二甲基乙酰胺废液的回收研究

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东华大学 硕士学位论文 二甲基乙酰胺废液的回收研究 姓名:刘明晶 申请学位级别:硕士 专业:环境工程 指导教师:陈寅生
20031201
论文摘要
二甲基乙酰胺废液的回收研究
摘要
N,N一二甲基乙酰胺是一种重要的工业溶剂,它对于化合物有很 强的溶解能力,主要在橡胶、树脂和纤维生产中使用。同时,它也是 生产共混聚醚砜中空纤维膜的重要反应溶剂。每年有大量的DMAC在 生产、使用和处景过程中倾倒入水体。这些水体中的有毒物质将对水 质环境造成有害影响,并危害人民健康和公众利益。本学位论文主要 研究了用萃取法和精馏法回收二甲基乙酰胺的可行性和工艺条件。 1.液一液萃取法回收废液中的DMAC。
very large gap,the target of separation can be obtained by the means of
rectification.We adopt the way of area,which was suggested by
Herrington,to verify thermodynamics coherence.The results show that data fit to thermodynamics relation
of extractant are investigated,Through mensurating the phase of DMAC—
Chloroform-Water ternary systems,the theoretic stage and the effect of
extraction are Baidu Nhomakorabeatudied.The five experimental stages with counter—current and four experimental stages with downstream extraction are operated. It is showed that under the conditions normal temperature and chloroform
在实验室小试分离研究中,采用间歇精馏操作方式,系统的研究 了回流比、操作压力、全回流等工艺条件对分离过程的影响。实验表 明:釜液轻组分浓度随精馏的进行不断下降,DMAC浓度逐渐增大,过 程分离效果较好。在前阶段采用恒定馏出液组成,使回流比逐渐跃升 进行操作:后半阶段采用恒定回流比R一3操作。即节约能量又缩短时 问,能保证得到较纯的DMAC,回收后的DMAC可达到回用的目的。
通过测定几种低沸点萃取剂对DMAC萃取的分配比,选用三氯甲烷 (分配比为1.23)作为对DMAC的萃取剂。为了达到快速测定DMAC 含量的目的,采用紫外分光光度法,在198rim处测定二甲基乙酰胺吸 光度一浓度曲线,利用多项式拟合求得浓度与吸光度关系式:C。。=
10.509A一0.3。
我们研究了各种影响因素对萃取平衡的影响,并通过对DMAC一三 氯甲烷一水三元体系相图的测定,对萃取模拟实验的理论级数和萃取 效果进行了计算。通过五级逆流和四级顺流萃取模拟实验,结果表明: 在常温20一35℃,用三氯甲烷萃取DMAC,当溶剂与水相体积比为2: l时,经五级逆流萃取,可将废液中30%(w/w)的D1^Ac含量降至300mg/1 以下。废液的p}{值对萃取效果有明显的影响,当废液的pH值较大时, 即偏碱性对萃取有利。 2.,精馏法回收废液中的DMAC
the process of operati on,the content of DMAC in the bottom of the
rectification tower increase smoothly.In the first period we keep the content of rectification solution constant and increase the reflux ratio.In
into dimethylamine on account of long time distillation.We think the
extraction process is the better in these two processes because the rectification process consumes plentiful energy in long time distillation.
本文通过研究,建立了二甲基乙酰胺回收的萃取和精馏两种方法。 考虑到精馏法费时长,耗能高,且由于长时问的蒸馏,少量DMAC分解 成二甲胺,因此我们认为萃取一分馏法是更佳的选择。鉴于DMAC在纺 织生产工艺中反复使用,用量较大,所以本研究结果对于降低成本、 扩大再生产、环境保护和三废治理都具有重要意义。
.Ⅳ.
论文摘要
Since the extensive application of DMAC as solvent and reaction medium
has been increased in textile and paper making fields,the obtained results are very useful i n reducing production cost,reproduction expending and environment protection.
conditions of DMAC’S recovery is our research’S emphases through
extraction and rectification processes.
A liquid—liquid extraction process is studied for recovering DMAC
separation are good and can be reused in the manufacture.
In this dissel’tation,the recovery of DMAC is determined in two processes. In the rectification process,We find DMAC decompounded
sulfone hollow fiber membrane.However,a lot of DMAC waste liquid
inpour into water area during manufacture,use and disposal every year Losses of these toxic substances to the ambient water may lead to an adverse environment impact Oil the water quality and thus endanger public health and welfare.In this dissertation,the feasibility and
liquid equilibrium data of DM AC—Water system have been determined by
double circle vapor—liquid equilibrium kettle.Because there is no constant
boiling point and boiling temperature between DMAC and Water has a
首先使用阿贝折光仪测定DMAC一水二元系统折光率一组成数据,
由拟合得折光率一组成关系式:”D25 2 1.3286+0-1684XDMAC一0.0572XM2 c。
利用双循环气液平衡釜测定DMAC一水气液相平衡数据,可知该溶液无
论义摘要
恒沸现象,且两绸分沸点棚≥jj较大,采用精馏法可以达到分离的目的。 采用Herri ngt 0n等提出的面积法校验数据的热力学一致性,实测数据 符合热力学的普遍关联式。
extraction when the ratio of organic phase tO aqueous phase is 2:1.The value of pH has obvious influence on extraction efficiency;higher pH value is advantages to extraction.
being the extractant.the DMAC concentration in the aqueous effluent can
·Ill-
论文摘要
be decreased from 30%(w/w)to about 300mg/1 by 5-stage counter current
the second period we make reflux ratio equal to 3 and extracted middle rectification solution.In this way,not only economize energy and shorten the time of opel’ation,but also we can gain pure DMAC.So the effects of
wave length 1 98rim was establi shed.Correlation between the absorbency and composition of the binary solution is reported:CwAc=10.509A一0.3.
The effects of several variables such as temperature,pH and dosage
from waste liquid.In contrast with other low boiling point extractats,we choose chloroform as the extractant.For the purpose of quick analysis,
an ultraviolet absorption spectrophotometry for determining DMAC at
关键词:二甲綦乙酰胺、萃取、精馏、气液相平衡、回收、废液处理
堡苎塑茎——
Research On the Recovery of DMAC
i n the Waste Li qui d
ABST RACT
As an important industrial solvent,N,N—dimethylacetamide(DMAC)
has a strong ability of dissolution for many compounds,which frequently encountered in the manufacture of rubbers,resins and fibers.At the same time,it is an important reaction medium in the manufacture of polyether
The date of both the refractive index and composition were measured by refractivemeter Correlation between the refractive index and
c。mp。siti。n is rep。rted:"葶=1·3286+0·1684xMf一0.0572xM2 c.Vap。r
The DMAC and Water mixture was separated in a laboratory
rectification tower,and the effects of several variables such as reflux ratio,pressure and accumulative batch distillation is investigated.During
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