JPH06140063A - Pipe temperature raising method and device in fuel cell power generation equipment - Google Patents

Abstract

PURPOSE:To provide a method and a device to shorten a temperature raising time of a pipe containing a reformer when a fuel cell is started. CONSTITUTION:A reformer 10, a fuel cell 20, a heat exchanger 50 to heat combustion gas of the reformer by anode exhaust gas, a gas cooler 30 and a steam separator 32 to separate moisture in the anode exhaust gas and an anode blower 40 to supply the anode exhaust gas to a combustion chamber of the reformer, are provided. An anode gas line 2 and an anode exhaust gas line 3 are communicated with each other by bypassing the fuel cell, and a combustion gas line 5 and a fuel gas supply line 1 are communicated with each other by bypassing the reformer, and bypass the gas cooler and the steam separator so as not to pass through the gas cooler and the steam separator. A closed loop is constituted of these bypass lines and existing lines or pipelines, and nitrogen gas is circulated in the closed loop while being heated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for raising the temperature of a pipe of a fuel cell power generation facility, and more particularly, to a temperature rise of a pipe including a reforming pipe of a reformer at the time of starting the fuel cell power generation facility. A method and apparatus for reducing time.

[0002]

2. Description of the Related Art Molten carbonate fuel cells have characteristics that conventional power generators do not have, such as high efficiency and little impact on the environment, and they are attracting attention as a power generation system following hydropower, thermal power, and nuclear power. Is currently being researched and developed all over the world. Particularly in a power generation facility using a molten carbonate fuel cell using natural gas as a fuel, a reformer 10 for reforming a fuel gas 1 such as natural gas into an anode gas 2 containing hydrogen as shown in FIG. A fuel cell 20 for generating power from an anode gas and a cathode gas containing oxygen is generally provided,
The anode gas 2 produced by the reformer 10 is supplied to the fuel cell 20, and most of the anode gas 2 (for example, 80
%), And is supplied to the combustion chamber 10a of the reformer 10 as anode exhaust gas.

Before the anode exhaust gas is supplied to the reformer 10, it is passed through a gas cooler 30 and a steam separator 32 for condensing and separating the water in the anode exhaust gas, and the gas from which the water 8 has been separated. Is pumped by the anode blower 40 and supplied as combustion gas to the combustion chamber 10a of the reformer 10 through the heat exchanger 50. In the heat exchanger 50, heat is exchanged between the high temperature anode exhaust gas immediately after passing through the fuel cell 20 and the combustion gas pumped by the anode blower 40.

In the reformer 10, combustible components (hydrogen, carbon monoxide, methane, etc.) in the combustion gas are combusted in the combustion chamber 10a with the air 7 supplied separately, and in the reforming chamber 10b by the high temperature combustion gas. The reforming pipe 10c is heated to reform the fuel gas passing through the reforming pipe 10c. The flue gas discharged from the reforming chamber 10b is merged with the cathode gas for the fuel cell, and the necessary carbon dioxide is supplied to the cathode side of the fuel cell 20. A part of the cathode gas reacts in the fuel cell 20 and is then discharged to the outside of the system.

In such a power generation facility, a chemical reaction is carried out by the residual gas remaining in the fuel cell when the operation is stopped. Is filled with nitrogen gas (N2 gas). Also, when the operation of the power generation equipment is started, it is necessary to circulate while heating the nitrogen gas to raise the temperature of the piping and the like. This is because when the operation of the power generation equipment is started with the pipes and the like being cooled, the reforming steam contained in the fuel gas is cooled in the reforming pipe 10c of the reformer 10 to become water droplets, and these water droplets are modified. This is because the reforming catalyst in the quality tube 10c is deteriorated and it is necessary to prevent this.

Therefore, in conventional power generation equipment, in order to raise the temperature of the piping and the like while circulating the nitrogen gas filled in the piping when the operation is stopped, the nitrogen gas is circulated in addition to the existing piping. Necessary piping was installed to circulate nitrogen gas. That is, the bypass line 4 that connects the anode gas line 2 and the anode exhaust gas line 3 and does not pass the fuel cell 20, the combustion gas line 5 that enters the combustion chamber 10a of the reformer 10, and the combustion gas are modified. Pawn 10
The reforming pipe 10c of the reformer 10-anode gas line 2-bypass line 4-anode exhaust gas line 3 is provided with a bypass line 6 that communicates with the fuel gas supply line 1 that supplies the reforming pipe 10c. -Heat exchanger 50-Gas cooler 30-Steam water separator 32-Anode blower 40-Heat exchanger 50-Combustion gas line 5-Bypass line 6-Fuel gas supply line 1-Reformer 10 closed loop path It was formed and nitrogen gas was circulated by the anode blower 40. Although the anode exhaust gas is used as a combustion gas that is burned in the combustion chamber of the reformer, for convenience of description, it enters the anode blower 40 from the fuel cell 20 via the gas cooler 30 and the steam separator 32. To the anode exhaust gas, and its path is called the anode exhaust gas line 3, the gas from the anode blower 40 to the combustion chamber of the reformer is called the combustion gas, and its path is called the combustion gas line 5.

