Ratio control: Ammonia synthesis reactor

Lecture notes for Advanced modeling and Control

Author

Ranjeet Utikar

Published

July 26, 2023

Example 15.1 from (Seborg et al. 2016)

A ratio control scheme is to be used to maintain a stoichiometric ratio of H2 and N2 as the feed to an ammonia synthesis reactor Figure 1. Individual flow controllers will be used for both the H2 and N2 streams. Using the information given below,

  1. Draw a schematic diagram for the ratio control scheme.
  2. Specify the appropriate gain for the ratio station, \(K_R\).

Available information:

  1. The electronic flow transmitters have built-in square root extractors. The spans of the flow transmitters are 30 L/min for H2 and 15 L/min for N2.

  2. The control valves have pneumatic actuators.

  3. Each required current-to-pressure (I/P) transducer has a gain of 0.75 psi/mA.

  4. The ratio station is an electronic instrument with 4–20 mA input and output signals.

Figure 1: Ammonia synthesis reactor

References

Seborg, Dale E., Thomas F. Edgar, Duncan A. Mellichamp, and Francis J. Doyle III. 2016. Process Dynamics and Control. John Wiley & Sons. https://books.google.com?id=ZZVFEAAAQBAJ.

Citation

BibTeX citation:
@online{utikar2023,
  author = {Utikar, Ranjeet},
  title = {Ratio Control: {Ammonia} Synthesis Reactor},
  date = {2023-07-26},
  url = {https://amc.smilelab.dev//content/notes/02-ratio_and_feedforward_control/ammonia_synthesis_reactor.html},
  langid = {en}
}
For attribution, please cite this work as:
Utikar, Ranjeet. 2023. “Ratio Control: Ammonia Synthesis Reactor.” July 26, 2023. https://amc.smilelab.dev//content/notes/02-ratio_and_feedforward_control/ammonia_synthesis_reactor.html.