Supercritical designing

Fig. 5. Martin Lake unit of Texas Utilities Services, Inc., 750 MW a representative of modem supercritical design.

The Super LWRs can utilize the existing mature technology of the supercritical turbine from supercritical water cooled FPPs, so significant research in this area is not needed. Table 3.2 summarizes the worldwide distribution of fossil-fired supercritical plants. Most new coal-fired power plants are supercritical. Design and developments of supercritical FPPs are introduced in Appendix A of this book. 

Solute/Solvent Systems The gamma/phi approach to X T.E calculations presumes knowledge of the vapor pressure of each species at the temperature of interest. For certain binary systems species I, designated the solute, is either unstable at the system temperature or is supercritical (T > L). Its vapor pressure cannot be measured, and its fugacity as a pure liquid at the system temperature/i cannot be calculated by Eq. (4-281). 

Ionic liquids have been described as designer solvents [11]. Properties such as solubility, density, refractive index, and viscosity can be adjusted to suit requirements simply by making changes to the structure of either the anion, or the cation, or both [12, 13]. This degree of control can be of substantial benefit when carrying out solvent extractions or product separations, as the relative solubilities of the ionic and extraction phases can be adjusted to assist with the separation [14]. Also, separation of the products can be achieved by other means such as, distillation (usually under vacuum), steam distillation, and supercritical fluid extraction (CO2). 

Boilers can operate at subcritical, critical, or supercritical pressures, either in once-through or recirculating designs. 

Designs include the once-through boiler, which can operate at sub-critical, critical, or supercritical pressures and at all commercial temperatures, and the radiant boiler, where heat absorption is largely by radiant energy transfer. 

An interesting recent example of successful application of the SSG process combined with ensuing supercritical drying is the design of titania-silica mixed oxides for the epoxidation of bulky olefins [16-18]. This example will be used to illustrate the opportunities the combined use of SSG and SCD provide for tailoring the chemical and structural properties of mixed oxides. 

Gasafi, E., Meyer, L., Schebek, L. (2004) Using Life-Cycle Assessment in Process Design Supercritical Water Gasification of Organic Feedstocks. Journal of Industrial Ecology, 7(3M), 75-91. 

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