JP3626838B2 - Power generation system for solid oxide fuel cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power generation system for a solid oxide fuel cell (SOFC) that prevents water flow to a fuel cell main body during fuel cell power generation.
[0002]
[Prior art]
FIG. 2 shows an outline of a conventional power generation system for a solid oxide fuel cell.
[0003]
As shown in FIG. 2, gaseous fuel such as water (H ₂ O), carbon monoxide (CO), etc. is provided on the inner tube side of the solid oxide fuel cell (hereinafter referred to as “SOFC”) 1, and the outer tube side thereof. Air is supplied to the air supply pipe 2 and is heated to about 900 ° C. by a heater built in the power generation device 3 to generate power. Further, the fuel required for power generation is supplied from a fuel supply means (not shown) through the fuel supply pipe 4, and the flow rate is controlled by the mass flow controller 5 to be a constant flow rate. On the other hand, air is supplied from an air supply means (not shown) through an air supply pipe 8, and the flow rate is controlled by a mass flow controller 9 so as to be a constant flow rate.
The unreacted fuel and air after power generation are supplied to the chimney 19 and the chimney 20 through the fuel discharge pipe 6 and the air discharge pipe 10, respectively, and discharged to the atmosphere.
[0004]
SOFC power generation is generally operated with a differential pressure between fuel and air (fuel-air) of about +50 mm Aq , but the pressure (P) on the air side is the pressure installed in the air discharge pipe 10 particularly during the pressurization operation. The pressure is adjusted to a predetermined pressure by the adjusting valve 11, and the differential pressure (DP) between the fuel and air is controlled by the differential pressure adjusting valve 7 installed in the fuel discharge pipe 6 so that fuel- air≈50 mm Aq .
[0005]
Although the SOFC 1 generates water vapor by power generation, the water vapor concentration in the fuel-side exhaust gas is particularly high, and if the drain is formed on the upstream side of the differential pressure regulating valve 7, the differential pressure adjustment is affected by the drain, resulting in a differential failure. For this reason, the seal pot 12 is installed on the upstream side of the differential pressure regulating valve 7.
[0006]
High-temperature gas containing unreacted fuel and high-concentration water vapor after power generation enters the seal pot 12 through the fuel discharge pipe 6 and is rapidly cooled by bubbling with water 21 in the seal pot 12 to drain the water vapor. Only gas is discharged from the space 22 above the seal pot 12 to the fuel discharge pipe 6, thereby avoiding malfunction of the differential pressure regulating valve 7 due to drainage.
[0007]
Level switches 13 and 14 are installed in the seal pot 12. When the level switch 14 is operated, the drain discharge valve 18 is opened, and when one of the level switches 13 is operated, the drain discharge valve 18 is closed and the automatic operation is performed. In this system, the drain in the seal pot is discharged. Reference numeral 17 in the drawing shows a level meter, and the valves 15 and 16 are opened so that the water level in the seal pot 12 can be visually confirmed.
[0008]
[Problems to be solved by the invention]
However, in the conventional system, when the differential pressure regulating valve 7 is closed due to the malfunction of the differential pressure regulating valve 7 or the rapid fluctuation of the air pressure, the pressure of the space portion 22 of the seal pot 12 rapidly increases. For this reason, the problem is that the water 21 in the seal pot 12 flows back into the fuel discharge pipe 6 on the power generation device 3 side, flows into the high-temperature SOFC 1, and causes a destruction or performance deterioration of the SOFC 1 due to a steam explosion or the like. There is.
[0009]
[Means for Solving the Problems]
A power generation system for a solid oxide fuel cell of the present invention that solves the above problems
Installed in a power generation apparatus having a solid electrolyte fuel cell having an air supply means and a fuel supply means, and a fuel discharge means for discharging fuel side exhaust gas from the power generation apparatus, and adjusts a differential pressure between fuel and air In a power generation system for a solid oxide fuel cell, comprising: a differential pressure regulating valve; and a seal pot installed upstream of the differential pressure regulating valve to remove water vapor in the fuel side exhaust gas,
The seal pot has a function of bubbling the fuel side exhaust gas into internal water, draining water vapor in the fuel side exhaust gas, and supplying the fuel side exhaust gas from which the water vapor has been removed to the downstream, between the device and the seal pot, characterized in that the drain pot is interposed.
In the power generation system of the solid oxide fuel cell,
The seal pot has a level switch installed therein, and the level switch automatically discharges the internal drain in conjunction with the drain discharge valve, thereby maintaining the internal water level at a predetermined level.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a power generation system of a solid oxide fuel cell according to the present invention will be described.
[0011]
FIG. 1 shows an outline of a power generation system of a solid oxide fuel cell according to an embodiment of the present invention.
As shown in FIG. 1, the power generation system for a solid oxide fuel cell according to the present invention includes a fuel supply pipe 4 for supplying fuel and an air supply pipe 8 for supplying air from an air supply means and a fuel supply means (not shown). A power generation device 3 including a solid oxide fuel cell (SOFC) 1 and a seal pot 12 for removing water vapor in the fuel-side exhaust gas discharged from the power generation device 3 through the fuel discharge pipe 6 to the chimney 19 are provided. In the solid oxide fuel cell power generation system, a drain pot 31 is interposed between the power generation device 3 and the seal pot 12 (on the upstream side of the seal pot 12).
