KR102012365B1 - Fuel cell-Engine hybrid power generation system having a couple of throttle valves for controlling temperature of inlet gas of engine - Google Patents

Abstract

According to an embodiment of the present invention, disclosed is a fuel-engine hybrid power generation system comprising: a fuel cell having an anode as a fuel electrode and a cathode as an air electrode to generate electricity by a chemical reaction between hydrogen and oxygen, and disposed in a hot box maintained at a temperature between 500 degrees Celsius and 100 degrees Celsius; an engine which receives electricity for combustion and combusts to produce electricity; a first pipe transferring an anode off gas discharged from the anode; a second pipe including a first opening/closing valve and supplying outside air; a third pipe including a second open/close valve and supplying external air; a fourth pipe for mixing the anode off gas of the first pipe with the air of the second and third pipes and supplying the engine as a combustion gas; and a control unit for controlling opening amounts of the first and second on/off valves. The air of the third pipe is supplied to the fourth pipe after being heated by receiving thermal energy from the hot box.

Description

Fuel cell-engine hybrid power generation system having a couple of throttle valves for controlling temperature of inlet gas of engine

The present invention relates to a fuel cell-engine hybrid power generation system, and more particularly, to stably operate a fuel cell-engine and to reuse the unutilized energy discharged from the fuel cell in an engine to generate additional power, thereby reusing waste heat of the system. The present invention relates to a fuel cell-engine hybrid power generation system capable of improving system efficiency.

In general, fuel cells are electrochemical devices that convert chemical energy of hydrogen and oxygen directly into electrical energy. Fuel cells have higher efficiency than conventional thermal power generation, which can reduce fuel for power generation and cogeneration, and can use various fuels such as natural gas, city gas, methanol, and waste gas, and thus can replace thermal power generation. It is evaluated as an energy conversion technology. Recently, a fuel cell-engine hybrid power generation system combining an anode off-gas discharged from an anode (fuel electrode) of a high temperature fuel cell and a power generation engine has been proposed.

However, in the case of a fuel cell-engine hybrid power generation system, the anode off-gas of a high-temperature fuel cell is very high, such as 600 to 1000 degrees Celsius, and thus, when it immediately enters the engine, combustion in the engine may not be stable and lead to engine damage. Not only can there be problems with power generation efficiency.

However, the proposed fuel cell-engine hybrid system only presents the concept of integrating the fuel cell and the engine, and considers the problem of how to control the temperature of the gas flowing into the engine under the actual operation as described above. I couldn't. Therefore, there is a need to solve these problems that occur during the actual operation of the fuel cell-engine hybrid system.

Patent Document 1: Korean Unexamined Patent Publication No. 2016-0139492 (published Dec. 7, 2016)

SUMMARY OF THE INVENTION The present invention has been made in view of the above. In the fuel cell-engine hybrid power generation system, the engine intake temperature and intake composition are adjusted to a state suitable for engine combustion, thereby improving the efficiency of the entire power generation system and improving the operating stability of the power generation system. It is an object to provide a battery-engine hybrid power generation system.

According to an embodiment of the present invention, a fuel cell-engine hybrid power generation system includes an anode as an anode and a cathode as an air electrode to generate electricity by a chemical reaction between hydrogen and oxygen, and a temperature between 500 and 1000 degrees Celsius. A fuel cell disposed in a hot box maintained at; An engine that receives electricity for combustion and combusts to produce electricity; A first pipe transferring an anode off gas discharged from the anode; A second pipe including a first opening / closing valve and supplying outside air; A third pipe including a second open / close valve and supplying external air; A fourth pipe for mixing the anode off gas of the first pipe and the air of the second and third pipes to supply the engine as a combustion gas; And a controller for controlling the opening amounts of the first and second on / off valves, wherein the air of the third pipe is heated by receiving thermal energy from the hot box and then supplied to the fourth pipe. A fuel cell-engine hybrid power generation system is disclosed.

