Internal mixing type ammonia-hydrogen dual-fuel low-pressure coaxial ejector and control method

Abstract

The invention discloses an internal mixing type ammonia-hydrogen dual-fuel low-pressure coaxial ejector and a control method. The internal mixing type ammonia-hydrogen dual-fuel low-pressure coaxial ejector comprises a coaxial injection system and an ammonia online cracking hydrogen production system. The ammonia cracking hydrogen production system comprises a liquid ammonia branch and a hydrogen branch; when fuel oil is started, the two gate valves are opened at the same time, liquid ammonia is released at the two outlets of the liquid ammonia storage tank 1 at the same time, and after the pressure of the liquid ammonia of the liquid ammonia branch reaches 0.8 Mpa-10 Mpa through the pressure pump, the liquid ammonia enters a fuel cavity of the dual-fuel coaxial injection system. Liquid ammonia of a liquid ammonia release branch passes through a vaporizer, a heat exchanger, a decomposing furnace and a separator at a first outlet of the ammonia storage tank 1 by opening a first gate valve 2 to obtain high-purity hydrogen, and the high-purity hydrogen passes through a compressor to reach the pressure close to the same as that of the liquid ammonia in the liquid ammonia branch and then enters a mixing cavity; at the moment, the ECU controls the pressure adjusting screw to move upwards to drive the needle valve to move upwards, so that liquid ammonia fuel enters the mixing cavity, and liquid ammonia and hydrogen are mixed and injected in the mixing cavity. The method can be carried out in a low-pressure (0.8 Mpa-10 Mpa) state, and the problem that the atomization effect is poor is solved.

Description

Technical Field

[0001] The present invention belongs to the field of power and energy engineering, and in particular relates to an internal mixing type ammonia-hydrogen dual-fuel low-pressure coaxial injector and a control method thereof. Background Art

[0002] The fuel injector is a key component in the fuel supply system of an internal combustion engine. It is responsible for spraying fuel into the combustion chamber of the internal combustion engine at a specific pressure, atomization state and time.

[0003] In the field of marine engines, most engines use dual fuel for injection, while traditional injectors are mostly single fuel injectors, which cannot inject different types of fuel in the cylinder to form active stratification to reduce the combustion rate and increase the load of the engine. Therefore, when the traditional injector is matched with the dual fuel strategy, it is necessary to use multiple injectors, which will inevitably complicate the injection device inside the engine, and the dual fuel injection device can overcome the above defects. The current dual fuel injector structure is generally coaxial injection and multi-axial injection, and the multi-axial injection device has a complex structure and is relatively less studied. There are many studies on dual fuel coaxial injection devices, which are generally divided into internal mixing and external mixing. The internal mixing type generally achieves fuel mixing inside the injector and then injects it into the cylinder, while the external mixing type is that the injector first injects two fuels into the cylinder and mixes them inside the cylinder. The traditional fuel injection method of the injector is mainly cross flow injection. The so-called cross flow injection is an atomization method that injects liquid fuel into the gas cross flow in a columnar form. The main purpose of designing an internal mixing dual fluid injector is to convert the liquid column into a liquid film by atomizing air. When encountering cross flow, the liquid film should promote injection / spray atomization. The dual-fuel coaxial injector has a simple structure and is easy to implement. It is helpful to reduce carbon emissions in the shipping industry when combined with clean fuels such as ammonia. However, due to its low calorific value, ammonia requires about three times as much fuel as traditional fuels to achieve the same cruising range for vehicles and ships compared to traditional fuels such as diesel. Secondly, ammonia has a high ignition temperature, is difficult to ignite, and has a slow combustion rate, so other activated fuels are required for ignition. Hydrogen has the characteristics of high energy density and fast combustion rate. Blending hydrogen with ammonia can complement ammonia-hydrogen fuels to achieve clean and efficient combustion. In addition, hydrogen has high technical barriers to storage and transportation costs, while ammonia is an ideal hydrogen storage fuel that is relatively easy to store and transport. Therefore, an online ammonia reforming hydrogen production process can be used to achieve ammonia-hydrogen dual-fuel coaxial injection. Summary of the invention

