CN102329407B - Technology for recycling dilute formaldehyde generated in production of paraformaldehyde - Google Patents
Technology for recycling dilute formaldehyde generated in production of paraformaldehyde Download PDFInfo
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- CN102329407B CN102329407B CN201010223717.4A CN201010223717A CN102329407B CN 102329407 B CN102329407 B CN 102329407B CN 201010223717 A CN201010223717 A CN 201010223717A CN 102329407 B CN102329407 B CN 102329407B
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Abstract
The invention discloses a technology for recycling dilute formaldehyde generated in the production of paraformaldehyde. The technology comprises the following steps: 1, mixing an evaporated dilute formaldehyde solution in a raw material tank, conveying to a vapor-liquid separation pot with a raw material charging pump, heating with waste heat from a charging preheater of a formaldehyde removing tower, and allowing to enter a next scraping film evaporator with a pump through the flow control; 2, carrying out heating condensation on the formaldehyde solution with the scraping film evaporator, allowing the condensed formaldehyde solution to enter a collection pot, and conveying to the raw material tank in the pot with a pump through the liquid level control; 3, allowing water vapor entrained with formaldehyde to evaporate from the scraping film evaporator, condensing with a condenser, and allowing the dilute solution to enter the collection pot; and 4, pumping the dilute solution to enter the formaldehyde removing tower with a pump, accessing saturated vapor to a reboiler, pressurizing the formaldehyde solution, condensing a formaldehyde gas and water vapor with a tail condenser and to enter the collection pot. The technology which allows the separation of formaldehyde from water to be realized, and a dual purpose of the formaldehyde recycle and the separation of water in a system to be reached has the advantages of extremely high environment benefit and economic benefit.
Description
Technical field:
The present invention relates to a kind of circulation use technology of the rare formaldehyde produced while producing paraformaldehyde.
Background technology:
Paraformaldehyde production be take formaldehyde as main raw material, by evaporating, concentrate, through catalyzing and condensing, obtaining solid formaldehyde, then makes finished product through vacuum-drying.But having a large amount of rare formaldehyde in the process of producing paraformaldehyde produces, how to process rare formaldehyde, become the difficult problem of paraformaldehyde manufacturer, process rare formaldehyde in existing documents and materials, most published methods are only the angles from environmental protection, utilize chemical transformation formaldehyde to be converted into to the material of the discharge of environment permission, or by the method for biochemical treatment, these methods are processed rare formaldehyde and are had shortcomings: transform not exclusively, generation due to side reaction, the form that part formaldehyde further transforms with formaldehyde and formate exists, therefore the solution after conversion processing can not directly discharge, formaldehyde is converted to the formose class, can not recycling, cause the wasting of resources.
Summary of the invention:
The objective of the invention is in order to overcome above deficiency the circulation use technology of the rare formaldehyde produced when a kind of easy to operate, time saving and energy saving, safe and reliable production paraformaldehyde is provided.
Purpose of the present invention is achieved through the following technical solutions: a kind of circulation use technology of the rare formaldehyde produced while producing paraformaldehyde comprises the following steps:
A, the rare formalin be evaporated is mixed at raw material tank, be transported in vapor-liquid separation tank with the raw material fresh feed pump, after utilizing the waste-heat of dealdehyder tower feed preheater, by pump, by flow control, enter next scraper-type film steamer;
Heating concentrates through scraper-type film steamer for B, formalin, and the formalin after concentrate enters holding tank, with pump, by liquid level, is controlled, and is delivered to raw material tank in tank;
C, the water vapour of carrying formaldehyde secretly steam from the top of scraper-type film steamer, and through condenser condenses, diluent enters holding tank;
D, with pump, by flow control, thin liquid is squeezed in dealdehyder tower, in reboiler, passed into saturation steam, formalin is after pressurization, and formaldehyde gas and water vapour, by the condensation of tail cooler, enter holding tank.
The present invention compared with prior art has the following advantages:
It realizes separating of formaldehyde and water, and formaldehyde also continues recycle through concentrated for paraformaldehyde production, reaches the dual purpose of water in the recycle of formaldehyde and separation system, has high environmental benefit, economic benefit and real suitability for industrialized production meaning.
Embodiment:
In order to deepen the understanding of the present invention, below in conjunction with embodiment, the invention will be further described, and this embodiment only, for explaining the present invention, does not form limiting the scope of the present invention.
Produce paraformaldehyde technique: will be about from the concentration of formaldehyde production device 55% concentrated formaldehyde and be delivered in a falling-film evaporator by transferpump, in falling-film evaporator by pulling vacuum to 200bara, pass into the steam of 4barg in chuck, after being concentrated to more than 70% by raw material, again by pump delivery to a scraper-type vaporizer, in same scraper-type vaporizer by pulling vacuum to 300bara, pass into the steam of 4barg in chuck, by 70%, be concentrated to more than 80%, arrive the concentrated formaldehyde tundish by pump delivery, enter spray drying system, in spray drying system, concentrated formaldehyde passes through high-pressure pump after adding catalyzer, be transported to each road nozzle, through the nozzle spray granulation, paraformaldehyde after granulation is through fluidised bed drying, enter the packaging unit packing after cooling, can produce rare formaldehyde while producing paraformaldehyde.
