CN111933977A - Fuel cell-turbocharged internal combustion engine hybrid power generation system - Google Patents

Abstract

The invention proposes a fuel cell-turbocharged internal combustion engine hybrid power generation system. The fuel compressor, desulfurizer, fuel heat exchanger and mixer of the power generation system are connected in sequence, the air compressor is connected to the air heat exchanger, and the reformer is connected to the air heat exchanger. Connected with water vaporizer, mixer and fuel cell anode, fuel cell cathode connected with air heat exchanger, fuel cell cathode connected with air heat exchanger, fuel cell anode connected with mixer and fuel heat exchanger high temperature inlet respectively, internal combustion engine The fuel inlet end is respectively connected with the cooler outlet, the fuel bypass and the air compressor outlet, the working medium output end of the internal combustion engine is connected with the turbine input end, and the internal combustion engine is connected with the engine. The problem of a large amount of fuel remaining in the tail gas of the solid oxide fuel cell and the low combustion efficiency is solved. The invention combines the fuel cell and the internal combustion engine, so that the power generation can be quickly adjusted in a wide range, and more than 70% of the power generation can be achieved. efficiency.

Description

A fuel cell-turbocharged internal combustion engine hybrid power generation system

technical field

The invention relates to a fuel cell-turbocharged internal combustion engine hybrid power generation system, which belongs to the technical field of thermal cycle devices for power generation systems.

Background technique

With the widespread utilization of indirect energy sources such as solar and wind energy, which has brought more and more peak regulation pressure to the grid, in order to achieve optimal efficiency, these load transients must be tracked as closely as possible to avoid wasting energy. Centralized power plants (such as combined cycle power plants), while highly efficient, suffer from inefficiencies in power generation and potential overgeneration-related losses when operating at part load. As a result, more attention has recently been paid to on-site or distributed energy rationing strategies. Distributed generation not only has better variable condition performance, but also can reduce transmission loss, which accounts for about 5-8% of energy loss associated with centralized generation, and fuel cell is an ideal device for distributed generation because it can Efficient power generation is achieved on every scale.

A major challenge encountered in the application of fuel cells is that the output voltage will decrease significantly with the decrease of fuel concentration, so the fuel utilization rate of fuel cells cannot reach a high level, currently generally 55%-70%, This results in a large amount of fuel remaining in the exhaust gas of the fuel cell. At present, the most popular exhaust gas utilization system is a fuel cell gas turbine hybrid power generation system, which replaces the combustion chamber of a traditional gas turbine with a fuel cell. The unused fuel can be burned in the combustion chamber, and finally the gas is expanded in the turbine to do work. The efficiency of the fuel cell gas turbine hybrid power generation system can reach more than 70%; however, the performance under variable conditions is poor and the response time is long, so it is not suitable for the field of distributed power generation that requires frequent changes of operating conditions and rapid start-up.

SUMMARY OF THE INVENTION

In order to solve the problems mentioned in the above background technology, the present invention proposes a novel fuel cell-turbocharged internal combustion engine hybrid power generation system, which combines the fuel cell and the internal combustion engine, so that the generated power can be quickly adjusted in a wide range, and can The power generation efficiency of more than 70% is achieved, and the problem of a large amount of fuel remaining in the tail gas of the solid oxide fuel cell is solved.

The invention proposes a fuel cell-turbocharged internal combustion engine hybrid power generation system, comprising a fuel compressor, a desulfurizer, a fuel heat exchanger, a mixer, a reformer, a water vaporizer, a solid oxide fuel cell, an inverter, a cooling air compressor, air compressor, air heat exchanger, internal combustion engine, engine and turbine, the fuel compressor, desulfurizer, fuel heat exchanger and mixer are connected in sequence, the air compressor is connected with the air heat exchanger, the The gaseous water input end of the reformer is connected with the gaseous water output end of the water vaporizer, the fuel input end of the reformer is connected with the output end of the mixer, and the reformed gas output end of the reformer is connected with the solid oxide The anode channel input end of the fuel cell is connected, the cathode channel input end of the solid oxide fuel cell is connected to the high pressure and high temperature air output end of the air heat exchanger, and the cathode outlet end of the solid oxide fuel cell is connected to the high temperature air end of the air heat exchanger The inlet end is connected, the anode outlet end of the solid oxide fuel cell is respectively connected with the high temperature inlet end of the mixer and the fuel heat exchanger, the fuel inlet end of the internal combustion engine is respectively connected with the outlet of the cooler, the fuel bypass and the outlet of the air compressor, The working medium output end of the internal combustion engine is connected with the turbine input end, and the internal combustion engine is connected with the engine.

