Washing system of methanol-to-olefin device

Abstract

The invention 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. The invention 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 substances entrained in the product gas are attached and deposited in a tower tray of the water washing tower and a pipeline of the cooling heat exchange equipment (cooling heat exchange equipment).

Description

Technical Field

[0001] The invention relates to the technical field of methanol to olefins equipment, and in particular to a water washing system of a methanol to olefins device. Background Art

[0002] The MTO unit uses crude methanol or refined methanol as raw material, and generates light olefin product gas through the action of catalysts. The product gas is washed and cooled in the quench water washing system, and after the catalyst and water are removed, it is sent to the olefin separation unit for purification of ethylene, propylene, C4 and other products. While the MTO process generates light olefin products, it also produces 56% water as a by-product and oil substances.

[0003] The water scrubber of the MTO unit is an important component of the methanol to olefins (MTO) industrial unit. Its main function is to reduce the temperature of the reaction gas and condense water, while further washing and removing the fine catalyst particles entrained in the reaction gas and removing the oily waxy substances in the water washing system. Through the function of the water scrubber, the purity and stability of the reaction gas can be guaranteed, thereby ensuring 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 the fine catalyst particles, oil wax and other dirt substances carried in the product gas are attached and deposited in the water washing tower trays and cooling heat exchange equipment (cold exchange equipment) pipelines, resulting in increased pressure drop in the water washing tower and decreased heat exchange efficiency of the water washing water cooling exchange equipment.

[0005] In order to solve the wax deposition problem in the MTO water system, a variety of technical measures have been taken, such as setting up an oil separator in the water system to separate oil, adding an oil remover before the sewage stripping tower, installing an oil-water separation device in the water circulation process of the water system, adding demulsifiers, cleaning heat exchangers and air coolers offline, online steam towers, online injection of extractants for washing, online cleaning of tower plates, adding scale inhibitors and dispersants, etc. However, the results were not ideal.

[0006] The installation of oil separators, oil removers, and oil-water separation devices can reduce the amount of oil entering the sewage stripping tower to a certain extent, but it cannot prevent the oil from condensing in the sewage stripping system and thus clogging the equipment pipelines; oil-water separation can reduce the accumulation of waxy substances in the water system, but it cannot fundamentally solve the MTO waxing problem; offline cleaning of heat exchangers and air coolers, and online cleaning of tower plates can alleviate the accumulation of oily substances and clean out the waxy substances, but it increases the inspection and maintenance costs, and frequent load reduction treatments will also seriously affect the long-term operation of the device; adding demulsifiers can promote oil-water separation in the water system, which will affect the stripping effect of the downstream sewage stripping tower; online injection of extractants for washing can alleviate the waxing phenomenon in the water system, but the resulting extractant costs are not a small amount; although adding dispersants can alleviate the problem of catalyst clogging, the dispersed waxy substances will still precipitate in heat exchangers, tower plates and pipelines at low temperatures. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a water washing system for a methanol to olefins device, which solves the problems of fine catalyst particles, oily wax and other dirt substances entrained in the product gas adhering to and depositing on the trays of the water washing tower and the pipelines of the cooling and heat exchange equipment (cold exchange equipment), resulting in increased pressure drop in the water washing tower and decreased heat exchange efficiency of the water washing and cooling equipment.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] The invention discloses a water washing system of a methanol to olefins device, comprising a water washing tower, wherein a filtering and adsorption device is arranged at the bottom of the water washing tower, wherein a plurality of filtering and adsorption devices are arranged in parallel, wherein each of the filtering and adsorption devices comprises a filter cartridge, wherein both ends of the filter cartridge are respectively connected to a water inlet pipe and a water outlet pipe, wherein the plurality of water inlet pipes and water outlet pipes are respectively connected to a water inlet main pipe and a water outlet main pipe, wherein the water inlet main pipe is connected to the water washing tower, and the water outlet main pipe is connected to a sewage stripping tower.

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

[0011] Preferably, one or more of porous diatomaceous earth, scale inhibitor, glauber powder, wollastonite and bentonite are arranged in the filter cartridge.

[0012] Preferably, the filter adsorption device is provided with a back flushing device, the back flushing device comprises reagent inlet pipes respectively connected to the filter cartridges, the reagent inlet pipes are connected to the reagent main pipe, and the reagent main pipe is provided with a second valve, a pump and a reagent box; the other end of each filter cartridge is respectively connected to a flushing outlet pipe, the flushing outlet pipe is connected to the flushing main pipe, the flushing main pipe is connected to the reagent main pipe through a pipeline, a circulation pump is provided on the pipeline, and third valves are respectively provided on the pipelines located at both ends of the circulation pump.

[0013] Preferably, the reagent inlet pipe is arranged at one end of the filter cartridge connected to the water outlet pipe, and the flushing outlet pipe is arranged at one end of the filter cartridge connected to the water inlet pipe.

