CN113877486A

CN113877486A - Reaction oil gas quenching system and method

Info

Publication number: CN113877486A
Application number: CN202010635784.0A
Authority: CN
Inventors: 江盛阳; 吴雷; 余龙红; 段丹; 邱静薇
Original assignee: Sinopec Engineering Inc; Sinopec Engineering Group Co Ltd
Current assignee: Sinopec Engineering Inc; Sinopec Engineering Group Co Ltd
Priority date: 2020-07-03
Filing date: 2020-07-03
Publication date: 2022-01-04

Abstract

The invention relates to a reaction oil gas quenching system and a method, wherein a washing section and at least one self-cleaning section are arranged in a quenching tower, so that the removal rate of catalyst particles in oil gas is obviously improved, the long-period safe and stable operation of a subsequent product separation system is ensured, the setting number of the self-cleaning sections can be flexibly selected according to the reaction type, the device treatment capacity and the requirement of a downstream system on the catalytic amount of the oil gas, and the application range is wide; meanwhile, the washing liquid in the self-cleaning section is circulated in a large section, so that a filter and a cooler do not need to be arranged in each cleaning section, and the investment of the device is greatly reduced.

Description

Reaction oil gas quenching system and method

Technical Field

The disclosure relates to the field of reaction oil gas quenching in petrochemical industry, in particular to a reaction oil gas quenching system and a reaction oil gas quenching method.

Background

The low-carbon olefin (ethylene, propylene and butylene) and light aromatic hydrocarbon (benzene, toluene, o-xylene, m-xylene and p-xylene) are extremely important organic chemical basic raw materials and have wide application. Ethylene is used in large quantities for the production of polyethylene, vinyl chloride and polyvinyl chloride, ethylbenzene, styrene and polystyrene, ethylene-propylene rubber; widely applied to synthesizing ethanol, ethylene oxide, ethylene glycol, acetaldehyde, acetic acid, propionaldehyde, propionic acid and derivatives thereof and other basic organic synthesis raw materials; vinyl chloride, ethyl chloride and ethyl bromide can be prepared by halogenation; can also be used for preparing alpha-olefin by oligomerization, and further producing higher alcohol, alkylbenzene and the like. The most used amount of propylene is to produce polypropylene, and in addition, propylene can be used for preparing acrylonitrile, isopropanol, phenol, acetone, butanol, octanol, acrylic acid and esters thereof, propylene oxide, propylene glycol, epichlorohydrin, synthetic glycerin and the like, and is used for producing various important organic chemical raw materials, synthetic resins, synthetic rubbers, various fine chemicals and the like. Butenes are used primarily for the manufacture of butadiene and secondarily for the manufacture of methyl ethyl ketone, sec-butyl alcohol, butylene oxide, and butene polymers and copolymers; isobutene is mainly used for manufacturing butyl rubber, polyisobutylene rubber and various plastics. The light aromatic hydrocarbon end product is mainly used in the fields of synthetic resin, synthetic fiber, synthetic rubber, paint, dye, medicine and the like.

The production route of low-carbon olefin and light aromatic hydrocarbon with more abundant raw material sources is actively developed at home and abroad, the processes of producing ethylene and propylene by organic oxide under the action of a metal modified SAPO molecular sieve catalyst, producing light aromatic hydrocarbon by organic oxide under the action of a modified ZSM-5 molecular sieve catalyst, producing propylene and butylene by saturated light hydrocarbon (ethane, propane and butane) under the action of a tungsten catalyst and the like are widely regarded.

Organic oxides represented by methanol or dimethyl ether are mainly synthesized from coal or natural gas. The technology for producing ethylene and propylene by taking organic oxide as a raw material mainly comprises an MTO (methanol to olefin) and MTP (methanol to propylene) process, the technology for producing light aromatic hydrocarbon by taking organic oxide as a raw material mainly comprises an MTA (methanol to olefins) process, and the technology for producing low-carbon olefin by taking saturated light hydrocarbons such as ethane, propane, butane and the like as raw materials for catalytic dehydrogenation mainly comprises an ADHO process. The process of MTO, MTP, MTA, ADHO, etc. features that fluidized catalytic reaction-regeneration technology is adopted to make the organic oxide, saturated light hydrocarbon and other material contact fully with solid catalyst in the reactor and the material is catalytically converted into low carbon olefin or light arene under certain reaction condition. The reaction temperature of the process is up to 500-800 ℃, the reaction oil gas containing spent catalyst is subjected to multistage cyclone separator to recover catalyst fine powder, and after heat in the reaction oil gas is taken out by a heat exchanger, the reaction oil gas needs to be subjected to quenching and product separation to obtain liquid and gas products.

In conclusion, in the process of producing low-carbon olefin/light aromatic hydrocarbon by fluidized catalytic conversion of MTO, MTP, MTA, ADHO and the like, the temperature of reaction oil gas is still higher after dust removal and heat recovery, and more small-particle-size catalyst fine powder is carried, so that the dust removal efficiency is low; meanwhile, fine catalyst powder is brought into a downstream product separation system, so that downstream equipment and pipelines are easily blocked and abraded, and long-period safe and stable operation of the downstream system is seriously influenced.

Disclosure of Invention

The invention provides a reaction oil gas quenching system and a reaction oil gas quenching method, which aim to improve the quenching and dust removal efficiency of reaction oil gas, simultaneously recover catalyst fine powder carried by the reaction oil gas, reduce the catalyst loss of the whole device and save the operation cost.

