Digester Fabrication, Erection and Repair
Chattanooga Boiler & Tank Company routinely fabricates, erects, designs, and repairs Digesters for Pulp and Paper Mills during planned and emergency shutdowns. Chattanooga Boiler and Tank is often called upon to repair digesters because of CB&T's ability to deliver a quality product at a competitive price, and all without compromising our excellent safety record.
CB&T successfully fabricated and erected a 2205 duplex stainless steel batch digester for a Pulp and Paper mill located near Port Edwards, Wisconsin. The overall dimensions of this ASME Section VIII Pressure Vessel are 15’-6”O.D. x 44’-5” overall height. The demolition of the existing digester and the field erection of the new duplex stainless digester were completed several days ahead of the 24-day schedule the owner had requested during their 2001 fall shutdown.
CB&T utilized SMAW, SAW and FCAW weld procedures during shop and field fabrication. The owners engineer compiled a very comprehensive and demanding specification that restricted the chemical composition of the duplex stainless materials and weld consumables. The digester was constructed of 2205 duplex stainless material due to its strength and corrosion resistance. The use of duplex stainless allowed for a reduction in material thickness as well as an extension to the life of the vessel. The high alloy content of the 2205 duplex stainless material did require some changes in fabrication practice. The extensive testing performed on the project determined the weld metal phase balance to be well within the desired range both analytically and magnetically per ASTM E562. 100% (RT) X-Ray was also required by the owner resulting in a radiograph acceptance rate of 99.8%.
This is just an example of the extensive work that Chattanooga Boiler and Tank was done with Digesters for the Pulp and Paper Industry. Chattanooga Boiler and Tank designs, fabricates and erects Digesters for many industries, including the Chemical Industry and the Food Industry. Chattanooga Boiler and Tank has the ability to manufacture and erect digesters with many different types of steel plate, from stainless steel, to carbon steel, to more exotic materials, including hastelloy and inconel. This way Chattanooga Boiler and Tank can provide our customers with the perfect digester for their need.
To contact Chattanooga Boiler and Tank about Digesters or other work please send us an or telephone us at 423 266-7118.
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