DE102013022190A1 - Device and method for direct conversion of thermal energy into electrical energy - Google Patents

Abstract

Device (1) according to FIG. 1 for the direct conversion of thermal energy into electrical energy, comprising - a device (2) for the flameless catalytic oxidation of hydrocarbons, - a heat pipe (3), - a thermoelectric element (4) connected to an electrical connection (6) ) and - a heat sink (5), wherein - the heat pipe (3) with its thermal energy absorbing portion (3.3) in thermally conductive, electrically insulating contact with the device (2) and with its thermal energy emitting region (3.4) in heat conducting, electrically insulated contact with the hot side (4.1) of the thermoelectric element (4) and wherein - the hot side (4.1) opposite cold side (4.2) of the thermoelectric element (4) in thermally conductive, electrically insulating contact with the heat sink (5 ) stands; and methods for directly generating electrical energy from thermal energy.

Description

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 the direct conversion of thermal energy into electrical energy using a temperature gradient (Seebeck effect) as well as suitable materials for the production of such devices are e.g. B. from the American patent US 5,610,366 A , the American patent application US 2010/02299911 A1, the international patent application WO 97/44993 A1 , the 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 Elsner 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 / TEE / heat absorbing device configuration", on the other hand, allows a variety of applications because of the large number of heat sources on the one hand and heat absorbing devices, particularly as self-sufficient, electrical distribution-independent sources of electrical energy.

• – durch die Solarthermie erhitzte photovoltaische Zellen oder Solarzellen; im Allgemeinen weisen die betreffenden Vorrichtungen die Konfiguration ”Solarzelle/elektrisch isolierende, wärmeleitende Schicht/TEE/wärmeabsorbierende Vorrichtung” auf (vgl. die amerikanischen Patentanmeldungen US 2011/0048488 A1 und US 2011/0048489 A1 oder die amerikanischen Patentschriften US 7,875,795 B2 , US 4,106,952 und US 3,956,017 ),
• – die Abwärme von Motorblöcken, Auspuffanlagen, Rauchrohren, Abgaskaminen, Öfen oder Behältern mit Materialien, die bei Phasenumwandlungen thermische Energie liefern (vgl. die deutsche Patentanmeldung DE 199 46 806 A1 , die internationalen Patentanmeldungen WO 99/36735 und WO 01/80325 A1 , die amerikanische Patentanmeldung US 2006/0266404 A1 oder die amerikanischen Patente US 6,232,545 B1 , US 6,624,349 B1 , US 6,527,548 B1 und US 6,053,163 B1 ), oder
• – Sonnenkollektoren, insbesondere Flachkollektoren (vgl. die amerikanische Patentanmeldung US2010/0300504 A1, die europäische Patentanmeldung EP 2 239 187 A1 oder die deutschen Patentanmeldung DE 10 208 009 979 A1 , DE 36 19 127 A1 und DE 37 04 559 A1 )

in Betracht.In this case come as a source of thermal energy as different devices such

• - photovoltaic cells or solar cells heated by solar thermal energy; in general, the subject devices have the configuration "solar cell / electrically insulating, heat-conducting 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, exhaust systems, flue pipes, flue gas, furnaces or containers with materials that provide thermal energy during phase transformations (see the German patent application DE 199 46 806 A1 , the international patent applications WO 99/36735 and WO 01/80325 A1 , US patent application US 2006/0266404 A1 or the US patents US 6,232,545 B1 . US 6,624,349 B1 . US 6,527,548 B1 and US 6,053,163 B1 ), or
• - Solar panels, 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, in the American patent US 5,968,456 proposed a catalytic converter that uses the energy of the exothermic reactions of engine exhaust gas constituents 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.

In the German Offenlegungsschrift DE 10 2008 040 849 A1 describes a catalytically active layer for the oxidation of components 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 ≥ 2 nm to ≦ 5 nm.

From the German patent application DE 10 2010 031 502 A1 is a tubular thermoelectric generator, which is flowed through by a fluid out. 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.

This is the thesis of Ewald Maria Sütterlin, >> Catalytic Oxidation for Electricity Generation, Studies on Thermogenerator, Gas Oxidation and Injector Burner <<, Diplomica® Verlag GmbH, ISBN: 978-3-8366-5863-8, 2008 , proposed a catalytic butane diffusion burner as a heat source 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.

From the Japanese patent application JP 2009027876 A is a portable TEE with an integrated catalytic gas burner known. 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 the Japanese patent application JP 2004064853 A Also, a portable TEE is known that includes an integrated catalytic gas burner. The catalyst of the burner is located in the cavity between two parallel plates with TEE. The cavity and the catalyst are permeable to air. The fuel gas is passed through an inlet into the cavity. The air is sucked into the two open ends of the cavity. At the same time serve the two open ends as an outlet for the exhaust gases.

From the Japanese patent application JP 2012105512 A a TEE is known that also includes 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 known. The catalyst used is cerium oxide-supported palladium or platinum.

From the Chinese patent application CN 102000570 A For example, the catalytic oxidation of methylbenzene at 220 to 300 ° C is known. The catalyst used is a honeycomb ceramic made of Pd / CeO.8 ZrO.2O ₂ .

From the Chinese patent application CN 102407129 A For example, 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 yttrium-stabilized zirconium nanoparticles.

