CN105439904A - An acrylonitrile absorbing method - Google Patents
An acrylonitrile absorbing method Download PDFInfo
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- CN105439904A CN105439904A CN201410428907.8A CN201410428907A CN105439904A CN 105439904 A CN105439904 A CN 105439904A CN 201410428907 A CN201410428907 A CN 201410428907A CN 105439904 A CN105439904 A CN 105439904A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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- Y02P20/50—Improvements relating to the production of bulk chemicals
Abstract
The invention relates to an acrylonitrile absorbing method, and mainly overcomes the problems in the prior art, such as high water consumption for absorption. According to a technical scheme adopted by the method, the method includes respectively feeding a gas-phase raw material stream (1) containing the acrylonitrile, and the like and a liquid-phase raw material stream (2) into the bottom and the middle of a first adsorption tower (1a); separating and discharging a gas-phase stream III (3) from the tower top; discharging an absorption liquid V (5) from the tower bottom of the first adsorption tower (1a); feeding the gas-phase stream III (3) into the bottom of a second adsorption tower (3a); discharging a gas-phase light component VIII (8) from the tower top of the second adsorption tower (3a) after absorption with lean water (7) and cold energy recovery in the second absorption tower (3a); discharging a tower bottom absorption liquid VI (6) of the second absorption tower from the tower bottom of the second absorption tower (3a); returning the tower bottom absorption liquid VI (6) of the second absorption tower to the tower top of the first absorption tower; and feeding the lean water (7) from the tower top of the second absorption tower. The problems are overcome by adoption of the technical scheme. The method can be used for industrial production of the acrylonitrile by propylene ammoxidation.
Description
Technical field
The present invention relates to the absorption process of the vinyl cyanide in process for production of acrylonitrile.
Background technology
Vinyl cyanide is a kind of important organic chemical industry's basic raw material, be mainly used to produce the Chemicals such as acrylic fibers, acrylonitrile-butadiene-styrene (ABS) plastics (ABS), polyacrylonitrile, acrylamide, paracril, its by-product acetonitrile is fine solvent and organic synthesis intermediate, coproduct hydrogen cyanic acid can make sodium cyanide nearby, or make acetone cyanohydrin, as the raw material of synthesize methyl acrylic acid.Process for production of acrylonitrile experience cyanoethanol method and acetylene method.At present, domestic and international production method main propylene ammoxidation method.In this technique, unstripped gas propylene, ammonia, air pass into fluidized-bed reactor with certain proportion from bottom and react, reaction heat soft water circulation and stress, and high pressure steam occurs, and after reaction, gas can obtain high-purity propylene nitrile through chilling, absorption, rectifying etc.
Vinyl cyanide absorptive unit is the main processes in acrylonitrile process.Because ammoxidation of propylene reaction is an individual long-pending iodine, reduces the carrying out that reaction pressure is conducive to vinyl cyanide main reaction, the once through yield that propylene is cured can be improved, require that acrylonitrile absorbing tower tower has the low feature of pressure drop for this reason.Meanwhile, prevent the cohesion absorbing polymkeric substance in water from blocking up tower.Patent CN1055917C discloses one and has that pressure drop is low, throughput is large, acrylonitrile absorbing tower that simultaneously can be anti-blocking.Document US363607 describes the technique reducing methacrylonitrile content in acrylonitrile product.In this technique, draw a part of logistics from vinyl cyanide heavy constituent gas stripping column tower reactor and return absorption tower medium position, by methacrylonitrile components vaporize in absorption tower of gas stripping column tower reactor enrichment, from absorption tower tower top emptying, thus reduce the content of methacrylonitrile in acrylonitrile product.Document US363608 describes the another kind of technique reducing methacrylonitrile content in acrylonitrile product.Document CN1153760C discloses a kind of process for production of acrylonitrile, and its improvements are that absorption tower adopts nozzle to provide the second absorption water.
In existing document or report, how the absorption technique problem of shorter mention vinyl cyanide, particularly under ensureing to absorb prerequisite up to standard containing cyanogen compound content in tail gas, improve absorption liquid acrylonitrile concentration, reduce the problem absorbing the water yield.
