Simulation of circulating fluidized bed gasification for characteristic study of pakistani coal
A process model for turbulent pressurized circulating fluidized-bed coal gasifier is created using ASPEN PLUS software. Both hydrodynamic and reaction kinetics parameter are taken into account, whose expressions for fluidized bed are adopted from the literature. Various reactor models available in ASPEN PLUS with calculator as External Block are nested to solve hydrodynamics and kinetics. Multiple operational parameters for a pilot-plant circulating fluidized-bed coal gasifier are used to demonstrate the effects on coal gasification characteristics. This paper presents detailed information regarding the simulation model, including robust analysis of the effect of stoichiometric ratio, steam to coal ratio, gasification temperature and gasification agent temperature. It is observed that, with the increase in the flow rate of air, the components hydrogen, carbon monoxide, carbon dioxide and methane reduce, which causes the Lower Heating Value (LHV) of synthesis gas (Syn. Gas) to decrease by about 29.3%, while increment in the steam flow rate shows a minute increase in heating value of only 0.8%. Stoichiometric ratio has a direct relationship to carbon conversion efficiency and carbon dioxide production. Increasing the steam to coal ratio boosts the production of hydrogen and carbon monoxide, and causes a drop in both carbon dioxide concentration and the conversion efficiency of carbon. High gasifying agent temperature is desired because of high concentration of CO and H2, increasing carbon conversion and LHV. A high gasifying agent temperature is the major factor that affects the coal gasification to enhance H2 and CO production rapidly along with other gasification characteristics.
- University of Engineering and Technology, Department of Chemical Engineering, G.T. Road, Lahore 54890, Pakistan
- Project Development Directorate, DH Fertilizers Limited, 28-km Lahore Sheikhupura Road, Lahore, Pakistan
- School of Engineering and Technology, Faculty of Sciences, Engineering and Health Central Queensland University, Rockhampton, Qld 4702, Australia
- University of Engineering & Technology (Lahore) Faisalabad Campus, Department of Chemical & Polymer Engineering, Faisalabad, Pakistan, Syed.firstname.lastname@example.org
- Pakistan Institute of Contemporary Sciences, Raiwind Lahore, Pakistan
- 1. Mirza, U.K., Ahmad, N. & Majeed, T. (2008). An overview of biomass energy utilization in Pakistan. Renew. Sust. Energ. Rev. 12(7), 1988-1996. DOI: 10.1016/j.rser.2007.04.001.[WoS][Crossref]
- 2. Asif, M. (2009). Sustainable energy options for Pakistan. Renew. Sust. Energ. Rev. 13(4), 903-909. DOI: 10.1016/j. rser.2008.04.001.[WoS][Crossref]
- 3. Ju, F., Chen, H., Yang, H., Wang, X., Zhang, S. & Liu, D. (2010). Experimental study of a commercial circulated fl uidized bed coal gasifier. Fuel Process. Technol. 91(8), 818-822. DOI: 10.1016/j.fuproc.2009.07.013.[WoS][Crossref]
- 4. Bell, D.A., Towler, B.F. & Fan, M. (2011). Coal gasification and its applications (1st ed). Oxford: William Andrew Publisher.
- 5. Nozawa, S. & Matsushita, Y. (2013). Numerical investigation of the effect of the heterogeneous reaction model on the thermal behavior of pulverized coal combustion. Asia-Pac. J. Chem. Eng. 8, 292-300. DOI: 10.1002/apj.1694.[WoS][Crossref]
- 6. Wu, L., Qiao, Y. & Yao, H. (2012). Experimental and numerical study of pulverized bituminous coal ignition characteristics in O2/N2 and O2/CO2 atmospheres. Asia-Pac. J. Chem. Eng. 7(S2), S195-S200. DOI: 10.1002/apj.590.
- 7. Basu, P. (2006). Combustion and gasification in fluidized beds. Boca Raton: CRC Press.
- 8. Ocampo, A., Arenas, E., Chejne, F., Espinel, J., Londono, C., Aguirre, J. & Perez, J. (2003). An experimental study on gasification of Colombian coal in fluidised bed. Fuel 82(2), 161-164. DOI: 10.1016/S0016-2361(02)00253-3.[Crossref]
- 9. Nikoo, M.B. & Mahinpey, N. (2008). Simulation of biomass gasification in fluidized bed reactor using ASPEN PLUS. Biomass Bioenerg. 32(12), 1245-1254. DOI: 10.1016/j. biombioe.2008.02.020.[Crossref][WoS]
- 10. Yan, H. & Zhang, D. (1999). Modeling of a low temperature pyrolysis process using ASPEN PLUS. Dev. Chem. Eng. Mineral Process. 7(5-6), 577-591. DOI: 10.1002/apj.5500070511.[Crossref]
- 11. Lee, J.M., Kim, Y.J., Lee, W.J. & Kim, S.D. (1998). Coal-gasification kinetics derived from pyrolysis in a fluidized- bed reactor. Energy 23(6), 475-488. DOI: 10.1016/S0360-5442(98)00011-5. [Crossref]
- 12. Duan, F., Jin, B., Huang, Y., Li, B., Wu, Y. & Zhang, M. (2010). Results of bituminous coal gasification upon exposure to a pressurized pilot-plant circulating fluidized-bed (CFB) reactor. Energ. Fuel. 24(5), 3150-3158. DOI: 10.1021/ef901596n.[WoS][Crossref]
- 13. Siddiqui, I. (2007) Environmental study of coal deposits of Sindh, with special reference to heavy and trace metal study in Thar, Sonda and Meting-Jhimpir coal field. PhD Thesis, University of Peshawar, Peshawar, Pakistan.