Wettability determination by contact angle measurements: HvbB coal-water system with injection of synthetic flue gas and CO 2

Department of Geotechnology, Delft University of Technology, Delft 2628CN, The Netherlands.
Journal of Colloid and Interface Science (Impact Factor: 3.37). 08/2011; 364(1):237-47. DOI: 10.1016/j.jcis.2011.07.091
Source: PubMed

ABSTRACT 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.

Download full-text


Available from: Narjes Shojai Kaveh, Mar 24, 2015
39 Reads
  • Source
    • "Under similar conditions, γ for CO 2 /water and CO 2 /brine show similar evolution with respect to temperature and temperature (Chun and Wilkinson, 1995; Chalbaud et al., 2010). It decreases with pressure at constant temperature and this is more significant at lower pressure near the critical region (Shojai Kaveh et al., 2011; Nielsen et al., 2012) especially at low temperature (Chalbaud et al., 2010). At higher pressure, plateau is reached at the value of γ for the system that slightly increases with salt concentration at constant temperature (Chalbaud et al., 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this review, various aspects of geological carbon sequestration are discussed in relation to the principles of two-phase flow in porous media. Literature reports on geological sequestration of CO2 show that the aquifer storage capacity, sealing integrity of the caprock, and the in situ processes, for example, the displacement of brine by supercritical CO2 (scCO2), convection–diffusion–dissolution processes involving scCO2 and brine, geochemical reactions, and mineral precipitation depend on the fluid–fluid–rock characteristics as well as the prevailing subsurface conditions. Considering the complexity of the interrelationships among various processes, experimental investigations and network of mathematical functions are required for the ideal choice of geological site with predictable fluid–fluid–rock behaviors that enhance effective monitoring. From a thorough appraisal of the existing publications, recommendations are made for improvement in the existing simulators to fully couple the entire processes involved in the sequestration operations and in situ mechanisms which include injection rate and pressure, brine displacement, simultaneous flow of free and buoyant phases of CO2, various trapping mechanisms, convection–diffusion–dissolution processes, scCO2–brine–rock reactions, precipitation of the rock minerals, and the consequences on the hydraulic and hydrogeological properties in the course of time as well as the quantity of injected CO2. Suggestion is made for the inclusion of leakage parameters on site-specific basis to quantify the risks posed by the prevailing fluid–fluid–rock characteristics as well as their immediate and future tendencies. Calls are also made for thorough investigations of factors that cause nonuniqueness of the two-phase flow behavior with suggestions for the use of appropriate experimental techniques. The review comprehensively synthesizes the available knowledge in the geological carbon sequestration in a logical sequence.
    Critical Reviews in Environmental Science and Technology 03/2015; 45:1105–1147. DOI:10.1080/10643389.2014.924184 · 3.47 Impact Factor
  • Source
    • "A large value of P a means that the surface is rough and a small P a factor indicates a smooth surface (i.e., the P a value of a glass surface is about 0.1 ␮m). A more detailed description on determination of P a value is given by Shojai Kaveh et al. (2011) "
    [Show abstract] [Hide abstract]
    ABSTRACT: The injection of carbon dioxide (CO2) or flue gas into coal layers enhances the coal bed methane production (ECBM) and offers an option for CO2-storage. The success of this process depends on different factors, among them wetting behavior of the coal plays an important role, which is a function of pressure, temperature, coal rank and composition of the gas.The wettability behavior of wet coal samples (semi-anthracite), with respect to injection of synthetic flue gas and pure CO2, was investigated in a modified pendant drop cell at a constant temperature of 318 K and pressures varying between 0.2 and 16 MPa. For the semi-anthracite Selar Cornish sample, the wettability alteration from intermediate-wet to gas-wet with CO2 injection was observed at pressures above 5.7 MPa. Experimental results with synthetic flue gas revealed that the wettability of Selar Cornish coal is intermediate-wet at all pressures and the contact angle only slightly increases with increasing pressure.Comparison between high rank (semi-anthracite) and medium (high volatile bituminous (hvBb)) coals confirms that hydrophobicity increases with the coal rank for samples with a similar bulk mineral content. The results of the contact angle experiments are input parameters for field scale reservoir modeling.
    International Journal of Greenhouse Gas Control 11/2012; 11:S91–S101. DOI:10.1016/j.ijggc.2012.09.009 · 3.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To quantify and rank gas wettability of coal as a key parameter affecting the extent of CO2 sequestration in coal and CH4 recovery from coal, we developed a contact angle measuring system based on a captive gas bubble technique. We used this system to study the gas wetting properties of an Australian coal from the Sydney Basin. Gas bubbles were generated and captivated beneath a coal sample within a distilled water-filled (pH 5.7) pressurised cell. Because of the use of distilled water, and the continuous dissolution and shrinkage of the gas bubble in water during measurement, the contact angles measured correspond to a ‘transient receding’ contact angle. To take into account the mixed-gas nature (CO2, CH4, and to a lesser extent N2) of coal seam gas in the basin, we evaluated the relative wettability of coal by CH4, CO2 and N2 gases in the presence of water. Measurements were taken at various pressures of up to 15 MPa for CH4 and N2, and up to 6 MPa for CO2 at a constant temperature of 22°C. Overall, our results show that CO2 wets coal more extensively than CH4, which in turn wets coal slightly more than N2. Moreover, the contact angle reduces as the pressure increases, and becomes < 90° at various pressures depending on the gas type. In other words, all three gases wet coal better than water under sufficiently high pressure.
    Geofluids 03/2014; 14. DOI:10.1111/gfl.12078 · 2.05 Impact Factor
Show more