Skid-mounted natural gas dehydration and demercuration module

Abstract

The utility model discloses a skid-mounted natural gas dehydration and demercuration module. Comprising a natural gas filter separator, a natural gas gas-water separator, three molecular sieve adsorption towers, a regenerated gas heater, a regenerated gas cooler, a regenerated gas-water separator, a mercury removal bed, a mercury removal filter, a fuel gas tank, a main gas supply pipe, three branch gas inlet pipes, three branch gas outlet pipes, a first pressure reducing valve, a gas inlet switch valve, a gas outlet switch valve and a regenerated gas inlet pipe. According to the skid-mounted natural gas dehydration and demercuration module, a process system is optimized, the process system is simplified, the energy consumption of a device is reduced, the adaptability of the process system is improved, energy is saved, and the equipment and operation cost is reduced; the process skid is reasonably arranged, the device is highly integrated, the space of the skid is saved, operation, transportation and installation are convenient, and the equipment cost is saved.

Description

Technical Field

[0001] This utility model relates to the field of natural gas liquefaction equipment, specifically to a natural gas dehydration and mercury removal module before natural gas liquefaction. Background Technology

[0002] The natural gas liquefaction unit includes: a natural gas dehydration and mercury removal module, a natural gas deacidification module, and a natural gas refrigeration module. The natural gas dehydration and mercury removal module is used to filter, meter, dehydrate, and remove mercury from the raw gas, which contains impurities. The natural gas deacidification module is used to remove acidic gases such as CO2 and H2S from the raw gas. The natural gas refrigeration module is used to refrigerate the natural gas, liquefying the purified natural gas at room temperature into liquefied natural gas. Traditional natural gas dehydration and mercury removal module processes are complex, have poor adaptability, high energy consumption, high operating costs, and redundant designs, resulting in high system manufacturing costs, a large number of devices, and an inability to arrange them in a compact and reasonable manner. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a skid-mounted natural gas dehydration and mercury removal module with optimized process, low energy consumption, high adaptability, and reduced equipment cost.

[0004] To solve the above problems, the technical solution adopted by this utility model is as follows: a skid-mounted natural gas dehydration and mercury removal module, comprising: a natural gas filter separator, a natural gas gas-water separator, a molecular sieve adsorption tower, a regenerated gas heater, a regenerated gas cooler, a regenerated gas-water separator, a mercury removal bed, a mercury removal filter, and a fuel gas tank. The key feature is that: three molecular sieve adsorption towers are provided; the inlet of the natural gas filter separator is connected to the raw gas delivery pipe; the outlet of the natural gas filter separator is connected to the natural gas inlet of the natural gas deacidification module via a pipe; the natural gas outlet of the natural gas deacidification module is connected to the natural gas inlet of the natural gas gas-water separator via a pipe; the natural gas outlet of the natural gas gas-water separator is connected to the inlet of the main gas supply pipe; the outlet of the main gas supply pipe is connected to the inlet of three branch gas inlets; the outlets of the three branch gas inlets are connected to the top inlets of the three molecular sieve adsorption towers; the bottom outlets of the three molecular sieve adsorption towers are each connected to the inlet of the mercury removal bed via an outlet gas pipe; the outlet of the mercury removal bed is connected to the inlet of the mercury removal filter via a pipe; a first pressure reducing valve is connected in series on the main gas supply pipe; and an inlet valve is connected in series on each of the three branch gas inlets. The system includes three outlet gas pipes, each connected in series with an outlet gas valve. One end of the regenerated gas inlet pipe is connected to the main gas supply pipe, with the connection point located before the first pressure reducing valve. The other end of the regenerated gas inlet pipe is connected to three branch inlet pipes via pipes equipped with outlet valves, with each connection point located after the corresponding inlet gas valve. The inlet of the regenerated gas cooler is connected to the three branch inlet pipes via pipes equipped with outlet valves, with each connection point located after the corresponding inlet gas valve. The outlet of the regenerated gas cooler is connected to the regenerated gas water separator via a pipe. The gas outlets are connected as follows: outlet 1 of the regenerated gas-water separator is connected to the inlet of the fuel tank via a pipe with a second pressure reducing valve; outlet 2 of the regenerated gas-water separator is connected to the main gas supply pipe via a return pipe, with the connection point located behind the first pressure reducing valve; the inlet of the regenerated gas heater is connected to three outlet gas pipes via pipes with switch valves, with each connection point located in front of the corresponding outlet switch valve; and the outlet of the regenerated gas heater is connected to three outlet gas pipes via pipes with switch valves, with each connection point located in front of the corresponding outlet switch valve.

