[addcon]

I work as a process engineer in the chemical industry and we have problem with our heat exchanger. We use steam to heat air to about 135°C (275°F). Today we can only achieve about 115-120°C (239-248 °F). The hot air outlet is finned and has been covered with silica which has been building a small layer over time. The whole heat exchanger is in SS316.

Is there anyone who has any experience with similar problems and  knows the best course of action on how to clean it ?
Is potassium hydroxide, nitric acid etc. suitable ? Or are there other chemical compounds that is better at this specific case ?

[curiouscat]

Where is the silica? Steam side or air side?

[addcon]

The silica is located on the air side.

[curiouscat]

The silica is located on the air side.

You can try a water jet lance if the fins are accessible. Is it a shell & tube?

I was expecting steam side fouling. Precipitated Silica deposits are normally hard to get rid of but on the air side the adhesion may not be too strong.