[0012]
The power generator 3 is supplied with gaseous fuel from a fuel supply means (not shown) through a fuel supply pipe 4, while air is supplied from an air supply means (not shown) through an air supply pipe 8. 9 to control the flow rate to be constant. Further, the unreacted fuel and air after power generation are supplied to the chimney 19 and the chimney 20 via the fuel discharge pipe 6 provided with the differential pressure adjustment valve 7 and the air discharge pipe 10 provided with the pressure adjustment valve 11, respectively. Released into the atmosphere.
High-temperature exhaust gas containing unreacted fuel and high-concentration water vapor after power generation enters the seal pot 12 through the fuel discharge pipe 6 and is rapidly cooled by bubbling by the water 21 in the seal pot 12 to drain the water vapor. Only the gas is discharged from the space 22 above the seal pot 12 to the fuel discharge pipe 6, thereby avoiding malfunction of the differential pressure regulating valve 7 due to drainage.
In the present embodiment, a drain pot 31 is further interposed between the power generation device 3 and the seal pot 12 (the upstream side of the seal pot 12), and the seal is caused by a sudden change in air-side pressure. Even when the water 21 in the pot 12 flows backward, the drain pot 31 can absorb the backflow water.
[0013]
The drain pot 31 for collecting the backflow water from the seal pot 12 is connected to the fuel discharge pipes 6 and 6 at the upper part thereof, so that the exhaust gas does not pass through the water 21 like the seal pot 12. ing.
Further, a level meter 32 for measuring the level of the collected water is provided on the side surface of the drain pot 31, and the amount of water inside is visually checked by opening the valves 33 and 34 provided above and below the level meter 32. Can be confirmed.
Further, a drain valve 35 is provided at the lower portion of the drain pot 31, and the water accumulated in the reverse flow can be discharged by opening the drain valve 34.
[0014]
Thus, even if the drain pot 31 is installed on the upstream side of the seal pot 12 and the water 21 in the seal pot 12 flows backward due to a sudden change in the air-side pressure, the drain pot 31 can absorb the backward water. Thus, it is possible to prevent the water from flowing back directly into the SOFC 1 and to prevent the SOFC 1 from being destroyed or deteriorated in performance due to a steam explosion or the like.
Therefore, the SOFC 1 can be protected, and the SOFC 1 can be continuously generated.
[0015]
【The invention's effect】
The present invention has an air supply means and a fuel supply means, and is installed in a power generation apparatus having a solid oxide fuel cell and a fuel discharge means for discharging fuel-side exhaust gas from the power generation apparatus . a differential pressure control valve for adjusting the pressure difference, is installed in the upstream of the difference pressure regulating valve, in the solid electrolyte type fuel cell power generation system that includes a seal pot for removing water vapor in the fuel side exhaust gas, seal pot Has a function of bubbling the fuel-side exhaust gas into the internal water, draining the water vapor in the fuel-side exhaust gas, and supplying the fuel-side exhaust gas from which the water vapor has been removed to the downstream, the power generator and the seal pot Since a drain pot is interposed between them , unlike the conventional case, even if the water in the seal pot flows backward due to abrupt fluctuations in the air side pressure, the drain pot can absorb the backflow water, S It is prevented from flowing back into the FC, to become a factor in the destruction or performance deterioration of the SOFC is prevented by conventional Such steam explosion.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a power generation system of a solid oxide fuel cell according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of a power generation system of a solid oxide fuel cell according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Solid oxide type fuel cell 2 Air supply pipe 3 Power generation device 4 Fuel supply pipe 5 Mass flow controller 6 Fuel discharge pipe 7 Differential pressure adjustment valve 8 Air supply pipe 9 Mass flow controller 10 Air discharge pipe 11 Pressure adjustment valve 12 Seal pots 13 and 14 Level switch 15, 16 Valve 17 Level meter 18 Drain discharge valve 19, 20 Chimney 21 Water 22 Space 31 Drain pot 32 Level meter 33, 34 Valve 35 Drain valve

Claims (2)

A power generation apparatus including a solid oxide fuel cell having air supply means and fuel supply means;
A differential pressure adjusting valve that is installed in a fuel discharge means for discharging the fuel side exhaust gas from the power generation device and adjusts a differential pressure between fuel and air;
In a power generation system for a solid oxide fuel cell, which is installed upstream of the differential pressure regulating valve and includes a seal pot for removing water vapor in the fuel-side exhaust gas,
The seal pot has a function of bubbling the fuel-side exhaust gas into the internal water, draining water vapor in the fuel-side exhaust gas, and supplying the fuel-side exhaust gas from which the water vapor has been removed to the downstream,
A power generation system for a solid oxide fuel cell , wherein a drain pot is interposed between the power generation device and the seal pot. In the power generation system of the solid oxide fuel cell according to claim 1,
The seal pot has a level switch installed therein, and the level switch automatically discharges the internal drain in conjunction with the drain discharge valve to maintain the internal water level at a predetermined level. Type fuel cell power generation system.

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