JP2007284287A - Method for starting reforming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively utilize a feedstock gas filled in a reformer and a feedstock gas used to start the reformer, and a like in starting a reforming system. <P>SOLUTION: The problem is solved by a method for starting a reforming system equipped with a steam generation means 30 that generates steam by burning a fuel and a reformer 1 that generates a hydrogen-rich reformate gas from a mixture of a feedstock gas and the steam generated by the steam generation means 30 and feeds the hydrogen-rich reformate gas into a fuel cell 15, wherein the reformer 1 is kept filled with the feedstock gas during the stoppage of operation of the reforming system; a fresh feedstock gas is continuously fed into the reformer 1 at the time of start of the reforming system; the effluent gas from the reformer 1 is fed as a fuel into the steam generation means 30; when steam is generated from the steam generation means 30, the steam is mixed with the feedstock gas and fed into the reformer 1; and after the reformer 1 is raised in its temperature and reaches a temperature at which the reforming operation is possible, the apparatus into which the effluent from the reformer 1 is fed is switched from the steam generation means 30 to the fuel cell 15, whereas the steam generation means 30 is fed with a fuel from another system. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for starting a reforming system that generates a hydrogen-rich reformed gas by steam reforming a raw material gas and supplies the reformed gas to a fuel cell, and more particularly, generates steam by burning fuel. The present invention relates to a method for starting a reforming system provided with a steam generation means.

2. Description of the Related Art Conventionally, there is known a reformer that generates a hydrogen-rich reformed gas by steam reforming a mixture of a source gas and steam (hereinafter referred to as a source-steam mixture) in the presence of a reforming catalyst. The hydrogen-rich reformed gas obtained in the reformer is converted into CO ₂ by reacting residual CO (carbon monoxide) with an oxygen-containing gas in the presence of an oxidation catalyst in a CO selective oxidizer, particularly at low temperatures. For an operating solid polymer electrolyte fuel cell, CO is reduced to several ppm level before being supplied as fuel. As the source gas, hydrocarbons such as methane, aliphatic alcohols such as methanol, ethers such as dimethyl ether, city gas, and the like are used. In such a reformer, the reaction formula of steam reforming when methane is used as a raw material gas can be expressed as CH ₄ + 2H ₂ O → CO ₂ + 4H ₂ , and a preferable reforming reaction temperature is 650 to The range is 750 ° C.

  There are an external heating type and an internal heating type as a system for supplying heat necessary for the reforming reaction of the reformer. The external heating type reformer is provided with a heating unit outside, and a reformed gas is generated by reacting a raw material gas and water vapor with a heat source. The internal heating type reformer is provided with a partial oxidation reaction layer on the supply side (upstream side), and the steam reforming reaction layer disposed on the downstream side using the heat generated in the partial oxidation reaction layer is subjected to a steam reforming reaction. Heating to a temperature is performed, and a steam reforming reaction is performed in the heated steam reforming catalyst layer to generate a hydrogen-rich reformed gas.

The partial oxidation reaction can be represented by CH ₄ + 1/2 · O ₂ → CO + 2H ₂ , and the preferable partial oxidation reaction temperature is in the range of 250 ° C. or higher. For example, Patent Documents 1 and 2 describe a self-oxidation internal heating type reformer as an improvement of the internal heating type reformer. The reformers of Patent Documents 1 and 2 have a double structure including an outer pre-reforming chamber and an inner main reforming chamber communicating with the outer pre-reforming chamber, and the pre-reforming chamber is provided with a reforming catalyst layer. The main reforming chamber is provided with a mixed catalyst layer in which a reforming catalyst and an oxidation catalyst are mixed, a shift catalyst layer, and the like. A supply pipe for supplying oxidized air to the mixed catalyst layer is extended at the central portion of the main reforming chamber, and an air ejection portion including a plurality of nozzles is formed at a portion where the supply pipe extends to the mixed catalyst layer.

Reforming catalyst layer are those of the raw material gas to steam reforming, for example, _NiO-A1 2 _{O 3} or _{NiO-SiO 2 · A1 2 O} 3 Ni -based reforming catalyst and _{WO 2} -SiO 2 · A1 2 such as O ₃ , NiO—WO ₂ , SiO ₂ , A1 ₂ O ₃ or the like is used. The reforming catalyst constituting the mixed catalyst layer is the same as described above, and the oxidation catalyst uniformly dispersed in the reforming catalyst causes the raw material gas in the raw material-steam mixture to oxidize and generate a temperature necessary for the steam reforming reaction. For example, platinum (Pt), rhodium (Rh), ruthenium (Ru), or palladium (Pd) is used. The mixing ratio of the oxidation catalyst to the reforming catalyst is selected in the range of about 1 to 15% according to the type of the raw material gas to be steam reformed. For example, when methane is used as the raw material gas, it is about 5% ± 2%. In the case of methanol, the mixing ratio is about 2% ± 1%. Further, the same oxidation catalyst as that constituting the mixed catalyst is used as the oxidation catalyst provided in the CO selective oxidizer.

