The Hydrogenation Process

Hydrogenation is the chemical addition of hydrogen to a hydrocarbon in the presence of a catalyst, a severe form of hydrogen treating.

Hydrogenation may be either destructive or non-destructive. In the former case, hydrocarbon chains are ruptured (cracked) and hydrogen is added where the breaks have occurred. In the latter, hydrogen is added to a molecule that is unsaturated with respect to hydrogen. In either case, the resulting molecules are highly stable.

Hydrogenator Design and Control

The use of hydrogen requires precautions against creating an explosive mix of hydrogen and air. Typically, a hydrogenation vessel undergoes a pressure test followed by several nitrogen purges before hydrogen is introduced. Similarly, at the end of the reaction process, the vessel is purged with nitrogen in order to leave it in a safe condition. Normally, a hardwired safety system confirms the pressure test and nitrogen purge phases before allowing the hydrogen line to be opened.

Hydrogenation requires high pressures to be maintained in the reaction vessel – giving problems over maintaining seals around agitators which in some cases require additional seal integrity checks or upgrades to incorporate magnetic coupling systems.

Hydrogenation also tends to be a highly exothermic reaction, resulting in demanding temperature control requirements.

The R&D and Clinical Trials environments in which many small scale hydrogenation vessels operate are such that facilities must cater for a variety of products each having precisely defined requirements both for the hydrogen addition itself and for the associated temperature profile.

A control system must therefore provide flexibility in the way in which accurate and repeatable control of the hydrogenation environment is achieved and will include the following features:

Sequential control for vessel pressure testing, purging and hydrogen addition.
Precise loop control for temperature and pressure (temperature setpoint profile programming is also available on the T800 if required).
Secure collection of on-line data from the hydrogenation process for analysis and evidence.
Local operator display with clear graphics and controlled access to parameters

The EyconTM Visual Supervisor is an ideal solution for this application.