Agglomeration of granulated copper smelter slag in oxygen carrier aided combustion
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Typ
Program
Kemiteknik 180 hp (högskoleingenjör)
Publicerad
2023
Författare
Thorpe, Ati
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Oxygen carrier aided combustion (OCAC) is a concept used in fluidized bed boilers. The oxygen carrier used in OCAC functions as an oxygen buffer, which allows for better oxygen distribution which in turn decreases incomplete combustion and the excess air flow need. A promising potential oxygen carrier is granulated copper smelter slag, commonly known as iron sand. However, in unpublished research it’s been observed that granulated copper smelter slag has agglomerated (lumped together) when rapidly heated from its fresh state to around 800 °C during OCAC. As agglomeration could cause the fluidized bed boiler to stop fluidizing (defluidization), investigation seemed prudent. The project aimed to investigate the cause of the agglomeration, and potential solutions. A laboratory scale fluidized bed was used in conjunction with a sweep electron microscope to try to find the cause of agglomeration. The study found that defluidization of granulated copper smelter slag occurred both in the presence and absence of air, at around 650 ºC. In other words, oxidation is unlikely to be the primary cause for defluidization and in turn agglomeration. Additionally, it was found that oxidation of copper smelter slag affected defluidization and higher oxidation levels hindered defluidization. As the oxidation affected defluidization it could be possible to avoid defluidization by slowly heating copper smelter slag. In conclusion additional research on the oxygen free defluidization would be required to understand the underlying cause for the agglomeration of granulated copper smelter slag in OCAC.
Beskrivning
Ämne/nyckelord
granulated copper smelter slag , OCAC , Iron sand , agglomeration , defluidization , fluidized bed