System for hydrogen purification of exhaust gas in semiconductor industry and combined cooling, heat and power

Abstract

The application discloses a kind of for semiconductor industry tail gas hydrogen purification and cold heat electricity tri-generation integrated system, including the gas pressurizing device, multiple separation towers for purifying hydrogen and hydrogen fuel cell connected in sequence;Molecular membrane for dehumidification from tail gas and molecular sieve for separating hydrogen are equipped in separation tower, flue gas generated by hydrogen fuel cell is supplied to separation tower for heat supply for molecular sieve regeneration, and then input into absorption unit for heat supply or cold supply, multiple separation towers are alternately carried out hydrogen purification and molecular sieve regeneration;Separation tower includes dehumidification chamber and purification chamber, NaA molecular membrane for dehumidification is equipped in dehumidification chamber, and gas after dehumidification in dehumidification chamber is input into purification chamber;Several 3A molecular sieve and 4A molecular sieve for separating hydrogen are equipped in purification chamber in sequence;The system can realize hydrogen purification and effective dehumidification, and carry out cold heat electricity tri-generation and recover waste heat to realize filter material regeneration.

Description

Technical Field

[0001] This invention relates to the purification of exhaust gases in the semiconductor industry, and in particular to an integrated system for hydrogen purification and combined cooling, heating and power (CCHP) of exhaust gases in the semiconductor industry. Background Technology

[0002] In recent years, research on hydrogen purification and reuse methods in process exhaust gases from the electronics industry (mainly polysilicon and semiconductor manufacturing) has attracted industry attention. Based on literature review, existing results can be divided into two main categories according to purification level and post-purification application:

[0003] (1) Deep purification (purity not less than 5N) can be used for combustion power generation or hydrogen recovery and utilization. Such research often adopts energy-intensive purification processes such as cryogenic separation and pressure swing adsorption to obtain high-purity hydrogen, but such methods are generally costly and energy-intensive.

[0004] (2) Shallow purification: after purification, hydrogen can be used in the hydrogen cooling cycle of the power generation system, making it more universal.

[0005] Chinese invention application CN119754934A discloses a waste hydrogen power generation device for use in semiconductor manufacturing equipment. This device reduces the burden of purifying waste hydrogen and allows the hydrogen to be reused for power generation, thereby providing auxiliary power to the facility. The waste hydrogen power generation device of this invention includes: a hydrogen generation unit, such as an epitaxial growth apparatus; a purification unit that recovers waste hydrogen from the hydrogen generation unit and removes impurities other than hydrogen by contacting it with water to prepare refined hydrogen; a storage unit for storing the refined hydrogen; and a power generation unit that drives a generator by burning the refined hydrogen supplied from the storage unit with oxygen from the atmosphere.

[0006] The aforementioned device, based on the incompatibility of hydrogen and water, and the absorption characteristics of specific materials for other impurities, can achieve shallow purification of hydrogen. However, this method involves water contact during hydrogen purification, and moisture is present in subsequent processes. The device lacks specific equipment for dehumidification, thus affecting hydrogen combustion efficiency. Furthermore, the lack of selection and regeneration design for the filter material in the filter makes the device susceptible to performance deviations or even failure during application.

[0007] In summary, existing technologies for shallow purification processes in semiconductor industry exhaust gas purification suffer from reduced combustion efficiency due to moisture content. Furthermore, these technologies only consider hydrogen purification and combustion for power generation, neglecting the recovery and utilization of heat generated during combustion power generation and the regeneration of filter materials, resulting in low energy utilization. Summary of the Invention

[0008] Purpose of the invention: The purpose of this invention is to provide an integrated system for hydrogen purification and combined cooling, heating and power (CCHP) of exhaust gas in the semiconductor industry, which achieves hydrogen purification and effective dehumidification, as well as combined cooling, heating and power (CCHP) and waste heat recovery for filter material regeneration.

[0009] Technical Solution: The integrated system for hydrogen purification and combined cooling, heating and power (CCHP) of exhaust gas in the semiconductor industry, as described in this invention, includes a gas pressurization device, multiple separation towers for hydrogen purification, and a hydrogen fuel cell connected in sequence. The separation towers are equipped with molecular membranes for dehumidifying the exhaust gas and molecular sieves for separating hydrogen. The flue gas generated by the hydrogen fuel cell is supplied to the separation towers to provide heat for the regeneration of the molecular sieves before being input into an absorption chiller for heating or cooling. The multiple separation towers alternately perform hydrogen purification and molecular sieve regeneration.

