n-Pentane is burned with excess air in a continuous combustion chamber. (a) A technician

Chapter 4, Problem 4.92

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n-Pentane is burned with excess air in a continuous combustion chamber. (a) A technician runs an analysis and reports that the product gas contains 0.270 mole% pentane, 5.3% oxygen, 9.1% carbon dioxide, and the balance nitrogen on a dry basis. Assume 100 mol of dry product gas as a basis of calculation, draw and label a flowchart, perform a degree-offreedom analysis based on atomic species balances, and show that the system has 1 degree of freedom. Interpret this result. (b) Use balances to prove that the reported percentages could not possibly be correct. (c) The technician reruns the analysis and reports new values of 0.304 mole% pentane, 5.9% oxygen, 10.2% carbon dioxide, and the balance nitrogen. Verify that this result could be correct and, assuming that it is, calculate the percent excess air fed to the reactor and the fractional conversion of pentane. Equipment Encyclopedia boiler www.wiley.com/college/felder ENVIRONMENTAL 211 WEBC04 06/04/2015 20:35:4 Page 212 (d) It was emphasized in Part (c) that the new composition could be correct. Explain why it isnt possible to say for sure; illustrate your response by considering a set of equations with 1 degree of freedom.