  A steam generating means is provided for supplying steam to the reformer. The water vapor generating means burns gaseous fuel or liquid fuel with a burner and heats water with the combustion gas to generate water vapor. On the other hand, anode exhaust gas is discharged from the fuel cell. Since this anode exhaust gas contains a large amount of hydrogen that is not used in the fuel cell, it is desirable to use it as fuel for the steam generating means. Therefore, a circulation pipe for supplying anode exhaust gas from the anode exhaust gas outflow portion of the fuel cell to the water vapor generating means is provided.

  When starting the reforming system, first, a raw material gas is supplied as fuel to the steam generating means, and preparation for supplying steam to the reformer is started. At the same time, the internal temperature of the reformer is raised to the reforming reaction temperature region. In order to raise the temperature of the reformer, a preheater is usually provided. The preheater is filled with an oxidation catalyst, and an electric heater for raising the temperature of the oxidation catalyst at the time of start-up is provided.

  When the electric heater of the preheater is started at the time of starting the reforming system, the internal oxidation catalyst is heated and the temperature is raised. When the raw material gas and start air are supplied to the preheater in a state where the oxidation catalyst is in the oxidation reaction temperature region, the raw material gas reacts with the air by the action of the oxidation catalyst to generate oxidation heat (combustion heat). The high-temperature gas flowing out from the preheater is supplied to the mixed catalyst layer of the reformer, whereby the temperature inside the reformer gradually increases, and when the reforming temperature region is reached, a normal reforming operation is possible, i.e., reforming. Enter the quality driving state.

JP 2004-175582 A JP-A-2005-149860

  In the conventional reforming system, at the time of start-up, first, the raw material gas is supplied as fuel for start from the fuel supply pipe to the steam generating means and burned by the burner to generate steam. When steam is generated from the steam generating means, the steam is supplied to the reformer, and after the reformer reaches the reforming operation state, the reformed gas generated in the reformer is started to be supplied to the fuel cell. Since the anode exhaust gas containing hydrogen is discharged when the fuel cell is operated, the anode exhaust gas is supplied as fuel to the water vapor generating means through a circulation pipe.

  However, the gas flowing out of the reformer before the reformer reaches the operating state is required to be detoxified due to environmental problems. It was necessary to install a new incinerator. Further, in the conventional reforming system start-up method, when the interior of the reformer rises above the carbon deposition temperature (the temperature at which the source gas is carbonized and carbon is precipitated) at the start-up, the existing or remaining source gas may be carbonized. was there. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve such a problem in the conventional method for starting a reformer system, and to provide a new method for starting a reforming system.

  A method for starting a reforming system of the present invention that solves the above-described problem is a hydrogen-rich reformed gas from a mixture of water vapor generating means that burns fuel to generate water vapor, and a raw material gas and water vapor generated by the water vapor generating means. Is a method for starting a reforming system including a reformer that generates and supplies fuel to a fuel cell. Then, when starting the reforming system, new raw material gas is continuously supplied to the reformer, the outflow gas from the reformer is supplied as fuel to the steam generating means, and when steam is generated from the steam generating means, The steam is mixed with the raw material gas and supplied to the reformer. The temperature of the reformer is increased, and when the temperature reaches a state where the reforming operation is possible, supply of the effluent gas from the reformer is performed from the steam generating means. Switching to a fuel cell is performed, and fuel from another system is supplied to the water vapor generating means (claim 1).

  In the start-up method of the reforming system, the supply of steam to the reformer can be performed before the reformer reaches the carbon deposition temperature.

In the above reforming system start-up method, the reformer has a pre-reformer chamber and a main reforming chamber, the pre-reforming chamber is provided with a reforming catalyst layer, and the main reforming chamber is reformed. At least a mixed catalyst layer in which a catalyst and an oxidation catalyst are mixed is provided, a mixture of raw material gas and water vapor is supplied to the pre-reforming chamber, and an outflow gas and oxidizing air from the pre-reforming chamber are supplied to the mixed catalyst layer. The self-oxidation internal heating type configured to supply the reformed gas flowing out from the main reformer to the fuel cell 15 can be used.
Furthermore, during the shutdown of the reforming system, the inside of the preliminary reforming chamber and the main reforming chamber is filled with the raw material gas, and when the reforming system is started, before the reformer reaches the carbon deposition temperature, The source gas filled in the reforming chamber can be replaced with a mixture of the source gas and water vapor (claim 5).

