Dispersing device for quench tower catalyst of methanol-to-olefin device

Abstract

The utility model discloses a dispersing device for a quench tower catalyst of a methanol-to-olefin device, which comprises a quench tower, and is characterized in that the device comprises a middle circulating water washing loop, a middle circulating pump and a circulating water flow regulating valve which are sequentially connected from a middle outlet of the quench tower and return to the quench tower, the device further comprises a liquid medicine storage tank and a dosing metering pump, and a water dispersing agent in the liquid medicine storage tank is conveyed to an inlet of the middle circulating pump through the dosing metering pump. According to the dispersing device for the catalyst of the quench tower of the MTO device, the water dispersing agent is adopted on the circulating water washing loop in the middle of the quench tower to remove attached catalyst powder in time, tower tray blockage is avoided, and the solid content in circulating water is reduced, so that the catalyst removing efficiency is improved, and the differential pressure of the quench tower is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of methanol to olefin (MTO) device, specifically to a kind of methanol to olefin device in quench tower in the dispersion device of catalyst. BACKGROUND

[0002] Methanol to olefin (MTO) device, with methanol as raw material, production is mainly low carbon olefin such as ethylene and propylene.The process is that superheated methanol raw material is sent into reactor, and reaction occurs with catalyst in fast fluidized bed, and product gas with ethylene, propylene as target product is generated.The quench tower after reactor is necessary equipment for product gas to remove overheating, wash catalyst dust and neutralize acidic substance.

[0003] MTO device quench water long-term existence catalyst (mainly catalyst fine powder) cannot be removed thoroughly, which leads to the deposition of these solids in quench tower tray, pipeline elbow and other parts, and due to the condensation reaction of aldehyde ketone components contained in product gas under alkaline conditions to form polymers, it is easier to block the tray screen hole, downcomer and other positions under the mediation of catalyst fine powder, causing the difference pressure of quench tower to rise, damaging the operating conditions in the tower, unable to establish circulation, leading to poor washing and neutralization effect.The increase of catalyst content in quench water system and the destruction of acid-base balance intensify the corrosion of heat exchanger tube bundle, which brings hidden dangers to the safe and stable operation of MTO device.

[0004] MTO device quench tower is usually provided with three sections of circulating water washing, and in the actual operation process of device, if the catalyst in product gas is not removed well at the bottom of quench tower, the solid content in circulating water in middle and upper part of quench tower exceeds the design value, and the catalyst cannot be removed in middle and upper part of circulating water, with the increase of running time of device, catalyst powder will adhere to middle and upper tray of quench tower in the running process of quench water system, thereby causing the blockage of tray, affecting the washing effect, and even leading to the entry of catalyst powder into downstream system of quench tower, which seriously affects the long-period stable operation of device. SUMMARY

[0005] The utility model aims at providing a kind of dispersion device of MTO device quench tower catalyst, can solve the problem of catalyst powder adhesion in MTO device quench tower and the blockage of tray caused, improve catalyst removal efficiency, reduce the difference pressure of quench tower, and ensure the stable operation of device.

[0006] To achieve the above-mentioned purpose of the invention, the utility model adopts the following technical solutions:

[0007] A kind of methanol to olefin device quench tower catalyst dispersing device, including quench tower, it is characterized in that, the device includes middle part circulating water washing circuit, middle part circulating pump is connected in sequence from the middle part outlet of the quench tower, circulating water flow regulating valve returns the quench tower, the device also includes liquid medicine storage tank and dosing metering pump, the water dispersant in the liquid medicine storage tank is transported to the inlet of the middle part circulating pump by the dosing metering pump.

[0008] Further, the water dispersant can be selected from commonly used water dispersant, including silicate dispersant, phosphate dispersant, oxide dispersant etc., preferably phosphate dispersant, such as sodium hexametaphosphate, sodium polyphosphate, potassium tripolyphosphate etc.The water dispersant can peel off the attachment deposited on tray etc., and can be combined with catalyst powder, so that it is not easy to deposit and scale in tray etc.

