Development of a System for Advanced Cleaning of Exhaust Gas from Diesel Engine Utilizing Oxidation and Reduction Reaction Coupled with Heat Recovery

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1.Preparation of catalyst particles and evaluation of their properties : To obtain the denitration catalyst, titanium dioxide(TiO_2) particles was granulated by using a binderless granulating method. Precisely, TiO_2 feed particles of 10g were fluidized at prescribed air velocities in a tapered fluidized bed granulator. The findings were as follows ; The spherical granules with the mean size ranging 150 800μm are obtained. The mean granule size can be controlled by sieving feed powder. The granule size increases with fluidizing gas velocity as well as operating time. For higher gas velocity, bimodal granule size distribution is observed. Basing upon these results, it is suggested that the granule growth process whereby the agglomerates of particles coalesces on the tapered wall concurs with the granule shaping process by rolling motions of agglomerates.Granule reinforcement experiment was carried out by spraying polyvinyl alcohol aquifer onto the granules in another tapered fluidized b … More ed. The compressive strength of granules was evaluated by using a hardness testing machine. The following results were obtained ; The compressive strength increases with the binder spraying time and reaches to the value of FCC particles. Specially, the reinforcement of coarser granules is marked.2.Study on flow properties of granules : Fluidizing properties of granules in freeboard region of fluidized bed column including solid holdup and elutriation rate were examined using FCC and char as model particles. The following findings were obtained ; Elutriation rate constant is independent of particle kinds as their terminal velocities are same. The solid holdup depends on the size of duster formed in freeboard.3.Study on denitration characteristics : Denitration experiment using TiO_2 granules were performed in freeboard region of fluidized bed equipped with an ultraviolet light source inside the bed. The following was obtained. ; Inlet nitrogen monoxide concentration of 100ppm was reduced to the off gas concentration of about 85ppm, which was kept for few minutes. It is expected that the higher power of light source and/or the higher concentration of catalyst particles in freeboard would lead to the denitration efficiency of 9O% with ease. Less