微藻水热提取油脂经脱氧断键制航油
|
摘要
为了提高微藻转化制航油的产物选择性,利用连续流水热装置提取微藻油脂,并经催化剂脱氧断键制航油.使用亚临界水从微藻细胞中提取得到C16～C24的脂肪酸,将脂肪酸在镍基介孔Y分子筛催化剂作用下脱氧断键得到航油产物,结果显示在390℃时航油产物的整体选择性高达50.79%,其中烷烃选择性为43.21%.微藻水热油脂的主要成分为C16脂肪酸,其经过脱羧反应生成航油主要产物C15正构烷烃.傅里叶变换红外光谱学结果显示航油产物出现C=C双键、-CHO醛基以及-CH_2烷基的吸收峰,表明Ni/Y催化剂能有效催化微藻水热油脂脱氧断键.元素分析结果显示使用水热油脂制备的航油产物中碳和氢元素质量分数高于利用藻粉制备的航油产物中碳和氢元素质量分数.量子化学计算表明,C16脂肪酸中的羧基碳原子与邻位碳原子之间的键长最短(0.080 071 nm)、键能最高(361.074 5 kJ/mol),但是Ni-H能拉长这2个碳原子之间的键长,使其更容易发生脱羧反应.
The microalgae lipids extracted by continuous flow hydrothermal equipment were deoxidized and hydrocracked under the action of catalyst to produce jet fuel, in order to improve the selectivity of jet fuel from microalgae. The C16～C24 fatty acid was extracted from the microalgae cells by subcritical water, and the fatty acid was deoxidized and hydrocracked under the action of Ni-based mesoporous Y zeolite catalyst to obtain the jet fuel product. Results showed that the selectivity of jet fuel product at 390 ℃ was 50.79%, with the alkane selectivity of 43.21%. The main component of microalgae hydrothermal lipid was palmitic acid, of which the main jet fuel product after decarboxylation was pentadecane. Fourier transform infrared spectroscopy results showed that the absorption peaks of C=C,-CHO, and-CH_2 appeared in the product, indicating that the Ni/Y catalyst can effectively promote the deoxygenation and hydrocracking of the microalgae hydrothermal lipid. Elemental analysis results showed that the mass fractions of carbon and hydrogen in the jet fuel products prepared by hydrothermal lipid were higher than those in the jet fuel products prepared by algae powder. Quantum chemistry calculation showed that the shortest bond length(0.080 071 nm) and the highest bond energy(361.074 5 kJ/mol) existed between the carbon atom in carboxyl group and the ortho carbon atom in the palmitic acid. However, Ni-H could elongate the bond length between these two carbon atoms and promote the occurance of decarboxylation reaction.
The microalgae lipids extracted by continuous flow hydrothermal equipment were deoxidized and hydrocracked under the action of catalyst to produce jet fuel, in order to improve the selectivity of jet fuel from microalgae. The C16～C24 fatty acid was extracted from the microalgae cells by subcritical water, and the fatty acid was deoxidized and hydrocracked under the action of Ni-based mesoporous Y zeolite catalyst to obtain the jet fuel product. Results showed that the selectivity of jet fuel product at 390 ℃ was 50.79%, with the alkane selectivity of 43.21%. The main component of microalgae hydrothermal lipid was palmitic acid, of which the main jet fuel product after decarboxylation was pentadecane. Fourier transform infrared spectroscopy results showed that the absorption peaks of C=C,-CHO, and-CH_2 appeared in the product, indicating that the Ni/Y catalyst can effectively promote the deoxygenation and hydrocracking of the microalgae hydrothermal lipid. Elemental analysis results showed that the mass fractions of carbon and hydrogen in the jet fuel products prepared by hydrothermal lipid were higher than those in the jet fuel products prepared by algae powder. Quantum chemistry calculation showed that the shortest bond length(0.080 071 nm) and the highest bond energy(361.074 5 kJ/mol) existed between the carbon atom in carboxyl group and the ortho carbon atom in the palmitic acid. However, Ni-H could elongate the bond length between these two carbon atoms and promote the occurance of decarboxylation reaction.
引文
[1]ZHANG C,HUI X,LIN Y,et al.Recent development in studies of alternative jet fuel combustion:progress,challenges,and opportunities[J].Renewable and Sustainable Energy Reviews,2016,54:120-138.
[2]CHISTI Y.Biodiesel from microalgae beats bioethanol[J].Trends in Biotechnology,2008,26(3):126-131.
[3]FORTIER M P,ROBERTS G W,STURN B S,et al.Life cycle assessment of bio-jet fuel from hydrothermal liquefaction of microalgae[J].Applied Energy,2014,122:73-82.
[4]ANSARI F A,GUPTA S K,SHRIWASTAV A,et al.Evaluation of various solvent systems for lipid extraction from wet microalgal biomass and its effects on primary metabolites of lipid-extracted biomass[J].Environmental Science and Pollution Research International,2017,24(18):15299-15307.
[5]ZHOU D,QIAO B Q,LI G,et al.Continuous production of biodiesel from microalgae by extraction coupling with transesterification under supercritical conditions[J].Bioresource Technology,2017,238:609-615.
[6]YANG C Y,LI R,CUI C,et al.Catalytic hydroprocessing of microalgae-derived biofuels:a review[J].Green Chemistry,2016,18(13):3684-3699.