Summary of the invention
Technical problem to be solved by this invention there is the topic that acrylonitrile concentration in absorption liquid is low, the absorption water yield is large in previous literature, provides a kind of absorption process of new vinyl cyanide.Under ensureing to absorb prerequisite up to standard containing cyanogen compound content in tail gas, the method have acrylonitrile concentration in absorption liquid high, absorb the water yield little advantage.
For solving the problems of the technologies described above, the technical solution used in the present invention is as follows: the absorption process of vinyl cyanide, comprise the steps: the bottom and the middle part that enter the first absorption tower (1a) containing the phase feed logistics (1) of vinyl cyanide, acetonitrile, prussic acid and water and liquid phase feed logistics (2) respectively, isolate the gaseous stream III (3) containing vinyl cyanide, acetonitrile, prussic acid and water at tower top, discharge the absorption liquid V (5) containing vinyl cyanide, acetonitrile, prussic acid and water in the first absorption tower (1a) tower reactor.
Gaseous stream III (3) enters second absorption tower (3a) bottom, takes out second absorption tower tower bottoms VI (6) at second absorption tower (3a) through poor-water (7) absorption with after cold recovery at the bottom of the tower top outer exhaust phase light constituent VIII (8) of taking-up and tower; Second absorption tower tower bottoms VI (6) is back to the first absorption tower tower top; Described poor-water (7) inputs through second absorption tower tower top.
In technique scheme, the service temperature on the first absorption tower is preferably 3.0 ~ 40.0 DEG C.
In technique scheme, the working pressure preferable range on the first absorption tower is 0.02 ~ 0.08MPa.
In technique scheme, the theoretical plate number on the first absorption tower is preferably 5 ~ 30.
In technique scheme, the first absorption tower place liquid phase feed logistics feed entrance point preferable range is at 2 ~ 28 theoretical tray places.
In technique scheme, the service temperature preferable range of second absorption tower is 2.0 ~ 30.0 DEG C.
In technique scheme, the working pressure preferable range of second absorption tower is 0.01 ~ 0.07MPa.
In technique scheme, the theoretical plate number preferable range of second absorption tower is 7 ~ 35.
In technique scheme, the first absorption tower and second absorption tower independent preferably self filler tower, tray column or void tower, more preferably packing tower.
In technique scheme, described poor-water is preferably 1.5 ~ 3.0 with the weight ratio of the phase feed logistics entering the first absorption tower.
Pressure in the present patent application file all refers to gauge pressure.
Owing to adopting vinyl cyanide, acetonitrile, the prussic acid in double tower absorption technique absorption acrylonitrile quenching gas in the present invention, under ensureing to absorb prerequisite up to standard containing cyanogen compound content in tail gas, poor-water (absorption water) amount decreases, in absorption liquid, acrylonitrile concentration is improved, thus the energy consumption of the separation and purification making absorption liquid follow-up decreases.Prove to adopt technical scheme of the present invention through test, liquid vapour weight ratio is reduced to 1.83, and absorption liquid acrylonitrile concentration is increased to 6.41%wt, achieves good technique effect.
Accompanying drawing explanation
Fig. 1 is the first schematic flow sheet of the absorption process of vinyl cyanide of the present invention.
Fig. 2 is industrial acrylonitrile absorbing tower schematic diagram.
In Fig. 1,1 is the phase feed logistics from aftercooler, and 2 is the liquid phase feed logistics from aftercooler, and 3 is the top gaseous phase stream I II on the first absorption tower, 4 is the tower top charging on the first absorption tower, 5 is the first absorption tower absorption liquid V, and 6 is second absorption tower tower bottoms VI, and 7 is the absorption water (poor-water) inputting second absorption tower, 8 is outer exhaust phase light constituent VIII, 1a is the first absorption tower, and 2a is second absorption tower tower reactor extraction pump, and 3a is second absorption tower.
