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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 46673 (46)
- University: Sharif University Technology
- Department: Energy Engineering
- Advisor(s): Roshandel, Ramin; Rashtchian, Davood
- Abstract:
- 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 moles of the input to the output of the blower reduced approximately near 54%. The side benefits, also it can be used for producing a positive pressure in the system for ensuring the lack of air infiltration, reducing the risk of explosion, to supply downstream pressure of the entire system, to prevent entering tar and suspension particles into the blower system. The third scenario have been proposed by the fact that a high-temperature output gas temperature is capable for producing affordable energy. Because the reaction of shifting carbon is exothermic, the reaction was done in the reverse order partially and increases carbon monoxide and decreases hydrogen. Preheating the incoming air increases the air outlet temperature at a constant rate. To remain constant outlet temperature due to technical limitations, the temperature was kept constant at 1150 ° K and the air ratio changed from 0.3 to about 0.24. This reduces the equipment size and energy consumption as well. In the fourth scenario, increased pressure is investigated. This theory is expressed from the point that increasing the pressure supplying the entire system pressure. The results showed that by increasing the pressure, the mounts of hydrogen and carbon monoxide are reduced and the high heating value slightly decreased (0/04 percent for a unit of pressure). Fifth Scenario is done because of changing biomass humidity in different situations and exigency of anticipating the exhaust gas composition.The results showed that the amount of carbon monoxide decreases with increasing humidity. These changes for using in the internal combustion engine is important because carbon monoxide can cause hot spots in the engine. Increased moisture in biomass increased hydrogen, moisture, methane and carbon dioxide. Very slight reduction of High Heating Value and increase of water vapor, can be appropriate for the furnace energy demander because water vapor emission rate is very high and it makes more uniform the furnace temperature. At the end, The model was designed well that can be used in choosing the optimized moisture condition as the demanders and designers ordered
- Keywords:
- Biomass ; Synthesis Gas ; Gasification Process ; Zone Modeling ; Preheating
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