Analysis of biofuels from waste lignocellulosic materials by gas chromatography

Bc. Michal Šrámek

Master's thesis

Abstract:

In recent years, there has been a massive increase in demand for renewable energy and biofuels. This is mainly to minimise the environmental impact of greenhouse gas emissions and to improve competitiveness by reducing dependence on oil imports. Considering their renewability and sustainability, biofuels are increasingly perceived as an environmentally friendly and economically viable alternative to conventional fossil fuels. The development of new technologies in the field of biofuel production is also leading to the possibility of using various renewable resources such as vegetable oils, algae and also waste lignocellulosic biomass (LIBS), which is increasingly becoming a focus of interest. There are several methods to use waste LIBS to produce motor fuels. One of these is the Fischer-Tropsch synthesis (FTS), which allows the synthesis of hydrocarbon fractions from these waste materials with the catalyst presence, having the potential to produce motor fuels. FTS technology is becoming an important alternative to traditional fuel production from fossil sources. Prior to the actual use of the fuels produced in this way, it is necessary to analyse their chemical composition and physical properties and verify whether they meet the legislative requirements for motor fuels. The analysis of n-alkanes is a common method for characterising the chemical composition of fuels and also provides information on their quality. In this diploma thesis, realized with the collaboration of the research organization ORLEN UniCRE, gas chromatography with a flame ionization detector was used to identify and quantify linear hydrocarbon chains for individual petrol and diesel fractions obtained by FTS based on their retention times compared to reference substances. For the most suitable diesel fraction, some other properties such as density, viscosity, flash point and laboratory cetane number were evaluated. In the context of this diploma thesis, it has been shown that the synthesised hydrocarbon fractions contain different n-alkane compositions compared to commercial petrol and diesel fuels and that not all of them can be used purely as motor fuel without additional treatment. FTS petrol fractions are only suitable as additives to fossil petrol after further chemical processing. In contrast, diesel fractions can be an equivalent substitute to fossil diesel entirely. In particular, the assessment of the diesel fraction produced by hydrocracking of waxes has confirmed that this fraction can be successfully used to produce a high-quality biofuel that even overcomes fossil diesel in purity and properties. The obtained data contributes towards raising awareness that Fischer-Tropsch synthesis represents an efficient method to produce biofuels from waste lignocellulosic materials and the possibility of publishing these data in a peer-reviewed journal is predicted.

Keywords

lignocellulose, Fischer-Tropsch synthesis, waste materials, biofuels, gas chromatography

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 15. 4. 2023

Obhajoba závěrečné práce

• Obhajoba proběhla 18. 5. 2023
• Vedúci: Ing. Jan Táborský, Ph.D.
• Oponent: Jaromír Lederer, externi

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme:
Conservation and Use of Natural Resources