The technical process of Fig. 1 is as follows:
In ammoxidating propylene to prepare acrylonitrile production technique, except the gas after ammonia chilling is divided into phase feed logistics and liquid phase feed logistics after aftercooler cooling, except containing except vinyl cyanide, acetonitrile, prussic acid and a small amount of organism in phase feed logistics, also containing a large amount of carbonic acid gas, the light constituent such as nitrogen, water vapor, temperature is generally 20 ~ 45 DEG C, enter the bottom on the first absorption tower of the present invention, liquid phase feed logistics is the aqueous solution, uniform temp is contained, through being cooled to the middle part that about 10 DEG C enter the first absorption tower with phase feed logistics.(major part is water to the poor-water come from follow-up refined unit, containing a small amount of organic impurity) after heat exchange temperature adjustment (its temperature is generally 2 ~ 7 DEG C), second absorption tower tower top is entered as absorption water, with the absorption tail gas counter current contact risen in second absorption tower, (main component is carbonic acid gas to tail gas after absorption, nitrogen, water vapor etc.) arrange outward and carry out subsequent disposal, the vinyl cyanide that second absorption tower absorbs, acetonitrile, the organic aqueous solutions such as hydrogen propylhomoserin are through being pumped to the top on the first absorption tower, with the gas phase counter current contact risen in the first absorption tower, gaseous stream after absorption enters the bottom of second absorption tower, the vinyl cyanide that first absorption tower absorbs, acetonitrile, (Fu Shui > enters follow-up refined unit to the absorption liquids such as hydrogen propylhomoserin.
In Fig. 2,1 is the gaseous stream from aftercooler, and 2 is the liquid phase stream from aftercooler, and 7 is absorption tower absorption water (poor-water), and 8 is outer exhaust phase light constituent, and 1a is absorption tower.
Below by embodiment, the present invention is further elaborated.
Embodiment
In order to make object of the present invention, technical scheme and advantage clearly understand, the present invention is described with following specific embodiment further, but the present invention is limited to absolutely not these examples.
[embodiment 1]
By the schematic flow sheet of Fig. 1, from gas phase and liquid phase two bursts of logistics of aftercooler, enter bottom and the middle part on the first absorption tower respectively, poor-water enters the top of second absorption tower.The each composition flow rate of gas phase is: vinyl cyanide 5986.5 kgs/hr, acetonitrile 165.1 kgs/hr, 594.7 kgs/hr, prussic acid, 1401.6 kgs/hr, water, propenal 15.4 kgs/hr, carbon monoxide 360.9 kgs/hr, carbonic acid gas 1214.5 kgs/hr, oxygen 705.1 kgs/hr, nitrogen 32477.7 kgs/hr, 103.3 kgs/hr, propane, propylene 248.9 kgs/hr.The each composition flow rate of liquid phase is: vinyl cyanide 422.7 kgs/hr, acetonitrile 42.4 kgs/hr, 46.4 kgs/hr, prussic acid, 12275.5 kgs/hr, water, propenal 1.6 kgs/hr.Poor-water is 79250.6 kgs/hr.First absorbing tower top gas phase flow rate is 35289.9 kgs/hr, and wherein vinyl cyanide, acetonitrile, prussic acid flow are respectively 2.4 kgs/hr, 0.0002 kg/hr, 16.2 kgs/hr, enter bottom second absorption tower.The tower top temperature on the first absorption tower is 4.8 DEG C, and pressure is 0.029MPa, and bottom temperature is 32.4 DEG C, and feed entrance point is at middle part.
The tower top temperature of second absorption tower is 4.6 DEG C, and pressure is 0.014MPa, and bottom temperature is 4.6 DEG C.After absorbing, tower top absorbs tail gas and arranges outward, and flow is 35284.9 kgs/hr, wherein adds up to concentration to be 0.5ppm containing vinyl cyanide, acetonitrile, prussic acid.Second absorption tower tower bottoms flow is 79255.5 kgs/hr and enters the first top, absorption tower.
Poor-water is 1.83 with the phase feed logistics weight ratio entering the first absorption tower, and absorption liquid acrylonitrile concentration is 6.41%wt.
