Material and Energy Balances in a Reactor with Heat Exchange
This Demonstration calculates material and energy balances for a reactor with heat transfer. The reaction is acetylene () hydrogenation to ethylene (), where is hydrogen. The feed rate of is fixed at 100 mol/h; use sliders to change the feed rates of and an inert (). Use either the extent of reaction or the outlet temperature to change the conversion of . Select "extent of reaction" to set the extent of reaction and heat removal rate with sliders to change the outlet temperature. Select "outlet temperature" to change the outlet temperature and heat removal rate to determine the conversion, and the heat removed is fixed to the value that results in the selected outlet temperature. If the extent of reaction is restricted by the limiting reactant , the process indicates that the limiting conversion is reached by displaying the message "limiting reactant depleted". If the outlet temperature is below 0 °C or above 1,000 °C, the message "operating conditions unrealistic" appears.
Contributed by: Michael Wrobel and Rachael L. Baumann (November 2014)
Additional contributions by: Garret D. Nicodemus, John L. Falconer, and Nick Bongiardina
(University of Colorado Boulder, Department of Chemical and Biological Engineering)
Open content licensed under CC BY-NC-SA
The reaction takes place in a reactor with heat exchange. Reactants and and inert enter the reactor. The molar flow rates of each component exiting the reactor are calculated using the extent of reaction:
where and are the molar flow rates of component exiting and entering the reactor (mol/h), is the stoichiometric coefficient, and is the extent of reaction (mol/h).
The extent of reaction is:
where and are the enthalpies of the entering and exiting components (kJ/mol), is the heat of formation with a reference state at (kJ/mol), is heat capacity (kJ/[mol °C]), is temperature (°C), and is the heat removed (kJ/h).
The outlet temperature is:
This screencast video  show calculations for an energy balance on a reactor with heat transfer. This screencast  explores limiting reagents.
 Energy Balances with Unknown Outlet Conditions [Video]. (Dec 6, 2012) www.youtube.com/watch?v=FPDPxAp-Ms0.
 Limiting Reagent (Interactive) [Video]. (Nov 12, 2014) www.youtube.com/watch?v=7H2EnOzGxD0&feature=youtu.be&list=PLD4476BAFA5A65111.