A pretreatment device for a total hydrocarbon analyzer in a VOCs unit

Abstract

This utility model provides a pretreatment device for a total hydrocarbon analyzer in a VOCs unit, belonging to the field of total hydrocarbon analyzers at the inlet of VOCs units in petrochemical plants. The device includes a media pipeline, a shut-off valve, a gas-liquid separator, and a detection device. Two sampling pipelines are arranged in parallel between the media pipeline and the detection device. Each sampling pipeline is equipped with a gas-liquid separator, and both ends of the gas-liquid separator are equipped with shut-off valves. The gas-liquid separator contains color-changing silica gel. Color-changing silica gel is added to the transparent storage tank containing the filter element 5 of the negative pressure gas-liquid separator, and then the color-changing silica gel is replaced periodically. The color-changing silica gel allows maintenance personnel to promptly determine whether replacement is necessary, ensuring that the medium entering the oil and gas concentration analyzer is free of moisture, greatly reducing maintenance cycles and difficulty, thereby ensuring the stable operation of the oil and gas concentration analyzer.

Description

Technical Field

[0001] This utility model belongs to the field of total hydrocarbon analyzers at the inlet of VOCs units in petrochemical plants, and specifically relates to a pretreatment device for total hydrocarbon analyzers in VOCs units. Background Technology

[0002] The currently used VOCs oil and gas recovery unit is an environmental protection device. It is required to have a total hydrocarbon analyzer installed at the feed inlet to monitor the oil and gas concentration of the feed. This analyzer is connected to the safety instrumented system, and a malfunction will cause the unit to shut down. Under current operating conditions, the total hydrocarbon analyzer's overall lifespan is reduced due to the presence of liquid in the gaseous feed, resulting in a high failure rate, and the equipment cannot be operated during maintenance.

[0003] CN218546303U discloses a pretreatment device for a total hydrocarbon analyzer, including a settling tank connected to a sample inlet via an integrated heated cable; the settling tank is connected to a rotary cooler, which is connected to a coalescer; the coalescer is connected to the instrument via a sample flow meter; a Venturi pump is connected to the bottom of the settling tank; a collection tank is connected to the bottom of the rotary cooler; and a peristaltic pump is connected to the bottom of the collection tank. This invention removes water through settling and rotary cooler processes, which simultaneously remove a large amount of impurities. The sample then passes through a subsequent fine filter—the coalescer—resulting in a high level of sample cleanliness entering the instrument. High sample cleanliness is crucial for the stable operation of the instrument.

[0004] Currently, in accordance with national environmental protection requirements, various refineries are successively installing VOCs oil and gas recovery and treatment devices. These current VOCs devices have an oil and gas concentration analyzer installed between the reactor and the water seal tank, connected to an interlocking protection system, to ensure that the concentration of oil and gas entering the reactor does not exceed the explosion limit, thus ensuring production safety. However, the current oil and gas concentration analyzers used to monitor this concentration have the following shortcomings in practical use: Frequent blockages in the sampling pipeline of the oil and gas concentration analyzer; Cause of the problem: The inlet and outlet of the water seal tank both use DN300 thick pipelines, while the sampling point of the oil and gas concentration analyzer installed at the outlet of the water seal tank generally uses a sampling pipeline with an outer diameter of 8mm. The sampling pipeline has a significant reduction in diameter compared with the original pipeline. This process pipeline is used at normal temperature and pressure. If impurities are present, it will not affect the normal use of the process pipeline, but it is easy to block the sampling pipeline. Oil and gas concentration analyzer measuring equipment is susceptible to water vapor impact; Causes: Due to the large diameter of the process pipeline, the outlet of the water seal tank inevitably carries a large amount of water vapor, especially in winter. To ensure the safe use of the water seal tank, heat tracing is usually used to maintain the temperature, which brings even more water vapor into the outlet pipeline. The outlet pipeline may carry water vapor into the sampling pipeline and eventually into the measuring equipment, thus impacting the internal detection elements. The commonly used oil and gas concentration detection methods are FID (Flame Ionization) and PID (Photoionization Gas Detection). The FID method is complex and expensive. Encountering water vapor can easily lead to inaccurate measurement data or even flameout of the furnace. It requires cleaning the entire measuring pipeline and the heating furnace, followed by heating, preheating, drying, and ignition to burn off impurities. The maintenance cycle for the measuring equipment generally exceeds 24 hours. The PID method has a simple structure, but water vapor impact can directly damage the detection elements, resulting in high maintenance costs. The device has safety hazards and cannot be put into operation when the testing equipment malfunctions.

