CN1317259C - Process for recovering dimethyl formyl amide from waste water - Google Patents
Process for recovering dimethyl formyl amide from waste water Download PDFInfo
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- CN1317259C CN1317259C CNB2005100867845A CN200510086784A CN1317259C CN 1317259 C CN1317259 C CN 1317259C CN B2005100867845 A CNB2005100867845 A CN B2005100867845A CN 200510086784 A CN200510086784 A CN 200510086784A CN 1317259 C CN1317259 C CN 1317259C
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Abstract
The present invention relates to a method for recovering dimethyl formamide from waste water, which belongs to the technical field of separation and purification of dimethyl formamide. The present invention discloses the method for recovering dimethyl formamide from waste water so as to solve the defects of large energy consumption and low economic benefit of treating and recovering dimethyl formamide (DMF) especially low concentration DMF in waste water by a traditional water method. The present invention is characterized in that the method mainly comprises two processes of extraction and rectification, firstly, organic solvent extraction is carried out to transfer the dimethyl formamide in water solution to the organic solvent, and then the dimethyl formamide is separated from the organic solvent by the rectification. Acidic impurities which are generated in the recovery technology are neutralized by organic alkali to eliminate the corrosion to devices caused by an article system. The energy consumption of the technology is greatly reduced, and the technology has the advantages of simple flow path and simple devices. The purity of obtained dimethyl formamide can reach 99.9%, and the recovery rate can reach 98.5%.
Description
Technical field
The present invention relates to the recovery method of solvent, particularly relate to extraction, the rectifying combination technique recovery method of the dimethyl formamide (DMF) in a kind of waste water, belong to the separating and purifying technology field of dimethyl formamide.
Background technology
N, dinethylformamide is called for short DMF, is a kind of good industrial solvent and organic synthesis material, is widely used in a lot of industries, wherein mainly contains: 1) polyacrylonitrile fibre spinning solvent; 2) in petrochemical complex as gas absorbent, the selectivity that is used for acetylene absorbs and the separation and purification of C4 such as divinyl; 3) in leatheroid production, be used as solvent.How the corresponding waste water that contains DMF in a large number that produced of these application processes reclaims DMF wherein cost-effectively and handles the waste water of following, and all is very important for raising enterprise whole economic efficiency, social benefit.
Specifically concerning the synthetic leather industry, DMF is a large amount of solvents that use of wet polyurethane (PU) leather factory, being mainly used in the batching dilution, wait to finish process of setting and soluble in water after utilize supporting device that DMF is reclaimed circulation again to reuse.At present, general directly by rectificating method the DMF-water sepn is come abbreviates water law as in the industrial practice.The shortcoming of water law is a technological process energy consumption height, and heat energy consumption accounts for more than 80% of DMF cost recovery, especially is not suitable for to contain the lower rare liquid waste disposal of DMF concentration.Domestic wet method is moved the interior DMF of waste liquid that discharges in the hymeniderm leather production process, and often concentration is very low, as uses domestic simple DMF water law retrieving arrangement at present, because the energy consumption height, recycling expense costliness makes factory not have direct economic benefit.If the DMF waste liquid directly is discharged in the external environment, is not only loss economically, and causes serious environmental to pollute.
Over past ten years, China PU leather industry development is swift and violent, producing competition is growing more intense, energy-conservation and environmental protection has become a very important problem, and the sector concentrates on scarce coal area, south mostly, year, quota of expenditure coal number was huge, if unit consumption of energy is declined to a great extent, annual producible direct economic benefit will be very considerable.
Summary of the invention
The present invention handles the particularly shortcoming that energy consumption is big, economic benefit is low that had of lower concentration DMF of DMF in the waste water, the method for DMF in a kind of new recovery waste water of proposition of reclaiming at traditional water law.This method at first is extracted into the DMF in the waste water in the organic phase by solvent extraction, by rectificating method organic solvent is separated with DMF then, obtains pure DMF product.
The invention provides the recovery method of dimethyl formamide in a kind of waste water, it is characterized in that: this method comprises extraction and two operations of rectifying, at first adopt organic solvent extraction, dimethyl formamide in the aqueous solution is transferred in the organic solvent, wherein said organic solvent and dimethyl formamide are miscible, with boiling-point difference 〉=80 of dimethyl formamide ℃, and solubleness＜1% of described organic solvent in water; And then realize separating of dimethyl formamide and organic solvent by rectifying.
Furtherly, the rectifying separation operation of described organic solvent and dimethyl formamide is divided into two sections of initial gross separation and refining purifying, and wherein the rectifying mode that adopts of initial gross separation is an atmospheric distillation, and the rectifying mode that refining purifying adopts is rectification under vacuum.
