Carbon Footprint Assessment with LCA Methodology
17
8 Other LCA Examples
8.1 LCA of the Metallurgical Sintering Process for Carbon
Footprint Assessment [27]
Previously, LCA is explained in a generalized way of assessing the carbon footprint
for any general system. Let us now discuss the carbon footprint assessment for a
complex process to understand the ground-level reality of the working mechanism
of what we have learned previously. Before that, one should understand a bit about
the sintering process. Sintering is a complex and intensive metallurgical process that
provides the desired feed to iron and steel making operations. One may have some
doubt that why a metallurgical operation is selected here. The main reason is the
GHG contribution of the iron and steel sector. The statistics are huge for the emissions released by these metallurgical operations. Out of all, sintering contributes
to a major proportion of GHG’s. These contributions are due to the coke utilization in it which is added for heating and reducing purposes. It does work well for
the assigned task but unknowingly contributes to emissions. Not only this but also
the coal to coke carbonization also releases additional emissions. Let us see some
statistics for sintering. The emission values released during coke making are not
very significant but still noteworthy. These values were 0.001–1.230 kg/Mt for COx,
0.002–0.120 kg/Mt for SOx, and 0.09–3.173 kg/Mt for NOx (Source: Central Pollution Control Board (CPCB), Govt. of India). Meanwhile, a traditional sinter practice
discharges around 241.53 kg of CO 2 , 22.58 kg of CO, 0.294 kg of NOx, and 0.63 kg
of SOx for per tonne of sinter [47]. Now imagine the emissions released for billions
of tonnes of annual sinter production. To restrict that, a separate study carried out for
utilizing biomass (sawdust and charcoal designated as SD and CH, respectively), that
showed a reduction in those emission values released during conventional sintering.
The upcoming sections will discuss how these modifications helped in the reduction
of emission values. Additionally, LCA will also be used to compare the two to predict
the feasibility of both processes, to follow up on the environmental goals (see Fig. 2).
Goal and Scope: The study here is about the assessment of sintering operation and its
carbon footprint. Also, a comparative assessment of biomass and coke is manifested
regarding the emission profile. Overall, the study outlines a conventional as well as a
modified sintering process. The stage is further divided into four factors for a better
distinction.
The functional unit: The investigatory campaign here revolves around metallurgical
sintering operation. This operation is going to serve as the functional unit here. Also,
there will be an additional modification in the fueling framework of the functional
unit. A comparative functional unit for biomass and coke is illustrated in Fig. 1,
which shows the variation in the fueling framework.
System boundaries: The assessment has been carried out to understand the effectiveness of the fuel substitution in terms of the carbon footprint as well as nitrogen
17
8 Other LCA Examples
8.1 LCA of the Metallurgical Sintering Process for Carbon
Footprint Assessment [27]
Previously, LCA is explained in a generalized way of assessing the carbon footprint
for any general system. Let us now discuss the carbon footprint assessment for a
complex process to understand the ground-level reality of the working mechanism
of what we have learned previously. Before that, one should understand a bit about
the sintering process. Sintering is a complex and intensive metallurgical process that
provides the desired feed to iron and steel making operations. One may have some
doubt that why a metallurgical operation is selected here. The main reason is the
GHG contribution of the iron and steel sector. The statistics are huge for the emissions released by these metallurgical operations. Out of all, sintering contributes
to a major proportion of GHG’s. These contributions are due to the coke utilization in it which is added for heating and reducing purposes. It does work well for
the assigned task but unknowingly contributes to emissions. Not only this but also
the coal to coke carbonization also releases additional emissions. Let us see some
statistics for sintering. The emission values released during coke making are not
very significant but still noteworthy. These values were 0.001–1.230 kg/Mt for COx,
0.002–0.120 kg/Mt for SOx, and 0.09–3.173 kg/Mt for NOx (Source: Central Pollution Control Board (CPCB), Govt. of India). Meanwhile, a traditional sinter practice
discharges around 241.53 kg of CO 2 , 22.58 kg of CO, 0.294 kg of NOx, and 0.63 kg
of SOx for per tonne of sinter [47]. Now imagine the emissions released for billions
of tonnes of annual sinter production. To restrict that, a separate study carried out for
utilizing biomass (sawdust and charcoal designated as SD and CH, respectively), that
showed a reduction in those emission values released during conventional sintering.
The upcoming sections will discuss how these modifications helped in the reduction
of emission values. Additionally, LCA will also be used to compare the two to predict
the feasibility of both processes, to follow up on the environmental goals (see Fig. 2).
Goal and Scope: The study here is about the assessment of sintering operation and its
carbon footprint. Also, a comparative assessment of biomass and coke is manifested
regarding the emission profile. Overall, the study outlines a conventional as well as a
modified sintering process. The stage is further divided into four factors for a better
distinction.
The functional unit: The investigatory campaign here revolves around metallurgical
sintering operation. This operation is going to serve as the functional unit here. Also,
there will be an additional modification in the fueling framework of the functional
unit. A comparative functional unit for biomass and coke is illustrated in Fig. 1,
which shows the variation in the fueling framework.
System boundaries: The assessment has been carried out to understand the effectiveness of the fuel substitution in terms of the carbon footprint as well as nitrogen