Blast tube repair for HPAL customer

One of the major repair activities of the Callidus Philippines Branch during the first quarter of 2021 was a repair of a high pressure blast tube.

 

What is a blast tube?

A blast tube is an equipment used in HPAL with severe service slurry flashing applications to safely contain and direct energy release during flashing from the let-down valve towards the bottom of the flash vessel. It is a diverging nozzle typically made of titanium and lined with Reaction Bonded Silicon Carbide (RBSC) ceramics that are mortared within titanium shroud. A blast tube is installed between the vessel nozzle and the mating flange.

 

Before blast tube repair

The scope of the repair activity was to convert the existing design of the blast tube to a new design with modified ceramic liners to improve the life cycle of the equipment as well as the equipment adjacent to it. It was the first time the Callidus repair team undertook this type of modification. The photos below show the condition of the blast tube as received for repair.

During blast tube repair

The repair activity included the removal of ceramics and mortar, a full cleaning of Titanium housing, and the insertion of a modified retaining ring at the bottom of the blast tube without removing the existing one. Then, the relining of modified ceramic liners with mortar filling.

After blast tube repair

All repair activities took place within a very tight time frame with challenges on logistics of raw materials and freight of consumables coming from Perth, WA, and USA, due to COVID-19. Risk of transmission also impacted working conditions by a reduction of manpower to comply with local government protocol, and required social distancing during all repair activities.

The Callidus team successfully relined the blast tube in these challenging circumstances, and the repaired tube was sent back to the HPAL customer’s plant site in great condition.