Washing system of methanol-to-olefin device

Abstract

The utility model relates to the technical field of methanol-to-olefin equipment, in particular to a washing system of a methanol-to-olefin device. According to the specific technical scheme, the water washing system of the methanol-to-olefin device comprises a water washing tower, a plurality of filtration and adsorption devices are arranged at the bottom of the water washing tower in parallel, each filtration and adsorption device comprises a filter cartridge, the two ends of each filter cartridge are connected with a water inlet pipe and a water outlet pipe respectively, and the water inlet pipe is connected with the water washing tower. The water inlet pipes and the water outlet pipes are respectively communicated with a water inlet header pipe and a water outlet header pipe, the water inlet header pipe is communicated with a water washing tower, and the water outlet header pipe is communicated with a sewage stripping tower; and a plurality of layers of filter materials are arranged in the filter cartridge. The utility model solves the problems that the pressure drop of the water washing tower is increased, the heat exchange efficiency of the water washing water-cooling heat exchange equipment is reduced and the like due to the fact that dirt substances such as fine catalyst particles and oil wax entrained in the product gas are attached and deposited in the tower tray of the water washing tower and the pipeline of the cooling heat exchange equipment (cooling heat exchange equipment).

Description

Technical Field

[0001] This utility model relates to the technical field of methanol-to-olefins equipment, specifically to a water washing system for a methanol-to-olefins unit. Background Technology

[0002] The MTO unit uses crude or refined methanol as feedstock, reacting it with a catalyst to produce low-carbon olefin product gas. This product gas is then washed and cooled in a quench water washing system to remove the catalyst and water before being sent to the olefin separation unit for purification of ethylene, propylene, C4, and other products. While producing light olefin products, the MTO process also generates 56% water as a byproduct and produces oily substances.

[0003] The water scrubbing tower in an MTO unit is a crucial component of the methanol-to-olefins (MTO) industrial plant. Its main function is to lower the temperature of the reactant gas and condense the water, while further washing and removing fine catalyst particles entrained in the reactant gas and oily or waxy substances from the water scrubbing system. Through the water scrubbing tower, the purity and stability of the reactant gas are ensured, thereby guaranteeing the safe, stable, and long-term operation of the entire unit.

[0004] However, in actual operation, the water washing system of the MTO unit may encounter blockage problems. This is mainly because fine catalyst particles, oily and waxy substances and other contaminants carried in the product gas adhere and deposit in the trays of the water washing tower and the pipelines of the cooling heat exchange equipment, resulting in problems such as increased pressure drop in the water washing tower and decreased heat exchange efficiency of the water washing cooling heat exchange equipment.

[0005] To address the wax buildup problem in the MTO water system, various technical measures were implemented, such as installing an oil separator in the water system to separate oil, adding an oil remover before the wastewater stripping tower, installing an oil-water separation device in the water circulation process, adding demulsifiers, offline cleaning of heat exchangers and air coolers, online steaming towers, online injection of extractant for washing, online cleaning of tower trays, and adding scale inhibitors and dispersants. However, the results were not satisfactory.

