WO2007143937A1

WO2007143937A1 - Hybrid power system for vehicle-use fuel cell, automobile including the system, the use of the system and the use of fuel cell stack

Info

Publication number: WO2007143937A1
Application number: PCT/CN2007/070012
Authority: WO
Inventors: Yun Tian
Original assignee: Yun Tian
Priority date: 2006-05-12
Filing date: 2007-05-14
Publication date: 2007-12-21
Also published as: CN101071864A

Abstract

A hybrid power system for vehicle-use fuel cell includes a fuel cell unit (1) and a gas turbine unit (2), wherein the fuel cell unit (1) comprises a fuel cell stack (11) and corresponding pipelines, the gas turbine unit (2) comprises a firebox (21), a compressor (22), a turbine (23), a generator (24) and corresponding pipelines. The present invention also discloses an automobile including the hybrid power system, the use of the hybrid power system and the use of fuel cell stack. The hybrid power system for vehicle-use fuel cell has high popularization value, can steadily run and can use other energy sources besides hydrogen gas.

Description

Vehicle fuel cell hybrid power unit, automobile including the same, use of the device, and use of fuel cell stack

Technical field

The present invention relates to a power unit, and in particular to a power unit of a vehicle. Background technique

At present, the research and development of existing fuel cell vehicles in the world are based on proton exchange membrane fuel cells.

(PEMFC), including direct methanol fuel cells (DMFC). However, electric vehicles or fuel cell hybrid vehicles based on proton exchange membrane fuel cells are difficult to commercialize in a short period of time for the following reasons:

(1) The cost is high. Proton exchange membrane fuel cells are expensive due to the use of precious metals (platinum) as catalysts;

(2) In the design of proton exchange membrane fuel cells, control is difficult because of the need to control the operating temperature and humidity within a narrow range, and the fuel cell itself generates water vapor and heat;

(3) The source of hydrogen. Hydrogen does not exist in nature and needs to be obtained by electrolyzing water or other fuel reforming. In the process, other high-quality energy (electricity) or fossil energy is inevitably consumed, thus reducing energy efficiency or pollution; DMFC uses methanol as fuel, Hydrogen is obtained by methanol reforming, and methanol is expensive and toxic; carbon monoxide produced by fossil energy reforming may also poison the catalyst or require the addition of a gas purification device;

(4) Hydrogen storage problem. The hydrogen liquefaction temperature is close to absolute zero and it is difficult to liquefy; Hydrogen absorption The development of the alloy has just begun, the price is high and the storage is small.

(5) Construction of gas stations. The construction cost of hydrogen refueling station is several times higher than that of ordinary gasoline refueling stations, which is difficult to popularize;

(6) The car starting process is very slow;

(7) Vehicle load adjustment is slow.

In summary, there is a lack of a fuel cell vehicle power plant with extended value, stability, and the ability to use energy other than hydrogen. Therefore, there is an urgent need in the art to develop such a device. Summary of the invention

It is an object of the present invention to obtain a fuel cell vehicle power plant that is of extended value, stable, and capable of using energy sources other than hydrogen. That provides a reduction in car pollution and reduced energy consumption. (Improve energy efficiency) and reduce solutions to excessive oil dependence.

Another object of the present invention is to provide a method of starting a rapid fuel cell hybrid vehicle for a vehicle.

Still another aspect of the present invention provides a load adjustment method for a rapid fuel cell hybrid vehicle for a vehicle.

Still another aspect of the present invention provides a vehicle including a power unit that reduces pollution.

Yet another aspect of the present invention provides a use of a fuel cell vehicle power unit.

Yet another aspect of the invention provides a use of a fuel cell stack. In a first aspect of the invention, a fuel cell hybrid power plant for a vehicle is provided, comprising: - a fuel cell unit comprising a fuel cell stack disposed on a main fuel pipe, the fuel cell stack being provided with an air supply Inflowing cathode inlet, anode inlet for fuel inflow, cathode outlet for air outflow, anode outlet for fuel outflow;

a gas turbine unit comprising a combustion chamber, a compressor, a turbine, a generator arranged in sequence, wherein a combustion chamber in the gas turbine unit communicates with an anode outlet in the fuel cell unit, and a compressor in the gas turbine unit communicates the fuel a cathode outlet in the battery unit;

And the fuel cell stack is a solid oxide fuel cell.

In a preferred embodiment of the invention, the solid oxide fuel cell stack is a solid oxide fuel cell stack comprising a start burner and a fuel reformer.

In a preferred embodiment, the power unit of the present invention is further provided with any one of the following devices or a combination thereof:

(i) a fuel bypass unit including a fuel bypass for fuel to flow into the combustion chamber;

(i i) an air bypass unit comprising an air bypass for the flow of air into the compressor;

(i i i) A steam generating unit comprising a steam generator, the steam generated by the steam generator being mixed with fuel and entering the anode inlet of the fuel cell.

