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H. Li et al.
Industrial metabolism is a method to describe and analyze the material and energy
flow of an industry, and substance flow analysis (SFA) is a popular method of industrial metabolism. SFA mainly quantifies flows of a certain substance or a certain group
of substances related to specific environmental impacts in a well-defined system, so
that to obtain the methods for improving substance utilization efficiency and reducing
industrial waste discharge and therefore to give guidance on industrial policies and
economic activities [3]. In this paper, a carbon metabolism model for the iron and
steel production was established. This model is for calculating and discussing carbon
emissions at enterprise level in order to lay the foundation for enterprises’ comprehensive emissions reduction plan, as well as for the subsequent implementation of
carbon tax and establishment of carbon trading system [4].
In the integrated process steel production (BF-BOF), carbon enters the steel
production system in the form of fuel and reducing agent, etc. After a series of
transformations, some of the carbon becomes a part of the products or by-products
and the other carbon is discharged into the environment in the form of CO 2 [5]. The
CO 2 from the combustion of fossil fuels or by-product gases is defined as combustion
emission, while the CO 2 from chemical reactions is defined as technical emission.
The sum of the two kinds of emissions is direct emission caused by steel enterprises. Short process steelmaking refers to the process smelting scrap in an electric
arc furnace (EAF) to get rid of high carbon emission processes such as coking,
sintering, and blast furnace ironmaking, etc. [6]. EAF steelmaking only accounts for
about 10% of China’s total steel production [7]. Therefore, EAF steelmaking is the
development direction of reducing carbon emissions in China. In order to understand
and analyze the carbon emission of EAF steelmaking, the carbon metabolism model
of EAF steelmaking process is established in this paper.
Methods
The System Boundary
Figure 1 shows the typical integrated process system boundary in an iron and steel
enterprise, which is composed of raw material input, in-plant material flow and
circulation and product output. For the in-plant part, carbon flows and circulates in
these processes. In this paper, the carbon emissions of nine processes are calculated,
among which the direct emission of CO 2 by carbon metabolism was considered in
other processes except EAF process. As for the EAF process, the carbon emissions
caused by the power consumption which are the main energy consumption should
be considered.
The electric power supply in iron and steel enterprises include purchased electricity and self-powered electricity, and the latter is from captive power plant and
waste energy power generation. In general, waste heat and energy power generation
H. Li et al.
Industrial metabolism is a method to describe and analyze the material and energy
flow of an industry, and substance flow analysis (SFA) is a popular method of industrial metabolism. SFA mainly quantifies flows of a certain substance or a certain group
of substances related to specific environmental impacts in a well-defined system, so
that to obtain the methods for improving substance utilization efficiency and reducing
industrial waste discharge and therefore to give guidance on industrial policies and
economic activities [3]. In this paper, a carbon metabolism model for the iron and
steel production was established. This model is for calculating and discussing carbon
emissions at enterprise level in order to lay the foundation for enterprises’ comprehensive emissions reduction plan, as well as for the subsequent implementation of
carbon tax and establishment of carbon trading system [4].
In the integrated process steel production (BF-BOF), carbon enters the steel
production system in the form of fuel and reducing agent, etc. After a series of
transformations, some of the carbon becomes a part of the products or by-products
and the other carbon is discharged into the environment in the form of CO 2 [5]. The
CO 2 from the combustion of fossil fuels or by-product gases is defined as combustion
emission, while the CO 2 from chemical reactions is defined as technical emission.
The sum of the two kinds of emissions is direct emission caused by steel enterprises. Short process steelmaking refers to the process smelting scrap in an electric
arc furnace (EAF) to get rid of high carbon emission processes such as coking,
sintering, and blast furnace ironmaking, etc. [6]. EAF steelmaking only accounts for
about 10% of China’s total steel production [7]. Therefore, EAF steelmaking is the
development direction of reducing carbon emissions in China. In order to understand
and analyze the carbon emission of EAF steelmaking, the carbon metabolism model
of EAF steelmaking process is established in this paper.
Methods
The System Boundary
Figure 1 shows the typical integrated process system boundary in an iron and steel
enterprise, which is composed of raw material input, in-plant material flow and
circulation and product output. For the in-plant part, carbon flows and circulates in
these processes. In this paper, the carbon emissions of nine processes are calculated,
among which the direct emission of CO 2 by carbon metabolism was considered in
other processes except EAF process. As for the EAF process, the carbon emissions
caused by the power consumption which are the main energy consumption should
be considered.
The electric power supply in iron and steel enterprises include purchased electricity and self-powered electricity, and the latter is from captive power plant and
waste energy power generation. In general, waste heat and energy power generation