities to be strong. In order to enable soldering and welding, the heat-conductive insulating layers are covered on their outside with a thin metal layer.

A particularly advantageous arrangement of this kind can be produced by sputtering a metal oxide layer, which gradually merges into a metal layer.

In a particularly preferred embodiment of the device according to the invention, the thermal energy emitting area of the at least one heat pipe has at least one opening, preferably at least two openings. Thereby, the electrically insulating, heat-conducting contact is designed so that the hot side of the at least one TEE is in direct contact with the interior of the heat pipe, so that the working liquid condenses directly on the hot side and the thermal energy is transmitted directly. Hereinafter, this embodiment will be referred to as "open embodiment". In the open embodiment, the condensation of the working fluid and the transfer of thermal energy can be further improved by means of a structured surface on the hot side, which is in direct contact with the interior of the heat pipe. The structured surface may be composed of nano-, meso- and / or macroporous materials, nanoparticles or groove structures. If the structured surface is still electrically conductive, it is electrically insulated from the hot side by one of the electrically insulating, thermally conductive layers described above.

The return of the condensed working fluid to the other end of the heat pipe, i. to the heat energy source in contact with the thermal energy receiving portion of the heat pipe can be done by gravity. For this, the heat pipe must be arranged vertically.

However, the return can also be due to the wicking of inserted electrically non-conductive wire mesh and fiber bundles, as described above, take place. These electrically non-conductive wire meshes and fiber bundles are arranged to be in direct contact with the condensed working fluid. In this embodiment, the heat pipe can be arranged arbitrarily spatially.

In the ^" open" embodiment, the contactor further includes a fluid tight, gas tight, adhesive, electrically insulating seal between the wall of the heat pipe and the hot side of the TEE, which does not have to be heat conductive, but can also be electrically conductive unless electrically conductive The easiest way to accomplish this is to make the surface of the electrically insulating, thermally conductive layer described above slightly larger than the hot side of the TEE, so that the surface An example of a suitable, gas- and fluid-tight, adherent, electrically conductive seal is filled with metal particles, in particular copper particles, filled silicone polymers, in particular PDMS. These seals may have different shapes depending on the arrangement and cross section of the heat pipe on the one hand and the outer shape of the or the TEE on the other hand. Preferably, the gaskets are rectangular, square or polygonal, for example hexagonal, or round or elliptical, when the heat pipe has the correspondingly shaped cross section and / or the TEE has the correspondingly shaped surface. In addition, the seal of the planarity of the surface of the TEE may be adapted, for example, if it is bent outwards or inwards and / or has a regular or not regular roughness.

On both sides of the TEE are also the contact areas to which the two different thermoelectric materials of the TEE are electrically connected to each other. The TEE may be electrically conductively connected to at least one other TEE. But it can also be 100 and more such TEE connected in parallel and / or in series. In this case, it is also referred to as a "thermopile." Electrical connections are attached to the electrically positive and electrically negative end of the TEE or the thermopile, which can be connected to a device that operates on the recovered power.

In general, there are three temperature ranges when operating TEE

Low temperature range, i. Temperatures up to 250 ° C,

Medium temperature range, i. Temperatures up to 600 ° C and

High temperature range, i. Temperatures up to 1000 ° C. Depending on the temperature range in which work, different materials are used in the device according to the invention. The choice can be made by a person skilled in the art on the basis of the known chemical and physical properties of the materials. Preferably, work is carried out in the low-temperature range.

Those for the legs of the TEE that are brought into electrical contact with each other on the hot side are selected according to their figure-of-merit Z in accordance with Equation XII.

Equation XII Z = σα ² / λ.

In equation XII, α stands for the Seebeck coefficient, σ is the electrical conductivity, and λ is the thermal conductivity of the material in question.

Preferably, p- and n-doped semiconductor materials are used.

Preferably, bismuth telluride alloys (Bi ₂ Te ₃ ) are used for the low temperature range.

Preferably, lead telluride (PbTe) is used for the medium temperature range.

Preferably, silicon germanium alloys and Zintl alloys are used for the high temperature range.

Further examples of suitable semiconducting materials are known from US patent application US 2010/0229911 A1, page 1, paragraphs [0003] to [0011], or from US patent US 5,610,366, column 2, page 27, to column 3, page 32 ,

Preferably, bismuth telluride alloys are used.

Conventional and known, commercially available TEEs can be used in the devices according to the invention. The term "thermoelectric element" in this case comprises a single TEE or an arrangement of several series or parallel connected TEEs in the form of a so-called thermopile.

Examples of suitable TEEs are described in detail in US patent US 5,610,366, US patent application US 2010/0229911 A1, international patent application WO 97/44993 A1, German patent application DE 101 12 383 A1 or the company publication of Hi-Z Technology Inc., "Use, Application and Testing or Hi-Z Termoelectric Modules", authors: FA Levitt, NB Eisner and JC Bass, described.

Preferably thermoelectric modules are used in "eggcrate" configuration (egg-box configuration), as for example in the international patent application WO 97/44993, page 2, last paragraph, to page 5, last paragraph, in conjunction with the Figures 1A to 14 and 27 will be described. In particular, the modules Hi-Z 20, Hi-Z Technology Inc., USA, are used in the devices according to the invention. In the device according to the invention, one or more TEEs can be thermally contacted simultaneously.

In the devices according to the invention, the cold side of the at least one TEE facing the hot side is in electrically insulating, thermally conductive contact with a heat dissipating device (heat sink). This serves to dissipate and optionally use the remaining supplied thermal energy.

In a preferred embodiment, this contact is accomplished by at least one additional heat pipe. In the following, the additional heat pipe is referred to as a "second heat pipe".

