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Cork Institute of Technology
Bachelor of Science (Honours) in Process Plant Technology
- Award
(EPPTN_8_Y4)
Autumn 2008
Process Plant Design
(Time: 3 Hours)
Instructions: Answer FIVE questions Answer at least TWO from each Section Use a separate answer book for each section
Examiners: Dr. Francis MurphySection A Mr. William Bateman Section B Mr. Joe Phelan Mr. Neil Kingston
Support Material to be provided (^) Question Location
- Steam Pipeline Sizing Chart – Pressure Drop Q6 (with paper) 2 Vapour Pressure V’s Water Temperature. Q7 (with paper)
- CIBSE Table C4.36. -Velocity press loss factors. Q7 (with paper)
- CIBSE Table C4.11 page 4-16 “Water 75 C Heavy Steel”. Q7 (with paper)
- CIBSE Table C4.11 page C4.17 “Water 75 C Heavy Steel”. Q8 (with paper)
- CIBSE Table C4.36. -Velocity press loss factors. Q8 (with paper)
Section A – Process Plant Design
Q1. Determine the reinforcement requirements for a 300 mm diameter opening in a cylindrical pressure vessel 1 m diameter subjected to an internal pressure of 5 MPa. The shell and nozzle allowable stress is 120 MPa. The shell and nozzle thickness are 25 mm and 32 mm, respectively. The reinforcement scheme is shown in Figure (Question 1) and may require extra reinforcement of thickness tp. (20 marks)
Figure (Question 1):
FORMULAE: (based on the ASME design philosophy)
The minimum required shell thickness is given by: trs = (^) S − P 0.6 R^ sP Reinforcement limit parallel to shell surface is the larger of t (^) s +t (^) n +0.5d or d. Reinforcement limit normal to the shell surface is the smaller of 2.5t (^) s or 2.5t (^) n
SYMBOLS: P = Design Pressure R (^) s = Shell Radius S = Allowable Stress d = opening diameter
Q2. (a) A pressure vessel designer generally has flexibility in selecting head geometry. Discuss the factors that make the torispherical head the most common choice. (10 marks)
Table (Question 3a): Unit strength for fillet welds
Weld Size [inches] E70 Electrode [kips/inch (kN/m)] 0.0625 0.925 (162) 0.125 1.85 (324) 0.1875 2.78 (486.9) 0.25 3.7 (648) 0.3125 4.63 (810.9) 0.375 5.55 (972) 0.4375 6.48 (1134.9) 0.5 7.4 (1296) 0.5625 8.33 (1458.9) 0.625 9.25 (1620) 0.6875 10.18 (1782.9) 0.75 11.1 (1944) 0.8125 12.03 (2106.9) 0.875 12.95 (2268)
Table (Question 3b): Fillet weld sizes
Q4. A tall tower consists of two sections. The lower section is 30 m high, 1.5 m diameter and the upper section is 20 m high, 1m diameter. The wind pressure is 1437 Pa. Modulus of elasticity (E) is 210 GN/m^2. Wall thickness of both sections is 8 mm. (a) Determine the deflection at the top of the tower. (10 marks) (b) Determine the wind moment at the base. (10 marks)
FORMULAE: Cantilever free end deflection = wl
4 8 EI ,^ Cantilever free end slope^ =^
wl^3 6 EI ,
Second moment of area of circular cross section is given by I^ =π d
4
Material Thickness Minimum Weld Size Maximum Weld Size 0.125 inches 0.125 inches 0.125 inches 0.1875 0.125 0. 0.25 0.125 0. 0.3125 0.1875 0. 0.375 0.1875 0. 0.4375 0.1875 0. 0.5 0.1875 0. 0.5625 0.25 0. 0.625 0.25 0. 0.6875 0.25 0. 0.75 0.25 0. 0.8125 0.3125 0. 0.875 0.3125 0.
Q6 a) With the aid of a neat sketch show the major components of a steam generating, steam distribution and process heating system. [10 marks]
b) Estimate the pipe diameters required to supply steam at the flow rates and pressures shown below while designing for a maximum pressure drop of 0.1 Bar / 100m pressure drop on all sections. Duplicate the table provided below on your answer book and input the relevant information required. [10 marks]
References:- Steam Pipeline Sizing Chart – Pressure Drop Q6 (with paper)
A
B
D C
E
G F I H STEAM DEMAND @ D2000kg/h @ 7 Barg 1000kg/h @ 5 BargSTEAM DEMAND @ G STEAM DEMAND @ I2000kg/h @ 2 Barg
PRESS REDUCING SET PRESS REDUCING SET PRESS REDUCING SET
EFFECTIVE PIPE LENGTHSAB - 80 m BC - 20 mCD - 10 m FG - 5 mEF - 30 mBE - 50 m^ EH - 25 mHI - 5 m
STEAM PRESSURE10 Bar g
Pipe Section
Flow kg/h
Pressure Bar g
Estimated ∅ mm
dP Bar/100m
Effective Length
Section dP Bar
Cumul dP bar
Actual Press AB BC CD BE EF FG EH HI
Q7 The following diagram shows a reactor vessel working under vacuum. Determine if the pump shown will cavitate under the operating conditions shown. [20 marks]
Water 80 Deg
PG
Pump DetailsQ=10 cubic m/h NPSHr = 2.0m
3.0 m
1.0 m
1.0 m
10.5 m8.0 m
Pressure Gauge Reading 0.5 Bar g vacuum
vessel to pump
Steel Pipe connecting Welded mild steel elbows
Vapour Pressure V’s Water Temperature. Q7 (with paper) CIBSE Table C4.36. -Velocity press loss factors. Q7 (with paper) CIBSE Table C4.11 page C4-16 “Water 75 C Heavy Steel”. Q7 (with paper)
