跳到主要內容 :::

年度	111	專案性質	實驗性質
專案類別	模場試驗	研究主題	整治
申請機構	國立高雄師範大學	申請系所	生物科技系(所)
專案主持人	陳士賢	職等/職稱	教授
專案中文名稱	大型石化污染場址污染土壤熱處理技術及效能評估
中文關鍵字	熱增強型土壤氣體抽除技術、高溫熱脫附法、石油碳氫化合物污染場址
專案英文名稱	Evaluation of technology and performance of thermal treatment for petroleum contaminated soils in a large contaminated site
英文關鍵字	thermally-enhanced vapor extraction technology, thermal desorption, petroleum hydrocarbon contaminated site
執行金額	1,840,000元
執行期間	2022/7/1 至 2024/6/30
計畫中文摘要	在現地整治技術選擇上，因石油碳氫化合物污染造成的土壤及地下水場址，大多會選用物理性方法、化學性處理方法或加強式生物復育法來進行整治工作。熱增強型土壤氣體抽除技術(thermally-enhanced vapor extraction technology, TEVET)是結合土壤氣體抽除技術及熱處理的污染土壤脫附技術，在真空條件下或通入載氣，通過直接或間接熱交換，使有機污染物從污染介質上得以揮發或分離，再進入氣體處理系統。TEVET發展已有二十多年，為相對成熟之整治工法，於國外實場整治應用亦具有一定之執行實績，應用TEVET來脫附不同土壤特性(如黏土、砏土及砂土)中的不同污染物(如揮發性有機物、多環芳香烴或總石油碳氫化合物(Total petroleum hydrocarbon, TPH)，以達移除污染物目的。 熱脫附(thermal desorption)處理技術為土壤整治技術之一種，係利用加熱之方式將受有機物污染土壤加熱至有機物沸點以上，使吸附於土壤中之有機物揮發成氣態後再分離處理，此方式為物理分離程序，於加熱脫附過程中並非將有機物加熱氧化，此技術基本上包含2個處理程序，第一為加熱單元又稱為旋轉窯，用以加熱待處理之物質，將物質中有機污染物揮發成氣態後分離，在加熱處理物質的過程當中，亦會將土壤中的水分含量一起蒸發，另一單元為氣狀污染物處理單元，需能將含有污染物之氣體處理至法規標準後排放至大氣，氣態污染物之處理方式，可依有機物之濃度及經濟性選擇以冷凝、吸附或燃燒之方式處理，熱脫附處理技術已經驗證可應用於處理污染土壤、底泥、污泥及濾餅等。 本計畫目的為配合國內大型石化場址整治，將國內較少使用之熱增強型土壤氣體抽除法及熱脫附法應用於離地處理石化污染土壤，評析熱增強型土壤氣體抽除技術及熱脫附法，在不同油品、不同土壤質地、不同污染程度、及不同風化程度條件下對污染土壤之總石油碳氫化合物移除效能。由於大型石化場址正在不同區域進行污染土壤開挖、現地及離地整治，透過處理場址內量體甚大且污染物種類歧異之受污染土壤，評估熱增強型土壤氣體抽除法及熱脫附法對污染土壤移除效能，蒐集操作參數及最適操作條件。 本整治技術發展之目標，第一年以建置及完備熱增強型土壤氣體抽除法及熱脫附法設施，評估污染土壤處理效能分析為主，著重設施操作參數蒐集及調整，第二年將操作參數最佳化、操作及維護成本計算，並進行熱處理技術之適用性及限制性綜合評析。藉此大型石化場址之實作經驗，整治團隊將可求得最佳操作參數，並進行設施操作及維護成本計算，整治、作為未來國內大型石化場址整治之借鏡，同時累積整治團隊未來整治產業技術及設備輸出國外之參考。 針對大型石化場址污染土壤其TPHg濃度小於3,000 mg/kg，以熱增強型土壤氣體抽除法進行復育，分項檢視三批次污染土堆其汽油類總石油碳氫化合物TPHg (C6-C9)濃度範圍介於2.35 mg/kg至182 mg/kg，三批次污染土壤處理後TPHg濃度為低於偵測極限至12.5 mg/kg，汽油類總石油碳氫化合物TPHg (C6-C9)之移除率介於90-92%，由於本場址污染多年，汽油組成分中高揮發性化合物可能經由風化作用而減少，三批次污染土壤雖然TPHg濃度相對低，但仍可觀察出熱增強型土壤氣體抽除技術對於汽油類總石油碳氫化合物TPHg (C6-C9)之移除有顯著之成效。 熱增強型土壤氣體抽除設備處理前三批次污染土壤之柴油類總石油碳氫化合物TPHd (C10-C40)濃度範圍為275 mg/kg 至3370 mg/kg，TEVET處理後分析濃度為33.3 mg/kg至4420 mg/kg，TPHd移除介於7%至57%，由三批次污染土壤分析中可觀察出熱增強型土壤氣體抽除技術對於總石油碳氫化合物TPHd (C10-C40)之移除率受到污染物沸點較高、蒸氣壓較低、揮發性較低之影響，其中部份污染土壤樣品於處理前後，對於總石油碳氫化合物TPHd (C10-C40)分析數據呈現未降低之現象，可能為土壤中污染分布不均質且污染物沸點較高、蒸氣壓較低、揮發性較低所致。 有關場址熱脫附法效能分析，多螺管式熱脫附系統在三個區域污染土壤共處理23548公噸，污染土壤總石油碳氫化合物TPH濃度範圍為2089 mg/kg至6820 mg/kg，整體處理效能顯示除3-2區單一批次TPH移除率為73.7%外，TPH移除率介於84.1%至99.9%，多螺管式熱脫附系統設備符合大型場址整治需求。有關3-1區離地高溫熱脫附系統，污染土壤進料TPH濃度最高 9,892 mg/kg，出料濃度介於113至197 mg/kg，平均每日操作量達115 B.M3(自然方)，整治期間以熱處理進行污染改善土壤數量為14,731 B.M3(自然方)，整體處理效能符合預期。 4-3及4-4區採熱脫附法處理含高濃度TPH之坋黏土質土壤，此類型土壤特性為進料時非常溼黏不易輸送，出料時則非常乾燥易引起大量揚塵，技術難度甚高，設備安裝及試車整改共歷時9個月，受限於專案完工期限，實際運作時間僅約70工作日(2022年12月~2023年2月)。全案累計處理20,200公噸，每套平均處理量為10.5公噸/小時，略低於原設計之12公噸/小時。系統整體運作順暢，故障皆可在當日排除，開機率(有效運作)可達82.0%。進料濃度介於5,870 ~36,800 mg/kg，平均值為14,700 mg/kg，典型的進料碳數分布以C12~C22為主，屬柴油範圍，出料土壤每小時分堆檢測，出料濃度則介於24~310 mg/kg，平均為82 mg/kg，TPH去除率達99.5 %以上。本計畫蒐集熱處理碳排放資訊，以供國內持續推動綠色及永續整治之參考，整體處理效能顯示熱處理方法符合大型場址整治需求，有關本計畫後續第二年工作重點，配合大型場址持續整治，將持續蒐集熱脫附處理設備數據，同時進行節能減廢措施評估及熱處理極佳化測試。
