Customer requirements

Nynas Bitumen UK, part of the Swedish AB Nynas Petroleum company, unlike other oil companies, is a bitumen specialist.

They don’t produce products such as petrol and diesel, but just focus their expertise on napthenics and bitumen. At its Ellesmere Port, UK bitumen plant, Nynas manufactures the ‘high-tech’, speciality bitumen so important for the safe and long lasting road surfaces on which we all rely today. Nynas is a leading innovator in bitumen, bitumen emulsions and polymer modified binders and serves the roads and airfields construction sector, and the industrial sector, with modern solutions capable of meeting ever increasing demands.

Nynas’ original bitumen plant had been in operation since 1990 and was due for upgrading. In particular the joints and bends of the pneumatic conveying system used to transport the dry additives were wearing out. Also, the pneumatic conveying system needed a sizeable filtration system which had environmental implications. Nynas concluded that a major plant refurbishment was necessary - not only to double capacity but also to cope with the significant change from straight bitumen products to a wide variety of longer life, more porous, quieter, more malleable, and cold asphalt bitumen emulsions.

Spiroflow solutions

Spiroflow proposed an ingredients handling system comprising 4 Aero-Mechanical Conveyors, 2 Big Bag Dischargers and 2 sack-tip stations plus associated electric controls. The Aero-Mechanical Conveyors range in length from 7 metres to 22 metres and are operating in a variety of attitudes from vertical, inclined, to horizontal and are capable of handling 1.5 tonnes of polymer additives per hour. The 2 Big Bag Dischargers offer high containment unloading and, as there is no net displacement of air, the Aero-Mechanical Conveyors do not require any venting or filtration equipment. As a result, Nynas has seen a substantial improvement in output and received positive feedback about the operation and cleanliness of the system all round.

The bulk ingredients are added by the one tonne bag load via the Big Bag Dischargers, whilst the minor ingredients are added by the sack full - through the sack tip stations. One of the Big Bag Dischargers is mounted on a mezzanine floor above a collection hopper to enable all of the major additive to be charged in one go. This discharger has its big bags loaded by way of a hoist. The other discharger is at ground level and has its big bags loaded by fork lift truck. The electrical control panel for the system was manufactured by Spiroflow and the installation and commissioning were all carried out by our own engineers.

The 50 tonne charge of additives loaded in to each of the mixing vessels is mixed by re-circulation through an external high powered mixer. Once mixed, it is transferred to stirred storage tanks ready for loading into Nynas’ impressive fleet of tankers.

Tony Gresty, the Nynas technologist responsible for the bitumen plant comments, “We are pleased with the operation of the Spiroflow equipment and the fact that the Aeromechanical Conveyor eliminates the Health and Safety issues associated with pneumatic conveying systems”. Asked why Nynas chose Spiroflow to supply the equipment, Gresty explains, “Spiroflow demonstrated that its equipment could handle all our additives. We were also supplied with layout drawings that were instrumental in us choosing this professional company”