Power system based on hydrogen production by cracking and high-low pressure combined injection and its operation method

Abstract

The present invention relates to a power system based on hydrogen production by cracking and high-low pressure combined injection and its operation method, and belongs to the field of power energy technology. The problem that the ignition temperature and pressure of ammonia fuel are too high, making it difficult to use, is solved. It includes a plasma catalytic ammonia cracking reforming module and an internal combustion engine cylinder module, wherein the plasma catalytic ammonia cracking reforming module is connected to the internal combustion engine cylinder module, the plasma catalytic ammonia cracking reforming module is used to realize the catalysis of the fuel, and the internal combustion engine cylinder module is used to ignite the fuel to do work. The plasma catalytic ammonia cracking reforming module of the present invention converts ammonia gas, which is more difficult to burn, into hydrogen gas with a wider ignition limit on-site during the fuel supply stage by partially cracking and reforming pure ammonia to produce hydrogen, thereby forming hydrogen-rich ammonia gas with lower combustion boundary conditions, and eliminating the difficulty of hydrogen storage and transportation in the direct hydrogen blending combustion-aiding method, making it possible to use ammonia fuel as a zero-carbon new energy source in power devices.

Description

Technical Field

[0001] The invention relates to a power system based on hydrogen production by cracking and high and low pressure combination and an operation method thereof, belonging to the technical field of power energy. Background Art

[0002] CO2 emission standards are becoming increasingly stringent. Internal combustion engines are widely used in various national production fields and are the main source of carbon emissions. The power density, safety and reliability of the engine make it irreplaceable. In this context, in order to effectively control the greenhouse effect and reduce greenhouse gas emissions, it is crucial to find clean alternative energy in the field of internal combustion engines, and the development of zero-carbon power technology is imperative.

[0003] Hydrogen and ammonia are currently widely recognized zero-carbon fuels. Hydrogen has many advantages as an engine fuel, such as wide ignition margin, high thermal efficiency, low emissions, good economy, and wide sources. However, the physical and chemical properties of hydrogen lead to difficulties in storage, high cost, low output power, high NOx emissions, and problems such as detonation, pre-ignition, and flashback caused by abnormal combustion. Compared with hydrogen, ammonia is easier to control and operate. Pure ammonia has a lower laminar combustion velocity, higher ignition energy and auto-ignition temperature than traditional fossil fuels, and is more difficult to burn as a pure fuel.

[0004] Hydrogen is more chemically active than ammonia. Some studies have shown that adding an appropriate amount of hydrogen to pure ammonia fuel can significantly increase the overall reactivity of the fuel, thereby solving the problem of direct combustion of pure ammonia fuel in the cylinder. Ammonia is a hydrogen-rich substance with a theoretical hydrogen storage capacity of up to 17.6wt%, good thermal stability, and mild hydrogen release conditions. It can be used as a hydrogen storage material and converted into hydrogen during the fuel supply stage to reduce the in-cylinder combustion conditions of ammonia fuel. Therefore, it is particularly important to achieve on-site hydrogen production and blending through raw material cracking and reforming.

[0005] Thermal cracking ammonia reforming to produce hydrogen is the most common form of conversion, and the high-temperature exhaust gas of the engine serves as the heat source for the reaction. However, the performance of the hydrogen production system using waste heat cannot meet the required hydrogen supply rate, because ammonia requires at least about 20% hydrogen mixing ratio to achieve a laminar flame speed equivalent to that of methane. Plasma is a collection of charged positive and negative ions, free radicals and various excited neutral particles, and is called the "fourth state of matter". The high-energy particles in the plasma can destroy the nitrogen-hydrogen bonds in NH3, and crack and reform the large molecule ammonia into small molecule hydrogen under relatively high temperature environment. Gliding arc discharge is a common form of gas discharge that produces periodic sliding arcs. The sliding arc discharge exciter has a simple structure and low power consumption, and has the advantages of both thermal equilibrium / non-equilibrium plasma.

[0006] The in-cylinder high-pressure direct injection liquid ammonia mode is to inject the fuel once or in small amounts of liquid ammonia multiple times at a certain angle at the end of the compression stroke directly into the cylinder for combustion. This method can simplify the cylinder structure, but the physical and chemical properties of ammonia fuel determine that its ignition pressure reaches 38MPa or even higher, which is difficult to achieve under the current strength conditions of internal combustion engines.

