底饲进料循环喷动床进料与回料混合特性及影响因素

Feed and Return Material Mixing Characteristics of a Underfeed Circulating Spouted Bed and Their Influencing Factors

分别以石英砂和消石灰模拟进料和回料,对一台0.6m×15m底饲进料循环喷动床脱硫塔内颗粒混合特性进行了研究。利用石英砂和消石灰在水中溶解度的差异计算得到底饲进料与回料在不同位置的混合熵和不同高度上的混合指数,并分析不同操作参数对塔内颗粒混合行为的影响。研究结果表明:混合指数能够很好地反映塔内进料与回料颗粒的混合质量;随着流化速度的提高,塔内不同高度上的混合指数呈上升趋势;喷射速度和循环倍率对塔内尤其是反应塔底部的颗粒分布特性有明显影响,采用较高的喷射速度和循环倍率,混合指数随之上升,说明塔内颗粒的混合质量得到改善。

With quartz sand and calcium hydroxide serving as the feed and return material respectively,studied were the particle mixing characteristics of a 0.6 m×15 m underfeed circulating spouted bed in a desulfurization tower. The mixing entropies at various locations and its mixing indexes of the underfeed and return material at various elevations were calculated by utilizing the solubility difference of the quartz sand and calcium hydroxide in water,and the influence of various operating parameters on the particle mixing behavior of particles in the tower was analyzed. The research results show that the mixing index can reflect very well the mixing quality of the feed and return material particles in the tower. With an increase of the fluidization speed,the mixing indexes at various elevations in the tower assume an ascending tendency. The spouting velocity and circulation ratio conspicuously affect the particle distribution characteristics in the tower,especially at its bottom. When a relatively high spouting speed and a comparatively high circulation ratio are adopted,the mixing index will go up accordingly,indicating that the mixing quality in the tower has been improved.