环氧乙烷乙二醇装置操作手册

环氧乙烷/乙二醇装置操作手册执笔：徐可敏张国甫审核：陈忠华环氧乙烷/乙二醇装置操作手册第1页共1页目录概述··························································································································161单元························································································································162单元······················································································································33B：操作·······················································································································3763单元······················································································································4364单元······················································································································5165单元······················································································································7766单元······················································································································8167单元······················································································································8768单元·····················································································································10069单元·····················································································································11470单元·····················································································································12974单元·····················································································································13381单元·····················································································································14082单元·····················································································································14683单元·····················································································································150检查纪录·····················································································································155操作指南·····················································································································157催化剂装填··················································································································175维护························································································································181概述第1页共181页概述陶氏化学公司为镇海炼化公司EO/EG装置提供的工艺设计包将推动实施装置的详细设计，保证装置达到高物料效率、有吸引力的能效、较高的产品质量、极低的污水排放。在催化剂的整个生命周期过程中，装置反应器可生产506.3kTA环氧乙烷并全部消耗用于生产乙二醇。装置的纯环氧乙烷生产能力可达到100kTA。装置操作安全、可靠。本操作手册包括有关开车、正常操作、停车和紧急工况等的说明和程序，镇海炼化可据此编写环氧乙烷/乙二醇装置详细的操作程序。装置根据工艺操作的逻辑区分划分成不同的部分。本手册对每一部分都提供了有关工艺、设备和仪表的说明以及各部分的特定安全注意事项和操作程序。本手册还包括一些针对整个装置的程序和信息。装置一般安全注意事项乙二醇装置在一定的温度和压力极限范围内处理高温、反应、易燃或有毒化学物质方面与其他化学加工装置非常相似。编写和执行安全规定及程序可保证人身和设备安全。这种程序一般包括但不限于火灾和蒸汽预防、人身保护性设备规范、设备维护程序。除化工厂内已有的安全注意事项，乙二醇工艺还有一些特殊的注意事项，包括防止反应系统形成易燃氧气/燃料混合物、乙烯/氧气混合物自燃、浓环氧乙烷分解以及乙二醇蒸馏塔内乙二醇/碱混合物分解。这些安全注意事项在操作手册相关区域的操作部分进行了详细讨论。本工艺设计包中规定的很多设计特性都是为了减少其中危害发生的可能性。防止这些危害发生最有效的方法是知识渊博、训练有素的操作和技术人员。应当培训员工使他们了解可能导致这种危害情况发生的各种条件、懂得对这种条件应当采取的纠正措施。作为补充保护手段，紧急停车系统(ESS)的配备是为了在人工动作未纠正潜在的不安全条件时，自动将各个系统切换到一种安全状态。各种具体的ESS系统在本手册的相应章节进行了详细说明。对本装置技术和操作人员任何严格的要求都不为过。61单元第1页共181页61单元A：工艺说明1前言环氧乙烷/乙二醇装置的第61部分叫做环氧乙烷(EO)反应系统。从其名称可以看出，本部分的主要功能是乙烯和氧在环氧乙烷反应器中的催化剂作用下发生反应生产环氧乙烷。2工艺的化学特征乙烯直接氧化成环氧乙烷的反应属于催化放热非均相1反应。环氧乙烷催化剂是特殊的。目前仅知道银是从商业角度唯一能够催化乙烯氧化成环氧乙烷的物质。促进剂、催化剂载体及催化剂制备方法可以提高催化剂活性和选择性(化学效率)。各主要商业环氧乙烷生产厂商使用的催化剂主要差别都在上述方面。而所有催化剂中的通用成份是银。乙烯催化氧化生成环氧乙烷的主要化学反应如下：1)C2H4+0.5•O2----C2H4O-104.891MJ/kg摩尔C2H422)C2H4+3•O2----2CO2+2H2O-1322.705MJ/kg摩尔C2H43)C2H4O+2.5•O2----2CO2+2H2O-1217.819MJ/kg摩尔C2H4O4)C2H4O(EO)----C2H4O(ACH)-114.648MJ/kg摩尔C2H4O方程式1和2是操作指南中计算所需的全部方程式。常规分析程序无法确定二氧化碳到底在方程式2，还是在方程式3中产生。反应式4说明了环氧乙烷异构生成了乙醛。反应式4不用银催化剂促进，而是用“其他”材料催化，如氧化铁(Fe2O3)和活性氧化铝。在正常的“清洁”反应器条件下，生成的乙醛量比环氧乙烷低四个级数。在反应器失控或接近失控状态时出现的高温条件会加速乙醛(和甲醛)的形成。反应器出口醛浓度如果超过10ppm（体积），可能导致最终产品的质量问题。微量的其他组份，如1，4-二氧杂环己烷在反应循环中生成。常规手段无法检测这些组份，但是在回收和乙二醇系统中这些组份会浓缩到可检测水平(ppm)。整个行业内环氧乙烷生产厂商采用的基本操作准则定义有时可能有些混乱。以下基于化学工艺特性的基本操作准则定义应当能够部分澄清这种混乱局面：A).收缩因子(sf)为反应器出口体积流量与入口体积流量之比。收缩因子是各种操作准则中计算物料与能量平衡所必须的。但是仅在反应器入口测量了反应器流量，这样就需要采取其他方法计算收缩因子。计算收缩因子时可以假设仅发生氧气与乙烯的化学反应，且反应仅生成环氧乙烷、二氧化碳和水，而忽略可能被燃烧的微量乙烷。充分利用每生成一个体积单位(LB摩尔、SCF等)的环氧乙烷，就有一半的体积单位丢失(反应式1)，收缩因子(sf)的定义见下列方程式：sf200XC2H4O200YC2H4OXC2H4O=反应器入口摩尔%环氧乙烷。YC2H4O=反应器出口摩尔%环氧乙烷。第二种计算收缩因子的方法是通过计算反应器入口完全惰性的组份，如Ar或N2的摩尔浓度与出口1非均相即反应物为气态而催化剂为固态，与均相中所有反应物都是同一状态相反。2260℃时的反应热。61单元第2页共181页浓度之比：sf=XAr/YAr后一种方法从理论上更准确，这是因为任何反应(而不是泄漏)产生的体积收缩都已经计算在内。收缩因子的倒数，1/sf常常用sk表示。B).△反应物与产品等于乙烯和氧气的消耗量与环氧乙烷、二氧化碳和水生产量，单位为摩尔量或其他体积量。显而易见，乙烯的消耗量可以通过下式计算：C2H4FR(in)XC2H4FR(OUT)YC2H4100FR(in)=反应器入口流量，体积单位(CMS，即立方米/秒)。FR(out)=反应器出口流量，体积单位(CMS)。XC2H4=反应器入口乙烯浓度YC2H4=反应器出口乙烯浓度一般情况下，仅测量入口或出口流量，但是因为FR(out)=sf•FR(in)，所以：C2H4=[FR(in)(XC2H4-sf.YC2H4)]/100修正的体积摩尔百分比差，通过在上式两侧同时乘以100/FR(in)可以得出：%C2H4=(XC2H4-sf.YC2H4)其他组份的△量按相同方法计算。C).碳和氧气平衡(C2BAL、O2BAL)将△%C2H4和△%O