微藻热化学催化液化及生物油特性研究

以杜氏盐藻为原料,乙二醇为液化介质、浓硫酸为催化剂进行热化学液化反应.运用中心组合设计及响应面分析(RSA),在单因素试验的基础上建立了预测杜氏盐藻液化产率的数学模型.回归分析表明,液化温度、停留时间与催化剂用量及其交互作用对液化都有显著影响.以液化产率为响应值作响应面和等高线图,揭示了各参数交互关系.通过响应面优化,求得最佳工艺条件为:催化剂用量2.4%,液化温度170℃,停留时间33min,在此条件下液化率达到97.05%.基于生物油广泛应用的目的,对产物生物油的物理化学性质进行了研究,并结合FT-IR、~(13)C-NMR、GC-MS等技术对生物油的主要组分分布进行了分析.结果表明:生物油的主要成分为苯并呋喃酮30.43%、C14～C18有机酸甲酯23.25%和C14～C18有机酸羟乙基酯27.89%.生物油由于高的含氧量,需要进一步改性才能高端应用.

THERMOCHEMICAL CATALYTIC LIQUEFACTION OF MICROALGAE AND PROPERTIES OF BIO-OIL

The liquefaction of Dunaliella tertiolecta was investigated in ethylene glycol acidified with H_2SO_4 as catalyst. Mathematical model for predicting the liquefaction yield was set up by central composite design and response surface anal-ysis (RSA) on the basis of one-factor tests. From a regression analysis, it appears that the individual effects, as well as the interactions between operating variables all have significant effects on the liquefaction of Dunaliella tertiolecta. Such effects can be graphically verified through response surfaces and contour line plots. The liquefaction technology was opti-mized as follows: sulfuric acid content of 2.4%, the temperature of 170℃ and the time of 33min. The liquefaction yield reached 97.05% at above-mentioned conditions. To put bio-oil from thermochemical catalytic liquefaction of microalgae into wide application, physical and chemical characteristics of bio-oil were studied in detail and the main compositions of the bio-oil were characterized by FT-IR, GC-MS, ~(13)C-NMR. The major chemical compositions detected were 30.43% benzofuranone, 23.35% fatty acid methyl ester and 27.89% fatty acid hydroxyehtyl ester with long chain from C_(14) to C_(18). Upgrading of bio-oil should be processed further to improve its quality due to its high oxygen content.