We have a Visbreaker furnace with four coils. On each outlet the temperature is monitored (COT) and also on the main transfer line. A year or two after startup, we noticed spurious COT readings, i.e. 30 to 60 degF lower than the transfer line. The instrument department checked using a test...
At our refinery we have an API separator that skims separated oil using slotted pipes. In looking into rotating pipe/drum skimmers, I have seen certain claims for the oil recovered being <10 v/v % or even <5 v/v %water. Oil extracted using the slotted pipes generally has >50 v/v % water, unless...
We upgraded a small vacuum column (26,000 BPSD) a few years ago and changed the overhead from direct contact ejector condensers to shell and tube ejector condeners. We are experiencing severe corrosion problems due to low sour water pH problems (column uses stripping steam). Can we use ahhydrous...
Currently we are preparing to implement a new MPC controller on one of our process plants. Generally, the approach used is where the relationships between manipulated variables (MVs, also called 'handles), controlled variables (CVs, or targets) and disturbance variables (DVs) are defined based...
We have plans to revamp a Sour Water Stripper using 316L stainless steel internals. However, we anticipate that at times there may be high Chloride content in the sour water due to leakage on seawater condensers, of which we have a few. This may be more for a metallurgist, but if anyone has...
We have a vacuum column designed with a three stage overhead (ejector/condenser) system. From inception the pressure obtained in the column was above design (40 mmHgabs compared to design 20 mmHgabs). This was so whether the first stage ejectors were on or not. We had three first stage ejectors...
