JPH0637281B2 - Fuel reformer - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a fuel reforming apparatus, and more particularly to a gas reforming device for releasing gas into the atmosphere so that the internal pressure of the reforming tube is higher than the external pressure by a predetermined value or more. The present invention relates to a fuel reformer equipped with a discharge gas flow rate control means for controlling a flow rate.

[Technical background of the invention]

FIG. 1 shows a configuration example of a conventional fuel reformer. In the figure, reference numeral 1 denotes a fuel reformer, which is provided with a reforming pipe 2 and a combustor 3 for burning exhaust gas from a fuel cell (not shown) as a load therein. Reference numeral 4 is a combustion chamber in the fuel reformer 1. Inside the reforming tube 2,
A reaction gas in which a raw fuel such as natural gas and steam for reforming are mixed is introduced through control valves 5 and 6, respectively. This reaction gas is heated by the combustor 3 in the fuel chamber 4 to be reformed into a reformed gas containing hydrogen as a main component, and further passes through the carbon monoxide shift converter 7 through the reforming pipe 2 to generate a reaction product therein. The carbon monoxide is converted into carbon dioxide, which is harmless to the fuel cell. Thereafter, the reformed gas is condensed by removing excess water vapor introduced for the reforming reaction in the condenser 8 and guided to the fuel cell through the control valve 9.

On the other hand, a control valve 10 is provided on the upstream side of the control valve 9 so that the reformed gas is discharged into the atmosphere through the control valve 10 during the stop operation. Further, the reformed gas led to the fuel cell consumes hydrogen due to an electrochemical reaction through the cell and is exhausted, and after passing through some heat exchangers and condensers, the reformed gas of the fuel reformer 1 is discharged. Control valve 11 in combustor 3
It is used as a heat source for the reforming together with the fuel air supplied through.

In such a fuel reformer, the control valves 5, 6, 9 and 11 are closed at the time of the stop operation of the device, and the gas contained in the reforming pipe 2 system of the device is released into the atmosphere by the control valve 10. I am trying to do it. In this case, the control of the control valve 10 is controlled by the reforming pipe 2
While monitoring the gas pressure detected by the pressure detector 12 provided at the outlet of the condenser 8 which is the outlet line of the, the pressure is gradually reduced in accordance with the step-down command.

[Problems of background technology]

By the way, in the above-described internal gas release control of the fuel reformer, when the pressure reduction rate of the released gas is too fast and the amount of released gas becomes excessive, the inside of the reforming pipe 2 of the fuel reformer 1 is increased. The pressure may be lower than the external pressure of the combustion chamber 4. When the internal pressure of the reforming pipe 2 becomes lower than the external pressure under high temperature, there is a problem that the buckling phenomenon of the reforming pipe 2 occurs and the pipe is broken.

[Object of the Invention]

The present invention has been made to solve the above problems, and its purpose is to control the internal pressure of the reforming tube to be higher than the external pressure by controlling the gas release even in a transient state such as the stop operation of the apparatus. It is an object of the present invention to provide a fuel reforming device capable of preventing the reforming pipe from being broken so as to prevent deterioration and improve reliability and prolong life.

[Outline of Invention]

In order to achieve the above object, in the present invention, while introducing a raw material gas in which a raw fuel and water vapor are mixed into the inside of the reforming pipe, the heating gas is passed through the outside of the reforming pipe,
The raw material gas is reformed into a reformed gas, and the reformed gas is supplied from the reforming pipe outlet line to the load through the first control valve for the operation of the apparatus main body and the second for the stop of the apparatus main body. In the fuel reforming device configured to release the air into the atmosphere via the control valve of the reforming pipe, the pressure difference between the internal pressure of the reforming pipe and the external pressure, and the internal pressure of the reforming pipe are used. Emission gas flow rate control means for controlling the opening of the second control valve is provided so that the internal pressure becomes higher than the external pressure by a predetermined value or more.

Example of Invention

 An embodiment of the present invention shown in the drawings will be described below.

FIG. 2 shows an example of the configuration of the fuel reforming apparatus according to the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described here.

In the figure, 13 is a differential pressure detector that detects the differential pressure between the internal pressure and the external pressure of the reforming pipe 2 and outputs the differential pressure signal ΔP when the internal pressure is higher than the external pressure.

Further, 14 is a differential pressure signal ΔP from the differential pressure detector 13.
And a pressure signal Px from the pressure detector 12 as an input, which provides a valve control signal Vc to the control valve 10 in a mode described later. The differential pressure detector 13 and the differential pressure controller 14 constitute a reforming pipe differential pressure control means.

