高温煤气中NH_3、有机硫、HCl及焦油蒸气的同时脱除

在固定床反应器中对高温煤气中 NH3 、有机硫化物、HCl及焦油蒸气 4种污染物进行了单独和同时脱除的研究 ,其中选择 CS2 和 1 -甲基萘分别作为高温煤气中有机硫化物和焦油蒸气的模型化合物。研究得出 ,高温煤气中氨催化分解和 1 -甲基萘催化裂解的最佳催化剂同为 Ni- 3催化剂 ,CS2 转化的最佳催化剂为硫化态的 Ni- 3催化剂 ,最好的脱氯剂为 ECl。在 NH3 、CS2 、HCl及 1 -甲基萘 4种污染物同时存在时 ,将上述脱除剂组合在一起进行同时脱除实验表明 :ECl脱氯剂对 HCl的转化率和 Ni- 3催化剂对 1 -甲基萘的转化率均为 1 0 0 % ,氧化态的 Ni- 3催化剂对 NH3 的转化率和硫化态的 Ni- 3催化剂对 CS2 的转化率则随温度的升高而增加 ,在 30 0～ 550°C之间 ,氨的最大转化率为 79% ,CS2 的最大转化率为 88%

Ni nanoparticles supported on carbon as efficient catalysts for steam reforming of toluene(model tar)

This paper investigated the influences of surface properties of carbon support and nickel precursors(nickel nitrate, nickel chloride and nickel acetate) on Ni nanoparticle sizes and catalytic performances for steam reforming of toluene. Treatment with nitric acid helped to increase the amount of functional groups on the surface and hydrophilic nature of carbon support, leading to a homogeneous distribution of Ni nanoparticles. The thermal decomposition products of nickel precursor also played an important role, Ni nanoparticles supported on carbon treated with acid using nickel nitrate as the precursor exhibited the smallest mean diameter of 4.5 nm. With the loading amount increased from 6 wt% to 18 wt%, the mean particle size of Ni nanoparticles varied from4.5 nm to 9.1 nm. The as-prepared catalyst showed a high catalytic activity and a good stability for toluene steam reforming: 98.1% conversion of toluene was obtained with the Ni content of 12 wt% and the S/C ratio of3, and the conversion only decreased to 92.0% after 700 min. Because of the high activity, good stability, and low cost, the as-prepared catalyst opens up new opportunities for tar removing.

Comparison of steam-gasification characteristics of coal char and petroleum coke char in drop tube furnace

The steam-gasification reaction characteristics of coal and petroleum coke （PC） were studied in the drop tube furnace （DTF）. The effects of various factors such as types of carbonaceous material, gasification temperature （1100- 1400 ℃） and mass ratio of steam to char （0.4：1, 0.6：1 and 1：1 separately） on gasification gas or solid products were investigated. The results showed that for all carbonaceous materials studied, H2 content exhibited the largest part of gasification gaseous products and CH4 had the smallest part. For the two petroleum cokes, CO2 content was higher than CO, which was similar to Zun-yi char. When the steam/char ratio was constant, the carbon con- version of both Shen-fu and PC chars increased with increasing temperature. When the gasification temperature was constant, the carbon conversions of all char samples increased with increasing steam/char ratio. For all the steam/char ratios, compared to water gas shift reaction, char-H2O and char-CO2 reaction were further from the thermodynamic equilibrium due to a much lower char gasification rate than that of water gas shift reaction rate. Therefore, kinetic effects may play a more important role in a char gasification step than thermodynamic effects when the gasification reaction of char was held in DTF, The calculating method for the equilibrium shift in this study will be a worth reference for analysis of the gaseous components in industrial gasifier. The reactivity of residual cokes decreased and the crystal layer （L002/d002） numbers of residual cokes increased with increasing gasification temperature. Therefore, L002/d002, the carbon crystallite structure parameter, can be used to evaluate the reactivity of residual cokes.