In an experimental process to study combustion, liquid n-hexane (C6H14) at 25oC is burned with air at
Question:
In an experimental process to study combustion, liquid n-hexane (C6H14) at 25oC is burned with air at 200oC. The ratio of air to fuel is carefully controlled so that no oxygen leaves in the exhaust gas. The composition of the exhaust gas on a dry basis (mole percent) is 85.61% N2 14.24% CO2 0.13% CO 0.02% C6H14 and the exhaust gas leaves at 1100oC and 1 atm.
Determine:
(a) the mass ratio of air to fuel
(b) the heat removal rate in kJ per liter of fuel (
c) the dew point of the exhaust gas, i.e., the temperature at which water vapor would first begin to condense if the gas was cooled.
In a catalytic reactor system, ethylene (C2H4) reacts with oxygen to form ethylene oxide.
2 C2H4 + O2 → 2 C2H4O
Some undesired side reactions also take place, producing carbon dioxide and water.
The reactor effluent has the following composition (on a mole basis): C2H4 = 68.3% O2 = 14.7% C2H4O = 12.2% CO2 = 2.4% H2O = 2.4%
This stream is sent to a separator where products and byproducts (C2H4O, CO2, H2O) are removed for further processing. Unreacted C2H4 and O2 are recycled back to mix with fresh feed to form the feed to the reactor.
Determine:
(a) composition of the recycle stream
(b) composition of the fresh feed
(c) single-pass conversion of ethylene in the reactor
(d) overall yield of ethylene oxide (based upon the ethylene in the fresh feed)
In the chemical recovery part of a conventional (Kraft) pulping process used to produce the wood pulp for papermaking, one processing step consists of a lime kiln where the following reaction takes place.
CaCO3(s) → CaO(s) + CO2(g)
This reaction is endothermic, and the required energy can be supplied by a combustion reaction, for example, the combustion of methane (CH4).
The inputs to a lime kiln, all supplied at 25oC, are: • 1250 kg of lime mud, consisting of 59.0 wt% solids and 41.0 wt% liquid water. The solids are 94.0 wt% CaCO3 and 6.0 wt% inerts. • Methane, CH4(g) • Air, assume dry, supplied in 20% excess
The outputs from the kiln are: • Lime, CaO(s), at 650oC • Inerts, at 650oC • O2, N2, CO2, and H2O, as gases at 200oC
Assume that the heat capacity of the inerts is the same as the heat capacity of the CaO(s), 0.28 kJ/kgoC.
Determine the methane required, in kg, if the kiln is adiabatic.
Elementary Principles of Chemical Processes
ISBN: 978-1119498759
4th edition
Authors: Richard M. Felder, ? Ronald W. Rousseau, ? Lisa G. Bullard