I am designing a generator for Vapour Absorption System and needed help to understand the process of choosing heat exchanger for ammonia water pair.
Dear kunal kanoi,
In ammonia (BP.-33.340C) VAM as a refrigerant and water (BP1000C ) as a absorber. Heat exchanger used to cool weak solution from generator. It is also heats the strong solution coming from pump, thereby reducing heat to be supplied at generator. In absorber dry ammonia dissolved in cold water and strong ammonia solution is formed. Heat evolved in absorption is removed by circulating cold water through the coil kept in absorber. The highly concentrated ammonia is then pumped by a pump to generator through a heat exchanger. This heat Exchanger
1. May be used cascade type.
2. Plate type heat exchanger
3. Tube and shell type heat exchanger.
But frame plate type heat exchanger is better.
The heat exchangers of the generator rectification system designed as compact plate-fin heat exchangers and the column was filled with stainless steel Pall rings.
Never use copper or aluminum in your heat ex-changer design as it can be easily attacked by ammonia. Shell and tube type may be the best choice for your case.
I would suggest you to go for a single pass vertical shell and tube heat exchanger.
Also with cooling water (Cold Fluid) on the tubeside and ammonia-water mixture on the shell side.
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