Q & A > Question Details
Please could someone explain the difference between the following:
1. Internal reflux
2. Circulating reflux
3. Pumparound
10/05/2016 A: Sudhakara Babu Marpudi, Dangote Oil Refinery Company, m_sudhakarababu@yahoo.com
Internal reflux (IR) provides the liquid traffic necessary for the VLE for the section below the total draw off / accumulator / chimney trays. IR is returned to column without any cooling. This helps in returning some of the excess material flashed up (asphaltenes / metals / heavier material from the product below) towards end point correction. Circulating reflux and pump around are names used for the reflux that gets a cooled a bit and enters the column in the area above the draw off tray and helps in controlling the draw off temperatures and draw tray levels (prevents suction loss of the withdrawing pumps). Draw off temperatures control bulk part of the product quality.
19/11/2014 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
Internal reflux is the flow rate inside the column of the liquid from one tray to the tray below. The other two terms are interchangeable and represent the flow rate in the external piping of the liquid drawn the column, through heat exchangers, and back into the column either above or below the draw-off location/elevation.