Mole fraction conversion

Figure 3.31 Effects of alternating change of the ethylene mole fraction. Conversion (left) and selectivity (right) as a function of cycle time [102. ...

N/No oi w /100 and mole fraction conversion nearly equals the weight fraction conversion.]... 

Put in lines 85 to 134 from PR3LV, but skip 101,102, and 103 since the weight-to-mole fraction conversions are handled inside of SLCHEMPOT. 

Sometimes it helps to assume a value to work with, especially with intensive properties such as concentrations. We will encounter problems of this type later, for example in molality to mole fraction conversions (Section 6.4). 

The special case involving the removal of a low (2—3 mol %) mole fraction impurity at high (>99 mol%) recovery is called purification separation. Purification separation typically results in one product of very high purity. It may or may not be desirable to recover the impurity in the other product. The separation methods appHcable to purification separation include equiUbrium adsorption, molecular sieve adsorption, chemical absorption, and catalytic conversion. Physical absorption is not included in this Hst as this method typically caimot achieve extremely high purities. Table 8 presents a Hst of the gas—vapor separation methods with their corresponding characteristic properties. The considerations for gas—vapor methods are as follows (26—44). 

At atmospheric pressure, the conversion to trichlorosilane is limited to about 16%. The conversion of SiCl to HSiCl was found to be at equiUbrium. If contact time was greater than 45 s and the mole ratio of hydrogen to siUcon tetrachloride 1 1, then at 14 kPa (2 psi) and 550°C, the HSiCl mole fraction reached 0.7 but substantial formation of H2SiCl2 occurred (62). Enhancements in yield have been reported through preactivating the siUcon mass by removal of oxides (73) and the rapid thermal quench of the effluent gas stream (74). The reduction of siUcon tetrachloride in a plasma has also been reported (75). 

The conversion is simplest when and Ke a are defined in terms of mole-fraction driving force ... 

The production of copper from sulphide minerals is accomplished with a preliminary partial roast of die sulphides before reaction widr air in the liquid state, known as mattes, to form copper metal (conversion). The principal sources of copper are minerals such as chalcopyrite, CuFeSa and bornite CuaFeSa, and hence the conversion process must accomplish the preferential oxidation of non, in the form of FeO, before the copper metal appears. As mentioned before, tire FeO-SiOa liquid system is practically Raoultian, and so it is relatively easy to calculate the amount of iron oxidation which can be canned out to form this liquid slag as a function of the FeO/SiOa ratio before copper oxidation occurs. The liquid slag has a maximum mole fraction of FeO at the matte blowing temperatures of about 0.3, at solid silica saturation. 

First it is important to study how the gradual conversion of soda will influence the rate of reaction. Initially, keep all other conditions constant that can influence the rate oxygen and water concentration, and the mole fraction of TCE in the reactor. This last is the same as the TCE in the discharge flow from the reactor. 

This case includes most liquid reactions and also those gas reactions that operate at both constant temperature and pressure with no change in the number of moles during reaction. The relationship between concentration C and fractional conversion is as follows ... 

Since the volume depends on conversion or time in a constant pressure batch reactor, consider the mole balance in relation to the fractional conversion X. From the stoichiometry. 

From Equation 5-8, the amount reacted in terms of the fractional conversion and the initial moles is... 

Molarity (M) A concentration unit defined to be the number of moles of solute per liter of solution, 95q, 259 concentration unit conversion, 261-262 potassium chromate, 263 Mole A collection of6.0122 X 1023 items. The mass in grams of one mole of a substance is numerically equal to its formula mass, 55. See also Amount Mole fraction (X) A concentration unit defined as the number of moles of a component divided by the total number of moles, 116-117,261 Mole-gram conversions, 55-56,68-68q... 

If mi, m2 are the total moles of residual monomers 1 and 2 respectively, and M° is the total mols of monomers charged initially, then the fractional conversion C at any time during the polymerization is given by. 

We have information about molarity (mol/L) and density (g/mL) and are asked to find molality (mol/kg) and mole fraction (mol/mol). A good way to approach conversions from molarity to another measure is to choose a convenient volume for the solution, determine its mass and the mass of solute, and find the mass of water by difference. Then convert mass of water to kilograms and to moles to complete the calculations. 

Thus, for an almost empty surface, the rate assumes its maximum ivith equal amounts of reactants, at the limit of zero conversion. Again, we need to assess the validity of the approximations under the conditions employed. Nevertheless, the above procedure for determining the reaction rate as a function of mole fraction can be quite useful in the exploration of reaction mechanisms. 

Figure 8.10. Methanol synthesis rate over a Cu(lOO) single crystal in the zero conversion limit as a function of the H2 mole fraction. The full line corresponds to the kinetic model in Eqs. (23-35) with reaction (33),...

The composition of the increment of polymer formed at a monomer composition specified by /i(= 1 —/2) is readily calculated from Eq. (8) if the monomer reactivity ratios ri and V2 are known. Again it is apparent that the mole fraction Fi in general will not equal /i hence both /i and Fi will change as the polymerization progresses. The polymer obtained over a finite range of conversion will consist of the summation of increments of polymer differing progressively in their mole fractions F. ... 

For esterification with an equimolar initial mixture of reactants, the mole fractions of the components in the reaction mixture are the following functions of conversion ... 

No significant changes in conversion and in mole fractions are observed if iterations are continued. The mole fractions of water and ethyl acetate are now very close to the experimental data. 

For a well-mixed flow system at steady state, the fractional conversion Xa is the ratio of the number of moles of A converted to the moles A fed to the system... 

Cross-sectional area Volumetric flow rate Reaction rate Stoichiometric constant Molar flow rate Molar feed flow rate A Molar feed flow rate B Molar inert flow rate Pressure Gas constant Temperature Fraction conversion Mole fraction Length... 

Once the mole fraction of acetic acid has been obtained, calculation of the conversion is then trivial, and we have defined the extent of conversion at a given time t, X(t), as ... 

Table 6.14 Equilibrium conversions and product mole fractions for the manufacture of hydrogen.

The liquid stream can readily be separated into relatively pure components by distillation, the benzene taken off as product, diphenyl as an unwanted byproduct and the toluene recycled. It is possible to recycle the diphenyl to improve selectivity, but it will be assumed that is not done here. The hydrogen feed contains methane as an impurity at a mole fraction of 0.05. The production rate of benzene required is 265 kmol-lr1. Assume initially that a phase split can separate the reactor effluent into a vapor stream containing only hydrogen and methane, and a liquid containing only benzene, toluene and diphenyl, and that it can be separated to produce essentially pure products. For a conversion in the reactor of 0.75,... 

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