May 2007 - SIMA

TENOVA HYL CONTINUES EMPHASIS ON ENVIRONMENTAL IRON &
STEEL MAKING WITH ENERGIRON TECHNOLOGY
The first industrial scale direct reduction plant back
in the mid 1950’s was a success on a number of
fronts for HYL. The purpose of providing a quality
pure iron feedstock for electric furnace steel
making was achieved, and step by step a growing
use and acceptance developed for the product,
which led to today’s burgeoning DRI industry
worldwide.
When the 1M Hylsa DR plant in Monterrey, Mexico
was put into operation, the environment was not
a major consideration. The 1950’s was an era of
increased industrialization worldwide following
WWII and little attention was paid at the time to
the ecological effects of industrial growth. The
plant consumed over 4 times the natural gas that
today’s process requires, and since it was a batch
process in open retorts, particulate matter and
gaseous pollution were obvious side-effects of the
technology.
Fortunately, those days have long passed and
today’s technology from Tenova HYL is green and
streamlined. The process is now being marketed
and developed jointly with Danieli & C. under the
new Energiron trademark. Not only is the process
itself the most environmentally friendly, but new
collateral technologies such as the HYL HYTEMP
System have made steel making more efficient
and clean by transporting the DRI hot in a fully
enclosed pneumatic system to modern electric
furnaces. An added advantage of these
technologies is that they are also more efficient
and more cost-effective than ever.
Reducing Gases
In an Energiron plant the reducing gas is produced
in two ways: in an external steam reformer, and/
or directly in the shaft reactor by means of “in
situ reforming” reactions.
The ratio between reforming and “in situ
reforming” can be varied to balance production
Thomas Scarnati
Manager- Marketing & Sales
HYL Technologies, SA.De C.V, Mexico
and investment costs exigencies. The Energiron
scheme can be based on 100% external reforming
to 100% “in-situ” reforming (ZR) or any
combination (small reformer + oxygen injection).
This is a unique characteristic of the Energiron
process flexibility. The most adequate scheme will
depend on the local cost structure of energy and
raw materials. As an example, the scheme with
external reformer consumes more gas, but the
power is minimized, while the ZR scheme minimizes
the natural gas consumption but requires more
power (electricity + oxygen). Also, the product
quality has to be considered: the scheme with
100% external reforming produces DRI with up to
2.4% carbon or up to 3.5% carbon if there is some
oxygen injection, while the ZR produces DRI with
= 4% carbon. The most adequate scheme must
be selected based upon the production cost
analysis up to liquid steel, to consider all factors.
Potential Pollution Sources
Direct reduction is based on the chemical
conversion of iron oxides to metallic iron and iron
carbide by the action of reducing and
carburization agents. To accomplish this, different
sources of reducing/carburization agents can be
used, such as natural gas, coal, fuel oil, and coke
oven gas. As with all industrial processes, there
are wastes and by-products which must be dealt
with.
The potential sources of pollution in a DR plant
can come from several distinct areas, which are
carefully monitored. In recent years it has become
critical for some technologies to incorporate the
means for minimizing or eliminating pollutants in
order for client companies to comply with strict
environmental regulations. Polluting wastes from
direct reduction plants, regardless of the
technology used, can be mainly dust, SO x , NO x
and suspended solids in water effluents.
MAY-2007/33