Page 380 - Handbook of Thermodynamic Diagrams 3 : Organic Compounds C8 to C28

Appendix C

Examples for Thermodynamic Diagrams

Example 1 - Vessel Pressure

A vessel containing gaseous 1-octene (C8H16) at 230 psia and 500 F is exposed to a fire in the process
area. The temperature in the vessel is 900 F when the fire is extinguished. Estimate the final pressure in the vessel.

Since the vessel size does not change appreciably, this situation maybe approximated by a constant volume
process. Using the thermodynamic diagram, the initial volume is about 0.24 ft^3/lb. At this same volume and final
temperature, the pressure is:

P finaL_=_460_psia

Example 2 - Reactor Size

A batch reactor is to contain 2,000 Ib of 1-octene (C8H16) at 200 psia and 500 F. Estimate the reactor size.
Using the thermodynamic diagram, the volume is about 0.32 ft^3/lb at these conditions. Substitution of this
into the equation below for the reactor size provides:

Reactor Size = (2.000 1b) (0.32 ft^3/lb) = 640 ft^3

Example 3 - Process Vessel Size

A process vessel is to contain 500 Ib of 1-octene (C8H16) at 100 psia and 500 F. Estimate the process
vessel size.

Using the thermodynamic diagram, the volume is about 0.8 ft^S/lb at these conditions. Substitution of this
into the equation below for the process vessel size provides:

Vessel Size = (500 Ib) (0.8 ft^3/lb) = 400 ft^3

Example 4 - Heat Exchanger Duty

1-Octene (C8H16, 30,000 Ib/hr) at 100 psia and 500 F is heated to 900 F and then fed to a plug-flow
reactor. Estimate the heat exchanger duty necessary to accomplish the heating.

Substitution of mass flow and enthalpies from the thermodynamic diagram into the equation below provides:

Heat Exchanger Duty = mass flow (H, - H.) = (30.000 lb/hr)(47S - 200) BTU/lb

= 8.25 million BTU/hr

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