[0007] Therefore, it is urgent to propose a power system based on cracking hydrogen production and high- and low-pressure combined injection and its operation method to solve the above-mentioned technical problems. Summary of the invention

[0008] The purpose of the present invention is to solve the problem that the ignition temperature and pressure of ammonia fuel are too high to make it difficult to apply, and to provide a power system based on cracking hydrogen production and high-low pressure combined injection and its operation method. A brief overview of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to determine the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0009] The technical solution of the present invention:

[0010] A power system based on cracking hydrogen production and high-low pressure combined injection includes a plasma catalytic ammonia cracking reforming module and an internal combustion engine cylinder module. The plasma catalytic ammonia cracking reforming module is connected to the internal combustion engine cylinder module. The plasma catalytic ammonia cracking reforming module is used to realize the catalysis of fuel, and the internal combustion engine cylinder module is used to ignite the fuel to perform work.

[0011] Preferably: the plasma catalytic ammonia cracking reforming module includes an ammonia inlet, a hydrogen-ammonia reforming mixed gas outlet, a plasma generator, cracking heating tubes and a catalyst shell, and the two ends of the catalyst shell are provided with an ammonia inlet and a hydrogen-ammonia reforming mixed gas outlet, a plasma generator is arranged in the middle and upper part of the catalyst shell, and the catalyst shell is provided with evenly arranged cracking heating tubes.

[0012] Preferably: the internal combustion engine cylinder module includes a hydrogen-ammonia mixture injection valve, a liquid ammonia injection valve, an igniter, a pre-combustion chamber, a piston, a scavenging port, an exhaust port plunger, an exhaust port and a cylinder body, a piston is slidably arranged in the cylinder body, a scavenging port is arranged at the lower part of the side of the cylinder body, a mixture input pipe connected to the inside of the cylinder body is arranged in the middle part of the side of the cylinder body, a hydrogen-ammonia mixture injection valve is arranged on the mixture input pipe, a pre-combustion chamber, a liquid ammonia injection valve and an exhaust port are arranged on the top of the cylinder body, the cylinder body is connected to the pre-combustion chamber through a plurality of small holes, and a A liquid ammonia input pipe is connected to the inside of the cylinder body, and a liquid ammonia injection valve is arranged on the liquid ammonia input pipe. An igniter is arranged in the pre-combustion chamber. One end of the exhaust port plunger and the plunger sleeve form a plunger pair. The crankshaft is connected to the cylinder body through a connecting rod bearing. The other end of the exhaust port plunger extends into the cylinder body to establish a match with the exhaust port. A piston ring is arranged between the side wall of the piston and the inner wall of the cylinder body. The drive of the piston can adopt the crank-connecting rod structure of the internal combustion engine, that is, the lower part of the piston is hinged to one end of the connecting rod, the other end of the connecting rod is connected to the crankshaft through a bearing, the crankshaft is connected to the motor, and the motor is fixedly connected to the internal combustion engine frame.

[0013] Preferably: the low-pressure injection valve is used for the hydrogen-ammonia mixture low-pressure injection valve, and the high-pressure direct injection valve is used for the liquid ammonia high-pressure direct injection valve.

[0014] Preferably: the plasma catalytic ammonia cracking reforming module also includes a heating exhaust gas inlet and an exhaust gas outlet, and the two ends of the cracking heating tube have a heating exhaust gas inlet and an exhaust gas outlet, the heating exhaust gas inlet and the exhaust gas outlet extend from the catalyst housing, the exhaust port is connected to the heating exhaust gas inlet, and the exhaust gas outlet is connected to the inlet of the exhaust gas post-treatment device.

[0015] Preferably: it also includes an ammonia intake diverter valve and a hydrogen-rich gas mixing valve, the ammonia source is connected to the ammonia inlet and the inlet of the hydrogen-rich gas mixing valve through the ammonia intake diverter valve, the hydrogen-ammonia reforming mixed gas outlet is connected to the inlet of the hydrogen-rich gas mixing valve, the outlet of the hydrogen-rich gas mixing valve is connected to the hydrogen-ammonia mixed gas injection valve, the ammonia source is used to provide ammonia, the present invention can be applied to the field of high-power internal combustion engine equipment to achieve zero-carbon power.

