coal selection criteria for industrial pfbc firing project 3.2 - CCSD
coal selection criteria for industrial pfbc firing project 3.2 - CCSD coal selection criteria for industrial pfbc firing project 3.2 - CCSD
“Coal Selection Criteria for Industrial PFBC Firing” Cyclones play a significant role in ensuring the survival of the gas turbine, especially when ceramic filter tubes are absent. The gas exhaust from the cyclones has to be sufficiently clean to minimize the turbine blade erosion. In Osaki, it was found that cyclone plugging was due to the same properties of coal which caused sticky ash material, as described below. Filter blockage is a problem faced by PFBC plants which rely on the ceramic filter for secondary hot gas clean-up prior to the gas turbine inlet. Serious filter blockages could lead to filter breakage and fires. Finer ash particles penetrated into the filter, blocking the pores. This ash was sticky, tending to stick on the filter surface, and could not be removed by cleaning. One coal-related solution to this problem was to use coal ash for maintaining bed inventory. Another method was to use coals with higher Al2O3 and lower SiO2 contents in their ash, which agglomerated to larger ash particles, thus preventing filter blockage. However, the recommended method to overcome filter blockage is to allow larger particles into the filter. These larger fly ash particles do not penetrate into the ceramic filter material, but form a cake on the surface which can be cleaned reliably. Erosion and corrosion of gas turbine blades by coal ash particles are potentially acute problems in PFBC plants especially in plants which do not employ ceramic tube filters but only cyclones for hot gas particulate cleaning. In these plants, erosion and corrosion rates were found to increase substantially when cyclone clogging occurred. The main ash component that is responsible for the erosion is fine quartz particles. Most of the large quartz particles are removed by the cyclone, so that only the fine particles (
“Coal Selection Criteria for Industrial PFBC Firing” Erosion and corrosion of the in-bed heat exchanger tubes also occurred. These problems were not coal-related. A solution for erosion at low temperature is to apply thermal spray coatings to the tubes and at high temperature the tube material should have sufficient erosion and corrosion resistance due to the formation of a hard oxide scale on the surface. Most PFBC plants do not encounter any environmental problems since PFBC is already an environmentally friendly technology. However, they need to obey the stringent emission regulations set by the local EPA. The pollutant reduction methods are primarily related to the operating conditions of the plant, rather than to coal properties. Karita fires coals with sulfur content ≤ 1% and volatile matter ≤ 55%. Page 25
- Page 1 and 2: “Coal Selection Criteria for Indu
- Page 3 and 4: “Coal Selection Criteria for Indu
- Page 5 and 6: LIST OF TABLES “Coal Selection Cr
- Page 7 and 8: “Coal Selection Criteria for Indu
- Page 9 and 10: “Coal Selection Criteria for Indu
- Page 11 and 12: “Coal Selection Criteria for Indu
- Page 13 and 14: “Coal Selection Criteria for Indu
- Page 15 and 16: “Coal Selection Criteria for Indu
- Page 17 and 18: “Coal Selection Criteria for Indu
- Page 19 and 20: “Coal Selection Criteria for Indu
- Page 21 and 22: “Coal Selection Criteria for Indu
- Page 23: 5. CONCLUSIONS “Coal Selection Cr
- Page 27 and 28: 7. REFERENCES “Coal Selection Cri
- Page 29 and 30: “Coal Selection Criteria for Indu
- Page 31: “Coal Selection Criteria for Indu
“Coal Selection Criteria <strong>for</strong> Industrial PFBC Firing”<br />
Erosion and corrosion of the in-bed heat exchanger tubes also occurred. These problems<br />
were not <strong>coal</strong>-related. A solution <strong>for</strong> erosion at low temperature is to apply thermal spray<br />
coatings to the tubes and at high temperature the tube material should have sufficient<br />
erosion and corrosion resistance due to the <strong>for</strong>mation of a hard oxide scale on the surface.<br />
Most PFBC plants do not encounter any environmental problems since PFBC is already<br />
an environmentally friendly technology. However, they need to obey the stringent<br />
emission regulations set by the local EPA. The pollutant reduction methods are primarily<br />
related to the operating conditions of the plant, rather than to <strong>coal</strong> properties. Karita fires<br />
<strong>coal</strong>s with sulfur content ≤ 1% and volatile matter ≤ 55%.<br />
Page 25
Change language