Ferrybridge Power Station
Keen to increase the proportion of biomass used in its boilers at Ferrybridge Power Station, thereby reducing coal usage and minimising the environmental impact of its boilers, Scottish and Southern Energy needed to introduce state-of-the-art burners, as well as the latest automated handling system to store and convey this potentially explosive material. Swedish specialists TPS Termiska were brought in to introduce this new technology and deliver a complete biomass handling solution.
TPS turned to the UK's leading bulk storage and handling systems specialist, Portasilo Bulk Handling Systems, to complete the materials handling elements of the package.Working closely with TPS and Scottish and Southern Energy, Portasilo developed a tailored system for the specific challenges of the Ferrybridge site, incorporating high-performance components from across its product range.
The biomass wood pellets are delivered into tipping booths, from where six Portasilo Augerflo variable-speed feeders transfer the product into a pipe conveyor.This fully enclosed conveyor protects the volatile pellets from moisture and is ideal for transporting material over long distances. After travelling for half a kilometre in this pipe, the pellets are deposited into a 5,000m3 intermediate storage silo.
Because of the material's potentially explosive nature, Portasilo fitted more than 120m2 of explosion relief vents to the silo roof. These modifications ensure the silo meets the requirements of ATEX legislation. This silo is fitted with an advanced hydraulically riven rotating screw extractor, which sweeps the 14-metre base to collect material from the full silo cross-section. From the silo pit a chain conveyor, ideal for explosive materials, feeds the pellets into another pipe conveyor, which transports the material to the boiler house.
Here,two Portasilo 900mm diameter screw conveyors feed the pellets into two five-metre diameter day-silos.Screw conveyors are used to achieve a controlled transfer of accurate volumes of material into the silos.The day-silos were constructed at the purpose-built Portasilo facility,which is capable of fabricating very large silos in one piece,significantly reducing site costs and build time.
The installation of these silos demanded a precision operation, since they had to be lowered into a steel framework by crane with only inches of clearance on all sides.This operation was carefully planned by Portasilo to minimise disruption to the plant.
From the day-silos, biomass is transferred into six disc mills that feed the new burners.To enable the feed rate from the day-silos to be independently variable, Portasilo Osciflo bin dischargers were used, giving a variable discharge rate of between 0.4 and four tonnes per hour into the mills.
The complete solution from Portasilo included all platforms and supporting steelwork, as well as full-length gantries along the pipe conveyors to provide full maintenance access.
Comments from the Client:
Andrew Mills, Project Manager at Ferrybridge Power Station
"The installation and commissioning of the Portasilo equipment was completed with no disruption to the normal operation of the plant.The advanced system devised by Portasilo fulfils our requirements and is currently delivering increased volumes of biomass into our new burners."