A kind of embodiment of the circulation use technology of the rare formaldehyde produced when the present invention produces paraformaldehyde comprises the following steps:
A, the rare formalin be evaporated is mixed at raw material tank, with the raw material fresh feed pump, be transported in vapor-liquid separation tank, after utilizing the waste-heat of dealdehyder tower feed preheater, the waste-heat of dealdehyder tower feed preheater, to 60-70 ℃, enters next scraper-type film steamer by pump by flow control;
Heating concentrates through scraper-type film steamer for B, formalin, formalin after concentrate enters holding tank, with pump, by liquid level, is controlled, and is delivered to raw material tank in tank, the pressure-controlling of scraper-type film steamer is below 2bar/g, and the operating pressure of scraper-type film steamer is controlled at below 0.1bar;
C, the water vapour of carrying formaldehyde secretly steam from the top of scraper-type film steamer, and through condenser condenses, diluent enters holding tank;
D, with pump, by flow control, thin liquid is squeezed in dealdehyder tower, in reboiler, passed into saturation steam, Steam pressure control is below 4bar/g, and formalin is after pressurization, and formaldehyde gas and water vapour, by the condensation of tail cooler, enter holding tank.
The important physicochemical property according to formaldehyde: along with the rising of the temperature and pressure of Formaldehyde-water system, the hydration reaction of formaldehyde moves to the direction of dehydration, the increased content of formaldehyde in formalin, and temperature is higher, the speed of dehydration reaction is faster, high more a lot of in the boil-off rate of formaldehyde in aqueous solution than formaldehyde.The present invention breaks methyl alcohol-formaldehyde in formaldehyde waste water by the means of physics, Formaldehyde-water, and the chemical interaction between the chemicals between Formaldehyde-water-derivative and chemical equilibrium relation, and finally realize separating of formaldehyde and water, by concentrated tower process for purification, by rare formaldehyde concentrate, by dealdehyder tower, water is separated with formaldehyde, concentrated formaldehyde is for the paraformaldehyde production cycle, isolated water beetle aldehyde, below 5ppm, reaches the emission standard of national regulation.The present invention has and realizes separating of formaldehyde and water, formaldehyde supplies paraformaldehyde production and continues recycle through concentrated, reach the dual purpose of water in the recycle of formaldehyde and separation system, high environmental benefit is arranged, the advantage of economic benefit and real suitability for industrialized production meaning.
Claims (2)
1. the circulation use technology of the rare formaldehyde produced while producing paraformaldehyde is characterized in that: comprise the following steps:
A, the rare formalin be evaporated is mixed at raw material tank, be transported in vapor-liquid separation tank with the raw material fresh feed pump, after utilizing the waste-heat of dealdehyder tower feed preheater, by pump, by flow control, enter next scraper-type film steamer;
Heating concentrates through scraper-type film steamer for B, formalin, and the formalin after concentrate enters holding tank, with pump, by liquid level, is controlled, and is delivered to raw material tank in tank;
C, the water vapor of carrying formaldehyde secretly steam from the top of scraper-type film steamer, and through condenser condenses, the formaldehyde thin liquid enters holding tank;
D, with pump, by flow control, the formaldehyde thin liquid is squeezed in dealdehyder tower, in reboiler, passed into saturation steam, formalin is after pressurization, and formaldehyde gas and water vapor, by the condensation of tail cooler, enter holding tank.
2. the circulation use technology of the rare formaldehyde produced while producing paraformaldehyde according to claim 1 is characterized in that: in described steps A, the waste-heat of dealdehyder tower feed preheater is to 60-70 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010223717.4A CN102329407B (en) | 2010-07-12 | 2010-07-12 | Technology for recycling dilute formaldehyde generated in production of paraformaldehyde |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010223717.4A CN102329407B (en) | 2010-07-12 | 2010-07-12 | Technology for recycling dilute formaldehyde generated in production of paraformaldehyde |
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| CN102329407A CN102329407A (en) | 2012-01-25 |
| CN102329407B true CN102329407B (en) | 2014-01-01 |
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| CN201010223717.4A Active CN102329407B (en) | 2010-07-12 | 2010-07-12 | Technology for recycling dilute formaldehyde generated in production of paraformaldehyde |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110041183A (en) * | 2019-05-15 | 2019-07-23 | 宜都市多邦化工有限公司 | The recycling system and method for dilute formaldehyde in a kind of production of paraformaldehyde |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1473811A (en) * | 2003-08-05 | 2004-02-11 | 洪海玲 | Method for producing low alcohol, high concentration formaldehyde |
| CN101273073A (en) * | 2005-08-26 | 2008-09-24 | 巴斯夫欧洲公司 | Method for production of polyoxymethylene homo- or co-polymers |
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- 2010-07-12 CN CN201010223717.4A patent/CN102329407B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1473811A (en) * | 2003-08-05 | 2004-02-11 | 洪海玲 | Method for producing low alcohol, high concentration formaldehyde |
| CN101273073A (en) * | 2005-08-26 | 2008-09-24 | 巴斯夫欧洲公司 | Method for production of polyoxymethylene homo- or co-polymers |
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| CN102329407A (en) | 2012-01-25 |
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Address after: 226000, No. 16, Central Road, Nantong economic and Technological Development Zone, Jiangsu, Nantong Patentee after: Nantong Jiangtian Chemical Co., Ltd. Address before: 226000, No. 16, Central Road, Nantong economic and Technological Development Zone, Jiangsu, Nantong Patentee before: Nantong Jiangtian Chemicals Co., Ltd. |