Gunns Ltd Pulp Mill Project

Transcription

1 Gunns Ltd Pulp Mill Project Gas Pipeline Lateral & Station DESIGN BASIS DOCUMENT Document No. HPGJ005-GP-DBD Prepared by: Hargrave Pipeline Group Pty Ltd A.B.N Rosevears Drive, Rosevears Tasmania 7277 Tel D 03/04/06 Map of Pipeline Route revised TGH AH AH C 07/01/06 Freehills comments incorporated AH AH B 19/12/05 Issued for comment AH AH A 26/04/05 Issued for comment AH AH Rev Date Description Prepared Checked Approved Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 1 of 20

2 Table of Contents 1 PROJECT REQUIREMENTS Summary of Project Easement & Alignment Sheets Environmental Management Plan Pipeline & Station Risk Assessment HAZOP PIPELINE OPERATION Pressure Control Gunns Lateral Odorant Meter & Regulator Stations Pipeline Control System PROCESS DESIGN Gas Quality Site Analysis Equipment Hydraulics & Capacities Design Pressures DESIGN OF PIPELINE Standards Pipeline Documents Pipeline Data Geotechnical Conditions Pipeline Materials & Coating Pipeline Coatings Cathodic Protection Mitigation of AC Effects and Lightning Fencing Markers Marker Tape Fracture Control Plan Road Crossings River and Stream Crossings Crossing or Parallel with Third Party Services Pipeline Valves & Piping Station Pipeline & Piping Launcher & Receiver Pipeline Valves Pipeline Insulation Joints Civil Works Site Dimensions Equipment Huts Foundations Structural Support Pipeline & Piping Non-Destructive Testing Coating Testing Hydrostatic Testing Commissioning Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 2 of 20

3 5 METER and PRESSURE REDUCTION STATIONS Design Standard Station Components Filtration Metering Composition and Energy Measurements Heating Pressure Reduction Site Requirements INSTRUMENT AND ELECTICAL Field Instruments and Cabling Power Supplies Electrical Installation Site Lighting Hazardous Areas Earthing Lightning Protection Security Monitoring DATA MONITORING SYSTEM...19 Appendices...20T Disclaimer This report has been prepared on behalf of and for the exclusive use of Gunns Limited and is subject to and issued in accordance with the agreement between Gunns Limited and Hargrave Pipeline Group Pty Ltd. Hargrave Pipeline Group Pty Ltd accepts no liability or responsibility whatsoever for it in respect of any use of or reliance upon this report by any third party. Copying this report without the permission of Hargrave Pipeline Group Pty Ltd is not permitted. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 3 of 20

4 1 PROJECT REQUIREMENTS 1.1 Summary of Project Gunns Limited proposes to establish a Pulp Mill at Bell Bay in Tasmania. The Bell Bay Pulp Mill will require a natural gas supply for its recovery boiler, power boiler, NCG boiler and its Lime Kiln. It is proposed to design and construct a high pressure natural gas pipeline lateral from the Alinta Bell Bay Meter station to the Gunns Pulp Mill site. The Pulp Mill site will be located approx. 3 km south of the Bell Bay meter station along the Tamar River. This document sets out the minimum requirements for the design and construction of a high pressure natural gas pipeline and pressure reduction station. 1.2 Easement & Alignment Sheets During construction, an easement of 20m wide is required over the pipeline route. The easement width may be reduced at certain locations, and may be enlarged at pipeline facilities. The pipeline location can be adjusted, subject to cultural heritage and environmental clearance. The same easement will accommodate both the gas pipeline and effluent pipeline. For preliminary maps of the easement, refer A. Alignment sheets will be prepared for the project during detailed design, which will define as a minimum the easement location and width, pipe wall thickness, pipeline length, river / road crossings, depth of cover. 1.3 Environmental Management Plan The APIA Code of Environmental Practice will be used as a basis for this study and detailed engineering. An environmental management plan will be prepared for detailed design, construction and operation of the pipeline in accordance with environmental approvals for the project. 1.4 Pipeline & Station Risk Assessment The pipeline design shall be subject to a risk assessment in accordance with AS The risk assessment process will be undertaken and documented using a database, with integration to the GIS and alignment sheets. The risk assessment will be formally reviewed in a workshop environment, and design related corrective actions implemented prior to commencement of construction. The risk assessment will be approved prior to construction. Formal risk assessment reviews will be undertaken prior to commissioning (to ensure that all identified management procedures are implemented) and following completion of the pipeline. The risk assessment will address all components of the pipeline, including pipeline stations. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 4 of 20

