Interaction between coal and lignin briquettes in co-carbonization

Koskela, Aki; Suopajärvi, Hannu; Fabritius, Timo

doi:10.1016/j.fuel.2022.124823

Cited by 4 publications

(2 citation statements)

References 27 publications

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“…To enable heating, the cylinder was placed inside an Entech model ETF 75/17 V gradient furnace manufactured by Entech AB Ängelholm, Sweden. Koskela et al 25) have previously used this furnace to study interaction between coal and lignin briquettes. The furnace has two separately controllable zones, an upper and lower zone.…”

Section: Reduction Under Load Simulationmentioning

confidence: 99%

Effect of Biocarbon Addition on Metallurgical Properties of Mill Scale-Based Auger Pressing Briquettes

Vitikka,

Iljana,

Heikkilä

et al. 2024

ISIJ Int.

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This work focused on the usage of bio-based and secondary iron and steelmaking raw materials. Auger pressing briquettes, cold-bonded agglomerates made from by-products, mainly mill scale (80%), were successfully tested in industrial-scale blast furnace (BF) trials. The briquettes from industrial production were studied in two different laboratory-scale reduction experiments to compare them to laboratory-made briquettes. A blast furnace simulator (BFS) device was utilized in the simulations mimicking the temperature and gas profiles of an actual BF process. A reduction under load (RUL) device enabled the simulation of the physical load under reducing conditions. To determine how the high-temperature properties of the self-reducing briquettes depend on the amount of biocarbon, a bio-based reducing agent (2-10%) was added to the laboratory-scale briquettes that already contained 5.6% total carbon mainly originating from BF dust. For the recipes studied, a weight loss of about 30% under reducing conditions leads to the disintegration of a briquette under load. Based on the BFS experiments, adding biocarbon to the recipe was profitable in terms of a self-reducing effect up to 6% when the total carbon content was 11%. The RUL experiments showed that the structure of the briquette became extremely plastic with the addition of 4% biocarbon which covers 39% of the total carbon contained in the briquette. This was the upper limit for biocarbon addition due to telescoping and disintegration followed by the formation of fines. The industrial briquettes used in the BF corresponded well to the laboratory-made briquettes in terms of metallurgical properties.

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Section: Reduction Under Load Simulationmentioning

confidence: 99%

Effect of Biocarbon Addition on Metallurgical Properties of Mill Scale-Based Auger Pressing Briquettes

Vitikka,

Iljana,

Heikkilä

et al. 2024

ISIJ Int.

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“…Interactions between coking coal and lignin briquettes has been discussed in co-carbonization. 19) However, Lumadue et al 20) produced briquettes of anthracite fines, lignin, and silicon metal powder, and it was reported that addition of lignin strengthened the very weak briquette of anthracite fines. Full scale performance of this kind of formed coke was successfully tested in cupola furnaces.…”

Section: Preparation Of Formed Coke For Blast Furnace Using Kraft Lig...mentioning

confidence: 99%

Preparation of Formed Coke for Blast Furnace Using Kraft Lignin as a Binder

Nonaka,

Tomono,

Nagashima

et al. 2023

ISIJ Int.

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In the steel industry, the development of a coke production technology that uses low-grade coal is desired. Decarbonization by the use of plant biomass is also an important option. A candidate is formed coke, which is produced by forming non-coking coal using a binder, followed by carbonization. Kraft lignin, by-product in pulp and paper mills is a potential binder because it is an aromatic polymer dissolved from wood. In this study, thermal coal powder was blended with softwood kraft lignin powder at ratios from 0 to 20% and was briquetted by cold-pressing or hot-pressing. Then, the briquette was carbonized at 1 000°C to produce formed coke. To verify whether the formed coke has sufficient strength for use in blast furnace, the product was subject to indirect tensile test. The tensile strength of the carbonized formed coke increased with increasing lignin content; however, a formed coke exceeding the target tensile strength of 5 MPa could not be obtained by cold forming. The briquetting temperature was the determinant strengthening factor of the formed coke. Formed coke produced by hot-pressing at temperatures higher than 150°C with 10% lignin at a pressing pressure of 150 MPa successfully attained the target strength. The tensile strength of the formed coke did not always correspond to the density of the corresponding coke, indicating that carbonized products originating from lignin play a role in strongly binding coal particles. Softwood kraft lignin seems a good binding material for low-grade coal to produce formed coke with high strength.

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