The blast furnace of a steel metallurgy enterprise features an internal molten iron bath at high temperatures, encased in an outer shell made of the same metal. To prevent the shell from melting, refractory bricks are placed adjacent to the iron bath, reducing heat transfer to the shell, increasing resistance, and expanding the temperature difference. Additionally, within the metallic shell, a circulating water system, known as a water-cooled wall, is installed. This system circulates low-temperature water, which carries away the heat.
A decade ago, as closed-loop cooling towers were not widely recognized, open-loop cooling towers were used for cooling water-cooled walls. After use, it was found that there were insurmountable defects.
Firstly, there's the issue of scaling. As the circulating water cools and降温 through evaporation in open towers and ponds, the scaling ions in the water do not脱离 and are continuously concentrated. Eventually, they exceed the saturation point, crystallizing and precipitating throughout the system, particularly within the water-cooled walls. The scaling on the inner walls thickens over time, severely affecting heat transfer and causing the blast furnace shell temperature to rise continuously. This can lead to the shell becoming soft or even developing cracks. To address this, the metallurgical system uses demineralized water and pure water as the circulating medium, but no matter how clean the treatment, it will never reach 0%. As time goes on, the accumulated scaling ions will still exceed the saturation concentration.
Secondly, impurity issues, such as the tower and pond, require adequate contact and heat exchange with the air. However, despite various impurities being filtered through multiple layers, some will still enter the circulation system, leading to blockages and severe consequences.
Again, the algae issue in large ponds ensures water buffer, enhancing safety, but also leads to an increase in stagnant water, slow water flow, excessive algae growth, which is one of the causes of blockage.
Next, the issue of water waste includes: increased evaporation, frequent discharge, leakage from open towers, and water loss from pools, all contributing to higher operational costs.
Now, with the continuous maturation of the design and manufacturing technology for closed cooling towers, also known as evaporative air coolers, the standard configuration for blast furnace cooling has been changed to evaporative air coolers, thus eliminating the aforementioned issues and also reducing operational costs.
Its advantages include:
1. No Evaporation: Only temperature reduction, no evaporation or consumption; the circulating medium is completely isolated from the external air, with no contact at all. This eliminates the evaporation and consumption of the medium and the entry of impurities, ensuring the stability of the internal medium composition.
2. Non-scaling: Due to no evaporation, the concentration of scaling ions such as calcium, magnesium, and sulfate in the medium remains unchanged, thus scaling does not occur.
3. Easy Maintenance: All coils are fully visible for easy maintenance and inspection.
4. The equipment features four-sided air intake with low wind resistance, resulting in reduced fan power.
