An off-gas recovery device

Abstract

The application discloses a tail gas recovery device, which comprises a pressurizing device, a gas adsorption separator, a buffer device and a purifier connected in sequence to recover and purify tail gas; the pressurizing device is used for pressurizing the tail gas into the gas adsorption separator; the gas adsorption separator is used for adsorbing water and impurities in the tail gas; the buffer device is used for storing and releasing the tail gas; and the purifier is used for purifying the tail gas.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas treatment technology, and in particular to an exhaust gas recovery device. Background Technology

[0002] Currently, the main process used in the epitaxial growth of semiconductor materials and the manufacturing of light-emitting diode chips is metal-organic chemical vapor deposition (MOCVD). The process requires high-purity NH3 and SiH4 as the specialty gases and high-purity N2 and H2 as the carrier gases. Because the specialty gases in the MOCVD system do not fully participate in the reaction, the exhaust gas contains toxic and harmful substances. Therefore, the exhaust gas must be treated, and most of it is vented into the atmosphere after production.

[0003] Existing MOCVD equipment exhaust gas recovery methods often utilize water spray absorption, membrane module circulation absorption, and sulfuric acid-base neutralization absorption. However, these methods only recover NH3 from the exhaust gas, while hydrogen in the exhaust gas is not effectively recovered, resulting in energy waste. Furthermore, hydrogen emissions pose certain safety risks and could potentially lead to major production accidents.

[0004] Therefore, how to recover hydrogen from exhaust gas is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an exhaust gas recovery device to recover hydrogen from exhaust gas.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A tail gas recovery device includes a pressurizing device, a gas adsorption separator, a buffer device and a purifier connected in sequence to recover and purify tail gas.

[0008] The pressurizing equipment is used to pressurize the exhaust gas into the gas adsorption separator, which is used to adsorb moisture and impurities in the exhaust gas. The buffer equipment is used to store and release the exhaust gas, and the purifier is used to purify the exhaust gas.

[0009] Optionally, in the above-mentioned exhaust gas recovery device, the buffer device includes a buffer tank, which is used to store exhaust gas when the buffer device is in the first state.

[0010] When the buffer device is in the second state, the buffer tank releases exhaust gas, and the purifier purifies the exhaust gas in the buffer tank.

[0011] Optionally, in the above-mentioned exhaust gas recovery device, the buffer device further includes a bypass valve, a first isolation valve, and a second isolation valve.

[0012] A buffer tank is installed on the first branch, and a first isolation valve and a second isolation valve are respectively installed on both sides of the buffer tank to control the opening and closing of the first branch; a bypass valve is installed on the second branch to control the opening and closing of the second branch.

[0013] The bypass valve and the first isolation valve are open, the second isolation valve is closed, and the buffer device is in the first state;

[0014] The second isolation valve is open, the bypass valve and the first isolation valve are closed, and the buffer device is in the second state.

[0015] Optionally, in the above-mentioned tail gas recovery device, the purifier includes a primary hydrogen purifier and a cryogenic purifier, which are arranged sequentially downstream of the buffer device.

[0016] Optionally, the exhaust gas recovery device described above also includes a gas-water separation device, which is located upstream of the gas adsorption separator to separate the gas and water in the exhaust gas.

[0017] Optionally, the exhaust gas recovery device described above may also include a filtration device to filter impurities in the exhaust gas.

[0018] Optionally, in the above-mentioned exhaust gas recovery device, the filtration equipment includes a coarse filter and a fine filter, with the coarse filter located upstream of the pressurizing equipment and the fine filter located downstream of the coarse filter and upstream of the gas adsorption separator.

[0019] Optionally, in the above-mentioned exhaust gas recovery device, the coarse filter includes a first coarse filter and a second coarse filter, wherein when one of the first coarse filter and the second coarse filter is in a working state, the other is in a non-working state; and / or,

[0020] The fine filter includes a first fine filter and a second fine filter, wherein when one of the first fine filter and the second fine filter is in a working state, the other is in a non-working state.