[0014] Preferably, the filter cartridge includes a first filter tank and a second filter tank that are snap-fitted and fixed, the water inlet pipe and the water outlet pipe are connected to the two ends of the first filter tank, and a filter net with an open end and an arc shape is provided in the second filter tank. The edge of the filter net extends into the second filter tank to form a column with the second filter tank, and the open end of the filter net is arranged toward the direction of the water 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 with 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 matching the sealing ring is provided at the end face of the opening of the second filter tank, and the first filter tank and the second filter tank are fixed by a clamp.

[0017] Preferably, arc grooves are respectively arranged on the side walls of the first filter groove and the second filter groove, and the clamp is placed in the arc groove to lock and fix the first filter groove and the second filter groove; a plurality of arc grooves are respectively arranged along the axial direction of the first filter groove and the second filter groove.

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

[0019] The present invention has the following beneficial effects:

[0020] The present invention can efficiently filter and absorb fine catalyst particles, oil wax and other dirt substances by arranging an adsorption and filtration device at the bottom outlet of the water washing tower; at the same time, the multiple adsorption and filtration devices can be disassembled and replaced, backwashed and activated separately, without affecting the continuous production of olefins. In addition, the present invention washes away oil wax oligomers by adding xylene or diesel for backwashing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a schematic diagram of the structure of the filtration and adsorption device of the present invention;

[0022] Figure 2 for Figure 1 Middle AA view;

[0023] Figure 3 It is a schematic diagram of the structure of the backwashing device;

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

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

[0026] In the figure: water inlet pipe 1, water outlet pipe 2, water inlet main pipe 3, water outlet main pipe 4, first valve 5, reagent inlet pipe 6, reagent main pipe 7, second valve 8, pump 9, reagent box 10, flushing outlet pipe 11, flushing main pipe 12, pipeline 13, circulation pump 14, third valve 15, first filter tank 16, second filter tank 17, filter screen 18, sealing ring 19, sealing groove 20, clamp 21, arc groove 22. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0029] refer to Figure 1-Figure 5 The present invention discloses a water washing system of a methanol to olefins device, including a water washing tower, wherein a filtering and adsorbing device is arranged at the bottom of the water washing tower, through which dirt substances such as fine catalyst particles and oil wax-like substances entrained in the product gas are quickly removed, thereby avoiding the deposition of dirt substances in the pipeline. A plurality of filtering and adsorbing devices are arranged in parallel, and each of the filtering and adsorbing devices is detachable. At the same time, filtering and adsorbing devices are added or subtracted as needed. Each of the filtering and adsorbing devices includes a filter cartridge, and the two ends of the filter cartridge are respectively connected to an inlet pipe 1 and an outlet pipe 2. The plurality of inlet pipes 1 and outlet pipes 2 are respectively connected to an inlet main pipe 3 and an outlet main pipe 4, and the inlet main pipe 3 is connected to the water washing tower, and the outlet main pipe 4 is connected to a sewage stripping tower. The water washing tower and the sewage stripping tower are both prior art.

[0030] Furthermore, each of the water inlet pipe 1 and the water outlet pipe 2 is provided with a first valve 5, and the water inlet main pipe 3 and / or the water outlet main pipe 4 is provided with a water washing tower bottom pump. The water in the water washing tower is pumped into the filtering and adsorption device by the pump, and / or the filtered water is pumped into the sewage stripping tower.

[0031] Furthermore, the filter cartridge is provided with one or more of porous diatomaceous earth, scale inhibitor, sodium sulfate, wollastonite, and bentonite, which can be prepared according to actual needs.

[0032] Furthermore, the filter adsorption device is provided with a backwashing device, which includes a reagent inlet pipe 6 connected to the filter cartridge, the reagent inlet pipe 6 is connected to the reagent main pipe 7, and the reagent main pipe 7 is provided with a second valve 8, a pump 9 and a reagent box 10; the other end of each filter cartridge is connected to a flushing outlet pipe 11, the flushing outlet pipe 11 is connected to the flushing main pipe 12, the flushing main pipe 12 is connected to the reagent main pipe 7 through a pipe 13, a circulating pump 14 is provided on the pipe 13, and a third valve 15 is provided on the pipe 13 at both ends of the circulating pump 14. It should be noted that xylene or diesel can be loaded in the reagent box for backwashing to wash away the waxy oligomers. As needed, each flushing outlet pipe and reagent inlet pipe can be provided with a valve to individually control whether each filter cartridge is passed with reagents. In addition, scale inhibitors and dispersants (polyaspartic acid, maleic acid acrylic acid copolymer, organic phosphonate reverse osmosis scale inhibitors) can also be added to react the waxy oil in the gas to flocculate and inhibit scale, thereby preventing the waxy oil oligomers from adhering and aggregating on the inner wall of the pipeline.