To achieve the above objects, the present disclosure provides a reaction oil and gas quench system comprising a quench tower comprising a quench liquid inlet, a reaction oil and gas inlet, a clean oil and gas outlet, and a catalyst slurry outlet; the quenching tower sequentially comprises a washing section and at least one self-cleaning section from bottom to top; the washing section comprises a first spraying device; the self-cleaning section sequentially comprises a water collecting tank, a tower tray and a second spraying device from bottom to top, wherein the water collecting tank comprises a tank body, a liquid outlet and an air lifting hole positioned at the top of the water collecting tank; a liquid outlet of the water collecting tank is respectively communicated with inlets of the first spraying device and the second spraying device through pipelines, and inlets of the first spraying device and the second spraying device are formed into the quenching liquid inlet; the reaction oil gas inlet is positioned below the washing section, the clean oil gas outlet is positioned at the top of the quenching tower, and the catalyst slurry outlet is positioned at the bottom of the quenching tower; the catalyst slurry outlet is communicated with the inlet of the first spraying device through a pipeline.

Optionally, the system further comprises a filter located outside the quench tower; the catalyst slurry outlet is communicated with the inlet of the filter through a pipeline; and a filter residue outlet of the filter is communicated with a catalyst inlet of the reactor through a pipeline, and a filtrate outlet of the filter is respectively communicated with an inlet of the second spraying device and the outside through pipelines.

Optionally, in the washing section, the lower part of the first spraying device is further provided with a plurality of layers of herringbone baffles, the plurality of layers of herringbone baffles are arranged at intervals along the axial direction, and each layer of herringbone baffle comprises a plurality of herringbone baffles which are uniformly distributed on a radial plane; the number of layers of the multilayer herringbone baffle is 2-20, preferably 5-10;

and the lower part of the washing section is also provided with a reaction oil gas distributor, and the inlet of the reaction oil gas distributor is formed as the reaction oil gas inlet of the quenching tower.

Optionally, the lower part of the quenching tower is also provided with a stirring slurry ring, and the outlet of the stirring slurry ring is communicated with the catalyst slurry outlet;

the quenching tower further comprises a supplementary quenching liquid inlet which is arranged at the top of the quenching tower or communicated with the inlet of the second spraying device.

Optionally, the quench tower comprises 1-5 of the self-cleaning sections;

the tower tray is one or more of a sieve-mesh type flow-through tower tray, a grid plate type flow-through tower tray and a corrugated plate type flow-through tower tray; the first spray device and the second spray device each independently comprise a wear-resistant nozzle or a pipeline uniform opening; the filter is an automatic backwashing filter.

A second aspect of the present disclosure provides a method for quenching reaction oil and gas using the system of the first aspect of the present disclosure, the method comprising: reaction oil gas and quenching liquid from a reactor enter a quenching tower from the lower part and the upper part respectively and are in countercurrent contact in the tower; the oil gas sequentially passes through a washing section and at least one self-cleaning section from bottom to top, clean oil gas is obtained at the tower top, and catalyst slurry containing catalyst particles is obtained at the tower bottom; wherein a first portion of said catalyst slurry is fed to said first spraying means as a quench liquid for said wash section; and dividing the self-cleaning slurry led out from the bottom of the self-cleaning section into two parts, wherein one part of the self-cleaning slurry is sent to the second spraying device to be used as the quenching liquid of the self-cleaning section, and the other part of the self-cleaning slurry is sent to the first spraying device to be used as the quenching liquid of the washing section.

Optionally, filtering a second part of the catalyst slurry to obtain filter residue and filtrate; sending a first part of the filtrate out of the system, and sending a second part of the filtrate into the second spraying device to be used as a quenching liquid of the self-cleaning section, wherein the weight ratio of the second part of the filtrate to the first part of the filtrate is (0-20): 1; and returning the filter residue to the reactor as a recycled catalyst.

Optionally, the method further comprises: a third portion of the withdrawn catalyst slurry is returned to the bottom of the quench tower through an agitated slurry loop.

Optionally, step S1 further includes uniformly distributing the oil gas by a reaction oil gas distributor and then feeding the oil gas into the quenching tower;

step S1 further includes passing supplemental quench liquid into the self-cleaning section; the supplementary quenching liquid is one or more of fresh water, factory water, desalted water, deoxygenated water and purified water.

Optionally, the weight ratio of the first portion and the second portion of the self-cleaning slurry is 1: (1-50);

the superficial linear velocity of the quenching tower is 0.5-5m/s, preferably the superficial linear velocity is 0.8-3m/s, more preferably the superficial linear velocity is 1.0-2.0 m/s;

the weight ratio of the quenching liquid to the reaction oil gas entering the quenching tower is (0.5-10): 1, preferably, the weight ratio is (1-8): 1, more preferably, the weight ratio is (3-5): 1;

the temperature of the reaction oil gas is 100-300 ℃, and the temperature of the clean oil gas is 30-150 ℃.

According to the method, the washing section and the at least one self-cleaning section are arranged in the quenching tower, so that the removal rate of catalyst particles in oil gas is remarkably improved, the long-period safe and stable operation of a subsequent product separation system is ensured, the setting number of the self-cleaning sections can be flexibly selected according to the reaction type, the treatment capacity of a device and the requirement of a downstream system on the catalytic amount of the oil gas, and the application range is wide; meanwhile, the washing liquid in the self-cleaning section is circulated in a large section, so that a filter and a cooler do not need to be arranged in each cleaning section, and the investment of the device is greatly reduced.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is a schematic illustration of a reaction oil gas quench system in example 1 of the present disclosure;

FIG. 2 is a schematic diagram of a reaction oil gas quench system in example 2 of the present disclosure;

FIG. 3 is a schematic diagram of a reaction oil gas quench system in a comparative example of the disclosure.

