Shell SDA project: grit-free weld-seam preparation with the Bristle Blaster®

When new IMO bunker-fuel sulphur limits pushed Shell to expand desulphurisation capacity at its Pernis refinery, the field joints on ten new process modules had to be prepared to blast-cleaning standard — without abrasive blasting. The Bristle Blaster® delivered the specified cleanliness and profile in a live, space-restricted refinery environment.

Background

The International Maritime Organization’s bunker-fuel regulations cut the allowable sulphur content of marine fuels from 3.5% to 0.5% from 2020. To adapt their refining processes, operators had to evaluate additional conversion and desulphurisation capacity. Residue gasification — especially combined with a solvent de-asphalter (SDA) unit — offered an economic route to meet the new fuel specifications.

In 2015 Shell decided to build a new SDA unit at its Pernis refinery in Rotterdam, the Netherlands, with construction planned from 2016 and completion at the end of 2018. Ten modules were fabricated for the unit.

The surface-preparation challenge

The modules were protected with thermal-spray aluminium (TSA), a coating system that demands high-quality surface preparation. During assembly and preparation of the field joints, the weld seams had to reach a cleanliness of Sa 2½ (SSPC-SP 10 / NACE No. 2) with an anchor profile of 70–110 µm Rz (2.76–4.34 mils).

Health, Safety and Environment (HSE) restrictions, together with limited working space, ruled out conventional abrasive blasting on the field joints. A grit-free method was needed that could reach the same standard in a confined, live-plant setting.

The solution

The field joints were prepared with the Bristle Blaster® Pneumatic, which generated the required cleanliness and anchor profile directly on the weld seams — no grit, no blast enclosure, and full access in restricted working space.

Results

• 10 Bristle Blaster® Pneumatic tools deployed on the SDA project.
• 2,000 weld seams prepared to Sa 2½ (SSPC-SP 10 / NACE No. 2).
• 70–110 µm Rz (2.76–4.34 mils) anchor profile achieved for the TSA coating system.
• 1,400 Bristle Blaster® belts consumed across the campaign.

Grit-free preparation let the coating crews work the field joints under HSE and space constraints that would have made abrasive blasting impractical — while still meeting the coating specification for thermal-spray aluminium.