Numerical Simulation of Fouling and cleaning of ceramic membrane
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摘要: 陶瓷膜是过滤高温含尘烟气最有效的材料之一，其过滤性能和再生性能与尘粒在陶瓷膜孔道内的沉积和脱附机制相关。本文建立了不同孔隙率的陶瓷膜物理模型，然后结合连续性方程、动量方程和能量方程，设定边界条件以及沉积条件，模拟了陶瓷膜过滤和脉冲反吹时，高温烟气的流动以及尘粒的沉积与脱附过程。结果表明，过滤速度较低和陶瓷膜孔隙率较高时，易于沉积在陶瓷膜孔道内；脉冲反吹时，增加反吹压力，延长反吹时间，尘粒易于从陶瓷膜孔道脱附。采用厚度为20 mm，长度为1.5 m，孔隙率为40%的陶瓷膜管过滤温度为1000 ℃，流速为1 m·min-1，压力为0.1 MPa的含尘烟气时，反吹气压力应不低于0.3 MPa，反吹时间不短于0.02 s，尘粒脱附时间在13 s，脉冲反吹时间间隔应高于452 s。Abstract: Ceramic membrane is one of the most effective materials for hot flue gas cleaning. Its filtration performance and regeneration performance are related to the deposition and desorption mechanism of dust particles in the channel of ceramic membrane. In this paper, the physical model of ceramic membrane with different porosity is established, and then the boundary conditions and deposition conditions are set up by combining the continuity equation, momentum equation and energy equation to simulate the flow of hot flue gas and the deposition and desorption process of dust particles during ceramic membrane filtration and pulse backblowing. The results show that when the filtration velocity is low and the porosity of ceramic membrane is high, it is easy for dust particles to deposit in the ceramic membrane channel; when increases the back blowing pressure, prolongs the back blowing time during the pulse back blowing, dust particles can easily desorb from the channel of ceramic membrane. When a ceramic membrane tube with a thickness of 20 mm, a length of 1.5 m, a porosity of 40% is used to filtrate the flue gas with a filtration temperature of 1000 ℃, a flow rate of 1 m·min-1 and a pressure of 0.1 MPa, the blowback pressure should not be less than 0.3 MPa, the blowback time should be longer than 0.02 s, and the pulse blowback time interval should be more than 452 s.
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Key words:
- ceramic membrane /
- filtration /
- pulse-jet backblowing /
- deposition /
- desorption
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