The nitrogen gas circulating in such a circulation path is heated in the reformer 10, passes through the heat exchanger 50, and then is cooled when passing through the gas cooler 30 and the steam separator 32. When passing through the heat exchanger 50 again, heat is exchanged with the high temperature nitrogen gas upstream of the gas cooler 30 and the steam separator 32 to be heated, and then the combustion gas line 5 and the bypass line 6. Returned to the reforming pipe 10c of the reformer 10 via the fuel gas supply line 1. The reformer 10
In the above, the fuel is burned in the combustion chamber 10a to heat the nitrogen gas passing through the reforming tube 10c.

[0008]

However, in the above-described power generation equipment, the high-temperature nitrogen gas that has passed through the anode exhaust gas line 3 passes through the heat exchanger 50 and then the gas cooler 30 and the steam separator. Since it is passed through 32, it is cooled, and even if such nitrogen gas is supplied to the combustion gas supply line 1 via the heat exchanger 50, since it is once cooled, the temperature rising rate of the pipe is increased. There was a problem that it took a long time to make the power generation equipment operate normally.

The present invention was created to solve such a problem. That is, the present invention focuses on the fact that the nitrogen gas circulating in the closed loop path contains no water vapor, and the heated nitrogen gas without passing through the gas cooler and the steam separator is unnecessarily cooled. The purpose of this is to reduce the time required for normal operation of the power generation equipment by increasing the temperature of the piping at a high speed at the time of starting the power generation equipment.

[0010]

According to the present invention, a reformer for reforming a fuel gas into an anode gas containing hydrogen, a fuel cell for generating power from the anode gas and a cathode gas containing oxygen, and a fuel A heat exchanger that heats the combustion gas immediately before the combustion chamber of the reformer by exchanging heat with the high-temperature anode exhaust gas that has left the battery, and gas cooling that separates the water content of the anode exhaust gas cooled by the heat exchanger. Fuel cell power generation including a gas cooler and a steam separator, and an anode blower for supplying the anode exhaust gas from which water has been separated by the gas cooler and the steam separator to the combustion chamber of the reformer as a combustion gas A method for raising the temperature of piping of equipment, wherein the fuel cell is bypassed to connect the anode gas line and the anode exhaust gas line, and the reformer is bypassed to connect the combustion gas line and the fuel gas supply line. , The bypass line between the anode exhaust gas line upstream of the gas cooler and the anode exhaust gas line downstream of the steam blower and upstream of the anode blower is communicated by bypassing the bypass cooler and the steam water separator. And a line or piping for forming a closed loop, and circulating nitrogen gas while heating the nitrogen gas in the closed loop.

Furthermore, according to the present invention, a reformer for reforming a fuel gas into an anode gas containing hydrogen, a fuel cell for generating electricity from the anode gas and a cathode gas containing oxygen, and a fuel cell are provided. A heat exchanger that heats the combustion gas by exchanging heat with the high-temperature anode exhaust gas, a gas cooler and a steam separator that separate the water content of the anode exhaust gas cooled by the heat exchanger, and the gas cooler and A fuel cell power generation equipment pipe heating device comprising: an anode blower for supplying, as a combustion gas, an anode exhaust gas from which water has been separated by a steam separator to a combustion chamber of a reformer. A bypass line that bypasses the battery and connects the anode gas line and the anode exhaust gas line, and a bypass line that bypasses the reformer and connects the combustion gas line and the fuel gas supply line, A bypass line that communicates with the anode exhaust gas line upstream of the gas cooler by bypassing the gas cooler and the steam cooler and the anode exhaust gas line downstream of the steam blower and upstream of the anode blower, There is provided a temperature raising device for piping of a fuel cell power generation facility, characterized in that a closed loop is formed by these bypass lines and existing lines or piping.

[0012]

According to the present invention, the gas cooler and the steam separator for communicating the anode exhaust gas line upstream of the gas cooler and the anode exhaust gas line downstream of the steam blower and upstream of the anode blower. Since the bypass line is provided, the nitrogen gas is not unnecessarily cooled without passing through the gas cooler and the steam separator in the heating and circulation of the nitrogen gas at the start of the operation of the power generation equipment.

