Sharif Digital Repository

Dependence on fossil fuels as the main energy sources has led to serious energy crisis and environmental problems, i.e. fossil fuel depletion and pollutant emission. Compared with fossil fuel, biomass is a clean energy with zero CO2 emission, because CO2 is fixed by photosynthesis during biomass growth and released again during utilization. Due to its low energy density, direct use of biomass is not convenient. Thus, it is necessary to convert biomass to fuel gas, such as hydrogen, which can be used cleanly and highly efficiently. One of the promising hydrogen production approaches is conversion from biomass, which is abundant, clean and renewable. Alternative thermo-chemical and biological... 

A microbial fuel cell (MFC) is a bioreactor that utilizes chemical energy in the chemical bonds of organic compounds to electrical energy production through catalytic reactions of microorganisms under anaerobic conditions. In this study, the performance of a dual chamber, mediator-less anode, graphite electrodes MFC employing mixed consortia as anodic inoculums and using a combination of formalin and glucose as substrate was investigated. Different MFCs with different concentration of formalin and fixed concentration of glucose was operated to elucidate the difference in power generation and removal of formalin as an industrial pollutant under similar operating conditions [ambient pressure;... 

increasing energy demand and emission of environmental pollutant as a result of using fossil fuels and increase in waste generated due to human activities resulted in considering this source as a partial substitute for fossil resources in power application . Hence in this project biomass is considered as source of energy for heat and power application. Having low quality energy is the most important difficulty for application this resource as an energy carrier, so, gasification is applied to convert this source to gas with higher quality one. Produced gas in gasification enters to a micro turbine to meet thermal and electrical demand of the Sharif energy research institute. To investigate... 

Depletion of fossil fuels and their price increase, world is going to face critical energy challenges in the near future. Thereforefinding proper replacements for fossil fuels is inevitable. On the other hand, releasing of huge amount of wastewater into environment imposes serious nvironmental threats. Microalgae can be a potential alternative for biological wastewater treatment as well as fuel production. Microalgae grown in wastewater can eliminate remaining nitrogen and phosphorous. The gorwn biomass can be used for biofuel production afterward. Microalgae can also decrease the amount of greenhouse gas through the consumption of CO2 as energy sources. In this study, nutrient removal from... 

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... 

Reduced supplies of fossil fuels worldwide attention to the economic and energy-efficient processes for the production of fuel from renewable sources is diverted.Biomass has the potential shown because it has features such as frequency and is renewable. Because of the high solubility of hydrocarbons derived from biomass in large amounts of water and oxygen, the process is then performed on the aqueous phase is considered. Recent research for the production of alkanes by the deformation of the aqueous phase (Aqueous Phase Reforming) by Catalyst on hydrocarbons derived from biomass, such as glycerol, ethylene glycol, sorbitol, glucose, and etc. has been done. Here is our attempt to use the APR... 

The aqueous phase reforming (APR) of glycerol is an attractive yet challenging pathway to convert abundant biomass into value added hydrogen. Pt catalysts have received attention due to their ability to produce hydrogen-rich gas under APR conditions. In this work, the conversion of glycerol into hydrogen is demonstrated using Pt0.05CexZr0.95-xO2 (x=0, 0.29, 0.475, 0.66 and 0.95) solid solution catalysts and a series of M-doped Pt-MgO (M = Pd, Ir, Re, Ru, Rh and Cr) sheet-shaped nano-catalysts. Both characteristic (XRD, BET, H2-TPR, CO-chemisorption, TEM and XPS) and reactivity measurements were used to investigate the activity of the catalysts. Results indicated that reactivity depended on... 

Nowadays, one of the most basic human problem is how to manage energy resources for sustainable development and how to deal with problems caused by growing energy consumption. Various scenarios are being discussd that the most important of them can be considered research on finding alternative energy sources that are renewable and do not have common pollution. Thus, according to researches carried out until now, using sources such as wind, water, solar biomass, etc. have been proposed. However, due to problems in the development of each of these sources, biomass as the primary option has been introduced. because biomass has several subsidiaries, research shows microalgaes (as a subset) are... 

Consumption of oil and gas as energy carrier leads to irreversible environmental effects related to greenhouse gases emission. Hence, for the reduction in greenhouse gas emission, a shift to renewable resources for energy supply is recommended. However, in recent years, hydrogen has emerged as the most promising clean energy carrier for generating electrical power through fuel cells. Nevertheless, production of renewable hydrogen is the main barrier to the development of hydrogen as an energy carrier. Aqueous phase reforming of oxygenated hydrocarbon is developed by Dumesic for producing renewable hydrogen-rich gas with low CO. Since it is expected that, use of new technology such as the... 

Hybrid Solid Oxide Fuel Cell-Micro Gas Turbine systems(SOFC-MGT) present opportunities for improvement over conventional systems, including high efficiency, cogeneration, and the potential for low carbon emmisions. In order to advance toward commercialization, Hybrid systems need to model under design point and off-design situations that maintain safe and efficient operations, also exhibiting favorable exergetic and economic performance. The present work investigates the hybrid SOFC-MGT performance and effects of steam injection, humidity effect, and fuel change in the system. The 1-D model of SOFC stack has been developed in EES Code and then coupled with a microturbine’s components with... 

In biotechnology processes, in addition of culture media there is a solid phase which dispensed across the system.In most of bioprocesses, first operational unit for downstream treatment is the separation of this particles from fermentation liquor. In contrast with other categories like inorganic chemistry, solid particles in fermentation liquor (which the main part of it is biomass itself) have complicated physical & rheological properties. For example, all of biomass species are hydrophilic and sometimes form colloidal solutions.With this perspective, separation of solid phase from fermentation liquor is a hard challenge in this kind of processes.In this research, with regard of great... 

This thesis explores the co-benefits of hydrogen production from biomass sources as a sustainable energy solution to address environmental challenges in Tehran, Iran. Utilizing a comprehensive life cycle assessment framework, the study evaluates the environmental impacts of various biomass-to-hydrogen conversion technologies, including gasification, fermentation, supercritical water gasification, microbial electrolysis cells, anaerobic digestion, and pyrolysis. Data for some technologies were sourced from previous studies, while data for the gasification process were obtained through simulation software, considering chemical looping gasification. The ReCiPe2016 method for midpoint and...