[0010] Based on the above technical solution, the exhaust gas can be pressurized by a gas pressurization device to meet the pressure requirements of the filter materials, namely molecular membranes and molecular sieves. Molecular membranes installed in the separation tower effectively dehumidify the exhaust gas, while molecular sieves separate hydrogen, thus purifying it. This dehumidification and purification method is energy-saving and environmentally friendly. Furthermore, after the purified hydrogen is supplied to the fuel cell for power generation, the resulting flue gas is returned to the separation tower to provide heat for high-temperature regeneration of the molecular sieves for reuse. This process requires no external heating system. The flue gas heated by the separation tower is then input into the absorption chiller for heating or cooling, further improving energy efficiency. Multiple separation towers are installed, alternating between hydrogen purification and molecular sieve regeneration, working together to achieve uninterrupted purification and improve efficiency.

[0011] Preferably, the separation tower includes a dehumidification chamber and a purification chamber. The dehumidification chamber is equipped with a NaA molecular membrane for dehumidification, and the dehumidified gas is input into the purification chamber. The purification chamber is equipped with a number of 3A molecular sieves and 4A molecular sieves arranged in sequence for separating hydrogen.

[0012] The separation tower is equipped with an independent chamber for dehumidification before purification, which reduces the moisture in the gas passing through the molecular sieve. This improves the dehumidification effect and reduces the adsorption of moisture on the molecular sieve, thus avoiding affecting the hydrogen purification effect. The purification chamber is equipped with several 3A and 4A molecular sieves in sequence to further ensure the purity of the separated hydrogen.

[0013] Preferably, the purification chamber is equipped with a heating pipe that communicates with the flue gas from the hydrogen fuel cell.

[0014] The heating pipeline is located in the purification chamber, which allows the heat to be supplied to the molecular sieve more concentratedly, thereby improving its regeneration efficiency. This avoids the problem of heating pipelines being spread throughout the separation tower, which would result in a dispersed heat supply and reduce energy utilization.

[0015] Preferably, the heating pipe is bent.

[0016] The bends in the heating pipes can increase the heat exchange area and improve the heating efficiency of the separation tower.

[0017] Preferably, a switching valve is provided between the gas pressurization device and the hydrogen fuel cell and the separation tower, and the switching valve allows the pressurized exhaust gas and the flue gas generated by combustion to be supplied to different separation towers.

[0018] By setting a switching valve to supply tail gas and flue gas to different separation towers, hydrogen purification and molecular sieve regeneration can be carried out in different separation towers. The switching valve is linked, so when the separation towers work alternately, the tail gas and flue gas can be switched synchronously to ensure the smooth operation of the alternation.

[0019] Preferably, the dehumidification chamber is equipped with a pressure detection device, which delivers gas into the purification chamber when the internal pressure reaches a threshold.

[0020] A pressure detection device is installed in the dehumidification chamber. Gas is then introduced into the purification chamber when the pressure reaches the threshold. This ensures that the pressure is sufficient to effectively squeeze the water in the exhaust gas through the molecular membrane for dehumidification.

[0021] Preferably, activated carbon is provided in the channel connecting the dehumidification chamber and the purification chamber.

[0022] Activated carbon is placed in the channel to further dehumidify and improve the dryness of the gas entering the purification chamber.

[0023] Preferably, a tail gas buffer tank is provided before the gas pressurization device.

[0024] Setting up an exhaust gas buffer tank ensures that a sufficient amount of exhaust gas enters the gas pressurization device.

[0025] Preferably, an activated carbon oil separator and a high-pressure stabilizing tank are sequentially installed between the gas pressurization device and the separation tower.

[0026] An activated carbon oil separator can remove residual oil from the exhaust gas, and a high-pressure stabilizing pipe can ensure the stability of other pressures entering the separation tower.

[0027] Preferably, a hydrogen storage tank is connected between the plurality of separation towers and the hydrogen fuel cell, and the hydrogen storage tank is equipped with a hydrogen concentration detection device.

[0028] The hydrogen storage tank is equipped with a hydrogen concentration detection device to ensure that the purified hydrogen concentration is sufficient, thus preventing ineffective combustion or safety accidents from occurring in the fuel cell.

[0029] Beneficial effects: By setting up a molecular membrane for dehumidification in the separation tower and using a molecular sieve to separate hydrogen, hydrogen purification and dehumidification can be achieved. Moreover, the purification method is energy-saving and environmentally friendly. The purified hydrogen is used to power the fuel cell, and the flue gas generated is then fed back to the separation tower to regenerate the molecular sieve. This not only recovers waste heat but also enables the reuse of the molecular sieve. Furthermore, setting up multiple separation towers allows for alternating extraction and regeneration, enabling continuous hydrogen purification and improving work efficiency. The heated flue gas is then fed back into the absorption chiller for cooling or heating, further improving energy utilization. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the system;

[0031] Figure 2 This is a schematic diagram of the separation tower structure. Detailed Implementation

[0032] The purification of hydrogen in this invention is based on the quality requirements for fuel hydrogen in the GB / T 37244-2018 standard "Fuel Hydrogen for Proton Exchange Membrane Fuel Cell Vehicles". That is, the purity of fuel hydrogen only needs to reach 99.97%, but the content of NH3, total sulfur and total halogen compounds in the composition must be specifically required.

