A Study of the Tar Removal Efficiency of Moving Granular Bed Filter

• Main Authors: Cheng-En Liao, 廖承恩
• Other Authors: Shu-San Hsiau
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/7byx65

碩士 === 國立中央大學 === 機械工程學系 === 107 === While enjoying the convenience resulted from the technological advances, human beings also ponder on how to use cleaner energy, with an eye to reducing the carbon production. Although the types of renewable energy are increasing, thermal power generation still ranks as the primary way of power generation in Taiwan. The conversion of coal into electricity also produces a large amount of pollutants, such as dust, tar, and other gaseous pollutants. If not removed, these pollutants will not only do damage to the turbine generators and pipelines in the rear, but also cause environmental pollution. Therefore, the development of dust removal technology has become an issue of vital interest. According to current tar removal technology at high temperature, the moving granular bed filter exhibits a filtration efficiency of 89% at 600℃ in the continuous dust filtration tests. However, when this technology is applied to the industrial gasifier, in the syngas the tar is still detected. This research attempts to explore how a moving granular bed filter could be used to remove tar at high temperature. In order to simulate the outlet of the gasifier, a heater, an air delivery system and a tar generation system are utilized to bring the granular bed filter to a high temperature state. In the moving bed mode, the syngas is cooled to the dew point temperature by the GBF and the tar is condensed in the filter, bringing about an effect of tar removal. As for the filtration efficiency, the concentration of inlet and that of outlet are analyzed and compared. By altering the inlet temperature, the inlet superficial velocity, and mass flow rate of the filter, the factors affecting the overall efficiency of GBF at medium and high temperature are to be further investigated. The research results show that the filtration efficiency lowers as the inlet temperature and inlet superficial velocity rise. Under the circumstance of a tar concentration of 50 g/Nm^3, an inlet superficial velocity at 1.8 m/s, and a mass flow rate at 300 g/min, a tar removal efficiency of 99.03% is achieved at 150℃, and it could be maintained at 92.3% at 350℃.