A Simplified Equilibrium Model for Simulating Entrained Flow Gasifiers
A simplified equilibrium model for entrained flow coal gasifiers is developed. The model is based on mass, energy balances, and homogenous gas-phase reaction equilibriums. The resulting set of non-linear equations was solved by Newton’s method which is im
- PDF / 684,662 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 77 Downloads / 221 Views
Abstract
A simplified equilibrium model for entrained flow coal gasifiers is developed. The model is based on mass, energy balances, and homogenous gas-phase reaction equilibriums. The resulting set of non-linear equations was solved by Newton’s method which is implemented by a user-friendly Excel-VBA program. Seven major species of product gas and gasification reaction temperature are calculated and found to be in a reasonable agreement with operation data reported in literature for both slurry-feed GE and dry feed Shell gasifiers. A series of calculations are carried out to investigate the effects of different operation parameters on the performance of gasifier. The mechanism of these effects is analyzed and the model could be used for more applications to optimize the operation of gasifiers. Keywords
Gasification
Simulation
Modeling
Nomenclature
G V Mt C H O N S A pt Yi K P T
Mass flow rate of material entering or leaving the gasifier (kg/h) Volume flow rate of material entering or leaving the gasifier (m3/h) Total moisture concentration in coal (wt%) Carbon concentration (wt%) Hydrogen concentration (wt%) Oxygen concentration (wt%) Nitrogen concentration (wt%) Sulfur concentration (wt%) Ash concentration (wt%) Purity of oxygen entering the gasifier (wt%) Volume concentration of ith species in syngas (vol.%) Equilibrium constant Gasifier operating pressure (atm) Gasification reaction temperature (K)
Z. Liu F. Zhang National Institute of Clean-and-Low-Carbon Energy, Beijing 102209, People’s Republic of China Z. Liu J. Zhang (&) Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, People’s Republic of China e-mail: [email protected] © Springer Science+Business Media Singapore and Tsinghua University Press 2016 G. Yue and S. Li (eds.), Clean Coal Technology and Sustainable Development, DOI 10.1007/978-981-10-2023-0_72
531
532
Z. Liu et al.
m h Cp TO, TIN, TOUT
Mass flow rate of streams entering or leaving the gasifier (kg/h) Low heating value of streams entering or leaving the gasifier (kJ/kg) Specific heat capacity [kJ/(kg K)] Temperature of reference, inlet and outlet of gasifier, respectively (K)
Subscript
a c d g i o s A LOSS
1
Slag and ash Coal Dry base Syngas The ith gas species or ith streams Oxygen Steam Ash Heat loss of gasifier
Introduction
Coal gasifiers play a key role in modern clean coal conversion processes and IGCC (Integrated Gasification Combined Cycle). The accurate prediction of the performance of a gasifier, especially the product syngas composition under different operation conditions, is crucial to conduct system analysis and engineering design for gasifiers. The coal gasification reaction is a very complex system, and there were many reported studies on the gasification reaction mechanisms, both theoretically and experimentally. Mathematical models are also employed to calculate the product syngas composition; however, due to the complexity of a gasification process, some model
Data Loading...
