Development of techniques for monitoring gas-phase sodium species formed during coal combustion and gasification

Chadwick, Bruce L.; Ashman, R.A.; Campisi, Anthony; Crofts, G.J.; Godfrey, Peter D.; Griffin, P. G.; Ottrey, A.L.; Morrison, Richard J. S.

doi:10.1016/s0166-5162(96)00039-0

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…). , From the measured release rate profiles, it was possible to model the kinetics of alkali release with a particle model . Using excimer laser-induced fragmentation fluorescence (ELIF), alkali species in the flue gases of different solid fuel combustion systems were measured. − Chadwick et al , used this technique to detect NaCl and NaOH released during the pyrolysis and gasification of coal. Using collinear photofragmentation and atomic absorption spectroscopy (CPFAAS), Sorvajarvi et al detected KCl, KOH, and atomic K released from burning wood particles.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Measurement of Atomic Potassium in Plumes over Burning Solid Fuels Using Infrared-Diode Laser Spectroscopy

et al. 2017

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Solid fuels, such as coal and biomass, comprise a large portion of the current annual world energy supply, roughly equal to the annual oil consumption. During solid fuel combustion, certain species, though they are fairly benign outside of the combustion system, can cause damage in and around the combustion chamber. Alkali release from coal and biomass is known to cause severe problems in solid fuel fired boilers, such as fouling and corrosion of the heat transfer surfaces. In this work, the amount of atomic potassium in the plume of burning single coal, wood, and straw pellets (∼170 mg/piece) was measured using tunable diode laser absorption spectroscopy (TDLAS) of the potassium D1 line at 769.9 nm. The sample pellets were burned in an environment with stable temperature and gas composition provided by a laminar flame burner. More atomic potassium existed in the plume of burning biomass pellets compared with coal pellets, and the two temporal concentration profiles were dissimilar. This was attributed to the difference in the respective combustible components, ash compositions, potassium concentrations, and potassium compound state found in the two fuels. A high proportion of fixed carbon in coal induces potassium release mostly during the char-burnout period. In contrast, biomass has its strongest release during the devolatilization stage since its potassium presents mostly in a water-soluble form. Measurements of atomic potassium concentration during wood pellet gasification were performed in an oxygen deprived hot flue gas environment. The concentration of atomic potassium was found to be halved relative to combustion. The distribution of atomic potassium in the plume at different height above the pellets was also measured and is discussed in brief.

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Section: Introductionmentioning

confidence: 99%

Quantitative Measurement of Atomic Potassium in Plumes over Burning Solid Fuels Using Infrared-Diode Laser Spectroscopy

et al. 2017

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“…From a thermodynamic viewpoint Na can occur as Na-metal, NaOH and NaCl . Recent experiments by Chadwick and co-workers confirmed NaOH in the combustion gas of Australian coals. Using this information possible reaction paths leading to the formation of calcium sulfate and sodium sulfate are (eq 1 − eq 4): …”

Section: Discussionmentioning

confidence: 99%

Temperature-Dependent Fractionation of Particulate Matter and Sulfates from a Hot Flue Gas in Pressurized Pulverized Coal Combustion (PPCC)

Enders¹,

Putnis²,

Albrecht³

2000

Energy Fuels

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The development of new highly efficient combined-cycle power plants is fundamentally linked to the development of new hot flue gas purification systems. Hot flue gas purification systems aim to remove particles and newly formed particulate matter from condensation reactions from the flue gas to prevent any damage to the gas turbine. This study focuses on the characterization of particulate matter which was deposited onto the inner walls of flue gas probes in a 1 MW pilot plant for pressurized pulverized coal combustion under slagging conditions (PPCC). The particulate matter in the flue gas stream originates from incompletely separated fly ash particles and particles formed during condensation processes from the hot flue gas. The phase analysis of the materials was done by high-resolution scanning electron microscopy. The combination of wavelength dispersive electron microprobe with a knowledge of the approximate temperature profile through the flue gas probe allowed the definition of dew points of single crystalline phases under the actual pressure conditions from the hot flue gas in the pilot plant. At high temperatures (>1200°C) the deposits on the inner wall of the flue gas probe are mainly fly ash particles which were deposited in the liquid state. With decreasing temperature, CaSO 4 , Na 2 SO 4 , K 2 Ca 2 (SO 4 ) 3 , and K 3 Na(SO 4 ) 2 condense from the flue gas. The ubiquitous occurrence of crystalline Cr 2 O 3 can be traced to high-temperature refractory materials in the boiler and the subsequent particle separator of the pilot plant. At low temperatures some sulfates may decompose and form highly corrosive pyrosulfate melts. The changes in the phase composition of the deposits correlate well with chemical profiles along the flue gas probe.

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“…Moreover, during the process of combustion and pyrolysis, a large amount of highly corrosive sodium diffuses into the gaseous phase [21], subsequently condensing with aerosols to form haze. Sodium exists in various occurrence forms in coal, but not all forms of sodium will deposit with the ash [22,23]. The culprits were identified as the water-soluble and ion-exchangeable forms of sodium, which easily vaporize during the rapid devolatilization of coal at high temperatures [10].…”

Section: Introductionmentioning

confidence: 99%

Distribution, Occurrence and Enrichment Causes of Sodium in Middle Jurassic Coal from Zhundong Coalfield, Xinjiang

Wang,

Wang

et al. 2024

Minerals

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The coal found in the Zhundong Coalfield is highly suitable for power generation and gasification. However, the high sodium content within the coal leads to severe boiler slagging and contamination. Additionally, sodium disperses into the gaseous phase to form haze, adversely affecting the local atmospheric environment. This study delved into the distribution and occurrence characteristics and enrichment causes of sodium in the coal, employing sequential extraction experiments and testing methods such as XRF, ICP-OES and SEM-EDS. The findings of this research indicate the following: (1) With the increasing burial depth of coal seams, there is a noticeable decrease in the sodium content within the coal. Sodium is primarily distributed within the coal seam, with higher concentrations observed in the upper portions of the same coal seam. Furthermore, the distribution of sodium within the epipedon, overlying rocks and coal seam also exhibits a decreasing trend. (2) Sodium primarily exists in a water-soluble state within coal seams, with H2O-Na accounting for over 70% of its composition. The ion-exchangeable sodium is higher than that in the roof, floor and gangue. Sodium exists in coal seams in both ionic and hydrated ionic forms. It is worth noting that the minerals within coal are not the primary carriers of sodium. (3) These coal seams were formed in a warm and humid shallow lake peat swamp environment, which is not significantly influenced by terrestrial or marine sources. The enrichment of sodium is primarily influenced by later hydrodynamic conditions.

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Development of techniques for monitoring gas-phase sodium species formed during coal combustion and gasification

Cited by 12 publications

References 8 publications

Quantitative Measurement of Atomic Potassium in Plumes over Burning Solid Fuels Using Infrared-Diode Laser Spectroscopy

Quantitative Measurement of Atomic Potassium in Plumes over Burning Solid Fuels Using Infrared-Diode Laser Spectroscopy

Temperature-Dependent Fractionation of Particulate Matter and Sulfates from a Hot Flue Gas in Pressurized Pulverized Coal Combustion (PPCC)

Distribution, Occurrence and Enrichment Causes of Sodium in Middle Jurassic Coal from Zhundong Coalfield, Xinjiang

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