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

1.催化剂颗粒的制备及其性能评价：采用无粘结剂造粒法对二氧化钛（TiO_2）颗粒进行造粒，得到了催化剂。在锥形流化床中，以10g的TiO_2为原料，在规定的空气流速下进行流化。结果表明：得到了平均粒径为150~800 μ m的球形颗粒。平均粒度可通过筛分饲料粉末来控制。颗粒尺寸随流化气速和操作时间的增加而增大。对于较高的气体速度，双峰颗粒尺寸分布观察。基于这些结果，认为颗粒团聚体在锥形壁上聚集的颗粒生长过程与团聚体滚动运动的颗粒成型过程同时发生，并在另一锥形流化床B中通过向颗粒喷射聚乙烯醇含水层进行颗粒强化实验 ...更多信息 通过使用硬度试验机评价颗粒的抗压强度。试验结果表明：随着粘结剂喷涂时间的延长，抗压强度逐渐增大，并接近FCC颗粒的抗压强度。2.颗粒的流动特性研究：以FCC和煤焦为模型颗粒，考察了流化床塔内颗粒在稀相区的流化特性，包括固含率和淘析速率。结果表明：由于颗粒的终端速度相同，因此淘析速率常数与颗粒种类无关。3.脱硝特性研究：在流化床内设置紫外光源，在流化床的超高区进行了TiO_2颗粒的脱硝实验。获得以下结果。将IOOppm的入口一氧化氮浓度降低至约85ppm的废气浓度，保持几分钟。预期较高的光源功率和/或在干舷中较高的催化剂颗粒浓度将容易地导致90%的净化效率。少

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