KR101690638B1 - Hybrid Power Generation System using Fuel Cell and Engine which is capable of Load Following - Google Patents

Abstract

The present invention discloses a fuel cell-engine hybrid power generation system with a load variation type. A fuel cell-engine hybrid power generation system according to an aspect of the present invention includes: a fuel cell that generates electricity by an electrochemical reaction of input oxidizing agent and fuel gas, and discharges an anode off gas; A cooler for outputting a discharge gas as a result of performing at least one of cooling of the anode off-gas and removal of at least a part of moisture from the anode off-gas; A heat exchanger having a first flow path through which the anode offgas flows and a second flow path through which the one exhaust gas flows, the heat exchanging the fluids in the first flow path and the second flow path; A first valve for delivering a discharge gas from the cooler to at least one of a second flow path of the heat exchanger and a bypass of the heat exchanger; A second valve for delivering the anode off-gas to at least one of a first flow path of the heat exchanger and an inflow path of the engine; And a third valve for supplying air to the open city, wherein a discharge gas that is heat-exchanged through a second flow path of the heat exchanger, a discharge gas delivered to a bypass of the heat exchanger, The combustion gas containing at least one of the anode-off gases received is mixed with the air introduced from the third valve, and is supplied to the engine for producing the additional electricity by burning the combustion gas.

Description

[0001] The present invention relates to a hybrid fuel cell system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell-engine hybrid power generation system, and more particularly, to a load cell type fuel cell-engine hybrid power generation system capable of generating electric power using a fuel cell and an engine.

Generally, a fuel cell is an electrochemical device that converts the chemical energy of hydrogen and oxygen directly into electric energy.

Fuel cells are more efficient than conventional thermal power generation, and can save fuel for power generation, can generate cogeneration, and can use various fuels such as natural gas, city gas, methanol, and waste gas. Energy conversion devices.

In addition, NOx and CO2 emissions are considerably lower than coal-fired power plants, and pollution-free operation with low noise is possible, which makes it possible to install in urban areas or buildings.

Examples of the fuel cell include an alkaline fuel cell, a phosphoric acid fuel cell, a polymer electrolyte fuel cell, a solid oxide fuel cell (SOFC), a molten carbonate fuel cell (MCFC) Carbon fuel cell (Direct Carbon Fuel Cell).

Among them, a solid oxide fuel cell (SOFC) and a molten carbonate carbonate fuel cell (MCFC), which operate at a high temperature, can be used for dispersed electric power generating large capacity electricity of several tens kW to MW. Is advantageous to produce additional electricity utilizing the cathode offgas of the cathode. Therefore, recently, a fuel cell-engine hybrid power generation system combining an anode off-gas discharged from a high-temperature fuel cell and a power generation engine has been proposed.

However, in the case of the fuel cell-engine hybrid power generation system, since the anode off-gas of the high-temperature fuel cell is extremely high, that is, about 600 to 1000 degrees Celsius, There is a problem that it may fall.

In addition, the conventional fuel cell-engine hybrid power generation system has not been prepared for the load fluctuation situation.

SUMMARY OF THE INVENTION The present invention has been made in view of the technical background as described above, and it is an object of the present invention to provide a fuel cell engine hybrid power generation system capable of increasing the efficiency of the entire power generation system by adjusting the anode- Fuel cell-engine hybrid power generation system.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

A fuel cell-engine hybrid power generation system according to an aspect of the present invention includes: a fuel cell that generates electricity by an electrochemical reaction of input oxidizing agent and fuel gas, and discharges an anode off gas; A cooler for outputting a discharge gas as a result of performing at least one of cooling of the anode off-gas and removal of at least a part of moisture from the anode off-gas; A heat exchanger having a first flow path through which the anode offgas flows and a second flow path through which the one exhaust gas flows, the heat exchanging the fluids in the first flow path and the second flow path; A first valve for delivering a discharge gas from the cooler to at least one of a second flow path of the heat exchanger and a bypass of the heat exchanger; A second valve for delivering the anode off-gas to at least one of a first flow path of the heat exchanger and an inflow path of the engine; And a third valve for supplying air to the open city, wherein a discharge gas that is heat-exchanged through a second flow path of the heat exchanger, a discharge gas delivered to a bypass of the heat exchanger, The combustion gas containing at least one of the anode-off gases received is mixed with the air introduced from the third valve, and is supplied to the engine for producing the additional electricity by burning the combustion gas.