Therefore, the temperature of the pipes including the reforming pipes of the reformer can be raised at high speed by circulating the nitrogen gas, and the time required for normal operation of the power generation equipment can be shortened. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. In the drawings, devices common to the conventional power generation equipment are designated by the same reference numerals and used. FIG. 1 is an overall configuration diagram showing a power generation facility for carrying out the method according to the present invention. Since the normal operation of the power generation equipment is not different from the normal operation described in the power generation equipment shown as the above-mentioned conventional example, the description thereof will be omitted, and the nitrogen gas circulation at the start of operation of the power generation equipment will be described in detail. .

Reference numeral 11a is a shut-off valve arranged at a position downstream of the branch point of the anode gas line 3 with the bypass line 4 (position on the fuel cell side), and 11b is downstream of the fuel cell of the anode gas line 3. A cutoff valve provided, 12 is a cutoff valve provided in the middle of the bypass line 4,
These shutoff valves are controlled so as to switch between the normal operation and the start of the operation of the power generation equipment.

Reference numeral 13 is a shut-off valve disposed at a position downstream of the branch point of the combustion gas line 5 with the bypass line 6 (position on the reformer side), and 14 is in the middle of the bypass line 6. These shutoff valves are provided, and these shutoff valves are controlled so as to switch between the normal operation and the start of operation of the power generation equipment. A bypass line 15 connects the anode exhaust gas line 3 upstream of the gas cooler 30 and the anode exhaust gas line downstream of the steam separator 32 and upstream of the anode blower 40.

Reference numeral 16 is a shut-off valve disposed at a position downstream of the branch point of the anode exhaust gas line 4 with the bypass line 15 (position on the gas cooler 30 side), and 17 is in the middle of the bypass line 15. These shutoff valves are provided, and these shutoff valves are controlled so as to switch between the normal operation and the start of operation of the power generation equipment. Note that these shutoff valves are arranged immediately after the positions where the bypass lines are branched and are controlled so as to be switched depending on the operation mode of the power generation equipment. However, the present invention is not limited to this, and there are two directions at the branch points of the bypass lines. It is also possible to use a switching valve that can be switched to, and to switch depending on the operation mode of the power generation equipment.

In the power generation equipment as described above, at the start of its operation, the nitrogen gas is circulated as follows. First, each of the shutoff valves provided on the bypass line side is opened, and the shutoff valves located at positions near the combustion chamber side of the fuel cell, the gas cooler, and the reformer from the branch points are closed. That is, the shutoff valves 11a, 1a provided before and after the fuel cell 20 in the anode gas line 2
1b is closed and the shut-off valve 12 provided in the fuel cell bypass line 4 is opened, whereby the nitrogen gas flows through the fuel cell bypass line 4 without going to the fuel cell.

In addition, the shutoff valve 16 provided immediately before the gas cooler 30 in the anode exhaust gas line 4 is closed, and the shutoff valve 17 provided in the bypass line 15 of the gas cooler 30 and the steam separator 32 is opened. As a result, the nitrogen gas does not go to the gas cooler 30 and the steam / water separator fuel cell 32, but flows through the bypass line 15 of the gas cooler 30 and the steam / water separator 32.

Further, in the combustion gas line 5, the shutoff valve 13 provided immediately before the combustion chamber 10a of the reformer 10 is closed, and the bypass line 6 of the combustion chamber 10a of the reformer 10 is closed.
The shutoff valve 14 provided in the reformer 10 is opened, so that the nitrogen gas does not go to the combustion chamber 10a of the reformer 10 and flows through the bypass line 6 of the combustion chamber 10a of the reformer 10.

Then, the nitrogen gas constitutes a closed loop path by the bypass line and the existing line or piping as described below, and circulates in the closed loop path. That is, the reforming tube 10c of the reformer 10-anode gas line 2-bypass line 4-anode exhaust gas line 3-
Heat exchanger 50-Bypass line 15-Anode blower 4
0-Heat exchanger 50-Combustion gas line 5-Bypass line 6-Fuel gas supply line 1-Reformer 10 reformer 10
A closed loop path of c is formed, and the nitrogen gas is circulated by the anode blower 40.

By the way, in such a closed loop path, first, the nitrogen gas is heated in the reforming pipe 10c of the reformer 10 by the combustion of the fuel in the combustion chamber 10a, and the heated nitrogen gas is the fuel. After passing through the bypass line 4 of the battery, the heat exchanger 50 is supplied with the heat exchanger 5.
At 0, heat exchange is performed with nitrogen gas in the combustion gas line 5 to be described later, and the heat flows through the gas cooler 30 and the bypass line 15 of the steam separator 32. At this time, since the nitrogen gas does not flow to the gas cooler 30 and the steam separator 32, it is not unnecessarily cooled.