According to an embodiment of the present invention, a fuel cell-engine hybrid power generation system, comprising an anode and a cathode, generates electricity by a chemical reaction between hydrogen and oxygen, and is maintained at a temperature between 500 degrees Celsius and 1000 degrees Celsius. A fuel cell disposed in the box; An engine that receives electricity for combustion and combusts to produce electricity; A first pipe transferring an anode off gas discharged from the anode; A second pipe including a first opening / closing valve and supplying outside air; A third pipe including a second open / close valve and supplying external air; A fourth pipe for mixing the anode off gas of the first pipe and the air of the second and third pipes to supply the engine as a combustion gas; And a control unit for controlling the opening amounts of the first and second on / off valves, wherein the air in the third pipe is heated by receiving thermal energy from the engine and is supplied to the fourth pipe. Disclosed is a battery-engine hybrid power generation system.

According to an embodiment of the present invention, by adjusting the engine intake temperature and intake composition to a state suitable for engine combustion in the fuel cell-engine hybrid power generation system, the efficiency of the entire power generation system may be improved and the operational stability of the power generation system may be improved. .

1 is a view for explaining a fuel cell engine hybrid system according to a first embodiment;
2 is a view for explaining a fuel cell-engine hybrid system according to a second embodiment;
3 is a view for explaining a fuel cell-engine hybrid system according to a third embodiment;
4 is a flowchart illustrating a method of controlling an inlet temperature of an engine injection gas according to an embodiment;
5 is a flowchart illustrating a method of controlling an inlet temperature and a composition ratio of an engine injection gas according to an embodiment;
6 is a view for explaining the operation of the first and second on-off valves when the control step (S260) of FIG.

Objects, other objects, features and advantages of the present invention will be readily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art.

In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, the words 'comprise' and / or 'comprising' do not exclude the presence or addition of one or more other components.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In describing the specific embodiments below, various specific details are set forth in order to explain and understand the invention more specifically. However, those skilled in the art to the extent that the present invention can be understood, It can be appreciated that no specific content can be used. In some cases, it is mentioned in advance that parts of the invention which are commonly known in the present invention and which are not related to the invention are not described in order to avoid confusion in describing the present invention.

1 schematically shows a fuel cell-engine hybrid system 100 according to a first embodiment.

Referring to the drawings, the fuel cell-engine hybrid power generation system 100 according to an embodiment includes a hot box 10 including a fuel cell 15 therein and an engine 20 disposed outside the hot box 10. ).

The fuel cell 15 includes an anode and a cathode to generate electricity by a chemical reaction between hydrogen and oxygen. In one embodiment, the fuel cell 15 generates power by an electrochemical reaction of an oxidant (air or oxygen) and a fuel gas (LPG, LNG, methane gas, coal gas, methanol, etc.) including hydrogen or hydrogen, Anode off-gas and cathode off-gas containing unreacted fuel gas are discharged.

The fuel cell 15 receives hot air or oxygen and carbon dioxide from the cathode side and a fuel gas mainly composed of hydrogen on the anode side. The anode produces electricity by the electrochemical reaction of oxygen ions or carbonate ions from the cathode with the fuel gas from the reformer and emits an anode offgas containing water and unreacted fuel gas (such as carbon dioxide). The cathode receives hot air or oxygen to produce carbonate ions and oxygen off-gas by reaction of oxygen ions or oxygen and carbon dioxide. In the illustrated embodiment, the anode offgas is discharged to the outside of the hot box 10 through the first pipe L1, and the cathode offgas is discharged to the outside through the fifth pipe L5.

In one embodiment, the fuel cell 15 may be one of various types of fuel cells that discharge anode off-gas. For example, the fuel cell 15 may include a solid oxide fuel cell (SOFC), a molten carbonate fuel cell (MCFC), a proton exchange membrane fuel cell (PEMFC), and a phosphoric-type fuel cell (PAFC). acid fuel cell), AFC (Alkaline fuel cell) or direct carbon fuel cell (DCFC: Direct Carbon Fuel Cell).

The fuel cell 15 is installed in a high temperature hot box 10 and maintained at a high temperature. In one embodiment hotbox 10 is maintained at a temperature, for example, between 500 degrees Celsius and 1000 degrees Celsius. In one embodiment fuel gas (eg LPG, LNG, methane gas, coal gas, methanol, etc.), water (steam), and air are introduced into the hotbox 10 for the production of electricity in the fuel cell 15. Supplied. As shown, the hot box 10 may further include a reformer 11 therein. The reformer 11 receives fuel gas and water, generates hydrogen, and supplies the hydrogen to the anode of the fuel cell 15.

