ChemSep Program

ChemSep is a suite of programs for performing multicomponent separation process calculations on PCs. It was created specifically for use by students in university courses on stagewise separation processes, but it is also used by professionals in industry. It includes ChemProp, a program that allows estimation of physical properties such as densities, viscosities, heat capacities and conductivities, and surface ten- 

The following feed, at 80°C and 1035 kPa, is to be fractionated at the rate of 1.0 kmol/s at the given pressure so that the vapor contains 98% of the propane, but only 1 % of the n-butane  

Component CH4 C2H6 C3Hg n-C4H10 n-C5H12 n-C6H14 

A number of simulations were carried out using the equilibrium model of ChemSep for different column configurations (number of equilibrium stages and feed stage location) and for differing operation specifications (reflux ratio and bottom product rate). Only the specifications and results of our final simulation are reported here. 

The problem specifications presented in Table 6.4 were entered via the ChemSep menu and the program was executed. A converged solution was achieved in five iterations on a PC running the Windows 2000 operating system. Initialization of all the variables was done by the program. The predicted separation is as follows  

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When you "Quit" the ChemSep program, you can run Word. Bitmap files can be imported into Word using the Insert/Picture command. The picture can be cropped (eliminate unwanted portions of the picture around edges) and resized using the Format/Picture command. You can also use the mouse to do this. 

The column has 30 sieve trays, with a total condenser and a partial reboiler. The solvent enters tray 5 and the feed enters tray 15, from the top. The pressure in the condenser is 1.1 atm the pressure at the top tray is 1.2 atm, and the pressure at the bottom is 1.4 atm. The reflux ratio is 5 and the bottoms rate is 960 kmol/h. Use the nonequilibrium model of the ChemSep program to estimate the separation achieved. Assume that the vapor and the liquid are both well mixed and that the trays operate at 75% of flooding. In addition, determine from the tray-by-tray results the average Murphree tray efficiency for each component. 

As a proof of the feasibility of such direct COSMO-RS process simulation, Taylor et al. [100] have linked the COSMOtherm program into their simulation program CHEMSEP [101] for distillation separation processes. For a number of typical separation problems they report very satisfying results, which are comparable with simulations based on empirical models. The simulation times were only a factor of 2 greater than those using empirical models. The quality of the simulations was considered as comparable to empirical models, although those were based on fitted experimental data. 

We will be using a computer program called ChemSep to simulate distillation. Today I d like to introduce this program. Compared with industrial software, it is user-friendly and written for student use. Below is the welcoming screen. 

The worked examples and simulation results in Chapter 14 were, for the most part, obtained with a simulation program known as ChemSep (Kooijman and Taylor, 1992). You will need to obtain this program (or something equivalent) in order to carry out the numerical exercises for this chapter. Contact R. Taylor for more information on the availability of ChemSep. 

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