[0006] Setting up oil separators, oil removers, and oil-water separators can reduce the amount of oil entering the wastewater stripping tower to some extent, but they cannot prevent oil from condensing in the wastewater stripping system and clogging equipment and pipelines. Oil-water separation can reduce the accumulation of wax in the water system, but it cannot fundamentally solve the waxing problem of MTO. Offline cleaning of heat exchangers and air coolers, as well as online cleaning of trays, can alleviate the accumulation of oil and remove wax, but it increases maintenance costs, and frequent load reduction can seriously affect the long-term operation of the unit. Adding demulsifiers can promote oil-water separation in the water system, but it will affect the stripping effect of the downstream wastewater stripping tower. Online injection of extractant washing can alleviate waxing in the water system, but the cost of the extractant is not small. Adding dispersants can alleviate catalyst clogging, but the dispersed wax will still precipitate in heat exchangers, trays, and pipelines at low temperatures. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this utility model provides a water washing system for a methanol-to-olefins (MTO) plant, which solves the problems of fine catalyst particles, oily and waxy substances, and other contaminants carried in the product gas adhering and depositing in the trays of the water washing tower and the pipelines of the cooling heat exchange equipment (cooling exchange equipment), leading to increased pressure drop in the water washing tower and decreased heat exchange efficiency of the water washing cooling exchange equipment.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] This utility model discloses a water washing system for a methanol-to-olefins (MTO) plant, including a water washing tower. A filtration and adsorption device is installed at the bottom of the water washing tower. Multiple filtration and adsorption devices are arranged in parallel. Each filtration and adsorption device includes a filter cylinder. The two ends of the filter cylinder are respectively connected to an inlet pipe and an outlet pipe. The multiple inlet pipes and outlet pipes are respectively connected to a main inlet pipe and a main outlet pipe. The main inlet pipe is connected to the water washing tower, and the main outlet pipe is connected to a wastewater stripping tower. Multiple layers of filter material are installed inside the filter cylinder.

[0010] Preferably, each of the water inlet pipes and water outlet pipes is equipped with a first valve, and the main water inlet pipe and / or the main water outlet pipe is equipped with a water washing tower bottom pump.

[0011] Preferably, the filter material is one or more of porous diatomaceous earth, scale inhibitor, sodium sulfate, wollastonite, and bentonite; each material is loaded into a mesh cylinder made of filter screen and placed inside the filter cylinder along the axial direction of the filter cylinder.

[0012] Preferably, the filtration and adsorption device is equipped with a backwashing device, which includes a reagent inlet pipe connected to each filter cartridge, the reagent inlet pipe being connected to a reagent main pipe, and the reagent main pipe being equipped with a second valve, a pump, and a reagent tank; the other end of each filter cartridge is connected to a flushing outlet pipe, the flushing outlet pipe being connected to a flushing main pipe, the flushing main pipe being connected to the reagent main pipe through a pipeline, the pipeline being equipped with a circulation pump, and the pipelines located at both ends of the circulation pump being equipped with third valves respectively.

[0013] Preferably, the reagent inlet tube is located at one end of the filter cartridge connected to the water outlet tube, and the rinsing outlet tube is located at one end of the filter cartridge connected to the water inlet tube.

[0014] Preferably, the filter cylinder includes a first filter tank and a second filter tank that are fastened together. The inlet pipe and the outlet pipe are connected to the two ends of the first filter tank. A filter screen with an open end and an arc shape is provided in the second filter tank. The edge of the filter screen extends into the second filter tank and forms a column shape with the second filter tank. The open end of the filter screen is oriented towards the inlet pipe.

[0015] Preferably, the filter screen is adapted to the first filter tank so that the filter screen can be completely placed in the first filter tank and fit against the inner wall of the first filter tank.

[0016] Preferably, a sealing ring is provided at the end face of the opening of the first filter tank, and a sealing groove corresponding to and adapted to the sealing ring is provided at the end face of the opening of the second filter tank. The first filter tank and the second filter tank are fixed by clamps.

[0017] Preferably, the first filter tank and the second filter tank are respectively provided with arc-shaped grooves on their side walls, and the clamp is placed in the arc-shaped grooves to lock and fix the first filter tank and the second filter tank; multiple arc-shaped grooves are respectively provided along the axial direction of the first filter tank and the second filter tank.

[0018] Preferably, the inlet pipe and the outlet pipe are rotatably connected to the first filter tank via bearings, the rinsing outlet pipe is connected to the inlet pipe, and the reagent inlet pipe is connected to the outlet pipe.

[0019] This utility model has the following beneficial effects:

[0020] This invention utilizes an adsorption filtration device installed at the bottom outlet of the water washing tower to efficiently filter and adsorb fine catalyst particles, oily and waxy substances, and other contaminants. Furthermore, the multiple adsorption filtration devices can be individually disassembled, replaced, backwashed, and activated without affecting the continuous production of olefins. Additionally, this invention removes oily and waxy oligomers by adding xylene or diesel fuel for backwashing. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the structure of the filtration and adsorption device of this utility model;

[0022] Figure 2 for Figure 1 View from AA direction;

[0023] Figure 3 This is a schematic diagram of the backwashing device.