5 1.5 HAZOP A formal HAZOP shall be conducted covering modifications at the Alinta Bell Bay Meter Station and for the Gunns meter and pressure reduction station. All changes to the Piping & Instrument Diagrams (P&IDs) after the HAZOP shall be examined in a follow-up HAZOP conducted towards the end of the detailed design process. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 5 of 20

6 2 PIPELINE OPERATION 2.1 Pressure Control Gunns Lateral Flow from the Tasmanian Gas Pipeline (TGP) into the Class 600 Bell Bay to Gunns Pulp Mill pipeline lateral will be controlled by a pressure limiting valve. This valve will be an addition to the existing Bell Bay Meter Station pressure limiting valve that supplies the TGP Southern Pipeline Extension to Hobart. The control valve will be provided with a control loop that will incorporate a maximum adjustable set point to limit the pressure to the Maximum Available Operating Pressure (MAOP). Should the pressure entering the pipeline lateral exceed MAOP, the existing Bell Bay Meter Station Mainline Valve will close via a high pressure switch and an alarm will display. Downstream of the additional pressure limiting valve will be the filtration and metering plant. The gas will then flow into the pipeline lateral, which is approx 3 km in length, to a pressure reduction station located in the Pulp Mill site. The 3 km pipeline lateral will enable Gunns to have sufficient line pack should maintenance be required at the Bell Bay Meter station or should the mainline valve due to an emergency. Stable and continuous gas supply is critical, and the high pressure lateral and addition of a pressure limiting valve will ensure continuity along the Gunns lateral. 2.2 Odorant The TGP has odorant injection at Victoria and is continually odorised. The pipeline lateral will become odorised once gas is introduced into the Gunns pipeline lateral. However, low levels of odorant will be recorded initially, and continuous gas flow will stabilise the recorded levels. 2.3 Meter & Regulator Stations The existing Bell Bay Meter Station will require flow filtering and metering for the proposed gas pipeline lateral. The Gunns Pulp Mill site shall have heating, pressure reduction and pressure protection systems. Refer B for Process Flow Diagrams (PFD s) for further details. 2.4 Pipeline Control System The Gunns pipeline lateral will receive gas from the Bell Bay Meter Station. The pipeline will be remotely monitored and controlled from a Control Centre. Relevant process data, equipment status, and control signals will be transmitted to/from a Telemetry Unit located in the station equipment hut at site through a data communications system. The process data from the site will include pressure, temperature, valve status, valve open/close, site security and cathodic protection potential and current. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 6 of 20

7 3 PROCESS DESIGN 3.1 Gas Quality Site Analysis Equipment A site Gas Chromatograph provides gas analysis of the gas composition, heating value, specific gravity and wobbe index. Refer to D for typical gas composition. 3.2 Hydraulics & Capacities Design Pressures The design pressure for mechanical design of the Gunns pipeline lateral (MAOP) is 10.2 MPa for the approx 3 km length of the pipeline. The minimum delivery pressure assumed for hydraulic calculations is 6 MPa. For natural gas usage, refer to C. Refer to D for a set of preliminary modelling calculations for varying flows and capacities at differing pressures. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 7 of 20