The second heat pipe is in one of its ends in electrically insulating, thermally conductive contact with the cold side of the TEE and at its other end in thermally conductive contact with the heat dissipating device. Preferably, the above-described heat pipes and contact devices are used. Since the heat pipes and cold side contact devices of the TEE are exposed to lower temperatures than those of the hot side of the TEE, materials other than the hot side may be used.

In a further preferred embodiment, this contact is produced by at least one electrically insulating, thermally conductive layer. For their construction, the above-described electrically insulating, thermally conductive materials can be used.

The heat-dissipating devices or heat sinks can be of very different nature and of very different construction.

In the context of the present invention, air and water are heat-dissipating devices in the sense of the invention. Preferably, the rest is supplied transfer thermal energy via cooling fins made of metal to the air or water. Accordingly, cooling fins are also heat sinks in the sense of the present invention.

Preferably, however, the heat-dissipating devices are devices that allow the use of the remaining supplied thermal energy. These are particularly preferably heat exchangers, tube cooling bodies, in particular tube cooling bodies for solar thermal systems, motors, turbines or systems for carrying out the Rankine cycle, in particular the organic Rankine cycle, in which comparatively low-boiling organic liquids are used as the working medium. In addition, heat radiating radiators and large area heaters that can be installed under walls, ceilings, or floors indoors and outdoors of buildings can be considered as heat sinks. Furthermore, devices of the invention constructed in this manner may self-operate or assist in their operation of their water-consuming and water-circulating pumping systems.

The electric current generated by the TEEs of the devices of the invention can be used for a variety of purposes. So he can support the operation of the devices according to the invention itself. Likewise, it can assist in the operation of the heat sinks that utilize the residual applied thermal energy as well as the operation of their peripherals. Examples include electrically operated pumps, chillers that protect the sources of thermal energy from overheating, and motors. Likewise, the power can be used to charge electrical storage such as batteries, accumulators and electric storage heaters. Overall, the use of waste heat in this way results in significant energy savings.

However, the power can also be used for the operation of external electrical devices of various kinds such as lighting systems, refrigerators and freezers, air conditioners, heat pumps, circulating pumps, consumer electronics, communication devices such as telephones or mobile phones, computers, laptops or iPads.

In the method according to the invention for the direct conversion of thermal energy into electrical energy, the thermal energy supplied by a heat source is at least one of the hot sides by means of at least one heat pipe a TEE transported, wherein in the TEE an electrical voltage is generated. The remaining applied thermal energy is supplied from the cold side of the TEE via an electrically insulating, thermally conductive contact at least one heat sink.

Preferably, the above-described inventive devices are used for the inventive method.

It is a very particular advantage of the device according to the invention and of the process according to the invention that with their help the complete, flameless catalytic oxidation of hydrocarbons at comparatively low temperatures, preferably at 50 to 400 ° C, preferably 100 to 350 ° C and especially 150 to 300 ° C can be performed. The exhaust gases therefore contain no hydrocarbons, especially no methane acting as a greenhouse gas, and no harmful nitrogen oxides (NO _x ) more, or the content of the exhaust gases to these harmful substances is below the detection limits of their usual and known qualitative and quantitative detection methods.

The device 1 according to the invention will be explained below by way of example with reference to FIGS. 1 to 13. Figures 1 to 13 are schematic representations intended to illustrate the principle of the invention. The size ratios must therefore not correspond to the size ratios used in practice. 1 shows the construction and operation principle of a device 1 according to the invention, wherein the device for flameless catalytic oxidation via a heat pipe is electrically insulated and thermally conductively connected to the hot sides of at least two TEE and the cold sides of the at least two TEE in electrically insulating, thermally conductive Contact with at least one heat-dissipating device or heat sink is.

FIG. 2 shows the principle of construction and operation of another device 1 according to the invention, in which the apparatus for flameless catalytic oxidation is electrically insulated via a heat pipe and thermally conductively connected to the hot sides of at least two TEEs and the cold sides of the at least two TEEs are electrically insulated, thermally conductive contact with at least two others Heat pipes stand, which conduct the remaining heat to at least one heat sink.

Figure 3 shows the principle of construction and operation of a further device 1 according to the invention in monolithic construction, wherein the device for flameless catalytic oxidation of hydrocarbons via a heat pipe is electrically insulated and thermally conductively connected to the hot sides of at least two TEE and the cold sides of at least two TEE are in electrically insulating, thermally conductive contact each with at least one heat sink.

Figure 4 shows a section along the line AA through the inventive device 1 according to Figure 3, wherein the hot sides of four TEE in thermally conductive, electrically insulating contact with a heat pipe and the cold sides of the TEE in thermally conductive, electrically insulating contact with each stand at least one heat sink.

FIG. 5 shows a section along the line B-B through the device 1 according to the invention, according to FIG. 3, in which the thermal energy absorbing region of the heat pipe is in thermal contact with at least one gas-permeable catalyst support in the reaction space of the apparatus for flameless catalytic oxidation of hydrocarbons.

FIG. 6 shows an enlarged section of the longitudinal section through the device 1 according to the invention in the area of the apparatus for flameless catalytic oxidation of hydrocarbons with at least three gas-permeable catalyst carriers surrounding the thermal energy-receiving region of the heat pipe concentrically.

FIG. 7 shows an enlarged section of a region of the gas-permeable catalyst support according to FIG. 6 with a gas passage.

FIG. 8 shows a further enlarged section of a region of the gas-permeable catalyst support according to FIG. 7 with the catalytic surface. FIG. 9 shows an enlarged detail of the fastening region of the heat pipe of the device 1 according to the invention according to FIG. 3. FIG. 10 shows a further enlarged detail of the fastening region of the heat pipe of the device 1 according to the invention according to FIG. 3. FIG. 11 shows the side view of the heat pipe of the device 1 according to the invention according to FIG. 3 in the direction of the mounting flanges and the opening.

