Methanol / synthesis gas engine suitable for inland ship methanol online reforming hydrogen production and operation control method of methanol / synthesis gas engine

Abstract

The invention discloses an inland ship methanol online reforming hydrogen production methanol / synthesis gas engine and an operation control method thereof, and relates to the technical field of methanol online reforming hydrogen production methanol / synthesis gas engines. The engine comprises a methanol storage tank, a gas-liquid secondary evaporator, a reactor, a separator, a synthesis gas component adjusting system, a gas compressor, a turbine, an engine gas inlet pipe, an engine cooling water way, a methanol common rail pipe, a methanol injection valve, an engine cylinder and an engine exhaust pipe. Methanol synthesis gas component adjustment is carried out by utilizing methanol hydrolysis hydrogen production and combining combustion waste gas, hydrogen and carbon dioxide are provided for a methanol engine, and the problems that hydrogen fuel is difficult to store and transport on a ship and the methanol engine is cold-started are solved; and the problem that the engine is prone to combustion instability during low load and is prone to knocking during high load is solved. The methanol / synthesis gas engine for hydrogen production through methanol online reforming and the operation control method of the methanol / synthesis gas engine are suitable for inland ships.

Description

Technical Field

[0001] The present invention relates to the technical field of methanol / syngas engines for online reforming of methanol to produce hydrogen, and in particular to a methanol / syngas engine for online reforming of methanol to produce hydrogen suitable for inland vessels and an operation control method thereof. Background Art

[0002] Methanol, a low-carbon, easily synthesized fuel, is one of the best ways to achieve deep carbon emissions reductions in the marine sector. However, methanol has a high latent heat of vaporization and a slow combustion rate, leading to incomplete combustion in spark-ignition methanol engines, resulting in reduced thermal efficiency and increased unconventional emissions. Currently, methanol engines suffer from cold start issues, combustion instability at low loads, and detonation at high loads, limiting their practical application in the marine sector.

[0003] Hydrogen has a fast combustion rate and low ignition energy. Blending it with methanol can significantly improve the cold start problem of methanol engines, and can also improve the unstable combustion of methanol at low loads, achieving more efficient combustion of methanol, and can also reduce the generation of unconventional emissions, and improve the engine's power performance, economic performance, and emission performance.

[0004] The liquefaction temperature of hydrogen at standard atmospheric pressure is -252.76°C, making liquefaction conditions extremely stringent. Furthermore, at this temperature, some impurities condense into solid particles, requiring extremely high hydrogen purity for practical applications. Consequently, the liquefaction and purification of hydrogen requires significant energy and expense, significantly limiting its use on ships.

[0005] Carbon dioxide can significantly suppress the knock tendency of engines and is an effective means of resolving engine knock. Therefore, it is urgent to solve the problem of hydrogen application on board ships and to combine hydrogen and carbon dioxide to solve the problems faced by methanol engines with different loads. Summary of the Invention

[0006] The present invention utilizes methanol hydrolysis to produce hydrogen, and combines the combustion exhaust gas to adjust the methanol synthesis gas composition, providing hydrogen and carbon dioxide for the methanol engine, solving the problems of difficulty in storing and transporting hydrogen fuel on board, cold start of methanol engine, and the problem that the engine is prone to combustion instability at low load and detonation at high load. Methanol is a low-carbon, easily synthesized fuel, and is considered to be one of the best ways to achieve deep carbon emission reduction in the shipping field. However, methanol engines have cold start problems, and are prone to combustion instability at low load and detonation at high load. Therefore, hydrogen is used to improve the combustion and emission characteristics of methanol engines, and carbon dioxide is used to suppress engine knock. In addition, the storage and transportation problem of hydrogen on ships is difficult to solve. Therefore, the present invention discloses a methanol / synthesis gas engine suitable for inland ships to produce hydrogen through online reforming of methanol and a method for controlling its operation.

