An engine system for mixed combustion of methanol and ammonia reforming gas

Abstract

The present application belongs to the internal combustion engine technical field, disclose a kind of engine system of methanol and ammonia reforming gas mixed combustion, including ammonia storage tank, ammonia heater, ammonia oil atomizer, ammonia reformer, tail gas heating pipe, ammonia reforming gas pump, ammonia reforming gas oil atomizer, ignition device, methanol oil atomizer, methanol storage tank, methanol high-pressure common rail, electronic control unit ECU and tail gas emptying pipe.The present application utilizes waste heat catalytic reforming ammonia, not only can recover the waste heat energy of exhaust gas, but also can prepare hydrogen, to efficiently utilize ammonia fuel;By directly spraying into the intake port of engine, the reforming gas containing ammonia, hydrogen and nitrogen forms the premixed gas of reforming gas / air;Methanol fuel is mixed with reforming gas by in-cylinder direct injection and burns.The injection amount of methanol and reforming gas is flexibly adjusted according to the load demand of engine, ammonia catalytic reforming rate, reforming amount and other conditions, to realize efficient and clean combustion of engine under various operating conditions.

Description

Technical Field

[0001] This invention belongs to the field of internal combustion engine technology and relates to an engine system that uses methanol and ammonia reformed gas for co-firing. Background Technology

[0002] Ammonia (NH3) has attracted widespread attention as a carbon-free fuel and a highly efficient hydrogen carrier. Currently, the storage and transportation of ammonia are relatively mature. However, using ammonia as an engine fuel faces two major challenges: slow combustion rate and excessively high nitrogen oxide emissions. Methanol, due to its high octane number and fast flame speed, is also gaining attention as a carbon-neutral fuel.

[0003] Ammonia reforming is an endothermic process, typically producing a mixture of 25% nitrogen and 75% hydrogen. Ammonia reforming rates exceeding 99% can be achieved at temperatures above 350°C. Online ammonia reforming can be realized using high-temperature exhaust gases. The hydrogen produced during ammonia reforming significantly increases the combustion rate of ammonia, and the laminar combustion rate of some of the reformed gas increases with the reforming rate. At a 40% reforming rate, the laminar combustion rate of the mixture is close to that of a methane / air mixture under the same conditions. Furthermore, ammonia reforming can significantly extend the lean-burn limit.

[0004] The combustion of ammonia fuel produces excessive amounts of fuel-type nitrogen oxides. Fermenting ammonia to produce hydrogen can avoid the direct combustion of ammonia fuel, thereby reducing the generation of fuel-type nitrogen oxides. However, during online reforming in engines, limitations in exhaust gas temperature and reforming volume make it difficult to directly meet the high-load demands of the engine.

[0005] When the high-load requirements of the engine cannot be directly met, mixing methanol with ammonia reformed gas for combustion can effectively solve the problem of efficient fuel combustion under all operating conditions. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide an engine system that co-fires methanol and ammonia reformed gas, using ammonia as a hydrogen carrier for ease of use and transportation, and utilizing the waste heat of engine exhaust gas to catalytically reform ammonia to supply hydrogen; furthermore, the injection quantities of methanol and ammonia reformed gas are adjusted according to the specific operating conditions of the engine to improve thermal efficiency and emission performance under various operating conditions, thus providing a low-carbon energy alternative for internal combustion engines.

[0007] The technical solution of the present invention:

[0008] An engine system for blending methanol and ammonia reformed gas includes a methanol storage tank, a methanol pump, a methanol control valve, a methanol high-pressure common rail, a methanol high-pressure common rail valve, a methanol direct injection intake pipe, a methanol injector, an engine, an ignition device, an engine exhaust pipe, an exhaust pipe, an ammonia storage tank, an ammonia pump, an ammonia control valve, a pressure sensor, an ammonia heater, an ammonia delivery pipe, an ammonia injector, a temperature sensor, an ammonia reformer, an ammonia reformed gas delivery pipe, an ammonia reformed gas pump, an ammonia reformed gas control valve, an ammonia reformed gas injector, an engine intake pipe, an exhaust pipe, and an electronic control unit (ECU).

[0009] The methanol storage tank sequentially pressurizes the methanol through a methanol pump, a methanol control valve, and a methanol high-pressure common rail, then injects the methanol into the engine cylinder through a direct methanol injection intake pipe. The ammonia storage tank sequentially converts liquid ammonia into gas through an ammonia pump, an ammonia control valve, and an ammonia heater, then injects it into the ammonia reformer through an ammonia delivery pipe. The outlet of the ammonia reformer is sequentially connected to a reforming gas pump and a reforming gas injection pipe, and the pressurized ammonia reformed gas is directly injected into the engine intake manifold. The engine exhaust manifold is sequentially connected to the exhaust gas inlet, exhaust gas outlet, heater inlet, and drive gas outlet of the ammonia reformer. The engine exhaust pipe recovers waste heat from the exhaust gas to the ammonia reformer.

