Sharif Digital Repository

Synthesis gas (H2, CO) is widely used in chemical and petrochemical industries, utilized for methanol and ammonia production. Hydrogen is the main component of syngas which is considered as an appropriate alternative for fossil fuels. Catalytic steam reforming is one of the most common and economical pathway for syngas production. Light hydrocarbons such as propane which can easily be transported, stored and distributed, is a promising feed candidate for steam reforming. Catalyst deactivation along with low stability resulting from carbon formation and sintering is one of the main crucial problems in this process, leading to much research on the preparation of stable and coke resistant... 

Iran with the second largest gas reserves in the world makes the importance of Kish Island more vital. Kish gas field, with a capacity of 67 trillion cubic meters gas, is one of the main hubs of Iran gas production. One of the uses of natural gas is to produce petrochemical goods such as Methanol. In this thesis the focus is on economical evaluation of producing Methanol for amount of 5,000 tons per day from Kish gas field. As a result, the required feed has been estimated about 150 million cubic feet per day and the net capital investment calculated to be 941 million US dollars. The initial estimate of Direct Permanent Investment (DPI) was calculated to be $590.8 million. Having considered... 

The main purpose of this project is to achieve better design by using exergy analysis. First steam methane reforming process of Tehran refinery is simulated using ASPEN HYSYS. Reformer and high temperature and low temperature shift reactors are simulated using trusted kinetics from literatures and results are compared with plant data and، and there was a good agreement between simulation and plant data. A MATLAB program is written to calculate stream exergies and equipment exergy destruction using AUTOMATION. Streamlined life cycle assessment is done using sustainably metrics، and environmental impacts are evaluated. The main environmental impact was global warming. After exergy destruction... 

Synthesis gas is a gaseous mixture which mainly consists of carbon monoxide and hydrogen. Different methods are used to produce synthesis gas but the most important method is auto thermal reforming. This method is based upon catalytic reactions. Steam, oxygen and natural gas are the influents to the reactor and synthesis gas will be the effluent. Ni catalysts on alpha-alumina as the support media are usually used in this process. These catalysts are highly heat resistant and insure great qualifications for reactions. This thesis tries to find best solutions of synthesis gas production suitable for feeding to a methanol production unit. There are four main reactions. Three of which are highly... 

One of the processes for energy carriers creating from biomass is Gasification process. The main products of this process are hydrogen and carbon monoxide. Output of this process has an average calorific value and sensible heat. Using sensible heat for preheating inlet air is one the ways for enhancement gasification processes. In this study gasification process is modeled as zone modeling. The humidity, pressure and air preheating effects on output gas composition and system’s layout were investigated. In the first and second scenario comparing the shifting of gas blower from downstream to upstream of gasification reactor is studied. It is showed the average temperature and number of... 

According to global improving consumption of distillate products, like gasoline and diesel, reduction in light petroleum production and growth in exploring and extraction of heavy and sour petroleum, changing in refining structure of worldwide oil refineries is necessary and it is crucial to apply special processes for refining, conversion and cleaning of these heavy and extra-heavy petroleum. Gasification of these fuels, i.e. partial thermal oxidation of feed in the presence of gasifying agent (air, oxygen, steam or mixture of them) in the gasifier, is one of the new ways to convert heavy fuel oil to synthetic gas (syngas), that this gas can be used widely in downstream processes. Here,... 

The main objective of the present work is to achieve green design of a methanol plant by using life cycle process design (LCPD) and multi-objective optimization. As a starting point, simulation of Lurgi’s combined reforming process as a conventional reference methanol case (RMC) was performed in order to obtain its operational and kinetic parameters as well as its environmental impacts. The environmental concerns were calculated using one of the modern environmental impact assessment methods, i.e. life cycle assessment (LCA). To perform life cycle assessment of RMC, methanol production plant as well as its auxiliary units should be considered. The auxiliary units in the RMC include cryogenic... 

In view of environmental problems and the limited energy supply, synthesis of new liquid fuel from coal or natural gas is becoming a hot research in recent years. Dimethyl ether (DME) is one of the most promising alternates of such synthetic fuels. In this project the kinetics of direct DME synthesis from syngas (H2 and CO) over the new bifunctional catalyst has been investigated in slurry reactor system. A new mechanism and rate law expression were established. The kinetic model has been fitted the experimental data, which has been obtained by other researchers. The new bifunctional catalyst was composed of Cu/ZnO/ZrO2 and Al-modified H-Mordenite zeolite. The calculated apparent...