[0009] In the device, water dispersant from liquid medicine storage tank is injected into the inlet of middle part circulating pump after being pressurized by dosing metering pump, enters quench tower through circulating water and soaks on tray, slowly peels off larger catalyst solidification on tray, disperses into smaller particles and discharges to downstream sewage system in quench water, so as to reduce catalyst powder attachment in quench tower, avoid tray blockage, and improve catalyst removal efficiency.

[0010] Further, the dosing metering pump is hydraulic diaphragm metering pump.

[0011] Further, the outlet of dosing metering pump is provided with pressure gauge; control outlet pressure at 0.4-0.6Mpa.

[0012] Further, the outlet of dosing metering pump is provided with back pressure valve.

[0013] Further, one-way valve is arranged on the outlet pipeline of dosing metering pump.

[0014] Further, the quench tower includes product gas inlet at bottom, product gas outlet at top, also includes bottom circulating water washing circuit and upper circulating water washing circuit.

[0015] Beneficial effects: the MTO device quench tower catalyst dispersion device, the middle part of the circulating water washing circuit adopts water dispersant to remove the attached catalyst powder in time, avoids the tray blockage, reduces the solid content in the middle and upper circulating water, so as to improve the catalyst removal efficiency, and reduces the differential pressure of the quench tower. The utility model can effectively improve the operation capacity of the methanol to olefin device quench tower, improve the washing removal efficiency of the catalyst particles in the product gas, reduce the occurrence rate of the tray blockage and damage caused by the catalyst particles, ensure the stable production operation of the device, and avoid economic loss caused by the shutdown of the device. The device improves the long-period stable operation capacity of the quench tower in the production process of ethylene and propylene products, and reduces the production cost of ethylene and propylene products. BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 is a structure schematic view of the MTO device quench tower catalyst dispersion device of the utility model;

[0017] Among them, 1 is a quench tower, 2 is a middle circulating pump, 3 is a circulating water flow regulating valve, 4 is a dosing pump, 5 is a liquid medicine storage tank, 6 is a pressure gauge, 7 is a check valve, 8 is a safety valve, 9 is a first gate valve, 10 is a back pressure valve, 11 is a second gate valve. DETAILED DESCRIPTION

[0018] The technical scheme of the utility model is further described in detail through specific embodiments, but it is necessary to point out that the following embodiments are only used for describing the content of the application and do not constitute the limitation to the protection scope of the utility model.

[0019] The methanol to olefin device quench tower 1 includes a product gas inlet at the bottom, a product gas outlet at the top, and the product gas is deheated, washed catalyst and neutralized in the acidic substances therein. The quench tower 1 is usually provided with three circulating water washing circuits, i.e. a bottom circulating water washing circuit, a middle circulating water washing circuit and an upper circulating water washing circuit, the bottom circulation is used for washing and removing the solid catalyst entrained in the product gas, and the middle and upper circulation is used for neutralizing the acidic substances in the product gas.

[0020] As Figure 1 , the middle circulating water washing circuit of the quench tower 1 is sequentially connected with the middle circulating pump 2, the circulating water flow regulating valve 3 and returns to the quench tower 1, according to the device of the utility model, further comprising a liquid medicine storage tank 5 and a dosing pump 4, the water dispersant in the liquid medicine storage tank 5 is delivered to the inlet of the middle circulating pump 2 by the dosing pump 4.

[0021] The water dispersant added in the liquid medicine storage tank 5 includes silicate dispersant, phosphate dispersant, oxide dispersant and the like, and is preferably phosphate dispersant, such as sodium hexametaphosphate, sodium polyphosphate, potassium tripolyphosphate and the like. The water dispersant is a surfactant containing high-efficiency cleaning and dispersing components, can continuously and slowly peel off the adherents or scales deposited in the equipment such as the tray and pipeline layer by layer, disperse in the quenching water, and maintain the stable pressure difference of the quenching water tower. For the fine catalyst powder in the quenching water, the cleaning and dispersing components of the water dispersant can combine with the fine catalyst powder, so that the fine catalyst powder is not easy to deposit and scale in the tray and the like. Meanwhile, the water dispersant also has the function of coalescence for the catalyst powder in the quenching water, can make the catalyst powder coalesce into larger particles, and at the same time, increase the density of the catalyst powder, so that the catalyst powder is more easily washed out from the bottom. After increasing the discharge, the catalyst concentration in the water can be reduced, so that the catalyst concentration in the quenching water system is greatly reduced, and the coalescence ability is lost.