Description of the reference numerals

1. Reactor 2, quench tower 3, quench tower bottom slurry pump 4, filter

5. Intermediate circulating pump 6 of quenching tower, circulating pump 7 at top of quenching tower, reaction oil gas heat collector

11. Herringbone baffle 121, first spraying device 122, second spraying device 13 and water collecting tank

14. Tray 15, slurry ring 16, demister 17, reaction oil gas distributor

100. Reactor outlet oil gas 101, reaction oil gas 102, catalyst slurry

103. Stirring slurry at the bottom of the tower 104, washing slurry at the lower section of the quenching tower returning to the tower 105, and throwing slurry outside the quenching tower

106. Returning the filtered slurry to the tower 107, throwing the filtered slurry out 108, and filtering the residues

109. 110 parts of liquid is pumped out from the middle section of the quenching tower, and the liquid returns to the middle section of the quenching tower from the cleaning section

111. Replenishing liquid 112 in the lower washing section of the quench tower and withdrawing liquid from the upper washing section of the quench tower

113. Quench tower upper segment self-cleaning segment tower return liquid 114 quench tower middle segment self-cleaning segment make-up liquid

115. Replenishing quenching liquid 116, cleaning oil gas

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

In the present disclosure, unless otherwise specified, directional words such as "upper, lower, left and right" are used with reference to the drawing plane of the corresponding drawing. "inner" and "outer" refer to the inner and outer contours of the respective components. The use of the terms first, second, and third do not denote any order or importance, but rather the terms first, second, and third are used to distinguish one element from another. In addition, when the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements, unless otherwise indicated.

As shown in fig. 1 and 2, a first aspect of the present disclosure provides a reactive oil and gas quenching system, which comprises a quenching tower 2, wherein the quenching tower 2 comprises a quenching liquid inlet, a reactive oil and gas inlet, a clean oil and gas outlet and a catalyst slurry outlet; the quenching tower 2 sequentially comprises a washing section and at least one self-cleaning section from bottom to top; the washing section comprises a first spraying device 121; the self-cleaning section sequentially comprises a water collecting tank 13, a tower tray 14 and a second spraying device 122 from bottom to top, wherein the water collecting tank 13 comprises a tank body, a liquid outlet and an air lifting hole positioned at the top of the water collecting tank 13; a liquid outlet of the water collecting tank 13 is respectively communicated with inlets of a first spraying device 121 and a second spraying device 122 through pipelines, and inlets of the first spraying device 121 and the second spraying device 122 are formed as quenching liquid inlets; the reaction oil gas inlet is positioned below the washing section, the clean oil gas outlet is positioned at the top of the quenching tower 2, and the catalyst slurry outlet is positioned at the bottom of the quenching tower 2; the catalyst slurry outlet is in communication with the inlet of the first spraying device 121 via a line.

In order to sufficiently recover the catalyst particles at the bottom of the quenching tower, according to the present disclosure, as shown in fig. 1 and 2, a slurry filter 4 may be provided outside the quenching tower 2; in one embodiment, the catalyst slurry outlet can be communicated with the inlet of the filter 4 through a pipeline, and the filter residue outlet of the filter 4 can be communicated with the catalyst inlet of the reactor 1 through a pipeline, so that the catalyst particles obtained by filtering can be sent back to the reactor 1 for recycling; in a further embodiment, the filtrate outlet of the filter 4 can be respectively communicated with the inlet of the second spraying device 122 and the outside through pipelines so as to send the first part of the filtrate out of the system, and the second part of the filtrate enters the quenching tower 2 through the inlet of the second spraying device 122 to be used as the quenching liquid of the self-cleaning section, thereby saving the consumption of the supplementary quenching liquid 115 and reducing the energy consumption of the device. The present disclosure is not limited to the form of the filter 4 and may be conventional in the art, and in one embodiment, the filter 4 may be an automatic backwash filter.

According to the different concentration of the catalyst in the reaction oil gas 101, the lower part of the first spraying device 121 of the washing section at the lower part of the quenching tower 2 can be an empty tower or can be provided with a plurality of layers of herringbone baffles so as to filter the catalyst particles in the oil gas in the washing section as much as possible; in one embodiment, as shown in fig. 1 and 2, a plurality of layers of herringbone baffles can be arranged at intervals along the axial direction, and each layer of herringbone baffle can comprise a plurality of herringbone baffles which are uniformly distributed on a radial plane; in a further embodiment, the herringbone baffles in the two adjacent layers of herringbone baffles can be distributed in a staggered mode, namely the projections of the herringbone baffles in the two adjacent layers of herringbone baffles on a radial plane are not overlapped or partially overlapped, so that the blocking and intercepting effect of the baffles on catalyst particles in rising oil gas is improved. Because the concentration of the catalyst in the slurry of the washing section of the quench tower 2 is highest, the fine catalyst powder carried by the reaction oil gas 101 has strong adhesiveness, and the phenomenon that a gas channel is easily blocked by the catalyst is caused by adopting a conventional tray or filler, the herringbone baffle is preferably adopted in the washing section of the lower section, and the advantages of large gas phase channel and low pressure drop of the herringbone baffle are utilized, so that the washing efficiency is improved, and the blockage of the gas phase channel is avoided; further preferably, the number of layers of the herringbone baffles may be 2 to 20 layers, and preferably may be 5 to 10 layers.