[0033] Based on the characteristics of the electronics factory process, the exhaust gas from the hydrogen-containing process contains organic and acidic gases. Most of the organic and acidic gases are removed by rotary adsorption and alkaline spraying. The specific process flow, typical exhaust gas treatment methods and the composition of the treated gas are shown in Table 1.

[0034] Table 1. Analysis of Semiconductor Hydrogen-Containing Process and Exhaust Gas Components

[0035]

[0036]

[0037] In addition to the components mentioned above, the exhaust gas will inevitably contain a large amount of moisture due to the spraying process involved in the exhaust gas treatment. Referring to Table 1, if all hydrogen-containing exhaust gases from the semiconductor process are collected and purified, the purified exhaust gas will consist of: H2O, O2, NH3, N2, and H2.

[0038] Based on these research results, this invention prioritizes molecular sieve separation for purification: This invention utilizes the high permeability of 3A molecular sieves (0.3 nm pore size) under high pressure to gases with molecular diameters smaller than 0.3 nm, and the heating process also allows for the release of the absorbed gas. Based on this principle, the H2 absorption logic of this invention is shown in Table 2.

[0039] Table 23A Molecular Sieves Selective Permeability Analysis Table

[0040]

[0041] Furthermore, since large molecular gases are blocked or absorbed by the 3A molecular sieve, periodic regeneration is required. A common regeneration method is thermal regeneration, with a regeneration temperature of 300°C at normal pressure and as low as 150°C at high pressure (>0.5MPa). Considering that the hydrogen proposed in this invention will be used in the power generation of hydrogen-oxygen batteries, the flue gas temperature after hydrogen fuel power generation can reach 300–500°C. Recovering the heat from this flue gas section can achieve low-energy regeneration of the molecular sieve.

[0042] Finally, because H2O is highly polar, it can be adsorbed by molecular sieves, thus reducing the selective permeation of other molecules by the molecular sieves. Therefore, it needs to be separated before other molecules. The traditional common dehumidification method is rotary dehumidification, which adsorbs moisture by filling the rotor with dehumidifiers and then regenerates it by passing it through high-temperature air at 120±10℃. The adsorption and regeneration processes alternate as the rotor rotates. Since the rotor occupies a large space, this invention provides a novel dry-wet separation layered molecular sieve separation tower for dehumidification and hydrogen purification.

[0043] As shown in the figure, the present invention provides an integrated system for hydrogen purification and combined cooling, heating and power (CCHP) of exhaust gas in the semiconductor industry, comprising a gas pressurization device 1, multiple separation towers 2 for hydrogen purification, and a hydrogen fuel cell 3 connected in sequence. The separation towers 2 are equipped with molecular membranes for dehumidifying the exhaust gas and molecular sieves for separating hydrogen. The flue gas generated by the hydrogen fuel cell 3 is supplied to the separation towers 2 to provide heat for the regeneration of the molecular sieves before being input into an absorption chiller 4 for heating or cooling. The multiple separation towers 2 alternately perform hydrogen purification and molecular sieve regeneration.

[0044] The gas booster device 1 can be a common air compressor. A tail gas buffer tank 5 can also be provided before the gas booster device 1. A primary filter device 9 can also be provided before the tail gas buffer tank 5. The primary filter device 9 can be made of synthetic fiber filter media to intercept large particulate pollutants ≥5μm. An activated carbon oil remover 6 and a high-pressure stabilizing tank 7 can be provided in sequence between the gas booster device 1 and the separation tower 2.

[0045] This embodiment sets up two separation towers 2, but more separation towers 2 can be set up according to actual needs; the high-pressure stabilizing tank 7 is connected to the two separation towers 2 through a switching valve. The switching valve enables the supply of pressurized tail gas to only one of the two separation towers 2 at the same time. The switching valve can be a solenoid valve for easy control.