Preferably, after the fuel is compressed by the fuel compressor, a part of the fuel flows through the desulfurizer, the fuel heat exchanger and the mixer into the reformer for steam reforming, and electrochemical reaction occurs between the solid oxide fuel cell and the compressed air to produce The electric energy is connected to the grid after frequency conversion by the inverter; the other part enters the fuel bypass and directly leads to the internal combustion engine.

Preferably, part of the anode tail gas of the solid oxide fuel cell is returned to the reformer to provide the required heat and water vapor for the reforming reaction, the remaining fuel enters the fuel heat exchanger to heat the incoming fuel, and the fuel passes through the internal combustion engine before entering the internal combustion engine. The cooler is used for cooling, and the cooling water is vaporized as the raw material for steam reforming. The cooled fuel is mixed with the fuel of the fuel bypass and passed into the internal combustion engine to burn and do work, and drive the engine to generate electricity.

Preferably, after the air is compressed by the air compressor, it enters the solid oxide fuel cell and the internal combustion engine respectively as an oxidant; the solid oxide fuel cell cathode exhaust gas is mixed with the air heat exchanger and the exhaust gas of the internal combustion engine and enters the turbine to expand and perform work, driving the fuel compressor. and air compressor.

Preferably, the internal combustion engine is an eight-cylinder internal combustion engine, which is divided into four groups, each group includes two cylinders, at the same time, the pistons in one group of cylinders are in the intake stroke, the pistons in one group of cylinders are in the compression stroke, and the pistons in one group of cylinders are in the compression stroke, and the pistons in one group of cylinders are in the compression stroke. The pistons are in the power stroke, and the pistons in one group of cylinders are in the exhaust stroke; the two cylinders in each group are in the same state of motion.

Preferably, the internal combustion engine is a homogeneous mixture pressure ignition engine

Preferably, the solid oxide fuel cell adopts anode circulation, and part of the anode tail gas of the solid oxide fuel cell is passed back to the reformer to provide heat and water for the reformer, and the return rate is determined by the heat required by the reformer.

Preferably, the anode tail gas of the solid oxide fuel cell is cooled to 450K with cooling water before passing into the internal combustion engine to reduce the inlet temperature of the internal combustion engine, and the cooling water is passed into the reformer after absorbing heat and gasifying.

The beneficial effects of the fuel cell-turbocharged internal combustion engine hybrid power generation system of the present invention are:

1. The present invention proposes a fuel cell-turbocharged internal combustion engine hybrid power generation system, which combines the fuel cell and the internal combustion engine, so that the unused exhaust gas in the exhaust gas of the fuel cell can be used by the internal combustion engine, and can achieve a power generation efficiency of more than 70%.

2. The present invention proposes a fuel cell-turbocharged internal combustion engine hybrid power generation system, which adds a fuel bypass, which can make the fuel cell work under a stable working condition or a slow fluctuation condition, and adjust the fuel bypass flow to realize the fuel cell-turbine The supercharged internal combustion engine hybrid power generation system can adjust the power generation in a wide range, and the efficiency can be maintained above 55% under frequently changing working conditions, which is suitable for distributed power generation application scenarios and has better adaptability.

3. The present invention proposes a fuel cell-turbocharged internal combustion engine hybrid power generation system, which adds an anode return branch, realizes the self-sufficiency of the heat of the reformer, greatly reduces the demand for water of the reformer, and improves the efficiency of the reformer. The fuel concentration at the inlet of the internal combustion engine increases the efficiency of the internal combustion engine by 5% and reduces CO emissions by 50%.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

In the accompanying drawings: FIG. 1 is a schematic diagram of the fuel cell-turbocharged internal combustion engine hybrid power generation system according to the present invention;

Of which: 1- fuel compressor, 2- desulfurizer, 3- fuel heat exchanger, 4- mixer, 5- reformer, 6- vaporizer, 7- solid oxide fuel cell, 8- inverter, 9 -cooler, 10-air compressor, 11-air heat exchanger, 12-internal combustion engine, 13-engine, 14-turbine; solid line represents fuel passage, thick dashed line in upper left corner represents fuel bypass, thin dashed line represents air passage, The dot-dash line represents the exhaust gas passage, and the dotted box represents the power passage.