[0005] Furthermore, in the aforementioned skid-mounted natural gas dehydration and mercury removal module, the liquid phase recovery port of the natural gas gas-water separator is connected to the natural gas deacidification module via a first recovery pipe.

[0006] Furthermore, in the aforementioned skid-mounted natural gas dehydration and mercury removal module, the liquid phase recovery port of the regenerated gas-water separator is connected to the natural gas deacidification module via a second recovery pipeline.

[0007] Furthermore, in the aforementioned skid-mounted natural gas dehydration and mercury removal module, the inlet of the natural gas filter separator is also connected to the commissioning and recovery pipeline, the main gas supply pipeline is also connected to the deacidification failure recovery pipeline, and the outlet of the mercury removal filter is also connected to the dehydration failure recovery pipeline.

[0008] Furthermore, the aforementioned skid-mounted natural gas dehydration and mercury removal module also includes an instrumentation and control system junction box, an electrical system junction box, an online analysis cabinet, a natural gas filter separator, a natural gas-water separator, a molecular sieve adsorption tower, a regenerated gas heater, a regenerated gas cooler, a regenerated gas-water separator, a mercury removal bed, a mercury removal filter, and a fuel tank, all integrated onto a single skid.

[0009] Furthermore, in the aforementioned skid-mounted natural gas dehydration and mercury removal module: the skid is a rectangular two-layer steel structure frame; the natural gas filter separator and its inlet valve assembly are located at the front of the skid and arranged side-by-side; three molecular sieve adsorption towers and their inlet and outlet valve assemblies are located on one side of the skid behind the natural gas filter separator and are arranged at intervals. The top inlet valve assembly of the molecular sieve adsorption tower is located on the second-layer steel structure platform of the skid, and the bottom outlet valve assembly of the molecular sieve adsorption tower is located on the first-layer steel structure base of the skid. The regenerated gas-water separator, gas... The feed gas tank, mercury removal bed, mercury removal filter, and regenerated gas heater are located on one side of the skid behind the inlet valve group of the natural gas filter separator, and are arranged sequentially from front to back at intervals. The natural gas-water separator is located at the tail of the skid and behind the molecular sieve adsorption tower. The natural gas-water separator and the regenerated gas heater are arranged side by side on the left and right. A support frame is set on the second-layer steel structure platform of the skid above the regenerated gas-water separator. The regenerated gas cooler is installed on the top of the support frame. The instrumentation and control system junction box, electrical system junction box, and online analysis cabinet are located on the side of the skid.

[0010] Furthermore, in the aforementioned skid-mounted natural gas dehydration and mercury removal module, the manholes of the natural gas filter separator, molecular sieve adsorption tower, regenerated gas water separator, and mercury removal bed all face outwards, facilitating equipment loading, disassembly of packing materials, and internal equipment inspection; the side of the regenerated gas heater core removal mechanism faces outwards, facilitating core removal inspection and maintenance of the regenerated gas heater.

[0011] The advantages of this invention are as follows: the skid-mounted natural gas dehydration and mercury removal module optimizes the process system, simplifies the process system, reduces energy consumption, increases the adaptability of the process system, saves energy, and reduces equipment and operating costs. It can remove water content from natural gas to below 1 ppm and mercury content to 0.01 μg / Nm³. 3 The following features meet the requirements for natural gas liquefaction and the specifications for LNG commercial gas; the process skids are rationally laid out, the unit is highly integrated, saving skid space, facilitating operation, transportation and installation, and reducing equipment costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the process flow of the skid-mounted natural gas dehydration and mercury removal module described in this utility model.

