AUTHOR: Carlos GarzaHYL Technologies, SA de CV

The strategic acquisition by Techint Technologies ofHYL Technologies has many affinities with the

existing activities of the company and extends the range of technologies and services offered for thesteelmaking industry. The HYL process produces directreduced iron (DRI) which is used mainly to produce steelin electric furnaces, together with or as an alternative tosteel scrap.

HISTORYAlthough the use of smelted iron objects can be tracedback as far as about 2000BC, the direct reduction of ironon a commercial industrial scale has only been asuccessful enterprise since the HYL process was firstintroduced in the mid-1950s by the Mexican steelmakerHojalata y Lamina (later Hylsa) who developed a batchprocess for using natural gas to reduce iron ore for use inEAF steelmaking. In reality it is more appropriately apetrochemical rather than a steelmaking technology,since the process involves using the reducing agents froma gas source (natural gas, syngas, coke oven gas, etc) tochemically remove the oxygen from iron ore, thusproducing a purified iron (DRI) for melting in asteelmaking furnace.

Lack of availability of steel scrap made this inventiona necessity for Hylsa and in subsequent years thetechnology continued to be modified and improved. Itwas, however, a technology for Hylsa’s own use and thefirst licences granted to outside companies for using thetechnology were not so much ‘sold’, as ‘purchased’.Although plants in Mexico, Brazil, Venezuela, Iran, Iraqand Indonesia using the original HYL technology werelater licensed, the focus continued to be primarily on Hylsa’s own requirements rather than on the externalmarket.

In the mid-1970s the department in charge of directreduction became the technology division of Hylsa. TheHYL Technology Division, now HYL Technologies,immediately focused on updating its technology to acontinuous shaft furnace process that it had developedearlier, and to commercialise the process worldwide.

The growth of the electric furnace steel industry hassubstantially increased the demand for DRI, a productthat is particularly suitable for the production of high-quality steel, and HYL Technologies is now one of theworld leaders in the design and supply of directreduction plants, with valid patented technologies that have been widely tested. Although the company’shistory has for the most part been dedicated to providing technology solutions for in-plantapplications, HYL has consistently been the innovator inproviding new and improved technologies and solutionswhich then became the standard for others to follow(see Table 1).

Two significant examples are HYL ZR®, a highlyefficient direct reduction process which works withoutthe traditional gas reformer, and the HYTEMP® system,a solution for continually feeding electric furnaces with

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.

HYL direct reduction

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Date Event1957 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.

a

r Table 1 Industry firsts from HYL

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hot DRI, thus increasing the productivity of thesteelworks and reducing power consumption.

HYL ZR PROCESSThe HYL ZR process is a major step in reducing the sizeand improving the efficiency of direct reduction plants.Reducing gases are generated by in-situ reforming in thereduction reactor, feeding natural gas as make-up to thereducing gas circuit and injecting oxygen at the reactorinlet (see Figure 1).

Since all reducing gases are generated in the reductionsection, optimum reduction efficiency is attained, andthus an external reducing gas reformer is not required. Inaddition to lower operating and maintenance costs andhigher DRI quality, the total investment for a ZR plant istypically 10–15% lower when compared to a DR plantwhich includes a reformer.

The overall energy efficiency of the ZR process isoptimised by the integration of partial combustion, pre-reforming and in-situ reforming inside the reactor, as wellas by a reduced requirement for thermal equipment in the plant.

A significant advantage of this process is the wideflexibility for DRI carburisation, which enables controlledcarbon levels in the DRI up to 5.5% to be attained. Thisis possible due to the improved carburising potential ofthe gases inside the reactor which allow for theproduction 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 ofnatural gas and 60–80kWh/t DRI of electricity. The ironore consumption of 1.35–1.40t/t DRI is very low, mainlydue to the high operating pressure of the process.

The impact of eliminating the external gas reformer onplant size is significant. For example, a plant of 1Mt/ycapacity requires only 60% of the area needed by otherprocess plants for the same capacity. For additional

capacity, the area required is also proportionally smaller incomparison since, for example, the same reactor sizewould be used for a 1 million or a 1.5 million t/y facility,and only the other related equipment would increase insize. This also facilitates locating the DR plant adjacent tothe melt shop in existing operations. This plantconfiguration has been successfully operated since 1998with 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 todevelop a 200kt/y capacity Micro-Module, reversing thetendency to ever-increasing module sizes and providingquality DRI capability for small steel mills.

HYL plants can also use conventional steam-naturalgas reforming equipment, which has long characterisedthe process, together with other reducing agents such ashydrogen, gases from coal, petroleum coke and coke-oven gas depending on the particular situation andavailability.

HYTEMP SYSTEMThe HYTEMP system is a pneumatic system for thetransport of hot DRI to the EAF (see Figure 2), usingnitrogen or process gas as the transport gas. It is anenvironmentally friendly process since the DRI is keptenclosed from the time of discharge from the reductionreactor to the discharge into the EAF. The system hasthe flexibility for feeding two EAFs from the samereduction reactor.

At the bottom of the reactor, DRI is discharged to theHYTEMP system where a hot gas flow coming from thegas heater is circulated and used to transport DRI. Toavoid degradation the DRI is transported by pressurebuild-up rather than velocity of the gas. When hot DRIreaches the storage bins on top of the EAF the DRI andgases are separated. The gas is sent to a scrubber to becleaned and cooled, compressed and gas heated forrecycling. Before entering the gas heater, make-up gas isadded to compensate for losses when separating DRIfrom the transport gas.

Hot DRI separated from the transport gas is sent to atransition bin in order to go from the pressure of thetransport system to atmospheric pressure. From thetransition bin DRI goes into the storage bin to be fed intothe EAF by gravity. Hot DRI can also be sent from thereduction reactor to an external cooler when the meltshop is not ready to use or store hot DRI. The externalcooler has the capacity to cool all DRI production.

FUTURE PROSPECTSTechint is now the second-largest international producerof DRI with 12 modules installed in Siderca, Sidor,Matesi and Hylsa and currently produces over 7Mt of

r Fig.1 HYL ZR, Process schematic

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direct reduced iron a year. It is also the fourth largestproducer of electric steel in the world and was one ofthe first users of DRI. This is further confirmation of thestrategic importance of HYL Technologies for Techint.

The worldwide network of Techint Technologies will beof great help in promoting HYL Technologies worldwide.The product of HYL Technologies traditionally involvessupplying a technological package generally comprisingprocess engineering, detailed engineering of certainsections, main components, assembly assistance,including staff training, and the licence to use thetechnology. Tying in with other Techint technologiessuch as electric furnaces, materials handling and qualitysystems for melt shops will make attractive packages for clients looking for the most advanced solutions fortheir operations.

HYL Technologies has already acquired a contract forthe turnkey installation of a 200kt/a Micro-Module plantin Abu Dhabi based on the ZR process. Additionalprojects 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, alsoadding 500kt/y of capacity to their existing installation.

Other projects are in advanced stages of negotiationand 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

r Fig.2 HYL HYTEMP system

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