From the Taiwanese patent application TW 201221214 A For example, a catalytic process for removing 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 Jaén, JC Hernández Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gámez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ CeO2 Subunits on Functionalized Al2O3", in Science, Vol. 337, pp. 713-717, 2012 , a catalyst for the catalytic oxidation of methane is known, which is composed of palladium nanoparticles, which are coated by ceria nanoparticles, is built (= Pd @ CeO ₂ ). The catalyst particles are bound to hydrophobized alumina surfaces.

From the international patent application WO 2013/145920 A1 Also, catalysts based on palladium coated on an inorganic porous material are known. 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 250 ° C.

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 the equation I:

Equation I

The Carnot efficiency η _c is given by Equation II: Equation II

"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" denotes the so-called figure-of-merit, d. H. the ability of a material to efficiently generate thermoelectric energy. It is defined in Equation XII.

The efficiency is also severely affected by the thermal resistance between the hot TEE electrode and the heat source at the temperature T _HH , and the resistance between the cold TEE electrode and the heat dissipation at the temperature T _CC . For the same thermal resistance R ₁ , the total thermal resistance is given by equation III, where R _TEE = thermal resistance of the TEE.

Equation III

• R _total = 2R ₁ + R _TEE ;

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

Equation IV

• Q = (T _HH - T _CC ) / R _TEE on

Equation V

• Q '= (T _HH - T _CC ) / (2R ₁ + R _TEE ).

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

Equation VI

• ΔT = T _HH - T _CC on

Equation VII

• ΔT '= (T _HH - T _CC ) R _TEE / (R _TEE + 2R ₁ ).

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

Thus for 2R ₁ = 0.25R _TEE the Carnot efficiency is reduced by 21% and for 2R ₁ = 0.5R _TEE even by 43%, at T _CC = 70 ° C, T _HH = 250 ° C.

The thermal resistance R ₁ is set according to equation IX from the transition or contact resistance R _h1 between the TEE and the thermal conductor at one end, the transition or contact resistance R _h2 between the heat conductor and the heat source at the other end and the thermal resistance R _L the heat conductor himself together.

Equation IX

• R ₁ = R _h1 + R _h2 + R _L.

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

Equation X

• R _L = L / k _L A _L.

Common, inexpensive materials with high k _L values are Cu or Al. So that the line resistance R _L remains small enough, the cross section A _{L 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 / h _c A.

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 compound, the h _c value is very large and thus R _{h is} small. R _h can not be reduced by increasing the contact area, because this 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 easily, z. B. 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, d. H. an absorber of solar energy, a middle part with TEE and a rear part with cooling elements. The solar collector can consist of materials as different as metal, cement, concrete, bricks, porcelain, ceramics or plastic. 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. Since at the US 2010/0300504 A1 known solar panels but materials of different thermal expansion coefficients are to be joined so to speak under duress, there is a high risk that the induced by the high temperature differences and the different thermal expansion coefficients mechanical stresses may sooner or later lead to damage to the solar panels, which is a significant disadvantage is.

To remedy the disadvantages associated with the application of pressure is disclosed in the American patent US 6,232,545 B1 proposed a shingled electrical network assembly comprising a terraced substrate, an insulating film, a metal layer of copper and thermophotovoltaic cells connected to the copper layer. 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 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 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 600 K, ammonia in the temperature range of about 150 to 170 K, mercury in the temperature range of 400 to 800 K or lithium or silver in a temperature range above 1000 K.

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

In addition, devices with TEEs 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 , the American patent US 4,520,305 , the Japanese patent applications JP S5975684 A and JP S60125181 A or the 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 are no longer to have the disadvantages of the prior art, but they are 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

• – als Wärmequelle mindestens eine Vorrichtung (2) zur flammenlosen katalytischen Oxidation von Kohlenwasserstoffen mit mindestens einem Reaktionsraum (2.1), mindestens einer Einlassvorrichtung (2.2) für ein Gas oder ein Gasgemisch (2.3), mindestens einer Auslassvorrichtung (2.4) für die Abgase (2.5) und eine Wandung (2.6),
• – als Überträger thermischer Energie mindestens ein Wärmerohr (3) mit einem Verbindungsbereich (3.1), einer fluiddichten Wand (3.2), einem thermische Energie aufnehmenden Bereich (3.3) und einem thermische Energie abgebenden Bereich (3.4),
• – mindestens ein thermoelektrisches Element (4) mit elektrischen Anschlüssen (6) und
• – mindestens eine Wärmesenke (5), wobei
• – das mindestens eine Wärmerohr (3) mit seinem thermische Energie aufnehmenden Bereich (3.3) in wärmeleitendem Kontakt mit der mindestens einen Vorrichtung (2) und mit seinem thermische Energie abgebenden Bereich (3.4) in wärmeleitendem, elektrisch isolierendem Kontakt mit der heißen Seite (4.1) des mindestens einen thermoelektrischen Elements (4) steht und wobei
• – die der heißen Seite (4.1) gegenüber liegende, kalte Seite (4.2) des mindestens einen thermoelektrischen Elements (4) in wärmeleitendem, elektrisch isolierendem Kontakt mit der mindestens einen Wärmesenke (5) steht.

Accordingly, the new device ( 1 ) for direct generation of electrical energy from thermal energy, comprising

• As a heat source, at least one device ( 2 ) for the 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 of thermal energy at least one heat pipe ( 3 ) with a connection area ( 3.1 ), a fluid-tight wall ( 3.2 ), a thermal energy absorbing 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 ), in which
• - the at least one heat pipe ( 3 ) with its thermal energy absorbing 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 where
• - the hot side ( 4.1 ) opposite, cold side ( 4.2 ) of the at least one thermoelectric element ( 4 ) in heat-conducting, 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 process for the direct conversion of thermal energy into electrical energy has been found, in which the at least one heat source ( 2 ) supplied thermal energy by means of at least one heat pipe ( 3 ) to the hot side ( 4.1 ) 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 ), characterized in that one uses the device according to the invention for this purpose.