In the present invention, the refining purification section of the rectifying separation operation of described organic solvent and dimethyl formamide adopts the mode extraction dimethyl formamide of side line gas phase discharging.
In purification column, add quadrol or diethylamine in described refining purification phase,, reduce the corrodibility of system with the acidic substance that produce in the N-process.
In the present invention, described extraction process equipment can adopt packed extraction tower.
The invention has the beneficial effects as follows:
1) whole Separation and Recovery process energy consumption reduces greatly.The present invention adopt the organic solvent extraction technology with DMF with become separating of DMF and organic solvent separating of water.Extraction process carries out at normal temperatures, and energy consumption is low, with treatment scale 1m
3/ hr is an example, need power consumption 0.75 degree/hour.Selected organic extractant separates with DMF than easier with water, and the vaporization heat of organic extractant is about 1/8 of water, with DMF boiling-point difference bigger (more than or equal to 80 ℃), the progression that sepn process needs is few, reflux ratio is low, and steam consumption significantly reduces, and energy consumption obviously reduces.With 1m
3The waste water of/hr (DMF 10%) treatment scale is an example, and the entire treatment device only needs 1 ton of 8 kilograms of boiler as power, and usage load is about original 60%;
2) inorganic salts in the waste water, solid substance are the problems that must consider in traditional water law treating processes, and these impurity are separated out in rectifying workshop section vaporizer easily, fouling, thereby cause the obstruction of vaporizer tubulation, are difficult to cleaning, have a strong impact on operation.Because novel method adopts the organic solvent extracting taking technique, the mineral-type impurity in the waste water comprises that solid substance all discharges with water, thereby has significantly reduced in the conventional processes that impurity enters in the rectification working process and the rectifying tower reboiler stopping state that produces.
3) because rectification working process divides two sections of initial gross separation and refining purifying, the rectifying mode that wherein refining purifying is adopted is rectification under vacuum, to reduce the service temperature of sepn process, make the whole recovery process temperature be no more than 130 ℃, significantly reduce the decomposition of DMF and system to the corrosive nature of separating device material, also improved heat utilization efficiency.
Utilize the purity of the DMF of the method for the invention recovery can reach 99.9%; the rate of recovery can reach 98.5%; economy with respect to water law is better; thereby can handle the DMF waste water of lower concentration; it is also lucrative that feasible processing is lower than the DMF waste liquid of 10% concentration; under the situation that the international energy price is more and more high and environment protection becomes more and more important at present, its application prospect is very wide.
Description of drawings
Fig. 1 is the FB(flow block) of an embodiment of the method for the invention.
Embodiment
The invention provides the recovery method of dimethyl formamide in a kind of waste water (DMF), this method mainly comprises extraction and two operations of rectifying, at first adopt organic solvent extraction, the DMF in the aqueous solution is transferred in the organic solvent, and then realize separating of DMF and organic solvent by rectifying.Extraction agent selects to satisfy the organic solvent of following character: with DMF good consistency (being generally miscible) is arranged 1.; 2. the consistency with water very low (solubleness in water＜1%): 3. with boiling-point difference 〉=80 of DMF ℃.The solvent of Chang Xuan such as chloroform, tetracol phenixin, 1,1 ethylene dichloride, 1,1,1 trichloroethane, 1,2 Ethylene Dichloride, chloropropane and tri chloropropene etc.The rectifying separation operation of described organic solvent and dimethyl formamide is divided into two sections of initial gross separation and refining purifying, and wherein the rectifying mode that adopts of initial gross separation is an atmospheric distillation, and the rectifying mode that refining purifying adopts is rectification under vacuum.The smart vacuum pressure value of slipping of decompression can be-0.04～-0.07MPa between, vacuum tightness is too little, does not have to reduce smart effect of slipping temperature in the tower, vacuum tightness too greatly then increases loss of extractant and vacuum energy consumption.
The present invention is implemented as follows: at first lower concentration DMF waste water (mass percent concentration≤10%) is fed extraction tower, waste water carries out the exchange of liquid-liquid extraction mass transfer with the organic solvent of respective streams ratio in extraction tower, DMF enters the organic extraction phase by water, and impurity such as solid substance is then stayed water (extracting phase) in the waste water.The organic extraction that contains DMF then enters the rectifying separation operation mutually.The rectifying separation operation is divided two sections, promptly realizes the upgrading tower of initial gross separation and the purification column that realizes making with extra care purifying.Upgrading tower is the atmospheric distillation tower, and extraction phase is condensed into the organic solution that contains about DMF50% therein.At last concentrated solution is fed the DMF purification column, purification column is the rectification under vacuum tower, reaches the reduction rectification temperature by decompression, reduces system component and decomposes and the corrosive purpose.Purity be 99.9% DMF by the extraction of side line gas phase, can obtain the finished product after the condensation.