[0024] Figure 4 This is a schematic diagram of the first filter tank structure;

[0025] Figure 5 This is a schematic diagram of the second filter tank structure;

[0026] In the diagram: 1. Inlet pipe; 2. Outlet pipe; 3. Main inlet pipe; 4. Main outlet pipe; 5. First valve; 6. Reagent inlet pipe; 7. Main reagent pipe; 8. Second valve; 9. Pump; 10. Reagent tank; 11. Rinse outlet pipe; 12. Rinse main pipe; 13. Pipe; 14. Circulation pump; 15. Third valve; 16. First filter tank; 17. Second filter tank; 18. Filter screen; 19. Sealing ring; 20. Sealing groove; 21. Clamp; 22. Arc groove. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] Unless otherwise specified, the technical means used in the implementation examples are conventional means well known to those skilled in the art.

[0029] refer to Figures 1-5 This utility model discloses a water washing system for a methanol-to-olefins (MTO) plant, including a water washing tower. A filtration and adsorption device is installed at the bottom of the water washing tower to quickly remove fine catalyst particles, oily or waxy substances, and other contaminants carried in the product gas, thereby preventing contaminant deposition in the pipeline. Multiple filtration and adsorption devices are arranged in parallel, and each device is detachable and can be added or removed as needed. Each filtration and adsorption device includes a filter cylinder, with an inlet pipe 1 and an outlet pipe 2 connected to its two ends. Multiple inlet pipes 1 and outlet pipes 2 are connected to a main inlet pipe 3 and a main outlet pipe 4, respectively. The main inlet pipe 3 is connected to the water washing tower, and the main outlet pipe 4 is connected to a wastewater stripping tower. The filter cylinder contains multiple layers of filter material, with each layer containing the same, different, or mixed types of filter material. Both the water washing tower and the wastewater stripping tower are existing technologies.

[0030] Furthermore, each of the inlet pipe 1 and outlet pipe 2 is equipped with a first valve 5, and the main inlet pipe 3 and / or the main outlet pipe 4 is equipped with a water washing tower bottom pump. The pumps draw water from the water washing tower to the filtration and adsorption device, and / or draw the filtered water to the wastewater stripping tower.

[0031] Furthermore, the filter material is one or more of porous diatomaceous earth, scale inhibitor, sodium sulfate, wollastonite, and bentonite, which can be formulated according to actual needs; each material is loaded into a mesh cylinder made of filter screen and placed in the filter cylinder along the axial direction of the filter cylinder. The materials in each mesh cylinder can be the same, different, or a mixture of multiple materials. By setting the mesh cylinder, the material can be effectively prevented from scattering, and it is also easy to replace.

[0032] Furthermore, the filtration and adsorption device is equipped with a backwashing device, which includes a reagent inlet pipe 6 connected to each filter cartridge. The reagent inlet pipe 6 is connected to a reagent main pipe 7, and the reagent main pipe 7 is equipped with a second valve 8, a pump 9, and a reagent tank 10. The other end of each filter cartridge is connected to a flushing outlet pipe 11, which is connected to a flushing main pipe 12. The flushing main pipe 12 is connected to the reagent main pipe 7 via a pipe 13, and a circulation pump 14 is installed on the pipe 13. Third valves 15 are installed on the pipes 13 at both ends of the circulation pump 14. It should be noted that the reagent tank can be filled with xylene or diesel oil for backwashing to remove oily and waxy oligomers. Valves can be installed on each flushing outlet pipe and reagent inlet pipe as needed to individually control whether reagent is introduced into each filter cartridge. Alternatively, scale inhibitors and dispersants (polyaspartic acid, maleic acid acrylic acid copolymer, organophosphonate reverse osmosis scale inhibitors) can be added to the reaction gas to flocculate and inhibit the scale formation of waxy oil, thereby preventing the oligomers of waxy oil from adhering and accumulating on the inner wall of the pipe.

