DE10303486A1 - Extracting electrical energy from automatic thermal degassing of material containing carbon involves using fuel cell module cathode gas and/or process gas produced from cathode gas as vaporization gas - Google Patents

Abstract

The method involves feeding gaseous vaporization products to the anode (20) side of a high-temperature fuel cell module (22) as fuel and oxidation gas to the cathode (26) side of the fuel cell module. The cathode gas of the fuel cell module and/or process gas produced from the cathode gas is or are used as vaporization gas for the automatic thermal vaporization. An independent claim is also included for the following: (a) a system for extracting electrical energy from automatic thermal degassing of material containing carbon.

Description

The invention relates to a method for the generation of electrical energy from autothermal gasification of carbonaceous material, in which gaseous gasification products High-temperature fuel cell module on the anode side as fuel supplied and the high temperature fuel cell module Oxidator gas supplied on the cathode side becomes.

The invention further relates to a Plant for the production of electrical energy from autothermal gasification of carbonaceous material comprising a gasification reactor and a high temperature fuel cell module, which gaseous gasification products can be supplied as fuel on the anode side are and oxidizer gas can be supplied on the cathode side.

about the gasification of carbonaceous material such as biomass, coal, Biogenic waste materials or carbon-containing residues can be used as fuel for high temperature fuel cells Manufacture from regenerative primary energy sources. Because with high temperature fuel cells the problem of carbon monoxide poisoning of the electrolyte does not occur, no CO fine cleaning of the gaseous Fuel performed become; it can then be electrical Electricity from carbonaceous materials with high efficiency produce, the power generation being particularly decentralized.

From WO 02/065564 A2 it is in Relation to allothermal gasification known, residual anode gas in to couple a gasification reactor.

The invention has for its object that the method mentioned at the beginning and the system mentioned at the beginning to improve that a high efficiency regarding of electricity generation.

With the procedure mentioned at the beginning this object is achieved according to the invention solved, that as Gasifying agent for the autothermal gasification cathode gas of the high-temperature fuel cell module and / or process gas produced by means of cathode gas is used.

Cathode gas, which is used in catalytic combustion of the fuel in the high temperature fuel cell module is consumed contains Oxygen and shows the process temperature the fuel cell. For example, the temperature range is for MCFC systems at approx. 650 ° C and in SOFC systems between 750 ° C and 1000 ° C. By using this hot cathode gas as a gasifier for the autothermal gasification in the gasification reactor achieves increased electrical efficiencies, which by 20% and more those lie when air is used directly as a gasifying agent becomes.

By the method according to the invention let yourself thus with the same entry of carbon-containing material higher Gain electrical power or to obtain the same electrical Performance using cathode gas as a gasifying agent can a lower mass of carbonaceous material is used become.

The same applies to process gas, which by means of cathode gas and in particular by means of thermal combustion of residual anode gas and cathode gas. This process gas is located at a high temperature level and contains oxygen since the fuel cell operated in excess air becomes. This allows the process gas ideal as a gasifying agent for the partial oxidation of carbonaceous material in one Gasification reactor serve, in turn to provide the heat for the gasification.

The process according to the invention can be carried out relatively simple Realize wisely. In particular, an electrical power increase can be achieved reach without high temperature heat exchanger or the like must be provided.

Advantageously, as a source for gasifying agents the high temperature fuel cell module used. This can act as a direct source by (not used) cathode gas is branched off and coupled into the gasification reactor is, or by generating process gas by means of cathode gas, which is then coupled into the gasification reactor. (In the latter case then a conversion device in which by combustion of Anode residual gas with cathode gas is the process gas that is produced direct source for represents the gasification agent and the high temperature fuel cell module as the source of the Cathode gas is an indirect source of the gasifying agent.)

It can be provided that the as Gasification agent used cathode gas or process gas air is admixed. This allows increase the oxygen content of the gasification agent. The air comes with it mixed with a gas at a high temperature level so that the resulting Gasifying agent has a high oxygen content at a high working temperature having. This in turn can the autothermal gasification of the carbonaceous material to effective Perform wise.

