Material Balance with Reactions

Pure propane (\(\ce {C3H8}\)) is burnt with an excess of air to give the following analysis of combustion products in volume percent:

\(\ce {CO2}\) = 5.0, \(\ce {CO}\) = 3.5, \(\ce {H2O}\) = 11.4, \(\ce {O2}\) = 7.0 and \(\ce {N2}\) = 73.1
Calculate the percentage of excess air used.

Formaldehyde is produced by the oxidation of methane in a reactor. The following two parallel reactions occur. \[ \begin {align*} \ce {CH4} + \ce {O2} &\rightarrow \ce {HCHO} + \ce {H2O} \\
\ce {CH4} + \ce {2O2} &\rightarrow \ce {CO2} + \ce {2H2O} \end {align*} \] Methane and oxygen are fed to the reactor. The product gases leaving the reactor include methane, oxygen, formaldehyde, carbon dioxide and water vapor.

60 mol/s of methane enters the reactor. The molar flow rate (in mol/s) of \(\ce {CH4}\), \(\ce {O2}\) and \(\ce {CO2}\) leaving the reactor are 26, 2 and 4, respectively. The molar flowrate of oxygen entering the reactor is ________ mol/s.

A fuel gas consisting entirely of methane and ethane is burned with air to yield a flue gas whose Orsat analysis is 8.68 mol% \(\ce{CO2}\), 6.44% \(\ce{O2}\) and 84.88% \(\ce{N2}\). Calculate the following :

1. The analysis of the fuel in mole percent, methane = _____ , and ethane the balance.
2. The percent excess air = _______

Pure propane is burnt in an excess of air to give the following analysis of combustion products in volume percent: \(\ce{CO2} = 5.0, \ce{CO} = 3.5, \ce{H2O} = 11.4, \ce{O2} = 7.0, \ce{N2} = 73.1\). Calculate the percent of excess air used. 

Catalytic vapor-phase chlorination of carbon disulfide (\(\ce{CS2}\)) gives carbon tetrachloride: \[ \ce{CS2} + \ce{3Cl2} \rightarrow \ce{CCl4} + \ce{S2Cl2}\] The products leaving the converter analyzed 26.0 mol% \(\ce{CCl4}\), 26.0% \(\ce{S2Cl2}\), 17.5% \(\ce{CS2}\) and 30.5% \(\ce{Cl2}\). Determine the following:

1. The excess reactant ______ (carbon disulfide / chlorine)
2. Percentage excess of excess reactant _____
3. Percentage conversion of limiting reactant _____
4. kg of \(\ce{CCl4}\) obtained per kg of chlorine admitted _____

Liquid methanol (density = 792 g/L) is fed to a space heater at a rate of 12 L/h and burned with excess air. The product gas is analyzed and the following dry-basis mole percentages are determined: \(\ce{CH3OH}\) = 0.45%, \(\ce{CO2}\) = 9.03%, and \(\ce{CO}\) = 1.81%.

1. Calculate the percentage conversion of methanol ______ , the percentage excess air fed ______ , and, mole% of water in the product gas _______.
2. Calculate the molar flow rate of dry product gas (i.e., excluding water vapor) ______ mol/h, and that of water vapor ________mol/h.

Methanol is produced by reacting carbon monoxide and hydrogen. A fresh feed stream containing \(\ce{CO}\) and \(\ce{H2}\) joins a recycle stream and the combined stream is fed to a reactor. The reactor outlet stream flows at a rate of 350 mol/min and contains 63.2 mol% \(\ce{H2}\), 27.3% \(\ce{CO}\) and 9.5% \(\ce{CH3OH}\). This stream enters a cooler in which most of the methanol is condensed. The liquid methanol condensate is withdrawn as a product, and the gas stream leaving the condenser—which contains \(\ce{CO}, \ce{H2}\), and 0.40 mol% uncondensed \(\ce{CH3OH}\) vapor—is the recycle stream that combines with the fresh feed. Calculate:

1. the molar flow rates (mol/min) of \(\ce{CO}\) and \(\ce{H2}\) in the fresh feed. (i) \(\ce{CO}\) = _____, (ii) \(\ce{H2}\) = _____
2. the production rate of liquid methanol ____ mol/min
3. the single-pass conversion of carbon monoxide ____ %
4. the overall conversion of carbon monoxide ____ %

A mixture of propane and butane is burned with air. Partial analysis of the stack gas produces the following dry-basis volume percentages: 0.0527% \(\ce{C3H8}\), 0.0527% \(\ce{C4H10}\), 1.48% CO, and 7.12% \(\ce{CO2}\). The stack gas is at an absolute pressure of 780 mm Hg and the dew point of the gas is 46.5^oC. Calculate the mole% of propane in the propane-butane fuel mixture. Vapor pressure of water at 46.5^oC = 77.6 mm Hg.