FIG. 12 shows a further advantageous embodiment of the device 1 according to the invention, in which a fluidized-bed reactor with cyclone is used for the flameless catalytic oxidation of hydrocarbons.

FIG. 13 shows a device for the flameless, catalytic oxidation of hydrocarbons, wherein the reaction space contains at least one macroporous sintered body.

In FIGS. 1 to 13, the reference symbols have the following meaning:

1 Device according to the invention for direct conversion of thermal

Energy into electrical energy

2 Apparatus for flameless catalytic oxidation of

hydrocarbons

2.1 reaction space

2.2 gas inlet

2.3 reaction gases

2.4 Gas outlet

2.5 exhaust gases

2.6 Wall of the reaction space

2.7 gas-permeable catalyst support

2.8 Gas passage

2.9 passing gases

2.10 catalyst layer

2.10.1 Carrier layer

2.10.2 Catalytically active nanoparticles

2.11 fluidized bed

2.11.1 macroporous particles with catalytically active nanoparticles 2.12 discharged and returned macroporous particles

2.13 Separation zone

2.14 macroporous sintered body

2.14.1 pores

2.14.2 disc-shaped, macroporous sintered body

2.14.3 Gas distributor

3 heat pipe

3a, 3b heat pipes

3.1 connection area

3a.1, 3b.1 connection areas

3.2 wall

3a.2, 3b.2 walls

3.3 thermal energy absorbing area

3a.3, 3b.3 thermal energy absorbing areas

3.4 thermal energy emitting area

3a.4, 3b.4 thermal energy emitting areas

3.5, mounting flange

3a.5, 3b.5 mounting flanges

3.6 angular strut

3a.6, 3b.6 angular struts

3c.6, 3d.6 angular struts

4 thermoelectric element (TEE)

4a, 4b thermoelectric elements (TEE)

4c, 4d thermoelectric elements (TEE)

4.1 hot side of the TEE

4a.1, 4b.1 hot sides of the TEE

4c.1, 4d.1 hot sides of the TEE

4.2 cold side of the TEE

4a.2, 4b.2 cold sides of the TEE

4c.2, 4d.2 cold sides of the TEE

5 heat sink

5a, 5b heat sinks

5c, 5d heat sinks 5a.1, 5b.1 blocks of thermally conductive material

5c.1, 5d.1 blocks of thermally conductive material

5a.2, 5b.2 channels for heat-absorbing fluid

5c.2, 5d.2 channels for heat-absorbing fluid

5a.3, 5b.3 connecting pipes

5c.3, 5d.3 connecting pipes

5.4 Fluid

6 electrical connection

6a, 6b electrical connections

7 heat-insulating material

8 ignition device

8.1 heated catalyst plates 2.7

9 flowing fluid

10 electrically conductive seal

10a, 10b electrically conductive seals

10c, 10d electrically conductive seals

1 1 electrically insulating, thermally conductive layer

1 1a, 1 1 b electrically insulating, thermally conductive layers

1 1c, 1 1 d electrically insulating, thermally conductive layers

11.1 structured surface

11 a.1, 1 1 b.1 structured surfaces

1 1 c.1, 1 1d.1 structured surfaces 12 electrically insulating, thermally conductive layer

12a, 12b electrically insulating, thermally conductive layers

12c, 12d electrically insulating, thermally conductive layers

13 electrically and thermally insulating anchoring part for at least one fastening device 14th electrically and thermally insulating anchoring part for at least one fastening device 14 and angular, electrically and thermally insulating connecting parts between two electrically and thermally insulating anchoring parts

angular, electrically and thermally insulating connecting parts 13 between two electrically and thermally insulating anchoring parts 13

screw

screw head

washer

thread

Senkschraubenkopf

Through hole with internal thread

cyclone

Recirculation device

exhaust pipe

Exhaust gases first section line through the device 1 according to the invention second section line through the device 1 according to the invention

Longitudinal axis of the device 1 according to the invention. FIG. 1 illustrates the general construction and functional principle on the basis of a longitudinal section through the device 1 according to the invention.

The reaction gases 2.3, in the present case air and natural gas, were fed to the reaction space 2.1 of the heat source 2 via the inlet device 2.2. The ratio of air to natural gas has been adjusted here and in the embodiments described below so that the natural gas could be completely oxidized, ie burned. The reaction space 2.1 was surrounded by the wall 2.6 gas and fluid-tight. In the reaction space 2.1, the natural gas was oxidized by means of atmospheric oxygen to a catalyst completely flameless at 250 ° C. The exhaust gases 2.5 of the oxidation, in the present case carbon dioxide, water and unused air, were passed out of the reaction space 2.1 via the outlet device 2.4. The region 3.3 of the heat pipe 3, which received the thermal energy supplied by the heat source 2, projected into the reaction space 2.1. The heat pipe 3 was completely enclosed by the gas- and fluid-tight wall 3.2. As a result of the absorbed thermal energy, the working liquid of the heat pipe 3, in the present case water, was vaporized and fed via the connecting region 3.1 to the region 3.4 which gives off the thermal energy. There, the working liquid condensed on the hot sides 4a.1 and 4b.1 of the two TEEs 4a and 4b. The absorbed thermal energy flowed from the two hot sides 4a.1 and 4b.1 to the two cold sides 4a.2 and 4b.2, thereby generating in the TEEs 4a and 4b a voltage applied to the two electrical terminals 6a and 6b could be tapped. The remaining thermal energy was then supplied from the cold sides 4a.2 and 4b.2 to the two heat sinks 5a and 5b. FIG. 2 illustrates the construction and operating principle of a preferred embodiment with reference to a longitudinal section through the device 1 according to the invention.