[0016] The power system operation method based on hydrogen production by cracking and high-low pressure combined injection comprises the following steps:

[0017] Step 1: Liquid ammonia is vaporized into ammonia gas through a vaporizer and then split through an ammonia gas inlet splitter valve. One part enters the catalyst housing through the reformer ammonia gas inlet, and the other part directly flows to the hydrogen-rich gas mixing valve;

[0018] Step 2: Start the heating tubes, after ammonia flows into the catalyst shell of the cracking and reforming area, the sliding arc discharge exciter in the plasma generator discharges to generate plasma in the area (inside the catalyst shell), and under the catalytic action of the high-speed and high-energy plasma, part of the ammonia around the cracking heating tubes is heated and catalytically cracked into hydrogen to form hydrogen-rich gas;

[0019] Step 3: The reformed hydrogen-rich gas flows to the hydrogen-rich gas mixing valve, and is mixed with another part of ammonia to form a hydrogen-ammonia mixed gas, and the hydrogen-ammonia mixed gas flows to the ammonia-hydrogen mixed gas injection valve;

[0020] Step 4: The working mechanism of the zero-carbon power system is a two-stroke pre-ignition piston internal combustion engine, which burns and works in a high-low pressure combined injection mode as the piston 13 moves; in the downward stage of the piston, when the upper end surface of the piston is lower than the upper edge of the scavenging port, air enters the cylinder through the scavenging port until the piston passes the bottom dead center (the lowest position of the piston movement), and then the piston moves upward, and the scavenging is completed when the lower end surface of the piston is higher than the upper edge of the scavenging port; the motor drives the piston upward for the first time through the crankshaft crank structure, and the subsequent upward movement is completed by inertia;

[0021] Step 5: The hydrogen-ammonia mixture is injected into the cylinder body through the hydrogen-ammonia mixture injection valve in the early and middle stages of the compression stroke when the piston is located between the mixture injection valve and the air through the scavenging port. The disturbance caused by the upward movement of the piston causes the gas in the cylinder to mix and form a combustible mixture.

[0022] Step six: After the piston position is higher than the hydrogen-ammonia mixture injection valve, it will no longer be injected through this valve. During the upward process, the combustible mixture in the cylinder body is gradually compressed and heated, and its reaction activity gradually increases. The mixture enters and fills the pre-combustion chamber.

[0023] Step 7: At the end of the compression stroke, the piston is located above the mixture injection valve, and the liquid ammonia fuel is injected into the cylinder body at high pressure by the liquid ammonia injection valve according to a certain injection rule. After the droplets are broken and vaporized, they are mixed with the combustible mixture to form a fuel mixture.

[0024] Step 8: The igniter inside the pre-combustion chamber acts at a certain moment before the piston reaches the highest position of the piston movement at the top dead center. The igniter emits an electric spark to ignite the lean combustible gas with a relatively low equivalence ratio in the pre-combustion chamber. After ignition, the flame front enters the cylinder body through multiple small holes connecting the pre-combustion chamber and the cylinder body. Each small hole corresponds to an ignition point. The multiple ignition points quickly ignite the combustible gas (fuel mixture) in the cylinder body. The gas in the cylinder body quickly burns and expands. After the piston passes the top dead center, it is pushed by the expanding gas to do work.

[0025] Step 9: When combustion ends, the exhaust port plunger opens the exhaust port, and the exhaust gas in the cylinder body is discharged from the exhaust port.

[0026] Preferably: in step 2, the high-temperature exhaust gas generated after combustion enters the cracking heating tube through the exhaust port and the heating exhaust gas inlet, and exchanges heat with the ammonia in the catalyst shell, and is discharged to the external environment or the exhaust gas post-treatment device through the exhaust gas outlet after heat exchange.

[0027] The present invention has the following beneficial effects:

[0028] 1. The plasma catalytic ammonia cracking and reforming module of the present invention converts ammonia gas, which is difficult to burn, into hydrogen gas with a wide ignition limit on site during the fuel supply stage by partially cracking and reforming pure ammonia to produce hydrogen, thereby forming hydrogen-rich ammonia gas with low combustion boundary conditions, so as to solve the problem of excessively high ignition temperature and pressure of pure ammonia fuel, and eliminate the difficulty of hydrogen storage and transportation in the direct hydrogen blending combustion-supporting method, making it possible to use ammonia fuel as a zero-carbon new energy in power plants. Compared with the direct pyrolysis method, the plasma catalytic cracking and reforming of the present invention can effectively reduce the reaction temperature and conversion rate, and at the same time reduce the energy consumption of ammonia reforming hydrogen production;

