It is known that there are significant deposits of lignite (brown coal) in Ukraine, particularly in categories A + B + C1. At the same time, certain technical and legal obstacles limit its use as an energy carrier. Therefore, new methods of using lignite and processing its products are necessary. The latter includes humic acids. It was suggested that these acids could be used to stop road bitumens from breaking down. This is because they are antioxidants that contain functional phenolic and carboxyl groups. In particular, this article analyses the nature of the influence of humic acids on the physical and mechanical properties of road petroleum bitumen and its resistance to technological aging. It was found that at a modification temperature of 120 °C (duration-60 min., consumption of humic acids-2.0 wt.%), this additive has a slight negative effect (changes are within permissible limits) on the plastic properties of bitumen and slightly improves its elasticity. The main reason for adding humic acids to road bitumen under the specified conditions is to improve its resistance to technological aging compared to the original binder.
The possibility of effectively using carbazole as an improver of coumarone-indene resin for use as a modifier of petroleum bitumens is studied. All starting materials for the production of coumarone-indene-carbazole resin (CICR) were obtained from various products of the coal coking process. The influence of raw material composition (amount of carbazole added to an industrial indene-coumarone fraction) on resin yield and its modifying properties was studied. The optimal amounts of carbazole in the raw material were established, and it is recommended to use CICR as an adhesive additive to bitumen.
20 September 2023 in Chemistry & Chemical Technology
To synthesize resins with oxygen-containing functional groups the C9 fractions of hydrocarbon pyrolysis, heavy gasoline, and light coal tar fraction obtained from coal coking liquid products (CCLP) were used. Various types of initiators and industrial monomers were obtained using the above-mentioned non-target and/or by-products of organic raw materials processing: by the initiated oligomerization method (from C9 fractions) – petroleum polymer resins with functional groups; by radical cooligomerization (from CCLP) (with RPKV) – coumarone-indene resins with functional groups. The influence of the main factors controlling the synthesis process of resins with functional groups on their quantitative and qualitative characteristics was studied, including the process temperature, duration, and the reaction mixture composition. The structure of the synthesized resins was analyzed by IR spectroscopy, and the presence of epoxy, carboxyl, hydroxyl, and methacrylate functional groups was confirmed.
The influence of the component composition of coal batches and the final temperature of the coking process on the resistivity of coke was studied. Taking into account that the resistivity and reactivity are influenced by some common factors, such as the temperature level and coke readiness, which indicates the orderliness of its structure, the relationship between these indicators was established. The electrical resistivity can be considered a cumulative characteristic of coke properties, as evidenced by the mathematical dependencies of the change electrical resistance on the ash content, sulfur content, volatile yield, and petrographic composition. Analysis of the dependencies and their statistical evaluation indicate that the studied relationships are characterized by high values of correlation (0.6–0.84). The proposed regression equations can be recommended for optimizing the component composition and quality of production batches, given their significant impact on the resistivity of coke. This is especially relevant when coke is used in electrothermal processes, since the productivity and the electrical and thermal efficiency of the furnace depends on the resistivity of the coke in electrochemical processes in which carbon materials are used as anodes and lining elements and in the production of capacitor technology. As the resistivity test requires much less time to perform than the reactivity test, it can be considered as an alternative approach to the reactivity testing currently performed for quality control purposes.
In the presence of various catalysts (TiCl4, AlCl3, H2SO4), the process of obtaining a coumarone-indene-carbazole resin (CICR), which is produced from liquid products of coal coking, and its subsequent use for bitumen modification was investigated. The influence of the catalyst type on the yield and modifying properties of CICR (change in thermoplastic and adhesive properties of bitumen after adding the obtained resins to them) was studied. The effect of catalyst amount on the resin synthesis and subsequent modification of bitumen with the synthesized product was determined. According to the results, the optimal type and amount of the catalyst for obtaining CICR were chosen. The de-termined optimal amount of coumarone-indene-carbazole resin synthesized using the selected type of catalyst was found to have the most positive effect on the adhesive characteristics of road bitumen
The study investigates the interaction of humic acids (HAs) with road petroleum bitumen to enhance its performance and resistance to technological aging. It addresses a critical gap in understanding the modification mechanisms. The research is motivated by the need for sustainable and effective bitumen modifiers to improve the durability of asphalt pavements. The primary objective was to characterize the interaction between HA and bitumen using advanced analytical techniques, including complex thermal analysis (DTA/DTG), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results demonstrated that adding two wt.% HA to bitumen BND 70/100 increased its thermal stability, raising the onset temperature of thermo-oxidative processes from 214 to 237 °C and reducing the mass loss rate during heating from 2.5 to 1.9%·min−1. FTIR analysis revealed chemical interactions between polar groups of humic acids (e.g., –COOH, –OH) and bitumen components, forming a denser structure. SEM images confirmed a more homogeneous microstructure with fewer microcracks in the modified bitumen. Practical improvements included a higher softening point (52.6 to 54 °C) and enhanced elastic recovery (17.5 to 28.7%). However, the study noted limitations such as reduced ductility (from 58 to 15 cm) and penetration (from 78 to 72 dmm), indicating increased stiffness. The findings highlight the potential of humic acids as eco-friendly modifiers to improve bitumen’s aging resistance and thermal performance, offering practical value for extending pavement lifespan. The effective use of HA will, in turn, allow the use of Ukrainian lignite, the balance reserves of which are estimated at 2.0–2.9 billion tons, in non-fuel technologies.