Study Of Erosion On SCR Honeycomb Catalyst

The catalyst is the core of SCR de-nitration technology, but affected by the process location and coal quality, the catalyst is easy to cause excessive erosion and even collapse, which will be resulting in the activity decreased and the service life shorten. So the research on erosion of honeycomb SCR de-nitration catalyst has guiding-significance to prolong the service life of the catalyst and to reduce the environmental problem. The paper uses the method of experiment and numerical simulation to study the wear properties of SCR honeycomb catalyst, the main results are shown as following:1) This paper adopts the method of experiment to research the law of erosion of honeycomb catalyst including the influence of flow velocity, angle of incidence, particle size and particle concentration. The experimental results show that, the greatest impact on the catalyst erosion is the flue gas velocity, about 2.93 power; The erosion rate increases with the increase of the angle of incidence, which mainly effect on the wear of the front catalyst; The erosion rate increases with the increase of particle size and concentration, at the same time, when the particle size and particle concentration were greater than 20 μm and 70g/Nm3, the erosion rate of growth is slow. Meanwhile, the influence of the above factors were studied by numerical simulation, the calculation results show that numerical simulation results and experimental results have good consistency.2) This paper adopts computational fluid dynamic methods to simulate the erosion at the catalyst front, pore wall and tail, the results show that the maximum erosion rate is at the catalyst front, second is at the pore wall, the last is the tail, the erosion rate of catalyst front is 270 times of the pore surface erosion. In the front erosion, the erosion rate increases with the increase of the angle of incidence and velocity of flue gas, but not relates to pore size. In the pore erosion, the incident angle is greater impact on the pore wall erosion rate and location, when the incident angle is zero, the erosion is mainly occurred at the back of the pores, as the incident angle increases, the maximum wear position is gradually turning to the front of the pores, secondly. The tail erosion rate is very small, compared with the former two, can be ignored. Then discuss the catalyst pore size, rectifying device layer spacing, pore blockage how to effect on catalyst erosion. The investigation shows that the catalyst pore size has little effect on the catalyst front erosion rate but is inversely proportional to pore wall erosion rate; when rectifying device is arrangement, the catalyst front erosion rate is increased with the layer space increasing at first, then remains unchanged, while the pore wall erosion rate is decreased at first then remains unchanged, stable interval value is 150mm; When the catalyst pore clogging, the pore erosion rate is about 1.72 times of that without clogging, while the catalyst front-surface is little effective.3) Catalyst erosion occurs mainly at the front and the hole wall, so, if you want to improve the erosion resistance of the catalyst, shoud increase the eroscion resistance of the two parts. The front erosion improved through the front hardening, reducing the flue gas velocity, decreasing the incident angle. The pore wall erosion can be achieved by increasing the pore size of catalyst. In addition, the erosion is mainly caused by the flue gas and dust concentration unevenly distributed in project, therefore the optimized design of the flow field is important and needed. Based on these studies, the catalyst design and reactor flow optimization design is done to the cement kiln pilot. At present, the project has been built into the commissioning phase.