Tantalum Repair to Glass Lined Reactor at Agricultural Chemicals Plant

This vessel is used in the production of agricultural chemicals. Due to market conditions the vendor supplies off-spec AHCL that contains trace amounts of fluorides in the 15-20ppm range.   Tantalum Patch in Glass Lined Reactor
The low Ph chemistry of the materials eroded a hole through the carbon steel sidewall at which time HCL was injected into the carbon steel jacket. The repair required an ASME code certified welder, the method of repair was approved by the Authorized Inspector (AI). Following the weld repair we performed a series of stress relieving procedures. This vessel had excellent glass thickness with the exception of flaws in the few areas where fluorides had attacked the glass. The initial hole was 2 ½” in diameter.  Repair work inside a 4000 gallon reactor
As a consequence of the welding repair, thermal shocked glass could be seen along the perimeter. The damaged area was approximately 7”.  Thermal Shocked Glass After Welding
Prior to the repair installation the damaged area is prepped for the installation of a tantalum repair patch.This type repair requires an 24-72hr cure cycle before the vessel can be returned to service. The standard tantalum repair is seen below. Studs are placed each 1 ¼”- 1 ½” along the perimeter of the patch. The repair is sealed along a Teflon gasket to .002” to prevent leaks.  Installing a tantalum patch inside a reactor
While Tantalum repairs effectively restore the equipment to service, they have several drawbacks. Tantalum is in very short supply for the foreseeable future with 1/3 of mining capacity recently closed. US companies are coming under increasing pressure to stop using materials originating from the conflict-zone in eastern DRC (Democratic Republic of Congo). The links below provide information on tantalum sources.
Large Tantalum patch across multiple axis'

Large Tantalum patch across multiple axis’


  

 

Enough Conflict-Free Tantalum to Meet Increasing Global Electronics Demand?

Tantalum rally continues as shortage looms 

Download “Outlook for the global tantalum market – Dec 11, 2013 (pdf)”

Global-mined-tantalum-production-1990-2009