[0029] 2. The present invention adopts a combined injection method of high-pressure direct injection of liquid ammonia in the cylinder and low-pressure injection of hydrogen-ammonia mixed gas. In the early and middle stages of the compression stroke, a low-pressure injection valve of hydrogen-ammonia mixed gas is passed through the side of the cylinder body, so that a certain proportion of hydrogen-rich ammonia gas enters the cylinder in advance and is fully mixed with the gas in the cylinder under the disturbance of the piston upward movement. At the same time, the combustible mixed gas in the cylinder is compressed and heated to perform low-temperature combustion, and the gas activity is improved, thereby reducing the ignition boundary and the maximum explosion pressure in the cylinder under the liquid ammonia direct injection method;

[0030] 3. The pre-combustion ignition method adopted by the present invention can reduce the size of the igniter and can realize accurate control of the ignition time through the igniter; the setting of the pre-combustion chamber can limit the ignition environment to the environment of the combustible gas with a lower equivalent ratio, which is convenient for ignition. The flame front formed after the igniter releases an electric spark to ignite the lean mixture in the pre-combustion chamber enters the cylinder through multiple small holes connecting the pre-combustion chamber and the cylinder. Multiple ignition points make the combustible gas in the cylinder burn more quickly and fully, thereby improving the economy and power of the system;

[0031] 4. Most of the heat required by the plasma catalytic ammonia cracking reforming module of the present invention comes from the high-temperature exhaust gas discharged after the internal combustion engine works, so that the waste heat of the cylinder exhaust gas can be recycled, the thermal efficiency and energy utilization rate of the fuel are improved, and energy conservation and emission reduction are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of a power system based on hydrogen production by cracking and high- and low-pressure combined injection.

[0033] In the figure: 1-ammonia inlet diverter valve, 2-ammonia inlet, 3-hydrogen-ammonia reforming mixed gas outlet, 4-plasma generator, 5-heating exhaust gas inlet, 6-exhaust gas outlet, 7-cracking heating tubes, 8-hydrogen-rich gas mixing valve, 9-hydrogen-ammonia mixed gas injection valve, 10-liquid ammonia injection valve, 11-igniter, 12-precombustion chamber, 13-piston, 14-scavenging port, 15-exhaust port plunger. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0035] Specific implementation method 1: Combination Figure 1 The present embodiment is described. The power system based on cracking hydrogen production and high- and low-pressure combined injection of the present embodiment includes a plasma catalytic ammonia cracking reforming module and an internal combustion engine cylinder module. The plasma catalytic ammonia cracking reforming module is connected to the internal combustion engine cylinder module. The plasma catalytic ammonia cracking reforming module is used to realize the catalysis of the fuel, and the internal combustion engine cylinder module is used to ignite the fuel to do work. After partial catalytic cracking of ammonia to produce hydrogen, a relatively high-activity ammonia-hydrogen mixture can be obtained. In this way, a part of the ammonia fuel is injected into the cylinder in the form of pneumatic injection in the early and middle stages of the compression stroke, which can significantly improve the reaction activity in the cylinder during the intake process, thereby reducing the combustion conditions of the high-pressure direct injection ammonia in the cylinder to meet the strength conditions.

[0036] Specific implementation method 2: Combination Figure 1The present embodiment is described. The power system based on hydrogen production by cracking and high-low pressure combined injection in the present embodiment, the plasma catalytic ammonia cracking reforming module comprises an ammonia inlet 2, a hydrogen-ammonia reforming mixed gas outlet 3, a plasma generator 4, a cracking heating tube 7 and a catalyst shell, and the two ends of the catalyst shell have an ammonia inlet 2 and a hydrogen-ammonia reforming mixed gas outlet 3, a plasma generator 4 is arranged in the middle and upper part of the catalyst shell, and the plasma generator is but not limited to the sliding arc discharge form, and the catalyst shell is provided with uniformly arranged cracking heating tubes 7; the plasma catalyst of the present invention The chemical ammonia cracking and reforming module produces hydrogen by partially cracking and reforming pure ammonia, converting ammonia, which is difficult to burn, into hydrogen with a wider ignition limit on-site during the fuel supply stage, forming hydrogen-rich ammonia with lower combustion boundary conditions, so as to solve the problems of excessively high ignition temperature and pressure of pure ammonia fuel, and eliminate the difficult problem of hydrogen storage and transportation in the direct hydrogen blending and combustion-aiding method, making it possible to use ammonia fuel as a zero-carbon new energy in power plants. Compared with direct pyrolysis, the present invention uses plasma catalytic cracking and reforming to effectively reduce the reaction temperature and conversion rate, while reducing the energy consumption of ammonia reforming to produce hydrogen.

