Hydrogen energy purification system for coal gas

Abstract

The utility model discloses a coal gas purification hydrogen energy system which comprises a hydrogen purification system, a combined heat and power supply system, a fuel cell system, a first storage battery, a second storage battery, a first inverter, a second inverter and a heat exchange unit, an inlet of the hydrogen purification system is communicated with a raw material coal gas end, and a hydrogen end of the hydrogen purification system is communicated with the fuel cell system. The direct current end of the fuel cell system is communicated with the first inverter and the first storage battery, the tail gas end of the hydrogen purification system is communicated with the combined heat and power system, the inlet of the combined heat and power system is communicated with the raw material gas end, the alternating current end of the combined heat and power system is communicated with the second inverter, and the second inverter is communicated with the second storage battery; the heat source end of the cogeneration system communicates with the heat exchange unit. The system for purifying hydrogen energy from coal gas is suitable for coal gas in Hong Kong of China, has the effect of environmental protection, improves the heating energy efficiency of hydrogen energy, is advanced in integrated development and matched with electric energy storage, and increases the applicable configuration of a standby power supply.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of coal gas treatment especially relates to a coal gas purification hydrogen energy system. BACKGROUND

[0002] Hong Kong city pipeline gas is the coal gas provided by Hong Kong Chinese coal gas company, and about 50% of its composition is hydrogen. Therefore, a system extracts hydrogen in the coal gas for power generation, thereby playing the role of energy saving and environmental protection. UTILITY MODEL CONTENT

[0003] One purpose of the utility model is to provide a coal gas purification hydrogen energy system, which is applicable to Hong Kong coal gas, uses purified hydrogen for power generation, has the effect of green environmental protection, and uses the purified mixed gas for power generation and heating, thereby improving energy efficiency.

[0004] To achieve this purpose, the utility model adopts the following technical scheme:

[0005] A coal gas purification hydrogen energy system, comprising a hydrogen purification system, a heat and power cogeneration system, a fuel cell system, a first storage battery, a second storage battery, a first inverter, a second inverter and a heat exchanger unit, the inlet of the hydrogen purification system is connected to the raw material coal gas end, the hydrogen end of the hydrogen purification system is connected to the fuel cell system, the direct current end of the fuel cell system is connected to the first inverter and the first storage battery, the tail gas end of the hydrogen purification system is connected to the heat and power cogeneration system, the inlet of the heat and power cogeneration system is connected to the raw material coal gas end, the alternating current end of the heat and power cogeneration system is connected to the second inverter, the second inverter is connected to the second storage battery, and the heat source end of the heat and power cogeneration system is connected to the heat exchanger unit.

[0006] As a preferred technical scheme, gas flow meters are arranged between the inlet of the hydrogen purification system and the raw material coal gas end, between the inlet of the heat and power cogeneration system and the raw material coal gas end, between the hydrogen end of the hydrogen purification system and the fuel cell system, and between the tail gas end of the hydrogen purification system and the heat and power cogeneration system.

[0007] As a preferred technical scheme, the direct current end of the fuel cell system is connected to a direct current charging pile, and the alternating current end of the first inverter and the alternating current end of the second inverter are both connected to alternating current charging piles.

[0008] As a preferred technical scheme, the water outlet end of the heat exchanger unit is connected to a first hot water storage tank, and the backwater end of the heat exchanger unit is connected to a second hot water storage tank.

[0009] As a preferred technical scheme, temperature probes are installed on the outside of the first hot water storage tank, the outside of the second hot water storage tank, between the heat exchange unit and the combined heat and power system, between the heat exchange unit and the first hot water storage tank, and between the heat exchange unit and the second hot water storage tank.

[0010] As a preferred technical scheme, water pumps are installed between the water outlet end of the heat exchange unit and the first hot water storage tank, and between the water return end of the heat exchange unit and the combined heat and power system.