Alternatively, it is also possible if only cathode gas and / or process gas produced by means of cathode gas is used as the gasification agent. Due to the gasification agent being at a high temperature level, ef fectively generate heat for the autothermal gasification of the carbonaceous material, the design effort for carrying out the method being minimized.

In a first embodiment is a partial stream of cathode gas on the output side of a cathode High-temperature fuel cell module branched. During a second partial stream can be fed to a conversion device, um over Thermal combustion of residual anode gas can produce a hot process gas feed this partial stream to a gasification reactor, in turn to this cathode gas to provide as a gasifying agent.

In particular, a partial stream is on Cathode gas coupled into a gasification reactor. This will a hot one Oxidizer gas is provided to partially oxidize the carbonaceous material to effect, in turn, the thermal necessary for gasification To provide energy.

It can be provided that a partial flow Cathode gas branched upstream of a conversion device becomes. This partial flow can be as a gasification partial flow for the partial oxidation of carbonaceous Use material. The further partial flow can be the conversion device respectively, a hot one process gas to generate, whose energy content can in turn be exploited.

In particular, it is provided that residual anode gas and cathode gas are supplied to a conversion device. The residual anode gas is fuel which is in the high temperature fuel cell module has not been burned catalytically. The cathode gas is not used up Oxidizer. The unused fuel can be in the conversion device chemically convert with the cathode gas as an oxidizer and in particular thermally burn to such a hot Process gas too produce.

In a second embodiment it is provided that process gas, which is formed in the conversion device, as a gasifying agent is used. This process gas contains oxygen, because high-temperature fuel cells usually operate in excess of oxygen become. The hot process gas with excess oxygen then use it as a gasifying agent, so that in turn an autothermal Gasification of carbonaceous material in a gasification reactor to be able to.

In particular, it becomes a partial flow of process gas, which is formed in the conversion device. This partial flow can be in couple a gasification reactor. Another partial flow of process gas can be dissipate, to use its energy content.

It can be provided that the high-temperature fuel cell module supplied Preheated oxidizer gas to achieve an optimized catalytic combustion.

The procedural effort can be low hold when cathode gas and / or process gas without going through a heat exchanger be coupled into a gasification reactor. Because the cathode gas is from a high-temperature fuel cell at a high temperature level. The process gas comes from a conversion device, so that it is also at a high temperature level. For one Heat exchange process would have to High temperature heat exchanger be provided. This can usually be done at the most realize in several stages, so that corresponding heat losses go hand in hand with a correspondingly complex structure. By the solution of the invention Use of cathode gas and / or process gas as a gasifying agent can such a high-temperature heat exchanger can be dispensed with, but high efficiencies can be achieved and hot process gas can be extracted is.

The above task is at the system mentioned at the outset solved in that at least a branching device is provided, by means of which a Partial stream of cathode gas and / or a partial stream of process gas, which is generated by means of cathode gas, for coupling into the gasification reactor can be branched off as a gasifying agent.

about the branching device or branching devices can be generate a partial flow of cathode gas and / or process gas, which then can be coupled into the gasification reactor as a gasification partial stream is.

The system according to the invention already has described in connection with the inventive method Advantages on.

Further advantageous configurations the system according to the invention were also already in connection with the method according to the invention explained.

In particular, the minimum a branching device of a cathode of the high-temperature fuel cell module based on the flow direction of the oxidizer gas downstream, so as to unused oxidizer gas Use (cathode gas) directly or indirectly as a gasifying agent to be able to.

Cheap it is when the at least one branching device to a Gasification reactor input for Gasifying agent is coupled. It can then be cathode gas and / or process gas couple as a gasifying agent.

