JPH05135793A - Combustion control device for fuel cell power generating facilities - Google Patents

Abstract

PURPOSE:To eliminate a control response delay to combustion apparatuses by controlling the flow adjusting valve of an auxiliary fuel feed path with the command signal converted from the deviation signal between the temperature detection signal and the temperature set signal. CONSTITUTION:The deviation between the detection signal 46 of a temperature detector 45 provided at the combustion gas outlet of combustion apparatuses 4, 9 and the set signal 48 of a setter 47 is obtained by a subtracter 49. This deviation signal 50 is converted into the command signal 51 by a proportional integration controller 52, and the opening of the flow adjusting valve 37 of an auxiliary fuel feed path is controlled via multipliers 53, 54. The change rate of the signal 46 is obtained by a differentiator 56, the change rate signal 57 is compared with a preset value by a monitor 60, the switching signal is fed to switching relays 69, 70 based on the result, and the gains from gain setters 61-64 are switched and fed to the multipliers 53, 54 to correct the signal 51. A control response delay to combustion apparatuses 4, 9 is eliminated, and the burning of a catalyst combustor or the like is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control device for fuel cell power generation equipment.

[0002]

2. Description of the Related Art A fuel cell power generation facility A is as shown in FIG.

That is, the temperature of the natural gas 1 is raised by feeding the natural gas 1 to the low temperature side of the fuel preheater 3 through the fuel gas supply passage 2, and then the natural gas 1 is fed to the reformer 4. Reforming side 5
To generate a fuel gas containing hydrogen and carbon monoxide as main components by decomposing the natural gas 1 with high heat and feeding the fuel gas to the high temperature side of the fuel preheater 3. The natural gas 1 supplied to the low temperature side of the preheater 3 is heated, and the fuel gas is fed to the anode 7 (negative electrode) of the fuel cell body 6.
It is used for power generation by the fuel cell main body 6 by being sent to.

The used fuel gas discharged from the anode 7 of the fuel cell body 6 is fed to the catalytic combustor 9 through the fuel gas discharge passage 8, and the used fuel gas in the catalytic combustor 9 will be described later. A high temperature combustion gas is generated by burning with oxygen in the used oxidant gas, and the high temperature combustion gas is passed through the cathode bypass passage 11 to the reformer 4
Of the natural gas supplied to the reforming side 5 of the reformer 4 and used for decomposing the natural gas.

The combustion gas discharged from the combustion side 10 of the reformer 4 is sent to the high temperature side of the air preheater 12 via the cathode bypass passage 11 and then to the steam separator 14. After the water content 15 is removed by this, it is introduced into the oxidant gas supply path 17 by the low temperature blower 16.

On the other hand, the air 19 taken in by the compressor 20 is sent through the air supply passage 21 while being compressed by the compressor 20, and is guided to the oxidant gas supply passage 17.

The oxidant gas containing carbon dioxide in the combustion gas from the cathode bypass passage 11 and oxygen in the air 19 from the air supply passage 21 as a main component is passed through the oxidant gas supply passage 17 to the air preheater. By being fed to the low temperature side of 12, the temperature is raised by the heat of the combustion gas flowing through the cathode bypass passage 11, and the cathode 23 (positive electrode) of the fuel cell main body 6 is heated.
It is used for power generation by the fuel cell body 6 by being sent to the fuel cell body 6.

The used oxidant gas discharged from the cathode 23 of the fuel cell main body 6 is fed to the turbine 25 through the oxidant gas discharge passage 24, whereby the turbine 2
5 is driven to rotate the compressor 20, and then discharged to the outside of the system and guided to an exhaust heat recovery device (not shown).

A part of the used oxidant gas flowing through the oxidant gas discharge passage 24 is circulated and used for controlling the reaction in the cathode 23 through the circulation flow passage 26 and the high temperature blower 27 on the way, and oxygen is supplied. It is delivered to the catalytic combustor 9 via line 28 as described above.

