CN-122014403-A - Organic liquid hydrogen storage combined hydrogen engine power system and method for coupling hydrogen afterburning

CN122014403ACN 122014403 ACN122014403 ACN 122014403ACN-122014403-A

Abstract

The invention discloses a coupling hydrogen afterburning organic liquid hydrogen storage combined hydrogen engine power system and a working method thereof, and belongs to the technical field of new energy automobile power systems. The system comprises an organic liquid hydrogen storage (LOHC) preheating subsystem, an LOHC dehydrogenation subsystem, a hydrogen separation and purification subsystem, a hydrogen internal combustion engine subsystem, a catalytic combustion energy supplementing subsystem, a cooling liquid subsystem and an electric heating and electric auxiliary hot start subsystem. The invention sequentially recovers the waste heat of the cooling liquid of the hydrogen internal combustion engine, the mixed gas after dehydrogenation and the tail gas after energy supply through the multistage heat exchange network, is used for preheating LOHC, utilizes a part of hydrogen to carry out catalytic combustion energy supplementing on the tail gas of the engine, takes the high-temperature tail gas as a main heat source of dehydrogenation reaction, and solves the contradiction between low temperature of the tail gas of the high-efficiency engine and high heat required by dehydrogenation. The system integrates a central control unit, and can intelligently coordinate subsystems according to working conditions. The invention obviously improves the comprehensive utilization efficiency of energy and ensures the cold start capability of the system.

Inventors

WEI XUTAO
WANG ZETAO
WANG JINHUA
ZHANG MENG
HUANG ZUOHUA

Assignees

西安交通大学

Dates

Publication Date: 20260512
Application Date: 20260303

Claims (10)

