Ultrahigh-precision filter for desulfurization liquid catalyst concentration on-line monitoring system

Abstract

The invention relates to an ultrahigh-precision filter for a desulfurization liquid catalyst concentration online monitoring system. The ultrahigh-precision filter comprises a filter shell, a multi-stage metal filter screen, a filter filler and an ultrafiltration membrane, one side of the upper part of the filter shell is provided with a liquid inlet connected with a desulfurization liquid inlet pipe, and the bottom is provided with a liquid outlet connected with a desulfurization liquid outlet pipe; the multiple stages of metal filter screens are sequentially arranged in the filter shell from outside to inside, and the sizes of filter holes are gradually reduced; the innermost metal filter screen is filled with the filter filler; and an ultrafiltration membrane is arranged at the bottom of the innermost metal filter screen. A five-stage gradient filtering structure is adopted, the filtering precision is gradually reduced to 0.45 m from 50 m, and the cleanliness requirement during online detection of the desulfurization liquid catalyst can be met; a backwashing regeneration function is realized, and the service life of the filter element is obviously prolonged; by adopting a full-corrosion-resistant material and a modular structure, the device can be compatible with broad-spectrum media such as a water phase, an oil phase, acid-base, an organic solvent and the like, and is low in maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of coking technology, and in particular to an ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid. Background Technology

[0002] Coke oven gas is a byproduct of the coking process and a valuable gaseous fuel. However, untreated raw coke oven gas contains various sulfides, primarily hydrogen sulfide (H2S) and small amounts of organic sulfur compounds (such as CS2 and COS). Without treatment, this can lead to serious problems such as environmental pollution, equipment corrosion, toxicity in chemical production, and compromised product quality. Therefore, coke oven desulfurization is an indispensable environmentally friendly and energy-saving process for modern coking enterprises.

[0003] The core of coking desulfurization is the removal of hydrogen sulfide. The mainstream process is wet desulfurization, which uses a liquid absorbent (desulfurization liquid) to come into countercurrent contact with the coal gas in the absorption tower to selectively absorb H2S.

[0004] The concentration of catalyst in the coking desulfurization liquid is the "control center" of the entire desulfurization system, directly, significantly, and interconnectedly affecting H2S removal efficiency, equipment corrosion rate, and operating costs. The core function of the catalyst is to accelerate the oxidation of H2S to elemental sulfur in the regeneration tower. When the catalyst concentration is too low, desulfurization efficiency decreases significantly, resulting in excessive H2S content after desulfurization, difficulty in sulfur foam flotation, and accelerated accumulation of byproduct salts within the system. Conversely, when the catalyst concentration is too high, desulfurization efficiency may decrease instead of increase, leading to intensified side reactions, increased solution viscosity, and even the risk of sulfur blockage.

[0005] The optimal range of catalyst concentration in desulfurization liquid is not fixed; it varies depending on factors such as catalyst type, gas load, H2S inlet concentration, and operating temperature. Therefore, process monitoring needs to be strengthened during production. By monitoring the catalyst concentration in the desulfurization liquid online, continuously, and accurately, catalyst can be added "on demand," ensuring the long-term stable, economical, and green operation of the desulfurization system.

[0006] There are many types of desulfurization catalysts (such as PDS, tannin, HPF, etc.), and their detection methods vary, but the basic principle is mostly spectrophotometry. This is based on the principle that the catalyst or its derivatives selectively absorb light at a specific wavelength, and that the absorbance is directly proportional to the concentration of the solution (following the Lambert-Beer Law). By measuring the absorbance and comparing it with a pre-plotted standard curve, the concentration of the catalyst in the sample can be calculated. However, desulfurization solutions usually contain sulfur foam and mechanical impurities. If these are directly introduced into the catalyst concentration detection system, it can lead to abnormal spectrophotometric absorbance, column blockage, or electrode contamination, causing the effective concentration of the catalyst to be calculated as either "falsely high" or "falsely low." Therefore, the desulfurization solution must be filtered before online detection of the catalyst concentration.

[0007] Currently, most liquid filters on the market are single-stage or two-stage filtration structures. When used for desulfurization liquid filtration in online monitoring systems for desulfurization catalyst concentration, the following problems exist: 1) The filtration accuracy is low, making it difficult to meet the high-precision (e.g., 5 microns) filtration requirements.

[0008] 2) Prone to clogging: Large particles of impurities can cause rapid clogging of the filter element during single-stage filtration, affecting the filter's service life.

