Oleum Column Flange Field Machining
CLIENT CHALLENGE
A major chemical producer required critical flange facing services on an inverted 16-inch Oleum Column Flange Nozzle and Thimble Assembly during a Turnaround (TAR) at their facility. This project presented an extreme set of challenges that prevented the use of standard field machining procedures:
- Impossibility of Removal: The client required the machining to be completed without removing the internal thimble assembly and packing material, which is a key component of the column.
- Internal Hazard: The centerline of the nozzle was actively being used to dam corrosive acid and other contents, meaning no equipment could be mounted internally.
- Dished Surface: The flange surface was significantly dished and corroded, requiring precision machining and additional stock removal as mandated by the Plant Inspection Group to ensure a perfect sealing surface.
- Extreme Safety Protocol: Due to the hazardous Oleum contents, the entire operation required technicians to work in full, cumbersome Acid Suit, Boots, and Head Gear PPE (Personal Protective Equipment).
COLT SOLUTION
Colt’s solution successfully stood out by eliminating significant client costs and downtime through a unique, safety-focused methodology.
Enhanced Safety and Planning: The process began with meticulous pre-job planning, a comprehensive HASP review, and the deployment of a dedicated, additional technician for safety watch to ensure all protocols were maintained while working in full PPE.
Unique Outside-Mount Configuration: Colt engineered and executed an outside mount for the 280-lb machining equipment. This was significantly more challenging than a typical inside mount but was necessary because the ID (Internal Diameter) had to be used to plug and dam the hazardous contents.
Precision Flange Facing: The heavy-duty machine was operated to successfully face the inverted flange, achieving the additional stock removal required by the Plant Inspection Group to eliminate the dished surface and corrosion, ensuring structural and sealing integrity.
By utilizing this outside-mount strategy, Colt provided a safe, non-invasive repair that honored the client’s critical constraint of not removing the thimble assembly.
RESULTS
Colt successfully delivered a complex, high-risk field machining facing service precisely and safely, allowing the client to maintain their critical TAR schedule.
- Direct Cost Savings: The customer realized estimated $60,000.00 in hard costs by not having to remove and re-install the stainless steel thimble assembly and associated packing material.
- Downtime Saved: Colt saved the customer several days in critical TAR downtime, accelerating the return-to-service of the column.
Colt’s commitment to safety protocol and ability to engineer a solution under extreme physical and chemical constraints provided exceptional value. This project successfully achieved the technical goals of the Plant Inspection Group while eliminating the costs, labor, and inherent risks associated with disassembling and reassembling the thimble components.
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