Sleaford is not just another sleepy English market town. It is the home of the Sleaford Renewable Energy Plant, providing 65.000 Lincolnshire homes with renewable energy since September 2014. LBP Engineering has assisted Burmeister & Wain Scandinavian Contractor (BWSC) with the optimisation of the processes and future biofueling of the plant.

Mainly straw bales are burnt at the Sleaford plant. In England, straw is stacked in the field. Because of the climate, bales are often still damp when they reach Sleaford. That is bad news for the incineration process, as LBP engineer, Asger Schade explains:

“If the bales stand around for too long, they rot from below. This makes them difficult to transport for incineration because they wither away or get stuck on conveyor belts. It can be a bit of a struggle to manage them. Also, the bales may contain dirt and rocks, and of course they are not easy to burn if they are damp upon arrival at the plant. It makes the entire process more expensive. This applies to everyone, since farmers are only paid for straw that can burn”.

It can be a tricky task to point out a damp bale, particularly so if only part of the bale is wet. LBP Engineering have assisted BWSC through a series of experiments aimed atdetecting moisture in the comprehensive biofuel mass gathered at Sleaford.

“The plant operates four bale lines, across four conveyor belts, leading up to the incinerator. A big crane lifts two times six bales at a time onto the belt. We have affixed three microwave transmitters to the crane to scan all bales and measure the humidity levels at three different points before the bales are placed on the conveyor belt. This gives us better control and allows for a more stable operation of the plant because we are duly warned about the humidity level of each bale. In turn, this allows us to better calculate how to incinerate each bale,” explains LBP project manager Lars Bjarne Pedersen.

In addition to applying microwave transmitters on the crane, LBP Engineering have optimised operations at the Sleaford plant by introducing a measuring procedure already in the barn where bales are stacked upon arrival. This makes it easier to reject useless bales at an early stage.

Each year, the Sleaford plant contributes to the UK green national account by saving roughly 150.000 tons of CO2.