Method for purging and replacing a gas installation and device for purging and replacing a gas installation

Abstract

The application relates to the technical field of coal gas purging, and provides a purging replacement method of a coal gas equipment and a purging replacement device of the coal gas equipment. The purging replacement method comprises the following steps: closing an upper gate valve between a coal gas pipeline and a coal gas drainer body; inserting a blind plate at a flange below the upper gate valve, and adding a gasket on a non-gas source side of the blind plate; opening a drainer blowdown valve at a lower end of the coal gas drainer body; keeping the drainer blowdown valve in an open state, and simultaneously opening an air inlet hole; utilizing a height difference of a downcomer communicated between the coal gas pipeline and the coal gas drainer body to make air enter from the drainer blowdown valve and the air inlet hole, and make the air discharge from a high-position exhaust port; after purging for a preset time, sampling detection is carried out to confirm that the purging replacement is qualified; the drainer blowdown valve and the air inlet hole are closed, the blind plate and the gasket are removed, and the upper gate valve is opened to a working state. The application solves the problems of strong dependence on field conditions, long preparation period, inflexible operation, high cost and the like in the prior art.

Description

Technical Field

[0001] This application relates to the field of gas purging technology, and more specifically, to a purging and replacement method and a purging and replacement device for a gas equipment. Background Technology

[0002] Currently, in industries such as metallurgy and chemicals, the maintenance of gas drainers and associated gas pipelines is a necessary step to ensure production safety. Before replacing the downcomer of a gas drainer or performing hot work on related equipment, the residual gas in the pipelines and equipment must be thoroughly purged and replaced to eliminate safety hazards such as poisoning and explosion. Existing gas purging and replacement technologies mostly employ water injection or nitrogen purging. Water injection involves injecting water into the pipeline and then draining it, using water to replace residual gas; nitrogen purging involves using an external nitrogen source to introduce inert gas into the pipeline to carry away the gas. Although these methods are widely used in actual production, they have significant drawbacks. Regarding gas source dependence, existing technologies heavily rely on fixed on-site water or nitrogen sources. Most gas operation sites are located in remote areas or have complex operating conditions, lacking stable and nearby water or gas sources, making purging and replacement impossible to implement normally. In terms of operational efficiency, the preparation process, including temporary hose laying, pipeline connection, and valve debugging, is cumbersome, significantly extending the preparation time before hot work and affecting maintenance progress. Regarding operational flexibility, external hoses, connectors, valves, and other devices are easily limited by confined space, remote locations, and difficult pipeline layout, making rapid deployment and adjustment challenging. In terms of economy, gas replacement requires continuous nitrogen consumption, and water replacement requires supporting water supply and drainage facilities; frequent and long-term operations result in high material consumption and labor costs. Furthermore, existing technologies often struggle to effectively purge blind areas between valves and pipelines, easily creating replacement dead zones where residual gas cannot be completely removed, posing safety hazards for subsequent hot work operations. Summary of the Invention

[0003] This application aims to at least address the technical problems of traditional gas purging technology, such as its strong dependence on site conditions, long preparation cycle, inflexible operation, and high cost.

[0004] To solve the above-mentioned technical problems, this application provides the following: Firstly, this application provides a purging and replacement method for a gas equipment, comprising the following steps: S1, closing the upper gate valve between the gas pipeline and the gas drainer body to cut off the gas supply channel; S2, inserting a blind flange at the flange below the upper gate valve and adding a pad on the non-gas source side of the blind flange to form a venting gap between the blind flange and the flange, the venting gap serving as a high-level exhaust port; S3, opening the drainer drain valve at the lower end of the gas drainer body to discharge the sewage from each chamber of the gas drainer body; S4, keeping the drainer drain valve in the open state, making it a low-level exhaust port. S5. Open the air inlet and simultaneously open the air inlet hole on one side of the lower end of the gas drainer body as an auxiliary air inlet; S6. Utilize the height difference of the downcomer connecting the gas pipeline and the gas drainer body to allow air to enter from the drainer's drain valve and air inlet hole, flow sequentially through the gas drainer body, lower gate valve and downcomer pipe, and exit from the high-level exhaust port; S7. After the preset purging time, sample and test the exhaust gas through the test head set on the side wall of the downcomer pipe. When the carbon monoxide concentration is lower than the preset concentration, the purging and replacement are confirmed to be qualified; S8. Close the drainer's drain valve and air inlet hole, remove the blind plate and pad, and open the upper gate valve to the working state.

[0005] This application provides a method for purging and replacing gas equipment. By cutting off the gas source, forming a high-level exhaust port with a blind flange and pads, using a drain valve as a low-level air inlet, and relying on the height difference of the downcomer to create a chimney effect, a self-driven purging and replacement method without external gas source dependence, power consumption, or medium consumption is achieved. This method effectively solves the problems of existing technologies, such as strong dependence on site conditions, long preparation cycle, inflexible operation, and high cost, and improves the safety, economy, and operability of gas facility maintenance operations.

