CN1305161C - Hybrid power system for vehicle-use fuel cell gas curbine - Google Patents

Abstract

The vehicle-used fuel cell gas turbine hybrid power system belongs to the technical field of impeller mechanical design of fuel cell systems. It is characterized in that it is connected to an air bypass pipe through a flow distribution valve on the air intake pipe of the vehicle fuel cell stack, the outlet end of the pipe is connected to a combustion chamber, and the other air inlet of the combustion chamber is connected to the vehicle. The hydrogen output pipeline of the fuel cell stack, hydrogen and excess air are burned in the combustion chamber, and the gas is passed to the turbine. While providing power for the air compressor, the excess energy can also be converted into electrical energy output through the generator. The invention adopts the hybrid power generation method of the fuel cell and the gas turbine, which can improve the efficiency and reliability of the power system.

Description

Vehicle Fuel Cell Gas Turbine Hybrid Power System

Technical field:

The invention belongs to the technical field of fuel cells, in particular to the technical field of fuel cell power systems for vehicles.

Background technique:

Under the dual pressure of energy crisis and environmental protection, major international automobile companies are committed to developing new energy and pollution-free fuel cell vehicles. One of the key technologies in

Most of the existing fuel cell systems for vehicles are direct fuel cell systems, which are different from reforming fuel cell systems, and directly use the hydrogen source on the vehicle to work. According to the boost pressure of the fuel cell air system, the vehicle fuel cell system is divided into a pressurized fuel cell system and a low pressure fuel cell system. The pressurized fuel cell system uses an air compressor as the flow power of the air system, and the boost pressure ratio is 1.6 to 2.5; the low-pressure fuel cell system uses a blower as the flow power of the air system, and its boost pressure ratio is below 1.5. Higher boost pressure can increase the density of air flowing into the fuel cell and increase the power density of the fuel cell system, so pressurized fuel cell systems are more widely used.

Existing pressurized fuel cell systems for vehicles suffer from three drawbacks:

(1) The air compressor is prone to surge and blockage: the working condition of the vehicle fuel cell system changes frequently, and the air flow rate changes accordingly. Taking a 60kW fuel cell engine as an example, its flow range is about 0.01-0.1kg/s. In the case of low flow, the air compressor is prone to surge; in the case of high flow, the air compressor is prone to clogging, which will seriously deteriorate the performance of the vehicle fuel cell system.

(2) Low efficiency: The air compressor consumes a lot of power, resulting in a lower system net efficiency than the low-voltage fuel cell system. In order to improve this defect, a turbo expander is used for energy recovery, but the exhaust energy of the fuel cell system is small, and the power obtained by the turbo expander is not enough to independently drive the air compressor. Countries usually use two-stage supercharger solutions to solve this problem: one-stage It is the turbocharger, and the other stage is the motor-driven compressor booster. The advent of electrically assisted turbochargers now enables one-stage boosting.

(3) The hydrogen utilization rate is low or the power consumption of the hydrogen pipeline is large. The flow power of hydrogen can be generated by two methods: one is to use the purge method (intermittent exhaust method) to put part of the air into the atmosphere, which results in a low utilization rate of hydrogen; the other is to use a hydrogen circulation pump to circulate the hydrogen , which will consume additional system power.

Invention content:

Aiming at the defects existing in the existing vehicle fuel cell system, the present invention proposes a vehicle fuel cell gas turbine hybrid power system, which overcomes the above-mentioned defects of the existing vehicle fuel cell system, in order to ensure that the air compressor works in a relatively For stable working conditions, the flow rate is stable, and a combustion chamber and a bypass pipe are added to the system. The excess air not needed by the fuel cell stack flows into the combustion chamber from the bypass pipe, thereby stabilizing the flow rate of the air compressor. The gas burned in the combustion chamber flows into the turbine to provide energy for the air compressor, and the excess energy is output by the generator. This ensures that the air compressor has been working in a stable working condition, and at the same time improves the efficiency of the system.

