Objective
In this article, we will explain how to model the Benfield Process in OLI’s flagship process simulator, Flowsheet: ESP.
Disclaimer: The user interface, calculations, and results displayed in this article are from OLI Flowsheet: ESP Version 12.0.0. Other software versions may appear different or present slightly distinct results due to continual developments to the software and thermodynamic databanks.
Purpose of the Benfield Process
The Benfield Process is used to remove acid gases (CO2 and H2S) from petroleum and industrial gases. The process involves two main steps:
Step 1. Gas Absorption
Potassium carbonate (K2CO3) is used as the alkali in the absorption solvent, enabling the solvent to dissolve and capture significantly more CO2 and H2S than would be possible with water alone.
Step 2. Potassium Carbonate Solvent Regeneration
The spent solvent is steam-stripped in the Regenerator tower to remove the absorbed CO2 and H2S, regenerating the solvent for reuse in the Absorber after energy recovery through heat exchangers.
Chemical Mechanisms
Absorber: Carbon Capture Reaction:
Absorber: Hydrogen Sulfide Capture Reaction:
In the Regenerator, these reactions proceed from right to left to release CO2 and H2S.
Using the Benfield Process Case File in OLI Flowsheet: ESP
In the following video, we review a Benfield Process example in OLI Flowsheet: ESP. The case file can be accessed in the software by navigating to:
File > Examples > Benfield Sensitivity Analysis.esp
Users can further customize this case file to match their specific process parameters.
Conclusion
With OLI Flowsheet: ESP, users can confidently model the complex chemistry and process-specific parameters of the Benfield Process. The software’s sensitivity analysis feature allows for investigation and optimization of acid gas capture efficiency.