Blast Furnace Tuyere Design
Iron is the most widely used metal throughout the world. Primarily it is used in
construction and automobile industries and has important maritime and general industrial
applications in the form of steel. Steel accounts for more than 95% of the metal used
throughout the world. <Ref> The initial stages of steel-making involve the use of blast
furnace, which converts iron ore (raw form) into liquid metal (pure form). It involves a
counter current moving bed chemical reactor in which, coke, iron ore pellets/sinter is
introduced from the top. Iron ore gets reduced to its pure form by passing hot air blast
through the burden. The hot air blast can be combined with an auxiliary fuel and injected into
the furnace through conduits known as Tuyeres. The tuyeres are generally made of cast
copper and are shaped like a tilted frustum.
The tuyeres are exposed to extremely harsh environments with temperatures above
2000⁰C, higher than the melting point of copper. Channels are provided to allow cooling
water to flow throughout the periphery of the tuyere in order to prevent tuyere failure.
Despite several years of research, tuyere failure is very common. It introduces a complex
state of furnace instability, increased downtimes and reduced productivity and therefore,
research is necessary to reduce costs and losses.
There are various causes of tuyere failures. Farkas and Moger (2013) <ref> summarized a
few those reasons as:
1. Direct abrasion and erosion effect of materials (burden and hot gases) in contact with
the tuyere
2. Insufficient cooling of tuyeres – improper tuyere construction,
3. Inadequate number of tuyeres as compared to the size of the blast furnace.
Significant improvement in tuyere life can be obtained by improving the tuyere design. Qie et
al. (2013) performed a flow and heat transfer analysis on tuyere using computational fluid
dynamics (CFD) by assuming the domain to be a simple enclosure around the inner race.
They obtained very high temperature differences across the nose (front end) of the tuyere
which shows that tuyere design plays a very important role in preventing tuyere failure.
Roldan et al. (2005) performed an initial inspection and concluded that damage frequently
happened at the nose of the tuyere. A CFD simulation was performed on the nose part of the
tuyere. They concluded that the gap size between inlet and outlet channel and coating
thickness of the nose plays a major role in determining the liquid penetration. Chen et al.
(2014) performed a parametric analysis on a 3D geometry of tuyere using CFD. They
established that radiation absorption is the greatest heat source of tuyere cooling system.
Sciulli, C. M. (1968) developed an experimental setup to determine the heat transfer rate in
the tuyere. He argued that the obtained heat transfer coefficients were too high to be in the
range of convective heat transfer. He concluded that the heat transfer took place
predominantly in the form of nucleate boiling at the boundary