[embodiment 2]
With embodiment 1, only change absorption pressure, second absorption tower pressure is 0.044MPa, the other the same as in Example 1.First absorbing tower top gas phase flow rate is 35245.6 kgs/hr, wherein vinyl cyanide, acetonitrile, prussic acid flow be respectively 0.6 kg/hr, trace, 2.5 kgs/hr, enter bottom second absorption tower.The tower top temperature on the first absorption tower is 4.8 DEG C, and pressure is 0.059MPa, and bottom temperature is 32.6 DEG C, and feed entrance point is at middle part.
The tower top temperature of second absorption tower is 4.6 DEG C, and pressure is 0.044MPa, and bottom temperature is 4.6 DEG C.After absorbing, tower top absorbs tail gas and arranges outward, and flow is 35246.4 kgs/hr, wherein adds up to concentration to be 0.3ppm containing vinyl cyanide, acetonitrile, prussic acid.Second absorption tower tower bottoms flow is 79249.8 kgs/hr and enters the first top, absorption tower.
Poor-water is 1.83 with the phase feed logistics weight ratio entering the first absorption tower, and absorption liquid acrylonitrile concentration is 6.41%wt.
[embodiment 3]
With embodiment 1, only change liquid-gas ratio, poor-water is 89250.6 kgs/hr.The other the same as in Example 1.First absorbing tower top gas phase flow rate is 35276.4 kgs/hr, wherein vinyl cyanide, acetonitrile, prussic acid flow be respectively 1.0 kgs/hr, trace, 4.8 kgs/hr, enter bottom second absorption tower.The tower top temperature on the first absorption tower is 4.8 DEG C, and pressure is 0.029MPa, and bottom temperature is 29.7 DEG C, and feed entrance point is at middle part.
The tower top temperature of second absorption tower is 4.6 DEG C, and pressure is 0.014MPa, and bottom temperature is 4.6 DEG C.After absorbing, tower top absorbs tail gas and arranges outward, and flow is 35284.3 kgs/hr, wherein adds up to concentration to be 0.4ppm containing vinyl cyanide, acetonitrile, prussic acid.Second absorption tower tower bottoms flow is 89242.9 kgs/hr and enters the first top, absorption tower.
Poor-water is 2.06 with the phase feed logistics weight ratio entering the first absorption tower, and absorption liquid acrylonitrile concentration is 5.82%wt.
[comparative example]
By the schematic flow sheet of Fig. 2, from gas phase and liquid phase two bursts of logistics of aftercooler, enter bottom and the middle and lower part on absorption tower respectively, poor-water enters the top on absorption tower.The each composition flow rate of gas phase is: vinyl cyanide 5986.5 kgs/hr, acetonitrile 165.1 kgs/hr, 594.7 kgs/hr, prussic acid, 1401.6 kgs/hr, water, propenal 15.4 kgs/hr, carbon monoxide 360.9 kgs/hr, carbonic acid gas 1214.5 kgs/hr, oxygen 705.1 kgs/hr, nitrogen 32477.7 kgs/hr, 103.3 kgs/hr, propane, propylene 248.9 kgs/hr.The each composition flow rate of liquid phase is: vinyl cyanide 422.7 kgs/hr, acetonitrile 42.4 kgs/hr, 46.4 kgs/hr, prussic acid, 12275.5 kgs/hr, water, propenal 1.6 kgs/hr.Poor-water is 79250.6 kgs/hr.
The tower top temperature on absorption tower is 4.6 DEG C, and pressure is 0.014MPa, and bottom temperature is 27.5 DEG C.After absorbing, tower top absorbs tail gas and arranges outward, and flow is 35283.6 kgs/hr, wherein adds up to concentration to be 0.9ppm containing vinyl cyanide, acetonitrile, prussic acid.
Poor-water is 2.29 with the phase feed logistics weight ratio entering the first absorption tower, and absorption liquid acrylonitrile concentration is 5.34%wt.
