New asphalt plant offers energy and space saving advantages for CEMEX

West Lothian based Cormac Ltd have installed and commissioned a complete high efficiency TOP TOWER asphalt plant for CEMEX at their quarry near Shap in Cumbria. Cormac, who are renowned for their high efficiency bitumen storage tanks, took full responsibility for the CEMEX installation, having recently entered into an exclusive UK working relationship with leading Italian asphalt plant manufacturers, Marini SpA.

The new plant has been purchased to produce up to 100,000 tonnes of coated road stone per year, primarily using aggregates from the adjacent Shap Blue Quarry. The coating plant is designed to operate 24 hours per day, seven days per week when required, enabling CEMEX to fulfil night time contracts, carried out to avoid disruption to day time traffic.

Planners placed strict environmental restraints on CEMEX to minimise carbon emissions and prevent dust or debris contaminating the local environment. In parallel, CEMEX needed to minimise plant running costs without affecting performance and product quality. This new generation of energy efficient asphalt plants has been developed to meet customers' demands for versatility, quality and environmentally-friendly solutions. By definition, asphalt production is an energy hungry process. To minimise energy consumption at all stages of the process, the TOP TOWER uses a combination of innovative design and optimised insulation, to bring significant energy savings throughout. Cormac claim that these design concepts can bring energy savings of over 15%, whilst their high efficiency storage tanks provide savings of up to 50%, compared with traditional designs. In parallel these savings also reduce the installed electrical capacity requirements.

The plant design is extremely compact and the main components are brought to site in pre-assembled modular format, thereby reducing on site installation time. The TOP TOWER is technically compatible with all types of asphalt, including hot, half warm and low energy. Depending on the required layout of the storage unit for finished products, it can be configured in either under-mixer or offset format. There is an under-filter storage hopper for recovered fines and also a short fines recycling unit. The patented screen design and direct double access ensures the screen grilles can be changed easily and quickly as required. The multi-function metering-mixing unit features a large section access door, to facilitate the gravity emptying of aggregates, filler and bitumen. This also makes it simple to introduce bagged additives, recycled materials and foam bitumen.

The main burner, which is designed for minimised CO₂ emission and optimised energy consumption, can be adapted to run on light or heavy fuel oil, natural gas and coal. The coating drum features an efficient heat recovery process, recycling waste heat back into the process to further reduce burner fuel consumption.

By its nature, bitumen needs to be transported and stored at elevated temperatures. As a result storage tanks can act as giant radiators if not suitably insulated, gobbling up energy and adding, in their small way, to global warming. Cormac have been successful in significantly reducing the transfer of heat from the inner tank to the outer cladding. This in turn minimizes the amount of energy that is needed to maintain an optimum storage temperature for the bitumen. The new tank design uses a combination of traditional insulation materials combined with a special reflective thermal coating. Together these produce spectacular energy savings compared with a conventionally clad tank design, reducing energy consumption by over 50%. To reduce energy consumption even further, the tanks are fitted with proprietary progressive multistage heating systems, which maintain the temperature of bitumen within a preset bandwidth.

Cormac's MD Steve Corbett is very upbeat about his company's new capabilities and as he concludes: "The Marini designs represent the latest innovations in compact asphalt plant design. With our experience in asphalt plant implementation and bitumen tank design, we can now offer customers cost effective, high efficiency asphalt plants with production capacities from 60 to 300 tph.

Safety and environmental issues are also of paramount importance in our asphalt plant design. Our optimised burners reduce CO₂ emissions, whilst special filters at strategic parts of the plant ensure dust or particles cannot be emitted to the atmosphere. The bitumen storage tanks are fitted with an RBA (Refined Bitumen Association) compliant failsafe safety system to prevent overfilling and spillages. This system allows regular testing of critical components at ground level (GLT) prior to each fill."

Cormac Ltd
Unit 1, Burnhouse Industrial Estate
Whitburn
West Lothian
EH47 0LQ
TEL +44 (0)141 646 2066
FAX +44 (0)141 646 2077