A fuel cell for generating electricity by electrochemical reaction of input oxidizing agent and fuel gas according to another aspect of the present invention and discharging an anode off gas and a fuel cell for burning the anode off gas to produce additional electricity An anode off gas regulating device for regulating the anode off gas from the fuel cell and supplying the anode off gas to the engine is provided between the engine and the anode of the fuel cell, As a result, a cooler for outputting a working gas; A heat exchanger having a first flow path through which the anode offgas flows and a second flow path through which the one exhaust gas flows, the heat exchanging the fluids in the first flow path and the second flow path; A first valve for delivering a discharge gas from the cooler to at least one of a second flow path of the heat exchanger and a bypass of the heat exchanger; A second valve for delivering the anode off-gas to at least one of a first flow path of the heat exchanger and an inflow path of the engine; And a third valve which is supplied with air to the open city, wherein a discharge gas heat-exchanged through a second flow path of the heat exchanger, a discharge gas delivered to a bypass of the heat exchanger, And the combustion gas, which is at least one of the anode-off gas, is mixed with the air introduced from the third valve and is transmitted to the engine.

According to the present invention, the anode off gas of a high-temperature fuel cell is adjusted to a state suitable for engine combustion, thereby preventing engine failure, improving durability, and improving efficiency of the entire power generation system.

Further, it is possible to cope with the load fluctuation of the power generation system according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the overall configuration of a fuel cell-engine hybrid power generation system according to the present invention; FIG.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a fuel cell engine hybrid power generation system.
3 is a graph showing the relationship between the amount of fuel supplied and the fuel utilization rate according to the present invention.
4 is a flow chart illustrating a method for adjusting the anode off-gas in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, advantages and features of the present invention and methods for accomplishing the same will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, the terms " comprises, " and / or "comprising" refer to the presence or absence of one or more other components, steps, operations, and / Or additions.

Hereinafter, a fuel cell-engine hybrid power generation system according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.

FIG. 1 is a schematic view showing the entire configuration of a fuel cell-engine hybrid power generation system according to an embodiment of the present invention, and FIG. 2 is a schematic view showing an anode off gas of a fuel cell-engine hybrid power generation system according to an embodiment of the present invention. FIG. 3 is a graph showing the relationship between the amount of fuel supplied to the fuel cell and the fuel utilization rate according to the embodiment of the present invention. FIG.

1 and 2, a fuel cell-engine hybrid power generation system 10 according to an embodiment of the present invention includes a fuel cell 110, a heat exchanger 120, a cooler 130, an engine 140, A first valve 151, a second valve 152, a temperature sensing unit 170, a third valve 160, a first mixing pipe 181, a second mixing pipe 182, Hour).

The fuel cell 110 generates electric power by an electrochemical reaction between an oxidant (air or oxygen) and a reformed fuel (hydrogen, syngas, direct carbon, etc.), and an anode off- (Anode off gas) and cathode exhaust gas.

For example, when the fuel cell 110 is an MCFC fuel cell, the fuel cell 110 includes a cathode that receives high temperature air or oxygen and carbon dioxide, and an anode that receives a fuel gas containing hydrogen as a main component. ). The anode produces electricity by electrochemical reaction of oxygen or carbonate ions from the cathode with the fuel gas from the reformer, and discharges the anode off-gas containing water and unreacted fuel (such as carbon dioxide). The cathode receives hot air or oxygen to produce carbonate ions by the reaction of oxygen ions or oxygen with carbon dioxide, and discharges the cathode exhaust gas. Here, the cathode exhaust gas may be used for heat exchange of air or oxygen introduced into the fuel cell 110, and may be heat-recovered by an HRSG (Heat Recovery Steam Generator).

At this time, the fuel cell 110 may be various fuel cells for discharging the anode off gas. For example, the fuel cell 110 may be a solid oxide fuel cell (SOFC), a molten carbonate fuel cell (MCFC), a proton exchange membrane fuel cell (PEMFC), a phosphoric acid -acid fuel cell, an AFC (Alkaline fuel cell), or a direct carbon fuel cell (DCFC). At this time, when a molten carbonate fuel cell (MCFC) is used as the fuel cell 110, it is also possible to re-flow the exhaust gas of the engine 140 into the fuel cell 110 to supply the necessary carbon dioxide from the cathode.

As shown in FIG. 1, a means for supplying high temperature air, oxygen and water, a fuel containing hydrogen (LPG, LNG, methane, coal gas, methanol, byproduct gas, etc.) And a reformer for producing a fuel gas containing a large amount of hydrogen from the reforming gas. The front end configuration of the fuel cell 110 can be variously applied depending on the type of the fuel cell 110 and can be obviously derived from the kind of the applied fuel cell 110 by those skilled in the art. do.