[0004] The object of the present invention is to provide an internal mixing ammonia-hydrogen dual fuel low-pressure coaxial injector and a control method.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] An internal mixing ammonia-hydrogen dual-fuel low-pressure coaxial injector, comprising a coaxial injection system and an ammonia cracking hydrogen production system; the coaxial injection system is provided with an injector on a cylinder head; the ammonia cracking hydrogen production system comprises a liquid ammonia branch and a hydrogen branch; the liquid ammonia branch comprises a No. 2 port of an ammonia storage tank connected by a pipeline, a No. 2 gate valve, a pressure pump and a liquid ammonia inlet of the dual-fuel coaxial injection system; the hydrogen branch comprises a No. 1 port of an ammonia storage tank connected in sequence by a pipeline, a No. 1 gate valve, a vaporizer, a heat exchanger, a decomposition furnace, a separator, a compressor, a flow A flow controller and a hydrogen inlet of the dual-fuel coaxial injection system; the liquid ammonia released from the No. 2 outlet of the ammonia storage tank by opening the No. 2 gate valve enters the dual-fuel coaxial injection system through the liquid ammonia branch after being pressurized by the booster pump; the liquid ammonia is released from the No. 1 outlet of the ammonia storage tank by opening the No. 1 gate valve, and the liquid ammonia passes through the vaporizer, heat exchanger, decomposition furnace, and separator to obtain high-purity hydrogen. The separated hydrogen is pressurized by a compressor to be consistent with the pressure of the liquid ammonia in the liquid ammonia branch, and then enters the coaxial injection system through the flow controller.

[0007] Furthermore, the dual-fuel coaxial injection system includes a shell, and the interior of the shell includes a pressure regulating screw, a spring seat, a pressure regulating spring, a needle valve, and a spray hole from top to bottom; the pressure regulating screw is connected to the ECU control system; the lower part of the spring seat is fixedly connected to the pressure regulating spring, and the other end of the pressure regulating spring is connected to the top of the needle valve; a gasket is arranged between the shell and the top of the needle valve.

[0008] Furthermore, a liquid ammonia inlet channel and a hydrogen inlet channel are provided on the left side of the shell; a check valve is provided on the liquid ammonia inlet channel to prevent ammonia fuel from flowing back; and a one-way valve is provided on the hydrogen inlet channel to prevent gas from flowing back.

[0009] Furthermore, a valve sleeve is provided on the outer wall of the needle valve with a gap therebetween; a fuel chamber is provided between the valve sleeve and the shell for storing liquid ammonia fuel; a mixing chamber is provided at the lower part of the fuel chamber for mixing ammonia fuel with hydrogen; a single or multiple spray holes are provided at the lower part of the mixing chamber.

[0010] Furthermore, the liquid ammonia passes through a pressure pump and then enters the fuel chamber of the dual-fuel coaxial injection system through a liquid ammonia branch; the hydrogen passes through a hydrogen branch and then enters the mixing chamber of the dual-fuel coaxial injection system.

[0011] Furthermore, the outer wall surface of the lower end of the needle valve is tightly fitted with the inner wall surface of the shell. When the needle valve is lifted, the fuel in the fuel chamber flows into the mixing chamber through the gap between the wall surfaces; the liquid ammonia and hydrogen are mixed in the mixing chamber; and then the injection is completed through the nozzle hole set on the mixing chamber.

[0012] Furthermore, the pressure of the liquid ammonia applied by the pressure pump is: 0.8Mpa-10Mpa.

