Air filter and air compressor

Abstract

The utility model discloses an air filter and an air compressor, the air filter comprises a box body, two ends of the box body are respectively provided with an air inlet and an air outlet, the box body is internally provided with a preheater and a filter chamber, and the preheater is close to the air inlet. According to the utility model, the air filter is combined with the preheater, and air is heated before entering the filter chamber, so that the temperature of the air entering the air compressor is constant, and the air compressor is ensured to operate under high-efficiency and stable working conditions. Meanwhile, the compressed air directly enters the reactor of the maleic anhydride device, so that the use of a heater in front of the reactor is avoided, the steam consumption of the heater is reduced, and the operation cost of the whole maleic anhydride device is reduced.

Description

Technical Field

[0001] The utility model relates to the field of air compressors, and particularly relates to an air filter and an air compressor. Background Art

[0002] An air compressor is a core device for providing oxidation air in a maleic anhydride device. It is a device that converts the mechanical energy of a prime mover into gas pressure energy, pressurizes and heats the compressed air and sends it to the maleic anhydride oxidation reactor to participate in the oxidation reaction. Due to the reaction temperature requirements, the air needs to be preheated to a relatively high temperature by steam before entering the reactor, and it has a high dependence on steam. In traditional butane oxidation maleic anhydride processes, electric compressors are used. With the development of the large-scale of the device, electric compressors can no longer meet the increasing demand for air supply and the requirements of energy conservation and consumption reduction. Steam-driven air compressors have begun to be widely used. Improving the compressor efficiency, saving steam consumption, and reducing operating costs have become the key to energy conservation and consumption reduction.

[0003] In the traditional process, an air filter is set at the inlet of the air compressor, which is only used to filter dust and impurities in the air. However, due to the change of seasons and day and night, there has always been a situation where the intake air temperature deviates from the optimal design temperature during the operation of the air compressor. Especially in the vast northern regions where the winter temperature is low, the day-night temperature difference is large, the air contains a large amount of water, the filter element of the air filter is easy to be blocked, the backwashing period is short, and the water corrosion of the air pipeline is significant, which affects the safe, efficient and stable operation of the compressor. Water droplets entering the compressor can seriously break through the compressor impeller and cause the maleic anhydride device to stop. Summary of the Utility Model

[0004] To solve the problems of the prior art, the utility model provides an air filter and an air compressor.

[0005] The purpose of the utility model is achieved by the following technical solutions:

[0006] An air filter includes a box body, and an air inlet and an air outlet are respectively arranged at both ends of the box body. A preheater and a filtration chamber are arranged inside the box body, and the preheater is close to the air inlet.

[0007] Further, the preheater is an air preheater, which is a conventional structure in the art; or the preheater includes a preheating unit, and the preheating unit includes finned tubes and a fixing frame for fixing the finned tubes. The finned tubes are fixedly connected to the fixing frame.

[0008] Further, the finned tube includes a base tube and fins. The fins are located outside the base tube, and the base tube and the fins are fixedly connected. The two ends of the base tube are the water inlet end and the water outlet end; the fixing frame includes a fixing plate, a fixing rod and a fastening brace. The fixing plate is in the vertical direction, and a part of the finned tube passes through the fixing plate. The fixing rod is in the horizontal direction. The fixing plate and the fixing rod enclose a frame structure. The side of the frame structure is provided with a fastening brace, and the fixing plate, the fixing rod and the fastening brace are fixedly connected. Air passes through the preheater through the gaps between the finned tubes and heats the air.

[0009] Further, the preheating unit is single or multiple, and multiple preheating units are connected in parallel; the finned tubes are single or multiple, and multiple finned tubes are connected in parallel; when there are multiple finned tubes, the water inlet ends of multiple base tubes are connected to the water inlet through a water inlet header, and the water outlet ends of multiple base tubes are connected to the water outlet through a water outlet header.

[0010] Further, a silencer is provided inside the box body, and the silencer is close to the air outlet.

[0011] Further, a service room is provided between the preheater and the filter chamber.

[0012] Further, a transition section is provided between the filter chamber and the silencer.

[0013] Further, a rain shelter is provided outside the air inlet.

[0014] Further, a filter element is provided inside the filter chamber; a backwashing device is provided at the top of the filter chamber, and a dust discharge port is provided at the bottom of the filter chamber. After the dusty air is filtered, the dust is adsorbed on the high-efficiency filter element, and the backwashing device performs the backwashing self-cleaning process, and the dust is backwashed and self-cleaned, prolonging the service life of the filter element and reducing the production cost investment.