1. The power system is characterized by comprising an LOHC preheating subsystem, an LOHC dehydrogenation subsystem, a hydrogen purification and separation subsystem, a hydrogen internal combustion engine subsystem, a catalytic combustion energy supplementing subsystem, a cooling liquid subsystem and an electric heating and electric auxiliary hot-start subsystem; The LOHC preheating subsystem is used for preheating LOHC, the LOHC dehydrogenation reaction subsystem comprises a dehydrogenation reactor (7) for receiving the preheated LOHC and converting the preheated LOHC into dehydrogenated organic gaseous working medium and hydrogen through dehydrogenation reaction, the hydrogen purification and separation subsystem separates the dehydrogenated organic liquid from the hydrogen through secondary pressurization and recovers heat dissipated in a cooling process before separation, one part of the recovered heat enters the hydrogen internal combustion engine subsystem for combustion work, and the other part of the recovered heat enters the catalytic combustion energy supplementing subsystem for supplementing energy to tail gas; The hydrogen internal combustion engine subsystem converts the energy of hydrogen combustion into output work, and simultaneously generates high-temperature tail gas in the operation process, exchanges heat with hydrogen-rich organic liquid working medium in the dehydrogenation reactor (7) to supply energy for the dehydrogenation reaction; The electric heating and electric auxiliary hot start subsystem uses electric energy to assist in supplementing energy for the dehydrogenation reaction, and uses the electric energy to output power when the automobile is cold started.
2. The organic liquid hydrogen storage combined hydrogen engine power system coupled with hydrogen afterburning according to claim 1, wherein the LOHC preheating subsystem is used for carrying out three-stage preheating on LOHC and recovering heat of a cooling liquid of a hydrogen internal combustion engine, heat of a mixed gas of hydrogen after dehydrogenation and an organic gaseous working medium and heat of tail gas after energy supply; The LOHC preheating system comprises an oil tank (1), an organic liquid pump (2), a first heat exchanger (3), a second heat exchanger (4) and a third heat exchanger (5) which are sequentially connected in series, wherein a cold flow inlet of the first heat exchanger (3) is connected with an outlet of the oil tank (1), a cold flow outlet of the first heat exchanger (3) is connected with a cold flow inlet of the second heat exchanger (4), a cold flow outlet corresponding to the second heat exchanger (4) is connected with a cold flow inlet of the third heat exchanger (5), and a cold flow outlet corresponding to the third heat exchanger (5) is directly connected with the dehydrogenation reactor (7) or is connected with the dehydrogenation reactor through a heat conducting oil electric heater (6); The hydrogen generated by the reaction in the dehydrogenation reactor (7) and the dehydrogenated organic gaseous working medium mixed gas are connected with the heat flow inlet of the second heat exchanger (4) through the outlet of the dehydrogenation reactor (7), the heat flow outlet corresponding to the second heat exchanger (4) is connected with the heat flow inlet of the fourth heat exchanger (8), the cooling liquid of the internal combustion engine recovered by the waste heat of the hydrogen purification and separation subsystem is connected with the heat flow inlet of the first heat exchanger (3), and the tail gas after supplying energy to the dehydrogenation reactor (7) is connected with the heat flow inlet of the third heat exchanger (5).
3. The organic liquid hydrogen storage combined hydrogen engine power system coupled with hydrogen afterburning according to claim 1, wherein the hydrogen purification and separation subsystem comprises a fourth heat exchanger (8), a fifth heat exchanger (9), a first cooler (10), a first separator (11), a booster (12), a sixth heat exchanger (13), a second cooler (14), a second separator (15), a hydrogen permeable membrane (16) and a splitter (17); The hydrogen and the dehydrogenated organic gaseous working medium mixture enter a heat flow inlet of a heat exchanger IV (8), a heat flow outlet of the heat exchanger IV (8) is connected with a heat flow inlet of a heat exchanger IV (9), a heat flow outlet of the heat exchanger IV (9) is connected with an inlet of a cooler I (10), an outlet of the cooler I (10) is connected with an inlet of a separator I (11), a liquid phase outlet of the separator I (11) is communicated with an organic liquid storage tank, a gas phase outlet of the separator I (11) is connected with an inlet of a booster (12), an outlet of the booster (12) is connected with a heat flow inlet of a heat exchanger VI (13), a heat flow outlet of the heat exchanger VI (13) is connected with an inlet of a cooler II (14), an outlet of the cooler II (14) is connected with an inlet of a separator II (15), a liquid phase outlet of the separator II (15) is communicated with an organic liquid storage tank, a gas phase outlet of the separator II (15) is connected with an inlet of a hydrogen permeable membrane (16), an outlet of the hydrogen permeable membrane (16) is connected with a splitter (17), and an outlet of the splitter (17) is connected with an inlet of one of a catalytic mixture system of hydrogen and an inlet of an internal combustion system (25) of the hydrogen and one of the other catalytic mixture system.
4.A coupled hydrogen afterburning organic liquid hydrogen storage combined hydrogen engine power system according to claim 3, characterized in that said hydrogen purification and separation subsystem further comprises a hydrogen buffer tank (29), said hydrogen buffer tank (29) being arranged between the hydrogen permeable membrane (16) and the flow divider (17) for storing excess hydrogen after the vehicle is stopped.