[0009] 3) High maintenance costs, as the filter element usually needs to be replaced frequently, which increases the operating costs.

[0010] Therefore, developing a high-precision filter that can operate sustainably will be key to achieving accurate online detection of catalyst concentration in desulfurization liquid. Summary of the Invention

[0011] This invention provides an ultra-high precision filter for an online monitoring system of desulfurization liquid catalyst concentration. It adopts a five-stage gradient filtration structure, with the filtration precision decreasing from 50 micrometers to 0.45 micrometers in stages, which can meet the cleanliness requirements of online detection of desulfurization liquid catalyst. It has a backwashing regeneration function, which significantly extends the service life of the filter element. It adopts all corrosion-resistant materials and a modular structure, which can be compatible with a wide range of media such as aqueous phase, oil phase, acid and alkali, and organic solvents, and has low maintenance costs.

[0012] To achieve the above objectives, the present invention employs the following technical solution: An ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid includes a filter housing, multi-stage metal filter screens, filter filler, and an ultrafiltration membrane. The filter housing has an inlet on one side of its upper portion connected to a desulfurization liquid inlet pipe, and an outlet at its bottom connected to a desulfurization liquid outlet pipe. The multi-stage metal filter screens are arranged sequentially from the outside to the inside of the filter housing, with the pore size decreasing at each stage. The filter filler is placed in the innermost metal filter screen. An ultrafiltration membrane is located at the bottom of the innermost metal filter screen.

[0013] The multi-stage metal filter screen is coaxially arranged with the filter housing, and consists of a first-stage stainless steel filter screen, a second-stage stainless steel filter screen, and a third-stage stainless steel filter screen from the outside to the inside; wherein, the first-stage stainless steel filter screen has an aperture of 280-320 mesh, the second-stage stainless steel filter screen has an aperture of 750-850 mesh, and the third-stage stainless steel filter screen has an aperture of 2000-3000 mesh; the filter filler is filled in the third-stage stainless steel filter screen.

[0014] The three-stage stainless steel filter screen is equipped with a flow guide groove.

[0015] The filter filler is polytetrafluoroethylene (PTFE) filler with a porosity ≥80% and a filtration accuracy of 1µm.

[0016] The ultrafiltration membrane is a polymer ultrafiltration membrane with a filtration accuracy of 0.45µm.

[0017] The filter housing is made of stainless steel; the filter housing is connected to the desulfurization liquid inlet pipe via an inlet pipe flange and to the desulfurization liquid outlet pipe via an outlet pipe flange; both the inlet pipe flange and the outlet pipe flange are quick-release flanges.

[0018] The bottom of the filter housing is provided with an upper mounting flange and a lower mounting flange; the bottom end of the filter housing, the bottom end of the primary stainless steel filter screen, and the bottom end of the secondary stainless steel filter screen are respectively welded and fixed to the upper mounting flange; the bottom end of the tertiary stainless steel filter screen is welded and fixed to the lower mounting flange; the lower mounting flange and the upper mounting flange are connected by bolts, and a sealing gasket is provided at the connection between the upper mounting flange and the lower mounting flange; flow channel holes are respectively opened in the middle of the upper mounting flange and the middle of the lower mounting flange, and the ultrafiltration membrane is placed at the top of the corresponding flow channel hole of the lower mounting flange.

[0019] A backwashing medium inlet pipe is provided on one side of the lower mounting flange, which is connected to the flow channel hole of the lower mounting flange through the backwashing medium flow channel, and the height of the backwashing medium flow channel is lower than the installation height of the ultrafiltration membrane; a backwashing medium outlet pipe is provided on the lower side of the filter housing.

[0020] The backwash medium inlet pipe is connected to a water supply pipe or a compressed air pipe.

[0021] The ultrafiltration membrane is a polymer ultrafiltration membrane.

[0022] Compared with the prior art, the beneficial effects of the present invention are: 1) A five-stage gradient filtration structure is adopted. The desulfurization liquid first passes through three layers of metal filter screens, with the filtration accuracy decreasing from 50μm to 5μm in stages, to filter out coarse, medium and fine particles in the desulfurization liquid; then it passes through a polytetrafluoroethylene (PTFE) deep filter layer with flow guide grooves to retain colloids and oxides larger than 1μm, while maintaining a low pressure drop; finally, it passes through a polymer ultrafiltration membrane with a filtration accuracy of 0.45μm to ensure a high-precision filtration effect and fully meet the cleanliness requirements of the desulfurization liquid catalyst during online detection. 2) The five-stage gradient filtration structure disperses the load and has a backwashing regeneration function, significantly extending the service life of the filter element; 3) It adopts all corrosion-resistant materials and modular structure, which can be compatible with a wide range of media such as water phase, oil phase, acid and alkali, organic solvents, and has low maintenance cost. Attached Figure Description

[0023] Figure 1 This is an external view of the ultra-high precision filter described in this invention.