[0011] The coal gas purification hydrogen energy system is applicable to Hong Kong coal gas, has the effect of green environmental protection, improves hydrogen energy heating efficiency, and is advanced in integrated development, is matched with electric energy storage, and increases the application configuration of a standby power supply. BRIEF DESCRIPTION OF DRAWINGS

[0012] The utility model will be further described in detail below according to the drawings and examples.

[0013] Figure 1 It is the whole distribution schematic drawing of a coal gas purification hydrogen energy system of example described;

[0014] Figure 2 It is the system distribution diagram of hot water treatment part of a coal gas purification hydrogen energy system of example described;

[0015] Figure 3 It is the structure schematic diagram of desulfurization tank of hydrogen purification system of example described;

[0016] Figure 4 It is the structure schematic diagram of internal unit of a coal gas purification hydrogen energy system of example described;

[0017] Figure 5 It is the process piping and instrument diagram of metering system of hydrogen purification system of example described;

[0018] Figure 6 It is the first process piping and instrument diagram of booster system of hydrogen purification system of example described;

[0019] Figure 7 It is the second process piping and instrument diagram of booster system of hydrogen purification system of example described;

[0020] Figure 8 It is the process piping and instrument diagram of hydrogen extraction system of hydrogen purification system of example described;

[0021] Figure 9 It is the process piping and instrument diagram of venting system of hydrogen purification system of example described;

[0022] Figure 10 First structural diagram of the hydrogen purification system described in the embodiment;

[0023] Figure 11 Second structural diagram of the hydrogen purification system described in the embodiment;

[0024] Figure 12 Third structural diagram of the hydrogen purification system described in the embodiment.

[0025] Figures 1 to 12 In the figure:

[0026] 1, hydrogen purification system; 2, combined heat and power system; 3, fuel cell system; 4, first battery; 5, second battery; 6, first inverter; 7, second inverter; 8, heat exchanger unit; 9, gas flow meter; 10, direct current charging pile; 11, alternating current charging pile; 12, first hot water storage tank; 13, second hot water storage tank; 14, water pump;

[0027] 1001, skirt; 1002, first flange; 1003, cross pipe; 1004, elbow; 1005, first vertical pipe; 1006, second vertical pipe; 1007, baffle plate; 1008, head; 1009, support grid; 1010, hand hole; 1011, baffle; 1012, cylinder; 1013, floating net; 1014, second flange; 1015, gasket; 1016, stud; 1017, first nut; 1018, flat cover; 1019, distributor; 1020, third flange; 1021, first connecting pipe; 1022, lifting lug; 1023, fourth flange; 1024, second connecting pipe; 1025, flange cover; 1026, winding pad; 1027, stud; 1028, second nut; 1029, pipe cap; 1030, reinforcing rib; 1031, grounding plate;

[0028] 2001. Box components; 2002. Chassis components, random spare parts, special tools; 2003. Electrical schematics, electrical wiring diagrams, electrical logic diagrams; 2004. Air piping components, air inlet nameplate; 2005. Piping components, exhaust outlet nameplate; 2006. Cooler components; 2007. Air guide components; 2008. First separator; 2009. Explosion-proof variable frequency motor; 2010. Drain piping components, drain outlet nameplate; 2011. Coupling components; 2012. Auxiliary piping components; 2013. Oil piping components, oil drain port Signage; 2014, compressor main unit; 2015, desulfurization tank; 2016, hydrogen buffer; 2017, sewage tank; 2018, pressure swing adsorption device; 2019, explosion-proof low-pressure control cabinet; 2020, second separator; 2021, explosion-proof PLC control cabinet; 2022, vent cylinder; 2023, instrument panel components; 2024, reminder signage; 2025, packaging box components; 2026, warning signage; 2027, air supply port signage; 2028, spare air filling port signage, rivets; 2029, compressor oil, thermometer protective cover. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0030] like Figures 1 to 12 As shown, in this embodiment, a coal gas purification hydrogen energy system includes a hydrogen purification system 1, a combined heat and power system 2, a fuel cell system 3, a first battery 4, a second battery 5, a first inverter 6, a second inverter 7 and a heat exchange unit 8. The inlet of the hydrogen purification system 1 is connected to the raw coal gas end, the hydrogen end of the hydrogen purification system 1 is connected to the fuel cell system 3, the DC end of the fuel cell system 3 is connected to the first inverter 6 and the first battery 4, the tail gas end of the hydrogen purification system 1 is connected to the combined heat and power system 2, the inlet of the combined heat and power system 2 is connected to the raw coal gas end, the AC end of the combined heat and power system 2 is connected to the second inverter 7, the second inverter 7 is connected to the second battery 5, and the heat source end of the combined heat and power system 2 is connected to the heat exchange unit 8.