[0006] Secondly, this application proposes a purging and replacement device for a gas equipment, used in the purging and replacement method for the gas equipment described in the above-mentioned technical solution. The purging and replacement device for the gas equipment includes: a gas pipeline for transporting gas; an upper gate valve located below the gas pipeline for cutting off the gas supply channel; a blind flange detachably inserted into the flange below the upper gate valve, with a pad on the non-gas source side of the blind flange to form a ventilation gap between the blind flange and the flange, the ventilation gap serving as a high-level exhaust port; a downcomer pipe connected at its upper end to the upper gate valve and extending downwards at its lower end; and a test head. A sampling and testing device is located on the side wall at the bottom of the downcomer. A lower gate valve is located at and connected to the lower end of the downcomer to control the flow of gas into the drainer. The gas drainer body is connected to the lower gate valve. The gas drainer body has multiple chambers arranged sequentially adjacent to each other. The upper ends of each chamber converge into the main pipeline and then connect to the lower gate valve. Multiple drainer drain valves are located at the lower ends of each chamber of the gas drainer body as low-level air inlets. An air inlet is located on one side of the lower end of the gas drainer body as an auxiliary air inlet.

[0007] The purging and replacement device for gas equipment provided in this application has all the beneficial effects of the purging and replacement method for gas equipment described above, and will not be elaborated further here.

[0008] Additional aspects and advantages of this application will become apparent in the following description or may be learned by practice of this application. Attached Figure Description

[0009] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is one of the structural schematic diagrams of a purging and replacement device for a gas equipment according to an embodiment of this application; Figure 2 This is a second schematic diagram of the purging and replacement device of a gas equipment according to an embodiment of this application; Figure 3 for Figure 1 One of the schematic diagrams of the blind flange in the purging and replacement device of the gas equipment shown in the embodiment; Figure 4 for Figure 1 A second schematic diagram of the blind flange structure in the purging and replacement device of the gas equipment shown in the embodiment; Figure 5 This is a flowchart of a purging and replacement method for a gasification equipment according to an embodiment of this application.

[0010] in, Figures 1 to 4 The correspondence between the reference numerals and component names in the attached drawings is as follows: 100 Gas equipment purging and replacement device, 1 gas pipeline, 2 upper gate valve, 3 blind flange, 31 pad, 4 downcomer, 5 test head, 6 lower gate valve, 7 drainer exhaust valve, 8 gas drainer body, 9 drainer drain valve, 10 air inlet, 11 exhaust valve. Detailed Implementation

[0011] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0012] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0013] The following reference Figures 1 to 5This application describes a purging and replacement method and a purging and replacement device for a gas equipment according to some embodiments of the present application.

[0014] According to the first aspect of this application, Figure 1 and Figure 5 As shown, one embodiment of this application provides a purging and replacement method for a gas equipment, comprising the following steps: closing the upper gate valve between the gas pipeline and the gas drainer body to cut off the gas supply channel; inserting a blind flange at the flange below the upper gate valve and adding a pad on the non-gas source side of the blind flange to form a ventilation gap between the blind flange and the flange, the ventilation gap serving as a high-level exhaust port; opening the drainer drain valve at the lower end of the gas drainer body to discharge the sewage in each chamber of the gas drainer body; keeping the drainer drain valve in the open state, making it a low-level air inlet, and simultaneously opening the gas drainer valve. The air inlet on one side of the lower end of the gas drainer body serves as an auxiliary air inlet. Utilizing the height difference of the downcomer connecting the gas pipeline and the gas drainer body, air enters from the drainer's drain valve and the air inlet, flows sequentially through the gas drainer body, the lower gate valve, and the downcomer, and exits from the high-level exhaust port. After a preset purging time, the exhaust gas is sampled and tested using a test head installed on the side wall of the downcomer. When the carbon monoxide concentration is lower than the preset concentration, the purging and replacement are confirmed to be qualified. The drainer's drain valve and air inlet are closed, the blind flange and gasket are removed, and the upper gate valve is opened to the working state.

[0015] Specifically, such as Figure 1 As shown, the purging and replacement device for the gas equipment includes a gas pipeline, an upper gate valve, a blind flange, a downcomer, a test head, a lower gate valve, a drain valve, a gas drain body, multiple drain valves, and an air inlet. The gas pipeline is used to transport gas. The upper gate valve is located below the gas pipeline to cut off the gas supply channel. The blind flange can be detachably inserted into the flange below the upper gate valve. The non-gas source side of the blind flange is equipped with a pad to create a ventilation gap between the blind flange and the flange. The ventilation gap serves as a high-level exhaust port for venting. The upper end of the downcomer is connected to the upper gate valve, and the lower end extends downward. The test head is located on the side wall at the bottom of the downcomer for sampling and testing. The lower gate valve is located at the lower end of the downcomer and is connected to the lower end of the downcomer to control the gas entering the drainer. The gas drainer body is connected to the lower gate valve. The gas drainer body has multiple chambers arranged sequentially and adjacently inside. The upper ends of each chamber converge into the main pipeline and are connected to the lower gate valve. Multiple drainer drain valves are located at the lower ends of each chamber of the gas drainer body as low-level air inlets for air intake. An air inlet is located on one side of the lower end of the gas drainer body as an auxiliary air inlet for air intake.