In the start-up method of the reforming system having the self-oxidation internal heating type reformer, the reforming system further includes suction mixing means for mixing the raw material gas and water vapor or start air, an oxidation catalyst, and a heater. A preheater is provided, and the raw material gas or a mixture of the raw material gas and water vapor is supplied to the reformer via the suction mixing means and the preheater,
When starting the reforming system, supply the raw material gas and start air to the preheater, heat the temperature of the mixed catalyst layer with the effluent from the preheater, and mix when the temperature of the mixed catalyst layer reaches the oxidation temperature of the raw material gas. Oxidizing air is supplied to the catalyst layer and mixed with the effluent from the preheater to oxidize at least a part of the raw material gas, and the temperature of the mixed catalyst layer is accelerated by the oxidation heat generated at that time.
When water vapor is generated from the water vapor generating means, the water vapor is supplied to the suction mixing means together with the raw material gas, the supply of the start air to the suction mixing means is stopped, and the raw material gas and water vapor mixture flowing out from the suction mixing means Is supplied to the preliminary reforming chamber of the reformer, and when the reformer reaches the reforming operation state, the supply of the effluent gas from the reformer is switched from the steam generating means to the fuel cell, and is separated from the steam generating means. Fuel from the system can be supplied (claim 6).

  In any one of the above reforming system start-up methods, the fuel of another system supplied to the steam generating means can be anode exhaust gas flowing out from the fuel cell.

  In the start-up method of the reformer that uses the anode fuel flowing out from the fuel cell as the fuel of the different system, the reforming system supplies the reformed gas that is the effluent from the reformer to the fuel cell. A circulation pipe for supplying the anode exhaust gas discharged from the fuel cell as fuel to the water vapor generating means, and a bypass pipe for connecting the reformed gas pipe and the circulation pipe so as to bypass the fuel cell. At start-up, the effluent gas from the reformer is supplied as fuel to the steam generating means via the reformed gas pipe, bypass pipe, and circulation pipe, and when the reformer reaches the reforming operation state, the bypass pipe is closed. The supply of the effluent gas from the reformer can be switched from the steam generating means to the fuel cell.

  In the reforming system starting method provided with the circulation pipe, a condenser is provided in the circulation pipe for supplying fuel to the steam generation means, and the water vapor contained in the gas can be condensed and removed there. ).

  According to the reforming system start-up method of the present invention, as described in claim 1, when starting the reforming system, new raw material gas is continuously supplied to the reformer, and the outflow gas from the reformer is steamed. When the steam is generated from the steam generating means, the steam is mixed with the raw material gas and supplied to the reformer. The temperature of the reformer is raised and the temperature reaches the reforming operation state. Then, the supply of the effluent gas from the reformer is switched from the steam generating means to the fuel cell, and fuel from another system is supplied to the steam generating means. According to this starting method, it is not necessary to provide an incinerator or the like for detoxifying the gas flowing out from the reformer until the reformer reaches normal operation. Further, since the gas flowing out from the reformer can be used effectively, it is not necessary to supply start fuel to the steam generating means when the reforming system is started.

  In the reforming system start-up method, as described in claim 3, it is desirable to supply the steam to the reformer at the start-up before the reformer reaches the carbon deposition temperature. When the temperature of the reformer becomes equal to or higher than the carbon deposition temperature, the raw material gas inside the reformer is carbonized and undesired conditions such as catalyst deterioration occur. Gas carbonization can be effectively prevented.

  In the start-up method of the reformer system, when a self-oxidation internal heating type reformer is used as described in claim 5, before the reformer reaches the carbon deposition temperature, only the main reforming chamber is used. Instead, the raw material gas filled in the preliminary reforming chamber can be replaced with a mixture of the raw material gas and water vapor. In this manner, when the reforming system is started, the presence of water vapor together with the raw material gas in the preliminary reforming chamber can prevent carbonization of the raw material gas in the portion.

  In the start-up method of the reforming system having the self-oxidation internal heating type reformer, as described in claim 6, the mixed catalyst layer is heated and heated with the effluent from the preheater, and the temperature of the mixed catalyst layer is When the oxidation temperature of the raw material gas is reached, oxidizing air is supplied to the mixed catalyst layer and mixed with the effluent from the preheater to oxidize at least a part of the raw material gas, and the mixed catalyst layer is generated by the oxidation heat generated at that time. Can be accelerated. In this way, since the temperature rise of the reformer can be accelerated, the start-up time of the reforming system is further shortened.

  In any one of the above reforming system start-up methods, as described in claim 7, anode exhaust gas flowing out from the fuel cell can be used as a separate fuel supplied to the steam generating means. If it does in this way, the burner of a steam generation means can be used only for gaseous fuel, and the thermal efficiency of a reforming system can be made high.