In the apparatus 1 according to the invention according to FIG. 2, the apparatus 2 for the flameless catalytic oxidation of methane likewise has an inlet device 2.2 made of stainless steel for air and natural gas as reaction gases 2.3. In the reaction chamber 2.1 enclosed by the wall 2.6 of stainless steel, the natural gas was catalytically oxidized completely flamelessly at 250 ° C. by the atmospheric oxygen. The exhaust gases were discharged via the outlet device 2.4 stainless steel from the reaction chamber 2.1. The thermal energy supplied by the heat source 2 was received by the thermal energy absorbing portion 3.3 of the heat pipe 3. The wall 3.2 of the heat pipe 3 was made of copper and was 3 mm thick. The heat pipe 3 contained a capillary structure formed of electrically insulating ceramic fibers (not shown). Water was used as working liquid. The operating temperature of the heat pipe 3 was 250 ° C.

The absorbed thermal energy was supplied via the bent at an angle of 90 ° connecting portion 3.1 by the working liquid to the thermal energy-emitting area 3.4. There, the water condensed on the two hot sides 4a.1 and 4b.1 of the two TEEs 4a and 4b. When. TEE 4a and 4b have been used in the embodiment of the inventive device 1 according to the figure 2, two thermopile TEE in 'eggcrate' configuration (egg-box configuration), as described for example in International Patent Application WO 97/44993, page 2, last paragraph to page 15, last paragraph, in connection with Figures 1A to 14 and 27. In particular, the modules Hi-Z 20, Hi-Z Technology, Inc., USA, were used in the devices 1 according to the invention.

Both thermopiles 4a and 4b had electrical terminals 6a and 6b.

Their cold sides 4a.2 and 4b.2 were each covered by an electrically insulating, thermally conductive layer 11a and 11b of aluminum nitride. The layers 11a and 11b formed the contact surfaces with the remaining thermal energy absorbing portions 3a.3 and 3b.3 of the two bent at an angle of 90 ° heat pipes 3a. and 3b with the walls 3a.2 and 3b.2. These heat pipes had the same structure as the heat pipe 3.

The recorded residual thermal energy was conducted via the two transitional regions 3a.1 and 3b.1 to the thermal energy absorbing regions 3a.4 and 3b.4. These were in thermal contact with the two heat sinks 5a and 5b.

The heat sinks 5a and 5b were made of solid aluminum blocks containing channels for heat-absorbing fluids, here deionized water (not shown).

The entire apparatus 1 according to the invention according to FIG. 2 was enveloped by a heat-insulating material 7 except for the two heat sinks. As the heat-insulating material 7 glass foam was used. On the basis of the embodiment according to FIG. 2, it has been shown that the device 1 according to the invention allowed in a particularly advantageous manner the spatial arrangement of the essential components without impairing the function of the device 1 according to the invention. FIG. 3 illustrates the principle of construction and operation of another preferred embodiment of the device 1 according to the invention on the basis of its longitudinal section along its longitudinal axis L. The device 1 according to FIG. 3 had a particularly advantageous compact construction. Air and natural gas were passed as reaction gases 2.3 via the stainless steel inlet device 2.2 into the reaction chamber 2.1 of the apparatus 2 for flameless catalytic oxidation. The reaction space 2.1 was completely enclosed gas-tight and fluid-tight by a cylindrical wall 2.6 made of 4 mm thick stainless steel. The exhaust gases 2.5 · were led out of the reaction space 2.1 via the outlet device 2.4. The diameter of the reaction chamber 2.1 was continuously at 10 cm, its height at 15 cm.

The reaction space contained a plurality of paralyzed catalyst supports 2.7 of an iron-chromium-aluminum alloy arranged concentrically around the thermal energy absorbing portion 3.3 of the heat pipe 3. They had a diameter of 9.9 cm, a circular outline , a thickness of 2 mm and in the middle of a wall 3.2 of the heat pipe 3 circumferential bore. They stood to the longitudinal axis L at an angle of 90 °. They were arranged so that their edges touched neither the wall 3.2 of the heat pipe 3 nor the wall 2.6 of the heat source 2. The uppermost gas-permeable catalyst support 2.7 was arranged below the outlet direction 2.4, so that in the upper region of the reaction space 2.1 an open zone was located, which allowed better dissipation of the reaction gases 2.5. The catalyst supports 2.7 were held in this arrangement by a linkage (not shown).

In the lower region of the reaction chamber 2.1, a plurality of gas-permeable catalyst supports 8.1 were arranged below the lower end of the heat pipe 3 but above the inlet device 2.2, which were constructed and arranged substantially like the catalyst supports, except that they had no bore in their middle. Instead, they were connected to an ignition device 8, by means of which the catalyst supports 8.1 were brought to the ignition temperature for the reaction gases 2.3 flowing into the reaction space 2.1. After starting the flameless catalyzed oxidation of natural gas, this ran throughout the entire reaction space 2.1 without the Supply of energy from the outside self-sustaining, so the ignition device 8 could be turned off.

The catalyst supports 2.7 and 8.1 had narrow slot-shaped gas passages 2.8 (see FIG. 5). Further details of the catalyst supports 2.7 can be found in FIGS. 6 to 8.

The thermal energy absorbing portion 3.3 of the heat pipe 3 was arranged centered in the reaction chamber 2.1 in the central bores of the gas-permeable catalyst carrier. Above the reaction space 2.1 was followed by the connection area 3.1 of the heat pipe 3, through which the absorbed thermal energy was transported by means of the working liquid in the thermal energy emitting area 3.4. The areas 3.1 and 3.3 were together 20 cm long and had a circular cross section with a diameter of 3 cm. The thickness of the wall 3.2 made of copper was 3 mm. The areas 3.1, 3.3 and 3.4 were filled with a capillary structure formed from electrically insulating ceramic fibers (not shown).

