Boiler and environmental solutions provider John Thompson, a division of electrical products supplier Actom, is now offering the sugar industry, as well as other industrial users that want to burn biomass, high-pressure mono- drum boilers.

The uncertainty surrounding power supply in South Africa is driving the need for industry to generate additional power to be brought on line within the shortest possible time; therefore, there is a need for higher-temperature and higher-pressure cogeneration boilers, says John Thompson industrial water tube boilers business unit GM Russell Warren.

“The sugar industry in South Africa did not previously need such high-pressure units but the possibility of favourable tariffs being paid for excess electricity generated is driving this industry towards higher efficiency.

“Bagasse is a by-product of the sugar- making process. This is a renewable biomass fuel and is coming under consideration for preferential tariffs,” he says.

Government is aiming to secure 3 725 MW of renewable-energy capacity from independent power producers by 2016. Of this, 12.5 MW is expected to be produced from biomass.

Warren states that the need for power and the need to reduce reliance on grid power have the potential to drive growth in the boiler industry, while the possibility of bagasse-fired boilers being considered for favourable tariffs could be an area of growth for boiler manufacturers.

He expects that, with the requirement for efficient cogeneration of power, boiler pressures within the sugar industry will increase from the current 31 bar standard up to 110 bar, depending on a company’s risk profile. Boilers of higher pressures have been installed in other industries by John Thompson.

The increase in pressure is resulting in a move away from bi-drum boilers, offered to the sugar industry in the past, to the use of monodrum boilers that offer several commercial and technical advantages over bi-drum boilers, he adds.

John Thompson’s high-pressure mono- drum boilers have been offered to the sugar industry, while boilers of similar pressures have been installed in the pulp and paper and other industries.

The monodrum boiler is best suited for cogeneration applications such as bagasse-fired boilers for the sugar industry.

Since the steam drum of the monodrum boiler is not in the hot gas stream, the unit is more robust and is less likely to suffer damage owing to low water conditions. Therefore, a thinner, more cost-effective drum can be used, says Warren.

The boiler inherently handles load swings well and it offers a fast start-up curve, thereby reducing the time from cold to steam generation. The evaporator bank is also easily maintainable.

The manufacturing of boilers takes place at John Thompson’s works in Cape Town, where the entire pressure envelope of its monodrum boilers will be manufactured.

The Cape Town facility employs about 400 people and also exports the fire- tube range of package boilers. Over 400 units have been exported over the last ten years.

Meanwhile, John Thompson last year completed a boiler project for sugar producer Illovo.

“Illovo Sugar embarked on an expansion programme at the Ubombo sugar mill, in Swaziland, which required a new 105 t/h bagasse-fired boiler to supply steam to a turbo-alternator set. Ubombo sugar is now able to export power to the Swaziland power grid and, in turn, improve the mill’s operational efficiency,” Warren points out.

The boiler was ordered in September 2009 and was commissioned and handed over in April 2011.

Industry Overview
High labour costs, imports from Chinese and Indian companies and skills shortages are significant challenges facing the boiler industry, Warren points out.

To alleviate the shortage of skilled artisans, John Thompson has embarked on an extensive apprentice training programme to meet the required labour demand. At any given point, John Thompson has about 60 apprentices in its apprentice training programme in Cape Town.

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