The selective removal of nitrogen-containing compounds from oil and oil fractions is of interest because of the potential deleterious impact of such compounds on products and processes. Problems caused by nitrogen-containing compounds include gum formation, acid catalyst inhibition and deactivation, acid–base pair-related corrosion, and metal complexation. A brief overview of the classes of nitrogen compounds found in oil is provided. The review of processes to remove nitrogen from oil emphasizes studies that investigated denitrogenation of industrial feedstocks, such as refinery fractions, heavy oils, and bitumens. The main topics covered are hydrotreating, liquid–liquid phase partitioning, solvent deasphalting, adsorption, chemical conversion followed by separation, and microbial conversion. Chemical conversion processes include oxidative denitrogenation, N-alkylation, complexation with metal salts, and conversion in high-temperature water. There are many processes for denitrogenation by separation of t...

Nitrogen Removal from Oil: A Review

Tribological behavior of nano TiO2 as an additive in base oil

The structure and friction of fatty acid surfactant films adsorbed on iron oxide surfaces lubricated by squalane are examined using large-scale molecular dynamics simulations. The structures of stearic acid and oleic acid films under static and shear conditions, and at various surface coverages, are described in detail, and the effects of unsaturation in the tail group are highlighted. At high surface coverage, the measured properties of stearic acid and oleic acid films are seen to be very similar. At low and intermediate surface coverages, the presence of a double bond, as in oleic acid, is seen to give rise to less penetration of lubricant in to the surfactant film and less layering of the lubricant near to the film. The kinetic friction coefficient is measured as a function of shear rate within the hydrodynamic (high shear rate) lubrication regime. Lubricant penetration and layering are observed to be correlated with friction coefficient. The friction coefficient with oleic acid depends only weakly on...

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Structure and friction of stearic acid and oleic acid films adsorbed on iron oxide surfaces in squalane.

Purification of liquid fuel from nitrogenated compounds is of interest in order to protect the automotive engines and the environment from its harmful effects represented in corrosion, formation of...

Applicable Strategy for Removing Liquid Fuel Nitrogenated Contaminants Using MIL-53-NH2@Natural Fabric Composites

To improve the oil-solubility of nanoparticles, a new technology was used to prepare a kind of lubricant containing titanium dioxide (TiO2) nanoparticles. The microstructures of the prepared nanoparticles were characterized via transmission electron microscope (TEM) and infrared spectroscopy (IR). Tribological properties of TiO2 nanoparticles used as an additive in base oil were evaluated using four-ball tribometer and ball-on-disk tribometer. In addition, the worn surface of the steel ball was investigated via polarized microscopy (PM) and X-ray photoelectron spectroscopy (XPS). The TiO2 nanoparticles can be completely well-dispersed in the base oil under a new process (NP), which has no significantly negative effect on the anti-oxidation property. The results of the tribological tests show that TiO2 nanoparticles under the NP show a better anti-wear property and friction-reducing property in base oil compared to TiO2 nanoparticles under the tradition process (TP). The main aim of this paper lies in solving with the oil-solubility problem through the combination effect of surface modification and special blend process of lubricating oil. This method was first used to prepare lubricant containing TiO2 nanoparticles and then used as additives in engine oil, gear oil, and other industrial lubricants. At the same time, tribological properties of TiO2 nanoparticles in base oil as a lubricating additive were also studied.

https://www.mdpi.com/2075-4442/4/2/12/pdf

Tribological Properties of the Lubricant Containing Titanium Dioxide Nanoparticles as an Additive

Preparation and tribological properties of stearic acid-modified hierarchical anatase TiO2 microcrystals

Removal of basic nitrogen compounds from straight-run diesel with metallic ion/complexing extraction agent was investigated. The refining process experiments were examined in order to determine the optimal experimental conditions. The results showed that the content of basic nitrogen compounds in straight-run diesel was decreased; the appearance, color, and existent gum of diesel oil were improved greatly. Removal rate and feed oil recovery were obviously increased with the mixed solvents of methanol and acetic acid. The optimal operational conditions of the technology are that the ratio of agent to diesel is 1.0, the reaction time is 3 min, and reaction temperature is room temperature (from 20 to 30°C). The extraction rate of basic nitrogen was up to 90.8%. The refined oil recovery is about 93.5%. The processing has some characters such as simple equipment, low refining expenditure, easy to control, and no pollution. This new refining process can be applied in some small refineries.

Denitrogenation of Straight-run Diesel With Complexing Extraction

Effect of ZSM-5 acid modification on aromatization performance of methanol

Purpose – This paper aims to evaluate the inhibition efficiency of thiadiazole derivatives, such as 2,5-dimercapto-1,3,4-thiadiazole (DMTD), 5-methly-2-mercapto-1,3,4-thiadiazole (MMTD) and 2,5-dithiododecyl-1,3,4-thiadiazole (DDTD), in 50 mg/L hydrogen sulfide for silver strip. Design/methodology/approach – Evaluation was carried out by corrosion-inhibiting test, electrochemical measurement and surface analysis techniques. 3D surface profiler, atom force microscopy, scanning electron microscopy and energy-dispersive X-ray analysis were applied and finally confirmed the existence of the adsorbed film. Findings – The electrochemical measurement showed that the inhibition efficiency increases with increasing inhibitor concentration in 50 mg/L hydrogen sulfide solution, while the corrosion rate and the corrosion current decrease. Weight-gained measurements also indicated that inhibitor decreases the corrosion rate in the studied solution. The adsorption of DMTD and MMTD on the silver surface obeys Temkin’s a...

Anti-corrosion behavior of thiadiazole derivatives for silver strip in hydrogen sulfide solutions

Purpose




This paper aims to evaluate the inhibitive effect and adsorption behavior of 5-(ethylthio)-1H-tetrazole (EHT) and 5-(benzylthio)-1H-tetrazole (BHT) on copper in a sulfur-ethanol system.




Design Methodology Approach




Evaluation was carried out using electrochemical measurement and surface analysis techniques. Measurements of static friction coefficient by scanning electron microscopy and contact angle analysis were applied and finally confirmed the existence of the adsorbed film. The inhibitive mechanism of the two compounds was evaluated by means of quantitative calculation and molecular dynamics simulation. The friction coefficient of corrosion surface before and after adding corrosion inhibitor was determined through static friction coefficient measurements.




Findings




The electrochemical measurement indicated that the most effective concentration of two corrosion inhibitors was 70 mg L–1, while the inhibition efficiency of that was EHT > BHT. The friction coefficient data showed that the addition of corrosion inhibitor reduced the roughness of the corrosion surface. Adsorption behavior of two inhibitors followed the Langmuir’s adsorption isotherm and was attributed to mixed-type adsorption. The results of quantitative calculation and molecular dynamics simulation showed that tetrazole rings of the two inhibitors and its connected S atoms were adsorbed on Cu(111) surface in parallel.




Originality Value




The corrosion inhibition performance of two tetrazolium derivatives in a sulfur-ethanol system was studied by combining experiments with theory, which provided a theoretical basis for the future research.

Jianhua Qian

Papers

Preparation and tribological properties of stearic acid-modified hierarchical anatase TiO2 microcrystals

Denitrogenation of Straight-run Diesel With Complexing Extraction

Effect of ZSM-5 acid modification on aromatization performance of methanol

Anti-corrosion behavior of thiadiazole derivatives for silver strip in hydrogen sulfide solutions

Corrosion inhibition and friction-reduction property of tetrazole derivatives on copper