Category: Multiphase Equilibrium

So-called white oil is pressurized and cooled gas well vapors. In Texas awhile back, independent producers operated refrigeration units (to as low as −20°F) at their wells, exploiting a 1977 letter from the legal counsel of the Texas Railroad Commission (the agency that governed oil and gas production) that said “white oil” could be deemed…

In Section 7.3, we discussed vapor-liquid equilibria of a pure component. In Section 7.4, we covered equilibria of a pure component in the presence of a noncondensable gas. In this section, we consider certain aspects of a more general set of circumstances, namely, cases in which both the liquid and vapor have two components; that is, the…

From a single-component two-phase system, let’s extend the discussion to a more complicated system, namely, a system with two components in the gas phase together with a single-component liquid system. An example of such a system is water and a noncondensable gas, such as air. The equilibrium relationships for the water and air help explain…

You can see from Figure 7.2 (line AB) that the function of p* versus T is not a linear function (except as an approximation over a very small temperature range). Many functional forms have been proposed to predict p* from T, but we use the Antoine equation in this text because it has sufficient accuracy for our needs, and coefficients for the equation exist in…

You can understand the behavior of single-component two-phase systems by examining the phase diagram of the component of interest. For example, consider the p*-versus-T diagram (at constant V^) for water shown in Figure 7.3. The relationship between temperature and pressure for steam and liquid water phases in equilibrium is represented by the line from the triple point up to…

You can conveniently display the properties of compounds via phase diagrams. A pure substance can exist in many phases simultaneously of which, as you know, solid, liquid, and gas are the most common. Phase diagrams enable you to view the properties of two or more phases as functions of temperature, pressure, specific volume, concentration, and…

The most common pieces of equipment in the process industries are separation devices, which remove one or more components from a stream and concentrate them in another stream. Mixing of components occurs regularly in nature (e.g., minerals dissolve in rainwater as the water flows down a creek bed), but to separate components requires separation equipment…