Hello, I am new to this site, I was planning on designing a STHE for heating up two process streams which are both a mixture of light hydrocarbons, water, noble gases. hot streams is at 20 atm and cold stream at 21 atm with mean temperature gradient is around 25 K with temperatures roughly in the range 500 K to 330 K in the hot stream and 300 K to 460 K in the cold stream. I was thinking using an U tube (A/BEU) HX because of thermal expansions allowance and consideration of benzene being toxic which doesn't allow the use of other types except AET and BET. I choose U tube because of thermal expansion consideration instead of AET or BET. Since mean temperature gradient is around 25 K so its low but the operating temperatures are high so I choose U-tube
I understand that individual replacement of tubes are difficult due to tube nesting and the consideration that u-tube bundles are harder to clean mechanically. I am just not sure what the industrial practice is when it comes to cleaning toxic hydrocarbons are, is it mechanical or chemical or since they are toxic when fouling occurs is the bundles not cleaned at all. Instead is it replaced?. Also about fouling, I am a bit confused how much of fouling is caused by light hydrocarbons, is it band enough to cause weekly cleaning or annual cleaning?