Repeated tube failure in chiller

[dngupta]

Hi everybody

There is frequently tube failure problem in chiller since last 06 months. we are using R-22 in tube side and calcium chloride brine in shell side. this chiller was installed in 2006. We are adding chromate as a corrosion inhibitor in brine and maintaining the chromate 400 to 600 ppm.
We have made some changes in brine flow circuit in 2007.
Earlier circuit
process plant- brine pump-chiller-process plant
Changed Circuit
Chiller- brine tank- brine pump - process plant-chiller

Kindly help me to come out from this problem.

Regards,
DNG

[Tesla]

Are you using cupranicle tubes? Are the replaced tubes failing or old ones? Is it corrosion or errosion? What pressure does the tube and shell side get up to? What is your flow rate and what was it? What is the chiller model and make? Take a high resolution photo then crop a failed section and put on post if you can. Are there any vibration issues? Is there any sign of errosion on the end plate dividers? Are there any sacrificial anodes? Please answer some of these questions so we can help you with more informed answers. All the chillers I have worked on the water is in the tube, Opps except some york chillers.

[Sridhar1312]

Calcium Chloride brine is corrosive.The brine off temperature must be sub zero temperature.
Concentration of Calcium chloride by weight for the temperature has to be maintained and necessary corrosion inhibitor to be used.Probable cause of tube failure must be due to freezing of ice near tubes mainly due to brine not meeting the density requirement causing freezing.
Best thing is to switch over to Mono ethylene glycol solution, here again we have to maintain the concentration for the brine off temperature.

[Magoo]

Are the tube failures due to crushing tubes, or fracture, or pin hole corrossion, or failing at the rolling point to tube sheet.
magoo