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Techno-economic Evaluation of CO2 Capture from Flue Gases Using Encapsulated Solvent
journal contribution
posted on 2017-01-19, 00:00 authored by Anggit Raksajati, Minh T. Ho, Dianne E. WileyEncapsulated solvents are a solvent
system for CO2 capture,
where the operating solvent fluid is enclosed in a thin membrane capsule
with a diameter of 100–600 μm. The encapsulation provides
a significantly higher surface area compared to conventional packings,
which potentially reduces the absorber dimensions. In this paper,
a high-level assessment of costs for postcombustion CO2 capture using encapsulated solvent systems is carried out to identify
key areas for future development. Two process configurations for an
encapsulated solvent system are assessed. In the first process configuration,
multiple fixed-bed columns are used as the absorber and regenerator.
In the second process configuration, a circulating fluidized-bed absorber
and a bubbling fluidized-bed regenerator are used. For each system,
possible cost reductions through improvements in the capsule properties
are investigated. Key design and operational challenges for these
systems are also evaluated. The capture costs for using an encapsulated
MEA 30% wt. solvent system are found to be 60% to 2 times higher than
a conventional MEA solvent system. Higher capture cost is due to the
extra membrane resistance in the encapsulated system which increases
the regeneration energy required, coupled with higher equipment and
capital cost. To reduce cost, future developments for an encapsulated
solvent system should consider implementing a suitable heat recovery
scheme within the process, using novel absorber and/or regenerator
column designs and using solvents encased in very thin capsules. The
performance of the encapsulated system could also be improved by using
solvents other than MEA with more favorable properties.