[0033] Furthermore, the reagent inlet pipe 6 is located at one end of the filter cylinder connected to the water outlet pipe 2, and the rinsing outlet pipe 11 is located at one end of the filter cylinder connected to the water inlet pipe 1.

[0034] Furthermore, the filter cartridge includes a first filter tank 16 and a second filter tank 17 that are fastened together. The inlet pipe 1 and the outlet pipe 2 are connected to the two ends of the first filter tank 16. A filter screen 18 with an open end and an arc shape is disposed inside the second filter tank 17. The edge of the filter screen 18 extends into and is fixed within the second filter tank 17, forming a hollow cylindrical shape with the second filter tank 17 to accommodate adsorbent material. The shape of the filter cylinder containing the adsorbent material is adapted to this cylindrical shape. The open end of the filter screen 18 faces the inlet pipe 1, allowing water to enter the second filter tank from the open end of the filter screen. This also prevents the adsorbent material from spilling when the second filter tank is removed to replace it; specifically, the open end of the filter screen faces upwards when the second filter tank is removed. A handle can be provided on the side wall of the second filter tank as needed for easy removal.

[0035] Furthermore, the filter screen 18 is adapted to the first filter tank 16 so that the filter screen 18 can be completely placed in the first filter tank 16 and fit against the inner wall of the first filter tank 16, avoiding large gaps between the filter screen and the first filter tank.

[0036] Furthermore, to achieve a seal between the first and second filter tanks and prevent water leakage, a sealing ring 19 is provided at the end face of the opening of the first filter tank 16, and a sealing groove 20 corresponding to and fitting the sealing ring 19 is provided at the end face of the opening of the second filter tank 17. The first filter tank 16 and the second filter tank 17 are fixed together by a clamp 21. When the first and second filter tanks are combined, the sealing ring is inserted into the sealing groove with an interference fit, and then locked and fixed by the clamp.

[0037] Furthermore, to prevent the clamps from loosening or shifting when fixing the first and second filter tanks, arc-shaped grooves 22 are respectively provided on the side walls of the first filter tank 16 and the second filter tank 17. The clamps 21 are placed in the arc-shaped grooves 22 to lock and fix the first filter tank 16 and the second filter tank 17. Multiple arc-shaped grooves 22 are provided along the axial direction of the first filter tank 16 and the second filter tank 17. It should be noted that the arc-shaped groove is composed of two corresponding arc-shaped strips, that is, the gap between the two arc-shaped strips is the arc-shaped groove. The clamps are located in the arc-shaped grooves and play a limiting role. The locking nut and hinge of the clamps are located in the gap between the first and second filter tanks, so that the first and second filter tanks can be separated after the clamps are loosened.

[0038] Furthermore, to secure the clamp within the arc-shaped groove, corresponding pin holes are provided on the two arc-shaped strips. Pins are inserted into these pin holes to confine the clamp within the arc-shaped groove. The number of pins can be adjusted as needed. Meanwhile, pin holes may not be provided on the second filter groove.

[0039] Furthermore, after the second filter tank is removed, in order to pour out the water remaining in the first filter tank, the inlet pipe 1 and the outlet pipe 2 are rotatably connected to the first filter tank 16 via bearings, so that the water can be poured out by rotating the first filter tank. At this time, the flushing outlet pipe 11 is connected to the inlet pipe 1, and the reagent inlet pipe 6 is connected to the outlet pipe 2, to prevent the flushing outlet pipe and the reagent inlet pipe from affecting the rotation of the first filter tank.

[0040] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model.