[0013] A control method for an internally mixed ammonia-hydrogen dual-fuel low-pressure coaxial injector is provided, wherein the internally mixed ammonia-hydrogen dual-fuel low-pressure coaxial injector comprises three injection modes: an ammonia-hydrogen dual-fuel mixed injection mode, a single ammonia fuel injection mode and a single hydrogen fuel injection mode:

[0014] Ammonia-hydrogen dual-fuel mixed injection mode: when the fuel is started, the No. 1 gate valve and the No. 2 gate valve are opened at the same time, and the liquid ammonia is released from the No. 2 outlet of the liquid ammonia storage tank. After the liquid ammonia reaches a pressure of 0.8Mpa-10Mpa through the booster pump, it enters the fuel chamber of the dual-fuel coaxial injection system through the liquid ammonia branch; the No. 1 outlet of the ammonia storage tank releases liquid ammonia by opening the No. 1 gate valve, and the liquid ammonia passes through the vaporizer, heat exchanger, decomposition furnace, and separator to obtain high-purity hydrogen. The obtained high-purity hydrogen passes through the compressor to reach the same pressure as the liquid ammonia in the liquid ammonia branch; at this time, the ECU control system controls the pressure regulating screw and the spring seat to move upward, driving the needle valve to move upward so that the liquid ammonia fuel in the fuel chamber enters the mixing chamber, and at the same time, the hydrogen compressed by the hydrogen branch enters the mixing chamber to achieve mixing of liquid ammonia and hydrogen, and then is injected into the cylinder through the spray hole set on the mixing chamber;

[0015] Single ammonia fuel injection mode: open the No. 2 gate valve and close the No. 1 gate valve, and the liquid ammonia is released from the No. 2 outlet of the liquid ammonia storage tank. After the released liquid ammonia reaches the required pressure through the booster pump, it enters the fuel chamber of the dual-fuel coaxial injection system through the liquid ammonia branch; the ECU control system controls the pressure regulating screw and the spring seat to move upward, driving the needle valve to move upward so that the liquid ammonia fuel in the fuel chamber enters the mixing chamber and is sprayed into the cylinder through the spray hole set on the mixing chamber;

[0016] Single hydrogen fuel injection mode: open gate valve No. 1 and close gate valve No. 2. Liquid ammonia passes through the vaporizer, heat exchanger, decomposition furnace, and separator to obtain high-purity hydrogen. The obtained high-purity hydrogen is pressurized to the required pressure by the compressor, enters the mixing chamber through the flow controller, and is sprayed into the cylinder through the spray hole set on the mixing chamber.

[0017] The beneficial effects of the present invention are:

[0018] The dual-fuel coaxial injector described in the present invention provides liquid ammonia and hydrogen from a single ammonia fuel to achieve ammonia-hydrogen mixed injection and injection of a single ammonia fuel and hydrogen fuel. At the same time, the internal mixing dual-fuel coaxial injector described in the present invention can be operated under low pressure (0.8Mpa-10Mpa). This is because during dual fluid injection, the liquid column injected into the mixing chamber moves violently in the mixing port, forming a liquid film flow at the outlet of the mixing port; after injection, the turbulent liquid film also breaks violently and transforms into a well-atomized jet. It can make up for the problem of poor atomization effect under low pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic structural diagram of the dual-fuel coaxial injection system described in the present invention.

[0020] Figure 2 Schematic diagram of the mixing chamber of the present invention.

[0021] Figure 3 Schematic diagram of the spray hole of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings.

[0023] like Figure 1 As shown, a dual-fuel coaxial injector includes an ammonia cracking hydrogen production system and a dual-fuel coaxial injection system. The ammonia cracking hydrogen production system includes a hydrogen branch 7 and a liquid ammonia branch 23; the hydrogen branch 7 is connected to the ammonia storage tank 1, the first gate valve 2, the vaporizer 3, the heat exchanger 4, the decomposition furnace 5, the separator 6, the compressor 8, the flow controller 9, and the one-way valve 10 in sequence through a pipeline; the liquid ammonia branch is connected to the liquid ammonia storage tank 1, the second gate valve 24, the booster pump 22, and the check valve 21 in sequence through a pipeline; the coaxial injection system is arranged in the injector on the cylinder head.

[0024] The dual-fuel coaxial injection system is used to inject liquid ammonia fuel and hydrogen fuel, and can realize both mixed injection of liquid ammonia and hydrogen and separate injection of liquid ammonia and hydrogen.

