JPS6271172A - Power generation plant of phosphoric acid-type fuel cell - Google Patents

Abstract

PURPOSE:To improve efficiency of power generation, by introducing waste air, which includes steam, into a heat exchanger not through a steam separator, and then introducing it into a water-treatment device through the steam separator and the like. CONSTITUTION:Waste air including steam obtained from an air hole 6 in a cell is directly introduced, without it either steam-separated or cooled as it is under high temperature, into a heat exchanger 13, which is installed between a reformer 2 and a carbon monoxide transformer 3, so that it can be heat- exchanged for high-temperature reformed gas obtained from the reformer 2. Thereafter, it is supplied into a turbine 11 through an auxiliary combustion room 10 or a combustion part in the reformer 2. Hence, the waste air passing through a line 39 is increased in flow rate and raised in temperature. Therefore, the amount of high-temperature combustion gas produced by auxiliary combustion becomes reduced, and the auxiliary fuel can be saved together with efficiency of power generation improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to improvements in phosphoric acid fuel cell power plants.

[Prior art]

Conventionally, there are two technologies for phosphoric acid fuel cell power generation plants. One is a technology that effectively utilizes all the steam generated within the system, thereby increasing the power generation efficiency of the fuel cell itself. and the other one is
This is a method in which a part of the steam generated within the system is effectively used as a heat source in a heating device outside the system. In the former case,
Although it has the advantage of improving power generation efficiency itself, it has the disadvantage of being inferior in terms of total energy recovery efficiency obtained from the entire plant.On the other hand, in the latter case, the total energy recovery efficiency is lower than in the former case. However, it has the disadvantage of being inferior in power generation efficiency. Therefore, in the latter technology, improving the power generation efficiency is a technical issue.

FIG. 3 shows a flow sheet for a typical example of a conventional power generation plant that effectively utilizes a portion of the steam generated within the system as a heat source for a heating device outside the system. In this traditional flow? Condensed water (cooling water) is circulated between the Li pond cooling unit 8 and the steam drum 9 through lines 44 and 42, and a part of the steam from the steam drum 9 is extracted outside the system through the line 45, and the heating device After effectively using the water as a heat source, the water is circulated as condensed water through the line 47 to the water treatment device 4. 1! The waste air containing steam from the air electrode 6 of the pond 5 is sent to a cooler 15 and then to a steam/moisture extractor 14 where the steam is condensed, and the resulting condensed water is passed through a line 40 to a water treatment device. 4, and on the other hand, waste air not containing steam is introduced into a heat exchanger 13 disposed between the reformer 2 and the carbon monoxide shift converter 3, and then introduced into the auxiliary combustor 10. It is said that

In the case of this conventional method, a part of the steam obtained from the steam drum is extracted outside the system and effectively used as a heat source for a heating device outside the system. The steam-containing waste air that has come out of the waste air is immediately introduced into the steam/water separator S14, where the steam contained in the waste air is condensed into condensed water, which is then introduced into the steam drum 9 via the water treatment device 4. are doing. Therefore, in conventional power generation plants that recover the thermal energy generated within the system as steam and effectively use it as a heat source for heating equipment outside the system, the power generation efficiency is inevitably low, as shown in Figure 3. For the plant shown in .

Its power generation efficiency is about 39.5%.

〔the purpose〕

The present invention can be applied to a conventional power plant as shown in FIG. The purpose is to provide a means to increase the electrical rate.

〔composition〕

According to the present invention, there is provided a reformer with a combustion section that reacts fuel and steam to generate hydrogen, and a carbon monoxide shift converter that converts carbon monoxide contained in the gas produced from the reformer into carbon dioxide. a heat exchanger disposed between the reformer and the carbon monoxide shift converter, an air electrode, a fuel electrode, and a cooler for reacting hydrogen and oxygen to obtain electrical energy. A phosphoric acid fuel cell and an auxiliary combustor that burns auxiliary fuel.

a turbine that expands heated gas to obtain mechanical energy; an air compressor driven by the turbine;
Piping that sends compressed air from the air compressor to the air electrode of the battery, the combustion section of the reformer, and the auxiliary combustor, and the high-fuel gas from the fuel electrode of the battery to the combustion section of the reformer. The pipe to send and M! A! and piping for sending combustion gas from the combustion chamber to the auxiliary combustor.

