The following abstract provides a brief description of the Al Ghubrah Project with information regarding installation of Large Diameter Marine Intake and Outfall Pipelines, especially regarding the typical work phases: Survey, Design and Construction.
The Al Ghubrah Desalination Project is formed under the Independent Water Project Scheme in Muscat, Sultanate of Oman. The project is sponsored by Muscat City Desalination Company SAOC (MCDC); contracted to the joint venture M/s International Water Treatment Co LLC (formed by WABAG, CADAGUA, & GALFAR). The project is located approximately 20 Kms on the eastern side of Muscat city. The Intake and Outfall Pipelines are produced locally as solid wall Krah-Pipes at United Gulf Pipe Manufacturing Co LLC based in Rusyal Industrial Estate, Muscat, Sultanate of Oman.
The project highlights are as follows:
|PE 100 PIPE
Pneumatic pressure testing (0.2 bar) afterlaunching in sea
Fitted with pig entry and exit elbow for cleaning based on hydraulic performance of pipe during its operation
|PE 100 PIPE
|3||Chlorination lines||PE 100 PIPE
|1600 m||2||Installed parallel to intake pipeline|
|PE 100 PIPE
Further characteristics and details of the Al Ghubra project
Pipe design for Al Ghubrah Project
As a result of the hydraulic design under consideration of the calculated intake (5.890 m³/s) and outfall (3.657 m³/s) flow, the inner pipe diameter is chosen. The pipe material used is High Density Polyethylene (HDPE) and especially the chosen grade PE 100, guarantees perfect properties and provides the necessary durability. The wall structure has to be selected to carry all loads during installation and long-term operation.
Selected Intake Pipeline:
Buckling pressure due to Soil in trench caused will be 12.53mwc against 33.76 mwc pipe capacity.
Allowable pressure surge for pipe 6.4mwc (0.6bar), for gate operation at intake sump location.
Selected Outfall Pipeline:
The pipes are produced as Solid Wall Krah Pipe according to DIN 16961 and technical requirements of ISO 4427. The pipe wall structure is helical extruded and each layer is homogenously jointed to guarantee the required mechanical and physical properties. The highly automated pipe production process and the implemented quality system convinced every partner involved in this project.
This project shows, once again, clearly in all tests conducted in the laboratory and in handling the pipe strings at site as well, that a helical extruded Krah pipe is in all points comparable with a standard direct extruded pipe. The pressure rating is the same. In contrast to the direct extrusion method, the wall thickness for fittings or flanges can be increased easily. United Gulf Pipe Manufacturing is able to produce Krah pipes in Sultanate Oman with an ID 4000 mm.
The pipes for the Al Ghubrah Project are produced in length of 6 meters and welded to 18 meters in length before shipping to construction site.
|Hydrostatic Pressure Test in QC lab|
|Launching pipe string|
|Butt-fusion at site|
Eng. Mohammed Al Hashani
United Gulf Pipe Manufacturing
Rusayl Industrial Estate