We have a heating medium system where a circulating stream of 20% TEG is heated up to approximately 150°C by the exhaust from a power generator. The piping in the system is carbon steel. The pH is 9.5 to 10 and the oxygen level is approximately 1 mg/l. Leaks in the system can introduce chloride into the heating medium. What kind of maximum chloride content should we allow, before we replace the heating medium, in order to avoid corrosion?
Topic: What is the maximum chloride content allowable before the heating medium needs to be replaced?9 June 2009
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Brian Dalder Forum Moderator 175 Posts
Re: What is the maximum chloride content allowable before the heating medium needs to be replaced?9 June 2009 at 1:29pmI suggest consulting the supplier of your heat transfer medium (TEG) regarding the maximum permissible chloride level for this application. A quick survey of various glycol-based heat transfer media suppliers' literature suggests that chloride levels should be kept below 25 ppm. The pH range you are operating at is good for minimizing corrosion in carbon steel so this is working in your favor. You should also be sure that you are using an inhibited glycol whenever glycols are used in a heat transfer application.