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年度	105	專案性質	實驗性質
專案類別	研究專案	研究主題	整治
申請機構	國立中央大學	申請系所	環境工程研究所
專案主持人	張木彬	職等/職稱	教授
專案中文名稱	以超臨界流體氧化技術同時處理土壤中戴奧辛、五氯酚及汞之整合性系統開發
中文關鍵字	超臨界流體氧化,戴奧辛,五氯酚,汞,整治
專案英文名稱	Development of Innovative technology for Simultaneous Removal of Dioxin, PCP and Mercury from Contaminated Soil via Supercritical Water Oxidation (SCWO)
英文關鍵字	Supercritical Water Oxidation (SCWO), PCDD/Fs, PCP, Mercury, Remediation
執行金額	1,311,000元
執行期間	2015/11/17 至 2016/11/16
計畫中文摘要	近年來國內陸續發生彰化地區戴奧辛鴨蛋事件、高雄市大坪頂與彰化段台61線非法棄置案及台南中石化安順廠週邊土壤受戴奧辛污染等事件，土壤及地下水污染議題再度受到民眾與環保單位高度的關切與重視。其中，中石化安順場址不管是在污染物形態、污染土壤量與污染物濃度方面均為國內外罕見，受污染土壤之戴奧辛(PCDD/Fs)、五氯酚(PCP)與汞含量均遠遠超過管制標準；而此種包含不同超高濃度毒性物質之複合式污染型態，是最難整治的污染場址。本研究以中石化安順場受污染土壤為對象，透過本研究群自主研發的超臨界流體氧化（SCWO）處理模組進行試驗，以評估不同操作參數條件下（包含操作溫度、操作壓力、停留時間及氧化劑添加量等）對戴奧辛、五氯酚之去除及汞回收效率進行系統性評估。在後段空氣污染控制技術方面，則搭配本研究群研發的驟冷塔進行氣相汞的回收，再藉由流動床式活性碳吸附/熱解/再生系統（發明第I424877號）將汞與戴奧辛等有機污染物同步進行吸附及破壞。此外，在廢水處理技術方面，採用鈀觸媒（Pd/Al2O3）加氫脫氯技術達到戴奧辛減量之目的，避免戴奧辛殘留於環境，達到全面解決（total solution）之境界，本研究所開發之相關技術及執行成果可提供國內相關產業於戴奧辛及汞控制上的新選擇。 初步研究結果顯示污染土壤中戴奧辛及五氯酚的去除效率隨著SCWO操作溫度、壓力、氧化劑濃度（H2O2)及反應時間的增加而提升。使用100%過氧量，反應溫度為380 oC，壓力為22MPa及停留時間為20分鐘條件下，對戴奧辛及五氯酚的破壞效率則達到99.9%以上，土壤中各污染物之殘餘濃度皆可符合法規標準（戴奧辛<1000 ng-TEQ/kg；汞<20 mg/kg）。在後段空氣污染控制方面，實驗結果顯示驟冷塔除冷凝水氣外，更可有效捕集氣流中之汞及其化合物，捕集效率介於74~96%，冷凝液中可發現液態汞珠的聚集。而廢氣通過流動床式活性碳吸附塔後，各污染物濃度皆低於我國之排放標準（五氯酚500 μg/Nm3、戴奧辛0.1 ng-TEQ/Nm3、汞50 μg/Nm3）。 本研究建立活性碳再生系統，採流動床式理念設計，活性碳吸附床中的球狀活性碳因重力往下移動至再生系統中，於無氧條件下隨著反應時間增加，對戴奧辛及五氯酚的破壞效率愈高，對吸附於活性碳之戴奧辛及五氯酚的破壞效率可達98％以上，對於總汞可達99%以上的脫除效率，由於再生系統出口端含有高濃度的汞蒸氣，可將廢氣導回驟冷塔之入口端，藉由汞珠的回收將其去除，整個系統並無含汞廢棄物或汞污泥的產生，更能達到污染減量之目的。
計畫英文摘要	Recently, various sites of contaminated soil, such as dioxin-containing eggs in Changhua, hazardous wastes in Kaohsiung and soil contaminated by dioxin and mercury in Tainan, are discovered. These issues have attracted much attention from government and general public. Among these cases, contaminated soil in An-shun site simultaneously contains extremely high concentrations of PCP, PCDD/F and mercury. Different characteristics of these contaminants have caused the difficulty for effective remediation. In this study, super-critical water oxidation (SCWO) technology is self-developed for remediation of the soil contaminated with PCDD/Fs, PCP and mercury. For efficient removal of the contaminants, relevant operating parameters including temperature, pressure, reaction time and oxidative added are tested. For well controlling pollutant emission, especially mercury, a novel quench tower is designed for recovering gas-phase mercury and condensing organic compounds. After that, the residual gaseous pollutants are further collected and destroyed via multi-layer adsorption/pyrolysis/regeneration system (Patent No I424877). Pollutants in contaminated soil, including PCDD/Fs, PCP and mercury, can be effectively destroyed and recovered via the integrated system of continuous pyrolysis system and multi-layer adsorption/pyrolysis/regeneration setup developed in this study. In addition, the wastewater collected in quench tower contains high-concentration contaminants. The chlorinated contaminants in the wastewater are further removed via hydro-dechlorination for total solution. The fruitful results obtained in this study will support the novel technology for remediation of the contaminated soil. The prelininary results indicate that the removal efficiencies of PCDD/Fs and PCP in the contaminated soil increase with increasing operating temperatures, pressure, oxidant (H2O2) added and retention time. The destruction efficiencies of PCDD/Fs and PCP in the contaminated soil are more than 99.9% with 100% of stoichiometric demand, 380oC operating temperature, 22 MPa operating pressure and 20 min. retention time. The target pollutants in the remediated soil treated with above operation parameters of SCWO system meet the regulation of Taiwan EPA (PCDD/Fs < 1,000 ng-TEQ/kg; Mercury < 20 mg/kg). Regarding the pollutants emitted from APCDs, gas-phase mercury are effectively removed by the quench tower with 74 ~ 96% removal efficiencies. The elemental mercury (Hg0) is also found in the condensed water of the quench tower. After the quench tower, the pollutants in the flue gas are further removed with multi-layer adsorption system. In the emission, all concentrations of pollutants are lower than the emission standards regulated by Taiwan EPA, including PCP < 500 μg/Nm3, PCDD/Fs < 0.1 ng I-TEQ/Nm3 and mercury < 50 μg/Nm3. The PCDD/F- and mercury-containing wastes are not generated via the SCWO system developed in this study. Hence, total solution of remediating the soil heavily contaminated with PCP, PCDD/Fs and mercury is accompolished. For BACs’ reuse, a system for BACs’ regeneration is built with moving-bed design. At oxygen-free condition (N2 as carrier gas), increasing retention time is useful to enhance destruction efficiencies of PCDD/Fs and PCP adsorbed on BACs (>98%) and removal efficiencies of mercury adsorbed on BACs (>99%). Although vaporized mercury is discharged regeneration system of BACs, exhaust of regeneration system is induced back to the flue gas before quench tower and vaporized mercury can be efficiently recovered. Finally, SCWO developed in this study can efficiently remove PCDD/Fs, PCP and mercury from contaminated soil and APCDs can also efficiently control the pollutant emission. Furthermore, secondary pollutants including emission, BACs waste and condensate from quench tower are not been discharged from SCWO+APCDs. SCWO+APCDs designed in this study is a powerful and environment-friendly remediation technology for PCDD/F and mercury removal from contaminated soil and sediment.