[0025] The ammonia storage tank 1 has two outlets, outlet No. 1 is connected to gate valve No. 1 2 for controlling the on-off of hydrogen branch 7, and outlet No. 2 is connected to gate valve No. 2 24 for controlling the on-off of liquid ammonia branch 23. The liquid ammonia released from outlet No. 2 of the ammonia storage tank 1 reaches the corresponding pressure (0.8Mpa-10Mpa) through the pressure pump 22, and then enters the fuel chamber 13 of the dual-fuel coaxial injection system through the liquid ammonia branch 23. The outlet No. 1 of the ammonia storage tank 1 releases liquid ammonia by opening gate valve No. 1 2, and the liquid ammonia passes through the vaporizer 3, the heat exchanger 4, the decomposition furnace 5, and the separator 6 to obtain high-purity hydrogen. The separated hydrogen is pressurized by the compressor 8 to a pressure close to that of the liquid ammonia in the liquid ammonia branch, and then enters the mixing chamber 12 in the coaxial injection system through the flow controller 9; the liquid ammonia branch 23 is provided with a check valve 21 to prevent the reflux of liquid ammonia; the hydrogen branch 7 is provided with a one-way valve 10 to prevent the reflux of gas.

[0026] The dual-fuel coaxial injection system includes a shell 17, which includes a pressure regulating screw 18, a spring seat 19, a pressure regulating spring 16, a needle valve 15, a fuel chamber 13, a mixing chamber 12, and a spray hole 11 from top to bottom; the outer wall of the needle valve 15 is covered with a valve sleeve 14; a gasket 20 is arranged between the shell 17 and the top of the needle valve 15 to reduce the impact and wear between the needle valve and the shell when it moves back and forth.

[0027] The pressure regulating screw 18 is connected to the ECU control system. When the fuel is started, the spring seat 19 connected to the pressure regulating screw 18 controlled by the ECU includes the pressure regulating spring 16 at the lower end of the spring seat 19, which simultaneously moves upward to drive the needle valve 15 connected to the pressure regulating spring 16 to move upward. When the needle valve 15 is lifted, the liquid ammonia fuel enters the gap between the needle valve 15 and the valve sleeve 14. When the needle valve 15 is lifted, the outer wall surface of the needle valve is separated from the inner wall surface of the shell. The liquid ammonia enters the mixing chamber 12 through the gap after the outer wall surface of the needle valve 15 is separated from the inner wall surface of the shell, and the injection is completed through the spray hole 11 arranged on the mixing chamber 12. The present invention takes four spray holes as an example. Figure 3 shown.

[0028] Ammonia-hydrogen dual fuel mixed injection mode: When the fuel is started, the No. 1 gate valve 2 and the No. 2 gate valve 24 are opened at the same time, and the corresponding liquid ammonia is released from the No. 2 outlet of the liquid ammonia storage tank 1. After the released liquid ammonia reaches the corresponding pressure (0.8Mpa-10Mpa) through the booster pump 22, it enters the fuel chamber 13 of the dual fuel coaxial injection system through the liquid ammonia branch 23. The No. 1 outlet of the ammonia storage tank 1 releases liquid ammonia by opening the No. 1 gate valve 2. The liquid ammonia passes through the vaporizer 3, the heat exchanger 4, the decomposition furnace 5, and the separator 6 to obtain high-purity hydrogen. The obtained high-purity hydrogen passes through the compressor 8 to reach a pressure close to that of the liquid ammonia in the liquid ammonia branch 7. The hydrogen enters the mixing chamber 12 of the dual fuel coaxial injection system. At this time, the ECU controls the pressure regulating screw 18 to move upward to drive the needle valve 15 to move upward so that the liquid ammonia fuel enters the mixing chamber 12. At the same time, the compressed hydrogen enters the mixing chamber 12 to achieve the mixing of liquid ammonia and hydrogen, and then is injected into the cylinder through the spray hole 11 set on the mixing chamber 12.

