pp43-45 MS06 - Millennium Steel

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RAW MATERIALS AND IRONMAKING
HYL direct reduction
With the acquisition by Techint Technologies of HYL Technologies, Techint is now the second
largest international producer of DRI with 12 modules producing more than 7Mt of DRI a year.
The HYL process produces DRI with 94% metallisation with up to 4.5% carbon and can be
directly linked to the EAF for hot charging.
he strategic acquisition by Techint Technologies of
HYL Technologies has many affinities with the
existing activities of the company and extends the
range of technologies and services offered for the
steelmaking industry. The HYL process produces direct
reduced iron (DRI) which is used mainly to produce steel
in electric furnaces, together with or as an alternative to
steel scrap.
T
HISTORY
Although the use of smelted iron objects can be traced
back as far as about 2000BC, the direct reduction of iron
on a commercial industrial scale has only been a
successful enterprise since the HYL process was first
introduced in the mid-1950s by the Mexican steelmaker
Hojalata y Lamina (later Hylsa) who developed a batch
process for using natural gas to reduce iron ore for use in
EAF steelmaking. In reality it is more appropriately a
petrochemical rather than a steelmaking technology,
since the process involves using the reducing agents from
a gas source (natural gas, syngas, coke oven gas, etc) to
chemically remove the oxygen from iron ore, thus
producing a purified iron (DRI) for melting in a
steelmaking furnace.
Lack of availability of steel scrap made this invention
a necessity for Hylsa and in subsequent years the
technology continued to be modified and improved. It
was, however, a technology for Hylsa’s own use and the
first licences granted to outside companies for using the
technology were not so much ‘sold’, as ‘purchased’.
Although plants in Mexico, Brazil, Venezuela, Iran, Iraq
and Indonesia using the original HYL technology were
later licensed, the focus continued to be primarily
on Hylsa’s own requirements rather than on the external
market.
In the mid-1970s the department in charge of direct
reduction became the technology division of Hylsa. The
HYL Technology Division, now HYL Technologies,
immediately focused on updating its technology to a
continuous shaft furnace process that it had developed
earlier, and to commercialise the process worldwide.
The growth of the electric furnace steel industry has
substantially increased the demand for DRI, a product
that is particularly suitable for the production of highquality steel, and HYL Technologies is now one of the
world leaders in the design and supply of direct
reduction plants, with valid patented technologies
that have been widely tested. Although the company’s
history has for the most part been dedicated
to providing technology solutions for in-plant
applications, HYL has consistently been the innovator in
providing new and improved technologies and solutions
which then became the standard for others to follow
(see Table 1).
Two significant examples are HYL ZR®, a highly
efficient direct reduction process which works without
the traditional gas reformer, and the HYTEMP® system,
a solution for continually feeding electric furnaces with
a
Date Event
1957 Start-up of the first commercially successful gas-based direct
reduction plant.
1957 Production of flat products via the EAF, based on the use of DRI.
1958 Batch charging of DRI to the EAF at 600°C.
1965 Use of more than 30% DRI in an EAF charge practice.
1968 Continuous feeding of DRI to the EAF.
1968 Computerised EAF process control system put into use.
1969 Use of foamy slag practices.
1970 Design of pellets for direct reduction.
1970 Production of extra-deep drawing steels in EAF using DRI.
1972 Use of 100% DRI in an EAF charge practice.
1980 Start up of the HYL process continuous shaft furnace in Monterrey.
1986 Implementation of CO2 removal and capture as salable by-product.
1988 Use of cement coating of pellet/lump ores for direct reduction.
1993 HYTEMP pneumatic transportation system and hot DRI feeding to
the EAF.
1994 Production of high carbon DRI (3.0–4.5%).
1997 World’s first dual-discharge (DRI & HBI) plant design put into
operation, Vikram Ispat-Grasim, India.
1998 Startup of first HYL ZR Process plant, Hylsa 4M, Monterrey.
2000 High Carbide Iron™, unique product of the ZR Process.
2003 Development of HYL Micro-Module for requirements of small
steel plants.
r Table 1 Industry firsts from HYL
MILLENNIUM STEEL 2006
AUTHOR: Carlos Garza
HYL Technologies, SA de CV
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r Fig.1 HYL ZR, Process schematic
hot DRI, thus increasing the productivity of the
steelworks and reducing power consumption.
MILLENNIUM STEEL 2006
HYL ZR PROCESS
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The HYL ZR process is a major step in reducing the size
and improving the efficiency of direct reduction plants.
Reducing gases are generated by in-situ reforming in the
reduction reactor, feeding natural gas as make-up to the
reducing gas circuit and injecting oxygen at the reactor
inlet (see Figure 1).
Since all reducing gases are generated in the reduction
section, optimum reduction efficiency is attained, and
thus an external reducing gas reformer is not required. In
addition to lower operating and maintenance costs and
higher DRI quality, the total investment for a ZR plant is
typically 10–15% lower when compared to a DR plant
which includes a reformer.