[0021] Optionally, the above-mentioned exhaust gas recovery device also includes a gas analysis device, which is located downstream of the purifier to detect the purity of hydrogen in the exhaust gas.

[0022] Optionally, the exhaust gas recovery device described above also includes an exhaust gas flow regulating device, which is used to control the amount of exhaust gas emitted.

[0023] The exhaust gas recovery device provided by this invention includes a pressurizing device, a gas adsorption separator, a buffer device, and a purifier connected in sequence to recover and purify exhaust gas. The exhaust gas containing hydrogen is pressurized by the pressurizing device and then enters the gas adsorption separator. The gas adsorption separator can adsorb and remove most of the moisture in the exhaust gas and adsorb impurities down to the PPM level. After being buffered by the buffer device, the purifier purifies the exhaust gas, thereby obtaining hydrogen that meets process standards, achieving the recovery of hydrogen from the exhaust gas.

[0024] In addition, the presence of the buffer device ensures the stability and continuity of gas supply to equipment located downstream of the buffer device when upstream equipment needs to be inspected or maintained.

[0025] Furthermore, the exhaust gas recovery device provided by this invention can recover and reuse hydrogen in the exhaust gas. The recovered hydrogen can be reused as fuel and process raw material. For example, when treating waste gas with regenerative catalytic combustion (RTO), hydrogen can be used instead of natural gas as fuel to treat process organic waste gas, thereby realizing the reuse of hydrogen and avoiding energy waste.

[0026] The exhaust gas recovery device provided by this invention is used to recover the exhaust gas generated by epitaxial MOCVD equipment. Because the exhaust gas of epitaxial MOCVD has few types of gases, high purity, is easy to recover, and has high recovery efficiency, it can greatly reduce the recovery and use costs. Moreover, the exhaust gas recovery device uses physical methods to recover hydrogen, without the need for auxiliary fuel and combustion reaction, which increases the overall stability and safety of the device while also reducing energy consumption. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is an overall structural diagram of the exhaust gas recovery device disclosed in an embodiment of the present invention;

[0029] Figure 2 This is a structural diagram of the exhaust gas recovery device for waste gas treatment disclosed in an embodiment of the present invention;

[0030] in:

[0031] 101 is the first coarse filter; 102 is the second coarse filter;

[0032] 200 is a pressurization device;

[0033] 300 is a gas-liquid separation device;

[0034] 401 is the first fine filter; 402 is the second fine filter;

[0035] 500 is a gas adsorption separator;

[0036] 601 is a buffer tank; 602 is a bypass valve; 603 is a first isolation valve; 604 is a second isolation valve;

[0037] 701 is a primary hydrogen purifier; 702 is a cryogenic purifier;

[0038] 800 is an exhaust gas regulation device;

[0039] 900 is a waste gas treatment device. Detailed Implementation

[0040] The following will refer to the appendices in the embodiments of the present invention. Figures 1-2 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making novel efforts are within the scope of protection of the present invention.

[0041] In the description of this invention, it should be understood that the terms "upper," "lower," "top surface," "bottom surface," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the indicated position or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] like Figure 1 As shown, the exhaust gas recovery device disclosed in this invention includes a pressurizing device 200, a gas adsorption separator 500, a buffer device, and a purifier connected in sequence to recover and purify the exhaust gas; the pressurizing device 200 is used to pressurize the exhaust gas into the gas adsorption separator 500, the gas adsorption separator 500 is used to adsorb moisture and impurities in the exhaust gas, the buffer device is used to store and release the exhaust gas, and the purifier is used to purify the exhaust gas.

[0043] The exhaust gas recovery device provided by this invention includes a pressurizing device 200, a gas adsorption separator 500, a buffer device, and a purifier connected in sequence to recover and purify exhaust gas. The exhaust gas containing hydrogen is pressurized by the pressurizing device 200 and then enters the gas adsorption separator 500. The gas adsorption separator 500 can adsorb and remove most of the moisture in the exhaust gas and adsorb impurities down to the PPM level. After buffering by the buffer device, the purifier purifies the exhaust gas, thereby obtaining hydrogen that meets process standards, thus realizing the recovery of hydrogen from the exhaust gas.