[0031] In the whole system, more specifically, gas flow meters 9 are arranged between the inlet of the hydrogen purification system 1 and the raw coal gas end, between the inlet of the combined heat and power system 2 and the raw coal gas end, between the hydrogen end of the hydrogen purification system 1 and the fuel cell system 3, and between the tail gas end of the hydrogen purification system 1 and the combined heat and power system 2; a direct current charging pile 10 is connected to the direct current end of the fuel cell system 3, and an alternating current charging pile 11 is connected to the alternating current end of the first inverter 6 and the alternating current end of the second inverter 7; a first hot water storage tank 12 is connected to the water outlet end of the heat exchanger set 8, and a second hot water storage tank 13 is connected to the backwater end of the heat exchanger set 8; temperature probes are installed on the outside of the first hot water storage tank 12, on the outside of the second hot water storage tank 13, between the heat exchanger set 8 and the combined heat and power system 2, between the heat exchanger set 8 and the first hot water storage tank 12, and between the heat exchanger set 8 and the second hot water storage tank 13; and water pumps 14 are installed between the water outlet end of the heat exchanger set 8 and the first hot water storage tank 12 and between the backwater end of the heat exchanger set 8 and the combined heat and power system 2.

[0032] In the Hong Kong coal gas, hydrogen is 46.3-51.8 mol%, methane is 28.2-30.7 mol%, carbon dioxide is 16.3-19.9 mol%, carbon monoxide is 1-3.1 mol%, nitrogen is 0-2.6 mol%, oxygen is 0-0.7 mol%, water is saturated and free, and tetrahydrothiophene (THT) is 17-24 mg / Sm 3 .

[0033] The hydrogen purification system 1 is used to purify hydrogen in the raw coal gas to high purity, which meets the hydrogen standard specification requirements of ISO14687; the fuel cell system 3 converts the chemical energy of hydrogen into electrical energy through a proton exchange membrane fuel cell, the combined heat and power system 2 (CHP for short) utilizes the combustion of the remaining combustible gas (tail gas for short; in the tail gas composition, hydrogen is 19.6-25.2 mol%, methane is 43.6-46.2 mol%, carbon dioxide is 24.1-27.7 mol%, carbon monoxide is 0-5.0 mol%, nitrogen is 0-4.0 mol%, and oxygen is 0-1.1 mol%) after purification to generate electricity through a generator while providing heat; the heat exchanger set 8 transfers the heat source output by the CHP to the hot water storage tank through heat exchange; and the direct current charging pile 10 and the alternating current charging pile 11 are responsible for charging new energy electric cars.

[0034] In the hydrogen purification system 1, there is a compressor, two desulfurization tanks and a pressure swing adsorption unit. The raw coal gas is boosted by the compressor and then passes through the two desulfurization tanks, so that the total sulfur (mainly THT) concentration is reduced to below 4ppb. The desulfurized coal gas enters the pressure swing adsorption unit (PSA) for hydrogen purification to obtain high-purity hydrogen. In the process, the raw coal gas is boosted from 3kPa to 970kPa by the compressor, and the tetrahydrothiophene (THT) in the coal gas is adsorbed by the activated carbon in the two desulfurization tanks. After the total sulfur concentration is reduced, the gas is separated by the pressure swing adsorption unit (PSA), which uses the difference in the adsorption performance of molecular sieves for different gas molecules to purify the hydrogen in the raw coal gas. The product gas concentration meets the ISO14687 vehicle fuel cell hydrogen fuel specification, and then two mixed gases are obtained, one is high-purity hydrogen for the fuel cell system 3 to generate electricity, and the other is tail gas for the cogeneration system 2 to generate electricity and provide hot water.

