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# Co2 Absorption Column - Mechanical Design

co2 absorption amdea

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### #1 AyrtonB

AyrtonB

Junior Member

• Members
• 10 posts

Posted 18 February 2018 - 10:34 AM

Hello everyone,

I'd be grateful for any advice on the design of my CO2 absorption unit within an Ammonia plant, thank you in advance for all replies.

Question

I'm looking for any recommended textbooks for the mechanical design of my column as well as any BSs or ISOs I should be aware of. At a minimum I would like to calculate values such as the active area of my trays, downcomer size, thickness of walls,flange size, type of plates etc.

Additionally, any anecdotal information or heuristics regarding mechanical design would be very handy too.

Context:

I am using activated MDEA (aMDEA) at a concentration of 30 wt% MDEA, 3 wt% Piperazine (PZ) with the remaining solution being water, it enters the column at 32 degC. The gas stream from which CO2 is being removed enters at 35 degC and contains:

H2O = Neglibile

CH4 = 0.69%

CO = 0.2%

CO2 = 17.87%

H2 = 61.42%

N2 = 19.5%

Ar = 0.23%

Total Flowrate = 224,910 kg/hr

Much of the literature I have read suggest that both Aspen Plus and HYSYS model the reactions between CO2, MDEA and PZ poorly, as I don't have access to software such as ProMax or ProTreat I have opted to base my design off of experimental data. Using a paper which gave partial pressures and CO2 loading across a range of temperatures I have formed a model in Matlab which accounts for the high heat of reaction.

For a removal of 99% at a column pressure of 25.7 bar my model had a result of 18 trays required and the gas stream leaves at 60 degC.. The CO2 loading is at 0.5 (mol CO2/mol amine) and the lean solvent enters at 508 L/s. Further calculations gave the column diameter to be 3.7m with a height of 12.4m.

Edited by AyrtonB, 18 February 2018 - 12:22 PM.