Petroleum heavy vacuum gas oil (HVGO) containing 10 wt.% of petroleum wax was hydrocracked at 390–430 °C and under the pressure of 18 MPa over a Ni W/amorphous silica-alumina catalyst in a continuous-flow fixed-bed reactor. The hydrocracking of a reference feed (neat HVGO) was carried out under the same reaction conditions. The physico-chemical properties of primary products obtained via laboratory atmospheric-vacuum distillation (heavy naphtha, middle distillates and distillation residue) were evaluated. Most products prepared from the mixed feedstock had a similar or lower density and sulfur content than the products obtained from the hydrocracking of the neat HVGO. The heavy naphtha fractions obtained from mixed feedstock contained slightly more n-alkanes and iso-alkanes and less naphthenes and aromatics. Similarly, middle distillates obtained from the mixed feedstock contained slightly more n-alkanes and less aromatics and had cetane index higher by up to 2 units.

This paper deals with the identification and determination of high-molecular-weight n-alkanes of petroleum origin using high-temperature gas chromatography (HTGC). Analysed samples, which were the concentrates of saturated hydrocarbons, differed in both the total content of n-alkanes and their distribution. They were analysed on various types of HTGC columns differing in length and inner diameter. While the determined total content of n-alkanes was comparable for all the chromatographic columns, differences were found in the efficiency of separation of n-alkanes over C₄₀ as well as in their quantitative elution.

Článek shrnuje aktuální trendy ve výzkumu a vývoji detekčních mechanismů a odpovídajících zařízení pro směsi vodíku a zemního plynu. Článek se specificky zaměřuje na principy využitelné pro detekci nebo stanovení koncentrace hořlavých plynů současně s vodíkem v různých aplikacích. Jedná se o zařízení využívaná v provozech tranzitu a distribuce zemního plynu, u koncových spotřebitelů (domácnosti, průmyslová energetická zařízení), a složkami integrovaného záchranného systému (IZS), u nichž je prioritou rychlá a přesná detekce bez vlivu křížové kontaminace. Článek poskytuje ucelené zhodnocení současného normativního rámce, především technických norem pro testování detekčních zařízení, a popisuje hlavní technologie stanovení plynů (katalytické, elektrochemické, polovodičové a optické senzory) z pohledu využitelnosti pro jednotlivé účely. U každé z metod jsou diskutovány principy funkce, současné technické a materiálové inovace a jejich limity týkající se selektivity, citlivosti a energetické náročnosti při aplikaci v komplexních plynných směsích.

The laboratory method for predicting the amount and composition of sludge accumulated during crude oil storage on the bottom of a high capacity storage tank has been developed and tested. The laboratory model of the storage tank on a scale of 1:20 was designed with the assumption of a 20-fold acceleration of the process of sedimentation of wax particles and, thus, the formation of a bottom sludge. The results of the model and industrial scale (in the high capacity tank) storage of a Russian export blend crude oil were compared and excellent agreement was found. The developed method was used to evaluate an Iran Light crude oil and a blend of crude oils, Azeri Light, and CPC. The diametrically different behaviour of the compared crude oils during their model storage was ascribed to the different paraffinic particles size distributions and rheologic properties. The correlation between the composition of the crude oil and its tendency to form a sludge at the bottom of the storage tank was not found.