为提高煤直接液化催化剂性能和氧化反应器运行的稳定性,通过分析影响催化剂性能及氧化反应器运行稳定性的因素,研究催化剂制备过程中的氧化反应温度、反应环境pH、氧化风量、反应器内物料流速、物料浓度等操作条件和氧化反应器塔盘结构优化调整措施。对不同操作条件下制备的催化剂在实验室进行高压釜煤直接液化评价,结果表明:α-FeOOH和γ-FeOOH晶相催化剂的形态为棒状或板条状结构,其比表面积越高煤液化活性越高,γ-FeOOH晶相催化剂较Fe3O4晶相催化剂对煤热解为沥青烯的催化效果最佳。通过调整氧化反应温度、反应环境pH、氧化风量等操作条件,制备出不同的催化剂,通过电镜扫描对比发现在工业装置上控制较低的氧化反应温度、较低的氧化反应环境pH及较高的氧化风量的操作工况下制备的催化剂晶型较好,催化剂可形成α-FeOOH或γ-FeOOH晶相,具有高分散度特性,催化剂性能最佳。针对目前工业化装置制备煤直接液化催化剂存在氧化反应温度高、在线pH计频繁失效、氧化反应器塔盘频繁堵塞等问题,提出了降低氧化反应温度、优化反应环境pH监控的方法以及后续改进措施。同时,通过提高氧化反应器内物料流速和减少塔盘数量减缓反应器塔盘堵塞,延长氧化反应器运行时间、提高运行稳定性。

In order to improve the performance of direct coal liquefaction catalyst and the operation stability of oxidation reactor, the influ⁃encing factors of catalyst performance and operation stability of oxidation reactor were analyzed. The operating conditions such as oxidationreaction temperature, pH of reaction environment, oxidation air volume, material flow rate and material concentration in the reactor, aswell as the optimization and adjustment measures of oxidation reactor tray structure during the preparation of catalyst were studied. The cat⁃alysts prepared under different operating conditions were evaluated in the laboratory for direct liquefaction of autoclave coal. The resultsshow that the morphology of α-FeOOH and γ-FeOOH crystal catalysts is rod-like or slate-like structure, and the higher the specific sur⁃face area is, the higher the coal liquefaction activity is. γ-FeOOH crystal catalyst has the best catalytic effect on coal pyrolysis to asphalt⁃ene compared with Fe3O4 crystal catalyst. Different catalysts is prepared by adjusting the operating conditions such asthe oxidation reactiontemperature, reaction environment pH, oxidation air flow. Through comparison with electronmicroscope scanning, it is found that the cata⁃lyst prepared under operating conditions of lower reaction temperature, loweroxidation environment, pH and higher oxidation air volume onindustrial devices has better crystal morphology. The product of the catalyst can form α-FeOOH or γ-FeOOH crystal phase, which hashigh dispersion characteristics and the best performance of the catalyst. Through analyzing the problems of high oxidation reaction tempera⁃ture, frequent failure of online pH meter and frequent clogging of oxidation reactor tray in the preparation of direct coal liquefaction catalystin industrial installations, the methods of reducing oxidation reaction temperature, optimizing pH monitoring of reaction environment andsubsequent improvement measures were put forward. At the same time, by increasing the flow rate of materials and reducing the number oftrays in the oxidation reactor, the blocking of trays can be slowed down, and the operation time of the oxidation reactor can be prolongedand the operation stability can be improved.

0 引言

1 催化剂制备工艺

   1.1 工艺流程

   1.2 催化剂

2 催化剂制备条件调整

   2.1 氧化反应温度

   2.2 氧化反应pH

   2.3 氧化风量

   2.4 氧化反应器内部结构的优化

3 结果与讨论

   3.1 目标催化剂产品的性能

   3.2 氧化反应温度对催化剂晶型的影响

   3.3 氧化反应pH对催化剂晶型的影响

   3.4 氧化反应风量对催化剂晶型的影响

   3.5 氧化反应器内部结构对催化剂性能的影响

4 结论与展望