It is equipped with piping for sending combustion gas from the auxiliary combustor to the turbine, and further includes a steam drum for sending condensed water to the cooler of the battery and receiving steam from the cooling 8) 4, and for treating the condensed water. , a water treatment device that sends treated water to the steam drum, a pipe that sends a part of the steam obtained from the steam drum to a heating device outside the system, and a pipe that sends another part of the steam to the reformer. A phosphoric acid fuel cell power generation plant comprising: the reformer and the carbon monoxide shift converter, in which waste air containing steam obtained from the air electrode of the cell is transferred to the reformer and the carbon monoxide shift converter without passing through the steam/water molecule a device; and a cooler for condensing and separating the steam contained in the exhaust gas from the turbine; A steam separator, piping that sends exhaust gas from the turbine to the steam separator via the cooler, and piping that sends condensed water from the steam water separator to the water treatment device. A phosphoric acid fuel cell power generation plant is provided.

Next, the present invention will be explained in detail with reference to the drawings. In addition, in the reference numerals shown in FIGS. 1 to 3, the same reference numerals have the same meanings.

In FIG. 1, fuel (hydrocarbon such as natural gas or naphtha) passes through a line (piping) 20 to a carbon oxide shift converter 3.
It is introduced into the desulfurizer 91 together with the fuel gas (hydrogen-containing gas) returned from the The product from the desulfurizer 1 is sent to the combustion section reformer 2 along with steam returned from the steam drum 9 through line 46. In this reformer 2, the following reaction occurs and hydrogen is produced.

CnHm+ nH2O→ (n+1/2m)I12+nC○ (1
)ncO+nH2O-Snil 2+nCO7(II)
This main reaction (1) is a high-temperature endothermic reaction, and the heat required for one reaction is supplied by combustion of fuel in a combustion section provided in the reformer. In this case, high fuel gas from the fuel electrode 7 of the battery 5 is used as the fuel, and the air necessary for combustion is made up of waste air from the air electrode 6 of the battery 5 and air from the air compressor 12. used.

The reformed gas from the reformer 2 is passed through the line 22 and the heat exchanger 81 (1
3 and line 23 to the carbon monoxide shift converter 3, where the carbon monoxide contained in the reformed gas is converted into carbon dioxide and hydrogen. - A part of the gas from the carbon oxide shift converter 3 is fed through the inlet 25 to the desulfurizer I, and the remainder is sent through line 26 to its anode 7 as fuel gas for the cell 5.

The fuel 11 tank 5 is a pressurized type (phosphoric acid fuel cell) that uses phosphoric acid as an electrolyte, and in this cell, hydrogen contained in the fuel gas supplied as described above and the air compressor 12 Water is produced by reacting with oxygen contained in the air supplied to the air electrode 6 through lines 31 and 34, and the reaction energy at that time is extracted as electrical energy.

High fuel gas from fuel electrode 7 passes through line 35.

The waste air from the air electrode 6 is sent to the combustion section of the reformer 2, while the waste air from the air electrode 6 contains the steam generated from the hydrogen and oxygen, which is not subjected to water separation (in the reformer). After being sent to the heat exchanger 13 disposed between the carbon monoxide shift converter 3 and the carbon monoxide shift converter 3, it passes through the line 39 to the auxiliary combustor lO and the line 49 to the combustion boundary section of the reformer 2. each will be sent.