[0013] Figure 2 This is a three-dimensional structural diagram of the skid-mounted natural gas dehydration and mercury removal module described in this utility model. Detailed Implementation

[0014] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0015] like Figure 1 , Figure 2As shown, the skid-mounted natural gas dehydration and mercury removal module includes: a natural gas filter separator 1, a natural gas gas-water separator 3, a molecular sieve adsorption tower, a regenerated gas heater 7, a regenerated gas cooler 8, a regenerated gas-water separator 9, a mercury removal bed 11, a mercury removal filter 12, and a fuel gas tank 10. Three molecular sieve adsorption towers are provided: a first molecular sieve adsorption tower 4, a second molecular sieve adsorption tower 5, and a third molecular sieve adsorption tower 6. While one molecular sieve adsorption tower is adsorbing and dehydrating, another is heating and regenerating, and the third is purging and cooling. The process states of the three molecular sieve adsorption towers are switched between each other via valves. The inlet of the natural gas filter separator 1 is used to connect with the raw material... The gas delivery pipeline connects the outlet of the natural gas filter separator 1 to the natural gas inlet of the natural gas deacidification module 2 via a pipeline. The natural gas outlet of the natural gas deacidification module 2 is connected to the natural gas inlet of the natural gas gas-water separator 3 via a pipeline. The natural gas outlet of the natural gas gas-water separator 3 is connected to the inlet of the main gas supply pipe 25. The outlet of the main gas supply pipe 25 is connected to the inlet of three branch gas inlet pipes 26. The outlets of the three branch gas inlet pipes 26 are connected to the top inlet of three molecular sieve adsorption towers. The bottom outlets of the three molecular sieve adsorption towers are connected to the inlet of the mercury removal bed 11 via an outlet gas pipe 27. The outlet of the mercury removal bed 11 is connected to the inlet of the mercury removal filter 12 via a pipeline. A first pressure reducing valve 13 is connected in series to the main air supply pipe 25. Inlet valves 28 are connected in series to each of the three branch inlet pipes 26, and outlet valves 29 are connected in series to each of the three outlet outlet pipes 27. One end of the regenerated gas supply pipe 24 is connected to the main air supply pipe 25, with the connection point located in front of the first pressure reducing valve 13. The other end of the regenerated gas supply pipe 24 is connected to each of the three branch inlet pipes 26 via pipes equipped with valves, with each connection point located behind the corresponding inlet valve 28. The inlet of the regenerated gas cooler 8 is connected to each of the three branch inlet pipes 26 via pipes equipped with valves, with each connection point located behind the corresponding inlet valve 28. The outlet of 8 is connected to the inlet of the regenerated gas water separator 9 through a pipe. The outlet of the regenerated gas water separator 9 is connected to the inlet of the fuel tank 10 through a pipe with a second pressure reducing valve 14. The outlet of the regenerated gas water separator 9 is connected to the main gas supply pipe 25 through a return pipe 17, and the connection point is located behind the first pressure reducing valve 13. The inlet of the regenerated gas heater 7 is connected to three outlet pipes 27 through pipes with switch valves, and each connection point is located in front of the corresponding outlet switch valve 29. The outlet of the regenerated gas heater 7 is connected to three outlet pipes 27 through pipes with switch valves, and each connection point is located in front of the corresponding outlet switch valve 29.

[0016] The intake is equipped with only one natural gas filter separator 1. By increasing the diameter and height of the equipment, the requirements for buffering, gas-liquid separation and filtering of solid impurities in the intake natural gas can be met simultaneously.

[0017] Three molecular sieve adsorption towers are installed. One tower adsorbs and dehydrates the natural gas after depressurization. The other tower uses the natural gas before depressurization for sequential cold blowing and hot blowing. Because the regenerated gas pressure is high, it can be returned to the main gas supply pipe 25 through return pipe 17, avoiding the need for repressurization and backflow, thus reducing costs and energy consumption. Simultaneously, the heat carried by the cold blowing in the first tower is used for the hot blowing in the second tower, saving energy for the regenerated gas heater 7.

