Sustainable Construction

Alternative Fuels

Cement-making is energy-intensive. The spiralling cost of fossil fuels over the past two decades, combined with a move towards improved environmental performance, has led the industry to turn to alternative fuels to part-replace fossil fuels, such as coal and petcoke, to heat cement kilns.

There are a number of sustainable and offer considerable benefits to the CEMEX approach, including reduced emissions and energy costs, saving valuable fossil fuels for the future and recovering energy from waste, thereby reducing the need for landfill. By cutting the burning of coal and petcoke, alternative fuels also help to reduce emissions of carbon dioxide. In doing so, they reduce climate change.   While CEMEX plants operate well within their emission limits, experience shows that performance improves further when using alternative fuels. Cement kilns operate at temperatures at which steel would melt. That, combined with the length of time which fuels spend in the kiln, means that the process releases their energy while completely and safely consuming them.

Alternative fuels have been successfully used in cement kilns for decades. In the UK, alternative fuels used include secondary liquid fuels, scrap tyres, paper, packaging and household waste, meat and bone meal and sewage sludge pellets.

ClimaFuel

Climafuel ® is a waste derived fuel which is made using household residual and commercial waste and can, therefore, substantially reduce what we send to landfill.

Climafuel ® looks like shredded paper and consists of paper, cardboard, wood, carpet, textiles and plastics. The material has been subject to a treatment process to remove biodegradable matter and produce a solid, clean and non-hazardous fuel. All recoverable materials are removed for recycling, as a result, the use of ClimaFuel significantly reduces waste sent to landfill, whilst preserving fossil fuel resources.

The fuel is manufactured to a tight specification by specialist was management companies. At CEMEX's UK cement plants it replaces 20-60% of the fossil fuels, such as coal or petcoke, currently used to heat the cement kilns, depending on the permits. Due to the biomass content of ClimaFuel, emissions of greenhouse gases are significantly reduced which improves the embodied carbon of our cement and concrete products.

Climafuel ® is produced using new technologies, such as Mechanical Biological Treatment (MBT). MBT is the umbrella term for processes that use mechanical and biological techniques to sort, separate and treat waste. The final product is a solid recovered fuel or compostable material. CEMEX is using Climafuel ® at all three of our cement plants in the UK.

Tyres

Waste derived fuels, such as tyres, have environmental benefits, such as reducing certain emissions, particularly oxides of nitrogen, and help to control production costs.

Several cement plants in the UK are already burning tyres successfully and have demonstrated that the overall environmental impact of using tyres in the fuel mix is reduced when compared with burning coal alone.

With kiln material temperatures of some 1,400 degrees centigrade there are no smells, smoke or residues from burning tyres in cement kilns. Using tyres as a waste derived fuel also reduces reliance on fossil fuels and preserves them for future generations.

In addition to the direct environmental benefits of reduced emissions, using like tyres, recovers energy from what would otherwise be considered a waste material. Each year 40 million tyres are scrapped in the UK. Using tyres in cement kilns help to minimise illegal dumping, reduce landfilling and preserve fossil fuels for future generations.

CEMEX has been using chipped tyres at Rugby works since 2005. Data show a marked reduction in certain emissions from the chimney when tyres are in use. Most notably, oxides of nitrogen which affect air quality, have decreased by 40%.

SLF

Secondary Liquid Fuel (SLF) is made from industrial liquid wastes that can’t be recycled, such as paint thinners, inks and varnishes.

These are blended to a strict specification producing a smell similar to paint and a look similar to engine oil.

Every year the UK generates large volumes of industrial liquid wastes that are non-recyclable and disposed of in specialist landfills or incinerated without energy recovery. By using SLF CEMEX recovers energy from waste that would otherwise be lost to landfill.

The use of SLF does not affect emissions or air quality and has been tried and tested in cement kilns in the UK, Austria, Belgium, France, Greece, Italy, Sweden, Switzerland, Chile and the US.  SLF also helps CEMEX tackle rising energy costs, lowers greenhouse gas emissions and make fossil fuels last longer to benefit future generations.

SLF has been used successfully at CEMEX’s cement plant in South Ferriby since 2002, where it has reduced emissions of sulphur dioxide and oxides of nitrogen by 15% compared to using fossil fuels alone.

The UK Waste Problem

The cement industry has a significant role to play in helping to overcome the UK’s waste crisis, which we all individually help to create.

Landfill is a major issue for local authorities, which face tough targets to reduce what they bury in the ground. By 2010, biodegradable household waste going to landfill must be 75 per cent of the amount produced in 1995. By 2013, this must be reduced to 50 per cent and by 2020 to 35 per cent. Safe disposal of carefully selected and specified wastes in cement kilns is a sensible and sustainable alternative.