The critical condition of this cooling system required the complete replacement of the technology. In our new project, we took both the current needs and the potential expansion of the company’s operations into account. The installation itself took place during the 10 days of a planned technical break. Unlike its predecessor, the new cooling circuit doesn’t need frequent maintenance, the production flows without interruption or unnecessary costs.
That’s how long it took us to completely replace the system.
That’s the volume of the newly installed water tank.
That’s the length of the steel piping that was replaced.
That’s how much the company will save without outages.
Even though the cooling technology acquired by steel hardening company Schmolz+Bickenbach for its facility in Hustopeče was supposed to last 25 years, its condition became critical after just eight years. The whole system was heavily corroded and requited repeated repairs to piping and the frequent chemical cleaning of furnaces. The problems led to shutdowns every year. Each shutdown not only stopped production, but incurred an expense of up to 500,000 CZK for one cleaning.
This was all caused by poor water management. Pre-treatment was entirely absent, as was biocide treatment or sidestream filtration. The softening filters used lacked capacity and the piping was too small in diameter.
New water treatment
We prepared a completely new project, which took into account the cooling power required, the size of the piping and the flow of the liquid. We also designed a custom accumulation tank. The water is now treated by clarification, filtered, and chemically stabilized so it doesn’t cause corrosion. After these modifications, it perfectly conforms to the requirements of the furnace producer.
During the planned 10 day shutdown, we had to completely disassemble the old system and connect the new one. That included a new tank with a volume of 45,000 litres, 300 metres of steel piping, a management system (MaR) and a monitoring device with breakdown reporting.
We also had to cope with the extremely demanding character of metallurgic operations. If the cooling circuit was breached, the furnaces, working at 1,300 °C, would collapse. This required installing a backup for the pumps that power the cooling system. In the case of a power outage, its role is taken over by a pump powered by liquid nitrogen. If that also fails, mains water is used for cooling instead.
The new system provides stable cooling for the operation. There are no leaks from the piping and no clogging of the exchangers. To save resources, we kept the current quality pumps, which provide sufficient power, including a reserve.
It will be possible to expand the system by adding more furnaces.
New reservoirs can hold 45 cubic metres of cooling waters. From the cold side, pumps send the water to the machines, on the other, the hot water is driven to the cooling tower. The circuit is not pressurized; there is a free flow under the surface. Because the system has to cool furnaces running at 1,200 – 1,300 °C, the flow must never stop. For that reason, the pumps have backupsand to further guard against overheating, a pump powered by liquid nitrogen is installed. If even that fails, an emergency cooling circuit with water from the mains can be used.
The cooling water is treated by sidestream filtration with sweeper jets, everything is gravity-fed and unwanted particles are filtered out through an automated mesh filter. The system performs automated de-slurring of the water from the cooling plant and adds the necessary amount of treated water.
The system is sized for 8 furnaces. It uses two 228 m3/h pumps, even though the real requirement was 160 m3. It was an effective solution to keep current pumps within suitable parameters.
The replacement of the cooling system, which included complete disassemble of the machine room, installation of new piping, connecting the MaR and testing the new equipment, had to be done during a planned ten day shutdown. This was achieved thanks to the precise planning of the job, which was undertaken by a team of 10 experts in 12-hour shifts.
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