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目录

一、 前言······················································2 二、实验部分················································3

1、离子膜工艺优点················································3 2、离子膜生产工艺··············································4 (1)生产任务····················································4 (2)物料特性····················································4 (3)产品用途····················································4 (4)原料·························································5 (5)生产原理·····················································5 (6)工艺控制指标·················································9 (7)不正常现象及处理方法········································10 (8)安全生产····················································10 3、工艺优化········································11 三、结果分析························································13

1、成品质量检测方法·············································13 四、结论······················································14 参考文献··········································16 致谢·················································17

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离子膜烧碱生产和产品检测

[摘要] 介绍了国内烧碱行业的发展情况,指出离子膜烧碱的优点,并详细介绍了离子膜烧碱的生产工艺,在实际操作中进行了工艺的优化,如解决冷凝液倒流、排除不凝气。同时用酸碱滴定对产品进行了含量分析。 [关键字] 离子膜烧碱 分析 工艺

Ionic membrane caustic soda production and product

testing

0803 Industrial analysis and detection

[Abstract] Introduced the domestic caustic soda, and points out that the development of industry of ionic membrane caustic soda, introduces the advantages of ionic membrane caustic soda production technology, and in the actual operations of the optimization of the process, such as solving the condensate gas back, exclude coagulation. Use acid-base titration product was content analysis. [Key word] Ion film caustic soda, Analysis, Industrial art

一、前言

烧碱是一种重要的氯碱产品,在国民经济中占有重要地位,其中离子膜烧碱不仅质量好,能耗低,“三废”排放少,而且从根本上解决了由石棉隔膜法制碱造成的石棉绒对水质的污染和对操作人员健康的影响。

近年来,我国烧碱产业发展迅速,2004年生产能力只有1190万吨,2007年增加到2l81万吨,2008年进一步增加到2472万吨,同比增长l3.34%。其中离子膜法烧碱工艺因为具有能耗低、产品质量好,占地面积小,自动化程度高,清洁环保等优势发展较为迅速,新扩产的烧碱项目中以离子膜碱为主,2007-2008年扩能统计显示,新建离子膜烧碱产能占到同期烧碱扩能的92%[2]。

目前世界上生产烧碱的方法有4种:隔膜法、水银法、离子膜法、苛化法。隔膜法、水银法和离子膜法都是通过电解盐水生产烧碱;而苛化法则是以石灰和纯碱为原料制取烧碱。苛化法目前仅在少数地区采用,我国苛化法烧碱仅占总产

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量的1.7%左右。水银法烧碱含盐量低,产品浓度高,质量好,但是该法对环境污染严重,其汞害对人体有很大危害,联合国环境保护组织已要求逐步取代该法。隔膜法在国内外均广泛采用,该法早期为石墨阳极电解槽,在组装电槽中会产生大量铅和沥青烟雾,在操作中会生成石棉绒碱性污水和石棉绒粉尘,同时该法能耗非常大,因此,从20世纪70年代国内外开始用金属阳极电槽取代石墨阳极电解槽。目前发达国家已完全淘汰石墨阳极电解槽。我国的石墨阳极装置每年尚有约20多万吨的产量,国家已将其列入淘汰类工业生产能力。与石墨法相比,金属阳极隔膜法在技术上有了很大的提高,但能耗依然较高,产品质量较差,同时仍存在一定的石棉绒污染问题[1]。

20世纪80年代,我国离子膜烧碱装置全部采用引进的技术;20世纪90年代,具有自主知识产权的国产化离子膜法电解槽已逐步推广,但采用引进技术的装置仍居多数,本文介绍的离子膜烧碱蒸发工艺就是从国外引进的技术装置。

二、实验部分 1、离子膜工艺优点

(1)流程简单,简化设备,易于操作

由于离子膜碱液仅含有极微量的盐,所以,在其整个蒸发浓缩过程中,即使是生产99%的固碱,无须除盐。这就是极大的简化了流程设备,即隔膜碱蒸发必须有的除盐的设备及工艺工程都被取消,而且,由于在蒸发过程中没有盐的析出,也就很难发生管道阻塞,系统打水问题,使操作轻易进行。

(2)浓度高,蒸发水量少,蒸汽消耗低

离子膜法碱液的浓度高,一般在30%~33%,比隔膜法碱液的10%~11%要高很大,因而大量的减少了浓缩所用的蒸汽。若以32%的碱液为例,假如产品浓度为50%,则每吨50%的成品碱需蒸出水量为1.1t,而隔膜碱则一般要蒸出6.5t的水量。由于蒸发水量减少,蒸汽消耗就大幅度下降。以双效流程为例,一般仅耗汽0.73 ~0.78,另外蒸汽的空间也相应的减少,使设备的投资也相应降低。

(3)污染程度低

离子膜法生产装置排出的废液、废气均能做到回收利用,达标排放,对环境几乎没有污染。而隔膜烧碱产品质量较差,存在一定的石棉绒污染问题。

(4)生产稳定,安全性高

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