[0029] Single ammonia fuel injection mode: Open the No. 2 gate valve 24 and close the No. 1 gate valve 2, and the corresponding liquid ammonia is released from the No. 2 outlet of the liquid ammonia storage tank 1. After the released liquid ammonia reaches the corresponding pressure requirement through the booster pump 22, it enters the fuel chamber 13 of the dual-fuel coaxial injection system through the liquid ammonia branch 23. The ECU drives the needle valve 15 to move upward by controlling the pressure regulating screw 18, and the liquid ammonia in the fuel chamber 13 enters the mixing chamber 12 and is sprayed into the cylinder through the spray hole 11 set on the mixing chamber 12.

[0030] Single hydrogen fuel injection mode: open gate valve No. 1 2 and close gate valve No. 2 24. Liquid ammonia passes through vaporizer 3, heat exchanger 4, decomposition furnace 5, and separator 6 to obtain high-purity hydrogen. The separated hydrogen is pressurized to the required pressure by compressor 8, enters the mixing chamber 12 in the dual-fuel coaxial injection system through flow controller 9, and then is injected into the cylinder through the spray hole 11 set on the mixing chamber 12.

[0031] 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. An internal mixing ammonia-hydrogen dual fuel low pressure coaxial injector, characterized in that: The invention comprises a coaxial injection system and an ammonia cracking hydrogen production system; the coaxial injection system comprises an injector arranged on a cylinder head; the ammonia cracking hydrogen production system comprises a liquid ammonia branch (23) and a hydrogen branch (7); the liquid ammonia branch (23) comprises a No. 2 port of an ammonia storage tank (1), a No. 2 gate valve (24), a pressure pump (22) and a liquid ammonia inlet of the dual-fuel coaxial injection system connected by a pipeline; the hydrogen branch (7) comprises a No. 1 port of an ammonia storage tank (1), a No. 1 gate valve (2), a vaporizer (3), a heat exchanger (4), a decomposition furnace (5), a separator (6), a compressor (8), a flow controller (9) and A hydrogen inlet for the dual-fuel coaxial injection system; liquid ammonia released from the No. 2 outlet of the ammonia storage tank (1) by opening the No. 2 gate valve (24) enters the dual-fuel coaxial injection system through a liquid ammonia branch (23) after being pressurized by a pressure pump (22); liquid ammonia is released from the No. 1 outlet of the ammonia storage tank (1) by opening the No. 1 gate valve (2), and the liquid ammonia passes through a vaporizer (3), a heat exchanger (4), a decomposition furnace (5), and a separator (6) to obtain high-purity hydrogen; the separated hydrogen is pressurized by a compressor (8) to the same pressure as the liquid ammonia in the liquid ammonia branch (23), and then enters the coaxial injection system through a flow controller (9).

2. The internal mixing ammonia-hydrogen dual fuel low pressure coaxial injector according to claim 1, characterized in that: The dual-fuel coaxial injection system comprises a housing (17), wherein the housing (17) comprises a pressure regulating screw (18), a spring seat (19), a pressure regulating spring (16), a needle valve (15), and a spray hole (11) in order from top to bottom; the pressure regulating screw (18) is connected to an ECU control system; the lower part of the spring seat (19) is fixedly connected to the pressure regulating spring (16), and the other end of the pressure regulating spring (16) is connected to the top end of the needle valve (15); and a gasket (20) is arranged between the housing (17) and the top end of the needle valve (15).

3. The internal mixing ammonia-hydrogen dual fuel low pressure coaxial injector according to claim 2, characterized in that: The left side of the shell (17) is provided with a liquid ammonia inlet channel and a hydrogen inlet channel; the liquid ammonia inlet channel is provided with a check valve (21) to prevent ammonia fuel from flowing back; the hydrogen inlet channel is provided with a check valve (10) to prevent gas from flowing back.

4. The internal mixing ammonia-hydrogen dual fuel low pressure coaxial injector according to claim 2, characterized in that: The outer wall of the needle valve (15) is provided with a valve sleeve (14) with a gap therebetween; a fuel chamber (13) is provided between the valve sleeve (14) and the housing (17) for storing liquid ammonia fuel; a mixing chamber (12) is provided at the bottom of the fuel chamber (13) for mixing ammonia fuel with hydrogen; and a single or multiple spray holes (11) are provided at the bottom of the mixing chamber (13).

