Minimal feed gas temperature for amine unit.

[Microcog]

80F is classical limitation, but I've seen 2 O&GJ articles described real opreating plants with 40-65 F; some examples in Kohl&Nielsen are 48-65F; Amine Experts mentioned cold feed gas cases...

Any ideas where this limitation come from?

 

[georgeverghese]

The min feed gas temp is limited to
(a) a min of at least say 5degC margin to the hydrocarbon dewpoint of the exit gas from the contactor at a composition which represents the min possible CO2 and/or H2S content of this exit stream when at max normal contactor pressure
(b) a min of at least say 5degC margin to the hydrate temp of the feedgas at max operating pressure

There would be some minimal effect on mass transfer eff at lower temp given the slightly higher viscosity of the lean amine solution

 

[pierreick]

Hi,
Take a look at this resource.
Pierre

 

[georgeverghese]

Criteria posted earlier is relevant to alkanolamine solvents. There are other non alkanolamine solvents that can operate with much lower feedgas temp ( ranging down to -100degF for methanol based Rectisol process), and these processes serve the secondary intent to extract heavy hydrocarbons out of the feedgas also. See literature on applications specific to each solvent for feedgas temp lower limit. The criterion I posted assumes no intent to co adsorb heavy hydrocarbons out of the feedgas.

What is the license process and solvent here ? Do you need to extract some heavy hydrocarbons out of the feedstream here ?