Methanol mass balance

For a typical one-molar methanol concentration, the electro-osmotic flux of methanol in the membrane is small as compared to the methanol diffusion. The expression for the crossover current follows from the methanol mass balance in the cell (Kulikovsky, 2002b)... 

Figure 1.7 Conversion, selectivity and mass balance for a reaction to produce methyl chloride from methanol.

A ternary mixture of mole fraction ethanol of 0.15, ethyl acetate of 0.6 and methanol 0.25 is to be separated into relatively pure products. Sketch a system of distillation columns and mixer arrangements in the triangular diagram to carry out the separation by exploiting the shift in the distillation boundary with pressure. Sketch the flowsheet corresponding with this mass balance. 

The approach of this work is to measure product compositions and mass balances in much detail in a time resolved manner and to relate this to the controlling kinetic principles and elemental reactions of product formation and catalyst deactivation. Additionally the organic matter, which is entrapped in the zeolite or deposited on it, is determined. The investigation covers a wide temperature range (250 - 500 °C). Four kinetic regimes are discriminated autocatalysis, retardation, reanimation and deactivation. A comprehensive picture of methanol conversion on HZSM5 as a time on stream and temperature function is developed. This also explains consistently individual findings reported in literature [1 4]. 

When these CCH conditions were applied to o-iodonitrobenzene (1), cr iodoaniline (2) together with iodoaniline (4) and nitrobenzene (1) were obtained in the yields indicated in Scheme 1 (88% mass balance), which corresponds to a 62% selectivity for the formation of o iodoaniline (3). Under the same conditions, the ECH of o-iodonitrobenzene (2) gave aniline (90% yield) as the sole product. There was complete hydrogenolysis of the C-I bond (no selecti vity). Thus, in basic medium (pH 12.5), CCH method is much more selective than ECH. However, in weakly acidic medium (pH 3, pyridine.HCl buffer), it has been reported that ECH at a RCu cathode in methanol-water 95 5 (v/v) gave o-iodoaniline in a 97% yield (1, 3). 

Reactions of ethanol-methanol mixtures were carried out with recovered CM catalyst at various temperatures. Several variations of the starting composition were utilized at 360°C. The results are shown in Table 1. The reaction at 310°C gave a very low conversion of the ethanol with small amounts of the higher alcohols being formed. The poor mass balance was assumed to have resulted from the formation of acetaldehyde, which was not analyzed in this experiment. 

Example 1 Reactor mass balances. The synthesis of methanol from carbon monoxide and hydrogen by the reversible reaction... 

Mass balances are to be solved for this process. Perfect separation between methanol and the reactants is assumed. Unreacted reactants are recycled to the reactor to improve their utilization. The recycle stream within the process complicates solving the mass balances, for there is a circularity in the logic of the solution. The mass balance equations must be solved simultaneously rather than singly, or solved iteratively, as is done with a spread sheet. 

A scratch pad can be very useful for a spread-sheet user. A scratch pad is an area (e.g., columns to the right of the main spread sheet) set aside for doing side calculations of parameters or constants for the main spread sheet, writing comments, locating macros, and other uses. A scratch pad would be useful in this example if the user needed mass balances for a particular product flow rate rather than a specified feed rate as just illustrated. The problem has been solved for a carbon dioxide feed rate of 100 mol/h as shown above, but suppose it is desired to know the feed rate required to produce 880 mol/h of methanol product. The problem might intentionally be solved first for a specified feed rate, because it is often more convenient to write the mass-balance equations for known process feed rates rather than known product rates. 

Substitute X2k = 7.440x10 and mp / ms = 1.053 into Equation 6.32.2 for the methanol balance. The methanol mass fraction in the exit water stream,... 

Your report should have a flowsheet and give the mass balances. Discuss the difference between the two cases and why you think one might be better. How can you find out which is more realistic Note The dipole moments of the three species are CO, 0.1 debyes hydrogen, 0 debyes methanol, 1.7 debyes (Reid et al., 1977). 

Table 8.1 Sequential Extraction Data for the Trimethylborate (TMB)-Methanol System with Methane at 0°C and 152 bar Using a Dynamic Flow Technique (Unterreiner, McHugh, and Krukonis, 1991). The weight percent of TMB in the extract is measured and the weight percent of TMB in the extraction column is calculated to within 5% from a mass balance...

Before initiating the enrichments, a nonsteady-state mass balance was performed to account for methanol stripping caused by aeration. The amount of methanol stripped over a... 

The mass balance model predicted that 28% of the methanol would be stripped over a 24-h period (one feed/decant cycle). This was verified by an average methanol decrease of 26% over a 24-h period in five replicate stripping columns constructed and operated identically to the enrichment reactors (data not shown). Based on these results, an additional 36 (xl of 99.99% methanol was added daily to the reactors along with the feed to compensate for methanol loss caused by stripping. 

A batch reactor with a cooling jacket has been chosen for the comparative studies performed in this paper. The catalyst pellets are located in a special basket. Ideal mixing of the liquid phase and a good development of the gas-liquid interface can be assumed due to the installation of a turbine stirrer and baffles. The following mass balance equations have been denved for the hydrogenation of 2,4-DNT over a palladium on alumina catalyst and performed in the batch reactor with the methanol as an evaporating solvent ... 

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