The Air Quality Act, No 39 of 2004, will be used to outlaw the use of energy- intensive clamp kilns used by the brickmaking industry unless there is a transition to cleaner production, says Department of Environmental Affairs air quality management and climate change chief director Peter Lukey.
He spoke at the inauguration of South Africa’s first vertical shaft brick kiln – the SA-VSBK project, at Langkloof Bricks, in Jeffreys Bay, Eastern Cape.
Lukey said there would be increasingly enforcement of ambient air quality standards. Brick manufacturers could be expected to follow the course of the operators of Copeland reactors and mobile asphalt plants, which involved submitting appropriate phase-out plans or minimum standards for controlled emitters.
“United Nations Environment Programme action plan ‘Near-Term Climate Protection and Clean Air Benefits: Actions for Controlling Short-Lived Climate Forcers’ states that, in some regions – primarily developing countries – production of bricks and coke in traditional kilns and ovens is considered to be a likely source of significant emissions of black carbon.”
While black carbon, which is a short-lived climate forcer, is not a greenhouse gas, it is receiving increased attention. Instead of absorb- ing infrared radiation and trapping the heat in the atmosphere, black carbon warms the atmos- phere by intercepting sunlight and absorbing it.
Lukey explained that clamp kilns, especially those using poor-quality coal, fuel wood and garbage as fuel, emitted high levels of black carbon.
“Viable mitigation options include the replacement of these kilns with larger and more efficient ones, such as the VSBK and tunnel or Hoffman kilns, which require about 50% less fuel and, consequently, produce less emissions.”
The VSBK brick firing technology was made available to South Africa by the Swiss Agency for Development and Cooperation and implemented by Swiss private-sector devel- opment organisation Swisscontact and the Swiss Resource Centre and Consultancies for Development.
Langkloof Bricks executive director Nico Blake says the company decided to invest in the VSBK in 2007, as it was the most energy efficient firing technology in the world.
The Langkloof VSBK, built by Rowe Construciton, comprises six back-to-back shafts and was commissioned in August.
The continuous updraught kiln has a vertical shaft, with an unloading tunnel running through the centre of each kiln enabling access to both sides of the shaft.
“The bricks are loaded by batch at the top of the shaft. Measured amounts of coal are spread evenly between layers of the stacked bricks to control the firing temperature. The position of the fire in each shaft, in relation to the updraught, is determined by the rate at which the bricks are removed and loaded into the shaft. This enables the rising heat to be reused,” explains the SA-VSBK project team.
A full brick-firing cycle is usually completed in 24 to 30 hours.
Rowe Construction says the Langkloof Bricks design incorporates all the systems and personnel requirements for up to 18 VSBK shafts. Looking at the building, it can be seen that the snapped header course has made effective use of all the half bricks on site, ensur- ing minimal waste and cost savings.
SA-VSBK project initiator and Namakwa Stene director Kevin Fruin notes that, in South Africa, between 3.5-billion and 5-billion clay bricks are produced a year, with 80% manu- factured in clamp kilns. This accounts for 1.5% of South Africa’s coal consumption.
“Meanwhile, energy prices continue to rise and there is little scope for alternative fuels in coal-fired clamp operations, while coal is a finite resource. The Air Quality Act has also set first-time emission targets for clamp kilns, as global warming is a reality,” he says.
Swisscontact South Africa country representative Juancho Hagnauer says, if 50% of local brick production used VSBK technology, an estimated 380 000 t of coal would be saved in South Africa a year.
“This equates to 950 000 t of carbon dioxide (CO2) emissions a year, with each VSBK shaft implemented conserving 324 t of coal a year and reducing CO2 emissions by as much as 810 t. Meanwhile, emissions of other gases and particulate matter less than 10 μm will be reduced by an anticipated 90%.”
Hagnauer says the SA-VSBK Project can make a significant contribution to South Africa’s climate change migation policy, which aims to reduce carbon emissions by 32% by 2020.
Other benefits of the VSBK include improved labour efficiencies and safe working conditions, production flexibility, low breakages and increased skills levels and remuneration potential.