FIG. 3 shows a detailed configuration example of the differential pressure controller 14. In the figure, 14-1 is the pressure detector 12
From the pressure signal Px from the reference pressure signal Pxs
And a first comparator for comparing and, and outputs a first valve control signal Vc1 in the valve opening direction in accordance with the deviation. Further, 14-2 is a differential pressure signal ΔP from the differential pressure detector 13.
And a reference differential pressure signal .DELTA.Ps, which outputs a second valve control signal Vc2 in the valve closing direction according to the deviation only when the comparison result is .DELTA.P <.DELTA.Ps. Further, 14-3 is a combiner which receives the respective control signals Vc1 and Vc2 from the respective comparators 14-1 and 14-2, and normally combines the signal Vc1 and the signal Vc2 as a correction signal into the signal Vc1. These signals are output as the valve control signal Vc.

In the fuel reformer having such a structure, the control valves 5, 6, and 9.11.
The gas contained in the system is released into the atmosphere by the control valve 10. In this case, the control valve 10 obtains according to the deviation between the pressure signal Px from the pressure detector 12 and the reference pressure signal Pxs which is the pressure reduction command, and the first comparator 14 of the differential pressure controller 14
It is controlled in the opening direction by the first valve control signal Vc1 from -1, and the pressure of the released gas gradually decreases as described above.

On the other hand, in this process, if the pressure reduction rate of the released gas becomes too fast and the amount of released gas becomes excessive as described above, and the internal pressure of the reforming pipe 2 becomes lower than the external pressure, this is caused by the differential pressure detector 1
3 and the differential pressure signal ΔP is detected by the differential pressure controller 1
Given to 4. Then, the second pressure in the differential pressure controller 14
Of the comparator 14-2 and the reference differential pressure signal ΔP.
Ps is compared, and when ΔP <ΔPs, the second valve control signal Vc2 is output according to the deviation. Then, in the combiner 14-3, the second valve control signal Vc2 is combined with the first valve control signal Vc1 as a correction signal, and the control valve 10 is controlled in the closing direction by the combined valve control signal Vc. As a result, the release of gas is suppressed, and it becomes possible to prevent the internal pressure of the reforming pipe 2 from further decreasing.

As described above, in the fuel reformer of this embodiment,
The differential pressure ΔP between the internal pressure and the external pressure of the reforming pipe 2 is detected by the differential pressure detector 13, and the internal pressure of the reforming pipe 2 is adjusted while the differential pressure signal ΔP and the pressure signal Px of the released gas are coordinated. Since the reforming pipe differential pressure control means for controlling the gas release is provided so that the pressure becomes higher than the external pressure by a fixed value ΔPxs or more, the reforming pipe 2 is provided even in the transient state such as the stop operation of the apparatus. It is possible to improve the reliability and prolong the life of the reforming pipe 2 by reliably preventing the internal pressure thereof from lowering than the external pressure and preventing the pipe from being broken due to the buckling phenomenon of the reforming pipe 2 under high temperature conditions. It is a thing.

〔The invention's effect〕

As described above, according to the present invention, based on the internal pressure of the reforming pipe and the external pressure, and the internal pressure of the quality control pipe, the internal pressure of the reforming pipe is higher than the external pressure. Since the reforming pipe differential pressure control means for controlling the amount of reforming gas discharged from the reforming pipe outlet line into the atmosphere so as to be higher than the value is provided, even in a transient state such as when the device is stopped. Provided is a fuel reformer capable of preventing the reforming pipe from being broken by controlling the gas discharge so that the internal pressure of the reforming pipe does not fall below the external pressure, and improving reliability and extending the life of the reforming pipe. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional fuel reformer, FIG. 2 is a block diagram showing an embodiment of the fuel reformer of the present invention, and FIG. 3 is an example of a differential pressure controller in the same embodiment. It is a block diagram shown. 1 ... Fuel reformer, 2 ... Reformer tube, 3 ... Combustor, 4 ...
… Combustion chambers, 5, 6, 9, 10, 11 …… Control valves, 7 ……
Carbon monoxide shifter, 8 ... Condenser, 12 ... Pressure detector, 13 ... Differential pressure detector, 14 ... Differential pressure controller, 14-
1, 14-2 ... Comparator, 14-3 ... Synthesizer.

Claims (1)

[Claims] 1. A raw material gas, which is a mixture of raw fuel and steam, is introduced into the reforming pipe, and a heating gas is passed through the outside of the reforming pipe to convert the raw material gas into reformed gas. The quality of the reformed gas is supplied from the reforming pipe outlet line to the load through the first control valve that opens when the apparatus body is in operation, and also through the second control valve that opens when the apparatus body is stopped. In a fuel reforming device adapted to release air into the atmosphere, the internal pressure of the reforming pipe is determined based on the internal pressure of the reforming pipe and the pressure difference between the internal pressure and the external pressure of the reforming pipe. Is provided with a discharge gas flow rate control means for controlling the opening degree of the second control valve so as to be higher than the external pressure by a predetermined value or more.