[0007] To achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a methanol / synthesis gas engine for inland waterway vessels to produce hydrogen through online methanol reforming, comprising a methanol storage tank, a gas-liquid secondary evaporator, a reactor, a separator, a synthesis gas composition adjustment system, a compressor, a turbine, an engine intake pipe, an engine cooling water circuit, a methanol common rail pipe, a methanol injection valve, an engine cylinder, and an engine exhaust pipe; A submersible pump is installed in the methanol storage tank, which is connected to the inlet of the gas-liquid secondary evaporator and mixes with the engine's high-temperature cooling water to form a methanol-water solution; The gas-liquid secondary evaporator is used to vaporize the methanol-water solution and send it to the reactor. It is also used to exchange heat between the hydrogen-rich synthesis gas output from the separator and the methanol-water solution, and to deliver the low-temperature synthesis gas after heat exchange to the synthesis gas composition adjustment system; The reactor is used to hydrolyze the methanol-water solution steam to generate hydrogen-rich synthetic steam containing water vapor, and the hydrogen-rich synthetic steam is transported to the separator; The separator is used to separate water vapor from hydrogen-rich synthesis gas, and recycle the water vapor to the reactor to complete the hydrolysis reaction, and also transport the hydrogen-rich synthesis gas to the gas-liquid secondary evaporator; The syngas composition adjustment system includes a purifier and a mixer, which are used to adjust the ratio of hydrogen and carbon dioxide in the syngas and deliver the adjusted syngas to the engine intake pipe, where it is premixed with the air pressurized by the compressor. The engine intake pipe is used to deliver the premixed synthesis gas / air into the engine cylinder, and mix and burn it with methanol through the methanol common rail pipe and methanol injection valve in the engine cylinder; The high-temperature exhaust gas after combustion enters the turbine through the engine exhaust pipe to perform work. Part of the low-temperature combustion exhaust gas after work enters the synthesis gas composition adjustment system to participate in the synthesis gas composition adjustment, and part enters the reactor to provide energy for the hydrolysis reaction; After the combustion of the engine fuel, part of the energy is taken away by the low-temperature cooling water in the engine cooling water circuit to form high-temperature cooling water; part of the high-temperature cooling water is mixed with methanol to form a methanol-water solution, and the remaining part is heat exchanged through the gas-liquid secondary evaporator heat exchange fluid inlet. After heat exchange, the high-temperature cooling water becomes low-temperature cooling water again and enters the engine cooling water circuit again.

[0008] Furthermore, in a preferred embodiment, an automatic heating device is provided in the reactor for performing auxiliary heating when the residual heat of the engine exhaust turbine is insufficient.

[0009] Furthermore, in a preferred embodiment, the synthesis gas composition adjustment system includes a purifier and a mixer; The purifier is used to reduce the volume fraction of carbon dioxide in the low-temperature synthesis gas; The mixer is used to adjust the volume fraction of hydrogen and carbon dioxide from 0-100%.

[0010] Furthermore, there is a preferred embodiment in which the above-mentioned mixer is provided with three gas inlets and one gas outlet, the first gas inlet is the engine combustion exhaust gas inlet, the second gas inlet is connected to the purifier outlet, and the third gas inlet is directly connected to the hydrogen-rich reforming gas. By adjusting the opening and closing of the three gas inlets, the volume fraction of both hydrogen and carbon dioxide components can be adjusted from 0-100%.

[0011] Furthermore, there is a preferred embodiment, if the proportion of hydrogen in the mixed gas needs to be higher than the hydrogen-rich reformed gas separated by the separator, the first and third gas inlets are closed and the second gas inlet is opened.

[0012] Furthermore, in a preferred embodiment, if the proportion of carbon dioxide in the required mixed gas is higher than the hydrogen-rich reformed gas separated by the separator, the second gas inlet is closed and the first and third gas inlets are opened.

[0013] Furthermore, in a preferred embodiment, the energy for the hydrolysis reaction in the reactor is provided by the low-temperature combustion exhaust gas flowing out of the turbine.

[0014] Furthermore, there is a preferred embodiment, further comprising a three-way valve; The high-temperature cooling water flows into the gas-liquid secondary evaporator through the three-way valve.

[0015] Furthermore, there is a preferred embodiment in which the above-mentioned gas-liquid secondary evaporator is a secondary heat exchange evaporator, and a part of the engine high-temperature cooling water flowing out through the three-way valve and the liquid methanol enter the cold fluid flow channel of the gas-liquid secondary evaporator together to mix to form a methanol-water solution, and first exchanges heat with the engine high-temperature cooling water flowing out through the three-way valve and entering the hot fluid flow channel of the first-stage evaporator of the gas-liquid secondary evaporator, and then the methanol-water solution after heat exchange through the first-stage evaporator enters the cold fluid channel of the second-stage evaporator of the gas-liquid secondary evaporator again, and undergoes secondary heat exchange with the high-temperature reformed gas flowing out of the separator and boils to form methanol-water solution vapor.

[0016] In a second aspect, the present invention further provides an operation control method for a methanol / synthesis gas engine for inland waterway vessels using methanol online reforming to produce hydrogen, based on the above-mentioned method. The control method is as follows: Calculating the engine load and querying the synthesis gas blending ratio and the hydrogen gas volume fraction in the synthesis gas under the load; Determine whether the amount of synthesis gas meets the blending ratio requirements; If not, determine whether the turbine exhaust gas energy in the reactor is sufficient. If not, start the auxiliary heating system. If sufficient, increase the reactant flow in the reactor. If satisfied, determine whether the syngas hydrogen volume fraction required by the engine under the load condition is greater than 75%; If it is greater than, increase the hydrogen gas volume fraction in the synthesis gas; If it is less than, the volume fraction of carbon dioxide in the synthesis gas is increased.

[0017] Furthermore, in a preferred embodiment, the engine control system calculates the engine load based on the rotational speed and output power.