[0046] The separation tower 2 includes a dehumidification chamber 2-1 and a purification chamber 2-2, which are separated by a vertical plate inside the separation tower 2. The pressurized exhaust gas is input from the dehumidification chamber 2-1. The dehumidification chamber 2-1 has a NaA molecular membrane 2-3 for dehumidification in the middle and a water outlet 2-9 at the bottom. The dehumidification chamber 2-1 is equipped with a pressure detection device 2-7. When the internal pressure reaches the threshold, dehumidification is considered complete, and gas is supplied to the purification chamber 2-2. The channel connecting the dehumidification chamber 2-1 and the purification chamber 2-2 is set on the vertical plate in the middle of the separation tower 2. Activated carbon 2-8 is placed in the channel, and electric gates 2-10 are set at both ends of the channel. When the pressure detection device 2-7 detects that the internal pressure of the dehumidification chamber 2-1 meets the standard, the two electric gates 2-10 are opened.

[0047] The purification chamber 2-2 is equipped with a 3A molecular sieve 2-4 and a 4A molecular sieve 2-5 for hydrogen separation, arranged sequentially from top to bottom. The number of the two types of molecular sieves can be set according to actual needs. The purification chamber 2-2 is equipped with a heating pipe 2-6 that communicates with the flue gas of the hydrogen fuel cell 3. The heating pipe 2-6 can be set on the side wall of the purification chamber 2-2, or it can be partially set on the side wall and partially extended into the purification chamber 2-2 to increase the heat exchange area. The heating pipe 2-6 can also be set in a bend. The gas output from the heating pipe 2-6 supplies the absorption unit 4 for heating or cooling. The absorption unit 4 can be a flue gas type water-lithium bromide absorption chiller / hot water unit.

[0048] The gas output from the purification chamber 2-2 can be first fed into the hydrogen storage tank 8 for storage, and a hydrogen concentration detection device is installed in the hydrogen storage tank 8 to ensure that the hydrogen concentration meets the standard. The hydrogen in the hydrogen storage tank 8 is then fed into the hydrogen fuel cell 3.

[0049] The flue gas output pipe of the hydrogen fuel cell 3 is connected to the heating pipes 2-6 of different separation towers 2 via a switching valve (or a solenoid valve). This switching valve is also linked to the switching valve connected to the high-pressure stabilizing tank 7 and the separation tower 2, meaning both switching valves switch direction simultaneously, allowing the flue gas and exhaust gas to be input into different separation towers 2. The separation tower inputting the exhaust gas purifies the hydrogen, while the separation tower outputting the flue gas regenerates the molecular sieve. The alternating operation of the two separation towers 2 enables continuous hydrogen purification throughout the system.

[0050] In the system described in this invention, only the air booster and the operation of the absorption chiller require a small amount of electricity, while the rest of the process consumes no energy or emits carbon. Thus, it is possible to achieve low-energy and low-carbon power supply, cooling and heating.

Claims

1. A system for the purification of hydrogen from semiconductor industry off-gas and combined heat and power, characterized by: It includes a gas pressurization device (1), multiple separation towers (2) for purifying hydrogen, and a hydrogen fuel cell (3) connected in sequence; the separation tower (2) is equipped with a molecular membrane for dehumidifying the exhaust gas and a molecular sieve for separating hydrogen. The flue gas generated by the hydrogen fuel cell (3) is supplied to the separation tower (2) for heating the molecular sieve regeneration and then input into the absorption unit (4) for heating or cooling. Multiple separation towers (2) alternately perform hydrogen purification and molecular sieve regeneration. The separation tower (2) includes a dehumidification chamber (2-1) and a purification chamber (2-2). The dehumidification chamber (2-1) is equipped with a NaA molecular membrane (2-3) for dehumidification. The dehumidified gas from the dehumidification chamber (2-1) is fed into the purification chamber (2-2). The purification chamber (2-2) is equipped with several 3A molecular sieves (2-4) and 4A molecular sieves (2-5) arranged in sequence for separating hydrogen. The purification chamber (2-2) is equipped with a heating pipe (2-6) connected to the flue gas of the hydrogen fuel cell (3). The heating pipe (2-6) is bent. The dehumidification chamber (2-1) is equipped with a pressure detection device (2-7). When the internal pressure reaches the threshold, gas is supplied to the purification chamber (2-2). Activated carbon (2-8) is provided in the channel connecting the dehumidification chamber (2-1) and the purification chamber (2-2). A switching valve is provided between the gas booster (1) and the hydrogen fuel cell (3) and the separation tower (2), which allows the boosted exhaust gas and the flue gas generated by combustion to flow to different separation towers (2) respectively; an exhaust gas buffer tank (5) is provided in front of the gas booster (1); an activated carbon oil remover (6) and a high pressure stabilizing tank (7) are provided between the gas booster (1) and the separation tower (2) in sequence.

2. The system according to claim 1, characterized in that: A hydrogen storage tank (8) is connected between the multiple separation towers (2) and the hydrogen fuel cell (3), and the hydrogen storage tank (8) is equipped with a hydrogen concentration detection device.

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