The acidic impurities that produces in the recovery technological process of the present invention utilizes organic bases (as quadrol, diethylamine etc.) to react neutralization, organic bases from purification column bottom side line continuously by being metered into.The degree of DMF hydrolysis can judge indirectly and obtain by regularly the potential of hydrogen of system rectifying tower still being carried out titration, and the add-on of definite organic bases thus.
Because the method for the invention earlier is transferred to organic phase with DMF by water by the less energy-consumption extraction process, by rectifying organic extractant is separated with DMF then, therefore whole process is compared energy consumption with traditional water law and is reduced greatly.Especially for DMF concentration less than 10% waste water, the water more than 90% need be steamed during with traditional water law recovery, energy consumption is huge, from becoming unreasonable economically, and with the obvious advantage with the method for the invention, can obtain economy and environment economic benefits and social benefits benefit.
Below in conjunction with accompanying drawing a specific embodiment of the present invention is described.
As shown in Figure 1, the DMF aqueous solution of 10% (mass percent concentration) is entered gently inlet mutually of filler extraction tower bottom with 1.0 tons/hour flow, organic solvent (chloroform) enters heavy liquid inlet, extraction tower top with 2 tons/hour flow, and organic phase and water carry out the exchange of liquid-liquid extraction mass transfer in extraction tower.Contain DMF concentration and be 5% organic extraction and feed upgrading tower by the extraction tower heavy out.Waste water flows out from the cat head light phase export, discharging after extraction agent reclaims and further handles.Upgrading tower is an atmospheric distillation, and the still temperature is 95 ℃, and reflux ratio is 0.2.The organic solution of organic extraction simmer down to DMF concentration about 50% in upgrading tower is by discharging at the bottom of the tower.It is that extraction agent is back to extraction process that concentrated cat head distillates component.DMF concentration is to enter purification column after 50% organic solution is discharged from the upgrading tower bottom.Purification column is the rectification under vacuum tower, and vacuum is-0.05MPa that tower still temperature is 130 ℃.
Organic solution obtains separating by rectification under vacuum in this tower, and cat head returns the upgrading tower inlet for containing the organic extractant of a small amount of DMF (＜1%).Purity reach 99.9% DMF with the gas phase form from the side line extraction, after condensation, obtain the finished product.
Reclaim the acidic impurities that produces in the technological process and utilize the organic bases quadrol to react neutralization, organic bases from purification column bottom side line continuously by being metered into.The small molecules resin impurity that enters distillation system in a spot of solid substance in the system (most solid substances enter raffinate item aqueous phase in the waste water in extraction process, discharge with water), the waste water is regularly discharged from the purification column bottom by thermogenetic viscous fluid and acid-base neutralisation product etc.
Claims (5)
1. the recovery method of dimethyl formamide in the waste water, it is characterized in that: this method comprises extraction and two operations of rectifying, at first adopt organic solvent extraction, dimethyl formamide in the aqueous solution is transferred in the organic solvent, wherein said organic solvent and dimethyl formamide are miscible, with boiling-point difference 〉=80 of dimethyl formamide ℃, and solubleness＜1% of described organic solvent in water; And then realize separating of dimethyl formamide and organic solvent by rectifying.
2. the recovery method of dimethyl formamide in the waste water according to claim 1, it is characterized in that: the rectifying separation operation of described organic solvent and dimethyl formamide is divided into two sections of initial gross separation and refining purifying, wherein the rectifying mode of initial gross separation employing is an atmospheric distillation, and the rectifying mode that refining purifying adopts is rectification under vacuum.
3. the recovery method of dimethyl formamide in the waste water according to claim 1 is characterized in that: the refining purification section of the rectifying separation operation of described organic solvent and dimethyl formamide adopts the mode extraction dimethyl formamide of side line gas phase discharging.
4. the recovery method of dimethyl formamide in the waste water according to claim 1 is characterized in that: add quadrol or diethylamine in described refining purification phase in purification column, with the acidic substance that produce in the N-process, reduce the corrodibility of system.
