CN210729002U

CN210729002U - MTO device quench tower for improving catalyst washing efficiency

Info

Publication number: CN210729002U
Application number: CN201921359237.3U
Authority: CN
Inventors: 赵福涛; 周建红; 程军; 张飞; 赵彬; 袁鹏辉
Original assignee: Sinopec Zhongyuan Petrochemical Corp Ltd
Current assignee: Sinopec Zhongyuan Petrochemical Corp Ltd
Priority date: 2019-08-21
Filing date: 2019-08-21
Publication date: 2020-06-12
Anticipated expiration: 2029-08-21

Abstract

The utility model belongs to the field of methanol to olefin, in particular to an MTO device quench tower for improving the washing efficiency of catalyst, which comprises a quench tower body and a component arranged in the quench tower body, wherein the component comprises a swirl plate demister arranged at the top of the quench tower body, a transverse spray pipe is arranged below the rotary plate demister, a top circulation distributor is arranged below the spray pipe, and a nozzle is arranged on the top circulation distributor; a flow-through tower plate is arranged below the nozzle, and a 2-3 array type herringbone baffle is arranged below the flow-through tower plate; and a bottom pipeline of the quenching tower body is connected with a tower kettle pump. The utility model discloses can effectively improve the washing volume and the washing efficiency of catalyst in the quench tower, reduce because of quench water heat exchanger blocks up the expense of wasing the consumption to effectively reduced the consumption of methyl alcohol vaporization unit middling pressure steam, be worth popularizing and applying.

Description

MTO device quench tower for improving catalyst washing efficiency

Technical Field

The utility model belongs to methyl alcohol system alkene field, concretely relates to improve MTO device quench tower of catalyst washing efficiency.

Background

The methanol-to-olefin (MTO) device is a technological process for converting methanol into ethylene and propylene under the conditions of proper temperature and pressure by adopting a fluidized bed mode reactor under the action of a special molecular sieve catalyst.

After MTO feed methanol enters a reactor, the MTO feed methanol is contacted with a catalyst, and is reacted and converted under proper reaction conditions in a fluidized state to generate light olefins such as ethylene, propylene and the like. The conversion product process gas carries certain catalyst fine powder, gas-solid separation is carried out through a three-stage cyclone separator, most of the catalyst fine powder is recovered and returned to a catalyst bed layer through the three-stage cyclone separator, a small amount of the catalyst fine powder enters a quench tower along with the process gas through a process gas cooler, the quench tower is in countercurrent contact with water circulation to wash the catalyst carried in the process gas, and the phenomenon that the process gas carries the catalyst fine powder to enter a subsequent process and influence the long-period stable operation of the device is avoided as much as possible.

In the conventional design of an MTO device quench tower, process gas carrying catalyst enters from the bottom of the quench tower, flows through a double-row blade distributor, a herringbone baffle plate, filler and an upper circulation distributor from bottom to top to be in countercurrent contact with return water of the quench tower, a small amount of catalyst carried in washing products simultaneously reduces the temperature of the product gas, under the condition that the washing efficiency of the quench tower cannot meet the requirement, a small amount of catalyst can enter a separation tower along with the process gas, the catalyst can be washed in the separation tower, the pressure difference is high due to the blockage of a tray, the catalyst enters a quench water system and can also block a quench water heat exchanger, and the equipment inspection and maintenance cost and the device energy consumption are increased.

Disclosure of Invention

For solving the not high shortcoming of catalyst washing efficiency among the prior art quench tower, the utility model provides an improve MTO device quench tower of catalyst washing efficiency.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

an MTO device quench tower for improving the washing efficiency of a catalyst comprises a quench tower body and components arranged in the quench tower body, wherein the components comprise a swirl plate demister arranged at the top of the quench tower body, a transverse spray pipe is arranged below the swirl plate demister, a top circulation distributor is arranged below the spray pipe, and a nozzle is arranged on the top circulation distributor; a flow-through tower plate is arranged below the nozzle, and a 2-3 array type herringbone baffle is arranged below the flow-through tower plate; and a bottom pipeline of the quenching tower body is connected with a tower kettle pump.

Furthermore, the lower part of the quenching tower body is also provided with a double-row blade distributor.

Further, the number of the nozzles is 7, and each set comprises 2 nozzles.

Further, the number of the flow-through trays is 4.

Furthermore, the herringbone baffle is 6 layers, and a tooth-shaped outlet weir is arranged on the herringbone baffle.

Further, the tower kettle pump is connected with a reflux circulation pipeline.

