Hippity hoppity, FDR is on its way

April 10, 2023 in Spring Semester

Hello dear readers, EvapoGATOR hopes you all had a great holiday weekend! (Time check: Easter was yesterday, hence the title.) Your favorite IPPD team is still working vigorously to finish optimizing our system before the Final Design Review (FDR) on Tuesday, 4/25.

Here are a few of the big accomplishments our team completed last week:

  • finished an outline for the FDR paper
  • tested system under vacuum
  • completed the evaporation lab with an FSHN graduate student + received feedback
  • tested the evaporator’s natural circulation with a new heat exchanger (HEX)
  • ordered parts for thermocouple tray + manufactured it in the Herbert Wertheim Laboratory for Engineering Excellence (Herbie Lab)
  • made purchases for system labels + new evaporator connections

Our main achievement last week was testing the system under a vacuum, and we are happy to report that the apparatus holds the vacuum pressure well! We discovered a few leaks, found by (1) seeing bubbling from certain parts of the phase separator tank and (2) hearing a loud squealing sound when we increased the pressure in the system by opening the diaphragm valve. To fix these issues, we checked that all gaskets, clamps, and other tri-clover connections were sealed well, and we also bought some new 6″ gaskets for the phase separator tank.

Additionally, EvapoGATOR conducted testing with an FSHN graduate student to understand the usability of the vacuum evaporator and the accompanying lab manual. We fumbled through the testing a bit, and the centrifugal pump actually malfunctioned, so our team decided it was time to find a permanent solution to fix the natural circulation in the evaporator. If you’ll remember, the evaporator HEX was actually the very first part our team purchased, but it was too short and did not have ideal connections, so we decided to get another one with a longer tube + proper connections. However, you will also recall that we’ve been having issues with natural circulation on Evap 2 and might have accidentally messed up the NPT connections by applying Teflon tape incorrectly. Because of this, we decided to use Evap 1 to continue testing the system. To clarify, our team used Evap 2 during graduate testing and changed it out for Evap 1 to continue testing immediately after.

The main differences between Evap 1 and Evap 2 are the HEX configuration (shell-and-tube vs. tube-in-tube) and the connections (tri-clover vs. NPT). First, we believe we were having issues with natural circulation in Evap 2 because of the tube-in-tube layout, and though our group tried to decrease the diameter inside the tube, it still did not fix the problem as much as we wanted (hence the implementation of the centrifugal pump). Next, our liaison specified the need for NPT connections since the evaporator is connected to a steam utility line at 10 psi and 115*C, and it can be dangerous if the steam connection is accidentally disconnected (which is easier to do with tri-clover connections). Due to these risks, our liaison is looking into welding connections onto the tri-clover parts of Evap 1 to address safety concerns. Below are some diagrams showing the difference between HEX configurations of shell-and-tube (like Evap 1) and tube-in-tube (like Evap 2).

Shell and tube HEX diagram
Tube in tube HEX diagram

Now, here are some tasks EvapoGATOR will be working to complete this week:

  • Finish manufacturing/assembling/attaching thermocouple tray
  • Attach labels to the system
  • Finalize drafts for the FDR video + poster
  • Complete welding on Evap 1 tri-clover connections + implement HEX into the system
  • Continue testing to ensure there are no issues
  • Design + manufacture a nameplate using a waterjet
  • Prepare for testing with undergraduate students next week

We are reaching the home stretch, and though EvapoGATOR’s system is pretty much finished assembling and is relatively functional, we’re still trying to iron out some wrinkles. To finish the project, our team needs to add the “new” HEX (Evap 1) into the system, test the vacuum evaporator, add a few extra components, complete undergrad testing, and finalize documentation for FDR. This seems like a lot of work when we only have 2 weeks left until FDR, but our group is sure we will accomplish everything!

Okay, that’s it for now. Thank you for reading, and please enjoy some pictures from this week. See you next time!

Ryan attaching Evap 1 to vacuum evaporator. Notice the tri-clover connections.
Skylar (FSHN grad student) + Emily during graduate student testing.
Boiling/natural circulation in phase separator tank with centrifugal pump.
Skylar attaching the steam utility line to Evap 2 during grad testing of the system.
Emily with the steam line, waiting to empty any rust or corrosion from the line during initial vacuum testing.
Ryan turning on the steam line while Emily waits for the output. Note the PPE worn when handling the steam line.
Skylar emptying out the steam utility line during grad testing. In the FSHN pilot plant, when the steam utility line is turned on, everyone in the lab must yell “steam on!”.
Vacuum pressure gauge, showing that vacuum pressure was ~23 inHg in the system during testing.

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