Sharif Digital Repository

Based on International Energy Agency studies, achievement of 450 ppm CO2-equivalent emission target in global emission means that the CO2 emissions in 2050 must be reduced to %50 of 2005 level, and this implies that a portfolio of emission reduction policies and strategies need to be exploited through current century. At the present time, Carbon Capture and Storage (CCS) Technology is a dominant strategy among all the long-term carbon abatement strategies in many countries. Nevertheless, its potential as a climate mitigating option will be proved, only if it is implemented in the countries which are developing at a great pace and taking advantage of fossil fuels in order to afford their... 

Over the past few decades, industrial development has caused a dramatic increment in greenhouse gas (GHG) emissions, as a leading cause of climate change. Modifying the industrial plants' environmental performance is the main pillar of improving efficiency that can reduce the waste of resources and make achieving lower-cost global emission reduction targets of the Kyoto protocol's clean development mechanism (CDM) possible. Considering the essentiality of knowledge-based research in increasing the awareness of policymakers by providing better access to accurate and reliable information, an analytical survey on efficiency in oil, gas, and petrochemical industries has been conducted by... 

Improving oil recovery and decreasing greenhouse gas emissions are two important attractive features of CO2-enriched water injection into oil reservoirs. Regarding these unique features, the main objective of this study was concentrated to evaluate the swelling behavior of crude oil as a fundamental mechanism of carbonated water (CW) flooding. To achieve these goals, the swelling and Bond number of light and heavy crude oils (namely LCO and HCO, respectively) are measured and compared to each other. The results obtained from the measured swelling factors of crude oil/CW show some complicated behaviors. That is, as temperature increases the swelling factor decreases at low pressure... 

Passenger cars (PCs) not only are a major contributor to greenhouse gas (GHG) emissions in Iran but also pose severe energy security challenges due to their dependence on gasoline. This study aimed to understand the future trends of the gasoline demand and GHG emissions from PCs in Iran and assess the effectiveness of mitigation policies. The data were collected from multiple sources and used to develop the survival rate function of PCs. The study used back-calculation to compensate for the short period of stock data availability. The use intensity of PCs was estimated based on the gasoline consumption statistics. Econometric models were developed to project the future PC stock and use... 

The monolithic catalytic converter still is the main pollution control device for modern vehicles in order to reach the ever-increasing legislative demands for low emission standards. The catalytic converters require a large expansion from the exhaust pipe to the front face of the monolith. Unfortunately, packaging constraints often do not permit the use of long diffusers. Hence, flow separation within the diffuser leads to a non-uniform flow distribution across the monolith. A uniform flow distribution at the inlet monolith face is favorable for the conversion efficiency as well as the durability of the catalytic converter. Therefore the main problem is to optimize the flow distribution at... 

In this paper we develop a stochastic programming approach to solve a multi-period multi-product multi-site aggregate production planning problem in a green supply chain for a medium-term planning horizon under the assumption of demand uncertainty. The proposed model has the following features: (i) the majority of supply chain cost parameters are considered; (ii) quantity discounts to encourage the producer to order more from the suppliers in one period, instead of splitting the order into periodical small quantities, are considered; (iii) the interrelationship between lead time and transportation cost is considered, as well as that between lead time and greenhouse gas emission level; (iv)... 

The biological oxidation of ferrous ion by iron-oxidizing bacteria is potentially a useful industrial process for removal of H2S from industrial gases, desulphurization of coal, removal of sulfur dioxide from flue gas, treatment of acid mine drainage and regeneration of an oxidant agent in hydrometallurgical leaching operations. The main purpose of this study was to find optimum values of the process parameters on the ferrous biooxidation rate by immobilization of a native Sulfobacillus species on the surface of low density polyethylene (LDPE) particles in a packed-bed bioreactor using Taguchi method. Five control factors, including temperature, initial pH of feed solution, dilution rate,... 

An experimental study of pollutant emissions of a SI gas engine with CNG fuel has been done. In this work the role of various parameters such as air-fuel ratio, the shape of combustion chamber and spark timing on pollutant emissions of the engine have been investigated. The effect of three different combustion chambers with various compression ratios was studied and it was found that combustion chamber shape has a vital effect on exhaust emissions. Copyright © 2005 SAE International  

This study aims to construct a quantitative framework to assess biological production of hydrogen from agricultural residues in a country or region. The presented model is able to determine proper crops for biohydrogen production, its possible applications and use as well as environmental aspects. A multiplicative decomposition method was designed to forecast future production and Monte Carlo simulation was employed in the model to evaluate the risk of estimations. From 2013 to 2050, the hydrogen production capacity could increase from 53.59 to 164.41 kilotonnes (kt) in Iran. The highest contribution to biohydrogen production (52.1% in 2013 and 73.3% in 2050) belongs to cereal crops... 

Besides increasing the installation of distributed generation plants, investigation on multi-carrier energy systems leads recent studies to focus on several aspects of Smart Energy Hub (S. E. Hub) systems. An S. E. Hub incorporates several modules which calculation of optimal size and operation of each have already attracted a great deal of research. Uncertainty in the modeling of these modules is an imperative factor that was not paid attention in S. E. Hub models properly. To build up a more precise framework for S. E. Hubs, here we present a stochastic model for real time electricity and natural-gas prices and electricity demands. In this paper, an S. E. Hub operates in order to minimize... 

