Improved Annual Outage Execution To Extend Boiler Grate Service Life

Published Friday, August 28, 2026 3:00 pm by Morrow RS, Wannenburg E

PRESENTED: South African Sugar Technologists’ Congress Durban South Africa - August 20, 2026

Improved Annual Outage Execution To Extend Boiler Grate Service Life

Morrow RS¹ and Wannenburg E²

¹Detroit Stoker Company, Monroe, Michigan USA                                               

²Babcock Ntuthuko Engineering, Gauteng, South Africa

Abstract

Babcock Ntuthuko Engineering, which is part of the African operations of the Babcock International Group, and the Detroit Stoker Company have a combined 260 years of experience in the design, fabrication, operation and maintenance of grate-fired combustion systems that serve the industrial boiler market, and they have a significant presence in the sugar industry.

This paper presents a collaborative approach to the planning and execution of annual field inspections and outages for bagasse and coal-fired grate combustion systems. The topics include project management considerations, such as scope development, scheduling, safety planning, labour coordination and equipment requirements. The discussion also addresses the common outage complexities that arise from concurrent boiler maintenance activities, including the erection of scaffolding, pressure-part repairs, refractory work, as well as the potential of providing temporary electrical power in case mill power is interrupted. The emphasis is placed on the importance of cold operational testing and the initial start-up procedures, to ensure reliable post-outage operation.

In addition to outage execution, the paper examines inspection practices for the major wear components that are associated with a Detroit RotoGrate® spreader-type travelling grate system. The key components that are discussed include grate bars, grate chains and grate support rails. The evaluation criteria focus on individual components fit and function, with specific attention being given to the wear limits, physical distortions and high-temperature corrosion mechanisms. In addition, the operational practices that influence component degradation are reviewed, and recommendations are provided to mitigate their wear and to extend their service life.

The intention of the information that is presented is to support maintenance planning, to improve outage execution and to enhance the long-term reliability of bagasse- and coal- fired grate systems.