Monitoring the dissolved oxygen to avoid corrosion
Continuous measurement of trace levels (ppb) of dissolved oxygen in steam turbine power plants
Oxygen should only be present in trace quantities (ppb) as it can result in corrosion damage to the components of the steam cycle. To minimize corrosion under alkaline operating conditions, mechanical de-aeration and chemical scavenger additives are used to remove the dissolved oxygen (DO).
Prevent corrosion through online measurement of DO
The DO is measured at the outlet of the condensate pump and degassing plant, the inlet of the economizer or the boiler feed vessel. You can remove DO in two steps:
Mechanically: the boiler feed water is heated to the boiling temperature and sprayed with steam to remove all dissolved gases
Chemically: Hydrazine (N2H4) together with oxygen reacts to nitrogen gas and water. Because Hydrazine is carcinogen, you can use sodium sulfite (Na2SO3) to eliminate the remaining oxygen.
User-friendly monitoring of DO
The Memosens technology for oxygen sensors combined with our Liquiline transmitter allows for reliable lab calibration, easy maintenance and minimal downtime of the measurement point.
Hitachi Power Europe GmbH (HPE), a subsidiary of Hitachi, Ltd., designs and constructs fossil-fired power plants. The plant constructor also supplies key components such as utility steam generators, environmental engineering equipment, turbines and pulverizers. Including subsidiaries, approx. 2000 staff is on the company's payroll (as of May 2013).