[0018] The regenerated gas-water separator 9 is equipped with two outlets: one for recirculation via return pipe 17, and the other for pressure reduction via the second pressure reducing valve 14 before entering the fuel gas tank 10. The second pressure reducing valve 14 can flexibly adjust the fuel gas usage according to the fuel gas demand, and the remaining regenerated gas can be recirculated for use in the molecular sieve adsorption tower, making the process system highly adaptable.

[0019] During operation, the raw gas enters the natural gas filter separator 1 through the raw gas delivery pipe for buffering, gas-liquid separation, and filtration of large particulate impurities. Then, the raw gas enters the natural gas deacidification module 2 for deacidification. A flow meter for detecting the flow rate of the raw natural gas is installed on the pipeline between the natural gas filter separator 1 and the natural gas deacidification module 2. Next, the raw gas enters the natural gas-water separator 3 to separate most of the water. In this embodiment, the inlet switch valve 28 and outlet switch valve 29 on the pipelines containing the second molecular sieve adsorption tower 5 and the third molecular sieve adsorption tower 6 are temporarily closed. Through valve control, a small portion of the natural gas exiting the natural gas-water separator 3 becomes regenerated gas and flows along... Figure 1 The red arrow indicates that the gas enters the third molecular sieve adsorption tower 6 to purge and cool the molecular sieve inside the tower. Then, the gas enters the regeneration gas heater 7 for further heating. The heated regeneration gas then flows along... Figure 1 The blue arrow indicates that the gas enters the second molecular sieve adsorption tower 5, where the molecular sieve is heated and regenerated to dry it and restore its adsorption capacity. The gas then enters the regenerated gas cooler 8 for cooling, followed by gas-liquid separation in the regenerated gas-water separator 9. The regenerated gas after gas-liquid separation can be depressurized by the second pressure reducing valve 14 and stored in the fuel gas tank 10, or it can be returned to the main gas supply pipeline 25 via the return pipeline 17 for reuse. Valve control ensures that other natural gas from the natural gas-water separator 3, after being depressurized by the first pressure reducing valve 13, flows along... Figure 1 The green arrow indicates that the gas enters the first molecular sieve adsorption tower 4 for adsorption and dehydration. The dehydrated raw gas then enters the mercury removal bed 11 for mercury removal. Finally, the raw gas enters the mercury removal filter 12 to filter impurities, thus obtaining purified natural gas.

[0020] In this embodiment, the liquid phase recovery port of the natural gas gas-water separator 3 is connected to the natural gas deacidification module 2 via a first recovery pipe 15. The liquid phase recovery port of the regenerated gas-water separator 9 is connected to the natural gas deacidification module 2 via a second recovery pipe 16. This configuration returns the liquid phase separated from the natural gas to the natural gas deacidification module 2 via the recovery pipes, preventing the liquid phase from entering the sewage system, thus reducing the cost of sewage storage, transportation, and treatment. Furthermore, the water recovery reduces the amount of water needed to replenish the natural gas deacidification module 2, saving water resources.

[0021] The inlet of the natural gas filter separator 1 is also connected to the commissioning and recovery pipeline 18, the main gas supply pipeline 25 is also connected to the deacidification unqualified recovery pipeline 19, and the outlet of the mercury removal filter 12 is also connected to the dehydration unqualified recovery pipeline 20. With this setup, unqualified natural gas can be recovered and reused during start-up and commissioning, avoiding natural gas waste and saving costs.

[0022] In this embodiment, an instrumentation and control system junction box 21, an electrical system junction box 22, an online analysis cabinet 23, an instrumentation and control system junction box 21, an electrical system junction box 22, an online analysis cabinet 23, a natural gas filter separator 1, a natural gas gas-water separator 3, a molecular sieve adsorption tower, a regenerated gas heater 7, a regenerated gas cooler 8, a regenerated gas-water separator 9, a mercury removal bed 11, a mercury removal filter 12, and a fuel gas tank 10 are also integrated on a single skid.