According to the present disclosure, as shown in fig. 1 and 2, in order to achieve uniform distribution of the reaction oil gas 101 on the inner tower section of the quenching tower 2, in a preferred embodiment, the lower portion of the scrubbing section may be further provided with a reaction oil gas distributor 17, and the inlet of the reaction oil gas distributor 17 may be formed as the reaction oil gas inlet of the quenching tower 2.

According to the present disclosure, as shown in fig. 1 and 2, in order to keep the high-concentration catalyst slurry 102 at the bottom of the quenching tower 2 in a turbulent state and reduce the clogging of the catalyst slurry outlet due to the catalyst accumulation and deposition at the bottom of the quenching tower, in one embodiment, the lower part of the quenching tower 2 may be further provided with a stirring slurry ring 15, and the outlet of the stirring slurry ring 15 may be communicated with the catalyst slurry outlet. The present disclosure is not limited to the specific type and operation mode of the slurry stirring ring 15, and in one embodiment, the circumference of the slurry stirring ring 15 may be provided with small holes uniformly distributed with openings facing vertically downward or obliquely downward, so that the catalyst slurry 102 is ejected vertically downward or obliquely downward, thereby disturbing the slurry at the bottom of the quench tower 2 and avoiding the deposition of catalyst particles.

In order to ensure the level stability of the bottoms and header tanks of the quench tower, as shown in fig. 1 and 2, the amount of quench liquid carried away by the reaction oil gas 101 or lost by the system can be compensated by adding a make-up quench liquid 115 in the quench tower 2, and in one embodiment, a separate make-up quench liquid inlet can be provided at the top of the quench tower 2; in another embodiment, the supplemental quench inlet can be in communication with the inlet of the second spray assembly to provide for replenishment of quench through the inlet of the second spray assembly.

According to the present disclosure, the number of self-cleaning sections in the quench tower 2 can be selected flexibly according to the upstream reaction type, the cyclone efficiency of the reaction system, the amount of dust carried by the reaction oil gas 101, and the requirement of the downstream system on the amount of catalyst contained in the oil gas, so as to reduce the investment of the device to the maximum extent, and in one embodiment, the quench tower 2 can comprise 1-5 self-cleaning sections. In order to further treat the oil gas at the outlet of the reactor with high catalyst dust content, reduce the catalyst content in the oil gas and reduce the abrasion of downstream equipment and pipelines, in a preferred embodiment, the quenching tower can comprise 1-5 self-cleaning sections.

According to the present disclosure, one or more layers of trays 14 may be included in the self-purging segment, the multiple layers of trays 14 may be spaced apart in the column space between the second sparger 122 and the header tank 13, and the number of trays 14 may range from 1 to 10. The tray 14 can be in the form of one or more of a sieve-hole flow tray, a grid plate flow tray and a corrugated plate flow tray, and in one embodiment, a sieve-hole flow tray with a self-cleaning function can be selected to avoid the blockage of the tower internals by catalyst fine powder, thereby being beneficial to reducing the pressure drop of the quench tower, improving the inlet pressure of a subsequent rich gas compressor and reducing the energy consumption of the device. After passing through the washing section of the quench tower 2, the concentration of catalyst fine powder in the circulating liquid of the middle-section self-cleaning section and the upper-section self-cleaning section is reduced section by section, so that the middle-section self-cleaning section and the upper-section self-cleaning section adopt a non-cross-flow type sieve tray-cross flow tray without a downcomer, and because the liquid holdup on the tray is low and the cleaning is convenient, the method is mainly used for the distillation process of easily polymerized compounds, and has good effect for scaling systems or equipment, such as systems containing a large amount of solid particles and mud and some corrosive systems. The open pores on the cross-flow tray have dual functions-gas and liquid phases pass through the pores, the whole tray consists of a bubbling area, and is different from a common cross-flow tray, a liquid descending area and a liquid receiving area are not arranged, and under the unified operation condition, the open pore ratio of the cross-flow tray is generally greater than that of a cross-flow sieve tray. The main disadvantage of flow-through trays is that the range of the high efficiency zone near flooding is very narrow, outside of which the efficiency drops very quickly. The purpose of the flow-through tray adopted by the method is not high in gas-liquid mass transfer efficiency, but that the gas forcibly passes through the liquid-holding tray to enable the liquid to be in a violent turbulent process, so that the catalyst powder deposited on the tray is stirred, washed and carried downwards, and the method has a remarkable self-cleaning effect. Therefore, flow-through trays are particularly suitable for the reactive oil gas quench process of the present disclosure.

The present disclosure is not limited to the form of the spray means within the washing and self-cleaning sections, and may be a matter of routine choice in the art, and in one embodiment, the first spray means 121 and the second spray means 122 each independently comprise a nozzle, preferably an abrasion resistant nozzle; in another embodiment, the spray lines may be in the form of spray lines, which may be uniformly provided with downwardly opening nozzles, and may be dendritic so that the spray liquid covers the entire cross-section of the quench tower 2.

According to the present disclosure, in an embodiment in which the first and

second spray devices

121 and 122 include nozzles, the first and

second spray devices

121 and 122 may each independently include a plurality of nozzles, and the plurality of nozzles may be uniformly distributed on a radial cross section on which the spray devices are located. The nozzle direction is preferably downwards, i.e. towards the tray below the sparger. For example, in one embodiment, the plurality of nozzles are uniformly spaced, for example, uniformly distributed in a circular area, and the liquid sprayed by the spraying device may be in a solid cone shape; in another embodiment, the plurality of spray holes are distributed around the circumference, and the liquid sprayed by the dilution spray device is in a hollow cone shape. In one embodiment, the sum of the total areas of the quenching liquid sprayed by all the nozzles covered on the herringbone baffle or the tray is more than 2 times of the sectional area of the quenching tower, so that the gas-liquid contact effect is ensured, and the dust removal efficiency is improved.