In order to be able to increase the oxygen content in the gasification medium which is coupled into the gasification reactor, it is advantageous if a coupling device is provided in a supply line for cathode gas or process gas to the gasification reactor. At this coupling Direction, for example, air or pure oxygen can be added to the cathode gas or process gas, which is coupled into the gasification reactor. The admixture takes place at a high temperature level, so that the gasification agent as a mixture of cathode gas and air or process gas and air is at a high temperature level and at the same time has a high oxygen content.

Alternatively, the high temperature fuel cell module the only source of gasification agent - directly or indirectly - for the gasification agent his. It can be then hot gasifying agent in the with minimal design effort Coupling the gasification reactor to autothermal gasification of the carbonaceous Material.

Cheap it is when a conversion device is provided in which a process gas by means of Anode residual gas and cathode gas can be generated, the cathode gas acts as an oxidizer gas. This allows the gaseous Fuel generated in the gasification reactor and in the high-temperature fuel cell module is not completely catalytic has been implemented completely use a conversion process such as a Afterburner process is carried out around the anode residual gas completely to burn. Hot process gas, its energy content, is then generated is usable.

In a first embodiment is a branching device upstream of the conversion device. It can be then feed a partial stream of cathode gas to the gasification reactor.

In a second embodiment, which is alternative to the first embodiment or with can be combined, is a branching device of the conversion device downstream. It can be then hot Process gas, which was generated in the conversion device, the gasification reactor as a gasifying agent.

In particular, the Process gas branching device can be coupled into the gasification reactor.

The following description of preferred embodiments serves in connection with the drawing to explain the invention in more detail. Show it:

1 a schematic representation of a plant for the production of electrical energy from the autothermal gasification of carbonaceous material with a fuel cell module, as is known from the prior art;

2 a schematic representation of a first embodiment of a system according to the invention and

3 is a schematic representation of a second embodiment of a system according to the invention.

A plant for the generation of electrical energy from the autothermal gasification of carbon-containing material, which is known from the prior art, is in 1 shown schematically and there designated as a whole with 10. This includes a gasification reactor 12 , in which carbonaceous material can be gasified. This carbon-containing material can be, for example, biomass, coal, biogenic waste materials or carbon-containing residues or mixtures of the starting materials mentioned.

The carbonaceous material is in the gasification reactor 12 gasified by oxygen; the oxygen acts as a gasifying agent and causes an autothermal gasification of the carbonaceous material. With autothermal gasification, the energy for the gasification is in the gasification reactor 12 generated by partial combustion of the carbonaceous material. In the case of allothermal gasification, which is not the subject of this application, the energy is introduced indirectly into the gasification reactor through a heat exchanger.

In autothermal gasification, the oxygen is introduced in particular as atmospheric oxygen. The gasification reactor points to this 12 a connection 14 on which air can be injected.

The gasification reactor 12 has another connection 16 on, via the carbonaceous material in the gasification reactor 12 is feasible. Via a decoupling connection 18 solid and / or liquid combustion products and especially ash can be removed.

The gaseous combustion products of the gasification of the carbonaceous material in the gasification reactor 12 are the fuel of an anode 20 of a high temperature fuel cell module 22 fed. The high temperature fuel cell module 22 includes one or more high temperature fuel cells 24 , High-temperature fuel cells operate at a temperature level that is on the order of approximately 650 ° C to 1000 ° C. Between the anode 20 and a cathode 26 is in the high temperature fuel cell 24 a ceramic solid electrolyte 28 arranged. For example, there are fuel cells of the type SOFC (Solid Oxide Fuel Cell) or MCFC (Motten Carbonate Fuel Cell).

The gaseous gasification products of the gasification of the carbonaceous material in the gasification reactor 12 who the anode 20 are used as fuel for the high-temperature fuel cell 24 , This fuel becomes catalytic with the solid electrolyte 28 penetrating ions oxidized, using oxygen as atmospheric oxygen to the cathode 26 is fed. In SOFC systems the ions are oxygen ions, in MCFC systems carbon ions. The cathode 26 is on the input side to an air supply line 30 coupled. The air becomes the cathode before being fed 26 preferably preheated.

