Drying of granulated wood ash by flue gas from saw dust and natural gas combustion

Autor: Britt-Marie Steenari, S.L. Holmberg, T. Claesson, M. Abul-Milh
Rok vydání: 2003
Předmět:
Zdroj: Resources, Conservation and Recycling. 38:301-316
ISSN: 0921-3449
DOI: 10.1016/s0921-3449(02)00165-9
Popis: At the district heating plant of Kalmar, Sweden an on-line unit for production of granulated wood ash for nutrient recycling on forest soils is being applied. Currently, the granules are dried by hot air from an oil-fired burner. The objective of this work was to investigate how drying by flue gas affects the hardening of granules, or impacts their chemical composition and properties. Ninety-six granule samples were treated by flue gas from natural gas combustion in a laboratory pilot scale flue gas generator. CO 2 , CO, O 2 , C 3 H 8 and NO concentrations were varied during the experiment. Additionally, some samples were treated by flue gas from combustion of sawdust at the heating plant in Kalmar. Drying by flue gases did not affect the chemical composition of granules, but minor effects were seen in their mineralogy. The carbonate content was slightly higher in granules treated with flue gas from natural gas combustion compared to the granules dried by hot air only, when measured by wet chemical methods. Results from XRD analysis imply that the calcite content is higher and the portlandite and arcanite content slightly less in granules treated with flue gas from sawdust combustion compared to the granules dried by hot air only. The results from this investigation showed no negative effects on ash granule composition or physical structure by the use of a flue as a drying medium.
Databáze: OpenAIRE