CN-121988171-A - Membrane extraction separator, operation method and application thereof, and MTO quenching water washing system and operation method based on membrane extraction separator

CN121988171ACN 121988171 ACN121988171 ACN 121988171ACN-121988171-A

Abstract

The invention belongs to the technical field of preparing olefin from methanol, and provides a membrane extraction separator, an operation method and application thereof, and an MTO quenching water washing system and an operation method based on the membrane extraction separator, wherein the membrane extraction separator comprises a shell, an inorganic membrane tube bundle and a partition plate; the shell comprises a cylinder body, sealing heads and an ultrasonic generator, wherein the sealing heads are respectively arranged at two ends of the cylinder body, the ultrasonic generator is positioned on the outer surface of the cylinder body, the inorganic membrane tube bundle is arranged in the cylinder body, and the partition plate comprises a first layer of partition plate and a second layer of partition plate. The invention adopts the extractor to realize the coupling of the material impinging stream mixing strengthening mass transfer, the inorganic membrane extraction separation and the ultrasonic strengthening microcosmic mass transfer process, realizes the efficient extraction and separation of heavy aromatic hydrocarbon and ketone substances in the water washing water, simultaneously avoids the direct contact of the extractant and the water washing water, greatly reduces the loss of the extractant, and avoids the technical problem that the COD of the water washing water is seriously out of standard and difficult to process due to the fact that the extractant enters the water washing water.

Inventors

BO DECHEN
YANG CHANGYU
ZHANG QINGTAO
CAO RONGHAO
DING XINYU
WANG HE

Assignees

辽宁石油化工大学

Dates

Publication Date: 20260508
Application Date: 20260403

Claims (10)

