150
Z. Tang et al.
carbon reduction, hydrogen is a renewable energy source and has better thermodynamic and kinetic advantages [1], so it is considered to be one of the most potential
and promising reducing agents [2, 3].
So far, metallurgists have done a lot of research on the blast furnace hydrogen
injection, and have achieved remarkable results. From the perspective of research
methods, the research on the blast furnace hydrogen injection is mainly divided
into three aspects: theoretical analysis research [4–7], physical experiment research
[8, 9], and numerical simulation research [10–12]. In terms of theoretical analysis
and research, Kim [4] found that hydrogen injection will increase the slope of the
operating line which includes C and H 2 , but reduce the carbon consumption, based
on the improved RIST operating line; Wang [5] analyzed and proved the feasibility
of hydrogen injection in an oxygen blast furnace by The Conservation of Mass and
Energy; Bernasowski [6] studied the effect of gas mixtures of CO and H 2 in different
proportions on the reduction of iron oxides under equilibrium conditions and the
presence of carbon in the system; Li Bin [7] established the thermodynamic model
of the gas–solid reduction reaction of iron oxides based on the principle of minimum
Gibbs free energy, studied the thermodynamics of the gas–solid reduction of iron
oxides, and a three-dimensional equilibrium diagram of the reduction of iron oxides
with CO and H 2 mixed gas was made.
However, these studies either only consider high temperature or only consider gas
composition, and most of them are carried out under a standard atmospheric pressure
and do not fully consider the working environment of the blast furnace. Therefore,
the promotion of conclusions is somewhat limited. As we all know, the blast furnace
is a high temperature and high-pressure gas–solid countercurrent reactor, so it is
necessary to consider the effects of high temperature, high pressure, and gas composition on the reduction of iron oxides in the blast furnace. Therefore, the scope of
present work is that the reduction of the Wustite in the lower part of the blast furnace
was taken as the research object and the working environment of the blast furnace
as the thermodynamic condition, a thermodynamic model was established based on
the principle of simultaneous equilibrium and the principle of minimum Gibbs free
energy, to study the effect of hydrogen injection at the lower part of the blast furnace
on the reduction process. First, a thermodynamic model that can reflect the carbon
reduction of the lower part of the blast furnace was established; then, based on this
thermodynamic model, the influence of hydrogen injection on the reduction process
was considered.
Establishment of Thermodynamic Model and Conditions
Establishment of Thermodynamic Model
The lower part of the blast furnace is defined as the space below the cohesive zone, the
active coke zone, and the upper tuyere zone. As shown in Fig. 1, the reduction of iron
Z. Tang et al.
carbon reduction, hydrogen is a renewable energy source and has better thermodynamic and kinetic advantages [1], so it is considered to be one of the most potential
and promising reducing agents [2, 3].
So far, metallurgists have done a lot of research on the blast furnace hydrogen
injection, and have achieved remarkable results. From the perspective of research
methods, the research on the blast furnace hydrogen injection is mainly divided
into three aspects: theoretical analysis research [4–7], physical experiment research
[8, 9], and numerical simulation research [10–12]. In terms of theoretical analysis
and research, Kim [4] found that hydrogen injection will increase the slope of the
operating line which includes C and H 2 , but reduce the carbon consumption, based
on the improved RIST operating line; Wang [5] analyzed and proved the feasibility
of hydrogen injection in an oxygen blast furnace by The Conservation of Mass and
Energy; Bernasowski [6] studied the effect of gas mixtures of CO and H 2 in different
proportions on the reduction of iron oxides under equilibrium conditions and the
presence of carbon in the system; Li Bin [7] established the thermodynamic model
of the gas–solid reduction reaction of iron oxides based on the principle of minimum
Gibbs free energy, studied the thermodynamics of the gas–solid reduction of iron
oxides, and a three-dimensional equilibrium diagram of the reduction of iron oxides
with CO and H 2 mixed gas was made.
However, these studies either only consider high temperature or only consider gas
composition, and most of them are carried out under a standard atmospheric pressure
and do not fully consider the working environment of the blast furnace. Therefore,
the promotion of conclusions is somewhat limited. As we all know, the blast furnace
is a high temperature and high-pressure gas–solid countercurrent reactor, so it is
necessary to consider the effects of high temperature, high pressure, and gas composition on the reduction of iron oxides in the blast furnace. Therefore, the scope of
present work is that the reduction of the Wustite in the lower part of the blast furnace
was taken as the research object and the working environment of the blast furnace
as the thermodynamic condition, a thermodynamic model was established based on
the principle of simultaneous equilibrium and the principle of minimum Gibbs free
energy, to study the effect of hydrogen injection at the lower part of the blast furnace
on the reduction process. First, a thermodynamic model that can reflect the carbon
reduction of the lower part of the blast furnace was established; then, based on this
thermodynamic model, the influence of hydrogen injection on the reduction process
was considered.
Establishment of Thermodynamic Model and Conditions
Establishment of Thermodynamic Model
The lower part of the blast furnace is defined as the space below the cohesive zone, the
active coke zone, and the upper tuyere zone. As shown in Fig. 1, the reduction of iron