The fuel gas, water, and air supplied to the hot box 10 must be heated to a high temperature, and for this purpose, for example, the fuel gas, water, and air can be heated by heat exchange with the anode off gas and / or cathode off gas discharged from the fuel cell 15. In the drawing, a path in which fuel gas, water, and air are supplied to the reformer 11 and / or the fuel cell 15 is simply indicated by an arrow, and a specific configuration of the heat exchanger or a path for heat exchange is omitted. However, such a heat exchanger arrangement or heat exchange path inside the hot box 10 may vary depending on the specific embodiment of the fuel cell and is not related to the gist of the present invention. will be.

The engine 20 receives and burns gas for combustion to further produce electricity. In one embodiment, the engine 20 may be supplied with a combustion gas including an anode off gas and air introduced from the outside to generate electricity. In one embodiment, auxiliary fuel may be further supplied to the combustion gas.

The engine 20 may be, for example, at least one of an HCCI engine using a Homogeneous Charge Compression Ignition (HCCI) method, a gasoline engine using a spark ignition method, and a diesel engine using a compression ignition method. In addition, various types of internal combustion engines or external combustion engines such as Stirling engines may be used.

The engine 20 receives the gas for combustion through the pipe L4 to produce electricity and at the same time discharges the exhaust gas through the pipe L6. In one embodiment, the exhaust gas may be introduced into the hot box 10 to exchange heat with at least one of fuel, water, and / or air to supply thermal energy, and then be discharged to the outside. The heat exchange configuration or path of the exhaust gas of the engine 20 may vary depending on the specific embodiment of the fuel cell, and it will be understood that the drawing is briefly indicated by a dotted line in the drawings because it is not a main feature of the present invention.

Now, a pipe and valve structure for supplying combustion gas to the engine 20 will be described. Referring to the drawings, the engine 20 may include first to fourth pipes L1 to L4 to supply the gas for combustion. The first pipe L1 transfers the anode offgas discharged from the anode of the fuel cell 15. The second pipe L2 and the third pipe L3 receive air from the outside and transfer the air to the engine 20 side. Although not shown in the drawings, a blower or a pump for supplying air into the second and third pipes L2 and L3 may be installed.

In one embodiment, the first on-off valve V1 is installed on the path of the second pipe L2, and the second on-off valve V2 is installed on the path of the third pipe L3. Each of the first and second opening valves V1 and V2 is a valve for adjusting the amount of air to be supplied to the engine 20, and each opening amount may be controlled by the controller 30. In one embodiment, each of the first and second on-off valves V1 and V2 may be implemented as a throttle valve.

In one embodiment, the heat exchanger 12 is further installed in the third pipe L3. The heat exchanger 12 may be installed on the path of the third pipe L3 and disposed in the hot box 10. Accordingly, the air supplied from the outside through the third pipe L3 may exchange heat with the high temperature air inside the hot box 10 in the heat exchanger 12 to receive thermal energy.

In this configuration, the anode off gas of the first pipe L1 and the air of the second and third pipes L2 and L3 may be mixed in the fourth pipe L4 and supplied to the engine 20. At this time, air at room temperature is supplied through the second pipe L2, but air heated by the heat exchanger 12 may be supplied through the third pipe L3. That is, by controlling the opening amounts of the first valve V1 of the second pipe L2 and the second valve V2 of the third pipe L3, respectively, the temperature of the air flowing in from the outside can be adjusted, so that the engine 20 Can control the temperature of the combustion gas supplied to.

In one embodiment may include a temperature sensor 31 for temperature control of the combustion gas. Preferably, the temperature sensor 31 may be installed close to the inlet side of the engine 20, that is, on the path of the fourth pipe L4 to measure the temperature of the combustion gas supplied to the engine 20. have. The temperature measurement value measured by the temperature sensor 31 may be transmitted to the controller 30 in real time or periodically or aperiodically.

