System will work at manual or auto position. All controls have to be done and all provisions have to be marked end so the system be able to work for 24 hours. Persons operating the plant have to be well educated and they have to know the system well.
Assume that a 300 ton/day capacity plant also has pre-refinement passed the test phase…
- The charge taken into the pre-refinement section is heated and the water and products with low boiling ranges in the charge are sent to the top drums. This complex product taken from top drum is sent top re-refinement slop tank. It can be reserved to be utilized as fuel or to be sold to the market, after it has been settled in this tank and the water inside has drained out.
- Gases will be also occurred in the top drum, there is a line to the flare and a valve on it controls the pressure. Waste gases are sent to flare with this valve and it will also keep and provide the pressure of pre-refinement system.
- Products obtained from the deep are sent to vacuum column. Fractionation process is started here.
- It passes through the heating system before going to vacuum column to reach it to the desired separation temperature. Product spilled onto the column with this temperature is separated by the effect of the vacuum concurrently. Vapor flow starts towards the top.
- Firstly, the product obtained from top of the column is taken and re circulated to the top again. (REFLUX). After the top temperature has stabilized, the top product is started to pulling by keeping the temperature constant. The refluxing process is adjusted by allocating a ratio and this ratio is kept constant (reflux amount works cascade with the top temperature) (PLS auto system will do this itself)
- At this stage, MD oil will start to be taken inside and the same back circulation will be processed. When the desired temperature occurs at traction tray, level will be taken to auto cascade position and stabilized by doing the level adjustment.
- HV oil also starts to flow at the same time. We adjust the hot and cold return flows according to the desired product values. When the system is completely finished and starts to operate regularly, then all control systems are sent to auto mode and followed.
- The product remained at the bottom, goes to the slop tanks.
- We help the system to provide the desired product properties by interfering to the set values when needed.