| 摘要: | 在台灣目前以火力發電為主，藉由燃煤將熱能轉變為電能，而在燃煤過程中產生大量的污染物，不僅造成後端渦輪機損壞，更會污染環境，為防治污染方面重要議題。依先前開發之除塵技術-移動式顆粒床過濾系統，經常溫下連續過濾測試，過濾效果可達98%，然而工業應用均處高溫環境下，故本研究將依據此系統進行耐高溫建置，以探討中高溫除塵效率並透過此系統進行除焦油技術開發。
藉由加熱、氣送、粉塵供應及濾材輸送系統，控制入口氣體與濾材之溫度，使系統達到高溫狀態，模擬燃燒機組後端之情形。顆粒床以濾材連續流動的方式捕集粉塵，再由後端監控系統(Process Particle Counter，PPC)監測出口端粉塵，並比較入出口粉塵濃度
進行除塵效率分析。藉由改變溫度及濾材流動速率，探討中高溫顆粒床過濾效率之影響，並由其實驗之結果進行除焦油技術開發。
實驗結果顯示，過濾效率隨溫度上升而下降，其中質量流率於 360 g/min、粉塵濃度 7500ppmw，表面風速 50cm/s，常溫下，過濾效率可達 98%以上，而 600 ℃時，過濾效率降至89%，其主要原因乃高溫下氣體黏滯力上升，使捕集機制中的慣性衝擊下降，造成過濾效率下降。
而在除焦油方面，透過改變濾材流動速度，使前端含有焦油之中高溫氣體平均溫度231.2 ℃隨濾材的流動而降溫至平均溫度 45 ℃，藉由焦油之露點溫度特性，致使焦油凝結於濾材上，以達捕集之效果，並採樣床體出口端之焦油濃度與入口端進行比較，其過濾效率可達81%。;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%. |
