Cooling Systems for Steel Plants - Oschatz Plant Construction

Solutions for Steel Works

Iron and steel metallurgy has been a high priority at Oschatz for many years. To ease the burden on the environment and make use of the thermal energy in waste gases, Oschatz has developed systems for cooling the hot, heavily dust-laden, carbon-containing waste gases from iron and steel production plants.

These cooling stacks/systems convert the resultant process heat into steam that can be used industrially. Oschatz serves industrial plants such as

Oxygen steel plants,
Sinter plants,
Coking plants,
Direct-reduction process systems,
Electric Arc Furnaces (EAF)

and as a technological partner also offers competence and experience in the field of research and development.

Waste Gas Cooling Plant Hisarna Process

An example is the Hlsarna process, which was developed as part of the ULCOS project (Ultra-Low Carbon Dioxide [CO₂] Steelmaking). This has the goal of halving the carbon dioxide emissions in steel production.

Oschatz built waste gas cooling sections in connection with the HIsmelt process for the first time in 2005; these have been successfully used in the HIsarna process since 2011.

This forward-looking process combines the preheating and partial pyrolysis of the coal in the reactor, the melting cyclone for melting iron ore and the melting crucible for subsequent reduction of the iron ore and iron extraction.

The consumption of coal is thus reduced, which results in a significant cut in carbon dioxide emissions.

The round design conceived by Oschatz. provides a particular contribution to ensuring maximum efficiency in the production of steel.

Another development serves the optimal detection of primary gases escaping from converters, taking into account the technological design of the lowest part of the cooling stack.

For plants operating with air factors around 0.05 to 0.1 Oschatz has made a significant contribution – in cooperation with well-known steelworks and de-dusting companies -–to the development of skirts that provide the perfect technological match.

Our Portfolio

Waste gas cooling plants à HIsarna (Hisarna) process
Sinter cooler, waste heat boilers for sinter plants
Coke dry quenching systems in coking plants
Cooling stacks for HIsmelt plants

Cooling Plants for Converter Waste Gases Oxygen Steel Plants

Oschatz designs, produces and installs complete converter waste gas cooling systems for waste gases from top and bottom blowing converters converting the generated process heat into steam.

At Oschatz waste gas cooling plants with evaporation cooling, exhaust gases are cooled from approx. 1700 °C to approx. 900 °C. This process heat, converted into steam, can then be used for a wide variety of applications and significantly reduces the primary energy input in oxygen steel plants.

A downstream reservoir makes it possible to ensure a constant flow of gas for burning, providing for further heat recovery without flaring up the gas.

Sinter Cooler for Energy Recovery in Sintering Plants

Tried-and-tested waste heat boilers for energy recovery and the use of heat from exhaust air from sinter coolers form a substantial part of the extensive Oschatz portfolio.

These cool hot sintered material with ambient air.By means of the hood construction above the sinter cooler, the heated cooling air is collected and processed in a waste heat boiler to generate steam and/or hot water.

The installation of an Oschatz waste heat boiler means that the significant heat being produced can be captured, saving large amounts of primary energy.

Waste heat boilers for installation downstream of both sinter belts and sinter coolers with and without auxiliary firing and incorporating hot air recirculation from sinter coolers provide combustion air for auxiliary burners.

If desired, it is also possible to raise the temperature level of the waste heat boiler through the installation of a gas burner. Superheated steam can then be produced for running a steam turbine.

Waste Heat Boilers in Coke Dry Quenching Plants

In recent years, coke dry quenching has developed into an internationally accepted energy recovery process. The fundamental aim of coke dry quenching is to utilize a downstream process to recover energy from the hot cycle.

The CDQ process is implemented in two stages: During the first (preliminary) stage, the heat from red-hot coke is transmitted to inert gas. The second (final) stage is characterised by steam generation.

Cooling Stack for Hismelt Plants

When designing bespoke waste gas cooling stacks, Oschatz can rely on its many years of extensive experience in the field of planning and producing converter cooling stacks.

What is of great importance in the HIsmelt process is the round design of the cooling stacks made by Oschatz. Via lances, unreduced iron ore is fed into the vertical smelting reactor and then reduced in a smelting bath together with coal- that is also injected via lances.

The HAB lance at the head of the smelting reactor is used to blow oxygen-enriched hot air into the process.

The 1,400 °C – 1,500 °C waste gases generated by this process are cooled to 70 °C in the waste gas cooling system, which consists of the waste gas cooling stack and the waste gas cleaning system.

The round design of the cooling stacks offer advantages such as a lower tendency to accretions as well as higher resistance against excessive gas-side pressure, uniform heat transfer and optimum flow conditions.