Journal of Gas Technology
Volume:3 Issue: 1, Winter 2018

In this study, the solubility of acid gases of hydrogen sulfide and carbon dioxide in MDEA and MDEA/PZ aqueous solutions was evaluated by different thermodynamic packages. Comparison of modeling results with a series of laboratory and industrial data released from 1997 to 2010 indicates the high accuracy of ACID GAS thermodynamic package (Aspen HYSYS 8.3) to prediction of acid gases solubility in the mentioned solutions compared to the ELECNRTL thermodynamic package (Aspen plus V8.2), especially in the range of acid gases operational concentration in the gas refineries.

In order to conduct laboratory studies on composition and behavior of Claus-derived molten sulfur, the examined sulfur should contain dissolved H2S and H2Sx with a concentration of about 230-250ppmw. Here, by injecting hydrogen sulfide to sulfur, A method for synthesis of molten sulfur containing hydrogen sulfide and polysulfide as a proper sample for laboratory studies is developed . The product molten sulfur was prepared by injecting the pressurized hydrogen sulfide on the surface of solid sulfur followed by further heat treatments during the time. According to the Iodometric Back Titration (IBT) analysis, final molten sulfur contained 500-1100ppmw of soluble hydrogen sulfide and polysulfide components based on the initial gas pressure.

Spontaneous counter-current imbibition is one of the most important crude oil recovery processes in water-wet fractured reservoirs with low matrix permeability. This paper presents a numerical modeling of imbibition process when water is imbibed by capillarity and gravity forces in to an oil saturated vertical cube core to examine the effect of gravity force on spontaneous imbibition. In this modeling, we assumed that imbibition is a diffusion process. Finite difference implicit method was used to solve the spontaneous imbibition equations. Accuracy of the modeling is investigated with comparison of the modeling results and the experimental data.

Flow capacity of a gas transmission pipeline is usually affected by different parameters. In this study several determining factor are selected for sensitivity analysis of flow capacity prediction in IGAT-IV. These parameters include: pipeline parameters, gas parameters, system parameters, heat transfer parameters, compression parameters and compressor fuel consumption parameters. Detail calculation has been performed by developing a computer program by Microsoft Visual Basic. Moreover, a computer program for generating the compressor performance curve has been written by MATLAB. This curve has been used to design and optimize the compressor stations. From the present investigation, it has concluded that AGA Fully Turbulent, Colebrook-White and Weymouth equations have the best prediction of flow rate in gas transmission pipelines. 87.85 % flow changes due to 1% isentropic exponent change, which has a very large effect on the flow capacity. 10% to 30% flow changes due to 1% suction compressibility factor and discharge compressibility factor change. They have large effect on the flow capacity. 1% to 10% flow changes due to 1% compressor horsepower, compressor suction and discharge temperature and adiabatic efficiency change. They have medium effect on the flow capacity. The other parameters have not significant effect on the flow capacity.

In this work computational fluid dynamics is used to describe the fluid flow across a randomly packed absorption tower. The CFD simulation method is employed on a packed tower that is packed with 1cm Raschig rings. Tower is 175cm in height. Air flow rate range was 1.5 to 5 m/s. The measured pressure drops were in 1.5 to 12 Pascal per height of tower in meter. The Klerk’s approach is examined to define the influence of confining walls on pressure drop in packed areas. It is concluded that CFD model that uses the Klerk’s definition of radial porosity distribution is a successful way for pressure drop prediction in packed beds. Model prediction of dry pressure drop is about 4% lower than the experimental measurements. Ergun’s pressure drop prediction is compared with that of Reichelt’s using averaged and distributed porosity profiles. In both methods Ergun’s approach in comparison with Reichelt’s approach has %6 lesser error in dry pressure drop prediction.

In this study, PES/Pebax composite membranes were prepared by coating the porous PES support layers by Pebax-1657. Film casting and pouring methods were used for coating Pebax layer. The effects of coating technique and conditions including coating solution concentration and curing temperature on CO2 and CH4 gas permeabilities of prepared composite membranes were investigated. SEM images were used to investigate the structure of the prepared membranes. Pure CH4 and CO2 gases were used to investigate the gas permeation properties of the prepared membranes at different trans-membrane pressures (1-11 bar) and feed temperatures (25-55°C). The obtained data showed that the prepared PES supports did not provide any CO2/CH4 selectivity. The results also showed the CO2/CH4 selectivity for the membrane prepared via pouring technique was higher than that of the film casting procedure due to the defect-free Pebax layer formation. CO2 and CH4 permeance increased as the feed temperature increased from 25 to 55°C. The results also showed that CO2 permeance increased from 6.8 to 10.1GPU with an increase in feed pressure from 2 to 12barg, while CH4 permeance remained almost constant and CO2/CH4 selectivity increased from 27 to 42.