ON LINE CORROSIMETRIC MEAUREMENTS FOR RATIONAL USE OF INHIBITORS IN LOW ENTHALPY GEOTHERMAL PLANTS

Ziel

Use of electrochemical methods to give a real time evaluation of corrosion rates of steels in geothermal loop.
Specially designed apparatus and testing gauges have been used.
The results of this experimentation show the feasibility and the interest of the corrosion rate measurement in geothermal industry by electrochemical way, especially by polarisation resistance.
We observe a good correlation between the real loss of metal and the results of the electrochemical measurement. The effects of the iron sulfide scalling on the corrosion rate can be observed without any alteration of the value.
Comparative tests have been carried out with different fluid speed (0,3 and 3 m/s), different time of exposure (500 h, 1500 h, 2500 h), different alloys and the presence or not of the corrosion inhibitor.
These observation permit us to elaborate a specific corrosion probe capable to give continuous and reliable measurement in hot, salty and sulfide rich fluids. These results are not perturbated by the presence of sulfide scalling.
The monitoring of the study consists in a specific loop (built in derivation of the main geothermal loop) in which the geothermal fluid is maintained at a constant speed.
Electrochemical cells are constituted with rings fitted together and electrically isolated.
The fluid goes through these rings. Their diameters have been calculated in order to obtain flow speeds of 3 m/s and 0.3 m/s.
The tests have been carried out together on carbon steel, stainless steel and titanium.
Two 2500 h monitoring periods have been achieved with and without corrosion inhibitor.
The scanning of the different measuring points have been done by an electrochemical interface,
monitored by a computer which collects the data.
At the end of each period, the electrochemical cells are come apart and weighed. The loss of weight by corrosion permit us to calibrate the electrochemical measurements.

Programm/Programme

ENG-ENDEMO C - Programme (EEC) of demonstration projects and industrial pilot projects (EEC) in the energy field, 1985-1989

Thema/Themen

4.1 - HEATING

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

DEM - Demonstration contracts

Koordinator

Compagnie pour le Développement de la Géothermie et des Énergies Nouvelles

EU-Beitrag

Keine Daten

Adresse

Avenue de Concyr
45064 Orléans
Frankreich

Gesamtkosten