Department of Geotechnology, Delft University of Technology, Delft 2628CN, The Netherlands.
J Colloid Interface Sci. 2011 Dec 1;364(1):237-47. doi: 10.1016/j.jcis.2011.07.091. Epub 2011 Aug 12.
Geological sequestration of pure carbon dioxide (CO(2)) in coal is one of the methods to sequester CO(2). In addition, injection of CO(2) or flue gas into coal enhances coal bed methane production (ECBM). The success of this combined process depends strongly on the wetting behavior of the coal, which is function of coal rank, ash content, heterogeneity of the coal surface, pressure, temperature and composition of the gas. The wetting behavior can be evaluated from the contact angle of a gas bubble, CO(2) or flue gas, on a coal surface. In this study, contact angles of a synthetic flue gas, i.e. a 80/20 (mol%) N(2)/CO(2) mixture, and pure CO(2) on a Warndt Luisenthal (WL) coal have been determined using a modified pendant drop cell in a pressure range from atmospheric to 16 MPa and a constant temperature of 318 K. It was found that the contact angles of flue gas on WL coal were generally smaller than those of CO(2). The contact angle of CO(2) changes from water-wet to gas-wet by increasing pressure above 8.5 MPa while the one for the flue gas changes from water-wet to intermediate-wet by increasing pressure above 10 MPa.
将纯二氧化碳（CO2）地质封存于煤中是封存 CO2 的方法之一。此外，将 CO2 或烟道气注入煤中可以提高煤层甲烷的产量（ECBM）。该联合工艺的成功与否强烈取决于煤的润湿性，这取决于煤阶、灰分、煤表面的非均质性、压力、温度和气体组成。润湿性可以通过气泡（CO2 或烟道气）在煤表面的接触角来评估。在这项研究中，使用改进的悬滴室在大气至 16 MPa 的压力范围内和 318 K 的恒定温度下测定了合成烟道气（即 80/20（mol%）N2/CO2 混合物）和纯 CO2 在 Warndt Luisenthal（WL）煤上的接触角。结果发现，烟道气在 WL 煤上的接触角通常小于 CO2。当压力高于 8.5 MPa 时，CO2 的接触角从水湿变为气湿，而烟道气的接触角从水湿变为中间湿。
