Page 134 - Plant design and economics for chemical engineers

GENERAL DESIGN CONSIDERATIONS 109

29. Develop a complete plant layout for the sodium dodecylbenzene sulfonate plant that
is described in Chap. 2. Indicate location of instruments, control valves, and panel
boards. Provide possibilities for future expansion or revision of the plant.
30. A synthesis gas process is described in Probs. 13 through 18 of Chap. 2. Prepare a
plant layout for a production of 25 MM scf/day which can use either air or 95
percent purity oxygen as the oxidant in this process.
31. Chlorine is transferred from a storage tank to a reactor via a vaporizer. The
vaporizer may be heated by hot water, by steam, or by closed circuit heating using a
heat transfer fluid that is inert to chlorine. The vaporizer may be a coil immersed in
a heating bath, a vertical tube bundle, a concentric tube unit, or an evaporator.
Indicate the relative merits of these different systems and select one method.
Develop a piping and instrument diagram for the system selected making certain that
all temperature, pressure, liquid level and flow control systems, and alarms are
included for safe operation.
32. Determine the utilities requirement for the nitric acid unit shown in Figs. 2-1 and
2-2. Note that the exit gas from the absorption tower is to be used for power
recovery.
33. Thrust forces caused by high-velocity, high-rate flow of fluids can cause forces of
such a nature as to damage or rupture piping and associated equipment. Consider a
S-in. schedule 40 steel pipe that rises vertically from an elbow off of a horizontal
pipe. The pipe serves as the discharge end of a pressure relief valve and must
discharge a flashing liquid/vapor mixture with an average density of 15 Ib/ft3 at a
velocity of 150 ft/s. Determine the lateral force that will be exerted on the end of
the pipe at the elbow.
34. A cylindrical tank 50 ft in diameter is used to store 10,000 barrels of liquid benzene.
To provide adequate protection during an external fire, determine the venting rate
and thevent area if the maximum tank pressure is tixed at 10 in. of water gauge. Is
the calculated vent area realistic or should the tank specifications call for a weak
seam roof? Heat transfer to the tank is by radiation from the hot soot particles and
gases in the flame and convection from the hot gases. The radiant flux emitted from
many burning hydrocarbon fuels is approximately 30,000 Btu/hr ft*. The average
accounts for fluctuations in temperature, emissivity, composition, and other variables
in the flame. Note that the tank when heated from the fire will reradiate some of the
energy it receives from the fire.
35. Obtain a copy of a patent dealing with a chemical process and outline the claims
presented in this patent. Indicate the method used for presenting the specifications,
and explain how the inventor presented proof of his or her claims.