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 prior art, it was surprising and unforeseeable for the skilled person that the object underlying the present invention could be achieved by means of the device according to the invention 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 had the disadvantages of the prior art, but a particularly efficient transport of the thermal energy from the heat source to a thermoelectric element (TEE) and the efficient dissipation of the remaining supplied thermal Allowed energy 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 contact 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, high demands had to be placed on the quality and planarity of the contact surfaces in question, because otherwise, in particular, the temperature drop between the source of the thermal Energy and the hot side of the TEE was too high and thus 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 their components could be combined with each other 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.

For the purposes of the present invention, oxidation is to be understood as meaning the reaction of a reducing agent with oxygen. 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 + 2O ₂ → CO ₂ + 2H ₂ O

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 ceria, especially ceria, oxides of actinides, magnesia, calcia, strontia, baria, alumina, gallia, indium, silica, germania, tin oxide, antimony oxide, bismuth oxide, zeolites, spinels, mixed oxides of at least two of said oxides, and hydroxyapatite , 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.

Very particularly preferred are those in the Article by M. Cargnello, JJ Delgado Jaén, JC Hernández Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gámez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ CeO2 Subunits on Functionalized Al2O3", in Science, Vol. 337, pp. 713-717, 2012 , Catalytically active nanoparticles described, which are composed of palladium nanoparticles, which are coated by ceria nanoparticles, are built (= 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 higher temperatures that they are not replaced by the reaction gases flowing 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-non-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 are selected.

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 the selection of 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. Accordingly, the openings may for example be triangular, quadrangular, pentagonal, hexagonal, circular, elliptical, rectilinear or curved slot-shaped, zigzag or meandering or in the Japanese patent application JP 2009027876 A in the 3 (a) - 3 (c) . 4 (a0) - 4 (a2) . 4 (b0) - 4 (b2) and 9 (a) - 9 (f) have revealed forms.

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.

The meso and / or macroporous particles are preferably composed of the above-described oxides, in particular aluminum oxide and / or silicon dioxide, and / or hydroxyapatite. 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. The diameter is preferably in the range from 0.1 to 1000 μm, preferably 0.2 to 800 μm and in particular 0.3 to 600 μm.

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 the Technology Licensing Office (TLB) of the 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 advantages and >> Macroporous ceramics and polymer foams: Examples: Al2O3 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 the Technology Licensing Office (TLB) of the 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 advantages << and >> Macroporous ceramics and polymer foams: Examples: Al2O3 ceramic and PVC polymer foam << disclosed methods are produced. Furthermore, meso and / or macroporous sintered bodies from 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 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 space containing a fluidized bed, widens and serves as a separation zone in which mesoporous 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 place to another, i. H. 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 600 K, ammonia in the temperature range of about 150 to 170 K, mercury in the temperature range of 400 up to 800 K or lithium or silver in a temperature range above 1000 K. 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, have to be chemically stable, mechanically and thermally stable, as well as resistant to deformation, both in the temperature range prescribed by the heat source and in terms of fluid and gas tightness both to the working fluid and to the external atmosphere. 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 thermally and / or curable with actinic radiation such as UV radiation or electron radiation, 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, z. As copper wire mesh or electrically non-conductive wire mesh and fiber bundles, z. B. ceramic, glass or high temperature resistant plastics, are generated in the interior of the heat pipe. Furthermore, the wicking effect may also be due to surface structures of elevations and depressions such. As grooves, columns, balls or cups on the inner wall of the heat pipe are generated.

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-conductive contact with the heat source, d. H. 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. H. with the thermal energy absorbing portion, and the heat source by solder contacts, welding contacts, flange contacts, electrically and thermally conductive, metal particles containing adhesive layers, screw, plug and terminal contacts, in which the end of the heat pipe, d. H. 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, for example, by means of thermally conductive ceramic layers, thermally conductive plastic layers, for example based on polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), poly (trifluorochloroethylene) (KEL-F ^® ), 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 reduced by the use of thermal paste, eg. As thermal pastes based on silicones, further improved.

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 kind are wood, and polymers such Polytertrafluorethylen (PDFE), polyvinylidene fluoride (PVDF), poly (trifluorochloroethylene) (KEL-F ^®), Poysiloxanen, polyether sulfones, polyether ketones 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, thermally conductive 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 liquid to the other end of the heat pipe, d. H. 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 contact device further comprises a fluid and gas tight, adhesive, electrically insulating seal between the wall of the heat pipe and the hot side of the TEE. This seal need not be heat-conducting, but may be electrically conductive as long as it does not make electrical contact with the wall of the heat pipe and the hot side of the TEE. The easiest way to accomplish this is that the surface of the electrically insulating, thermally conductive layer described above is designed to be slightly larger than the hot side of the TEE, so that the surface protrudes all over the surface of the hot side and flush abuts the seal , An example of a suitable, gas- and fluid-tight, adherent, electrically conductive seal are 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, one speaks of a "thermopile". At the electrically positive and electrically negative end of the TEE or the thermopile electrical connections are attached, which can be connected to a device which is operated with the recovered power.

• – Niedertemperaturbereich, d. h. Temperaturen bis zu 250°C,
• – Mitteltemperaturbereich, d. h. Temperaturen bis zu 600°C und
• – Hochtemperaturbereich, d. h. Temperaturen bis zu 1000°C.

