Carbon dioxide (CO2) capture from a slipstream
of steam
reformer flue gas (18–20 vol %wet CO2) using 30 wt % aqueous monoethanolamine was performed for ∼500
h in a mobile test unit (∼120 kg CO2/h). Specific
reboiler duties (SRDs) of 3.6–3.8 MJ/kg CO2 were
achieved at 90% capture. The pilot data validate the modeling of off-design
partial capture, that is, operation at lower CO2 capture
rates (at constant gas flow) than the absorption column was designed
to achieve. This paper demonstrates that off-design partial capture
enables significant energy savings (SRD, cooling) relative to on-design
capture. The accrued savings depend on the column design (packing
height, flooding approach) and the feed CO2 concentration.
Finally, a concept for stepwise deployment of carbon capture and storage
in industries with high-CO2 concentration sources (e.g.,
steel and cement manufacturing and refining) is introduced. Thanks
to its inherent full-capture-ready design, the initial energy-efficient,
off-design partial capture operation can be extended to full capture
over time.