[0016] like Figure 5 As shown in the embodiments of this application, the purging and replacement method for gas equipment includes the following steps: S1. Close the upper gate valve between the gas pipeline and the gas drainer body to cut off the gas supply channel; S2. Install a blind flange at the flange below the upper gate valve and add a gasket on the non-air source side of the blind flange to form a venting gap between the blind flange and the flange. The venting gap serves as a high-level exhaust port. S3. Open the drain valve at the bottom of the gas drainer body to drain the sewage from each chamber of the gas drainer body. S4. Keep the drain valve of the drainer in the open position so that it serves as a low-level air inlet, and at the same time open the air inlet hole on one side of the lower end of the gas drainer body as an auxiliary air inlet. S5. Utilizing the height difference of the downcomer connecting the gas pipeline and the gas drainer body, air enters from the drainer's drain valve and air inlet, flows through the gas drainer body, the lower gate valve and the downcomer in sequence, and is discharged from the high-level exhaust port. S6. After the preset purging time, the exhaust gas is sampled and tested through the test head set on the side wall of the downcomer. When the carbon monoxide concentration is lower than the preset concentration, the purging and replacement are confirmed to be qualified. S7. Close the drain valve and air inlet of the drainer, remove the blind plate and gasket, and open the upper gate valve to the working state.

[0017] Specifically, such as Figure 5As shown, in step S1, the upper gate valve between the gas pipeline and the gas drainer body is closed to physically cut off the gas supply channel from the pipeline to the drainer and downcomer. In step S2, a blind flange is inserted at the flange below the upper gate valve, and a gasket is added to the non-gas source side of the blind flange to create a ventilation gap between the blind flange and the flange. This gap serves as a high-level exhaust port and is a key structure for achieving the chimney effect. In step S3, the drainer drain valve at the lower end of the gas drainer body is opened to drain the wastewater from each chamber. This step removes accumulated water from the chambers, making room for air to enter; furthermore, after drainage, the interior of the chambers is connected to the atmosphere, providing initial air intake conditions for establishing natural convection. In step S4, the drainer drain valve is kept open, serving as a low-level air intake, while the air inlet on one side of the lower end of the gas drainer body is opened as an auxiliary air intake. The multiple low-level air intakes increase the air intake cross-sectional area, ensuring sufficient air enters the system and providing a continuous airflow source for the chimney effect. In step S5, utilizing the height difference of the downcomer connecting the gas pipeline and the gas drainer body, air naturally enters from the drainer's drain valve and air inlet, flowing sequentially through the gas drainer body, the lower gate valve, and the downcomer, finally exiting from the high-level exhaust port. During this process, the air is driven upward by heating or density differences, forming a chimney effect, continuously carrying out residual gas from the pipeline and equipment, achieving purging and replacement without power or media consumption. In step S6, after a preset purging time, the discharged gas is sampled and tested using a test head installed on the side wall of the downcomer. When the carbon monoxide concentration is lower than a preset concentration, such as 24 ppm, the purging and replacement is confirmed to be qualified. This step ensures that residual gas has been completely removed through quantitative detection, providing safety assurance for subsequent hot work or equipment maintenance. In step S7, the drainer's drain valve and air inlet are closed, the blind flange and gasket are removed, and the upper gate valve is opened to the working state. This step completes the final stage of the purging operation, restoring the system to normal operation. The removed blind flanges and pads can be reused, reducing operating costs.