In a preferred embodiment, the power unit of the present invention further includes a heat recovery unit, and the heat recovery unit includes:

An air regenerator and a fuel regenerator in communication with the turbine for recovering exhaust of the turbine such that the recovered exhaust heats air at the inlet end of the fuel cell stack and/or heats the fuel cell stack inlet End fuel The heat recovery unit communicates with the steam generating unit such that the recovered heat is used to generate steam. In a preferred embodiment, in the power unit of the present invention, the power ratio of the combustion battery unit and the gas turbine unit of the combustion battery unit is between 3:1 - 1 :1.

In a preferred embodiment, the power plant of the present invention employs a fuel that is a hydrocarbon fuel, including natural gas, methanol, and gas.

In a preferred embodiment of the invention, the fuel employed is natural gas.

In a preferred embodiment of the invention, the operating temperature of the combustion cell unit (1) is 700-100 CTC. In a preferred embodiment of the invention, the power device has an electrical efficiency of 55% to 65%.

In a preferred embodiment of the invention, the hydrogen utilization rate in the power unit is 80 ± 5%. Another aspect of the present invention provides a method for starting a fuel cell hybrid power plant for a vehicle. When starting, fuel enters a combustion chamber in a gas turbine unit through a main fuel pipe and a fuel bypass, respectively, and air passes through a fuel cell stack and an air bypass, respectively. Enter the compressor in the gas turbine unit and then enter the combustion chamber.

The fuel and compressed air are mixed and burned in the combustion chamber to drive the turbine to generate electricity, which causes the car to start. 5至两分钟。 In one embodiment of the present invention, the start time of the method is 0. 5 - 2 minutes. Still another aspect of the present invention provides a load adjusting method for a fuel cell hybrid vehicle for a vehicle, wherein an automobile load is adjusted by a flow rate of an air bypass and a gas bypass, and the time of the vehicle load adjustment process is 1 to 5 seconds. Still another aspect of the present invention provides an automobile including a power unit including a drive motor, a motor speed control device, a transmission device, a traveling device, a steering device, and a brake device. Yet another aspect of the present invention provides a use of a fuel cell vehicle power unit for a power source of an electric vehicle. Yet another aspect of the present invention provides a use of a fuel cell stack that is a solid oxide fuel cell, the fuel cell stack being used as a vehicle power source. BRIEF abstract

1 is a flow chart of power generation of a fuel cell hybrid power plant of the present invention;

Fig. 2 is a schematic view showing a specific embodiment of a vehicle equipped with the fuel cell hybrid power unit of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Through intensive and in-depth research, the inventors obtained the integrated characteristics of the power unit including the combustion battery unit and the gas turbine unit by improving the configuration and flow of the fuel cell vehicle power unit, and unexpectedly found that it is very suitable for application promotion, especially Natural gas can be used as a fuel, and it has high electrical efficiency, so it is particularly suitable as a power unit for electric vehicles. In addition, in a specific embodiment, a complete control scheme for starting and load adjustment is proposed for the vehicle operating characteristics, and a new high-efficiency power unit is obtained. The present invention has been completed on this basis. Fuel

The fuel of the present invention may employ a variety of hydrocarbon fuels including, but not limited to, gaseous fuels such as: biogas, liquefied petroleum gas, coal gas, natural gas, methanol. Natural gas is preferred.

The advantage of using natural gas as a fuel is that natural gas is readily available first. Natural gas can be obtained from nature, and hydrogen does not exist in nature. It needs to be recrystallized with electrolyzed water or other fossil fuels. In the process, other high-quality energy (electricity) or fossil energy is inevitably consumed, thus reducing energy efficiency. Or pollution is generated; secondly, the natural gas storage technology is mature, easy to store, and hydrogen is difficult to compress, and the liquefaction temperature is close to absolute zero, which is difficult to liquefy; the hydrogen absorption alloy is just beginning to be developed, the price is high and the storage capacity is small; The existing natural gas refueling station, and the construction cost of the hydrogen refueling station is several times higher than that of the ordinary gasoline refueling station, and it is difficult to popularize. Solid oxide fuel cell

The fuel cell used in the present invention is a solid oxide fuel cell (SOFC). The fuel cell is composed of a cathode, an anode, and an electrolyte sandwiched between the cathode and the anode. Preferably, the anode of the SOFC electrode material mainly includes yttria-stabilized zirconia (Yttrium (Y203) Stabi added with a conductive metal such as nickel Ni. Li zed Zirconia (Zr02), abbreviated as YSZ), the cathode mainly includes Antimony compounds (such as barium manganate, barium cobaltite and barium ferrite), the electrolyte mainly includes yttria-stabilized zirconia

(YSZ) or Scandium Doped Zirconia (SDZ). More preferably, the anode used in the battery of the present invention is nickel-doped yttria-stabilized zirconia (Ni-ZrO 2 ), cathode Lanthanum manganate (LaMn03) is used, and the electrolyte is yttria-stabilized zirconia (YSZ).

The solid oxide fuel cell (stack) typically includes a start burner and a fuel reformer.

