Journal of Oil, Gas and Petrochemical Technology
سال پنجم شماره 1 (Summer and Autumn 2018)

This paper presents the feasibility of the removal of asphaltenes from aqueous solutions by using low- cost natural adsorbents such as light expanded clay aggregate (LECA), perlite and bentonite. The structure of adsorbents was characterized by XRD, FTIR, and SEM before and after the adsorption of asphaltenes. The effect of the adsorbent type, initial asphaltene concentration, particle size of the adsorbent and temperature on the adsorption capacity was investigated. The results showed that at the initial asphaltene concentration of 125 mg L-1, contact time of 24 h, temperature of 50°C and adsorbent dosage of 1 g, the removal of asphaltenes onto LECA, perlite and bentonite was 53.59, 93.01 and 99.77%, respectively. Also Langmuir and Freundlich models were applied to describe the experimental data. The results indicated a good fit by Langmuir isotherm. Thermodynamic parameters such as ∆H, ∆S and ∆G were also calculated. It was revealed that the adsorption was spontaneous and of exothermic nature, which was evident by decreasing the randomness of the dye at the solid and liquid interfaces. The characteristic results and dimensionless separation factor (RL) showed that perlite and bentonite can be employed as an alternative to commercial adsorbents for the removal of asphaltenes from the aqueous solution and oil.

Nowadays, oily wastewater is increasing along with the growth of various industries. So, wastewater treatment is necessary in order to protect the environment. In this study, a mullite ceramic membrane was prepared. Then, oily wastewater treatment with 200 mg L-1 concentration was investigated by the response surface methodology based on Box-Behnken design (BBD) using Design-Expert 7.0.0 software. Membrane characterization was done using XRD, SEM, and porosity analysis. Based on XRD results, the major phase of the membrane was mullite. Furthermore, according to SEM image and porosity analysis, the pore size and the membrane porosity were 1.7 μm, 47 %, respectively. The experimental parameters were temperature (T, 20 - 40 ºC), pressure (P, 2 - 4 bar) and cross flow velocity (CFV, 0.5-1.5 m s-1). In addition, the flux was considered as the response. The optimum conditions for achieving the maximum response were 39.62 ºC of T, 3.92 bar of P, and 1.34 m s-1 of CFV. The maximum permeate flux was 42.93 L m-2 h-1. The rejection was investigated under different pressure from 2 to 4 bars. The maximum rejection was observed at 2 bars with the amount of 97.4 %.

In this study, tomato seed oil was used to produce Biodiesel fuel. To reduce the percentage of free fatty acids, the oil was reacted at a temperature of 40, 50, and 60°C with a mixture of sulphuric acid and the industrial methanol with different molar ratios of oil. The best conversion efficiency was achieved at 60°C and a molar ratio of 1:9. In the transesterification step, biodiesel was produced using a mixture of potassium hydroxide reactivity. Then, functional characteristics and pollutant gases of ordinary diesel fuel and mixtures of biodiesel at different speeds and loads were measured and compared. The tests were carried out in a 9-kV direct injection (DI) diesel engine. The results of analysis of variance by SPSS software showed that there was a significant difference in the level of R< 0.01 between the production of pollutants such as NOx, CO, HC, and other fume gases like CO2 and O2 at different speeds and loads. Duncan’s multiple range test results also showed that the lowest emissions were generated from the B20 blend. An Artificial Neural Network (ANN) model which was used to predict the emission of the engine showed an excellent conformity with R-values of 0.99 for both the training and test data.

Methyl propionate, also known as methyl propanoate, is a clear colourless liquid with a characteristic odour (fruity smell and taste). In this study, the formation of methyl propionate through the esterification of propionic acid and methanol was investigated in the reactive distillation system using a conventional (CBD), single feed (SF-SBD), and double feed semi-batch distillation (DF-SBD) columns for the first time. The performances measure of these distillation systems were evaluated in terms of minimum batch time for a given separation task. The optimization results clearly showed that the DF-SBD system is a more attractive operation in terms of reaction conversion, and maximum achievable purity as compared to the SF-SBD, and CBD processes.

Membrane separation is known as an efficient technique for the oily wastewater treatment. Therefore, in the present study, sulfonated poly (ether ether ketone) (SPEEK) was introduced into the polysulfone (PSF) solution in order to enhance the hydrophilicity and the membrane structure for the oil–water separation. The hollow fiber membranes were fabricated via a phase-inversion process. The membranes were characterized by a N2 permeation test, overall porosity, water contact angle, pure water flux and scanning electron microscopy (SEM) analysis. The blend PSF-SPEEK membrane presented an open finger-like morphology with a thicker outer skin layer and smaller pore sizes. The blend membrane showed overall porosity of 78.8% due to the open structure. The outer surface water contact angle of the blend membrane decreased approximately 8º due to the hydrophilic nature of SPEEK. The blend membrane showed N2 permeance of 134 GPU and mean pore size of 22 nm. Improved pure water flux of 9.3 L/m2 h at 400 kPa and the small resistance of 0.483 m2 h bar/L for the blend membrane were related to the higher hydrophilicity and the open structure. The blend membrane showed the oil rejection of over 98% and the stable water flux of 6.5 L/m2 h due to the improved structure.

In oredr to reduce costs and save time for the membrane manufacturing process, it is necessary to improve the quality of membranes by modeling usage. In this study, Flory Huggins model was used to predict quaternary-system containing polyether sulfone, N-Methyl-2-pyrrolidone, water and used alkanes as an additive. Due to the solubility parameters and molar alkane volumes, the interaction parameters changed which influenced the membrane morphology. In the meantime, modeling showed that hexane had no effect on the immiscibility gap, and the decane had a greater effect compared to hexane. But the tetradecane, due to the increased interactions, could greatly increase the immiscibility gap and increase the thermodynamic instability. Hence, those instabilities can become subjected to faster membrane entelechy, construct a pores skin layer, and change the membrane morphology. Whatever the immiscibility gap rise, the proportion of pores in the skin layer will increase and vice versa.