Cauldon Works the capacity to manufacture up to one million tonnes of cement each year and is increasing using waste-derived fuels in its drive for increased sustainability in its operations. The works uses a combination of traditional fossil fuels – coal and petroleum coke – with tyre chips and processed sewage pellets. It is also permitted to use recovered fuel oil and has recently been given a permit to evaluate solid recovered fuel, which, it is estimated, could reduce its carbon dioxide emissions by around 17,000 tonnes each year.

The roller shaft, one of six supporting the kiln, was badly worn, so Lafarge decided to replace it at the next plant shutdown. Due to the height and accessibility of the unit under the kiln, Lafarge decided to outsource this work to an experienced contractor, who would be responsible for removing the old roller and installing the complete new roller shaft assembly.

Stephen Haywood, Project Engineer at CNES commented: “We have a very close working relationship with Lafarge and this, coupled with CNES’ vast experience in heavy lifting, removal and installation work, resulted in Lafarge inviting us to tender for the installation work, as well as the manufacturing of the replacement roller shaft. We beat off fierce competition to secure the contract.”

The removal and installation work took five days to complete. First, in order to remove the existing damaged roller shaft, CNES engineers had to jack up one end of the kiln that the roller was supporting. This was carried out using two, 150-tonne hydraulic jacks and the roller removed in a two-day time frame.

This process involved moving it out from its position on skates using lifting slings and lifting beams, connecting to chain hoists and lowering it 8m to a sunken floor. The roller was finally removed from site for scrapping and recycling the steel.

Fitting the new roller was effectively a reversal of the removal procedure. The new roller shaft was manufactured at Corus Process Engineering at Workington. The rotary kiln was then lowered back onto the new roller shaft ready for commissioning by Lafarge’s engineering team. In total, CNES engineers spent around eight days on site changing the rollers over.

Alan Holgate, Estimating Engineer at CNES commented: “For Lafarge at Cauldon, we manufactured the forged steel shaft at Scunthorpe, while the roller forging was delivered to CPE Workington. Engineers at Workington machined the inside diameter of the roller, for Scunthorpe to machine the shaft to just one thousandth of an inch larger than the roller bore. The shaft was shipped to Workington, where the roller was placed in an oven to expand the bore before it was dropped onto the shaft to cool down to a tight fit. Once this had taken place, the main diameter of the roller was machined in a large lathe to the required dimensions and concentricity, before final inspection and despatch to Lafarge.”

www.corusnes.com