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Biodiesel is one of the possible alternatives to diesel fuel to address the issue of fossil fuels and their impact on the environment. Substituting homogeneous transesterification with heterogeneous offers advantages such as improved catalyst and product separation, catalyst regeneration, and avoidance of saponification during the reaction. To compare homogeneous and heterogeneous transesterification, the commonly used homogenous catalyst NaOH was tested. As a heterogeneous catalyst, a mixed oxide prepared from hydrotalcite with added nickel in its structure was used. By employing suitable conditions, it is possible to achieve biodiesel through heterogeneous transesterification with a comparable FAME (Fatty acid methyl ester) content to homogeneous transesterification, meeting the standardized value of over 96.7 wt.%. Implementing a two-step heterogeneous transesterification process decreases the reaction time needed to reach the desired FAME quantity. Furthermore, following heterogeneous transesterification, glycerol as a valuable secondary product showed visibly higher purity.

Traditional liquid fuel, such as kerosene, is still the primary fuel in air transport for longer distances. Other types of propulsion, like electric batteries, fuel cells, or their combination with solar panels, are only practical for smaller aeroplanes designed for transportation purposes. In order to replace at least some fossil kerosene with waste raw materials, kerosene production from waste polyalkenes has become more important. This work investigates the possibility of using a laboratory continuous conical spouted bed reactor for the study of the production of jet fuel fraction from waste polypropylene. Optimal reaction conditions of cracking for producing high yields of hydrocarbon liquids were determined. Tested pyrolysis temperatures changed from 420 to 460°C, and CO2 flow from 0.05 to 0.2 L.min-1 at various polypropylene dosing speeds. Yields and composition of liquid and gaseous products were measured. Monomer propene dominated with almost 60 wt% in pyrolysis gases. The highest yield of jet fuel fraction, 34 wt%, was obtained at 420°C and 0.1 L.min-1 of inert gas flow. [ABSTRACT FROM AUTHOR]

Preparation of biodiesel by commonly used homogeneous transesterification produces a large amount of wastewater as well as other disadvantages like soap formation, difficult separation, dirty glycerin, and limitation of homogeneous catalyst used by the content of free fatty acids. The paper focuses on testing mixed oxide catalyst (La-Ni/MgAl) in a two-stage transesterification on various types of oils as sources for biodiesel preparation. The tested oils include commercial sunflower and corn oil, hemp oil (commonly used in cosmetics), oil extracted from spent coffee grounds, and non-food oil derived from the Camelina sativa (L.) Crantz plant. Heterogeneous transesterification offers cleaner products, easier separation, and the possibility of reusing catalysts. La-Ni/MgAl mixed oxide was obtained from hydrotalcite, prepared by co-precipitation. The novelty of this study lies in comparing the transesterification process using different types of oils and evaluating the impact of their composition on catalyst activity. In addition, a unique feature of this study is the incorporation of a two-stage transesterification process, which allows for the reaction of any unreacted oil and achieves a content of FAME in biodiesel that meets European standards. The results showed that using two-stage transesterification with mixed oxides can achieve a FAME content higher than 98 % for all tested oils. [ABSTRACT FROM AUTHOR]

Study of kinetics during hydrogenation of hydrocarbon fractions prepared by pyrolysis of waste plastic is presented. Fractions were separated by distillation from oily/wax depolymerizates obtained during pyrolysis of polyethylene and polypropylene from end-of-life vehicles at 450°C in the batch reactor. The hydrogenation of liquid fractions in the boiling range of diesel was studied as a way of upgrading before their addition into fossil diesel fuels. Optimized experimental conditions of hydrogenation and optimized conditions for chromatographic separation are reported. The success rate of hydrogenation based on the alkane/alkene ratio in the samples after hydrogenation was evaluated by chromatography and by IR spectroscopy. Finally, the selected properties prescribed in fuel standards before and after hydrogenation are compared. [ABSTRACT FROM AUTHOR]

This work presents a study on evaluation of properties of crumb rubber by selected methods. The aim of this study was verify suitability of crumb rubber as modifier for asphalt. The sieving analyze were obtain overview about distribution of grain size of crumb rubber. After sieving analyze were obtain fractions of crumb rubber with narrower distribution of grain size. These narrower fractions were subjected to selected evaluation methods. The important criterion for verification of suitability of crumb rubber was differential scanning calorimetry. This method validated that crumb rubber retain their elastic properties even than marked low temperatures. Evaluation of crumb rubber with selected methods validated, that crumb rubber is suitable additive on modified asphalt. [ABSTRACT FROM AUTHOR]