In an alternative embodiment it may further include a gas sensor 32 to control the combustion gas in accordance with the composition ratio of the combustion gas. In the present specification, the 'gas sensor' 32 is a generic expression of any device capable of measuring the composition ratio of the gas for combustion. For example, the gas sensor 32 may refer to a sensor disposed on the path of the fourth pipe L4 or a sensor installed in the exhaust pipe L6 of the engine 20. As another example, to measure the composition ratio of the combustion gas, at least a part of the engine intake temperature and pressure, the RPM of the engine output shaft, the input fuel flow rate of the fuel cell-engine hybrid system, and the amount of current generated by the fuel cell are measured. The gas composition ratio for combustion may be calculated from this, and in this case, the gas sensor 32 may mean comprehensively measuring devices such as a pressure sensor, a temperature sensor, an RPM sensor, and the like that measure such temperature, pressure, RPM, and the like. In addition, the composition ratio of the gas for combustion may be calculated by the fuel flow rate measured on the system and the operating conditions of the fuel cell, and other known methods of measuring or calculating the gas composition ratio may be used. Although not shown in the drawings, in another alternative embodiment, the fuel cell-engine hybrid system of the present invention may further include a flow rate sensor for measuring the flow rate of the combustion gas.

The controller 30 may control the opening amounts of the first on / off valve V1 and the second on / off valve V2 based on the measured values of the temperature sensor 31 and / or the gas sensor 32, respectively.

For example, if the temperature T measured by the temperature sensor 31 is lower than the preset reference temperature range, the controller 30 reduces the opening amount of the first valve V1 and the opening amount of the second valve V2. By increasing the temperature of the air to be supplied to the combustion gas can be increased. On the contrary, when the measured temperature T of the temperature sensor 31 is higher than the reference temperature range, the open air amount of the first valve V1 may be increased and the open air amount of the second valve V2 may be decreased to lower the air temperature. . At this time, the reference temperature range is the most efficient temperature range for the operation of the engine 20 and may be, for example, any temperature range between 300 and 400 degrees Celsius.

In another embodiment, the controller 30 may control the opening amount of the first valve V1 and the opening amount of the second valve V2 based on the fuel composition ratio G measured by the gas sensor 32. .

For example, if the composition ratio of the anode off-gas to the air in the combustion gas is higher than the reference range, the controller 30 supplies more air to adjust the composition ratio to an appropriate range. For example, the controller 30 may increase the combined opening amounts of the first and second valves V1 and V2 to introduce more air than the current total air inflow through the second and third pipes L2 and L3. Can be. On the contrary, for example, when the composition ratio of the anode offgas to air in the combustion gas is lower than the reference range, the inflow of air is reduced to increase the composition ratio. That is, the total opening amount of the first and second valves V1 and V2 may be reduced so as to introduce less air than the current total air inflow rate through the first and second pipes L2 and L3. In another alternative embodiment, the controller 30 may control the opening amounts of the first and second valves V1 and V2 in consideration of both the temperature and the gas composition ratio. A more specific control operation of the controller 30 will be described later with reference to FIGS. 4 to 6.

As described above, according to the fuel cell-engine hybrid system 100 according to the first embodiment, air is introduced into two different paths through two separate pipes L2 and L3, but is introduced through one pipe L3. Since the air is heated by heat exchange with the hot air of the hot box 10 and then supplied as a combustion gas, the air has at least the following technical advantages.

First, the engine 20 can be easily controlled to increase the engine efficiency. In a typical fuel cell-engine hybrid system, the engine 20 operates by using the anode off-gas of the fuel cell 15 as a fuel, and the amount of non-combustible components (for example, H 2 O and CO 2, etc.) is high in the anode off-gas. Efficient combustion in the engine requires a higher engine intake temperature compared to the engines that are normally operated. Moreover, combustion phenomena occurring in the engine 20 vary greatly in combustion efficiency according to the engine intake temperature.

