Vol 59, No 4 (2019)

Steam reforming of methane and its mixtures containing 5 and 10% propane has been studied in a membrane reactor with an industrial nickel catalyst NIAP-03-01 and a membrane in the form of 30-μm foil made of a Pd–Ru alloy. At T = 823 K and a feed space velocity of 1800 h⁻¹, the almost complete methane conversion is achieved, the selectivity for CO₂ is more than 50%, and about 80% H₂ is recovered from the reaction mixture. High conversion of CH₄ in the membrane reactor under mild conditions allows the steam reforming of its mixtures with C₂₊ alkanes to be conducted in a single process, as shown by the example of model mixtures containing C₃H₈. Under selected conditions (T = 773 or 823 K, a feed space velocity of 1800 or 3600 h⁻¹, a steam/methane ratio of 3 or 5, atmospheric pressure), almost complete C₃H₈ conversion is observed. The main “undesirable” reaction is methanation, leading to a decrease in the CH₄ conversion. In the system under study, CH₄ is formed with an increase in the feed space velocity. Methanation occurs as a result of C₃H₈ hydrocracking at a steam/feedstock ratio = 3 or the hydrogenation of CO₂ as this ratio is increased to 5. The optimal conditions for steam reforming of methane mixtures containing up to 10% C₃H₈ are T = 823 K, steam/feedstock ratio = 5, and the feed space velocity of 1800 h⁻¹. Under these conditions involving evacuation of the permeate, the feedstock conversion is complete, the selectivity for CO₂ is 50%, and more than 70% H₂ is recovered from the reaction mixture.

The catalytic decomposition of methyl formate into gaseous components in the presence of transition metal complexes, phosphine ligands, and water has been studied. It has been shown that in the presence of monometallic and bimetallic Rh/Ru catalysts, methyl formate can be converted to gas mixtures with high hydrogen content. These mixtures are suitable for use in hydroformylation, hydroaminomethylation, and hydroformylation–acetalization reactions; therefore, methyl formate may be thought of as being an alternative source of synthesis gas in oxo processes.

The most important and interesting results obtained at the Topchiev Institute of Petrochemical Synthesis of the Russian Academy of Sciences in 2008–2015 concerning dimethyl ether conversion to lower olefins in the presence of HZSM-5 zeolite catalysts have been systematized and summarized. The effects of the nature of the modifying element and catalyst steaming on the structural, acidic, and catalytic properties of the zeolite catalyst have been discussed. Some features of the influence of steam present in the feed gas mixture as a function of the nature of the modifying element have been elucidated. Data on the effect of impurities in the feed mixture (methanol and steam) have been described.

Characteristic features of the conversion of n-hexadecane, hexene-1, cyclohexane, and their mixtures over dual-zeolite catalysts for co-cracking of light and heavy fractions are considered. The maximum yield of olefins (the yield of C₂–C₄ olefins reaches 66.8 wt %) is achieved in the case of the use of hexene-1 possessing maximum reactivity under cracking conditions as a feedstock. Cotransformation of n-hexadecane and hexene-1 do not indicate the presence of any significant interaction between the components. The presence of cyclohexane in the feedstock has substantial influence on the transformation of n-hexadecane, which is due to the high hydrogen donor ability of naphthenes. It is found that the ratio of HREEY and P/HZSM-5 zeolites in the composition of the catalyst has substantial influence on the value of the interaction between the components of the feedstock. The use of hydrocarbons containing “labeled” hydrogen atoms (deuterium) makes it possible to estimate the distribution of the naphthene hydrogen between the main gaseous products.

A process flow diagram has been developed for two-stage disposal of waste, generated by deep processing of heavy petroleum residues (HPR), using the filtration combustion method to obtain heat as the final product, and optimal processing conditions have been determined. The first stage is the HPR gasification process to produce a combustible aerosol consisting of a low-calorific-value gas with a heat of combustion of about 1.4 MJ/m³ and fine droplets in an amount of up to 80% of the mass of HPR fed and similar to HPR in composition. At the second stage, the aerosol was burned to produce heat. Options for the disposal of the heavy petroleum residues as received and the same with a carbon fuel admixture (up to 5%) have been considered. It has been found that the addition of carbon fuel helps to stabilize the combustion front.