Economizer Coil Replacement Project (ECO)

Project location: Austria

Contractor: PRO-Welding Industry Services – team of 13 certified specialists

Scope of work: Comprehensive replacement of 28 double economizer (ECO) coil assemblies connected by two headers, located at level 6 of the facility. The works were carried out in a two-shift system, with simultaneous execution of assembly works, welding operations, and additional tasks resulting from ongoing technical condition assessments of the installation.

PRO-WELDING INDUSTRY SERVICES

Project Stages and Key Challenges

1. Work Organization and Preparation of the Work Front

Preparation of the logistics setup, including:

execution of access routes for the transport of old and new coil assemblies,
dismantling of a section of the ECO casing,
installation of an I-beam with a transport trolley,
installation of lifting slings and electric hoists with a lifting capacity of 1.5 t,
securing the ECO structure against positional changes during dismantling and installation works.

Due to the elevated work location, the transport of components was carried out using a crane and a specially designed transport platform extending approximately 2.5 m beyond the building outline.

2. Dismantling of Existing Coil Assemblies and Installation of New Components

As part of securing the structure, fixed support points were installed across the entire casing made of 14 mm thick steel plate, ensuring system stability throughout the works.

Installation was carried out at a rate of approximately 8–10 coil assemblies over a 10-hour period, including:

transport of components,
installation of missing stainless steel covers,
installation of safety locking mechanisms,
preparation of joints for welding (cutting to size, beveling, cleaning),
securing of the welding process.

Each coil assembly (material: P235GH, diameter: 33.7 mm, wall thickness: 4.5 mm, weight approx. 500 kg) required individual fitting, as the supplied components differed dimensionally from one another.

3. Welding Works

The welding process was carried out in parallel with the installation works. Due to the varied and restricted positions of the weld joints, welding mirrors were required in many locations.

The welding process was performed using:

three TIG welding machines with cooling units,
one MMA (stick) welding machine.

4. Additional and Repair Works

After completion of the coil installation, the PRO-Welding team additionally carried out:

installation of stainless steel covers on two ECO levels,
repairs of selected tubes,
ongoing repair works, including replacement or overlay welding of pressure tubes.