Trabajo de lab

Páginas: 9 (2053 palabras) Publicado: 1 de diciembre de 2010
MASS BALANCE HOMEWORK

1) A gas containing 30% CS2, 26% C2H6, 14% CH4, 10% H2, 10% N2, 6% O2, and 4% CO is burned with air. The stack gas (combustion product) contains 3% SO2, 2.4% CO, and unknown amounts of CO2, H2O, O2, and N2. What percentage of excess air was used? a) Draw a picture of the combustion process b) Write down a set of reactions representing the complete combustion of the gas c)Determine the degrees of freedom for the system d) Adopt a convenient basis for calculations e) Write down a set of independent mass balance equations. f) Solve for all unknowns according to your choice of BC. g) Determine the percentage of excess air . 2) Methanol is synthesized from carbon monoxide and hydrogen in a catalytic reactor. The fresh feed to the process contains 32.0 mole% CO, 64.0%H2, and 4.0% N2. This stream is mixed with a recycle stream in a ratio 5 mole recycle/1 mol fresh feed to produce the feed to the reactor, which contains 13.0 mole% N2. A low single-pass conversion is attained in the reactor. The reactor effluent goes to a condenser from which two streams emerge: a liquid product stream containing essentially all the methanol formed in the reactor, and a gasstream containing all the CO, H2, and N2 leaving the reactor. The gas stream is split into two fractions: one is removed from the process as a purge stream, and the other is the recycle stream that combines with the fresh feed to the reactor. Draw a complete diagram of the process. For a basis of 100 mol fresh feed/h, calculate: 1. the production rate of methanol (mol/h), 2. the molar flow rate (mol/h)and the composition of the purge gas, 3. the overall conversion, and 4. the single-pass conversion. Briefly explain in your own words the reasons for including 1. the recycle stream 2. the purge stream in the process design.

MASS BALANCE HOMEWORK

3)

Benzene can be produced by the dealkylation of toluene following the reaction

This catalytic reaction is, however, accompanied by theside reaction

producing the undesirable by-product diphenyl. Because of this side reaction, the conversion of toluene must be kept below 100% and a series of separations with recycle of unused reactants must be instituted. In the process (shown in the picture), the reactor is feed with a stream containing 5 mol H2 per 1 mol toluene, and 75% conversion of toluene is attained. The outlet stream 6contains 5% benzene and 2% toluene. a) Perform a degree of freedom analysis for the overall process b) Establish a convenient basis for your calculations. c) Compute and tabulate all flowrates according to your choice of BC.

MASS BALANCE HOMEWORK

Liquid methanol is fed to a space heater and is burned with 60% excess air. The stack gas gives the following analysis in a dry basis:
4)

CH3OH CO2 CO O2 N2

1.76% 5.29% 1.76% 11.52% 79.6%

1. 2. 3.

Determine the fractional conversion of methanol in the process. Calculate the flow of air per mol of methanol fed to the reactor. Calculate the amount of water produced per mol of methanol fed to the reactor.

5) Propanol (CH3CH2 CH2OH) se quema con exceso de aire para producir una mezcla de gases de combustión. La alimentación alquemador consiste de 600 kg/h de propanol y 8700 kg/h de aire. Se encuentra que la conversión total del propanol es 90%. 95% del propanol se quema a través de la reacción completa y el resto a través de la reacción incompleta. Determinar: a) Estequiometría química del proceso: (4 pts) CH3CH2CH2OH + _____O2 CH3CH2CH2OH + _____O2 b) c) d) e) ____ CO2 + ____ H2O ____ CO + ____ H2O

Reactivolimitante (4 pts) Reactivo en exceso y % exceso (7 pts) La composición molar en base húmeda de los gases de combustión,% molar (8 pts) La composición molar de los gases libre de vapor de agua, % molar. (7 pts)

MASS BALANCE HOMEWORK

6) La figura muestra un diagrama de flujo para la producción de nitrato de potasio (KNO3). La alimentación fresca consiste de 850 kg/h de una solución de nitrato de...

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