# Problems 201 4,67. Methane and oxygen react in the presence of a catalyst to form formaldehyde. In a parallel reaction, CH4 + O2 → HCHO + H2O CH +202 CO2+2H20 methane is oxidized to carbon dioxide and water The feed to the reactor contains equimolar amounts of methane and oxygen. Assume a basis of 100 mol feed/s. (a) Draw and label a flowchart. Use a degree-of-freedom analysis based on extents of reaction to determine how many process variable values must be specified for the remaining variable values to (b) Use Equation 4.6-7 to derive expressions for the product stream component flow rates in terms of (c) The fractional conversion of methane is 0.900 and the fractional yield of formaldehyde is 0.855. be calculated. the two extents of reaction, ξι and ξ2 Calculate the molar composition of the reactor output stream and the selectivity of formaldehyde production relative to carbon dioxide production. (d) A classmate of yours makes the following observation: "If you add the stoichiometric equations for the two reactions, you get the balanced equation 2CH4+302 HCHO + CO2 +3H2O The reactor output must therefore contain one mole of CO2 for every mole of HCHO, so the selectivity of formaldehyde to carbon dioxide must be 1.0. Doing it the way the book said to do it, I got a different selectivity. Which way is right, and why is the other way wrong?" What is your response?

Question help_outlineImage TranscriptioncloseProblems 201 4,67. Methane and oxygen react in the presence of a catalyst to form formaldehyde. In a parallel reaction, CH4 + O2 → HCHO + H2O CH +202 CO2+2H20 methane is oxidized to carbon dioxide and water The feed to the reactor contains equimolar amounts of methane and oxygen. Assume a basis of 100 mol feed/s. (a) Draw and label a flowchart. Use a degree-of-freedom analysis based on extents of reaction to determine how many process variable values must be specified for the remaining variable values to (b) Use Equation 4.6-7 to derive expressions for the product stream component flow rates in terms of (c) The fractional conversion of methane is 0.900 and the fractional yield of formaldehyde is 0.855. be calculated. the two extents of reaction, ξι and ξ2 Calculate the molar composition of the reactor output stream and the selectivity of formaldehyde production relative to carbon dioxide production. (d) A classmate of yours makes the following observation: "If you add the stoichiometric equations for the two reactions, you get the balanced equation 2CH4+302 HCHO + CO2 +3H2O The reactor output must therefore contain one mole of CO2 for every mole of HCHO, so the selectivity of formaldehyde to carbon dioxide must be 1.0. Doing it the way the book said to do it, I got a different selectivity. Which way is right, and why is the other way wrong?" What is your response? fullscreen

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