During the evaporative cooling, liquid droplets are injected into the gas flow by means of spraying lances, serving for the heat reduction of gas during the evaporation process. A reliable operating mode of cooler requires the complete evaporation of droplets at low temperature fluctuations at the cooler outlet. The main features for a safe design of an evaporative cooler are:
- Spraying technology
- Homogeneous gas flow through the evaporation zone
- Control technology
In most of the cases two-component nozzles (water and compressed air) are used for the spraying. As an alternative there is also the possibility to use one-component nozzles. In this case conveying pumps with a definitely higher pressure rise will be necessary.
If necessary, a sorption agent in form of limestone slurry or also sodium hydroxide solution can be injected into the evaporative cooler together with water and compressed air, thus serving as corrosion protection and for the separation of acid crude gas pollutants. In case of use of sorption agents and due to the longer evaporation times of injected liquids, the size of evaporative cooler/spray absorber has to be adapted accordingly.
