Stainless steel header keeps the water flowing
March 1st 2008

When BP's ion exchange plant showed signs of failure, Elga Process Water provided the engineering repairs.

BP's Hull site manufactures acetic acid and various other chemicals. Its integrity was threatened when its water treatment plant, M186, began to corrode, threatening the availability of a continuous supply of water to the site's steam generators.

The water treatment plant, which consists of three 140m3/h streams, each with weak and strong acid cation exchangers, a common degasser and weak and strong base anion exchangers, provides feed water to the factory's 64 and 45barg steam boilers.

BP explains that the strong acid cation exchange units were backwashed on an infrequent basis, however the collector systems were not adequately supported and there was enough movement to damage the rubber coating. This allowed regenerant acid to attack the carbon steel underneath resulting in corrosion and failure of the collector header to vessel manifold joint with a resultant escape of resin, ineffective regeneration and eventually leading to total failure of the units.

BP Works Engineering planned to retrofit new collectors. They installed supports in the pressure vessels and fitted stainless steel nozzles on the SAC shell for connection to the collector system. ELGA Process Water fabricated a stainless steel header with laterals in stainless steel wedge wire.

BP says the modified internals have performed well, with good distribution of the regenerant acid.

Reliability has improved and there have been no further problems.

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