Preferably, the solid oxide fuel cell of the present invention is an internally reformed solid oxide fuel cell. For example, preferably, the starter burner and the fuel reformer are integrated inside the fuel cell stack. In operation, gas and air enter the starter burner in the fuel cell stack through the anode inlet and the cathode inlet provided on the fuel cell stack, respectively, and are reformed by the fuel reformer before flowing through the anode and cathode of the fuel cell stack to generate electricity. The chemically reacted gas enters the combustion chamber and the compressor through the anode outlet and the cathode outlet provided on the stack, respectively. The starter burner is only used during cold start of the stack and is closed during normal operation and hot standby or hot start, when fuel and air bypass the start burner and enter the fuel reformer and fuel cell stack.

In one example of the reforming process, the fuel is natural gas and the main component is methane (CH ₄ ). In operation, natural gas reforming involves two equilibrium reactions:

Reforming reaction: CH ₄ + H ₂ 0 ^ CO + 3H ₂

Conversion reaction: CO + 3⁄40 ^ C0 ₂ + 3⁄4

The equilibrium constant of the internal reforming of the solid oxide fuel cell is determined by the temperature, and thus the amount of hydrogen produced is mainly determined by the temperature, that is, the amount of hydrogen generated and the reaction temperature have a great relationship. The molar ratio of water vapor to natural gas is between 2. 1 and 2. 5. In normal operation, the heat required for the reaction is provided by the heat released by the electrochemical reaction of the fuel cell stack, and no external heat source is required.

The operating temperature of the solid oxide fuel cell is preferably from 700 to 1000 °C.

The reformed fuel contains hydrogen, carbon monoxide, water vapor, carbon dioxide and residual natural gas. The oxide flowing through the cathode is oxygen, which can be pure oxygen or air, in this case air. When the air flows through the cathode, electrons are obtained from the cathode to form oxygen ions. The oxygen ions pass through the electrolyte to reach the anode, react with hydrogen and release electrons, and electrons flow to the cathode through the external circuit, thereby generating electric energy. The theory of power generation efficiency of the solid oxide fuel cell It can reach 70%-80%, and its power generation efficiency is actually 40%-50% in engineering applications.

The solid oxide fuel cell has a hydrogen utilization rate of preferably 80 ± 5%. The "fuel utilization rate" of the present invention means the ratio of the fuel participating in the chemical reaction to the total input fuel.

The solid oxide fuel cell of the present invention has lower manufacturing and maintenance costs than low temperature fuel cells such as protons Proton Exchange Membrane Fuel Cell (PEMFC), if used in the manufacture of automobiles, is much less expensive to manufacture than low-temperature fuel cell vehicles. Further, the solid oxide fuel cell of the present invention has a longer life than a low temperature fuel cell, is easy to manufacture, and has no problem of contamination of the battery.

In a preferred embodiment, an internal reforming solid oxide fuel cell is employed which can use the heat of the fuel cell to internally reform the natural gas to obtain the hydrogen required for the fuel cell, while for the PEMFC, if a fuel other than hydrogen is used, A separate external reformer and corresponding high temperature heat source are required.

In addition, since the solid oxide fuel cell used in the present invention is a high temperature fuel cell, preferably, the operating temperature can reach 700-1000 ° C, so that the heat of the fuel cell can be efficiently used to internally reform the natural gas to obtain a fuel cell. The hydrogen required. Gas turbine unit

The gas turbine unit of the present invention includes a combustion chamber, a compressor, a turbine, a generator, and a corresponding conduit thereof, the combustion chamber communicating with an anode outlet of a fuel cell stack in the fuel cell unit, the compressor being in communication with the fuel cell The cathode outlet of the fuel cell stack in the unit.

The combustor, compressor, turbine, generator and their respective conduits are arranged in accordance with structures well known to those skilled in the art. For example, in one embodiment, the compressor, the combustor, the turbine, and the generator are sequentially connected: after the air is pressurized in the compressor, it flows through the compressor outlet into the combustion chamber, and is mixed with the fuel in the combustion chamber. Combustion, the generated high-temperature gas enters the turbine, drives the turbine to rotate, and the turbine drives the generator connected to it to generate electricity.

The gas turbine unit of the present invention utilizes thermal energy generated in the fuel cell unit. The amount of power generated by the gas turbine unit and the amount of power generated by the fuel cell unit constitute the amount of power generated by the entire power unit.

Gas turbines can generate between 25% and 35% of the total power plant. The electrical efficiency of the entire power unit can reach 55-65% (based on the low fuel value LHV).

Heat recovery unit

The heat recovery unit of the present invention comprises: an air regenerator and a fuel regenerator in communication with the turbine for recovering exhaust of the turbine, such that the recovered exhaust gas heats the inlet end of the fuel cell stack And/or heating the fuel at the inlet end of the fuel cell stack. The heat recovery unit communicates with the steam generating unit such that the recovered heat is used to generate steam. When setting, first use the air regenerator to recover the heat of the turbine exhaust, and then use the fuel regenerator to recover. ^ Since the air flow is much larger than the fuel flow, depending on the configuration, it is about 18-25 times, so it must be Heat the air first to obtain a better fuel to air temperature difference.

