Iapyx
Industrial
- Oct 7, 2010
- 12
A concept for the room:
We are working with a continuous flow process that, for efficiency purposes, requires very significant (delta T ~350F) heat exchange between two high pressure (1600-1700psig) streams. Each stream is a viscous fluid (85cP cold, ~60cP hot), is in a state of laminar flow and is at a low flow rate (15gpm in 2" sch160 CS pipe). Additionally, too low of velocities present problems with fouling and too high of a pressure drop presents operational problems.
After looking into several heat exchangers (shell/tube, plate, tube/tube, etc) it is apparent that in addition to the excessive pressure drops required to maintain acceptable velocities (>2ft/sec), the required quantity of HEXs to meet the necessary square footage is massive and unrealistic (this is true for exchanging the heat directly between the two fluids or through an intermediary heat transfer fluid, e.g. oil synthetics).
The proposed solution is a set of vessels with internal helical coils and agitation. The coils carry the streams that are transferring the heat and the vessel is filled with a heat transfer fluid, thus immersing the coil. The heat transfer fluid is agitated and constantly recirculates between the two tanks in order to transfer the heat. We are looking into static mixers for inside the coils, but have not reached any decisions on what would be acceptable. Calculations and some small scale lab testing indicate that the coil length is significantly shorter than the length required by any of the HEXs.
Our team has been immersed in the design and review of this section of our process for months now and feel confident about this potential solution. Our concern is that our self immersion might limit some level of objectivity and a failure to see the proverbial forest for the trees, so to speak. Can anyone see a fallacy in the premise of this design? Has anyone had experience with similar challenges or a similar design? Any comments/criticism is appreciated.
We are working with a continuous flow process that, for efficiency purposes, requires very significant (delta T ~350F) heat exchange between two high pressure (1600-1700psig) streams. Each stream is a viscous fluid (85cP cold, ~60cP hot), is in a state of laminar flow and is at a low flow rate (15gpm in 2" sch160 CS pipe). Additionally, too low of velocities present problems with fouling and too high of a pressure drop presents operational problems.
After looking into several heat exchangers (shell/tube, plate, tube/tube, etc) it is apparent that in addition to the excessive pressure drops required to maintain acceptable velocities (>2ft/sec), the required quantity of HEXs to meet the necessary square footage is massive and unrealistic (this is true for exchanging the heat directly between the two fluids or through an intermediary heat transfer fluid, e.g. oil synthetics).
The proposed solution is a set of vessels with internal helical coils and agitation. The coils carry the streams that are transferring the heat and the vessel is filled with a heat transfer fluid, thus immersing the coil. The heat transfer fluid is agitated and constantly recirculates between the two tanks in order to transfer the heat. We are looking into static mixers for inside the coils, but have not reached any decisions on what would be acceptable. Calculations and some small scale lab testing indicate that the coil length is significantly shorter than the length required by any of the HEXs.
Our team has been immersed in the design and review of this section of our process for months now and feel confident about this potential solution. Our concern is that our self immersion might limit some level of objectivity and a failure to see the proverbial forest for the trees, so to speak. Can anyone see a fallacy in the premise of this design? Has anyone had experience with similar challenges or a similar design? Any comments/criticism is appreciated.