[0010] The electronic control unit (ECU) is connected to the methanol control valve and pressure sensor, and adjusts the methanol inlet flow rate through feedback from the pressure sensor. In addition, the ECU is connected to the ammonia solution control valve, pressure sensor, and temperature sensor on the ammonia reformer, and adjusts the ammonia inlet flow rate by combining feedback from the pressure and temperature sensors. The ECU can also flexibly optimize the combustion process by controlling the fuel injection quantity of the two injectors according to the specific operating conditions of the engine.

[0011] The ammonia reformer uses the heat emitted by the engine to reform ammonia into hydrogen. The reformed ammonia gas is pressurized by the ammonia reforming pump and then injected into the engine through the ammonia reforming gas injector. The electronic control unit (ECU) determines the injection amount of methanol and reformed gas according to the specific operating conditions.

[0012] The injection quantities of methanol and reformed gas are adjusted according to engine load requirements, ammonia catalytic reforming rate, and reforming quantity to achieve efficient and clean combustion of the engine under various operating conditions.

[0013] When the ammonia reforming rate is high, the ratio of reformed gas to methanol is adjusted according to the operating conditions; when the ammonia reforming rate is low, methanol is used as the main fuel, with a small amount of reformed gas used, in order to avoid the high NOx emissions caused by directly burning ammonia in the reformed gas.

[0014] The beneficial effects of this invention are:

[0015] 1. This invention effectively combines the co-firing technology of methanol and ammonia reformed gas, and improves combustion efficiency by utilizing the waste heat of the exhaust gas.

[0016] 2. Ammonia, as a carrier of hydrogen, is safer and more convenient than directly transporting hydrogen, and can be used to generate hydrogen online according to the engine's hydrogen requirements.

[0017] 3. The hydrogen produced after reforming ammonia burns quickly, which helps to extend the lean-burn limit and reduce NOx emissions from fuels.

[0018] 4. The system flexibly adjusts the injection volume of methanol and reformate gas through optimized control strategies to adapt to different operating conditions. Its low emission characteristics during combustion help reduce environmental pollution. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall system structure of the present invention;

[0020] In the diagram: 1-Methanol storage tank; 2-Methanol pump; 3-Methanol control valve; 4-Methanol high-pressure common rail; 5-Methanol high-pressure common rail valve; 6-Methanol direct injection intake pipe; 7-Methanol injector; 8-Engine; 9-Ignition device; 10-Engine exhaust pipe; 11-Exhaust pipe; 12-Ammonia storage tank; 13-Ammonia pump; 14-Ammonia control valve; 15-Pressure sensor; 16-Ammonia heater; 17-Ammonia delivery pipe; 18-Ammonia injector; 19-Temperature sensor; 20-Ammonia reformer; 21-Ammonia reformed gas delivery pipe; 22-Ammonia reformed gas pump; 23-Ammonia reformed gas control valve; 24-Ammonia reformed gas injector; 25-Engine intake pipe; 26-Exhaust vent pipe; 27-Electronic control unit (ECU). Detailed Implementation

[0021] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0022] Combination Figure 1 The relative positions, connections, and working principles of the components in the methanol and ammonia reformed gas co-firing engine system are explained below:

[0023] like Figure 1 The diagram illustrates the specific structure of an embodiment of the engine system proposed in this invention, which utilizes waste heat from engine exhaust to reform ammonia online for hydrogen production and co-firing methanol and ammonia reformed gas.

[0024] The system includes: a methanol storage tank 1, a methanol pump 2, a methanol control valve 3, a methanol high-pressure common rail 4, a methanol high-pressure common rail valve 5, a methanol direct injection intake pipe 6, a methanol injector 7, an engine 8, an ignition device 9, an engine exhaust pipe 10, an exhaust pipe 11, an ammonia storage tank 12, an ammonia pump 13, an ammonia control valve 14, a pressure sensor 15, an ammonia heater 16, an ammonia delivery pipe 17, an ammonia injector 18, a temperature sensor 19, an ammonia reformer 20, an ammonia reformed gas delivery pipe 21, an ammonia reformed gas pump 22, an ammonia reformed gas control valve 23, an ammonia reformed gas injector 24, an engine intake pipe 25, an exhaust vent pipe 26, and an electronic control unit (ECU) 27.