In general, there are three temperature ranges when operating TEE

• - Low temperature range, ie temperatures up to 250 ° C,
• - Medium temperature range, ie temperatures up to 600 ° C and
• - High temperature range, ie 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 disclosed in US patent application US 2010/0229911 A1, page 1, paragraphs [0003] to [0011], or in the American patent US 5,610,366 , Column 2, page 27, to column 3, page 32, known.

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 the US patent US 5,610,366 , the American patent application US 2010/0229911 A1, the international patent application WO 97/44993 A1 , the 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 Elsner and JC Bass , described.

Preferably thermoelectric modules are used in "eggcrate" configuration (egg-box configuration), as described for example in the international patent application WO 97/44993 , Page 2, last paragraph, to page 15, last paragraph, in conjunction with the 1A to 14 and 27 to be discribed. 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 of the supplied thermal energy is transmitted 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 surface heating systems which can be installed under walls, ceilings or floors in the interior and exterior 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 transported by means of at least one heat pipe to the hot side of at least one TEE, wherein an electric voltage is generated in the TEE. 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.

In the following, the device according to the invention 1 based on 1 to 13 exemplified. Both 1 to 13 they 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.

The 1 shows the construction and operation principle of a device according to the invention 1 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 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.

The 2 shows the construction and action principle of another device according to the invention 1 wherein the flameless catalytic oxidation device 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 in electrically insulating, thermally conductive contact with at least two further heat pipes which supply the remaining heat each lead at least one heat sink.

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

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

The 5 shows a section along the line BB through the device according to the invention 1 according to the 3 wherein the thermal energy absorbing portion of the heat pipe is in thermal contact with at least one gas permeable catalyst carrier in the reaction space of the apparatus for flameless catalytic oxidation of hydrocarbons.

The 6 shows an enlarged section of the longitudinal section through the device according to the invention 1 according to the 3 In the field of apparatus for flameless catalytic oxidation of hydrocarbons having at least three mutually parallel, gas-permeable catalyst carriers surrounding the thermal energy receiving portion of the heat pipe concentric.

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

The 8th shows a further enlarged section of a portion of the gas-permeable catalyst support according to the 7 with the catalytic surface.

The 9 shows an enlarged section of the mounting portion of the heat pipe of the device according to the invention 1 according to the 3 ,

The 10 shows a further enlarged section of the mounting portion of the heat pipe of the device according to the invention 1 according to the 3 ,

The 11 shows the side view of the heat pipe of the device according to the invention 1 according to the 3 in the direction of the mounting flanges and the opening.

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

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

LIST OF REFERENCE NUMBERS

1

Device according to the invention for direct conversion of thermal energy into electrical energy

2

Apparatus for the flameless catalytic oxidation of hydrocarbons

2.1

reaction chamber

2.2

gas inlet

2.3

reaction gases

2.4

gas outlet

2.5

exhaust

2.6

Wall of the reaction space

2.7

gas permeable catalyst support

2.8

Gas passage

2.9

through flowing gases

2.10

catalyst layer

2.10.1

backing

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

pore

2.14.2

disc-shaped, macroporous sintered body

2.14.3

gas distributor

3

heat pipe

3a, 3b

heat pipes

3.1

connecting area

3a.1, 3b.1

connecting 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

8th

detonator

8.1

heated catalyst sheets 2.7

9

flowing fluid

10

electrically conductive seal

10a, 10b

electrically conductive seals

10c, 10d

electrically conductive seals

11

electrically insulating, thermally conductive layer

11a, 11b

electrically insulating, thermally conductive layers

11c, 11d

electrically insulating, thermally conductive layers

11.1

structured surface

11a.1, 11b.1

structured surfaces

11c.1, 11d.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 14

13a, 13b

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

13c, 13d

angle-shaped, electrically and thermally insulating connecting parts 13 between two electrically and thermally insulating anchoring parts 13

14

screw

14.1

screw head

14.2

washer

14.3

thread

14.4

Senkschraubenkopf

14.5

Through hole with internal thread

15

cyclone

15.1

Recirculation device

15.2

exhaust pipe

15.3

exhaust

A-A

first section line through the device according to the invention 1

B-B

second section line through the device according to the invention 1

L

Longitudinal axis of the device according to the invention 1

The 1 illustrates the general construction and operating principle based on a longitudinal section through the device according to the invention 1 ,

About the inlet device 2.2 became the reaction gases 2.3 , in the present case air and natural gas, the reaction space 2.1 the heat source 2 fed. 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 from the wall 2.6 enclosed gas- and fluid-tight. In the reaction room 2.1 the natural gas was oxidized completely flamelessly at 250 ° C by means of atmospheric oxygen on a catalyst. The exhaust gases 2.5 the oxidation, in this case carbon dioxide, water and unused air, were via the outlet device 2.4 from the reaction space 2.1 directed.

The area 3.3 of the heat pipe 3 that from the heat source 2 supplied thermal energy, projected into the reaction space 2.1 into it. The heat pipe 3 was from the gas and fluid-tight wall 3.2 completely enclosed. By the absorbed thermal energy became the working liquid of the heat pipe 3 , in the present case water, evaporated and over the connecting area 3.1 the thermal energy emitting area 3.4 fed. There the working liquid condensed on the hot sides 4a.1 and 4b.1 the two TEE 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 and thereby generated in the TEE 4a and 4b a voltage applied to the two electrical connections 6a and 6b could be tapped. The remaining thermal energy was then from the cold sides 4a.2 and 4b.2 the two heat sinks 5a and 5b fed.

