CN1974524A - Scraped falling film evaporator process for concentrating acrylamide solution - Google Patents
Scraped falling film evaporator process for concentrating acrylamide solution Download PDFInfo
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- CN1974524A CN1974524A CN 200610070644 CN200610070644A CN1974524A CN 1974524 A CN1974524 A CN 1974524A CN 200610070644 CN200610070644 CN 200610070644 CN 200610070644 A CN200610070644 A CN 200610070644A CN 1974524 A CN1974524 A CN 1974524A
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- film evaporator
- acrylamide
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Abstract
The present invention relates to concentration of acrylamide, and is especially scraped falling film evaporator process for concentrating acrylamide solution. The technological scheme includes the following steps: 1. regulating the vacuum degree of evaporating concentration system below 0.01 MPa; 2. opening the first section steam terminal valve and the second section terminal valve of the scraped falling film evaporator to regulate the pressure in 0.01-0.03 MPa and the temperature in 50-80 deg.c; and 3. preheating the low concentration water solution of acrylamide through the steam preheater to 30-40 deg.c before entering to the distributor of the scraped falling film evaporator, and concentrating the solution of acrylamide to 60-80 % concentration in the scraped falling film evaporator. The present invention introduces scraped falling film evaporator in concentrating acrylamide solution, and has low power consumption, low cost and other advantages.
Description
One, technical field:
The present invention relates to a kind of concentration method of acrylamide soln, particularly a kind of method with the scraped falling-film evaporator concentrating acrylamide solution.
Two, background technology:
Domestic acrylamide production is main in the past adopts traditional sulfuric acid hydration process and copper catalytic hydration, domesticly begins to research and develop microbial method from the eighties in 20th century and produces the acrylamide technology.At present domestic one have the manufacturing enterprise of tame acrylamide more than ten, all adopt microbial method, about 350,000 tons/year of aggregated capacity, actual ultimate production was nearly 200,000 tons in 2004.Fluidised bed drying is mainly adopted in the existing spissated production of acrylamide soln, and fluid bed drying process possesses skills complicated, and parameter control difficulty is bigger, and energy consumption is big, shortcomings such as facility investment is big, in addition, in use the shortcoming of thermo-sensitivity reaction easily takes place in acrylamide soln.
Three, summary of the invention:
Purpose of the present invention is exactly the above-mentioned defective that exists at prior art, provide a kind of and had that flow process is short, energy consumption is low, quality product is high, less investment, production cost be low, and overcome the method with the scraped falling-film evaporator concentrating acrylamide solution that the shortcoming of thermo-sensitivity reaction easily takes place for acrylamide soln in use.
Its technical scheme is: may further comprise the steps:
(1) regulate vacuum tightness in the evaporation concentration system make its maintain-below the 0.01MPa;
(2) open the epimere steam inlet valve and the epimere steam condensate outlet valve of scraped falling-film evaporator, and regulating the pressure size makes it be stabilized in 0.02-0.04MPa, opening hypomere steam inlet valve and condensation-water drain valve subsequently, regulating the pressure size and make it be stabilized in 0.01-0.03MPa to make that temperature is controlled at 50 ℃-80 ℃ in the vaporizer.
(3) the lower concentration acrylamide solution is preheating to 30-40 ℃ through vapor preheater, dominant discharge divides the two-way symmetry to enter the scraped falling-film evaporator divider at 350-550l/h, allow solution evenly enter scraped falling-film evaporator, and by scraper plate the aqueous solution is evaporated in that water surface of evaporation is film forming, it is 60%-80% that acrylamide soln is concentrated to concentration.
Wherein, the lower concentration acrylamide solution is preheating to 35 ℃ through vapor preheater.
The invention has the beneficial effects as follows: mainly contain and overcome existing acrylamide crystal to produce the energy consumption of producing acrylamide crystal in the concentration technology big, facility investment is big, shortcomings such as complex process; Scraped falling-film evaporator is being incorporated in the concentrated production of acrylamide first, it is low to have energy consumption, and facility investment is few, the high outstanding beneficial effect of technology purity simple to operation; Having overcome in use, the shortcoming that thermo-sensitivity reacts easily takes place in acrylamide soln.
Four, description of drawings:
Accompanying drawing 1 is the structural representation of scraped falling-film evaporator of the present invention.
Five, embodiment:
In conjunction with the accompanying drawings, the invention will be further described: may further comprise the steps:
(1) regulate vacuum tightness in the evaporation concentration system make its maintain-below the 0.01MPa;
(2) open the epimere steam inlet valve 1 and the epimere steam condensate outlet valve 2 of scraped falling-film evaporator 5, and regulating the pressure size makes it be stabilized in 0.02-0.04MPa, opening hypomere steam inlet valve 3 and hypomere condensation-water drain valve 4 subsequently, regulating the pressure size and make it be stabilized in 0.01-0.03MPa to make that temperature is controlled at 50 ℃-80 ℃ in the vaporizer.
(3) the lower concentration acrylamide solution is preheating to 35 ℃, open scraped falling-film evaporator solvent or diluent imported valve 6, dominant discharge divides the two-way symmetry to enter scraped falling-film evaporator at 350-550l/h, start scraped falling-film evaporator, by scraper plate the acrylamide dilute solution is formed film at the scraped falling-film evaporator internal surface and carry out evaporation concentration, it is 60%-80% that acrylamide soln is concentrated to concentration.
(4) open bottom concentrated solution discharging valve 7, discharging.
