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Cork Institute of Technology
Bachelor of Science (Honours) in Process Plant Technology - Award
(NFQ – Level 8)
Summer 2006
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: Mr. William Bateman Mr. Joe Mason Dr. Gerry Woods Mr. Pat Hannon Support Material to be provided Question Location
- Table 7.1 Allowable Stress Table Q4 (with paper)
- Table 2.2 Welded Joint Efficiency Values. Q4 (with paper)
- Vapour Pressure V’s Water Temperature. Q7 (with paper)
- CIBSE Table C4.36. -Velocity press loss factors. Q7, Q8 (with paper)
- CIBSE Table C4.12 Page C4.16 “Water 75 C Medium Grade Steel”.
Q7, (with paper)
- Lowara Pump Data Sheet 04234D. Q7 (with paper) CIBSE Table C4.12 Page C4.17 “Water 75 C Medium Grade Steel”.
Q
- Steam Tables (college copy)
- Mathematical log book (college copy)
Section A – Process Plant Design
Q1 a) What are the factors to be considered when evaluating possible sites for a large chemical processing plant? ( marks)
b) Once the site has been selected, what are the considerations and options open to the designer in laying out the plant and the associated auxiliary systems. ( marks)
c) Describe the content and development of the drawings that will be required during the design and construction of the plant. (6 marks)
Q2 a) There are two major categories of polymer, thermoplastic and thermosetting plastics. What are the defining characteristics of the two categories and with the aid of examples illustrate their properties and uses. (6 marks)
b) What are the advantages and disadvantages of using “plastic” piping? (6 marks) c) What are the key factors to be considered when selecting a piping material? (8 marks)
Q3 a) The properties of plain carbon steels are particularly dependent on their carbon content. Explain these properties and with the aid of diagrams show how they vary with the percentage carbon. (10 marks)
b) Describe the common methods of corrosion. When designing a component how can the likelihood and severity of corrosion be reduced? (5 marks)
c) What other methods are available to the designer to minimise surface corrosion? (5 marks)
Section B – Process Plant Services.
Q5 a) Mains water or Borehole water should not be introduced directly into a steam boiler. Depending on the type of boiler and operating pressure various forms of pre-treatment are recommended. Explain briefly how boiler feed water pre-treatment can help boiler operation. (4 marks)
b) With the aid of a neat sketch describe one method of boiler feed water pre-treatment which will reduce the Total Dissolved Solids (TDS) levels entering the boiler. Describe any relevant regeneration process. (5 marks)
c) With the aid of a neat sketch show the configuration of a boiler blowdown energy recovery system utilizing a flash vessel, a heat exchanger and a deareator head. Indicate what percentage of the heat lost due to blowdown could be recovered by a flash vessel. (5 marks)
d) Calculate the percentage of flash steam generated and hence the potential energy recovery from a flash vessel operating under the following conditions. Boiler operating pressure – 10 Bar g,
- Specific Enthalpy (hf at 10 Bar g) = 782 kJ/kg. Flash Vessel operating pressure – 0.5 Bar g,
- Specific Enthalpy (hf at 0.5 Bar g) = 468 kJ/kg
- Specific Enthalpy (hfg 0.5 Bar g) = 2226 kJ/kg
- Specific Enthalpy (hg 0.5 Bar g) = 2694 kJ/kg Blowdown rate - 1111 kg/hr, (6 marks)
Q6 a) Describe with the aid of a neat sketch a typical refrigeration circuit. Label the four major components. Use arrows to indicate the direction of flow. Indicate relative pressures and liquid / gas phases after each of the four major components. (5 marks)
b) Cooling towers are often used in conjunction with large refrigeration systems. With the aid of a neat sketch show a cross section through a cross draft cooling tower showing how the water flow and return can be connected to a refrigeration system with a water cooled condenser. Label all major components. (5 marks)
c) Problems can occur due to continuous recirculation with partial evaporation of water inside a cooling tower. List two possible problems and describe the maintenance needed to prevent them. ( marks)
d) Plate Heat Exchangers and Shell and Tube Heat Exchangers are commonly used for heating and cooling of fluids. List five differences which might be considered when selecting either heat exchanger for a given application. (5 marks)
Q8 Pipe work and pump sizing. Pump and pipe work required to transfer 18000 l/h of water to one of four possible points. Only one route enable at any one time, i.e. from pump to one of following A. To bottom fill silo 1. B. To CIP nozzle silo 1. C. To bottom fill silo 2. D. To CIP nozzle silo 2. Use steel pipe and fittings. Use all welded joints. a) Estimate the pipe diameter for each section of pipe. (5 marks) b) Identify the index run and specify overall flow and pressure requirements for the pump required to transfer water along that index run. (15 marks)
Bottom Fill connection
CIP Nozzle CIP Nozzle
Bottom Fill connection
0,7 m
5,8 m
1 m
2,5 m
1 m 6 m
SILO No.1 SILO No. Only one route in useat any one time i.e from pump to one of A. Silo 1 bottom fill.B. Silo 1 CIP nozzle
Pumped Volume
D. Silo 2 CIP nozzleC. Silo 2 bottom fill. CIP nozzle requires Q=18,000 l/h at inlet to nozzle.residual pressure of 3 bar^ Water at 75 Deg C
welded mild steel elbowsall pipe runs
Mild steel pipe work on
Diaphragm valvesw/d = 1.0. For CIBSE Table C4.36.
All valves are actuated
1 m^
5,8 m
2,5 m
0,7 m
CIBSE Table C4.12 Page C4.17 “Water 75 C Medium Grade Steel”.
Q8 (with paper)
CIBSE Table C4.36. -Velocity press loss factors. Q8 (with paper)
