Thermal cracking of acid tars to asphalts as a process for utilization of refinery wastes

Characterization of acid tars

“…[1]). Kolmakov et al [2] described acid tars as a non-utilizable solid waste with resinous and viscous characteristics and varying flowability. Three processes lead to the generation of acid tars: (i) oil re-refining-the removal of metal impurities from spent lubrication oils using concentrated sulfuric acid; (ii) benzole refining-production of purified fractions of benzene, toluene and xylene (BTX) from crude benzole, a by-product of coal carbonization; and (iii) petroleum fractions refining-the use of concentrated sulfuric acid to remove unsaturated hydrocarbons and sulfur compounds from heavy lubricant fractions to produce white oil used for medicinal, cosmetic and specialized lubrication purposes [3][4][5].…”

Thin-film cracking of acid tars

“…The influence of sulfuric and sulfonic acids on the acid tar cracking process and the properties of the asphalt material obtained was studied earlier [7,9,15]. As the temperature of the acid tar thin film cracking is raised to 400°С, the proportion of resins and asphalt enes in the asphalt material increases.…”

Characterization and utilization of acid tar waste from crude benzol processing for environmental sustainability

“…[3] proposed a method for the production of paving asphalt: a three key step process which involved neutralisation of the acid tar with technical calcium oxide at temperatures between 90 and 100 o C; evaporation of water from the reaction mass at 100 to 130 o C and oxidation of the neutralised mass with air at 160 to 190 o C in a thermostatic metal reactor with stirrer. In another method by [26] acid tar was converted to asphalt using the thermal cracking method. The resulting product from this method was found to be temperature dependent such that low penetration was observed at high temperatures (460-480 0 C) when the product was exposed for 10 minutes.…”

“…When acid tars are exposed to high temperatures for more than 10 minutes coke formation is prompted instead of asphaltenes and resin which are responsible for the viscosity characteristics of the product. This type of processing requires the control of emissions since the lowest temperatures were 400 to 420 0 C [26]. Thin film cracking of acid tars at 350-400 0 C resulted in asphaltene material of 65-70%, liquid hydrocarbons of 20-25% and gas of 5-10% and at 500 0 C coke at 18% and liquid hydrocarbons 75% produced [27].…”