Steel converter slag as an oxygen carrier in a 12 MWth CFB boiler – Ash interaction and material evolution
Journal article, 2019

© 2019 Elsevier Ltd Steel converter slag or LD slag is a byproduct of the basic oxygen steel production process, where raw iron from the blast furnace is converted to steel. LD slag contains mainly calcium and iron compounds and smaller amounts of magnesium, silicon, manganese and vanadium. The iron content, about 17 wt.% of the slag, makes this material a potential oxygen carrier for combustion processes such as Oxygen Carrier Aided Combustion (OCAC) or Chemical Looping Combustion (CLC). This study will present an investigation of the use of LD slag as an oxygen carrier in OCAC at semi-industrial scale. The Chalmers 12 MWth biomass circulating fluidized bed boiler was operated using LD slag as bed material under OCAC conditions. During the operation, bed samples from the boiler were extracted and analyzed with ICP-SFMS, SEM-EDS, XRD and different mechanical tests to analyze chemical and physical changes of the bed material as a function of time. The samples were also investigated in a laboratory fluidized bed reactor to determine the change in reactivity towards common volatile fuel components, i.e. CO, H2, CH4 and C6H6. It was found that LD slag can be utilized as an oxygen carrier in a combustion process for biofuel. However, the reactivity towards syngas, CH4 and C6H6 is reduced as a function of time in the boiler, which is believed to be caused by accumulation of, and interaction with, alkali from the biofuel ash. Sulfur addition may decrease the adverse effects of alkali on combustion efficiency, but not eliminate them completely.

Ash interaction

Steel converter slag

Ash

Oxygen carrier

Chemical looping combustion (CLC)

Recycling

LD slag

Oxygen carrier aided combustion (OCAC)

Author

Fredrik Hildor

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

Tobias Mattisson

Chalmers, Space, Earth and Environment, Energy Technology

Henrik Leion

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

Carl Johan Linderholm

Chalmers, Space, Earth and Environment, Energy Technology

Magnus Rydén

Chalmers, Space, Earth and Environment, Energy Technology

International Journal of Greenhouse Gas Control

1750-5836 (ISSN)

Vol. 88 321-331

Subject Categories

Chemical Process Engineering

Bioenergy

Metallurgy and Metallic Materials

DOI

10.1016/j.ijggc.2019.06.019

More information

Latest update

7/8/2019 2