The cooler 130 may cool at least a portion of the anode off gas that has passed through the heat exchanger 120 and cool the anode off gas to lower the temperature or remove moisture from the anode off gas, As a result, one discharge gas is output. For example, the cooler 130 may be of various types such as a water-cooled heat exchanger, an air-cooled heat exchanger, a cooler including a centrifugal water separator, a cooler including an inverted water separator.

However, when the anode off-gas is cooled or the water is removed by the cooler 130, the temperature is lowered, so that the temperature of the work-off gas becomes much lower than that of the anode off-gas. Therefore, the temperature of one exhaust gas is generally equal to or lower than a basic threshold for maintaining the power generation efficiency of the engine 140 at a predetermined value or more and inducing stable combustion, and the temperature of the exhaust gas at the rear end of the cooler 130 .

Here, the basic threshold value means an appropriate temperature of the one exhaust gas before the heat exchange in the heat exchanger 120. For example, the basic threshold is set to a temperature range (lower than the upper limit of the threshold value or higher) that can increase the power generation efficiency of the engine and induce stable combustion after the entire exhaust gas output from the cooler 130 passes through the heat exchanger 120, As shown in FIG.

The heat exchanger 120 is a device for exchanging heat between two fluids. The heat exchanger 120 includes a first flow path through which the anode off-gas flows from the fuel cell 110 and a first flow path through which the first discharge gas, Includes 2 euros. At this time, it is preferable that the first flow path and the second flow path are arranged so as to be mutually heat exchangeable. The heat exchanger 120 is designed to be discharged from the second flow path of the heat exchanger 120, that is, heat exchanged so that the temperature of the combustion gas flowing into the engine 140 is less than a predetermined upper limit value.

The first valve 151 receives the exhaust gas from the cooler 130 and controls the input exhaust gas to flow through the second flow path of the heat exchanger 120 and the heat exchanger 120 under the control of a control unit To the at least one of the bypasses of the < / RTI > Here, the first valve 151 is a valve having a structure capable of branching a flow rate composed of a material capable of withstanding the temperature of one exhaust gas to be input and output. For example, the first valve 151 may be a three-way valve structure or a valve structure connecting two valves.

The second valve 152 receives the anode off-gas from the fuel cell 110 and controls the anode off-gas input according to the control of the controller (not shown) To the at least one of the flow path and the inflow path of the engine 140. Here, the second valve 152 is a valve having a structure capable of branching a flow rate composed of a material capable of withstanding the temperature of the anode off-gas to be input and output (may be 600 to 1000 degrees depending on the type of the fuel cell). For example, the second valve 152 may be a three-way valve structure or a valve structure connecting two valves. A concrete control method of the first and second valves 151 and 152 will be described later with a description of a control unit (not shown).

The first mixing pipe 181 has three input paths for receiving one heat-exchanged exhaust gas, one exhaust gas delivered to the bypass of the heat exchanger 120, and anode off-gas from the second valve 152, And one output path for delivering the combustion gas containing the gas from the two input paths to the engine 140. Here, it is preferable that the output path of the first mixing pipe 181 is formed in such a shape that the gases introduced through the three input paths can be mixed well.

The temperature sensing unit 170 is provided between the third valve 160 and the first mixing pipe 181 to sense the temperature of the combustion gas before being mixed with the air flowing into the third valve 160, And transmits the sensed temperature to a control unit (not shown). For example, the temperature sensing unit 170 may be a sensor installed in a pipe and may be a removable temperature sensor attached to a pipe or the like.

The temperature sensing unit 170 is provided between the cooler 130 and the first valve 151 or between the first valve 151 and the inflow path of the second flow path of the heat exchanger 120, It can also sense the temperature. Alternatively, one or more temperature sensing units 170 may be provided to sense temperatures of the combustion gas and the working gas. In the following description, the temperature sensing unit 170 senses the temperature of the combustion gas for convenience of explanation.

The third valve 160 controls the amount of air supplied to the engine 140. The amount of opening of the third valve 160 is controlled by a control unit (not shown), and air (oxygen or the like) To the mixing pipe (182). For example, the third valve 160 may be a throttle valve.

The second mixing pipe 181 has two input paths for receiving the combustion gas mixed by the first mixing pipe 181 and the air from the third valve 160, And one output path for delivering gas and air to engine 140. Here, it is preferable that the output path of the second mixing pipe 182 is provided in such a shape that the gases introduced through the two input paths can be mixed well. The second mixing pipe 182 may be replaced with a throttle body.

