horizontal degasifying heaterReading time:
The degremont® horizontal degasifying heater has been designed to run at pressures equal to or higher than 0.3 bar and to treat cold water flows ranging from 20 m3·h–1 to 600 m3·h–1.
This horizontal appliance comprises three compartments (figure 6) :
- heating compartment (1) positioned below the sprayed water inlet, where water is heated by steam exhausted from the steam scrubber by the baffle (4):
- steam scrubber (2) where the steam is evenly distributed through a system of sprayers.
The water enters into the steam scrubber through calibrated openings (3) due to the natural circulation created by the liquid phase difference in density between the two heating compartments (water + condensed steam) and the steam scrubber (two-phase water and vapour mixture) :
- degasified water storage compartment (10) fed with degasified water overflowing from the steam scrubber.
Water and steam are injected into the degasifying chamber through control valves (7 and 8) that are actuated respectively by the water level in the appliance and by the pressure of the steam phase in the recipient.
This appliance will tolerates quite high flow rate fluctuations (factor of 1 to 5 depending on the application) and produces very low oxygen concentrations in the degasified water (less than or equal to 10 mg·L–1).
De-aerating chambers are used less and less because they do not allow residual O2 to be obtained in relation to the current requirements of boiler or turbine manufacturers. Indeed, this type of equipment has a very low water/steam contact time in the reboiling zone and there is no packing. This technology has therefore been substituted with deaerating towers with packing.