[0015] Further, the backwashing device is connected to a clean air gas source.

[0016] Further, a control cabinet is provided in the filter chamber. The control cabinet is connected to the backwashing device and is used for the on-line self-cleaning of the filter element in the filter, that is, the air filter is a self-cleaning air filter. Specifically, the control cabinet realizes the on-line self-cleaning of the filter element in the filter through three different program settings (time program, differential pressure program, humidity program). The control cabinet includes a PLC, and the PLC performs the backwashing self-cleaning process according to the set time sequence. When the resistance loss value exceeds 600 Pa, the PLC controls the backwashing self-cleaning process according to the differential pressure sequence (the backwashing time is 0.1 - 0.2 seconds). When the air humidity > 75%, the PLC controls the backwashing self-cleaning process according to the sequential cycle (the backwashing time is 0.1 - 0.2 seconds), and other high-efficiency filter elements work normally.

[0017] Further, a blower is also provided at the bottom of the filtration chamber for collecting the dust and impurities removed by the backwashing device and discharging them into the atmosphere.

[0018] Further, the main components of the air filter (e.g., preheater, service chamber, filtration section, filtration chamber (except for the filter element), muffler) are made of metal (e.g., carbon steel, stainless steel). After adding the preheater, the air temperature is increased from the previous annual average temperature of 9.9 °C to 31 °C, and the humidity in the air is reduced (i.e., the content of effective gas components in the air is increased), improving the air dryness, thereby solving the problem of wet air corroding the equipment. The content of effective gas components in the air is increased.

[0019] An air compressor includes the above-mentioned air filter, and the air outlet of the air filter is connected to the air inlet of the air compressor.

[0020] Further, the air compressor is connected to a steam turbine and is driven by the steam turbine.

[0021] Further, the steam turbine is provided with a steam inlet and a steam outlet. The steam inlet is connected to a high-pressure steam gas source, and the steam outlet is connected to a condenser.

[0022] Further, the air outlet of the air compressor is connected to the reactor of the maleic anhydride unit for delivering air to the reactor of the maleic anhydride unit.

[0023] After the air is preheated by the preheater, it flows through the filter element in the filtration chamber for filtration to remove dust and mechanical impurities in the air. The clean air flows out of the air filter after passing through the transition section and being noise-reduced by the muffler; it enters the air compressor, and the air compressor compresses, heats up, and boosts the air under the drive of the steam turbine. The compressed air enters the reactor of the maleic anhydride unit.

[0024] Advantages of the present utility model:

[0025] The present utility model combines the air filter with the preheater. The preheater is installed in the air filter to heat the air before it enters the filtration chamber, ensuring a constant temperature of the air entering the air compressor, and thus ensuring the operation of the compressor under efficient and stable conditions; at the same time, the compressed air directly enters the reactor of the maleic anhydride unit, avoiding the use of a heater before the reactor, reducing the steam consumption for the heater, and reducing the overall operating cost of the maleic anhydride unit. Description of the drawings

[0026] Figure 1 is a schematic structural diagram of the air filter in Embodiment 1.

[0027] Figure 2 is a schematic structural diagram of the air filter (with a rack) in Embodiment 1.

[0028] Figure 3 It is a schematic structural diagram of a single finned tube in Embodiment 1.

[0029] Figure 4 It is a top - view structural schematic diagram of the pre - heater of a single pre - heating unit in Embodiment 1.

[0030] Figure 5 It is a front - view structural schematic diagram of the pre - heater of a single pre - heating unit in Embodiment 1.

[0031] Figure 6 It is a front - view structural schematic diagram of the pre - heater of multiple pre - heating units in Embodiment 1.

[0032] Figure 7 It is a schematic diagram of a steam turbine - driven air compressor in Embodiment 2.

[0033] Figure 8 It is a schematic diagram of a steam turbine - driven air compressor in Comparative Example 2.

[0034] In the figure: 1. Air filter, 2. Air compressor, 3. Steam turbine, 4. Condenser, 5. Heater, 6. Box body, 7. Pre - heater, 8. Filter chamber, 9. Silencer, 10. Service room, 11. Transition section, 12. Rain - proof shed, 13. Back - blowing device, 14. Fan, 15. Program control cabinet, 16. Air inlet, 17. Air outlet, 18. Dust discharge port, 19. Rack, 20. Base tube, 21. Fins, 22. Water inlet, 23. Water outlet, 24. Inlet water header, 25. Outlet water header, 26. Fixed rod, 27. Fixed plate, 28. Tightening brace, 29. Pre - heating unit, 30. Water inlet end, 31. Water outlet end. Detailed implementation manners

[0035] The following non - restrictive embodiments can enable those of ordinary skill in the art to more comprehensively understand the present utility model, but do not limit the present utility model in any way.

