Method and device for reducing operating load of methanol to olefins stripper

Abstract

The present invention discloses a method and device for reducing the operating load of a methanol-to-olefins stripping tower, the method comprising: sending the product gas generated from the methanol-to-olefins process into a quenching tower for washing and cooling with quenching water to obtain quenched product gas and quenched water turbidity liquid; sending the quenched product gas into a water washing tower for further washing and cooling with washing water to obtain washed product gas and washing water turbidity liquid; circulating part of the quenching water turbidity liquid and part of the washing water turbidity liquid to the quenching tower and the water washing tower; sending part of the quenching water and part of the washing water into a microchannel separator for treatment to remove particulate matter and part of organic matter therein to obtain quenching water clear liquid and washing water clear liquid; sending the quenching water clear liquid and the washing water clear liquid into a stripping tower for treatment to obtain purified water. The present invention can effectively remove fine catalysts and easily condensed oil wax substances in the influent of the stripping tower, so as to reduce the operating load of the stripping tower and extend the operation cycle of the stripping tower.

Description

Technical Field

[0001] The invention belongs to the technical field of high-concentration refractory wastewater treatment, and relates to a method and a device for reducing the operating load of a methanol-to-olefins stripping tower, which is suitable for removing and concentrating particulate matter in methanol-to-olefins purified water. Background Art

[0002] The methanol to olefins (MTO) process is a chemical technology that uses coal-based or natural gas-based methanol as a raw material to produce low-carbon olefins. Some catalyst particles will be entrained in the reaction product gas, and a multi-stage cyclone separator is usually used to recover the catalyst. However, due to the limitation of the separation accuracy of the cyclone separator, it is difficult to separate the micron and submicron fine particles that are worn out, which eventually leads to the fine particles entering the subsequent water system. The MTO water system mainly includes a quenching water circulation system, a water washing water circulation system, and a stripping system. The product gas recovered by the catalyst is sent to the quenching tower and the water washing tower in turn for cooling and washing, and most of the catalyst fine powder and organic pollutants entrained in the product gas are washed away. Since 54%wt of the reaction product in the MTO process is water, in order to maintain the balance of water in the quenching and water washing systems, the quenching tower and the water washing tower need to discharge a part of the quenching water and water washing water to the stripping tower, and the oxygen-containing compounds in the stripping water are returned to the reactor for refining. The purified water at the bottom of the stripping tower is sent to the sewage treatment plant for treatment and utilization after heat exchange and cooling. Since the quench water and the washing water contain catalyst fine powder and easily condensed oil and wax substances, they will emulsify to form sludge and emulsion during the condensation and accumulation process in the subsequent water system, which will accelerate the clogging of the tower plates, heat exchangers, air coolers and other equipment in the water system. At the same time, it also makes the separation of recycled water more difficult, greatly increasing the energy consumption of the device. In particular, the content of catalyst fine powder in the quench water is as high as 300-500 mg / L, and the content of oil and wax substances in the washing water is as high as 400-500 mg / L. If the oil and wax substances cannot be effectively removed, the quench water, washing water, etc. will be mixed into the stripping tower, and the oil and wax substances will condense and stick to the catalyst particles carried by the stripping tower, which will increase the operating load of the stripping tower, affect the efficiency of the stripping tower, and make the stripping tower unable to effectively strip out the oxygen-containing compounds in the stripping tower inlet water. This not only causes energy waste but also increases the burden on the sewage treatment plant. In order to reduce the operating load of the stripping tower and ensure its efficient operation, it is necessary to effectively and synergistically remove the easily condensed oil wax substances and particulate matter in the stripping tower inlet water.

[0003] Chinese invention patent application publication specification CN101352621A discloses a method and device for desolidification of MTO quench water and washing water by cyclone flow, Chinese invention patent application publication specification CN101352620A discloses a method and device for concentrating fine catalyst in MTO quench water and washing water by micro-cyclone flow, and Chinese invention patent application specification CN 102093153B discloses a method and device for optimizing the combination purification and separation of MTO catalyst-containing micro-powder reaction gas, all of which use a cyclone separator to remove the catalyst entrained in quench water and washing water. Limited by the separation accuracy of the cyclone separator, this method has poor separation effect on particles below 2.5μm in actual application, resulting in the inability to effectively remove fine particles.

[0004] Chinese invention patent application publication specification CN205031975U discloses a MTO quench water and wash water purification treatment device, Chinese invention patent application publication specification CN104649446A discloses a MTO quench water and wash water liquid-solid separation method and device, and Chinese invention patent application publication specification CN10192246A discloses a MTO process wastewater treatment and reuse method. The above methods all use precision filtration to separate and concentrate the catalyst in the quench water and wash water. However, since the catalyst particles entrained in the quench water and wash water are small in size and the water contains a small amount of oil and wax substances, the filter is easily blocked during actual operation. The device has a short operating cycle and a small processing capacity. Acid and alkali agents need to be added during the backwash regeneration process, and online backwash regeneration is difficult, resulting in excessive operating pressure difference of the equipment and inability to use normally.

[0005] Chinese invention patent application publication specification CN102050548A discloses a method for treating MTO wastewater, and Chinese invention patent application publication specification CN105330086A discloses a method for treating methanol to olefins wastewater. Both of the above methods remove colloids and suspended solids in water by homogenization adjustment and coagulation sedimentation. When this method is actually applied, the homogenization tank and sedimentation tank occupy a large area, the treatment cycle is long, and continuous input of coagulants and flocculants is required, resulting in high operating costs. The solid content of the wastewater treated by this method is still about 100 mg / L, the removal efficiency of suspended solids is low, and fine particles that are not easy to settle cannot be effectively removed. Summary of the invention

[0006] In view of this, the main purpose of the present invention is to provide a method and device for reducing the operating load of a methanol to olefins stripping tower. The present invention can effectively remove fine catalysts and easily condensed oil wax substances in the stripping tower inlet water to reduce the operating load of the stripping tower and extend the stripping tower operation cycle.

