Очищення газових потоків у відцентрових фільтрах

Abstract

Дисертаційна робота присвячена розробці і дослідженням апарата нової конструкції – відцентрового фільтра, в якому поєднані два принципи очищення: відцентрової сепарації і багаторазової фільтрації через динамічний пиловий шар. В роботі наведено результати експериментальних досліджень аеродинамічних характеристик і ефективності пиловловлювання для відцентрового фільтра. Розроблено методику розрахунку відцентрового фільтра нової конструкції для отримання показників аеродинамічного опору і ефективності пиловловлювання. На основі проведеного комп’ютерного моделювання трьохвимірної моделі апарата було виявлено значний вплив центральної області сепараційної камери на показники ефективності. Результати роботи впроваджено у виробництво. Диссертационная работа посвящена разработке и исследованию аппарата новой конструкции - центробежного фильтра, в котором совмещены два принципа очистки: центробежной сепарации и многократной фильтрации через динамический пылевой слой. В работе приведены результаты экспериментальных исследований аэродинамических характеристик и эффективности пылеулавливания для центробежного фильтра. Разработано методику расчета центробежного фильтра новой конструкции для получения показателей аэродинамического сопротивления и эффективности пылеулавливания. На основе проведенного компьютерного моделирования трехмерной модели аппарата было обнаружено значительное влияние центральной области сепарационной камеры на показатели эффективности. Результаты работы внедрены в производство. The thesis is dedicated to the development and research of the apparatus of a new construction - a centrifugal filter with the channels system of closed contours, which combines two principles of purification: centrifugal separation and multiple filtration through the dynamic dust layer. The analysis of the basic directions of development and improvement of centrifugal purification technology of polydisperse streams from solid particles showed that the capture efficiency of typical dust collectors does not provide modern emission standards, but modernization leads to both: increasing of metal capacity and aerodynamic resistance of the construction and complicating the operation. The high capture efficiency can be achieved by using apparatuses with the channels system of closed contours that allow to reduce the air emissions of solid particles in 2...5 times in comparison with typical centrifugal dust collectors. However, the results of calculations based on the created mathematical models shown that studies of these devices do not fully reflect the processes occurring in them. On the basis of the analytical review of centrifugal purification of polydisperse streams from solid particles, the concept and construction of a new 8-channel centrifugal filter had been developed. The device differs from the analogs by the fact that each pair of channels is connected to an isolated bunker through the bottom of the channel and the annular gap. The method for calculating aerodynamic resistance of the centrifugal filter had been developed, that include the sum of two components: aerodynamic resistance of channels and the central area of the separation chamber. On the basis of the energy principle, the calculated dependencies with constant a and n had been obtained according to the data of laboratory-experimental studies and characteristics of materials. Multivariate numerical calculations of flue gas cleaning efficiency from SO2 had been performed and cleaning efficiency up to 50% at the contact time Ca(OH)2 with gas environment equal to 3,6 s and the rate constant equal to 47 s-1 had been achieved. A three-dimensional model of the centrifugal filter had been created and numerical and analytical research had been carried out. The pressure drop in the central area of the channel system is from 40 to 42% from the general aerodynamic resistance of the apparatus. The result of experimental research shown that the efficiency of particle capture for most experimental materials increases from the first to the second pair of channels by 20%, from the second to the third pair of channels does not change significantly and from the third to fourth pair of channels decreases by 25...30%. There had been experimentally proved that the median diameter of solid particles in elements of the apparatus varies within: from the first to the third bunkers – 2-5%, for the fourth bunker – 10-15%. Thus, the averaging of the disperse composition of solid particles in the system elements occurs in the system of channels of a centrifugal filter. Based on the analysis of obtained mathematical modeling data, experimental research, computer modeling and existing calculation methods the adequacy of the mathematical model had been confirmed. The passing of solid particles by 2-3 times compared with the analogue had been reduced due to the improvement of centrifugal filter construction in the form of successively connected curvilinear channels with the removal of particles in separate bunkers sealy insulated from each other. The purification system consisting of centrifugal filters at the enterprise «EUROCEMENT-UKRAINE» (Balakliia city) had been manufactured and installed. The testing of the aspiration system TBM № 8…10 shown that the efficiency of catching of cement dust in the centrifugal filter is in average 93% at an aerodynamic resistance of about 800 Pa. The increase in productivity by 10% without additional energy consumption for grinding had been achieved at the modernization of the aspiration system of cement mills.