[0023] Online sampling interfaces are installed at the rear end of the natural gas filter separator 1, and at the front and rear ends of the molecular sieve adsorption tower. These sampling interfaces are connected to the online analysis cabinet 23. The online analysis cabinet 23 can monitor the acid content of the gas source, the acid content after the natural gas deacidification module 2, and the water content after the molecular sieve adsorption tower 4. It can analyze the gas source situation in real time and determine whether the deacidification and dehydration systems meet product requirements.

[0024] The skid is a rectangular two-layer steel frame structure. The natural gas filter separator 1 and its inlet valve assembly are located at the front of the skid, arranged side-by-side. Three molecular sieve adsorption towers and their inlet and outlet valve assemblies are located on one side of the skid behind the natural gas filter separator 1, spaced apart front to back. The top inlet valve assembly of the molecular sieve adsorption towers is located on the second-layer steel structure platform of the skid, and the bottom outlet valve assembly is located on the first-layer steel structure base of the skid. The equipment piping is tightly packed for easy operation and maintenance. The system includes a regenerated gas-water separator 9, a fuel gas tank 10, a mercury removal bed 11, and a mercury removal filter 1. 2. The regenerated gas heater 7 is located on one side of the skid behind the inlet valve group of the natural gas filter separator 1, and is arranged in sequence from front to back at intervals. The natural gas-water separator 3 is located at the tail of the skid and behind the molecular sieve adsorption tower. The natural gas-water separator 3 and the regenerated gas heater 7 are arranged side by side. A support frame is set on the second-layer steel structure platform of the skid above the regenerated gas-water separator 9. The regenerated gas cooler 8 is installed on the top of the support frame. The instrumentation and control system junction box 21, the electrical system junction box 22, and the online analysis cabinet 23 are set on the side of the skid to facilitate operation, inspection and maintenance.

[0025] The manholes of the natural gas filter separator 1, molecular sieve adsorption tower, regenerated gas water separator 9, and mercury removal bed 11 all face outwards, facilitating the loading and unloading of packing materials and internal inspection of the equipment; the side of the regenerated gas heater 7 with the core removal mechanism faces outwards, facilitating the core removal and maintenance of the regenerated gas heater 7.

[0026] The various devices within the skid are arranged compactly according to the process route to meet the process requirements. This reduces the length of process piping and saves skid space, allowing for smaller skids that not only save costs but also facilitate transportation.

[0027] The process piping is arranged in two layers to make full use of the space inside the skid and ensure that the skid is as small as possible. While ensuring that the lower layer is easy to operate, the height of the skid is reduced and controlled within the transportation height limit to meet transportation requirements.

[0028] Pipes exceeding the transport height of the skid and those connected within the skid are flanged, ensuring that pipes exceeding the transport height are prefabricated in the factory and can be directly assembled on-site. This solves the transport height issue and avoids secondary welding on-site, saving costs.

[0029] The regenerated gas cooler 8 and the regenerated gas water separator 9 are arranged vertically to ensure that the gas and liquid phases cooled by the regenerated gas cooler 8 can flow from top to bottom into the regenerated gas water separator 9, thus avoiding the accumulation of liquid.