5. An organic liquid hydrogen storage combined hydrogen engine power system coupled with hydrogen afterburning according to claim 1, characterized in that the hydrogen internal combustion engine subsystem comprises a turbocharger (18), a third cooler (19), a mixer (20), a compressor (21), a combustion chamber (22), an expander (23) and a compression turbine (24), wherein air enters the turbocharger (18), the outlet of the turbocharger (18) is connected with the inlet of the third cooler (19), the third cooler (19) is connected with one inlet of the mixer (20), the hydrogen and air premix is connected with the compressor (21) through the outlet of the mixer (20), the outlet of the compressor (21) is connected with the inlet of the combustion chamber (22), the tail gas generated by the hydrogen combustion is connected with the expander (23) through the outlet of the combustion chamber (22), the outlet of the expander (23) is connected with the inlet of the compression turbine (24), and the outlet of the compression turbine (24) is connected with the catalytic combustion tail gas energy compensator (25).
6. The organic liquid hydrogen storage combined hydrogen engine power system coupled with hydrogen afterburning according to claim 1, wherein the catalytic combustion energy supplementing subsystem comprises a catalytic combustion tail gas energy supplementing device (25), hydrogen and tail gas enter the catalytic combustion tail gas energy supplementing device (25) through two inlets respectively to be combusted, an outlet of the catalytic combustion tail gas energy supplementing device (25) is connected with the dehydrogenation reactor (7), and tail gas after being supplemented by the catalytic combustion tail gas energy supplementing device (25) is led into the dehydrogenation reactor (7) to supply energy for dehydrogenation reaction.
7. The organic liquid hydrogen storage combined hydrogen engine power system coupled with hydrogen afterburning according to claim 1, wherein the cooling water subsystem comprises a cooling water pump (26), a fourth cooler (27), a sixth heat exchanger (13), a fourth heat exchanger (8) and a first heat exchanger (3) which are sequentially connected in series, the hydrogen internal combustion engine is cooled by the fourth cooler (27), the mixed gas after dehydrogenation reaction is cooled by the sixth heat exchanger (13), and the LOHC is preheated by the heat exchanger (8) and the first heat exchanger (3) absorbed in the cooling process.
8. The organic liquid hydrogen storage combined hydrogen engine power system coupled with hydrogen afterburning according to claim 1, wherein the electric heating and electric auxiliary hot start subsystem comprises a power battery (31) and an electric auxiliary hot cold start device (32), one electric energy outlet of the power battery (31) directly outputs kinetic energy, the other electric energy outlet is connected with the electric auxiliary hot cold start device (32), and the electric auxiliary hot cold start device (32) performs electric heating energy supplementing on the dehydrogenation reactor (7) during cold start.
9. The coupled hydrogen afterburning organic liquid hydrogen storage combined hydrogen engine power system according to claim 1, further comprising a central main control unit (28) and an ECU engine control unit (30) for interacting information with each component of the system and performing working condition control to make the system operate under optimal working conditions; The central main control unit (28) is connected with the ECU engine control unit (30), the organic liquid pump (2), the cooling water pump (26), the power battery (31), the electric auxiliary hot and cold starting device (32), the dehydrogenation reactor (7), the heat conduction oil electric heater (6), the flow divider (17) and the catalytic combustion tail gas energy compensator (25) to monitor and control various parameters, and the ECU engine control unit (30) is connected with the turbocharger (18), the compressor (21), the combustion chamber (22) and the expander (23) to monitor and control various parameters of the engine.
10. A method of operating a coupled hydrogen afterburning organic liquid hydrogen storage integrated hydrogen engine power system as claimed in claim 1, wherein: When the engine is started, LOHC is preheated to the rated working temperature, an electric heating and electric auxiliary hot start subsystem supplies heat to a dehydrogenation reactor (7), the preheated LOHC reacts in the dehydrogenation reactor (7) to generate mixed gas of hydrogen and a hydrogen-poor organic working medium, the mixed gas is introduced into an LOHC preheating subsystem to preheat incoming LOHC, then the mixed gas is cooled by engine cooling liquid and hydrogen in sequence and then subjected to secondary pressurization separation through a hydrogen purification and separation subsystem, the separated hydrogen-poor organic working medium enters a storage tank to be recycled, part of the hydrogen enters a hydrogen internal combustion engine subsystem to burn and do work, combustion tail gas is led to a catalytic combustion energy supplementing subsystem, the other part of the hydrogen is directly led into the catalytic combustion energy supplementing subsystem, the mixed combustion is led to the dehydrogenation reactor (7) to supply energy, the tail gas after energy supply is led into the LOHC preheating subsystem to preheat the LOHC, and then the LOHC is discharged; After the engine is started, calculating to obtain the hydrogen flow required by the engine according to the required output power, controlling the air flow, compression ratio and discharge pressure of the optimal efficiency under the current power, calculating the LOHC flow under the optimal efficiency according to the required hydrogen flow, enabling the hydrogen flow entering the hydrogen internal combustion engine subsystem and the catalytic combustion energy supplementing subsystem to meet the optimal efficiency working condition, supplementing energy for the preheating and dehydrogenation process when the energy is insufficient, simultaneously utilizing the cooling liquid subsystem to cool the incoming flow to the temperature required by separation, controlling the cooling water flow to cool the engine to the proper temperature, and enabling the whole power system to operate under the optimal efficiency working condition; after the engine stops running, the LOHC is stopped being pumped out, and the generated hydrogen is temporarily stored.