[7]XING S Y,LV P M,WANG J Y,et al.One-step hydroprocessing of fatty acids into renewable aromatic hydrocarbons over Ni/HZSM-5:insights into the major reaction pathways[J].Physical Chemistry Chemical Physics,2017,19(4):2961-2973.
[8]MANTE O D,AGBLEVOR F A,OYAMA S T,et al.Catalytic pyrolysis with ZSM-5 based additive as cocatalyst to Y zeolite in two reactor configurations[J].Fuel,2014,117:649-659.
[9]CHRISTENSEN C H,JOHANNSEN K,TOERNQVIST E,et al.Mesoporous zeolite single crystal catalysts:diffusion and catalysis in hierarchical zeolites[J].Catalysis Today,2007,128:117-122.
[10]CHRISTENSEN C H,JOHANNSEN K,SCHMIDT I,et al.Catalytic benzene alkylation over mesoporous zeolite single crystals:improving activity and selectivity with a new family of porous materials[J].Journal of the American Chemical Society,2003,125:13370-13371.
[11]JIANG Y,FU Y,LIU L,et al.Mechanismof palladium-catalyzed decarboxylative cross-coupling between cyanoacetate salts and aryl halides[J].Science China Chemistry,2012,42(10):1493-1493.
[12]PATON R S,MASERAS F.Gold(I)-catalyzed intermolecular hydroalkoxylation of allenes:a DFTstudy[J].Organic Letters,2009,11(11):2237-2240.
[13]SHENG J,VANNELA R,RITTMANNN B E,et al.Evaluation of methods to extract and quantify lipids from Synechocystis PCC 6803[J].Bioresource Technology,2011,102(2):1697-1703.
[14]ZANUTTINI M S,PERALTA M A,QUERINI C A,et al.Deoxygenation of m-cresol:deactivation and regeneration of Pt/γ-Al2O3 catalysts[J].Industrial and Engineering Chemistry Research,2015,54(18):4929-4939.
[15]DU X H,LI X L,ZHANG H T,et al.Kinetics study and analysis of zeolite Y destruction[J].Chinese Journal of Catalysis,2016,37(2):316-323.
[2]CHISTI Y.Biodiesel from microalgae beats bioethanol[J].Trends in Biotechnology,2008,26(3):126-131.
[3]FORTIER M P,ROBERTS G W,STURN B S,et al.Life cycle assessment of bio-jet fuel from hydrothermal liquefaction of microalgae[J].Applied Energy,2014,122:73-82.
[4]ANSARI F A,GUPTA S K,SHRIWASTAV A,et al.Evaluation of various solvent systems for lipid extraction from wet microalgal biomass and its effects on primary metabolites of lipid-extracted biomass[J].Environmental Science and Pollution Research International,2017,24(18):15299-15307.
[5]ZHOU D,QIAO B Q,LI G,et al.Continuous production of biodiesel from microalgae by extraction coupling with transesterification under supercritical conditions[J].Bioresource Technology,2017,238:609-615.
[6]YANG C Y,LI R,CUI C,et al.Catalytic hydroprocessing of microalgae-derived biofuels:a review[J].Green Chemistry,2016,18(13):3684-3699.
[7]XING S Y,LV P M,WANG J Y,et al.One-step hydroprocessing of fatty acids into renewable aromatic hydrocarbons over Ni/HZSM-5:insights into the major reaction pathways[J].Physical Chemistry Chemical Physics,2017,19(4):2961-2973.
[8]MANTE O D,AGBLEVOR F A,OYAMA S T,et al.Catalytic pyrolysis with ZSM-5 based additive as cocatalyst to Y zeolite in two reactor configurations[J].Fuel,2014,117:649-659.
[9]CHRISTENSEN C H,JOHANNSEN K,TOERNQVIST E,et al.Mesoporous zeolite single crystal catalysts:diffusion and catalysis in hierarchical zeolites[J].Catalysis Today,2007,128:117-122.
[10]CHRISTENSEN C H,JOHANNSEN K,SCHMIDT I,et al.Catalytic benzene alkylation over mesoporous zeolite single crystals:improving activity and selectivity with a new family of porous materials[J].Journal of the American Chemical Society,2003,125:13370-13371.
[11]JIANG Y,FU Y,LIU L,et al.Mechanismof palladium-catalyzed decarboxylative cross-coupling between cyanoacetate salts and aryl halides[J].Science China Chemistry,2012,42(10):1493-1493.
[12]PATON R S,MASERAS F.Gold(I)-catalyzed intermolecular hydroalkoxylation of allenes:a DFTstudy[J].Organic Letters,2009,11(11):2237-2240.
[13]SHENG J,VANNELA R,RITTMANNN B E,et al.Evaluation of methods to extract and quantify lipids from Synechocystis PCC 6803[J].Bioresource Technology,2011,102(2):1697-1703.
[14]ZANUTTINI M S,PERALTA M A,QUERINI C A,et al.Deoxygenation of m-cresol:deactivation and regeneration of Pt/γ-Al2O3 catalysts[J].Industrial and Engineering Chemistry Research,2015,54(18):4929-4939.
[15]DU X H,LI X L,ZHANG H T,et al.Kinetics study and analysis of zeolite Y destruction[J].Chinese Journal of Catalysis,2016,37(2):316-323.