The engine 140 receives the combustion gas from the output path of the first mixing pipe 181 and burns it to produce additional electricity. At this time, air and auxiliary fuel introduced into the third valve 160 may be further supplied to the engine 140, and the engine 140 may further utilize the air and the auxiliary fuel, which are introduced together with the combustion gas, .

Here, the engine 140 may be 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. However, when the HCCI engine is used as the engine 140, the maximum combustion temperature can be lowered and the effect of reducing NOx and PM emissions can be obtained.

At this time, even if the engine 140 is a premixed compression ignition engine, it may include an ignition plug therein. The engine 140 may also include other ignition means that perform the function of an ignition plug rather than an ignition plug.

The engine 140 may be combusted in a premixed compression ignition manner depending on the state of the combustion gas, and the combustion gas may be ignited by using another ignition means such as an ignition plug. For example, when the engine 140 generates electricity by using only the combustion gas, it is burned by the premixed compression ignition method. When the engine 140 generates electricity by supplying the supplementary fuel, the engine 140 uses the spark plug or other ignition means, You may.

Here, a component such as an HRSG, a reformer, a heat exchanger, or the like may be further provided at the rear end of the engine 140, such as to recover heat from the exhaust gas of the engine 140. Since the peripheral configuration of the engine 140 can be clearly derived from the kind of the engine 140 by those skilled in the art, a detailed description thereof will be omitted.

The control unit (not shown) controls the first, second, and third valves 151, 152, and 160 according to at least one of the sensed temperature of the combustion gas and the load variation (supply fuel amount and fuel utilization rate fluctuation). Specifically, the controller (not shown) performs control at the time of control, change ② ① load condition according to the sensed temperature. Hereinafter, the respective functions of the control unit (not shown) are separately described.

① Flow control according to sensing temperature

The control unit controls at least one of the first valve 151, the second valve 152 and the third valve 160 according to the sensed temperature every predetermined period to adjust the temperature of the combustion gas to the engine efficiency It can be adjusted within a predetermined allowable range. For example, the control unit (not shown) may be a microcontroller supplying an electrical signal capable of adjusting the transfer ratio between the two output paths of the first and second valves 151 and 152. In this case, the first and second valves 151 and 152 may be valves that can control a discharge gas delivery ratio by an electrical signal.

Basically, the control unit (not shown) operates the first valve 151 in such a manner that the entire exhaust gas from the cooler 130 is transferred to the second flow path of the heat exchanger 120, and the temperature of the combustion gas The first valve 151 is operated in such a manner that at least a part of the combustion gas is transferred to the bypass passage of the heat exchanger 120 in order to lower the temperature of the combustion gas.

Specifically, the control unit (not shown) confirms the sensing temperature of the combustion gas sensed by the temperature sensing unit 170 while transmitting the entire exhaust gas to the heat exchanger 120. At this time, if the sensed temperature is higher than the upper limit value, the controller (not shown) controls the first valve 151 to transfer at least a part of the exhaust gas from the cooler 130 to the bypass passage of the heat exchanger 120, The temperature of the gas can be lowered.

In this case, even if the temperature of one exhaust gas from the cooler 130 is too low to transfer the entire exhaust gas from the cooler 130 to the second flow path of the heat exchanger 120, If it is not equal to or greater than the threshold value, the controller (not shown) can no longer control the temperature of the combustion gas by the first valve 151, so that the second valve 152 can be adjusted as follows.

 Here, the threshold value and the upper limit value refer to the temperature range of the combustion gas in which stable combustion can occur while increasing the engine efficiency. In order to prevent the engine from being damaged, the upper limit value may be set lower than the minimum temperature (< 0 > C) of the gas that may flow into the engine 140 and damage it.

The control unit (not shown) basically allows the entire anode off gas from the fuel cell 110 to be transferred to the heat exchanger 120. When the temperature of the combustion gas by the first valve 151 is no longer acceptable The second valve 152 may be adjusted to adjust the temperature of the combustion gas.

The control unit (not shown) controls the second valve 152 to increase the amount of the anode off-gas delivered to the inflow path of the engine 140 to increase the temperature of the combustion gas, Can be controlled within the allowable range.

In the above example, the control unit (not shown) basically controls the first and second valves 151 to 152 using the cooler 130 and the heat exchanger 120 as an example. However, depending on the types of the fuel cell 110 and the engine 140, the control unit (not shown) may be basically controlled such that at least a part of the anode off gas is directly transferred to the inflow path of the engine 140.