[0037] Specific implementation method three: Combination Figure 1The present embodiment is described. The power system based on hydrogen production by cracking and high-low pressure combined injection of the present embodiment, the internal combustion engine cylinder module includes a hydrogen-ammonia mixture injection valve 9, a liquid ammonia injection valve 10, an igniter 11, a pre-combustion chamber 12, a piston 13, a scavenging port 14, an exhaust port plunger 15, an exhaust port 16 and a cylinder body. The piston 13 is slidably arranged in the cylinder body, the scavenging port 14 is arranged at the lower part of the side of the cylinder body, the middle part of the side of the cylinder body is arranged with a mixture input pipe connected with the inside of the cylinder body, the hydrogen-ammonia mixture injection valve 9 is arranged on the mixture input pipe, and the cylinder body is arranged on the top There are a pre-combustion chamber 12, a liquid ammonia injection valve 10, and an exhaust port 16. The cylinder body is connected to the pre-combustion chamber 12 through a plurality of small holes. A liquid ammonia input pipe connected to the inside of the cylinder body is arranged on the cylinder body, and a liquid ammonia injection valve 10 is arranged on the liquid ammonia input pipe. An igniter 11 is arranged in the pre-combustion chamber 12. The pre-combustion ignition method adopted can reduce the size of the igniter. The flame front formed after the igniter releases an electric spark to ignite the lean mixture in the pre-combustion chamber enters the cylinder through a plurality of small holes connected between the pre-combustion chamber and the cylinder. The plurality of ignition points make the combustible gas in the cylinder burn more quickly and fully, thereby improving the economy and efficiency of the system. Power, the exhaust port plunger 15 is installed at the exhaust port 16, the exhaust port plunger 15 is combined with the plunger sleeve to form a plunger pair, the integrated electronic control system is electrically connected to the plunger pair to control the power on and off, and the power is turned on to generate electromagnetic, the exhaust port plunger 15 moves upward to achieve the sealing of the exhaust port 16, the crankshaft is connected through the connecting rod bearing cylinder body, the other end of the exhaust port plunger 15 extends into the cylinder body to establish a match with the exhaust port 16, a piston ring is arranged between the side wall of the piston 13 and the inner wall of the cylinder body, and the piston can be driven by the crank-connecting rod structure of the internal combustion engine, that is, the lower part of the piston 13 is hinged to one end of the connecting rod, The other end of the connecting rod is connected to the crankshaft through a bearing; the crankshaft can be connected to the motor, and the motor is fixedly connected to the internal combustion engine frame; the present invention adopts a method of combined injection of liquid ammonia high-pressure direct injection and hydrogen-ammonia mixed gas low-pressure injection in the cylinder (inside the cylinder body), and a hydrogen-ammonia mixed gas low-pressure injection valve is passed through the side of the cylinder body in the early and middle stages of the compression stroke, so that a certain proportion of hydrogen-rich ammonia enters the cylinder in advance and is fully mixed with the gas in the cylinder under the disturbance of the upward movement of the piston. At the same time, the combustible mixture in the cylinder is compressed and heated to perform low-temperature combustion, the gas activity is improved, and the ignition boundary under the liquid ammonia direct injection method and the maximum explosion pressure in the cylinder are reduced.

[0038] Specific implementation method four: Combination Figure 1 To illustrate this embodiment, the power system of this embodiment is based on hydrogen production by cracking and high- and low-pressure combined injection. The hydrogen-ammonia mixture low-pressure injection valve 9 adopts a low-pressure injection valve, and the liquid ammonia high-pressure direct injection valve 10 adopts a high-pressure direct injection valve.

[0039] Specific implementation method five: Combination Figure 1The present embodiment is described. The power system of the present embodiment is based on cracking hydrogen production and high-low pressure combined injection. The plasma catalytic ammonia cracking reforming module also includes a heating exhaust gas inlet 5 and an exhaust gas outlet 6. The two ends of the cracking heating tube 7 are provided with a heating exhaust gas inlet 5 and an exhaust gas outlet 6. The heating exhaust gas inlet 5 and the exhaust gas outlet 6 extend from the catalyst housing. The exhaust port 16 is connected to the heating exhaust gas inlet 5, and the exhaust gas outlet 6 is connected to the inlet of the exhaust gas post-treatment device. Most of the heat required by the plasma catalytic ammonia cracking reforming module of the present invention comes from the high-temperature exhaust gas discharged after the cylinder module of the internal combustion engine does work, so that the waste heat of the exhaust gas can be recycled, thereby improving the thermal efficiency and energy utilization rate of the fuel, which is in line with the development concept of energy conservation and emission reduction.