Next, the gas cooler 30 and the steam separator 32
Of the nitrogen gas flowing through the bypass line 15 of the fuel cell is pumped by the anode blower 40, passes through the combustion gas line 5 and the heat exchanger 50, and passes through the bypass line 6 of the combustion chamber 10a of the reformer 10 and the fuel gas supply line. Merged into 1.

The nitrogen gas heated in the reforming pipe 10c of the reformer 10 is gradually cooled as it flows through each line, but is further cooled by the heat exchanger 50 downstream of the anode blower 40 by a heat source (of the reformer). Since heat exchange is performed with the nitrogen gas in the portion close to the reforming pipe), it is heated again, and the temperature of the pipe and the like can be efficiently raised. The nitrogen gas joined to the fuel gas supply line 1 is again supplied to the reforming pipe 10c of the reformer 10, where it is heated and then circulates in the closed loop path.

[0025]

Therefore, according to the present invention, the gas cooler and the gas communicating with the anode exhaust gas line upstream of the gas cooler and the anode exhaust gas line downstream of the steam-water separator and upstream of the anode blower are connected. Since the bypass line of the water separator is provided, the nitrogen gas is not unnecessarily cooled without passing through the gas cooler and the steam separator during the heating and circulation of the nitrogen gas at the start of the operation of the power generation facility, and therefore The temperature of the pipes including the reforming pipes of the reformer can be raised at high speed by circulating the nitrogen gas, and thus the time required for normal operation of the power generation equipment can be shortened.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a power generation facility for carrying out a method according to the present invention.

FIG. 2 is an overall configuration diagram showing a conventional power generation facility.

[Explanation of symbols]

 1 Fuel Supply Line 2 Anode Gas Line 3 Anode Exhaust Gas Line 4 Bypass Line (Fuel Cell) 5 Combustion Gas Line 6 Bypass Line (Reformer) 7 Air 8 Moisture (Drain) 10 Reformer 10a Combustion Chamber 10b Reforming Chamber 10c Reforming tube 11a, 11b, 13, 14, 16, 17 Shut-off valve 15 Bypass line (gas cooler and steam separator) 20 Fuel cell 30 Gas cooler 32 Steam separator 40 Anode blower 50 Heat exchanger

Front page continuation (72) Inventor Bunro Hashimoto 3-16 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Ltd. Toyosu General Office

Claims (2)

[Claims] 1. A reformer for reforming a fuel gas into an anode gas containing hydrogen, a fuel cell for generating power from the anode gas and a cathode gas containing oxygen, and a high-temperature anode exhaust gas and heat discharged from the fuel cell. A heat exchanger for exchanging and heating the combustion gas supplied to the combustion chamber of the reformer, a gas cooler and a steam separator for separating the water content of the anode exhaust gas cooled by the heat exchanger, and the gas. A method of raising the temperature of a pipe of a fuel cell power generation facility, comprising: an anode blower for supplying the anode exhaust gas from which water has been separated by a cooler and a steam separator to a combustion chamber of a reformer as a combustion gas. , Bypassing the fuel cell to connect the anode gas line and the anode exhaust gas line, bypassing the reformer to connect the combustion gas line and the fuel gas supply line,
Bypassing the gas cooler and the steam / water separator, the anode exhaust gas line upstream of the gas cooler and the anode exhaust gas line downstream of the steam / water separator and upstream of the anode blower are connected, and these bypass lines and the existing A method for raising the temperature of a pipe of a fuel cell power generation facility, characterized in that a closed loop is formed by the line or the pipe and the nitrogen gas is circulated while heating in the closed loop. 2. A reformer for reforming a fuel gas into an anode gas containing hydrogen, a fuel cell for generating power from the anode gas and a cathode gas containing oxygen, and a high-temperature anode exhaust gas and heat discharged from the fuel cell. A heat exchanger for exchanging and heating the combustion gas, a gas cooler and a steam separator for separating the water content of the anode exhaust gas cooled by the heat exchanger, and a water content for the gas cooler and the steam separator. And a anode blower for supplying the separated anode exhaust gas to a combustion chamber of a reformer as a combustion gas, and a temperature raising device for piping of a fuel cell power generation facility, wherein the fuel cell bypasses the fuel cell. A bypass line that connects the gas line and the anode exhaust gas line, a bypass line that bypasses the reformer and connects the combustion gas line and the fuel gas supply line, a gas cooler and moisture content. A bypass line that bypasses the separator and connects the anode exhaust gas line upstream of the gas cooler and the anode exhaust gas line downstream of the steam blower upstream of the anode blower is provided. A temperature raising device for piping of a fuel cell power generation facility, characterized in that a closed loop is constituted by a line or piping.