[0033] Furthermore, the reagent inlet pipe 6 is arranged at one end of the filter cartridge connected to the water outlet pipe 2 , and the flushing outlet pipe 11 is arranged at one end of the filter cartridge 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 and fixed, the water inlet pipe 1 and the water outlet pipe 2 are connected to the two ends of the first filter tank 16, and a filter screen 18 with an open end and an arc shape is arranged in the second filter tank 17. The edge of the filter screen 18 extends into the second filter tank 17 and is fixed, and forms an internal hollow column with the second filter tank 17 so as to load the adsorbent material. The open end of the filter screen 18 is arranged toward the water inlet pipe 1, so that the incoming water enters the second filter tank from the open end of the filter screen. At the same time, when the second filter tank is taken out to replace the adsorbent material, the adsorbent material is also prevented from spilling. Specifically, when the second filter tank is taken out, the open end of the filter screen faces upward. A handle can be arranged on the side wall of the second filter tank as needed to facilitate taking the second filter tank.

[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 with the inner wall of the first filter tank 16 to avoid a large gap between the filter screen and the first filter tank.

[0036] Furthermore, in order to achieve the sealing of the first filter tank and the second filter tank and prevent water from flowing out, 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 adapted to 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 by a clamp 21. When the first filter tank and the second filter tank are combined, the sealing ring is inserted into the sealing groove and has an interference fit, and then is locked and fixed by the clamp.

[0037] Furthermore, in order to prevent the clamp from loosening or shifting between the filter tanks when fixing the first and second filter tanks, arc grooves 22 are respectively provided on the side walls of the first filter tank 16 and the second filter tank 17, and the clamp 21 is placed in the arc groove 22 to lock and fix the first filter tank 16 and the second filter tank 17; the arc grooves 22 are respectively provided in multiple numbers along the axial direction of the first filter tank 16 and the second filter tank 17. It should be noted that the arc groove is composed of two correspondingly arranged arc strips, that is, the gap between the two arc strips is the arc groove. The clamp is located in the arc groove to play a limiting role, and the locking nut and the hinge of the clamp 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 clamp is loosened.

[0038] Furthermore, in order to fix the clamp in the arc groove, pin holes are correspondingly provided on the two arc strips, and the clamp is restricted in the arc groove by inserting the pins into the pin holes. The number of the pins can be set as required. Meanwhile, the pin holes may not be provided on the second filter tank.

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

[0040] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0041] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A water washing system for a methanol to olefins device, comprising a water washing tower, characterized in that: A filtering and adsorption device is arranged at the bottom of the water washing tower. A plurality of the filtering and adsorption devices are arranged in parallel. Each of the filtering and adsorption devices comprises a filter cartridge. Both ends of the filter cartridge are respectively connected to a water inlet pipe (1) and a water outlet pipe (2). The plurality of water inlet pipes (1) and water outlet pipes (2) are respectively connected to a water inlet main pipe (3) and a water outlet main pipe (4). The water inlet main pipe (3) is connected to the water washing tower, and the water outlet main pipe (4) is connected to a sewage stripping tower.

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

3. The water washing system of a methanol to olefins device according to claim 1, characterized in that: The filter cartridge is provided with one or more of porous diatomaceous earth, scale inhibitor, sodium sulfate, wollastonite and bentonite.

4. The water washing system of a methanol to olefins device according to claim 1, characterized in that: The filter adsorption device is provided with a backwashing device, the backwashing device comprises reagent inlet pipes (6) respectively connected to the filter cartridges, the reagent inlet pipes (6) are connected to the reagent main pipe (7), the reagent main pipe (7) is provided with a second valve (8), a pump (9) and a reagent box (10); the other end of each filter cartridge is respectively connected to a flushing outlet pipe (11), the flushing outlet pipe (11) is connected to the flushing main pipe (12), the flushing main pipe (12) is connected to the reagent main pipe (7) through a pipe (13), a circulation pump (14) is provided on the pipe (13), and third valves (15) are respectively provided on the pipe (13) at both ends of the circulation pump (14).

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

6. The water washing system of a methanol to olefins device according to claim 4, characterized in that: The filter cartridge comprises a first filter tank (16) and a second filter tank (17) which are fastened and fixed together, the water inlet pipe (1) and the water outlet pipe (2) are connected to the two ends of the first filter tank (16), a filter screen (18) with an open end and in an arc shape is arranged in the second filter tank (17), the edge of the filter screen (18) extends into the second filter tank (17) and forms a column with the second filter tank (17), and the open end of the filter screen (18) is arranged towards the water inlet pipe (1).

7. The water washing system of a methanol to olefins device according to claim 6, characterized in that: 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 fits against the inner wall of the first filter tank (16).

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

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

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

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