1. A membrane extraction separator, characterized in that the membrane extraction separator comprises a housing, an inorganic membrane tube bundle and a separator; the shell comprises a cylinder body, a sealing head and an ultrasonic generator; The two ends of the cylinder body are respectively provided with a sealing head, the ultrasonic generator is positioned on the outer surface of the cylinder; The inorganic membrane tube bundle is arranged in the cylinder; the separator includes a first separator and a second separator.
2. The membrane extraction separator of claim 1, wherein a feed channel is arranged in the center of a single seal head, one seal head is provided with a water washing inlet, and the other seal head is provided with a water washing outlet; the feed channels extend into the inorganic membrane tube bundle through the sealing heads, the centers of the two feed channels are symmetrically arranged, The surface of the circulating outer cylinder, which is close to the inlet of the feeding channel, is uniformly provided with round holes; the upper side and the lower side of the circulating outer cylinder are symmetrically provided with a first layer of baffle plates, the edge of the first layer of baffle plates is connected with the cylinder body, and the middle point of the first layer of baffle plates is provided with a notch; the first layer of partition board is provided with a second layer of partition board on one side far away from the circulating outer cylinder, the second layer of partition board is parallel to the first layer of partition board, the second layer of partition board is symmetrically arranged, and notches are formed in two ends, close to the sealing heads, of the second layer of partition board.
3. A method of operating a membrane extraction separator according to claim 1 or 2, characterized by the steps of: (1) The extractant enters the membrane extraction separator through the feeding channel, enters the first interlayer of the first layer of partition plate and the circulating outer barrel through the round hole of the circulating outer barrel after being impacted in the circulating outer barrel, and is transferred with the washing water through the inorganic membrane tube bundle; (2) The extractant in the first interlayer enters a second interlayer of the first layer of partition plates and the second layer of partition plates through a notch of the first layer of partition plates, is transferred to the washing water through an inorganic membrane tube bundle, and enters a third interlayer of the second layer of partition plates and the cylinder body through a notch of the second layer of partition plates; (3) The extractant and the washing water of the third interlayer are transmitted through the inorganic membrane tube bundles under the action of ultrasonic waves.
4. A method of operating a membrane extraction separator as claimed in claim 3 wherein in step (1) the extractant comprises aromatic esters, nitro-containing aromatics and benzene ring-containing ketones; the aromatic ester compound comprises one or more of dimethyl phthalate, diethyl phthalate and dioctyl phthalate; the aromatic compound containing nitro group contains one or more of o-nitrobenzol, o-nitroethylbenzene and o-nitropropylbenzene; the ketone compound containing benzene ring contains one or more of diphenyl ketone, diacetone and diphenyl acetone; The mass ratio of the aromatic ester compound to the aromatic compound containing nitro to the ketone compound containing benzene ring is 10-60:10-40:10-60; the inorganic membrane tube bundles in the membrane extraction separator are hydrophobic mesoporous inorganic ceramic extraction membranes, and the membrane pore diameter of the inorganic membrane tube bundles is 1-100 nm.
5. The method for operating a membrane extraction separator according to claim 3 or 4, wherein the volume ratio of extractant to water wash water in the membrane extraction separator is 0.5-5:1; the pressure difference between the water washing side and the extractant side is 0.01-0.3 MPa; In the step (3), the frequency of ultrasonic waves is 10-30 kHz, and the power of the ultrasonic waves is 100-2000W/t of water washing water.
6. Use of the membrane extraction separator of claim 1 or 2 in an MTO process.
7. The MTO quenching water washing system based on the membrane extraction separator is characterized by comprising a separation tower, a membrane extraction separator, a solvent regeneration tower, an oxide stripping tower, an osmotic gasification membrane group, a hydrogenation reactor, a gas-liquid separation tank and a product water stripping tower; the membrane extraction separator comprises a first membrane extraction separator and a second membrane extraction separator; the separation tower is respectively connected with the first membrane extraction separator and the second membrane extraction separator; The solvent regeneration tower is respectively connected with the first membrane extraction separator and the second membrane extraction separator; The first membrane extraction separator is connected with the oxide stripping tower; The oxide stripping tower is connected with the permeation gasification membrane group; The second membrane extraction separator is connected with the product water stripping tower; the permeation gasification membrane group is connected with a hydrogenation reactor, and the hydrogenation reactor is connected with a gas-liquid separation tank.
8. A method of operating a membrane extraction separator based MTO quench water wash system according to claim 7, comprising the steps of: (a) The product gas is mixed with water in a separation tower to obtain water washing water, and the water washing water in the middle section of the separation tower is introduced into a first membrane extraction separator to obtain first external throwing water washing water; (b) Introducing the first external water-throwing washing water into an oxide stripping tower to obtain a crude oxide, and separating the crude oxide in an osmotic gasification membrane group to obtain a concentrated oxide; (c) Introducing the concentrated oxide into a hydrogenation reactor for hydrogenation reaction to obtain a reaction product, and separating the reaction product in a gas-liquid separation tank to obtain a gas-phase product and a liquid-phase product; (d) And the second external water-throwing water enters a product water stripping tower to be separated to obtain byproduct heavy aromatic hydrocarbon, and the circulating extraction phases of the first membrane extraction separator and the second membrane extraction separator enter a solvent regeneration tower to be separated.
9. The method for operating an MTO quench water wash system based on a membrane extraction separator of claim 8, wherein in step (a), the top temperature of the separation column is 45-60 ℃ and the number of trays is 14-30 layers; the extraction temperature of the middle section of the separation tower is 82-92 ℃; The mass of water washing water introduced into the first membrane extraction separator is 10-50% of the mass of water washing water in the middle section of the separation tower; the bottom extraction temperature of the separation tower in the step (a) is 110-120 ℃; the mass of water washing water fed into the second membrane extraction separator is 10-50% of the mass of water washing water at the bottom of the separation tower; The number of tower plates of the oxide stripping tower in the step (b) is 20-70, and the pressure is 200-600 kPa; The concentration of the crude oxide in the step (b) is more than or equal to 70 percent; The operation pressure of the permeation side of the permeation vaporization membrane group in the step (b) is 5-30 kPa, and the water content in the vapor permeating through the permeation vaporization membrane group is more than or equal to 99.9%; the water content of the concentrated oxide in step (b) is less than or equal to 1%.
10. The method of operating a membrane extraction separator-based MTO quench water wash system of claim 9, wherein the pressure of the hydrogenation reaction in step (C) is 0.5 to 1mpa, the temperature is 80 to 150 ℃, and the space velocity is 0.1 to 5; The molar ratio of the concentrated oxide to the hydrogen is 1:1-50; The pressure of separation in the step (C) is 0.5-1 MPa, and the temperature is 40-60 ℃; The tower plate number of the product water stripping tower in the step (d) is 20-70; the pressure of separation in the step (d) is 200-600 kPa; In the step (d), the packing height of the solvent regeneration tower is 20-50 theoretical plates; In the step (d), the operation pressure of the solvent regeneration tower is 1-10 kPa, the reflux ratio is 1-10, the tower top temperature is 60-160 ℃, and the tower bottom temperature is 150-220 ℃.