However, in the fuel cell-engine hybrid system, the combustion component of the combustion gas supplied to the engine 20 is received from the anode off gas of the fuel cell, but the anode off gas is changed by the operation of the fuel cell 15. Therefore, it depends on the operation of the fuel cell 15. That is, there is a problem in that the combustion gas to be supplied to the engine cannot be freely controlled from the engine 20 when viewed from the engine 20 side. Conventionally, in order to solve this problem, a method of adjusting the amount of air supplied from the outside, removing moisture from the anode off gas, or cooling the temperature of the anode off gas was used, but it was not able to sufficiently control the gas for combustion. However, according to the fuel cell-engine hybrid system of the present invention described above, each opening amount of the pair of valves V1 and V2 is individually controlled, but the air of one pipe L3 is exchanged with the hot air of the hot box. Since it can be supplied in a wider temperature range and gas composition ratio range than in the prior art, the engine control can be efficiently and easily performed.

Second, according to the fuel cell-engine hybrid system of the present invention, it is possible to improve the system efficiency through the waste heat recovery of the hot box 10. According to the exemplary embodiment of the present invention, the air introduced through the third pipe L3 is heated by receiving thermal energy from the hot box 10. In general, the inside of the hot box 10 is maintained at a high temperature of more than 500 degrees Celsius, which causes a large amount of waste heat is lost to the discharge from the hot box to the outside. However, in the system of the present invention, at least a part of the path of the pipe L3 is disposed to pass through the inside of the hot box 10 so that the air of the pipe L3 is configured to receive the high temperature heat energy inside the hot box 10. As described above, not only can the temperature control of the combustion air be facilitated, but also the waste heat of the hot box 10 is reused, thereby increasing the overall system efficiency of the fuel cell-engine hybrid system.

A fuel cell engine hybrid system 200 according to a second embodiment will now be described with reference to FIG. 2. The system 200 of the second embodiment includes a first reformer 11, a second reformer 14, and a fuel cell 15, an engine 20, a controller 30, and a temperature disposed within the hot box 10. A sensor 31, a gas sensor 32, and a plurality of piping L1 to L6 are included, and these components are almost the same as or similar to the system 100 of the first embodiment of FIG. However, the fuel cell-engine hybrid system 200 according to the second embodiment has a difference in that the hot box 10 further includes at least a second heat exchanger 13 and a second reformer 14.

The second heat exchanger 13 is installed on the path of the first pipe L1 for transporting the anode off-gas. The second reformer 14 may be installed at the rear end of the first reformer 11, and may further extract hydrogen by further reforming the gas transferred from the first reformer 11. At this time, a part of the thermal energy of the anode off-gas may be supplied to the second reformer 14 by the second heat exchanger 13.

According to the system 200 of the second embodiment described above, since the high temperature heat energy of the anode off-gas can be supplied to the reformer 14, there is an advantage of reusing the heat of the anode off-gas. In addition, in this case, since the anode off-gas takes part of the thermal energy to the second reformer 14, the temperature of the anode off-gas supplied to the fourth pipe L4 is lower than that of the embodiment of FIG. 1. However, according to the present invention, since the air supplied through the third pipe L3 may receive thermal energy through the heat exchanger 12 in the hot box 10, the first on-off valve V1 and the second on-off valve V2. By appropriately adjusting the opening amount of the combustion gas can be controlled in the same or similar temperature range as in FIG.

3 shows a fuel cell engine hybrid system 300 according to a third embodiment. Referring to the drawings, the system 300 according to the third embodiment includes a reformer 11 and a fuel cell 15 disposed in a hot box 10, an engine 20, a controller 30, and a temperature sensor 31. ), A gas sensor 32, and a plurality of pipes L1 to L6 are almost the same as or similar to the system 100 of the first embodiment of FIG. 1, and thus detailed descriptions thereof are omitted. However, the fuel cell-engine hybrid system 300 according to the third embodiment includes the heat exchanger 40 for heat exchange between the engine 20 and the air supplied from the outside. There is a difference.

According to the system 300 of the third embodiment, the air supplied from the outside through the third pipe L3 is supplied with the waste heat of the engine 20 through the heat exchanger 40 and heated to the fourth pipe L4. Transferred. In one embodiment, the heat exchanger 40 includes a heat transfer medium path that circulates between the engine 20 and the heat exchanger 40. The heat exchanger 40 is configured such that heat exchange occurs between the third pipe L3 for transferring air and the heat transfer medium path, so that the air in the third pipe L3 receives waste heat of the engine 20 through the heat transfer medium. Can be supplied and heated.