[0040] Specific implementation method six: Combination Figure 1 To illustrate this embodiment, the power system based on cracking hydrogen production and high- and low-pressure combined injection of this embodiment also includes an ammonia intake diverter valve 1 and a hydrogen-rich gas mixing valve 8. The ammonia source is connected to the ammonia inlet 2 and the inlet of the hydrogen-rich gas mixing valve 8 through the ammonia intake diverter valve 1, the hydrogen-ammonia reforming mixed gas outlet 3 is connected to the inlet of the hydrogen-rich gas mixing valve 8, and the outlet of the hydrogen-rich gas mixing valve 8 is connected to the hydrogen-ammonia mixture injection valve 9. The ammonia source is used to provide ammonia. The present invention can be applied to the field of high-power internal combustion engine equipment to achieve zero-carbon power. Under the background of "dual carbon", ammonia fuel is used to replace traditional fossil fuels and low-carbon fuels such as LNG as an energy source in internal combustion engines, so as to achieve true zero-carbon emissions of the power system while taking into account the performance of the device.

[0041] Specific implementation method seven: Combination Figure 1 This embodiment is described. The method for operating a power system based on hydrogen production by cracking and high-low pressure combined injection in this embodiment adopts the power system based on hydrogen production by cracking and high-low pressure combined injection, and includes the following steps:

[0042] Step 1: Liquid ammonia is vaporized into ammonia gas by the vaporization device and then split by the ammonia gas inlet splitter valve 1. One part enters the catalyst housing through the reformer ammonia gas inlet 2, and the other part directly flows to the hydrogen-rich gas mixing valve 8;

[0043] Step 2: Start the heating tubes 7, after ammonia flows into the catalyst shell of the cracking and reforming area, the sliding arc discharge exciter in the plasma generator 4 discharges to generate plasma in the area (inside the catalyst shell), and under the catalytic action of the high-speed and high-energy plasma, part of the ammonia around the cracking heating tubes 7 is heated and catalytically cracked into hydrogen to form hydrogen-rich gas;

[0044] Step 3: The reformed hydrogen-rich gas flows to the hydrogen-rich gas mixing valve 8, and is mixed with another part of ammonia gas to form a hydrogen-ammonia mixed gas, and the hydrogen-ammonia mixed gas flows to the ammonia-hydrogen mixed gas injection valve 9;

[0045] Step 4: The working mechanism of the zero-carbon power system is a two-stroke pre-ignition piston internal combustion engine, which burns and works in a high-low pressure combined injection mode as the piston 13 moves; in the downward stage of the piston 13, when the upper end surface of the piston 13 is lower than the upper edge of the scavenging port 14, air enters the cylinder through the scavenging port 14 until the piston 13 passes the bottom dead center (the lowest position of the piston movement), and then the piston 13 moves upward, and the scavenging is completed when the lower end surface of the piston 13 is higher than the upper edge of the scavenging port 14; the motor drives the piston 13 upward for the first time through the crankshaft crank structure of the internal combustion engine, and the subsequent upward movement is completed by inertia;

[0046] Step 5: The hydrogen-ammonia mixture is injected into the cylinder body through the hydrogen-ammonia mixture injection valve 9 in the early and middle stages of the compression stroke when the piston is located between the mixture injection valve and the air through the scavenging port. The disturbance caused by the upward movement of the piston 13 causes the gas in the cylinder to mix and form a combustible mixture.

[0047] Step 6: After the piston 13 is positioned above the hydrogen-ammonia mixture injection valve 9, it is no longer injected through this valve. During the upward process, the combustible mixture in the cylinder body is gradually compressed and heated, and its reaction activity is gradually increased. The mixture enters and fills the pre-combustion chamber 12; the small holes in the pre-combustion chamber 12 can be used to achieve diffusion combustion and control the reaction rate; the setting of the pre-combustion chamber can limit the ignition environment to an environment with a lower equivalent ratio of combustible gas, which is easy to ignite; multiple flame fronts are formed through multiple small holes to quickly achieve diffusion combustion in the cylinder, and the ignition moment can be accurately controlled by the igniter;

[0048] Step 7: At the end of the compression stroke, the piston is located above the mixture injection valve, and the liquid ammonia fuel is injected into the cylinder body by the liquid ammonia injection valve 10 at high pressure according to a certain injection rule, and is mixed with the combustible mixture after the droplets are broken and vaporized to form a fuel mixture;

[0049] Step 8: The igniter 11 in the pre-combustion chamber 12 acts at a certain moment before the piston 13 reaches the highest position of the piston movement at the top dead center. The igniter 11 emits an electric spark to ignite the lean combustible gas with a relatively low equivalence ratio in the pre-combustion chamber 12. After ignition, the flame front enters the cylinder body through multiple small holes connected between the pre-combustion chamber 12 and the cylinder body. Each small hole corresponds to an ignition point. The multiple ignition points quickly ignite the combustible gas (fuel mixture) in the cylinder body. The gas in the cylinder body quickly burns and expands. After the piston 13 passes the top dead center, it is pushed by the expanding gas to do work.