Although the control unit (not shown) controls at least one of the first and second valves 151 and 152 according to the temperature of the combustion gas, the control unit (not shown) The first valve 151 and the second valve 152 may be adjusted according to the temperature of at least one of the one exhaust gas from the heat exchanger 130, the temperature of the heat exchanged exhaust gas and the temperature of the combustion gas, to be. In this case, a plurality of temperature sensing units 170 may be provided.

At this time, if the temperature of the combustion gas exceeds the upper limit value of the allowable range, the controller (not shown) may increase the opening amount of the third valve 160 to quickly lower the temperature.

② Flow control when changing load condition

The control unit (not shown) senses the fluctuation condition of the load condition by the variation of the amount of fuel and the fuel utilization rate supplied to the fuel cell 110, and controls the first, second and third valves 151, 152, 160).

Here, the fuel cell-engine hybrid power generation system controls the amount of fuel supplied to the fuel cell 110 by controlling the fuel control valve (not shown) and the reformer supplied to the fuel cell 110, have. Therefore, the control unit (not shown) can know the supplied fuel amount, and the fuel utilization rate can be calculated from the output power of the fuel cell 110. At this time, since the reaction of the reformer is not predicted to be 100%, it is needless to say that the calculated fuel utilization rate may be different from the actual fuel utilization rate. For example, the fuel utilization rate can be calculated by the relationship of the output power of the fuel cell 110 with respect to the supplied fuel amount. To this end, the fuel cell-engine hybrid power generation system may further include a power meter (not shown).

Hereinafter, the control process of the first, second and third valves 151, 152 and 160 according to the relationship between the supplied fuel amount and the fuel utilization rate and the variation thereof will be described with reference to FIG.

In FIG. 3, the upper right end shows the case where the rated output is 100% (that is, the supplied fuel amount is the maximum), the fuel utilization rate is the maximum, and the lower left end is the case where the rated output (supplied fuel amount) and the fuel utilization rate are minimum. 3, the maximum value of the fuel utilization rate is 70%. However, theoretically, the maximum value of the fuel utilization rate may be 100% and the maximum value of the fuel utilization rate may be 70% to 90% depending on the efficiency of the power generation system. Therefore, the maximum value of the fuel utilization rate is not limited to FIG.

Since the fuel cell-engine hybrid power generation system is usually driven to produce a rated output, the load fluctuation situation is such that: a) both the supplied fuel amount and the fuel utilization rate decrease; And the like. Hereinafter, the control of the control unit (not shown) in each variation situation will be described.

If both the fuel supply and the fuel utilization are decreasing

(Right upper end → left lower end movement in FIG. 3)

When both the supplied fuel amount and the fuel use rate are reduced, the absolute amount of the anode off gas coming out of the fuel cell 110 is reduced, but the amount of the remaining fuel in the anode off gas is kept as the amount of the inert gas is reduced. Here, the inert gas may include moisture, CO2, Ar, N2, and the like.

In this case, the control unit (not shown) controls the first and second valves 151 and 152 so as to reduce the amount of water removed by the cooler 130 and maintain the amount of the inert gas at a similar level.

The control unit (not shown) controls the second valve 152 so that the anode off-gas transferred to the engine inlet path, that is, the first mixing pipe 181, is increased to increase the moisture content of the inert gas. For example, the control unit (not shown) may increase the amount of anode off-gas delivered to the first mixing pipe 181 in correspondence with the amount of reduction of the supplied fuel amount and the fuel utilization rate or the reduced water amount.

Further, when both the supplied fuel amount and the fuel use ratio are decreased, the amount of the inert gas is reduced while the fuel amount is kept close to each other, so that the concentration of the fuel gas in the combustion gas entering the engine 140 is increased, . Therefore, the composition ratio itself is good in reactivity, and if the temperature is lowered a little, ignition or combustion reaction may occur at a time similar to other cases. The controller (not shown) controls the first valve 151 so that the amount of one exhaust gas delivered to the bypass of the heat exchanger 120 is increased to lower the temperature of the anode offgas. At this time, the control unit (not shown) may control the first valve 151 according to the temperature of the combustion gas.

If the combustion gas needs to be further cooled, that is, if the temperature of the combustion gas is higher than the upper limit value, the controller (not shown) increases the opening amount of the third valve 160 to rapidly lower the temperature of the combustion gas .