According to the present disclosure, the water collecting tank 13 may be used to collect the quenching liquid sprayed from the spray device above, the tank body of the water collecting tank 13 may be matched with the shape and size of the radial section of the tower, the tank body may collect the quenching liquid, the bottom of the tank body may be closed to store the quenching liquid, the bottom of the tank body may be provided with a liquid outlet for drawing the quenching liquid collected in the tank body from the side wall of the quenching tower 2; the tank body may be provided with a vertically through-going gas lift hole for allowing the reaction oil gas 101 from below the water collection tank 13 to enter the self-cleaning section through an outlet of the gas lift hole located above the water collection tank 13, and the number and size of the gas lift holes are not particularly limited.

According to the present disclosure, in order to prevent catalyst particles from blocking the clean oil gas outlet at the top of the quenching tower 2, as shown in fig. 1 and 2, a demister may be disposed at the top of the quenching tower 2 to reduce liquid drops and dust entrained by the quenched reaction oil gas 101; furthermore, the catalyst fines attached to the demister can be periodically washed with water, so as to reduce the amount of catalyst fines carried by the quenched reaction oil gas 101.

As shown in fig. 1 and 2, a second aspect of the present disclosure provides a method of quenching a reaction oil gas 101 using the system of the first aspect of the present disclosure, the method comprising: reaction oil gas 101 from a reactor 1 and a quenching liquid are respectively led into a quenching tower 2 from the lower part and the upper part and are in countercurrent contact in the tower; the reaction oil gas 101 sequentially passes through a washing section and at least one self-cleaning section from bottom to top, clean oil gas 116 is obtained at the tower top, and catalyst slurry 102 containing catalyst particles is obtained at the tower bottom; wherein a first portion of the catalyst slurry 102 is fed to a first spray device 121 as quench liquid for the wash section; the self-cleaning slurry led out from the bottom of the self-cleaning section is divided into two parts, wherein the first part of the self-cleaning slurry is sent to the second spraying device 122 to be used as the quenching liquid of the self-cleaning section, and the second part of the self-cleaning slurry is sent to the first spraying device 121 to be used as the quenching liquid of the washing section.

The reaction oil gas passes through the washing section and at least one self-cleaning section in the quenching tower, so that the removal rate of catalyst particles in the reaction oil gas is obviously improved, and the long-period safe and stable operation of a subsequent product separation system is ensured; meanwhile, the washing liquid in the self-cleaning section is circulated in a large section, so that a filter and a cooler do not need to be arranged in each cleaning section, and the investment of the device is greatly reduced.

According to the present disclosure, in order to recycle the catalyst fine powder carried by the reaction oil gas 101 to the reactor, reduce the catalyst consumption of the device, and significantly reduce the operation cost of the device, in one embodiment, as shown in fig. 1 and fig. 2, the second part of the catalyst slurry 102 may be filtered to obtain the filter residue 108 and the filtrate; in a further embodiment, the filter residue 108 can be returned to the reactor 1 as a recycled catalyst, a first portion of the filtrate can be sent out of the system, and a second portion of the filtrate can be sent to the second spraying device 122 as a quenching liquid in the self-cleaning section, so as to save the consumption of the supplementary quenching liquid 115; in a further embodiment, the weight ratio of the second portion of the filtrate to the first portion of the filtrate may be (0-20): 1, preferably may be (5-15): 1.

in accordance with the present disclosure, in order to maintain the turbulent state of the high concentration catalyst slurry 102 at the bottom of the quench tower 2, wherein the catalyst fines are not deposited in the slurry at the bottom of the tower to block the slurry outlet and lines at the bottom of the tower, in one embodiment, as shown in fig. 1 and 2, the method may further comprise: a third portion of the withdrawn catalyst slurry 102 is returned to the bottom of quench tower 2 through agitated slurry loop 15.

In accordance with the present disclosure, as shown in fig. 1 and 2, in order to achieve uniform distribution of the reaction oil gas 101 on the internal tower section of the quench tower 2, in a preferred embodiment, the step S1 may further include uniformly distributing the reaction oil gas 101 through the reaction oil gas distributor 17 and then into the quench tower 2.

In accordance with the present disclosure, as shown in fig. 1 and 2, in order to ensure the smooth liquid levels of the bottom and header tanks of the quench tower, the lost amount of quench liquid can be compensated by adding a make-up quench liquid 115 in the quench tower 2, in one embodiment, step S1 can further comprise introducing the make-up quench liquid 115 into the quench tower through a quench liquid inlet at the top of the quench tower 2, or introducing the make-up quench liquid 115 into the quench tower through a quench liquid inlet from the purge section; in a further embodiment, the supplemental quench liquid 115 can be one or more of fresh water, plant water, demineralized water, deoxygenated water, and purified water.

In accordance with the present disclosure, to achieve a large-scale circulation of each self-cleaning zone quench liquid to minimize catalyst concentration in the lower self-cleaning zone or wash zone quench liquid, in one embodiment, the weight ratio of the first portion and the second portion of the self-cleaning slurry can be 1: (1-50), preferably the weight ratio may be 1: (10-20).