計畫英文摘要	Thermal desorption is suitable for the treatment of most volatile and semi-volatile organic pollutants in the soil, such as total petroleum hydrocarbon (TPH), chlorinated solvents, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCB), dioxins, pentachlorophenol, and mercury. In addition to the application of various types of contaminants, thermal desorption has the advantages of short treatment cycle, high efficiency in removing contaminants, high safety, low cost, reusable soil and strong pollutant recovery capabilities. The method exhibits several advantages, such as short treatment period, high efficiency, high safety, lack of secondary pollution, and recycling of impacted matrices and contaminants. The basic process includes the heating (direct or indirect) of the contaminated environmental matrix at an appropriate temperature under vacuum or into carrier gas to separate target volatile/semivolatile contaminants from the media. During ex-situ thermal desorption (ESTD), after the vaporization or sublimation processes, desorbed contaminants are condensed and consequently disposed in more concentrated volumes, activated carbon or thermal oxidizers are often used for off-gas treatment. Based on the boiling point of the target contaminants, thermal desorption can be classified as low temperature TD (LTTD) at the temperature range of 90-320C for volatile organic contaminants (VOCs), or high temperature TD (HTTD) for semivolatile organic contaminants (SVOCs) and metals at the temperature range of 320-540C. However, if the heating temperature is too high, the soil structure will be destroyed, and the organic matter in the soil and carbonate in the soil minerals will be volatilized and thermally cracked. These soils will no longer be healthy. Therefore, a low-temperature thermal desorption method such as thermally-enhanced vapor extraction technology (TE-VET) has been developed. Studies have confirmed that the low-temperature thermal de-sorption method can effectively treat low carbon range of fuel products such as gasoline and aviation fuels. TEVET was adopted in many Superfund sites or Resource Conservation and Recovery Act (RCRA) classified contaminated sites in the United States. The objective of this study is to employ thermally enhanced thermally-enhanced va-por extraction technology and thermal desorption to remediate the contaminated soils in a mega petroleum hydrocarbon contaminated site. The total area of the contaminated site is 160 hectares under intense remediation. TPH is a key evaluation indicator to establish tar-get cleanup levels for petrochemical contaminated