  9. A method of starting a reforming system in which the fuel of another system is used as an anode exhaust gas flowing out of a fuel cell, and a bypass for connecting a reformed gas pipe and a circulation pipe so as to bypass the fuel cell according to claim 8. When the reforming system is started up, the effluent gas from the reformer is supplied as fuel to the steam generating means through the reformed gas pipe, the bypass pipe, and the circulation pipe, and the reformer enters the reforming operation state. Once reached, the bypass piping can be closed and the supply of effluent gas from the reformer can be switched from the steam generating means to the fuel cell. This simplifies the configuration of the reforming system.

  In the start-up method of the reforming system provided with the circulation pipe, as described in claim 9, a condenser is provided in the circulation pipe for supplying fuel to the steam generating means, and the steam contained in the gas is condensed there. Can be removed. In this way, when the gas flowing out from the reformer when the reforming system is started contains water vapor, the water vapor can be removed to increase the combustion efficiency or thermal efficiency of the water vapor generating means.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a process flow diagram for specifically explaining one example of a method for starting a reforming system of the present invention. The reformer 1 includes an outer preliminary reforming chamber 2 and an inner main reforming chamber 3 arranged in a double cylinder shape, and is formed thin as a whole. Each of the preliminary reforming chamber 2 and the main reforming chamber 3 is elongated and has a flat cross section (in the illustrated example, a flat square shape), and the cross sections thereof are similar to each other. The preliminary reforming chamber 2 is formed between the outer cylinder and the inner cylinder, and the main reforming chamber 3 is formed inside the inner cylinder.

  Note that the reformer 1 to which the present invention can be applied is not limited to such a double structure, and the preliminary reforming chamber 2 and the main reforming chamber 3 are configured as separate bodies, or a preliminary reformer. The present invention can also be applied to a structure in which the steam reforming is performed only in the main reforming chamber 3 without the quality chamber 2. Therefore, the main reforming chamber 3 in the present invention is not limited to the main reforming chamber 3 disposed inside the double structure as shown in FIG. It also means that the main reforming chamber 3 (single reforming chamber) or the like that does not include

  The reforming catalyst layer 4 is provided in the pre-reforming chamber 2, the mixed catalyst layer 5 and the shift catalyst layer 6 in which the reforming catalyst and the oxidation catalyst are mixed are provided in the main reforming chamber 3, and the shift catalyst layer 6 is shifted at a high temperature. The catalyst layer 7 and the low temperature shift catalyst layer 8 are configured. A supply pipe 9 for supplying oxidizing air is extended to the mixed catalyst layer 5 along the central portion of the main reforming chamber 3, and an air ejection portion 10 is provided at an extended portion of the mixed catalyst layer 5. The supply pipe 9 is connected to a pipe 9a for supplying oxidation air, and a heat exchange pipe for heating arranged in a CO selective oxidizer (so-called PROX) 17 described later is provided in the middle of the pipe 9a.

  A raw material-steam mixture supply unit 11 is provided in the lower part of the preliminary reforming chamber 2, and an outflow gas discharge unit 12 such as a reformed gas is provided in the lower part of the main reforming chamber 3. Further, a preheater 13 for activation is connected to the upper part of the main reforming chamber 3. The pre-heater 13 generates a high-temperature gas when the system is started up, and quickly heats the interior of the reformer 1 including the mixed catalyst layer 5 to a normal operation state with the high-temperature gas. An electric heater is disposed inside the pre-heater 13. In addition, an oxidation catalyst such as platinum (Pt) or palladium (Pd) is filled.

  When the reforming system is started, a mixture of raw material gas and start air is supplied to the preheater 13 from the suction mixing means 14 constituted by an ejector, and the raw material gas in the mixture is mixed with oxygen contained in the air in the presence of the oxidation catalyst. The hot gas generated by the reaction and the heat of oxidation flows out to the mixed catalyst layer 5. The hot gas flowing into the mixed catalyst layer 5 heats the interior of the reformer 1 including the mixed catalyst layer 5 and is discharged from the discharge unit 12.

  The discharge unit 12 of the reformer 1 and the fuel cell 15 are communicated with each other through a reformed gas pipe 16, and a CO selective oxidizer 17 is provided in the middle thereof. The CO selective oxidizer 17 is for further reducing CO contained in a small amount in the reformed gas flowing out from the reformer 1 by reacting with oxygen in the air in the presence of an oxidation catalyst. A mixing unit 18 is provided upstream or at the inlet of the CO selective oxidizer 17 to mix the reformed gas flowing out of the reformer 1 and the oxidizing air.

  A reformed gas pipe 16 and an air supply pipe 19 are connected to the fuel cell 15, and hydrogen and air supply pipe 19 that are main components of the reformed gas supplied from the reformed gas pipe 16 during normal operation of the reforming system. Oxygen contained in the air supplied from the reactor reacts in the stack of the fuel cell 15 to generate electricity. The anode exhaust gas generated by the reaction in the fuel cell 15 can flow into the suction mixing means 35 via the circulation pipe 20. A condenser 60 and an on-off valve 20a are provided in the middle of the circulation pipe 20. Further, the water generated in the fuel cell 15 is discharged from the water discharge pipe 21 to the water tank 22, and when the fuel cell 15 needs to be cooled, the cooling water is circulated from the water tank 22 through a circulation path (not shown). The water tank 22 and the drum of the water vapor generating means 30 are connected by a water pipe 23, a pump 24 is provided in the water pipe, and a makeup water pipe 25 is connected to the water tank 22.

