Economic and environmental analyses of biomass torrefaction for injection as pulverized material in blast furnaces.

Abstract

Biomass was the first material used as a fuel by humanity, being replaced by fossil fuels after the industrial revolution. With the growing of environment discursions and the effects of CO2

emissions, biomass has been gaining strength as a potential alterna- tive to fossil fuels, especially for steelmaking, which is responsible for about 5 to 10%

of all CO2 emitted. It is known that biomass, compared to fossil fossils, has a higher volatile content, high moisture and lower calorific value. On the other hand, it has a higher hydrogen content and lower sulfur content (important for the steel industry), in addition it is considered neutral in CO2

emissions. Torrefaction, heating biomass at a

temperature between 200-280°C in an oxygen free atmosphere, is an interesting treat- ment to adapt biomasses for use in the steelmaking processes, mainly in the pulverized

material injection into the blast furnace. PCI is an extremely important process for the production of iron in the blast furnace, due to its ability to reduce coke consumption

and optimize the operation of the reactor. This article comes with the purpose of pre- senting a bibliographic review about PCI technique, torrefaction process, biomasses

and its applicability in the steel industry. In addition, an economic and environmental analysis of the possible use of biomass in steelmaking processes will be presented. Results shows that the use of torrefied biomass in the injection process is interesting, generating savings of 10 dollars and reduction of 264kg in CO2

emissions per ton of

hot metal, with a replacement of 50% of the coal used by biomass.