JP2009184896A - Hydrogen production device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen production device which can stably control combustion heat capacity in a combustor, and can hold the temperature of a reforming catalyst layer to the optimum state. <P>SOLUTION: The hydrogen production device comprises: a reforming apparatus 10 provided with a reforming catalyst layer 32 and a combustor 14 provided with a burner 13 burning air for burner combustion and fuel for burner combustion and utilizing the combustion exhaust gas therefrom as a heating medium of the reforming catalyst layer 32; an air flow rate meter F2 and an air flow rate regulating valve V2 arranged at the feed line L2 of the air for burner combustion; a fuel flow rate meter F1 and a fuel flow rate regulating valve V1 arranged at the feed line L1 of the fuel for burner combustion; a heater 18 heating the air for burner combustion; a temperature measuring means measuring the temperature in the reforming apparatus; and a controller 60 at least performing the control of the fuel flow rate regulating valve V1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrogen production apparatus provided with a reformer.

  In an industrial device or a fuel cell power plant that uses hydrogen as an atmospheric gas, a hydrogen generator is required. As one of the hydrogen generators, a reformer having a reforming catalyst layer for steam reforming a reforming raw material containing hydrocarbons and steam to generate a reformed gas containing hydrogen, and for pressurizing the reformed gas And a pressure swing adsorption device (PSA) that separates and purifies hydrogen from the pressurized reformed gas. Also, the reformer is equipped with a combustor with a burner, and burner combustion air and burner combustion fuel are combusted in the combustor, and reformed by the combustion exhaust gas and combustion heat discharged at that time. The structure which heats a catalyst layer is mainly employ | adopted.

  Here, as the burner combustion fuel, the PSA residual gas discharged from the PSA when the reformed gas is separated and purified by PSA, the fuel cell exhaust gas discharged when used for power generation in the fuel cell, etc. Exhaust gas containing hydrogen (hereinafter referred to as “hydrogen-containing exhaust gas”) may be used.

  However, the hydrogen-containing exhaust gas has a tendency that the hydrogen concentration is unstable and fluctuates. If too much hydrogen is supplied to the combustor, the reforming catalyst layer may be overheated, resulting in a decrease in catalyst life, or damage to the combustor or other ancillary equipment due to thermal damage. . In addition, if the required amount of hydrogen is not supplied to the combustor, the reforming catalyst layer may not be heated sufficiently, and hydrocarbon steam reforming may not be performed efficiently.

For this reason, in order to carry out the steam reforming reaction of hydrocarbons stably, the temperature inside the reformer is measured, and the supply amount of the burner combustion fuel is adjusted so that the temperature inside the reformer becomes a predetermined temperature. For example, as disclosed in Patent Document 1 below, a method of analyzing the gas composition of the burner combustion fuel and adjusting the supply amount of the burner combustion fuel to the combustor according to the hydrogen concentration is performed. It has been broken.
JP 2003-63802 A

  In order to maintain the inside of the reformer at a predetermined temperature, the flow rate of the burner combustion fuel is adjusted to control the amount of combustion heat in the burner, and the burner combustion fuel and burner combustion air jump speeds from the burner nozzle ( It is necessary to adjust the mixing intensity by adjusting each flow rate to keep the burner flame in an appropriate state. If the mixing strength is lower than the set range, the burner flame becomes elongated and the reforming catalyst layer cannot be efficiently heated, so that the reaction heat cannot be sufficiently supplied or the combustor may be overheated. When the mixing strength exceeds the set range, the burner flame is shortened, a hot spot is generated, and the reforming catalyst layer may be locally overheated.

  By the way, when hydrogen-containing exhaust gas is used as the burner combustion fuel, the hydrogen concentration tends to fluctuate. For this reason, in the method of adjusting the fuel heat quantity by adjusting the flow rate of the burner combustion fuel, the flame state of the burner becomes unstable, the combustion heat quantity in the combustor cannot be stably controlled, and the combustor is locally In some cases, the reforming catalyst layer could not be heated sufficiently.