In use, the heat in the turbine exhaust is first recovered by the air regenerator for heating the air, and the heated air enters the fuel cell stack; the heat in the turbine exhaust continues to be recovered by the fuel regenerator. In heating the fuel (such as natural gas), the heated fuel enters the fuel cell stack; finally, the residual heat in the turbine exhaust is used to heat the steam generator in the steam generating unit, causing the water therein to generate steam, the steam Enter the fuel cell stack as the steam required for internal reforming of the fuel.

In summary, the gas turbine of the present invention makes full use of the exhaust gas of the high-temperature fuel cell, so the comprehensive electric efficiency of the hybrid electric vehicle is higher than that of the low-temperature fuel cell electric vehicle, and is also much higher than that of the conventional internal combustion engine (diesel/gasoline engine), saving energy. . Moreover, since clean energy (natural gas) is used as fuel, it is clean emissions, so it is less polluting than conventional diesel engines and gasoline engine vehicles. Since clean energy (natural gas) is used and the energy conversion efficiency is 2-3 times that of the gasoline/diesel internal combustion engine, its emissions per kilometer are very low. Compared with ordinary internal combustion engine vehicles, the emission of carbon dioxide per kilometer is reduced by about 60%. (from 192 g/km to about 75 g/km); no volatile organic compound (V0C) emissions; no nitrogen oxides that destroy the ozone layer (should be discharged.

In the starting method of the present invention, according to the design of the fuel cell stack, a small amount of fuel and air enters the fuel cell stack starting burner through the main fuel pipe and the main air pipe, and the remaining fuel enters the combustion of the gas turbine unit through the fuel bypass. The remaining air enters the gas turbine compressor through the air bypass and then enters the combustion chamber. The fuel and compressed air are mixed and burned in the combustion chamber to generate high temperature and high pressure gas, which drives the turbine to generate electricity, and drives the motor to start the vehicle. The main fuel pipe here refers to: a pipe through which a fuel passes through a fuel cell unit (anode) to a combustion chamber.

The main air duct here refers to: the duct through which the air passes through the fuel cell unit (cathode), to the compressor, and then to the combustion chamber.

Since the above method is used for starting, the starting time of the car is determined by the starting time of the gas turbine. 5至两分钟。 The time of the starting time of the present invention is 0. 5-2 minutes. 5至一个分钟。 Preferably, 0. 5 - 1 minute. The "starting time" referred to in the present invention means: the time from the initial start to the time when the gas turbine load is stable (maximum load condition). Among them, the amount of fuel entering the main fuel pipe and the fuel bypass at the initial stage of starting is determined according to the design of the power system, for example, according to the gas turbine/fuel cell power ratio characteristic. The ratio of the total fuel bypass to the main fuel pipe is 0-40%. In addition, the flow in the fuel bypass can range from 100% at the beginning of the start-up to 0% at the steady load (optimal operating conditions) (complete bypass of the fuel bypass).

The amount of air entering the main air duct and air bypass at the beginning of the start-up is based on the design temperature of the fuel cell stack and the gas turbine/fuel cell power ratio. The ratio of the general air bypass to the main air duct is 70% 255%.

The ratio of air flow to gas flow at the initial stage of startup is 40-50 times, preferably 45 times. While gradually heating the fuel cell stack to the operating temperature and increasing the fuel cell power to the design value, the ratio of air flow to gas flow is gradually reduced to 18-30 times. Adjusting the ratio of fuel to air varies according to fuel characteristics, startup process and The difference in operating process, as well as the power ratio of the gas turbine/fuel cell stack, varies from the respective operating temperature settings of the gas turbine and fuel cell stack.

Due to the unique control method, the automobile of the present invention can be provided with a quick start capability, which solves the problem that the fuel cell electric vehicle usually starts slowly. In particular, the output power of the fuel cell stack and the micro gas turbine can be individually controlled, thereby ensuring that the vehicle can quickly meet the adjustment requirements while keeping the entire system in an efficiency-optimized state. Load adjustment method

In the load adjustment method of the present invention, the vehicle load is adjusted by adjusting the air bypass air and the corresponding gas bypass fuel flow rate, and the load adjustment time is between 15 seconds.

The "load adjustment time" described in the present invention refers to the time from the initial stage of input of the vehicle load change command to the time of reaching a new stable load.

When the load is adjusted, the additional power of the gas turbine can be obtained by providing additional fuel through the fuel bypass unit, thereby reducing the time for load adjustment. At the same time, the corresponding operation of the air bypass unit allows the gas turbine unit to maintain the designed combustion temperature and efficiency without affecting the operating temperature of the fuel cell stack.

The power of a gas turbine varies between 50% and 100% to meet changes in vehicle load.

The magnitude of this load regulation capability is determined by the rated load of the fuel cell stack and the set gas turbine/fuel cell power ratio. Generally, if the set gas turbine/fuel cell power ratio is larger, the load regulation capability is stronger, but the overall energy conversion efficiency of the system during steady state operation is reduced, so it needs to be negative. Balanced load regulation and overall conversion efficiency of the hybrid system. The main need to consider this balance is the use of the car (bus/car, road conditions, etc.) and customer needs.

