CN1090982C

CN1090982C - Continuous stirring vacuum sodium sulfate crystallization technology

Info

Publication number: CN1090982C
Application number: CN97106128A
Authority: CN
Inventors: 邵明福
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-10-10
Filing date: 1997-10-10
Publication date: 2002-09-18
Anticipated expiration: 2017-10-10
Also published as: CN1214272A

Abstract

The present invention relates to a weir continuous stirring vacuum sodium sulfate crystallization technology for recovering sodium sulfate in the production process of chemical fiber. Firstly, concentrating spinning bath liquid is pumped into a precooler to be precooled and then enters a multistage crystallizer to be crystallized into salt slurry; the concentrating spinning bath liquid is pumped into a thickening device to be thickened, and then the liquid-solid separation is carried out by a dewaterer; desalting mother liquid enters the crystallizer to be separated by crystallization by a degassing tank, and thickening mother liquid enters a bath liquid condenser by the other degassing tank; steam evaporated from the precooler is condensed, and simultaneously, the thickening mother liquid is directly heated; and the thickening mother liquid returns to a spinning bath slot to be circularly used after being heated up. The technology has the advantages of simple required equipment and low water consumption and energy consumption, and is favorable for environment protection.

Description

Continuous stirring vacuum sodium sulfate crystallization technology

The present invention relates to from liquid, isolate the technical field of fixed substance, more particularly relate to from spinning bath, remove in the rayon production technology of sodium sulfate by crystallization method.

In the chemical fibre industry production process of viscose fiber, alkaliferous viscose is under the volume pump effect, spray the spinning nozzle in spinning tank, carry out chemical reaction with sulfuric acid and generate fiber, acid-base neutralisation has generated a large amount of water and sodium sulfate, the constant component of spinning bath is changed, influence fiber quality.In order to stablize spinning condition, guarantee fiber quality, except constantly adding the vitriol oil and zinc sulfate, also need remove unnecessary sodium sulfate.At present, sodium sulfate is removed by chemical fibre producer from spinning bath processing unit mainly contains following two kinds: the continuous sodium chloride crystal machine of a kind of Ai Baina of being vacuum, " acid station " book (China Textiles Press publishes January nineteen ninety-five) 84-86 page or leaf that Shao Mingfu etc. write has been done detailed introduction to it, though this machine crystallization processes is reasonable, but its steam and water consumption are too high, influence economic benefit, particularly be not suitable for the poor area of water resources and adopt; Another kind is an anka saltcake vacuum crystallization machine, " regenerated fiber factory equipment " book that Huang Jiayu etc. write (press of Qingdao Marine University publishes in June, 1993) 368-369 page or leaf has been done more detailed elaboration to it, though this machine has overcome Ai Baina type crystallizer water consumption, the high shortcoming of consumption steam, but its whole set equipment complex structure, manufacture difficulty is big, the cost costliness.

It is low to the objective of the invention is to design a kind of water consumption power consumption cost low, equipment used, is used for chemical fibre industry is removed sodium sulfate from spinning bath sulfate crystal novel process.

Technical process of the present invention is as follows:

A, will concentrate spinning bath and in bath, carry out pre-cooledly the pre-cooler, bath temperature is reduced to below 32 ℃, enter then in the multi-stage mold (2) by being pumped into;

B, low temperature body lotion flow through multi-stage mold successively, crossing under the baffling stirring action of weir, spin upside down mobile Homogeneouslly-radiating, and temperature is reduced to below 18 ℃, go out sodium sulfate in the last step crystallization of multi-stage mold;

C, the salt slurry that crystallizes at the multi-stage mold last step, are fallen into water extracter and carry out liquid-solid separation to the enrichment device by pump delivery behind enrichment, degassing vessel is gone in the mother liquor overflow of enrichment device, and sucks in the body lotion condenser under vacuum action;

