Analysis begins with a thermal balance between the thermal power available in the hot fumes and the expected steam generation. Once the steam generation is validated, the thermal design of the equipment is carried out. From this phase, the unit equipment is defined in terms of size, number and arrangement of tubes, material specification and type of fins required which allow the recovery boiler to operate under the established conditions and offer the required performance. A rigorous sizing model is used for this purpose including :

• Mechanical:
  • Materials and dimensions identical to those to be used.
• Process :
  • Flow rate and flue gas composition
  • Water/steam flow rate: Resulting from the heat balance.

Structural engineering included all load calculations to define the support structure for all boiler elements including access with stairs and platforms.

We performed detailed calculations to ensure the integrity and safety of the structures, adapting them to the new operational requirements.

Development of process and instrumentation diagrams(P&IDs) and process flow diagrams(PFDs) that describe in detail the instrumentation and equipment for process control.

The lists of lines, instruments, manual valves, process control valves and signal lists enables development of system control logic.

In this phase the low voltage electrical engineering is performed. Power supply to the electrical consumers is defined for equipmnet including soot blowers, sealing air fans, all motors and pumps, and lighting.

Definition and routing of power cables to serve the consumers, as well as the definition of grounding networks, switching stations and junction boxes is included.

During the civil works phase, a geotechnical study of the area where the boiler would be installed was carried out to analyze the composition of the soil strata. In the area there was an existing concrete slab and pillars, which required demolition. With the loads transmitted by the new boiler at the support points, the calculation of the new slab with the necessary pillars and the support plinths for the pumps was carried out. The works for the execution of the new slab would include excavation of the ground, backfilling with new concrete, reinforcement of existing and new and concrete pedestals to receive the structure, backfilling with gravel and replacement of the pavement.

Procurement management involved the preparation of requisitions for request for quotations (RFQs), technical-economic tabulations and the preparation of technical and economic evaluation reports.

These processes ensured the acquisition of the best equipment and services, optimizing the cost-benefit ratio.

The construction and assembly phase included the management of all subcontractors on site, namely civil works, mechanical assembly, electrical and control and instrumentation installation and thermal insulation.

Good coordination of the tasks of all subcontractors resulted in greater efficiency in the work and greater success in meeting completion dates.

Upon completion of assembly, the pre-commissioning (cold), commissioning (hot), performance testing and start-up of the new recovery boiler took place.