[0050] Step nine: When the piston 13 moves downward until the combustion stops at a certain moment, the exhaust port 16 opens, and the exhaust gas in the cylinder body is discharged from the exhaust port 16 and flows to the heating exhaust gas inlet 5 of the plasma catalytic ammonia cracking reforming module; the piston 13 continues to move downward until the scavenging port 14 is opened to complete a two-stroke working cycle; when the piston 13 moves according to the sinusoidal function period under the action of the crankshaft crank, the sliding arc discharge exciter in the plasma generator 4 discharges according to the sinusoidal function periodic law, that is, when the piston 13 is above the hydrogen-ammonia mixture injection valve 9, the hydrogen-ammonia mixture injection valve 9 is in a closed state, and the electric exciter discharges, so as to make full use of time and ensure efficiency at the same time. When the quality is improved, similarly, the liquid ammonia fuel is sprayed into the cylinder body by the liquid ammonia high-pressure direct injection injection valve 10 according to the periodic law of the sine function. The hydrogen-ammonia mixture low-pressure injection valve, liquid ammonia high-pressure direct injection injection valve, exhaust port plunger, igniter, plasma generator, ammonia intake diverter valve, and hydrogen-rich gas mixing valve are all coordinated by the internal combustion engine integrated electronic control system and move with the working cycle of the internal combustion engine; under different working conditions of the internal combustion engine, the plasma generator works intelligently under the coordinated control of the internal combustion engine integrated electronic control system, and the precise control of the ammonia conversion rate / hydrogen-ammonia ratio is achieved through the precise control of the discharge energy and law, so that the performance and thermal efficiency of the power system are improved.

[0051] Specific implementation method eight: Combination Figure 1 To explain the present embodiment, the power system operation method based on cracking hydrogen production and high- and low-pressure combined injection of the present embodiment, in step 2, the high-temperature exhaust gas generated after combustion work enters the cracking heating tube 7 through the exhaust port 16 and the heating exhaust gas inlet 5, and exchanges heat with the ammonia in the catalyst shell, and after the heat exchange, is discharged to the external environment or the exhaust gas after-treatment device through the exhaust gas outlet 6, so that energy is fully utilized, energy saving and environmental protection.

[0052] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A power system based on hydrogen production by cracking and high and low pressure combined injection, characterized in that: It includes a plasma catalytic ammonia cracking reforming module and an internal combustion engine cylinder module, wherein the plasma catalytic ammonia cracking reforming module is connected to the internal combustion engine cylinder module, the plasma catalytic ammonia cracking reforming module is used to realize the catalysis of the fuel, and the internal combustion engine cylinder module is used to ignite the fuel to do work; The plasma catalytic ammonia cracking reforming module comprises an ammonia inlet (2), a hydrogen-ammonia reforming mixed gas outlet (3), a plasma generator (4), a cracking heating tube (7) and a catalyst shell, wherein the two ends of the catalyst shell are provided with an ammonia inlet (2) and a hydrogen-ammonia reforming mixed gas outlet (3), the plasma generator (4) is arranged in the catalyst shell, and the cracking heating tube (7) is arranged in the catalyst shell; The internal combustion engine cylinder module comprises a hydrogen-ammonia mixture injection valve (9), a liquid ammonia injection valve (10), an igniter (11), a pre-combustion chamber (12), a piston (13), a scavenging port (14), an exhaust port plunger (15), an exhaust port (16) and a cylinder body, wherein a piston (13) is slidably arranged in the cylinder body, a scavenging port (14) is arranged at the lower part of the side of the cylinder body, a hydrogen-ammonia mixture injection valve (9) is arranged in the middle part of the side of the cylinder body, a pre-combustion chamber (12), a liquid ammonia injection valve (10) and an exhaust port (16) are arranged on the top of the cylinder body, an igniter (11) is arranged in the pre-combustion chamber (12), and the exhaust port plunger (15) cooperates with the exhaust port (16).