[0018] Thus, the purging and replacement method for gas equipment provided by the present application realizes self-driven purging and replacement without relying on external gas sources by cutting off the gas source, constructing a high-position exhaust port, and forming a natural convection channel using the structure of the equipment itself. Specifically, in this method, first, the upper stop valve between the gas pipeline and the gas drainer is closed to cut off the gas supply channel. Subsequently, a blind plate is inserted at the flange below the stop valve, and a cushion block is installed on the non-gas-source side of the blind plate to form a ventilation gap between the blind plate and the flange. This ventilation gap serves as the high-position exhaust port. This structural modification is simple and easy to implement, without requiring hot work cutting of the original pipeline or adding complex devices. In the scenario of natural purging using the chimney effect, in this method, the drainer blowdown valve at the lower end of the gas drainer is opened, and after draining the accumulated water in each chamber, it is kept open as the low-position air inlet. At the same time, the air inlet hole on one side at the lower end of the gas drainer is opened as an auxiliary air inlet. Utilizing the height difference of the downcomer between the gas pipeline and the gas drainer, air naturally enters from the low-position air inlet, sequentially flows through the gas drainer body, the lower stop valve, and the downcomer, and finally discharges from the high-position exhaust port. During this natural convection process, the air continuously flows upward, taking out the residual gas in the pipeline and equipment, and realizing purging and replacement without power and without medium consumption. In the scenario of residual gas removal and safety detection, in this method, the discharged gas is sampled and detected through the test head provided on the side wall of the downcomer. When the carbon monoxide concentration is lower than 24 ppm, it is confirmed that the purging and replacement is qualified. After passing the detection, the drainer blowdown valve and the air inlet hole are closed, the blind plate and the cushion block are removed, and the upper stop valve is opened to restore to the working state. The entire purging process does not require external water sources, gas sources, or power devices, and completely relies on the chimney effect formed by the structure of the equipment itself, fundamentally solving the purging problem under the condition of no public medium on site. Moreover, this method fully considers the multi-chamber structure characteristics of the gas drainer, opens the drainer blowdown valves of all chambers, and allows air to enter in parallel from each chamber to ensure that the residual gas in each chamber can be thoroughly purged. At the same time, the thickness of the cushion block can adjust the size of the ventilation gap, thereby controlling the air flow rate; the height of the downcomer, as the core parameter of the chimney effect, ensures that a sufficient pressure difference is formed between the high-position exhaust port and the low-position air inlet to drive the air flow.

[0019] Compared with existing technologies, the purging and replacement method for gas equipment provided in this application has the following advantages: First, this method does not require any external media such as water or nitrogen. Even if the work site is located in a remote area or without supporting public utilities, purging operations can still be carried out normally, fundamentally solving the problems of strong dependence on site conditions and poor versatility of existing technologies. Second, this method only requires three core operations to start purging: closing the upper gate valve, inserting a blind flange with a pad, and opening the drain valve. There is no need to lay temporary pipelines or coordinate external media, significantly shortening the preparation time before hot work or maintenance. Third, this method utilizes the height difference between the gas pipeline and the downcomer to create a chimney effect. Air continuously enters from the low-level drain valve, flows upward along the downcomer, and exits from the gap in the high-level blind flange, forming a unidirectional airflow channel throughout the entire system. This natural convection method can completely remove residual gas from the downcomer, the chambers of the drainer, and the connecting pipelines, eliminating replacement dead zones. Fourth, this method uses natural air as the replacement medium and relies on the chimney effect to achieve self-driven purging. It does not consume any nitrogen, water or other materials, and does not use power equipment such as fans or pumps, which can significantly reduce material consumption, energy consumption and labor input.

[0020] In some embodiments, optionally, such as Figure 2 As shown, the high-level exhaust port is a gas outlet valve, which is located at the bottom of the upper gate valve or the top of the downcomer pipe. When the gas equipment needs to be purged, the gas outlet valve is opened as a high-level exhaust port; when the gas equipment has been purged, the gas outlet valve is closed.

[0021] Specifically, such as Figure 2 As shown, as an alternative to the blind flange with shims solution, a specially designed exhaust valve can be used for the high-level exhaust port. This exhaust valve is installed at the bottom of the upper gate valve or the top of the downcomer pipe. It remains closed during normal operation of the gas equipment to ensure the gas system's sealing. When purging and replacement operations are required, the exhaust valve is opened, making it a high-level exhaust port using the chimney effect. This design shares the same technical principle as the blind flange with shims solution, both providing a high-level gas outlet through the chimney effect. However, the operation differs. The exhaust valve can be quickly opened and closed by rotating the valve handle or through remote control, eliminating the need for mechanical operations such as inserting blind flanges or adding shims. This is particularly suitable for stationary gas facilities requiring frequent purging operations. Compared to existing technologies, this solution not only achieves natural convection purging without external gas source dependence but also further improves operational convenience and system sealing reliability, providing a flexible option for different application scenarios.

[0022] In some embodiments, optionally, such as Figure 1 and Figure 2As shown, there are multiple low-level air inlets, including multiple drain valves installed at the lower end of the gas drainer body; when the gas equipment is purged, multiple low-level air inlets are opened simultaneously, air enters in parallel, and is discharged upward after flowing into the downcomer pipe.

[0023] Specifically, such as Figure 1 As shown, multiple low-level air inlets are configured, specifically including multiple drain valves located at the lower end of the gas drainer body. In practical applications, the gas drainer body is typically divided into multiple sequentially adjacent chambers, each with an independent drain valve at its lower end. During purging operations, the drain valves of all chambers are opened simultaneously, allowing air to enter in parallel from multiple low-level air inlets. The advantages of this multi-channel parallel air intake method are twofold: firstly, the simultaneous operation of multiple air inlets significantly increases the total air intake cross-sectional area, reduces air intake resistance, and allows more air to quickly enter the system, providing a sufficient airflow source for the chimney effect; secondly, each chamber's drain valve corresponds to its respective chamber, and air enters directly from the bottom of each chamber, ensuring that residual gas in each chamber is effectively purged, avoiding the problem of incomplete purging of distant chambers due to a single air inlet. The airflow from multiple low-level air inlets merges in the main pipeline that flows into the downcomer after passing through their respective chambers. They then flow upward together and are discharged from the high-level exhaust port, forming parallel air intake and series exhaust, which significantly improves purging efficiency and uniformity.

