Overview
External cooling in hard coal and lignite-fired power plants
Hygienic and efficient cooling
The cooling towers must provide sufficient cooling to maintain low pressure levels in the condenser. The cooling towers use cooling by evaporation of some of the water. The collected cooled water falls to the base of the tower and is then recirculated to the condenser. The evaporated water must be replaced with make-up water. The level of the collected water in the cooling tower is controlled by adjusting the flow of blowdown water. Sufficient disinfection must be added as necessary for hygienic reasons, and to avoid fouling.
The cooling water pipes are large in diameter and circulate a vast amount of water to the cooling tower. Ultrasonic flow meters - either OPTISONIC 3400 Inline or OPTISONIC 6300 clamp-on - are the preferred and simplest choice for this application. The cooling tower basin is the buffer for the cooling water circuit. Level measurement here takes place in a high humidity and wet environment. The IP 67 OPTIFLEX 2200 TDR level meter with a remote converter offers a suitable solution. OPTISONIC 3400, OPTISONIC 6300, OPTIFLUX 1000, OPTIFLUX 2000 are the ultrasonic and electromagnetic flowmeters often used for the measurement of blowdown and make-up water in these cooling systems.
OPTISYS CL is a sophisticated system to accurately measure the chlorine content of the cooling water: chlorine is typically used as a biocide. The instrument incorporates both pH and temperature measurements, for proper calculation of the chlorine level. The system can be used for automatic chlorine dosing control, in compliance with legislative requirements, and also saves biocide consumption.