Reference numeral 29 in the drawing denotes a bypass passage for bypassing the inlet / outlet side of the turbine 25 of the oxidant gas discharge passage 24, and 30, 3
Reference numerals 1 and 32 are valves.

The catalyst combustor 9 is provided with a temperature control device as shown in FIG.

That is, the auxiliary fuel supply passage 34 for supplying the auxiliary fuel 33 is connected to the catalytic combustor 9, and the air supply passage 36 for supplying the air 35 is connected to the catalytic combustor 9 in the same manner. 34 and flow control valves 37 and 38 respectively in the middle of the air supply passage 36, a temperature controller 39 is provided in the cathode bypass passage 11 connected to the outlet side of the catalyst combustor 9, and a control signal from the temperature controller 39 is provided. Flow control valve 3 provided in the auxiliary fuel supply passage 34 based on 40
7 is adjusted, and the control device 43 sends a control signal 44 based on a flow rate detection signal 42 from a flow meter 41 provided on the downstream side of the flow rate adjusting valve 37 to send a control signal 44.
The opening degree of the flow rate adjusting valve 38 provided in 6 is adjusted to keep the temperature of the combustion gas on the outlet side of the catalytic combustor 9 constant.

The flow rate adjusting valve 38 provided in the air supply passage 36, like the flow rate adjusting valve 37 provided in the auxiliary fuel supply passage 34, is provided with a separate temperature controller in the cathode bypass passage 11 for control. Alternatively, the opening may be adjusted by multiplying the control signal 40 from the temperature controller 39, which adjusts the opening of the flow rate adjustment valve 37 provided in the auxiliary fuel supply passage 34, with a gain.

Further, the temperature control device may be applied to the reformer 4.

[0015]

However, the above-mentioned conventional combustion control apparatus for fuel cell power generation equipment has the following problems.

That is, by providing the temperature controller 39 on the combustion gas outlet side of the combustion equipment such as the catalytic combustor 9,
Since the opening degree of the flow rate adjusting valve 37 and the like is feedback-controlled, there is a response delay in the control, and there is a risk of burning the catalytic combustor 9 and the like.

In view of the above situation, it is an object of the present invention to provide a combustion control device for a fuel cell power generation facility which can eliminate a response delay in control of combustion equipment.

[0018]

According to the present invention, a temperature detector 45 is provided on the combustion gas outlet side of the combustion devices 4 and 9 provided in the fuel cell power generation facility A, and the temperature detector 45 detects the temperature. A subtractor 49 for taking a deviation between the signal 46 and the temperature setting signal 48 from the setter 47 is provided, and the proportional-plus-integral controller 52 for converting the deviation signal 50 from the subtractor 49 into a command signal 51.
And sending the command signal 51 to the flow rate adjusting valve 37 of the auxiliary fuel supply path 34 connected to the combustion equipment 4, 9 via the multipliers 53, 54, and the temperature from the temperature detector 45. Differentiator 5 for obtaining the change rate of the detection signal 46
6. The change rate signals 57 from the differentiator 56 and the preset values are compared and the switching signals 58 and 5 are compared.
A high / low monitor 60 that outputs 9 and a gain setting device 6 according to switching signals 58 and 59 from the high / low monitor 60.
Gains 65, 66, 6 output by 1, 62, 63, 64
The present invention relates to a combustion control device for a fuel cell power generation facility, which is provided with switching relays 69 and 70 for switching 7 and 68 and sending them to the multipliers 53 and 54, respectively.

[0019]

The operation of the present invention is as follows.

The temperature detection signal 46 from the temperature detector 45 provided on the combustion gas outlet side of the combustion equipment 4, 9 and the setting device 4
The deviation from the temperature setting signal 48 from 7 is taken by a subtractor 49, and the deviation signal 50 from the subtractor 49 is taken by the proportional-plus-integral controller
2 is converted into a command signal 51, and the command signal 51 is multiplied by the multiplier 5
The flow rate adjusting valve 37 is fed to the flow rate adjusting valve 37 of the auxiliary fuel supply passage 34 connected to the combustion equipment 4, 9 via
Control the opening.