In the auxiliary combustor 10, waste air is supplied as described above, auxiliary fuel is supplied through the line 27, and combustion gas from the combustion section of the reformer 2 is further supplied through the line 36. A portion of the air from the air compressor 12 is also supplied through line 32 where combustion of the auxiliary fuel takes place. The heated gas obtained from the auxiliary combustor 10 is supplied to the turbine 11 and expanded there. The turbine is rotated by the expansion energy of the gas at this time, and the air compressor 12 is driven by the rotational force of this turbine. Ru. Air compressor 12 draws air through line 30 and forces compressed air into line 31.

Exhaust gas from the turbine 11 passes through lines 29 and 51 and further passes through a cooler 15 before passing through line 52 and being sent to a steam separator 14 . In the steam-water separator 14, steam contained in the turbine exhaust gas is separated as condensed water, which is sent to the water treatment device 4 through a line 40, while gas components are discharged through a line 50. Ru. The condensed water that has been purified by the water treatment device 4 is transferred to the line 4.
1 and sent to the steam drum 9.

The condensed water sent to the steam drum 9 is sent to the cooler 8 of the battery 5 through a line 44 to cool the battery to a predetermined temperature, and is also converted to steam.
2 and circulated to the steam drum 9. Mechi-11
The steam in the drum 9 is extracted through a line 43, and a part of it is extracted to the outside of the yarn through a line 45 and is used as a heat source for a heating device installed outside the system, and the condensation generated by its use is Water is circulated to the water treatment device 4 through line 47. Further, another part of the steam extracted through line 43 is sent to reformer 2 through line 46.

In the present invention, the use of the auxiliary combustor 10 is not necessarily required and can be omitted.

That is, as shown in FIG. 2, waste air containing steam from the heat exchanger 13 is directly introduced into the combustion section of the reformer through line 39, and combustion gas from the combustion section is introduced into line 2.
8 directly into the turbine 11. In this case, in FIG.
An amount of fuel corresponding to the auxiliary fuel supplied is added as an increment to the fuel passing through line 20.

〔effect〕

In the present invention, as described above, ? ! ! The waste air containing steam obtained from the air electrode 6 of the pond was placed between the reformer 2 and the carbon monoxide shift converter 3 without being separated into water and water, and without being cooled and kept at a high temperature. The gas is directly introduced into the heat exchanger 13 to exchange heat with the high temperature reformed gas obtained from the reformer 2, and then supplied to the turbine 11 via the auxiliary combustor IO or the combustion section of the reformer 2. Therefore, the waste air passing through line 39.

The flow rate is increased and the temperature is also higher than in the conventional case shown in FIG. Therefore, compared to the conventional case shown in Figure 3, the amount of high-temperature combustion gas generated by auxiliary combustion is smaller, auxiliary fuel is saved, and as a result, the power generation efficiency per unit of consumed fuel is improved. .

Furthermore, in the present invention, since the high-temperature exhaust gas from the turbine 11 is treated in the low moisture #i unit 14, in the case of the present invention, steam generated by combustion of fuel is also recovered as condensed water. It has the advantage of

In the power generation plant of the present invention, the total energy recovery rate per fuel used, that is, the total energy recovered as electrical energy by the battery and thermal energy of the steam sent to the heating device outside the system, is about 74%, Furthermore, the rate of recovery as electrical energy (power generation efficiency) is approximately 42.1%. In contrast, in the conventional case, the total energy recovered as electrical energy from batteries and thermal energy from steam is about 69%.
Furthermore, the rate at which the electricity is recovered as electrical energy (power generation efficiency) is approximately 39.5%. Therefore, according to the invention:
In a phosphoric acid fuel cell power generation plant that effectively utilizes a portion of the steam generated within the system outside the system, the power generation efficiency, which was previously considered difficult, can be improved by simple means, and this has great industrial significance. .