Between the gasification reactor 12 and the anode or anodes 20 of the high temperature fuel cell module 22 is a gas cleaning device 32 switched, the input side with the gasification reactor 12 is connected and on the output side to the anode 20 connected is. About this gas cleaning device 32 contaminants such as solid particles and sulfur, chlorine and tar can be removed.

On the high temperature fuel cell module 22 electric power is generated due to the catalytic combustion of the fuel, which is usable.

It is known from the prior art, unburned anode residual gas from a conversion device 33 for chemical conversion of residual anode gas and cathode gas to produce hot process gas. An example of such a conversion device is an afterburner 34 , A first entrance 36 this afterburner 34 is on the anode output side of the high-temperature fuel cell module 22 coupled. A second entrance 38 afterburner 34 is on the cathode output side of the high-temperature fuel cell module 22 coupled.

In the afterburner 34 is the anode residual gas with cathode gas, which is caused by the catalytic combustion in the fuel cell 24 is not used oxidizer gas, burned thermally. At an exit 40 afterburner 34 hot process gas is extracted.

With a biomass input of 1.0 kmol / h, arithmetically results from an 82% fuel conversion and an electrical efficiency of 53% of the high-temperature fuel cell module 22 (an SOFC system is assumed as an example) is based on an input of 12.2 kmol / h of air as a gasifying agent, an electrical output power of the high-temperature fuel cell module 22 of approx. 253 kW. The temperature of the process gas, which is at the output 40 is uncoupled in this example case at approx. 974 ° C.

According to the invention, it is now provided that cathode gas, ie oxidizer gas, after flowing through the cathode 26 , and / or process gas produced by means of cathode gas into the gasification reactor 12 is injected as a gasifying agent.

In a first embodiment according to the invention, which in 2 denoted as a whole by 41, cathode gas becomes the gasification reactor 12 fed. The same components as for the system 1 have the same reference numerals. The supply of fuel to the high temperature fuel cell module 22 and the supply of oxidant gas to this fuel cell module 22 is as described above.

According to the invention is a branching device 42 provided which of the cathode 26 is connected downstream. An entrance 44 this branching device is on the output side with the cathode 26 connected. A first exit 46 the branching device 42 is on the connection 14 of the gasification reactor 12 coupled to the supply of gasification in this. A second exit 48 the branching device 42 is at a first entrance 50 of an afterburner 52 coupled.

Via the branching device 42 can be a partial flow of the cathode gas, that is, a partial flow of the not in the high temperature fuel cell 24 branch off the used oxidant gas and the gasification reactor 12 as a gasifying agent. Another gasifier feed into the gasification reactor 12 is not provided, i.e. no external gasification agent is provided. The only source of gasification agent is through the exit of the cathode 26 educated.

A second entrance 54 afterburner 52 is with the anode 20 connected. The afterburner 52 thus becomes anode residual gas, that is, not in the high temperature fuel cell module 22 Catalytically burned fuel and a partial stream of the cathode gas supplied, which at the second outlet 48 the branching device 22 is dissipated. At an exit 56 afterburner 52 hot process gas can be taken as combustion gas from the combustion of residual anode gas and cathode gas.

In a variant of this embodiment sits in a feed line 53 for that on the junction 42 coupled cathode gas to the gasification reactor 12 a coupling device 55 , through which air can be mixed into the cathode gas flow. As a result, the oxygen content of the gasification agent can be increased, the admixing taking place at a high temperature level.

The method according to the invention for obtaining electrical energy from the autothermal gasification of carbon-containing material functions as follows: The gaseous gasification products are after cleaning in the gas cleaning device 32 as fuel for the anode (s) 20 of the high temperature fuel cell module 22 fed. The cathode side is in the high-temperature fuel cell module 22 Air supplied as an oxidizer gas. In the fuel cell or cells 24 there is a catalytic combustion, electrical energy being obtainable from this catalytic combustion.