[0035] The pressure swing adsorption unit is a process for purifying gas mixtures. The process is based on the physical adsorption of gas molecules on the internal surface of porous solids (adsorbents) and is a reversible physical adsorption process that works between two pressure states. It is based on the principle that impurity components in a mixed gas have a large adsorption capacity at high pressure and a small adsorption capacity at low pressure, while the ideal component H2 has a small adsorption capacity at both high and low pressures. At high pressure, the partial pressure of impurities is increased to maximize their adsorption on the adsorbent, thereby achieving high product hydrogen purity. The desorption or regeneration of the adsorbent is carried out at low pressure to minimize the residual amount of impurities on the adsorbent for re-adsorption of impurities in the next cycle.

[0036] The fuel cell system 3 has an anode, a cathode, an electrolyte separator and an external circuit. Proton exchange membrane fuel cells (PEMFC) use an ion-conducting polymer membrane as an electrolyte, also known as polymer electrolyte fuel cells, in-body polymer fuel cells or solid polymer electrolyte fuel cells, to generate direct current.

[0037] Proton exchange membrane composition: the membrane electrode assembly is composed of a proton exchange membrane and two sides of the catalyst layer and diffusion layer. Among them, the proton exchange membrane is the core component of the fuel cell, which is a thin film with a thickness of 50-180μm, and is the substrate of the catalyst. The important feature of the proton exchange membrane is to allow only hydrogen ions to pass through, not hydrogen and electrons.

[0038] The principle of converting hydrogen energy into electric energy: the anode is the place where hydrogen fuel is oxidized, the cathode is the place where the oxidant is reduced, both electrodes contain catalysts to accelerate the electrochemical reaction of the electrode, and the proton exchange membrane serves as a medium for transferring H+ and only allows H+ to pass through. When working, it is equivalent to a direct current power supply, the anode is the negative electrode of the power supply, and the cathode is the positive electrode of the power supply; when the stack is working, hydrogen and oxygen are introduced by the inlet, distributed to the bipolar plate of each single cell through the gas main channel of the stack, and then evenly distributed to the electrode through the bipolar plate, and then contacted with the catalyst through the electrode support body to carry out electrochemical reaction.

[0039] Anode (negative electrode): 2H2→4H++4e-, Cathode (positive electrode): O2+4H++4e-→2H2O, Since the proton exchange membrane can only conduct protons, hydrogen ions (i.e. protons) can directly pass through the proton exchange membrane to the cathode, while electrons can only reach the cathode through the external circuit. When the electrons flow to the cathode through the external circuit, direct current is generated. With the anode as the reference, the cathode potential is 1.23V. That is, the theoretical upper limit of the power generation voltage of each single cell is 1.23V. When connected with a load, the output voltage depends on the output current density, usually between 0.5-1V. Multiple single cells can be stacked to form a fuel cell stack (referred to as an electric pile) that meets the actual load requirements.

[0040] The combined heat and power system 2 (CHP) is composed of a combustion chamber, a generator, a controller, a heat distributor and a control system. The exhaust gas is burned in the CHP to provide heat and generate electricity. Nearly two-thirds of the energy used in traditional power generation is wasted in the form of heat discharged into the atmosphere, and additional energy is wasted in the process of distributing electricity to end users. CHP captures and uses the heat that would otherwise be wasted, and avoids distribution losses, so that combined heat and power can achieve an efficiency of over 80%, while typical technologies (i.e. traditional power generation and on-site boilers) have an efficiency of 50%.

[0041] The first hot water storage tank 12 and the second hot water storage tank 13 are 5000L water cylinders, which are used as heat storage devices. Three temperature sensors are arranged on the water cylinders to monitor the real-time temperature inside the water cylinders at any time. The control room controls the operation of the water heater unit by monitoring whether the water temperature inside the water cylinder reaches the set temperature, and provides control instructions to the CHP system to determine whether to operate.