[0007] To achieve the above-mentioned object of the invention, the first aspect of the present invention provides a device for reducing the operating load of a methanol to olefins stripping tower, the device comprising a quenching tower, a water washing tower, a microchannel separator and a stripping tower;

[0008] The quenching tower is used to use quenching water to wash and cool the product gas generated from the methanol to olefins process to obtain quenched product gas and quenching water turbidity; and the quenching tower is provided with a quenching water turbidity circulation pipeline for circulating part of the quenching water turbidity into the quenching tower for use as the quenching water;

[0009] The water washing tower is connected to the quenching tower, and the water washing tower is used to use washing water to wash and cool the quenched product gas again to obtain washed product gas and washing water turbidity liquid; and the water washing tower is provided with a washing water turbidity liquid circulation pipeline, which is used to circulate part of the washing water turbidity liquid into the water washing tower for use as the washing water;

[0010] The microchannel separator is connected to the quenching tower, and is used to receive part of the quenching water turbidity and remove particulate matter and part of organic matter therein to obtain quenching water clear liquid; and the microchannel separator is connected to the water washing tower, and is used to receive part of the washing water turbidity and remove particulate matter and part of organic matter therein to obtain washing water clear liquid;

[0011] The stripping tower is in communication with the microchannel separator and is used for receiving and treating the quenching water supernatant and the washing water supernatant to obtain purified water.

[0012] In a preferred embodiment, the device also includes a sedimentation tank, which is connected to the quenching tower and is used to send the portion of the quenching water turbidity into the microchannel separator after sedimentation separation; and the sedimentation tank is connected to the water washing tower and is used to send the portion of the washing water turbidity into the microchannel separator after sedimentation separation.

[0013] In a preferred embodiment, the device further comprises a first heat exchanger, a first air cooler, a second heat exchanger and a second air cooler, and the quenching water turbid liquid used as the quenching water is cooled by the first heat exchanger and the first air cooler in sequence and then sent to the quenching tower for use; and,

[0014] The washing water turbid liquid used as the washing water is cooled down by the second heat exchanger and the second air cooler in sequence, and then sent to the washing tower for use.

[0015] In a preferred embodiment, the microchannel separator comprises a tower body, wherein the tower body is provided with a feed channel for introducing the quenched water turbid liquid and the water-cooled water turbid liquid, a filter material filling area for filling filter material, and a clear liquid containing chamber for containing the quenched water clear liquid and the water-cooled water clear liquid;

[0016] The feed channel comprises a liquid outlet section inserted into the filter material filling area, and the liquid outlet section is provided with a plurality of liquid outlet holes communicated with the filter material filling area at intervals along its axial direction;

[0017] The filter material filling area is located between the liquid outlet section of the feed channel and the clear liquid containing chamber, and the clear liquid containing chamber is provided with a liquid inlet hole communicating with the filter material filling area;

[0018] The clear liquid containing cavity is provided with a water outlet hole for outputting the water phase in the quenched clear water liquid and the water-cooled clear water liquid, and an oil outlet hole for outputting the oil phase in the quenched clear water liquid and the water-cooled clear water liquid.

[0019] In a preferred embodiment, the microchannel separator further comprises a cyclone, the cyclone comprising a cylindrical body and a conical body connected to the bottom of the cylindrical body, the side wall of the cylindrical body is provided with a material inlet, the top of the cylindrical body is provided with a material outlet, and the bottom of the conical body is provided with a regenerated filter material outlet;

[0020] The tower body is provided with an overflow port communicating with the filter material filling area and a regenerated filter material inlet, the overflow port is communicated with the feed inlet of the cyclone, and the regenerated filter material inlet is communicated with the regenerated filter material outlet of the cyclone.

[0021] In a preferred embodiment, the tower body is provided with a backwash inlet for introducing regeneration gas and backwash liquid into the filter material filling area;

[0022] Preferably, the backwash inlet is arranged below the filter material filling area.

[0023] Preferably, a distributor acting on the regeneration gas and the backwash liquid is provided at the bottom of the filter material filling area, and the backwash inlet is connected to the distributor.

[0024] In a preferred embodiment, a plurality of the microchannel separators are provided, and the plurality of microchannel separators are connected in parallel.

[0025] The second aspect of the present invention provides a method for reducing the operating load of a methanol to olefins stripper using the above device, the method comprising:

[0026] The product gas generated from the methanol to olefins process is sent to a quench tower to be washed and cooled with quench water to obtain quenched product gas and quench water turbid liquid;

[0027] The quenched product gas is sent to a water washing tower to be washed again and cooled with washing water to obtain washed product gas and washing water turbidity;

[0028] Circulating part of the turbid quenching water to the quenching tower for use as the quenching water, and circulating part of the turbid washing water to the washing tower for use as the washing water;

[0029] Sending part of the turbid quench water into a microchannel separator for treatment to remove particulate matter and part of organic matter therein to obtain a clear quench water solution;

[0030] sending part of the turbid washing liquid into a microchannel separator for treatment to remove particulate matter and part of organic matter therein to obtain a clear washing liquid;

[0031] The quench water supernatant and the washing water supernatant are sent to a stripping tower for treatment to obtain purified water.

[0032] In a preferred embodiment, the method further comprises: the part of the quenching water turbidity liquid and the part of the washing water turbidity liquid are sent to a microchannel separator after sedimentation separation;

[0033] The turbid washing water used as the washing water is cooled and then sent to the washing tower for use;

[0034] The turbid quenching water used as the quenching water is sent to the quenching tower for use after the temperature is reduced.