According to the third embodiment described above, unlike the first or second embodiment, air of the third pipe L3 receives heat energy from the engine 20 rather than the hot box 10. However, unlike the conventional system in which the high temperature thermal energy generated by the engine 20 is discarded as waste heat, in the present invention, since the waste heat of the engine is used for heating the air, the fuel cell-engine hybrid system is similar to the system 100 of the first embodiment. Can have the same effect of increasing the overall overall system efficiency.

4 to 6, a method of controlling a temperature and / or a composition ratio of a combustion gas injected into an engine according to an exemplary embodiment will be described.

4 is an exemplary flowchart for controlling an inlet temperature of an engine combustion gas (hereinafter referred to as "injection gas") according to one embodiment. Referring to the figure, the temperature sensor 31 measures the temperature of the fourth pipe (L4) in real time (or periodically or aperiodic) (S110). The temperature sensor 31 transmits the measured temperature value to the controller 30, and the controller 30 determines whether the measured temperature T is within a preset reference range (S120). This reference range may be any temperature range between 300 degrees Celsius and 400 degrees Celsius as the temperature at which combustion may occur efficiently in the engine 20.

If the measured temperature T is higher than the preset reference temperature range, the controller 30 may increase the opening amount of the first valve V1 and reduce the opening amount of the second valve V2 (S131). ). At this time, in one embodiment, the total opening amounts of the first valve V1 and the second valve V2 may be kept the same as the existing total opening amount, thus transferring the total flow rate of the air supplied to the combustion gas. It remains the same as, but can only reduce the temperature.

On the contrary, when the measured temperature T is lower than the preset reference temperature range, the controller 30 may reduce the opening amount of the first valve V1 and increase the opening amount of the second valve V2 (S133). Even in this case, the total opening amount of the first valve V1 and the second valve V2 may be maintained to be the same as the existing total opening amount, and thus the temperature of the air may be increased while maintaining the same amount of the total supply of air. .

If the measured temperature T is within the preset reference temperature range, the controller 30 may maintain the open amounts of the first and second valves V1 and V2 without changing them (S132).

5 is an exemplary flowchart illustrating a method of controlling an inlet temperature and a gas characteristic of an engine injection gas according to an exemplary embodiment. Referring to the drawing, first, in step S210, the controller 30 obtains the temperature T and the fuel composition ratio G from a measuring device such as the temperature sensor 31 or the gas sensor 32.

The controller 30 determines whether the temperature T is within a preset reference range (S220), and when the temperature T is higher than the reference range, increases the opening amount of the first valve V1 and decreases the opening amount of the second valve V2. A first control signal for generating is generated (S231). However, the controller 30 further generates a second control signal according to the fuel composition ratio G in addition to the control signal.

For example, the controller 30 determines whether the fuel composition ratio G is within a preset reference range in step S240 (S240). For example, if the composition ratio of the anode off gas to the air in the combustion gas is higher than the reference range, the control unit 30 to introduce more air than the current total air inflow through the second and third pipes (L2, L3). A second control signal for increasing the sum of the opening amounts of the first and second valves is generated (S251). Accordingly, the controller 30 controls the first control signal (that is, the opening amount control signals of the first and second valves V1 and V2) and the second control signal (that is, the control signal for increasing or decreasing the total opening amount). The opening degree of the 1st and 2nd valves V1 and V2 is controlled according to the combination of (S260). For example, in the above example, the total opening amount may be increased, but the opening amount of the first valve V1 may be increased and the opening amount of the second valve V2 may be reduced.

As another example, when the temperature T is lower than the reference range and the composition ratio G is higher than the reference range, the controller 30 reduces the opening amount of the first valve V1 and the opening amount of the second valve V2. After generating the first control signal to increase the (S233) and the second control signal to increase the overall opening amount (S251) and the opening amount of the valve (V1, V2) in accordance with the first and second control signal, respectively Can be controlled. Therefore, according to the above-described embodiment, both the increase and decrease of the opening amount and the increase and decrease of the opening amount of each valve V1 and V2 can be controlled according to the temperature T and the composition ratio G of the engine combustion gas. The combustion gas can be more precisely controlled to improve engine combustion efficiency.

