It is observed that when there is inconsistency of input power resulting in power disturbances either once or more in day, week or month, blast furnace productivity is very adversely affected leading to losses and disrupted schedules.

To mitigate these losses and to tide over such irregularities in input supply the user is heavily dependent on captive DG supply instead running the blast furnace on input supply from the utility provider.

This proves to be costlier alternative as it is a direct drain on profitability. Continuously operating the blast furnace on DG power costs much higher than running it on utility power.

Hi-Rel has pioneered a solution, which helps to efficiently operate the blast furnace on utility supply unaffected by the irregularities of input power, allowing use of DG only when required.

This solution supports any rating of induction motor load, even during input power fluctuations, irrespective of the voltage, whether it is 415 V, 3.3 kV/6.6 kV or 11 kV.

The work-horse of the steel industry and a very vital operation in the steel making process, the blast furnace can operate optimally when the three basic functions of gas flow, reduction and melting processes are finely balanced. The blast furnace is a counter current realtor where solids descend and gases ascend. In this reactor, there are numerous chemical and physical reactions that take place to produce final product, which is hot metal from Iron ore, pellets or sinter.

The blast furnace is a huge steel stack lined with refractory bricks, where iron, ore, coke and limestone are dumped from the top and preheated air is blown with high pressure from the bottom through Tuyere.

The cooked coal, called coke, with a high energy value provides permeability, heat and gases which are required to reduce and melt the iron ore, pellets and sinter. Blast furnace flux is prepared from limestone.

It is melted to become slag, which removes sulfur and other impurities. The raw materials require 6 to 8 hours to descend to the bottom of the furnace where they become final product of liquid slag - impurityes and molten iron - Hot Iron. Large volumes of air are generated from turbo blowers and flow through the cold blast main up to the stoves.

While passing air through the stove heat stored in the refractory brick inside, heats-up air, and generates hot blast. Hot air enters the furnace through Tuyerers. This hot blast ensures that solid mass descends after process, as required.

Liquid iron comes out of hearth bottom of furnace through the skimmer into refractory lined ladles known as torpedo cars. Slag is less dense than iron, it floats on top of the molten iron. It comes out from slag runners and is drained into the slag pit.

As explained, blast furnace operation depends more on hot blast/cold blast. This blast is created by large rating blowers. When there is disturbance in input supply hot blast blower stops, which affects the generation of gas and disturbs counter current realtor. Iron ore, limestone and coke descend faster than required and mix with hot metal gathered in the hearth. This results in generation of waste and loss of production. Secondly it takes hours to clear the wastage from hearth and re-stabilize the blast furnace operation.

With over 25 years of hands-on experience in the field of Industrial Power Electronics, Hi-Rel has designed and developed the UMPS (Uninterruptible Motive Power Supply) especially customised to operate induction motor loads.

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The main benefits of Hi-Rel UMPS are:
1. The unit is sized based on motor FLC and not on motor starting current kick - which is 3x or 6x depending on start up method.
2. This solution is by far more efficient than the conventional UPS as it reduces recurring expenses.
3. Effectively handles input harmonics when it required, maintaining it within the limits.
4. Provides near to unity power factor.
5. No separate motor protections are required. They are built into the UMPS.
6. Soft start and stop of motor reduces mechanical wear and tear of the machines as well as the foundations and, reduces maintenance cost.
7. Cold start of load is possible during power failure.
8. Static switch controls the battery life.
9. Required torque from motor is available at any speed.
10. Maintains motor speed even if there is change in input frequency.

UMPS is particularly recommended when:
??/strong> There is a possibility of explosion
??/strong> Lubricating pump of large turbine
??/strong> Process line chokes up leading to downtime, losses and degradation of quality, and
??/strong> When unplanned shutdown of plant damages the whole batch process and takes long time to restore the production Hi-Rel has successfully installed more than 50 such systems in field for various applications in different industries.