黄土庙和锦界原煤及其溶胀煤的热解研究

【作者】 闫鹏；

【导师】 马晓迅；

【作者基本信息】 西北大学 ， 化学工程， 2009， 硕士

【摘要】 煤的热解反应能够得到许多有用的产物。其中气相产物为高热值的煤气,固体煤焦产物可以进行后续的燃烧或发电,而液相产物焦油中含有大量的芳烃化合物,其中的BTX等轻质芳烃具有很高的利用价值。本论文利用热失重天平和固定床反应器及在线色谱检测设备,综合考察了黄土庙原煤催化热解和加氢催化热解、黄土庙和锦界溶胀煤热解的反应性和产物收率情况。得到了以下主要结论:1.热解液相产物中BTX轻质芳烃组分在250℃左右生成,其后逐渐增大,到450℃-500℃左右达到最大值,接着到700℃左右产率降低到最小。在氢气氛下热解能够显著的促进热解的转化率和提高产物收率尤其是BTX轻质芳烃的收率。2.随着热解终温的增大,煤焦的收率逐渐降低,焦油的收率先增后减,到650℃达到最大值,气体的收率随着终温的增大而增大。3.除ZnCl₂以外,加入各种催化剂后就最终转化率来说对热解都具有促进作用。加入各种催化剂在氢气氛下进行热解能够显著的提高液相和气相的热解产物收率,且能够明显的提高液相产物中轻质芳烃的收率。4.用各种试剂及其混合溶剂对黄土庙和锦界煤进行溶胀考察,单一溶剂中NMP的溶胀效果最好,THF最差,混合溶剂中NMP+吡啶的溶胀效果最好。5.对溶胀煤在热分析天平上进行失重考察,溶胀煤的最终转化率相对原煤来说都有所增大,其中NMP溶胀煤的最终转化率最高,THF溶胀煤的转化率最低,且这些溶胀煤的溶胀率与最终转化率具有较为明显的一一对应的关系。混合溶剂中NMP+吡啶的溶胀煤具有最好的转化效果,对热解产物收率也具有较为明显的促进作用,尤其对提高产物中BTX的收率促进作用明显。6.对黄土庙煤催化热解,黄土庙溶胀煤和锦界溶胀煤热解在整个反应温度区间内进行考察,计算了在各个主要反应阶段的活化能情况。相对与原煤来说,加入催化剂后热解的脱挥发分阶段的活化能降低,说明催化剂的加入对此阶段的促进作用明显。溶胀煤在低温阶段有脱挥发分反应,活化能与溶胀效果成对应关系,溶胀率越高活化能越小。对各个阶段的活化能与补偿因子进行考察,发现其存在着较好的补偿关系。更多还原

【Abstract】 Pyrolysis of coal could gain a lot of valuable production, in which the gas production can be treated as high heat value coal gas, the solid char can be further used as burning material or to generate electricity and the liquid production contains a lot of aromatic hydrocarbons which have high value in use. In this contribution catalytic pyrolysis and hydropyrolysis of Huang Tumiao raw coal、Huang Tumiao and Jinjie solvent-swollen raw coal are investigated using TG analysis and fix-bed reactor in cooperated with on-line chromatogram, The mainly results are listed as following:1. The BTX in liquid production of pyrolysis coal appear at about 250℃, the BTX yield ratio improves with the increasing of temperature and reaches its maximal value at about 450℃-500℃, and fall to minimal value at about 700℃. Hydropyrolysis could notable increases the conversion and the production yield ratio remarkably.2. With the increasing of final pyrolysis temperature the char yield ratio reduces gradually, on the contrary the gas yield ratio increases with that, the max value of tar yield ratio is about 650℃.3. Except ZnCl₂ all of used catalysts promote the final conversion of pyrolysis. Hydropyrolysis can largely increase gas and solid yield, especially aromatic hydrocarbons yield ratio is improved dramatically.4. To investigate the swelling effect of HTM and JJ raw coal various experiments are carried out using the selected solvents and its mixture. As far as swelling effect of single solvent is considered, the NMP shows the best effect while THF is the worst case. As expected NMP and pyridine present the best performance among the mixture of the selected solvent.5. Weightlessness of swelling coal is investigated with the help of TG, compare with the original one the total conversion ratio of swelling coal is improved, whereas the swelled coal using NMP shows the best result and the swelled coal using THF is worst one, In addition it is found there exists a functional relationship between swelling ratio and total conversion ratio of swelling coal. In the mixture solvent of NMP and pyridine the swelling coal provides the best conversion effect and the yield ratio of pyrolysis production is also remarkable improved, among those the improvement of BTX yield ratio is most significant.6. Pyrolysis of HTM raw coal and swelling coal of HTM and JJ are investigated in the range of overall reactive temperature, activation energy in the main reaction phase is individual calculated, Compare with raw coal the activate energy of pyrolysis in devolatilization phase of the coal with catalyst is lower than that of raw coal, this indicates that the catalyst has significant promotion effect in this phase. At lower temperature there exists devolatilization reaction in swelling coal, and it exists a relationship between the swelling ratio and the activation energy, the higher the swelling ratio the smaller activation energy. In addition more investigation is carried out to the preexponential correlation factor k₀ and activation energy E, as a result good compensative relationship is found.更多还原