廢棄污泥做成製程排氣除污利器之研究

Abstract

半導體工廠的污染產出無可避免，尤其在日益提升的環境保護觀念之下，改善及降低污染顯得更急迫更重要。倘若能夠利用工廠生產過程中所產生的廢棄物，加工處理後當作製程廢氣的過濾裝置，那無疑一舉兩得，使廢物變黃金，兩邊同時減廢，若還能兼具節能的效果，那將會是極為值得研究的課題。 本研究利用半導體工廠廢水廠產出的氟化鈣污泥，製成選擇性中孔洞材料與觸媒，將之置入製程排氣管道中吸附HMDS及當作廢氣焚化爐的催化劑，最終將可達成上述成效，解決半導體工廠廠務端的長期困擾。 本研究是以溶膠-凝膠法來製備奈米級選擇性中孔洞材料，由於含有CaF2，簡稱為CF-MCM，此選擇性中孔洞材料用來專門吸附HMDS及silane等高沸點VOCs（Volatile Organic Compounds）。另在製備CF-MCM的過程中加入硝酸鐵製成觸媒，簡稱為Fe-CF-MCM，用以當作焚化爐內的催化劑，不但可以降低焚化爐的燃燒溫度，還同時提升VOCs的裂解效率。 新製材料在使用前必然需要妥予實驗其適用性。取坊間最具代表性的中孔洞材料MCM-41當作比對標的，用來比較新製材料的物化特性。並架設VOCs及HMDS之連續反應實驗系統來測試新製材料的吸附功能及適用性。CF-MCM材料需具備高比表面積與高孔洞體積等特性，也需要具有良好的吸附HMDS等高沸點VOCs的能力。Fe-CF-MCM觸媒由於本身也是孔洞性材料，因此同樣必須檢視其特性，並做壽命測試。 本研究預期的效果是消納廢棄物、降低擾人的高沸點VOCs處理問題、降低沸石轉輪與VOCs焚化爐的維修負擔、同時又能達到節能效果。完成上述實驗後還必須在工廠實地做小型測試，驗證可行之後兩種新材料才能真正上線使用。

Generation of chemical wastes in semiconductor factories is inevitable. Nowadays, the circumstance of recycling chimcal wastes as reusable resources is increasing as time goes on. It becomes more urgent and more important to reduce the chemical wastes as well as mitigating the potential environment pollution generated from the wastes. However, if one could take the waste generated from the production activities of the factory and recycle it as reusable resourse use, it could not only reduce the waste but also may cut down the energy consuming. To explore the potentials, a research project was conducted to recycle the filtering waste into the usable material for processing exhaust air. In this research, the calcium fluoride sludge waste was recycled through designated selective mesoporous materials and catalysts. The sludge was generated from a wastewater plant of a semiconductor factory. The newly fabricated materials were placed in the front of Zeolite Rotor Concentrator to absorb HMDS(Hexamethyldisilazane), and the catalysts was installed inside the VOCs(Volatile Organic Compounds, VOCs）incinerator, such as RCO (Regenerative Catalytic Oxidizers) or RTO (Regenerative Thermal Oxidizers) to reduce energy consuming. To assure their suitability before use, the new made materials must be properly tested. The most common mesoporous material MCM-41 was used as the comparison standard. And then, their physicochemical properties of the new materials were compared. A simulation device for HMDS was set and VOCs absorption efficiency experiment was performed. The selective nanometer-sized porous material was made by Sol-gel solution. The mew made material contains CaF2, therefore is called “CF-MCM”. It would be used to specifically adsorb HMDS. Moreover, in the process of preparing CF-MCM, Iron nitrate nonhydrate(Fe(NO3)3·9H2O) was added and it became a catalyst, which is referred to as Fe-CF-MCM. It was used as a catalyst in the VOCs incinerator, which not only reduced the combustion temperature of the incinerator, but also enhanced the VOCs cracking effect. CF-MCM materials need to have physicochemical properties of porous, high specific surface area and uniform pore size distribution, and also have good ability to adsorb high-boiling VOCs such as HMDS. Since the Fe-CF-MCM catalyst is also a porous material, it is also necessary to examine its characteristics and conduct a life test to examine its usability. The research results demonstrate that the long-term troubles of air filtration waste can be resolved. It not only reduces the waste, but also, it may lower the maintenance loading of VOCs treatment system and decrease the usage of energy.