[Brief explanation of drawings]

1 and 3 show flow sheets of a phosphoric acid fuel cell power generation plant, with FIG. 1 showing the present invention and FIG. 3 showing a conventional example. FIG. 2 shows a partially modified view of FIG. 1. DESCRIPTION OF SYMBOLS 1... Desulfurizer, 2... Reformer, 3...-carbon oxide shift converter, 4... Water treatment device, 5... Phosphoric acid fuel cell, 6... Air electrode, 7...Fuel electrode, 8...Cooler, 9...Steam drum, ]0...Auxiliary combustor, 1
1...Turbine, 12...Air compressor, 1
3... Heat exchanger, 14... Steam-water separator. Applicant's agent Patent attorney Satoshi Ikeura Akiyuki 1
figure

Claims (2)

[Claims] (1) A reformer with a combustion section that generates hydrogen by reacting fuel and steam, and a carbon monoxide shift converter that converts carbon monoxide contained in the gas produced from the reformer into carbon dioxide; A phosphoric acid type having a heat exchanger disposed between the reformer and the carbon monoxide shift converter, an air electrode, a fuel electrode, and a cooler for reacting hydrogen and oxygen to obtain electrical energy. A fuel cell, an auxiliary combustor that burns auxiliary fuel, a turbine that expands heated gas to obtain mechanical energy, an air compressor that is driven by the turbine, and compressed air from the air compressor that connects the compressed air to the air electrode of the battery. , piping to send waste fuel gas from the fuel electrode of the cell to the combustion part of the reformer, and piping to send the combustion gas from the reformer to the combustion part of the reformer and the auxiliary combustor. A steam drum that includes piping to send to the auxiliary combustor and piping to send combustion gas from the auxiliary combustor to the turbine, and further sends condensed water to the cooler of the battery and receives steam from the cooler. , a water treatment device that processes condensed water and sends the treated water to the steam drum, piping that sends a part of the steam obtained from the steam drum to a heating device outside the system, and a pipe that sends the other part of the steam to a heating device outside the system. A phosphoric acid fuel cell power generation plant equipped with piping to send to a reformer, wherein waste air containing steam obtained from the air electrode of the cell is connected to the reformer without passing through a steam/water separator. The steam contained in the exhaust gas from the turbine is sent to the heat exchanger disposed between the carbon monoxide shift converter, and then to the combustion section of the auxiliary combustion device and the reformer. A cooler and a steam water separator for condensation and separation, piping that sends exhaust gas from the turbine to the steam water separator via the cooler, and condensed water from the steam water separator to the water treatment device. A phosphoric acid fuel cell power generation plant characterized by being equipped with pipes for feeding. (2) a reformer with a combustion section that reacts fuel and steam to generate hydrogen; and a carbon monoxide shift converter that converts carbon monoxide contained in the gas produced from the reformer into carbon dioxide; A phosphoric acid fuel having a heat exchanger disposed between the reformer and a carbon monoxide shift converter, an air electrode, a fuel electrode, and a cooler for reacting hydrogen and oxygen to obtain electrical energy. A battery, a turbine that expands heated gas to obtain mechanical energy, an air compressor driven by the turbine, and piping that sends compressed air from the air compressor to the air electrode of the battery and the combustion section of the reformer. , a pipe that sends waste fuel gas from the fuel electrode of the battery to the combustion section of the reformer, and a pipe that sends the combustion gas from the reformer to the turbine; send it to the cooler of
A steam drum that receives steam from the cooling section, a water treatment device that processes condensed water and sends the treated water to the steam drum, and piping that sends a portion of the steam obtained from the steam drum to a heating device outside the system. A phosphoric acid fuel cell power generation plant comprising: a phosphoric acid fuel cell power generation plant having a pipe for sending another part of the steam to a reformer; The exhaust gas from the turbine is sent to the heat exchanger installed between the reformer and the carbon monoxide shift converter, and then to the combustion section of the reformer. a cooler and a steam water separator that condense and separate the steam contained in the turbine, piping that sends the exhaust gas from the turbine to the steam water separator via the cooler, and a pipe that sends condensed water from the steam water separator A phosphoric acid fuel cell power generation plant characterized by being equipped with piping for sending the water to the water treatment device.