Detailed ways

The specific embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings:

Embodiment 1: This embodiment is described with reference to FIG. 1 . The fuel cell-turbocharged internal combustion engine hybrid power generation system described in this embodiment includes a fuel compressor 1, a desulfurizer 2, a fuel heat exchanger 3, a mixer 4, a reformer 5, a water vaporizer 6, and a solid oxide fuel. Battery 7, Inverter 8, Cooler 9, Air Compressor 10, Air Heat Exchanger 11, Internal Combustion Engine 12, Engine 13 and Turbine 14, the Fuel Compressor 1, Desulfurizer 2, Fuel Heat Exchanger 3 and Mixer The air compressor 10 is connected to the air heat exchanger 11 in sequence, the gaseous water input end of the reformer 5 is connected to the gaseous water output end of the water vaporizer 6, and the fuel input end of the reformer 5 is connected. The end is connected to the output end of the mixer 4, the reformed gas output end of the reformer 5 is connected to the anode channel input end of the solid oxide fuel cell 7, and the cathode channel input end of the solid oxide fuel cell 7 is connected to the The high pressure and high temperature air output end of the air heat exchanger 11 is connected, the cathode outlet end of the solid oxide fuel cell 7 is connected to the high temperature inlet end of the air heat exchanger 11, and the anode outlet end of the solid oxide fuel cell 7 is respectively connected to the mixer 4 is connected to the high temperature inlet end of the fuel heat exchanger 3, the fuel inlet end of the internal combustion engine 12 is respectively connected to the outlet of the cooler 9, the fuel bypass and the outlet of the air compressor 10, and the output end of the working medium of the internal combustion engine 12 is connected to the turbine 14 input connection.

After the fuel is compressed by the fuel compressor 1, a part of the fuel flows through the desulfurizer 2, the fuel heat exchanger 3 and the mixer 4 and enters the reformer 5 for steam reformation. Reacting to generate electric energy, which is connected to the power grid after frequency conversion by the inverter 8; A part of the fuel is passed into the fuel cell system, and a part is passed directly into the internal combustion engine. Under the condition of variable load, the fuel flow of the internal combustion engine 12 is changed, and the internal combustion engine 12 bears the variable load.

A part of the anode tail gas of the solid oxide fuel cell 7 is returned to the reformer 5 to provide the required heat and water vapor for the reforming reaction, and the remaining fuel enters the fuel heat exchanger 3 to heat the incoming fuel. Before the fuel enters the internal combustion engine 12 It is cooled by the cooler 9, and the cooling water is vaporized and used as the raw material for steam reforming. The cooled fuel is mixed with the fuel of the fuel bypass and passed into the internal combustion engine 12 to burn and perform work, thereby driving the engine 13 to generate electricity.

After the air is compressed by the air compressor 10, it enters the solid oxide fuel cell 7 and the internal combustion engine 12 respectively to be an oxidant; the solid oxide fuel cell 7 cathode tail gas is mixed by the air heat exchanger 11 and the tail gas of the internal combustion engine 12 and enters the turbine 14 to expand and do work, The fuel compressor 1 and the air compressor 10 are driven.

The internal combustion engine 12 employs a Homogeneous Hybrid Pressure Ignition Ignition (HCCI) engine. The internal combustion engine 12 is an eight-cylinder internal combustion engine, divided into four groups, each group includes two cylinders, at the same time, the pistons in one group of cylinders are in the intake stroke, the pistons in one group of cylinders are in the compression stroke, and the pistons in one group of cylinders are in the inhalation stroke. On the power stroke, the pistons in one group of cylinders are in the exhaust stroke; the two cylinders in each group are in the same state of motion.