  A bypass pipe 26 that connects the reformed gas pipe 16 and the circulation pipe 20 is provided so as to bypass the fuel cell 15, and an open / close valve 27 is provided in the bypass pipe 26. Further, an on-off valve 28 is provided in the middle of the reformed gas pipe 16 that branches from the bypass pipe 26 to the fuel cell 15. The on-off valves 27 and 28 can be opened and closed by remote control from a control device (not shown).

  The steam generating means 30 supplies reforming steam to the reformer 1 and has a combustion section 31 and a drum 32. The combustion unit 31 is provided with a burner 33 and an air pipe 34 for supplying secondary air around the burner 33. The burner 33 is supplied with a mixture of primary air and fuel from a suction mixing means 35 comprising an ejector. The suction mixing means 35 has a fuel pipe 36 for supplying auxiliary fuel, an air pipe 36 a for supplying primary air, and a circulation pipe 20. Is connected. The water vapor generated by the water vapor generating means 30 is supplied to the suction mixing means 14 via the water vapor pipe 37.

  In addition to the water vapor pipe 37, a raw material gas pipe 38 and a start air pipe 39 from a raw material supply unit (not shown) are connected to the suction mixing means 14. A desulfurization device 40 is provided in the middle of the raw material gas pipe 38, where sulfur components contained in the raw material gas are removed. The raw material gas pipe 38 on the outlet side of the desulfurization apparatus 40 is connected to the suction mixing means 14 through a heat exchange pipe provided in the CO selective oxidizer 17.

  The outlet side of the suction mixing means 14 is connected to a pipe 41, and the pipe 41 is branched into two pipes 42 and 43 through a heat exchange pipe provided in the CO selective oxidizer 17. The front end of the pipe 42 communicates with the supply unit 11 of the preliminary reforming chamber 2 in the reformer 1, and an on-off valve 44 capable of adjusting the flow rate is provided in the middle. The distal end of the pipe 43 communicates with the inlet side of the preheater 13, and an on-off valve 45 is provided in the middle. These on-off valves 44 and 45 are opened and closed by remote operation from a control device (not shown).

  Next, a method for starting the reforming system of the present invention will be described with reference to FIG. When starting the reforming system, the on-off valves 45, 27, and 20a are opened, and the on-off valves 28 and 44 are closed. Then, the electric heater of the preheater 13 is energized to start raising the temperature of the internal oxidation catalyst, and the raw material gas is supplied to the suction mixing means 14 from the raw material gas pipe 38. The raw material gas flowing out from the suction mixing means 14 flows into the preheater 13 through the pipes 41 and 43, and then flows out to the mixed catalyst layer 5 of the reformer 1.

  While the reforming system is not operating, the main reforming chamber 3 of the reformer 1 is filled with the raw material gas. However, when the raw material gas flows from the preheater, the main reforming chamber 3 is filled. The raw material gas flows out from the discharge unit 12 to the reformed gas pipe 16 together with the inflowing raw material gas. The outflow gas (the raw material gas at this time) of the reformed gas pipe 16 flows into the suction mixing means 35 through the CO selective oxidizer 17, the bypass pipe 26 and the condenser 60 of the circulation pipe 20. The raw material gas that has flowed into the suction mixing means 35 is mixed with the primary air there, supplied to the burner 33 of the water vapor generating means 30, and burned.

  When the internal temperature of the preheater 13 reaches a temperature (oxidation temperature) at which the oxidation catalyst can oxidize, start air is supplied to the suction mixing means 14 and the mixture of the source gas and start air flowing out from the suction mixing means 14 is supplied. The preheater 13 is supplied. In the preheater 13, the raw material gas reacts (combusts) with oxygen in the start air, and the generated high-temperature gas (oxidized combustion gas, unreacted raw material gas, and relatively little hydrogen) flows into the mixed catalyst layer 5. The high-temperature gas that has flowed into the mixed catalyst layer 5 passes through the shift catalyst layer 6 and heats the mixed catalyst layer 5 and the shift catalyst layer 6 while flowing out from the discharge portion 12 to the reformed gas pipe 16.

  The hot gas that has passed through them is guided to the CO selective oxidizer 17. Air is simultaneously supplied to the inlet of the CO selective oxidizer 17 and reacts with hydrogen in the high temperature gas to heat the inside of the CO selective oxidizer 17. As a result, condensation of the CO selective oxidizer 17 is prevented, and the raw material gas and oxidized air are heated using the CO selective oxidizer 17 as a heat exchanger and supplied to the preheater 13 to reform the reformer. Accelerate the reaction at an accelerated rate.

