CN210150737U

CN210150737U - Continuous rectification device of ammonia

Info

Publication number: CN210150737U
Application number: CN201920703408.3U
Authority: CN
Inventors: 林海; 张豪杰
Original assignee: ZHEJIANG TIANCHENG ENGINEERING DESIGN Co Ltd
Current assignee: ZHEJIANG TIANCHENG ENGINEERING DESIGN Co Ltd
Priority date: 2019-05-15
Filing date: 2019-05-15
Publication date: 2020-03-17
Anticipated expiration: 2029-05-15

Abstract

The utility model relates to an aqueous ammonia preparation and extraction technical field, set up the big problem of reboiler and condenser energy consumption alone to every rectifying column in the continuous rectification, the utility model provides a continuous rectification device of ammonia, including the raw materials storage tank that connects gradually, a heat exchanger, one-level rectifying column, second grade rectifying column, the product storage tank, one-level rectifying column bottom is equipped with reboiler one and impurity export, the top is equipped with the condenser, second grade rectifying column bottom is equipped with reboiler two and product storage tank, the top is equipped with the heat pump, one-level rectifying column top and second grade rectifying column intercommunication, second grade rectifying column top communicates the heat pump in proper order, reboiler two, the heat exchanger and set gradually the tail gas condenser behind the heat exchanger, the tail gas absorber, the recovery tank, the top intercommunication of tail gas condenser and second grade rectifying column. The utility model discloses the gaseous phase at second grade rectifying column top heats up the pressurization back through the heat pump, as the heat source of reboiler two, has effectively utilized rectifying column top steam waste heat, reduces the heat supply of reboiler, and is energy-concerving and environment-protective.

Description

Continuous rectification device of ammonia

Technical Field

The utility model belongs to the technical field of the aqueous ammonia preparation and draws technique and specifically relates to a continuous rectifier unit of ammonia is related to.

Background

Electronic grade ammonia is a main raw material of a microelectronic silicon nitride masking film, is an important raw material in the field of photoelectron, directly determines the brightness of a Light Emitting Diode (LED) according to the quality of the electronic grade ammonia, and has high price and low cost, and the economy of the LED is improved. The electronic grade ammonia is generally prepared by rectifying industrial grade liquid ammonia, and the raw materials are relatively cheap, so the production cost of the electronic grade ammonia mainly considers energy consumption. According to market situation, energy consumption in the production cost of electronic grade ammonia accounts for more than ten times of raw material expenditure, so how to reduce energy consumption in the production process is very important. For example, in the patent literature of China, "a process for producing ultrapure ammonia and a preparation method thereof", the publication No. CN102502701B, raw material ammonia is pressurized by a pump and enters a rectifying tower to remove impurities such as light components and part of water, the raw material ammonia enters an oil and water removal device after cold energy is recovered, most of water is further removed and enters a terminal purification device, and the gas ammonia after deep water removal and impurities is condensed and enters a product ammonia tank to obtain an ultrapure ammonia product. The invention has simple process flow, low investment and optimized system energy. But this utility model well raw materials ammonia is untreated directly gets into the rectifying column and detach light component and some water class impurity, and heavy ends impurity in the raw materials ammonia has increased the burden of rectifying column, still can block up the rectifying column, needs the technical structure of an ideal in view of the above problem of solving.

SUMMERY OF THE UTILITY MODEL

The utility model discloses an overcome in the continuous rectification every rectifying column and set up the problem that reboiler and condenser energy consumption are big alone, provide the continuous rectification device of ammonia, the reboiler that the heat supplied its bottom is taken out through the heat pump in the top of second grade rectifying column uses, has utilized steam waste heat, has reduced the energy consumption.

In order to achieve the above purpose, the utility model adopts the following technical scheme: a continuous rectification device of ammonia comprises a raw material storage tank, a rectification tower, a heat exchanger, a tail gas condenser and a tail gas absorber, wherein a waste gas outlet is arranged on the tail gas absorber, the rectification tower comprises a primary rectification tower and a secondary rectification tower, a reboiler I and an impurity outlet are arranged at the bottom of the primary rectification tower, the condenser is arranged at the top of the primary rectification tower, a reboiler II and a product storage tank are arranged at the bottom of the secondary rectification tower, a heat pump is arranged at the top of the secondary rectification tower, the raw material storage tank, the heat exchanger, the primary rectification tower, the secondary rectification tower and the product storage tank are, wherein the outlet of the heat exchanger is connected to the middle part of the first-stage rectifying tower, the top part of the first-stage rectifying tower is communicated with the second-stage rectifying tower, the top part of the second-stage rectifying tower is sequentially communicated with the heat pump, the reboiler I, the heat exchanger, the tail gas condenser, the tail gas absorber and the recovery tank arranged behind the tail gas absorber, and the tail gas condenser is also communicated with the top part of the second-stage rectifying tower.