[0035] In a preferred embodiment, the method further comprises:

[0036] When the filter material in the microchannel separator needs to be regenerated, the quenching water turbid liquid and the water-cooling water turbid liquid are stopped from being fed into the microchannel separator for filter material regeneration, and the regeneration gas and the backwashing liquid are introduced into the filter material filling area of ​​the microchannel separator through the backwashing inlet to backwash the filter material in the filter material filling area and make the filter material filling area form a boiling state;

[0037] The backwash liquid carries the filter material into the cyclone from the overflow port, and removes the particulate matter and organic matter from the quenched water turbid liquid and the water-cooled water turbid liquid attached to the filter material to obtain regenerated filter material. The regenerated filter material flows back from the regenerated filter material outlet to the filter material filling area, and the removed particulate matter and organic matter are discharged from the discharge port.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The method of the present invention sends the product gas containing catalyst particles and various by-products from the methanol to olefin process into a quenching tower, washes and cools it with quenching water, washes away part of the entrained catalyst, and obtains quenched product gas and quenched water turbid liquid; sends the quenched product gas into a water washing tower for washing and cooling again with washing water, washes away the entrained catalyst particles and oily wax substances, and obtains washed product gas and washed water turbid liquid; the washed product gas is sent to a subsequent treatment system. Part of the quenched water turbid liquid returns to the quenching tower for circulation therein, and part of the washed water turbid liquid returns to the water washing tower for circulation therein. In order to maintain the balance of the water system, a part of the quenched water turbid liquid and the washed water turbid liquid is discharged and sent to a microchannel separator for deep purification, and the oily wax substances and catalyst particles entrained in the water are removed before entering the stripping tower. Through the above method, the catalyst particles and oily wax-like organic matter content in the quenched water turbid liquid and the washed water turbid liquid entering the stripping tower can be reduced, the blockage of the stripping tower can be reduced, and the processing difficulty and operation load of the stripping tower can be reduced.

[0040] The method of the present invention utilizes the particle bed in the microchannel separator to purify the water in the stripping tower, and the filter material simultaneously intercepts, adsorbs, and demulsifies oil wax substances and particles in the water, so that the content of oil wax and particles in the water gradually decreases with the depth of the filter layer. Compared with fine filtration, this method has simple equipment, low investment, easy regeneration of filter material, low energy consumption, and low maintenance cost.

[0041] In particular, the method of the present invention can also control the flow rate of the quenching water turbidity liquid and the washing water turbidity liquid entering the microchannel separator, so as to adjust the proportion of the quenching water turbidity liquid and the washing water turbidity liquid in the total feed amount of the stripping tower as needed, so that the stripping tower feeding process has great operational flexibility.

[0042] In particular, after the microchannel separator has been running continuously for a period of time, the filter material in the microchannel separator can be regenerated by regeneration gas and backwash liquid to release the adsorbed catalyst particles and oil wax substances, so that it can be used repeatedly and stably.

[0043] Other features and advantages of the present application will be described in detail through the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic diagram of a process flow of a method for reducing an operating load of a methanol to olefins stripping tower in one embodiment;

[0045] Figure 2 A schematic diagram of the structure of a microchannel separator in one embodiment;

[0046] Figure 3 A schematic diagram of a plurality of microchannel separators arranged in parallel in one embodiment. DETAILED DESCRIPTION

[0047] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0048] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0049] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] After extensive and in-depth research, the inventors of the present invention found that the water in the stripper in the methanol to olefins device has the characteristics of large operating flow, low solid content, small particle size, alcohol, aldehyde, ketone, ether and various oil wax substances as reaction by-products, and the entrained catalyst particles have lipophilic wax substances. For this type of wastewater, the most effective and lowest cost method is to use a cyclone separator group for separation, but it is found in actual application that this method is not efficient in removing oil wax substances. The precision filtration device has limited processing capacity, short continuous operation time, easy clogging, and difficulty in cleaning the filter membrane, and requires the addition of agents, which increases the operating cost. In order to solve the above problems, that is, to achieve higher filtration efficiency and better oil separation effect, the inventors use a microchannel separator to synergistically separate oil wax substances and catalyst particles in the stripper inlet water. This method not only solves the problem of low removal efficiency of oil wax substances by the original cyclone separator group, but also avoids the defects of small processing capacity and frequent backwashing in the ultrafiltration membrane filtration method, and this method has lower equipment cost, lower energy consumption and more reliable operation than the ultrafiltration membrane filtration method.

[0051] refer to Figure 1The main idea of ​​the present invention is to provide a device for reducing the operating load of a methanol to olefins stripping tower, the device comprising: a quenching tower 1, a water washing tower 2, a microchannel separator 3 and a stripping tower 4;

[0052] The quench tower 1 is used to wash and cool the product gas generated from the methanol to olefins process using quench water to obtain quenched product gas and quench water turbid liquid;

[0053] The water washing tower 2 is connected to the quenching tower 1, and the water washing tower 2 is used to use washing water to wash and cool the quenched product gas again to obtain washed product gas and washing water turbidity;

[0054] The microchannel separator 3 is connected to the quench tower 1 and the water washing tower 2 respectively, and is used to receive part of the quench water turbidity from the quench tower 1 and remove particulate matter and part of organic matter therein to obtain a quench water clear liquid; and is used to receive part of the washing water turbidity from the water washing tower 2 and remove particulate matter and part of organic matter therein to obtain a washing water clear liquid;

[0055] The stripping tower 4 is in communication with the microchannel separator 3 and is used for receiving and treating a portion of the quench water supernatant and the washing water supernatant to obtain purified water.

[0056] Preferably, the device also includes a sedimentation tank 5, which is connected to the quenching tower 1 and is used to send the portion of the quenching water turbidity into the microchannel separator 3 after sedimentation separation; and the sedimentation tank 5 is connected to the water washing tower 2 and is used to send the portion of the washing water turbidity into the microchannel separator 3 after sedimentation separation.

[0057] It is understandable that valves can be set as needed on the material conveying pipeline between the quenching tower 1 and the settling tank 5 or on the material conveying pipeline between the water washing tower 2 and the settling tank 5 to control the amount of quenching water turbidity and water washing water turbidity entering the settling tank 5. It is understandable that the number of settling tanks 5 can be one or more in series. Similarly, valves can be set as needed on the material conveying pipeline between the settling tank 5 and the microchannel separator 3 to control the amount of quenching water turbidity and water washing water turbidity entering the microchannel separator 3; and valves can be set as needed on the material conveying pipeline between the microchannel separator 3 and the stripping tower 4 to control the amount of quenching water clear liquid and water washing water clear liquid entering the stripping tower 4.