[0018] Furthermore, there is a preferred embodiment, which obtains the synthesis gas blending ratio and the hydrogen gas volume fraction in the synthesis gas under the load by looking up a table or calculating the load.

[0019] Furthermore, there is a preferred embodiment. If the hydrogen volume fraction of the synthesis gas is greater than 75%, it means that the engine requires a higher hydrogen volume fraction in the synthesis gas under this load condition to improve the combustion and emission characteristics and combustion instability of the methanol engine. The purifier is started, the mixer gas inlet 2 is opened, and the mixer gas inlets 1 and 3 are closed to increase the hydrogen volume fraction in the synthesis gas through the purifier; if the hydrogen volume fraction of the synthesis gas is less than 75%, it means that the engine requires a higher carbon dioxide volume fraction in the synthesis gas to suppress the knock phenomenon and knock intensity of the methanol engine. The purifier is closed, the mixer gas inlet 2 is closed, and the mixer gas inlets 1 and 3 are opened. The engine combustion exhaust gas is used to adjust the proportion of carbon dioxide components to increase the carbon dioxide volume fraction in the synthesis gas.

[0020] The beneficial effects of the present invention are: The present invention utilizes methanol hydrolysis to produce hydrogen, and combines it with combustion exhaust gas to adjust the composition of methanol synthesis gas, thereby providing hydrogen and carbon dioxide for the methanol engine, solving the problems of difficult storage and transportation of hydrogen fuel on board, cold start of methanol engine, and the problems of unstable combustion at low load and detonation at high load.

[0021] Furthermore, the engine can adjust the volume fractions of both hydrogen and carbon dioxide in the syngas from 0-100%, enabling the blending of syngas according to the varying operating requirements of the methanol engine. Under high-load conditions, the hydrogen content in the syngas is reduced and the carbon dioxide content is increased, suppressing the methanol engine's knock tendency and reducing knock intensity at full load. At low loads, the hydrogen content is increased and the carbon dioxide content is reduced, improving methanol combustion and addressing cold start issues and low-load combustion instability. Furthermore, hydrogen blending itself can enhance the power, fuel economy, and emissions performance of the methanol engine.

[0022] Furthermore, the present invention makes full use of the heat of the engine's high-temperature cooling water, the thermal energy of the methanol reforming gas and the engine's waste heat, while improving energy utilization and achieving a rapid reduction in the temperature of the engine's high-temperature synthesis gas, so that it can meet the temperature requirements of the methanol engine synthesis gas mixing, and also achieves a rapid reduction in the temperature of the engine's high-temperature cooling water, which is beneficial to the efficient operation of the engine cooling system.

[0023] The present invention is applicable to a methanol / synthesis gas engine for producing hydrogen through online reforming of methanol on inland waterways and an operation control method thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a system structure diagram of a methanol / synthesis gas engine suitable for inland waterway vessels using methanol online reforming to produce hydrogen, as described in the present invention; Figure 2 The present invention is a flow chart of the operation control method of a methanol / synthesis gas engine for online reforming of methanol to produce hydrogen on inland waterways vessels.

[0026] Among them, 1 represents a submersible pump, 2 represents a methanol storage tank, 3 represents a methanol stop valve, 4 represents a methanol stop valve, 5 represents a gas-liquid secondary evaporator, 6 represents a reactor, 7 represents an automatic heating device, 8 represents a separator, 9 represents a purifier, 10 represents a mixer, 11 represents a synthesis gas composition adjustment system, 12 represents a compressor, 13 represents a turbine, 14 represents an engine intake pipe, 15 represents an engine cooling water circuit, 16 represents a methanol common rail pipe, 17 represents a methanol injection valve, 18 represents an engine cylinder, 19 represents an engine exhaust pipe, and 20 represents a three-way valve. DETAILED DESCRIPTION

[0027] In the following description, the specific implementation details of "a methanol / synthesis gas engine suitable for online reforming of methanol to produce hydrogen for inland ships and its operation control method" provided in this specification, such as experimental equipment, operating procedures, data processing steps and example parameters, are for illustrative purposes rather than restrictive definitions, and are intended to help those skilled in the art to thoroughly understand the principles and implementation of the present invention; however, those skilled in the art should be clear that these details only represent one of the feasible embodiments, and the core concept of the present invention can be fully realized by other technical means or alternative solutions that are not fully described without departing from its spirit, and the omission of conventional experimental methods and device details known in the art in the specification is to avoid redundant information interfering with the understanding of the innovation points. This does not mean that these known technologies are not required for implementation, and technical personnel should be able to supplement and apply them on their own based on professional knowledge.

[0028] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The following embodiments will help those skilled in the art further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that those skilled in the art may make various changes and improvements without departing from the scope of the present invention, and these are all within the scope of protection of the present invention.