Industrial-grade liquid ammonia flows out from a raw material storage tank, is heated by a heat exchanger and then enters the middle part of a first-stage rectifying tower, impurities such as water, oil, metal and the like are removed in the first-stage rectifying tower, one part of the industrial-grade liquid ammonia serving as a gas phase is cooled by a condenser and then flows back to the first-stage rectifying tower, and the other part of the industrial-grade liquid ammonia enters a second-stage rectifying tower to be removed, wherein the H₂、N₂、O₂、CO、CO₂、CH₄And when impurities are contained, the electronic grade ammonia obtained at the bottom of the secondary rectifying tower flows into a product storage tank. The first-stage rectifying tower is arranged at the upper stream of the second-stage rectifying tower, and impurities such as water, oil and metal are discharged from the bottom of the first-stage rectifying tower, so that the blocking possibility of the subsequent second-stage rectifying tower and the reboiler II and the separation load of the second-stage rectifying tower can be reduced. And the gas phase at the top of the secondary rectifying tower is heated and pressurized by the heat pump and then flows to the reboiler II to be used as a heat source of the reboiler II, so that part of liquid in the reboiler II is vaporized, the waste heat of the steam at the top of the secondary rectifying tower is effectively utilized, the heat supply of the reboiler II is reduced, and the energy-saving and environment-friendly effects are achieved. And the gas phase flowing out of the heat pump supplies heat source to the reboiler II and then is further cooled by the heat exchanger and the tail gas condenser, the liquid phase flows back to the secondary rectifying tower, the gas phase goes to the tail gas absorber, the tail gas absorber absorbs redundant ammonia gas and stores the ammonia gas in the recovery tank, and other gases are discharged from a waste gas outlet arranged above the tail gas absorber.

Preferably, the first-stage rectifying tower and the second-stage rectifying tower are externally provided with insulating layers. The heat preservation layer can effectively reduce heat loss and save energy.

Preferably, a branch is arranged between the secondary rectifying tower and the product storage tank, a product cooler is arranged on the branch, one side of the product cooler is communicated with the bottom of the secondary rectifying tower through a valve, and the other side of the product cooler is communicated with the product storage tank. When the product temperature is too high and needs to be cooled, the first valve can be opened, and the high-purity ammonia at the bottom of the second-stage rectification tower is cooled by the product cooler to reach the proper temperature and then is discharged to the product storage tank.

As preferred, set up the product intermediate tank in front of the product storage tank, set up the purity detector on the product intermediate tank, set up the valve between product intermediate tank and the product storage tank. Because the product purity is higher, the product is firstly put into the product intermediate tank to be detected after being extracted from the bottom of the second-stage rectifying tower, and then is discharged into the product storage tank in batches after the purity is qualified.

Preferably, the first-stage rectifying tower and the second-stage rectifying tower are regular packing towers. The regular packing has small pressure drop and saves energy; the mass transfer and heat transfer efficiency is high, and the separation requirement of electronic grade ammonia can be met.

Preferably, a filter is arranged between the heat exchanger and the primary rectifying tower. The filter can filter out impurities such as oil in advance, and the separation load of the first-stage rectifying tower is reduced.

Preferably, the tail gas absorber is internally added with a ring saddle type filler, and a spraying device is adopted for tail gas absorption. The saddle-shaped packing has compact and symmetrical structure, the semi-annular fins in the saddle-shaped packing can increase the surface area of mass transfer and improve the mass transfer performance, and the saddle-shaped packing can be purchased; the sprayed water forms a mist film, further enhancing the absorption effect.

Therefore, the utility model discloses following beneficial effect has: (1) impurities such as metals in industrial-grade liquid ammonia which easily cause tower group blockage are removed in the first-stage rectifying tower in a centralized manner, so that the blockage possibility of a subsequent second-stage rectifying tower and a reboiler II and the separation load of the second-stage rectifying tower can be reduced; (2) the gas phase at the top of the secondary rectifying tower flows to the reboiler II after being heated and pressurized by the heat pump and is used as a heat source of the reboiler II, the waste heat of the steam at the top of the secondary rectifying tower is effectively utilized, the heat supply of the reboiler II is reduced, and the energy conservation and environmental protection are realized; (3) and heat-insulating layers are arranged outside the first-stage rectifying tower and the second-stage rectifying tower. The heat-insulating layer can effectively reduce heat loss and save energy; (4) a product intermediate tank is arranged in front of the product storage tank, and a purity detector is arranged on the product intermediate tank to ensure the purity of the product in the product storage tank.

