粮食烘干废气多效除尘系统设计与试验

Experiment on Multi-effect Dust Removal System for Grain Drying Exhaust Gas

摘要:

针对目前粮食烘干废气处理缺乏有效处理技术和装备，影响粮食烘干产业发展的问题，开发了一种集离心沉降、团聚和喷淋作用于一体的粮食烘干废气多效除尘技术及装备。首先，通过仿真试验分析了喷淋塔气流速度、喷雾角度及喷雾压力对液滴场的影响，采用单因素试验对仿结果进行验证并确定气流速度、喷雾角及压力的适宜范围，然后以除尘效率为评价指标，进行三因素三水平二次正交回归试验，构建回归方程和响应曲面，分析气流速度、喷雾角度及喷雾压力对除尘效率的影响并进行参数优化，表明当气流速度为0.89～1.33 m/s、喷雾角度为-15°～0°、喷雾压力为1～1.5 MPa时，液滴场较均匀。最优参数组合为：气流速度0.92 m/s、喷雾角度为-8.4°、喷雾压力1.44 MPa。此时，除尘效率最高可达到96.27%。与脉冲除尘器的对比试验结果表明，经过多效除尘器处理后，粮食烘干废气平均粉尘质量浓度为5.54 mg/m3，低于脉冲除尘器的7.05 mg/m3，显著低于国家排放标准。

Abstract:

Aiming to address the lack of effective technologies and equipment for grain drying exhaust gas treatment, which affects the development of grain drying industry, a multi-effect dust removal technology and equipment integrating centrifugal sedimentation, agglomeration, and spray action for grain drying exhaust gas was developed. Initially, through simulation experiments, the effects of spray tower airflow velocity, spray angle, and spray pressure on the droplet field were analyzed. Single-factor experiments validated the simulation results and determined the appropriate range for airflow velocity, spray angle, and pressure. Subsequently, aiming for the highest dust removal efficiency, a three-factor three-level quadratic orthogonal regression experiment was carried out to construct a regression equation and response surface. The effects of airflow velocity, spray angle, and spray pressure on dust removal efficiency were analyzed for parameter optimization. It was proven that a uniform droplet field can be achieved at airflow velocities between 0.89 m/s and 1.33 m/s, spray angles between -15° and 0°, and spray pressures between 1 MPa and 1.5 MPa. The optimal parameter combination was identified as an airflow velocity of 0.92 m/s, a spray angle of -8.4°, and a spray pressure of 1.44 MPa. Experimental results showed that after optimization, the highest dust removal efficiency could reach 96.27%. Compared with a pulse dust collector, the average dust mass concentration of the grain drying exhaust gas treated by the multi-effect dust collector was 5.54 mg/m3, which was lower than 7.05 mg/m3 produced by the pulse dust collector and significantly below the national emission standard. This demonstrates that the treated grain drying exhaust gas can meet the emission standards using the developed multi-effect dust collector.