CN104193931A - Paraformaldehyde preparation system - Google Patents
Paraformaldehyde preparation system Download PDFInfo
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- CN104193931A CN104193931A CN201410396582.XA CN201410396582A CN104193931A CN 104193931 A CN104193931 A CN 104193931A CN 201410396582 A CN201410396582 A CN 201410396582A CN 104193931 A CN104193931 A CN 104193931A
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- film evaporator
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- paraformaldehyde
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Abstract
The invention discloses a paraformaldehyde preparation system. The preparation system comprises steps of raw material preparation and processing, primary concentration through a falling film evaporator, secondary concentration through a thin film evaporator, spray granulation, and fluidized bed drying, wherein telomere is added for several times. According to the system disclosed by the invention, a polymerization phenomenon of formaldehyde in an evaporation and concentration system is effectively avoided; and the system can effectively reduce cost and improve production efficiency.
Description
Technical field
The present invention relates to technical field, particularly relate to a kind of preparation system of paraformaldehyde.
Background technology
Paraformaldehyde another name: poly-formaldehyde; Polymerization formaldehyde; Paraformaldehyde; Solid formaldehyde; Polymerization formaldehyde; English name: Paraformaldehyde; Polyoxymethylene; Molecular formula: HO-(CH2O) n-H, n=10-100; Low-molecular-weight is white crystalline powder, has formaldehyde taste; Fusing point is 120～170 DEG C; Be insoluble to ethanol, be slightly soluble in cold water, be dissolved in diluted acid, diluted alkaline.
Low polymerization degree paraformaldehyde replaces general industry formalin, at synthetic pesticide, synthetic resins, coating and produce in the diversified formaldehyde derived product such as fumigant, both can reduce the energy consumption of dehydration, can greatly reduce again wastewater treatment capacity, this is the environmental protection engineering of benefiting the nation and the people.Low polymerization degree paraformaldehyde, because it is high compared with industrial formol effective constituent, is solid particulate, is conducive to the application of the chemosynthesis such as chemical industry, pharmacy and other industrial circles, particularly requiring to use anhydrous formaldehyde to do aspect raw material synthetic, of many uses.Also can be used as sterilizing agent, sterilant, fumigant and weedicide and manufacture resin and artificial ivory etc.
In prior art, can not effectively avoid formaldehyde in evaporation concentration system, to produce polymerism, therefore a kind of simple to operate, the preparation system of paraformaldehyde reasonable in design is object of the present invention.
Summary of the invention
Object of the present invention is exactly the preparation system that a kind of paraformaldehyde is provided for the defect of above-mentioned existence.This system operation is simple, reasonable in design, can effectively avoid formaldehyde in evaporation concentration system, to produce polymerism, can effectively reduce costs, and enhances productivity.
The preparation system technical scheme of a kind of paraformaldehyde of the present invention is to comprise the following steps:
(1) raw material is prepared and is processed
Industrial formaldehyde solution is squeezed in the depolymerization still of paraformaldehyde device under keeping warm mode, controls the temperature of formaldehyde in depolymerization still at 100 DEG C, and under boiling state, refluxes 4 hours; In the time that temperature reaches 75 DEG C to charging in elementary falling-film evaporator;
(2) elementary falling-film evaporator is concentrated
Before charging, falling-film evaporator is carried out to preheating, then opens vacuum system, slowly to charging in falling-film evaporator, keep the temperature of formaldehyde in falling-film evaporator at 83-85 DEG C, add telogen, make formaldehyde solution by evaporation concentration to 70-75%; The formaldehyde solution concentrating enters middle one-level vapor seperator and separates;
(3) secondary thin-film evaporator is concentrated
Concentrated formaldehyde solution through elementary falling-film evaporator adds telogen under vacuum, through secondary thin-film evaporator evaporative concn to 85%;
(4) mist projection granulating
After finishing from the concentrated formaldehyde processing of upgrading unit, add again telogen reaction 1-3 hour, send into mist projection granulating tower and granulate.
(5) fluidised bed drying
Paraformaldehyde particle is further dry, cooling through vibrations fluidized-bed again, obtains paraformaldehyde finished product.
In step (2), add water vapor to be preheating to 30-40 DEG C to falling-film evaporator before charging, then open vacuum system, slowly, to charging in falling-film evaporator, adjust pressure at 80mmHg simultaneously, temperature out is at 55 DEG C.
One-level vapor seperator temperature 45-55 DEG C in step (2), pressure is at 80mmHg.
In step (2) telogen be trolamine with diethylamine by the mixture of any ratio, it is 0.5% that telogen accounts for methanol solution mass percent.
In step (3), in secondary thin-film evaporator, formaldehyde temperature is controlled at 90-95 DEG C.
Step is preheating to 55-65 DEG C to thin-film evaporator in (3) before charging, and opening vacuum pump maintenance pressure is 60 mmHg.
In step (3), telogen is propyl carbinol, accounts for 1% of concentrated formaldehyde quality.
In step (4), telogen is triethylamine, accounts for 1% of methanol solution quality.
In step (4), in mist projection granulating tower, temperature is 40 DEG C, and pressure is 320Pa.
