PVC聚合工艺仿真培训系统操作手册
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聚氯乙烯生产工艺仿真培训系统
操 作 手 册
北京东方仿真软件技术有限公司
2009年7月
目 录
一、工艺流程说明 ································································································································································· 1
1.1生产方法 ······························································································································· 1
1.2工艺流程简介 ······················································································································· 1
二、工艺流程说明 ································································································································································· 4
2.1设备简介 ······························································································································· 4
2.2原料简介 ······························································································································· 6
三、仪表列表 ············································································································································································ 7
四、工艺卡片 ··········································································································································································10
五、复杂控制说明 ·······························································································································································10
六、重点设备的说明·························································································································································· 11
七、操作规程 ·········································································································································································· 11
八、仿真系统操作画面 ····················································································································································19 1 一、工艺流程说明
1.1生产方法
聚氯乙烯的聚合方法从乳液聚合、溶液聚合发展到悬浮聚合，本体聚合、微悬浮聚合等。国外目前以悬浮聚合（占80-85%）和二段本体聚合为主；国内目前以悬浮聚合为主，少量采取乳液聚合法。本仿真流程采用悬浮聚合法。
将各种原料与助剂加入到反应釜内在搅拌的作用下充分均匀分散，然后加入适量的引发剂开始反应，并不断地向反应釜的夹套和挡板通入冷却水，达到移出反应热的目的，当氯乙烯转化成聚氯乙烯地百分率达到一定时，出现一个适当的压降，即终止反应出料，反应完成后的浆料经汽提脱析出内含VC后送到干燥工序脱水干燥。
氯乙烯悬浮聚合反应，属于自由基链锁加聚反应，反应式如下：
n CH2=CHCl → —[—CH2 —CH—]n—
∣
Cl
它的反应一般由链引发剂，链增长，链终止，链转移几种元素反应组成。
1.2工艺流程简介
聚氯乙烯生产过程由聚合、汽提、脱水干燥、VCM回收系统等部分组成。同时还包括主料、辅料供给系统，真空系统等。其生产流程见图1.1及1.2。 2
图1.1 PVC生产流程示意框图
图1.2 PVC生产流程总图
3 1.2.1进料、聚合
首先向反应器内注入脱盐水，启动反应器搅拌，等待各种助剂的进料，水在氯乙烯悬浮聚合中使搅拌和聚合后的产品输送变得更加容易，也是一种分散剂影响着PVC颗粒形态。然后加入的是引发剂，氯乙烯聚合是自由基反应，而对烃类来说只有温度在400—500℃以上才能分裂为自由基，这样高的温度远远超过正常的聚合温度，不能得到高分子，因而不能采用热裂解的方法来提供自由基。而采用某些可在较适合的聚合温度下，能产生自由基的物质来提供自由基。如：偶氮类，过氧化物类。接下来加入分散剂，它的作用是稳定由搅拌形成的单体油滴，并阻止油滴相互聚集或合并。
对聚合釜加热到预定温度后加入VCM，VCM原料包括两部分，一是来自氯乙烯车间的新鲜VCM，二是聚合后回收的未反应的VCM，这些回收单体可与新鲜单体按一定比例再次加入到聚合釜中进行聚合反应。二者在搅拌条件下进行聚合反应，控制反应时间和反应温度，当聚合釜内的聚合反应进行到比较理想的转化率时，PVC的颗粒形态结构性能及疏松情况最好，希望此时进行泄料和回收而不使反应继续下去，就要加入终止剂使反应立即终止。当聚合反应特别剧烈而难以控制时，或是釜内出现异常情况，或者设备出现异常都可加入终止剂使反应减慢或是完全终止。
反应生成物称为浆料，转入下道工序，并放空聚合反应釜，用水清洗反应釜后在密闭条件下进行涂壁操作，涂壁剂溶液在蒸汽作用下被雾化，冷凝在聚合釜的釜壁和挡板上，形成一层疏油亲水的膜，从而减轻了单体在聚合过程中的粘釜现象，然后重新投料生产。
1.2.2气提
反应后的PVC浆料由聚合釜送至浆料槽，再由汽提塔加料泵送至汽提工序。蒸汽总管来的蒸汽对浆料中的VCM进行汽提。浆料供料进入到一个热交换器中，并在热交换器中被从汽提塔底部来的热浆料预热。这种浆料之间的热交换的方法可以节省汽提所需的蒸汽，并能通过冷却汽提塔浆料的方法，缩短产品的受热时间。VCM随气提汽从浆料中带出。气提汽冷凝后，排入气柜或去聚合工序回收压缩机，不合格时排空。冷凝水送至聚合工序废水汽提塔。
4 1.2.3干燥
气提后的浆料进入脱水干燥系统，以离心方式对物料进行甩干，由浆料管送入的浆料在强大的离心作用下，密度较大的固体物料沉入转鼓内壁，在螺旋输送器推动下，由转鼓的前端进入PVC储罐，母液则由堰板处排入沉降池。
1.2.4VCM回收
生产系统中，•含VCM的气体均送入气柜暂存贮，气柜的气体经泵送入水分离器，•分出液相和气相，•液相为水，内含有VCM再送到气提器。气相为VCM和氮气进入液化器，经加压冷凝使VCM液化，•液相VCM送VCM原料贮槽，不液化的气体外排。VCM回收系统工艺流程见图1.3。
••• 出料槽排气
汽提塔准备槽排气
气提汽
•••
•••
图1.3 VCM回收系统工艺流程图
二、工艺流程说明
2.1设备简介
表1 设备一览表
压
缩
机 水
分
离 液
化
气
水 VCM储槽 液 5 设备位号 设备名称
V510 新鲜VCM储罐
V506 回收VCM储罐
P510 新鲜VCM加料泵
P502 回收VCM加料泵
R201 聚合釜
P301 浆料输送泵
V301 出料槽
P302 出料槽浆料输送泵
V302 汽提塔进料槽
P303 气体塔加料泵
C301 浆料汽提塔
P305 汽提塔底泵
E301 浆料热交换器
E303 塔顶冷凝器
B501 间歇回收压缩机
B502 连续回收压缩机
V507 密封水分离器
V508 密封水分离器
V503 废水储罐
P501 废水进料泵
E501 废水热交换器
C501 废水汽提塔
E503 VCM回收冷凝器
E504 VCM二级冷凝器
V509 RVCM缓冲罐
T301 浆料混合槽