soil. Incorporating the remediation task of the mega size petroleum hydrocarbon contaminated site, the excavated soil will be rapid-ly screened to determine which method will be used for further treatment. If the concentra-tion of TPH in soil is less than 3000 mg/kg with mainly gasoline range organics, TEVET will be used. If concentration of TPH is higher than 3000 mg/kg, TD will be used. If con-centration of TPH is less than 3000 mg/kg but in diesel range organics, soil will be distrib-uted to soil washing or bioremediation. If concentration of TPH is higher than 3000 mg/kg composing of diesel range organics, TD will be adopted. For concentation of TPH-contaminated soil below 3000 mg/kg, TEVET was employed for three batches of soil treatment. The total amount of soil treated is 3000 tons. The results indicated that TPHg decreasing from 2.35 mg/kg to 182 mg/kg to below detection limit to 12.5 mg/kg. TPHg removal ranged from 90-92%. However, TPHd removal in contaminated soil was between 7% to 57% due to contaminats with higher carbon number, lower vapor pressure to volatilize. Thermal desporption technology was performed in five major regions of the contaminated site by three types of thermal desorption systems. For System A, 23548 tons of TPH-contaminated soils were treated in opearation of 152 batches. Concentrations of TPH contaminated soils ranged from 2089 mg/kg to 6820 mg/kg. Besides one set of treatment was below 80% TPH removal, the TPH removal was 84.1% to 99.9%. For System B, 23570 tons of TPH-contaminated soils were treated with average daily capacity of 190 tons. The highest concentrstion is 9892 mg/kg. Concentration of treated soil ranged from 113 to 197 mg/kg. Overall the treated soil met the regultion requirement with residual TPH concentration below 1000 mg/kg. In total, 20200 tons of light sediment produced from soil washing facilities was treated in System C. The concentration of sediment ranged from 5870 to 36800 mg/kg due to the concentrated effect of soil washing. Concentration of treated sediment ranged from 24 mg/kg to 310 mg/kg. The average capacity is 10.5 tons/hr in System C. Greenhouse gas (GHG) emissions from five different thermal desorption facilities was estimated to be 3072.8 t CO2-eq in total using average GHG of 0.07 t CO2-eq/m3 associated with thermal desorption from previous study. It is anticipated that TPH removal efficiency by TEVET and TD can be assessed in full spectrum of variour soils contaminated by either gasoline, solvent, aviation fuel, diesel, or fuel oil. Relevant information and obtained results in the mega contaminated site prac-tice can be used as a basis for future scaling-up practice of hydrocarbon-contaminated soils remediated by ESTD in Taiwan or southeast Asia countries.