2019 AIChE Annual Meeting
(61b) A Summer Overseas Experience at the Imperial College CO2 Capture Pilot Plant
Author
Five years ago we were presented with an opportunity to participate in summer courses at Imperial College London. The chemical engineering department at Imperial has what could be the only facility of its kind, a pilot-scale (50 kg/kr gas flow) carbon dioxide âcaptureâ faculty. A nitrogen - carbon dioxide mixture is absorbed into a monoethanolamine solution in a packed tower (~7 m height), with steam regeneration in a second tower. The facility is fully-instrumented in a âcatalogâ sense in that different components are chosen (e.g., shell and tube, plate, spiral heat exchangers; vortex, Coriolis, swirl and Venturi flow meters, structured and dumped packing) to provide students with experience in the performance of many different types of components. Even the control systems have, Profibus, Fieldbus, 4-20 mA and some WiFi communications protocols.
Our program needed to occur after Sophomore year (first year is not possible). Students will have had the material and energy balance course, and the first thermodynamics course but no background in fluid flow, heat transfer, mass transfer, phase equilibrium or process control. All essential topics in understanding how the pilot plant operates. A similar problem exists for the companion course, a replacement for our Junior level experimental laboratory, which has a heavy emphasis on data analysis and report-writing. Almost identical academic limitations exist for the students as the normal semester for this lab course is (the 6th) spring of Junior year.
To meet these challenges, a preparation class is held one hr/week during the preceding spring semester. Lecture topics are organized around the Unit Operations, fluid flow, heat transfer, mass transfer, process control. The laboratory experiments are chosen to align with these, (1) fluid flow and measurement, (2) performance of different heat exchangers, (3) gas absorption in a small packed column and (4) Rankine cycle or vapor compression cycle. Modest amounts of homework is given focusing on getting the correct ânumbersâ for say, mass and heat transfer coefficients from simulated experimental and process data. An almost weekly part of the class is taken up discussing the workings of the CO2 absorption/desorption process based on the P&ID diagram â (e.g., what adjustments to flow rates or heat input would reduce the CO2 concentration in the exit gas? What temperatures are needed in the various devices?). The specific names of all of the components (e.g., H100, J101, C100, C400, etc.) â essential when students explore and operate the process â are used from start.
The talk will describe these various challenges (including report writing) and how we have adjusted the preparation course, and time at Imperial to meet them. An example of an attempt at the most efficient way to teach âmass transferâ will be given. While initially the student reports were below what was desired, the Pilot Plant grades from the Imperial College instructor have improved substantially with 2 (of the 4 submitted in the last 2 years â pilot plant groups are 12-14 students) being Aâs and other two just below the A/B cut-off. Likewise, the written reports for the laboratory course (which is graded by ND faculty) have reached a level that matches what our Juniors produce.