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.

Why the Carbon-Neutral Energy Transition Will Imply the Use of Lots of Carbon

This paper argues that electrification and gasification go hand in hand and are crucial on our pathway to a carbon-neutral energy transition. Hydrogen made from renewable electricity will be crucial on this path but is not sufficient, mainly due to its challenges related to its transport and storage. Thus, other ‘molecules’ will be needed on the pathway to a carbon-neutral energy transition. What at first sight seems a contradiction, this paper argues that carbon (C) will be an important and required chemical element in many of these molecules to achieve our carbon neutrality goal. Therefore, on top of the “Hydrogen Economy” we should work also towards a “Synthetic Hydrocarbon Economy”, implying the needs for lots of carbon as a carrier for hydrogen and embedded in products as a form of sequestration. It is crucial that this carbon is taken from the biosphere or recycled from biomass/biogas and not from fossil resources. Due to efficiency losses in capturing and converting atmospheric CO2, the production of renewable molecules will increase the overall demand for renewable energy drastically.

Elasto-viscoplastic modeling of subsidence above gas fields in the Adriatic Sea

From the analysis of GPS monitoring data collected above gas fields in the Adriatic Sea, in a few cases subsidence responses have been observed not to directly correlate with the production trend. Such behavior, already described in the literature, may be due to several physical phenomena, ranging from simple delayed aquifer depletion to a much more complex time-dependent mechanical response of subsurface geomaterials to fluid withdrawal. In order to accurately reproduce it and therefore to be able to provide reliable forecasts, in the last years Eni has enriched its 3D finite element geomechanical modeling workflow by adopting an advanced constitutive model (Vermeer and Neher, 1999), which also considers the viscous component of the deformation. While the numerical implementation of such methodology has already been validated at laboratory scale and tested on synthetic hydrocarbon fields, the work herein presents its first application to a real gas field in the Adriatic Sea where the phenomenon has been observed. The results show that the model is capable to reproduce very accurately both GPS data and other available measurements. It is worth remarking that initial runs, characterized by the use of model parameter values directly obtained from the interpretation of mechanical laboratory tests, already provided very good results and only minor tuning operations have been required to perfect the model outcomes. Ongoing R&D projects are focused on a regional scale characterization of the Adriatic Sea basin in the framework of the Vermeer and Neher model approach.

Effect of Temperature on the Composition of a Synthetic Hydrocarbon Aviation Lubricating Oil

Synthetic hydrocarbon aviation lubricating oils (SHALOs) gradually degrade over time when subjected to high temperatures, resulting in their composition and properties varying over the operation lifetime. Therefore, understanding the SHALO degradation properties by elucidating the mechanism on a molecular level, as a function of high temperature, is of interest. A SHALO was subjected to thermal treatment (TT) at 180, 200, 230, 250, 270, or 300 °C for 2 h. The chemical compositions of six TT samples and one fresh oil were analyzed by fourier transform infrared F spectroscopy, advanced polymer chromatography, and gas chromatography/mass spectrometry. Furthermore, the physicochemical properties, such as kinematic viscosity, pour point, and acid number, of seven samples were determined. The oil samples were grouped by cluster analysis (CA) using a statistical method. The SHALO was identified to comprise 20 functional groups, including comb-like alkanes, long-chain diesters, amines, phenols, and other compounds. TT at <230 °C caused partial cracking of the SHALO base oils, with a concomitant change in the antioxidant content and type, and the polycondensation reactions were dominant. The observed antioxidant changes were not obvious from TT at >230 °C. A large number of small-molecule compounds were detected, including n-alkanes and olefins. TT at 250 °C was shown to be an important threshold for the kinematic viscosity, pour point, and acid number of the samples. Below 250 °C, the sample properties were relatively stable; but at elevated TT temperatures (>250 °C), the properties were observed to dramatically degrade. As the sample color was highly sensitive to temperature, the TT temperature induced rapid and significant color changes. The CA analysis results for the oil compounds at the molecular level were in good agreement with observed changes in the physicochemical properties at the macro level.

Novel Synthetic-Based Drilling Fluid through Enzymatic Interesterification of Canola Oil

Over the years, the oil industries have avoided aromatic, naphthenic, and paraffinic oils as drilling mud base fluids principally because of their detrimental environmental issues on pelagic and benthic marine ecosystems as a result of their toxicity and nonbiodegradability coupled with the possible deterioration of the oil itself and the rubber parts of the drilling equipment because the aromatic hydrocarbons present in the oil have a tendency to dissolve/damage elastomers present in rubber. Hence, possible insights into how to chemically and/or physically produce synthetic base drilling fluids whose cuttings are nontoxic, readily biodegradable, environmentally friendly, and of nonpetroleum source become imperative. In this study, enzymatic interesterification of canola oil was done with ethanol by using enzyme lipase as catalyst under optimum conditions of temperature and pressure and the physicochemical properties of the produced ester were evaluated and compared with that of diesel and a synthetic hydrocarbon base fluid (SHBF). Results show that the specific gravity, kinematic viscosity, dynamic viscosity, and surface tension of canola oil were reduced by 5.50%, 94.74%, 95.03%, and 9.38%, respectively, upon enzymatic interesterification to conform to standard requirements. Similarly, increased |mud ability to pump fluids and possibility of cold temperature environment can be achieved with the reduction in pour point and cloud point, respectively, of the produced canola oil ester. Finally, the produced ester showed no aromatic content as confirmed from its FTIR analysis which indicates its nontoxicity, biodegradability, and environmental friendliness.