Wet FGD System Critical Components Of High Abrasion Protection Countermeasures

Limestone (lime)/gypsum wet flue gas desulfurization system is the mainstream technology in China at power plant desulfurization system for the present, the slurry circulating pump as the core components of the system, its reliable operation is the key to guarantee the stability of the whole system. However, the environment of slurry circulating pump service is very bad, and the interaction of corrosion, erosion and cavitation induce the short service life. In general, valid period of full metal impeller is only around one year. Comparison of mainly protective countermeasures at present, the application of composite material could solve the wear problem of slurry pump impeller fundamentally, and it is considered to be the optimal solution. This kind of material is mainly composed of filler and matrix and other auxiliaries, as polymer matrix wear resistant composite material. Filler is composed of main wear resistant filler (SiC) and assisted modified filler (Al2O3) composition. Matrix of epoxy resin and curing agent mixed system. Beside, the other additives include coupling agent, toughening agent, thixotropic agent and diluent. The certain process with the specific device can help with producing and studying this composite material under the laboratory condition. This paper studies the mechanics of the curing agent, diluent, SiC grading scheme and solid content on composite materials and are resistant to the effects of erosion wear properties. Combined with the observation of experiment data and scanning electron microscope, this paper analyzes the mechanism of reinforcing material and failure mechanism and obtains some rules. In the first, the selection of curing agents should depend on the actual situation; for example, it is better to choice high temperature curing agent in the case of conditional situation. Secondly, the effect is more obvious when diluent agent is used in room temperature, and reactive diluents are better than non-reactive diluent. In the next, the multi level graded material properties are better in grading scheme. Fifthly, the addition of AI2O3 can improve the fluidity of slurry with high solid content, and it helps to improve solid content. The influences of the change of content have obvious rules and there is an optimal value. Under the condition of laboratory, the material in the use of high temperature curing agent, particle size of shell and solid content (83%), its performance is best. The shear strength was 11MPa, compressive strength reached 127MPa, flexural strength reached 105.27MPa, the tensile strength reaches 47.73MPa, and the specific wear rate of 0.01802g/g. This paper summarizes the field application of this kind of composite material, and the specific process and the integration of casting coating repair are given. According to theoretical calculation, the strength of the casting impeller strength meets the strength requirements, and have a certain margin of wear.