(Pdf) using a simple modeling and simulation scheme for complicated gasification system gas 85

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Gasification processes are complicated with numerous parameters. It makes us difficult to understand the whole process nature. Therefore, a simplified approach based on modified stoichiometric equilibrium model for downdraft gasifier is designed in order to simulate the overall gasification process. The model uses the chemical reactions and species involved, while it starts by selecting all species containing C, H, O and N. Mass and energy balances of the gasifier-coupled with two equilibrium reactions are incorporated to create the model. This model can be solved with user friendly Micorsoft Excel and nonlinear electricity usage calculator Matlab solver. To validate the model, a close agreement is shown between numerical and experimental results within the same configuration. It can predict the composition of producer gases and heating values with acceptable accuracy. After validation, it is simulated to study the effects of temperature, moisture content of biomass and air-fuel ratio (related to equivalence ratio) in the downdraft gasifier. And then, experiments are conducted using optimized simulation data obtained from the model and it was found that the output producer gases were a close agreement with model results in producer gas composition and heating value.

The aim of this work is to develop stoichiometric equilibrium models that permit the study of parameters effect in the gasification process of a particular feedstock. In total four models were tested in order to determine the syngas composition. One of these four models, called M2, was based on the theoretical equilibrium constants modified by two correction factors determined using published experimental data. The other two models, M3 and M4 were based in correlations, while model M4 was based in correlations to determine the equilibrium constants, model gasco abu dhabi address M3 was based in correlations that relate the H2, CO and CO2 content on the synthesis gas. Model M2 proved to be the more accurate and versatile among these four models, and also showed better results than some previously published models. Also a case study for the gasification of a blend of hardwood chips and glycerol at 80% and 20% respectively, was performed considering equivalence ratios form 0.3 to 0.5, moisture contents from 0%–20% and oxygen percentages in the gasification agent of 100%, 60% and 21%.

A gasifier has been fabricated in Sri Lanka for the tea industry, but there is a lack of knowledge of the effect of certain key operating parameters and design features on its performance. Experimental testing of the design under various conditions has produced data that has then been used to calibrate a computer program, developed to investigate the impact of those parameters and features on conversion efficiency. The program consists of two sub-models of the pyrolysis and gasification zones, respectively. The pyrolysis sub-model has been used to determine the maximum temperature and the composition of the gas entering the gasification gas definition physics zone. The gasification zone sub-model has been calibrated using data gathered from the experiments. It was found that a wood chip size of 3– with a moisture content below 15% (d.b.) should be used in this gasifier. Feed material with a fixed carbon content of higher than 30% and heat losses of more than 15% should be avoided. For the above parameters, the gasification zone should be long to achieve an acceptable conversion efficiency.

Seeking appropriate approaches to utilize the crude glycerol produced in biodiesel production is very important for the economic viability and environmental impacts of biodiesel industry. Gasification may be one of options for addressing this issue. Co-gasification of hardwood chips blending with crude glycerol in various loading levels was undertaken in the study involving a pilot scale fixed-bed downdraft gasifier. The results indicated that crude glycerol loading levels affected the gasifier’s performance and the quality of syngas produced. When crude glycerol loading level increased, the CO, CH(4), and tar concentrations of the syngas also increased but particle concentration decreased. Though further testing is suggested, downdraft gasifiers could be run well with hardwood chips blending with liquid crude glycerol up to 20 (wt%). The syngas produced had relatively good quality for fueling internal combustion engines. This study provides a considerable way to utilize crude glycerol.

A simplified approach based on modified stoichiometric equilibrium model for downdraft gasifier is designed in order to simulate the overall gasification process. The model uses the chemical reactions and species involved, while it starts by selecting all species containing C, H, O and N. Mass and energy balances of the gasifier-coupled with two equilibrium reactions are wd gaster battle incorporated to create … [Show full abstract] the model. This model can be solved with user friendly Micorsoft Excel and nonlinear Matlab solver. To validate the model, a close agreement is shown between numerical and experimental results within the same configuration. It can predict the composition of producer gases and heating values with acceptable accuracy. After validation, it is simulated to study the effects of temperature, moisture content of biomass and air-fuel ratio (related to equivalence ratio) in the downdraft gasifier. Therefore, the developed model in this study provides not only a tool for design optimization of a downdraft gasifier but also a teaching aid for thermochemical gasification system. View full-text

This paper hp gas aims at presenting a numerical study considering the effect of oxygen concentration varied from 21% (v/v) to 40% (v/v) in enriched-air-pine biomass gasification. The gasification technology still to be in the early stage of development in Portugal and numerical studies to describe potential scenarios of biomass usage (a large amount of pine residues are available) are needed. The study … [Show full abstract] was carried out considering a thermodynamic dual stage model developed using the Matlab program. The concept of carbon boundary point (CBP) was used to study the effect of different operating conditions, namely, pressure, moisture, the steam-to-biomass ratio and the adiabatic versus allothermal condition at the optimum gasification point. From the numerical simulation, it was observed that the gasification temperature increases with the operating pressure for all experimented oxygen concentrations and decreases with the moisture content as a function of the oxygen content. The molar fraction of the hydrogen and carbon monoxide at the CBP decreases as a function of the oxygen content while that of the carbon dioxide and methane increases. Finally, it was concluded that both the energy and exergy efficiencies also increase with the oxygen content. Read more

A thermo-chemical equilibrium model is applied to predict the released syngas composition, char, tar content and temperature in biomass gasifiers. The accuracy of the model results is improved by proper calibration, namely by modifying the equilibrium constants through correction factors grade 9 electricity quiz that represent the degree of approach of the analyzed system to equilibrium. To this aim, the developed model … [Show full abstract] is coupled with a genetic algorithm (Moga II), to search for the optimal correction factors able to minimize the error between the computed and the experimentally measured product yields and temperatures. The approach is repeated to simulate the thermal treatment of different biomasses with increasing carbon content, from straw to sawdust. The possibility to resort to a unique set of correction factors for different biomasses is explored, that would allow the model being of particular interest for engineering applications, to trace the design guidelines for gasification systems. View full-text