低温磷酸气液平衡组成及其典型条件下腐蚀行为研究
发布时间：2018-08-14 15:48
【摘要】：磷化工是国民经济不可或缺的产业之一。热法磷加工的主要产品黄磷是制造高纯磷酸和有机磷化学品的基础原料,然而,黄磷采用电炉法加热还原生产,能耗高。目前,由于材质腐蚀问题,占黄磷生产总能耗32%的黄磷尾气没有得到有效利用,制约了热法磷化工的发展。本课题针对黄磷尾气热能利用低温(≤300℃)段锅炉磷酸腐蚀问题,开展了 P2O5-H20体系气液平衡研究,获得了低温下平衡温度的气液相组成,依据所研究的平衡组成,确定了低温(≤300℃)段锅炉的几个典型平衡温度和对应磷酸产物浓度,选取七种材质进行了腐蚀性研究。得出的主要结论如下:通过设计p2O5-H2O体系气液平衡装置,获得常压下的低温(≤300℃)段不同平衡温度的气液相组成,绘制P2O5-H2O体系气液平衡温度与组成的关系图,典型温度100℃、150℃、200℃、300℃对应磷酸的平衡质量百分数分别为17.66%、61.66%、69.60%、75.37%(以 P205计)。利用热重分析技术对目标平衡温度的磷酸进行TG和DTG分析。以正磷酸浓度(H3P04)100%为界,将热解分为两种类型。第一个类型为低于100%H3PO4浓度,具有四个热解温度区,第一阶段对应的是正磷酸脱水;第二阶段对应的是聚磷酸再聚合脱水、少量含磷化合物脱出;第三阶段对应的是磷酸脱出大量分子迅速挥发;第四个阶段为残留物的挥发。第二个类型是高于100%H3P04浓度,因聚磷酸含游离水较少,低聚磷酸失重不明显,随着浓度升高,聚磷酸失重消失,故聚磷酸在第一个主热解阶段,DTG出峰不明显或不出峰,而第二个主热解阶段与低于100%H3P04浓度磷酸的热解区域相同。最后,研究碳素钢、09CrCuSb合金、工业钛、304、310S、316L、904L于不同平衡温度下磷酸环境的均匀腐蚀行为及特征。316L和904L在平衡温度为100℃、150℃、200℃、300℃下磷酸环境中均匀腐蚀性能显著优于碳素钢、09CrCuSb合金、工业钛、304、310S,而Ni含量较高的904L具有比316L更强的耐蚀性能。EDS分析表明在150℃和200℃磷酸环境中,904L生成的绿色钝化膜富含耐蚀元素Ni,该钝化膜的形成可抑制腐蚀的进一步发生。
[Abstract]:Phosphorus chemical industry is one of the indispensable industries in national economy. Yellow phosphorus, the main product of thermal phosphorus processing, is the basic raw material for producing high purity phosphoric acid and organophosphorus chemicals. However, the production of yellow phosphorus is heated and reduced by electric furnace, which results in high energy consumption. At present, due to the problem of material corrosion, the tail gas of yellow phosphorus, which accounts for 32% of the total energy consumption of yellow phosphorus production, has not been effectively utilized, which restricts the development of thermal phosphorus chemical industry. In order to solve the problem of phosphoric acid corrosion of yellow phosphorus tail gas by heat energy at low temperature (鈮，
本文编号：2183357
[Abstract]:Phosphorus chemical industry is one of the indispensable industries in national economy. Yellow phosphorus, the main product of thermal phosphorus processing, is the basic raw material for producing high purity phosphoric acid and organophosphorus chemicals. However, the production of yellow phosphorus is heated and reduced by electric furnace, which results in high energy consumption. At present, due to the problem of material corrosion, the tail gas of yellow phosphorus, which accounts for 32% of the total energy consumption of yellow phosphorus production, has not been effectively utilized, which restricts the development of thermal phosphorus chemical industry. In order to solve the problem of phosphoric acid corrosion of yellow phosphorus tail gas by heat energy at low temperature (鈮，
本文编号：2183357
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