Unburned anode residual gas becomes the afterburner 52 fed. Likewise, a partial flow of the cathode gas, which at the second outlet 48 the branching device 42 is tapped, the afterburner 52 supplied in order to burn residual anode gas and cathode gas and to be able to decouple hot process gas.

Another partial flow of the cathode gas is used as a gasification agent in the gasification reactor 12 coupled. This cathode gas as a gasifying agent is hot because the cathode gas is the temperature of the high temperature fuel cell 24 having. The efficiency of the system can be reduced by the partial cathode gas recirculation, that is to say partial use of the cathode gas as a gasifying agent for the gasification of the carbon-containing material 41 compared to that of the plant 10 increase or it can decouple the same electrical power with less use of carbonaceous material. In particular, there is no need to preheat the gasification agent when coupling it into the gasification reactor 12 be provided in order to achieve a high electrical output.

Example calculations showed that with a biomass input of 1.0 kmol / h an electrical output of 293 kW can be achieved if the fuel temperature is 82% in the high-temperature fuel cell 24 and an electrical efficiency of 53% from an introduction of 10.4 kmol / h cathode gas as a gasifying agent. This can be compared with the above value of 253 kW for the system 10 ,

It also has the process gas at the exit 56 afterburner 52 can be removed, a temperature of about 982 ° C, that is, the temperature of the process gas is higher than the process gas at the outlet 40 the plant 10 is removable. In the solution according to the invention, the process gas therefore has a higher energy content.

In a second embodiment of a system according to the invention, which in 3 schematically shown and there as a whole 58 Process gas is referred to as the gasification agent in the gasification reactor 12 coupled.

The same components as for the system 10 are provided with the same reference numerals. The supply of fuel and oxidizer gas is carried out in the same way as with the systems above 10 and 41 described.

To the high-temperature fuel cell module 22 is again the afterburner 34 how related to the facility 10 described, coupled.

The exit 40 afterburner 34 is in the embodiment 58 with an entrance 60 a branching device 62 connected. A first exit 64 this branching device is on the connector 14 of the gasification reactor 12 coupled. A partial stream of process gas can then be branched off by means of the branching device and this process gas as a gasifying agent in the gasification reactor 12 inject.

At a second exit 66 the branching device 62 a second partial flow of process gas can be removed.

According to the invention, it is provided that hot process gas from the afterburner 34 comes into the gasification reactor 12 is injected as a gasifying agent. A partial process gas recirculation thus follows. The afterburner 34 provides the only (direct) source of gasification agent for the gasification reactor 12 to cause an autothermal gasification in it, that is to generate the heat required for the gasification of the carbonaceous material by partial oxidation of a part of this material.

The process gas from the afterburner 34 is very hot. A typical temperature is on the order of 970 ° C. This higher temperature level also results in comparison to the system 10 an increase in performance with respect to the high temperature fuel cell module 22 Removable electrical power or the same electrical power can be achieved with the saving of carbonaceous material.

With a biomass input of 1.0 kmol / h, there is an electrical output of 297 kW, if again an 82% fuel conversion with an electrical efficiency of 53% for the fuel cell 24 and an entry of 11.7 kmol / h of process gas into the gasification reactor 12 Is accepted. The temperature of the process gas at the second outlet 66 the branching device 62 is around 976 ° C.

In a variant of an embodiment sits in a line 65 for process gas in the gasification reactor 12 between the exit 64 the branching device 62 and the connection 14 a coupling device 67 , via which air can be mixed into the process gas stream. As a result, the oxygen content of the gasification agent can be increased, air being coupled in at a high temperature level.

By the inventive solution of the partial recycling of cathode gas - either directly by coupling a partial stream of cathode gas into the gasification reactor 12 or indirectly by coupling in process gas, which was generated with the help of cathode gas, in both cases with possible air admixture - the efficiency of a plant for the production of electrical energy from the autothermal gasification of carbon-containing material can be increased, based on the case where the gasifying agent is external provided.