[0029] Implementation Method 1: Combination Figure 1 This embodiment describes methanol, a low-carbon, easily synthesized fuel considered one of the best ways to achieve deep carbon emissions reductions in the marine sector. However, methanol engines suffer from cold start issues, are prone to combustion instability at low loads, and are prone to detonation at high loads. Therefore, this embodiment provides a methanol / syngas engine suitable for inland waterway vessels that uses methanol for online reforming and hydrogen production. This utilizes hydrogen to improve the combustion and emission characteristics of the methanol engine, while carbon dioxide is used to suppress engine detonation. Furthermore, the storage and transportation of hydrogen onboard ships is difficult to resolve. Therefore, this embodiment utilizes a methanol hydrolysis hydrogen production system that can produce hydrogen online based on real-time demand, resolving the difficulties associated with hydrogen storage and transportation onboard ships.

[0030] like Figure 1As shown, the methanol / syngas engine for online reforming of methanol to produce hydrogen on inland vessels proposed in this embodiment includes a methanol storage tank 2, a gas-liquid secondary evaporator 5, a reactor 6, a separator 8, a syngas composition adjustment system 11, a compressor 12, a turbine 13, an engine intake pipe 14, an engine cooling water circuit 15, a methanol common rail pipe 16, a methanol injection valve 17, an engine cylinder 18, and an engine exhaust pipe 19; The methanol storage tank 2 is provided with a submerged pump 1, which is connected to the inlet end of the gas-liquid secondary evaporator 5 and mixes with the engine high-temperature cooling water to form a methanol-water solution; The gas-liquid secondary evaporator 5 is used to vaporize the methanol-water solution and send it to the reactor 6. It is also used to exchange heat between the hydrogen-rich synthesis gas output from the separator 8 and the methanol-water solution, and to deliver the low-temperature synthesis gas after heat exchange to the synthesis gas composition adjustment system 11. The reactor 6 is used to hydrolyze the methanol-water solution vapor to generate hydrogen-rich synthetic steam containing water vapor, and the hydrogen-rich synthetic steam is transported to the separator 8; The separator 8 is used to separate the water vapor from the hydrogen-rich synthesis gas, and recycle the water vapor to the reactor 6 to complete the hydrolysis reaction, and also to transport the hydrogen-rich synthesis gas to the gas-liquid secondary evaporator 5; The syngas composition adjustment system 11 is used to adjust the ratio of hydrogen and carbon dioxide in the syngas and deliver the adjusted syngas to the engine intake pipe 14, where it is premixed with the air pressurized by the compressor 12; The engine intake pipe 14 is used to deliver the premixed synthesis gas / air into the engine cylinder 18, and the premixed synthesis gas / air is mixed and burned with the methanol via the methanol common rail pipe 16 and the methanol injection valve 17 in the engine cylinder 18; The high-temperature exhaust gas after combustion enters the turbine 13 through the engine exhaust pipe 19 to perform work. Part of the low-temperature combustion exhaust gas after work enters the synthesis gas composition adjustment system 11 to participate in the synthesis gas composition adjustment, and part enters the reactor 6 to provide energy for the hydrolysis reaction; After the combustion of the engine fuel, part of the energy is taken away by the low-temperature cooling water in the engine cooling water path 15 to form high-temperature cooling water; A portion of the high-temperature cooling water is mixed with methanol to form a methanol-water solution, and the remaining portion is heat exchanged through the heat exchange fluid inlet of the gas-liquid secondary evaporator 5. After heat exchange, the high-temperature cooling water becomes low-temperature cooling water again and enters the engine cooling water circuit 15 again.

[0031] In practical application, this embodiment involves the methanol liquid entering the gas-liquid secondary evaporator 5 via the submersible pump 1. It mixes with a portion of the high-temperature water from the methanol engine to form a methanol-water solution. The methanol-water solution is then vaporized into methanol-water vapor using the remaining high-temperature water and high-temperature syngas from the methanol engine. The methanol-water vapor enters the reactor 6, where a hydrolysis reaction occurs to produce hydrogen-rich syngas. This hydrogen-rich syngas is then separated from the remaining water vapor by a separator 8. The separated hydrogen-rich syngas enters the gas-liquid secondary evaporator 5 again for heat exchange with the methanol-water solution. The low-temperature syngas after heat exchange enters the syngas composition adjustment system 11, which adjusts the syngas composition according to the blending requirements of the methanol engine. The syngas composition adjustment system 11 consists of a purifier 9 and a mixer 10. The purifier converts the syngas into high-purity hydrogen, while the mixer introduces a portion of the combustion exhaust gas. By varying the ratio of hydrogen and carbon dioxide, the mass fractions of these components can be adjusted from 0% to 100%. The conditioned syngas enters the methanol engine for mixed combustion with methanol. The hydrogen in the syngas effectively improves the combustion process, while the carbon dioxide reduces the knock tendency of the methanol engine. The high-temperature exhaust gas after combustion first enters the turbine 13 to perform work. The low-temperature exhaust gas then enters the reactor 6 for secondary heat exchange, maintaining the methanol hydrolysis reaction temperature, before being discharged into the atmosphere. The methanol evaporation energy is derived from the high-temperature cooling water and syngas of the methanol engine, utilizing waste heat while also rapidly cooling the engine cooling water and syngas. The evaporation energy of the methanol-water solution (methanol boiling temperature is approximately 60°C) is primarily derived from the high-temperature circulating water (80-100°C) of the methanol engine and the hydrogen-rich reformed gas (approximately 200°C), enabling rapid methanol vaporization and cooling of the engine circulating water and hydrogen-rich reformed gas. The energy for the methanol hydrolysis process is provided by the exhaust gas after the methanol engine turbine. The methanol hydrolysis reaction temperature is approximately 200-250°C, and the exhaust gas temperature after the methanol engine turbine is between 280-350°C. In addition, an automatic heating device 7 is arranged in the reactor 6, which can assist in heating when the residual heat of the engine exhaust turbine is insufficient.

