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CORK INSTITUTE OF TECHNOLOGY
INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ
Semester 2 Examinations 2010/
Module Title: Process Plant Services
Module Code: MECH
School: Mechanical Engineering.
Programme Title: Bachelor of Science in Process Plant Technology
Programme Code: EPPTE_8_Y
External Examiner(s): Mr. P. Ryan, Mr. G. Reilly
Internal Examiner(s): Ms. Maria Cullinane (Section A) Mr. Willie Bateman (Section B)
Instructions: Answer any 3 questions. All questions carry equal marks. Answer Section A and Section B in seperate answer books.
Duration: 2 hours.
Sitting: Summer 2011
Requirements for this examination: Attachments to be provided, for student reference, with this exam paper. 1 Saturated Steam - Pressure Table Q1 (with paper) 2 Steam Pipeline Sizing Chart – Pressure Drop Q1 (with paper) 3 Pressure Enthalpy Chart R22 Q2 (with paper) 4 Pressure Enthalpy Chart R717 Q2 (with paper) 5 Vapour Pressure V’s Water Temperature. Q3+4 (with paper) 6 Lowara Pump Data Sheet 04236D Q3 (with paper) 7 CIBSE Velocity pressure loss factors (2 pages) Q3+4 (with paper) 8 CIBSE Pipe Sizing Table
- Medium Grade Steel Water at 80 C (2 pages)
Q3+4 (with paper)
Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination paper. If in doubt please contact an Invigilator.
Section A – Steam & Refrigeration
Q1 a) Sketch and label a basic steam system schematic [3 Marks]
b) Why does TDS build up inside a steam boiler? What negative effects can high TDS have on boiler operation? How are TDS levels controlled within a steam boiler? [5 marks]
c) Calculate the size (tonnes/hour) of boiler required to heat a 25m^3 tank of water from 10oC to 70 oC in 1 hour. The boiler will be located 165m from the water tank and will run at 8 bar gauge. Assume that the steam is 90% dry. The specific heat capacity of water is 4.18kJ/kgK. The maximum permissible pressure drop for the steam line is 0.3bar/100m. Size the pipe-work needed to supply the required steam. [12 Marks]
Additional information:
Q E mCp T
Actual hfg = (dryness factor) x hfg Add 10% additional length to pipe lengths over 100m to allow losses due to pressure drop. Allow 3.5% steam losses per 100m of pipe length due to heat losses and condensation.
L = 165m
Section B – Pipe work systems.
Q3 a) The following diagram shows an open tank positioned below the suction of the pump. Determine if the pump shown will cavitate under the operating conditions shown. Show all calculations. [14 marks]
All valves are globe valves
0.4 m
Q = 9000 Lit/hr
4.2 m 1.8 m
Water 80 Deg
PG
Pump Details Lowara HTF4 32- Data Sheet 04236D
3.0 m
1.0 m
Pressure Gauge Reading 0.5 Bar g vacuum
vessel to pump
Steel Pipe connecting
Welded mild steel elbows
b) As the designer of an unspecified pumping system, your calculations have shown that cavitation is likely to occur at the suction of the pump. List and explain four possible actions you could suggest to reduce the likelihood of cavitation. [6 marks]
Reference - Vapour Pressure V’s Water Temperature. Q3+4 (with paper) Lowara Pump Data Sheet 04236D Q3 (with paper) CIBSE Velocity pressure loss factors (2 pages) Q3+4 (with paper) CIBSE Pipe Sizing Table
- Medium Grade Steel Water at 80 C (2 pages)
Q3+4 (with paper)
Q4 A pump and pipe work is required to transfer 90000 l/h of water to one of three points on T1003, T2002 or T3007. Only one route is enabled at any one time. The pipe work is stainless steel. However no CIBSE pipe sizing tables exist for stainless steel. Then use CIBSE pipe sizing tables for medium grade steel pipes and fittings. Use all welded joints. (a) Which of the three possible routes will be the index run. Justify your selection by comparing the relevant factors that contribute to the total pressure drop along each run. [4 marks] (b) Estimate the pipe diameter for each section of pipe. [2 marks] (c) Specify overall flow and pressure requirements for the pump. [14 marks]
CIP SYSTEM PIPE SIZING EXERCISE
4,2 m
3,2 m
NOTES
of 3m/s for CIP systems.
To facilitate agressive washing of pipes + PHE use a target water flow
at inlet to spay ball
CIP spray ball T residual pressure of 1 bar
Use CIBSE Charts for Mild Steel
No CIBSE Charts for SS.
on all pipe runs.
Stainless Steel Pipe work
at any one time A. T1003 CIP nozzle. B. T2002 CIP nozzle. C. T3007 Spray Ball.
Only one route in use
Pumped Volume Q=90,000 l/h Water at 80 Deg C
i.e from pump to one of
on all pipe runs
All valves are actuated globe valves
also welded mild steel elbows
i.e. assume mild steel pipe work
at inlet to nozzle.
residual pressure of 3 bar
CIP nozzles T1003, T
at inlet to nozzle.
residual press of 1 bar
Tank 3007 CIP spray ball
at inlet to nozzle.
residual press of 3 bar
Tank 2002 CIP nozzle
at inlet to nozzle.
residual pressure of 3 bar
Tank 1003 CIP nozzle
0,4 m
(^) 2,2 m
0,4 m
0,4 m
3rd Floor^ Tank 3007
2nd Floor Tank 2002
1st Floor Tank 1003
Ground Floor
Tank G
3 m
3 m
2,7 m
P.H.E
1 m 1 m
Floor Drain
dP 1.1 Bar
Outlet
Cond Steam Inlet
1 m
Water
Reference - Vapour Pressure V’s Water Temperature. Q3+4 (with paper) CIBSE Velocity pressure loss factors (2 pages) Q3+4 (with paper) CIBSE Pipe Sizing Table – Medium Grade Steel Water at 80 C Q3+4 (with paper)
