Thermodynamic modeling of gasification process provides a quick estimate of performance of the gasifier. Most of the earlier work on thermodynamic modeling is restricted to a particular feedstock-gasification agent combination and hence the results cannot be generalized. In the present work, the equilibrium modeling based on Gibbs free energy minimization approach is used to analyze the performance of gasification of any fuel using oxygen or steam. The performance is analyzed at the carbon boundary point at which the cold gas efficiency is maximum. The gasification temperature, amount of gasification agent required, composition of syngas, and cold gas efficiency are predicted using Aspen Plus. The results are presented as contour plots on Van Krevelen coordinates (H/C vs O/C) and interpreted based on simplified gasification reactions. The performance for different feedstocks represented in Van Krevelen diagram is also analyzed. Finally, advantage of cogasification of feedstocks is highlighted. © 2011 American Chemical Society.

T Renganathan

Department Of Chemical Engineering

Subramaniam Pushpavanam

Anapagaddi Ravikiran

ASPEN PLUS

Boundary points

Co-gasification

COLD GAS EFFICIENCY

Contour plot

Equilibrium modeling

Gasification process

Gasification reaction

GASIFICATION TEMPERATURES

Gasifiers

GIBBS FREE ENERGY MINIMIZATION

Syn-gas

THERMODYNAMIC MODELING

Feedstocks

Synthesis gas

Gasification

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Industrial and Engineering Chemistry Research

Plasma gasification is a process intensification technique in which the prevailing high temperatures accelerate the reactions resulting in a significant size reduction of the gasifier. Conventionally, a gasifier is modeled using either a thermodynamic or a kinetic approach. Present work proposes a novel method of modeling the plasma gasification process which combines these two approaches. The process is modeled as a combination of two regions: a Plasma Gasifier Zone (PGZ) and a Quenching Zone (QZ). PGZ, where gasification of feedstock takes place at high temperatures is modeled by thermodynamic equilibrium. QZ, where the syngas produced in the PGZ cools down, is modeled by kinetic approach. The hybrid approach captures the behavior more accurately and requires less computational effort. The proposed hybrid model is validated with experimental data from literature. The model is used to analyze the influence of radicals in plasma gasification and the performance for different operating conditions. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2592–2602, 2018. © 2018 American Institute of Chemical Engineers

AIChE Journal

A hybrid thermo-kinetic model for high temperature plasma gasification

In this work, a thermodynamic analysis of a stand alone gasifier is carried out. The analysis uses the nonstoichiometric approach based on the minimization of the Gibbs free energy. The gasification temperature, amount of oxygen required, composition of syngas, and cold gas efficiency are predicted at the carbon boundary point (CBP) using Aspen Plus. The influence of nitrogen when air is used as the gasifying agent is studied. It is found that the presence of nitrogen results in a lower gasification temperature, higher oxygen requirement, lower concentration of CO and H2, higher concentration of CO2 and CH4, and lower cold gas efficiency. The influence of pressure when air is used as the gasifying agent is also studied. It is found that increasing the pressure results in higher gasification temperatures, higher oxygen requirement, lower concentration of CO and H2, higher concentration of CO2 and CH4, and lower cold gas efficiency. Performance charts in the form of contour plots are presented to predict the performance of a high pressure gasifier using air as gasifying agent. © 2014 American Chemical Society.

Generalized thermodynamic analysis of high pressure air blown gasifier

A thermodynamic analysis of gasification of carbonaceous feedstocks using carbon dioxide and a mixture of carbon dioxide with steam or oxygen is carried out using Gibbs minimization approach. Simulations are carried out to study the effect of different operating conditions on the gasifier performance using Aspen Plus. Gasification using CO 2 at ambient conditions is not favorable under adiabatic condition. Complete carbon conversion can be obtained by increasing the operating temperature or flowrate of carbon dioxide. A cold gas efficiency greater than 1 is obtained under certain operating conditions. Maximum carbon dioxide conversion is obtained at the carbon boundary point. Based on the minimum energy requirement for complete carbon conversion, a universal optimal operating temperature of 850°C has been identified for gasification of any feedstock. Biomass requires less heat input compared to coal. Use of steam or oxygen as a cogasifying agent reduces the carbon dioxide and energy requirement but reduces carbon dioxide conversion. Syngas with a wide ranging ratio of hydrogen/carbon monoxide can be obtained using carbon dioxide gasification. Trends of simulation predictions are qualitatively consistent with experimental observations. © 2012 Elsevier Ltd.

Chemical Engineering Science

CO 2 utilization for gasification of carbonaceous feedstocks: A thermodynamic analysis

Fuel

Two-stage equilibrium model applicable to the wide range of operating conditions in entrained-flow coal gasifiers

Industrial & Engineering Chemistry Research

Biomass Catalytic Steam Gasification Thermodynamics Analysis and Reaction Experiments in a CREC Riser Simulator

Gasification and the Future

Volume 8: Energy Systems: Analysis, Thermodynamics and Sustainability; Sustainable Products and Processes

Modeling Biomass Gasification: A New Approach to Utilize Renewable Sources of Energy

Energy

Thermodynamic equilibrium model and second law analysis of a downdraft waste gasifier

Generalized analysis of gasifier performance using equilibrium modeling

Journal	Industrial and Engineering Chemistry Research
ISSN	08885885
Open Access	No