Study of Dependence of Softening Point on Mesophase Content of Petroleum Pitches from Heavy Pyrolysis Resin and Decantoil

Samples of petroleum pitches were obtained from heavy pyrolysis resin and decantoil (heavy gas-oil of catalytic cracking) by thermal polycondensation at atmospheric pressure, temperatures of 380–400 and 410–440°С (for resin and decantoil, respectively) and isothermal holding time of 30–480 min. Analysis of the dependence of the softening point on the mesophase content for the obtained samples showed that at the same mesophase content, decantoil pitches exhibit a lower softening point compared to pyrolysis resin pitches, for which, even at 30 % mesophase, the softening point approaches 300°C. This suggests that it is impossible to obtain pitch from pyrolysis resin with high mesophase content without preliminary preparation (for example, by hydrogenation). On the other hand, it has been shown that for pitches from decantoil, it is possible to isolate the mesophase up to 65% or more with a softening point not higher than 250°C.

Selection of Raw Materials for High-Quality Needle Coke

The aim of the study is to study the possibility of obtaining anisotropic needle coke, using various types of heavy pyrolysis resin, decantoil and a mixture of decantoil and heavy pyrolysis resin as raw materials in laboratory conditions. The coking process was carried out at a temperature of 470°C in a laboratory installation of periodic action in static conditions. A study of the influence of the composition of raw materials on such important indicators of coke as the sulfur content in coke and the assessment of the microstructure according to a special ball technique The production of cokes with a low scoring is due to the fact that under static conditions there is no directed movement of the flow of the raw material mixture, as is realized in industrial plants for delayed coking.

ВЛИЯНИЕ ТЕХНОЛОГИЧЕСКОГО РЕЖИМА УСТАНОВКИ ТЕРМИЧЕСКОГО ПИРОЛИЗА УГЛЕВОДОРОДОВ НА КАЧЕСТВЕННЫЙ СОСТАВ ТЯЖЁЛОЙ СМОЛЫ

The dependence of the yield and composition of the heavy pyrolysis resin on the initial hydrocarbon feedstock and the process conditions is investigated. The variation of technological parameters within certain limits leads to a change in the content of low molecular weight olefins in the gaseous pyrolysis products, as well as the qualitative and quantitative composition of by-product liquid products. As a result of the research, the optimum process conditions for the pyrolysis of straight-run gasoline were determined, which, with the maximum conversion of hydrocarbons to low-molecular-weight olefins, significantly increases the yield of heavy resin containing a wide fraction of naphthalene, biphenyl, indene and their alkyl derivatives. It is shown that when treating by-products containing valuable hydrocarbons as target products and combining the technological mode of pyrolysis and their composition, it is possible to achieve along with the maximum yield of low molecular weight olefins, a significant yield of heavy pyrolysis resin and qualitative changes in its composition.