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gas-purification
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Rule of thumb for gas permeation systems' calculations
, Article Petroleum and Coal ; Volume 57, Issue 4 , 2015 , Pages 360-365 ; 13377027 (ISSN) ; Mivechian, A ; Sharif University of Technology
Slovnaft VURUP a.s
2015
Abstract
In gas purification using polymeric membrane systems, different parameters affect on product specification. In these systems, pressure ratio, stage-cut, membrane selectivity and feed purity are important parameters which changing in these parameters results in a different product specification. Existence of a mathematical correlation between these parameters can be helpful and it gives a view that shows how can approach to products with desired specification. In present study, a correlation between effective parameters has been developed. This dimensionless mathematical model shows how product purity and recovery are influenced by membrane selectivity (DR; from 2 to 125) and feed purity in...
Review and Simulation Process of Deposition in Fluidize Bed(Focus on Heat Transfer)
, M.Sc. Thesis Sharif University of Technology ; Roosta Azad, Reza (Supervisor) ; Yaghmaei, Soheyla (Co-Advisor)
Abstract
This project related to gas purification according to difference in the deposition point in the fludized bed.The main reason for choosing fluidized bed is increasing overall heat transfer coefficient compare in to other heat exchangers. Separation process, by cooling the wall causes the self- deposition gas phase shifts to solid phase. Solid formed on the wall, act as an insulating layer and greatly reduces the heat transfer. To solve this problem, the fluidized bed system is offered because fluid particles in addition to remove the insulating layer, improving convection heat transfer coefficient . Laboratory tests show the feasibility of preventing the formation of insulating layer by...
Multi-objective optimization of a multi-layer PTSA for LNG production
, Article Journal of Natural Gas Science and Engineering ; Volume 49 , 2018 , Pages 435-446 ; 18755100 (ISSN) ; Farhadi, F ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In this work, a novel multi-layer pressure-temperature swing adsorption (PTSA) process was designed for efficient simultaneous water and mercaptans removal from natural gas (NG) to less than 0.1 ppmv and 3 ppmv in a mini liquefied NG unit. The proposed multi-layer PTSA consists of a three-layer fixed bed including activated alumina, molecular sieves 4A and 13X. To gain in-depth insights about the process, a descriptive model considering mass, energy and momentum balances, along with the kinetic and equilibrium equations was developed. After validating the model with the experimental and operational data from the literature, the total energy requirement and long-term operational requirements...
Examination of Activity of Three-Way Catalysts Toward CO and Hydrocarbon Emission Reduction from Tehran Gasoline Taxis
, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh (Supervisor) ; Hosseini, Vahid (Co-Supervisor)
Abstract
Air pollution is one of the main environmental problems in Iran's metropolises, especially in the city of Tehran. Taxis have a significant contribution to pollution due to the long distances they travel during the day. Due to the fact that the operation of automotive three-way catalysts is a function of their operating conditions, and considering the different fuel composition in Iran and the specific conditions of engine performance, exhaust gas composition can be different from similar cases abroad. A commercial three-way catalyst was tested to evaluate its performance under conditions relevant to the exhaust gas of Tehran's taxis fleet. In this study, CO and C3H6 were considered as the...
Grand canonical Monte Carlo and molecular dynamics simulations of the structural properties, diffusion and adsorption of hydrogen molecules through poly(benzimidazoles)/nanoparticle oxides composites
, Article International Journal of Hydrogen Energy ; Volume 43, Issue 5 , 2018 , Pages 2803-2816 ; 03603199 (ISSN) ; Dehghani, M ; Pazirofteh, M ; Asghari, M ; Mohammadi, A. H ; Shahsavari, D ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Comprehensive structural/molecular simulations have been undertaken to study the poly(benzimidazoles) (PBI) membrane combined with four different nano-oxide materials (ZnO, Al2O3, SiO2 and TiO2) for purification and production of hydrogen from natural gases. Composite membranes were built with different amounts of nano-oxide materials to investigate the influence of nano-oxide content on the PBI membrane performance. Several structural characterizations such as FFV, WAXD and also a thermal one (glass transition temperature) were done to study the structural properties of all simulated membrane cells. Moreover, MSD and adsorption isotherms tasks were used to estimate the diffusivity and...
High yield of CO and synchronous s recovery from the conversion of CO2 and H2S in natural gas based on a novel electrochemical reactor
, Article Environmental Science and Technology ; Volume 55, Issue 21 , 2021 , Pages 14854-14862 ; 0013936X (ISSN) ; Zhang, B ; Zhang, Y ; Zhou, C ; Wang, P ; Zha, L ; Li, J ; Simchi, A ; Zhou, B ; Sharif University of Technology
American Chemical Society
2021
Abstract
H2S and CO2 are the main impurities in raw natural gas, which needs to be purified before use. However, the comprehensive utilization of H2S and CO2 has been ignored. Herein, we proposed a fully resource-based method to convert toxic gas H2S and greenhouse gas CO2 synchronously into CO and elemental S by using a novel electrochemical reactor. The special designs include that, in the anodic chamber, H2S was oxidized rapidly to S based on the I−/I3− cyclic redox system to avoid anode passivation. On the other hand, in the cathodic chamber, CO2 was rapidly and selectively reduced to CO based on a porous carbon gas diffusion electrode (GDE) modified with polytetrafluoroethylene and cobalt...