Background Information:
This customer is a well-known large-scale iron and steel enterprise in northern China, founded in 1958, with a production capacity of 13 million tons in 2016. One of its ironworks produces 3,000 m³/h of blast furnace slag water at 70-80°C, utilizing waste heat for circulating heating.
The customer previously used three rotary nylon brush filters provided by an equipment supplier. After one heating season, the high impurity content and high flow rate in the media resulted in poor filtration performance, causing increased wear on the slag water pump and heat exchanger pump.
Furthermore, the equipment frequently experienced unexpected failures, failing to meet the requirements for continuous operation. The filtration performance was suboptimal, and maintenance costs were considerable, placing a heavy burden on the company.
More seriously, these frequent failures prevented the heating system from providing stable heating. During the harsh winter months when temperatures in the area dropped as low as -35°C, the lives of nearby residents were severely impacted.
To ensure the normal operation of the heating system, the filtration system needed to be modified to ensure continuous slag removal, stable operation, and reduced downtime, thereby improving heating quality.
Chanllanges:
After slag flushing water is flushed from the blast furnace, it flows into a sedimentation tank. However, the tank's small size doesn't allow sufficient time for impurities to fully settle. Consequently, the water entering the downstream circulation system through the secondary water tank and intake well is highly impure (up to 500 ppm).
Traditional filters use a grate to intercept the impurities, then use a rotating nylon brush to scrape off any debris adhering to the grate. The system then backwashes the water regularly to remove the impurities. However, the slag contained in the slag flushing water is irregular in shape, with some slag penetrating the grate. In these cases, the nylon brush not only fails to remove the slag, but actually has the opposite effect, causing it to accumulate on the grate. Consequently, the system must be shut down for inspection and cleaning, which consumes a lot of labor and consumables.
The customer therefore sought a new filter to address these issues. This filter not only effectively removes the slag but also features online self-cleaning, enabling simultaneous cleaning during filtration, thus avoiding downtime and ensuring long-term, stable online operation.
Solution:
After an on-site inspection by LEFILTER filtration experts and several technical discussions with the client's specialists, they recommended a 30-inch self-cleaning filter. This filter handles a large flow rate and features fully automatic, continuous self-cleaning, ensuring seamless, trouble-free operation and easy maintenance.
The LEFILTER automatic backwash filter combines a compact modular design with an automatic flushing system, providing users with a simple, low-maintenance, and environmentally responsible solution. This solution offers several unique advantages, including low energy consumption, no consumables, and zero emissions.
Result: Before and later comparision.
