【作者】 李依丽；

【导师】 高晋生； 吴幼青；

【作者基本信息】 华东理工大学 ， 化学工艺， 2003， 博士

【摘要】 煤气化联合循环发电(IGCC)技术是最有发展前途的新一代发电技术,并且是最具商业竞争力的CCT技术。高温煤气净化是实现其高效和低污染的关键环节之一,脱除氯化氢和碱金属蒸气是高温煤气净化的重要内容,同时也是21世纪火力发电新技术中的重要课题。本文在固定床反应器中,对氯化氢的脱除进行了全面的研究,结果表明:以一种价亷易得的天然矿物,碱金属和碱土金属化合物为活性组分,通过大量的筛选实验及与两种工业脱氯剂对比研究,开发研制出性能优良的脱氯剂GH1,为高温含氯气体精脱氯提供了一种高效脱氯剂,其净化度小于1 mg/m3,穿透氯容量和饱和氯容量分别为37.2%和45.6%,机械强度为84 N/cm,超过了化工部的行业标准(50 N/cm);同时考察了各工艺条件对GH1脱氯性能的影响;等温反应动力学求得GH1与高温煤气中的氯化氢反应的反应级数为1,表观活化能为10.9 kJ/mol;基于固定床反应器恒定模式行为,研究了脱氯剂高温脱氯过程反应动力学,研究表明: GH1与高温煤气中的氯化氢气体的反应主要受化学反应控制,同时产物层的扩散控制是不容忽视的;对脱氯床层氯分布测定发现:随床层深度的增加,床层中脱氯剂的氯容量迅速下降,在床层的最上部,脱氯剂的氯容量高达45%,几近饱和,而床层的下部却不足1%。本文在自行研制的二段控温高温立式反应炉上进行碱金属蒸气脱除实验,结果表明:六种天然矿物及自制吸附剂对碱金属蒸气都具有吸附脱除性能,各吸附剂在有水蒸汽条件下的碱容量均高于无水蒸汽条件下的碱容量,其中自制样GM6、高岭土和活性氧化铝对碱金属蒸气具有较强的吸附作用,同时考察了反应温度和气体流量对三者碱容量的影响;基于固定床反应器恒定模式行为,研究了高岭土、活性氧化铝和GM6高温脱碱金属蒸气过程反应动力学,结果表明高岭土和活性氧化铝对碱金属蒸气的吸附同时受化学反应和产物层的扩散所控制;GM6在无水蒸汽的情况下对碱金属蒸气的吸附主要受固体产物层的内扩散阻力所控制,在有水蒸汽的情况下则同时受化学反应和产物层的扩散所控制;XRD和SEM结果表明无水蒸汽条件下活性氧化铝对碱金属蒸气的吸附是多分子层的物理吸附,吸附的主要阻力集中在碱金属蒸气扩散至吸附剂的内孔;XRD结果同样证明GM6在无水蒸汽条件下对碱金属蒸气的吸附是物理吸附,GM6在有水蒸汽条件下进行的主要是化学吸附;实验采用固定床反应器,利用管道煤气为载气,对活性氧化铝、高岭土和GM6的脱碱性能进行研究,原子吸收光谱法和电位滴定法证明此时活性Al2O3、高岭土和GM6对碱金属蒸气的吸附均属物理吸附。更多还原

【Abstract】 The integrated coal gasification combined cycle (IGCC) is a new power-generation scheme and a promising technology of coal cleaning technology (CCT). High temperature coal gas cleaning is one of key links to realize its higher efficiency and less pollution. The HCl-removal and the removal of alkali metal vapor from high temperature coal gas are not only a significant part of high temperature coal gas cleaning but also an important subject of new fired-power generation technologies into the 21-st century.In this paper, a new type of HCl-removal sobent GH1 for high temperature cleaning of coal gas was self-made in the lab. The sorbent made of a natural mineral, Ca(OH)2, Na2CO3 and NaHCO3 has high breakthrough chlorine content of 37.2% (in the condition of 650℃、2500 h-1 space velocity and 1800 ppm HCl input concentration) and high mechanical strength. It can be applied to practical industry. In addition, the effects of process factors were investigated. The experimental data obtained from HCl-removal were analyzed by a model based on fixed-bed reactor and shrinking core models. It was found that reaction between sorbent and HCl vapor is of first-order with respect to initial HCl concentration and the apparent activation energy is 10.9 kJ/mol. The adsorption process is governed mainly by chemical reaction, but the effect of the product layer diffusion cannot yet be neglected. Results of the distribution of chlorine in the sorbent bed indicated that sorbent in the upstream end of the bed is nearly saturated with the chlorine whereas sorbent in the downstream end only contains less than 1wt% chlorine.Six nature minerals and six self-made sorbents were used to remove alkali metal vapor in a self-made alkali metal vapor removing apparatus. Results found that kaolinite, activated alumina and self-made sorbent GM6 are very efficient for alkali metal vapor removal. The effects of temperature and gas volume of flow on sodium content were examined. Based on fixed-bed reactor model, adsorption process of alkali metal vapor on kaolinite and activated alumina under N2 without water vapor was found to be influenced by both adsorption reaction and diffusion of a sodium resultant layer from the kinetics. The adsorption of GM6 under N2 without water vapor is a physical adsorption controlled mainly by the product layer diffusion and under N2 with water vapor it is mainly a chemical adsorption controlled by both chemical control and the product layer diffusion. Results of XRD and SEM also indicated that the adsorption process of activated alumina under N2 is physical adsorption with multi-molecular layers. The adsorption process of GM6 is physical adsorption under N2 and is chemical fixation in the presence of water vapor based on the information of XRD. Results of atom absorbing spectrum and electric potential titration proved that the adsorption process of kaolinite, activated alumina and GM6 is physical adsorption under coal gas.更多还原