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

Shanmughom Rupesh,Chandrasekharan Muraleedharan,Palatel Arun

doi:10.1155/2014/654946

Shanmughom Rupesh, Chandrasekharan Muraleedharan + Show 1 more

Open Access

https://doi.org/10.1155/2014/654946

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Abstract

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.

Highlights

Gasification is a thermochemical process by which low energy density fuels like biomass can be converted into gaseous fuels with the aid of a series of chemical reactions
It was concluded that in spite of low ash melting point and high dust content in the product gas, fluidised bed gasifiers have higher heat and mass transfer compared to fixed bed, which result in better temperature distribution
The modified quasi-equilibrium model is used to predict the influence of key process parameters like temperature, steam to biomass ratio (SBR), and equivalence ratio (ER) on product gas composition, heating value, and gasification efficiency

Summary

Introduction

Gasification is a thermochemical process by which low energy density fuels like biomass can be converted into gaseous fuels with the aid of a series of chemical reactions. A pseudoequilibrium air-steam gasification model with correction factors for equilibrium constants in terms of reactor temperature was developed by Ng et al [10] This model considered tar as a compound containing carbon, hydrogen, and oxygen, and char as solid carbon. Puig-Arnavat et al [22] developed a modified equilibrium model for air steam gasification of biomass using Engineering Equation Solver (EES). Deviation of this model from pure equilibrium is minimised by considering pyrolysis, heat loss in pyrolysis, char and tar, and particles leaving the gasifier and setting the amount of CH4 produced. A locally available nonedible biomass waste, is the feedstock selected for the study

Model Development

Model Validation

Model Modification

Model Application

Results and Discussion

Conclusion