How infrastructure grants are cementing sustainability

Making cement uses a lot of fuel - traditionally, coal, which makes it a carbon-intensive business.

A truck delivering solid waste derived fuel to the facility

However, this ubiquitous building product is getting greener thanks to a company with a sustainable eye and grants through the NSW Environmental Trust and Environment Protection Authority (EPA).

Boral Cement Ltd, NSW’s main cement producer, slashed its coal use by up to 20% following a 2013 Major Resource Recovery Infrastructure grant co-delivered by the NSW Environmental Trust and EPA through the Waste Less, Recycle More initiative. A second grant from 2019 could see a further 10% decrease in coal by the end of 2022 – slashing coal use by up to 30% in total.

It started with a grant – 2013

Berrima Cement Works building where trucks deposit their solid waste derived fuels (SWDF) loads, and the encapsulated conveyor which feeds into the kiln’s furnaceThe Boral Berrima Cement Works in the Southern Highlands has been NSW’s main source of cement products since it opened in 1929. Now the only production kiln in NSW, Boral’s Berrima kiln supplies up to 60% of the state’s cement for our buildings, bridges, roads and more.

It traditionally fired up only with coal, reaching temperatures of 1400°C – and often around the clock. The kiln’s extreme heat fuses finely ground limestone, shale and iron into clinker ‘pebbles’, which is the basis of ‘Portland’ cement.

But in 2013 things shifted. Boral received a $4.01 million Major Resource Recovery Infrastructure grant through the NSW Environmental Trust and EPA’s Waste Less, Recycle More initiative, which funded nearly half the $9.2 million needed to design and construct new facilities that could generate energy from commercial waste. The newly built facilities now receive, transfer and control the use of waste-derived fuels in an existing cement kiln.

Boral replaced up to 20% of its coal fuel with so-called Solid Waste Derived Fuels (SWDFs), reducing carbon emissions by up to 34,000 tonnes a year. Using technology applied in European cement-making, it built a Solid Waste Derived Fuels (SWDF) receiving facility, a conveyer belt to safely transfer recycled fuel to the kiln, an in-feed system and modifications to the kiln’s exhaust system.

Award-winning environmental move

Completed in 2018, the new facility and infrastructure enabled up to 20% of the kiln’s coal needs to be replaced by recycled fuels. It now uses two types of SWDFs – Wood Waste Derived Fuel (WWDF) and Refuse Derived Fuel (RDF).

Boral’s innovative carbon reduction was recognised with the 2019 Cement Concrete Aggregates Australia (CCAA) Environmental Leadership Award for NSW and the ACT. Across the industry worldwide, replacing kilns’ fossil fuels with SWDFs such as RDF and WWDF is considered best practice sustainability.

Using SWDF fuels also helps solve waste management issues across NSW, by redirecting waste headed for landfill. As well as nearly 100% of the waste energy being recovered, the waste residues are incorporated into the end clinker product.

What’s happening now – 2019 grant

Berrima Cement Works crane grabbing solid waste derived fuelBuilding on its success in fossil fuel reduction, Boral Cement looked to further increase SWDF use. However, the build-up of gases such as chlorine from SWDFs meant it was untenable. Chlorine concentrations in the kiln’s pre-heater system could adversely affect a stable kiln, as chlorine coatings can form on the inside of pre-heater vessels, ducts and cyclones, and then become blockages.

Chloride issues mean the Berrima kiln is currently limited to using 55,000 tonnes of SWDFs each year, but a bypass could see this increase to 100,000 tonnes – meaning SWDF usage would meet more than 30 per cent of the kiln’s energy.

In December 2019, Boral Cement Ltd was awarded another Major Resource Recovery Infrastructure grant, this time for $4.68 million to fund half the cost of designing and installing a chloride bypass in the kiln pre-heater, so even more SWDFs can replace coal as fuel.

Keeping waste out of landfill, and carbon out of air

Diagram showing Berrima Cement proposed chloride bypassThe bypass solves this issue by removing chlorine from kiln pre-heater systems and returning it further downstream back to the cement-making process. This is commonly done in cement kilns around the world using high percentages of SWDFs.

An increased use of SWDFs containing biomass further reduces Berrima’s carbon emissions – as well as reducing overall waste to landfill throughout New South Wales.

The bypass is due to be operating by the end of 2022.