Conversion processes for biofuel production

Time: Fri 2019-10-04 10.00

Location: V2, Teknikringen 76, Stockholm (English)

Subject area: Chemical Engineering Energy Technology

Doctoral student: Jerry Luis Solis Valdivia , Processteknologi, Division of Process Technology

Opponent: Prof. Mohammad Taherzadeh, University of Borås

Supervisor: Yohannes Kiros, Kemiteknik, Processteknologi

Abstract

Despite the global positive impacts of soybean-, maize- and sugarcane-based (first-generation) liquid biofuels, several drawbacks pertaining to increased use of agricultural land, causing deforestation in some countries and extensive practice of fertilizers have been observed. As a result, developing advanced (second- and third-generation) liquid biofuels have been identified as better alternatives and are considered to be of great importance in the future. These alternative biofuels will help to meet the energy demand by transition to ameliorate and fulfil the energy demand, especially in the transport sector.The actual energy demand for fossil fuels in Bolivia is unsustainable due to its continuous increase. Bolivia has its own fossil fuel resources, but these still fall short of demand, forcing the government to budget for yearly fuel imports. This situation has prompted attempts to achieve energy independence through the production of biofuels. However, it is important that Bolivian energy independence endeavours include a sustainable vision. Bolivia has great potential for local first- and second-generation liquid biofuel production. However, the intensification of liquid biofuel production should focus on second- and third-generation biofuel production to minimize direct and indirect undesired impacts.This thesis considers the development of suitable technology and procedures to produce second-generation liquid biofuels, which can be divided into biodiesel and ethanol production. The proposed biodiesel production includes the development of heterogeneous catalysts that enable the production of biodiesel from edible and non-edible oils (i.e. rapeseed, babassu, and Ricinus oils). These heterogeneous catalysts are based on gel-based mayenite and alumina supports with the co-precipitation of metal oxides of calcium, lithium, magnesium and tin. The synthesized catalysts were characterized using, N2 physisorption, X-ray powder diffraction, scanning electron microscopy, and thermogravimetric analysis (TGA). The experimental design and optimum results indicate that heterogeneous biodiesel production is feasible, being able to produce biodiesel yields ranging from 85% to 100%. Ethanol production was studied using the residues of Schinus molle seeds after the essential oil extraction process, which is available in excess in Bolivia. The biomass was characterized to elucidate its properties using high-performance liquid chromatography and TGA. The biomass was pre-treated with chemical, physical, andVIenzymatic hydrolysis to increase the fermentation yield. To obtain the highest ethanol production, two native yeast strains were isolated and characterized. By using native yeast strains, a high content of ethanol per gram of biomass was achieved. The proposed implementation of the fermentation process could result in a significant global warming potential reduction. The implementation of heterogeneous catalysts to produce biodiesel and residual lignocellulosic biomass to produce ethanol represent a great potential to supply the Bolivian fuel demand. High biodiesel and ethanol yields from second-generation feedstocks are feasible and could help reduce pollution levels and import dependency.

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