Methane and oxygen react in the presence of a catalyst to form formaldehyde. In a parallel reaction, part of the methane is oxidized to carbon dioxide and water: CH4 + O2 → HCHO + H2O CH4 + 2 O2 → CO2 + 2 H2O The reactor feed contains equimolar amounts of methane and oxygen. Assume a basis of 100 mol/s feed. (a) Draw and label a flowchart. Use a degree of freedom analysis based on reaction extents to determine how many process variables must be specified for the remaining ones to be calculated. (b) Derive expressions for the component flow rates of the product stream in terms of the two reaction extents, ξ1 and ξ2. (c) The fractional conversion of methane is 0.900, and the fractional yield of formaldehyde is 0.855. Calculate the molar composition of the reactor outlet stream and the selectivity of formaldehyde production relative to carbon dioxide production. Answer: 5.00 mol CH4/s; 42.75 mol HCHO/s; yCH4=0.0500; yO2=0.0275; yHCHO=0.4275; yH2O=0.4725; yCO2=0.0225.
Methane and oxygen react in the presence of a catalyst to form formaldehyde. In a parallel reaction, part of the methane is oxidized to carbon dioxide and water:
CH4 + O2 → HCHO + H2O
CH4 + 2 O2 → CO2 + 2 H2O
The reactor feed contains equimolar amounts of methane and oxygen. Assume a basis of 100 mol/s feed.
(a) Draw and label a flowchart. Use a degree of freedom analysis based on reaction extents to determine how many process variables must be specified for the remaining ones to be calculated.
(b) Derive expressions for the component flow rates of the product stream in terms of the two reaction extents, ξ1 and ξ2.
(c) The fractional conversion of methane is 0.900, and the fractional yield of formaldehyde is 0.855. Calculate the molar composition of the reactor outlet stream and the selectivity of formaldehyde production relative to carbon dioxide production. Answer: 5.00 mol CH4/s; 42.75 mol HCHO/s; yCH4=0.0500; yO2=0.0275; yHCHO=0.4275; yH2O=0.4725; yCO2=0.0225.
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