Typically, the ratio of fuel to main fuel piping that enters the fuel bypass at the beginning is adjusted from 0% to 40%. At the beginning of the start-up, the amount of air entering the air bypass and the main air duct is 70% - 255%.

The ratio of air flow to gas flow at the initial stage of startup is 40-50 times, preferably 46 times. At normal load, the ratio of air flow to gas flow is reduced by 18-30 times. In a typical system configuration, when the gas turbine/fuel cell stack power ratio is 33%, the total air flow during normal load operation is fuel. About 19 times. However, when the system design is performed, if the set gas turbine/fuel cell stack power ratio is increased (greater than 33%), the ratio of total air flow to fuel flow will increase during normal load operation. Big. car

The vehicular fuel cell hybrid device of the present invention is used in automobiles, particularly electric buses and cars. The vehicular fuel cell hybrid device of the present invention can also be applied to a mobile originating station, a military mobile power generating system, a drone, a submarine power system, etc. The present invention will be further clarified in conjunction with specific embodiments. It is to be understood that the examples are not intended to limit the scope of the invention. The experimental methods in which the specific conditions are not specified in the following examples are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturer. The ratio and percentage are based on the molar amount (mol) unless otherwise stated. Embodiment 1 : Vehicle natural gas fuel cell hybrid device and its automobile

Vehicle natural gas fuel cell hybrid power unit

Referring to the configuration and flow chart of the power unit of FIG. 1 , the vehicle natural gas fuel cell hybrid power unit comprises a fuel cell unit 1, a gas turbine unit 2, a fuel bypass unit 3, an air bypass unit 4, a steam generating unit 5, and a heat recovery unit. 6 composition. Others include an auxiliary pump such as a transfer pump A, a transfer pump B, and the like. The fuel cell unit 1 includes a fuel cell stack 11 (including a built-in starter burner and a fuel reformer, not shown) disposed on the main fuel pipe 12. The fuel cell stack 11 is provided with a cathode inlet 11a through which air flows, an anode inlet 11A through which fuel flows, a cathode outlet 11b through which air flows, and an anode outlet 11B through which fuel flows. The gas turbine unit 2 includes a combustion chamber 21, a compressor 22, a turbine 23, and a generator 24, which are sequentially disposed, wherein the combustion chamber 21 in the gas turbine unit 2 communicates with the anode outlet 11B in the fuel cell unit 1, the gas turbine unit 2 The compressor 22 in communication communicates with the cathode outlet 1 lb in the fuel cell unit 1.

The fuel bypass unit 3 includes a fuel bypass 31 for supplying fuel into the combustion chamber 21.

The air bypass unit 4 includes an air bypass 41 for supplying air into the compressor 22.

The steam generating unit 5 includes a steam generator 51, and the steam generated by the steam generator 51 is mixed with fuel to enter the anode inlet 11A of the fuel cell. The water from steam generator 51 comes from a vapor condenser 52 that is in communication therewith.

The heat recovery unit 6 includes an air regenerator 61 and a fuel regenerator 62 that are in communication with the turbine 23 and are used to recover the exhaust of the turbine 23 such that the recovered exhaust heats the fuel cell stack inlet end 1 1a of air and / or fuel 1 1A of fuel at the inlet end of the fuel cell stack. The heat recovery unit 6 is connected to the steam generating unit 5 such that the recovered heat is used to generate steam.

Figure 1 is a flow chart of the powertrain, showing detailed fuel, air, water, and water vapor connections in the system and how the system utilizes the fuel cell stack and the thermal energy of the microturbine. In this system, the fuel cell stack 1 1 is in the upper part of the cycle, while the micro gas turbine 2 is in the lower part of the cycle.

As is apparent from Fig. 1, the power source of the power unit of the present invention includes a fuel cell 1 (SOFC) and a micro gas turbine 2. The fuel of the system is preferably natural gas. Since the high temperature fuel cell 1 has an electrical conversion efficiency of up to 50% (theoretically 70% to 80%), and the micro gas turbine 2 utilizes the waste heat of the fuel cell 1 and the remaining fuel, it is not required in normal operation conditions. Additional fuel (at specific gas turbine/fuel cell stack power ratios and rated conditions; in other cases, if a larger power ratio is set or under non-rated conditions, fuel bypass may need to be turned on Supplying additional fuel), so the overall system electrical efficiency reaches 55%~65%. This efficiency is much higher than other types of vehicles, such as internal combustion engines, hybrid vehicles (internal combustion engines + batteries), and proton exchange membrane fuel cells (PEMFC).

The power generation unit is a hybrid power generation system composed of a fuel cell 1 and a gas turbine 2, which is a complex and efficient power generation system with preheating, regenerative and natural gas reforming. The operating temperature of the fuel cell 1 is between 700 ° C and 1000 ° C, and the operating temperature of the micro gas turbine combustor 21 is around 1 100 ° C. Depending on the requirements of different fuel cells and gas turbines, the inlet pressure of fuel and air may vary slightly, typically around 1 bar.

