Energy efficiency should be considered beyond fuel costs, with operational value, sustainability targets and the risk of outages also forming part of decision-making, industrial steam operations and project company AES MD Chris Paterson says.

“Boardrooms and boiler houses are seldom aligned, and focusing solely on managing costs can compromise efficiency and increase the risk of expensive outages. A multidimensional approach is therefore necessary,” he says.

AES commercial director Dennis Williams says companies should consider the processes involved in delivering steam for production rather than focusing only on the rand per ton of fuel delivered to site.

“This approach enables plants to use energy effectively while reducing waste, improving product quality and shortening lead times,” he says.

AES reports that it currently manages more than 75 boilers. The company says its energy-related interventions have resulted in client savings of 10% to 35%.

Its services cover boiler operations and maintenance, and projects across industries including power generation, chemicals, plastics and rubber, timber, pulp and paper, textiles, food and beverage and mining.

Remote Monitoring

AES projects director Gavin Evezard says the combination of AES’s control systems, remote monitoring and human skills has been most instrumental in helping clients to improve boiler efficiency.

“Consistent data collection and interpretation help to optimise efficiency and productivity when operating and maintaining boilers. Our remote monitoring system (RMS) is integral to effective management and safety, with control systems, remote monitoring and human intervention helping to prevent downtime, improve operational efficiency and contain costs,” he says.

The RMS platform enables AES to investigate anomalies and conduct root-cause analyses.

Two recent projects in the food processing sector demonstrate the use of data-driven decision-making. One involved replacing an outdated boiler control system and implementing load balancing across three boilers, while the other involved installing a customised control system and RMS solution with real-time monitoring, data analysis and performance tracking.

Evezard says customisation is important in South Africa, where many industrial boilers are between 30 and 60 years old. Original-equipment manufacturers may no longer have the software needed to diagnose or resolve problems, while some may operate offshore, potentially increasing the cost of solutions, he says.

“AES’s systems are developed in-house, and we have the teams, skills and access needed to diagnose and resolve problems, reducing the risk and cost of downtime,” he adds.

Despite advances in automation and control technology, human oversight remains important, particularly when solid fuels such as coal are used.

“An operator must set up and monitor the boiler according to the production facility’s requirements. Consistent human oversight reduces the risks associated with combustion and steam vessels under pressure,” Williams says.

Fluid Energy Efficiency

“Water treatment is the ‘eyes and ears’ of boiler water system health,” Williams says.

Challenges can include hard municipal water containing high levels of calcium and magnesium. These mineral deposits can resist thermal energy transfer, reducing the transfer of energy into boiler water and requiring boilers to work harder and consume more fuel.

Poor heat transfer can also increase the risk of hot spots developing on tubes, in corners, crevices and wells. Higher operating temperatures in these areas can affect boiler material metallurgy and result in tube leaks, tube failures and crack propagation.

Organic contamination is another challenge, he adds, particularly where condensate is returned for reuse and heat recovery. Organic contamination can cause foaming, which can result in priming, where water is carried over into steam lines, potentially damaging or rupturing the lines.

Williams advises that boiler water quality should be tested and closely monitored to identify potential problems so that they can be addressed before becoming catastrophic.

Redefined Energy Efficiency

Williams reports that energy efficiency is being redefined as South African manufacturers face increasing pressure to meet sustainability targets that include reducing energy consumption and carbon emissions.

Interest in waste heat recovery systems is increasing. These pressure vessels are retrofitted to recover lower-grade heat into heated water, which is then incorporated into boiler feedwater.

“Unlike economisers, which focus specifically on recovering residual heat from boiler exhaust gases, waste heat recovery boilers capture energy from multiple sources for a variety of applications,” Williams says.

AES considers factors including boiler configuration, fuel and contaminants in the flue-gas stream when assessing potential installations. The company first determines technical viability before considering the economics.

The assessment considers clients’ plant operations and processes, available waste heat streams and potential energy savings against the required capital investment.

Williams says successful implementation depends on aligning technology choices with long-term operational and sustainability goals rather than focusing solely on short-term payback.

“Using a specialist steam boiler operations and maintenance operator can help companies balance energy efficiency and optimisation. This can provide procurement and logistics capabilities, occupational and process safety protocols, and expertise in meeting sustainability goals through remote monitoring, waste heat recovery and related technologies,” he concludes.