Journal of Oil, Gas and Petrochemical Technology
سال یکم شماره 1 (Winter and Spring 2014)

Polybutadiene nanoparticles were synthesized via batch emulsion polymerization of butadiene in the presence of potassium persulfate, disproportionate rosinate potassium cation and t-dodecyl mercaptane as initiator, emulsifier and chain transfer agent, respectively. Polymerization reaction was performed at different temperatures (60, 70 and 80 °C). Conversion was measured at the various time intervals by gravimetry method. Particle size and its distribution of the polybutadiene latex were measured by dynamic light scattering (DLS) and SEM analyses. Polymer microstructure was investigated by FT-IR spectroscopy. By increasing the polymerization temperature, average diameter of polybutadiene nanoparticles decreased from 104 nm (at final conversion of 80.6%) at 60 °C to 88.7 nm (at final conversion of 98.0%) at 80 °C. Dominant microstructure, i.e. 1,4-trans isomer content, in the synthesized polymers was calculated to be about 60%. Results showed that by increasing the reaction temperature, particles’ size decreases while number of the polymer particles and polymerization rate increase.

The organic deposition particularly asphaltenes has many detrimental effects on the oil industries, such as plugging in pipelines, wellbore and facilities and subsequently, considerable reduction in well productivity.Asphaltenes are the most polar fractions, which they have been dispersed as colloidal clusters in crude oil. The accumulation of these clusters lead to the flocculation of colloids, and accordingly, formation of precipitation. Adding inhibitor is one of the ways to prevent clustering of asphaltene precipitation in crude oil. In this study, the effect of inhibitors to prevent asphaltene precipitation was investigated by viscometric method. At first, the different concentrations (1000 ppm, 2000 ppm, 10000 ppm and 20000 ppm) of some aromatic, anionic and nonionic inhibitors were prepared in a dead crude oil sample, and then the inhibition strength of samples was measured. The results showed that inhibition strength of inhibitors in low to moderate (1000 ppm – 10000 ppm) concentrations has a regular pattern, and it is associated with functional groups in chemical structure of inhibitors.

Iran’s vast common natural gas resources and the necessity to extract and export it as Liquefied Natural Gas (LNG) to distances more than 3000Km opens a lucrative field for researchers to optimize LNG cycles. In this article heat integration in cryogenic cycles by determining interacycle partition temperature and optimizing refrigeration features like Subcooler, Presaturator, aftercooler, reboiler, superheater and economizer is investigated to reduce compressor shaftwork. Better conceptual understanding of design improvement is illustrated on Composite Curve (CC) and Exergetic Grand Composite Curves (EGCC) of Pinch-Exergy analysis diagrams. A program (LNG-Pro) is developed by integrating Visual Basic Application, Refprop(Reference Fluid Thermodynamic and Transport Properties) and Excel MINLP Solver to automate the methodology on an LNG plant with the capacity equal to a south pars gas field phase. Shaftwork is step by step reduced from 1479.36Kj/Kg to 1255.5Kj/Kg and 1158.8Kj/Kg which is 2.46% less than required energy for liquefaction in LNG industry.

The removal of disulfide oil (DSO) from contaminated soil was studied by the bioremediation method and the influence of electrokinetic on the bioremediation process was investigated. The bacillus subtilis strain was used in the bioremediation process. The effects of humidity, time and DSO concentration in soil was studied. The experimental results for the bioremediation of DSO show, the removal percent of DSO reach to 67% at 30oC and 26% humidity after six days. For the electrokinetic bioremediation (EK – bioremediation) experiments, the optimal current density was determined and several experiments at different times were performed. The concentration of DSO and the humidity was 20 L/ g. soil and 26% respectively. The DSO removal percent was reached to 61% after two days. The maximum DSO concentration in soil was 50 L/ g. soil. The comparison of the EK – bioremediation with the bioremediation method shows, the EK – bioremediation reduce the biodegradation time for DSO significantly.

This study has been investigated, the effects of three different polar polyacrylamides (anionic, cationic, and nonionic) on asphaltene deposition in porous media. All experiments were carried out in various dead oil flow rates (0.2, 0.1 and 0.02 cc/min) and different polymer concentrations (500, 2500, 4000 ppm). The results indicated that asphaltene precipitation was affected by the presence of polar additives such as charged polyacrylamide. In general, anionic polyacrylamide increased the asphaltene deposition. The amount of deposition is proportional directly to the increasing concentration of anionic polyacrylamide. Anionic polyacrylamide with the concentrations of 2500 and 4000ppm behaved as a promoter while the hydrophilic property of nonionic polyacrylamide acts as an inhibitor of the precipitation. Stabilization of asphaltene deposition was disturbed in the presence of cationic polyacrylamide. Moreover, the electrostatic and acid-base mechanisms had showed a retarding effect on it. The flow rate is another parameter, which is taken into account besides other factors.

Non-Fourier heat transfer analysis of functionally graded (FG) spherical shells subjected to the radiative-convective boundary conditions at their inner and outer surfaces are presented. It is assumed that the material properties have continuous variations along the thickness direction. The incremental differential quadrature method (IDQM) as an accurate and computationally efficient numerical tool is adopted to discretize the governing differential equations in both the spatial and temporal domain. The fast rate of convergence behavior and accuracy of the method is investigated through different examples and also, the results are compared with those available in the open literature wherever possible. Comparison studies between the results of IDQM and Runge-Kutta method (RKM) are also performed to establish the superior computational efficiency of the IDQM with respect to RKM. After validating the present formulation and method of solution, the influences of different parameters on the temperature time history and temperature distribution of the FG spherical shells are investigated. It is shown that the radiation boundary conditions decrease the period of oscillation of temperature time history. Also, it is observed that by increasing the non-Fourier time constant, the non-dimensional temperature oscillatory behavior increases. On the other hand, the present study reveals that the IDQM, as an accurate and practically efficient method, can be used for the analysis of different problems in the fields of the oil and petrochemical engineering in the future.