| 摘要: | 隨著科技的進步，人們享受時代演進帶來便利的同時，更多思考如何使用更加潔淨的能源，以達到節能減碳、減少地球負擔的目的。雖然新興的再生能源日益增加，但在台灣目前仍以火力發電為主，使用煤炭轉換為電力的過程中，則會產生大量的汙染物，如粉塵、氣態汙染物及焦油等。這些汙染物若不去除乾淨，不僅會造成後方渦輪機發電機組及管線的損壞，更會造成環境的汙染，故如何防治污染為重要的課題。而根據先前開發之移動式顆粒床中高溫除塵技術，在連續粉塵過濾測試中，於常溫能達到過濾效率98%，而於高溫600℃時，過濾效率仍可達到89%。但應用於工業氣化爐時，合成氣中不只有粉塵，更包含了焦油等化學成份，因此本研究將更進一步探討移動式顆粒床過濾器應用於中高溫去除焦油。
藉由加熱、氣送及焦油氣氛系統，控制顆粒床過濾器之入口溫度，使系統達到高溫狀態，藉此模擬氣化爐之出口情況。以顆粒床過濾器於移動床模式中，所產生之前後溫度差，配合焦油露點溫度之特性，使焦油凝結於濾材中，達到焦油去除之效果，再藉由後端之氣體採樣進行分析，比較入出口濃度以計算過濾效率，藉由改變入口風速、溫度及濾材質量流率，探討中高溫顆粒床過濾器之效率影響。
實驗結果顯示，焦油過濾效率隨著溫度及表面風速的上升而下降，於焦油模組濃度50 g/Nm^3、風速1.8 m/s及濾材質量流率300 g/min進行實驗時，於150℃時可達過濾效率99.03%，而在350℃時，過濾效率仍可維持至92.3%。
;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℃. |