In step (5), cooling temperature is 60 DEG C.
Beneficial effect of the present invention is: the preparation system of a kind of paraformaldehyde of the present invention adds telogen several times, simple to operate, reasonable in design, avoids occurring formaldehyde and in evaporation concentration system, produces polymerism, effectively enhances productivity.The paraformaldehyde product polymerization degree that obtains is low, stability in storage good, extended the shelf time of product, the constant product quality of acquisition.
embodiment:
In order to understand better the present invention, describe technical scheme of the present invention in detail with specific examples below.
(1) raw material is prepared and is processed
Industrial formaldehyde solution from formaldehyde plant is squeezed in the depolymerization still of paraformaldehyde device by formaldehyde transferpump under keeping warm mode.Control the temperature of formaldehyde in depolymerization still in 100 degree left and right, and under boiling state, reflux 4 hours.In the time that reaching 75 DEG C, temperature prepares to charging in the falling-film evaporator of elementary concentrating unit.
(2) elementary falling-film evaporator is concentrated
Before charging, suitably add water vapor to be preheating to 30-40 DEG C to falling-film evaporator, then open vacuum system, slowly to charging in falling-film evaporator, keep the temperature of formaldehyde in falling-film evaporator at 83-85 DEG C, add telogen, adjust quantity of steam and vacuum tightness simultaneously, pressure is at 80mmHg, temperature out, 55 DEG C of left and right, makes formaldehyde solution by evaporation concentration to 70 ~ 75%.
Wherein, telogen be trolamine with diethylamine by the mixture of any ratio, it is 0.5% that telogen accounts for methanol solution mass percent.
The pipeline of falling-film evaporator bottom, separator and conveying formaldehyde all has companion's heat with hot water, and the temperature that keeps formaldehyde in it more than 75 DEG C to prevent the polymerization of formaldehyde.
The formaldehyde solution concentrating enters one-level vapor seperator and separates, temperature 45-55 DEG C, and pressure is at 80mmHg, and a part of parting liquid loops back the top of falling-film evaporator through pump, use together with initial charge formaldehyde as raw material; Another part parting liquid evaporates formaldehyde transferpump to thin-film evaporator feed by one-level.The isolated formaldehyde gas of one-level vapor seperator and water vapour are sucked one-level vaporizer-condenser by vacuum, condensed rare formaldehyde solution enters one-level and evaporates rare formaldehyde tundish, enter one-level evaporation through rare formaldehyde recycle pump part and separate scum dredger, another part is sent into rare formaldehyde collection groove; The portion gas not being condensed is after one-level evaporation separates the further spray washing of scum dredger quilt, and rare formaldehyde solution enters the rare formaldehyde tundish of dual evaporation; The a small amount of formaldehyde that enters vacuum system carries out spray-absorption through follow-up waste gas absorption tower, can reach the requirement of environmental protection.
(3) secondary thin-film evaporator is concentrated
The formaldehyde solution that is concentrated to 70-75% left and right through elementary falling-film evaporator adds telogen under vacuum, and telogen is propyl carbinol, accounts for 1% of concentrated formaldehyde quality.Be increased to 85% left and right through thin-film evaporator evaporative concn, then with being pumped to granulating and drying unit.
Equally, before charging, thin-film evaporator is preheating to 55-65 DEG C, opening vacuum pump maintenance pressure is 60 mmHg.Content evaporates formaldehyde transferpump in the formaldehyde solution of 70-75% left and right by one-level sends into thin-film evaporator.The concentrated formaldehyde that concentration after concentrated reaches 85% left and right enters concentrated formaldehyde tundish, then sends into the concentrated formaldehyde tank of spraying granulation system through concentrated formaldehyde transferpump, and the formaldehyde that can not carry to granulating system is put into receiving tank.
The pipeline of concentrated formaldehyde medial launder and conveying concentrated formaldehyde all adopts hotwater tracing, and the temperature of hot water is controlled at 90 ~ 95 DEG C.
The gas mixture that contains formaldehyde gas and water vapour of extracting out from thin-film evaporator top enters dual evaporation condenser, in dual evaporation condenser gas, the content of formaldehyde is higher, in order not make the oxymethylene polymerization blocking pipe of condensation, the temperature that need to control condensation can not be too low.
The formaldehyde solution that dual evaporation condenser condenses is got off enters the rare formaldehyde tundish of secondary, then delivers to rare formaldehyde collection groove through the rare formaldehyde transferpump of dual evaporation.Enter dual evaporation through condensed remaining formaldehyde gas and separate scum dredger, after the further spray washing of rare aldehyde of being sent here by the rare formaldehyde recycle pump of one-level, enter holding tank here.The a small amount of formaldehyde gas that enters vacuum system carries out spray-absorption through follow-up waste gas absorption tower, can reach the requirement of environmental protection.
