The replacement of 78-year-old boilers at a Western Cape food processing plant, by boiler operations and maintenance service provider Associated Energy Services (AES), has proven to be a valuable investment for the client as it significantly enhanced the entire production process, says AES.

This turnkey project – one of the largest in the sector and region – saw AES update the boiler house format, structure and technology.

“Technology has completely changed to the point where it is almost impossible to relate to the world for which that equipment was developed,” AES projects director Gavin Evezard says, noting that the boilers were probably some of the oldest still operating in South Africa.

AES installed four new, “state-of-the-art” chain grate, stoker-fired, firetube package boilers, providing significant improvements over their predecessors, as they incorporate the latest spiral tube technology, bigger surface areas and a secondary air system that improves operational efficiency.

The boilers have total steaming capacity of 63 t/h – from and at 100 ºC.

Further, the new technology includes emission abatement plant to ensure less than 120 mg/Nm3 particulate emissions, an AES remote monitoring system, a de-aerator and hot well, a submerged ash conveyor system, shaftless conveyor fuel handling system and storage bunker.

In addition to providing technical management and oversight of the client’s existing steam generation plant throughout the project, AES also completed the plant layout, selection, installation, commissioning and testing.

AES commercial director Dennis Williams credits AES’s success in securing this extensive project to the company’s “innovative design and management approach” combined with over 25 years of expertise in implementing more than 40 complex outsourced energy contracts.

“Our core business is energy plant operations and maintenance, so we know how to manage a project to ensure its success in the short-, medium- and long term. We built this plant to run it, and that speaks to our overall project approach,” Evezard adds.

Improved Operation
AES explains that, in addition to the age of the original boilers, three key factors drove this substantial investment. The first was a switch from flue gas drying to steam drying to produce a better-quality protein product. Previously, the company used exhaust gases from the old boilers in the protein drying process.

The second driver was to improve efficiency to increase production, while the third driver was the need to reduce emissions to comply with regulations, maintain positive relationships with neighbouring communities and meet the company’s sustainability goals. These include a 50% reduction in carbon emissions by 2030 and achieving carbon-neutral status by 2050.

To achieve these objectives, AES combined the new boilers with an advanced cyclone system.

“The more a business is futureproofed from an environmental and emissions compliance perspective, the less issues it will have going forward, including with surrounding communities. This system delivers competitively on that critical requirement from a capital expenditure and operational perspective,” Williams explains.

The company elected to use locally sourced, cost-effective coal as a fuel source. AES, which is fuel-agnostic, was able to optimise the energy efficiency effectively.

Once the foundation slab was cast for the placement of the equipment, the boiler house structure was built around it.

“The complexity of constructing both phases of the project in parallel was like choreographing a particularly intricate dance and presented some fairly unique challenges,” Williams says.

He adds that the installation and commissioning of the boilers and ancillary equipment, as well as the boiler house itself, represented “many moving parts”, which had to be managed in accordance with tight deadlines.

AES played a supporting and facilitation role to ensure that all parties simultaneously delivered a successful result.

Robust Results
Since the completion of the project, plant particulate emissions have been reduced by 42%. Meanwhile, the high-tech boilers and updated production processes, coupled with plant upgrades and modernisation, have improved overall efficiency by at least 15%, AES says.

In addition to these impressive operations and maintenance-related metrics, Evezard says one of the most rewarding highlights of the project was upskilling the 14 boiler operators on site in the use of the new technology.

“The ancillary systems and the old boiler house were manually intensive, and the fuel and ash systems were also manually driven. Now, much less manual intervention is required,” he points out.

“Although it is very difficult to create a fully autonomous boiler system, especially one based on solid fuel firing, AES always seeks to optimise [boiler operations] so that the operational staff can concentrate on the important things – the quality of the emissions, the set-up of the boiler and the required operational efficiencies,” Evezard concludes.