The technology of utilizing the scraped falling-film evaporator concentrating acrylamide solution is new process of production, by adjustment to the various technological production norms of scraped falling-film evaporator, overcome in use that the shortcoming of thermo-sensitivity reaction easily takes place acrylamide soln, thereby made scraped falling-film evaporator satisfy the needs of producing.Characteristics such as whole process of production has that flow process is short, energy consumption is low, quality product is high, less investment, production cost are low, this technology is promoting China's acrylamide industry to reduce dependence to foreign technology, encourage China's science and technology innovation, development of national industry that important role is arranged.
1, production principle
Material concentrated is the saturated vapor pressure difference according to each component in the mixing liquid, can adopt the method for conventional underpressure distillation at intermittence that they are separated one by one.But, for heat-sensitive substance, because the long decomposition that takes place easily in various degree of the residence time in batch still, cause distillage and yield to be affected, in this case, can consider to adopt falling-film evaporator, the material that contains heat-sensitive substance is distilled.In traditional falling-film evaporator, because the film forming thickness of material is inhomogeneous, the heat and mass effect is not very good, causes the vaporization efficiency in this falling-film evaporator not high, contains the more distillatory material that needs toward the contact meeting in the distillation residue.In order further to improve vaporization efficiency, can adopt scrapper thin film evaporator that the material that contains heat-sensitive substance is carried out evaporation concentration, degassing precipitation, distillation purification.
2, performance characteristics
(1) the less pressure-losses
Material is forced to be heated vaporization after the film forming through scraper plate, although have certain pressure drop the process of steam from hot face to external condenser,, make that the steam circulation area is bigger because the knifing system adopts open by design, similar to the routine distillation, have the less pressure-losses.
(2) heat transfer coefficient is big, vaporization efficiency is high
Because the film device of scraping of rotation spreads to uniform film with material at the evaporation cylinder inner surface, effectively reduces thermal resistance, and make light component be very easy to from material fractionation by distillation to come out; Because the liquid film between cylinder inner surface and the blade applicator is in violent turbulence state, the different component transmission in the material and all very efficient with the heat transmission of heating medium in the heating jacket; In addition,, make hot face be not easy coking, fouling, also help to increase overall heat transfer coefficient, improve vaporization efficiency because not stopping transport of the best bright finish of cylinder inner surface and blade applicator is moving.
(3) vaporization temperature is low
Under higher vacuum condition, the vaporization temperature of material can drop to very low, in addition, because it is very thin to be in the liquid film of turbulence state, heat transfer coefficient is big, make the temperature difference of medium of evaporation temperature of charge of cylinder inner surface and chuck less, therefore, compare with the routine distillation, under equal vacuum condition, the Heating temperature of rotary film evaporator can be lower, and the temperature of charge of the most close evaporation cylinder inner surface is also corresponding low, thereby, reduced the thermolysis and the thermopolymerization of heat-sensitive substance, effectively guarantee product quality.
(4) heated time is short
For rotary film evaporator, material becomes spiral to descend at the hot face of the dual function lower edge of gravity and blade applicator limited length, in vaporizer the residence time very short, be generally several seconds～tens seconds (parameter correlations such as the form of mean residence time and hot face length, blade applicator and the characteristic of material, thickness).Compare with the routine distillation, because the vaporization efficiency height, material need not just can reach required separation degree by distill repeatedly, and the heated time of material is short, has reduced the thermolysis and the thermopolymerization of heat-sensitive substance to a great extent.
(5) adaptability is strong, turndown ratio is big
Because rotary film evaporator has above performance characteristics, make its suitable treatment heat-sensitive material, in addition, LFE series rotary film evaporator can be according to arts demand, select different blade applicators, and scum dredger and bottom scraper plate can be set scraping on the film device, therefore, the also material of the easy bumping of suitable treatment and full-bodied material, even the material of the mobile extreme difference of heavy component.
Claims (2)
1, a kind of method with the scraped falling-film evaporator concentrating acrylamide solution is characterized in that: may further comprise the steps:
(1) regulate vacuum tightness in the evaporation concentration system make its maintain-below the 0.01MPa;
(2) open one section steam terminal valve and two sections steam terminal valves of scraped falling-film evaporator, and regulate the pressure size and make it be stabilized in 0.01-0.03MPa, make that temperature is controlled at 50 ℃-80 ℃ in the scraped falling-film evaporator;
(3) the lower concentration acrylamide solution is preheating to 30-40 ℃ through vapor preheater, dominant discharge divides the two-way symmetry to enter the scraped falling-film evaporator divider at 350-550l/h, allow solution evenly enter scraped falling-film evaporator, and by scraper plate the aqueous solution is evaporated in that water surface of evaporation is film forming, it is 60%-80% that acrylamide soln is concentrated to concentration.
2, the method with the scraped falling-film evaporator concentrating acrylamide solution according to claim 1, it is characterized in that: the lower concentration acrylamide solution is preheating to 35 ℃ through vapor preheater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610070644 CN1974524A (en) | 2006-12-02 | 2006-12-02 | Scraped falling film evaporator process for concentrating acrylamide solution |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610070644 CN1974524A (en) | 2006-12-02 | 2006-12-02 | Scraped falling film evaporator process for concentrating acrylamide solution |
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| CN1974524A true CN1974524A (en) | 2007-06-06 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101774879A (en) * | 2009-01-14 | 2010-07-14 | 上海宝钢化工有限公司 | Method for simultaneously extracting high-purity beta-methylnaphthalene and indole from coal tar |
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2006
- 2006-12-02 CN CN 200610070644 patent/CN1974524A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101774879A (en) * | 2009-01-14 | 2010-07-14 | 上海宝钢化工有限公司 | Method for simultaneously extracting high-purity beta-methylnaphthalene and indole from coal tar |
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