The fuel (i.e., natural gas) enters the anode 1 1A of the fuel cell stack and the combustion chamber 21 of the gas turbine in two ways. The fuel entering the combustion chamber 21 of the gas turbine is used for load adjustment and control. Rated load In this case, the fuel is heated from normal temperature to about 500 ° C before entering the fuel cell stack anode 11A. The fuel undergoes internal reforming to produce hydrogen. The chemical reaction equilibrium constant for internal reforming is determined by the operating temperature of the stack (the reaction equilibrium constant can be described as a function of temperature), and thus the amount of hydrogen produced is also determined primarily by temperature. An electrochemical reaction occurs in a fuel cell, which combines with oxygen ions passing through the electrolyte to form water and generate electricity and heat. By adjusting the amount of air entering the fuel cell stack, the fuel cell stack operating temperature can be maintained at 700-1000 °C. The hydrogen utilization rate of the fuel cell stack is maintained at around 80%. The molar flow ratio of air (cathode) to natural gas (anode) at the fuel cell inlet is approximately 12:1, which allows the fuel cell to maintain the desired reaction temperature and reaction concentration. The exhaust gas 11B of the fuel cell anode is mostly generated. The water vapor (molar concentration: about 70%) contains unreacted methane, carbon monoxide and hydrogen, each of which is about 10%, and is introduced into the micro gas turbine combustion chamber, and is mixed with compressed air to drive the turbine 23 to generate electric power.

The exhaust of the micro gas turbine is discharged from the turbine and has a very high temperature (~600°0, which is used to heat the inlet air and fuel. After the air is heated by the heat recovery unit, it flows through the start burner and the fuel cell stack 11 , in the starter burner is further heated to a set temperature (such as about 800 ° C, determined by the stack performance design), and heats the fuel cell stack 11. When the fuel cell stack 11 temperature reaches the internal reforming required for a few chemical reactions At the temperature (~700 ° C), the start burner is turned off, the fuel will flow directly to the internal reformer and the fuel cell stack anode 11A, generating hydrogen, carbon monoxide and carbon dioxide under the internal catalytic reforming reaction. Hydrogen and oxygen in the fuel cell After the stack 11 reaction, the temperature of the fuel cell stack 11 continues to rise until the operating temperature (700 ° C - 1000 ° C). The startup process of the solid oxide fuel cell stack 11 is based on the fuel cell type (plate / tube) and material thermal load Features, currently within 10 to 30 minutes.

When the system is in normal operation, the fuel bypass 31 can be in the closed state to obtain the best efficiency, and part of the fuel can be directly used in the micro gas turbine 2 according to the system design requirements, so that the load proportion of the micro gas turbine 2 can be increased. Increase start and load adjustment capabilities. However, in normal operation (design conditions), if the flow rate of the fuel bypass 31 is too high, the efficiency of the entire system may be degraded. According to the gas turbine/fuel cell stack load ratio, it can be zero flow, and the system has the highest efficiency; under other load ratio design, it is also possible to achieve 30% or more of the total fuel consumption, but, as mentioned above When the fuel bypass flow is greater than zero, the load regulation capability of the system is enhanced, but the overall electrical efficiency of the system is reduced. Therefore, a preferred ratio of the flow rate of the fuel bypass 31 to the flow rate of the main fuel conduit 12 is between 0% and 40%. For automotive applications, it is preferably between 10% and 30%, and optimally between 15% and 25%. For stationary power station applications, the best is 0%. To accommodate the adjustment of the fuel bypass, the air bypass 41 also automatically adjusts the amount of air entering the microturbine based on a predetermined optimized value to maintain the designed combustion temperature and efficiency of the microturbine 2. Because this portion of the air does not pass through the fuel cell stack, it does not affect the operating temperature and chemical reaction of the fuel cell stack. The operating temperature of the fuel cell stack 11 will be adjusted by the flow of air through the cathode stack 11a of the fuel cell stack.

By separately controlling the fuel bypass 31 and the air bypass 41, the operating temperature, reaction concentration and output power of the fuel cell stack and the micro gas turbine can be individually controlled so that both operate at higher efficiency, and the output power of the entire system is also satisfied. Load requirements.

After the fuel cell stack 1 1 is in normal operation, the fuel cell stack 1 1 will be kept at the rated load as much as possible, and the micro gas turbine 2 will adjust the load accordingly to meet the overall load requirements. Car start control method

At startup, gas (i.e., natural gas) enters the fuel cell stack through the main fuel conduit 12, respectively. 1 Starts the combustor and fuel bypass 31 conduits into the microturbine combustor 21, and the air passes through the fuel cell stack 1 1 and the air bypass 41, respectively. After entering the micro gas turbine compressor 22, the fuel and the compressed air are mixed and burned, and the turbine 23 is driven to generate electricity, and the vehicle is started immediately. In this case, the starting time of the car will be determined by the start-up time of the micro gas turbine, and the starting time is about 0.5-2 minutes. Load control in vehicle operation

At the same time, in order to solve the problem of rapid adjustment of load during vehicle operation, the following schemes are proposed:

When the car is in normal operating conditions, the fuel bypass 31 is off or only a small portion of the flow. However, the vehicle needs to be accelerated or climbed more than normal operating power, at which point additional fuel can be supplied to the micro gas turbine 2 through the fuel bypass unit 3 (and the air bypass flow is increased accordingly to meet the gas turbine's control of the combustion temperature). Thus additional power can be obtained immediately, which avoids the long time required to adjust the fuel cell stack 11. At the same time, the fuel cell stack will also gradually adjust its power so that the overall system efficiency reaches an optimum value at this power.

