高温煤气净化研究

2019-02-21 05:56:40

The coal gas Ni HCl









中文题名高温煤气净化研究

 





副题名 氨、有机硫、氯化氢、焦油组分和碱金属化合物的脱除 





外文题名 Study on the high temperature coal gas cleaning-removal of NH3,organic sulfur,HCl,tar component and alkali metal compounds 





论文作者豆斌林   





导师高晋生  沙兴中教授   





学科专业化学工艺   





研究领域\研究方向洁净煤技术   





学位级别博士 





学位授予单位华东理工大学   





学位授予日期2001   





论文页码总数108页   





关键词煤气净化  洁净煤   





馆藏号BSLW

/2001

/TQ546

/7 





【中文摘要】

    煤气化联合循环发电(IGCC)和煤气化燃料电池(MCFC)是正在开发中的新一代洁净煤发电技术。高温煤气净化正是这些技术实现高效和低污染的关键环节之一。高温煤气中最主要的污染物虽是固体颗粒与无机硫化物,但还有一些含量较少的污染物,包括有机硫化合物;煤焦油之类的重质烃;煤气中的HCl及HF;煤中的氮转化生成的氨;煤气中的碱金属蒸气等。这些污染物虽然数量较少,但危害却相当严重。
   本文在固定床反应器中,首先对高温煤气中氨、有机硫化物、氯化氢、焦油组分和碱金属化合物等分别进行了单独脱除的研究,结果发现:氧化态Ni-3催化剂在温度550-750℃的范围内对NH〓的脱除率很高,可达93%~94%,并具有较好的耐硫性能和较长寿命;选择两种硫化态的工业有机硫转化催化剂GS-100和Ni-3催化剂,对CS〓和COS进行催化转化的研究表明:硫化态的GS-100对CS〓和COS的氢解转化率为20%~40%,硫化态的Ni-3催化剂对CS〓和COS的氢解转化率则为60%~85%;用干混法自制的CNl脱氯剂具有较好的脱氯性能,并研究了工艺条件对其脱氯性能的影响。基于固定床反应器恒定模式行为的脱氯过程反应动力学研究表明:CNl脱氯剂与HCl气体的反应同时受化学反应与产物层扩散所控制。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,脱氯剂在床层上部接近饱和,而在下部氯容量不足2wt%;选择了铁基催化剂、三种镍基催化剂、5A分子筛、CaO、矾土和石英砂等八种催化剂,对焦油组分进行了加氢催化裂解研究得出:Ni-3催化剂对1-甲基萘和苯具有较高的催化裂解活性,并进行了裂解动力学和催化剂脱炭的研究;以NaCl为碱金属模型化合物,选择七种吸附剂对碱金属蒸气进行了脱除研究,结果发现:二级矾土、高铝土、高岭土、酸性白土和活性Al〓O〓的吸附效率较高,分别为85.3%,92.5%,88.0%,92.7%及98.2%,特级矾土最低,仅为12.28%,吸附3h的吸附碱容量活性氧化铝最高为6.20mg/g。研究还得出:在840℃条件下活性Al〓O〓吸附剂对碱金属化合物的脱除主要以物理吸附的方式进行。
   对NH〓、焦油组分(1-甲基萘)、有机硫化物(CS〓)、HCl等四种污染物进行了同时脱除的研究得出:CNl脱氯剂对HCl的转化率和氧化态的Ni-3催化剂对焦油组分的转化率均很高,硫化态的Ni-3催化剂是有机硫氢解转化较好的催化剂。在300~550℃之间,相同条件下以上污染物同时脱除转化率分别达79%、100%、88%、100%。最后对碱金属蒸气和HCl进行同时脱除的研究,发现在这两种污染物同时存在时,HCl气体的脱除率为100%,高铝土脱除碱金属蒸气的效率达79.5%,活性Al〓O〓为74.5%,特级矾土也达36.2%。











