- 學位論文
利用鹼性吸附劑移除半導體製程中之酸排氣
Alkali Adsorbent for Removing Acidic Exhaust from Semiconductor Process
摘要
摘 要 在半導體業製程中產生無機酸性氣體具有低濃度與高流量之特性，而現階段的工廠中有九成以上都是以洗滌塔處理該氣體。但以洗滌塔去除效率不高且不易達到法規之要求。為解決此一問題，本研究利用鹼性吸附劑之設備來去除酸排氣。 本研究使用依吸附理論與規範設計出之小型固定床吸附塔及商用規格固定床吸附塔探討不同活性碳種類(AC-A為單純煤質活性碳，AC-B為含NaOH之煤質活性碳，AC-C為含KOH之煤質活性碳)與操作條件下對無機酸氣之吸附效能，藉以評選出適當之活性碳種類與得到最適操作參數。 經研究發現固定式活性碳床之壓損隨著空塔流速的增加而增加，其增加之速率呈拋物線向上增加。而含水率較高之活性碳，其壓損也隨之增加。對於酸性氣體( HCl, HF, H2SO4)而言，去除效率依序為AC-B, AC-C, AC-A。而AC-A對總碳氫化合物( total hydrocarbons, THCs)有良好之吸附能力。本研究之吸附塔經過1年實際運轉，結果顯示在固定床吸附系統使用鹼性吸附劑，可達到符合法規的標準且比洗滌塔吸收系統有更好的去除效率。
並列摘要
Abstract In the semiconductor industry, the inorganic acidic gas emitted from the production processes has the characteristics with the low concentration and the high flow rate. In the present stage, over 90% factories treat this gas using the tower scrubbers. The removal efficiency of acidic gas of tower scrubber is not high, and sometimes may not easily meet the requirements of the laws and regulations. In order to solve for this problem, this study uses the alkaline absorbent to remove the acid exhaust. This research employed the small fixed bed absorption column and commercial fixed bed absorption column that are designed according to the adsorption theory and the standards. Three activated carbons (ACs) namely, the AC-A of the pure anthrax AC, AC-B of NaOH containing anthrax AC, AC-C of KOH containing anthrax AC, were used, at various operating conditions in the adsorption experiments. The suitabilities of activated carbons were evaluated to determine the proper operating parameters. The results indicate that the pressure loss (ΔP) of fixed activated carbon bed increases with the increase of superficial velocity (empty bed velocity). The value of ΔP also increases as the moisture content of AC increases. Regarding the acidic gases (HCl, HF and H2SO4), the removal efficiencies from high to low are in the order of AC-B, AC-C and AC-A. However, the AC-A has the good adsorptive capacity regarding the total hydrocarbons (THCs). This research underwent one year plant operation. It shows that the fixed bed adsorption system using alkaline absorbent not only meets the laws and regulations standards, but also has the better removal efficiency compared to the tower scrubber absorption system.