[0005] Causes: The high failure rate of the testing equipment is due to pipeline blockage and moisture entering the equipment. The equipment will malfunction within 1-2 days, and the long maintenance cycle will cause the device to be unable to be used normally for a long time. Utility Model Content

[0006] To overcome the problems of existing media being unobservable and malfunctions caused by liquid contamination in the measuring section of the total hydrocarbon analyzer, this invention provides a pretreatment device for the total hydrocarbon analyzer in a VOCs unit. This invention adds a small negative pressure filter between the measuring equipment and the media pipeline, and adds color-changing silica gel to the transparent storage tank containing the filter element of the negative pressure gas-liquid separator. The silica gel is then replaced periodically. The color-changing silica gel allows maintenance personnel to promptly determine when replacement is needed, ensuring that the medium entering the oil and gas concentration analyzer is free of moisture, significantly reducing maintenance cycles and difficulty, thereby ensuring the stable operation of the oil and gas concentration analyzer.

[0007] The technical solution provided by this utility model is as follows: A pretreatment device for a total hydrocarbon analyzer in a VOCs unit includes a media pipeline, a shut-off valve, a gas-liquid separator, and a detection device. Two sampling pipelines are arranged in parallel between the media pipeline and the detection device. Each sampling pipeline is equipped with a gas-liquid separator, and both ends of the gas-liquid separator are equipped with shut-off valves. The gas-liquid separator contains color-changing silica gel.

[0008] The gas-liquid separator is a small negative pressure filter.

[0009] The color-changing silica gel is filled to 1 / 2 of the transparent liquid storage tank where the gas-liquid separator filter element is located.

[0010] The color-changing silica gel is a cobalt-containing color-changing silica gel.

[0011] The cobalt-containing color-changing silica gel is originally blue when dry, and turns pink after absorbing liquid. It should be replaced when the amount of color-changing silica gel that has changed color accounts for 1 / 2 to 2 / 3 of the total amount.

[0012] The shut-off valve is a needle valve.

[0013] The sampling pipeline is a polymer sampling pipeline.

[0014] The sampling pipeline is a transparent pipeline.

[0015] The sampling pipeline is installed vertically, directly above the outlet pipeline of the water seal tank.

[0016] The beneficial effects of this utility model are as follows: This invention effectively solves the problem of frequent blockage in the sampling pipeline of the oil and gas concentration analyzer installed between the reactor and the water seal tank in the VOCs oil and gas recovery and treatment device.

[0017] This invention involves installing a small negative pressure filter between the measuring equipment and the medium pipeline, and adding color-changing silica gel to the transparent liquid storage tank where the filter element of the negative pressure gas-liquid separator is located, and then replacing the color-changing silica gel periodically.

[0018] In this invention, the negative pressure gas-liquid separator performs a partial gas-liquid separation function, while the filter's storage tank also stores color-changing silica gel. Color-changing silica gel has a strong water absorption capacity, and it has the advantage of completely changing color when its adsorption capacity reaches saturation. Since the outlet pipe of the water seal tank carries unstable moisture, the color-changing silica gel allows maintenance personnel to promptly determine whether it needs replacement, ensuring that the medium entering the oil-gas concentration analyzer is free of moisture. This significantly reduces maintenance cycles and difficulty, thereby ensuring the stable operation of the oil-gas concentration analyzer.

[0019] This invention incorporates two sets of small negative pressure filters and front and rear shut-off valves on each parallel pipeline. During operation, only one pipeline is activated at a time. If the silica gel in one pipeline needs to be replaced, simply open the two needle valves on the other pipeline and shut off the valve of the silica gel that needs replacement. This will not affect the operation of the oil and gas concentration analyzer, and thus will not impact the operation of the device.

[0020] The following will provide further explanation in conjunction with the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model.

[0022] Figure 2This is a schematic diagram of a gas-liquid separator.