The 2 illustrates the construction and operation principle of a preferred embodiment with reference to a longitudinal section through the device according to the invention 1 ,

In the device according to the invention 1 according to the 2 dismissed the device 2 for flameless catalytic oxidation of methane also an inlet device 2.2 made of stainless steel for air and natural gas as reaction gases 2.3 on. In the wall 2.6 Stainless steel enclosed reaction space 2.1 the natural gas was catalytically oxidized completely flameless at 250 ° C by the atmospheric oxygen. The exhaust gases were via the outlet device 2.4 made of stainless steel from the reaction chamber 2.1 derived.

The from the heat source 2 supplied thermal energy was from the thermal energy absorbing area 3.3 of the heat pipe 3 added. The wall 3.2 of the heat pipe 3 consisted 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 at 250 ° C.

The absorbed thermal energy was over the bent at an angle of 90 ° connection area 3.1 by the working fluid to the thermal energy emitting area 3.4 fed. There the water condensed on the two hot sides 4a.1 and 4b.1 the two TEE 4a and 4b ,

As TEE 4a and 4b were in the embodiment of the device according to the invention 1 according to the 2 two thermopiles made of TEE in "eggcrate" configuration (egg-box configuration) used, as for example in the international patent application WO 97/44993 , Page 2, last paragraph, to page 15, last paragraph, in conjunction with the 1A to 14 and 27 to be discribed. In particular, the Hi-Z 20 modules, Hi-Z Technology, Inc., USA, have been incorporated into the devices of the invention 1 used.

Both thermopiles 4a and 4b had electrical connections 6a and 6b on.

Your cold side 4a.2 and 4b.2 were each of an electrically insulating, thermally conductive layer 11a and 11b covered by aluminum nitride. The layers 11a and 11b formed the contact surfaces with the remaining thermal energy absorbing areas 3a.3 and 3b.3 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 on.

The absorbed residual thermal energy was transferred over the two transition areas 3a.1 and 3b.1 to the thermal energy absorbing areas 3a.4 and 3b.4 directed. These were in thermal contact with the two heat sinks 5a and 5b ,

The heat sinks 5a and 5b consisted of solid aluminum blocks containing channels for heat absorbing fluids, in this case dem. water, (not shown).

The entire device according to the invention 1 according to the 2 was up to the two heat sinks of a heat-insulating material 7 envelops. As a heat-insulating material 7 Glass foam was used.

With reference to the embodiment according to the 2 could be shown that it is the device according to the invention 1 in a particularly advantageous manner allowed to arrange the essential components spatially arbitrary, without the function of the device according to the invention 1 to impair.

The 3 illustrates the design and operation principle of another preferred embodiment of the device according to the invention 1 by its longitudinal section along its longitudinal axis L.

The device 1 according to the 3 had a particularly advantageous compact design. Air and natural gas were used as reaction gases 2.3 via the inlet device 2.2 made of stainless steel in the reaction chamber 2.1 the device 2 for flameless catalytic oxidation. The reaction space 2.1 was from a cylindrical wall 2.6 completely enclosed gas-tight and fluid-tight from 4 mm thick stainless steel. The exhaust gases 2.5 were over the outlet device 2.4 from the reaction space 2.1 directed. The diameter of the reaction space 2.1 was consistently 10 cm, its height 15 cm.

The reaction space contained a plurality of gas-permeable catalyst supports arranged parallel to one another and one above the other 2.7 of an iron-chromium-aluminum alloy in concentric arrangement around the thermal energy absorbing area 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 hole on. They stood to the longitudinal axis L at an angle of 90 °. They were arranged so that their edges neither the wall 3.2 of the heat pipe 3 still the wall 2.6 the heat source 2 touched. The topmost gas-permeable catalyst support 2.7 was below the outlet direction 2.4 arranged so that in the upper area of the reaction space 2.1 an open zone, which was the better derivation of the reaction gases 2.5 allowed.

The catalyst supports 2.7 were held in this arrangement by a linkage (not shown).

In the lower part of the reaction space 2.1 were below the lower end of the heat pipe 3 but above the inlet device 2.2 several gas-permeable catalyst supports 8.1 arranged, which were constructed and arranged substantially like the catalyst support, except that they had no hole in their middle. Instead, they were with a detonator 8th connected, with the help of the catalyst support 8.1 to the ignition temperature for in the reaction space 2.1 incoming reaction gases 2.3 were brought. After starting the flameless catalyzed oxidation of the natural gas, this ran throughout the reaction space 2.1 without the supply of energy from the outside self-sustaining, which is why the ignition device 8th could be switched off.

The catalyst supports 2.7 and 8.1 had narrow slot-shaped gas outlets 2.8 on (see the 5 ). Further details of the catalyst support 2.7 can be found in the 6 to 8th ,

The thermal energy absorbing area 3.3 of the heat pipe 3 was in the reaction room 2.1 centered in the central bores of the gas-permeable catalyst carrier. Above the reaction space 2.1 the connection area closed 3.1 of the heat pipe 3 through which the absorbed thermal energy using the working fluid in the thermal energy emitting area 3.4 was transported. The areas 3.1 and 3.3 together were 20 cm long and had a circular cross section with a diameter of 3 cm. The strength 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 of electrically insulating ceramic fibers (not shown).