Higher than a standard level, the humidity provides a suitable environment for the pathogenic microorganisms to grow and increases energy consumption for cooling, increasing greenhouse gas emissions. Desiccant air-conditioning (DAC) is an effective method to reduce humidity and energy simultaneously. Conventional desiccants are not suitable for use as a desiccant in building air conditioners, mainly because of high regeneration temperature and other issues such as limited equilibrium capacity and hydrothermal and cyclic instability. Metal-organic frameworks (MOFs) are a novel class of porous crystalline materials without the disadvantages of traditional desiccants. They benefit from a huge... 

Three-dimensional thermo-hydrodynamic analysis of gas turbine combustion chambers is of great importance in the power generation industry to achieve higher efficiency and reduced emissions. However, it is prohibitive to use a comprehensive full-detailed mechanism in their simulation algorithms because of the huge CPU time and memory space requirements. Many reduction approaches are available in the literature to remedy this problem. Here a new approach is presented to reduce large detailed or skeletal mechanisms of oxidation of hydrocarbon fuels to a low-cost skeletal mechanism. The method involves an integrated procedure including a Sensitivity Analysis (SA) and a procedure of Gradual... 

As part of its Paris Agreement commitment, Iran pledged to decrease 4 % of its carbon dioxide (CO2) emissions from 2020 to 2030. About 29% of total emission in Iran belongs to electricity supply while energy consumption in other sectors (transport, household, and industry) have a lower share in CO2 emission. The main concern here is finding the optimal mix of power plants in the electricity supply system that should be deployed to meet Iran’s mentioned respective targets and considering simultaneously interests of consumers and producers in this energy system. So, we developed a non-linear mathematical programming model for Iran’s electricity system to address this concern with changing... 

Biofuels are important alternative fuel in recent years. In this work, the bioethanol supply chain planning is performed by BioEnergy Supply Model to optimally find the best pathways using economic and environmental objective functions in Iran. Then, different sustainability criteria focusing on environmental, economic, and social concerns are assessed for possible routes of the bioethanol production from available resources. Although agriculture residues and wastes, decrease the greenhouse gas emissions but municipal solid wastes are more economic and require less water. The agricultural wastes and residues improve the sustainability. Then, criteria focusing on environmental, economic, and... 

Many highly populated cities are still struggling to reach clean air targets, while the zero greenhouse gas emission objectives may accelerate the path toward healthy air for all. Still, there is a fine line between intensive electrification's impact on greenhouse gas emissions and criteria air contaminants depending on the source of the electricity. In this study, the previous version of the emission inventory for Tehran was evaluated and re-calculated in a detailed bottom-up approach to provide the most updated data on the contribution of stationary sources derived by power plants vs. mobile sources. The objectives were to update the emission inventory for improved policymaking, study the... 

Emission characteristics of pure natural gas is fairly known, however more experimental investigation of natural gas combustion is necessary. In this research, emission and performance of a turbocharged natural gas SI engine are investigated experimentally at WOT and lean burn conditions. A computer code is also developed in MATLAB environment for predicting engine performance and NO emission and the results are validated with experimental data. Thermal boundary layer, as a novel approach, is considered in the simulation and a better agreement of predicted mass fraction burned was achieved at end part of combustion process when compared with experimental results. Experimental results have... 

Carbon dioxide miscible flooding has become a popular method for Enhanced Oil Recovery (EOR) because it not only efficiently enhances oil recovery but also considerably reduces green house gas emissions. However, it can significantly cause asphaltene deposition, which leads to serious production problems such as wettability alteration, plugging of the reservoir formation, blocking the transportation pipelines, etc. It is crucial to investigate the effects of different factors on asphaltene deposition. A novel experimental setup was prepared to employ a high-pressure visual cell for investigation of asphaltene deposition on a model rock under typical reservoir conditions. The evolution of... 

Energy hubs that incorporate a variety of energy generation and energy transformation technologies can be used to provide the energy storage needed to enable the efficient operation of a ‘smart energy network’. When these hubs are combined as a network and allowed to exchange energy, they create efficiency advantages in both financial and environmental performance. Further, the interconnectedness of the energy network design provides an added layer of reliability. In this paper, a complex network of energy hubs is modeled and optimized under different scenarios to examine both the financial viability and potential reduction of greenhouse gas emissions. Two case studies consisting of two and... 

Abstract Miscible carbon dioxide (CO2) flooding has become the most commonly and favorable approach in Enhanced Oil Recovery (EOR) because of its high oil reservoir sweep efficiency and contribution to the reduction of greenhouse gas emissions. Despite this, it can significantly favor the asphaltene deposition, which leads to the wettability reversal and formation damage. A novel experimental setup was utilized to study asphaltene deposition on the model rock at reservoir condition. The evolution of asphaltene deposition was monitored by a microscope; then analyzed by image processing software to check the amount of deposited asphaltene and its size distribution at different...