Steam cycles used as working fluid deionized water additivated with chemicals that will control the pH of the liquid and gaseous phase, dissolved oxygen and incrustations. To control the pH in the liquid phase is usually used phosphates and the vapor phase ammonia (NH3) and its family such as amines, of particular interest in Hygroscopic Cycle. To control the dissolved oxygen is often used hydrazine (N2H4) (increasingly obsolete for several reasons, one of them is that it is carcinogenic). As you can see, all chemicals used in treating water steam cycle are hygroscopic, fully compatible and necessary in this technology.
Another important parameter is the salt content in the vapor, which is not controlled with a chemical treatment itself, but with strict control of water supply and adequate regime of purges. The salt content is controlled indirectly by the measurement of conductivity.
Hygroscopic Cycle leverages the hygroscopic characteristics of additives of the steam cycle, and the salts accompanying the inflow water cycle, recovering thermally and chemically the boiler blowdown. Therefore:
- Hygroscopic Cycle can be commercially applied to all power plants that use a Rankine cycle for any power.
- Most of the equipment and materials are the same as in a conventional Rankine cycle (turbine, boiler, deaerator, pumps, etc.).
- The novelty is the incorporation of an absorber, enthalpy recovery and an internal recirculation of air cooler to get this thermally and chemically boiler blowdown with high concentration of hygroscopic compounds.
- All equipment and materials are commercials and 100% guaranteed by the different manufacturers, so no risk to implement them.