[0041] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A water washing system of a methanol to olefins plant, comprising a water washing column, characterized in that: The bottom of the water washing tower is provided with filter adsorption devices arranged in parallel, each of which comprises a filter cylinder, the two ends of which are connected with water inlet pipes (1) and water outlet pipes (2) respectively, a plurality of the water inlet pipes (1) and the water outlet pipes (2) are communicated with a water inlet main pipe (3) and a water outlet main pipe (4) respectively, the water inlet main pipe (3) is communicated with the water washing tower, and the water outlet main pipe (4) is communicated with a waste water stripping tower; a plurality of layers of filter materials are arranged in the filter cylinder.

2. The methanol to olefins device water washing system according to claim 1, characterized in that: First valves (5) are arranged on each of the water inlet pipes (1) and the water outlet pipes (2), and a water washing tower bottom pump is arranged on the water inlet main pipe (3) and / or the water outlet main pipe (4).

3. The methanol to olefins device water washing system according to claim 1, characterized in that: The filter materials are one or more of porous diatomite, scale inhibitor, anhydrous sodium sulfate, wollastonite and bentonite; each of the materials is loaded into a mesh cylinder formed by a filter screen and is arranged in the filter cylinder in an axial direction.

4. The methanol to olefins device water washing system according to claim 1, characterized in that: A reverse flushing device is arranged on the filter adsorption device, the reverse flushing device comprises reagent inlet pipes (6) communicated with the filter cylinders respectively, the reagent inlet pipes (6) are communicated with a reagent main pipe (7), the reagent main pipe (7) is provided with a second valve (8), a pump (9) and a reagent tank (10), one end of each of the filter cylinders is connected with a flushing outlet pipe (11), the flushing outlet pipe (11) is communicated with a flushing main pipe (12), the flushing main pipe (12) is communicated with the reagent main pipe (7) through a pipeline (13), the pipeline (13) is provided with a circulating pump (14), and the pipeline (13) located at the two ends of the circulating pump (14) is provided with third valves (15) respectively.

5. The methanol to olefins device water washing system according to claim 4, characterized in that: The reagent inlet pipes (6) are arranged at one end of the filter cylinder connected with the water outlet pipes (2), and the flushing outlet pipes (11) are arranged at one end of the filter cylinder connected with the water inlet pipes (1).

6. The methanol to olefins device water washing system according to claim 4, characterized in that: The filter cylinder comprises a first filter groove (16) and a second filter groove (17) fixed by buckling, the water inlet pipes (1) and the water outlet pipes (2) are connected at the two ends of the first filter groove (16), the second filter groove (17) is provided with an arc-shaped filter screen (18) with an open end, the edge of the filter screen (18) extends into the second filter groove (17) to form a cylinder with the second filter groove (17), and the open end of the filter screen (18) is arranged towards the water inlet pipes (1).

7. The methanol to olefins device water washing system according to claim 6, characterized in that: The filter screen (18) is adapted to the first filter groove (16) so that the filter screen (18) can be completely arranged in the first filter groove (16) and abut the inner wall of the first filter groove (16).

8. The methanol to olefins device water washing system according to claim 6, characterized in that: A sealing ring (19) is arranged at the end face of the opening of the first filter groove (16), a sealing groove (20) corresponding to and adapted to the sealing ring (19) is arranged at the end face of the opening of the second filter groove (17), and the first filter groove (16) and the second filter groove (17) are fixed by a clamp (21).

9. The methanol to olefins device water washing system according to claim 6, characterized in that: Corresponding arc grooves (22) are respectively arranged on the side walls of the first filter tank (16) and the second filter tank (17), the clamps (21) are arranged in the arc grooves (22) to lock and fix the first filter tank (16) and the second filter tank (17); the arc grooves (22) are respectively provided with a plurality of arc grooves along the axial direction of the first filter tank (16) and the second filter tank (17).

10. The methanol to olefins device water washing system according to claim 6, characterized in that: The water inlet pipe (1) and the water outlet pipe (2) are rotatably connected with the first filter tank (16) through bearings, the flushing outlet pipe (11) is communicated with the water inlet pipe (1), and the reagent inlet pipe (6) is communicated with the water outlet pipe (2).

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