Flash Vaporizer Dynamics

and Control


SPECIFICATIONS:   Flash vaporization experiment, showing 20 liter feed tank with ball valve, magnetic drive centrifugal pump, flow control needle valve, glass vaporizer with internal 1000 W heater, glass flash vessel with overflow line, bottoms cooler, overheads condenser, bottoms and overheads sample flasks.  Note also two temperature indicator/controllers and A1000 converter box, liquid and vapor thermocouples, liquid and vapor thermocouples, variable transformer for setting power level.


Packed-Bed NH3 (or CO2) Absorber

Catalytic Hydrolysis of Ethyl Acetate

Power Consumption & Mixing Efficiency in Agitation

Membrane Air Separation

Copper Liquid-Liquid Extraction

Flash Vaporizer Dynamics and Control

Dye Mixer Dynamics and Control

Pump Characteristics Experiment

Wind Power Experiment

Hydrogen peroxide/sodium thiosulfate batch kinetics

  DETAILED OVERVIEW:   In this experiment water, or an ethanol/water mixture, is pumped into a glass vessel containing a 1000 W electrical heater driven by a variable transformer or by a commercial (Omega) PID controller.  The heater effluent flows to a 150 ml glass flash vaporizer.  Vapor from the vaporizer is condensed in a glass condenser, and the liquid bottoms flow to a glass cooler.  Flow rates are measured by collecting and timing.  With an ethanol feed the steady state behavior of the flash vaporizer can be studied.  If the feed is water the apparatus becomes essentially a linear flow heater controlled by a PID controller.  Step response runs can be made using the variable transformer to generate steps in heater power, or by stepwise changes in feed rate.  The students can set the PID gains and the controller set point, and observe sluggish control, good control, oscillatory decay of the error toward zero, or limit cycle oscillations depending on the PID gains. A parameter estimation program can be used to fit step response data.

Overhead and bottoms samples are most conveniently analyzed for ethanol using a gas chromatograph (optional).

Similar control studies can be done using an ethanol/water feed, but the system is no longer linear due to heat of vaporization and vapor/liquid equilibrium effects.

Please contact us at spencer@columbia.edu for more details on the experiment, and for price and delivery.



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