Tallawarra Power Station
Client
Man Hours
Manpower
Timing
Pipework
Safety
SCOPE OF WORK
Tallawarra Power Station is a state-of-the-art ‘combined cycle’ natural gas power station located on the shores of Lake Illawarra in New South Wales.
The Project commenced operation in January 2009 and is one of Australia's most environmentally efficient, large-scale gas-fired power station, emitting up to 70% less carbon dioxide emissions than traditional coal-fired power stations. With its current generation capacity of 435MW, Tallawarra Power Station generates enough power to supply up to 200,000 homes.
TWE were contracted to TENIX to supply labour for the preparation, welding and installation of three different types of pipe materials, namely Carbon steel, stainless steel and Chromemoly for the Tallawarra Power Project.
Carbon steel
Cutting, beveling and welding of carbon steel pipework is the easiest of the materials to work with. Cost for preparation and welding of this material is relatively economical.
Stainless steel
Grades 309, 316, 304 & 308 stainless steels were also welded. Due to the nature of this material, cutting, beveling and welding takes much more time than for carbon steel thus the time taken to weld is also increased.
In addition internal purging is required to prevent a atmospheric contamination. Depending on pipe diameter and length, purging can take anywhere from between 5 minutes to 8 hours.
Chromemoly
Different grades of Chromemoly such as P11, P22 and P91 were welded on the Project. This is the most difficult material to cut, bevel and weld. This material must be preheated before any welding takes place and after welding is completed the joint must be stress relieved. Stress relieving can take up from 2 to 8 hours, depending on pipe size. Chromemoly is not an easy material to weld and extreme care must be carried out as if a repair is required it’s not just a simple matter of grinding out the defect and re-welding the joint. The process of preheating and stress relieving must be carried out again. Welders understand that repairs are expensive so more time and care is required to weld the joints.
