ISO9001 Boiler Spare Parts Water Wall Panels For Boiler Power Station

Materials Of Water Wall Panels

BS 3059 Grade 440 seamless carbon steel tubes.

Welding Processes / Procedures
STT II – Surface Tension Transfer (STT) Process with certified & tested weld procedures.
TIG welding process.

Fabrication Standards / National Codes
AS1228 – Power Boilers
AS4458 – Pressure Equipment Manufacture
AS4041 – Pressure Piping
AS4037 – Pressure Equipment – examination & testing

Quality Assurance Requirements
Material certification for all materials

Inspection and Test Plan (ITP)
100% radiography on butt weld joints

Advantages Of Membrane Water Wall

1). To guarantee the leakproofness of furnace wall and reduce the air leak of combustion chamber.
2). To achieve the full water cooling of combustion chamber, and the boiler accessories membrane water wall is benefit to prevent coking under the condition of supplemental firing.
3). The thermal storage capacity is small, the warming of combustion chamber is fast and the cooling is also fast, which could shorten the cooling time of boiler’s start and furnace shut down.
4). It is good to adopt top supported water cooled wall and it could reduce the load of boiler framework, which is benefit to overhang.
5) Compared with the bare tubes, the membrane water wall improves the heat absorption capacity of tubes.
6) The factory direct boiler membrane water wall could improve the Preliminary combination degree of boiler parts and reduce the installation workload.

Application Of Water Wall Panels

Boiler water walls are membrane walls that are made of tubes welded together with or without a strip of metal in between. These walls form the enclosure of the coal combustion chamber. Water wall tubes are also referred to as the evaporator section; they contain water mostly in liquid form which gradually evaporates as it rises in the boiler.

Challenges
As the water wall tubes form a lining along the whole boiler, they are submitted to a temperature gradient of 300 °C to 500 °C between the bottom section of the boiler and its top. To facilitate fitting, the panels in the boiler should preferably be made of steel grades that do not require any post-weld heat treatment. Vallourec supplies tubes for water walls in all grades, from carbon steel to advanced low-alloy steel, with outside diameters ranging from 31.8 mm to 63.5 mm.