[0032] Implementation Method 2: Combination Figure 1 This embodiment is described as follows: This embodiment specifically describes the structure of a methanol / synthesis gas engine suitable for inland waterway vessels for online reforming of methanol to produce hydrogen as described in the first embodiment; like Figure 1As shown, the structure is more specifically as follows: it includes a submersible pump 1, a methanol storage tank 2, a methanol stop valve 3, a methanol stop valve 4, a gas-liquid secondary evaporator 5, a reactor 6, an automatic heating device 7, a separator 8, a purifier 9, a mixer 10, a synthesis gas composition adjustment system 11, a compressor 12, a turbine 13, an engine intake pipe 14, an engine cooling water circuit 15, a methanol common rail pipe 16, a methanol injection valve 17, an engine cylinder 18, an engine exhaust pipe 19, a three-way valve 20 and connecting pipes, etc.

[0033] A submersible pump 1 is arranged inside the methanol storage tank 2. The submersible pump 1 is connected to the methanol inlet end of the gas-liquid secondary evaporator 5 through a pipeline, and is mixed with the high-temperature engine cooling water bypassed through the three-way valve 20 to form a methanol-water solution. The vaporized methanol-water solution flows into the reactor 6 from the outlet end of the gas-liquid secondary evaporator 5. The methanol-water solution vapor undergoes a hydrolysis reaction in the reactor 6 to generate hydrogen-rich synthesis steam containing water vapor. The hydrogen-rich synthesis steam flows into the separator 8 to separate the water vapor from the hydrogen-rich synthesis gas. The water vapor circulates and flows into the reactor 6 again to continue the hydrolysis reaction. The hydrogen-rich synthesis gas flows into the gas-liquid secondary evaporator 5 to exchange heat with the methanol-water solution. The low-temperature synthesis gas after heat exchange enters the synthesis gas composition adjustment system 11. The synthesis gas composition adjustment system 11 includes a purifier 9 and a mixer 10. The adjusted synthesis gas enters the methanol The methanol is then premixed with air, supercharged by compressor 12, and enters engine cylinder 18. The mixture is then mixed with methanol fed through methanol common rail 16 and methanol injection valve 17 for combustion. The high-temperature exhaust gas from combustion enters turbine 13 through exhaust pipe 19 to perform work. A portion of the low-temperature combustion exhaust gas from this work continues to enter syngas composition adjustment system 11 to adjust the syngas composition, while a portion enters reactor 6 to provide energy for the methanol hydrolysis reaction before entering the atmosphere. Reactor 6 is equipped with an automatic heating device 7 to provide auxiliary heating when the engine exhaust turbine is insufficient. A portion of the energy from the engine combustion is removed by low-temperature cooling water in engine cooling water circuit 15, forming high-temperature cooling water. The outlet of the high-temperature cooling water circuit is connected to the inlet of three-way valve 20. Three-way valve 20 bypasses a portion of the high-temperature cooling water to the reactant inlet of gas-liquid secondary evaporator 5 to form a methanol-water solution, while the remaining portion is diverted to the heat exchange fluid inlet of gas-liquid secondary evaporator 5 for heat exchange. After heat exchange, the high-temperature cooling water is converted back into low-temperature cooling water and re-enters the engine cooling water circulation system.

[0034] Furthermore, the gas-liquid secondary evaporator 5 is a two-stage heat exchange evaporator. A portion of the engine's high-temperature cooling water flowing out through the three-way valve 20 and liquid methanol (methanol boiling temperature is approximately 60°C) enter the cold fluid flow channel of the gas-liquid secondary evaporator 5, mixing to form a methanol-water solution. This solution then undergoes heat exchange with the engine's high-temperature cooling water (80-100°C) flowing out through the three-way valve 20 and into the hot fluid flow channel of the first-stage evaporator of the gas-liquid secondary evaporator 5. After heat exchange in the first-stage evaporator, the methanol-water solution enters the cold fluid channel of the second-stage evaporator 5 again, undergoing a secondary heat exchange with the high-temperature reformed gas (approximately 200°C) flowing out of the separator 8, and boils to form methanol-water solution vapor.