[0036] Embodiment 1

[0037] As Figures 1-6As shown in the figure, an air filter includes a box body 6. An air inlet 16 and an air outlet 17 are respectively provided at two ends of the box body 6. A preheater 7 and a filter chamber 8 are arranged inside the box body 1. The preheater 7 is close to the air inlet 16. The preheater 7 is a conventional structure in the art; or the preheater 7 includes a preheating unit 29. The preheating unit 29 includes finned tubes and a fixing frame for fixing the finned tubes. The finned tubes are fixedly connected to the fixing frame; the finned tubes include a base tube 20 and fins 21. The fins 21 are located outside the base tube 20. The base tube 21 and the fins 20 are fixedly connected; the fixing frame includes a fixing plate 27, fixing rods 26 and fastening braces 28. The fixing plate 27 is in the vertical direction. Part of the finned tubes pass through the fixing plate 27. The fixing rods 26 are in the horizontal direction. The fixing plate 27 and the fixing rods 26 enclose a frame structure. The fastening braces 28 are arranged on the side surface of the frame structure. The fixing plate 26, the fixing rods 27 and the fastening braces 28 are fixedly connected to each other; the two ends of the base tube 20 are a water inlet end 30 and a water outlet end 31. The preheating unit 29 is single or multiple. Multiple preheating units 29 are connected in parallel; the finned tubes are single or multiple. Multiple finned tubes are connected in parallel; when there are multiple finned tubes, the water inlet ends 29 of multiple base tubes 20 are connected to the water inlet 22 through a water inlet header 24, and the water outlet ends 31 of multiple base tubes 20 are connected to the water outlet 23 through a water outlet header 25. Air passes through the gaps between the finned tubes through the preheater 7 and the air is heated. A silencer 9 is arranged inside the box body 6. The silencer 9 is close to the air outlet 17. A transition section 11 is arranged between the filter chamber 8 and the silencer 9. A service chamber 10 is arranged between the preheater 7 and the filter chamber 8. A rain shelter 12 is arranged outside the air inlet 16. A filter element is arranged inside the filter chamber 8. A backwashing device 13 is arranged at the top of the filter chamber 8. The backwashing device 13 is connected to a clean air gas source; a dust discharge port 18 is arranged at the bottom of the filter chamber 8. A blower 14 is also arranged at the bottom of the filter chamber 8. A program control cabinet 15 is arranged in the filter chamber 8. The program control cabinet 15 is connected to the backwashing device 13. After the dust-containing air is filtered, the dust is adsorbed on the high-efficiency filter element, and the backwashing device 13 performs a backwashing self-cleaning process. A rack 19 is arranged at the bottom of the box body 6 of the air filter.

[0038] Air at a pressure of 101.3 Kpa(A) and a temperature of 9.9 °C enters through the rain shelter 12 of the air filter 1, and the air is heated to the constant intake temperature of 31 °C of the air compressor 2 with 95 °C hot water. Then, the dust and mechanical impurities in the air are removed by the filter element in the filter chamber 8. The clean air enters the axial flow air compressor 2 after being reduced in noise through the transition section 11 and the silencer 9; Another path selects a clean instrument (clean air) gas source with a pressure of 0.7 Mpa and a dew point of -60 °C as the backwashing gas for the filter element. The MU centralized control cabinet 15 realizes the on-line self-cleaning of the filter element in the air filter 1 through three different program settings (time program, differential pressure program, humidity program).

[0039] Example 2

[0040] As Figure 7 shown, an air compressor includes the air filter 1 in Example 1. The air outlet of the air filter 1 is connected to the air inlet of the air compressor 2. The air compressor 2 is connected to a steam turbine 3 and is driven by the steam turbine 3. The steam turbine 3 is provided with a steam inlet and a steam outlet. The steam inlet is connected to a high-pressure steam gas source, and the steam outlet is connected to a condenser 4. The air outlet of the air compressor 2 is connected to the reactor of the maleic anhydride plant and is used to transport air to the reactor of the maleic anhydride plant.