5. the recovery method of dimethyl formamide in the waste water according to claim 1 is characterized in that: described extraction process equipment adopts packed extraction tower.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2005100867845A CN1317259C (en) | 2005-11-04 | 2005-11-04 | Process for recovering dimethyl formyl amide from waste water |
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| CNB2005100867845A CN1317259C (en) | 2005-11-04 | 2005-11-04 | Process for recovering dimethyl formyl amide from waste water |
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| CN1317259C true CN1317259C (en) | 2007-05-23 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10370398B2 (en) | 2016-06-23 | 2019-08-06 | Tate & Lyle Technology Limited | Liquid-liquid extraction of DMF |
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| CN101397260B (en) * | 2008-11-19 | 2012-06-27 | 河北工业大学 | Technology for recovering dimethylformamide from waste water by combination of saline extraction and rectification method |
| CN101792221B (en) * | 2010-04-09 | 2011-07-20 | 安徽南风环境工程技术有限公司 | Method for pre-treating N,N-dimethylformamide-containing waste water |
| CN102408349B (en) * | 2011-11-19 | 2014-07-02 | 无锡双象超纤材料股份有限公司 | System for removing formic acid generated during dimethylformamide recovering process |
| CN102557355A (en) * | 2012-02-15 | 2012-07-11 | 蒋梦琪 | Treatment method of wastewater containing amino compounds by copolymerization and extraction |
| CN104003566B (en) * | 2014-05-28 | 2015-08-05 | 东莞市灿森新材料有限公司 | The recovery method of many components waste liquid in high-performance aramid fiber fibrid production process |
| CN104384172B (en) * | 2014-10-25 | 2016-09-21 | 傅颖 | A kind of synthetic leather produces the method for disposal of rectification residue |
| CN104844433B (en) * | 2015-01-07 | 2016-09-21 | 青岛科技大学 | A kind of method of high-low pressure double-tower rectification acetone/DMF/ water ternary system |
| CN106397252B (en) * | 2016-08-31 | 2020-08-25 | 普洛药业股份有限公司 | Device and method for efficiently recycling DMF (dimethyl formamide) from wastewater |
| CN106565524A (en) * | 2016-09-22 | 2017-04-19 | 南通万顺化工科技有限公司 | A method of recovering dimethyl formamide |
| CN106748864B (en) * | 2016-12-27 | 2019-02-05 | 广东创源节能环保有限公司 | A kind of technique of the double heat pump distillation method processing DMF waste water of low pressure economic benefits and social benefits |
| CN107215994A (en) * | 2017-06-16 | 2017-09-29 | 山东康宝生化科技有限公司 | A kind of method for concentrating the dilute DMF waste water of Sucralose |
| CN108059291B (en) * | 2017-10-26 | 2020-09-04 | 山东鑫泉医药有限公司 | Method for recovering DMF (dimethyl formamide) and inorganic salt in ceftazidime side chain acid ester wastewater |
| CN108793553A (en) * | 2018-06-09 | 2018-11-13 | 石家庄市绿丰化工有限公司 | A kind of method of DMF Sewage treatments |
| CN108774148A (en) * | 2018-07-11 | 2018-11-09 | 刘志 | A kind of PU synthetic leather wet method prepare in the recovery and treatment method of solvent |
| CN108862795A (en) * | 2018-07-16 | 2018-11-23 | 兰博尔开封科技有限公司 | The synthetical recovery processing method of DMF in a kind of cyazofamid waste water |
| CN108947147A (en) * | 2018-08-30 | 2018-12-07 | 常州大学 | A kind of DMF advanced waste treatment apparatus |
| CN109179838A (en) * | 2018-10-11 | 2019-01-11 | 凯莱英生命科学技术(天津)有限公司 | The processing method of DMF waste water containing triethylamine |
| CN110064222B (en) * | 2019-05-08 | 2021-09-28 | 河北德瑞化工有限公司 | Extracting agent and method for treating thiamethoxam production wastewater by using same |
| CN111470997A (en) * | 2020-04-26 | 2020-07-31 | 安庆市鑫祥瑞环保科技有限公司 | Method for recovering DMF waste liquid |
| CN112479919A (en) * | 2020-11-30 | 2021-03-12 | 安徽金禾实业股份有限公司 | Method for recovering dilute DMF (dimethyl formamide) in sucralose crystallization mother liquor wastewater |
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- 2005-11-04 CN CNB2005100867845A patent/CN1317259C/en not_active Expired - Fee Related
Non-Patent Citations (1)
| Title |
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| 石油化工设计 仇汝臣 孔锐睿 石德武 方晨昭 孙道兴 胡仁梁，二甲基甲酰胺溶剂回收装置焦油塔减压改造方案 2003 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10370398B2 (en) | 2016-06-23 | 2019-08-06 | Tate & Lyle Technology Limited | Liquid-liquid extraction of DMF |
| US10899783B2 (en) | 2016-06-23 | 2021-01-26 | Tate & Lyle Technology Limited | Liquid-liquid extraction of DMF |
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| CN1793111A (en) | 2006-06-28 |
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