At the same time, the air enters the cathode 1 1a of the fuel cell stack and the compressor 22 of the micro gas turbine in two ways. The air entering the compressor 22 of the micro gas turbine is used to regulate the combustion temperature and perform load control. Before entering the fuel cell stack cathode 1 1a, the air is heated from normal temperature to about 650 ° C, and enters the combustion. The air of the cathode 11a of the battery stack generates oxygen ions under the electrochemical reaction, and the oxygen ions pass through the electrolyte and combine with the hydrogen gas, and the released electrons reach the cathode through the external circuit, thereby generating electric power. The air of the cathode outlet 11a of the fuel cell stack enters the micro gas turbine. Before the compressor 22, the temperature after mixing with the bypass air is about 400-500 °C. After the air is compressed, it is further heated to about 1100 ° C in the combustion chamber 21 to drive the turbine 23 to generate electric power.

The exhaust gas temperature of the micro gas turbine 2 is about 600 ° C. The exhaust gas respectively heats the air and fuel at the inlet end l la, 11A of the fuel cell stack, the temperature is lowered to about 400 ° C, and then the water is generated by the steam generator 51. Water vapor, water vapor is introduced into the fuel cell internal reformer and reformed with fuel to produce the hydrogen required for the electrochemical reaction. The exhaust gas contains water generated by an electrochemical reaction, is recovered in the condenser 52, and is recycled.

The total power generation of the entire system is the sum of the power generation of the fuel cell and the gas turbine. Since the micro gas turbine fully utilizes the exhaust heat of the high temperature fuel cell stack and generates additional power, the electrical efficiency of the entire system can reach 55%-65%.

The power of this hybrid system can be arbitrarily adjusted according to actual needs. It can be used for stationary power stations (hundreds of kW to several liters) or for automotive powertrains. Depending on the design power of the existing main components, the power of the entire automotive system is usually above 20 kW. For electric vehicles, the power demand is generally 60kW-150kW (sedans) or 150kW-250kW (buses, buses).

For a given power, the power of the fuel cell and the gas turbine can also be adjusted according to the operating requirements of the system. The main fuel flow, the bypass fuel flow, the main air flow, the bypass air flow, and the heat exchanger heat exchange amount will all occur accordingly. The change, but the pressure and operating temperature of each subsystem is basically fixed, maintaining the design value, such as the fuel cell stack at 700-1000 ° C, the micro gas turbine combustor temperature is around 1100 ° C.

For example, for an ordinary family car, if the electric power required for the entire car is 80 kW, the main parameters of the system under standard design conditions are as follows: Fuel cell stack fuel cell stack fuel cell stack micro gas turbine micro gas micro gas Wheel stack power stack air flow stack fuel consumption machine power turbine bypass machine bypass air

(kW) (kg/h) Quantity (kg/h) (kW) Fuel consumption Consumption (kg/h) (kg/h)

60 111. 5 10. 0 20 0 78. 5 In the system simulation test, the design efficiency of the hybrid system reached 60% (based on the low heat value LHV).

In start-up and regulated operation, as described above, the system has adopted a flexible load distribution and control method; however, in the initial design of the system, for example, the power ratio of the fuel cell to the gas turbine can also be flexibly changed. For example, for the above 80kW car power system, the following design can also be used.

Compared with the previous solution, this solution improves the starting and load regulation performance of the gas turbine/fuel cell stack. However, since the micro gas turbine itself consumes part of the fuel, the overall efficiency under design conditions. Only 83% of the previous solution. In the actual situation, it is necessary to specifically consider the vehicle use and customer demand, and achieve a balance between quick start and rapid load adjustment and system efficiency. Under this balance, the car starter is satisfied. The minimum power required, in turn, minimizes the ratio of fuel bypass to main fuel bypass flow under steady load to achieve higher system efficiency unless designed for a stable load with fuel bypass and main fuel depending on vehicle use and customer requirements The bypass flow ratio is 0, otherwise the bypass process is not closed, only the process of regulating the bypass flow. For other power output requirements, the above design parameters can be changed accordingly. Natural gas vehicle fuel cell hybrid vehicle

Referring to Figure 2, the main components of the fuel cell hybrid electric vehicle for natural gas driven vehicles are shown. The utility model comprises a fuel cell unit 1, a gas turbine unit 2, a steam generating unit 5, a heat recovery unit 6, and an electric motor 7, an automobile control system 8, and a natural gas storage tank 9. Other devices not shown in the drawings include motor speed control devices, transmission devices, traveling devices, steering devices, braking devices, and the like. The installation of all devices can also be adapted in accordance with well-known techniques of the prior art.