[0058] Preferably, the device further comprises a first heat exchanger 6, a first air cooler 7, a second heat exchanger 8 and a second air cooler 9, and the quenching water turbid liquid used as the quenching water is cooled by the first heat exchanger 6 and the first air cooler 7 in sequence and then sent to the quenching tower 1 for use; and,

[0059] The washing water turbid liquid used as the washing water is cooled down by the second heat exchanger 8 and the second air cooler 9 in sequence, and then sent to the washing tower 2 for use.

[0060] In a specific example, Figure 1 As shown, the quenching water turbid liquid is pumped to the top of the quenching tower through the first delivery pipeline I and circulates in the tower, and the washing water turbid liquid is pumped to the top of the washing tower through the second delivery pipeline II and circulates in the tower. The first delivery pipeline I is provided with a first air cooler 6 and a first heat exchanger 7 for heat exchange and cooling of the quenching water turbid liquid, and the second delivery pipeline II is provided with a second air cooler 8 and a second heat exchanger 9 for heat exchange and cooling of the washing water turbid liquid. It can be understood that a circulation pump can be provided as needed on the first delivery pipeline I or the second delivery pipeline II according to the material flow direction to realize the circulation of the material, and a valve can be provided as needed to control the flow rate of the material.

[0061] In the present invention, a part of the quenching water turbidity of the quenching tower 1 is directly circulated into the quenching tower for reuse after heat exchange, and a part of the quenching water turbidity is discharged to the settling tank 5. A part of the water-cooled water turbidity of the water washing tower 2 is directly circulated into the water washing tower for reuse after heat exchange, and a part of the water-cooled water turbidity is discharged to the settling tank 5. The microchannel separator 3 purifies the quenching water turbidity and the water-cooled water turbidity in the settling tank 5.

[0062] refer to Figure 2Preferably, the microchannel separator 3 used includes a tower body 30, which is provided with a feed channel 31 for introducing quenching water turbid liquid and washing water turbid liquid, a clear liquid containing chamber 34 for containing quenching water clear liquid and washing water clear liquid, and a filter material filling area 35 for filling filter material. Among them, the feed channel 31 includes a liquid outlet section 32 inserted into the filter material filling area 35, the liquid outlet section 32 is entirely in a state of being inserted into the filter material filling area 35, and the liquid outlet section 32 is provided with a plurality of liquid outlet holes (not shown in the figure) connected to the filter material filling area 35 at intervals along its axial direction; the filter material filling area 35 is located between the liquid outlet section 32 of the feed channel 31 and the clear liquid accommodating chamber 34, and the clear liquid accommodating chamber 34 is provided with a liquid inlet hole (not shown in the figure) connected to the filter material filling area 35; the clear liquid accommodating chamber is provided with a water outlet hole 36 for outputting the water phase in the quenched water clear liquid and the water-cooled water clear liquid, and an oil outlet hole 37 for outputting the oil phase in the quenched water clear liquid and the water-cooled water clear liquid. Specifically, the quenched water turbid liquid and the washing water turbid liquid from the settling tank 5 enter the feed channel 31 through the feed port 33, and enter the filter material filling area 35 through a plurality of liquid outlet holes spaced along the axial direction on the liquid outlet section 32 of the feed channel 31. In the filter material filling area 35, the quenched water turbid liquid and the washing water turbid liquid are generally filtered in a transverse flow, and the particulate matter and oily wax-like organic matter in the quenched water turbid liquid and the washing water turbid liquid are filtered out by the filter material. The obtained quenched water clear liquid and the washing water clear liquid enter the clear liquid containing chamber 34 through the water inlet hole of the clear liquid containing chamber 34, and flow out from the water outlet hole 36 and enter the stripping tower through the conveying pipeline. Due to the density difference between water and oil, the oil phase separated by the filter material flows out from the oil outlet hole 37. Preferably, the liquid level of the fluid during the filtration process can also be controlled by setting a liquid level meter 38.

[0063] In some specific embodiments, see Figure 2The liquid outlet section 32 of the feed channel 31 is arranged along the axial direction of the tower body 30, and the liquid outlet section 32 is inserted as a whole into the filter material filling area 35, that is, the filter material filling area 35 surrounds the periphery of the liquid outlet section 32, and the clear liquid accommodating chamber 34 is located at the periphery of the filter material filling area 35, and the liquid outlet holes of the liquid outlet section 32 are uniformly opened at intervals in the upper and lower directions of the entire liquid outlet section 32 along the axial direction thereof. After the quenched water turbidity and the washing water turbidity enter the feed channel 31, they flow out from the liquid outlet holes of the liquid outlet section 32, so that there are multiple intervals of quenched water and washing water streams entering the entire depth of the filter material filling area 35, which can effectively realize the separation of particulate matter and oily wax-like organic matter in the filter material, and the obtained quenched water clear liquid and washing water clear liquid have lower particulate matter content and oily wax-like organic matter content, which is conducive to better reducing the occurrence of blockage after passing them into the stripping tower 4. In the microchannel separator 3 of the specific structure of the present invention, the flow direction of the quenching water turbidity and the washing water turbidity entering the filter material filling area 35 is generally horizontal flow, which is different from the vertical flow of the traditional separator, and is conducive to forming a slower flow rate; and in the microchannel separator 3 of the specific structure of the present invention, the oil organic matter in the quenching water turbidity and the washing water turbidity that are generally diffused in horizontal flow is adsorbed, agglomerated and grown by the filter material, and due to the density difference, it will continue to migrate upward, so that the filter material surface is updated, which is conducive to the continuous adsorption and separation of the oil organic matter. In the traditional separator, it is basically vertical flow, and the wastewater fluid will provide a drag force to the oil organic matter adsorbed on the filter material, causing the oil organic matter to be always in the filter material, which is not conducive to the renewal of the filter material surface, and the oil organic matter will even migrate downward, and even penetrate the bed layer, resulting in poor wastewater treatment effect.