[0023] In the figure, the attached reference numerals are: 1. Medium pipeline; 2. Shut-off valve; 3. Gas-liquid separator; 4. Detection equipment; 5. Filter element; 6. Transparent liquid storage tank. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0025] The accompanying drawings show various structural schematic diagrams according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged and may have been omitted for clarity. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0026] Example 1: To overcome the problems of existing media being unobservable and total hydrocarbon analyzers malfunctioning due to liquid carryover in some media, this utility model provides the following... Figure 1 and Figure 2 The invention illustrates a pretreatment device for a total hydrocarbon analyzer in a VOCs unit. This device incorporates a small negative pressure filter between the measuring equipment and the media pipeline. Color-changing silica gel is added to a transparent storage tank containing the filter element of the negative pressure gas-liquid separator, and then replaced periodically. The color-changing silica gel allows maintenance personnel to promptly determine when replacement is necessary, ensuring that the medium entering the oil and gas concentration analyzer is free of moisture. This significantly reduces maintenance cycles and difficulty, thereby guaranteeing the stable operation of the oil and gas concentration analyzer.

[0027] A pretreatment device for a total hydrocarbon analyzer in a VOCs unit includes a medium pipeline 1, a shut-off valve 2, a gas-liquid separator 3, and a detection device 4. Two sampling pipelines are arranged in parallel between the medium pipeline 1 and the detection device 4. Each sampling pipeline is equipped with a gas-liquid separator 3, and both ends of the gas-liquid separator 3 are equipped with shut-off valves 2. The gas-liquid separator 3 contains color-changing silica gel.

[0028] This invention uses a negative pressure gas-liquid separator 3 for primary filtration, and then adds color-changing silica gel into the separator 3. This allows maintenance personnel to promptly determine whether the silica gel needs to be replaced, significantly reducing maintenance cycles and simplifying maintenance. The detection device in this invention is an oil-gas concentration analyzer, but other detection instruments can also be used.

[0029] like Figure 1 As shown, this utility model installs two sets of gas-liquid separators 3 using a three-way connector in parallel, and installs front and rear shut-off valves 2 on each parallel pipeline. During use, only one pipeline is put into operation at a time. If the color-changing silica gel in one pipeline needs to be replaced, it is only necessary to open the two shut-off valves 2 of the other pipeline and shut off the shut-off valve 2 of the one where the color-changing silica gel needs to be replaced. This will not affect the operation of the oil and gas concentration analyzer, and thus will not affect the operation of the device.

[0030] This device isolates the liquid phase from entering the total hydrocarbon analyzer and ensures that maintenance of the pretreatment unit does not affect the normal operation of the total hydrocarbon analyzer.

[0031] This invention effectively solves the problem of frequent blockage in the sampling pipeline of the oil and gas concentration analyzer installed between the reactor and water seal tank in a VOCs oil and gas recovery and treatment system. It also addresses the issue of the oil and gas concentration analyzer's measuring equipment being susceptible to water vapor impact, and resolves the safety hazards inherent in the system, preventing its operation when the testing equipment malfunctions. The invention comprehensively improves the reliability, design rationality, and safety of the system, effectively eliminating the shortcomings of the oil and gas concentration analyzer in the VOCs oil and gas recovery and treatment system. It enhances the overall reliability and practicality of the oil and gas concentration analyzer, significantly reduces the equipment failure rate, and thus ensures the stable operation of the VOCs oil and gas recovery and treatment system.

[0032] Example 2: Based on Example 1, in this embodiment, preferably, the gas-liquid separator 3 is a small negative pressure filter.

[0033] Preferably, the color-changing silica gel is filled to 1 / 2 of the transparent liquid storage tank 6 where the filter element 5 of the gas-liquid separator 3 is located.

[0034] In this invention, the preferred gas-liquid separator 3 is a small vacuum negative pressure filter. Small vacuum negative pressure filters are existing, mature products that can be purchased and used directly on the market. Figure 2 As shown.

[0035] The gas-liquid separator 3 added in this invention is small in size and cannot completely guarantee that the medium is free of liquid phase. The color-changing silica gel inserted into the gas-liquid separator 3 can perform secondary filtration of the liquid phase, ensuring that the liquid phase is isolated at the front end of the total hydrocarbon analyzer's measurement section. After the color-changing silica gel changes color and deteriorates, it can be directly switched to the backup gas-liquid separator 3. The main gas-liquid separator 3 can be replaced with the color-changing silica gel, and the replacement time is extremely short, which is convenient for maintenance. This ensures the stability of the total hydrocarbon analyzer and solves the problem of malfunction caused by liquid in the medium in the measurement section of the total hydrocarbon analyzer.

[0036] This utility model's small-sized gas-liquid separator 3 ensures minimal medium loss and a very short throughput cycle, guaranteeing normal medium detection and thus ensuring the safety of the VOCs device; it also solves the problems of indication deviation and measurement delay caused by general liquid removal devices.