Description

Organic liquid hydrogen storage combined hydrogen engine power system and method for coupling hydrogen afterburning Technical Field The invention relates to the technical field of hydrogen energy, in particular to a power system and a method of an organic liquid hydrogen storage combined hydrogen engine for coupling hydrogen afterburning. Background In the face of carbon dioxide emission reduction requirements, the adoption of the carbon-free fuel in the field of vehicles is an effective solving way. Hydrogen is used as an excellent renewable energy carrier, is the most potential zero-carbon energy source, and has the unique advantages of wide availability, high quality energy density and the like. However, the in-vehicle application of hydrogen has always faced serious safety challenges. The hydrogen storage system has small molecular size, low viscosity, wider flammable range and lower ignition energy, so that the hydrogen storage system is easier to cause leakage and combustion risk in a vehicle-mounted high-pressure or low-temperature environment, and the safety challenge which needs to be solved in design and application of the vehicle-mounted hydrogen storage system is formed. The main current vehicle-mounted hydrogen storage method mainly comprises high-pressure gas hydrogen storage, wherein the vehicle-mounted high-pressure hydrogen storage bottle stores 39 g of hydrogen per liter under the pressure of 70 MPa g. The current industry mainly adopts a 35 MPa hydrogen storage bottle, the hydrogen storage amount per liter is only about 20-22 g, and potential safety hazards such as hydrogen leakage and explosion exist. In contrast, organic liquid hydrogen storage (LOHC) technology provides an emerging path with high safety, high volumetric hydrogen storage density and strong engineering compatibility for vehicle-mounted hydrogen energy systems. The organic liquid hydrogen storage technology mainly relies on reversible hydrogenation and dehydrogenation reactions of specific unsaturated organic carriers to realize stable storage and on-demand release of hydrogen at a chemical bond layer. The water-soluble fiber is in a liquid state in a normal state, and can be safely stored and transported under normal pressure and normal temperature. The organic liquid hydrogen storage has the characteristics of reversible reaction process and high hydrogen storage density, and is safe and convenient to store and transport, suitable for long-distance transportation, and perfectly compatible with the existing oil infrastructure such as gasoline conveying pipelines, gas stations and the like. Meanwhile, the organic liquid hydrogen storage has the problems that the condition of LOHC (liquid organic hydrogen carrier) dehydrogenation reaction is harsh, high-temperature heating catalysis is needed, the consumed energy is large, and meanwhile, stable heat is needed to ensure the purity and yield of the product. If all of the external heat sources are relied upon, this can result in reduced system efficiency. In the working process of the hydrogen internal combustion engine, the hydrogen and oxygen in the air are subjected to combustion reaction, and the exhaust temperature can reach 500 ℃. Meanwhile, the internal combustion engine is usually cooled by cooling liquid, and the cooling liquid exchanges heat with the outside air to realize heat dissipation. The heat dissipated by the directly discharged high-temperature tail gas and the cooling liquid accounts for about 50% of the total energy released by the combustion of the fuel of the hydrogen internal combustion engine. This portion of the heat, if not recycled, would result in significant energy waste. At the system integration level, the LOHC and the hydrogen internal combustion engine have remarkable heat synergistic potential, namely, the heat required by the dehydrogenation process can be partially provided by the waste heat of the hydrogen internal combustion engine, and the energy of the LOHC and the hydrogen internal combustion engine can be well matched, so that the energy utilization efficiency of the whole vehicle is improved On the basis, the traditional engine is pursued to have high heat efficiency, the exhaust temperature is lower, and the engine needs power output and supplies heat to the hydrogen supply device under the power system of the coupled air supply system. The engine thermodynamic cycle adjustment concept is different from the traditional goal and needs to be designed. In summary, the mainstream high-pressure gaseous hydrogen storage presents a major safety risk. The high-density and high-safety organic liquid hydrogen storage technology requires a stable heat source in the use process, the dehydrogenation efficiency is low due to the fact that the heat source is not stable enough in the system of the existing LOHC combined internal combustion engine, and meanwhile, the system efficiency is low due to the fact that the residual heat of each part of th