[0064] Further, see Figure 2The microchannel separator 3 further includes a cyclone 39, and the number of the cyclones 39 can be one or more. The cyclone 39 includes a cylindrical barrel 49 and a conical barrel 50 connected to the bottom of the cylindrical barrel 49, the side wall of the cylindrical barrel 49 is provided with an inlet 52, the top of the cylindrical barrel 49 is provided with an outlet 53, and the bottom of the conical barrel 50 is provided with a regenerated filter material outlet 51. The tower body 30 is provided with an overflow port 55 and a regenerated filter material inlet 56 connected to the filter material filling area 35, the overflow port 55 is connected to the inlet 52 of the cyclone 39 through a pipeline, and the regenerated filter material inlet 56 is connected to the regenerated filter material outlet 51 of the cyclone 39 through a pipeline. The tower body 30 is provided with a backwash inlet 40 for introducing regeneration gas (such as nitrogen or air) and backwash liquid into the filter material filling area 35, preferably, the backwash inlet 40 is arranged below the filter material filling area 35. Preferably, a distributor 41 for distributing regeneration gas and backwash liquid is provided at the bottom of the filter material filling area 35, and the backwash inlet 40 is connected to the distributor 41; the distributor 41 is provided with multiple outlets so that the regeneration gas and backwash liquid can evenly enter the filter material filling area 35, so as to achieve a better backwash effect. Specifically, a free space is reserved in the inner cavity of the tower body 30 corresponding to the area above the filter material filling area 35, and the overflow port 55 and the regenerated filter material inlet 56 are both arranged on the side wall of the tower body 30 corresponding to the free space, wherein the overflow port 55 is located above the regenerated filter material inlet 56; preferably, a one-way valve is provided on the connecting pipeline between the regenerated filter material outlet 51 and the regenerated filter material inlet 56, so that the connecting pipeline can only allow the material to flow from the regenerated filter material outlet 51 to the regenerated filter material inlet 56. Preferably, an exhaust port 42 is also provided on the tower body 30 of the present invention, and the exhaust gas in the tower body 30 can be discharged through the exhaust port 42 as needed.

[0065] In the microchannel separator of the present invention, a cyclone of a specific structure is adopted, and the cyclone is arranged outside the microchannel separator. Through the cooperation of the cyclone of the specific structure and the tower body of the microchannel separator, the cyclone can generate a cyclonic field for the material entering therein, and can provide a larger centrifugal force, thereby obtaining a better filter material regeneration effect. The method of the present invention also includes: when the filter material in the microchannel separator 3 needs to be regenerated, stop feeding the quenched water turbid liquid and the water-cooled water turbid liquid into the microchannel separator 3 that needs to regenerate the filter material, and introduce regeneration gas and backwashing liquid into the filter material filling area 35 of the microchannel separator 3 through the backwashing inlet 40 to backwash the filter material in the filter material filling area 35. During the backwashing process, the material in the filter material filling area 35 can be made to form a boiling state, that is, a boiling bed. Specifically, the filter material filling area can be made to form a boiling state by adjusting the flow rate of the regeneration gas and the backwashing liquid. With the continuous introduction of the regeneration gas and the backwashing liquid, the backwashing liquid carries the filter material into the cyclone 39 from the overflow port 55, specifically into the cylindrical barrel 49 of the cyclone 39, and forms a cyclone in the cylindrical barrel 49. During the cyclone process, due to the strong flow shearing effect, the filter particles in the cyclone 39 will rotate at high speed while revolving. The rotation and revolution generate periodic strong coupling centrifugal force, which promotes the outward migration of pollutants on the surface of the filter particles and in the pores. That is, the self-revolution of the filter particles can drive the micro-interface oscillation of the filter particles to achieve the desorption of oily waxy organic pollutants and the separation of fine catalyst particles, thereby achieving efficient regeneration of the filter material, thereby obtaining regenerated filter material. The regenerated filter material enters the conical cylinder 50 during the cyclone process, and flows back from the regenerated filter material outlet 51 to the filter material filling area 35 of the tower body 30, while the removed catalyst fine powder and oily waxy organic matter overflow and are discharged from the discharge port 53, for example, discharged to the downstream concentration system (for example, entering the downstream sedimentation tank) for further treatment. In some embodiments, the filter material used is loaded according to a certain particle size gradient or density gradient. In this case, the regenerated filter material that flows back into the tower body 30 will naturally settle and stratify according to its particle size and density gradient during the flow process after entering the tower body 30, forming a filter material loading form similar to the original sorting method; in some embodiments, the filter material can also be a filter material with a single particle size gradient or density gradient.

[0066] In a preferred embodiment, a plurality of microchannel separators 3 connected in parallel are used in the method of the present invention. When one or some microchannel separators 3 need to regenerate the filter material (for example, the filter material is regenerated after the microchannel separator 3 runs for a preset time or the pressure difference reaches a preset value), other microchannel separators 3 that do not need to regenerate the filter material can be used to continue to process the quench water and the water-cooled water to maintain the continuity of operation.

[0067] Figure 3The schematic diagram of the pipeline connection of multiple microchannel separators 3a, 3b, etc. connected in parallel in one embodiment is illustrated. The inlet 33 of the feed channel 31 of each microchannel separator is connected to the outlet of the quenching water turbidity and the washing water turbidity of the settling tank 5 through a pipeline, so that the quenching water turbidity and the washing water turbidity can be sent into the feed channel 31. During normal operation, the water inlet of the stripping tower is fed from the top inlet of the equipment and discharged from the side outlet. After removing the catalyst particles entrained in the water, it is sent to the stripping tower 4, and the oil phase outlet is used for waste oil recovery. When the equipment runs continuously for a certain period of time or the pressure difference rises to a certain value, the equipment switches to the backwashing operation in turn. During backwashing, close the equipment inlet valve 61 and outlet valve 66, open the filter material regenerator inlet valve 69, drain valve 63, exhaust valve 62, and open the nitrogen inlet valve 64 and backwash valve 65 at the same time. The particle bed in the microchannel separator is made to boil by the water and nitrogen inlet of the stripping tower, and the oil wax organic matter and catalyst particles intercepted and adsorbed in the particle bed are released to achieve the regeneration of the filter material. The regenerated concentrated catalyst slurry is discharged through the drain valve 63 and sent to the sedimentation concentration system for further treatment. When the filter material is regenerated, reopen the inlet valve 61 and outlet valve 66, close the filter material regenerator inlet valve 69, drain valve 63, exhaust valve 62, nitrogen inlet valve 64 and backwash valve 65.