[0025] A methanol injector 7 is installed above the engine 8; the methanol injector 7 is connected to the methanol high-pressure common rail 4 via a methanol direct injection intake pipe 6; the other end of the methanol high-pressure common rail 4 is connected to the methanol storage tank 1 via a methanol delivery pipe; a methanol pump 2 and a methanol control valve 3 are installed on the methanol delivery pipe; a methanol high-pressure common rail valve 5 is installed on the methanol high-pressure common rail 4; an engine intake pipe 25 is also installed above the engine 8; an ammonia reforming gas delivery pipe 21 is connected to the engine intake pipe 25 via an ammonia reforming gas pump 22, an ammonia reforming gas control valve 23, and an ammonia reforming gas injector 24; the ammonia reformer 20 catalytically reforms ammonia into a hydrogen-rich mixed gas using waste heat from engine exhaust gas; the ammonia reformer 20 is connected to the engine exhaust inlet and the ammonia reforming gas outlet respectively. The ammonia inlet and engine exhaust outlet are connected; the engine exhaust pipe 10 is connected to the engine exhaust inlet; the ammonia reforming gas outlet is connected to the ammonia reforming gas delivery pipe 21; the ammonia heater 16 is connected to the ammonia inlet of the ammonia reformer 20 through the ammonia injector 18, and is connected to the engine exhaust outlet through the exhaust pipe 11; the ammonia heater 16 has four passages: exhaust pipe 11, ammonia outlet, ammonia solution inlet, and exhaust vent pipe 26; the ammonia storage tank 12 is connected to the ammonia solution inlet of the ammonia heater 16 in sequence through the ammonia pump 13, ammonia control valve 14, and pressure sensor 15; the ammonia reformer 20 is equipped with a temperature sensor 19; the exhaust vent pipe 26 is connected to the engine exhaust pipe 10 through the exhaust pipe 11.

[0026] The methanol control valve 3, methanol high-pressure common rail valve 5, ammonia reforming gas control valve 23, ammonia control valve 14, pressure sensor 15, ammonia reforming gas injector 24, methanol injector 7, ignition device 9, ammonia injector 18 and temperature sensor 19 are respectively connected to the electronic control unit ECU 27.

[0027] The ammonia reformer 20 uses the heat emitted by the engine to reform ammonia to produce hydrogen. The reformed ammonia gas is pressurized by the ammonia reformer pump 22 and then delivered to the engine through the ammonia reformer injector 24. The electronic control unit ECU 27 controls the methanol injector 7 and the ammonia injector 18 to adjust the methanol and ammonia gas according to the specific operating conditions. The electronic control unit ECU 27 also feeds back the ammonia pump 13, ammonia control valve 14 and pressure sensor 15 according to the demand for reformed gas to adjust the ammonia flow rate from the ammonia storage tank 12 to the ammonia heater 16.

[0028] The control principle of this invention is as follows:

[0029] When the engine is running, the exhaust gas from the engine flows through the engine exhaust pipe 10 to the ammonia reformer 20, and then to the ammonia heater 16. During this process, some heat is transferred to the ammonia reformer 20 and the ammonia heater 16 respectively, and finally discharged into the atmosphere through the exhaust pipe 26.

[0030] The electronic control unit (ECU) 27 receives a signal from the temperature sensor 19. When the temperature of the ammonia reformer 20 reaches the temperature required for the ammonia reforming reaction, it turns on the power to the ammonia pump 13 and the ammonia control valve 14, and delivers the ammonia solution in the ammonia storage tank 12 to the ammonia heater 16. The pressure sensor 15 is used to detect the ammonia solution delivery flow rate. The ECU 27 turns on the ammonia injector 18 and delivers the ammonia solution to the ammonia reformer 20 according to the initial preset delivery flow rate. The ammonia reformer 20 catalytically reforms the ammonia into hydrogen-rich reformed gas, and delivers it to the ammonia reformed gas delivery pipe 21 through the reformed gas outlet pipe connected to the ammonia reformer 20. The ammonia reformed gas delivery pipe 21 is equipped with an ammonia reformed gas pump 22 and an ammonia reformed gas control valve 23 to pressurize and control the ammonia reformed gas, and finally injects it into the engine intake manifold 25 through the ammonia reformed gas injector 24.

