مجله فرآیند نو
پیاپی 81 (بهار 1402)

In this investigation, the liquid-liquid extraction process of aromatics from SAE 30 lube oil by furfural using the calculated physical properties (density, specific gravity, and refractive index) of pseudo-component (paraffinic, naphthenic, and aromatic) and the NRTL parameters has been studied. The extraction temperature (328, 338, and 348 °K) and the solvent to feed volume ratios (1, 4, and 7) were examined in order to determine their optimum values. The modeling results demonstrated that by increasing the solvent to feed ratio and the extraction temperature, the weight percentage of furfural and the yield of raffinate phase decrease. The accuracy of the model was checked by simulating single-stage extractions using ASPEN HYSYS. Good agreement was found between predicted and experimental values of yield, furfural content, composition, and physical properties for raffinates and extracts. The maximum errors between calculated values and industrial values of pseudo-component contents are less than 2%.

Mixing or dispersing operation is an important section in chemical processes. Because of several advantages like: low capital cost, low operating cost, low maintenance cost and low required space; static mixers are applied in many industries. In crude oil desalting process, static mixers for dispersion of the dilution water in crude oil is proposed by this study; which conventionally a mixing valve is used. Type of the static mixer in the applied operating conditions effects on the properties and the stability of the resulted emulsion. In a pilot scale setup, three types of SMV, HMS and LPD static mixers have been investigated; for different conditions of water fraction (2-15%) and crude oil flow rate (86-144 l/h). The experimental results show that SMV outcomes the most stable emulsion which is not appropriate for desalting process. Against, LPD is the optimal choice for the said application, regarding to the emulsion properties.

One of the most important pollutants that cause air pollution in cities is volatile organic compounds that cause many complications in people. Gasoline pumps as well as cars are among the most important sources that cause the accumulation of these pollutants, and due to the increasing number of cars, gasoline pumps have become a dangerous place that should be taken into consideration. Since air pollution is a very complex process that depends on many factors, it is very difficult and expensive to predict such data, which have nonlinear dynamics. In this research, by collecting experimental data from three gas stations in Zanjan and identifying the influencing parameters, modeling has been done using artificial neural network. That, two multilayer perceptron models and radial basis function were investigated. In the statistical part of this research, the correlation coefficient and the sum of squared errors were used as necessary criteria to measure the accuracy of the two mentioned models. The results and analysis conducted in this study showed that the pollution resulting from the consumption of gasoline includes two stages, one at the time of refueling and the other after refueling. Also, in the summer, the concentration of volatile organic compounds is higher than in the winter, and this amount of pollution is observed more in the morning and evening.

Liquefied petroleum gas (LPG) refers to the hydrocarbon gases propane, butane or their combination. Liquid gas is often used for heating purposes and vehicle fuel. In refineries, the hydrocarbon flow of propane, butane and pentane contains impurities such as methyl mercaptan, ethyl mercaptan and other mercaptans. In this research, the simulation of mercaptanization unit of Abadan refinery has been done. First, the unit was simulated in the ProMax software and after the validation of the simulation, the effect of process variables such as the caustic flow rate, caustic concentration, sour feed flow rate and washing column pressure on the concentration of mercaptan in product has been investigated. The concentration of mercaptans in the output product has been discussed. The results of the simulation show that the total calculation error is less than 10%, which indicates the accuracy of the simulation in steady state. Based on the simulation results, with the increase of caustic flow rate, concentration of caustic solvent and washing column pressure, the amount of produced product (ethyl mercaptan and methyl mercaptan) decreases. Only by increasing the flow rate of sour feed, the amount of produced product will increase.

Due to the problems associated with fossil fuels, much attention has been paid to hydrogen as a renewable energy source. The development of membrane processes and membrane reactor technologies has led to a greater focus on the possibility of producing high-purity hydrogen via reformed processes. Based on research conducted on hydrogen production using fluidized bed membrane reactors and fixed bed membrane reactors, it is evident that fluidized bed membrane reactors require a larger membrane surface area. Therefore, this article reviews and analyzes the research conducted on the development of fluidized bed membrane reactors for hydrogen production. The results of the steam methane reforming process in a fluidized bed membrane reactor show that a hydrogen product purity level of up to 99.994% is achievable. Therefore, hydrogen production using fluidized bed membrane reactor technology, which has lower costs and higher efficiency, can be a suitable substitute for fossil fuels.

With the progress of science and technology, new processes were created in combustion, the most important goal of which was to optimize fuel consumption, increase efficiency, and specifically reduce the amounts of gaseous pollutants (such as nitrogen oxides and carbon monoxide). One of these new technologies is flameless combustion, which is based on the preheating of fuel and air and the dilution of oxygen in the air with the recirculation of combustion gases to create a proper mixing of the reactants. In the present study, the flameless combustion of methane gas is simulated in a laboratory combustion chamber. Its results are compared in two modes of using DRM22 (as a reduced mechanism) and GRI3.0 (as a complete mechanism). The results show that the mentioned mechanisms are able to calculate the distribution of temperature and chemical species with an error of 1.66% and 4.7% respectively, and with good accuracy compared to the experimental results. In the case of NOX, despite the 26% difference between the two mechanisms, the GRI3.0 mechanism calculated its concentration slightly more than expected. On average, the DRM22 mechanism is closer to the experimental results and has less calculation time.