CO(2) Capture and Storage (CCS) is a good strategy to mitigate levels of atmospheric greenhouse gases. The type and quantity of impurities influence the properties and behavior of the anthropogenic CO(2), and so must be considered in the design and operation of CCS technology facilities. Their study is necessary for CO(2) transport and storage, and to develop theoretical models for specific engineering applications to CCS technology. In this work we determined the influence of CH(4), an important impurity of anthropogenic CO(2), within different steps of CCS technology: transport, injection, and geological storage. For this, we obtained new pressure-density-temperature (PρT) and vapor-liquid equilibrium (VLE) experimental data for six CO(2) + CH(4) mixtures at compositions which represent emissions from the main sources in the European Union and United States. The P and T ranges studied are within those estimated for CO(2) pipelines and geological storage sites. From these data we evaluated the minimal pressures for transport, regarding the density and pipeline's capacity requirements, and values for the solubility parameter of the mixtures, a factor which governs the solubility of substances present in the reservoir before injection. We concluded that the presence of CH(4) reduces the storage capacity and increases the buoyancy of the CO(2) plume, which diminishes the efficiency of solubility and residual trapping of CO(2), and reduces the injectivity into geological formations.

Dew points for two synthetic natural gas (SNG) mixtures between 1.2 × 10 5 and 81.8 × 10 5 Pa in the temperature range from 213.6 to 261.4 K, four SNG + water mixtures between 1.1 × 10 5 and 41.0 × 10 5 Pa and temperatures from 244.7 to 288.1 K, and four SNG + water + methanol mixtures between 1.1 × 10 5 and 20.7 × 10 5 Pa and temperatures from 247.6 to 288.6 K were experimentally determined. The experimental results obtained on the multicomponent systems were analyzed in terms of a predictive excess function-equation of state (EF-EOS) method, which reproduced experimental dew point temperature data with absolute average deviation (AAD) between 0.9 and 3.1 K for the dry systems, from 0.0 to 1.6 K for the systems with water, and from 0.0 to 3.0 K for the systems with water and methanol. The experimental results obtained for synthetic natural gas (SNG) + water mixtures at pressure values higher than 5 × 10 5 Pa were also compared to a predictive equation of state (EOS) model. It reproduced experimental dew point temperature data within AAD between 1.8 and 5.3 K.

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Reliable speed of sound, c, values in CO 2 -rich mixtures and pure CO 2 are required for carbon capture and storage (CCS) technology but are difficult to determine, particularly at relatively high frequencies. We tested the suitability of methanol as doping agent to obtain accurate c values in CCS systems at 5 MHz. We measured c in seven CO 2 -rich, CO 2 +methanol mixtures between 263.15 and 323.15 K and up to 196.30 MPa, and we extrapolated the values to obtain c in pure CO 2 .Additionally, we measured c from 263.15 to 373.19 K and up to 190.10 MPa in two CO 2 -rich, CO 2 +SO 2 mixtures with the same SO 2 composition, which is of interest for CCS, with one mixture doped with methanol. We compared our results for pure CO 2 with the literature and the Span and Wagner equation of state (EoS). We validated the PC-SAFT EoS and the modeling with the REFPROP 9 software for the mixtures by comparing the predicted values with our experimental data under the studied conditions. We conclude that methanol is a suitable doping agent to measure c in pure CO 2 and CO 2 -rich mixtures. For the CO 2 +SO 2 mixtures, the effect of methanol on the experimental values is small and negligible for modeling. *Manuscript Click here to download Manuscript: Revised Manuscript.docx Click here to view linked References