On the other hand, in the case of increasing or decreasing the total opening amount in the above (S251, S253), the upper limit flow rate and the lower limit flow rate of the combustion gas can be set in advance so that the total flow rate of the combustion gas is not too large or too small. It may be desirable to increase or decrease the total opening amount.

FIG. 6 illustrates an exemplary control operation of the first and second on-off valves when the control step S260 of FIG. 5 is executed. As described above, the increase and decrease of the total opening amount and the opening and closing amounts of the valves V1 and V2 are controlled according to the temperature T and the composition ratio G of the engine combustion gas, but the temperature T and the composition ratio G are controlled. It may be more effective to preferentially control either the first valve V1 or the second valve V2 according to the current state of.

For example, when the temperature T is higher than the preset reference range and the fuel composition ratio G is higher than the preset reference range, the opening amount of the first valve V1 is increased and the opening amount of the second valve V2 is increased. Control to increase the total opening amount. However, in this case, since the total opening amount needs to be increased, the opening amount of the first valve V1 may be increased first (S261). That is, if the opening amount of the second valve V2 is maintained in the same state as the conventional one, the total opening amount increases when the opening amount of the first valve V1 is increased, so that at least one of the temperature T and the component ratio G First, the opening amounts of the valves V1 and V2 may be controlled with respect to an element that can satisfy the reference range and then fail to satisfy the reference range.
If the temperature T of the combustion gas is higher than the preset reference range and the fuel composition ratio G is lower than the preset reference range, the opening amount of the second valve V2 is first reduced to decrease the temperature T or the component ratio ( First, at least one of G) may be satisfied within a reference range, and then an opening amount of each valve V1 and V2 may be controlled with respect to an element that does not satisfy the reference range (S262).
Similarly, if the temperature T of the combustion gas is lower than the preset reference range and the fuel composition ratio G is higher than the preset reference range, the opening amount of the second valve V2 is first increased and then each valve ( The opening amounts of V1 and V2 can be controlled (S263).

As shown in FIG. 6, when one of the first valve V1 and the second valve V2 is preferentially controlled first according to the current state of the temperature T and the composition ratio G, the first valve V1 and the first valve are controlled. By simultaneously varying the opening amount of the two valves V2, there is an advantage in that the temperature and the composition ratio of the combustion gas can be prevented from changing unintentionally.

As will be appreciated by those skilled in the art to which the present invention pertains, various modifications and variations are possible from the description of this specification. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

10: hotbox
15: fuel cell
20: engine
30: control unit
100, 200, 300: fuel cell-engine hybrid system

Claims (10)

