Three Oversize Metal Clamshells Completed in Only Four Weeks

KE-Burgmann UK Ltd. were contacted by Conoco Phillips Humber refinery in August 2005 as a leak had been discovered on an expander outlet expansion bellows. This is a DN2000 x 6600mm long double gimbal assembly conveying FCC flue gas at 760 degrees Celsius with each membrane compensating for both angular and axial movement.

KE-Burgmann UK immediately sent engineers to site to assess the situation and to recommend an engineering solution that did not entail shutdown of the FCCU. This was especially difficult as the external temperature of the expansion joint was upwards of 400 degrees Celsius, high-level access was required and the gimbal rings made access for fitting a clamshell extremely difficult.

After a detailed assessment of the site conditions, technical meetings with engineers on site and close liaison between KE-Burgmann UK and DK, a detailed design and method statement was presented to Conoco. This involved not one but two clamshells in order to balance the spring rate and movement forces within the assembly. The proposal was well received by Conoco and the project was scheduled to go ahead in May 2006.

During the planning of the project we were once again called to site to look at the third stage outlet expansion joint. A double hinged expansion joint DN1600 x 3000mm long again conveying Flue gas at 760 degrees Celsius located right at the top of the third stage reactor which was causing concern as the interply leak indicator suggested that the inner ply had failed. After KE-Burgmann engineers had visually inspected and tested the bellows on site it was confirmed that there was indeed inner ply failure.

Conoco once again requested an engineering solution to the same criteria above and within the same time frame. This was proposed and accepted and planned in to the May 2006 schedule.

The bellows membranes were promptly manufactured and tested in KE-Burgmann Bredan and shipped direct to the site team made up of both UK and DK welders and fitters, who were preparing the site for installation of the clamshells. The installation as expected proved very difficult with only 10mm of gap each side of the clamshell available once moved into position.

Due to the tight schedule and the highly technical nature of the project the expertise of the site team from both UK and DK was tested. This proved a very effective combination and the work was completed on schedule despite the complexity, extremely arduous working conditions and stringent safety working environment. After completion a full documentation package was supplied to enable completion of a very successful hat-trick of fitted clamshells! All completed within four weeks and most importantly to the customer’s satisfaction.

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