Based on analysing current blast furnace based steel
manufacturing processes combined with information of
production processes from CO utilising chemical industry,
this study has constructed a process model that acknowledges
the strive for sustainability (Figure 4). The
figure illustrates the constructed process model, where
the area highlighted in grey illustrates the proposed inclusion
of chemical product lines to be integrated into the
proximity of a steel mill. In the constructed model, gases
from blast furnace and basic oxygen furnace, previously
taken to a powerhouse, are now directed to gas treatment.
In reality the gas treatment process is more complicated
and includes e.g. compressing, gas purifications, and a
possible water gas shift reaction.
Should the constructed process model be utilised, from
the perspective of a steel mill, CO gas is valuable as it
can be sold. In addition, emissions trade costs are removed
as CO gas is not burned into CO2. However, there
is also a negative consequence as the electricity, previously
generated from CO gas, must be replaced by purchased,
or separately produced, electricity. In order to
maintain sustainability, the electricity ought to be produced
from non-fossil sources. The technical principles
presented above, form the basis for economic calculations,
discussed in the following chapters