[0031] The electronic control unit (ECU) 27 activates the methanol injector 7 and the ammonia reformer injector 24 based on signals from the methanol high-pressure common rail valve 5, in order to precisely control the supply of methanol and ammonia reformer gas according to different engine operating conditions. As the ammonia reformer gas enters the engine combustion chamber through the engine intake manifold 25, it mixes with methanol gas to serve as engine fuel. The ECU 27 controls the ammonia control valve 14 based on feedback of reformer gas demand and signals from the pressure sensor 15, thereby adjusting the ammonia flow rate delivered by the ammonia pump 13 to the ammonia heater 16. Simultaneously, the ECU 27 also adjusts the ammonia injector 18 based on the reformer gas demand to control the ammonia flow rate from the ammonia heater 16 to the ammonia reformer 20.

Claims

1. An engine system for co-firing methanol and ammonia reformed gas, characterized in that, The methanol and ammonia reformed gas co-firing engine system includes a methanol storage tank (1), a methanol pump (2), a methanol control valve (3), a methanol high-pressure common rail (4), a methanol high-pressure common rail valve (5), a methanol direct injection intake pipe (6), a methanol injector (7), an engine (8), an ignition device (9), an engine exhaust pipe (10), an exhaust pipe (11), an ammonia storage tank (12), an ammonia pump (13), an ammonia control valve (14), a pressure sensor (15), an ammonia heater (16), an ammonia delivery pipe (17), an ammonia injector (18), a temperature sensor (19), an ammonia reformer (20), an ammonia reformed gas delivery pipe (21), an ammonia reformed gas pump (22), an ammonia reformed gas control valve (23), an ammonia reformed gas injector (24), an engine intake pipe (25), an exhaust pipe (26), and an electronic control unit (ECU) (27). A methanol injector (7) is installed above the engine (8); the methanol injector (7) is connected to the methanol high-pressure common rail (4) through the methanol direct injection intake pipe (6); the other end of the methanol high-pressure common rail (4) is connected to the methanol storage tank (1) through the methanol delivery pipe; the methanol delivery pipe is equipped with a methanol pump (2) and a methanol control valve (3); a methanol high-pressure common rail valve (5) is installed on the methanol high-pressure common rail (4); an engine intake pipe (25) is also installed above the engine (8); the ammonia reforming gas delivery pipe (21) is connected to the engine intake pipe (25) in sequence through the ammonia reforming gas pump (22), the ammonia reforming gas control valve (23), and the ammonia reforming gas injector (24); the ammonia reformer (20) is connected to the engine exhaust inlet, the ammonia reforming gas outlet, the ammonia inlet, and the engine exhaust outlet respectively; The engine exhaust pipe (10) is connected to the engine exhaust inlet; the ammonia reforming gas outlet is connected to the ammonia reforming gas delivery pipe (21); the ammonia heater (16) is connected to the ammonia inlet of the ammonia reformer (20) through the ammonia delivery pipe (17) and the ammonia injector (18); the ammonia heater (16) is connected to the engine exhaust outlet through the exhaust pipe (11); the ammonia heater (16) has four passages: exhaust pipe (11), ammonia outlet, ammonia solution inlet and exhaust gas vent pipe (26); the ammonia storage tank (12) is connected to the ammonia solution inlet of the ammonia heater (16) in sequence through the ammonia pump (13), the ammonia control valve (14) and the pressure sensor (15); the ammonia reformer (20) is equipped with a temperature sensor (19); the exhaust gas vent pipe 26 is connected to the engine exhaust pipe (10) through the exhaust pipe (11); The methanol control valve (3), methanol high-pressure common rail valve (5), ammonia reforming gas control valve (23), ammonia control valve (14), pressure sensor (15), ammonia reforming gas injector (24), methanol injector (7), ignition device (9), ammonia injector (18) and temperature sensor (19) are respectively connected to the electronic control unit (ECU) (27).

2. The engine system for co-firing methanol and ammonia reformed gas according to claim 1, characterized in that, The ammonia reformer (20) uses the heat emitted by the engine to reform ammonia to produce hydrogen. The reformed ammonia gas is pressurized by the ammonia reformer pump (22) and then injected into the engine (8) through the ammonia reformer injector (24). The electronic control unit (ECU) (27) determines the injection amount of methanol and reformed gas according to the specific operating conditions.

3. The engine system for co-firing methanol and ammonia reformed gas according to claim 1, characterized in that, The injection quantities of methanol and reformed gas are adjusted according to engine load requirements, ammonia catalytic reforming rate, and reforming quantity to achieve efficient and clean combustion of the engine under various operating conditions.

4. The engine system for co-firing methanol and ammonia reformed gas according to claim 1, characterized in that, When the ammonia reforming rate is high, the ratio of reformed gas to methanol is adjusted according to the operating conditions; when the ammonia reforming rate is low, methanol is used as the main fuel, with a small amount of reformed gas used, in order to avoid the high NOx emissions caused by directly burning ammonia in the reformed gas.

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