Exercícios - Reações e Combustão - 2024-1

13.34 Benzene gas (C6H6) at 25°C, 1 atm enters a combustion chamber operating at steady state and burns with 95% theoretical air entering at 25°C, 1 atm. The combustion products exit at 1000 K and include only CO2, CO, H2O, and N2. Determine the mass flow rate of the fuel, in kg/s, to provide heat transfer at a rate of 1000 kW. 13.34 0.037 13.52 Carbon monoxide (CO) at 25°C, 1 atm enters an insulated reactor operating at steady state and reacts completely with the theoretical amount of air entering in a separate stream at 25°C, 1 atm. The products of combustion exit as a mixture at 1 atm. For the reactor, determine the rate of entropy production, in kJ/K per kmol of CO entering. Neglect kinetic and potential energy effects. 13.52 165.3 13.29 Octane (C8H18) enters an engine and burns with air to give products with the dry molar analysis of CO2, 10.5%; CO, 5.8%; CH4, 0.9%; H2, 2.6%; O2, 0.3%; N2, 79.9%. Determine the equivalence ratio. 13.33 Liquid ethanol (C2H5OH) at 25°C, 1 atm enters a combustion chamber operating at steady state and burns with air entering at 227°C, 1 atm. The fuel flow rate is 25 kg/s and the equivalence ratio is 1.2. Heat transfer from the combustion chamber to the surroundings is at a rate of 3.75 x 10^5 kJ/s. Products of combustion, consisting of CO2, CO, H2O(g), and N2, exit. Ignoring kinetic and potential energy effects, determine (a) the exit temperature, in K. (b) the air–fuel ratio on a mass basis. 13.59 Streams of methane (CH4) and oxygen (O2), each at 25°C, 1 atm, enter a fuel cell operating at steady state. Streams of carbon dioxide and water exit separately at 25°C, 1 atm. If the fuel cell operates isothermally at 25°C, 1 atm, determine the maximum theoretical work that it can develop, in kJ per kmol of methane. Ignore kinetic and potential energy effects. 13.59 8.18 × 10^5 13.71 Carbon at 25°C, 1 atm enters an insulated reactor operating at steady state and reacts completely with the theoretical amount of air entering separately at 25°C, 1 atm. For the reactor, (a) determine the rate of energy destruction, in kJ per kmol of carbon, and (b) evaluate an exergetic efficiency. Perform calculations relative to the environment of Problem 13.63. Neglect the effects of motion and gravity. Environment T0 = 298.15 K (25°C), p0 = 1 atm Gas Phase: Component ye (%) N2 75.67 O2 20.35 H2O(g) 3.12 CO2 0.03 Other 0.83