Showing 4 results for Gasification
Shoaib Khanmohammadi, Kazem Atashkari, Ramin Kouhi Kamali,
Volume 15, Issue 9 (11-2015)
Abstract
Many researchers have been considered biomass utilization due to reduction of greenhouse gas effects and environmental impact recently. Achieving a system with the best performance for the application of this type of fuel with low calorific value is to be one of the topics of interest to researchers. This study focus on precise modeling of biomass gasification and design a trigeneration system to produce cooling, heating and electricity using this clean source of energy. In the process modeling of biomass gasification a realistic model includes tar content in syngas is developed. A parametric study of trigeneration system to find the objective functions trend and to achieve the best performance parameter is carried out. Results show that two objective functions in the reasonable range have conflict which emphasis to the multi-objective optimization. Also, with draw Pareto front curve, a suitable relation to estimate the trend of objective functions is derived.
Ali Bahari, , Javad Mahmoudimehr,
Volume 18, Issue 6 (10-2018)
Abstract
The use of biomass by means of gasification to produce bio fuels and reducing the environmental impact of fossil fuels has been the focus of many researchers in recent years. In the present study, the computational fluid dynamics method is used to predict the process of gasification inside a downdraft gasifier. Recent studies have shown that although many studies have been carried out by various researchers to maximize the cold gas efficiency in the gasification process, so far, no study has been done to minimize the emission of pollutants as one of the other important design parameters along with the increase of cold gas efficiency. So, in this study, the effect of changing the equivalence ratio as design variable on the gasification efficiency as well as the amount of pollutant produced simultaneously is investigated. Also, in this study, CO/CO2 and H2 /H2O molar ratios are considered as another objective function in selecting the optimal process point. In order to verify the validity of the results, the simulation data was compared with the experimental results and the previous numerical study, and a good agreement was shown between their comparison. The results of this study show that in the ratio of 0.64, the rate of production of nitrogen oxides relative to cold gas efficiency is optimal considering the maximum production of CO/CO2 and H2/H2O molar ratios . This point is the optimal point. Under the working conditions of the gasification process.
M.a. Yazdanpanah Jahromi , K. Atashkari, M. Kalteh,
Volume 19, Issue 12 (12-2019)
Abstract
Gasification technology is an important part of clean coal technology. Further development of this technology requires understanding the processes and interactions of gas and solid fuel particles injected into the gasifier. In this study, a numerical simulation of an entrained flow coal gasifier has been investigated using experimental operating conditions. The reactions and kinetic parameters of the gasification process have been extracted using coal gasification data obtained from similar published papers. Comparison of the simulation results with experimental data and two other similar studies confirm the accuracy of the developed model. The focus of this study is on the accuracy of the models presented for the devolatilization process and the effect of the oxidizer change from oxygen to air on the gasifier performance. Four devolatilization models including chemical percolation devolatilization, single rate, Kobayashi and constant rate models have been investigated. The predicted trends of species changes are similar in different devolatilization models but the amount of produced syngas is somewhat different depending on the accuracy of each model. The Kobayashi and constant rate models predict the devolatilization rate lower than the other two models. The results obtained from the chemical percolation devolatilization model are more consistent with the experimental data compared to the other models but require higher computational times. The use of air oxidizing agents reduces the concentration of produced syngas rather than oxygen and hence reduces the gasifier efficiency.
E. Shayan, V. Zare, I. Mirzaee,
Volume 20, Issue 3 (2-2020)
Abstract
In recent years, the integration of biomass gasification with solid oxide fuel cells offers an emerging alternative for conventional power generation systems. Also, due to the ever-increasing human need for drinking water and the limitation of available drinking water resources, the desalination of the oceans saltwater is one of the promising solutions for the water scarcity problem. Therefore, in the present study, a novel integrated system containing steam biomass gasification, solid oxide fuel cell and multi-effect desalination system is introduced. Modeling and exergoeconomic analysis of the system is performed in EES software. A parametric study is conducted to examine the effects of key operating parameters on the net output power, exergy efficiency and unit product cost of the integrated system. The results indicate that the exergy efficiency and unit product cost of the integrated system are obtained 46.04% and 4.57$/GJ respectively.