8 4 DESIGN OF PIPELINE 4.1 Standards The pipeline design shall be in accordance with the requirements of AS 2885, and its referenced standards. Piping within Meter/Regulator Stations shall be designed to AS Pipeline Documents As a minimum, the following documentation for the design and construction will be prepared during the design stages; Pipeline Hydraulic calculations Meteorological Design parameters Pipeline material specification Pipeline Fracture control Plan Pipeline Risk Assessment Pipeline Construction Specification Pipeline Road crossing calculations Pipeline Wall Thickness calculations 4.3 Pipeline Data Pipeline Design Code AS 2885 Seismic Design Code AS 1170 Class 600 Service Fluid Treated Natural Gas Location Class as per AS 2885 R1 & T1 Design Life 25 years Design Pressure (MPag) 10.2 Design Temperature ( o C) above ground (max/min) 60 C / -10 C below ground 0 (min) Size / Outside / Diameter (mm) Material API 5L X65 (To be confirmed) Wall Thickness 4.8 mm and or 7.9 mm Installation Buried Minimum Depth of Soil Cover (mm) 750 (Note.1) Onshore Length (m) 3,000 (approx.) External Coating 0.4mm Fusion Bonded Epoxy (FBE) or 1.15 mm 2 layer HDPE (Yellow Jacket) Internal Coating Nil Field Joint Coating Compatible with External Coatings Cathodic Protection Sacrificial Anode Notes 1. At road and water crossings, the soil cover shall be increased to a minimum of 1200 mm to account for heavy loads at road crossings and soil cover erosion at water crossings Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 8 of 20

9 4.4 Geotechnical Conditions A geotechnical survey will need to be undertaken to characterise soils along the length of the pipeline route. The geotechnical survey will: Identify locations where special pipeline design is required Characterise soils by type. Characterise soils by their excavation characteristics. The outcome of these geotechnical evaluations will be important to finalise the detailed design of the pipeline. However, geotechnical conditions rarely prevent the construction and operation of gas pipelines and are not expected to in this case. 4.5 Pipeline Materials & Coating Pipeline The pipeline material described in the Table below will comply with the requirements of API Specification 5L. The grade and wall thickness will satisfy pressure containment, fracture control, external load and risk assessment requirements. Pipeline Size Grade Description Wall Thickness DN 150 API 5L Grade X42 Std Wall 6.4 mm OR DN 150 API 5L Grade X65 Std Wall 4.8 mm API 5L Grade X65 Heavy Wall 7.9 mm Coatings The DN 150 pipeline will be coated with either Fusion Bonded Epoxy (FBE) or HDPE (Yellow Jacket), and field joints coating shall be coated with a compatible coating. The station pipe, valves, fittings and steelwork in general shall be coated in the factory in accordance with an approved painting specification. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 9 of 20

10 4.6 Cathodic Protection The pipeline will be protected from corrosion by a cathodic protection system. The cathodic protection will be designed and installed in accordance with AS All equipment which is earthed will be isolated from the pipeline so that the cathodic protection is unaffected by the earthing. The Tasmanian Electrolysis Committee will be kept informed of the progress of the design of the cathodic protection systems, and all necessary documentation will be prepared and interference testing will be carried out in accordance with AS Mitigation of AC Effects and Lightning The length of the pipeline will parallel high voltage overhead power lines. The effect of the proximity of the power lines may be to: Create personnel safety hazards during construction. These hazards will be mitigated by appropriate work-safe practices. Induce high levels of AC in the pipeline under power line operating and fault conditions. Calculations during the design stage will be carried out to determine the magnitude of the exposure to electrical fields from the power line, and to design appropriate mitigation to reduce the exposure to safe levels for personnel and equipment and comply with AS/NZS The pipeline for this stage of the project is 50 meters away from the closest HV power line, and the required data to complete the study is listed in E. The pipeline, test points, pipeline earthing features, and other equipment will be located remote from the power line earths to prevent the hazards of electrical fields around power line earthing. Mitigation design shall comply with the requirements of AS/NZS Lightning protection devices will be installed to mitigate lightning effects across insulating joints and other cathodic protection equipment. 4.7 Fencing Sites shall be fenced with galvanised chain link topped with three-strand barbed wire leaning outwards. The fence, including the barbed wire protrusion, must be contained with the easement. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 10 of 20

