Coal Combustion Characteristics in a Pressurized Fluidized Bed

Keun-Hee Han; Jaehyeon Park; Jung-In Ryu; Gyoung-Tae Jin

Korean Journal of Chemical Engineering, Vol.16, No.6, 804-809, November, 1999

Keun-Hee Han¹, Jaehyeon Park¹, Jung-In Ryu^{1, 2}, and Gyoung-Tae Jin^{1, 3}

¹Korea Institute of Energy Research, Korea
²Chungnam National University, Taejon, Korea
³, Korea

The characteristics of emission and heat transfer coefficient in a pressurized fluidized bed combustor are investigated. The pressure of the combustor is fixed at 6 atm. and the combustion temperatures are set to 850, 900, and 950 degrees C. The gas velocities are 0.9, 1.1, and 1.3 m/s and the excess air ratios are 5, 10, and 20%. The desulfurization experiment is performed with limestone and dolomite and Ca/S mole ratios are 1, 2, and 4. The coal used in the experiment is Cumnock coat from Australia. All experiments are executed at 2 m bed height. In this study, the combustion efficiency is higher than 99.8% through the experiments. The heat transfer coefficient affected by gas velocity, bed temperature and coal feed rate is between 550-800 W/m(2) degrees C, which is higher than those of AFBC and CFBC. CO concentration with increasing freeboard temperature decreases from 100 ppm to 20 ppm. NOx concentration in flue gas is in the range of 5-130 ppm and increases with increasing excess air ratio. N2O concentration in flue gas decreases from 90 to 10 ppm when the bed temperature increases from 850 to 950 degrees C.

Keywords:Pressurized Fluidized Bed Combustion;Heat Transfer Coefficient;Flue Gas Emissions

[References]

Allen D, Hayhurst AN, "The Reduction of Nitric Oxide by Carbon Monoxide in a Fluidized Bed," Conf. 11th On Fluidized Bed Combustion, London, December, 221 (1991)
Anthony EJ, Preto F, "Pressurized Combustion in FBC Systems," In Pressurized Fluidized Bed Combustion (Ed. Cuenca and Anthony), 80 (1995)
Devaru C, Kolar A, "Heat Transfer from a Horizontal Finned Tube Bundle in Bubbling Fluidized Beds of Small and Large Particles," Proc. of the 13th International Conf. on FBC, 461 (1995)
Grace JR, Can. J. Chem. Eng., 64, 353 (1986)
Johnsson JE, Fuel, 73, 1398 (1994)
Johnsson J, Dam-Johansen K, "Reduction of N₂O over Char and Bed Material from CFBC," Proc. of the 13th International Conf. on FBC, 859 (1995)
Kim H, Park D, Korean J. Chem. Eng., 4(2), 143 (1987)
Lyngfet A, Leckner B, "The Effect of Reductive Decomposition of CaSO₄ on Sulphur Capture in Fluidized Bed Boilers," Proc. of the 10th International Conf. on FBC, 675 (1989)
McCabe WL, Smith JC, "Unit Operations of Chemical Engineering," 3rd Edition, McGraw-Hill, 302 (1976)
McClung JD, Provol SJ, Morehead HT, Dodd AM, "The Lakeland Mclntosh Unit 4 Demonstration Project Utilizing Foster Wheeler's Pressurized Circulating Fluidized-Bed Combustion Technology," Proc. of the 14th International Conf. on FBC, 79 (1997)
Mcdonald DK, Anderson J, "Comparison of Bubbling and Circulating Pressurized Fluidized Bed Combustion," Proc. of the 12th International Conf. on FBC, 555 (1993)
Miller CL, "Commercialization and Future Role of Pressurized Bed Combustion as a Clean Coal Technology," International Clean Coal Technology Symposium on PFBC, July 26-28, Kitakyusyu, Japan, 65 (1994)
Moritomi H, "Pressurized Fluidized Bed Combustion," APEC CCT Training Course, Sydney, Nov. (1994)
Podolski WF, Miller SA, Vogel GJ, Gehl SM, Hanway JE, Henry RF, Smyk EB, Swift WM, Parker KM, Graves RL, Griffin FP, Lackey ME, "Pressurized Fluidized Bed Combustion Technology," Noyes Data Corporation, 272 (1983)
Sarofim AF, "Fluidized Bed Combustion and Emission Control Issues," International Clean Coal Technology Symposium on PFBC, July 26-28, Kitakyusyu, Japan, 11 (1994)
Shun D, Bae DH, Han KH, Son JE, Kang Y, Wee YH, Lee JS, Ji PS, HWAHAK KONGHAK, 34(3), 321 (1996)
Tomuro J, Hokari N, Miyamoto T, Yoshii Y, Oki K, "Reduction of NO During Load Change Through the Operations of a 2MWth PFBC Unit," Proc. of the 11th International Conf. on FBC, 97 (1995)
Wallman PH, Carlsson RCJ, "Fluidized Bed Combustion Kinetics at Elevated Pressures," Proc. of the 11th International Conf. on FBC, 1517 (1991)
Wedel G, Krein J, Mollenhoff H, Rehwinkel H, Winkler K, "Pressurized Fluidized Bed Combustion in a 15MWth Test Facility Bubbling and Circulating Experience and Future Development," Proc. of the 12th International Conf. on FBC, 403 (1993)