[0044] In addition, the presence of the buffer device ensures the stability and continuity of gas supply to equipment located downstream of the buffer device when upstream equipment needs to be inspected or maintained.

[0045] Furthermore, the exhaust gas recovery device provided by this invention can recover and reuse hydrogen in the exhaust gas. The recovered hydrogen can be reused as fuel and process raw material. For example, when treating waste gas with RTO, hydrogen can be used instead of natural gas as fuel to treat process organic waste gas, realizing the reuse of hydrogen and avoiding energy waste.

[0046] The exhaust gas recovery device provided by this invention is used to recover the exhaust gas generated by epitaxial MOCVD equipment. Because the exhaust gas of epitaxial MOCVD has few types of gases, high purity, is easy to recover, and has high recovery efficiency, it can greatly reduce the recovery and use costs. Moreover, the exhaust gas recovery device uses physical methods to recover hydrogen, without the need for auxiliary fuel and combustion reaction, which increases the overall stability and safety of the device while also reducing energy consumption.

[0047] To optimize the above technical solution, the buffer device includes a buffer tank 601, which is used to store exhaust gas when the buffer device is in the first state; and when the buffer device is in the second state, the buffer tank 601 releases exhaust gas, and the purifier purifies the exhaust gas in the buffer tank 601.

[0048] Buffer tank 601 serves as an intermediate container. When the buffer device is in its first state, buffer tank 601 acts as a storage device to store the exhaust gas treated by the equipment upstream of buffer tank 601. When the buffer device is in its second state, buffer tank 601 acts as a release device to release the exhaust gas stored in the first state. The existence of the buffer device ensures the stability and continuity of gas supply to the equipment downstream of the buffer device, and facilitates the inspection and maintenance of the equipment upstream of the buffer device.

[0049] Specifically, such as Figure 1As shown, the buffer device has two branches. The first isolation valve 603, the second isolation valve 604, and the buffer tank 601 are located in the first branch, with the first isolation valve 603 and the second isolation valve 604 respectively located on both sides of the buffer tank 601. The bypass valve 602 is located in the second branch. The first isolation valve 603, the second isolation valve 604, and the bypass valve 602 work together to control the switching between the first and second states of the buffer device.

[0050] The first isolation valve 603 is located upstream of the buffer tank 601. Opening the first isolation valve 603 and the bypass valve 602, and closing the second isolation valve 604, closes the first branch and opens the second branch, putting the buffer device in its first state. Part of the exhaust gas treated by the equipment upstream of the buffer tank 601 reaches the buffer tank 601 via the first isolation valve 603 and fills it completely; another part reaches the purifier via the second branch through the bypass valve 602.

[0051] The first isolation valve 603 and bypass valve 602 are closed, and the second isolation valve 604 is opened, opening the first branch and closing the second branch, placing the buffer device in the second state. Because the first isolation valve 603 is closed, the equipment upstream of the buffer tank 601 no longer supplies treated exhaust gas. The second isolation valve 604 is opened, allowing the buffer tank 601 to release the exhaust gas stored in the first state. The exhaust gas then travels through the second isolation valve 604 and the first branch to the purifier, ensuring uninterrupted operation of the purifier even when the equipment upstream of the buffer tank 601 is under maintenance or repair, thus improving efficiency.

[0052] To improve the purification level of hydrogen and reduce the impurity content, the purifier includes a primary hydrogen purifier 701 and a cryogenic purifier 702. These two purifiers are sequentially arranged downstream of the buffer unit to purify the tail gas. The primary purifier reduces impurities in the tail gas to the PPB level. The purified gas then enters the cryogenic purifier 702 for further adsorption of impurities, ultimately reducing the impurities to below 1 PPB, meeting the process hydrogen usage standards for downstream equipment. Using two different types of purifiers ensures the separation of impurities from the tail gas, obtaining high-purity, production-ready hydrogen and improving the stability of the gas supply. It should be noted that the purifier used in this invention is an adsorption-type purifier, which has lower pressure loss and lower energy consumption compared to palladium membrane purifiers.