The present invention contains a hydrogen source (1), a fuel cell stack (4), an air compressor (7), a turbine (11), an integrated motor/generator (12), and is characterized in that it also contains a flow distribution valve ( 8) A section of air bypass line (9) connected to the air intake line of the vehicle fuel cell stack (4), the air inlet of the flow distribution valve (8) is connected to the output port of the air compressor (7) , one of its air outlets is connected to the air inlet of the vehicle fuel cell stack (4), and the other air outlet is connected to the air inlet of the air bypass pipeline (9), and the air bypass pipeline The air outlet of (9) connects the air exhaust pipeline of described vehicle fuel cell stack; Also contains a combustion chamber (10), and an air inlet of described combustion chamber (10) connects described vehicle fuel cell stack (4) the hydrogen output pipeline (17), the air in the air bypass pipeline (9) and the air exhaust pipeline of the vehicle fuel cell stack (4) flows into the combustion chamber (10) together ), the gas outlet of the combustion chamber (10) is connected to the turbine (11) of the vehicle fuel cell system.

Another solution of the present invention contains a hydrogen source (1), a fuel cell stack (4), an air compressor (7), a turbine (11), and an integrated motor/generator (12). A flow distribution valve (8) is connected to a section of air bypass pipeline (9) on the air intake pipeline of the vehicle fuel cell stack (4), and the air inlet of the flow distribution valve (8) is connected to the air compressor (7 ) output port, one of its air outlets is connected to the air inlet of the vehicle fuel cell stack (4), and its other air outlet is connected to the air inlet of the air bypass pipeline (9); it also contains a A combustion chamber (10), one inlet of the combustion chamber (10) is connected to the hydrogen output pipeline (17) of the vehicle fuel cell stack (4), and the other inlet is connected to the air bypass The outlet of the pipeline (9) is connected to the air exhaust pipeline of the vehicle fuel cell stack (4), and the air exhaust pipeline is connected to the turbine (11) of the vehicle fuel cell system.

The experiment proves that the present invention adopts the hybrid power generation method of the fuel cell and the gas turbine, can improve the efficiency and reliability of the power system, and achieves the expected purpose.

Description of drawings:

Fig. 1 is embodiment one of the present invention;

Fig. 2 is the second embodiment of the present invention.

Detailed ways:

The specific embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in Figure 1, the present invention is aimed at the vehicle fuel cell system, (1) is the vehicle hydrogen source, usually a high-pressure hydrogen cylinder filled with high-pressure gaseous hydrogen. Hydrogen flows from the hydrogen source (1) into the high-pressure hydrogen pipeline (2), passes through the pressure reducing valve (3) to reach the hydrogen flow and pressure required by the stack, flows into the low-pressure hydrogen pipeline (16), and enters the fuel cell stack (4). In order to ensure that the fuel cell stack can have sufficient reaction gas, the excess coefficient of hydrogen entering the stack is greater than 1, that is, about excess hydrogen flows out of the stack (4) and enters the combustion chamber (10) through the hydrogen tailpipe (17). Hydrogen combustion avoids the loss of hydrogen by venting it into the air.

As shown in Figure 1, the air compressor (7) sucks in air from the atmosphere (5) through the intake pipe (6), and the air compressor should work at the rated working condition due to the structure of the air system, and should not follow the fuel cell stack ( 4) The working conditions vary. However, since the air flow required by the fuel cell stack changes, the flow of the air compressor also changes, which affects its working conditions. A solution that can stabilize the flow must be used to solve this problem. The present invention adopts the mode of adding an air bypass pipeline and a combustion chamber in the system, as shown in FIG. 1 . The air compressor exhaust is divided into two paths through the flow distribution valve (8), one path enters the fuel cell stack (4) through the fuel cell air intake line (15), and the flow rate of this path is controlled by the flow distribution valve (8). Stack (4) operating conditions vary, and its excess air coefficient is greater than 1. The other way is excess air, which is mixed with the air flowing out of the electric stack at the pipeline (14) and enters the combustion chamber (10) through the air bypass pipeline (9).

