Simultaneous Carbonation and Sulfation of CaO in Oxy‐Fuel CFB Combustion

For anthracites and petroleum cokes, the typical combustion temperature in a circulating fluidized bed (CFB) is > 900 °C. At CO2 concentrations of 80–85 % (typical of oxy-fuel CFBC conditions), limestone still calcines. When the ash which includes unreacted CaO cools to the calcination temperature, carbonation of fly ash deposited on cool surfaces may occur. At the same time, indirect and direct sulfation of limestone also will occur, possibly leading to more deposition. In this study, CaO was carbonated and sulfated simultaneously in a thermogravimetric analyzer (TGA) under conditions expected in an oxy-fuel CFBC. It was found that temperature, and concentrations of CO2, SO2, and especially H2O are important factors in determining the carbonation/sulfation reactions of CaO.

[1]  Filip Johnsson,et al.  The fate of sulphur during oxy-fuel combustion of lignite , 2009 .

[2]  RajenderKumar Gupta,et al.  Oxy-fuel combustion technology for coal-fired power generation , 2005 .

[3]  John R. Grace,et al.  Simultaneous CO2/SO2 Capture Characteristics of Three Limestones in a Fluidized-Bed Reactor , 2006 .

[4]  B. M. Gibbs,et al.  Pulverized coal combustion in air and in O2/CO2 mixtures with NOx recycle , 2005 .

[5]  Chunbo Wang,et al.  Influence of Water Vapor on the Direct Sulfation of Limestone under Simulated Oxy-fuel Fluidized-Bed Combustion (FBC) Conditions , 2011 .

[6]  V. Manović,et al.  SO2 retention by reactivated CaO-based sorbent from multiple CO2 capture cycles. , 2007, Environmental science & technology.

[7]  J. Grace,et al.  Sequential capture of CO2 and SO2 in a pressurized TGA simulating FBC conditions. , 2007, Environmental science & technology.

[8]  K. Laursen,et al.  Strength development due to long term sulfation and carbonation/sulfation phenomena , 2001 .

[9]  A. Sharma,et al.  Mechanistic prediction of ash deposition in a pilot-scale test facility , 2005 .

[10]  Edward J. Anthony,et al.  Experimental Study of Oxy-Fuel Combustion and Sulfur Capture in a Mini-CFBC , 2007 .

[11]  Edward J. Anthony,et al.  Agglomeration and Fouling in Three Industrial Petroleum Coke-Fired CFBC Boilers Due to Carbonation and Sulfation , 2000 .

[12]  V. Manović,et al.  Sequential SO2/CO2 capture enhanced by steam reactivation of a CaO-based sorbent , 2008 .

[13]  F. Wigley,et al.  Ash deposition of a Spanish anthracite: effects of included and excluded mineral matter , 2002 .

[14]  Eric Croiset,et al.  Combustion characteristics of coal in a mixture of oxygen and recycled flue gas , 2006 .

[15]  C. Sobrino,et al.  Study on ash deposition under oxyfuel combustion of coal/biomass blends , 2010 .

[16]  Yewen Tan,et al.  Numerical investigation of oxy-coal combustion to evaluate burner and combustor design concepts , 2004 .

[17]  Hong Yao,et al.  Ash particle formation during O2/CO2 combustion of pulverized coals , 2007 .

[18]  P. Smirniotis,et al.  Calcium Oxide Doped Sorbents for CO2 Uptake in the Presence of SO2 at High Temperatures , 2009 .

[19]  Chunbo Wang,et al.  Carbonation of fly ash in oxy-fuel CFB combustion , 2008 .

[20]  Vasilije Manovic,et al.  CO2 Carrying Behavior of Calcium Aluminate Pellets under High-Temperature/ High-CO2 Concentration Calcination Conditions , 2010 .

[21]  Ligang Zheng,et al.  Assessment of coal combustion in O2+CO2 by equilibrium calculations , 2003 .

[22]  Yi Li,et al.  Experimental study of ash formation during pulverized coal combustion in O2/CO2 mixtures , 2008 .

[23]  Larry L. Baxter,et al.  Influence of ash deposit chemistry and structure on physical and transport properties , 1996 .

[24]  Mónica Alonso,et al.  Sulfation of CaO Particles in a Carbonation/Calcination Loop to Capture CO2 , 2008 .

[25]  Himanshu Gupta,et al.  Multicyclic Study on the Simultaneous Carbonation and Sulfation of High-Reactivity CaO , 2004 .

[26]  K. Okazaki,et al.  Simultaneous easy CO2 recovery and drastic reduction of SOx and NOx in O2/CO2 coal combustion with heat recirculation☆ , 2003 .

[27]  J. V. Iribarne,et al.  Fouling in a 160 MWe FBC boiler firing coal and petroleum coke , 2001 .

[28]  Christopher R. Shaddix,et al.  Combustion kinetics of coal chars in oxygen-enriched environments , 2006 .

[29]  Vasilije Manovic,et al.  SO2 Retention by CaO-Based Sorbent Spent in CO2 Looping Cycles , 2009 .

[30]  John R. Grace,et al.  Removal of CO2 by Calcium-Based Sorbents in the Presence of SO2 , 2007 .

[31]  B. Leckner,et al.  Deposits on heat transfer tubes during co-combustion of biofuels and sewage sludge , 2006 .

[32]  J. Williamson,et al.  The roles of lime and iron oxide on the formation of ash and deposits in PF combustion , 2002 .

[33]  Chunbo Wang,et al.  The effect of water on the sulphation of limestone , 2010 .

[34]  A. Georgakopoulos,et al.  Ash Deposition in a Pulverized Coal-Fired Power Plant after High-Calcium Lignite Combustion , 2004 .