[0041] The operation process of the air compressor is as follows:

[0042] The 12 Mpa, 525 °C high-pressure superheated steam from the thermal power plant enters the steam turbine 3, converts the steam thermal energy into mechanical energy to do external work to drive the air compressor 2 to rotate. The remaining thermal energy that cannot be completely converted enters the shell-and-tube condenser 4 to exchange heat with cooling water. The condensate obtained is sent to the thermal power plant by a vertical multi-stage condensate pump for heating and recycling, and the non-condensable steam is discharged to the atmosphere. At the same time, the air entering the air compressor 2 uses mechanical energy to be converted into pressure energy to compress the gas, and the air pressure is raised to 275 Kpa(A) and the temperature is 161 °C. The compressed air with a pressure of 275 Kpa(A) and a temperature of 161 °C is mixed with the 130 °C n-butane raw material gas and sent to the reactor in the maleic anhydride plant area for oxidation reaction.

[0043] Comparative Example 1

[0044] The difference from Example 1 is that no preheater is provided.

[0045] Air with a pressure of 101.3 Kpa(A) and a temperature of 9.9 °C enters from the rain shelter 12 of the air filter 1 and passes through the filter element in the filter chamber 8 to remove dust and mechanical impurities in the air. The clean air passes through the transition section 11 and the muffler 9 for noise reduction and then enters the axial-flow air compressor 2. Another path selects a 0.7 Mpa, dew point -60 °C clean instrument (clean air) gas source as the backflush gas for the filter element, and the MU centralized control cabinet 15 realizes the online self-cleaning of the filter element in the air filter 1 through three different program settings (time program, differential pressure program, humidity program).

[0046] Comparative Example 2

[0047] As Figure 8As shown in the figure, an air compressor includes an air filter in Comparative Example 1. The air outlet of the air filter is connected to the air inlet of the air compressor 2. The air compressor 2 is connected to a steam turbine 3 and is driven by the steam turbine 3. The steam turbine 3 is provided with a steam inlet and a steam outlet. The steam inlet is connected to a high-pressure steam gas source, and the steam outlet is connected to a condenser 4. The air outlet of the air compressor 2 is connected to a heater 5. The heater 5 is connected to the reactor of the maleic anhydride plant and is used to convey air to the reactor of the maleic anhydride plant. The heater 5 includes a shell side and a tube side. The shell side of the heater is connected to the air outlet of the air compressor 2, and the tube side of the heater 5 is connected to a medium-pressure steam gas source. Compressed air enters the shell side of the heater 5 and exchanges heat with the medium-pressure steam in the tube side.

[0048] The operation process of the air compressor is as follows:

[0049] The 12 Mpa, 525 °C high-pressure superheated steam from the thermal power plant enters the steam turbine 3. The thermal energy of the steam is converted into mechanical energy to do external work to drive the air compressor 2 to rotate. The remaining thermal energy that cannot be completely converted enters the shell-and-tube condenser 4 to exchange heat with cooling water. The condensate obtained is sent to the thermal power plant by a vertical multi-stage condensate pump for heating and recycling. The non-condensable steam is discharged to the atmosphere. At the same time, the air entering the air compressor 2 uses mechanical energy to be converted into pressure energy to compress the gas, and the air pressure is increased to 275 Kpa(A) and the temperature is 126 °C. The compressed air with a pressure of 275 Kpa(A) and a temperature of 126 °C enters the shell side of the heater 5 to exchange heat with the 2.3 Mpa, 285 °C medium-pressure steam in the tube side, and the air temperature is increased to 161 °C. Then it is mixed with the 130 °C n-butane feed gas and sent to the reactor in the maleic anhydride plant area for oxidation reaction.

[0050] It can be seen from Example 2 and Comparative Example 2 that the reactor requires the air temperature to be not lower than 160 °C. In Comparative Example 2, a heater is set after the air compressor 2 to increase the compressed air at the outlet of the air compressor at 126 °C to 161 °C to meet the air inlet requirement of the reactor. After calculation, at the annual average temperature of 9.9 °C at the project location, 90% of the whole year is deviated from the high-efficiency point of the compressor, and the output shaft power increases by about 2.5% under the maximum working condition. Compared with Comparative Example 2, in Example 2, the air is first preheated by the preheater 7 through the air filter 1, and the air inlet temperature of the air compressor 2 is kept constant at 31 °C. After being compressed by the air compressor 2, the outlet pressure is 275 Kpa(A), and the temperature can be increased from 126 °C before to 161 °C, meeting the temperature of the maleic anhydride reactor, and the total energy consumption of the air entering the reactor after compression is reduced.