(4) mist projection granulating
After finishing from the concentrated formaldehyde processing of upgrading unit, add the reaction of telogen triethylamine, triethylamine accounts for 1% of concentrated formaldehyde quality, then with being pumped into mist projection granulating tower.At this, vaporific formaldehyde liquid is cooled, and in concentrated formaldehyde, moisture content is separated out, and forms paraformaldehyde particle, and the moisture content steaming is taken away by circulating nitrogen gas.Paraformaldehyde particle is further dry, cooling through vibrations fluidized-bed again, obtains paraformaldehyde finished product.Make carrier with nitrogen, by air conveying, paraformaldehyde finished product is sent into finished product packing unit.
(5) fluidised bed drying unit
The formaldehyde solution (85%) of high density is thrown in mist projection granulating tower by pump, and temperature is 40 DEG C, and pressure is 320Pa.Paraformaldehyde particle is further dried, is cooled to 60 DEG C through vibrations fluidized-bed again, obtains paraformaldehyde finished product.
Claims (10)
1. a preparation system for paraformaldehyde, is characterized in that, comprises the following steps:
(1) raw material is prepared and is processed
Industrial formaldehyde solution is squeezed in the depolymerization still of paraformaldehyde device under keeping warm mode, controls the temperature of formaldehyde in depolymerization still at 100 DEG C, and under boiling state, refluxes 4 hours; In the time that temperature reaches 75 DEG C to charging in elementary falling-film evaporator;
(2) elementary falling-film evaporator is concentrated
Before charging, falling-film evaporator is carried out to preheating, then opens vacuum system, slowly to charging in falling-film evaporator, keep the temperature of formaldehyde in falling-film evaporator at 83-85 DEG C, add telogen, make formaldehyde solution by evaporation concentration to 70-75%; The formaldehyde solution concentrating enters middle one-level vapor seperator and separates;
(3) secondary thin-film evaporator is concentrated
Concentrated formaldehyde solution through elementary falling-film evaporator adds telogen under vacuum, through secondary thin-film evaporator evaporative concn to 85%;
(4) mist projection granulating
After finishing from the concentrated formaldehyde processing of upgrading unit, add again telogen reaction 1-3 hour, send into mist projection granulating tower and granulate;
(5) fluidised bed drying
Paraformaldehyde particle is further dry, cooling through vibrations fluidized-bed again, obtains paraformaldehyde finished product.
2. the preparation system of a kind of paraformaldehyde according to claim 1, it is characterized in that, in step (2), before charging, add water vapor to be preheating to 30-40 DEG C to falling-film evaporator, then open vacuum system, slowly to charging in falling-film evaporator, adjust pressure at 80mmHg, temperature out is at 55 DEG C simultaneously.
3. the preparation system of a kind of paraformaldehyde according to claim 1, is characterized in that, one-level vapor seperator temperature 45-55 DEG C in step (2), and pressure is at 80mmHg.
4. the preparation system of a kind of paraformaldehyde according to claim 1, is characterized in that, in step (2) telogen be trolamine with diethylamine by the mixture of any ratio, it is 0.5% that telogen accounts for methanol solution mass percent.
5. the preparation system of a kind of paraformaldehyde according to claim 1, is characterized in that, in step (3), in secondary thin-film evaporator, formaldehyde temperature is controlled at 90-95 DEG C.
6. the preparation system of a kind of paraformaldehyde according to claim 1, is characterized in that, step is preheating to 55-65 DEG C to thin-film evaporator in (3) before charging, and opening vacuum pump maintenance pressure is 60 mmHg.
7. the preparation system of a kind of paraformaldehyde according to claim 1, is characterized in that, in step (3), telogen is propyl carbinol, accounts for 1% of concentrated formaldehyde quality.
8. the preparation system of a kind of paraformaldehyde according to claim 1, is characterized in that, in step (4), telogen is triethylamine, accounts for 1% of methanol solution quality.
9. the preparation system of a kind of paraformaldehyde according to claim 1, is characterized in that, in step (4), in mist projection granulating tower, temperature is 40 DEG C, and pressure is 320Pa.
10. the preparation system of a kind of paraformaldehyde according to claim 1, is characterized in that, in step (5), cooling temperature is 60 DEG C.
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| CN201410396582.XA CN104193931B (en) | 2014-08-13 | 2014-08-13 | A kind of preparation system of paraformaldehyde |
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| CN201410396582.XA CN104193931B (en) | 2014-08-13 | 2014-08-13 | A kind of preparation system of paraformaldehyde |
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| CN104193931B CN104193931B (en) | 2016-04-13 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106631735A (en) * | 2016-12-03 | 2017-05-10 | 宜都市多邦化工有限公司 | Polyformaldehyde redepolymerization system and method, and application thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102443121A (en) * | 2011-10-31 | 2012-05-09 | 江苏恒茂机械制造有限公司 | Production technology of paraformaldehyde |
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102443121A (en) * | 2011-10-31 | 2012-05-09 | 江苏恒茂机械制造有限公司 | Production technology of paraformaldehyde |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106631735A (en) * | 2016-12-03 | 2017-05-10 | 宜都市多邦化工有限公司 | Polyformaldehyde redepolymerization system and method, and application thereof |
| CN106631735B (en) * | 2016-12-03 | 2023-10-20 | 湖北泰盛化工有限公司 | System for depolymerizing paraformaldehyde and method and application thereof |
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| CN104193931B (en) | 2016-04-13 |
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