The present disclosure is not limited to the quenching operation conditions, and in order to sufficiently achieve oil gas quenching and catalyst recovery, in one embodiment, the superficial linear velocity of the quenching tower may be 0.5 to 5m/s, preferably, the superficial linear velocity may be 0.8 to 3m/s, and more preferably, the superficial linear velocity may be 1.0 to 2.0 m/s; in a further embodiment, the weight ratio of the quenching liquid to the reaction oil gas 101 entering the quenching tower 2 can be (0.5-10): 1, preferably, the weight ratio may be (1-8): 1, more preferably, the weight ratio may be (3-5): 1; in a further embodiment, the temperature of the reaction oil gas 101 may be 100-: 1, the temperature of the clean-up oil and gas 116 may be 30-150 ℃, and preferably may be (40-80): 1, the heat in the oil gas is fully recovered on the basis of completing the processes of quenching and catalyst recovery in a quenching tower 2, and the heat loss is reduced.

According to the disclosure, the method has no special requirements for the applicable reaction oil gas 101, and the catalyst content can fluctuate in a large range, for example, the catalyst content in the reaction oil gas 101 can be 100-³。

The reactors for generating the oil gas include, but are not limited to, a reactor for preparing low-carbon olefins by fluidized catalytic conversion of organic oxides, a reactor for preparing aromatic hydrocarbons by fluidized catalytic conversion of organic oxides, and a reactor for preparing low-carbon olefins by fluidized catalytic dehydrogenation of hydrocarbons.

The present disclosure is further illustrated by the following examples, but is not to be construed as being limited thereby.

Example 1

The oil-gas quenching is carried out by adopting a Methanol To Olefin (MTO) reaction oil-gas three-section quenching system as shown in figure 1, and the system comprises a washing section and two self-cleaning sections. Specifically, the method comprises the following steps:

most of catalyst fine powder is removed from reaction oil gas 101 for preparing olefin from methanol through a multi-stage cyclone separator in a reactor 1, the temperature of the oil gas at the outlet of the reactor is 470 ℃, high-temperature-level heat is taken out through a reaction oil gas 101 heat collector 7, the temperature is reduced to 220 ℃, the reaction oil gas 101 enters a quenching tower 2 after heat taking, the reaction oil gas 101 is uniformly distributed on the section of the quenching tower 2 under the action of a reaction oil gas distributor 17, the linear speed of an empty tower of the quenching tower 2 is 1.25m/s, and the content of the catalyst fine powder in the reaction oil gas 101 is 500mg/m³。

The quenching tower 2 adopts a three-section washing process, the upper, middle and lower three-section washing adopts gas-liquid countercurrent contact, and the weight ratio (kg/kg) of all quenching liquid in the quenching tower 2 to reaction oil gas at the outlet of the reactor is 101-3.5: 1.

a washing section of the quenching tower 2 is arranged at the lower part of the quenching tower 2; the lower part of the quenching tower 2 is provided with 5 layers of herringbone baffles 11, and the bottom of the herringbone baffles is provided with a slurry stirring ring 15. In normal operation, the bottom slurry 102 of the quench tower 2 is pumped by the quench tower bottom slurry pump 3 and divided into three sections: first part of slurry 104 returning to the lower washing section of the quenching tower 2 is mixed with supplementary liquid 111 from the lower washing section of the quenching tower in the middle self-cleaning section of the quenching tower 2, and then returns to the lower part of the quenching tower 2, and is sprayed out through a wear-resistant nozzle to be in countercurrent contact with the reaction oil gas 101 for quenching and dust removal; the second part of quenching tower external slurry throwing 105 is sent to a water slurry filter 4, and catalyst fine powder carried in the slurry is filtered; the third portion of the bottom agitated slurry 103 is fed directly into the bottom agitated slurry loop 15. The liquid sprayed out by the wear-resistant nozzles of the washing section of the quenching tower 2 is in a 90-degree hollow cone shape, the washing section of the quenching tower is provided with 36 wear-resistant nozzles, and the wear-resistant nozzles are arranged at optimized positions, so that the sum of the total areas of the quenching liquid sprayed out by all the nozzles covered on the herringbone baffle is more than 2 times of the sectional area of the quenching tower. The clear solution after filtration through the filter 4 is divided into two parts: the filtered slurry 106 returning to the tower and the circulating liquid 113 returning to the top of the quenching tower are mixed and enter the top of the quenching tower 2 through a second spraying device 122 to be used as quenching liquid of a self-cleaning section, and the filtered slurry 107 is thrown out of the system; the weight ratio of the filtrate sent into the second spraying device 122 to the filtrate sent out of the system is 10: 1. and (3) conveying the catalyst filter residue 108 discharged by the water slurry filter 4 to the reactor 1, recovering catalyst fine powder, reducing the catalyst consumption of the device and reducing the operation cost. The water slurry filter 4 adopts an automatic back-flushing filter.