Compared with the prior art, the utility model discloses following beneficial effect has:

the utility model discloses a set up top circulation distributor under the shower, will spray the preliminary dispersion of liquid, set up 14 hollow awl wear-resisting nozzles, further be the toper with the water atomization and scatter, form the form of similar water curtain to increase gas-liquid area of contact, improve the washing effect. The 6 layers of the 5-6-shaped herringbone baffles are changed into the 2-3-shaped herringbone baffles, although the total number of the baffles is reduced, the width of the baffles is increased, a larger gas-liquid contact area is provided, the gradient is reduced, the washing effect is further improved, and the tooth-shaped outlet weir is added on the baffles, so that the liquid flowing state is improved, the gas-liquid contact area is increased, and the washing strength is increased. The liquid phase load of tower cauldron is more stable, more is suitable for the gas-liquid contact characteristics of cross-flow column plate, consequently the utility model discloses set up 4 layers of cross-flow column plates, can form the liquid layer on the column plate, increase gas-liquid area of contact to avoid original packing layer to take place the channeling phenomenon, product gas passes through the packing layer fast, leads to contact time weak point, the poor phenomenon of washing effect. The utility model discloses the device is used the back, and the washing volume and the washing efficiency of quench tower catalyst every day all show the improvement, and the expense that switches consumption reduces because of quench water heat exchanger blocks up to effectively reduce the consumption of methyl alcohol vaporization unit middling pressure steam, be worth popularizing and applying.

Drawings

FIG. 1 is a block diagram of a quench tower of the present invention;

in the drawings, the reference numbers: 1 is the quench tower body, 2 is the shower, 3 is the nozzle, 4 are the through flow column plate, 5 are herringbone baffles, 6 are double-row blade distributors, 7 are top circulation distributor, 8 are the whirl board demister.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are presented herein only to illustrate and explain the present invention, and not to limit the present invention.

As shown in fig. 1, an MTO unit quench tower for improving catalyst washing efficiency includes a quench tower body 1 and a component disposed in the quench tower body 1, the component includes a cyclone plate demister 8 disposed at the top of the quench tower body 1, the cyclone plate demister 8 separates entrainment by centrifugal force generated by cyclone; the rotating plate demister 8 is provided with a transverse spraying pipe 2 below, the spraying pipe 2 divides spraying liquid into small streams to flow down, a top circulation distributor 7 is arranged below the spraying pipe 2, the top circulation distributor 7 further disperses the spraying liquid, nozzles 3 are arranged on the top circulation distributor 7, the number of the nozzles is 7, each set of the nozzles is 2, and the nozzles 3 can atomize water and disperse the water in a conical shape to form a similar water curtain, so that the gas-liquid contact area is increased, and the washing effect is improved. The lower part of the nozzle 3 is provided with 4 layers of flow-through tower plates 4, liquid layers can be formed on the flow-through tower plates 4, the gas-liquid contact area is increased, the phenomenon that the original filler is subjected to channeling is avoided, and the product gas quickly passes through the filler, so that the contact time is short and the washing effect is poor. Compared with the 6 layers of the 5-6 shaped herringbone baffles in the prior art, the number of the total baffles is reduced, but the width of the baffles is increased, a larger gas-liquid contact area is provided, the gradient is reduced, the washing effect is further improved, and the toothed outlet weir is added to the baffles, so that the liquid flowing state is improved, the gas-liquid contact area is increased, and the washing strength is increased. A double-row blade distributor 6 is arranged below the herringbone baffle 5, and product gas enters blades in the quench tower to play a role in distribution and diffusion and increase the gas-liquid contact area; the bottom pipeline of the quenching tower body 1 is connected with a tower kettle pump, the tower kettle pump is connected with a circulating pipeline, and the other end of the circulating pipeline is connected with a spray pipe at the top of the tower.

The utility model discloses a theory of operation is: the product gas of the reactor is cooled to 382 ℃ and 0.125Mpa by a product gas cooler, then cooled to 310 ℃ by a medium-pressure waste heat boiler, cooled to 220 ℃ by a low-pressure waste heat boiler, the product gas rich in ethylene and propylene enters the quench tower body 1 from a product gas inlet pipeline at the bottom of the quench tower body 1, reversely contacts with spray liquid from bottom to top by a regular double-row blade distributor 6 to reduce the temperature of the product gas, the product gas sequentially passes through 6 layers of 2-3 array herringbone baffles 5 and 4 layers of flow-through tower plates 4, then is separated from mist by a swirl plate demister 8, and finally is conveyed to a subsequent separation tower from a pipeline at the top of the tower. The purified water at the top is in countercurrent contact with the product gas from top to bottom, the washing catalyst falls to the tower kettle, one part of the washing catalyst is pressurized by a tower kettle pump and returns to the spray pipe 2 at the top of the tower through a circulating pipeline for recycling, and the other part of the washing catalyst enters a water slurry filtering system, is filtered to remove the catalyst and is then conveyed to an anaerobic sewage treatment system.

The comparative example is the existing MTO device quench tower, which is provided with a rotational flow plate demister, a spray pipe, a tower return distribution pipe and a distributor, 2 sections of packing layers, 6 layers of 5-6-shaped herringbone baffles and a double-row blade distributor in sequence from the top to the bottom of the tower.

