An effective corrosion inhibitor for H2O/LiBr - absorption refrigeration machines.

Industrial facilities and power plants produce a lot of waste heat. Absorption refrigeration machines can use this heat effectively for cooling. Currently, absorption machines use the working medium combinations water/lithium bromide or ammonia/water. Under the influence of water and salt, for instance lithium bromide, the components of the machines corrode very strongly. Chemicals such as chromates and molybdates can reduce this corrosion processes. The European law forbids the use of chromates since September 2017. However, molybdates only protect iron components of the machines but not copper and other non-ferrous metal parts. Therefore, ILK Dresden started a project in 2015 to establish new inhibitors and strategies to protect the metals of absorption machines working with lithium bromide solutions. New inhibitor combinations were tested successfully. The present paper summarizes the results from one promising inhibitor system which is based on a combination of ternary antimony molybdenum oxides. Applied test methods are presented as well.