[0022] The water dispersant is added into the middle part of the quenching tower 1 by the dosing pump 4 through the pipeline, wherein the dosing pump 4 is a hydraulic diaphragm metering pump, and the stroke of the dosing pump 4 can be adjusted to control the amount of the added liquid medicine. The bottom outlet of the liquid medicine storage tank 5 is connected to the dosing pump 4 through the second gate valve 11, the dosing pump 4 sequentially passes through the back pressure valve 10, the one-way valve 7 and the first gate valve 9, and is connected to the inlet of the middle part circulating pump 2. At the same time, the pressure gauge 6 and the safety valve 8 are arranged at the outlet of the dosing pump 4; the outlet pressure is controlled at 0.4-0.6Mpa by the pressure gauge 6, and the liquid medicine flowing out through the safety valve 8 returns to the liquid medicine storage tank 5.

[0023] The back pressure valve 10 can be adjusted to adjust the system pressure, ensure the stable outlet pressure of the dosing pump 4, reduce the pump load fluctuation, and prevent the system from being damaged due to overpressure.

[0024] The above-mentioned quenching tower catalyst dispersing device, the process of the middle part circulating water washing is briefly described as follows:

[0025] 1) The water dispersant liquid medicine is prepared in the liquid medicine storage tank 5 according to the requirements;

[0026] 2) The second gate valve 11 and the first gate valve 9 are opened, and the safety facilities such as the pressure gauge 6 and the safety valve 8 are put into use;

[0027] 3) According to the system pressure, the back pressure valve 10 is adjusted, and the pressure range is set to 0.4-0.6Mpa;

[0028] 4) The dosing pump 4 is checked, the stroke is adjusted to 0, the dosing pump 4 is started, the stroke of the dosing pump 4 is adjusted to inject the liquid medicine into the middle part circulating water washing circuit;

[0029] 5) After the liquid medicine is injected, the operation of the quenching tower 1 is observed, and the liquid medicine injection is added or stopped according to the circulation amount.

Claims

1. A methanol to olefins plant quench column catalyst dispersing device, comprising a quench column (1), characterized in that, The device comprises a middle part circulating water washing circuit, a middle part circulating pump (2) and a circulating water flow regulating valve (3) are connected in sequence from the middle part outlet of the quench tower (1) and return to the quench tower (1), the device further comprises a medicine liquid storage tank (5) and a medicine adding metering pump (4), and the water dispersant in the medicine liquid storage tank (5) is delivered to the inlet of the middle part circulating pump (2) by the medicine adding metering pump (4).

2. The methanol to olefins plant quench tower catalyst dispersing device according to claim 1, characterized in that, The water dispersant is selected from silicate dispersant, phosphate dispersant or oxide dispersant.

3. The methanol to olefins plant quench tower catalyst dispersal apparatus of claim 1, wherein, The medicine adding metering pump (4) is a hydraulic diaphragm metering pump.

4. The methanol to olefins plant quench tower catalyst dispersal apparatus of claim 1, wherein, A pressure gauge (6) is arranged at the outlet of the medicine adding metering pump (4); and the outlet pressure is controlled to be 0.4-0.6 Mpa.

5. The methanol to olefins plant quench tower catalyst dispersal apparatus of claim 1, wherein, A back pressure valve (10) is arranged at the outlet of the medicine adding metering pump (4).

6. The methanol to olefins plant quench tower catalyst dispersal apparatus of claim 1, wherein, A one-way valve (7) is arranged on the outlet pipeline of the medicine adding metering pump (4).

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