In the comparative example, the catalyst entrained in the product gas in the quench tower was washed in the bottom of the tower and pumped to a slurry filtration system, the withdrawal was about 15t/h, the average solids content in the discharged slurry was 760mg/L over two months, the catalyst amount in the quench tower wash was 15 × 24 × 760/1000 ═ 273.6 kg/day, and the quench tower wash efficiency = catalyst run out per reactor day for the day wash of the quench tower × 100% = 273.6/397.1 × 100% = 68.9%. In this example, the MTO unit quench tower shown in fig. 1 was used, the discharge water slurry at the bottom of the quench tower was still 15t/h, the average solid content in the discharge water slurry for two months was 1058mg/L, the amount of catalyst for washing the quench tower was 15 × 24 × 1058/1000 ═ 380.88 kg/day, and the efficiency of washing the quench tower = catalyst for washing the quench tower × 100% = 380.88/397.1 × 100% = 95.9% of catalyst lost per reactor day. It can be seen that the amount of the catalyst washed by the quenching tower per day is increased from 273.6kg to 380.88kg, the washing efficiency of the quenching tower is increased from 68.9% to 95.9%, and the washing amount and the washing efficiency of the catalyst are both obviously improved.

In the comparative example, product gas of a quenching tower is washed and cooled and then enters a separation tower, washing water is in countercurrent contact with the product gas to provide energy for a quenching water user heat exchanger E-5005, the quenching tower is poor in catalyst washing effect, the quenching water carries more catalyst to cause heat exchanger blockage, the heat exchanger needs to be switched to E-5009 for cleaning, low-pressure steam is used for E-5009, about 434.5 tons is consumed for cleaning each time, the average cleaning time per month is 3.2 times, the price of the low-pressure steam is 120 yuan/ton, and the steam consumption cost due to heat exchanger blockage is about 3.2 x 434.5 x 120/10000=16.68 ten thousand yuan/month. In the embodiment, because the washing effect of the catalyst of the quenching tower is good, the quenching water carries less catalyst, the blocking frequency of the heat exchanger is greatly reduced, the heat exchanger is cleaned for 0.5 time on average every month, and the steam cost for blocking the heat exchanger is about 0.5 multiplied by 434.5 multiplied by 120/10000=2.6 ten thousand yuan/month. Therefore, the cost of steam consumption per month due to the blockage of the quenching water heat exchanger E-5005 during switching is reduced by 14.08 ten thousand yuan.

In the comparative example, product gas of a quenching tower is washed and cooled and then enters a separation tower, washing water is in countercurrent contact with the product gas to provide energy for a user heat exchanger E-2101 of the quenching water, the washing effect of a catalyst of the quenching tower is poor, the heat exchange effect of the E-2101 is poor due to the fact that the quenching water carries more catalyst, the temperature of a methanol gasification outlet needs medium-pressure steam to ensure, the consumption of the medium-pressure steam is about 37.75t/h, the price of the medium-pressure steam is 175 yuan/ton, and the consumption cost of the medium-pressure steam is about 175 x 37.75 x 24 x 30/10000=475.65 ten thousand yuan/month. In the embodiment, because the washing effect of the catalyst of the quenching tower is better, the quenching water carries less catalyst, the E-2101 heat exchange effect is better, the temperature of a methanol gasification outlet is increased, the consumption of medium-pressure steam is reduced by about 33.5t/h, the price of the medium-pressure steam is 175 yuan/ton, and the cost of the medium-pressure steam consumption is about 175 x 33.5 x 24 x 30/10000=422.1 yuan/month. The monthly cost of steam consumption reduction in methanol gasification units is therefore about 53.55 ten thousand dollars.

The foregoing is a more detailed description of the present invention that is presented in conjunction with specific embodiments, and it is not to be understood that the specific embodiments of the present invention are limited to these descriptions. To the ordinary skilled person in the technical field of the present invention, without departing from the concept of the present application, a plurality of simple deductions or replacements can be made, all of which should be considered as belonging to the protection scope of the present invention.

Claims

1. The MTO device quench tower capable of improving the catalyst washing efficiency comprises a quench tower body (1) and components arranged in the quench tower body (1), and is characterized in that the components comprise a swirl plate demister (8) arranged at the top of the quench tower body (1), a transverse spray pipe (2) is arranged below the swirl plate demister (8), a top circulation distributor (7) is arranged below the spray pipe (2), and a nozzle (3) is arranged on the top circulation distributor (7); a flow-through tower plate (4) is arranged below the nozzle (3), and a 2-3 array type herringbone baffle (5) is arranged below the flow-through tower plate (4); the bottom pipeline of the quenching tower body (1) is connected with a tower kettle pump.

2. The MTO unit quench tower with improved catalyst washing efficiency as claimed in claim 1, wherein the lower part of the quench tower body (1) is further provided with a double row blade distributor (6).

3. The MTO unit quench tower for improving catalyst wash efficiency according to claim 1, wherein the number of the nozzles (3) is 7 sets of 2.

4. The MTO unit quench tower for improving catalyst washing efficiency as claimed in claim 1, wherein the number of the flow-through trays (4) is 4.

5. The MTO unit quench tower for improving catalyst washing efficiency as claimed in claim 1, wherein the herringbone baffle (5) is 6 layers, and the herringbone baffle (5) is provided with a toothed outlet weir.

6. The MTO unit quench tower of claim 1, wherein the kettle pump is connected to a reflux recycle line.