SCR蜂窝状脱硝催化剂磨损研究

发布时间：2017-12-27 21:28

本文关键词：SCR蜂窝状脱硝催化剂磨损研究　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：催化剂是SCR脱硝技术的核心,但是受到工艺布置位置和煤质的影响,容易造成催化剂的过度磨损,严重时引起催化剂坍塌,造成SCR脱硝活性下降,使用寿命缩短。因此研究SCR蜂窝状脱硝催化剂的磨损问题,对延长催化剂的使用寿命,减少环境问题具有一定的指导意义。本文通过实验和数值模拟的方法对SCR蜂窝状脱硝催化剂的磨损性能进行了研究,得到以下主要结果：1)采用实验的方法,研究了烟气流速、烟气入射角、颗粒粒径和浓度等关键因素对催化剂磨损的影响。实验结果显示,烟气流速对催化剂磨损影响最大,为2.93次方关系；催化剂磨损率随烟气入射角的增大而增大,对端部入口附近孔壁的磨损影响最大；催化剂磨损率随颗粒粒径和浓度增大而增大,同时当颗粒粒径和浓度分别大于20gm和70g/Nm3以后,催化剂的磨损率增长减缓。2)采用数值模拟的方法,分别对催化剂端面、孔道和尾部端面的磨损率进行了研究,结果表明,催化剂端面的磨损率最大,孔道壁面次之,尾部端面最小,在v=5m/s、dp=15.96μm、α=0°、C=55g/Nm3时,端面磨损率是孔道磨损的270倍。在端面磨损中,磨损率受孔径大小的影响较小,随烟气流速、烟气入射角的增大而增大。在孔道磨损中,烟气入射角对孔壁磨损率和磨损位置影响较大,烟气入射角为零时,除入口外,孔道壁面的磨损主要发生在孔道中后部,随着烟气入射角增大,最大磨损位置逐渐转向催化剂前部。其次,尾部端面的磨损非常小,约为端面磨损率的万分之一。最后探讨了催化剂孔径大小、整流装置布置间距、孔道堵塞对催化剂磨损的影响。结果表明,孔壁磨损率与催化剂孔径呈反比；当整流装置布置间距逐渐增大时,催化剂端面磨损率由零逐渐增大,直到稳定,而孔壁磨损率是由最大值,逐渐减小至稳定,达到稳定的间距值是150mm；当催化剂孔道堵塞时,在模拟工况下,堵塞后的催化剂孔壁磨损率为未堵塞时的1.72倍左右,对催化剂端面磨损影响不大。3)催化剂磨损主要发生在催化剂端部和孔壁,因此高尘条件下,要提高催化剂的耐磨性必须提高这两个部位的耐磨性。端面磨损主要通过端部硬化、降低烟气流速、减小烟气入射角等方面提高端面磨损强度；孔壁磨损可以通过增大催化剂孔径来提高孔壁磨损强度。此外工程中的磨损主要是因为烟气和粉尘浓度不均匀引起的局部催化剂磨损,因此在催化剂选型之后需对流场进行优化设计。基于这些研究,对水泥窑中试试验台进行了催化剂选型设计和反应器流场优化设计,目前项目已建成进入调试阶段。
[Abstract]:Catalyst is the core of SCR denitration technology, but it is easy to cause excessive wear of catalyst due to the influence of process layout location and coal quality. It seriously causes catalyst collapse, resulting in reduced activity of SCR denitrification and shortened service life. Therefore, the study of the wear of SCR honeycomb denitrification catalyst has a certain guiding significance for prolonging the service life of the catalyst and reducing the environmental problems. The paper uses the method of experiment and numerical simulation to study the wear properties of SCR honeycomb denitration catalyst, the main results are as follows: 1) using the method of experiment, study the key factors influencing the velocity of flue gas, flue gas incident angle, particle size and concentration of catalyst wear. The experimental results show that the maximum velocity of flue gas effect on catalyst wear, 2.93 Times Square; catalyst wear rate with increasing flue gas incident angle increases, the greatest impact on the end near the entrance of the hole wall wear; wear rate with the catalyst particle size and particle concentration increases, and when the particle size and particle concentration were greater than 20GM and 70g/Nm3, the wear rate of the catalyst growth slowed. 2) by the method of numerical simulation, respectively wear on the face, catalyst pore and tail end rate were studied. The results show that the wear rate of the catalyst surface, the pore wall of the tail end of the smallest, in v=5m/s, dp=15.96 m, =0 0, C=55g/Nm3 alpha, surface wear rate is 270 times pore wear. In the end face wear, the wear rate is less influenced by the size of the pore size, and increases with the increase of the velocity of smoke and the incidence of the incident angle of the flue gas. In the channel wear, the incidence angle of flue gas has great influence on the wear rate and wear location of the hole wall. When the smoke angle is zero, the wear of the main channel takes place in the back part of the channel besides the entry. With the increase of the smoke angle, the maximum wear position gradually turns to the front part of the catalyst. Secondly, the wear of the end face is very small, about 1/10000 of the end face wear rate. Finally, the influence of the size of the catalyst, the spacing of the rectifying device and the clogging of the channel on the wear of the catalyst was discussed. The results show that the wear rate of hole wall and the pore size is inversely proportional to the distance; when layout of rectifying device increases gradually, the catalyst surface wear rate increased gradually, from zero until stable, and the hole wall wear rate is determined by the maximum value decreases to a stable, stable spacing value is 150mm; when the catalyst pore blockage, in the simulated condition of catalyst pore wall after the blockage of the wear rate is about 1.72 times of that without clogging, the catalyst surface wear little effect. 3) the catalyst wear mainly occurs at the catalyst end and the hole wall. Therefore, in order to improve the wear resistance of the catalyst, the wear resistance of these two parts must be improved under high dust condition. The surface wear is mainly through the end hardening, reducing the flow rate of flue gas and reducing the incidence angle of smoke. The surface wear can increase the pore wall wear strength by increasing the pore size of the catalyst. Besides, the wear in engineering is mainly due to the local catalyst wear caused by the uneven concentration of flue gas and dust. Therefore, the flow field needs to be optimized after catalyst selection. Based on these studies, the catalyst selection design and the optimization design of the reactor flow field are carried out for the test platform in the cement kiln, and the project has already been completed into the commissioning stage.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X701

【相似文献】