In particular, a high degree of efficiency can be achieved without the need for gasification agents for coupling into the gasification reactor 12 must be preheated in a separate device. In this case, a high-temperature heat exchanger would have to be provided. Such a high-temperature heat exchanger is technically very complex to implement; in particular, several stages would have to be provided, which in turn increases heat losses and the temperature level of process gas that can be extracted from the system drops.

The solution according to the invention can be used thus increase the efficiency with little effort.

Claims (22)

Process for the production of electrical energy from the autothermal gasification of carbonaceous material, in which gaseous gasification products are fed to a high-temperature fuel cell module as fuel and the high-temperature fuel cell module is supplied with oxidizer gas on the cathode side, characterized in that cathode gas of the high-temperature gas Fuel cell module and / or process gas produced by means of cathode gas is used. A method according to claim 1, characterized in that as Source for Gasification agent the high temperature fuel cell module is used. A method according to claim 1 or 2, characterized in that that the air used as gasifying agent or process gas is admixed. A method according to claim 1 or 2, characterized in that that as Gasifying agents only Cathode gas and / or process gas produced by means of cathode gas are used becomes. Method according to one of the preceding claims, characterized characterized that a Partial flow of cathode gas on the output side of a cathode of the high-temperature fuel cell module is branched off. Method according to one of the preceding claims, characterized characterized that a Partial stream of cathode gas is coupled into a gasification reactor becomes. Method according to one of the preceding claims, characterized characterized that a Partial stream upstream of cathode gas a conversion device is branched off. Method according to one of the preceding claims, characterized characterized that anode residual gas and cathode gas are supplied to a conversion device. A method according to claim 8, characterized in that process gas which is formed in the conversion device, used as a gasifying agent becomes. A method according to claim 8 or 9, characterized in the existence Partial stream of process gas, which is formed in the conversion device, is branched off. A method according to claim 10, characterized in that the Partial flow of process gas is coupled into a gasification reactor. Method according to one of the preceding claims, characterized characterized in that the high temperature fuel cell module supplied oxidizer gas preheated becomes. Method according to one of the preceding claims, characterized characterized that cathode gas and / or process gas without going through a heat exchanger is coupled into a gasification reactor. Plant for the production of electrical energy from the autothermal gasification of carbonaceous material, comprising a gasification reactor ( 12 ) and a high-temperature fuel cell module ( 22 ), to which gaseous gasification products can be supplied as fuel on the anode side and oxidizer gas can be supplied on the cathode side, characterized in that a branching device ( 42 ; 62 ) is provided, by means of which a partial flow of cathode gas and / or a partial flow of process gas, which is generated by means of cathode gas, for coupling as a gasification agent into the gasification reactor ( 12 ) can be branched off. Installation according to claim 14, characterized in that the at least one branching device ( 42 ; 62 ) a cathode ( 26 ) of the high-temperature fuel cell module ( 22 ) downstream of the flow direction of the oxidizer gas. System according to claim 14 or 15, characterized in that the at least one branching device ( 42 ; 62 ) to an entrance ( 14 ) of the gasification reactor ( 12 ) is coupled for gasifying agents. System according to one of claims 14 to 16, characterized in that a coupling device ( 55 ; 67 ) in a supply line ( 53 ; 65 ) for cathode gas or process gas to the gasification reactor ( 12 ) is provided. System according to one of claims 14 to 16, characterized in that the high-temperature fuel cell module ( 22 ) the only source of gasification agent for the gasification reactor ( 12 ) is. Plant according to one of claims 14 to 18, characterized in that a conversion direction ( 33 ) is provided in which a process gas can be generated by means of anode residual gas and cathode gas. Installation according to claim 19, characterized in that a branching device ( 42 ) of the conversion device ( 33 ) is connected upstream. Installation according to claim 19 or 20, characterized in that a branching device ( 62 ) of the conversion device ( 33 ) is connected downstream. Installation according to claim 21, characterized in that by means of the branching device ( 62 ) Process gas in the gasification reactor ( 12 ) can be coupled.