[0024] Figure 2This is a front cross-sectional view of the ultra-high precision filter described in this invention.

[0025] Figure 3 This is an exploded view of the ultra-high precision filter described in this invention.

[0026] In the diagram: 1-Filter housing; 2-First-stage stainless steel filter screen; 3-Second-stage stainless steel filter screen; 4-Third-stage stainless steel filter screen; 5-Filter packing material; 6-Ultrafiltration membrane; 7-Upper mounting flange; 8-Lower mounting flange; 9-Outlet pipe connection flange; 10-Backwash medium inlet pipe; 11-Backwash medium outlet pipe; 12-Inlet pipe connection flange; 13-Sealing gasket. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings: like Figures 1-3 As shown, the ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to the present invention includes a filter housing 1, multi-stage metal filter screens, filter filler 5, and an ultrafiltration membrane 6. The filter housing 1 has an inlet on one side of the upper part connected to the desulfurization liquid inlet pipe, and an outlet at the bottom connected to the desulfurization liquid outlet pipe. The multi-stage metal filter screens are arranged sequentially from the outside to the inside inside the filter housing 1, and the filter pore size decreases step by step. The filter filler 5 is filled in the innermost metal filter screen. The ultrafiltration membrane 6 is located at the bottom of the innermost metal filter screen.

[0028] The multi-stage metal filter screen is coaxially arranged with the filter housing 1, and from the outside to the inside are a first-stage stainless steel filter screen 2, a second-stage stainless steel filter screen 3, and a third-stage stainless steel filter screen 4; wherein, the pore size of the first-stage stainless steel filter screen 2 is 280-320 mesh, the pore size of the second-stage stainless steel filter screen 3 is 750-850 mesh, and the pore size of the third-stage stainless steel filter screen 4 is 2000-3000 mesh; the filter filler 5 is filled in the third-stage stainless steel filter screen 4.

[0029] The three-stage stainless steel filter screen 4 is equipped with a flow guide groove.

[0030] The filter filler 5 is a polytetrafluoroethylene (PTFE) filler with a porosity ≥80% and a filtration accuracy of 5µm.

[0031] The ultrafiltration membrane 6 is a polymer ultrafiltration membrane with a filtration accuracy of 0.45µm.

[0032] The filter housing 1 is made of stainless steel (preferably 304 or 316L stainless steel); the filter housing 1 is connected to the desulfurization liquid inlet pipe through the inlet pipe connecting flange 12, and to the desulfurization liquid outlet pipe through the outlet pipe connecting flange 9; both the inlet pipe connecting flange 12 and the outlet pipe connecting flange 9 are quick-release flanges.

[0033] The bottom of the filter housing 1 is provided with an upper mounting flange 7 and a lower mounting flange 8; the bottom end of the filter housing 1, the bottom end of the primary stainless steel filter screen 2, and the bottom end of the secondary stainless steel filter screen 3 are respectively welded and fixed to the upper mounting flange 7; the bottom end of the tertiary stainless steel filter screen 4 is welded and fixed to the lower mounting flange 8; the lower mounting flange 8 and the upper mounting flange 7 are connected by bolts, and a sealing gasket 13 is provided at the connection between the upper mounting flange 7 and the lower mounting flange 8; flow channel holes are respectively opened in the middle of the upper mounting flange 7 and the middle of the lower mounting flange 8, and the ultrafiltration membrane 6 is located at the top of the corresponding flow channel hole of the lower mounting flange 8.

[0034] A backwashing medium inlet pipe 10 is provided on one side of the lower mounting flange 8, which is connected to the flow channel hole of the lower mounting flange 8 through the backwashing medium flow channel, and the height of the backwashing medium flow channel is lower than the installation height of the ultrafiltration membrane 6; a backwashing medium outlet pipe 11 is provided on one side of the lower part of the filter housing 1.

[0035] The backwash medium inlet pipe 10 is connected to a water supply pipe or a compressed air pipe. The backwash medium inlet pipe 10 can be equipped with a solenoid valve or a manual valve to realize automatic or manual backwashing.

[0036] The ultrafiltration membrane 6 is a polymer ultrafiltration membrane.

