The popularity of coal-fired boilers is slowly losing momentum to the rise in cleaner burning fuels such as natural gas, according to heat generation company Steam Generation Africa.

Steam Generation Africa MD John Rundle says gas firing is quickly gaining ground, as boiler clients realise that its impact on the environment is less, and operating efficiencies are higher, coupled with ever-increasing availability of natural gas both in the pipeline network and portable compressed gas.

Gas firing is a cleaner burning fuel, and compared to coal has no ash, resulting in less materials handling equipment to remove ash, saving on boiler house personnel costs. General maintenance costs on gas-fired boilers are considerably less than that of coal boilers, together with yearly and 36-monthly inspections.

Further, costs are saved in fuel-handling equipment, as gas is fed directly into the burner without the need of hoppers, coal bunkers and stokers that are required for coal-fired boilers.

Rundle states that the single most important part of any boiler is the burner and its combustion control system. “The future running costs of boilers depend on the choice of burner, and boiler design is worthless without the most modern burner that guarantees enhanced combustion performance.”

Steam Generation Africa is the exclusive Gauteng reseller of the UK-manufactured Autoflame Combustion Management System, which improves the air and fuel ratios in burners, enhancing their performance and efficiency.

“Clients with older-generation burners will register increased fuel efficiency of between 5% and 8%, depending on burner use,” Rundle says, adding that the management system has also been fitted successfully to locally manufactured Cyclotherm boilers.

“The patented three-parameter exhaust-gas trim system of the Autoflame system manages environmental impact, thereby reducing carbon footprint and accurately managing the combustion process,” he adds.

The company recently entered into a cooperative partnership with UK-based energy solutions company Cochran Group to sell, install and supply spare parts for their Wee Chieftan, Thermax single and twin furnaces, as well as their Borderer steam and hot-water boilers, waste-heat boilers and economisers in sub- Saharan Africa.

Rundle notes that Cochran boilers were well known in South Africa in the 1990s, when the company was owned by Rolls-Royce. However, the company withdrew from South Africa, resulting in several older-generation Cochran boilers still being used in South Africa.

Steam Generation Africa chose the Scottish brand, owing to it being “at the forefront of industry-leading innovation manufacture, robust design of boilers and construction that leads to extended operational life”, for the last 130 years.

Cochran manufactures top quality process standards and procedures that are third-party audited to internationally recognised ISO 9001, BS2790, EN12953 and ASME codes, all of which are recognised in South Africa.

The Cochran three-pass, wetback boiler is renowned for its reliability, durability and robust design, he says. Its standard working pressure is 1 000 kPa, with designs of up to 2 500 kPa available and steam outputs of 24 000 kg/h available.

“The Cochran boiler and economiser system will operate to efficiencies of up to 96%,” states Rundle.