  Further, as in Patent Document 1, if the method is to analyze the gas composition of the burner combustion fuel and adjust the supply amount of the burner combustion fuel to the combustor according to the gas composition, the amount of combustion heat in the combustor However, since gas analyzers such as hydrogen concentration measuring instruments are expensive, there is a problem that the apparatus cost and the maintenance cost increase.

  Therefore, an object of the present invention is to stably control the amount of combustion heat in the combustor without using expensive equipment such as a hydrogen concentration measuring instrument, and to suppress the overheating of the combustor and the temperature of the reforming catalyst layer. An object of the present invention is to provide a hydrogen production apparatus capable of maintaining the optimal state.

In order to achieve the above object, a hydrogen production apparatus of the present invention comprises a reforming catalyst layer for steam reforming a reforming raw material containing hydrocarbons and steam to produce a reformed gas containing hydrogen, burner combustion air, A hydrogen production apparatus comprising a reformer having a combustor in which a burner using combustion exhaust gas discharged by burning a burner combustion fuel as a heating medium for the reforming catalyst layer is disposed,
An air flow meter and an air flow rate adjustment valve disposed in the burner combustion air supply line;
A fuel flow meter and a fuel flow rate adjustment valve disposed in the burner combustion fuel supply line;
A heater for heating the burner combustion air;
Temperature measuring means for measuring the temperature in the reformer;
A control device for at least controlling the fuel flow rate regulating valve,
The control device calculates a hydrogen concentration in the burner combustion fuel from the measured values of the temperature measuring means and the fuel flow meter, and when the calculated hydrogen concentration exceeds a predetermined set value. , (A) reducing the opening of the fuel flow control valve, (B-1) increasing the opening of the air flow control valve, and / or (B-2) increasing the heating amount by the heater. When the calculated hydrogen concentration falls below a predetermined set value, (C) the degree of opening of the fuel flow rate adjustment valve is increased, and (D-1) the air flow rate adjustment is performed. The valve opening is reduced and / or (D-2) is controlled to reduce the amount of heating by the heater,
It is characterized by that.

  According to the hydrogen production apparatus of the present invention, when the temperature in the reformer is measured with the flow rate of the burner combustion fuel constant, the temperature in the reformer increases as the hydrogen concentration in the burner combustion fuel increases or decreases. Increase or decrease. For this reason, even when a gas with large fluctuations in hydrogen concentration, such as hydrogen-containing exhaust gas, is used as the burner combustion fuel, the measured value of the fuel flow meter and the temperature measuring means arranged in the reformer From the measured value, the hydrogen concentration in the burner combustion fuel can be calculated. And based on this measured value, when the predetermined set value is exceeded, the opening degree of the fuel flow rate adjustment valve is reduced and the opening degree of the air flow rate adjustment valve is increased, and / or by the heater. When the amount of heating is increased and the measured value falls below the set value, the opening of the fuel flow control valve is increased and the opening of the air flow control valve is decreased and / or heating is performed. By controlling so that the amount of heating by the combustor is reduced, the flame state of the burner in the combustor can be stably controlled, and the temperature of the reforming catalyst layer can be maintained at an optimum state without overheating the combustor. it can.

  The temperature measuring means of the hydrogen production apparatus of the present invention is arranged to measure at least one of the temperature in the vicinity of the outlet side of the reforming catalyst layer, the flame temperature of the burner, and the temperature in the combustor. It is preferable. According to this aspect, since the hydrogen concentration in the burner combustion fuel can be calculated with higher accuracy, the flame state of the burner in the reformer can be stably controlled, and the reforming catalyst is not overheated. The temperature of the layer can be kept more optimal.