Drawings

Fig. 1 is a schematic diagram of the present invention.

In the figure: 1. raw materials storage tank, 2, heat exchanger, 3, first-level rectifying tower, 4, condenser, 5, second-level rectifying tower, 6, product storage tank, 7, reboiler I, 8, valve I, 9, product cooler, 10, heat pump, 11, reboiler II, 12, tail gas condenser, 13, tail gas absorber, 14, recovery tank, 15, valve II, 16, product intermediate tank, 17, purity detector, 18, filter, 19, thermoscope.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description.

As shown in fig. 1, a continuous rectification apparatus for ammonia comprises a raw material storage tank 1, a heat exchanger 2, a primary rectification tower 3, a secondary rectification tower 5, a heat exchanger 2, a tail gas condenser 12, a tail gas absorber 13 and a recovery tank 14. Raw materials storage tank 1, heat exchanger 2, one-level rectifying column 3 and second grade rectifying column 5 communicate in proper order, and the industrial grade liquid ammonia that purity is 99.9% gets into heat exchanger 3 from raw materials storage tank 1, gets into from the middle part of one-level rectifying column 3 after the heating, takes off a part of impurity earlier, and this part of impurity is mainly water, a small amount is high boiling thing and metallic impurity etc. a little, and the gaseous phase of desorption impurity gets into second grade rectifying column 5 from the top of one-level rectifying column 3, another part of impurity of desorption, including H₂、N₂、O₂、CO、CO₂、CH₄And obtaining the electronic grade ammonia at the bottom of the secondary rectifying tower 5. The bottom of the first-stage rectifying tower 3 is provided with a first reboiler 7 and an impurity outlet, and impurities such as water, high-boiling residues, metal impurities and the like are discharged from the impurity outlet, so that the blockage of a subsequent second-stage rectifying tower 5 and a subsequent second reboiler 11 is reduced, and the separation load of the second-stage rectifying tower 5 is reduced; the top of the first-stage rectifying tower 3 is provided with a condenser 4, a part of gas phase is condensed by the condenser 4 and then flows back to the first-stage rectifying tower 3, and the other part of gas phase enters the second-stage rectifying tower 5. The bottom of the second-stage rectifying tower 5 is provided with a reboiler II 11 and a product storage tank 6, and the electronic-grade ammonia is extracted from the bottom of the second-stage rectifying tower 5Then flows into a product storage tank 6; the top of the second-stage rectifying tower 5 is provided with a heat pump 10, and the heat pump 10 is sequentially communicated with a second reboiler 11, the heat exchanger 2, a tail gas condenser 12, a tail gas absorber 13 and a recovery tank 14. The gas phase in the secondary rectifying tower 5 is heated and pressurized by the heat pump 10 and then passes through the reboiler II 11 as a heat source, so that part of liquid in the reboiler II 11 is vaporized, compared with the method that a condenser is arranged at the top of the secondary rectifying tower 5, the waste heat of the steam at the top of the secondary rectifying tower 5 is fully utilized, the steam supply of the reboiler II 11 is reduced, and the method is more energy-saving and environment-friendly. The gas phase flowing out of the heat pump 10 provides a heat source for the reboiler II 11, then is further cooled by the heat exchanger 2 and the tail gas condenser 12, the liquid phase flows back to the secondary rectifying tower 5, the gas phase goes to the tail gas absorber 13, the tail gas absorber 13 absorbs excess ammonia gas by water and stores the ammonia gas in the recovery tank 14, a waste gas outlet is formed in the upper portion of the tail gas absorber 13, and other gases are discharged from the waste gas outlet.

In order to effectively reduce heat loss and further save energy, the outsides of the first-stage rectifying tower 3 and the second-stage rectifying tower 5 are respectively provided with a heat insulating layer.

In order to cool the product, a branch is arranged between the secondary rectifying tower 5 and the product storage tank 6, a product cooler 9 is arranged on the branch, one side of the product cooler 9 is communicated with the secondary rectifying tower 5 through a valve I8, the other side of the product cooler is communicated with the product storage tank 6, a temperature detector 19 is arranged on a pipeline in front of the valve I8, if the temperature of high-purity ammonia extracted from the bottom of the secondary rectifying tower 5 is too high, the valve I8 can be opened, and the high-purity ammonia is cooled by the product cooler 9 to reach a proper temperature and then is discharged to the product storage tank 6.

