Title

THE POTENTIAL FOR CHARCOAL TO REDUCE NET GREENHOUSE GAS EMISSIONS FROM THE AUSTRALIAN STEEL INDUSTRY

THE POTENTIAL FOR CHARCOAL TO REDUCE NET GREENHOUSE GAS EMISSIONS FROM THE AUSTRALIAN STEEL INDUSTRY

Authorship

Mathieson, John G.; Norgate, Terry; Jahanshahi, Sharif; Somerville, Michael A.; Haque, Nawshad; Deev, Alex; Ridgeway, Phillip; Zulli., Paul

Mathieson, John G.

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Norgate, Terry

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Jahanshahi, Sharif

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Somerville, Michael A.

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Haque, Nawshad

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Deev, Alex

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Ridgeway, Phillip

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Zulli., Paul

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DOI

10.5151/2594-357X-22265

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Abstract

Life cycle assessment (LCA) of forestry and pyrolysis has been used to show that charcoal can be produced with net negative CO2e emissions. The scenario described involved sustainably grown forest plantations, the capture and utilisation of bio-oil as a fuel and the production of electricity from the excess combustible gases from pyrolysis. Cradle-to-gate assessment of the use of charcoal in ironmaking and steelmaking has shown that the co-product credits available from the pyrolysis step flow through to enhance net CO2e reductions available from the use of charcoal to between 41% and 75% for the integrated BF-BOF route, and to between 10% and 15% for the EAF mini-mill route, where emissions are dominated by those associated with electricity generation by coal. Of the eight applications investigated, the most significant was found to be the injection of pulverised charcoal into the blast furnace, which is already practiced in mini-BFs in Brazil. Charcoal properties, particularly volatile matter and density, can be adjusted during pyrolysis to optimise performance. Quality criteria have been proposed for each of the applications. R&D and plant trials have indicated that charcoal performance may be superior to that of conventional fossil-based fuels for blast furnace tuyere injection and as a liquid steel recarburiser. Many technical and economic challenges remain, with the greatest being to initiate economic supply of the large quantity of charcoal needed to meet the potential demand of the steel industry.

Life cycle assessment (LCA) of forestry and pyrolysis has been used to show that charcoal can be produced with net negative CO2e emissions. The scenario described involved sustainably grown forest plantations, the capture and utilisation of bio-oil as a fuel and the production of electricity from the excess combustible gases from pyrolysis. Cradle-to-gate assessment of the use of charcoal in ironmaking and steelmaking has shown that the co-product credits available from the pyrolysis step flow through to enhance net CO2e reductions available from the use of charcoal to between 41% and 75% for the integrated BF-BOF route, and to between 10% and 15% for the EAF mini-mill route, where emissions are dominated by those associated with electricity generation by coal. Of the eight applications investigated, the most significant was found to be the injection of pulverised charcoal into the blast furnace, which is already practiced in mini-BFs in Brazil. Charcoal properties, particularly volatile matter and density, can be adjusted during pyrolysis to optimise performance. Quality criteria have been proposed for each of the applications. R&D and plant trials have indicated that charcoal performance may be superior to that of conventional fossil-based fuels for blast furnace tuyere injection and as a liquid steel recarburiser. Many technical and economic challenges remain, with the greatest being to initiate economic supply of the large quantity of charcoal needed to meet the potential demand of the steel industry.

Keywords

LCA; Greenhouse gas emissions; Integrated and EAF steelmaking; Charcoal quality.

LCA; Greenhouse gas emissions; Integrated and EAF steelmaking; Charcoal quality.