11 4.8 Markers Pipeline markers / warning signs shall be designed and installed in accordance with AS 2885 requirements. They are required to be double sided and be located along the pipeline route as described below: Both sides of road crossings Both sides of railway crossings Both sides of significant river and stream crossings At all fences At all utility crossing (electricity, water, telecommunications, etc) At all bends Elsewhere as identified in the risk assessment. Signs are to be erected at intervals no greater than 500 m and must be within line of sight. Where the pipeline closely parallels a road or power line the spacing will be no greater than 200m. Markers shall be visible from an approach along the Right of Way (ROW) in either direction Marker Tape Marker tape is to be installed at locations identified by the risk assessment. Generally this will include open-cut trenches within road and railway reserves, and any drains or channels which may be subject to maintenance. Marker tape will be positioned at a minimum depth of 300mm below grade and a minimum distance of 450mm above top of pipe and display Gas Pipeline. 4.9 Fracture Control Plan A fracture control plan will need to be prepared before construction of the pipeline commences. It will be include critical defect length, penetration resistance and toughness of material. The data will provide a technical basis for the Pipeline licence. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 11 of 20

12 4.10 Road Crossings Road crossings will be located on the pipeline Alignment Sheets and the design of road crossings will be agreed with the responsible authority or owner. Unless otherwise required by the authority or owner, the design will meet the following requirements: Road crossings will be uncased. Concrete slabbing shall comply with AS 2885 as a minimum requirements, and be used where noted on the drawings. Pipe wall thickness shall have sufficient strength to resist external loads and be calculated in accordance with API RP In general, all crossings of sealed roads shall be bored unless a special consideration is obtained from the relevant authority River and Stream Crossings River and stream crossings shall be located on the pipeline Alignment Sheets. Depth of cover and use of heavy wall shall be determined by the risk assessment. Generally, minimum cover under permanently flowing streams shall be 1200mm. Greater cover will be required where the depth of scour is estimated to approach this level, or where there are deeper scour pockets within 100m up or downstream of the crossing location. Concrete coating shall be applied to the pipeline at open cut crossings of width greater than 10m between toes of banks, and at selected narrower crossings where there is significant risk of scour and/or erosion Crossing or Parallel with Third Party Services The pipeline shall be installed below other services except in particular cases where the risk assessment shows that it is safe to install above the other service. Clearance between the pipe and other services shall be maximised, and shall be no less than 300mm. The minimum depth of these cover requirements must be maintained at places where the pipeline crosses or is colocated with other, existing services. Marker tape shall be placed nominally 300mm below grade, and a minimum distance of 20m either side of the third party service. Where the pipeline is to share a common easement with another major utility, the preferred lateral separation shall be: High voltage power lines: 50m minimum (subject to AC interference calculations / studies) Other services: 25m The minimum separation from parallel buried services is 3 metres. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 12 of 20

13 4.13 Pipeline Valves & Piping Station Pipeline & Piping The pipeline within and adjacent to the Launcher/Receiver station shall be heavy wall, and shall extend beyond the site fence. The piping design shall limit the velocity at design flow and minimum design pressure to 20 m/s, and 15m/s at normal operating pressure, which ever is the lower Launcher & Receiver Launcher & Receiver pig traps shall be designed for cleaning, gauging, dewatering and smart pigs in accordance with AS Installation of Launcher & Receiver pig traps are optional. However, provision will be made for pig traps in the design of the pipeline Pipeline Valves The pipeline lateral will be able to be remotely isolated in an emergency by pipeline isolation valves located at Bell Bay Meter station. Detailed design will determine if a remotely isolated valve is required at the pressure reduction station. Valves shall be in accordance with the pipeline and piping specification. Valves shall be rated for 10,200 kpag (Class 600) Pipeline Insulation Joints Monolithic insulation joints will isolate the pipeline. They shall be located at the Launcher/Receivers. Supports shall not be installed between the insulating joint and the pipeline. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 13 of 20

14 4.14 Civil Works Site Dimensions Station site will be fenced nominally 20m x 65m Equipment Huts Sites will contain a small equipment hut to house power supply and electrical equipment Foundations Concrete foundation shall conform to the requirements of AS 3600 and be designed to resist the forces arising from the supported structures Structural Support Structural supports shall conform to the requirements of AS 3990 or AS Loads shall be taken from AS 1170 and from the piping or equipment being supported Pipeline & Piping Non-Destructive Testing Girth welds shall be 100% tested by X-ray radiography Coating Testing All coating and joint coatings shall be subject to holiday detection. The Direct Current Voltage Gradient (DCVG) method will be required to be performed to verify the integrity of the pipeline coating and CP system Hydrostatic Testing Hydrostatic testing of the pipeline shall be carried out in accordance with AS Launcher/Receiver stations will be hydro tested at 150% of design pressure where permitted by street calculations to AS 2885 requirements. Meter and pressure reduction stations will be tested at a pressure calculated in accordance with AS4041. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 14 of 20