At the upper end of the connecting region 3.1, the thermal energy emitting region 3.4 of the heat pipe 3 followed. The upper, circular opening of the connection area 3.1 was located in the middle of the bottom of the thermal energy emitting area 3.4. The area 3.4 itself had a cuboid geometry with square cross section with the following edge lengths: height: 10 cm; Width: 8 cm; on. At the upper end and at the bottom of the region 3.4, the wall 3.2 merged into the peripheral fastening flanges 3a.5 and 3b.5 (for further details see FIGS. 4, 9 and 10). The mounting flanges 3a.5 and 3b.5 were arranged vertically to the horizontally extending wall 3.2 at the end and at the bottom of the area 3.4 and had a vertical height of 2 cm.

The mounting flanges 3a.5 and 3b.5 were on their entire side surfaces in full surface planar Kpntakt with a circumferential, solid, electrically and thermally insulating anchoring part 13 (see the sections: 13a and 13b) for screws 14 (for further details see FIGS. 9 and 10). The anchoring parts 13a and 13b had a rectangular cross section with a height of 3 cm. Their width was equal to the thickness of the TEE 44a and 4b plus the thickness of the electrically insulating, thermally conductive layers 12a and 12b. The upper and lower surfaces of the anchoring parts 13a and 13b are flush with the upper and lower surfaces of the peripheral mounting flanges 3a.5 and 3b.5, respectively, so that the opposite ends each protrude 0.5 cm into the openings in the wall 3.2. The anchoring parts 13a and 13b were made of PTFE.

The wall 3.2 of the area 3.4 had four centered rectangular openings of dimensions: height: 10 cm; Width 6 cm; so that the wall 3.2 of the bottom of the area 3.4 was connected to the wall 3.2 of its upper end by means of four vertical, 10 cm long, angle-shaped struts 3.6 (not shown, see FIG. The four angular struts 3.6 were thus an integral part of the wall 3.2.

In the region of the edges of the rectangular openings, the electrically conductive, gas-tight and fluid-tight seals 10a and 10b were arranged on the basis of copper-filled polydimethylsiloxane (PDMS), which sealed the thermal energy-releasing region 3.4 to the outside. They are flush with the surface of the electrically and thermally insulating anchoring parts 13a and 3b and with the edges of the electrically insulating thermally conductive layers 11a and 11b on the basis of PDMS comprising the hot sides 4a.1 and 4b.1 of the TEEs 4a and 3b 4b covered, off. In this way, it was ensured that the TEEs could not make electrical contact with the wall 3.2 and the gaskets 10a and 10b.

The electrically insulating, thermally conductive layers 11a and 11b had on their surfaces, which were facing the interior of the region 3.4, structured surfaces 11a.1 and 11b.1 of thermally conductive nanoparticles.

The electric wires connecting the TEEs 4a and 4b to the electric terminals 6a and 6b were passed through the upper anchoring parts 13a and 13b.

The cold sides 4a.2 and 4b.2 were covered with the electrically insulating, thermally conductive layers 12a and 12b of aluminum nitride. These were in direct contact with the heat sinks 5a and 5b. These were formed by aluminum blocks 5a.1 and 5b.2, which had channels 5a.2 and 5b.2 for circulating water as heat-absorbing fluid. Except for the heat sinks 5a and 5b, all components of the device 1 according to the invention according to FIG. 3 with glass foam 7 were thermally insulated.

The device of Figure 3 was compact, robust, storable, transportable, reliable and long service life. The yield of electric current was significantly higher than corresponding prior art devices. Likewise, the use of the thermal energy supplied by the heat source 2 was particularly effective.

FIG. 4 illustrates the principle of construction and operation of the preferred embodiment of the device 1 according to the invention according to FIG. 3 with reference to the section along the line A-A in FIG. 3.

As described above, the upper end of the connecting portion 3.1 of the heat pipe 3 opened to the thermal energy releasing portion 3.4.

The thermal energy dissipating region 3.4 was mainly limited by the four electrically insulating, thermally conductive layers 11a, 11b, 11c and 11d, which were fitted in the four openings through the wall and flush with the electrically conductive seals 10a, 10b, 10c and 10d and the hot sides 4a.1, 4b.1, 4c.1 and 4d.1 abut. The layers 11a, 11b, 11c and 11d carried on their surface facing the interior of the region 3.4 the structured surfaces 11a, 1, 11b.1, 11c.1 and 11d.1.

The gaskets 10a, 10b, 10c and 10d were designed such that each gasket 10a, 10b, 10c and 10d abuts the inner surface of the vertical, angular struts and the edges of two adjacent electrically insulating, thermally conductive layers 11a, 11b, 11c and 11c 11d flushed.

Along each angle-shaped strut 3a.6, 3b.6, 3c.6 and 3d.6 was a solid, angular, thermally and electrically insulating connecting part 13a, 13b, 13c and 13d between the two anchoring parts 13a and 13b, which are the mounting flanges 3a. 5 and 3b.5 enclosed, accurately arranged. The connecting parts 13a, 13b, 13c and 13d, like the two anchoring parts 13a and 13b, were made of PTFE. The abutting surfaces of the two connecting parts 13a, 13b, 13c and 13d and the two anchoring parts 13a and 13b had pegs and complementary ones Recesses to increase the mechanical strength of the arrangement on (not shown).

The connecting parts 13a, 13b, 13c and 13d were flush and fit to the side surfaces of the TEEs 4a, 4b, 4c and 4d. The strength of the connecting parts 13a, 13b, 13c and 13d corresponded exactly to the thickness of the TEE 4a, 4b, 4c and 4d.

