| dc.description.abstract | Abstract
At present, Taiwan mainly base on thermal electric generation. By burning coal into
thermal energy, a large amount of pollutants are generated in the process of burning coal, which
not only causes damage to the rear-end turbines but also pollutes the environment, it is an
important issue in the prevention and control of pollution. According to the previously
developed dust removal technology –moving granular bed filter, continuous filtration test at
room temperature, found that the filtration efficiency reach to 98%.
However, industrial applications are under high temperature environment. Therefore, this
study will develop medium and high granular bed filter based on this system to explore high
temperature filtration efficiency. In the meantime, develop tar removal technology through this
system.
By heating, gas generation, dust supply and filter material delivery systems, the
temperature of the inlet gas and the filter material is controlled to bring the system to a high
temperature state. The granular bed captures the dust in a continuous flow of the filter material,
analyzing the filtration efficiency by monitoring the concentration of outlet by process particle
counter (PPC), and then compare the dust concentration inlet and outlet. The influence of the
filtration efficiency between the temperature and flow rate was discussed, and the tar removal
technology was developed through the results of the experiment.
The experimental results showed that the filtration efficiency decreases with the increase
of temperature. On the condition of mass flow rate of 360 g/min, dust concentration 7500 ppmw
and the filtration superficial velocity of 50 cm/s, the filtration efficiency up to 98% at room
temperature, while reaching to 89% at 600 ℃. The main reason is that the viscosity of the gas
decreases at high temperatures, which causes the inertial impact in the trapping mechanism to
decrease, resulting in a decrease in filtration efficiency.
In terms of tar removal, the high temperature gas containing tar in the inlet is cooled with
III
the flow of the filter material by changing the flow rate, which makes tar condense on the filter
material because of tar dew point. Comparing the inlet and outlet concentration, found the
filtration efficiency reach to 81%. | en_US |