15 4.16 Commissioning Commissioning of the pipeline and stations shall be carried out in accordance with an approved commissioning procedure. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 15 of 20

16 5 METER and PRESSURE REDUCTION STATIONS 5.1 Design Standard Launcher/Receiver, Meter and Pressure reduction station piping design shall comply with the requirements of AS Station Components Filtration Dry gas filter or filters shall be installed upstream of the custody transfer meters. The design of the filters will depend on the design flows and pressure. Filters shall be designed and fabricated in accordance with AS 1210 and shall remove 99% of particulates greater than 5 microns. The filters shall be registered with Workplace Standards Tasmania before operation of the pipeline Metering Custody transfer is preferred to be located at the Bell Bay Meter Station. Where two meters are required, they must be arranged in parallel (to permit removal of one unit for calibration and maintenance) with a connection to permit series operation (for check metering). Each meter run shall be provided with isolation and vent valves. Meter runs will be designed as fabricated piping assemblies and structural skid installation is not recommended Composition and Energy Measurements A Gas Chromatograph (GC) is proposed to be developed at the Alinta Bell Bay Meter Station to verify the gas quality at the pipeline receipt point Heating The gas pressure is to be reduced, and the design shall not permit the temperature of the gas downstream of the regulator to fall below 0 C during normal operation. A heater or heat exchanger will be installed at the station. Hot water supply from the mill is available for circulating hot water through the heat exchanger. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 16 of 20

17 5.2.5 Pressure Reduction Pressure reduction modules shall be provided at the Pulp Mill site to maintain set downstream pressure in response to the demand. Pressure reduction modules shall incorporate a minimum of two means of providing overpressure protection in accordance with the requirements of AS Pressure reduction at the site shall consist of a regulator with a slam shut valve upstream and another regulator/slam shut run in parallel. Should the filtration of gas be located at the Bell Bay site then in-line filters are required prior to the pressure reduction valves. 5.3 Site Requirements Sufficient land will be procured at the site to allow for future expansion of station. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 17 of 20

18 6 INSTRUMENT AND ELECTICAL 6.1 Field Instruments and Cabling Instrumentation will operate at 24 VDC. The standard analogue signal will be 2-wire 4-20mA DC, and in hazardous areas all analogue signal loops will be intrinsically safe where possible. 6.2 Power Supplies The Mill or power authority will provide a power supply to deliver a 240 VAC 50 Hz single phase supply. 6.3 Electrical Installation All power cables external to buildings will comply with Australian Standard AS Power cables integral to buildings will comply with Australian Standard AS Site Lighting Site lighting is required at the meter/regulator station. 6.5 Hazardous Areas Hazardous areas will be determined in accordance with AS and AS The most stringent of the requirements shall be implemented. 6.6 Earthing The earthing design for the site will be undertaken in conjunction with design or the pipeline cathodic protection and induced voltage protection systems. An earth grid will encompass the whole of the site and will be copper based. 6.7 Lightning Protection Lightning protection will be provided in accordance with AS Security Monitoring The site shall be fenced and shall be provided with intrusion detectors on all gates and control hut doors. On activation of any one of these proximity switches an alarm will be initiated on the SCADA system. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 18 of 20

19 7 DATA MONITORING SYSTEM The filtration and metering site at Bell Bay will be monitored and remotely controlled by an existing pipeline operator s SCADA System. The pressure reduction station will be monitored and remotely controlled by either a pipeline operating company or by the Pulp Mill SCADA System. The systems will be addressed in the design phase. Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 19 of 20

20 Appendices Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations Page 20 of 20

21 A Preliminary Map of Pipeline Route Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations

22 B Process Flow Diagrams (2 off) Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations

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24 C Natural Gas Usage Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations

25 D Gas Pipeline Capacity Calculations Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations

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53 E AC Interference - Data Requirements Gunns Ltd Pulp Mill Project DESIGN BASIS MANUAL Gas Pipeline & Stations

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