The cold sides 4a.2, 4b.2, 4c.2 and 4d.2 were covered with the electrically insulating, thermally conductive layers 12a, 12b, 12c and 12d. They conducted the remainder of the thermal energy conducted through the TEEs 4a, 4b, 4c and 4d into the heat sinks 5a, 5b, 5c and 5d, which consisted of solid aluminum blocks 5a.1, 5b.1, 5c.1 and 5d.1 , These contained the channels 5a.2, 5b.2, 5c.2 and 5d.2 for the circulating water 5.4. The connection of these channels from heat sink to heat sink was made through the connecting pipes 5a.3, 5b.3, 5c.3 and 5d.3. They consisted of a thermally insulating plastic. The channels 5a.2, 5b.2, 5c.2 and 5d.2 and the connecting pipes 5a.3, 5b.3, 5c.3 and 5d.3 were arranged so that the water 5.4 guided in a spiral through the heat sinks could be. The inlet of the water 5.4 was located at the upper part of one of the heat sinks 5 and the outlet of the heated water 5.4 at the lower part of the same or another heat sink 5.

FIG. 5 illustrates the principle of construction and operation of the preferred embodiment of the device 1 according to the invention in accordance with FIG. 3 with reference to the section along the line B-B in FIG. 3.

The thermal energy absorbing portion 3.3 of the heat pipe 3 with the wall 3.2 was centrally located in the enclosed by the wall 2.6 reaction space 2.1 of the heat source 2 and was in thermal contact with the gas-permeable catalyst support 2.7. The thermal catalyst carrier 2.7 consisted of an aluminum-iron-chromium alloy and had slit-shaped gas passages 2.8. The wall 2.6 was surrounded by the heat-insulating material 7.

FIGS. 6 to 8 illustrate the principle of construction and operation of the preferred embodiment of the device 1 according to the invention in accordance with FIG. 3 with the aid of enlarged sections of its section along the longitudinal axis L in FIG. 3. FIG. 6 shows a detail of the heat-insulating material 7, the heat source 2 with the wall 2.6, the reaction space 2.1, the gas-permeable catalyst support 2.7 with the gas passages 2.8, through which the reaction gases 2.9 flowed, the heat pipe 3 with the wall 3.2 and the thermal energy receiving area 3.3.

FIG. 7 shows an enlarged section of the arrangement according to FIG. 6 with the gas passage 2.8 of a gas-permeable catalyst support 2.7. The surface of the catalyst support was completely covered with the catalyst layer 2.10. The catalyst layer 2.10 consisted of a carrier layer 2.10.1, which was essentially composed of aluminum oxide. The surface of the carrier layer 2.10.1 was hydrophobicized with TEOOS and calcined after the application of the catalytically active Pd @ CeO 2 nanoparticles. FIG. 8 shows the enlarged section of the arrangement according to FIG. 7 with the catalyst layer 2.10, which consisted of the carrier layer 2.10.1 and the catalytically active nanoparticles 2.10.2. The nanoparticles 2.10.2 were Pd @ Ce02 according to the article by M. Cargnello, JJ Delgado Jaen, JC ernändez Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gämez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ Ce2 Subunits on Functionalized Al ₂ 0 ₃ ", in Science, Vol. 337, pp. 713-717, 2012.

The flameless catalytic oxidation of natural gas by air was excellently catalyzed by the Pd @ Ce02 nanoparticles 2.10.2, so that the reaction was complete even at 250 ° C.

Figures 9 and 10 illustrate the construction and operation principle of the preferred embodiment of the device 1 according to the invention according to the figure 3 with reference to enlarged sections of its section along the longitudinal axis L in Figure 3.

FIGS. 9 and 10 show sections with a TEE 4 with the hot side 4.1 and the cold side 4.2. The hot side 4.1 was covered by the electrically insulating, thermally conductive layer 11. This had the structured surface 11.1. The edge of the layer 11 abutted the electrically conductive seal 10. The cold side 4.2 of the TEE was covered by the electrically insulating, thermally conductive layer 12. At this was followed by the heat sink 5 with the massive aluminum block 5.1 and the channels 5.2 for the circulating water (reproduced only in FIG. 9).

The side surface of the TEE was accurately connected to the solid, electrically and thermally insulating anchoring part 13. Through this, the electric wires ran from the side surface of the TEE to the electric terminal 6.

The solid, electrically and thermally insulating anchoring part 13, in its lower region, fitted precisely to the edge of the seal 10 and to the region of the layer 11 projecting beyond the hot surface 4.2. At its heat sink 5 opposite side surface, it was connected to the mounting flange 3.5 of the wall 3.2.des the heat pipe 3.

The connection was made with a through the through hole with internal thread 14.5 out, a threaded 14.3 having screw 14, which had been screwed into the anchoring part 13, accomplished. In the embodiment of FIG. 9, a screw 14 with a screw head 14.1 and a washer 14.2 was used. In the embodiment of Figure 9, a screw 14 was used with a countersunk head 14.4.

