【作者】 张娜；

【导师】 丁志江；

【作者基本信息】 燕山大学 ， 环境工程， 2012， 硕士

【摘要】 目前，中国90%以上的高炉都采用湿法工艺对煤气进行回收利用，经过除尘净化后，煤气的粉尘浓度一般比较低；而且高炉煤气属于易燃易爆气体，CO等有毒气体含量高，使得在常规测量时采样口的开设、密封具有很大难度。基于上述特性，高炉煤气的粉尘含量测量装置与其他烟道气体中含尘量的测量装置有着显著区别。现有的粉尘含量测量装置中，传感器测量精度一般比较高，但是它存在零点漂移，校正比较繁琐的缺点；滤筒等速采样装置虽然操作简单，但是测量成本太高，且对低浓度粉尘的测量精度不高。因此，需要研制一种适用于低浓度高炉煤气的粉尘含量测量装置，以解决上述难题。本文首先对纤维过滤机理进行了分析，总结出了粉尘过滤过程中所受作用力的过滤效率公式；其次，分析了在测量过程中必须采用等速采样理论的原因，并详细的阐述了这一机理以及非等速采样造成的误差，为试验研究提供了理论基础。通过对粉尘浓度进行测量，得到了滤膜厚度、纤维直径、粉尘平均粒径和采样时间这四种不同因素对测定结果的影响。结果表明：滤膜的厚度对测量结果影响不大；在一定范围内，测量装置的收尘效率与滤膜中的玻璃纤维直径成反比，而与所测粉尘的平均粒径成正比，研究测量装置对粒径为10μm左右的粉尘有很高收集效率；还确定了采样的最佳时间为5min。在相同的试验条件下，通过滤膜等速采样装置和滤筒等速采样装置的重复性试验和滤膜等速采样装置不确定度的理论计算，可以得出：在这三种不同的工况条件下，滤膜等速采样装置的重复性要明显好于滤筒等速采样装置，其不确定度仅为0.73mg/m3。研究表明，通过三种测尘装置在不同方面的比较，显示了本研究提出的粉尘浓度测量装置有着明显的优越性。该装置使用玻璃纤维滤膜作为收尘滤料，不仅成本低，可以快速、精确地测量煤气中低浓度粉尘含量，而且适用广泛，操作简便、重复性好，能够很好的应用到工业现场测量更多还原

【Abstract】 At present, more than ninety percent of the blast furnace gas (BFG) is used forrecycling by wet process in China. After the purification, the dust concentration isgenerally low. In addition BFG is flammable and explosive which contains high contentpoisonous gas, for example CO, etc. These factors lead to a lot of difficulties in openingand sealing of sampling mouth. Based on the above characteristics, the measurementdevice of dust content in BFG is significantly different from other flue gas.During the existing dust content measurement devices, the precision of sensormeasurement is high, but its disadvantages are zero drift and complex calibration.Although operation of the filter cartridge isokinetic sampling device is very easy, themeasurement cost is too high and the measurement precision is not high for lowconcentration dust. Therefore, we need to develop a suitable measurement device for lowconcentration dust of BFG, in order to solve the above problems.Based on the mechanism of fiber filtration, first of all, the filtration efficiencyformula of forces on the dust during filtering process was obtained. Then, the reasons foradopting constant speed sampling theory in measurement process were analyzed. Inaddition, the mechanism and the error caused by non uniform sampling were alsodescribed in detail, which has provided theoretical basis for test study.Through the experimental research on the dust concentration measurement, theinfluence of filter membrane thickness, fiber diameter, particle size of dust and samplingtime on the measurement results has been tested. The results show that the impact of thefilter membrane thickness is not important on the measurement results. Within a certainrange, the dust collection efficiency of the device is inversely proportional to the glassfibre diameter, but proportional to the average particle size of dust. Moreover, researchshows this device has high collection efficiency for dust particles sized about10micron,with the best sampling time of5minutes. Under the same experiment conditions, throughthe repeatability test between the filtration membrane and filter cartridge isokineticsampling device, as well as the uncertainty theory calculation of filtration membraneisokinetic sampling device, it can be seen that the repeatability of filtration membrane isokinetic sampling device is better than the two others for its uncertainty was only0.73mg/m~3.The experimental researches show that this dust concentration measurement devicehas obvious advantages through the comparison among the three kinds of devices indifferent aspects. The device using glass fibre filter film as the dust filter material, not onlycan quickly and accurately measure gas of low concentration dust content with low cost,but also can be applied widely, due to its simple operation, and good repeatability,whichmake it suitable for industrial field measurement.更多还原