  When reaching a state where the preheater 13 can be maintained in a temperature range where oxidation reaction can be performed by heating with the high temperature gas generated, the energization of the electric heater of the preheater 13 is stopped and the supply amount of start air to the suction mixing means 14 is increased. Then, the flow rate of the hot gas from the preheater 13 is increased to increase the heating rate of the mixed catalyst layer 5 and the like. However, at this time, the temperature of the mixed catalyst layer 5 and the reforming catalyst layer 4 of the preliminary reforming chamber 2 does not reach the carbon deposition temperature region only by the amount of heat of the high temperature gas from the preheater 13.

  The gas flowing out from the preheater 13 through the reformer 1 into the reforming pipe 16 contains unreacted raw material gas, and the outflow gas is supplied as fuel to the steam generating means 30 through the CO selective oxidizer 17 and the like. The By continuing the combustion of the water vapor generating means 30 in this way, the water vapor generating means 30 is in a state where water vapor of a predetermined pressure can be generated. When the generation of water vapor by the water vapor generating means 30 is started, the supply of start air to the suction mixing means 14 is temporarily stopped, the on-off valve 45 is closed, and the on-off valve 44 is opened.

  By the opening / closing valve operation, water vapor is supplied from the water vapor generating means 30 to the suction mixing means 14, and the mixture of the raw material gas and water vapor flowing out from the suction mixing means 14 is supplied from the pipe 42 to the supply unit 11 of the reformer 1. The mixture passes through the reforming catalyst layer 4 in the preliminary reforming chamber 2 and flows out to the mixed catalyst layer 5. While the reforming system is shut down, the inside of the preliminary reforming chamber 2 is also filled with the raw material gas. By this operation, the inside of the preliminary reforming chamber 2 is replaced with a mixture of the raw material gas and steam. Even if the internal temperature of the preliminary reforming chamber 2 becomes equal to or higher than the carbon deposition temperature, the carbonization of the raw material gas existing in the portion is prevented by the presence of water vapor.

  When the inside of the preliminary reforming chamber 2 is sufficiently replaced with the mixture of the raw material gas and water vapor, the on-off valve 44 is closed and the on-off valve 45 is opened, and the supply of the start air to the suction mixing means 14 is resumed and suction is performed. A mixture of source gas, water vapor, and start air flowing out from the mixing means 14 is supplied to the preheater 13. Since the amount of suction of the start air and the raw material gas is increased by the suction and mixing means 14 due to the suction force of the water vapor, the amount of oxidation heat generated in the preheater 13 also increases.

  While the temperature rise of the mixed catalyst layer 5 is accelerated by the high temperature gas (a mixture of oxidation combustion gas, unreacted raw material gas and water vapor) flowing out from the preheater 13, the shift catalyst layer 6 provided on the downstream side, and further the CO The temperature of the oxidation catalyst layer of the selective oxidizer 17 is raised. The effluent gas from the CO selective oxidizer 17 flows into the condenser 60, where water vapor contained therein is removed by condensation, and then supplied as fuel to the water vapor generating means 30 via the suction mixing means 35.

  When the temperature (oxidation temperature) at which the oxidation reaction of the mixed catalyst layer 5 by the oxidation catalyst is reached, oxidation air can be supplied to the mixed catalyst layer 5 to further accelerate the temperature increase rate. Specifically, by supplying the oxidizing air from the pipe 9 a to the supply pipe 9, the oxidizing air is supplied to the mixed catalyst layer 5 from the ejection portion 10 provided at the tip portion. In the mixed catalyst layer 5, the effluent from the preheater 13 and the oxidizing air are mixed, and at least a part of the raw material gas is oxidized there, and the temperature of the mixed catalyst layer 5 is further accelerated by the oxidation heat generated at that time.

  When the temperature of the mixed catalyst layer 5 reaches a predetermined temperature (for example, about 240 ° C.), the supply of start air to the suction mixing means 14 is stopped, and the on-off valve 45 is closed and the on-off valve 44 is opened. The mixture of raw material gas and water vapor flowing out from the mixing means 14 is switched from the preheater 13 to the supply unit 11 of the reformer 1. Further, the supply amount of oxidized air from the supply pipe 9 is increased. By these operations, the mixture of the raw material gas and the steam flows into the mixed catalyst layer 5 of the main reforming chamber 3 through the pre-reforming chamber 2, where the temperature of the mixed catalyst layer 5 is further increased by the generation of oxidation heat by the oxidizing air. In addition to acceleration, the temperature of the preliminary reforming chamber 2 is also accelerated by heat transfer from the downstream shift catalyst layer 6 and the main reforming chamber 3.