The natural gas storage tank 9 and the automotive electronic control system 8 are located at the rear of the vehicle, the fuel cell unit 1 and the gas turbine unit 2, the heat recovery unit 6 (including the regenerator 61/62, not shown), steam generation The unit 5 includes a steam generator 51 (or atomizer), and the condenser 52 is located at the front of the vehicle.

The system of the present invention is the first to propose the use of high temperature fuel cell SOFC for automotive applications. In automobiles, the fuel system also includes a high-pressure natural gas storage tank 9, a natural gas distribution control system (not shown), and a gas filling device (not shown).

The drive motor uses a DC series motor or a DC brushless motor (DCBM).

The motor speed control device adopts thyristor chopper speed regulation.

Due to the start-up and speed-shifting of the motor, the clutch, transmission, reverse gear and differential of the conventional internal combustion engine can be omitted.

The control system 8 controls the input amount (main/auxiliary fuel supply and main/auxiliary air supply) according to the control strategy described herein according to external load requirements and different operating conditions of the system (starting, stable operation and load regulation). And accept feedback from parameters such as operating temperature, pressure, flow, power, gas concentration, external load magnitude, etc. of each component, and further adjust each input amount separately by methods well known to those skilled in the art.

All documents mentioned in the present application are hereby incorporated by reference in their entirety in their entireties in the the the the the the the the the In addition, it should be understood that various modifications and changes may be made by those skilled in the art in the form of the present invention.

Claims

Rights request

A vehicle fuel cell hybrid power unit characterized in that it comprises:

a fuel cell unit (1) comprising a fuel cell stack (11) provided on a main fuel pipe (12), said fuel cell stack (11) being provided with a cathode inlet (11a) for inflow of air for fuel inflow An anode inlet (11A), a cathode outlet (l ib) for supplying air, and an anode outlet (11B) for supplying fuel;

- a gas turbine unit (2) comprising a combustion chamber (21), a compressor (22), a turbine (23), a generator (24),

Wherein the combustion chamber (21) in the gas turbine unit (2) communicates with the anode outlet (11B) in the fuel cell unit (1), and the compressor (22) in the gas turbine unit (2) communicates with the fuel cell unit (1) Cathode outlet (l ib) in ;

And the fuel cell stack (11) is a solid oxide fuel cell.

2. The power unit according to claim 1, wherein the power unit is further provided with any one of the following: or a combination thereof:

(i) a fuel bypass unit (3) including a fuel bypass (31) for supplying fuel into the combustion chamber (21); (ϋ) an air bypass unit (4) including air for the compressor to flow into the compressor ( 22) an air bypass (41); (iii) a steam generating unit (5) including a steam generator (51), the steam generated by the steam generator (51) being mixed with fuel and entering the anode inlet of the fuel cell ( 11A).

3. The power unit according to claim 1 or 2, further comprising a heat recovery unit (6), the heat recovery unit (6) comprising:

An air regenerator (61) and a fuel regenerator (62) communicating with the turbine (23) for recovering the exhaust of the turbine (23), such that the recovered exhaust gas heats the fuel cell The air at the inlet end (11a) of the stack and/or the fuel at the inlet end (11A) of the fuel cell stack;

The heat recovery unit (6) is connected to the steam generating unit (5) such that the recovered heat is used to generate steam.

The power unit according to claim 1 or 2, characterized in that the power ratio of the combustion battery unit (1) and the gas turbine unit (2) of the combustion battery unit is between 3:1 - 1 :1.

The power unit according to claim 1 or 2, wherein the fuel used is a hydrocarbon fuel, including natural gas, methanol, and gas.

6. A method of starting a fuel cell hybrid power plant for a vehicle, characterized in that, at startup, fuel enters the gas turbine unit (2) through a main fuel pipe (12) and a fuel bypass (31), respectively. Combustion chamber (21),

The air enters the compressor (22) in the gas turbine unit (2) through the fuel cell stack (11) and the air bypass (41), and then enters the combustion chamber (21).

The fuel and compressed air are mixed and burned in the combustion chamber (21) to drive the turbine (23) to generate electricity, causing the vehicle to start.

A load adjusting method for a fuel cell hybrid vehicle for a vehicle, characterized in that the vehicle load is adjusted by a flow rate of an air bypass (41) and a gas bypass (31), wherein the time of the vehicle load adjustment process is 1 A 5 second.

8. A vehicle comprising the power unit of claim 1 comprising a drive motor (7), a motor speed control device, a transmission, a travel device, a steering device and a brake device.

9. Use of a fuel cell vehicle power unit according to claim 1 in a power source for an electric vehicle.

10. Use of a fuel cell stack, the fuel cell stack being a solid oxide fuel cell, characterized in that the fuel cell stack is used as a vehicle power source.