After the reaction oil gas 101 passes through the washing section at the lower part of the quenching tower 2, most of catalyst fine powder carried in the oil gas is washed, and in order to further reduce the catalyst content in the oil gas, the reaction oil gas 101 continuously flows upwards to enter the self-cleaning section at the middle part of the quenching tower. The middle self-cleaning section is arranged in the middle of the quenching tower 2; and 3 layers of flow-through

trays

14 and 1 water collecting tank 13 are arranged in the middle self-cleaning section, and a plurality of gas lifting holes are formed in the water collecting tank 13, so that the reaction oil gas 101 enters the middle self-cleaning section of the quenching tower through the gas lifting pipes and then is uniformly distributed on the cross section of the tower. During normal operation, the liquid 109 is pumped out from the middle section of the quenching tower from the middle section water collecting tank 13 by the middle circulating pump 5 of the quenching tower, and is divided into two parts: mixing a first part of middle-section tower return liquid 110 of the quenching tower with middle-section supplementary liquid 114 of the quenching tower from an upper-section self-cleaning section of the quenching tower 2, returning the mixture to the middle part of the quenching tower 2, spraying the mixture through a wear-resistant nozzle of a second spraying device 122, and carrying out countercurrent contact with the middle-section reaction oil gas 101 for quenching and dust removal; a second portion is sent to the first spray device 121 of the washing section of the quenching tower as washing section supplementary liquid 111; wherein the weight ratio of the first part to the second part is 1: (10-20); 2 middle sections of quench tower are from wear-resisting nozzle blowout liquid of cooling tower section 90 hollow taper type, quench tower middle section is from the cooling tower section and is set up 36 wear-resisting nozzle altogether, wear-resisting nozzle arranges the optimal position, guarantee that the blowout liquid toper is greater than 2 times after 2 middle sections of quench tower from the cooling tower section uppermost layer percolation tower tray projection area, guarantee quench liquid at tower cross-section evenly distributed, provide oil gas and quench liquid fully contact, quench liquid and the weight ratio that gets into reaction oil gas 101 in the tower are 4: 1.

the reaction oil gas 101 continues to flow upward into the upper portion of the quench tower. The upper self-cleaning section of the quenching tower 2 is arranged at the upper part of the quenching tower 2; the upper part of the quench tower 2 is provided with 3 layers of flow-through

trays

14 and 1 water collecting tank 13, and the water collecting tank 13 is provided with a plurality of riser holes, so that the reaction oil gas 101 enters the upper section of the quench tower from the cleaning section and is uniformly distributed on the cross section of the quench tower. During normal operation, the liquid 112 extracted from the upper section of the quenching tower is extracted from the upper section water collecting tank 13 by the quenching tower top circulating pump 6 and is divided into two paths: the upper-section self-cleaning section tower returning liquid 113 of the quenching tower is mixed with filtered tower returning slurry 106 from the lower-section washing section of the quenching tower 2 and external quenching tower top make-up water 115, then the mixture returns to the upper part of the quenching tower 2, and is sprayed out through a wear-resistant nozzle to be in countercurrent contact with the upper-section reaction oil gas 101 for quenching and dedusting; and the other path of the self-cleaning section replenishing liquid 114 in the middle section of the quenching tower is sent to the returning liquid 110 in the self-cleaning section in the middle section of the quenching tower. The upper section of the quench tower 2 is a hollow cone type with a 90-degree liquid spraying distance from wear-resistant nozzles in the self-cleaning section, the middle section of the quench tower is provided with 36 wear-resistant nozzles, and the wear-resistant nozzles are arranged at optimized positions, so that the sum of the total areas of the quench liquid sprayed by all the nozzles on the tray 4 is more than 2 times of the sectional area of the quench tower. The external supplementary quench liquid 115 adopts purified water stripped by a downstream product water stripper, and enters the quench tower 2 through a spray device of an upper self-cleaning section, so that water resources in the device are fully utilized, and the water consumption is reduced.

Because the self-cleaning liquid at the upper section of the quenching tower 2 contains a small amount of catalyst fine powder, in order to reduce the entrainment of liquid drops in the reaction oil gas 101 after quenching and the entrainment of catalyst dust, the top of the quenching tower 2 is provided with a baffle demister 16. In order to improve the efficiency of the demister 16, the catalyst fine powder attached to the demister 16 is periodically washed with water, and the amount of the catalyst fine powder carried by the quenched reaction oil gas 101 is reduced. The quenched oil gas 116 after quenching and dedusting has the temperature of 112 ℃ below zero and basically does not contain catalyst fine powder, and is sent to a downstream product separation system.

The content of the catalyst powder in the clean oil gas 116 obtained by the system and the method of the embodiment is 10mg/m³Removal rate of catalyst particles98 percent is reached.

Example 2

The oil gas quenching is carried out by adopting a Methanol To Olefin (MTO) reaction oil gas two-stage quenching system as shown in figure 2.

Example 2 differs from example 1 in that the oil and gas quench system comprises only two quench washes (one wash stage and one self-cleaning stage).

By adopting the reaction oil gas two-stage quenching system of the specific embodiment of the disclosure, the catalyst dust content in the reaction oil gas 101 at the outlet of the reactor is 300mg/m to 300mg/m³After two-stage washing of the quench tower, the content of catalyst powder in the clean oil gas 116 is less than 10mg/m³And the catalyst fine powder with the particle size of more than 10 mu m is completely removed, so that the abrasion of downstream product separation system equipment and pipelines is remarkably reduced. The catalyst filter residue 108 of the water slurry filter is sent to the reactor, so that the loss unit consumption of the catalyst of the reaction system can be reduced by about 25 percent, and the operation cost of the device is obviously reduced. The removal rate of the catalyst particles in the clean oil gas 116 obtained by the system and the method reaches 96.7 percent.

Comparative example

The oil gas quenching system for the Methanol To Olefin (MTO) reaction shown in FIG. 3 is adopted for oil gas quenching.

The comparative example differs from example 1 in that the quenching tower 2 is provided with only one washing stage at the lower part thereof, and the top of the washing stage is provided with wear-resistant nozzles, and the lower part thereof is provided with chevron-shaped baffles, and the bottom slurry is circulated back to the top of the washing stage by the quenching tower bottom slurry pump 3.

