To obtain pipeline grade methane, it is necessary to develop economical methods of separating methane from hydrogen and/or carbon monoxide mixtures. However, methane is usually produced along with hydrogen and/or carbon monoxide. We also need 6 Wilson parameters to determine a ternary mixtures properties.In coal gasification processes such as the flash hydropyrolysis or the Exxon catalytic process, methane is the major desired end product. We may similarly substitute for flash calculations.Д«oth the Wilson an NRTL equations are readily extended to manyu components.Д®xample: Find the dew point pressure and liquid phase mole fractions for a vapor mixture of acetone (1), methylacetate (2), and methanol (3) at 323K. Starting at, , we may determine the entire composition pressure diagram. Finally, for a binary mixture we must satisfy the criteria: This allows us to solve the fugacity forms of the EOS for and. We typically use mixture rules to get a m and b m for the EOS to find these roots. There will be 3 roots: liquid v, vapor v, and an 'unreal' middle root. To find the molar volumes: (using Redlich-Kuvorg)

YвЂ™s, VвЂ™s, P when we calculate a P xy diagram:

Instead we might directly use fugacity coefficients for both phases, and. We will also require CpвЂ™s DH vgsвЂ™s, (rigorously as f(T), but seldom all available.) Then we may solve the 4 equations iterativey until the proper roots are found.Д®xtrapolation of the activity coefficient approach to highter T & PвЂ™s may not be possible since: Also the modified RaoultвЂ™s Law requires an expression for P i Sat(T)and g i(T).

Since we do not know T, xвЂ™s, or V we must solve the equation A in conjunction with the previous flash criteria.ДЇor a binary system this gives us 4 equations and 4 unknowns. Here the energy balance must be used in conjunction with the mass balance and equilibrium criteria! (remember H vgs!) (A table may help)ДЄll of these methods become easy with root finding methods. Guess a value for V, solve for x 1 and x 2 from 1 & 2 : Determine if this satisfies 3. Here we must solve the following criteria: Find how much gas and liquid leave per mole of feed, and find the composition of both streams.Д¬hoose a basis of 1 mole feed/s. (Roots found are sensitive to initial guesses)ДЄ 40 mol% isobutane 160 mol%n n-pentane mixture flows into a flash chamber ad flashes at 49 В°Д¬ and 3.2 bar.

Estimate TDP and xвЂ™s for 0.36 mole fraction vapor ethanol (1) and hexane (2) at 1.013 bar.

Estimate T BP and yвЂ™s for acetone (1) вЂ“ water (2) mixture with x1=0.01, P = 1.013 bar.

Find the dew pressure and liquid composition in equilibrium with a 0.314 mole fraction nitromethane vapor, y 1) in carbon tetrachloride at 318K.

Pressure and vapor composition for a liquid mixture of ethanol (1) вЂ“ n hexane (2) at 331 K, X 1=0.412.

We must iteratively find the roots which satisfy all of the n + l equations. P i Sat and V i are known, but may require root finding program: For vapor composition:ДЄll Z i,P, and T are known find XвЂ™s, yвЂ™s, and V,L Find T bp and y i from P + X iвЂ™s: Use III to get T bp (unknown).Solve IV for X 1, and then V for P, since V i=f(x i) This may have to be done iteratively. To find the dew point pressure at a given T and Y: To find the bubble point pressure at a given,T, and composition, X, we know:.We may define the physical equilibrium constant, K i:ДЄt lower pressures (<10 bar) the fugarity coefficients in each phase are nearly equal:ДЄnd at these pressures the Poynting factor В»

Depriester chart with n propanol