牛永红, 王忠胜, 刘琨琨, 蔡尧尧, 李义科. 膨润土褐铁矿改性白云石催化松木棒气化工艺优化[J]. 农业工程学报, 2019, 35(5): 234-240. DOI: 10.11975/j.issn.1002-6819.2019.05.029
    引用本文: 牛永红, 王忠胜, 刘琨琨, 蔡尧尧, 李义科. 膨润土褐铁矿改性白云石催化松木棒气化工艺优化[J]. 农业工程学报, 2019, 35(5): 234-240. DOI: 10.11975/j.issn.1002-6819.2019.05.029
    Niu Yonghong, Wang Zhongsheng, Liu Kunkun, Cai Yaoyao, Li Yike. Processing optimization of pine rod gasification catalyzed by bentonite/limonite modified dolomite[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(5): 234-240. DOI: 10.11975/j.issn.1002-6819.2019.05.029
    Citation: Niu Yonghong, Wang Zhongsheng, Liu Kunkun, Cai Yaoyao, Li Yike. Processing optimization of pine rod gasification catalyzed by bentonite/limonite modified dolomite[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(5): 234-240. DOI: 10.11975/j.issn.1002-6819.2019.05.029

    膨润土褐铁矿改性白云石催化松木棒气化工艺优化

    Processing optimization of pine rod gasification catalyzed by bentonite/limonite modified dolomite

    • 摘要: 针对白云石催化剂在生物质催化气化过程中易碎、易产生积碳失活问题,为提高其催化活性、抗积碳和再生性能,采用固定床下吸式气化炉试验系统,以Fe-Dol-Ben(膨润土/褐铁矿改性白云石)为催化剂,松木屑废料经成型为棒状颗粒为原料,进行高温水蒸气催化气化试验。研究气化温度(700~1 000 ℃)、铁含量(质量分数为5%~20%)以及催化剂使用次数(1~4)等因素对松木棒催化气化性能及催化剂表面积碳影响。试验结果表明,水蒸气和松木棒的质量比(气料比)为1,催化剂的铁质量分数为15%,气化温度为900 ℃时气化气中氢气的体积分数达到最大值58.38%,Fe-Dol-Ben催化剂积碳量随气化温度升高逐渐减小,试验区间内1 000 ℃时达到最小值,较700 ℃减少了80%。气化气中氢气的体积分数随铁含量增加呈先增加后降低的趋势,积碳量呈先降低后增加,在铁质量分数为15%催化效果较好。Fe-Dol-Ben催化剂较相同条件下分别用膨润土及改性前白云石催化时积碳量分别减少了80.6%和53.6%。对催化剂进行再生再利用试验表明,使用后的Fe-Dol-Ben催化剂进行700 ℃煅烧再生后,其晶相与催化前基本相同,将其多次再生循环利用,随着使用次数的增加气化气中氢气的体积分数逐渐降低,催化剂的积碳量逐渐增大,使用4次并用于催化气化时氢气的体积分数仍接近50%,保持较好催化效果。综合气化效果、积碳量及经济性因素,Fe-Dol-Ben铁质量分数为15%,气化温度选取900 ℃为较理想工况。该研究可为改性白云石Fe-Dol-Ben催化剂的研制及生物质高温水蒸汽催化气化技术提供参考。

       

      Abstract: Abstract: In order to improve the catalytic activity, anti-carbon deposition and regeneration performance of dolomite catalyst which was easy to accumulate carbon and deactivate during biomass catalytic gasification, a fixed-bed suction gasifier test system was adopted in this study. Firstly, rod-shape particles were prepared from pine chips wastes using Fe-Dol-Ben (bentonite/limonite modified dolomite) as catalyst and fixed-bed downdraft gasifier as main body. An experimental system for biomass steam gasification was established. Then the high temperature steam catalytic gasification test was carried out with the above two raw materials. Finally, the effects of several factors on the catalytic gasification performance of pine wood and carbon deposition on the catalyst surface were studied. The factors affecting the catalytic gasification performance and carbon deposition on the catalyst surface were gasification temperature (temperature range is 700-1000 ℃), iron content (mass percentage range is 5%-20%) and the number of catalyst used (catalyst used number is 1-4). The results showed that the mass percentage of iron in FeDol-Ben catalyst was 15%, the gasification temperature was 900 ℃, and the volume fraction of hydrogen in gasification gas reaches the maximum of 58.38% under the condition that the mass ratio of steam to pine wood was 1. The results also showed that with the increasing of gasification temperature, the carbon deposition in FeDol-Ben catalyst decreased gradually, reaching the minimum value at 1 000 ℃, 80% lower than that at 700 ℃. In addition, the volume fraction of hydrogen in gasified gas increased first and then decreased with the increasing of iron content. At the same time, the carbon content decreased first and then increased, and the catalytic effect was better when the iron mass content was 15%. Under the same conditions as bentonite and pre-modified dolomite, the carbon deposition of Fe-Dol-Ben catalyst decreased by 80.6% and 53.6%, respectively. The experiment of catalyst regeneration and reuse showed that the crystal phase of the catalyst was basically the same as that of the pre-catalyst after the Fe-Dol-Ben catalyst regeneration at 700 ℃. The volume fraction of hydrogen in gasification gas decreased with the increasing of the number of times of regeneration, and the carbon deposition of the catalyst increased gradually. The results also showed that the volume fraction of hydrogen was still close to 50% after four times of catalytic gasification, which maintained the catalytic effect. In summary, considering the gasification effect, carbon deposition and economic factors, the optimization conditions were iron content of 15% and gasification temperature of 900 ℃. The study can provide reference for the development of bentonite/limonite modified dolomite catalyst and biomass high temperature steam catalytic gasification technology.

       

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