[0068] In the present invention, the above-mentioned regeneration gas can be, for example, nitrogen, air, etc., and the recoil liquid can be, for example but not limited to, the quenching water turbidity liquid output from the quenching tower 1 and the washing water turbidity liquid output from the washing tower 2, or the quenching water clear liquid, washing water clear liquid or other suitable fluids produced in the microchannel separator 3.

[0069] In the microchannel separator 3 of the present invention, the filter material used is not particularly limited, and can be various filter materials conventionally used in the art, such as but not limited to quartz sand, anthracite, fruit shells, activated carbon, alumina particles, carbon balls or ceramic balls, etc. In some specific embodiments, illustratively, the catalyst used in the methanol to olefins process is, for example, micron-sized and / or nano-sized, and the filter material used is, for example, millimeter-sized.

[0070] It is understandable that the above-mentioned device for reducing the operating load of the methanol to olefins stripping tower of the present invention can be extended to various heterogeneous separation occasions where liquids entrain oil wax substances or fine suspended particles or both.

[0071] Another aspect of the present invention provides a method for reducing the operating load of a methanol to olefins stripping tower, the method comprising:

[0072] The product gas generated from the methanol to olefins process is sent to a quench tower, and the product gas is washed and cooled with quench water in the quench tower. In the process of washing and cooling the product gas with the quench water, the micro-nano catalyst fine powder entrained in the product gas is washed into the quench water to obtain the quenched product gas and the quench water turbid liquid;

[0073] The quenched product gas is sent to a water washing tower, where it is washed and cooled again with washing water to wash away the remaining catalyst fine powder and condensed organic matter (forming waxy organic matter) in the product gas, thereby obtaining washed product gas and washed water turbidity;

[0074] Circulating part of the turbid quenching water to the quenching tower for use as the quenching water, and circulating part of the turbid washing water to the washing tower for use as the washing water;

[0075] Sending part of the quenched water turbidity into a microchannel separator for treatment to remove particulate matter and part of organic matter (mainly oily waxy organic matter) therein to obtain quenched water clear liquid;

[0076] Sending part of the turbid water washing liquid into a microchannel separator for treatment to remove particulate matter and part of organic matter (mainly oily waxy organic matter) therein to obtain a clear water washing liquid;

[0077] The quenched water clear liquid and the washed water clear liquid are sent to a stripping tower for treatment to strip the organic matter therein to obtain purified water.

[0078] Preferably, the methanol feedstock is reacted in a fluidized bed reactor, and the obtained product gas is sent to a quench tower and a water washing tower in sequence after the catalyst particles are recovered through a multi-stage cyclone separator.

[0079] Preferably, the quenching water turbid liquid used as the quenching water is cooled by the first heat exchanger and the first air cooler before being sent to the quenching tower for use. The specific cooling temperature can be determined according to the process requirements, for example, the temperature of the quenching water turbid liquid is controlled to about 60°C before entering the quenching tower; the washing water turbid liquid used as the washing water is cooled by the second heat exchanger and the second air cooler before being sent to the washing tower for use. The specific cooling temperature can be determined according to the process requirements, for example, the temperature of the washing water turbid liquid is controlled to about 60°C before entering the washing tower.

[0080] In the present invention, preferably, by controlling the flow rate of the quenching water turbid liquid and the washing water turbid liquid entering the microchannel separator, the proportion of the quenching water turbid liquid and the washing water turbid liquid in the total feed amount of the stripping tower can be adjusted as needed, so that the stripping tower feeding process can be operated flexibly. The washing tower turbid liquid mainly contains oil, and the quenching tower turbid liquid mainly contains solids. According to the actual separation effect of the microchannel separator, the flow rate ratio of the washing water turbid liquid and the quenching water turbid liquid can be adjusted as appropriate to reduce the extreme working conditions and working condition fluctuations of the stripping tower.

[0081] Preferably, part of the quenched water turbid liquid and part of the washed water turbid liquid are first settled and separated before being sent to the microchannel separator. Sedimentation can initially separate the solids and oil in the settling tank, reduce the concentration of pollutants entering the microchannel separator, extend the operating time of the microchannel separator, and ensure the separation effect of the microchannel separator.

[0082] In some embodiments, the stripping tower inlet water operating temperature is 90-150° C., and the solid particles are methanol to olefins catalyst fine powder, usually crushed SAPO-34 molecular sieve, with a content of 20-220 mg / L and an average particle size of 0.5-45 μm.

[0083] In some embodiments, the total oil content of the quenched water turbidity obtained from the quenching tower is 5-1000 mg / L; the total oil content of the washing water turbidity obtained from the water washing tower is 20-5000 mg / L. After microchannel separation, the content of easily condensable oil wax substances in the water is reduced to below 25 mg / L, the catalyst content in the water is reduced to below 5 mg / L, and the average particle size is reduced to below 0.3 μm. In the present invention, the stripping tower influent from the settling tank contains not only a relatively high amount of oil wax substances, but also a certain amount of solid fine catalyst particles. The microchannel separator is used to synergistically remove the oil wax substances and fine catalyst particles, purify the stripping tower influent water quality, and reduce the fluctuation of the stripping tower influent water quality.

[0084] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the following is a reference to the attached Figure 1-3 The system and method flow of the present invention are further described in detail with reference to embodiments.