[0024] In some embodiments, optionally, such as Figure 1 and Figure 2 As shown, the gas drainer body has multiple chambers arranged sequentially and adjacently inside. Each chamber has a drainer drain valve at its lower end. The upper ends of the multiple chambers converge into the main pipeline and are connected to the lower gate valve. When the gas equipment is purged, the drainer drain valves of all chambers are opened, allowing air to enter from each chamber in parallel.

[0025] Specifically, such as Figure 1As shown, the gas drainer body has multiple sequentially adjacent chambers. Each chamber has an independent drain valve at its lower end, while the upper ends of all chambers converge into the same main pipeline and connect to the lower gate valve. This multi-chamber structure collects condensate and acts as a water seal during operation. When using the method of this application for purging and replacement, the drain valves of all chambers are opened simultaneously, allowing air to enter in parallel from the bottom of each chamber. Air enters independently from the drain valve of each chamber, flowing through its own chamber and driving the residual gas upwards. After reaching the top of each chamber, the airflow converges into the common main pipeline, merges, and then enters the downcomer through the lower gate valve, finally exiting from the high-level exhaust port. This parallel intake and series exhaust method not only significantly increases the total intake cross-sectional area but, more importantly, ensures that the residual gas in each independent chamber can be directly and effectively purged, completely eliminating any potential dead zones caused by chamber separation and significantly improving the comprehensiveness and uniformity of the purging.

[0026] In some embodiments, optionally, such as Figure 3 and Figure 4 As shown, in step S2, the thickness of the pad is set to 5mm~10mm to adjust the ventilation gap and control the gas flow rate.

[0027] Specifically, such as Figure 1 and Figure 3 As shown, the thickness of the gasket directly determines the size of the vent gap between the blind flange and the flange. A thicker gasket results in a larger vent gap, lower gas flow resistance, and a corresponding decrease in airflow velocity but an increase in flow rate. Conversely, a thinner gasket results in a smaller vent gap, increasing airflow velocity but limiting flow rate. A gasket thickness of 5mm to 10mm allows the vent gap to remain within a reasonable range of 1mm to 5mm. Within this range, the cross-sectional area of ​​the high-level exhaust port matches the diameter of the downcomer, ensuring sufficient exhaust flow to meet purging requirements while maintaining an appropriate airflow velocity to create a stable chimney effect. If the gasket thickness is too small, the vent gap will be too small, leading to excessive airflow resistance and potentially insufficient air intake, prolonging purging time. Conversely, if the gasket thickness is too large, the vent gap will be too large. Although the air intake will increase, the pressure drop at the high-level exhaust port will decrease, potentially weakening the chimney effect and reducing purging efficiency.

[0028] In specific applications, the thickness of the pad can be set to 5mm, 8mm or 10mm, depending on the actual use situation, and will not be listed here.

[0029] In some embodiments, optionally, such as Figure 5 As shown, in step S3, the time for draining the accumulated water is 3 to 10 minutes, until the water in each chamber is completely drained.

[0030] Specifically, such as Figure 1 and Figure 5 As shown, in step S3, the drainage time is set to 3-10 minutes until all water in each chamber is completely emptied. This design is based on the volume of the gas drainer body, the diameter of the drainer's drain valve, and the characteristics of gravity drainage. In actual operation, after opening the drain valve, the water in each chamber flows out naturally under gravity. The drainage time depends on the chamber volume and water depth; a smaller volume or shallower water results in a shorter drainage time, while a larger volume or deeper water results in a longer drainage time. Setting a drainage time range of 3-10 minutes ensures that operators have sufficient time to completely empty all water from each chamber, regardless of the drainer's specifications. If water remains in the chamber, it will obstruct the gas flow path, preventing air from entering the system from the low-level air inlet. Simultaneously, the water may be carried by the airflow into the downcomer or even the high-level exhaust port, affecting the purging effect and potentially causing secondary pollution.

[0031] In specific applications, the drainage time can be set to 3 minutes, 5 minutes, 8 minutes, or 10 minutes, depending on the actual usage situation. These options will not be listed here.

[0032] In some embodiments, optionally, such as Figure 5 As shown, in step S5, the height of the downcomer is 5m to 20m to ensure that a sufficient pressure difference is formed between the high-level exhaust port and the low-level air intake port to drive airflow.