In order to ensure the high purity of the product in the product storage tank 6, a product intermediate tank 16 is arranged in front of the product storage tank 6, a purity detector 17 is arranged on the product intermediate tank 16, the purity detector 17 for industrial-grade liquid ammonia is in the prior art, and a second valve 15 is arranged between the product intermediate tank 16 and the product storage tank 6. The product is extracted from the bottom of the secondary rectifying tower 5 and then stored in a product intermediate tank 16 for detection, and the product is put into a product storage tank 6 in batches after the purity is qualified. When the product fluctuation is abnormal, the product fluctuation can be detected in the product intermediate tank 16, the second valve 15 is closed in time, and the product storage tank 6 is prevented from being polluted by the product which does not reach the standard.

In order to improve the working stability of the rectifying tower, the primary rectifying tower 3 and the secondary rectifying tower 5 are structured packing towers, the pressure drop of the structured packing towers is small, and energy is saved; the mass transfer and heat transfer efficiency is high, and the separation requirement of electronic grade ammonia can be met.

In order to reduce the separation load of the primary rectifying tower 5, a filter 18 is provided between the preheater 2 and the primary rectifying tower 5. The filter 18 may filter out oil beforehand.

In order to enhance the absorption effect of the tail gas absorber 13, saddle-shaped packing is added in the tail gas absorber 13, the saddle-shaped packing is commercially available, the saddle-shaped packing has compact and symmetrical structure, and the semi-annular fins in the saddle-shaped packing can increase the mass transfer surface area and improve the mass transfer performance.

In order to further enhance the absorption effect, a spraying device is adopted in the tail gas absorber 13 to absorb the tail gas, and sprayed water forms a atomized film, so that the absorption effect is good.

Claims

1. A continuous rectification device of ammonia comprises a raw material storage tank (1) and a rectification tower, and is characterized by further comprising a heat exchanger (2), a tail gas condenser (12) and a tail gas absorber (13), wherein a waste gas outlet is formed in the tail gas absorber (13), the rectification tower comprises a first-stage rectification tower (3) and a second-stage rectification tower (5), a reboiler I (7) and an impurity outlet are arranged at the bottom of the first-stage rectification tower (3), a condenser (4) is arranged at the top of the first-stage rectification tower (3), a reboiler II (11) and a product storage tank (6) are arranged at the bottom of the second-stage rectification tower (5), a heat pump (10) is arranged at the top of the second-stage rectification tower (5), the raw material storage tank (1), the heat exchanger (2), the first-stage rectification tower (3), the second-stage rectification tower (5) and the product storage tank (6) are sequentially connected, wherein an outlet of the heat exchanger (2) is connected, the top of the second-stage rectifying tower (5) is sequentially communicated with a heat pump (10), a reboiler I (7), a heat exchanger (2), a tail gas condenser (12), a tail gas absorber (13) and a recovery tank (14) arranged behind the tail gas absorber (13), wherein the tail gas condenser (12) is also communicated with the top of the second-stage rectifying tower (5).

2. The continuous rectification plant for ammonia according to claim 1, characterized in that the primary rectification column (3) and the secondary rectification column (5) are externally provided with an insulating layer.

3. The continuous rectification device for ammonia according to claim 1, characterized in that a branch is arranged between the secondary rectification tower (5) and the product storage tank (6), a product cooler (9) is arranged on the branch, one side of the product cooler (9) is communicated with the bottom of the secondary rectification tower (5) through a valve, and the other side is communicated with the product storage tank (6).

4. The continuous rectification device for ammonia according to claim 1, characterized in that a product intermediate tank (16) is arranged in front of the product storage tank (6), a purity detector (17) is arranged on the product intermediate tank (16), and a valve is arranged between the product intermediate tank (16) and the product storage tank (6).

5. An apparatus for the continuous rectification of ammonia according to claim 1, 2 or 3, characterized in that the primary rectification column (3) and the secondary rectification column (5) are structured packed columns.

6. An apparatus for the continuous rectification of ammonia according to claim 1, characterized in that a filter (18) is arranged between the heat exchanger (2) and the primary rectification column (3).

7. An ammonia continuous rectification plant as claimed in claim 1, characterized in that a ring-saddle type packing is added in the tail gas absorber (13) and a spray device is used for tail gas absorption.