Ewa Śliwka

Conversion of cresols and naphthalene in the hydroprocessing of three-component model mixtures simulating fast pyrolysis tars

The hydroconversion of o-, m- and p-cresols in three-component model mixtures with naphthalene and n-hexadecane was investigated over a CoMoAl2O3 catalyst at 360°C, a hydrogen pressure of 7 MPa and a reaction time of 60 min. The results were compared with those obtained for cresols and naphthalene as single model compounds. A lower efficiency of cresol hydrodeoxygenation as well as naphthalene hydrogenation in the mixtures was found than in the conversion of the single compounds. Conversion mechanisms of cresols in the mixtures with naphthalene are considerably more complex than for individual components. Beside typical catalytic reactions, they include radical reactions in which tetralin, formed by naphthalene hydrogenation, participates as a labile-hydrogen source. The cresol reaction products in such systems include phenol, xylenols, xylenes and dimethycyclohexanes, i.e. compounds essentially absent in hydroconversion of cresols as single substances. Under the experimental conditions, the hydrodeoxygenation efficiency of the cresol isomers decreases in the sequence: para > meta > ortho.

Oxygen elimination in the process of non-catalytic liquefaction of brown coal☆

Abstract The effects of process temperature, pressure and reaction time on brown coal conversion rate and accompanying degree and form of oxygen elimination were evaluated in a series of autoclave runs. The degree of total oxygen elimination depends mainly on the process temperature. Increase of temperature favours formation of H2O.

Reactive oxygen groups in low-temperature tars from low-rank coal

Abstract Two Polish brown coals and two low-rank bituminous coals were subjected to low-temperature rapid pyrolysis to obtain tars. The reactive (phenolic, carbonyl and carboxyl) oxygen groups in the oils, asphaltenes and preasphaltenes of the tars were quantified. The amount of reactive oxygen groups in the bituminous coal tars was twice that in the brown coal tars. Phenolic groups predominated. Reactive oxygen in the oil fractions of the bituminous coal tars represented 80% of the total oxygen, and in the asphaltenes 90–100%. Non-reactive oxygen occurred in greater proportions in the preasphaltenes.

Effect of Surfactants on the Biodegradation of Petroleum Hydrocarbons

This paper focuses on the influence of Rokafenol N9-surfactant on the degree of biodegradation of diesel oil fraction (295–310°C). The diesel oil was a product of atmospheric distillation of Russian crude oil from the “Ural” oil field. It contained hydrocarbons characteristically hardly susceptible to biodegradation and of high toxicity. Bioindication tests carried out by the Ames test showed that it contained compounds of potential mutagenic and carcinogenic properties. The effectiveness of the diesel oil biodegradation was analyzed both for the individual native strain and their consortium. Biodegradation of diesel oil was most effective in the culture of bacteria mixture. It was confirmed that introducing a 0.5g/dm3 concentration of the surfactant Rokafenol N9 increased the effectiveness of biodegradation from 36 to 81 %mas.

PLASMA GASIFICATION OF WASTE PLASTICS

The article presents the process of obtaining liquid fuels and fuel gas in the process of plasma processing of organic materials, including waste plastics. The concept of plasma pyrolysis of plastics was presented and on its basis a prototype installation was developed. The article describes a general rule of operating the installation and its elements in the process and basic operation parameters determined during its startup. Initial results of processing plastics and the directions of further investigations are also discussed. The effect of the research is to be the design of effective technology of obtaining fuels from gasification/pyrolysis of organic waste and biomass.