In addition, when negative pressure is applied to the intake pipe of the engine 140, the control unit (not shown) increases the amount of opening of the third valve 160 so that the mixture gas The amount of air to be supplied from the air supply unit 20 is increased to prevent the negative pressure from being applied.

As described above, according to the present invention, when negative pressure is applied to the intake pipe of the engine 140 due to the decrease of the inert gas in the anode off-gas, the power generation of the engine 140 is interrupted or the engine 140 is damaged, It is possible to prevent an abnormal operation.

▶ If only the amount of fuel supplied decreases

(Right side → left side movement: right upper side → left upper side, right lower side → left lower side in FIG. 3)

When the fuel utilization rate does not change and the supplied fuel amount decreases, the ratio of the inert gas and the remaining fuel in the anode off-gas from the fuel cell 110 is similar but the absolute amount thereof decreases. In this case, the control unit (not shown) can perform the following two types of control.

In the first system, the air is throttled by the third valve 160 to mix the air with the combustion gas at the same rate as the rated operation of the fuel cell 110. At this time, the amount of the combustion gas flowing into the engine 140 is less than the total volume that can be input from the engine 140.

When performing the first mode, the controller (not shown) reduces the amount of air introduced by the third valve 160. However, when the amount of the combustion gas flowing into the engine 140 is extremely small, a negative pressure may be applied to the engine 140, so that the control unit (not shown) 151 and 152 to minimize the negative pressure applied to the engine 140 and to increase the temperature of the combustion gas as necessary.

In the second method, the third valve 160 is opened to the maximum, and the sum of the combustion gas and the introduced air amount is adjusted to the total volume that can be input from the engine 140.

When performing the second mode, the control unit (not shown) controls the temperature of the combustion gas by the first and second valves 151 and 152 after opening the third valve 160 as much as possible. In other words, when the third valve 160 is fully opened, the temperature of the combustion gas flowing into the engine 140 may be very low. Therefore, the control unit (not shown) controls the first and second valves 151 and 152 ) To increase the temperature of the combustion gas.

▶ When the fuel use rate decreases only

(Top-to-bottom movement in Fig. 3: right upper end? Right lower end, left upper end?

When the fuel utilization rate decreases, the amount of the anode off gas output from the fuel cell 110 is kept almost equal but slightly decreased, but the relative ratio of the remaining fuel is increased instead. In this case, in order to match the ignition timing and the combustion reaction to other cases, the control unit (not shown) controls the first and second valves 151 , 152 to control the temperature of the anode off gas to be decreased.

First, the control unit controls the second valve 152 so that the entire anode-off gas is delivered to the cooler 130 through the heat exchanger 120, and the entire exhaust gas from the cooler 130 Controls the first valve (151) to bypass the heat exchanger (120). The temperature of the combustion gas may be monitored to further control the first and second valves 151 and 152 as necessary. In addition, the control unit (not shown) may lower the temperature of the combustion gas flowing into the engine by controlling the amount of opening of the third valve 160 when the temperature of the combustion gas is not less than a predetermined upper limit value.

On the other hand, in the above-described example, there may occur a situation where the control according to the sensed temperature of the control unit (not shown) and the control process according to the load variation mutually conflict. In this case, the control unit (not shown) may perform the control according to the load variation first, and then perform the control according to the sensing temperature as necessary.

In the above-described example, the control unit (not shown) automatically controls the transfer ratio between the output paths of the first and second valves 151 and 152 and the opening amount of the third valve 160 by an electrical signal As an example. Alternatively, the control unit (not shown) may transmit an instruction to operate the first and second valves 151 and 152 or the third valve 160 through an output unit (not shown) such as a speaker or a display Output. Then, the user can confirm the output of the control unit (not shown) and manually operate the first and second valves 151 and 152 or the third valve 160. [

Further, in the fuel cell-engine hybrid power generation system according to the embodiment of the present invention, the temperature control of the combustion gas through the first and second valves 151 and 152 is no longer possible through an output unit (not shown) Or the adjustment of the temperature, the pressure or the composition ratio of the combustion gas through the third valve 160 is no longer possible, it can guide the user. Then, the user confirms whether there is a component that has failed in the fuel cell 110, the heat exchanger 120, the cooler 130, the first and second valves 151 and 152, the third valve 160, The failure of the component can be repaired.

As described above, in the embodiment of the present invention, the temperature of the anode-off gas is adjusted to a range that can increase the efficiency of the engine, thereby preventing engine failure, improving durability and causing stable combustion, .

