مجله فرآیند نو
پیاپی 56 (زمستان 1395)

Heavy crude oil and bitumen production is on average twice as capital and energy intensive as the production of conventional oil. Pipelines are the most convenient means of transporting crude oil from the producing field to the refinery. However, moving heavy crude oil and bitumen is extremely challenging because of their inability to flow freely. Without prior reduction in the heavy crude oil and bitumen viscosity, transportation via pipeline is difficult. This is because of the huge energy required to overcome the high pressure drop in the pipeline due to their high viscosity at reservoir conditions. In this study, different technologies to improve the flow properties of the heavy crude oil and bitumen through pipelines are reviewed and the advantages and disadvantages of each technology are highlighted with the view that the review will provide direction for development of novel technologies for bitumen and heavy oil transportation via pipelines.

An industrial bulk process for the continuous production of high-impact polystyrene (HIPS) included seven An industrial bulk process for the continuous production of high-impact polystyrene (HIPS) included seven continuous stirred-tank reactors (CSTR) is mathematically modeled and simulated. The results of steady-state model are validated with actual plant data. The good agreements between simulations results and industrial data have been observed.
Using dynamic simulation the time variation of monomer conversion, the molecular weight distributions, styrene concentration, initiator concentration, modifier concentration and inhibitor concentration and un-reacted butadiene repetitive units concentration investigated. The effects of various operating conditions such reactors temperatures on the dynamic properties of reactor output such measure monomer conversion, grafting efficiency, the number and weight-average molecular weights have been investigated. The results show that with increasing temperature, monomer conversion increases and averages molecular weights reduce.

In this research, MnOx catalysts supported on Multi/Single-walled carbon nanotubes and activated carbons were prepared by incipient wetness impregnation method and their low-temperature selective catalytic properties were studied. H2-TPR, XRD, TEM and ASAP were employed to probe the effect of carbonaceous supports and the nature of the oxidation state of the manganese appeared on catalyst surface. Based on the obtained results, it was concluded that 12wt% MnOx over single-walled nanotube had the highest activity. H2-TPR analyze of the catalyst supported on single-walled nanotubes revealed the presence of partially undecomposed Mn-nitrate species and formation of MnO2/Mn2O3 phases over the surface of the support. However, H2-TPR analyze of the catalyst supported on active carbon proved the dominant phase of manganese oxide is Mn3O4. So, in this way, the oxidation state of manganese seemed to be the key factor to get the best activity in comparison with surface area and active phase dispersion.

Biodiesel production in a membrane reactor at steady state condition was investigated numerically. Because of its advantages, transesterification method was used to produce of biodiesel. The reactor was assumed isothermal. Tube and sell side of reactor component mole balance equations were solved by Runge Kutta fourth order. The results showed that the material velocity inside the tube is more effective on reactor conversion than that inside the reactor shell. Conversion of triglyceride was 3.8 fold increased with 75% and 50% reduction in average velocity in tube and shell side, respectively. The lengths of less than 6 m for membrane reactor, optimized to produce high-purity product.

The aims of this research is to show importance and effectiveness of implementation HAZOP Study during project life – cycle of any plant and essential of attention to identifying all potential hazards by manager due to manage and control them. Hence, in this research included two main parts which one is assessing and another is improving of production rate. In the assessing section the researcher collected some technical and safety data and showing the effectiveness of the first HAZOP Study which implemented in 2006. In HAZOP Study review section, the researcher studied how to reduce production losses as well as to reduce accidents during work which observed 24 cases by making a team to review the first HAZOP Study. Also in this research circulated questionnaire to different levels of personnel in STPC. In continue, as per the survey results prioritizing all risks.

Air pollution is one of the most important environmental pollution which origins from using fossil fuels like gasoline or diesel fuel. Nowadays using fuels like biodiesel with less emissions, in comparison with diesel, has contributed to reducing emissions produced by combustion of diesel fuel. Although pollutants such as carbon monoxide (CO), unburned hydrocarbon (UHC) and soot resulting from combustion of biodiesel are significantly less in comparison with diesel fuel, the low torque and power and high level of nitrogen-oxygen compounds are of disadvantages of using biodiesel as an alternative for diesel fuel. Application of nano-additives in such fuels is one way to reduce the emissions and to enhance performance of motor parameters. Consequently, in this paper different types of these nano-catalysts were discussed.