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 not only proven to be a worthwhile investment for the client, but has transformed its entire production process. This turnkey project, one of the largest in the sector and region, saw AES update the boiler house format, structure and technology, effectively positioning the company to meet the growing demand for affordable protein into the future.
A new era of boiler operation
AES Projects Director, Gavin Evezard believes the boilers were probably some of the oldest still operating in South Africa, prompting the new boiler manufacturer to place some of the parts in its industrial museum. “Technology has completely changed to the point where it is almost impossible to relate to the world for which that equipment had been developed,” he admits.
In today’s era of innovation and sustainability, the four new, state-of-the-art chaingrate stoker-fired firetube package boilers which were installed represent significant improvements over their predecessors. These include the latest spiral tube technology, bigger surface areas, and a secondary air system, which improves operational efficiency.
The boilers, which were commissioned earlier this year, have total steaming capacity of 63 t/h (from and at 100°C). In addition, the new technology includes an emission abatement plant to ensure less than 120 mg/Nm3 particulate emissions, an AES remote monitoring system (RMS), a de-aerator and hot well, a submerged ash conveyor system, a 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 believes that AES was awarded this extensive project due to its innovative design and management approach, and the company’s substantial experience in implementing more than 40 complex outsourced energy contracts over more than 25 years.
“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.
Steaming into the future
In addition to the age of the original boilers, there were three key drivers behind this large investment. The first was a switch from flue gas drying to steam drying to produce a better quality protein product. In the past, the company used the exhaust gases from the old boilers in the protein drying process.
The second was improving efficiency to increase production, and the third was to lower emissions in keeping with legislation to safeguard positive relationships with neighbouring communities; this was in addition to the company’s own target of decreasing carbon emissions by 50% by 2030, to reach carbon zero status by 2050.
To achieve these objectives, AES combined the new boilers with an advanced cyclone system: “The more a business is future proofed 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 capex and operational perspective,” Williams explains.
In terms of fuel source selection, the company elected to use locally sourced, cost-effective coal. AES, which is fuel-agnostic, was able to optimise the energy efficiency effectively.
“The complexity of constructing both phases of the project in parallel was like choreographing a particularly intricate dance, and presented some fairly unique challenges. The installation and commissioning of the boilers and ancillary equipment, and the boiler house itself, represented many ‘moving parts’, all of which had to be managed in accordance with tight deadlines,” Williams explains. AES played a supporting and facilitation role to ensure that all parties simultaneously delivered a successful result.
Robust results
To date, plant particulate emissions have been reduced by 42%, while the high-tech boilers and updated production process, coupled with plant upgrades and modernisation, have improved overall efficiency by at least 15%.
In addition to these impressive operations and maintenance-related metrics, Evezard says one of the most rewarding highlights of the project was upskilling of 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 concludes.
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