[0033] Specifically, such as Figure 1 and Figure 5 As shown, the height of the downcomer directly determines the vertical drop between the high-level exhaust port and the low-level intake port. According to fluid mechanics principles, the draft force of the chimney effect is directly proportional to the height difference; the greater the height, the more significant the driving pressure difference formed by the gas density difference, and the more powerful the airflow. In practical applications in industries such as metallurgy and chemicals, gas pipelines are usually installed at a height of more than 5 meters to meet safety distance and production process requirements, while gas drainers are installed on the ground. Therefore, the height of the downcomer connecting the two is set within the range of 5 to 20 meters. When the downcomer height is less than 5 meters, the pressure difference between the high and low levels is too small, making it difficult to overcome pipeline resistance and form continuous and stable natural convection, which may lead to incomplete purging or excessively long purging time. When the downcomer height exceeds 20 meters, although theoretically greater draft force can be obtained, excessively high pipelines increase construction costs and maintenance difficulties.

[0034] In specific applications, the height of the downcomer is set to 5m, 8m, 10m, 15m or 20m, which can be selected according to the specific use case, and will not be listed here.

[0035] In some embodiments, optionally, such as Figure 5 As shown, in step S6, the preset purging time is 5 min to 10 min, and the preset concentration is 24 ppm.

[0036] Specifically, such as Figure 1 and Figure 5 As shown, the purging time setting of 5-10 minutes fully considers the time required for the complete process of air entering from the low-level inlet, flowing through each chamber of the gas drainer, converging into the downcomer, and exiting from the high-level exhaust port. A purging time that is too short may result in insufficient replacement of residual gas in all chambers and pipes, especially in distant chambers where replacement may lag. A purging time that is too long, while ensuring thorough replacement, will reduce operational efficiency. Setting a time range of 5-10 minutes ensures that in most industrial gas facilities, the chimney effect creates a stable airflow and completes at least one full cycle of gas replacement, allowing residual gas in each chamber and downcomer to be fully removed. The preset concentration is specifically set to 24 ppm. When the measured carbon monoxide concentration is below 24 ppm, it indicates that residual gas in the system has been completely removed, and the operating environment meets safety requirements.

[0037] In practical applications, the purging preset time can be set to 5 minutes, 8 minutes, or 10 minutes, which can be selected according to the specific usage situation, and will not be listed here.

[0038] In some embodiments, optionally, such as Figure 5 As shown, after step S6, when the carbon monoxide concentration is below 24 ppm, continue purging for 5 to 10 minutes to ensure that the residual gas is completely removed.

[0039] Specifically, such as Figure 5 As shown, although the carbon monoxide concentration has been proven to be below the safe threshold by sampling with the test head in step S6, considering the complexity of the multi-chamber structure inside the gas drainer and the potential for localized unevenness in the airflow distribution within the downcomer, the results of a single-point, single-test may not fully reflect the true condition of all areas of the entire system. The purpose of continuing purging for 5-10 minutes is twofold: firstly, to utilize the continuous airflow generated by the chimney effect to deeply replace any potentially stagnant areas within the system, ensuring that even if some areas are not fully compliant during the initial test, they can be thoroughly purged by extending the purging time; secondly, the extended purging time allows the airflow within the system to reach a more stable state, eliminating temporary concentration fluctuations caused by airflow fluctuations and creating a reliable safety redundancy. This design ensures that residual gas in each chamber, connecting pipe, and downcomer is completely removed.

[0040] In specific applications, the purging time can be set to 5mm, 8mm, or 10mm, depending on the actual usage situation, and will not be listed here.

[0041] According to the second aspect of this application, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, an embodiment of this application also proposes a purging and replacement device 100 for a gas equipment, used in the purging and replacement method of the gas equipment described in the above embodiment. The purging and replacement device 100 includes: a gas pipeline 1 for transporting gas; an upper gate valve 2 located below the gas pipeline 1 for cutting off the gas supply channel; a blind plate 3 detachably inserted into the flange below the upper gate valve 2, with a pad 31 provided on the non-gas source side of the blind plate 3 to form a ventilation gap between the blind plate 3 and the flange, the ventilation gap serving as a high-level exhaust port; and a downcomer 4 connected at the upper end to the upper gate valve 2 and extending downward at the lower end. Test head 5, located on the side wall at the bottom of downcomer 4, is used for sampling and testing; lower gate valve 6, located at the lower end of downcomer 4 and connected to the lower end of downcomer 4, is used to control the gas entering the drainer; gas drainer body 8, connected to lower gate valve 6, has multiple adjacent chambers inside, the upper ends of each chamber are connected to the main pipeline and then to lower gate valve 6; multiple drainer drain valves 9 are located at the lower ends of each chamber of gas drainer body 8, serving as low-level air inlets; air inlet 10 is located on one side of the lower end of gas drainer body 8, serving as an auxiliary air inlet.

