S Zorb脱硫过程中硅酸锌的生成规律研究

STUDY ON FORMATION OF ZINC SILICATE IN S ZrobCATALYST DURING DESULFURIZATION

针对S Zorb装置运行过程中出现不同程度的催化剂失活、破碎等问题,进行了S Zorb催化剂中硅酸锌生成规律的研究。制备锌源固定、硅源不同的系列催化剂以及硅源固定、锌源不同的系列催化剂,并在井式老化炉中采用不同温度、气氛条件对催化剂进行老化试验,结合X射线衍射物相全谱拟合(Rietveld)方法定量分析,模拟考察硅源形态及其SiO_(2)含量和ZnO粒径大小对S Zorb催化剂中硅酸锌生成的影响。结果表明:无定形SiO_(2)比有晶体结构的SiO_(2)更容易与ZnO反应生成硅酸锌,并且当硅源中的SiO_(2)为无定形状态时,硅酸锌的生成量与硅源中的SiO_(2)含量呈正相关关系;在温度800℃下,以无定形SiO_(2)作为硅源时硅酸锌收率(w)高达68.7%,而有晶体结构的纯SiO_(2)与ZnO反应时硅酸锌收率(w)为10.3%;小粒径的ZnO更容易与硅源发生反应生成硅酸锌,ZnO的粒径越大,越不容易生成硅酸锌。通过对比不同气氛环境中硅酸锌的生成情况,发现水蒸气和SO_(2)的存在均会促进硅酸锌的生成,且当SO_(2)和水蒸气共同存在时,会进一步加快硅酸锌生成。

The formation mechanism of zinc silicate in S Zorb catalyst was studied in view of deactivation and breakage of the catalyst in different degrees during the operation of the S Zorb unit.A series of catalysts with fixed zinc source,different silicon sources and different zinc source were prepared,and the aging tests were carried out in a well type aging furnace under different temperature and atmosphere conditions.The formation of zinc silicate in the catalyst was investigated by the Rietveld method,and the impact of silicon source morphology,SiO_(2) content,and ZnO particle size on the formation of zinc silicate in S Zorb catalyst was simulated.The results showed that amorphous SiO_(2) reacted with ZnO more easily than the crystalline SiO_(2) to form zinc silicate.At 800℃,the yield(w)of zinc silicate reached 68.7%when amorphous SiO_(2) was used as the silicon source,while the yield(w)of zinc silicate was 10.3%when pure SiO_(2) with crystal structure reacted with ZnO.The larger particle size of ZnO,the less zinc silicate was formed.By comparing the formation of zinc silicate in different atmospheres,it was found that the formation of zinc silicate was promoted by the presence of water vapor and SO_(2),and the formation of zinc silicate was further accelerated by the co-existence of SO_(2) and water vapor.