  At this time, a part of the raw material gas is steam reformed in the mixed catalyst layer 5 to generate a reformed gas, but the outflow gas composed of a mixture of the reformed gas and the unreacted raw material gas, steam, etc. is discharged to the discharge unit 12. Then, it flows out to the reformed gas pipe 16 and is supplied as fuel to the steam generating means 30 through the CO selective oxidizer 17, the condenser 60 and the suction mixing means 35.

  When the internal temperature of the reformer 1 further rises and the mixed catalyst layer 5 reaches a reforming temperature region (for example, about 700 ° C.), the reformer 1 enters a normal operation state or a normal operation state. Therefore, when the on-off valve 28 is opened and the on-off valve 27 is closed, the supply of the outflow gas from the reformer 1 (the outflow gas at this time is the hydrogen-rich reformed gas) is switched from the steam generating means 30 to the fuel cell 15. The anode exhaust gas generated in the fuel cell 15 is supplied as fuel from the circulation pipe 20 to the water vapor generating means 30. The start-up of the reforming system is completed by this series of operations.

  Since the fuel cell 15 does not consume all of the hydrogen in the reformed gas, fuel components necessary for the generation of water vapor remain in the anode exhaust gas, and generally the fuel necessary for the water vapor generation means 30 can be provided. it can. In addition, during the start-up operation, auxiliary fuel can be supplied from the pipe 36 to the suction mixing unit 35 at an arbitrary ratio as necessary in order to stabilize the combustion in the water vapor generating unit 30.

  FIG. 2 is a modification of the reforming system shown in FIG. The main parts of the reforming system in FIG. 2 are the same as those in FIG. 1, and the same parts as those in FIG. 2 differs from FIG. 1 in that an ammonia absorption tank 50 is provided in the reformed gas pipe 16 on the outlet side of the CO selective oxidizer 17, a cooling water circulation path is provided in the fuel cell 15, and further to the steam generating means 30. The water supply is not the water tank 22 but the ammonia absorption tank 50, and the rest is the same.

  Water is stored in the ammonia absorption tank 50, and makeup water is supplied from the pipe 51 as necessary. The reformed gas flowing out from the CO selective oxidizer 17 is ejected by bubbling into the water of the ammonia feed water tank 50, where a small amount of ammonia is absorbed by the water and removed. The reformed gas from which ammonia has been removed stays in the upper space in the ammonia absorption tank 50, and the reformed gas is supplied to the fuel cell 15 through the reformed gas pipe 16 and the on-off valve 28. When the reforming system is started up, if the effluent flowing from the reformer 1 through the CO selective oxidizer 17 contains water vapor, the water vapor is condensed and removed in the water of the ammonia absorption tank 50. . The water transferred from the ammonia absorption tank 50 to the pipe 54 by the pump 24 is supplied as make-up water to the water vapor generating means 30. If water vapor remains in the water, it can be removed by the condenser 60 if necessary.

  On the other hand, cooling water from the fuel cell 15 flows into the water tank 22 through the pipe 21, and water in the water tank 22 is supplied to the fuel cell 15 as cooling water through the pipe 53 provided with the pump 52. That is, the cooling water circulation path is formed by the pipe 21, the pipe 53, and the pump 52, and the pipe 21 also serves as the drainage pipe of the fuel cell 15.

  The start-up method of the present invention can be used in a reforming system in which a raw material gas is steam reformed to generate a hydrogen-rich reformed gas and supplied to a fuel cell.

The process flow figure for demonstrating the starting method of the reforming system of this invention. The process flow figure for demonstrating the starting method of the other reforming system of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reformer 2 Preliminary reforming chamber 3 Main reforming chamber 4 Reforming catalyst layer 5 Mixed catalyst layer 6 Shift catalyst layer 7 High temperature shift catalyst layer 8 Low temperature shift catalyst layer 9 Supply pipe 9a Piping

DESCRIPTION OF SYMBOLS 10 Jet part 11 Supply part 12 Discharge part 13 Preheater 14 Suction mixing means 15 Fuel cell 16 Reformed gas piping 17 CO selective oxidizer 18 Mixing part 19 Air supply pipe

20 Circulation Piping 20a On-off Valve 21 Water Discharge Pipe 22 Water Tank 23 Water Piping 24 Pump 25 Supply Water Piping 26 Bypass Piping 27, 28 On-off Valve

Reference Signs List 30 Steam generating means 31 Combustion section 32 Drum 33 Burner 34 Air piping 35 Suction mixing means 36 Fuel piping 36a Air piping 37 Steam piping 38 Raw material gas piping 39 Start air piping

40 Desulfurizer 41-43 Piping 44, 45 On-off valve 50 Ammonia absorption tank 51 Piping 52 Pump 53, 54 Piping 60 Condenser

Claims (9)