[0042] Specifically, such as Figure 1 , Figure 3 and Figure 4As shown, the purging and replacement device 100 for gas equipment includes a gas pipeline 1, an upper gate valve 2, a blind flange 3, a downcomer 4, a test head 5, a lower gate valve 6, a drainer exhaust valve 7, a gas drainer body 8, multiple drainer drain valves 9, and an air inlet 10. The gas pipeline 1 is used to transport gas. The upper gate valve 2 is located below the gas pipeline 1 to cut off the gas supply. The blind flange 3 can be detachably inserted into the flange below the upper gate valve 2. A pad 31 is provided on the non-gas source side of the blind flange 3 to create a venting gap between the blind flange 3 and the flange. This venting gap serves as a high-level exhaust port for venting. The upper end of the downcomer 4 is connected to the upper gate valve 2, and the lower end extends downwards. The test head 5 is located on the side wall at the bottom of the downcomer 4 for sampling and testing. The lower gate valve 6 is located on... The lower end of the downcomer 4 is connected to the lower end of the downcomer 4 and is used to control the gas entering the drainer. The gas drainer body 8 is connected to the lower gate valve 6. The gas drainer body 8 has multiple chambers arranged sequentially and adjacently inside. The upper end of each chamber is connected to the main pipeline and then connected to the lower gate valve 6. Multiple drainer drain valves 9 are respectively set at the lower end of each chamber of the gas drainer body 8 as low-level air inlets for air intake. The air inlet 10 is set on one side of the lower end of the gas drainer body 8 as an auxiliary air inlet for air intake.

[0043] like Figure 1 As shown, Figure 1 The middle arrow indicates the gas flow trend. In the purging and replacement device 100 for gas equipment provided in this application, the gas pipeline 1 cooperates with the upper gate valve 2 to cut off and control the gas supply; the blind plate 3 and the pad 31 set on its non-gas source side form a controllable ventilation gap at the flange below the upper gate valve 2, serving as a high-level exhaust port with a chimney effect; the downcomer 4 connects the upper gate valve 2 and the lower gate valve 6, providing a gas flow channel and utilizing its vertical height to form a driving force for natural convection; the gas drainer body 8 has multiple sequentially adjacent chambers and each chamber Multiple drain valves 9 at the lower end of the chamber form a low-level air intake system, allowing air to enter each chamber in parallel from the drain valves. Air inlets 10 serve as auxiliary air inlets to further increase the air intake. The upper ends of each chamber converge into the main pipeline and connect to the lower gate valve 6, allowing the airflow from each chamber to merge before entering the downcomer 4. A test head 5 is located on the bottom side wall of the downcomer 4 for easy sampling and testing to confirm the replacement effect. A drain exhaust valve 7 is located on the upper part of the gas drainer body 8. The function of the drain exhaust valve 7 is to vent the drainer when air blockage occurs during operation. The purging and replacement device 100 for gas equipment provided in this application achieves complete purging and replacement of residual gas in the downcomer 4 and drainer without the need for external water sources, nitrogen, or other external media, and without relying on any power equipment. It relies solely on the chimney effect formed by the device's own structure to complete the purging and replacement of residual gas. It features simple structure, convenient operation, safety, reliability, and wide applicability.

[0044] Specifically, such as Figure 1 and Figure 2As shown, the height of the downcomer 4 is H, and H satisfies 5m≤H≤20m to ensure that a sufficient pressure difference is formed between the high-level exhaust port and the low-level air inlet to drive air flow.

[0045] In some embodiments, optionally, such as Figure 2 As shown, the high-level exhaust port can also be specifically configured as an exhaust valve 11, which is located on the bottom side of the upper gate valve 2 or the top of the downcomer 4.

[0046] Specifically, such as Figure 2 As shown, Figure 2 The middle arrow indicates the gas flow trend. The outlet valve 11 serves as an alternative to the blind flange 3 plus pad block 31 scheme. A specially designed outlet valve 11 can be used for the high-level exhaust port. This outlet valve 11 is installed at the bottom of the upper gate valve 2 or at the top of the downcomer 4. It remains closed during normal operation of the gas equipment to ensure the gas system's sealing. When purging and replacement operations are required, the outlet valve 11 is opened, allowing it to function as a high-level exhaust port with a chimney effect. This design shares the same technical principle as the blind flange 3 plus pad 31 solution, both providing a high-level gas outlet through the chimney effect. However, the operation differs. The outlet valve 11 can be quickly opened and closed by rotating the valve handle or through remote control. For safer gas source cutoff, the gas source can be cut off via the outlet valve 11, the upper gate valve 2, and a sealing water system. Specifically, an external water tank can be installed above the upper gate valve 2. Water from the tank can enter the gas pipeline at the top of the upper gate valve 2 through a valve. While the upper gate valve 2 cuts off the gas source, the water from the tank enters the pipeline through the valve, achieving a double seal with the upper gate valve 2. This design eliminates the need for mechanical operations such as inserting the blind flange 3 or adding the pad 31, making it particularly suitable for stationary gas facilities requiring frequent purging. Compared to existing technologies, this solution not only achieves natural convection purging without external gas source dependence but also further improves operational convenience and system sealing reliability, providing flexible options for different application scenarios.

