Emissions Reduction by Combustion Modeling in the Riser of Fluidized Bed Combustor for Thar Coal Pakistan
Thar coal emission reduction by combustion modeling
DOI:
https://doi.org/10.53560/PPASB(59-4)754Keywords:
Two-phase gas-solid flow model, Thar coal, Circulating fluidized bed, Hydrodynamic, Computational fluid dynamics, Riser, Emissions reductionAbstract
Pakistan has experienced a protracted electricity shortage for the past few years. However, despite Pakistan’s abundant coal deposits, modern coal combustion technology is still required to reduce emissions. Pakistan is struggling to utilize its energy resources and currently experiencing an electrical shortage of more than 8000 MW. The research study models the combustion performance in a fluidized bed riser using ANSYS FLUENT software to understand the combustion behavior of low-rank Thar coal. A simple circulating fluidized bed (CFB) combustion riser was modeled for computational fluid dynamics (CFD) to study the hydrodynamics of gas-solid flow in a circulating fluidized bed riser to reduce emissions and operating costs. Three different types of risers/combustors geometries were used center flow, counter flow, and parallel flow. The CFD model for the solids segment with a k-e turbulence model and the viscosity of static particles in the gas segment both showed excellent mixing performance. According to the FLUENT data, the riser/combustor maximum temperature is around 1400 K or 1130 o C at the primary burning sector in the bed center. According to velocity contours, the greatest velocity in the center-oriented riser/combustor peaks at 3.3 m/s. The CO and CO2 both mass fraction counters show maximum concentration in the center geometry, whereas lower CO concentration is found in parallel geometry. The lowest level of NOx is established in the parallel geometry at around 15 ppm, whereas the counter contours establish the maximum level of NOx at about 31 ppm. Circulating Fluidized Bed Combustor is found to be the most advantageous and effective technology for producing power from Thar lignite coal and reducing emissions.
References
IEP. Pakistan Energy Outlook Report 2021-2030. Integrated Energy Planning for Sustainable Development. Ministry of Planning, Development & Special Initiatives Government of Pakistan (2022). https://www.pc.gov.pk/uploads/report/IEP_Report_FINAL.pdf.
G. Chapman. Global Thermal Coal Supply Fundamentals. ICSC Report # ICSC/318. International Centre for Sustainable Carbon (2022).
Available at: https://www.sustainable-carbon.org/login/?download-id=40758.
M. Manook. Stop wordsmithing around coal. Financial Times (2021). Available at: https://www.ft.com/content/30fc0408-3d7a-4490-ab09-81ff2393305a. (accessed 11 August 2022).
EIU. Betting on coal to solve the electricity shortage. The Economist Intelligence Unit report (2017).
http://www.eiu.com/industry/article/825415066/betting-on-coal-to-solve-the-electricityshortage/2017-05-11. (accessed 11 May 2017).
NTDC. Indicative Generation Capacity Expansion Plan IGCEP 2021-30. Power System Planning Report, May 2021. National Transmission and Dispatch Company (2021). https://nepra.org.pk/Admission%20Notices/2021/06%20June/IGCEP%202021.pdf.
BP. Annual BP Statistical Review of World Energy, 2020. 69th edition. British Petroleum Company (2020). Available at: https://www.bp.com/content/dam/bp/business-sites/en/global/corporate/pdfs/energy-economics/statistical-review/bp-statsreview-2020-full-report.pdf. 65 pp.
A. Mashi. Thar Coalfield: Sustainable Development and an Open Sesame to the Energy Security of Pakistan. IOP Conf. Series: Journal of Physics: Conference Series, 989, 012004, Chiyi, Taiwan (2018). DOI: http://dx.doi.org/10.1088/1742-6596/989/1/012004.
X. Zhang. Blended Firing of Coal and Lignite. ICSC Report # ICSC/316. International Centre for Sustainable Carbon. ISBN 978–92–9029–639-3 (2021).