To the top of the connection area 3.1 joined the thermal energy emitting area 3.4 of the heat pipe 3 at. The upper, circular opening of the connection area 3.1 was in the middle of the bottom of the thermal energy emitting area 3.4 arranged. 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 top and bottom of the area 3.4 went the wall 3.2 in the circumferential mounting flanges 3a.5 and 3b.5 about (for further details see the 4 . 9 and 10 ). The mounting flanges 3a.5 and 3b.5 were vertical to the horizontal wall 3.2 at the end and at the bottom of the area 3.4 arranged 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 contact with a circumferential, solid, electrically and thermally insulating anchoring part 13 (see the sections: 13a and 13b ) for screws 14 (for further details see the 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 strength of the electrically insulating, thermally conductive layers 12a and 12b , The upper and lower surfaces of the anchoring parts 13a and 13b closed flush with the upper and lower surfaces of the peripheral mounting flanges 3a.5 and 3b.5 off, leaving the opposite ends each 0.5 cm in the openings in the wall 3.2 in rose. 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; on, leaving the wall 3.2 the bottom of the area 3.4 with the wall 3.2 its upper end over four vertical, 10 cm long, angular struts 3.6 (not reproduced, see the 4 ) were interconnected. The four angular struts 3.6 were thus an integral part of the wall 3.2 ,

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

The electrically insulating, thermally conductive layers 11a and 11b indicated on their surfaces the interior of the area 3.4 turned, textured surfaces 11a.1 and 11b.1 made of thermally conductive nanoparticles.

The electrical wires that make up the TEE 4a and 4b with the electrical connections 6a and 6b were joined by the upper anchoring parts 13a and 13b guided.

The cold sides 4a.2 and 4b.2 were with the electrically insulating, thermally conductive layers 12a and 12b covered by aluminum nitride. These were in direct contact with the heat sinks 5a and 5b , These were made of aluminum blocks 5a.1 and 5B.2 , the channels 5a.2 and 5B.2 for circulating water as heat-absorbing fluid.

Except for the heat sinks 5a and 5b were all components of the device according to the invention 1 according to the 3 with glass foam 7 thermally insulated.

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

The 4 illustrates the construction and operation principle of the preferred embodiment of the device according to the invention 1 according to the 3 from the section along the line AA in 3 ,

As described above, the upper end of the connection portion opened 3.1 of the heat pipe 3 to the thermal energy emitting area 3.4 ,

The thermal energy emitting area 3.4 was mainly from the four electrically insulating, thermally conductive layers 11a . 11b . 11c and 11d limited, 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 clinked. The layers 11a . 11b . 11c and 11d carried on their the interior of the area 3.4 facing surface of the structured surfaces 11a.1 . 11b.1 . 11c.1 and 11d.1 ,

The seals 10a . 10b . 10c and 10d were designed so that every seal 10a . 10b . 10c and 10d to the inner surface of the vertical, angular struts and to the edges of two adjacent electrically insulating, thermally conductive layers 11a . 11b . 11c and 11d flush connected.

Along each angle-shaped strut 3A.6 . 3B.6 . 3c.6 and 3d.6 was a massive, angular, thermally and electrically insulating connector 13a . 13b . 13c and 13d between the two anchoring parts 13a and 13b holding the mounting flanges 3a.5 and 3b.5 enclosed, accurately arranged. The connecting parts 13a . 13b . 13c and 13d passed like the two anchoring parts 13a and 13b 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 pins and complementary recesses to increase the mechanical strength of the assembly (not shown).

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

The cold sides 4a.2 . 4b.2 . 4c.2 and 4d.2 were with the electrically insulating, thermally conductive layers 12a . 12b . 12c and 12d covered. They headed the rest of the way through the TEE 4a . 4b . 4c and 4d passed thermal energy into the heat sinks 5a . 5b . 5c and 5d made of solid aluminum blocks 5a.1 . 5b.1 . 5c.1 and 5d.1 passed. 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 through the connecting pipes 5a.3 . 5b.3 . 5c.3 and 5d.3 produced. 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 could be guided in a spiral through the heat sinks. The inlet of the water 5.4 was at the top of one of the heat sinks 5 and the spout of heated water 5.4 at the bottom of the same or another heat sink 5 ,

The 5 illustrates the construction and operation principle of the preferred embodiment of the device according to the invention 1 according to the 3 from the section along the line BB in 3 ,

The thermal energy absorbing area 3.3 of the heat pipe 3 with the wall 3.2 was in the wall 2.6 enclosed reaction space 2.1 the heat source 2 centered and 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 slot-shaped gas passages 2.8 on. The wall 2.6 was from the heat-insulating material 7 surround.

The 6 to 8th illustrate the design and operation principle of the preferred embodiment of the device according to the invention 1 according to the 3 on the basis of enlarged sections of its section along the longitudinal axis L in 3 ,

The 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 streamed, the heat pipe 3 with the wall 3.2 and the thermal energy absorbing area 3.3 ,

The 7 shows an enlarged section of the arrangement according to the 6 with the gas passage 2.8 a gas permeable catalyst support 2.7 , The surface of the catalyst support was with the catalyst layer 2.10 completely covered. The catalyst layer 2.10 consisted of a carrier layer 2.10.1 , which was essentially made of alumina. The surface of the carrier layer 2.10.1 was hydrophobicized with TEOOS and calcined after application of the catalytically active Pd @ CeO ₂ nanoparticles.