On the other hand, the rate of change of the temperature detection signal 46 from the temperature detector 45 is obtained by the differentiator 56, and the magnitude of the rate of change signal 57 from the differentiator 56 and the preset value is monitored by a high / low monitor. 60, respectively, and based on the result of the comparison, from the high / low monitor 60 to the switching relay 69,
The switching signals 58 and 59 are output to 70, and the gain setter 6
Gains 65, 66, 67 from 1, 62, 63, 64,
68 is switched by switching relays 69 and 70 and sent to the multipliers 53 and 54 to correct the command signal 51.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

The entire fuel cell power generation facility A is the same as that shown in FIG. 2, and the same components as those shown in FIG. 3 are designated by the same reference numerals.

A temperature detector 45 is provided on the outlet side of the combustion equipment such as the catalytic combustor 9 and the reformer 4, and the temperature detection signal 46 from the temperature detector 45 and the temperature setting signal 4 from the setting device 47 are provided.
8 is provided with a subtractor 49 for taking a deviation from the subtracter 49, a proportional-integral controller 52 for converting the deviation signal 50 from the subtractor 49 into a command signal 51, and the command signal 51 is provided with two multipliers 53, 54 and automatic manual switching. The flow rate adjustment valve 37 or the flow rate adjustment valve 38 shown in FIG.

On the other hand, a differentiator 56 for determining the rate of change of the temperature detection signal 46 from the temperature detector 45 is provided, and the magnitude of the rate of change signal 57 from the differentiator 56 and two preset values is set. A high / low monitor 60 for comparing and outputting switching signals 58, 59 is provided, and two gain setting devices 61, 62 and 63, 64 are provided according to the switching signals 58, 59 from the high / low monitor 60. Switching relays 69, 70 for switching the gains 65, 66 and 67, 68 to be output and sending them to the multipliers 52, 53, respectively.
To provide.

The two set values of the high / low monitor 60 are a threshold value when the change rate is positive and a threshold value when the change rate is negative. In addition, the switching relay 69,
70 is normally on the a side, and switching signals 58 and 59 are provided.
When is input, it is switched to the b side.
Further, the gain setting device 6 on the a side of each switching relay 69, 70
2 and 64, the values of the generated gains 66 and 68 are set to 1, and b
The gain setters 61 and 63 on the side, for example, generate the gain 6
The values of 5 and 67 are set to 0.9 (minus 10 percent), 1.1 (plus 10 percent), etc., respectively.

Next, the operation will be described.

The operation of the fuel cell power generation facility A as a whole is the same as that shown in FIG.

The temperature detector 45 detects the temperature of the combustion gas on the outlet side of the catalytic combustor 9, and the subtracter 49 detects the temperature detection signal 46 detected by the temperature detector 45 and the temperature setting signal 48 set by the setter 47. And the deviation signal 50 from the subtractor 49 is converted into a command signal 51 by the proportional-plus-integral controller 52, and the command signal 51 is passed through the two multipliers 53 and 54 and the automatic manual switching device 55, The opening amounts of the flow rate adjusting valve 37 and the flow rate adjusting valve 38 shown in FIG. 2 are adjusted based on the command signal 51 passed through the three multipliers 53 and 54 and the automatic manual switching unit 55, and the supply amounts of the auxiliary fuel 33 and the air 35 are adjusted. To control.

At this time, the switching relays 69 and 70 are normally a.
Since it is on the side, the gains setters 62, 64 send the gains 66, 68 whose value is 1 to the two multipliers 53, 54, and therefore the command signal 51 cannot change its value. It is directly sent to the flow rate adjusting valve 37 and the flow rate adjusting valve 38. The automatic manual switch 55 is on the automatic side.

In addition to the above, the change rate of the temperature detection signal 46 from the temperature detector 45 is obtained by the differentiator 56, and the change rate signal 57 from the differentiator 56 is preset by the high / low monitor 60. Two set values (threshold value)
Compare the size of each with.