Claims (10)
1. the absorption process of vinyl cyanide, comprises the steps:
Bottom and the middle part on the first absorption tower (1a) is entered respectively containing the phase feed logistics (1) of vinyl cyanide, acetonitrile, prussic acid and water and liquid phase feed logistics (2), isolate the gaseous stream III (3) containing vinyl cyanide, acetonitrile, prussic acid and water at tower top, discharge the absorption liquid V (5) containing vinyl cyanide, acetonitrile, prussic acid and water in the first absorption tower (1a) tower reactor;
Gaseous stream III (3) enters second absorption tower (3a) bottom, takes out second absorption tower tower bottoms VI (6) at second absorption tower (3a) through poor-water (7) absorption with after cold recovery at the bottom of the tower top outer exhaust phase light constituent VIII (8) of taking-up and tower; Second absorption tower tower bottoms VI (6) is back to the first absorption tower tower top; Described poor-water (7) inputs through second absorption tower tower top.
2. the absorption process of vinyl cyanide according to claim 1, is characterized in that the service temperature on the first absorption tower is 3.0 ~ 40.0 DEG C.
3. the absorption process of vinyl cyanide according to claim 2, is characterized in that the working pressure preferable range on the first absorption tower is 0.02 ~ 0.08MPa.
4. the absorption process of vinyl cyanide according to claim 2, is characterized in that the theoretical plate number on the first absorption tower is 5 ~ 30.
5. the absorption process of vinyl cyanide according to claim 4, is characterized in that the first absorption tower place liquid phase feed feed entrance point is at 2 ~ 28 theoretical tray places.
6. the absorption process of vinyl cyanide according to claim 1, is characterized in that the service temperature of second absorption tower is 2.0 ~ 30.0 DEG C.
7. the absorption process of vinyl cyanide according to claim 6, is characterized in that the working pressure of second absorption tower is 0.01 ~ 0.07MPa.
8. the absorption process of vinyl cyanide according to claim 6, is characterized in that the theoretical plate number of second absorption tower is 7 ~ 35.
9. the absorption process of vinyl cyanide according to claim 1, is characterized in that the first absorption tower and second absorption tower are independently selected from packing tower, tray column or void tower.
10. the absorption process of vinyl cyanide according to claim 1, is characterized in that described poor-water is preferably 1.5 ~ 3.0 with the weight ratio of the phase feed logistics entering the first absorption tower.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410428907.8A CN105439904B (en) | 2014-08-27 | 2014-08-27 | The absorption process of acrylonitrile |
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| CN201410428907.8A CN105439904B (en) | 2014-08-27 | 2014-08-27 | The absorption process of acrylonitrile |
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| CN105439904B CN105439904B (en) | 2018-07-17 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111905527A (en) * | 2020-07-07 | 2020-11-10 | 山西钢科碳材料有限公司 | Exhaust gas treatment system and treatment method thereof |
| CN112441943A (en) * | 2019-09-05 | 2021-03-05 | 中石油吉林化工工程有限公司 | Method for controlling PH in water circulation system in operation process of acrylonitrile device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3885928A (en) * | 1973-06-18 | 1975-05-27 | Standard Oil Co Ohio | Acrylonitrile and methacrylonitrile recovery and purification system |
| CN1201784A (en) * | 1997-06-06 | 1998-12-16 | 中国石油化工总公司 | Acrylonitrile absorbing tower |
| CN1305392A (en) * | 1998-06-15 | 2001-07-25 | 索罗蒂亚公司 | Process for recovery of olefinically unsaturated nitriles |
-
2014
- 2014-08-27 CN CN201410428907.8A patent/CN105439904B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3885928A (en) * | 1973-06-18 | 1975-05-27 | Standard Oil Co Ohio | Acrylonitrile and methacrylonitrile recovery and purification system |
| CN1201784A (en) * | 1997-06-06 | 1998-12-16 | 中国石油化工总公司 | Acrylonitrile absorbing tower |
| CN1305392A (en) * | 1998-06-15 | 2001-07-25 | 索罗蒂亚公司 | Process for recovery of olefinically unsaturated nitriles |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112441943A (en) * | 2019-09-05 | 2021-03-05 | 中石油吉林化工工程有限公司 | Method for controlling PH in water circulation system in operation process of acrylonitrile device |
| CN111905527A (en) * | 2020-07-07 | 2020-11-10 | 山西钢科碳材料有限公司 | Exhaust gas treatment system and treatment method thereof |
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| CN105439904B (en) | 2018-07-17 |
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