[0037] Preferably, the color-changing silica gel is a cobalt-containing color-changing silica gel.

[0038] Preferably, the cobalt-containing color-changing silica gel is originally blue when dry, and turns pink after absorbing liquid. It is replaced when the amount of color-changing silica gel that has changed color accounts for 1 / 2 to 2 / 3 of the total amount.

[0039] Color-changing silica gel is a mature product used in sealed containers. This device currently uses cobalt-containing color-changing silica gel, which is blue when dry and turns pink after absorbing liquid. It should be replaced when the amount of color-changing silica gel that has changed color accounts for 1 / 2 to 2 / 3 of the total amount. The color-changing silica gel is filled to 1 / 2 of the capacity of the transparent liquid storage tank 6 where the filter element 5 is located.

[0040] Preferably, the shut-off valve 2 is a needle valve.

[0041] Preferably, the sampling pipeline is a polymer sampling pipeline.

[0042] In this invention, the sampling pipeline is preferably a polymer sampling pipeline, which has the following advantages: 1. Corrosion resistance: Polymer materials (such as PFA and FEP) have excellent corrosion resistance and can resist the erosion of chemicals such as acids, alkalis and salts.

[0043] 2. High temperature resistance: PFA pipes can be used for a long time in a temperature range of -180℃ to +260℃, and FEP pipes also have high temperature resistance and are suitable for high temperature fluid transportation.

[0044] 3. UV resistance and aging resistance: FEP tubes have good UV stability and are not prone to aging with long-term exposure, making them suitable for outdoor use; PFA tubes also perform well under UV irradiation, extending their service life.

[0045] 4. Convenient processing and connection: Polymer pipes can be processed by welding, bonding and other methods, and are flexible in installation; the connection methods (such as electrofusion and flange connection) are highly reliable and have low maintenance costs.

[0046] 5. Wear resistance: FEP pipes have better wear resistance than steel pipes and are suitable for conveying fluids containing particles; PFA pipes reduce friction loss with their smooth inner walls.

[0047] 6. Low temperature performance: PFA pipes can maintain stable performance in the range of -60℃ to 40℃, making them suitable for fluid transportation in low temperature environments.

[0048] Preferably, the sampling pipeline is a transparent pipeline.

[0049] This invention adds a corrosion-resistant, transparent, and high-wall-thickness polymer sampling pipeline between the measurement section of the total hydrocarbon analyzer and the sampling pipeline 1, and adds two transparent small negative pressure gas-liquid separators. The small transparent liquid storage tank 6 of the gas-liquid separator 3 is filled with color-changing silica gel, which changes color during the absorption of the liquid phase. The liquid carrying status is determined by observing the color change of the silica gel. The two small negative pressure filters can be switched between one in use and one as a backup, ensuring that the medium can be detected at all times, thus solving the problem of the medium being unobservable.

[0050] Preferably, the sampling pipeline is installed vertically, directly above the outlet pipeline of the water seal tank.

[0051] This utility model mainly addresses three issues related to the oil and gas concentration analyzer installed between the reactor and water seal tank in a VOCs oil and gas recovery and integrated treatment device for oil refineries. It optimizes and improves these issues to address the shortcomings of the oil and gas concentration analyzer in practical applications of VOCs devices, thereby ensuring the stable operation of the oil and gas concentration analyzer and the smooth operation of the environmental protection device.

[0052] The three questions and their corresponding solutions are as follows: I. Frequent blockage in the sampling pipeline of the oil and gas concentration analyzer Frequent clogging in the sampling pipeline of the oil and gas concentration analyzer can be resolved by installing the sampling pipeline vertically, directly above the outlet pipeline of the water seal tank. Oil and gas are generally lightweight, and their vertical height is typically higher than that of impurities. Vertical installation above the pipeline minimizes the risk of impurities entering the sampling pipeline, thus reducing the likelihood of clogging.

[0053] II. Oil and gas concentration analyzer measuring equipment is susceptible to water vapor impact. The oil and gas concentration analyzer is susceptible to water vapor impact. The solution is to install a small negative pressure filter between the measuring device and the sampling pipeline, and add color-changing silica gel to the transparent liquid storage tank 6 where the filter element 5 of the negative pressure gas-liquid separator is located. Then, replace the color-changing silica gel regularly.