[Referenced By]

[1] Allen D, Hayhurst AN, "The Reduction of Nitric Oxide by Carbon Monoxide in a Fluidized Bed," Conf. 11th On Fluidized Bed Combustion, London, December, 221 (1991)

[2] Anthony EJ, Preto F, "Pressurized Combustion in FBC Systems," In Pressurized Fluidized Bed Combustion (Ed. Cuenca and Anthony), 80 (1995)

[3] Devaru C, Kolar A, "Heat Transfer from a Horizontal Finned Tube Bundle in Bubbling Fluidized Beds of Small and Large Particles," Proc. of the 13th International Conf. on FBC, 461 (1995)

[4] Grace JR, Can. J. Chem. Eng., 64, 353 (1986)

[5] Johnsson JE, Fuel, 73, 1398 (1994)

[6] Johnsson J, Dam-Johansen K, "Reduction of N₂O over Char and Bed Material from CFBC," Proc. of the 13th International Conf. on FBC, 859 (1995)

[7] Kim H, Park D, Korean J. Chem. Eng., 4(2), 143 (1987)

[8] Lyngfet A, Leckner B, "The Effect of Reductive Decomposition of CaSO₄ on Sulphur Capture in Fluidized Bed Boilers," Proc. of the 10th International Conf. on FBC, 675 (1989)

[9] McCabe WL, Smith JC, "Unit Operations of Chemical Engineering," 3rd Edition, McGraw-Hill, 302 (1976)

[10] McClung JD, Provol SJ, Morehead HT, Dodd AM, "The Lakeland Mclntosh Unit 4 Demonstration Project Utilizing Foster Wheeler's Pressurized Circulating Fluidized-Bed Combustion Technology," Proc. of the 14th International Conf. on FBC, 79 (1997)

[11] Mcdonald DK, Anderson J, "Comparison of Bubbling and Circulating Pressurized Fluidized Bed Combustion," Proc. of the 12th International Conf. on FBC, 555 (1993)

[12] Miller CL, "Commercialization and Future Role of Pressurized Bed Combustion as a Clean Coal Technology," International Clean Coal Technology Symposium on PFBC, July 26-28, Kitakyusyu, Japan, 65 (1994)

[13] Moritomi H, "Pressurized Fluidized Bed Combustion," APEC CCT Training Course, Sydney, Nov. (1994)

[14] Podolski WF, Miller SA, Vogel GJ, Gehl SM, Hanway JE, Henry RF, Smyk EB, Swift WM, Parker KM, Graves RL, Griffin FP, Lackey ME, "Pressurized Fluidized Bed Combustion Technology," Noyes Data Corporation, 272 (1983)

[15] Sarofim AF, "Fluidized Bed Combustion and Emission Control Issues," International Clean Coal Technology Symposium on PFBC, July 26-28, Kitakyusyu, Japan, 11 (1994)

[16] Shun D, Bae DH, Han KH, Son JE, Kang Y, Wee YH, Lee JS, Ji PS, HWAHAK KONGHAK, 34(3), 321 (1996)

[17] Tomuro J, Hokari N, Miyamoto T, Yoshii Y, Oki K, "Reduction of NO During Load Change Through the Operations of a 2MWth PFBC Unit," Proc. of the 11th International Conf. on FBC, 97 (1995)

[18] Wallman PH, Carlsson RCJ, "Fluidized Bed Combustion Kinetics at Elevated Pressures," Proc. of the 11th International Conf. on FBC, 1517 (1991)

[19] Wedel G, Krein J, Mollenhoff H, Rehwinkel H, Winkler K, "Pressurized Fluidized Bed Combustion in a 15MWth Test Facility Bubbling and Circulating Experience and Future Development," Proc. of the 12th International Conf. on FBC, 403 (1993)