This screencast demonstrates the use of reactor models RStoic, RGibbs, RPlug, and RCSTR through
an example problem on the production of ethyl acetate. Open your Aspen simulation and begin
a new flow sheet using metric units. To start, enter your process components, ethanol, acetic
acid, ethyl acetate, and water. Choose NRTL HOC as your method. Watch the related method
video to learn more about choosing a property method. When all information is entered, run
the property analysis and then go to the simulation environment. To run all four reactors in one
simulation, create a duplicator block, which duplicates an inlet stream and can send it
to multiple locations. Create a RStoic, RGibbs, RPlug, and RCSTR reactor, renaming each as
such. Add a feed stream into your duplicator, and connect the duplicator outlets to each
reactor, naming the streams F-Reactor Type. Create product streams from each reactor,
naming them P-Reactor Type. When you're done, your flow sheet should look like this. Click
the green next arrow to specify the feed conditions. The stream enters at 70 degrees Celsius and
1 atmosphere. Input the following parameters in kilomoles per hour. 8.892 water, 186.59
ethanol, and 192.6 acetic acid. Click the green next arrow to go to the duplicator block.
There is no information to enter here, so click the green arrow again. For the sake
of comparison, all reactors will be specified at 1 atmosphere and 70 degrees Celsius. Make
sure all reactors have vapor-liquid selected as the valid phases. For the CSTR, specify
a volume of 0.14 cubic meters. You can see that the RCSTR model requires a reaction to
be entered before you can proceed in the simulation. At this point, scroll down on the menu tree
and click on the reactions folder. Click new, leave the label as R1, and select a POWERLAW
reaction type. Click new again, and enter the forward reaction: ethanol and acetic acid
goes to ethyl acetate and water. Assume the reaction is first order with respect to each
of the reactants, and zeroth order with respect to each of the products. Enter -1 and 1 for
the coefficients, and 1 and 0 for the exponents of your reactants and products, respectively.
Now we'll enter the reverse reaction: ethyl acetate plus water goes to ethanol and acetic
acid. Enter -1 and 1 for the coefficients, and 1 and 0 for the exponents of your reactants
and products, respectively. Press the green arrow to input the reaction's kinetic information.
For both reactions, the reacting phase will be liquid, and the concentration basis will
be molarity. For the forward reaction, specify a k value as 1.9 * 10^8, and an E value as
5.95*10^7 J/kmol. Make sure the units are correct before proceeding. Repeat the procedure
for the reverse reaction by selecting it from the dropdown menu. The k value for the reverse
reaction is 5.0*10^7, and the E value is 5.95*10^7 J/kmol. Press the green arrow to go back to
the CSTR reaction tab. You can now move the R1 reaction to your selected reaction set.
Pressing the green arrow brings you to RGibbs. Remember the reactor is operating at 1 atmosphere
and 70 degrees Celsius. Press the green next arrow to move on to RPlug. Choose reactor
with specified temperature as the operating type, and choose the operating condition "Constant
at specified reactor temperature." Enter 70 degrees Celsius. Pressing the green arrow
brings you to the configuration tab. Input a length of 2 meters and a diameter of 0.3
meters. Insure the process stream valid phases are vapor-liquid. Go the reactions tab and
select R1 and your reaction set. Pressing the green arrow again brings you to RStoic.
Input your reactor temperature and pressure. On the reactions tab, click new and input
the forward reaction with the appropriate coefficients. Enter 0.7 as the fractional
conversion of ethanol. Press the green arrow and run the simulation. Open the stream summary
to view the results. You can compare the production rate of ethyl acetate of the four reactors.
You can see that RGibbs actually produces the most ethyl acetate, while RCSTR produces
the least. Additionally, if you click on the CSTR Results block on the menu tree, you can
see the heat duty required for this equipment. Watch the following video in the YouTube playlist
to see an application of the reactors chapter on a chlorobenzene production plant.