As a fuel cell engine hybrid power generation system,
A fuel cell 15 having an anode and a cathode to generate electricity by a chemical reaction of hydrogen and oxygen, and disposed in a hot box 10 maintained at a temperature between 500 and 1000 degrees Celsius;
An engine 20 that receives the combustion gas and burns the gas to produce electricity;
A first pipe (L1) for transferring an anode off gas discharged from the anode;
A second pipe (L2) including a first open / close valve and supplying external air to the anode off gas;
A third pipe (L3) including a second open / close valve and supplying external air to the anode off gas;
A fourth pipe (L4) for mixing the anode off gas of the first pipe and the air of the second and third pipes and supplying the engine as a combustion gas;
A temperature sensor 31 for measuring the temperature of the combustion gas of the fourth pipe L4; And
And a control unit 30 for controlling the opening amounts of the first and second on / off valves.
The air of the third pipe (L3) is supplied to the fourth pipe (L4) after being heated by receiving heat energy from the air in the hot box,
When the temperature of the combustion gas is lower than a preset reference temperature range, the controller decreases the opening amount of the first on-off valve, increases the opening amount of the second on-off valve, and when the temperature is higher than the reference temperature range. A fuel cell engine hybrid power generation system, characterized in that for controlling the temperature of the combustion gas by increasing the opening amount of the first on-off valve and decreasing the opening amount of the second on-off valve. The method of claim 1,
Further provided on the path of the third pipe (L3) and further comprises a heat exchanger 12 disposed in the hot box 10,
Fuel cell-engine hybrid power generation system, characterized in that the air of the third pipe is heat exchanged with the air in the hot box in the heat exchanger (12) to receive thermal energy. delete The method of claim 1,
The control unit obtains a composition ratio of the gas for combustion in the fourth pipe L4 and controls the opening amount of the first on-off valve and the opening amount of the second on-off valve based on the temperature and the composition ratio. Fuel cell-engine hybrid power generation system. The method of claim 4, wherein the control unit,
When the composition ratio of the anode off gas to the air in the combustion gas is higher than the reference range, the first and second opening and closing to enter more air than the current total air inflow through the second and third pipes (L2, L3) Increase the opening amount of the valve,
When the composition ratio is lower than the reference range, the total opening amount of the first and second open / close valves may be reduced so as to introduce less air than the current total air inflow through the first and second pipes L2 and L3. A fuel cell engine hybrid power generation system, characterized in that for controlling. The method of claim 4, wherein the control unit,
When the temperature of the combustion gas is higher than the preset first reference range and the composition ratio of the anode off gas to air in the combustion gas is lower than the preset second reference range, the opening amount of the second opening / closing valve is first reduced and the After controlling the opening amount of the first on-off valve (S262),
When the temperature is lower than the first reference range and the composition ratio is higher than the second reference range, the opening amount of the second on-off valve is first increased and then the opening amount of the first on-off valve is controlled (S263). Fuel cell-engine hybrid power generation system. As a fuel cell engine hybrid power generation system,
A fuel cell 15 having an anode and a cathode to generate electricity by a chemical reaction of hydrogen and oxygen, and disposed in a hot box 10 maintained at a temperature between 500 and 1000 degrees Celsius;
An engine 20 that receives the combustion gas and burns the gas to produce electricity;
A first pipe (L1) for transferring an anode off gas discharged from the anode;
A second pipe (L2) including a first open / close valve and supplying external air to the anode off gas;
A third pipe (L3) including a second open / close valve and supplying external air to the anode off gas;
A fourth pipe (L4) for mixing the anode off gas of the first pipe and the air of the second and third pipes and supplying the engine as a combustion gas;
A temperature sensor 31 for measuring the temperature of the combustion gas of the fourth pipe L4; And
And a control unit 30 for controlling the opening amounts of the first and second on / off valves.
The air of the third pipe (L3) is supplied to the fourth pipe (L4) after being heated by receiving heat energy from the engine,
When the temperature of the combustion gas is lower than a preset reference temperature range, the controller decreases the opening amount of the first on-off valve, increases the opening amount of the second on-off valve, and when the temperature is higher than the reference temperature range. A fuel cell engine hybrid power generation system, characterized in that for controlling the temperature of the combustion gas by increasing the opening amount of the first on-off valve and decreasing the opening amount of the second on-off valve. The method of claim 7, wherein
A heat exchanger (40) for exchanging heat energy between the air of the third pipe (L3) and the engine; And
And a heat transfer medium path circulating between the engine and the heat exchanger 40.
And the air of the third pipe receives heat energy of the engine through the heat transfer medium. The method of claim 7, wherein
Further comprising a gas sensor 32 for measuring the composition ratio of the combustion gas of the fourth pipe (L4),
And the control unit controls the opening amount of the first on-off valve and the opening amount of the second on-off valve on the basis of the temperature and the composition ratio. The method of claim 9, wherein the control unit,
When the temperature of the combustion gas is higher than the preset first reference range and the composition ratio of the anode off gas to air in the combustion gas is lower than the preset second reference range, the opening amount of the second opening / closing valve is first reduced and the After controlling the opening amount of the first on-off valve (S262),
When the temperature is lower than the first reference range and the composition ratio is higher than the second reference range, the opening amount of the second on-off valve is first increased and then the opening amount of the first on-off valve is controlled (S263). Fuel cell-engine hybrid power generation system.

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