The 8th shows the enlarged section of the arrangement according to the 7 with the catalyst layer 2.10 coming from the carrier layer 2.10.1 and the catalytically active nanoparticles 2.10.2 duration. For the nanoparticles 2.10.2 it was Pd @ CeO ₂ according to the Article by M. Cargnello, JJ Delgado Jaén, JC Hernández Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gámez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ CeO2 Subunits on Functionalized Al2O3", in Science, Vol. 337, pp. 713-717, 2012 ,

The flameless catalytic oxidation of natural gas by air was through the Pd @ CeO ₂ nanoparticles 2.10.2 catalyzed so well that the reaction was complete at 250 ° C.

The 9 and 10 illustrate the design and operation principle of the preferred embodiment of the device according to the invention 1 according to the 3 on the basis of enlarged sections of its section along the longitudinal axis L in 3 ,

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

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

The massive, electrically and thermally insulating anchoring part 13 In its lower area, it met the edge of the gasket with a perfect fit 10 and to the hot surface 4.2 towering area of the layer 11 at. At her the heat sink 5 opposite side surface she was with the mounting flange 3.5 the wall 3.2 of the heat pipe 3 connected.

The connection was made with a through hole with internal thread 14.5 guided, a thread 14.3 having screw 14 in the anchoring part 13 screwed, accomplished. In the embodiment of the 9 became a screw 14 with screw head 14.1 and a washer 14.2 used. In the embodiment of the 9 became a screw 14 with a countersunk screw head 14.4 used.

The 11 illustrates the construction and operation principle of the preferred embodiment of the device according to the invention 1 according to the 3 based on the side view of the heat pipe 3

The heat pipe 3 dismissed the wall 3.2 with the thermal energy absorbing area 3.3 and the connection area 3.1 on. The wall 3.2 pointed in the area of the thermal energy emitting area 3.4 in the center a rectangular breakthrough in the dimensions: height: 10 cm; Width: 6 cm; on, the electrically insulating, thermally conductive layer 11 and the circumferential electrically conductive seal 10 recorded. Above and below the breakthrough went the wall 3.2 in the two vertical mounting flanges 3.5 with the punctures 14.5 with internal thread for holding the screws 14 above. To the left and right of the breakthrough were the vertical angled struts 3.6 arranged, which also in the vertical mounting flanges 3.5 went over. The sides of the vertical angular struts belonging to the visible breakthrough 3.6 had a height of 10 cm and a width of 1 cm.

The 12 illustrates the design and operation principle of another preferred embodiment of the device according to the invention 1 on the basis of her longitudinal section

The device according to the invention 1 according to the 12 showed 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 part, the wall rejuvenated 2.6 over a length of 3 cm to the gas inlet 2.2 for the reaction gases 2.3 out. From the upper end of the lower part of the wall ran 2.6 vertically upwards over a length of 18 cm, so that in this area 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 a separation zone 2.13 , wherein most of the gas stream 2.9 entrained, with catalytically active nanoparticles 2.10.2 loaded, meso and / or macroporous particles 2.11.1 from the gas stream 2.9 were decoupled and returned to the fluidized bed 2.11 fell back. In this area was also the gas outlet 2.4 for the exhaust gases 2.5 ,

The gas outlet 2.4 was with a cyclone 15 made of stainless steel, wherein the discharged meso and / or macroporous particles 2.11.1 deposited from the gas phase and via the recirculation device 15.1 the lower part of the reaction space 2.1 above the ignition device 8th . 8.1 again the fluidized bed 2.11 were fed. The exhaust gases 15.3 of the cyclone 15 were over the exhaust pipe 15.2 derived.

The meso and / or macroporous particles 2.11.1 of alumina had a narrow monomodal distribution and a laser particle size average particle size of 500 microns and a mean pore size of 100 nm. They were hydrophobic with TEOOS, with Pd @ CeO ₂ nanoparticles 2.10.2 loaded and then calcined.

Below the fluidized bed 2.11 and the end of the thermal energy absorbing area 3.3 of the heat pipe 3 was the ignition device 8th with heated, gas-permeable catalyst sheets 2.7 arranged. The gas permeable catalyst sheets 2.7 also served as a gas distributor. The ignition device 8th was operated only until the flameless catalytic oxidation of natural gas by air in the fluidized bed 2.11 of the reaction space 2.1 self-sustaining expired.

In the reaction room 2.1 was the thermal energy absorbing area 3.3 of the closed heat pipe 3 arranged in the middle. The thermal energy absorbing area 3.3 was 18 inches 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 closed 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 at.

The thermal energy emitting area 3.4 was surrounded by TEE (reproduced are the TEE 4a and 4b ). Between her hot sides 4a.1 and 4b.1 and the wall 3.2 were electrically insulating, thermally conductive layers 11 (not shown). The cold sides 4a.2 and 4b.2 the tea 4a and 4b were over electrically insulating, thermally conductive layers 12 (not shown) with the heat sinks 5a and 5b connected.

From the upper lateral ends of the TEE 4a and 4b led electrical lines through the insulating material 7 made of glass foam to the electrical connections 6a and 6b ,

Between the upper end of the fluidized bed reactor 2 and the TEE 4a and 4b was also glass foam 7 , which also causes the connection area 3.1 thermally isolated. Otherwise, the entire fluidized bed reactor was 2 of glass foam 7 surrounded, with only the inlet device 2.2 and the outlet device 2.4 were not isolated.

The flameless catalytic oxidation of natural gas by air has also been used in the device according to the invention 1 according to the 12 through the Pd @ CeO ₂ nanoparticles 2.10.2 catalyzed so well that the reaction was complete at 250 ° C.