In addition, the embodiment of the present invention can control the anode off-gas flowing into the engine even under a load fluctuation condition of the fuel cell to a temperature range and a composition range that can increase the efficiency of the engine and induce stable combustion.

Hereinafter, an anode off-gas adjusting method according to an embodiment of the present invention will be described with reference to FIG. 4 is a flowchart illustrating an anode off-gas adjusting method according to an embodiment of the present invention.

Referring to FIG. 4, the control unit (not shown) determines whether at least one of the supplied fuel amount and the fuel use rate is varied (S410).

When both the supplied fuel amount and the fuel use rate are decreased, the control unit (not shown) controls the first, second and third valves 151 (not shown) so that the temperature of the combustion gas is within the predetermined allowable range while raising the amount of the reduced inert gas , 152, and 160 (S420).

In detail, the control unit (not shown) controls the second valve 152 to selectively supply the anode off-gas to the first mixing pipe 181 corresponding to the amount of the inert gas reduced in accordance with the reduced supply amount of fuel and the fuel utilization rate. Increase the amount of gas. In addition, the control unit (not shown) controls the first valve 151 to increase the amount of the exhaust gas bypassing the heat exchanger 120 to regulate the temperature of the combustion gas. In addition, if additional cooling of the combustion gas is required, the controller (not shown) can increase the opening amount of the third valve 160 to rapidly lower the temperature of the combustion gas.

If the fuel usage rate does not change and only the supplied fuel amount decreases, the controller (not shown) controls the third valve 160 in one of the air throttling method and the maximum air amount supplying method (S430).

In the former mode, the control unit (not shown) throttles the amount of air by the third valve 160 corresponding to the reduced amount of the anode-off gas, and supplies the combustion gas to the combustion gas at the same rate as the rated operation of the fuel cell 110 Mix air. In this case, it goes without saying that the control unit (not shown) controls the temperature of the combustion gas by the first and second valves 151 and 152 in parallel.

In the latter mode, the control unit (not shown) regulates the temperature of the combustion gas to within a predetermined constant range by the first and second valves 151 and 152 after opening the third valve 160 as much as possible. In other words, when the third valve 160 is fully opened, the temperature of the combustion gas flowing into the engine 140 may be very low. Therefore, the control unit (not shown) controls the first and second valves 151 and 152 ) To increase the temperature of the combustion gas.

When the fuel utilization rate is decreased, the control unit (not shown) decreases the temperature of the anode offgas by the first and second valves 151 and 152 (S440). (Not shown) controls the second valve 152 so that the entire anode-off gas is delivered to the cooler 130 via the heat exchanger 120, And controls the first valve 151 so that the whole bypasses the heat exchanger 120. The temperature of the combustion gas may be monitored to further control the first and second valves 151 and 152 as necessary.

On the other hand, the control unit (not shown) controls the first and second valves 151 and 152 so that the temperature of the combustion gas is within the predetermined threshold range if there is no variation in the supplied fuel amount and the fuel utilization rate.

As described above, in the embodiment of the present invention, the temperature of the anode-off gas is adjusted to a range that can increase the efficiency of the engine, thereby preventing engine failure, improving durability and causing stable combustion, .

In addition, the embodiment of the present invention can control the anode off-gas to a temperature range and a composition range that can increase the efficiency of the engine and induce stable combustion even in a load fluctuation state of the fuel cell.

While the present invention has been described in detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to the above-described embodiments. Those skilled in the art will appreciate that various modifications, Of course, this is possible. Accordingly, the scope of protection of the present invention should not be limited to the above-described embodiments, but should be determined by the description of the following claims.

Claims (14)