In the combustor (10), hydrogen is combusted to generate high-temperature and high-pressure gas, the temperature of which can reach 900K, and enters the turbine (11) through the pipeline (18). The required energy is transmitted to the air compressor (7) through the common shaft (19), and another part of the mechanical work is generated and output by the coaxial integrated motor/generator (12) as part of the power output of the fuel cell system. The exhaust air after passing the turbine is discharged into the atmosphere (13).

The motor/generator (12) is an integrated design, the motor is used when the air compressor (7) is started, and the generator is used to convert the mechanical work output by the turbine (11) into electrical work output.

The invention ensures that the compressor always works near the rated working condition, and avoids surge and blockage. The hydrogen is burned in the pressurized air to generate high-temperature and high-pressure gas to drive the turbine to do work, which improves the energy utilization rate.

The invention can realize an independent fuel cell cycle when the combustion chamber is not working, and the power of the air compressor is provided by a motor, and can also realize an independent gas turbine cycle when the fuel cell stack is not working.

Fig. 2 shows another kind of structural form of the present invention, differs from the structural form of Fig. 1 in that the air through the air bypass line (9) first enters the combustion chamber (10) and then flows out from the stack (4) The air passing through the stack air outlet pipeline (20) is mixed with the pipeline (14) and enters the turbine (19).

The electric stack (4) itself has an attached control device, which controls the air flow required by the electric stack, and the flow distribution valve (8) receives the signal from the control device to distribute the air flow between the electric stack and the air bypass pipeline.

Claims (2)

1, hybrid power system for vehicle-use fuel cell gas curbine, contain sources of hydrogen (1), fuel cell pack (4), air compressor (7), turbine (11), integrated electric motor/generator (12), it is characterized in that, also contain by a flow divider valve (8) and be connected one section air by-pass pipeline (9) on the air inlet pipeline of vehicle fuel battery heap (4), the air inlet of described flow divider valve (8) connects the delivery outlet of air compressor (7), an one gas outlet connects the air inlet of described vehicle fuel battery heap (4), its another gas outlet connects the air inlet of described air by-pass pipeline (9), and the gas outlet of described air by-pass pipeline (9) connects the air exhaust duct road of described vehicle fuel battery heap; Also contain a combustion chamber (10), an air inlet of described combustion chamber (10) connects the hydrogen output pipe (17) of described vehicle fuel battery heap (4), common another air inlet that flows into described combustion chamber (10) of air in the air exhaust duct road of described air by-pass pipeline (9) and described vehicle fuel battery heap (4), the gas outlet of described combustion chamber (10) connects the turbine (11) of vehicle fuel battery system.

2, hybrid power system for vehicle-use fuel cell gas curbine, contain sources of hydrogen (1), fuel cell pack (4), air compressor (7), turbine (11), integrated electric motor/generator (12), it is characterized in that, also contain by a flow divider valve (8) and be connected one section air by-pass pipeline (9) on vehicle fuel battery heap (4) air inlet pipeline, the air inlet of described flow divider valve (8) connects the delivery outlet of air compressor (7), an one gas outlet connects the air inlet of described vehicle fuel battery heap (4), and its another gas outlet connects the air inlet of described air by-pass pipeline (9); Also contain a combustion chamber (10), an air inlet of described combustion chamber (10) connects the hydrogen output pipe (17) of described vehicle fuel battery heap (4), its another air inlet connects the outlet of described air by-pass pipeline (9), its outlet connects the air of described vehicle fuel battery heap (4) and gets rid of pipeline, and this air is got rid of the turbine (11) that pipeline connects the vehicle fuel battery system.

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