D, fall into the saltcake storehouse, and the desalination mother liquor enters another degassing vessel, enters the last step of multi-stage mold under vacuum action, carries out Crystallization Separation once more by the isolated sodium sulfate crystal grain of water extracter;

The steam that e, pre-cooler vacuum-evaporation go out enters in the body lotion condenser, and the low temperature mother liquor that is overflowed by the enrichment device carries out condensation, and the low temperature mother liquor obtains direct heating simultaneously, when its temperature rises to 37 ℃, gets back to the spinning tank internal recycle and uses;

Residual gas in f, the body lotion condenser and the vaporised gas in the multi-stage mold enter and are condensed into water in the off-gas condenser and enter in the pond of falling into water, uncooled residual gas enters drowning pond by steam jet pump and water jet pump again, simultaneously, the vacuum tightness of pre-cooler, body lotion condenser and multi-stage mold is also kept by off-gas condenser, steam jet pump and water jet pump.

The present invention compares with the existing sulfate crystal technology of chemical fibre industry, have following tangible advantage: the one, this technology is to utilize water jet pump suction water at low temperature steam, through off-gas condenser generation gas-liquid phase transition, water vapour nearly all is condensed into liquid state under 0 ℃ of temperature, water jet pump only aspirates residual vapor and incondensable gas, bear lighter, therefore many stainless steel steam jet pumps that involve great expense, mixing condenser, oil-sealed rotary pump and corresponding supporting utility appliance and valve pipe have been saved, thereby equipment used is simple and reliable for structure, greatly reduces cost; The 2nd, improved utilization to the heat that produces in producing, less energy consumption, working cost is low; The 3rd, water consumption is less, and the consumption steam is few, be particularly suitable for water resources and lack the area employing, and sewage flow rate is few, helps environment protection.Following table is that the benefit of technology of the present invention and existing Ai Baina and anka crystallization processes compares:

Technology type	Crystallizing power (t/h)	Water loss (m/h)	Current consumption (kwH)	Consume the freezing water yield (t/h)	Steam consumption (t/h)	Equipment used cost (ten thousand yuan)
Technology type	Crystallizing power (t/h)	Water loss (m/h)	Current consumption (kwH)	Consume the freezing water yield (t/h)	Steam consumption (t/h)	Equipment used cost (ten thousand yuan)	Ai Baina	4	384	70		0.523	250
Anka	4	100	100	165	0.113	500	Ai Baina	4	384	70		0.523	250
Anka	4	100	100	165	0.113	500	The present invention	4	80	40	68	0.02	100

Below in conjunction with drawings and Examples, the present invention is further described.

Accompanying drawing is a process flow sheet of the present invention.

The present invention is used for the recovery of viscose fiber production process sodium sulfate, also is applicable to the low temperature crystallization of yellow soda ash, sodium-chlor and other salt.Its technical process is as follows:

A, the concentrated spinning bath sent here from evaporation unit are by pump SP ₂11 send into three grades of pre-cooler VK in bath 12 ₁-VK ₃1 carries out the precooling cooling, when bath temperature is reduced to below 32 ℃, enters level Four crystallizer K ₁-K ₄In 2;

B, level Four crystallizer K ₁-K ₄2 each chamber gas phase are not gone here and there, and vacuum tightness differs, and the low temperature body lotion flows from left to right, crossing under the baffling stirring action of weir, spin upside down Homogeneouslly-radiating, and temperature is reduced to below 18 ℃, at the last step K of level Four crystallizer 2 ₄Middle crystallization goes out sodium sulfate;

C, at level Four crystallizer 2 last step K ₄The salt slurry of middle advantages of good crystallization is by brine pump SP ₁7 are transported to eddy flow enrichment device E10, and grain growth behind enrichment falls into water extracter Z9 then and carries out liquid-solid separation, and the mother liquor overflow of enrichment device E10 enters degassing vessel EG ₁16, and under vacuum action, suck three grades of body lotion condenser BK ₁-BK ₃In 3;

