Download Heat Exchange Experiment: Understanding Unit Operations and Safety and more Lab Reports Chemistry in PDF only on Docsity! Unit Operations: The Heat Exchange Experiment Jason E. Butler Assistant Professor Department of Chemical Engineering The University of Florida January 14, 2005 1 Unit Operations: The Heat Exchange Experiment 2 Figure 1: Configuration of the end caps for the 2-pass and 4-pass shell-and-tube exchanger. The alignment of the caps does not change, but requires liquid feed into different positions. 1 Introduction Currently, the heat exchanger experiment consists of one heat exchanger manufactured by Bosco (??). This small unit is somewhat flexible, allowing us to explore the efficiency of a few different configurations. This includes being able to operate the exchanger in both a 2-pass and 4-pass configuration. With a slight modification to one of the end caps, it would also be feasible to run the exchanger in a 1-pass configuration. Ideally, the surrounding piping could then be changed to allow either counter or co-current flow patterns. Additionally, the students should have the flexibility of running the exchanger at multiple flow rates. The experiments goals are to familiarize the students with the concepts of Reynolds and Nusselt numbers, and how these dimensionless groups fully characterize the heat transport process. The students should, for example, be able to identify a simple correlation which accurately accounts for the oberved log-mean temperature changes of the fluids. This experiment should tie-in with theories of heat transport taught in the second transport course. 2 Setup of Exchanger The exchanger is a shell and tube device, with the possibility of using the system in either a 2-pass or 4-pass configuration. Current plans are to orient the exchanger horizontally and use steam on the shell side to heat water flowing on the tube side. Unit Operations: The Heat Exchange Experiment 5 Figure 4: Flow profile and set-up for the two pass experiment. All connections are made on the “bottom” plate, with the “top” plate input and outputs connected to enable the two-way flow profiles. Unit Operations: The Heat Exchange Experiment 6 Figure 5: Suggested piping for the heat exchanger project. To operate in four-pass mode, valves V1, V3, and V5 must be closed while valves V2 and V4 must be open. To operate in two pass mode, V1, V3, and V5 must be open, while V2 and V4 remain shut. The inlet water valves must be capable of controlling the water flow rate, and it would be ideal to have a flow meter on either the inlet or outlet water lines. If not feasible, the students can measure the flow rates manually, but may need to calibrate the flow rates anyways. Need a way to measure the flow rate of steam, as well. Temperatures must be measured at all inlets and outlets. As drawn, only one thermocouple is indicated for the inlet and outlet lines, requiring two thermocouples. However, a measurement of the temperature as close as possible to the entrance and exit of the exchanger would be best, thus requiring four thermocouples for the tube-side of the exchanger. Valves V1 and V2 could be replaced by a single three-way valve if cheaper; the same is true of valves V2 and V3. However, either on the inlet or outlet, one of the valves must be capable of controlling the flow rate, whereas I am not aware of a three-way metering valve.