[0037] The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid, as described in this invention, preferably employs a five-stage gradient filtration structure. Along the flow direction of the desulfurization liquid, three layers of stainless steel filter screens are first installed, with pore sizes gradually decreasing from 50 μm to 5 μm, filtering out coarse, medium, and fine particles in the desulfurization liquid. A filter packing material 5 (preferably polytetrafluoroethylene) is placed within the three-stage stainless steel filter screen 4 as an adsorption layer, capable of retaining colloids and oxides larger than 1 μm. A flow guide groove is provided within the three-stage stainless steel filter screen 4 to guide the flow direction of the desulfurization liquid, increase the contact area between the desulfurization liquid and the filter packing material 5, and provide support for the filter packing material 5, reducing pressure loss. At the very end of the liquid flow, an ultrafiltration membrane (preferably a polymer ultrafiltration membrane) with a filtration precision of 0.45 μm is installed to ensure a high-precision filtration effect.

[0038] The present invention discloses an ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid. All filter components are made of acid- and alkali-resistant and organic solvent-resistant materials, and adopt a modular structure. Each module is independently packaged and can be regenerated through backwashing. The backwashing medium can be clean water or low-pressure compressed air (0.2-0.4 MPa), and the backwashing should continue for 30-60 seconds, or until the effluent is clear.

[0039] Compared to existing single-stage or two-stage filters, the ultra-high precision filter of this invention achieves a filtration accuracy of 0.45μm and exhibits a gradient load distribution, avoiding excessive single-stage load and thus significantly extending the filter's service life. Its modular, quick-release design facilitates maintenance and provides a stable supply of desulfurization liquid meeting process cleanliness requirements for the online catalyst concentration monitoring system.

[0040] During the use of the ultra-high precision filter for the online monitoring system of desulfurization liquid catalyst concentration described in this invention, the filter filler 5 and ultrafiltration membrane 6 are replaced every 10 to 30 days (adjusted according to operating conditions). The first- to third-stage stainless steel filter screens can be disassembled, mechanically cleaned, and then reused.

[0041] The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid described in this invention is suitable for desulfurization liquid with a pH value of 1 to 14 and can withstand temperatures ≤80℃.

[0042] The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid described in this invention requires the system to be shut down during backwashing to avoid damage to the filter element from high-pressure impact.

[0043] To more intuitively illustrate the present invention, the embodiments of the present invention will be further described in conjunction with the examples. The following examples are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention, including simple variations or equivalent substitutions, are all within the scope of protection of the present invention.

[0044]

Example 1

[0045] 2. First and Second Stage Filter Components: The first-stage stainless steel filter screen 2 has a pore size of 300 mesh (approximately 50µm) and is used to intercept large particulate impurities; the second-stage stainless steel filter screen 3 has a pore size of 800 mesh and is used to filter medium-sized particulate impurities. The bottoms of the second-stage stainless steel filter screen 3 and the first-stage stainless steel filter screen 2 are reliably welded to the upper mounting flange 7.

[0046] 3. Third-stage filter element: The third-stage stainless steel filter screen 4 has a pore size of 2500 mesh (approximately 5µm) and is used to intercept particles larger than 5µm. The bottom of the third-stage stainless steel filter screen 4 is reliably welded to the lower mounting flange 8.

[0047] 4. Fourth-stage filter element: The third-stage stainless steel filter screen 4 is filled with polytetrafluoroethylene (PTFE) as an adsorption layer, and a guide groove is set in the third-stage stainless steel filter screen 4 to guide the flow direction of the desulfurization liquid, increase the contact area between the desulfurization liquid and the PTFE adsorption layer, provide support for the PTFE adsorption layer, and reduce pressure loss. The fourth-stage filter element is used to adsorb colloids, oxides, etc., and the filtration accuracy is 1µm.

[0048] 5. Fifth stage filter element: Install a polymer ultrafiltration membrane at the top of the flow channel hole of the lower mounting flange 8 to ensure a final filtration accuracy of 0.45µm.

[0049] 6. Sealing and Connections: A polytetrafluoroethylene (PTFE) gasket is used as a sealing element between the upper mounting flange 7 and the lower mounting flange 8. It is resistant to acid and alkali corrosion and can withstand pressures of not less than 1 MPa, ensuring reliable sealing. The inlet pipe connection flange 12 and the outlet pipe connection flange 9 are adapted to pipelines under different operating conditions.