The overall energy efficiency of the ZR process is
optimised by the integration of partial combustion, prereforming and in-situ reforming inside the reactor, as well
as by a reduced requirement for thermal equipment in
the plant.
A significant advantage of this process is the wide
flexibility for DRI carburisation, which enables controlled
carbon levels in the DRI up to 5.5% to be attained. This
is possible due to the improved carburising potential of
the gases inside the reactor which allow for the
production of iron carbide.
For the production of high quality DRI (94%
metallisation, 4% carbon and hot discharged at 700°C),
the energy consumption is 2.25–2.40Gcal/t DRI of
natural gas and 60–80kWh/t DRI of electricity. The iron
ore consumption of 1.35–1.40t/t DRI is very low, mainly
due to the high operating pressure of the process.
The impact of eliminating the external gas reformer on
plant size is significant. For example, a plant of 1Mt/y
capacity requires only 60% of the area needed by other
process plants for the same capacity. For additional
capacity, the area required is also proportionally smaller in
comparison since, for example, the same reactor size
would be used for a 1 million or a 1.5 million t/y facility,
and only the other related equipment would increase in
size. This also facilitates locating the DR plant adjacent to
the melt shop in existing operations. This plant
configuration has been successfully operated since 1998
with the HYL DR 4M plant and in the 3M5 plant in 2001,
both at the Ternium Hylsa facility in Monterrey.
It was the reformer-less ZR process that allowed HYL to
develop a 200kt/y capacity Micro-Module, reversing the
tendency to ever-increasing module sizes and providing
quality DRI capability for small steel mills.
HYL plants can also use conventional steam-natural
gas reforming equipment, which has long characterised
the process, together with other reducing agents such as
hydrogen, gases from coal, petroleum coke and cokeoven gas depending on the particular situation and
availability.
HYTEMP SYSTEM
The HYTEMP system is a pneumatic system for the
transport of hot DRI to the EAF (see Figure 2), using
nitrogen or process gas as the transport gas. It is an
environmentally friendly process since the DRI is kept
enclosed from the time of discharge from the reduction
reactor to the discharge into the EAF. The system has
the flexibility for feeding two EAFs from the same
reduction reactor.
At the bottom of the reactor, DRI is discharged to the
HYTEMP system where a hot gas flow coming from the
gas heater is circulated and used to transport DRI. To
avoid degradation the DRI is transported by pressure
build-up rather than velocity of the gas. When hot DRI
reaches the storage bins on top of the EAF the DRI and
gases are separated. The gas is sent to a scrubber to be
cleaned and cooled, compressed and gas heated for
recycling. Before entering the gas heater, make-up gas is
added to compensate for losses when separating DRI
from the transport gas.
Hot DRI separated from the transport gas is sent to a
transition bin in order to go from the pressure of the
transport system to atmospheric pressure. From the
transition bin DRI goes into the storage bin to be fed into
the EAF by gravity. Hot DRI can also be sent from the
reduction reactor to an external cooler when the melt
shop is not ready to use or store hot DRI. The external
cooler has the capacity to cool all DRI production.
FUTURE PROSPECTS
Techint is now the second-largest international producer
of DRI with 12 modules installed in Siderca, Sidor,
Matesi and Hylsa and currently produces over 7Mt of
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RAW MATERIALS AND IRONMAKING
r Fig.2 HYL HYTEMP system
HYL Technologies has already acquired a contract for
the turnkey installation of a 200kt/a Micro-Module plant
in Abu Dhabi based on the ZR process. Additional
projects already announced are for the upgrading of
the Mittal Steel Lazaro Cardenas HYL plant in
Mexico, which will reduce that plant’s natural
gas consumption by 20%; as well as a new ZR
Process DR module for Vikram Ispat-Grasim in India, also
adding 500kt/y of capacity to their existing installation.
Other projects are in advanced stages of negotiation
and are expected to commence later this year. MS
Carlos Garza is Director General, HYL Technologies,
SA de CV, Monterrey, Mexico.
CONTACT: carlos.garza@hyltechnologies.com
MILLENNIUM STEEL 2006
direct reduced iron a year. It is also the fourth largest
producer of electric steel in the world and was one of
the first users of DRI. This is further confirmation of the
strategic importance of HYL Technologies for Techint.
The worldwide network of Techint Technologies will be
of great help in promoting HYL Technologies worldwide.
The product of HYL Technologies traditionally involves
supplying a technological package generally comprising
process engineering, detailed engineering of certain
sections, main components, assembly assistance,
including staff training, and the licence to use the
technology. Tying in with other Techint technologies
such as electric furnaces, materials handling and quality
systems for melt shops will make attractive packages
for clients looking for the most advanced solutions for
their operations.
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