A reformer 1 for generating hydrogen-rich reformed gas from a mixture of a raw material gas and water vapor generated by the water vapor generating means 30 and supplying the fuel cell 15 with the water vapor generating means 30 for burning the fuel to generate water vapor In the starting method of the reforming system comprising
When the reforming system is started, new raw material gas is continuously supplied to the reformer 1, the outflow gas from the reformer 1 is supplied as fuel to the steam generating means 30, and steam is generated from the steam generating means 30. Then, the water vapor is mixed with the raw material gas and supplied to the reformer 1. The temperature of the reformer 1 is raised, and when the temperature reaches the state where the reforming operation is possible, supply of the outflow gas from the reformer 1 Is switched from the steam generating means 30 to the fuel cell 15, and the steam generating means 30 is supplied with fuel from another system.     In Claim 1, the raw material gas is continuously supplied to the reformer 1 at the time of start-up, the outflow gas from the reformer 1 is supplied as the fuel of the steam generating means 30, and the auxiliary fuel is vaporized from the auxiliary fuel pipe 36. A method for starting a reforming system, characterized in that the reforming system is supplied as part of the fuel of the generating means (30).   3. The reforming system start-up method according to claim 1, wherein the steam is supplied to the reformer 1 before the reformer 1 reaches the carbon deposition temperature.   In claim 3, the reformer 1 includes a pre-reformer chamber 2 and a main reforming chamber 3, the reforming catalyst layer 4 is provided in the pre-reforming chamber 2, and the main reforming chamber 3 includes A mixed catalyst layer 5 in which a reforming catalyst and an oxidation catalyst are mixed is provided at least, and a mixture of a raw material gas and water vapor is supplied to the pre-reforming chamber 2, and the mixed catalyst layer 5 has an outflow gas from the pre-reforming chamber 2 A method for starting a reforming system, characterized by being a self-oxidation internal heating type configured to be supplied with oxidizing air and to supply a reformed gas flowing out from a main reformer 3 to a fuel cell 15. In claim 4, during the stoppage of the reforming system, the preliminary reforming chamber 2 and the main reforming chamber 3 are filled with the raw material gas,
When the reforming system is started, before the reformer 1 reaches the carbon deposition temperature, the reforming system is characterized in that the source gas filled in the preliminary reforming chamber 2 is replaced with a mixture of source gas and steam. How to start. 6. The reforming system according to claim 5, further comprising a suction mixing means 14 for mixing the raw material gas and water vapor or start air, and a preheater 13 comprising an oxidation catalyst and a heater, wherein the raw material gas or the mixture of the raw material gas and water vapor is Supplied to the reformer 1 via the suction mixing means 14 and the preheater 13;
At the start of the reforming system, the raw material gas and the starting air are supplied to the preheater 13, the mixed catalyst layer 5 is heated and heated with the effluent from the preheater 13, and the temperature of the mixed catalyst layer 5 becomes the oxidation temperature of the raw material gas. When it reaches, oxidizing air is supplied to the mixed catalyst layer 5 and mixed with the effluent from the preheater 13 to oxidize at least a part of the raw material gas, and the temperature of the mixed catalyst layer 5 is increased by oxidation heat generated at that time. Accelerate,
When water vapor is generated from the water vapor generating means 30, the water vapor is supplied to the suction mixing means 14 together with the raw material gas, the supply of the start air to the suction mixing means 14 is stopped, and the raw material gas flowing out from the suction mixing means 14 When the reformer 1 reaches the reforming operation state, the effluent gas from the reformer 1 is supplied from the steam generating means 30 to the fuel cell. 15. A reforming system start-up method, wherein the steam generation means 30 is supplied with fuel from another system.   7. The reforming system start-up method according to claim 1, wherein the fuel of another system supplied to the steam generating means 30 is anode exhaust gas flowing out of the fuel cell 15. 7. The reforming system according to claim 7, wherein the reforming system uses the reformed gas pipe 16 for supplying the outflow gas from the reformer 1 to the fuel cell 15, and the anode exhaust gas discharged from the fuel cell 15 as fuel for the steam generating means 30. A circulation pipe 20 to be supplied, and a bypass pipe 26 for connecting the reformed gas pipe 16 and the circulation pipe 20 so as to bypass the fuel cell 15;
When the reforming system is started, the effluent gas from the reformer 1 is supplied as fuel to the steam generation means 30 through the reformed gas pipe 16 -bypass pipe 26 -circulation pipe 20 and the reformer 1 reforms. A method for starting a reforming system, characterized in that when the operating state is reached, the bypass pipe 26 is closed and the supply of the outflow gas from the reformer 1 is switched from the steam generating means 30 to the fuel cell 15.   9. The reforming system start-up method according to claim 8, wherein a condenser 60 is provided in the circulation pipe 20 for supplying fuel to the water vapor generating means 30, and the water vapor contained in the gas is condensed and removed there.

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