[0047] In the description of this application, the term "multiple" refers to two or more. Unless otherwise expressly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0048] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the 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.

[0049] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A purging and replacement method for a gasification equipment, characterized in that, Includes the following steps: S1. Close the upper gate valve between the gas pipeline and the gas drainer body to cut off the gas supply channel; S2. Insert a blind flange at the flange below the upper gate valve and add a gasket on the non-air source side of the blind flange to form a ventilation gap between the blind flange and the flange, and the ventilation gap serves as a high-level exhaust port. S3. Open the drain valve at the lower end of the gas drainer body to discharge the sewage in each chamber of the gas drainer body; S4. Keep the drain valve of the drainer in the open position so that it serves as a low-level air inlet, and at the same time open the air inlet hole on one side of the lower end of the gas drainer body as an auxiliary air inlet. S5. By utilizing the height difference of the downcomer connecting the gas pipeline and the gas drainer body, air is allowed to enter from the drainer's drain valve and the air inlet, flow sequentially through the gas drainer body, the lower gate valve and the downcomer, and be discharged from the high-level exhaust port. S6. After the preset purging time, the exhaust gas is sampled and tested through the test head set on the side wall of the downcomer. When the carbon monoxide concentration is lower than the preset concentration, the purging and replacement are confirmed to be qualified. S7. Close the drain valve and air inlet of the drainer, remove the blind plate and pad, and open the upper gate valve to the working state.

2. The purging and replacement method for gas equipment according to claim 1, characterized in that, The high-level exhaust port is an exhaust valve, which is located on the bottom side of the upper gate valve or the top of the downcomer pipe. When the gas equipment needs to be purged, the gas outlet valve is opened as the high-level exhaust port. After the gas equipment has been purged, close the gas outlet valve.

3. The purging and replacement method for gas equipment according to claim 1, characterized in that, The low-position air inlet is multiple, including multiple drain valves installed at the lower end of the gas drainer body; During the purging of the gas equipment, multiple low-level air inlets are opened simultaneously, allowing air to enter in parallel, flow into the downcomer, and then be discharged upwards.

4. The purging and replacement method for gas equipment according to claim 1, characterized in that, The gas drainer body is provided with multiple chambers arranged in sequence and adjacent to each other. Each chamber is provided with a drain valve at the lower end. The upper ends of the multiple chambers are connected to the main pipeline and then connected to the lower gate valve. When purging the gas equipment, open the drain valves of all chambers to allow air to enter in parallel from each chamber.

5. The purging and replacement method for gas equipment according to claim 1, characterized in that, In step S2, the thickness of the pad is set to 5mm~10mm to adjust the ventilation gap and control the gas flow rate.

6. The purging and replacement method for gas equipment according to claim 1, characterized in that, In step S3, the time for draining the accumulated water is 3 to 10 minutes, until the water in each chamber is completely drained.

7. The purging and replacement method for gas equipment according to claim 1, characterized in that, In step S5, the height of the downcomer is 5m to 20m to ensure that a sufficient pressure difference is formed between the high-level exhaust port and the low-level air inlet to drive airflow.

8. The purging and replacement method for gas equipment according to claim 1, characterized in that, In step S6, the preset purging time is 5 min to 10 min, and the preset concentration is 24 ppm.

9. The purging and replacement method for gas equipment according to claim 1, characterized in that, After step S6, once the carbon monoxide concentration is below 24 ppm, continue purging for 5 to 10 minutes to ensure complete removal of residual gas.

10. A purging and replacement device for a gasification equipment, used in the purging and replacement method for a gasification equipment as described in any one of claims 1 to 9, characterized in that, The purging and replacement device for the gas equipment includes: Gas pipelines are used to transport gas. An upper gate valve is installed below the gas pipeline to cut off the gas supply channel; A blind flange is detachably inserted into the flange below the upper gate valve. A gasket is provided on the non-air source side of the blind flange to form a venting gap between the blind flange and the flange. The venting gap serves as a high-level exhaust port. The downcomer pipe is connected at its upper end to the upper gate valve and extends downward at its lower end. A test head, located on the side wall at the bottom of the downcomer tube, is used for sampling and testing; A lower gate valve is located at the lower end of the downcomer and connected to the lower end of the downcomer, used to control the gas entering the drainer; The gas drainer body is connected to the lower gate valve. The gas drainer body has multiple chambers arranged in sequence and adjacent to each other. The upper ends of each chamber are connected to the main pipeline and then connected to the lower gate valve. Multiple drain valves are respectively installed at the lower end of each chamber of the gas drain body, serving as low-level air inlets; An air inlet is located on one side of the lower end of the gas drainer body as an auxiliary air inlet.

Images