2. The power system based on hydrogen production by cracking and high- and low-pressure combined injection according to claim 1 is characterized in that: The hydrogen-ammonia mixed gas low-pressure injection valve (9) adopts a low-pressure injection valve, and the liquid ammonia high-pressure direct injection injection valve (10) adopts a high-pressure direct injection injection valve.

3. The power system based on hydrogen production by cracking and high-low pressure combined injection according to claim 2 is characterized in that: The plasma catalytic ammonia cracking reforming module further comprises a heating waste gas inlet (5) and a waste gas outlet (6); both ends of the cracking heating tube (7) are provided with a heating waste gas inlet (5) and a waste gas outlet (6); and the exhaust port (16) is in communication with the heating waste gas inlet (5).

4. The power system based on hydrogen production by cracking and high-low pressure combined injection according to claim 3 is characterized in that: It also includes an ammonia gas intake diverter valve (1) and a hydrogen-rich gas mixing valve (8), wherein the ammonia source is connected to the ammonia gas intake port (2) and the inlet of the hydrogen-rich gas mixing valve (8) through the ammonia gas intake diverter valve (1), the hydrogen-ammonia reforming mixed gas outlet (3) is connected to the inlet of the hydrogen-rich gas mixing valve (8), and the outlet of the hydrogen-rich gas mixing valve (8) is connected to the hydrogen-ammonia mixed gas injection valve (9).

5. A power system operation method based on hydrogen production by cracking and high and low pressure combined injection, characterized in that: The power system based on hydrogen production by cracking and high- and low-pressure combined injection according to any one of claims 1 to 4 comprises the following steps: Step 1: Ammonia is split through the ammonia inlet splitter valve (1), with one part entering the catalyst housing through the reformer ammonia inlet (2) and the other part flowing to the hydrogen-rich gas mixing valve (8); Step 2: starting the heating tubes (7), and after ammonia flows into the catalyst shell, the plasma generator (4) discharges to generate plasma in the catalyst shell. Under the catalytic action of the plasma, part of the ammonia around the cracking heating tubes (7) is heated and catalytically cracked into hydrogen, thereby forming hydrogen-rich gas; Step 3: The hydrogen-rich gas flows to the hydrogen-rich gas mixing valve (8), and is mixed with another portion of ammonia gas to form a hydrogen-ammonia mixed gas, and the hydrogen-ammonia mixed gas flows to the ammonia-hydrogen mixed gas injection valve (9); Step 4: The piston (13) moves upward, and the scavenging is terminated when the lower end surface of the piston (13) is higher than the upper edge of the scavenging port (14); Step 5: The hydrogen-ammonia mixture is injected into the cylinder body through the hydrogen-ammonia mixture injection valve (9) in the early and middle stages of the compression stroke, and the disturbance caused by the upward movement of the piston (13) causes the gas in the cylinder to mix, thereby forming a combustible mixture; Step 6: During the upward movement of the piston (13), the combustible mixture in the cylinder body is gradually compressed and heated, and its reactivity is gradually increased, and the mixture enters and fills the pre-combustion chamber (12); Step 7: At the end of the compression stroke, liquid ammonia fuel is sprayed into the cylinder body through the liquid ammonia injection valve (10), and after droplets are broken and vaporized, it is mixed with the combustible mixed gas to form a fuel mixed gas; Step 8: The igniter (11) inside the pre-combustion chamber (12) acts before the piston (13) reaches the top dead center. The igniter (11) emits an electric spark to ignite the lean combustible gas with a relatively low equivalence ratio in the pre-combustion chamber (12). After ignition, the flame front enters the cylinder body. The ignition point quickly ignites the combustible gas in the cylinder body. The gas in the cylinder body quickly burns and expands. After the piston (13) passes the top dead center, it is pushed by the expanding gas to perform work. Step 9: When the combustion is terminated, the exhaust port plunger (15) leaves the exhaust port (16), and the exhaust gas in the cylinder body is discharged from the exhaust port (16).

6. The method for operating a power system based on hydrogen production by cracking and high- and low-pressure combined injection according to claim 5, characterized in that: In step 2, high-temperature exhaust gas generated after combustion enters the cracking heating tube (7) through the exhaust port (16) and the heating exhaust gas inlet (5), and exchanges heat with the ammonia in the catalyst shell. After the heat exchange, the high-temperature exhaust gas is discharged to the external environment or the exhaust gas post-treatment device through the exhaust gas outlet (6).

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