[0085] Example 1

[0086] In a 1.2 million tons / year methanol to olefins process, its product gas is treated according to the method of the present invention. The treatment process flow is shown in FIG. Figure 1 , wherein the structural diagram of the microchannel separator is shown in Figure 2 The quenched water turbidity liquid and the water-cooled water turbidity liquid containing the solid catalyst and organic matter are treated by a microchannel separator. The specific description of the treatment method and the microchannel separator used can be referred to the previous description, and will not be repeated here. Figure 2 The microchannel separator shown in the figure is used to illustrate the treatment effect of quenched water turbidity liquid and water-cooled water turbidity liquid in a small test:

[0087] 1.Material properties and related parameters

[0088] The influent water (quench water clear liquid and water washing water clear liquid) of the methanol to olefins stripper is a liquid-solid two-phase mixture, containing solid catalyst fine powder and oil wax substances, of which water is the continuous phase, and the solid catalyst and oil wax substances are the dispersed phase medium. The experimental device has a processing capacity of 50L / h, and the density under liquid phase operation is 915.4kg / m 3 , viscosity is 0.255 cP, the temperature of the stripping tower inlet water is 139°C, the content of spent catalyst in the stripping tower inlet water is 60 mg / L, the average particle size of the spent catalyst is 2.0 μm, and the content of oil wax substances in the stripping tower inlet water is 350 mg / L.

[0089] 2. Stripping tower water purification device

[0090] The tower body diameter of a single microchannel separator is 72mm, the filter media is porous organic polymer particles with a particle size of 0.5-1mm, the filter bed thickness in the filter media filling area is 1000mm, and the processing capacity of a single microchannel separator is 50L / h.

[0091] 3. Implementation process

[0092] like Figure 1 As shown, the product gas containing catalyst particles and various by-products is sent to the quenching tower 1 for washing and cooling, and after washing away part of the entrained catalyst, it is sent to the water washing tower 2 for cooling again, washing away the entrained catalyst particles and oil wax substances, and the product gas is sent to the subsequent treatment system. The quenching water turbidity and the water washing water turbidity are returned to the top of the tower after heat exchange and cooling through the first air cooler 6, the first heat exchanger 7, the second air cooler 8, and the second heat exchanger 9, and circulate in the quenching and water washing system. At the same time, a part of the quenching water turbidity and the water washing water turbidity are discharged and sent to the sedimentation tank 5, and then pumped into the microchannel separator 3, and the oil wax substances and catalyst particles entrained in the water are removed and sent to the stripping tower 4, and part of them are refluxed through the reflux tank 10, and part of them are sent to the reactor for refining. Part of the water at the bottom of the stripping tower is vaporized in the kettle reboiler 11 as stripping steam, and part of it is sent to the sewage treatment plant. After the microchannel separator has been running continuously for a period of time, the filter material is regenerated by reverse feeding the stripping tower water to release the adsorbed oil wax substances and catalyst particles.

[0093] like Figure 2 As shown, during normal operation, the stripping tower inlet water (quenching water clear liquid and washing water clear liquid) is fed from the top feed port 33 of the equipment, and is uniformly radially sent outward to the filter material filling area 35 through the feed distribution structure. After the filter material is separated, the purified water flows out from the water outlet 36. Due to the density difference between water and oil, the oil separated by the filter material flows out from the oil outlet 37. The liquid level of the fluid in the filtration process is controlled by the liquid level meter 38. After running for a period of time until the pressure difference rises to 0.3MPa, the equipment is switched to the backwashing operation, and the backwashing liquid (quenching water clear liquid and washing water clear liquid generated in the microchannel separator) is fed from the bottom backwashing inlet 40, and nitrogen (flow rate is 0.44Nm3 / h), after being evenly distributed by the fluid distributor 41 at the bottom, it passes through the particle bed from bottom to top, making the bed boiling. The nitrogen flows out through the exhaust port 42, and the regeneration liquid carries the filter material into the cyclone 39, so that the filter material particles are washed in the cyclone field, strengthening the regeneration of the filter material, and recovering the filter material particles at the same time. The pollutants are discharged from the discharge port 53 along with the liquid phase. The water consumption of the backwash liquid for the device with a processing capacity of 50L / h is 0.056m 3 / h. For a device with a processing capacity of 50 cubic meters, the regeneration water consumption is 50 cubic meters per hour.

[0094] 4. Results Analysis

[0095] Through the purification effect of the microchannel separator, the solid content of the stripping tower inlet water was reduced from 60mg / L to below 5mg / L, with a removal rate of more than 80%. The content of oily wax substances was reduced from 350mg / L to below 25mg / L, and the average operating pressure drop of the microchannel separator was 0.03MPa. During the test, after 300 hours of continuous operation and 20 backwashing regeneration operations, the initial separation effect was still maintained, and the separation efficiency exceeded 80%.

[0096] In addition, by using a microchannel separator to purify the inlet water of the methanol to olefins stripping tower, the separation accuracy is improved while avoiding the defects of the original fine filtration method, such as short operating cycle, incomplete regeneration, and low efficiency in removing oil and wax substances. Compared with the fine filtration method, this method has lower equipment cost and energy consumption.

[0097] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are within the spirit scope of the present invention.