  In the hydrogen production apparatus of the present invention, a pressure swing adsorption device that pressurizes the reformed gas discharged from the reformer and separates and purifies hydrogen from the reformed gas downstream of the reformer on the reformed gas discharge side. The residual gas after separation and purification of hydrogen from the reformed gas is supplied to the combustor and used as the burner combustion fuel gas in the pressure swing adsorption device. preferable. In the pressure swing adsorption device, the residual gas after separation and purification of hydrogen from the reformed gas is likely to vary in hydrogen concentration depending on operating conditions such as the inlet pressure of the pressure swing adsorption device and the timing of adsorption and desorption. According to the method, it is particularly preferable because the temperature in the reformer can be brought into an optimum state without adding expensive equipment such as hydrogen concentration measurement.

  According to the hydrogen production apparatus of the present invention, the amount of combustion heat in the combustor can be stably controlled without using expensive equipment such as a hydrogen concentration measuring instrument, and the reforming catalyst layer is suppressed by suppressing overheating of the combustor. Can be maintained at an optimum state.

  The hydrogen production apparatus of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing an embodiment of the hydrogen production apparatus of the present invention, and FIG. 2 is a schematic diagram of a reformer used in the hydrogen production apparatus.

  As shown in FIG. 1, the hydrogen production apparatus includes a reformer 10, a PSA 50, and a controller 60.

  Referring also to FIG. 2, a combustor including a gas cylinder 11 and a burner cylinder 12 formed integrally on the central axis of the reformer 10, and a burner 13 that forms a flame downward in the interior. 14 is arranged.

  In the gas cylinder 11 of the combustor 14, a burner combustion fuel supply path 15 for supplying burner combustion fuel to the burner 13 and a burner combustion air supply path 16 for supplying burner combustion air to the burner 13 are formed. ing. A fuel introduction port 15 a is formed at the upstream end portion of the burner combustion fuel supply passage 15, and an air introduction port 16 a is formed at the upstream end portion of the burner combustion air supply passage 16.

  A pipe L1 extending from the residual gas discharge side of the PSA 50, which will be described later, is connected to the fuel inlet 15a, and a flow meter F1 and a valve V1 are disposed in the pipe L1.

  A pipe L2 extending from an air supply source is connected to the air introduction port 16a, and a flow meter F2, a valve V2, and a heater 18 are disposed in the pipe L2. Examples of the heater 18 include an electric heater and a heat exchanger.

  The burner 13 is provided with a thermometer T1 for measuring the flame temperature.

  An inner cylinder 20 having a diameter larger than that of the combustor 14 and having a bottom surface is disposed outside the combustor 14 having the above-described configuration, and a combustion exhaust gas flow path is formed by a gap between the combustor 14 and the inner cylinder 20. 21 is formed. A combustion exhaust gas discharge port 21 a is formed at the downstream end of the combustion exhaust gas passage 21. The internal space of the burner cylinder 12 and the combustion exhaust gas passage 21 communicate with each other through a gap 20 a provided between the lower end of the burner cylinder 12 and the bottom surface of the inner cylinder 20. A thermometer T2 is disposed in the vicinity of the gap 20a.

  An outer cylinder 30 having a bottom surface is disposed on the outer side of the inner cylinder 20 with a gap between the inner cylinder 20 and the outer cylinder 30. A partition wall 31 is provided between the inner cylinder 20 and the outer cylinder 30, and the inner cylinder 20 and the outer cylinder 30 are divided into two concentric annular spaces, and both annular spaces are outside. The cylinder 30 communicates with a gap 31a provided between the bottom surface of the cylinder 30 and the lower end of the partition wall 31.

  The annular space between the inner cylinder 20 and the partition wall 31 is filled with a reforming catalyst to form a reforming catalyst layer 32.

  The annular space on the upstream side of the reforming catalyst layer 32 forms a reforming material supply path 33 for supplying the reforming material (hydrocarbon + steam) to the reforming catalyst layer 32. A reforming material supply port 33a is formed at the upstream end. A thermometer T3 is disposed in the vicinity of the outlet of the reforming catalyst layer 32.

  An annular space between the partition wall 31 and the outer cylinder 30 forms a reformed gas supply path 34, and a reformed gas recovery port 34 a is formed at the downstream end of the reformed gas supply path 34. . A piping L3 extends from the reformed gas recovery port 34a and is connected to the compression device 40.

