CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Semester 2 Examinations 2008/09 Module Title: Process Plant Services Module Code: MECH8018 School: Mechanical Engineering. Programme Title: Programme Code: Bachelor of Science in Process Plant Technology EPPTE_8_Y4 External Examiner(s): Mr. Neil Kingston; Mr. Joe Phelan Internal Examiner(s): Mr. Willie Bateman (Section B) Mr. John Healy (Section A) Instructions: Duration: Answer any 3 questions. All questions carry equal marks. Answer Section A and Section B in seperate answer books. 2 hours. Sitting: Summer 2009 Requirements for this examination: Attachments to be provided, for student reference, with this exam paper. 1 Steam Pipeline Sizing Chart Pressure Drop Q1 (with paper) 2 CIBSE Table C4.36. -Velocity press loss factors. Q3,Q4 (with paper) 3 CIBSE Table C4.11, Page 4-16 - Water 75 C Medium Grade Q3 (with paper) Steel. 4 Vapour Pressure V s Water Temperature. Q3 (with paper) 5 CIBSE Table C4.11, Page 4-17- Water 75 C Medium Grade Q4 (with paper) Steel. 6 Lowara HTE-HTS Series 2 Pole pumps Data Sheet Q4 (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. Page 1 of 10
Section A Steam & Refrigeration Q1 a) Compare and contrast the construction and operating characteristics of a Fire Tube Boiler with those of a Water Tube Boiler. [5 marks] b) Why is boiler feed water pre-treatment necessary? [5 marks] c) 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] d) Steam is generated at 10 Bar g pressure inside the boiler house. A new process 65m from the boiler house required 5000 kg/h at a minimum supply pressure of 9.0 bar g. Using the steam pipe sizing chart provided suggest the most suitable pipe diameter and calculate the actual pressure available at the point of use. NB design for a maximum pressure drop of 0.1 Bar / 100m. Reference :- [5 marks] Steam Pipeline Sizing Chart Pressure Drop Q1 (with paper) Q2 a). Describe with the aid of a neat sketch a typical refrigeration circuit. Label the four major components. Indicate relative pressures and liquid / gas phases after each of the four major components. [6 marks] b) Where does flash gas occur and how does it effect the fridge cycle? [4 marks] c) Draw a neat labelled sketch of a Split Unit air conditioning system, capable of heating and cooling the air conditioned space, when it is operating in cooling mode. [6 marks] d) Give a brief explanation of each of the following terms in relation to a cooling tower. Induced draught. Drift. Approach. Range. [4 marks] Page 2 of 10
Section B Pipe work systems. Q3 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 Pressure Gauge Reading 0.5 Bar g vacuum 10.5 m 8.0 m 1.0 m Steel Pipe connecting vessel to pump Welded mild steel elbows Pump Details Q=10 cubic m/h NPSHr = 2.0m 1.0 m 3.0 m Reference 2 CIBSE Table C4.36. -Velocity press loss factors. Q3 (with paper) 3 CIBSE Table C4.11, Page 4-16- Water 75 C Medium Grade Steel. Q3 (with paper) 4 Vapour Pressure V s Water Temperature. Q3 (with paper) Q4 A Cleaning In Place (CIP) pipe work system is shown on the next page. Pump and pipe work sizing required for transfer of 90000 l/h of water at 75 Deg C to one of three points on T1003, T2002 or T3007. Only one route enable at any one time. Use CIBSE Charts for steel pipe and fittings. Use all welded joints. Page 3 of 10
NOTES 0,4 m 2,2 m Stainless Steel Pipe work on all pipe runs. No CIBSE Charts for SS. Use CIBSE Charts for Mild Steel i.e. assume mild steel pipe work on all pipe runs also welded mild steel elbows All valves are actuated Diaphragm valves w/d = 1.0. For CIBSE Table C4.36. CIP nozzles T1003, T2002 residual pressure of 3 bar at inlet to nozzle. CIP spray ball T3007 residual pressure of 1 bar at inlet to spay ball Only one route in use at any one time i.e from pump to one of A. T1003 CIP nozzle. B. T2002 CIP nozzle. C. T3007 Spray Ball. Pumped Volume Q=90,000 l/h Water at 75 Deg C To facilitate agressive washing of pipes + PHE use a target water flow of 3m/s for CIP systems. Tank 3007 CIP spray ball residual press of 1 bar at inlet to nozzle. 3rd Floor Tank 3007 2nd Floor Tank 2002 1st Floor Tank 1003 1 m 0,4 m Water at 10 Deg C Tank G100 Ground Floor 0,4 m Tank 1003 CIP nozzle residual pressure of 3 bar at inlet to nozzle. 1 m Tank 2002 CIP nozzle residual press of 3 bar at inlet to nozzle. 4,2 m Cond Outlet 3,2 m P.H.E dp 1.1 Bar 1 m Steam Inlet Floor Drain 2,7 m 3 m 3 m CIP SYSTEM PIPE SIZING EXERCISE a) Estimate which route will be the index run. Without completing detailed calculations use the combined pressured drops associated with straight pipe, fittings, static head and residual head to estimate which run will be the index run. [6 marks] b) Establish the pipe diameter, pl and le for the index run. [4 marks] c) Specify overall flow and pressure requirements for the pump. [8 marks] d) Select a suitable pump from the Lowara pump data sheet attached. [2 marks] 3 CIBSE Table C4.36. -Velocity press loss factors. Q4 (with paper) 5 CIBSE Table C4.11, Page 4-17- Water 75 C Medium Grade Steel. Q4 (with paper) 6 Lowara HTE-HTS Series 2 Pole pumps Data Sheet Q4 (with paper) Page 4 of 10
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