[0042] In the process of converting high-purity hydrogen into electric energy, high-purity hydrogen is converted into electric energy (H2 power generation) by the fuel cell system 3, and direct current is output; the direct current generated by the fuel cell system 3 is increased in voltage by the built-in transformer in the system, and is output to the storage battery for storage, or is supplied to the DC charging pile for charging the vehicle; the direct current generated by the fuel cell system 3 can also be converted into alternating current (DC->AC) by the inverter to supply the charging pile for charging the vehicle.

[0043] In the operation of the system, the charging pile is powered by the lithium battery after the system is started. The EMS system continuously monitors the SOC of the lithium battery. When the SOC of the lithium battery is less than 70%, the fuel cell power supply is automatically started. When the charging pile is in use, the fuel cell power supply can reduce the discharge of the lithium battery and prolong the power supply time. When the charging pile is not in use, the fuel cell continuously charges the lithium battery until the SOC is greater than 90% and the fuel cell operation is stopped. The above SOC related logic level needs to be adjusted according to the BMS design of the lithium battery after the lithium battery is confirmed. The system is estimated to have a net output of more than 10kW, plus BOP and energy conversion loss, and the estimated group output power is 13-15kW, and the output current is 90-110A.

[0044] The exhaust gas is combusted and generates electricity and heat by the CHP, the CHP generator outputs alternating current, which can be converted into direct current (DC) by an inverter to supply the battery for power storage, or directly output alternating current to the alternating current (AC) charging pile for charging; the CHP outputs heat through the internal heat carrier medium, and the heat carrier medium exchanges heat through the heat exchanger set 8 to convert the heat into hot water and store it in the hot water tank.

[0045] It should be noted that the above specific embodiments are only preferred embodiments of the present application and the technical principles applied, and any changes or replacements easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered within the protection scope of the present application.

Claims

1. A coal gas purification hydrogen energy system, characterized by, The application relates to a hydrogen purification system, a heat and power cogeneration system, a fuel cell system, a first storage battery, a second storage battery, a first inverter, a second inverter and a heat exchanger group, wherein the hydrogen purification system is connected with a raw coal gas end, the hydrogen end of the hydrogen purification system is connected with the fuel cell system, the direct current end of the fuel cell system is connected with the first inverter and the first storage battery, the tail gas end of the hydrogen purification system is connected with the heat and power cogeneration system, the heat and power cogeneration system is connected with the raw coal gas end, the alternating current end of the heat and power cogeneration system is connected with the second inverter, the second inverter is connected with the second storage battery, and the heat source end of the heat and power cogeneration system is connected with the heat exchanger group.

2. A coal gas purification hydrogen energy system according to claim 1, characterized in that, Gas flow meters are arranged between the hydrogen purification system and the raw coal gas end, between the heat and power cogeneration system and the raw coal gas end, between the hydrogen end of the hydrogen purification system and the fuel cell system and between the tail gas end of the hydrogen purification system and the heat and power cogeneration system.

3. A coal gas purification hydrogen energy system according to claim 1, characterized in that, The direct current end of the fuel cell system is connected with a direct current charging pile, and the alternating current end of the first inverter and the alternating current end of the second inverter are both connected with alternating current charging piles.

4. The coal gas purification hydrogen energy system according to claim 1, characterized in that, The water outlet end of the heat exchanger group is connected with a first hot water storage tank, and the backwater end of the heat exchanger group is connected with a second hot water storage tank.

5. A coal gas purification hydrogen energy system according to claim 4, wherein, Temperature probes are installed on the outside of the first hot water storage tank, on the outside of the second hot water storage tank, between the heat exchanger group and the heat and power cogeneration system, between the heat exchanger group and the first hot water storage tank and between the heat exchanger group and the second hot water storage tank.

6. A coal gas purification hydrogen energy system according to claim 4, wherein, Water pumps are installed between the water outlet end of the heat exchanger group and the first hot water storage tank and between the backwater end of the heat exchanger group and the heat and power cogeneration system.

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