In my previous post "
Some Updates", I mentioned about Process Plant - Heat Recovery View. The plate heat exchanger that has been thoroughly cleaned via "cleaning in place"
(CIP) could not produced the desired output temperature (but we got the flow rate). I blamed the
RTD for the output temperature not correct. Although the
RTD has been serviced, it still shows the same reading.
Today, we realized what was wrong with the plate heat exchanger (or cleaning program). We only conducted
(CIP) for one side only (cold oil 1) i.e. the side which we assumed dirty, contained scale and fouling. The other side (hot oil 2) which we thought was clean (free from scale and fouling) was not cleaned with hot caustic (main ingredient for
CIP). We found out from the newly installed vortex flow meter that the 'hot oil 2' side flow rate is low i.e. about only 54m3/hr. The 'cold oil 1' flow rate can reached up to 105 m3/hr. This shows that the 'hot oil 2' side in the plate heat exchanger is partially blocked with probably scale and fouling. The heat transfer is therefore not efficient and effective. The 'cold oil 1' temperature should reached 240oC from 105oC. However, it only managed to reached 210oC which is not sufficient for the process.
Now that we know the problem, we are doing CIP for the 'hot oil 2' side. After 6 hours of CIP, the flow rate has became 76m3/hr which shows some sign of improvement. We'll circulate the hot caustic until the flow rate reaches at least 90m3/hr. I'm glad that we learned and experienced this. At least our understanding and comprehension, tricks and technique of handling the plate heat exchanger improved. Thanks to one of my supervisor who informed us about the slow flow rate of 'hot oil 2' which as a result could not heat up the 'cold oil 1'.
I hope this post provide some valuable infos for you. If you're confused or do not understand what I'm discussing here, feel free to ask.