5. The internal mixing ammonia-hydrogen dual fuel low pressure coaxial injector according to claim 4, characterized in that: The liquid ammonia passes through a pressure pump (22) and enters the fuel chamber (13) of the dual-fuel coaxial injection system through a liquid ammonia branch (23); the hydrogen passes through a hydrogen branch (7) and enters the mixing chamber (12) of the dual-fuel coaxial injection system.

6. The internal mixing ammonia-hydrogen dual fuel low pressure coaxial injector according to claim 5, characterized in that: The outer wall surface of the lower end of the needle valve (15) is tightly fitted with the inner wall surface of the shell (17). When the needle valve (15) is lifted, the fuel in the fuel chamber (13) flows into the mixing chamber (13) through the gap between the wall surfaces; the liquid ammonia and the hydrogen are mixed in the mixing chamber (13); and then the injection is completed through the injection hole (11) arranged on the mixing chamber (12).

7. The internal mixing ammonia-hydrogen dual fuel low pressure coaxial injector according to claim 1, characterized in that: The pressure of the liquid ammonia applied by the pressure pump (22) is 0.8Mpa-10Mpa.

8. A control method for an internal mixing ammonia-hydrogen dual fuel low pressure coaxial injector, characterized in that: An internally mixed ammonia-hydrogen dual-fuel low-pressure coaxial injector according to any one of claims 1 to 7 is used, including an ammonia-hydrogen dual-fuel mixed injection mode, a single ammonia fuel injection mode and a single hydrogen fuel injection mode, three injection modes: Ammonia-hydrogen dual fuel mixed injection mode: when the fuel is started, the No. 1 gate valve (2) and the No. 2 gate valve (24) are opened at the same time, and the No. 2 outlet of the liquid ammonia storage tank (1) releases liquid ammonia. After the liquid ammonia reaches a pressure of 0.8Mpa-10Mpa through the pressure pump (22), it enters the fuel chamber (13) of the dual fuel coaxial injection system through the liquid ammonia branch (23); the No. 1 outlet of the ammonia storage tank (1) releases liquid ammonia by opening the No. 1 gate valve (2), and the liquid ammonia passes through the vaporizer (3), the heat exchanger (4), the decomposition furnace (5), the separator ( 6) and then high-purity hydrogen is obtained. The obtained high-purity hydrogen passes through the compressor (8) to reach a pressure consistent with the liquid ammonia in the liquid ammonia branch (23); at this time, the ECU control system controls the pressure regulating screw (18) and the spring seat (19) to move upward, driving the needle valve (15) to move upward so that the liquid ammonia fuel in the fuel chamber (13) enters the mixing chamber (12), and at the same time, the hydrogen compressed by the hydrogen branch (7) enters the mixing chamber (12) to achieve mixing of liquid ammonia and hydrogen, and then is sprayed into the cylinder through the spray hole (11) provided on the mixing chamber (12); Single ammonia fuel injection mode: open the No. 2 gate valve (24) and close the No. 1 gate valve (2), and the No. 2 outlet of the liquid ammonia storage tank (1) releases liquid ammonia. After the released liquid ammonia reaches the required pressure through the booster pump (22), it enters the fuel chamber (13) of the dual-fuel coaxial injection system through the liquid ammonia branch (23); the ECU control system controls the pressure regulating screw (18) and the spring seat (19) to move upward, driving the needle valve (15) to move upward so that the liquid ammonia fuel in the fuel chamber (13) enters the mixing chamber (12), and is sprayed into the cylinder through the spray hole (11) provided on the mixing chamber (12); Single hydrogen fuel injection mode: open the No. 1 gate valve (2) and close the No. 2 gate valve (24), and the liquid ammonia passes through the vaporizer (3), the heat exchanger (4), the decomposition furnace (5), and the separator (6) to obtain high-purity hydrogen. The obtained high-purity hydrogen is pressurized to a required pressure by the compressor (8), enters the mixing chamber (12) through the flow controller (9), and is injected into the cylinder through the spray hole (11) provided on the mixing chamber (12).

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