【外文摘要】

 ABSTRACT
   Coal is a complex and heterogeneous substance containing several impurities, including sulfur, chlor, nitrogen and metal compounds. The integrated coal gasification combined cycle (IGCC) produces electricity with a higher efficiency by converting coal to coal gas that can drive two turbine systems. The coal gas can also be used for Molten Carbonate Fuel Cells (MCFC) . In this case, the coal gas must be treated to remove impurities such as particulate, H〓S, NH〓, organic sulfur, HCl, tar, alkali metal compounds and so on. The amounts of NH〓, organic sulfur, HCl, tar, alkali metal compounds, being present in coal-derived gas are generally small, compared to those of particulate and sulfur compounds, but their harmfulness to the above mentioned power generation systems is quite severe.
   In this paper, the experiments were first carried out to separately remove NH〓, organic sulfur, HCl, coal tar component and alkali metal compounds in high temperature coal gas. The test results show Ni-3 catalyst is an effective catalyst for NH〓 at 550~750℃, with a conversion of 93%~94%, and has a long operation life and better anti-sulfur behavior. Two commercial sulfurized catalysts, Ni-3 and GS-100, were chosen to convert organic sulfur in high temperature coal gas into H〓S. It is observed that the conversions of CS〓 and COS is respectively 20%~40% by GS-100 catalyst and 60%~85% by Ni-3 catalyst. The CNl sorbent self-made has the highest chlorine capacity. The experimental data obtained from chlorine removal were analyzed by a model based on fixed-bed reactor and shrinking core models. It is found that reaction between sorbent and HCl vapor is of first-order with respect to initial HCl concentration. This reaction is governed by combination of the chemical reaction and product layer diffusion. The distribution of chlorine in the sorbent bed was determined. It is found 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 2wt% of chlorine. The tar decomposition activities of eight catalysts including Fe based catalyst, three Ni based catalyst, 5A molecular sieve, CaO, alumina and quartz, were compared in a fixed-bed catalytic reactor, using a simulate high temperature coal gas. Ni-3 catalyst was found to be a quite effective catalyst for tar component (1-methylnaphthalene and benzene) conversion. Studies on the kinetics of tar component cracking and carbon combustion of catalysts were also carried out under certain conditions. A study on alkali metal vapor removal from high temperature coal gas was conducted for the purpose of reducing the corrosion of alkali metal vapor on gas turbine blades in IGCC process. NaCl was used as an alkali metal model compound, seven sorbents were screened by their effectiveness in capturing NaCl vapor at 840℃, test shows the second grade alumina; bauxite; kaoline; acidic white clay and activated Al〓O〓 present higher adsorption efficiency. They remove respectively 85. 3%, 92. 5%, 88. 0%, 92. 7% and 98. 2% of the NaCl vapor in a simulated high temperature coal gas. It is found that activated Al〓O〓 has the highest adsorption efficiency and sodium content among seven sorbents tested. In capturing time of 3h, the sodium content absorbed by activated Al〓O〓 is up to 6. 2mg/g. In addition, tests indicate the removal of NaCl with activated Al〓O〓 is a physical adsorption process.
   The experiments were then designed to simultaneously remove NH〓, coal tar component (1-methylnaphthalene) , organic sulphur (CS〓) , and HCl in high temperature coal gas by using a fixed-bed reactor. The results show Ni-3 catalyst is an effective catalyst for NH〓 and tar component decomposition, Ni-3 catalyst sulphurized is also effective for CS〓 conversion, and CNl sorbent self-prepared displays the highest adsorption capacity for HCl vapor. The gained maximum removal efficiencies are 79%, 100%, 88%, 100% respectively for NH〓, tar component, organic sulphur and HCl. Finally, a group of experiments were carried out to simultaneously remove alkali metal compound vapor and HCl. The results indicate that the bauxite, activated Al〓O〓 and special grade alumina removed respectively 79. 5%, 74. 5% and 36. 2% of the NaCl vapor, and the removal conversion of HCl vapor is up to 100%.