The solid oxide fuel cell 7 adopts anode circulation, and part of the anode exhaust gas of the solid oxide fuel cell 7 is passed back to the reformer 5 to provide heat and water for the reformer 5 , and the return rate is determined by the heat required by the reformer 5 . The fuel cell system adopts anode circulation, and 60%-70% of the tail gas of the fuel cell anode is re-introduced to the reformer 5 according to the needs, so as to provide water and sufficient heat for steam reforming.

Before the solid oxide fuel cell 7 anode tail gas is passed into the internal combustion engine, cooling water is used to cool to 450K to reduce the inlet temperature of the internal combustion engine 12, and the cooling water is passed into the reformer 5 after absorbing heat and gasifying.

The fuel and air introduced into the fuel cell 7 and the internal combustion engine 12 are compressed by the compressor to increase the working pressure of the fuel cell 7 and the internal combustion engine 12, and the exhaust gas pushes the turbine 14 to do work to provide energy for the compressor.

The fuel output end of the fuel compressor is divided into two branches, the first branch is connected to the fuel input end of the internal combustion engine 12 , and the second branch is connected to the cathode air heat exchanger 11 of the fuel cell 7 .

The specific operation process and working principle of the fuel cell-turbocharged internal combustion engine hybrid power generation system of the present invention are as follows:

The fuel is first compressed by the fuel compressor 1, and then desulfurized by the desulfurizer 2 to avoid damage to the electrode plates of the fuel cell. After the fuel is desulfurized, the fuel is heated to the temperature required for reforming by the fuel heat exchanger 3, and mixed with the exhaust gas of the fuel cell anode. The reformer 5 carries out steam reforming reaction, and the reformed fuel is passed into the anode of the solid oxide fuel cell 7 for electrochemical oxidation reaction to generate electric energy, which is connected to the power grid after frequency conversion by the inverter 8, and part of the anode tail gas is returned to the heavy metal. In the reformer 5, the required heat and water vapor are provided for the reforming reaction, and the remaining fuel enters the fuel heat exchanger 3 to heat the incoming fuel, and the fuel is cooled before entering the internal combustion engine 12, and the cooling water is vaporized as a steam reformer. The raw material, the cooled fuel and the fuel of the fuel bypass are mixed and passed into the internal combustion engine 12 to burn and do work, and drive the engine 13 to generate electricity; on the other hand, the air is compressed by the air compressor 10, and a part of it is passed into the internal combustion engine 12 to provide oxygen for combustion, The other part enters the air heat exchanger 11 for heating, and then passes into the cathode of the fuel cell 7 to do the oxidant for electrochemical reaction, and the air at the cathode outlet enters the air heat exchanger 11 to heat the incoming air; After the air at the outlet is mixed, it enters the turbine 14 for expansion and work, and drives the two compressors.

The fuel cell-turbocharged internal combustion engine hybrid power generation system adds a fuel bypass, and the fuel passed into the internal combustion engine 12 can be the fuel cell anode exhaust gas or the unreacted fuel. When the system load changes, the fuel bypass can be adjusted by adjusting the fuel bypass. The road flow ensures that the load of the fuel cell 7 changes slowly, and the internal combustion engine 12 realizes dynamic adjustment, which solves the problem of slow dynamic response of the fuel cell, and enables the system to achieve rapid adjustment in a wide range.

The fuel cell-turbocharged internal combustion engine hybrid power generation system adds an anode circulation loop. According to the requirement of the reformer to absorb heat, 60%-70% of the fuel cell anode exhaust gas is recirculated to the reformer, so that the heat of the reformer can be realized. It is self-sufficient, reducing the demand for water, and at the same time increasing the fuel concentration at the inlet of the internal combustion engine, improving the performance of the internal combustion engine.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention, and may also be a reasonable combination of the features recorded in the above-mentioned various embodiments, all within the spirit and principle of the present invention, Any modification, equivalent replacement, improvement, etc. made should be included within the protection scope of the present invention.

