THE INFLUENCE OF SYNTHETIC HYDROCARBON ON LUBRICATING PROPERTIES OF FUELS FOR TURBINE ENGINES

Recently, steps have been taken to introduce synthetic hydrocarbons to aviation fuels as biocomponents. This action is an innovative change in the approach to aviation fuels. This new approach to the assessment of fuel properties requires a revision of the existing criteria for their quality assessment, including those relating to tribological properties. In the requirements for Jet fuel, only the BOCLE test simulating continuous circular motion was used to assess lubricity. Research on the use of fuels containing components with highly differentiated chemical compositions indicate that the BOCLE test may be an insufficient criterion for assessing the lubricity of fuels for aircraft turbine engines. An additional HFRR test modelling the processes accompanying the reciprocating friction that occurs in some lubricated elements of the fuel system has been proposed. This article presents the results of BOCLE and HFRR tests on a range of Jet A1 fuel mixtures and various synthetic paraffin hydrocarbons. A preliminary analysis of the observed effect of synthetic hydrocarbons on the results of both tests is presented.

EXISTING TECHNOLOGIES AND PROSPECTS FOR THE DEVELOPMENT OF SYNTHESIS OF HYDROCARBONS WITH THE USE OF COBALT CATALYSTS

Fischer-Tropsch synthesis is the main process for the production of synthetic hydrocarbons. The raw material of the process is a mixture of CO and H2, called synthesis gas. The process is carried out using catalysts based on cobalt or iron, supported on carriers of various nature. The composition of the resulting product depends on the process conditions and the catalyst used. Hydrocarbon synthesis technologies are developed and introduced into production by both foreign and some Russian companies.

Methanol / Dimethyl Ether Catalytic Transformation Over Zn-modified H-ZSN-5 Zeolite

The universally depleting reserves of traditional hydrocarbons require the development of a technology for producing synthetic hydrocarbons from renewable sources or human waste. Currently, among the possible methods for producing synthetic hydrocarbons, it is necessary to note the Fischer–Tropsch method and the method of methanol / dimethyl ether catalytic transformation. Moreover, the production of synthetic hydrocarbons from synthesis gas — the Fischer–Tropsch method, is suitable for the production of linear hydrocarbons. The hydrocarbons synthesis using methanol / dimethyl ether is suitable for the production of olefins, branched paraffins, aromatic and polyaromatic hydrocarbons. Depending on the synthesis conditions, it is possible to preferentially obtain a certain type of hydrocarbon, which significantly increases the value of this process. In this article modification of zeolite type H-ZSM-5 with zinc is studied in order to increase the yield of liquid hydrocarbons. Zeolite in acid form was treated with zinс acetate solutions of different concentrations, followed by calcination of the samples. The efficiency of the catalysts was studied in a flow tube reactor set-up, and the surface acidity of the samples was also determined. An increase in the zinc content in zeolite contributed to a decrease in the acidity of the samples and modification of their active centers. However, at high zinc content, a separate oxide phase forms, which contributes to a slight increase in acidity. Modification of zeolite with zinc leads to a decrease in the rate of transformation of dimethyl ether and the rate of liquid hydrocarbons formation. However, a general decrease in acidity and modification of zeolite with zinc contributes to a significant decrease in the amount of heavy aromatic compounds formed, with an increase in the amount of gaseous and liquid hydrocarbons being formed.