[0035] Furthermore, the methanol-water vapor generated by the gas-liquid secondary evaporator 5 undergoes a hydrolysis reaction in reactor 6 to produce hydrogen-rich reformed gas. Energy for the hydrolysis process is provided by the low-temperature combustion exhaust gas flowing out of turbine 13. The methanol hydrolysis reaction temperature is approximately 200-250°C, and the temperature of the low-temperature combustion exhaust gas after the methanol engine turbine is between 280-350°C. Furthermore, an automatic heating device 8 is located within reactor 7 to provide auxiliary heating when the engine exhaust turbine is insufficiently heated.

[0036] Furthermore, the syngas composition adjustment system 11 includes two devices: a purifier 9 and a mixer 10. The hydrogen-rich reformed gas separated by separator 8 primarily consists of hydrogen and carbon dioxide (ideally, a volume fraction of 75% hydrogen and 25% carbon dioxide). Purifier 9 absorbs or selectively filters the carbon dioxide in the hydrogen-rich reformed gas, reducing the carbon dioxide volume fraction and increasing the hydrogen content of the syngas, achieving a composition adjustment of 75%-100% hydrogen and 0-25% carbon dioxide in the syngas. Mixer 10 has three gas inlets and one gas outlet. The first gas inlet is for engine combustion exhaust gas, the second gas inlet is connected to the outlet of purifier 9, and the third gas inlet is directly connected to the hydrogen-rich reformed gas. If the engine requires a higher hydrogen content in the mixed gas than the hydrogen-rich reformed gas separated by separator 8, channels 1 and 3 are closed, channel 2 is opened, and the purifier provides the syngas with a higher hydrogen content. If the engine requires a higher CO2 content in the mixed gas than the hydrogen-rich reformed gas separated by separator 8, channel 2 is closed, and channels 1 and 3 are opened. The engine exhaust gas is then used to adjust the CO2 content, achieving a CO2 volume fraction of 25%-100% and a hydrogen content of 0-75%. Together, these two functions allow for a 0-100% adjustment of the hydrogen and CO2 volume fractions.

[0037] Furthermore, the syngas flowing out of the syngas composition adjustment system 11 is mixed with air pressurized by the compressor 12 to form a combustible mixture that enters the engine cylinder 18. This mixture is then blended with the methanol injected via the methanol common rail 16 and the methanol injection valve 17 for combustion. The hydrogen in the syngas burns faster, effectively improving methanol combustion and addressing cold start issues and low-load combustion instability in the methanol engine. The carbon dioxide, on the other hand, suppresses the methanol engine's knock tendency and reduces knock intensity at full load. This blended combustion results in improved power, fuel economy, and emissions performance for the methanol engine.

[0038] Furthermore, a portion of the high-temperature cooling water flowing out of the methanol engine cooling water path 15 mixes with methanol to form a methanol-water solution, forming methanol-water vapor, which ultimately enters the reactor as a feedstock for the methanol hydrolysis reaction. The remaining portion of the high-temperature cooling water serves as the hot fluid for the first-stage evaporator in the gas-liquid secondary evaporator 5. The gas-liquid secondary evaporator 5 is a two-stage heat exchange evaporator. A portion of the high-temperature engine cooling water flowing out through the three-way valve 20 and liquid methanol (methanol boiling at approximately 60°C) enter the cold fluid channel of the gas-liquid secondary evaporator 5, mixing to form a methanol-water solution. This solution initially undergoes heat exchange with the high-temperature engine cooling water (80-100°C) flowing out through the three-way valve 20 and into the hot fluid channel of the first-stage gas-liquid secondary evaporator 5. After heat exchange in the first-stage evaporator, the methanol-water solution enters the cold fluid channel of the second-stage gas-liquid secondary evaporator 5 again, undergoing a secondary heat exchange with the high-temperature reformed gas (approximately 200°C) flowing out of the separator 8, boiling to form methanol-water vapor.

[0039] To sum up, the methanol / synthesis gas engine proposed in this embodiment is suitable for inland ships to produce hydrogen through online reforming of methanol. It produces hydrogen by utilizing methanol hydrolysis and adjusts the composition of methanol synthesis gas in combination with combustion exhaust gas to provide hydrogen and carbon dioxide for the methanol engine, thereby solving the problems of difficulty in storage and transportation of hydrogen fuel on board, cold start of methanol engine, and the problems of unstable combustion at low load and detonation at high load.