Claims (8)

1. A fuel cell-turbocharged internal combustion engine hybrid power generation system is characterized by comprising a fuel compressor (1), a desulfurizer (2), a fuel heat exchanger (3), a mixer (4), a reformer (5), a water vaporizer (6), a solid oxide fuel cell (7), an inverter (8), a cooler (9), an air compressor (10), an air heat exchanger (11), an internal combustion engine (12), an engine (13) and a turbine (14),

the fuel gas compressor (1), the desulfurizer (2), the fuel heat exchanger (3) and the mixer (4) are sequentially connected, the air gas compressor (10) is connected with the air heat exchanger (11), the gaseous water input end of the reformer (5) is connected with the gaseous water output end of the water vaporizer (6), the fuel input end of the reformer (5) is connected with the output end of the mixer (4), the reformed gas output end of the reformer (5) is connected with the anode channel input end of the solid oxide fuel cell (7), the cathode channel input end of the solid oxide fuel cell (7) is connected with the high-pressure high-temperature air output end of the air heat exchanger (11), the cathode outlet end of the solid oxide fuel cell (7) is connected with the high-temperature inlet end of the air heat exchanger (11), the anode outlet end of the solid oxide fuel cell (7) is respectively connected with the high-temperature inlet ends of the mixer (4) and the fuel heat exchanger (3), the solid oxide fuel cell (7) is connected with the inverter (8), the fuel inlet end of the internal combustion engine (12) is respectively connected with the outlet of the cooler (9), the fuel bypass and the outlet of the air compressor (10), the working medium output end of the internal combustion engine (12) is connected with the input end of the turbine (14), and the internal combustion engine (12) is connected with the engine (13).

2. The fuel cell-turbocharged internal combustion engine hybrid power generation system according to claim 1, wherein after the fuel is compressed by the fuel compressor (1), a part of the fuel flows through the desulfurizer (2), the fuel heat exchanger (3) and the mixer (4) and enters the reformer (5) for steam reforming, and after the electrochemical reaction between the solid oxide fuel cell (7) and the compressed air occurs, the electric energy is generated, and after the frequency conversion by the inverter (8), the electric energy is connected to the power grid; the other part enters a fuel bypass and directly leads into the internal combustion engine (12).

3. The fuel cell-turbocharged internal combustion engine hybrid power generation system according to claim 2, wherein a part of the anode tail gas of the solid oxide fuel cell (7) flows back to the reformer (5) to provide heat and steam required for the reforming reaction, the remaining fuel enters the fuel heat exchanger (3) to heat the incoming fuel, the fuel is cooled by the cooler (9) before entering the internal combustion engine (12), the cooled water is gasified and then used as the raw material for steam reforming, and the cooled fuel and the fuel bypassed by the fuel are mixed and introduced into the internal combustion engine (12) to be combusted and used as work to drive the engine (13) to generate power.

4. The fuel cell-turbocharged internal combustion engine hybrid power generation system according to claim 1, wherein air is compressed by the air compressor (10) and then enters the solid oxide fuel cell (7) and the internal combustion engine (12) as oxidants respectively; the tail gas of the cathode of the solid oxide fuel cell (7) is mixed with the tail gas of the internal combustion engine (12) through the air heat exchanger (11) and then enters the turbine (14) to do work through expansion, so that the fuel compressor (1) and the air compressor (10) are driven.

5. The fuel cell-turbocharged internal combustion engine hybrid power generation system according to claim 1, wherein the internal combustion engine (12) is an eight-cylinder internal combustion engine, divided into four groups, each group comprising two cylinders, and at the same time, the pistons in one group of cylinders are in the intake stroke, the pistons in one group of cylinders are in the compression stroke, the pistons in one group of cylinders are in the power stroke, and the pistons in one group of cylinders are in the exhaust stroke; the two cylinders in each group are in the same motion state.

6. The fuel cell-turbocharged internal combustion engine hybrid power generation system according to claim 1, wherein the internal combustion engine is a homogeneous charge compression ignition engine.

7. The fuel cell-turbocharged internal combustion engine hybrid power generation system according to claim 1, wherein the solid oxide fuel cell (7) employs an anode cycle, and a part of the anode tail gas of the solid oxide fuel cell (7) is returned to the reformer (5) to provide heat and water for the reformer (5), and the return rate is determined by the heat required by the reformer (5).

8. The fuel cell-turbocharged internal combustion engine hybrid power generation system according to claim 1, wherein the anode exhaust of the solid oxide fuel cell (7) is cooled to 450K using cooling water before being introduced into the internal combustion engine, the inlet temperature of the internal combustion engine (12) is reduced, and the cooling water is introduced into the reformer (5) after being vaporized by heat absorption.

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