Steel Converter Slag as an Oxygen Carrier-Interaction with Sulfur Dioxide
Journal article, 2022

Steel converter slag, also called Linz-Donawitz (LD) slag, has been considered as an oxygen carrier for biofuel chemical looping applications due to its high availability. In addition to its content of iron which contributes to its oxygen-carrying capacity, LD slag also contains a significant amount of calcium. Calcium, however, is known to interact with sulfur, which may affect the usability of LD slag. To get a better understanding of the interaction between sulfur and LD slag, batch scale experiments have been performed using solid and gaseous fuel with or without sulfur dioxide, together with LD slag as an oxygen carrier. The reactivity and sulfur interaction were compared to the benchmark oxygen carrier ilmenite. Sulfur increases the gasification rate of biofuel char and the conversion of CO for both LD slag and ilmenite. However, no effect of sulfur could be seen on the conversion of the model tar species benzene. The increased gasification rate of char was suspected to originate from both surface-active sulfur and gaseous sulfur, increasing the reactivity and oxygen transfer of the oxygen carrier. Sulfur was partly absorbed into the LD slag particles with calcium, forming CaS and/or CaSO4. This, in turn, blocks the catalytic effect of CaO towards the water gas shift reaction. When the SO2 vapor pressure was decreased, the absorbed sulfur was released as SO2. This indicates that sulfur may be released in loop-seals or in the air reactor in a continuous process.

sulfur chemistry

steel converter slag

oxygen carrier

LD slag

chemical looping

biomass

Author

Fredrik Hildor

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Henrik Leion

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Tobias Mattisson

Chalmers, Space, Earth and Environment, Energy Technology

Energies

1996-1073 (ISSN) 19961073 (eISSN)

Vol. 15 16 5922

Utveckling av kemcyklisk förgasning av biomassa för produktion av biobränsle

ÅForsk (Ref.nr20-269), 2020-08-01 -- 2022-12-31.

Subject Categories

Chemical Process Engineering

Bioenergy

Metallurgy and Metallic Materials

DOI

10.3390/en15165922

More information

Latest update

10/25/2023