[0040] Furthermore, the engine can adjust the volume fractions of both hydrogen and carbon dioxide in the syngas from 0-100%, enabling the blending of syngas according to the varying operating requirements of the methanol engine. Under high-load conditions, the hydrogen content in the syngas is reduced and the carbon dioxide content is increased, suppressing the methanol engine's knock tendency and reducing knock intensity at full load. At low loads, the hydrogen content is increased and the carbon dioxide content is reduced, improving methanol combustion and addressing cold start issues and low-load combustion instability. Furthermore, hydrogen blending itself can enhance the power, fuel economy, and emissions performance of the methanol engine.

[0041] Furthermore, the engine makes full use of the heat of the engine's high-temperature cooling water, the thermal energy of the methanol reforming gas and the engine's waste heat. While improving energy utilization, it also achieves a rapid reduction in the temperature of the engine's high-temperature synthesis gas, enabling it to meet the temperature requirements of the methanol engine synthesis gas mixing. It also achieves a rapid reduction in the temperature of the engine's high-temperature cooling water, which is beneficial to the efficient operation of the engine's cooling system.

[0042] Implementation Method 3: Combination Figure 2 This embodiment provides an operation control method for a methanol / synthesis gas engine for online methanol reforming and hydrogen production on inland vessels based on the first or second embodiment. The operation control method includes the following steps: Step 1: Calculate the engine load and query the syngas blending ratio and hydrogen volume fraction in the syngas under the load; Step 2: Determine whether the amount of syngas meets the blending ratio requirement; Step 3: If not, determine whether the turbine exhaust gas energy in the reactor is sufficient. If not, start the auxiliary heating system. If sufficient, increase the reactant flow rate in the reactor. Step 4: If satisfied, determine whether the syngas hydrogen volume fraction required by the engine under the load condition is greater than 75%; Step 5: If it is greater than, increase the hydrogen gas volume fraction in the synthesis gas; Step 6: If it is less than, increase the volume fraction of carbon dioxide in the synthesis gas.

[0043] In actual operation, Figure 1 and Figure 2 As shown, the operation control method is specifically as follows: The engine control system calculates the engine load based on the speed and output power. It then uses a load lookup table or calculation to determine the syngas blending ratio and the hydrogen volume fraction in the syngas at that load. It then determines whether the syngas flow rate meets the required blending ratio for that load. If not, it then determines whether the turbine exhaust gas energy in reactor 6 is sufficient. If not, it activates the auxiliary heating system (automatic heating device 7). If sufficient, it indicates insufficient reactant feedstock entering reactor 6, and increases the reactant flow rate. If the syngas flow rate meets the required blending ratio, it proceeds to the next stage, determining whether the hydrogen volume fraction in the syngas required for the engine at that load condition is greater than 75%. If the hydrogen volume fraction of the synthesis gas is greater than 75%, it means that the engine requires a higher hydrogen volume fraction in the synthesis gas under this load condition to improve the combustion and emission characteristics and combustion instability of the methanol engine. The purifier 9 is started, the gas inlet 2 of the mixer 10 is opened, and the gas inlets 1 and 3 of the mixer are closed to increase the hydrogen volume fraction in the synthesis gas through the purifier 9; if the hydrogen volume fraction of the synthesis gas is less than 75%, it means that the engine requires a higher carbon dioxide volume fraction in the synthesis gas to suppress the knock phenomenon and knock intensity of the methanol engine. The purifier 9 is closed, the gas inlet 2 of the mixer 10 is closed, and the gas inlets 1 and 3 of the mixer are opened. The proportion of carbon dioxide components is adjusted using the engine combustion exhaust gas to increase the carbon dioxide volume fraction in the synthesis gas.

[0044] In the above description, it should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections.

[0045] It should also be understood that in the description of this specification, the reference terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" and the like mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0046] The foregoing description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of the claims.

