Overview
Condensate system in biomass power plant
Instrumentation for level, flow, temperature and pressure
The condensate system collects, refreshes, heats, de-aerates and pressurizes the condensate, to be used as feed-water for further steam production. The low pressure of around 7 kPa in the condenser has a major influence on the cycle efficiency. The remaining heat in the constant pressure condenser is rejected through the external cooling or further uses in cogeneration. Missing water in the system is topped up by make-up water, fed into the condensate storage tank. To keep conductivity and silica levels in the system at the required low levels, a partial condensate stream is treated by a polishing plant. The feedwater is heated up in the train of feed-water heaters using exploited steam from the turbine. The feedwater is de-aerated to low ppb levels of oxygen. The preheated and de-aerated feed-water is then fed again into the steam generator at pressure levels of around 350 bar.
The condensate has very low conductivity and can be measured by KROHNE OPTIBAR DP flowmeters or OPTISONC 3400 ultrasonic flowmeters. Many levels in the condensate system need to be monitored and controlled. This can be achieved using OPTIFLEX 7200/ 8200 guided radar level meters directly integrated into the storage tanks - or by BM26 bypass level gauges which can incorporate a variety of different technologies such as TDR, FMCW, MLI or limit switches, in redundant configurations if required.