Influence of impurities (nitrogen and methane) on the CO2 storage capacity as sediment-hosted gas hydrates – Application in the area of the Celtic Sea and the Bay of Biscay

Abstract

Deep saline aquifers are the most important potential storage reservoirs for CO 2 under supercritical conditions. Another option is the trapping of CO 2 in deep-sea sediments at low temperature, either in liquid state or as gas hydrates. The Negative Buoyancy Zone (NBZ) and the Gas Hydrate Stability Zone (GHSZ) are used to calculate the theoretical storage volume. It depends essentially on the geothermal gradient and on the quality of the injected CO 2. A sensitivity analysis shows that the storage volume in the Celtic Sea and the Bay of Biscay area is one order of magnitude lower if the injected fluid contains impurities like nitrogen or methane. Overall, the storage capacity in the French Exclusive Economic Zone (EEZ) exceeds 100 years of storage of the current French CO 2 emissions from large point sources. The conservative estimate of the EEZ storage capacity is found to be higher than in the deep saline aquifers of the Paris Basin. Moreover, the CO 2 storage capacity in this area is doubled when considering the zone beyond 200 miles from the shores. The implications of these results are potentially important for the long-term deployment strategy for CO 2 storage in France and in Western Europe.

Sulfur trioxide formation/emissions in coal‐fired air‐ and oxy‐fuel combustion processes: a review

“…The formation of H radicals is enhanced via reaction (22), and they then react with O 2 to form OH radicals according reaction (23). Moreover, FGR increases the level of impurities such as NO x , SO 2 and CO, which are believed to enhance SO 3 formation to some extent, as discussed below.…”

“…In addition, the nearly complete dehydration of the CO 2 stream is strongly desirable in order to inhibit corrosion, 20,21 and removal of various other impurities is necessary as they negatively affect all stages in the CCS chain. 22,23 Typical contents of impurities in CCS systems are shown in Table 2, specifically for three oxygen-purity scenarios for oxy-fuel technologies, resulting in 85.0%, 98.0 and 99.9% CO 2 in the flue gas stream, respectively. 24,25 It can be seen that SO 2 and SO 3 concentrations in the CO 2 streams are higher in oxy-fuel combustion than in the pre-combustion and post-combustion schemes.…”

“…Decomposition of HO 2 and OH release through reactions (22) and (23) shifts reaction (34) to the left and enhances SO 3 formation. In addition, the third-body efficiency of H 2 O is higher than that of CO 2 and N 2.…”

“…Sulfur dioxide in the CO 2 stream may also cause problems due to sulfation of calcium‐containing minerals and formation of sulfates that decrease the permeability and may affect the storage capacity of the reservoir. In addition, the nearly complete dehydration of the CO 2 stream is strongly desirable in order to inhibit corrosion, and removal of various other impurities is necessary as they negatively affect all stages in the CCS chain …”

Numerical investigation of the partitioning phenomenon of carbon dioxide and multiple impurities in deep saline aquifers

“…It should also be noted that most existing studies give priority to the investigations of the impact of one specific co-injected impurity, such as SO 2 , H 2 S, N 2 , O 2 or CH 4 , etc., while only a few experimental and numerical investigations have examined the effects of impurities in ternary mixtures, e.g. [15,[25][26][27]. Since practical CO 2 streams injected typically contain several kinds of non-CO 2 species, it is necessary to investigate the effects of multiple contaminants on the geological storage.…”