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Sections 7.4-6
Steam table
Class 25
Steam Tables
•
•
•
•
Tables B-5,B-6, B-7
Superheated steam – look at p. 650
Steam is NOT an ideal gas
What’s the reference state for steam?
Liquid water is fed to a boiler at 24oC and 10 bars
and is converted at constant pressure to saturated
steam. Use the steam tables to calculate ΔH^ (kJ/
kg) for this process, and then calculate the heat
input required to produce 15,000 m3/h of steam at
the exiting conditions. Assume that the kinetic
energy of the entering liquid is negligible and that
the steam is discharged through a 20-cm ID (inside
diameter) pipe.
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10/26/10
Liquid water is fed to a boiler at 24oC and 10 bars and is converted at
constant pressure to saturated steam. Use the steam tables to
calculate ΔH^ (kJ/kg) for this process, and then calculate the heat input
required to produce 15,000 m3/h of steam at the exiting conditions.
Assume that the kinetic energy of the entering liquid is negligible and
that the steam is discharged through a 20-cm ID (inside diameter) pipe.
What is the energy balance?
Liquid water is fed to a boiler at 24oC and 10 bars and is converted at
constant pressure to saturated steam. Use the steam tables to
calculate ΔH^ (kJ/kg) for this process, and then calculate the heat input
required to produce 15,000 m3/h of steam at the exiting conditions.
Assume that the kinetic energy of the entering liquid is negligible and
that the steam is discharged through a 20-cm ID (inside diameter) pipe.
(l)/hr
a) Q = ΔU
b) Q = ΔH
c) Q = ΔU + ΔEk
d) Q = ΔH + ΔEk
e) 0 = ΔH
Liquid water is fed to a boiler at 24oC and 10 bars and is converted at
constant pressure to saturated steam. Use the steam tables to
calculate ΔH^ (kJ/kg) for this process, and then calculate the heat input
required to produce 15,000 m3/h of steam at the exiting conditions.
Assume that the kinetic energy of the entering liquid is negligible and
that the steam is discharged through a 20-cm ID (inside diameter) pipe.
(l)/hr
Liquid water is fed to a boiler at 24oC and 10 bars and is converted at
constant pressure to saturated steam. Use the steam tables to
calculate ΔH^ (kJ/kg) for this process, and then calculate the heat input
required to produce 15,000 m3/h of steam at the exiting conditions.
Assume that the kinetic energy of the entering liquid is negligible and
that the steam is discharged through a 20-cm ID (inside diameter) pipe.
(l)/hr
What is the enthalpy for the incoming water?
a)  761.5 kJ/kg
b)  762.6 kJ/kg
c)  100.6 kJ/kg
d)  2545.5 kJ/kg
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Liquid water is fed to a boiler at 24oC and 10 bars and is converted at
constant pressure to saturated steam. Use the steam tables to
calculate ΔH^ (kJ/kg) for this process, and then calculate the heat input
required to produce 15,000 m3/h of steam at the exiting conditions.
Assume that the kinetic energy of the entering liquid is negligible and
that the steam is discharged through a 20-cm ID (inside diameter) pipe.
(l)/hr
Liquid water is fed to a boiler at 24oC and 10 bars and is converted at
constant pressure to saturated steam. Use the steam tables to
calculate ΔH^ (kJ/kg) for this process, and then calculate the heat input
required to produce 15,000 m3/h of steam at the exiting conditions.
Assume that the kinetic energy of the entering liquid is negligible and
that the steam is discharged through a 20-cm ID (inside diameter) pipe.
(l)/hr
Liquid water is fed to a boiler at 24oC and 10 bars and is converted at
constant pressure to saturated steam. Use the steam tables to
calculate ΔH^ (kJ/kg) for this process, and then calculate the heat input
required to produce 15,000 m3/h of steam at the exiting conditions.
Assume that the kinetic energy of the entering liquid is negligible and
that the steam is discharged through a 20-cm ID (inside diameter) pipe.
(l)/hr
Procedure for Combined Mass & Energy
Balances
• Draw a Flow Chart
• Label all Knowns & Unknowns & follow same
procedure as for straight material balances
•  Include Phase of streams (e.g., not just H2O, but
whether l, g, v) & all information needed (T, P) for
calculating specific internal energy (U^) or
enthalpy (H^)
• Determine H^ or U^ for each component
• Determine Closed or Open System, write
appropriate energy balance equation, and
simplify
• Solve the material & energy balance equations
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A turbine discharges 200 kg/hr of saturated steam at 10.0
bar absolute. It is desired to generate steam at 250oC
and 10.0 bar by mixing the turbine discharge with a
second stream of superheated steam at 300oC and 10.0
bar. How much heat must be added?
A turbine discharges 200 kg/hr of saturated steam at 10.0
bar absolute. It is desired to generate steam at 250oC
and 10.0 bar by mixing the turbine discharge with a
second stream of superheated steam at 300oC and 10.0
bar. How much heat must be added?
What is the energy balance?
How many degrees of freedom are there?
a) Q = ΔU
b) Q = ΔH
c) Q = ΔU + ΔEk
d) Q = ΔH + ΔEk
e) Q – W = ΔH
a)
b)
c)
d)
0
1
2
3
A turbine discharges 200 kg/hr of saturated steam at 10.0
bar absolute. It is desired to generate steam at 250oC
and 10.0 bar by mixing the turbine discharge with a
second stream of superheated steam at 300oC and 10.0
bar. To generate 300 kg/hr of the product stream, how
much heat must be added?
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A turbine discharges 200 kg/hr of saturated steam at 10.0
bar absolute. It is desired to generate steam at 250oC
and 10.0 bar by mixing the turbine discharge with a
second stream of superheated steam at 300oC and 10.0
bar. If the process is carried out adiabatically, how much
product stream is generated?
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