Combined Steady-State and Dynamic Heat Exchanger Experiment

Authors

  • William Luyben Lehigh University
  • Kemal Tuzla Lehigh University
  • Paul Bader Lehigh University

Abstract

This paper describes a heat-transfer experiment that combines steady- state analysis and dynamic control. A process-water stream is circulated through two tube-in-shell heat exchangers in series. In the first, the process water is heated by steam. In the second, it is cooled by cooling water. The equipment is pilot-plant size: heat-transfer areas of 0.542 and 2.96 m2 and process-water flowrates up to 65 kg/min. The steady-state analysis involves checking energy balances around both hot and cold sides of both heat exchangers after measurements of flowrates, temperatures and pressures have been made. Redundant temperature measurements that do not give exactly the same values require the students to consider data reconciliation methods to ensure theoretically consistent energy balances. Overall heat-transfer coefficients are calculated for both heat exchangers over a range of process-water flowrates. Wilson plots are constructed to determine inside film coefficients, which are compared with predictions of applicable correlations. The dynamic analysis involves step and relay-feedback tests to determine experimental dynamic information for the system. There are two temperature controllers. The first controls the temperature of the process water leaving the heater by manipulating the steam flowrate. The second controls the temperature of the process water leaving the cooler by manipulating the cooling-water flowrate. The dynamic performances of various controller tuning methods are evaluated. Experimental dynamics are compared with dynamic simulations using Aspen Dynamics.

Author Biographies

William Luyben, Lehigh University

William Luyben is a professor of chemical engineering at Lehigh University. He received his B.S. from Penn State and his Ph.D. from the University of Delaware. He teaches Unit Operations Laboratory, Process Control, and Plant Design courses. His research interests include process design and control, distillation, and energy processes.

Kemal Tuzla, Lehigh University

Kemal Tuzla is a professor of practice and associate chair in the Department of Chemical Engineering at Lehigh University. He received his B.S. and Ph.D. from the Technical University of Istanbul. He teaches Unit Operations Laboratory, Fluid Mechanics, and Heat Transfer courses. His research interests include heat transfer in two-phase flows and thermal energy storage.

Paul Bader, Lehigh University

Paul Bader is senior electronics technician in the Department of Chemical Engineering at Lehigh University. His special interest is the unit operations experiments. In the present work he designed and implemented the control loop for the heat exchanger experiment.

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Published

2009-01-01

Issue

Vol. 43 No. 1 (2009): Winter 2009

Section

Manuscripts