CEMEX reduce dust emissions at Rugby plant
One of the biggest operational challenges facing quarry operators is the control of dust and debris that arises from the continuous operation of vehicles and on- site machinery. Failure to limit the effects of unstable and dusty surface areas can lead to operational inefficiencies, while dust emissions that affect local communities and cause contamination of public roadways could result in authority investigation and prosecution.
As part of their wider sustainability commitment, CEMEX UK have recently cut dust emissions at their Rugby cement plant in Warwickshire by 80%, following the successful installation of a state-of-the-art bag filter from Redecam.
Positioned on the plant’s giant exhaust duct, which runs the entire height of the pre-heater tower, the bag filter system represents a £6.5 million investment and has been operational since March this year.
Before installation, two tubular steel duct sections, weighing 17 tonnes each, were fabricated to accommodate the filter system at the plant. As expected, lifting the new sections into place was a major challenge. Hampered by untimely high winds, a mammoth 70m reach mobile crane was used to carefully guide the two sections into place.
With the bag filter system installed, CEMEX have been reaping both environmental and operational benefits ever since. The filter comprises more than 6,000 bags (cleaned regularly by passing compressed air through them), each 6m long and made of highly effective Teflon-coated fiberglass.
The system works by extracting dust from gases produced in the cement kiln. The collected dust, mainly chalk, is then recycled back into the cement-making process, minimizing waste.
In addition to Redecam’s bag filter system, Thermo Scientific have supplied and installed two bypass dust-addition systems at the Rugby plant. Traditionally, CEMEX treated bypass dust as waste, which was normally sent to landfill. However, with the advent of new technology, cement producers can now recover bypass dust, at a controlled rate, back into the manufacturing process with no degradation of the final cement product.
CEMEX had planned to utilize unused storage hoppers with weighing equipment for storing bypass dust and sending it back into the mill but Thermo Scientific determined that normal weighing equipment for this type of application was not suitable, because the system had to be fully enclosed and there would be limitations on the headroom within the mill house.
As specialists in analytical instruments, Thermo Scientific devised a bespoke solution based on two screw conveyor weighing systems for removing the dust from the hopper and feeding it to the mill, at up to 3 tonnes/h.
To achieve this, Thermo Scientific fitted air-operated silo discharge aids, together with associated isolation valves, to ensure bypass dust flowed from the silo in a controlled way. First, the dust flows into the initial screw conveyor – known as the ‘extraction screw’ – and then proceeds into the second ‘weighscrew’, the outlet of which is fed to the inlet of the mill.
The weighscrew runs at three different preset speeds depending on the bypass dust feed rate, while the extraction screw has variable speeds to control the feed rate. To ensure that there are no product blockages in the bypass dust addition systems, Thermo Scientific have fitted their Scientific Microtech
3000 weighing controller and a number of microwave-based flow/no-flow switches.
Ian Lee, project and engineering manager at Thermo Scientific, commented: ‘Although we have a number of these types of installation throughout the world, this is the first of its type in the UK handling a product as difficult to control as bypass dust. This was a challenging exercise, as the screw conveyor weighing systems have to operate under the arduous conditions that exist in a mill area.’
CEMEX’s Rugby Works is one of the most modern cement plants in the world and includes the largest kiln in the UK. The new bag filter and bypass dust addition systems at the plant, together with recent approval for the use of chipped tyres to part-fuel the kiln, exemplifies the company’s commitment to improving and optimizing performance to ensure that quality cement is provided as sustainably as possible.
Redecam Group SpA, Piazza Indro Montanelli, 20 – 20099 Sesto S. Giovanni MI, Italy; tel: +39 0224 3491; website: www.redecam.it
Thermo Scientific, Unit 2A, Swift Park Ind. Est., Old Leicester Road, Rugby, Warks CV21 1DZ; tel: (01788) 820300; fax: (07188) 820301; email: sales.wi.uk@thermo.com; website: www.thermo.com/bulkhandling
As part of their wider sustainability commitment, CEMEX UK have recently cut dust emissions at their Rugby cement plant in Warwickshire by 80%, following the successful installation of a state-of-the-art bag filter from Redecam.
Positioned on the plant’s giant exhaust duct, which runs the entire height of the pre-heater tower, the bag filter system represents a £6.5 million investment and has been operational since March this year.
Before installation, two tubular steel duct sections, weighing 17 tonnes each, were fabricated to accommodate the filter system at the plant. As expected, lifting the new sections into place was a major challenge. Hampered by untimely high winds, a mammoth 70m reach mobile crane was used to carefully guide the two sections into place.
With the bag filter system installed, CEMEX have been reaping both environmental and operational benefits ever since. The filter comprises more than 6,000 bags (cleaned regularly by passing compressed air through them), each 6m long and made of highly effective Teflon-coated fiberglass.
The system works by extracting dust from gases produced in the cement kiln. The collected dust, mainly chalk, is then recycled back into the cement-making process, minimizing waste.
In addition to Redecam’s bag filter system, Thermo Scientific have supplied and installed two bypass dust-addition systems at the Rugby plant. Traditionally, CEMEX treated bypass dust as waste, which was normally sent to landfill. However, with the advent of new technology, cement producers can now recover bypass dust, at a controlled rate, back into the manufacturing process with no degradation of the final cement product.
CEMEX had planned to utilize unused storage hoppers with weighing equipment for storing bypass dust and sending it back into the mill but Thermo Scientific determined that normal weighing equipment for this type of application was not suitable, because the system had to be fully enclosed and there would be limitations on the headroom within the mill house.
As specialists in analytical instruments, Thermo Scientific devised a bespoke solution based on two screw conveyor weighing systems for removing the dust from the hopper and feeding it to the mill, at up to 3 tonnes/h.
To achieve this, Thermo Scientific fitted air-operated silo discharge aids, together with associated isolation valves, to ensure bypass dust flowed from the silo in a controlled way. First, the dust flows into the initial screw conveyor – known as the ‘extraction screw’ – and then proceeds into the second ‘weighscrew’, the outlet of which is fed to the inlet of the mill.
The weighscrew runs at three different preset speeds depending on the bypass dust feed rate, while the extraction screw has variable speeds to control the feed rate. To ensure that there are no product blockages in the bypass dust addition systems, Thermo Scientific have fitted their Scientific Microtech
3000 weighing controller and a number of microwave-based flow/no-flow switches.
Ian Lee, project and engineering manager at Thermo Scientific, commented: ‘Although we have a number of these types of installation throughout the world, this is the first of its type in the UK handling a product as difficult to control as bypass dust. This was a challenging exercise, as the screw conveyor weighing systems have to operate under the arduous conditions that exist in a mill area.’
CEMEX’s Rugby Works is one of the most modern cement plants in the world and includes the largest kiln in the UK. The new bag filter and bypass dust addition systems at the plant, together with recent approval for the use of chipped tyres to part-fuel the kiln, exemplifies the company’s commitment to improving and optimizing performance to ensure that quality cement is provided as sustainably as possible.
Redecam Group SpA, Piazza Indro Montanelli, 20 – 20099 Sesto S. Giovanni MI, Italy; tel: +39 0224 3491; website: www.redecam.it
Thermo Scientific, Unit 2A, Swift Park Ind. Est., Old Leicester Road, Rugby, Warks CV21 1DZ; tel: (01788) 820300; fax: (07188) 820301; email: sales.wi.uk@thermo.com; website: www.thermo.com/bulkhandling
