Most of the domestic small and medium blast furnace soft water cooling uses air coolers. Since the air cooler uses air as a refrigerant and is greatly affected by the season, the temperature of the soft water entering the blast furnace fluctuates with the season.In summer, the maximum temperature of the blast furnace water reaches above 70 ° C, which is much higher than the optimal water supply temperature of 35-40 ° C.The air cooler tube bundle is easy to corrode and leak water. After the "blind death" measures are adopted for the corroded tube bundle, the heat exchange area of the air cooler is reduced, and the temperature of the soft water entering the blast furnace is increased.With the improvement of ironmaking technology and the improvement of the blast furnace utilization factor, the contradiction of insufficient cooling capacity of air coolers has become increasingly prominent, which has seriously affected the safety, high yield and service life of the blast furnace.Plate heat exchanger is a new type and high efficiency heat exchanger with corrugated plate as heat transfer surface, which has the following characteristics:
(1) The heat transfer coefficient is high. As the corrugated plates are turned upside down. A mesh contact is formed in the flow channel, the flow channels cross and the fluid direction changes, and turbulence can be reached when the critical Reynolds number is about 200, which greatly improves the film conductivity and enhances heat transfer.
(2) Flexible assembly, easy disassembly and cleaning.
(3) Small size and small footprint, especially suitable for occasions with limited space. The plate heat exchanger occupies 1/5 to 1/10 of the row-and-tube heat exchanger.
The small and medium blast furnace body cooling soft water system is characterized by large flow and small temperature difference, which determines the structural characteristics of the plate heat exchanger as chunky (larger width and height). It should be made of 316 or 316L stainless steel, with a chunky structure, with two units and one unit, and three plate heat exchangers connected in parallel. This structure not only ensures a good heat exchange effect, but also minimizes pressure loss.