Claims

1. A methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production, characterized in that: It includes a methanol storage tank (2), a gas-liquid secondary evaporator (5), a reactor (6), a separator (8), a synthesis gas composition adjustment system (11), a compressor (12), a turbine (13), an engine intake pipe (14), an engine cooling water circuit (15), a methanol common rail pipe (16), a methanol injection valve (17), an engine cylinder (18) and an engine exhaust pipe (19); A submerged pump (1) is provided in the methanol storage tank (2), and the submerged pump (1) is connected to the inlet end of the gas-liquid secondary evaporator (5) and is mixed with the engine high-temperature cooling water to form a methanol-water solution; The gas-liquid secondary evaporator (5) is used to vaporize the methanol-water solution and send it to the reactor (6), and is also used to exchange heat between the hydrogen-rich synthesis gas output from the separator (8) and the methanol-water solution, and to transport the low-temperature synthesis gas after heat exchange to the synthesis gas composition adjustment system (11); The reactor (6) is used to hydrolyze the methanol-water solution steam to generate hydrogen-rich synthesis steam containing water vapor, and the hydrogen-rich synthesis steam is transported to the separator (8); The separator (8) is used to separate the water vapor from the hydrogen-rich synthesis gas, and recycle the water vapor to the reactor (6) to complete the hydrolysis reaction, and also to transport the hydrogen-rich synthesis gas to the gas-liquid secondary evaporator (5); The synthesis gas composition adjustment system (11) is used to adjust the ratio of hydrogen and carbon dioxide in the synthesis gas, and to deliver the adjusted synthesis gas to the engine intake pipe (14), and then premix it with the air pressurized by the compressor (12); The engine intake pipe (14) is used to deliver the premixed synthesis gas / air into the engine cylinder (18), and the premixed synthesis gas / air is mixed with the methanol via the methanol common rail pipe (16) and the methanol injection valve (17) and burned in the engine cylinder (18); The high-temperature exhaust gas after combustion enters the turbine (13) through the engine exhaust pipe (19) to perform work. A portion of the low-temperature combustion exhaust gas after the work enters the synthesis gas composition adjustment system (11) to participate in the synthesis gas composition adjustment, and a portion enters the reactor (6) to provide energy for the hydrolysis reaction. After the combustion of the engine fuel, part of the energy is taken away by the low-temperature cooling water in the engine cooling water circuit (15) to form high-temperature cooling water; A portion of the high-temperature cooling water is mixed with methanol to form a methanol-water solution, and the remaining portion is heat exchanged through the heat exchange fluid inlet of the gas-liquid secondary evaporator (5). After the heat exchange, the high-temperature cooling water becomes low-temperature cooling water again and enters the engine cooling water circuit (15) again.

2. A methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production according to claim 1, characterized in that: An automatic heating device (7) is provided in the reactor (6) to realize an auxiliary heating function.

3. A methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production according to claim 1, characterized in that: The synthesis gas composition adjustment system (11) includes a purifier (9) and a mixer (10); The purifier (9) is used to reduce the volume fraction of carbon dioxide in the low-temperature synthesis gas; The mixer (10) is used to achieve the function of adjusting the volume fraction of hydrogen and carbon dioxide from 0 to 100%.

4. A methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production according to claim 3, characterized in that: The mixer (10) is provided with three gas inlets and one gas outlet. The first gas inlet is an inlet for engine combustion exhaust gas, the second gas inlet is connected to the outlet of the purifier (9), and the third gas inlet is connected to the hydrogen-rich reformed gas. By adjusting the opening and closing of the three gas inlets, the volume fraction of the components of hydrogen and carbon dioxide can be adjusted.

5. A methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production according to claim 4, characterized in that: When the first and third gas inlets are closed and the second gas inlet is opened, the proportion of hydrogen in the mixed gas is higher than that of the hydrogen-rich reformed gas separated by the separator (8).

6. A methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production according to claim 4, characterized in that: When the second gas inlet is closed and the first and third gas inlets are opened, the proportion of carbon dioxide in the mixed gas is higher than that of the hydrogen-rich reformed gas separated by the separator (8).

7. The methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production according to claim 1, characterized in that: The energy for the hydrolysis reaction in the reactor (6) is provided by the low-temperature combustion exhaust gas flowing out of the turbine (13).

8. The methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production according to claim 1, characterized in that: Also included is a three-way valve (20); The high-temperature cooling water flows into the gas-liquid secondary evaporator (5) through the three-way valve (20).

9. A methanol / synthesis gas engine suitable for inland waterway vessels for online methanol reforming and hydrogen production according to claim 8, characterized in that: The gas-liquid secondary evaporator (5) is a secondary heat exchange evaporator. A portion of the high-temperature cooling water flowing out through the three-way valve (20) and the liquid methanol enter the cold fluid flow channel of the gas-liquid secondary evaporator (5) together and mix to form a methanol-water solution, and exchanges heat with the high-temperature cooling water flowing out through the three-way valve (20) and entering the hot fluid flow channel of the first-stage evaporator of the gas-liquid secondary evaporator (5). The methanol-water solution after heat exchange in the first-stage evaporator enters the cold fluid channel of the second-stage evaporator of the gas-liquid secondary evaporator (5) again, exchanges heat with the high-temperature reformed gas flowing out of the separator (8) for a second time, and boils to form methanol-water solution steam.

10. The operation control method for a methanol / synthesis gas engine for inland waterway vessels using methanol online reforming to produce hydrogen according to any one of claims 1 to 9, characterized in that: The method is: Calculate the engine load and query the syngas blending ratio and hydrogen volume fraction in the syngas under the load; Determine whether the amount of synthesis gas meets the blending ratio requirements; If not, determine whether the turbine exhaust gas energy in the reactor is sufficient. If not, start the auxiliary heating system. If sufficient, increase the reactant flow in the reactor. If satisfied, determine whether the syngas hydrogen volume fraction required by the engine under the load condition is greater than 75%; If it is greater than, increase the hydrogen gas volume fraction in the synthesis gas; If it is less than, the volume fraction of carbon dioxide in the synthesis gas is increased.

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