[0053] If the exhaust gas contains a large number of impurities, these impurities will cause wear and damage to various parts of the exhaust gas recovery device. To reduce the amount of impurities entering downstream equipment and extend the service life of the exhaust gas recovery device, a filtration system is installed to remove impurities from the exhaust gas.

[0054] Specifically, due to different filtration precision, the filtration equipment includes coarse filters and fine filters. Coarse filters remove large particulate matter from the exhaust gas. Coarse filters use physical adsorption to perform preliminary purification of the exhaust gas, removing non-polar or weakly polar impurities that are insoluble in water. Fine filters, building upon the coarse filters, remove small particulate impurities from the exhaust gas. Fine filters use chemical adsorption to perform fine purification of the exhaust gas, removing polar impurities that are soluble in water. To prevent impurities from damaging the pressurizing equipment 200 and the gas adsorption separator 500, the coarse filter is installed upstream of the pressurizing equipment 200, and the fine filter is installed downstream of the coarse filter and upstream of the gas adsorption separator 500.

[0055] Because the filter elements need to be replaced promptly, to ensure the continuous operation of the exhaust gas recovery device, two coarse filters are used: a first coarse filter 101 and a second coarse filter 102, each connected to the exhaust gas treatment process. When one of the first coarse filter 101 or the second coarse filter 102 is in operation, the other is not. This one-for-one backup configuration allows for maintenance or replacement of the other filter element while one is operating normally. Similarly, the fine filters can be configured as a first fine filter 401 and a second fine filter 402, achieving a one-for-one backup configuration.

[0056] In one embodiment of the present invention, a gas-water separation device 300 can be provided upstream of the gas adsorption separator 500 to separate the gas and water in the tail gas. The separation of gas and water reduces the operating load of the adsorbent during the gas purification process and increases the service life of the adsorbent in the purifier.

[0057] Gas adsorption separation methods typically employ either temperature swing adsorption (TSA) or pressure swing adsorption (PSA) cyclic processes. This invention utilizes a pressure swing adsorber (PSA). PSA produces high-purity products and generally operates at room temperature and relatively low pressure. Bed regeneration does not require heating, reducing energy consumption. Furthermore, PSA equipment is simple to operate and maintain, enabling continuous cyclic operation and full automation. During PSA, most moisture and remaining impurities not removed in the filtration stage are removed from the gas, adsorbing impurities down to the PPM level.

[0058] In such Figure 1 The tail gas recovery device shown can be equipped with a gas analysis device at its end to detect the purity of hydrogen in the gas purified by the purifier. If the hydrogen meets the process standards, it can be collected or used directly. If the hydrogen does not meet the process standards, it indicates a problem in the upstream tail gas treatment process, and the equipment needs to be inspected and repaired.

[0059] like Figure 2As shown, the exhaust gas recovery device provided by this invention can be used in RTO (Regenerative Thermal Oxidizer) processes. Currently, with the increasing industrialization of semiconductor manufacturing enterprises, environmental policies are imposing stricter controls on the emission of organic pollutants. Therefore, the zeolite rotor + RTO process has been introduced into semiconductor manufacturing enterprises. In the process flow, VOCs waste gas is effectively adsorbed into the zeolite after passing through the zeolite concentrator rotor, achieving the purpose of removal. The volatile organic gases adsorbed by the zeolite are purified and directly discharged into the atmosphere through a chimney. The adsorbed volatile organic compounds are then transferred to the desorption zone, where a small stream of heated gas is used to desorb the volatile organic compounds. After desorption, the zeolite rotor rotates back to the adsorption zone to continuously adsorb volatile organic gases. The concentrated organic waste gas after desorption is sent to an incinerator for combustion, converting it into carbon dioxide and water vapor before being discharged into the atmosphere. In this process, natural gas can be used as fuel, but natural gas needs to be purchased externally, and the costs of pipeline construction and natural gas purchase are high. Therefore, in this invention, hydrogen that has not been effectively treated in the exhaust gas of such industry production processes can be recovered and reused as fuel, avoiding energy waste. An exhaust gas treatment device 900 is installed after the buffer equipment, using hydrogen instead of natural gas as fuel to treat the exhaust gas.

