金屬觸媒催化共煉含食用油之柴油

Metal Catalysts for Co-processing Cooking-Oil With Petroleum Stock

董修齊(Siou-Ci Dong)

指導教授 ： 張仁瑞

國立中正大學/工學院/化學工程學系/碩士(2014年)

摘要

本研究主要之目的為開發用於氫化常壓蒸餾油(AOD)及同時對廢食用油進行加氫脫氧之粒狀沸石擔體鉑觸媒。其沸石擔體是以氧化矽或氧化鋁黏合劑黏合HY型沸石，經擠壓成型所得。
由於原油進料組成中普遍含有硫份及芳香烴，因此觸媒設計之主要任務是減緩由積碳及硫中毒而造成之觸媒失活。在常壓、500oC之條件下於一連續式固定床反應系統中測試觸媒進行甲苯不均化反應。我們發現相較於氧化鋁黏合劑，以氧化矽為黏合劑之觸媒其積碳生成量相對較少，觸媒老化速率也較緩慢。根據NH3-程溫脫附及程溫氧化所得積碳之特性分析結果，針對氧化矽黏合劑相對低積碳的形成，其主要是由於在觸媒造粒過程中形成較少的弱酸基。將Pt(前驅物為H2PtCl6)含浸於HY型沸石粒狀擔體上，經乾燥、煅燒及加氫還原製備鉑觸媒。另外亦添加第二金屬鈀至鉑觸媒上以增強鉑金屬欉之抗硫性。以tetralin 測試觸媒之氫化能力，而分別摻混20wt%食用油以及200ppm硫份測試觸媒之脫氧能力及抗硫性。於一連續式固定床反應系統以480psig、300oC 、WHSV=4h-1及氫油比為5.8條件下進行觸媒的抗硫性能測試；而加氫脫氧反應測試於連續式固定床反應系統以400psig、240-360oC 、WHSV=0.6h-1及氫油比為5.31條件下進行。除了NH3-TPD 及 coke-TPO特性分析技術，沸石結構、金屬欉形態及觸媒表面特性則分別藉由XRPD、EXAFS及FT-IR進行分析。綜合催化性能測試得到以下幾點結論:
1. 脂肪酸酯的催化氫解會導致paraffin的生成，而氧會與tetralin反應形成含氧化合物。
2. 鉑觸媒的抗硫性與鉑金屬欉形態有關，其中以氧化矽(Ludox)為黏合劑所製備之鉑觸媒有較高的抗硫性及較低的積碳生成速率。
3. 添加鈀至鉑觸媒可以改善其抗硫性，其中鈀前驅物及前處理條件對Pd-Pt交互作用有很重大的影響，Pd-Pt交互作用可由Pt-Pt相位校正後之傅立葉轉換EXAFS譜圖加以解釋。

關鍵字

抗硫性 ； 積碳 ； 加氫脫氧 ； 鈀-鉑雙金屬交互作用

並列摘要

The main goal of this study is to develop pellet zeolite-supported Pt catalysts for hydrogenation of atmospheric distillation Oil (ADO) concomitant with hydro-deoxygenation of waste cooking-oil. The zeolite support was pelletized by binding HY zeolite particles with silica or alumina binder and following with extrudation. Because of aromatics and sulfur containing in feed stock, the main tasks of catalyst design is to alleviate catalyst deactivation caused by coke-deposition and sulfur-poisoning. By testing the catalyst by toluene disproportionation reaction at atmospheric pressure and 500 oC in a continuous fixed bed reaction system, we found that the catalyst prepared from silica binder exhibit relatively less coke formation and thus slow deactivation rate as opposed to alumina binder. Characterized the catalysts by NH3 temperature programmed desorption (TPD) and the coke by temperature programmed oxidation (TPO), the relatively low coke formation for silica binder is mainly due to less weak acid sites formation in catalyst pellization process. The Pt catalyst was prepared by incorporating Pt precursor (H2PtCl6) into HY pellet and following by drying, calcination, and hydrogen reduction. Pd was also added to the Pt catalyst for the comparison the sulfur resistance of the catalysts. Tetralin was used as a model compound for testing hydrogenation activity, while 200 ppm sulfur containing compound and 20 wt% cooking oil were used for testing sulfur resistance and for hydro-deoxygenation activity. The test reaction of sulfur resistance was conducted and carried out in a continuous fixed bed reaction system at 480psig, 300 oC, WHSV= 4h-1, and H2/Oil=5.8； The test reaction of hydro-deoxygenation activity was conducted and carried out in a continuous fixed bed reaction system at 400psig, 240-360 oC, WHSV= 0.6h-1, and H2/Oil=5.31. Besides NH3-TPD and coke-TPO, zeolite structure, morphology of metal clusters and surface properties were characterized by XRPD, EXAFS, and FT-IR, respectively. Combined with catalytic performance tests, the following conclusions were reached:
1. Catalytic hydrogenolysis of fatty acid ester results in a formation of paraffinc compounds while oxygen react with tetralin to form oxygen-containing compounds.
2. Sulfur resistance of Pt catalysts is related to the morphology of Pt clusters and the catalysts prepared from Ludox binder exhibit higher sulfur resistance and lower coke formation rate.
3. The sulfur resistance of Pt catalysts can be improved by the addition of Pd to the catalysts, whereas Pd precursors and pretreatment conditions greatly influence the formation of Pd-Pt interactions; Pd-Pt interactions were examined by Pt-Pt corrected Fourier transform of EXAFS spectra.

並列關鍵字

sulfur resistance ； coke ； hydrodeoxygenation ； Pd-Pt bimetallic interactions

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