FIG. 11 illustrates the construction and operating principle of the preferred embodiment of the inventive device 1 according to FIG. 3 with the side view of the heat pipe 3. The heat pipe 3 had the wall 3.2 with the thermal energy absorbing area 3.3 and the connection area 3.1. The wall 3.2 had in the area of the thermal energy emitting area 3.4 centered a rectangular breakthrough in the dimensions: height: 10 cm; Width: 6 cm; auf, which received the electrically insulating, thermally conductive layer 11 and the circumferential electrically conductive seal 10. Above and below the breakthrough, the wall went 3.2 in the two vertical mounting flanges 3.5 with the through holes 14.5 with internal thread for receiving the screws 14 on. To the left and right of the aperture, the vertical angular struts 3.6 were arranged, which also merged into the vertical mounting flanges 3.5. The visible sides of the vertical angled struts 3.6 had a height of 10 cm and a width of 1 cm. FIG. 12 illustrates the principle of construction and operation of another preferred embodiment of the device 1 according to the invention on the basis of its longitudinal section

The inventive device 1 according to FIG. 12 had a fluidized bed reactor 2 with a length of 25 cm, a 5 mm thick wall 2.6 made of stainless steel and a circular cross section. In its lower region, the wall 2.6 rejuvenated over a length of 3 cm towards the gas inlet 2.2 for the reaction gases 2.3. From the upper end of the lower region, the wall 2.6 ran vertically upwards over a length of 18 cm, so that in this region the reaction space 2.1 had a constant cross section of 13 cm. At the upper end of this range, the cross-section of the reaction space widened over a length of 4 cm to a maximum of 16 cm. This widened region of the reaction space served as separation zone 2.13, in which the majority of the gas stream 2.9 entrained, loaded with catalytically active nanoparticles 2.10.2, meso and / or macroporous particles 2.11.1 were decoupled from the gas stream 2.9 and back into the fluidized bed 2.11 fell back. In this area was also the gas outlet 2.4 for the exhaust 2.5. The gas outlet 2.4 was connected to a cyclone 15 made of stainless steel, wherein the discharged meso and / or macroporous particles 2.1 1.1 separated from the gas phase and fed via the recirculation device 15.1 the lower portion of the reaction chamber 2.1 above the igniter 8, 8.1 again the fluidized bed 2.11 were. The exhaust gases 15.3 of the cyclone 15 were discharged via the exhaust pipe 15.2.

The meso and / or macroporous particles of alumina 2.11.1 had a narrow monomodal distribution and a mean particle size of 500 μm determined by laser scattering and an average pore size of 100 nm. They were hydrophobicized with TEOOS, loaded with Pd @ Ce02 nanoparticles 2.10.2, and then calcined.

Below the fluidized bed 2.11 and the end of the thermal energy absorbing portion 3.3 of the heat pipe 3, the ignition device 8 was arranged with heated, gas-permeable catalyst sheets 2.7. The gas-permeable catalyst plates 2.7 also served as a gas distributor. The igniter 8 was just like that long operated until the flameless catalytic oxidation of natural gas by air in the fluidized bed 2.11 of the reaction chamber 2.1 was self-sustaining.

In the reaction space 2.1, the thermal energy absorbing area 3.3 of the closed heat pipe 3 was arranged centrally. The thermal energy absorbing area 3.3 was 18 cm long. The closed heat pipe 3 had a wall 3.2 of 3 mm and a circular cross-section of 3 cm. Inside was a braid of copper fibers as a wick for the working liquid water (not reproduced).

At the upper end of the fluidized bed reactor 2, the 3 cm long connection area 3.1 between the thermal energy absorbing area 3.3 and the 10 cm long, the thermal energy emitting area 3.4 followed. The thermal energy donating region 3.4 was surrounded by TEE (TEE 4a and 4b are shown). Between their hot sides 4a.1 and 4b.1 and the wall 3.2 were electrically insulating, thermally conductive layers (not shown). The cold sides 4a.2 and 4b.2 of the TEEs 4a and 4b were connected to the heat sinks 5a and 5b via electrically insulating thermally conductive layers 12 (not shown).

From the upper side ends of the TEEs 4a and 4b, electric wires led through the insulating material 7 made of glass foam to the electric terminals 6a and 6b. Glass foam 7 was also located between the upper end of the fluidized-bed reactor 2 and the TEEs 4a and 4b, as a result of which the connection region 3.1 was also thermally insulated. Otherwise, the entire fluidized bed reactor 2 was surrounded by glass foam 7, with only the inlet device 2.2 and the outlet device 2.4 were not isolated. The flameless catalytic oxidation of natural gas by means of air was also excellently catalyzed by the Pd @ CeO 2 nanoparticles 2.10.2 in the device 1 according to the invention as shown in FIG. 12, so that the reaction was complete even at 250 ° C.

FIG. 3 illustrates the design and operating principle of yet another preferred embodiment of the device 1 according to the invention on the basis of a detail from its longitudinal section The embodiment of the device 1 according to the invention according to FIG. 13 had the same closed heat pipe 3 with the wall 3.2, the thermal energy emitting area 3.4 and the thermal energy absorbing area 3.3 like the device 1 according to the invention as shown in FIG 4, the heat sinks 5 and the glass foam 7 are arranged in this area as well as in the device 1 according to the invention according to FIG. 12.

The heat source 2 was a total of 25 cm long and had a circular section of 15 cm over a distance of 21 cm. Its wall 2.6 was made of stainless steel and was 5 mm thick. In its lower region, the wall 2.6 tapered over a distance of 3 cm to the inlet device 2.2 made of stainless steel for the reaction gas 2.3 out. The exhaust device 2.4 made of stainless steel for the exhaust gases 2.5 was located at the horizontal upper end of the wall 2.6.

The thermal energy absorbing region 3.3 of the closed heat pipe 3 was arranged centrally in the reaction space 2.1 of the heat source 2. The free reaction space 2.1 was filled over a distance of 20 cm with the tubular, macroporous sintered body 2.14 made of TEOOS hydrophobicized and sintered alumina. The sintered body 2.14 had pores 2.14.1 with a mean pore size of 400 nm, into which Pd @ Ce02 nanoparticles 2.10.2 had been incorporated. Above the upper end of the sintered body 2.14, the reaction space 2.1 remained free over a distance of 1 cm in order to facilitate the discharge of the exhaust gases 2.5. Below the end of the closed heat pipe 3, a disk-shaped macroporous sintered body 2.14.2 of the same composition was arranged. It had a circular cross-section of 9.8 cm and a thickness of 1 cm and was connected to the igniter 8, with which the disk-shaped, macroporous sintered body 2.14.2 until the onset of self-sustaining flameless catalytic oxidation of natural gas by air the ignition temperature was heated.