  A PSA 50 is disposed on the downstream side of the compression device 40, and the compression device 40 and the PSA 50 are connected via a pipe L4.

  The PSA 50 is an apparatus for purifying hydrogen by filling a plurality of containers with an adsorbent such as activated carbon or zeolite and by adsorbing and separating a specific gas species by changing the pressure. From the residual gas discharge side of the PSA 50, the pipe L1 extends and is connected to the fuel inlet 15a of the reformer 10 as described above. From the purified hydrogen discharge side of the PSA 50, the pipe L5 extends so that the purified hydrogen can be recovered by a hydrogen holder or the like (not shown).

  The opening degree of the valves V1 and V2 and the amount of heating by the heater 18 are controlled by the control device 60.

  The control device 60 is mainly composed of a microcomputer, and includes a well-known CPU, RAM, ROM, I / O interface, and the like. Flow meters F1, F2, and thermometers T1, T2, T3 are connected to the input side of the I / O interface.

  Next, a hydrogen production method using such a hydrogen production apparatus will be described. In addition, the arrow in FIG. 2 shows the flow direction of each fluid.

  First, a gas containing hydrocarbons is supplied to the combustor 14 from the fuel inlet 15a to the burner combustion fuel supply passage 15 as a burner combustion fuel. Also, burner combustion air is supplied to the burner combustion air supply passage 16 from the air inlet 16a. Then, each flows downward in the vertical direction and burns in the burner 13, and the reforming catalyst layer 32 is heated by the combustion heat. At this time, the flue gas discharged from the combustor 14 passes through the flue gas passage 21 and is discharged out of the system from the flue gas discharge port 21a.

  The reforming catalyst layer 32 is supplied with a reforming material in which hydrocarbon and steam are mixed at a predetermined ratio from the reforming material supply port 33a.

  The reforming catalyst layer 32 is heated to about 400 ° C. to 650 ° C. by the combustion exhaust gas flowing inside, and here, steam and hydrocarbon are subjected to steam reforming reaction to generate reformed gas rich in hydrogen. .

  The reformed gas generated in the reformer 10 is supplied from the pipe L3 to the compressor 40, where it is pressurized to a predetermined pressure and then supplied to the PSA 50 to separate and purify hydrogen from the reformed gas, The refined hydrogen is recovered from the pipe L5 by a hydrogen holder (not shown) to obtain raw material, atmosphere gas, etc. for semiconductor manufacturing, metal refining, oil production, oil refinery / chemical industry, etc., as well as driving power or power for automobiles. Use as fuel for. On the other hand, the residual gas after separating hydrogen from the reformed gas is introduced into the combustor 14 through the pipe L1 and used as a burner combustion fuel gas.

  In this embodiment, the control device 60 controls the supply of burner combustion fuel and burner combustion air to the combustor 14 by controlling the degree of opening and closing of the valves V1 and V2 and the amount of heating in the heater 18. Hereinafter, the control in the control device 60 will be described with reference to the flowchart of FIG.

  First, in step S1, it is determined whether there is a change in the measured value of the flow meter F1. If there is a change in the measured value of the flow meter F1, in step S2, the opening of the valve V1 is adjusted to make the measured value of the flow meter F1, that is, the flow rate of the burner combustion fuel constant.

  If there is no change in the measured value of the flow meter F1, it is determined in step S3 whether there is a change in the measured value of the flow meter F2. If there is a change in the measured value of the flow meter F2, in step S4, the opening of the valve V2 is adjusted to make the measured value of the flow meter F2, that is, the flow rate of the burner combustion air constant.

  If there is no change in the measured value of the flow meter F2, it is determined in step S5 whether there is a change in the heating amount of the heater 18. If the heating amount of the heater 18 varies, in step S6, the heating amount of the heater 18 is adjusted to be constant.