The clean oil gas 116 obtained by the system and method of the present example has a catalyst powder content of-50 mg/m³The catalyst particle removal rate was 83.3%.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A reaction oil gas quenching system, characterized in that the system comprises a quenching tower (2), wherein the quenching tower (2) comprises a quenching liquid inlet, a reaction oil gas inlet, a clean oil gas outlet and a catalyst slurry outlet;

the quenching tower (2) sequentially comprises a washing section and at least one self-cleaning section from bottom to top; the washing section comprises a first spraying device (121); the self-cleaning section sequentially comprises a water collecting tank (13), a tray (14) and a second spraying device (122) from bottom to top, wherein the water collecting tank (13) comprises a tank body, a liquid outlet and an air lifting hole positioned at the top of the water collecting tank (13); a liquid outlet of the water collecting tank (13) is respectively communicated with inlets of the first spraying device (121) and the second spraying device (122) through pipelines, and inlets of the first spraying device (121) and the second spraying device (122) are formed as the quenching liquid inlets;

the reaction oil gas inlet is positioned below the washing section, the clean oil gas outlet is positioned at the top of the quenching tower (2), and the catalyst slurry outlet is positioned at the bottom of the quenching tower (2); the catalyst slurry outlet is communicated with the inlet of the first spraying device (121) through a pipeline.

2. The system of claim 1, further comprising a filter (4) located outside the quench tower (2); the catalyst slurry outlet is communicated with the inlet of the filter (4) through a pipeline; and a filter residue outlet of the filter (4) is communicated with a catalyst inlet of the reactor (1) through a pipeline, and a filtrate outlet of the filter (4) is respectively communicated with an inlet of the second spraying device (122) and the outside through pipelines.

3. The system of claim 1, wherein in the washing section, a plurality of layers of herringbone baffles are further arranged at the lower part of the first spraying device (121), the plurality of layers of herringbone baffles are arranged at intervals along the axial direction, and each layer of herringbone baffle comprises a plurality of herringbone baffles which are uniformly distributed on a radial plane; the number of layers of the multilayer herringbone baffle is 2-20, preferably 5-10;

the lower part of the washing section is also provided with a reaction oil gas distributor (17), and the inlet of the reaction oil gas distributor (17) is formed as the reaction oil gas inlet of the quenching tower (2).

4. The system according to claim 1, wherein the lower part of the quenching tower (2) is further provided with an agitated slurry ring (15), the outlet of the agitated slurry ring (15) is communicated with the catalyst slurry outlet;

the quenching tower (2) further comprises a supplementary quenching liquid inlet which is arranged at the top of the quenching tower or communicated with the inlet of the second spraying device.

5. The system of any of claims 1-4, wherein the quench tower (2) comprises 1-5 of the self-cleaning sections;

the tray (14) is one or more of a sieve-hole type flow-through tray, a grid plate type flow-through tray and a corrugated plate type flow-through tray; the first spray device (121) and the second spray device (122) each independently comprise a wear resistant nozzle; the filter (4) is an automatic backwashing filter.

6. A method for quenching reaction oil gas by using the system of any one of claims 1 to 5, characterized in that the method comprises:

reaction oil gas (101) from a reactor (1) and a quenching liquid enter a quenching tower (2) from the lower part and the upper part respectively and are in countercurrent contact in the tower; the reaction oil gas (101) sequentially passes through a washing section and at least one self-cleaning section from bottom to top, clean oil gas (116) is obtained at the tower top, and catalyst slurry (102) containing catalyst particles is obtained at the tower bottom;

wherein a first portion of the catalyst slurry (102) is fed to the first spraying means (121) as quench liquid for the wash section;

and the self-cleaning slurry led out from the bottom of the self-cleaning section is divided into two parts, wherein the first part of the self-cleaning slurry is sent to the second spraying device (122) to be used as the quenching liquid of the self-cleaning section, and the second part of the self-cleaning slurry is sent to the first spraying device (121) to be used as the quenching liquid of the washing section.

7. The method according to claim 6, wherein the second portion of the catalyst slurry (102) is filtered to obtain a residue (108) and a filtrate; sending a first part of the filtrate out of the system, and sending a second part of the filtrate into the second spraying device (122) to be used as a quenching liquid of the self-cleaning section, wherein the weight ratio of the second part of the filtrate to the first part of the filtrate is (0-20): 1; and returning the filter residue (108) as a recycled catalyst to the reactor (1).

8. The method of claim 6, wherein the method further comprises: a third portion of the withdrawn catalyst slurry (102) is returned to the bottom of the quench tower (2) through an agitated slurry loop (15).

9. The method of claim 6, wherein step S1 further comprises distributing the reaction oil gas (101) uniformly through a reaction oil gas distributor (17) and into the quench tower (2);

step S1 further includes passing supplemental quench liquid (115) into the self-cleaning section; the supplementary quenching liquid (115) is one or more of fresh water, factory water, desalted water, deoxygenated water and purified water.

10. A process according to any one of claims 6 to 9, wherein the weight ratio of the first and second portions of the self-cleaning slurry is from 1: (1-50);

the superficial linear velocity of the quenching tower (2) is 0.5-5m/s, preferably the superficial linear velocity is 0.8-3m/s, more preferably the superficial linear velocity is 1.0-2.0 m/s;

the weight ratio of the quenching liquid to the reaction oil gas (101) entering the quenching tower (2) is (0.5-10): 1, preferably, the weight ratio is (1-8): 1, more preferably, the weight ratio is (3-5): 1;

the temperature of the reaction oil gas (101) is 100-300 ℃, and the temperature of the clean oil gas (116) is 30-150 ℃.