P. Diego. A study of an oxy-coal combustion with wet recycle using CFD modeling. ATI. Energy Procedia 82: 900-907 (2015). https://doi.org/10.1016/j.egypro.2015.11.837.
L. Zheng. Oxy-fuel combustion for power generation and carbon dioxide (CO2) capture. 1st Edition, ISBN: 978-1-84569-671-9. Woodhead Publishing Limited (2011).
X. Liu, H. Yang, and J. Lyu. Optimization of Fluidization State of a Circulating Fluidized Bed Boiler for Economical Operation. Energies 13 (376) (2020). Doi: 10.3390/en13020376.
W.A. Khan, K. Shahzad, M. Saleem, N.A. Akhtar, and S. Tahir. Radial heat transfer investigation in a circulating fluidized bed burning makarwal coal. Journal of Faculty of Engineering & Technology 18 (1): 59-70 (2011).
S.N. Kishore, T.V. Rao, and M.L. Kumar. Furnace design of 210 mw circulating fluidized bed boilernumerical investigation. International Journal of Mechanical Engineering and Technology (IJMET) 8 (3): 442–455 (2017).
Y. Göğebakan, Simulation of Circulating Fluidized Bed Combustors. A Ph.D. Thesis. Middle East Technical University, Ankara, Turkey (2006).
Y. Liu, P. Huo, X. Li, and H. Qi. Numerical analysis of the operating characteristics of a large-scale CFB coal-gasification reactor with the QC-EMMS drag model. Canadian Journal of Chemical Engineering 99:1390–1403 (2020). DOI: 10.1002/cjce.23911.
Y. Yuan, Y. He, J. Tan, Y. Wang, S. Kumar, and Z. Wang. Co-Combustion Characteristics of Typical Biomass and Coal Blends by Thermo gravimetric Analysis. Frontiers in Energy Research 9:753622 (2021). Doi: 10.3389/fenrg.2021.753622.
A. Hussain. Hydrodynamic and Thermo gravimetric Studies of Palm Shell Waste and Coal Blends in a Circulating Fluidized Bed Riser. A PhD thesis by Ahmed Hussain. Department of Mechanical Engineering, University Technology Malaysia, Johor Bharu, Malaysia (2006).
Thar coal emission reduction by combustion modeling 69
A. Harris, J. Davidson, and R.B. Thorpe. Influence of Exit Geometry in Circulating Fluidized-Bed Risers. AIChE Journal 49 (1): 52-64 (2003). https://doi.org/10.1002/aic.690490107.
M.A. Raza, K.L. Khatri, M.A. Memon, K. Rafique, M.I.U. Haque, and N.H. Mirjat. Exploitation of Thar coalfield for power generation in Pakistan: A way forward to sustainable energy future. Energy Exploration & Exploitation 1–24 (2022). Doi: 10.1177/01445987221082190.
F. Kazanc. Gaseous and Particulate Emissions from Pulverized Coal and Biomass Combustion under Different O2/N2 and O2
/CO2 Environments. A Thesis by Feyza Kazanc, The Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts (2013).
G. Nely, D. Sivelina, and T. Petko. Analysis of the capabilities of software products to simulate the behavior of dynamic fluid flows. IOP Conf. Series: Materials Science and Engineering 1031 (2021) 012079. Doi:10.1088/1757-899X/1031/1/012079.
J. Peters, J. May, J. Ströhle, and B. Epple. The flexibility of CFB Combustion: An Investigation of Co-Combustion with Biomass and RDF at Part Load in Pilot Scale. Energies. 13 (8): 4665 (2020). https://doi.org/10.3390/en13184665.
A. Hussain, F. Junejo, M.N. Qureshi, and A. Haque. Hydrodynamic and combustion behavior of lowgrade coals in the riser of a circulating fluidized bed combustor. NUST Journal of Engineering Sciences 11(1): 1-11 (2018).
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