锆添加剂对铁铈复合基高温煤气脱硫剂硫化性能的影响

发布时间：2018-03-10 04:05

本文选题：锆添加剂　切入点：铁铈脱硫剂　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：根据对能源结构和能源消耗的预测,煤炭将长期占据我国能源消费的主导地位。但随之而来的是现阶段煤炭的低效利用造成了严重的环境和能源问题。煤的洁净高效转化技术将成为解决这一问题的有效途径。整体煤气化联合循环(IGCC)和煤基多联产(CPG)等发电技术,以其高效率、低污染的环境友好特性,成为未来极具潜力的洁净煤技术可持续战略发展方向。然而,煤气化过程中产生的H2S会对管道设备、环境及人类健康等方面造成严重的危害。因此,高温煤气脱硫技术的研究具有重要的意义。本论文总结并分析了铁铈复合基高温煤气脱硫剂的优势及存在的问题,选择以第三组分锆作为添加剂,制备出具有脱硫活性好的铁铈锆复合高温煤气脱硫剂。在固定床微分反应器上考察了铁铈锆复合脱硫剂的脱硫行为,并结合XRD、N2吸附、XPS、H2-TPR、SEM-EDS等表征手段,探究锆添加剂对铁铈复合基脱硫剂结构、还原性能及硫化性能的影响,彼此关联,得到以下主要结论:(1)以共沉淀法制得的铁铈锆复合脱硫剂,其存在形式为Fe2O3-Ce1-xZrxO2。最佳制备条件为:Fe、Ce、Zr的摩尔比为1:0.8:0.2,焙烧温度为700oC。锆添加剂提高了氧化铁、氧化铈及铁铈复合脱硫剂的比表面积和孔容,有利于吸脱附硫;锆添加剂增加了氧化铈和铁铈复合脱硫剂的氧空位,促进了脱硫剂Ce4+→Ce3+的还原。(2)锆添加剂提高了铁铈复合脱硫剂中Ce4+的还原度,且降低了Ce4+体相还原温度,有利于脱硫剂中铁铈活性组分在相同温区进行还原反应。(3)与单一氧化铁和氧化铈脱硫剂相比,当硫化温度为600oC时,铁铈复合脱硫剂表现出更好的硫化性能,但其反应程度较低。在此温度下,铁铈复合脱硫剂中铈活性组分并未充分参与反应。(4)锆添加剂显著提高了铁铈复合基脱硫剂的脱硫精度、硫化反应活性组分利用率、穿透硫容、硫化反应程度并拓宽了其硫化反应温度范围。对于颗粒脱硫剂而言,还原及硫化反应均为由外而内的层式反应。在还原过程中锆添加剂促使Ce逐渐向外层富集或Fe逐渐向内层迁移,在硫化过程中Ce逐渐向内层迁移或Fe逐渐向外层富集,这种Fe、Ce元素的迁移规律有利于促使Ce参与到还原及硫化反应中。铁铈锆脱硫剂的硫化反应式为:Fe(7)(8)Zr2CesO(7)(8)(7)(8)3Hg2HsO(7)g(8)(7)(8)Ces2Fe SSO(7)(8)5HsSZr(7)gO(8)222xx)2(1222Xx132(10)(10)(28)(10)(10)(10)--(5)铁铈锆复合脱硫剂具有良好的硫化/再生循环稳定性。
[Abstract]:Based on projections of energy structure and energy consumption, Coal will occupy the leading position of energy consumption in our country for a long time. However, the low efficiency of coal utilization has caused serious environmental and energy problems at the present stage. The clean and efficient conversion technology of coal will become the solution to this problem. Effective ways. Integrated coal gasification combined cycle (IGCC) and coal-based multi-generation (CPG) and other power generation technologies, Due to its high efficiency and low pollution, environmental friendliness has become a potential sustainable strategic direction for clean coal technology in the future. However, H2S produced in coal gasification process will affect pipeline equipment. Therefore, the study of high temperature gas desulfurization technology is of great significance. This paper summarizes and analyzes the advantages and problems of iron and cerium based high temperature gas desulfurizer. Using the third component of zirconium as the additive, the desulphurizing agent of iron cerium zirconium composite high temperature gas with good desulfurization activity was prepared. The desulphurization behavior of the iron cerium zirconium composite desulfurizer was investigated in a fixed bed differential reactor. The influence of zirconium additive on the structure, reductive property and vulcanization property of iron-cerium composite desulfurizer was investigated by means of XRDD-N _ 2 adsorption and XRDN _ 2 / TPR-SEM-EDS. The main conclusions are as follows: (1) the iron-cerium zirconium composite desulfurizer was prepared by co-precipitation method. The optimum preparation conditions are as follows: the molar ratio of Fe _ 2O _ 3-Ce1-xZrxO _ 2 is 1: 0.8: 0.2, the calcination temperature is 700oC. The zirconium additive increases the specific surface area and pore volume of Fe _ 2O _ 3, ce _ 2O _ 3 and iron-cerium complex desulfurizer, which is beneficial to the adsorption and desorption of sulfur. The addition of zirconium increased the oxygen vacancy of cerium oxide and iron-cerium composite desulfurizer and promoted the desulfurization agent Ce4. 鈫扵he addition of zirconium to Ce3 increased the degree of reduction of Ce4 in iron-cerium complex desulfurizer and reduced the reduction temperature of Ce4 bulk phase. It is favorable to the reduction of iron-cerium active component in desulfurizer at the same temperature. (3) compared with the single iron oxide and cerium oxide desulfurizer, the iron-cerium composite desulfurizer exhibits better vulcanization performance when the curing temperature is 600oC. But the reaction degree is low. At this temperature, the active component of cerium in the iron-cerium compound desulfurization agent does not fully participate in the reaction. The zirconium additive significantly improves the desulphurization precision of the iron-cerium composite desulfurization agent, the utilization ratio of the active component of the sulfidation reaction, and the penetration sulfur capacity. The degree of vulcanization reaction and the temperature range of vulcanization reaction were widened. In the process of reduction, zirconium additive promoted the enrichment of ce towards the outer layer or the migration of Fe to the inner layer, and the ce gradually migrated to the inner layer or Fe to the outer layer during the vulcanization. The migration rule of Fe ~ (2 +) ce is beneficial to promote ce to participate in reduction and vulcanization. The sulfidation reaction formula of iron-cerium zirconium desulphurizer is Fe: Fe _ 7H _ 2H _ sO _ (7) H _ (2) H _ (se) O _ (7) O _ (8) H _ (2) H _ (2) H _ (se) O _ (7) C _ (8) C _ (2) H _ (2) Fe _ (2) O _ (7) SSOO _ (7O) _ (8) HsSZr _ (7) O _ (8222x) ~ (2) C _ (2) O _ (2) O _ (2) (Fe ~ (2 +)) Zirconium complex Desulfurizer has good stability of sulfidation / regeneration cycle.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ546.5

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