Claims

1. A device for reducing the operating load of a methanol to olefins stripping tower, characterized in that: The device comprises a quench tower, a water washing tower, a microchannel separator and a stripping tower; The quenching tower is used to use quenching water to wash and cool the product gas generated from the methanol to olefins process to obtain quenched product gas and quenching water turbidity; and the quenching tower is provided with a quenching water turbidity circulation pipeline for circulating part of the quenching water turbidity into the quenching tower for use as the quenching water; The water washing tower is connected to the quenching tower, and the water washing tower is used to use washing water to wash and cool the quenched product gas again to obtain washed product gas and washing water turbidity; Furthermore, the water washing tower is provided with a water washing liquid circulation pipeline for circulating part of the water washing liquid into the water washing tower for use as the water washing water; The microchannel separator is connected to the quenching tower, and is used to receive part of the quenching water turbidity and remove particulate matter and part of organic matter therein to obtain quenching water clear liquid; and the microchannel separator is connected to the water washing tower, and is used to receive part of the washing water turbidity and remove particulate matter and part of organic matter therein to obtain washing water clear liquid; The stripping tower is in communication with the microchannel separator and is used to receive and process the quench water supernatant and the wash water supernatant to obtain purified water; The microchannel separator comprises a tower body, wherein the tower body is provided with a feed channel for introducing the quenched water turbid liquid and the water-cooled water turbid liquid, a filter material filling area for filling filter material, and a clear liquid containing chamber for containing the quenched water clear liquid and the water-cooled water clear liquid; The feed channel comprises a liquid outlet section inserted into the filter material filling area, the filter material filling area surrounds the outer periphery of the liquid outlet section, and the liquid outlet section is provided with a plurality of liquid outlet holes communicated with the filter material filling area at intervals along its axial direction; The filter material filling area is located between the liquid outlet section of the feed channel and the clear liquid containing chamber, the clear liquid containing chamber is located at the periphery of the filter material filling area, and the clear liquid containing chamber is provided with a liquid inlet hole communicating with the filter material filling area; The clear liquid containing chamber is provided with a water outlet hole for discharging the water phase of the quenched clear water liquid and the water-cooled clear water liquid, and an oil outlet hole for discharging the oil phase of the quenched clear water liquid and the water-cooled clear water liquid; The microchannel separator is also provided with a cyclone outside, the cyclone comprises a cylindrical body and a conical body connected to the bottom of the cylindrical body, the side wall of the cylindrical body is provided with a material inlet, the top of the cylindrical body is provided with a material outlet, and the bottom of the conical body is provided with a regenerated filter material outlet; The tower body is provided with an overflow port communicating with the filter material filling area and a regenerated filter material inlet, the overflow port is communicated with the feed inlet of the cyclone, and the regenerated filter material inlet is communicated with the regenerated filter material outlet of the cyclone; a free space is reserved in the area above the filter material filling area in the tower body, the overflow port and the regenerated filter material inlet are both arranged on the side wall of the tower body corresponding to the free space, and the overflow port is located above the regenerated filter material inlet.

2. The device for reducing the operating load of a methanol to olefins stripping tower according to claim 1, characterized in that: The device also includes a sedimentation tank, which is connected to the quenching tower and is used to send part of the quenching water turbidity into the microchannel separator after sedimentation separation; and the sedimentation tank is connected to the water washing tower and is used to send part of the washing water turbidity into the microchannel separator after sedimentation separation.

3. The device for reducing the operating load of a methanol to olefins stripping tower according to claim 1, characterized in that: The device further comprises a first heat exchanger, a first air cooler, a second heat exchanger and a second air cooler. The turbid quenching water used as the quenching water is cooled by the first heat exchanger and the first air cooler in sequence and then sent to the quenching tower for use; and The washing water turbid liquid used as the washing water is cooled down by the second heat exchanger and the second air cooler in sequence, and then sent to the washing tower for use.

4. The device for reducing the operating load of a methanol to olefins stripping tower according to claim 1, characterized in that: The tower body is provided with a backwash inlet for introducing regeneration gas and backwash liquid into the filter material filling area.

5. The device for reducing the operating load of a methanol to olefins stripping tower according to claim 4, characterized in that: The backwash inlet is arranged below the filter material filling area; A distributor for acting on the regeneration gas and the backwash liquid is provided at the bottom of the filter material filling area, and the backwash inlet is connected to the distributor.

6. The device for reducing the operating load of a methanol to olefins stripping tower according to any one of claims 1 to 5, characterized in that: The microchannel separators are provided in plurality, and the plurality of microchannel separators are connected in parallel.

7. A method for reducing the operating load of a methanol to olefins stripping tower using the device according to any one of claims 1 to 6, characterized in that: The method includes: The product gas generated from the methanol to olefins process is sent to a quench tower for washing and cooling with quench water to obtain quenched product gas and quench water turbid liquid; The quenched product gas is sent to a water washing tower to be washed again and cooled with washing water to obtain washed product gas and washing water turbidity; Circulating part of the turbid quenching water to the quenching tower for use as the quenching water, and circulating part of the turbid washing water to the washing tower for use as the washing water; Sending part of the turbid quench water into a microchannel separator for treatment to remove particulate matter and part of organic matter in the turbid quench water to obtain clear quench water; sending part of the turbid washing water into a microchannel separator for treatment to remove particulate matter and part of organic matter in the turbid washing water to obtain a clear washing water; The quench water supernatant and the washing water supernatant are sent to a stripping tower for treatment to obtain purified water.

8. The method for reducing the operating load of a methanol to olefins stripping tower according to claim 7, characterized in that: The method further comprises: a part of the quenching water turbidity liquid and a part of the washing water turbidity liquid are sent to a microchannel separator after sedimentation separation; The turbid washing water used as the washing water is cooled and then sent to the washing tower for use; The turbid quenching water used as the quenching water is sent to the quenching tower for use after the temperature is reduced.

9. The method for reducing the operating load of a methanol to olefins stripping tower according to claim 7 or 8, characterized in that: The method further comprises: When the filter material in the microchannel separator needs to be regenerated, the quenching water turbid liquid and the water-cooling water turbid liquid are stopped from being fed into the microchannel separator for filter material regeneration, and the regeneration gas and the backwashing liquid are introduced into the filter material filling area of ​​the microchannel separator through the backwashing inlet to backwash the filter material in the filter material filling area and make the filter material filling area form a boiling state; The backwash liquid carries the filter material into the cyclone from the overflow port, and removes the particulate matter and organic matter from the quenched water turbid liquid and the water-cooled water turbid liquid attached to the filter material to obtain regenerated filter material. The regenerated filter material flows back from the regenerated filter material outlet to the filter material filling area, and the removed particulate matter and organic matter are discharged from the discharge port.

Images