A fuel cell for generating electricity by an electrochemical reaction of the input oxidizing agent and the fuel gas, and discharging an anode off gas;
A cooler for outputting a discharge gas as a result of performing at least one of cooling of the anode off-gas and removal of at least a part of moisture from the anode off-gas;
A heat exchanger having a first flow path through which the anode offgas flows and a second flow path through which the one exhaust gas flows, the heat exchanging the fluids in the first flow path and the second flow path;
A first valve for delivering a discharge gas from the cooler to at least one of a second flow path of the heat exchanger and a bypass of the heat exchanger;
A second valve for delivering the anode off-gas to at least one of a first flow path of the heat exchanger and an inflow path of the engine;
A third valve for supplying air to the open city; And
And a control unit for controlling at least one of the first, second, and third valves in accordance with at least one variation of a fuel supply rate supplied to the fuel cell and a fuel utilization rate by the fuel cell,
A combustion gas containing at least one of an exhaust gas passed through a second flow path of the heat exchanger and heat exchanged, a discharge gas delivered to a bypass of the heat exchanger, and an anode off gas transmitted through the second valve, A third valve for supplying the combustion gas to the engine for generating additional electricity by mixing with the air introduced from the third valve,
Wherein the control unit increases the amount of the anode off gas to be transferred to the inflow path of the engine under the control of the second valve when both the supplied fuel amount and the fuel use rate decrease, And the temperature of the combustion gas is controlled to be within a predetermined allowable range by regulating the first valve. 2. The fuel cell-engine hybrid power generation system according to claim 1, delete The apparatus of claim 1,
And calculates the fuel utilization rate from the output power of the fuel cell in relation to the supplied fuel amount. delete The apparatus of claim 1,
And the amount of opening of the third valve is increased corresponding to the temperature of the combustion gas when the temperature of the combustion gas is not less than the upper limit value of the allowable range. The apparatus of claim 1,
Wherein the fuel utilization rate is not changed and when the amount of supplied fuel is decreased, the amount of opening of the third valve is decreased to mix air with the combustion gas in a ratio corresponding to the rated output of the fuel cell. Engine Hybrid Generation System. The apparatus of claim 1,
And adjusting the temperature of the combustion gas to a predetermined allowable range by adjusting the first and second valves after opening the third valve to the maximum when the fuel usage rate is not changed and the supplied fuel amount is decreased Fuel cell - engine hybrid power generation system. The apparatus of claim 1,
The entire amount of the anode off-gas is transferred to the first flow path of the heat exchanger when the amount of the supplied fuel does not fluctuate and the fuel utilization rate decreases, and the entire of the one exhaust gas from the cooler is transferred to the bypass of the heat exchanger Wherein at least one of the first and second valves is regulated such that the temperature of the combustion gas is within a predetermined allowable range after controlling the first and second valves. A fuel cell for generating electricity by an electrochemical reaction of the input oxidizing agent and the fuel gas, a fuel cell for discharging an anode off gas, and an engine for generating additional electricity by burning the anode off gas, An anode off-gas regulator for regulating an anode off-gas of the anode off-
A cooler for outputting a discharge gas as a result of performing at least one of cooling of the anode off-gas and removal of at least a part of moisture from the anode off-gas;
A heat exchanger having a first flow path through which the anode offgas flows and a second flow path through which the one exhaust gas flows, the heat exchanging the fluids in the first flow path and the second flow path;
A first valve for delivering a discharge gas from the cooler to at least one of a second flow path of the heat exchanger and a bypass of the heat exchanger;
A second valve for delivering the anode off-gas to at least one of a first flow path of the heat exchanger and an inflow path of the engine;
A third valve for supplying air to the open city; And
And a control unit for controlling at least one of the first, second, and third valves in accordance with at least one variation of a fuel supply rate supplied to the fuel cell and a fuel utilization rate by the fuel cell,
Wherein the combustion gas, which is at least one of the one exhaust gas heat-exchanged through the second flow path of the heat exchanger, the one off gas delivered to the bypass of the heat exchanger, and the anode off gas delivered through the second valve, And is delivered to the engine,
Wherein the control unit increases the amount of the anode off gas to be transferred to the inflow path of the engine under the control of the second valve when both the supplied fuel amount and the fuel use rate decrease, The temperature of the combustion gas is controlled within a predetermined allowable range by controlling an amount of an inert gas to be supplied to the combustion chamber and regulating the first valve. delete delete 10. The apparatus according to claim 9,
Wherein the opening degree of the third valve is increased corresponding to the temperature of the combustion gas when the temperature of the combustion gas is not less than the upper limit value of the allowable range. 10. The apparatus according to claim 9,
When the fuel utilization rate does not fluctuate and the supplied fuel amount decreases, the amount of opening of the third valve is decreased to mix air with the combustion gas at a ratio corresponding to the rated output of the fuel cell, And adjusting the first and second valves to adjust the temperature of the combustion gas to a predetermined allowable range after opening the valve to the maximum. 10. The apparatus according to claim 9,
The entire amount of the anode off-gas is transferred to the first flow path of the heat exchanger when the fuel supply rate does not fluctuate and the fuel utilization rate decreases, and the whole of the one exhaust gas from the cooler is transferred to the bypass of the heat exchanger And controls at least one of the first and second valves so that the temperature of the combustion gas is within a predetermined allowable range after controlling the first and second valves.

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