Tarmac cuts carbon by 40%

Carbon emissions from 868 Tarmac UK’s Tunstead cement plant are set to be cut by 40% following investment in a new lime kiln at the site in Derbyshire.

The new £13.4million (€16.2million) 1853 Maerz kiln replaces two existing rotary kilns that were installed in 1955. Tarmac has already cut energy consumption at the site by 35% in the last five years through investment in efficient plant and by introducing waste-derived fuels but the new kiln will further cut costs and reduce emissions.

According to Tarmac, the Maerz kiln is the most efficient lime kiln currently available. By pre-heating the feed limestone, much of the heat is recovered; ensuring less energy per tonne of lime is required in production. The new kiln will reduce carbon emissions per tonne of quicklime by 40% and cut sulphur dioxide by over 90%.

Managing greenhouse gas emissions and reducing energy use are key sustainability commitments for Tarmac. This new kiln will help to better manage the environmental impact of our operations and reduce energy consumption,” said Tarmac head of sustainability Dr Martyn Kenny, Head of Sustainability. “Investing in new, more efficient technology is vital to delivering the sustainability targets that are central to our business strategy, and also helps to ensure that we run our operations as costs effectively as possible.”

Fuelled by natural gas, the Maerz kiln processes 40-20mm limestone to produce high-purity quicklime (calcium oxide), a product commonly used in industrial effluent treatment, concrete building blocks, steel making and soil stabilisation.

It took nearly two years to complete the design and construction of the new kiln, which consists of two inter-connected, vertical shafts connected to each other by a cross-over channel, which are fired in sequence to achieve excellent energy efficiency.