In the region of the wall 2.6 tapering towards the inlet device 2.2, a gas-permeable stainless steel sheet 2.14.3 was still arranged as a gas distributor.

The flameless catalytic oxidation of natural gas by means of air was also excellently catalyzed by the Pd @ CeO 2 nanoparticles 2.10.2 in the device 1 according to the invention as shown in FIG. 13, so that the reaction was complete even at 250 ° C. The inventive device 1 according to the figure 13 proved in practice to be particularly robust, mechanically stable, storable, transportable and easy and safe in operation and had a particularly long service life.

Claims

claims

1. Device (1) for direct conversion of thermal energy into electrical energy, comprising as a heat source at least one device (2) for flameless catalytic oxidation of hydrocarbons having at least one reaction space (2.1), at least one inlet device (2.2) for a gas or a Gas mixture (2.3), at least one outlet device (2.4) for the exhaust gases (2.5) and a wall (2.6), as a transmitter thermal energy at least one heat pipe (3) with a connection region (3.1), a fluid-tight wall (3.2), a thermal Energy receiving area (3.3) and a thermal energy emitting area (3.4), at least one thermoelectric element (4) with electrical connections (6) and at least one heat sink (5), wherein

- The at least one heat pipe (3) with its thermal energy absorbing portion (3.3) in heat-conducting contact with the at least one device (2) and with its thermal energy emitting area (3.4) in heat-conducting, electrically insulating contact with the hot side (4.1 ) of the at least one thermoelectric element (4) and wherein the hot side (4.1) opposite, cold side (4.2) of the at least one thermoelectric element (4) in thermally conductive, electrically insulating contact with the at least one heat sink (5) ,

2. Device (1) according to claim 1, characterized in that the thermal energy emitting area (3.4) of the at least one heat pipe (3) in the hot side (4.1) of the at least one thermoelectric I Element (4) has an opening (3.6) through the wall (3.2), so that the interior of the at least one heat pipe (3) is in direct contact with the hot side (4.1).

3. Device (1) according to claim 2, characterized in that the hot side (4.1) d the nut it at least one thermoelectric element (4) in the region of the opening (3.6) through the wall (3.2) of the thermal energy emitting area ( 3.4) is covered by an electrically insulating, thermally conductive layer (11).

4. Device (1) according to claim 3, characterized in that the electrically insulating, thermally conductive layer (11) has a structured surface (11.1).

Device (1) according to one of claims 1 to 4, characterized in that the cold side (4.2) of the at least one thermoelectric element (4) via an electrically insulating, thermally conductive layer (12) is connected to the heat sink (5).

Device (1) according to one of claims 1 to 5, characterized in that the device (2) for flameless catalytic oxidation of hydrocarbons in their reaction space (2.1) at least one catalyst layer (2.10) comprising at least one carrier layer (2.10.1) and at least one type of catalytically active nanoparticles (2.10.2) on at least one gas-permeable catalyst support (2.7), or a fluidized bed (2.11) containing at least one type of meso and / or macroporous particles (2.11.1) containing at least one type catalytically more effective Nanoparticles (2.10.2), or at least one meso and / or macroporous sintered body (2.14) with pores (2.14.1) of an average pore size of 50 to 1000 nm, containing at least one type of catalytically active nanoparticles (2.10.2), contains.

Device (1) according to one of claims 1 to 6, characterized in that the catalytically active nanoparticles (2.10.2) at least one oxide selected from the group consisting of scandium oxide, yttrium oxide, lanthanum oxide, titanium dioxide, zirconium dioxide, hafnium dioxide, vanadium oxide, Niobium oxide, tantalum oxide, manganese oxide, iron oxide, chromium oxide, molybdenum oxide, tungsten oxide, zinc oxide, oxides of lanthanides, oxides of actinides, magnesium oxide, calcium oxide, strontium oxide, barium oxide, aluminum oxide, gallium oxide, indium oxide, silicon dioxide, germanium oxide, tin oxide, antimony oxide, bismuth oxide, zeolites, Spinels and mixed oxides of at least two of said oxides, and at least one metal selected from the group consisting of vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, osmium, cobalt, rhodium , Iridium, nickel, palladium, platinum, copper, silver and gold.

Device (1) according to claim 7, characterized in that the surface of the oxides is hydrophobic.

Device (1) according to claim 6, characterized in that the meso and / or macroporous particles (2.11.1) are composed of silicon dioxide and / or aluminum oxide.

Device (1) according to one of claims 1 to 9, characterized in that the hydrocarbons in the reaction gas (2.3) from the group consisting of methane, ethane, propane, butane, isobutane, pentane and its isomers, hexane and its isomers, Cyclopentane and cyclohexane.

Device (1) according to one of claims 1 to 9, characterized in that the flameless catalytic oxidation in the reaction space (2.1) at 50 to 400 ° C is feasible. Method for the direct conversion of thermal energy into electrical energy, in which the thermal energy supplied by at least one heat source (2) is transported by means of at least one heat pipe (3) to the hot side (4.1) of at least one thermoelectric element (4) supplied thermal energy in the at least one thermoelectric element (4) an electrical voltage is generated and the remaining supplied thermal energy from the hot side (4.1) opposite cold side (4.2) of the at least one thermoelectric element (4) of a heat sink (5) is supplied, characterized in that one uses for this purpose a device (1) according to one of claims 1 to 11.