  If there is no change in the heating amount of the heater 18, it is determined in step S7 whether the measured values of the thermometers T1, T2, T3 exceed the set value upper limit. If the measured values of the thermometers T1, T2, T3 exceed the set value upper limit, in step S8, the opening of the valve V1 is decreased and the flow rate of the burner combustion fuel is decreased. In step S9, it is determined whether the measured values of the thermometers T2 and T3 exceed the set value upper limit. If so, the process returns to step S8, and the opening of the valve V1 is decreased. If it is within the set range, the process proceeds to step S10 or step S11. In step S10, the opening degree of the valve 2 is increased and the flow rate of the burner combustion air is increased. In step S11, the heating amount in the heater 18 is increased to increase the temperature of the burner combustion air. And after performing the process of step S10 or S11, it is judged whether the measured value of the thermometer T1 remove | deviates from a setting range in step S12. If it is out of the set range, the process of step S10 or step S11 is performed again, and if it is within the set range, the process ends.

  On the other hand, if the measured values of the thermometers T1, T2, T3 do not exceed the set value upper limit in step S7, the measured values of the thermometers T1, T2, T3 fall below the set value lower limit in step S13. Judge. If the measured values of the thermometers T1, T2, T3 do not fall below the lower limit of the set value, the process ends. If the measured values of the thermometers T1, T2, T3 are below the lower limit of the set value, the opening of the valve V1 is increased in step S14 to increase the flow rate of the burner combustion fuel. In step S15, it is determined whether the measured values of the thermometers T2 and T3 are lower than the set value. If the measured values are lower, the process returns to step S14 to increase the opening of the valve V1. If it is within the setting range, the process proceeds to step S16 or step S17. In step S16, the opening degree of the valve V2 is reduced to reduce the flow rate of the burner combustion air. In step S17, the heating amount in the heater 18 is reduced to lower the temperature of the burner combustion air. And after performing the process of step S16 or S17, it is judged whether the measured value of the thermometer T1 remove | deviates from a setting range in step S18. If it is out of the set range, the process of step S16 or step S17 is performed again, and if it is within the set range, the process ends.

  According to the hydrogen production apparatus of the present invention, since the increase / decrease in the hydrogen concentration of the burner combustion fuel is calculated from the measurement values of the thermometers T1, T2, T3 and the measurement values of the flow meters F1, F2, a hydrogen concentration meter, etc. An expensive measuring instrument such as is unnecessary.

  When the measured values of the thermometers T1, T2, and T3 exceed the upper limit of a predetermined set value, the opening of the valve V1 is reduced to reduce the flow rate of the burner combustion fuel, and the valve V2 To increase the flow rate of the burner combustion air and / or increase the amount of heating by the heater 18 to increase the temperature of the burner combustion air. Although the amount of heat generated in the combustor 14 is reduced by reducing the flow rate of the burner combustion fuel, the mixing strength is reduced, the burner flame is elongated, and the heating efficiency of the reforming catalyst layer 32 is reduced. For this reason, if it controls to raise the temperature of the reforming catalyst layer 32 to a predetermined temperature, the combustor 14 is overheated and the combustor 14 is thermally damaged. However, in the present invention, the opening of the valve V1 is reduced to reduce the flow rate of the burner combustion fuel, and the opening of the valve V2 is increased to increase the flow rate of the burner combustion air, and / or heating. Therefore, when the flow rate of the burner combustion air is increased, the mixing strength between the burner combustion fuel and the burner combustion air is increased. Therefore, the burner flame can be stabilized. In addition, when the temperature of the burner combustion air is increased, the expansion rate of the burner combustion fuel and the burner combustion air from the burner nozzle increases due to volume expansion, thereby increasing the mixing strength and reducing the burner flame. It can be stabilized. For this reason, the reforming catalyst layer 32 can be heated uniformly without overheating the combustor 14.

