Numerical Simulation of Stoichiometric Thermodynamic Equilibrium Model of a Downdraft Biomass Air Gasifier

The gasification of biomass resources is considered a promising route for the production of clean energy fuels for the future.The product gas of partial combustion of biomass with air as the gasifying medium is the mixture of CO, H2, CH4, CO2, H2Oand N2 called syngas. Syngas generation is now considered matured and acceptable technology compared to other biomassconversion technologies. In this study, a thermodynamic equilibrium model to determine syngas composition based on carbon,hydrogen and oxygen obtained from composite agricultural wastes was developed. For these materials, at preset gasificationtemperature of 750oC, the effects of changes in moisture content and air/fuel ratio on the quality syngas composition weremodeled. The yields of combustible gases (H2, CO and CH4) from Rice husk briquette were observed to be generally higherthan those of groundnut shell with sawdust briquette. The result with Groundnut shell and Sawdust briquette as input indicatedthat the fraction of H2, CO and CH4 gradually decreased, while the concentration of CO2 and H2O increased when moisturecontent increases from 0% to 45%. Similar trend was observed from the analysis of Rice husk briquette gasification in the model.The amount of Air per kmol of fuel varied from 0 to 1.0. As a result, the H2, CO and CH4 content of syngas for Groundnutshell and sawdust briquette decreased continuously; with CH4 approaching zero at air/fuel ratio of unity. Similar trend occurredin Rice husk briquette, but the values were higher than those observed for the groundnut shell & sawdust briquette. The amountof CO2 and H2O increased from 14.9742% and 20.6603% to 36.5886% and 57.3208% respectively for Groundnut shell briquette,while for Rice husk briquette the amount of CO2 and H2O rose from initial values of 2.8047% and 2.2552% at zero air/fuelratios to 40.3272% and 45.6339% respectively.The results of this study would be useful for the engineering development of biomass gasification power generation technologiesand in the selection of appropriate feedstock.

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Analysis of Hydrogen Generation through Thermochemical Gasification of Coconut Shell Using Thermodynamic Equilibrium Model Considering Char and Tar

International Scholarly Research Notices ◽

10.1155/2014/654946 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 7

Author(s):

Shanmughom Rupesh ◽

Chandrasekharan Muraleedharan ◽

Palatel Arun

Keyword(s):

Thermodynamic Equilibrium ◽

Equilibrium Model ◽

Equivalence Ratio ◽

Equilibrium Constants ◽

Steam Gasification ◽

Coconut Shell ◽

Heating Value ◽

Product Gas ◽

Biomass Ratio ◽

Thermodynamic Equilibrium Model

This work investigates the potential of coconut shell for air-steam gasification using thermodynamic equilibrium model. A thermodynamic equilibrium model considering tar and realistic char conversion was developed using MATLAB software to predict the product gas composition. After comparing it with experimental results the prediction capability of the model is enhanced by multiplying equilibrium constants with suitable coefficients. The modified model is used to study the effect of key process parameters like temperature, steam to biomass ratio, and equivalence ratio on product gas yield, composition, and heating value of syngas along with gasification efficiency. For a steam to biomass ratio of unity, the maximum mole fraction of hydrogen in the product gas is found to be 36.14% with a lower heating value of 7.49 MJ/Nm3 at a gasification temperature of 1500 K and equivalence ratio of 0.15.

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Characterization of Atmospheric PM2.5 Inorganic Aerosols Using the Semi-Continuous PPWD-PILS-IC System and the ISORROPIA-II

Atmosphere ◽

10.3390/atmos11080820 ◽

2020 ◽

Vol 11 (8) ◽

pp. 820

Author(s):

Thi-Cuc Le ◽

Yun-Chin Wang ◽

David Y. H. Pui ◽

Chuen-Jinn Tsai

Keyword(s):

Thermodynamic Equilibrium ◽

Equilibrium Model ◽

Inorganic Ions ◽

Porous Metal ◽

Water Soluble ◽

Inorganic Aerosols ◽

Daily Data ◽

Water Soluble Inorganic Ions ◽

Thermodynamic Equilibrium Model ◽

Good Agreement

A semi-continuous monitoring system, a parallel plate wet denuder and particle into liquid sampler coupled with ion chromatography (PPWD-PILS-IC), was used to measure the hourly precursor gases and water-soluble inorganic ions in ambient particles smaller than 2.5 µm in diameter (PM2.5) for investigating the thermodynamic equilibrium of aerosols using the ISORROPIA-II thermodynamic equilibrium model. The 24-h average PPWD-PILS-IC data showed very good agreement with the daily data of the manual 5 L/min porous-metal denuder sampler with R2 ranging from 0.88 to 0.98 for inorganic ions (NH4+, Na+, K+, NO3−, SO42−, and Cl−) and 0.89 to 0.98 for precursor gases (NH3, HNO3, HONO, and SO2) and slopes ranging from 0.94 to 1.17 for ions and 0.87 to 0.95 for gases, respectively. In addition, the predicted ISORROPIA-II results were in good agreement with the hourly observed data of the PPWD-PILS-IC system for SO42− (R2 = 0.99 and slope = 1.0) and NH3 (R2 = 0.97 and slope = 1.02). The correlation of the predicted results and observed data was further improved for NH4+ and NO3− with the slope increasing from 0.90 to 0.96 and 0.95 to 1.09, respectively when the HNO2 and NO2− were included in the total nitrate concentration (TN = [NO3−] + [HNO3] + [HONO] + [NO2−]). The predicted HNO3 data were comparable to the sum of the observed [HNO3] and [HONO] indicating that HONO played an important role in the thermodynamic equilibrium of ambient PM2.5 aerosols but has not been considered in the ISORROPIA-II thermodynamic equilibrium model.

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