Claims

1. Skid-mounted natural gas dehydration and mercury removal module, including: The invention comprises a natural gas filter separator, a natural gas gas-water separator, a molecular sieve adsorption tower, a regenerated gas heater, a regenerated gas cooler, a regenerated gas-water separator, a mercury removal bed, a mercury removal filter, and a fuel gas tank. Its features include: three molecular sieve adsorption towers; the inlet of the natural gas filter separator is connected to the raw gas delivery pipe; the outlet of the natural gas filter separator is connected to the natural gas inlet of the natural gas deacidification module via a pipeline; the natural gas outlet of the natural gas deacidification module is connected to the natural gas inlet of the natural gas gas-water separator via a pipeline; the natural gas outlet of the natural gas gas-water separator is connected to the inlet of the main gas supply pipe; the outlet of the main gas supply pipe is connected to the inlet of three branch gas inlets; the outlets of the three branch gas inlets are connected to the top inlets of the three molecular sieve adsorption towers; the bottom outlets of the three molecular sieve adsorption towers are each connected to the inlet of the mercury removal bed via an outlet gas pipe; the outlet of the mercury removal bed is connected to the inlet of the mercury removal filter via a pipeline; a first pressure reducing valve is connected in series on the main gas supply pipe; an inlet switch valve is connected in series on each of the three branch gas inlets; and an outlet valve is connected in series on each of the three outlet gas pipes. The system includes a switch valve, a regenerated gas inlet pipe (one end connected to the main gas supply pipe with the connection point in front of the first pressure reducing valve), a regenerated gas inlet pipe (the other end connected to three branch inlet pipes via pipes with switch valves, each connection point located behind the corresponding inlet switch valve), a regenerated gas cooler inlet connected to three branch inlet pipes via pipes with switch valves, each connection point located behind the corresponding inlet switch valve), a regenerated gas cooler outlet connected to the regenerated gas water separator inlet via a pipe), a regenerated gas water separator outlet 1 connected to the fuel tank inlet via a pipe with a second pressure reducing valve), a regenerated gas water separator outlet 2 connected to the main gas supply pipe via a return pipe with the connection point located behind the first pressure reducing valve), a regenerated gas heater inlet connected to three outlet pipes via pipes with switch valves, each connection point located in front of the corresponding outlet switch valve), and a regenerated gas heater outlet connected to three outlet pipes via pipes with switch valves, each connection point located in front of the corresponding outlet switch valve.

2. The skid-mounted natural gas dehydration and mercury removal module according to claim 1, characterized in that: The liquid phase recovery port of the natural gas gas-water separator is connected to the natural gas deacidification module through the first recovery pipeline.

3. The skid-mounted natural gas dehydration and mercury removal module according to claim 1, characterized in that: The liquid phase recovery port of the regenerated gas-water separator is connected to the natural gas deacidification module through a second recovery pipeline.

4. The skid-mounted natural gas dehydration and mercury removal module according to claim 1, characterized in that: The inlet of the natural gas filter separator is also connected to the commissioning and recovery pipeline, the main gas supply pipeline is also connected to the deacidification failure recovery pipeline, and the outlet of the mercury removal filter is also connected to the dehydration failure recovery pipeline.

5. The skid-mounted natural gas dehydration and mercury removal module according to claim 1, characterized in that: It also includes instrumentation and control system junction boxes, electrical system junction boxes, online analysis cabinets, natural gas filter separators, natural gas gas-water separators, molecular sieve adsorption towers, regenerated gas heaters, regenerated gas coolers, regenerated gas-water separators, mercury removal beds, mercury removal filters, and fuel tanks, all integrated on a single skid.

6. The skid-mounted natural gas dehydration and mercury removal module according to claim 5, characterized in that: The skid is a rectangular two-layer steel frame. The natural gas filter separator and its inlet valve assembly are located at the front of the skid and arranged side by side. Three molecular sieve adsorption towers and their inlet and outlet valve assemblies are located on one side of the skid behind the natural gas filter separator and are arranged at intervals. The top inlet valve assembly of the molecular sieve adsorption tower is located on the second-layer steel structure platform of the skid, and the bottom outlet valve assembly of the molecular sieve adsorption tower is located on the first-layer steel structure base of the skid. The regenerated gas water separator, fuel gas tank, mercury removal bed, mercury removal filter, and regenerated gas heater are located on one side of the skid behind the inlet valve assembly of the natural gas filter separator and are arranged at intervals from front to back. The natural gas water separator is located at the rear of the skid and behind the molecular sieve adsorption towers. The natural gas water separator and the regenerated gas heater are arranged side by side. A support frame is installed on the second-layer steel structure platform of the skid above the regenerated gas water separator. The regenerated gas cooler is installed on the top of the support frame. The instrumentation and control system junction box, electrical system junction box, and online analysis cabinet are located on the side of the skid.

7. The skid-mounted natural gas dehydration and mercury removal module according to claim 6, characterized in that: The manholes of the natural gas filter separator, molecular sieve adsorption tower, regenerated gas water separator, and mercury removal bed all face outwards, facilitating the loading and unloading of packing materials and internal inspection of the equipment; the side of the regenerated gas heater core removal device faces outwards, facilitating the core removal and maintenance of the regenerated gas heater.

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