Boiler Feedwater Reservoir
1. Heating Steam Control Valve
Boiler feedwater is degasified in the degasifier on the boiler feedwater reservoir in order to remove harmful gases namely oxygen and carbon dioxide. This process takes place at low pressures (p = 0.1 - 0.4 barg), while the corresponding saturated steam temperature is 102 to 108 °C. The boiler feedwater tank is heated using a steam lance that is placed in the liquid to mix it, and by adding steam from above. The steam is then routed through the heating steam control valve, which must be fitted with noise-reducing internals (Arca Ecotrol® Series 8C and 6N).
2. Boiler Feedwater Control Valve
This control valve is used to regulate the boiler drum level to ensure that there is always enough feedwater in the boiler to generate steam. This boiler feedwater control valve must have an equal-percentage characteristic to compensate for the difference between the characteristic of the boiler feedwater pump and the boiler (Arca Ecotrol® Series 8C and 6H and Series 350 and 380).
3. Deionized Water Control Valve
There are losses in the water-steam circuit as a result of desalination, desludging, and sampling which can be compensated for with deionized water from the water treatment plant. Contaminants that are trapped in the untreated water in either dissolved or solid form are then removed in this plant. This deionized water control valve feeds the deionized water to the boiler feedwater circuit (Arca Ecotrol® Series 8C and 6N).
4. Condensate Control Valve
Condensate that accumulates throughout the entire plant is then fed back to the water-steam circuit using the condensate control valves. Depending on the pressure and temperature of the condensate, evaporation may occur as it expands, and this must be taken into account when selecting the cvs value and valve outlet size (Arca Ecotrol® Series 8C and 6N and Series 350).
5. pH Control Valve
The pH value of the deionized water will be controlled when ion exchangers are added in the water treatment plant. Metering pumps are used primarily for this function, but can also be done using pH control valves (Arca Ecotrol® Series 8C).