Description

Membrane extraction separator, operation method and application thereof, and MTO quenching water washing system and operation method based on membrane extraction separator Technical Field The invention relates to the technical field of olefin preparation from methanol, in particular to a membrane extraction separator, an operation method and application thereof, and an MTO quenching water washing system and an operation method based on the membrane extraction separator. Background The methanol-to-olefin (MTO) process is a chemical process technology for producing low-carbon olefins such as ethylene, propylene and the like by taking methanol synthesized by coal or natural gas as a raw material and adopting a fluidized bed reaction form similar to a catalytic cracking device. The MTO process provides a new way to convert the raw materials (natural gas or coal) with low cost advantage into the products of high added value low carbon olefin ethylene and propylene. The main products of the MTO process are ethylene (C 2H4) and propylene (C 3H6), whereas traditionally the sources of ethylene and propylene have been primarily petroleum hydrocarbon steam cracking with the feed being primarily naphtha. The MTO process mainly comprises a reaction regeneration system, a quenching-washing system and an olefin separation system. The quenching-washing system of the MTO device mainly aims at washing catalyst dust, water as a reaction byproduct, unreacted methanol and heavy components and light components generated by side reaction in reaction gas, and on the other hand, utilizes the abundant heat of the MTO device to be coupled with an olefin separation unit so as to realize the purpose of energy recovery. The MTO device reaction process has certain heavy aromatic hydrocarbon and ketone substances to generate, the heavy aromatic hydrocarbon and ketone substances can enter into the water washing water in the product gas water washing temperature reduction process, and the heavy aromatic hydrocarbon and ketone substances in the water washing water can be separated out to form wax substances to be attached to the surface of equipment in the water washing water heat exchange temperature reduction process, so that a system tower and a heat exchanger are blocked, and the long-period stable operation of the device is severely restricted. Therefore, the method for effectively removing the heavy aromatic hydrocarbon and ketone substance components in the gas-water washing water of the MTO product has great significance for long-period stable operation of the quenching water washing system. In addition, the light components generated by side reaction and a trace amount of unreacted methanol can also enter water washing water, and the concentration and recycling of the light components can improve the product yield and reduce the difficulty of treating the water washing water discharged from outside through a reasonable process. CN105419861a provides a separation device for heavy hydrocarbons, heavy oils and oxygen-enriched water in the MTO process. Wherein a heavy hydrocarbon flash tank is added before the oxide stripping tower, the liquid phase after flash evaporation enters an oil-water separation tank, the oil products after separation are sent to a C6 storage tank, and the water phase is sent to the oxide stripping tower for oxide recovery. The process method has the advantages that 1) the steam consumption of the stripping tower is large, the energy consumption is high, and 2) part of high-boiling wax cannot be completely removed, so that pipelines and equipment are easy to be blocked, and the wax is carried into a compressor water washing-alkaline washing system along with olefin and affects the stable operation of subsequent devices. CN110724024a provides a method and apparatus for removing wax from MTO product gas, the method uses one or more of xylene, ethylbenzene and toluene as extractant, and uses liquid-liquid extraction process in extraction tower to remove heavy hydrocarbon substances in water. The method has the problems that 1) the aromatic hydrocarbon such as dimethylbenzene, ethylbenzene and toluene is used as an extractant, the solubility of the material in water is high, on one hand, the extractant is seriously lost, and further the cost is high, on the other hand, the COD of the external drainage washing water is greatly increased, and the subsequent treatment is difficult, and 2) the boiling point difference between the material such as dimethylbenzene, ethylbenzene and toluene and the hydrocarbon material in the washing water is small, the separation is difficult, and the extractant is difficult to regenerate and has high energy consumption. Disclosure of Invention The invention aims to solve the problems that in the cooling process of water washing water of a quenching water washing system of an MTO device, a tray, a heat exchanger and a pipeline are blocked due to wax formed by precipitation of heavy aromat