When the value of the rate of change signal 57 from the differentiator 56 exceeds the positive threshold value, the high / low monitor 6
0 outputs the switching signal 58 to switch the switching relay 69 to the b side.

When the switching relay 69 is switched to the b side,
The multiplier 53 multiplies the command signal 51 by the gain 65 with the value from the gain setter 61 being 0.9, and the value of the command signal 51 is reduced by that amount.

When the value of the change rate signal 57 from the differentiator 56 falls below the negative threshold value, the high / low monitor 60 outputs the switching signal 59 to switch the switching relay 70 to the b side.

When the switching relay 70 is switched to the b side,
The gain 67 with the value from the gain setter 63 set to 1.1 is multiplied by the command signal 51 by the multiplier 54, and the value of the command signal 51 is increased by that amount.

As a result, when the rate of change of the temperature of the combustion gas increases to the positive side, the flow rate adjusting valve 37 and the flow rate adjusting valve 38 become narrower than in the case of the normal feedback control, and the auxiliary fuel 33 and the air. If the rate of change of the temperature of the combustion gas is increased to the negative side by being corrected in advance so as to suppress the supply amount of 35, the flow rate adjusting valve 37 and the flow rate adjusting valve 38 are opened more than in the case of normal feedback control. Therefore, the amount of the auxiliary fuel 33 and the amount of the air 35 supplied are corrected in advance so that they are increased.
Control response delay is eliminated.

It should be noted that the present invention is not limited to the above-described embodiment, but the switching relay, the gain setting device, the multiplier, and the like can function if they are one set or more, and are limited to two sets. Of course, two or more sets may be provided, and other various modifications may be made without departing from the scope of the invention.

[0039]

As described above, according to the combustion control device for a fuel cell power generation facility of the present invention, the excellent effect of eliminating the response delay of the control for the combustion equipment can be achieved.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention.

FIG. 2 is a general schematic overall view of a fuel cell power generation facility.

FIG. 3 is a system diagram of a conventional example.

[Explanation of symbols]

 4,9 Combustion equipment (reformer 4, catalytic combustor 9) 34 Auxiliary fuel supply path 37 Flow rate regulating valve 45 Temperature detector 46 Temperature detection signal 47 Setting device 48 Temperature setting signal 49 Subtractor 50 Deviation signal 51 Command signal 52 Proportional-integral controller 53, 54 Multiplier 56 Differentiator 57 Change rate signal 58, 59 Switching signal 60 High / Low monitor 61, 62, 63, 64 Gain setter 65, 66, 67, 68 Gain 69, 70 Switching relay A Fuel Battery power generation equipment

Claims (1)

[Claims] 1. A temperature detector 45 is provided on a combustion gas outlet side of combustion devices 4, 9 provided in a fuel cell power generation facility A, and a temperature detection signal 46 detected by the temperature detector 45 and a setting device 4 are provided.
7 is provided with a subtracter 49 for taking a deviation from the temperature setting signal 48 from the No. 7, a proportional-integral controller 52 for converting the deviation signal 50 from the subtractor 49 into a command signal 51, and the command signal 51 is multiplied by a multiplier 53, The temperature detection signal 4 from the temperature detector 45 is configured to be sent to the flow rate adjusting valve 37 of the auxiliary fuel supply path 34 connected to the combustion equipment 4, 9 via 54.
6, a differentiator 56 for obtaining the change rate, a high / low monitor 60 for comparing the change rate signal 57 from the differentiator 56 with a preset value and outputting switching signals 58, 59, the high / low monitor 60,・ Switch signal 5 from low monitor 60
Switching relays 69, 7 for switching the gains 65, 66, 67, 68 output from the gain setters 61, 62, 63, 64 to the multipliers 53, 54 according to 8, 59, respectively.
A combustion control device for a fuel cell power generation facility, wherein 0 is provided.