[0051] Example 2 and Comparative Example 2 are compared, and the energy-saving cost calculation is as follows (calculated at 0.5 yuan per kilowatt-hour of electricity price and the compressor operates for 8000 hours throughout the year):

[0052] 1. In Comparative Example 2, for the intake process air compressor 2 with an annual average intake temperature of 9.9 °C, the outlet temperature is 126 °C, the pressure is 12 Mpa, the consumption of high-pressure steam at 525 °C is 74 t / h, the shaft power is 23674 KW / h, the consumption of medium-pressure steam at 2.3 Mpa and 285 °C is 9.4 t / h, the thermal power is 5177 KW / h, the outlet temperature of the heater 5 is 161 °C, and the total power output of the air before entering the reactor is: 23674 KW / h + 5177 KW / h = 28851 KW / h.

[0053] 2. In Example 2, after adding the preheater, for the intake process air compressor 2 with an intake temperature of 31 °C, the outlet temperature is 161 °C, the consumption of high-pressure steam at 12 Mpa is 79 t / h, the shaft power is 25291 KW / h, the consumption of hot water at 95 °C is 100 t / h, the thermal power is 2972 KW / h, the consumption of steam at 2.3 Mpa is 0 t / h, the thermal power is 0 KW, and the total power output of the air before entering the reactor is: 25291 KW / h + 2972 KW / h = 28263 KW / h.

[0054] 3. Comparing Example 2 with Comparative Example 2, the power difference before and after adding the preheater is: 28851 KW / h - 28263 KW / h = 588 KW / h.

[0055] 4. Annual cost savings: 588 (KW / h) * 0.5 (yuan) * 8000 (hours) = 2.352 million yuan / h.

[0056] The present invention combines the air filter 1 at the inlet of the air compressor 2 with the preheater 7, adds a preheater 1 in front of the air filter 1 to form an integrated structure, heats the air with an annual average temperature of 9.9 °C to the intake temperature of the air compressor 2, which is 31 °C, with hot water at 95 °C, can effectively ensure that the air enters the air compressor 2 at a constant temperature, thus ensuring the air compressor 2 operates under high-efficiency and stable conditions. At the same time, the temperature of the compressed air rises to 161 °C and directly enters the reactor of the maleic anhydride device, avoiding the use of the heater 5 before the reactor and reducing the steam consumption for the heater 5.

Claims

1. An air filter, characterized in that: It comprises a box body, both ends of which are respectively provided with an air inlet and an air outlet, a preheater and a filter chamber are arranged inside the box body, and the preheater is close to the air inlet.

2. The air filter according to claim 1, characterized in that A muffler is arranged inside the box body, and the muffler is close to the air outlet; a service chamber is arranged between the preheater and the filter chamber; and a transition section is arranged between the filter chamber and the muffler.

3. The air filter according to claim 1, characterized in that A filter element is arranged in the filter chamber; a rainproof canopy is arranged outside the air inlet; a back-blowing device is arranged on the top of the filter chamber, and the back-blowing device is connected to a clean air source; a dust outlet is arranged at the bottom of the filter chamber; and a fan is also arranged at the bottom of the filter chamber.

4. The air filter according to claim 1 or 3, characterized in that: The filter chamber is also provided with a control cabinet, and the control cabinet is connected to the back-blowing device.

5. The air filter according to claim 1, characterized in that The preheater comprises a preheating unit, and the preheating unit comprises a fin tube and a fixing frame for fixing the fin tube.

6. The air filter according to claim 5, characterized in that The fin tube includes a base tube and fins, the fins are located outside the base tube, and the two ends of the base tube are a water inlet end and a water outlet end; the fixing frame includes a fixing plate, a fixing rod and a fastening diagonal brace, the fixing plate is located in the vertical direction, the fin tube part passes through the fixing plate, the fixing rod is located in the horizontal direction, the fixing plate and the fixing rod form a frame structure, and the side of the frame structure is provided with a fastening diagonal brace.

7. The air filter according to claim 5, characterized in that The preheating unit is single or multiple, and multiple preheating units are connected in parallel; the finned tube is single or multiple, and multiple finned tubes are connected in parallel; when there are multiple finned tubes, the water inlet ends of the multiple base tubes are connected to the water inlet through the water inlet header, and the water outlet ends of the multiple base tubes are connected to the water outlet through the water outlet header.

8. An air compressor, characterized in that: An air filter comprising the air filter of any one of claims 1 to 7, wherein an air outlet of the air filter is connected to an air inlet of an air compressor.

9. The air compressor according to claim 8, characterized in that: The air compressor is connected to the steam turbine and driven by the steam turbine; the air outlet of the air compressor is connected to the reactor of the maleic anhydride device.

10. The air compressor according to claim 9, characterized in that: The steam turbine is provided with a steam inlet and a steam outlet, wherein the steam inlet is connected to a high-pressure steam source, and the steam outlet is connected to a condenser.

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