生質油品氫化改質研究

Hydrogenation and Upgrading of Bio-oil

黃莉軒(Li-Xuan Huang)

指導教授 ： 張慶源

國立臺灣大學/工學院/環境工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201602310

摘要

本研究使用自行合成之硫化之鉬(MoS2)觸媒，披覆於活性氧化鋁(γ-Al2O3)顆粒表面，進行桐油改質轉製可做為航空用燃料用油之生質油品。利用觸媒填充床填充自行合成之觸媒於高溫下進行連續式反應探討溫度與觸媒種類對於桐油改質後之生質燃料油的產率與特性(酸價、碘價、密度、熱質、碳數分布及元素組成等)之影響，並找出最適反應條件，以製備生質航空燃油。
研究可概分為二階段。第一階段為MoS2觸媒製備技術之開發、第二階段為桐油氫化裂解改質試驗，利用不同溫度、工作氣體條件與不同觸媒(γ-Al2O3及MoS2/γ-Al2O3) 進行試驗。
研究結果顯示，桐油主要組成碳數為C16~C22之不飽和脂肪酸。使用γ-Al2O3為觸媒進行無氧裂解，溫度越高，裂解效果佳，在723 K時C8~C14之產物佔54%，與航空燃料油C10~C14佔71%相當接近，但其產物之H含量不符合燃料油之法規標準。若是工作氣體改用氫氣，其油品性質(酸價、碘價、熱質、密度)、裂解效果及H/C和無氧裂解比較並無明顯差異性，但產率大大提升，在723 K時從原產率28.6 vol%提升到46.5 vol%。
使用MoS2/γ-Al2O3做為催化劑，並通入氫氣進行反應，其加氫脫氧(hydrodeoxygenation, HDO)效果於較低溫時即有明顯之效果。當溫度在623 K通入氫氣反應，氫含量從桐油之10.43 wt%增加到12.67 wt%，以可符合航空燃料油之氫含量標準(13.4%)，且此生質燃料油之H/C與O/C與實際航空油經元素分析得到之值接近，而油品之酸價、熱質、密度亦符合航空燃油之燃料油品標準規範，且產率可達30 vol%，惟其碳主要組成為C14~C20。因此若是要摻配在航空油中做使用，可考慮二階段裂解反應，使碳數主要組成分佈接近航空燃料用油。

關鍵字

桐油 ； 催化裂解 ； 氫化裂解 ； 硫化鉬 ； 生質燃料油

並列摘要

This study took advantages of self-manufactured catalysts which were made by adding MoS2 on surface of γ-Al2O3 particles to conduct the updrading of tung oil. Tung oil was then carried out to bio-fuel oil (BFO) as an alternative of aviation fuels. The continuous process was designed for the cracking in a packed bed reactor filled with the catalysts at moderate to high temperatures. By varying experimental conditions, this study was conducted to investigate the effects of reaction temperature and types of catalysts on yields of the produced BFOs and their characteristics, such as acid value (AV), iodine value (IV), density (ρLO), heating value (HHV), and distribution of carbon numbers. Proper reaction conditions were determined. Finally, the characteristics of BFOs were compared with the standards of aviation fuels.
The study consists of two parts. The first part was the development of method for preparation of MoS2 based catalysts. As for the second part, under different reaction temperatures, working gases, catalysts (γ-Al2O3 and MoS2/γ-Al2O3), and methods of cracking with and without hydrogenation of tung oil were performed to produce BFO.
The main composition of tung oil is unsaturated fatty acid with carbon number between C16 to C22. After non-oxygen (nitrogen as working gas) cracking with γ-Al2O3 catalyst, the carbon number of manufactured BFO decreased to C8~C14. With increasing reaction temperature, the yield of BFO (YBFO) decreased. The effects of cracking could be evident. While the condition was set at 723 K, components of C8 to C14 in the BFO reached about 54% (estimated by simulated distillation) close to those of C10 to C14 in aviation fuels of around 71%. However, the H content of the BFO can not meet the standard of regulation. Hydrogenation-cracking was then conducted by replacing nitrogen with hydrogen as working gas. Although the other characteristics (AV, IV, ρLO, and HHV) of hydrogenation-cracked BFO were no obvious difference in comparison to those of the nitrgen-cracked BFO, the yield had a drastic rise from 28.6 vol% to 46.5 vol% at 723 K.
Further, utilizing MoS2/γ-Al2O3 catalyst for hydrogenation-cracking offered obvious improvement on hydrodeoxygenation at relatively low temperature. Hydrogenation-cracking of tung oil with MoS2/γ-Al2O3 at 623 K gave 30 vol% bio-oil yield and enhanced the hydrogen content from 10.43 wt% to 12.67 wt%, and this content was close to the hydrogen content standard of aviation fuels (13.4 wt%). With regard to other properties including acid value, density, and heating value, they could also accord with standards of aviation fuels. However, simulated distillation demonstrated that the carbon number of the BFO was around C14 to C20, which was higher than that of aviation oil (C10~C14). As a result, a two-steps cracking process is suggested to firstly saturate the hydrogen content of BFO via hydrogenation-cracking with MoS2/γ-Al2O3 and then secondly reduce the carbon number of BFO by thermal cracking with γ-Al2O3. Subsequently, the re-cracked BFO can be applied for partial blending with aviation fuels for the use of BFO.

並列關鍵字

Tung oil ； catalytic cracking ； hydrogenation-cracking ； MoS2 ； bio-fuel oil

參考文獻

39. 江勝偉. "以表面改質鉬基觸媒由合成氣產製烷類及醇類之研究"，博士論文，臺北，臺灣:臺灣大學環境工程學研究所 (2012).

46. 楊承勛. "添加醇類利用水熱法液化廢棄竹筷產製液態燃料油之研究"，碩士論文，臺北，臺灣:臺灣大學環境工程學研究所 (2015).

2. Air transpot action group. Beginner’s guide to aviation biofuels ATAG. 2011.

3. Akhtar J., Amin N.A.S. A review on process conditions for optimum bio-oil yield in hydrothermal liquefaction of biomass. Renewable and Sustainable Energy Reviews 2011; 15:1615–1624.

4. Alfred T. Fats and Fatty Oils. Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH 2002. DOI: 10.1002/14356007.a10_173.