This high-efficiency cooling tower slashes emissions from metallurgical processes
By Gerald Ondrey |
Outotec Oyj (Espoo, Finland; www.outotec.com) has commercialized a new cooling tower that offers increased cooling capacity with significantly lower emissions to air when cooling solutions in metallurgical processes. The new tower can be used in a wide range of process solutions, including zinc plant electrolyte cooling, gypsum and chloride removal by cooling, and gypsum removal for solvent extraction plants.
In the Outotec design (diagram), the warm solution is sprayed into the cooling tower through nozzles near the top, and cooled liquid exits at the bottom. Cooling air is blown into the tower through a fan tunnel at the side, then emerges through horizontal demisters at the top. The main difference between the Outotec and conventional designs is the patented top structure, which enables about twice the air flowrates with smaller emissions, says process metallurgist Tuomas Hirsi. For example, when cooling a Zn electrolyte (2,112 m3/h solution flowrate), from 38°C to 33.5°C, the Outotec tower achieves Zn emissions of 120 kg/yr and sulfuric acid emissions of 370 kg/yr — much lower that the 1,200 kg/yr of Zn and 3,600 kg/yr H2SO4 released from conventional designs, he says.
Outotec towers “dramatically higher cooling…