[0054] The negative pressure gas-liquid separator performs a partial gas-liquid separation function, and its transparent storage tank 6 also stores color-changing silica gel. Color-changing silica gel has a strong water absorption capacity, and it has the advantage of completely changing color when its adsorption capacity reaches saturation. Since the outlet pipe of the water seal tank carries unstable moisture, the color-changing silica gel allows maintenance personnel to promptly determine whether it needs to be replaced, ensuring that the medium entering the oil-gas concentration analyzer is free of moisture. This significantly reduces maintenance cycles and difficulty, thereby ensuring the stable operation of the oil-gas concentration analyzer.

[0055] Third, the device has safety hazards; it cannot be put into operation when the testing equipment malfunctions.

[0056] The device has a safety hazard; it cannot be put into operation when the testing equipment malfunctions. The solution is as follows: even after implementing the above two points, replacing the color-changing silica gel in the negative pressure gas-liquid separator will still cause the device to be unable to operate for a short period. The solution is to install two sets of small negative pressure filters using a three-way connector in parallel, and install front and rear shut-off valves 2 on each parallel pipeline. Generally, needle valves of the same diameter are used. During operation, only one pipeline is operated at a time. If the color-changing silica gel in one pipeline needs replacement, simply open the two needle valves on the other pipeline and shut off the needle valve requiring replacement. This will not affect the operation of the oil-gas concentration analyzer, thus not impacting the operation of the entire device.

[0057] In summary, this invention effectively solves the problem of frequent blockage in the sampling pipeline of the oil and gas concentration analyzer installed between the reactor and water seal tank in a VOCs oil and gas recovery and treatment system. It also addresses the issue of the oil and gas concentration analyzer's measuring equipment being susceptible to water vapor impact, and resolves the safety hazards inherent in the system, preventing its operation when the detection equipment malfunctions. The invention comprehensively improves the system's reliability, design rationality, and safety, effectively eliminating the shortcomings of the oil and gas concentration analyzer in the VOCs oil and gas recovery and treatment system. It enhances the overall reliability and practicality of the oil and gas concentration analyzer, significantly reduces the equipment failure rate, and thus ensures the stable operation of the VOCs oil and gas recovery and treatment system.

[0058] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0059] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0060] The examples above are merely illustrative of this utility model and do not constitute a limitation on the scope of protection of this utility model. All designs that are identical or similar to this utility model fall within the scope of protection of this utility model. Device structures and steps not described in detail in this utility model are prior art and will not be further described in this utility model.

Claims

1. A pretreatment device for a total hydrocarbon analyzer in a VOCs unit, characterized in that: It includes a medium pipeline (1), a shut-off valve (2), a gas-liquid separator (3), and a detection device (4). Two sampling pipelines are arranged in parallel between the medium pipeline (1) and the detection device (4). Each sampling pipeline is equipped with a gas-liquid separator (3). Both ends of the gas-liquid separator (3) are equipped with shut-off valves (2). The gas-liquid separator (3) is equipped with color-changing silica gel.

2. The pretreatment device for a total hydrocarbon analyzer in a VOCs unit according to claim 1, characterized in that: The gas-liquid separator (3) is a small negative pressure filter.

3. The pretreatment device for a total hydrocarbon analyzer in a VOCs unit according to claim 1, characterized in that: The color-changing silica gel is filled to 1 / 2 of the transparent liquid storage tank (6) where the filter element (5) of the gas-liquid separator (3) is located.

4. A pretreatment device for a total hydrocarbon analyzer in a VOCs unit according to claim 3, characterized in that: The color-changing silica gel is a cobalt-containing color-changing silica gel.

5. A pretreatment device for a total hydrocarbon analyzer in a VOCs unit according to claim 4, characterized in that: The cobalt-containing color-changing silica gel is originally blue when dry, and turns pink after absorbing liquid. It should be replaced when the amount of color-changing silica gel that has changed color accounts for 1 / 2 to 2 / 3 of the total amount.

6. A pretreatment device for a total hydrocarbon analyzer in a VOCs unit according to claim 1, characterized in that: The shut-off valve (2) is a needle valve.

7. A pretreatment device for a total hydrocarbon analyzer in a VOCs unit according to claim 1, characterized in that: The sampling pipeline is a polymer sampling pipeline.

8. A pretreatment device for a total hydrocarbon analyzer in a VOCs unit according to claim 7, characterized in that: The sampling pipeline is a transparent pipeline.

9. A pretreatment device for a total hydrocarbon analyzer in a VOCs unit according to claim 1, characterized in that: The sampling pipeline is installed vertically, directly above the outlet pipeline of the water seal tank.

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