[0050] 7. Backwashing assembly: A backwashing medium inlet pipe 10 is provided on one side of the lower mounting flange 8, and a backwashing medium outlet pipe 11 is provided on the lower side of the filter housing 1. Automatic backwashing is achieved through a solenoid valve.

[0051] The ultra-high precision filter assembled in this embodiment is used in the online monitoring system for desulfurization liquid catalyst concentration, and can meet the cleanliness requirements of the desulfurization liquid for the online detection system of desulfurization liquid catalyst.

[0052]

Example 2

[0053] 2. Backwashing: Clean water is used as the backwashing medium. The water enters the ultra-high precision filter from the desulfurization liquid outlet end in reverse and cleans the following in sequence: polymer ultrafiltration membrane → PTFE adsorption layer → three-stage stainless steel filter screen 4 → two-stage stainless steel filter screen 3 → one-stage stainless steel filter screen 1. The wastewater after backwashing is discharged from the backwashing medium outlet pipe 11. After 60 seconds of continuous rinsing, the water becomes clear and the backwashing stops.

[0054] 3. Replace the polymer ultrafiltration membrane.

[0055] 4. Restore system operation: Close the drain valve on the backwash medium outlet pipe 11 and the control valve on the backwash medium inlet pipe 10, open the control valve on the desulfurization liquid inlet pipe, and restart the filtration process.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid, characterized in that, The filter includes a filter housing, multi-stage metal filter screens, filter filler, and an ultrafiltration membrane. The filter housing has an inlet on one side of the upper part connected to the desulfurization liquid inlet pipe and an outlet at the bottom connected to the desulfurization liquid outlet pipe. The multi-stage metal filter screens are arranged sequentially from the outside to the inside inside the filter housing, with the filter pore size decreasing at each stage. The filter filler is filled in the innermost metal filter screen. An ultrafiltration membrane is located at the bottom of the innermost metal filter screen.

2. The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 1, characterized in that, The multi-stage metal filter screen is coaxially arranged with the filter housing, and consists of a first-stage stainless steel filter screen, a second-stage stainless steel filter screen, and a third-stage stainless steel filter screen from the outside to the inside; wherein, the first-stage stainless steel filter screen has an aperture of 280-320 mesh, the second-stage stainless steel filter screen has an aperture of 750-850 mesh, and the third-stage stainless steel filter screen has an aperture of 2000-3000 mesh; the filter filler is filled in the third-stage stainless steel filter screen.

3. The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 2, characterized in that, The three-stage stainless steel filter screen is equipped with a flow guide groove.

4. The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 1, characterized in that, The filter filler is polytetrafluoroethylene (PTFE) filler with a porosity ≥80% and a filtration accuracy of 1µm.

5. The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 1, characterized in that, The ultrafiltration membrane is a polymer ultrafiltration membrane with a filtration accuracy of 0.45µm.

6. The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 1, characterized in that, The filter housing is made of stainless steel; the filter housing is connected to the desulfurization liquid inlet pipe via an inlet pipe flange and to the desulfurization liquid outlet pipe via an outlet pipe flange; both the inlet pipe flange and the outlet pipe flange are quick-release flanges.

7. The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 2, characterized in that, The bottom of the filter housing is provided with an upper mounting flange and a lower mounting flange; the bottom end of the filter housing, the bottom end of the primary stainless steel filter screen, and the bottom end of the secondary stainless steel filter screen are respectively welded and fixed to the upper mounting flange; the bottom end of the tertiary stainless steel filter screen is welded and fixed to the lower mounting flange; the lower mounting flange and the upper mounting flange are connected by bolts, and a sealing gasket is provided at the connection between the upper mounting flange and the lower mounting flange; flow channel holes are respectively opened in the middle of the upper mounting flange and the middle of the lower mounting flange, and the ultrafiltration membrane is placed at the top of the corresponding flow channel hole of the lower mounting flange.

8. The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 7, characterized in that, A backwashing medium inlet pipe is provided on one side of the lower mounting flange, which is connected to the flow channel hole of the lower mounting flange through the backwashing medium flow channel, and the height of the backwashing medium flow channel is lower than the installation height of the ultrafiltration membrane; a backwashing medium outlet pipe is provided on the lower side of the filter housing.

9. The ultra-high precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 8, characterized in that, The backwash medium inlet pipe is connected to a water supply pipe or a compressed air pipe.

10. A high-precision filter for an online monitoring system of catalyst concentration in desulfurization liquid according to claim 1, 5, or 7, characterized in that, The ultrafiltration membrane is a polymer ultrafiltration membrane.

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