[0060] In one embodiment of the present invention, a tail gas regulating device 800 is provided upstream of the waste gas treatment equipment 900 to regulate the amount of hydrogen required by the waste gas treatment equipment 900. The tail gas regulating device 800 can be located upstream of the pressurization equipment 200, allowing for a reduction in the grade and specifications of downstream equipment and pipelines, significantly reducing construction costs. Alternatively, the tail gas regulating device 800 can be located between the buffer equipment and the waste gas treatment equipment 900, allowing gas to enter the waste gas treatment equipment 900 according to demand.

[0061] It should be noted that the exhaust gas recovery device provided by this invention can be used in the field of exhaust gas treatment technology or other fields. Other fields refer to any field other than the field of exhaust gas treatment technology. The above are merely examples and do not limit the application areas of the exhaust gas recovery device provided by this invention.

[0062] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0063] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0064] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An off-gas recovery apparatus characterized by comprising: The tail gas is recovered and purified by a pressurizing device, a gas adsorption separator, a buffer device and a purifier connected in sequence. The pressurizing device is used to press the tail gas into the gas adsorption separator, the gas adsorption separator is used to adsorb the moisture and impurities in the tail gas, the buffer device is used to store and release the tail gas, and the purifier is used to purify the tail gas. The buffer device includes a buffer tank, which is used to store the tail gas when the buffer device is in a first state. When the buffer device is in a second state, the buffer tank releases the tail gas, and the purifier purifies the tail gas in the buffer tank. The buffer device further includes a bypass valve, a first shutoff valve and a second shutoff valve, The buffer tank is arranged in a first branch, and the first shutoff valve and the second shutoff valve are arranged on both sides of the buffer tank to control the opening and closing of the first branch; the bypass valve is arranged in a second branch to control the opening and closing of the second branch. When the bypass valve and the first shutoff valve are opened and the second shutoff valve is closed, the buffer device is in the first state, and the tail gas treated by the devices upstream of the buffer tank is partially filled into the buffer tank through the first shutoff valve and partially reaches the purifier through the second branch via the bypass valve. When the second shutoff valve is opened and the bypass valve and the first shutoff valve are closed, the buffer device is in the second state, and the buffer tank releases the tail gas stored in the first state, which reaches the purifier through the first branch via the second shutoff valve, so that the purifier can work continuously when the devices upstream of the buffer tank are being repaired or maintained. The filter device is further included to filter the impurities in the tail gas, and the filter device includes a coarse filter and a fine filter, the coarse filter is arranged upstream of the pressurizing device, and the fine filter is arranged downstream of the coarse filter and upstream of the gas adsorption separator; the coarse filter includes a first coarse filter and a second coarse filter, one of which is in a working state and the other is in a non-working state. The fine filter includes a first fine filter and a second fine filter, one of which is in a working state and the other is in a non-working state.

2. The exhaust gas recovery device of claim 1, wherein The purifier includes a primary hydrogen purifier and a cryogenic purifier, which are arranged in sequence downstream of the buffer device.

3. The exhaust gas recovery device of claim 1, wherein The gas-water separation device is further included and arranged upstream of the gas adsorption separator to separate the gas and moisture in the tail gas.

4. The tail gas recovery unit of claim 1, wherein The gas analysis device is further included and arranged downstream of the purifier to detect the purity of hydrogen in the tail gas.

5. An exhaust gas recovery device according to any one of claims 1 to 4, characterized in that The tail gas flow adjusting device is further included to control the discharge amount of the tail gas.

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