D, fall into saltcake storehouse 13 by the isolated sodium sulfate crystal grain of water extracter Z9 and be used to make Sodium sulfate anhydrous.min(99), and the desalination mother liquor enters another degassing vessel EG ₂8, under vacuum action, enter among the last step K4 of level Four crystallizer 2, carry out Crystallization Separation once more;

E, three grades of pre-cooler VK ₁-VK ₃The steam that 1 vacuum-evaporation goes out enters three grades of body lotion condenser BK respectively ₁-BK ₃In 3, the low temperature mother liquor that is overflowed by enrichment device E10 carries out condensation, and the low temperature mother liquor obtains direct heating simultaneously, when its temperature rises to 37 ℃, gets back to spinning tank 14 internal recycle and uses;

F, three grades of body lotion condenser BK ₁-BK ₃Residual gas in 3, and level Four crystallizer K ₁-K ₄Vaporised gas in 2 is inhaled into and is condensed into water among the off-gas condenser LQ4 and enters in the pond 15 of falling into water, uncooled residual gas enters the pond 15 of falling into water by steam jet pump D6 and water jet pump SPB5, and another effect that off-gas condenser LQ4, steam jet pump D6 and water pump are penetrated pump SPB5 is to keep pre-cooler VK ₁-WK ₃1, body lotion condenser BK ₁-BK ₃3 and crystallizer K ₁-K ₄2 vacuum tightness, the particularly effect of off-gas condenser LQ4.

Claims

1, a kind of continuous stirring vacuum sodium sulfate crystallization technology is characterized in that technical process is as follows:

A, will concentrate spinning bath and send into by pump (11) in the bath (12) and carry out pre-cooledly the pre-cooler (1), bath temperature is reduced to below 32 ℃, enter then in the multi-stage mold (2);

B, low temperature body lotion flow through multi-stage mold (2) successively, crossing under the baffling stirring action of weir, spin upside down mobile Homogeneouslly-radiating, and temperature is reduced to below 18 ℃, go out sodium sulfate in the last step crystallization of multi-stage mold (2);

C, the salt slurry that in multi-stage mold (2) last step, crystallizes into, be delivered to enrichment device (10) by pump (7), fall into water extracter (9) and carry out liquid-solid separation behind enrichment, degassing vessel (16) is gone in the mother liquor overflow of enrichment device, and sucks in the body lotion condenser (3) under vacuum action;

D, fall into saltcake storehouse (13), and the desalination mother liquor enters another degassing vessel (8), enters the last step of multi-stage mold (2) under vacuum action, carries out Crystallization Separation once more by the isolated sodium sulfate crystal grain of water extracter (9);

The steam that e, pre-cooler (1) vacuum-evaporation go out enters in the body lotion condenser (3), and the low temperature mother liquor that is overflowed by the enrichment device carries out condensation, and the low temperature mother liquor obtains direct heating simultaneously, when its temperature rises to 37 ℃, gets back to spinning tank (14) internal recycle and uses;

Residual gas in f, the body lotion condenser (3) and the vaporised gas in the multi-stage mold (2) enter and are condensed into water in the off-gas condenser (4) and enter in the drowning pond (15), uncooled residual gas enters drowning pond (15) by steam jet pump (6) and water jet pump (5), and the vacuum tightness of pre-cooler (1), body lotion condenser (3) and multi-stage mold (2) is also kept by off-gas condenser (4), steam jet pump (6) and water jet pump (5) simultaneously.

2, continuous stirring vacuum sodium sulfate crystallization technology according to claim 1 is characterized in that multi-stage mold (2) is the level Four crystallizer.

3, continuous stirring vacuum sodium sulfate crystallization technology according to claim 1 is characterized in that pre-cooler (1) is three grades of pre-coolers.

4, continuous stirring vacuum sodium sulfate crystallization technology according to claim 1 is characterized in that body lotion condenser (3) is three grades of condensers.