1. at the Ballarat City Gate Construction and Commissioning of a Shell and Tube Heat Exchanger Speaker: Godwin Wong

2. Introduction

3. © Downer Group Limited All rights reserved Gas Distribution  Supply natural gas to 633,000 customers in Western Victoria  Owns and maintains 10,500km of underground pipelines  Systems supplied using regulating stations to lower and control the pressure  The four operating pressure ranges within the distribution system are:  Transmission(Licensed Pipelines)1050 kPa –  High Pressure 2515 kPa – 1050 kPa  High Pressure140 kPa – 515 kPa  Medium Pressure15 kPa – 70 kPa  Low Pressure1.4 kPa – 2.8 kPa Page 3 AusNet Services Gas Network

4. © Downer Group Limited All rights reservedPage 4 City Gate

5. © Downer Group Limited All rights reserved Details of City Gate:  Constructed in 1978  Sole supply of natural gas to all of the Ballarat and Creswick areas  Supplied by APA’s license T57 duplicated DN300 and DN150 pipelines  Outlet of City Gate feeds into AusNet Service’s license T39 DN200 pipeline  Land owned by AusNet Services with a shared site agreement with APA Page 5 Ballarat City Gate

6. © Downer Group Limited All rights reserved Photos: Page 6 Ballarat City Gate

7. © Downer Group Limited All rights reserved Photos: Page 7 Ballarat City Gate

8. © Downer Group Limited All rights reserved Requirement for heaters at City Gates  Gas temperature drops with a reduction in pressure  Approximately 6 o C for every 1000kPa drop in pressure (Joule- Thompson effect)  Maximum drop in pressure across the regulators is around 6000 kPa which translates to a 36 o C drop in temperature  Freezing temperatures at the outlet of the regulators cause accelerated corrosion of the pipework and also renders regulators inoperable  Freezing temperatures also cause Hydrocarbon drop out  Heavier gas hydrocarbons condense to liquid which result in poor gas quality and potential damage to customer appliances Page 8 Heaters at City Gates

9. © Downer Group Limited All rights reserved Details of project:  Downer was awarded the Design and Construct contract for a shell in tube heat exchanger type heater at the Ballarat City Gate  Front End Engineering Design and full Detailed Engineering Design for the installation of the unit  Procurement, Construction and Commissioning of the heaters  Installation of new Y-style type strainers to replace the existing BS&S cartridge filters Page 9 Project Brief

10. © Downer Group Limited All rights reservedPage 10 Project Brief

11. Design

12. © Downer Group Limited All rights reserved Design Temperatures Inlet Gas Temperature8oC8oC Required outlet gas temperature (Regulator outlet)2oC2oC Maximum Gas Temperature49 o C (Regulator maximum) Page 12 Heater Design Specifications Design Pressure Maximum Inlet Pressure7,390 kPa Minimum Inlet Pressure2,000 kPa Maximum Outlet Pressure (Regulator)1,900 kPa Minimum Outlet Pressure (Regulator)1,500 kPa Design Flow Rates Maximum Site Flow Rate44,000 sm 3 /hr Minimum Site Flow Rate5,000 sm 3 /hr Maximum Site Flow Rate (heat capacity)36,000 sm 3 /hr

13. © Downer Group Limited All rights reserved Heat Exchanger  Designed and manufactured to ASME VIII  MAOP 10.2MPa  Pressure Relief Valve Boiler  Selected as per the process design  Type B Appliance Control System  Maintain a set temperature of 2oC  Temperature transducer on the outlet of the pressure regulating legs  Shut down and provide alarm to AusNet Service’s Control Room through the SCADA system Page 13 Heater Design Specifications

14. © Downer Group Limited All rights reservedPage 14 Heater Exchanger and Boiler Schematic

15. © Downer Group Limited All rights reservedPage 15 Boiler Unit Pump (Duty Pump and Standby Pump) Boiler Three Way Valve Dosing Pot Make up water tank Make up water pump Manual Balancing Valve Expansion Tank

16. © Downer Group Limited All rights reservedPage 16 Boiler Gas Fuel Line

17. © Downer Group Limited All rights reserved  Nominal Diameter 150  API 5L Grade X42  XS Wall thickness Page 17 Pipework

18. Construction

19. © Downer Group Limited All rights reserved  Civil works were completed first (concrete slabbing and conduits)  Pipework preassembled in workshop prior to being transported to site  New actuators were installed after complete installation of valves  Run A was constructed and commissioned, then Run B was constructed and commissioned  12 tonne rear mounted crane truck to remove old pipework and sling in new pipework  Hydraulic wrench used to tighten flange in accordance with flange procedure to torque values defined by gasket manufacturer  Xylan 1424 coated blue bolts Page 19 Construction

20. © Downer Group Limited All rights reservedPage 20

21. © Downer Group Limited All rights reservedPage 21

22. © Downer Group Limited All rights reservedPage 22

23. Commissioning

24. © Downer Group Limited All rights reserved Commissioning of new pipework:  In accordance with the ESV approved documentation  Nitrogen bottle G size used to leak test (100kPa)  Also to pressure test (500kPa below outlet pressure)  Pressure maintained for 30 minutes  Purge of all air before allowing gas into downstream distribution network Page 24 Commissioning

25. © Downer Group Limited All rights reserved Commissioning of Heat Exchanger  SAT in accordance with the ESV approved commissioning procedure  Tested operation of all the mechanical components (switches, valves, gauges, etc.)  Interlocks tested (indicators, shutdown and alarm) Page 25 Commissioning

26. © Downer Group Limited All rights reservedPage 26

27. © Downer Group Limited All rights reservedPage 27

28. © Downer Group Limited All rights reservedPage 28

29. Questions?