Sulfation behavior of limestone under high CO2 concentration in O2/CO2 coal combustion

Liu, H; Katagiri, Shiro; Kaneko, Udai; Okazaki, Ken

doi:10.1016/s0016-2361(99)00212-4

Cited by 130 publications

(117 citation statements)

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“…Based on laboratory-scale studies [17,18] and experiences with pressurized combustion, direct sulfation can be very efficient, leading to better limestone utilization, and temperature strongly influences the reaction rate of direct sulfation. Avoiding calcination would also reduce the related energy losses and deposit formation due to recarbonation.…”

Section: Boiler Calculationsmentioning

confidence: 99%

Near Zero CO₂ Emissions in Coal Firing with Oxy‐Fuel Circulating Fluidized Bed Boiler

et al. 2009

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Carbon capture and storage is a concept to reduce greenhouse gas emissions of energy production from fossil fuels. In oxy-fuel combustion, the fuel is burned in a mixture of oxygen and recycled flue gas. This generates CO 2 -rich flue gas from which the CO 2 is easily separated and compressed. Foster Wheeler Power Group is developing the existing design tools and process models of air-fired circulating fluidized bed boilers to implement specific features of oxycombustion. The validation data is produced from bench-scale and pilot-scale experiments at the VTT, Technical Research Centre of Finland. A three-dimensional circulating fluidized bed (CFB) furnace model is developed and applied by Lappeenranta University of Technology for predicting the effects of oxycombustion in full scale units. This paper presents concept studies and initial 3D modeling results based on a 460 MW e supercritical CFB power plant at Lagisza, and pilot-scale studies with flue gas recirculation demonstrating real oxygen combustion conditions.

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Section: Boiler Calculationsmentioning

confidence: 99%

Near Zero CO₂ Emissions in Coal Firing with Oxy‐Fuel Circulating Fluidized Bed Boiler

et al. 2009

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“…The results listed in Table 4 indicate that in the presence of CO, , there is no strong increase in the sulfation rate with temperature over the range of 750°C to 850°C and the sulfation process appears to be retarded by the presence of CO, . In this respect, extended or long-term sulfation appears to be different from short-term sulfation since it is known that in PFBC environments for instance, where CaCO, i s stable, short-term sulfation is enhanced (Hajaligol et al, 1988;Snow e t al., 1998;Liu et al, 2000;Zhong, 1995;lisa et al, 1991). lisa et al (1 991) has also found a difference between direct sulfation of CaCO, and simultaneous sulfation and recarbonation with sulfation being slower in the latter case.…”

Section: Sulfation-carbonation Experimentsmentioning

confidence: 99%

Strength development due to long term sulfation and carbonation/sulfation phenomena

2001

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124irculating fluidized bed combustion (CFBC) boilers burn high-sulfur fuels such as petroleum coke and high-sulfur coal, while meeting C stringent SO, emission standards by feeding limestone to the boiler. At atmospheric conditions, the limestone first calcines and then sulfates in a process that can be described in terms of a two-step global reaction scheme:(1) CaC03 = CaO + CO,For pressurized fluidized bed combustion (PFBC), where the pressure is typically 1 to 2 MPa (Alaverez-Cuenca and Anthony, 1995) the sulfation process for calcitic limestones can be described by means of the following global reaction:Sulfation (or conversion levels) of the spent sorbent leaving the CFBC is typically limited to 30% to 50%. This incomplete conversion is due to the greater molar volume of CaSO, compared to that of both CaCO, and CaO (46 mL/mol, compared with 37 and 17 mL/mol, respectively (Weast, 1980). The sulfate product forms a dense sulfate shell, which blocks off the centre of the particle, leaving a significant amount of Ca in the sorbent-derived particle unconverted (Anthony and Cranatstein, 2001). This type of reaction is commonly referred to as the core-shell or unreacted core model. Although, limestones are in fact capable of sulfating in at least three different modes (see Figure 1): via the core-shell pattern as noted above; via a network of cracks and macropores in the sorbent; and homogeneously (Laursen e t al., 2000).Most limestones show some combination of these patterns, although the core-shell arrangement seems more common for larger sized particles (probably > 0.1 mm). Nonetheless, the universal experience from FBC boilers is that sorbent conversions are well below quantitative values.Two major operational problems are often attributed to the addition of limestone to FBC: bed agglomeration and fouling. Traditionally, CFBC boilers firing high sulfur, low ash fuels can produce deposits consisting of almost pure CaSO, . Test work has shown that if sorbents or bed materials are sulfated for long times (several days or more), they develop compositions similar to those deposits. Sulfation increases with temperature from 650°C to 9OO0C, and strength increases continuously in the temperature range of 650°C to 950°C. When sulfation occurs under conditions where CaCO, is stable, the overall strength of the deposit increases but the degree of sulfation diminishes. Finally, this work suggests that pellet tests using crushed and calcined sorbents can give misleading information and should be used with caution to study the phenomena described here. Les

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“…[9][10][11][12][13][14][15][16][17][18] However, few works analyse the sulphation at oxy-fuel combustion conditions [19][20][21][22] and the major are related to non-calcining conditions. These studies found that the most important factors affecting to sulphur retention with Ca-based sorbents were temperature, CO 2 concentration, particle size and SO 2 concentration.…”

Section: Introductionmentioning

confidence: 99%

Calcium-based sorbents behaviour during sulphation at oxy-fuel fluidised bed combustion conditions

Garcı́a-Labiano

Rufas

Diego

et al. 2011

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Sulfation behavior of limestone under high CO2 concentration in O2/CO2 coal combustion

Cited by 130 publications

References 14 publications

Near Zero CO₂ Emissions in Coal Firing with Oxy‐Fuel Circulating Fluidized Bed Boiler

Near Zero CO₂ Emissions in Coal Firing with Oxy‐Fuel Circulating Fluidized Bed Boiler

Strength development due to long term sulfation and carbonation/sulfation phenomena

Calcium-based sorbents behaviour during sulphation at oxy-fuel fluidised bed combustion conditions

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Sulfation behavior of limestone under high CO2 concentration in O2/CO2 coal combustion

Cited by 130 publications

References 14 publications

Near Zero CO2 Emissions in Coal Firing with Oxy‐Fuel Circulating Fluidized Bed Boiler

Near Zero CO2 Emissions in Coal Firing with Oxy‐Fuel Circulating Fluidized Bed Boiler

Strength development due to long term sulfation and carbonation/sulfation phenomena

Calcium-based sorbents behaviour during sulphation at oxy-fuel fluidised bed combustion conditions

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Near Zero CO₂ Emissions in Coal Firing with Oxy‐Fuel Circulating Fluidized Bed Boiler

Near Zero CO₂ Emissions in Coal Firing with Oxy‐Fuel Circulating Fluidized Bed Boiler