The 13 illustrates the construction and operation principle of yet another preferred embodiment of the device according to the invention 1 from a section of her longitudinal section

The embodiment of the device according to the invention 1 according to the 13 had the same closed heat pipe 3 with the wall 3.2 to which the thermal energy dispensing area 3.4 and the thermal energy absorbing area 3.3 on how the inventive device 1 according to 12 , Likewise were the TEE 4 , the heat sinks 5 as well as the glass foam 7 arranged in this area as well as in the device according to the invention 1 according to the 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. Your wall 2.6 was made of stainless steel and was 5 mm thick. In its lower part, the wall rejuvenated 2.6 on a distance of 3 cm to the inlet device 2.2 made of stainless steel for the reaction gas 2.3 out. The outlet device 2.4 made of stainless steel for the exhaust gases 2.5 was at the horizontal upper end of the wall 2.6 ,

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

In which is the inlet device 2.2 towards the rejuvenating area of the wall 2.6 was still a gas-permeable stainless steel sheet 2.14.3 arranged as a gas distributor.

The flameless catalytic oxidation of natural gas by air has also been used in the device according to the invention 1 according to the 13 through the Pd @ CeO ₂ nanoparticles 2.10.2 catalyzed so well that the reaction was complete at 250 ° C.

The device according to the invention 1 according to the 13 proved to be particularly robust in practice, mechanically stable, storable, transportable and easy and safe in operation and had a particularly long service life.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5610366 A [0002]
• WO 97/44993 A1 [0002, 0175]
• DE 10112383 A1 [0002, 0175]
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• US 5610366 [0172, 0175]
• WO 97/44993 [0176, 0211]

Cited non-patent literature

• Company publication of Hi-Z Technology Inc., "Use, Application and Testing or Hi-Z Termoelectric Modules", authors: FA Levitt, NB Elsner and JC Bass [0002]
• 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 [0013]
• Article by M. Cargnello, JJ Delgado Jaén, JC Hernández Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gámez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ CeO2 Subunits on Functionalized Al2O3", in Science, Vol. 337, pp. 713-717 , 2012 [0021]
• Article by M. Cargnello, JJ Delgado Jaén, JC Hernández Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gámez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ CeO2 Subunits on Functionalized Al2O3", in Science, Vol. 337, pages 713 to 717, 2012 [0081]
• Publications of the Technology Licensing Office (TLB) of the 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 advantages and >> Macroporous ceramics and polymer foams: Examples: Al2O3 ceramic and PVC polymer foam << [0101]
• Publications of the Technology Licensing Office (TLB) of the 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 advantages << and >> Macroporous ceramics and polymer foams: Examples: Al2O3 ceramic and PVC polymer foam << [0108]
• 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 a heat source for TEE << [ 0108]
• Company publication of Hi-Z Technology Inc., "Use, Application and Testing or Hi-Z Termoelectric Modules", authors: FA Levitt, NB Elsner and JC Bass [0175]
• Article by M. Cargnello, JJ Delgado Jaén, JC Hernández Garrido, K. Bakhmutsky, T. Montini, JJ Calvino Gámez, RJ Gorte and P. Fornasiero, "Exceptional Activity for Methane Combustion over Modular Pd @ CeO2 Subunits on Functionalized Al2O3", in Science, Vol. 337, pages 713 to 717, 2012 [0247]

Claims (12)

Contraption ( 1 ) for the direct conversion of thermal energy into electrical energy, comprising - as a heat source at least one device ( 2 ) for the 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 of thermal energy at least one heat pipe ( 3 ) with a connection area ( 3.1 ), a fluid-tight wall ( 3.2 ), a thermal energy absorbing 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 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 where - the hot side ( 4.1 ) opposite, cold side ( 4.2 ) of the at least one thermoelectric element ( 4 ) in heat-conducting, electrically insulating contact with the at least one heat sink ( 5 ) stands. Contraption ( 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 area of the hot side ( 4.1 ) of the at least one thermoelectric element ( 4 ) a breakthrough ( 3.6 ) through the wall ( 3.2 ), so that the interior of the at least one heat pipe ( 3 ) in direct contact with the hot side ( 4.1 ) stands. Contraption ( 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 area of the breakthrough ( 3.6 ) through the wall ( 3.2 ) of the thermal energy emitting area ( 3.4 ) of an electrically insulating, thermally conductive layer ( 11 ) is covered. Contraption ( 1 ) according to claim 3, characterized in that the electrically insulating, thermally conductive layer ( 11 ) a structured surface ( 11.1 ) having. Contraption ( 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 ) with the heat sink ( 5 ) connected is. Contraption ( 1 ) according to one of claims 1 to 5, characterized in that the device ( 2 ) for the 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 of catalytically active 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. Contraption ( 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. Contraption ( 1 ) according to claim 7, characterized in that the surface of the oxides is hydrophobic. Contraption ( 1 ) according to claim 6, characterized in that the meso and / or macroporous particles ( 2.11.1 ) are constructed of silicon dioxide and / or aluminum oxide. Contraption ( 1 ) according to one of claims 1 to 9, characterized in that the hydrocarbons in the reaction gas ( 2.3 ) are selected from the group consisting of methane, ethane, propane, butane, isobutane, pentane and its isomers, hexane and its isomers, cyclopentane and cyclohexane. Contraption ( 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. Process for the direct conversion of thermal energy into electrical energy, in which the energy from at least one heat source ( 2 ) supplied thermal energy by means of at least one heat pipe ( 3 ) to the hot side ( 4.1 ) 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 ), characterized in that for this purpose a device ( 1 ) according to any one of claims 1 to 11.

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