  On the other hand, when the measured values of the thermometers T1, T2, and T3 are below the lower limit of a predetermined set value, the opening of the valve V1 is increased to increase the flow rate of the burner combustion fuel, and the valve V2 Is controlled so as to reduce the flow rate of the burner combustion air by decreasing the opening degree and / or to reduce the temperature of the burner combustion air by reducing the amount of heating by the heater 18. Increasing the flow rate of the burner combustion fuel increases the amount of heat generated in the combustor 14, but the mixing strength is increased, the burner flame is shortened, and a hot spot is generated in the vicinity of the burner. In the present invention, the opening of the valve V2 is increased to reduce the flow rate of the burner combustion fuel, and the opening of the valve V2 is reduced to reduce the flow rate of the burner combustion air. In addition, since the heating amount by the heater 18 is decreased to control the temperature of the burner combustion air, the burner combustion fuel and the burner combustion fuel are reduced when the flow rate of the burner combustion air is decreased. An increase in mixing strength with air can be suppressed, and the burner flame can be stabilized. In addition, when the temperature of the burner combustion air is lowered, the jumping speed of the burner combustion fuel and burner combustion air from the burner nozzle can be reduced, thereby suppressing an increase in mixing strength and stabilizing the burner flame. Can be made. For this reason, the reforming catalyst layer 32 can be heated uniformly without overheating the combustor 14.

It is the schematic showing one Embodiment of the hydrogen production apparatus of this invention. It is the schematic of the reformer used for the hydrogen production apparatus. It is a flowchart figure which shows the control method in a control apparatus.

Explanation of symbols

10: reformer 11: gas cylinder 12: burner cylinder 13: burner 14: combustor 15: burner combustion fuel supply path 15a: fuel inlet 16: burner combustion air supply path 16a: air inlet 18: heater 20: Inner cylinder 20a: Gap 21: Combustion exhaust gas flow path 21a: Combustion exhaust gas discharge port 30: Outer cylinder 31: Partition wall 31a: Gap 32: Reforming catalyst layer 33: Reforming raw material supply path 33a: Reforming raw material supply port 34 : Reformed gas supply path 34a: Reformed gas recovery port 40: Compressor 60, 61: Controllers F1, F2: Flow meters T1-T3: Thermometers V1, V2: Valves

Claims (3)

A reforming catalyst layer for steam reforming a reforming raw material containing hydrocarbons and steam to produce a reformed gas containing hydrogen, and combustion exhaust gas discharged by burning burner combustion air and burner combustion fuel. A hydrogen production apparatus comprising a reformer having a combustor in which a burner used as a heating medium for the reforming catalyst layer is disposed,
An air flow meter and an air flow rate adjustment valve disposed in the burner combustion air supply line;
A fuel flow meter and a fuel flow rate adjustment valve disposed in the burner combustion fuel supply line;
A heater for heating the burner combustion air;
Temperature measuring means for measuring the temperature in the reformer;
A control device for at least controlling the fuel flow rate regulating valve,
The control device calculates a hydrogen concentration in the burner combustion fuel from the measured values of the temperature measuring means and the fuel flow meter, and when the calculated hydrogen concentration exceeds a predetermined set value. , (A) reducing the opening of the fuel flow control valve, (B-1) increasing the opening of the air flow control valve, and / or (B-2) increasing the heating amount by the heater. When the calculated hydrogen concentration falls below a predetermined set value, (C) the degree of opening of the fuel flow rate adjustment valve is increased, and (D-1) the air flow rate adjustment is performed. The valve opening is reduced and / or (D-2) is controlled to reduce the amount of heating by the heater,
The hydrogen production apparatus characterized by the above-mentioned.   The temperature measuring means is arranged to measure at least one of the temperature in the vicinity of the outlet side of the reforming catalyst layer, the flame temperature of the burner, and the temperature in the combustor. 2. The hydrogen production apparatus according to 2. A pressure swing adsorption device for pressurizing the reformed gas discharged from the reformer and separating and purifying hydrogen from the reformed gas is disposed downstream of the reformer on the reformed gas discharge side,
The pressure swing adsorption device is configured to supply residual gas after separation and purification of hydrogen from reformed gas to the combustor to be used as the burner combustion fuel gas. 2. The hydrogen production apparatus according to 2.