Q & A > Question Details
I am currently working in a project which includes a decrease in the operating pressure of the stripper in the hydrobon unit (hydrotreatment of naphthas).
Due to this decrease the temperature on top of the column will decrease too and the area of the aereocondenser at the top of the column won't be enough to achieve the desired temperature.
For this reason I am designing a new trim cooler that will use cooling water to achieve the current temperature before the liquid/gas separator. To avoid revaporization downstream the trim cooler will have to cool down both the vapour and the liquid stream.
The inlet current is 7.300 kg/h with liquid phase stream being 6.000 kg/h.
I have simulated it with Aspen EDR and the resultant heat exchanger will have to operate 40% flooded in order to cool the liquid phase stream.
To achieve and control the level of flooding in the trim-cooler two ideas come to my mind: Level control and dam baffles.
This is the first time that I design a trim-cooler but I have checked out the designs of other trimcooler and I have NOT seen any level control instrumentation or dam baffles.
Can anyone familiar with the design of trim coolers comment please?
26/01/2018 A: Jesus Perez, Alfa Laval Packinox, jesus.perez@alfalaval.com
One option to consider might be to look at a different technology in order to complete the duty. You can replace the overheads condenser with a more efficient exchanger capable of condensing the entire load with a smaller LMTD than traditional Air Cooler or S&T overheads. A fully welded plate het exchanger like Alfa Laval's Compabloc or a Wet Surface Air Cooler can do this. If you are set on retaining your main condenser you could look at these technologies for the trim cooler as well.