A mixture of 75 mole% propane and 25 mole% hydrogen is burned with 25% excess ai

Question

A mixture of 75 mole% propane and 25 mole% hydrogen is burned with 25% excess air. Fractional conversions of 90% of the propane and 85% of the hydrogen are achieved; of the propane that reacts, 95% reacts to form CO and the balance reacts to form CO. The hot combustion product gas passes through a boiler in which heat transferred from the gas converts boiler feedwater into steam. a) Calculate the concentration of CO (ppm) in the stack gas. b)The CO in the stack gas is a pollutant. Its concentration can be decreased by increasing the percent excess air fed to the furnace. Think of at least two costs of doing so. Hint-> ( The heat released by the combustion goes into heating the combustion products, and the higher the combustion product temperature, the more steam is produced.)

Explanation / Answer

4.69 a) C3H8 + 5 O2 ? 3 CO2 + 4 H2OC3H8 + 7/2 O2 ? 3 CO + 4 H2OH2 + 1/2 O2 ? H2O Basis: 100 mol feed gas Stream 1 in (100 mol) 0.75 mol C3H8 0.25 mol H2 Stream 2 in n0 (mol air) 0.21 mol O2 / mol 0.79 mol N2 / mol Stream 1 out n1 (mol C3H8) n2 (mol H2) n3(mol CO2) n4 (mol CO) n5 (mol H2O)

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.