The range and level of impurities in CO2 streams from different carbon capture sources

Abstract

For CO 2 capture and storage deployment, the impact of impurities in the gas or dense phase CO 2 stream arising from fossil fuel power plants, or large scale industrial emitters, is of fundamental importance to the safe and economic transportation and storage of the captured CO 2 . This paper reviews the range and level of impurities expected from the main capture technologies used with fossil-fuelled power plants in addition to other CO 2 emission-intensive industries. Analysis is presented with respect to the range of impurities present in CO 2 streams captured using pre-combustion, post-combustion and oxy-fuel technologies, in addition to an assessment of the different parameters affecting the CO 2 mixture composition. This includes modes of operation of the power plant, and different technologies for the reduction and removal of problematic components such as water and acid gases (SO x / NO x ). A literature review of data demonstrates that the purity of CO 2 product gases from carbon capture sources is highly dependent upon the type of technology used. This paper also addresses the CO 2 purification technologies available for the removal of CO 2 impurities from raw oxy-fuel flue gas, such as Hg and noncondensable compounds. CO 2 purities of over 99 % are achievable using post-combustion capture technologies with low levels of the main impurities of N 2 , Ar and O 2 . However, CO 2 capture from oxy-fuel combustion and integrated gasification combined cycle power plants will need to take into consideration the removal of non-condensables, acid gas species, and other contaminants. The actual level of CO 2 purity required will be dictated by a combination of transport and storage requirements, and process economics.

High pressure CO 2 CCS pipelines: Comparing dispersion models with multiple experimental datasets

“…The fourth set of inlet conditions are matched to QUEST T12 concerning a release of pure CO 2 in the CO2QUEST project. The fifth set of inlet conditions idealise the fourth set of conditions for a mixture of 96% CO 2 and 4% N 2 , typical of impurity levels expected in pipeline transport of CO 2 from power generation (Cooper and Barnett, 2014;Porter et al, 2015). Specifically, they achieve the same mass-flow rate and hence are directly comparable to the fourth set of inlet conditions and also the impure CO 2 tests from CO2QUEST.…”

Molecular simulation of the thermophysical properties and phase behaviour of impure CO2 relevant to CCS

“…The upper transport temperature will be set by the compressor discharge temperature and the temperature limits of the pipeline and the lower temperature will correspond to the winter ground temperature of the surrounding soil 3 . Expected impurity levels are about 4%, with N 2 , O 2 , Ar and H 2 being key impurities 1,2,4,5 . This range of pressure, temperature and impurity level define pipeline operating conditions and provide a target window for CCS-oriented modelling.…”

Cost and performance of some carbon capture technology options for producing different quality CO 2 product streams

“…However, the compression and dehydration only case has the lowest capital cost expressed in €/kW-net due to its lower CO2 capture energy penalty. As one might expect, the cost of electricity increases with increasing CO2 purity, due largely to the increasing energy penalty for CO2 purification (Kather and Kownatzki, 2011;Pipitione and Bolland, 2009;Porter et al, 2015) …”

“…monoethanolamine (MEA) and Selexol TM ) used for capture (Porter et al, 2015). CO2 impurities are known to have a number of mainly detrimental impacts on the downstream transport and storage CCS chain elements.…”