From fumbling in the dark to optimising the unseenVast amounts of dust and spillage have reduced the capacity at Avedøreværket, home to a large fuel transport plant near Copenhagen. An in-depth optimisation of the plant's bioconversion processes is urgently needed – but how do you diagnose design flaws when you can only see the symptoms and not the underlying causes?
With a current capacity of 450 tons of wood pellets per hour, the fuel transport plant at Avedøreværket only delivers 75 percent of its ideal capacity of 600 tons per hour for a planned bioconversion project and an existing wood pellet combustion unit. The client, DONG Energy, has asked Ramboll to take an in-depth look at the conveyor belt processes at the plant to uncover any optimisations that can be achieved.
Delving into the unknown
Plant deficiencies are extremely difficult to identify because most components are visually shielded from the human eye. Dust build-up and spillage accumulation are merely symptoms of design problems in or between the plant components.
One frequently used option is to build a new plant from scratch, but this does not necessarily solve the underlying issue. Plant capacity can only be optimised by better design – and a new plant may not fare any better than the old one. The technical system is so complex that it calls for an alternative approach for identifying optimisation areas as opposed to "trial and error" or engineer's intuition.
DONG Energy found that they could save up to 85 percent by redesigning their existing plant rather than building a new one. When optimised, the conveyor belt will not accumulate as much dust and spillage. It will thus regain most of its lost capacity.
|- The technology itself is fairly straightforward. The real issue is that there might be symptoms in the form of dust build-up and capacity deficiencies throughout the plant, but the causes usually exist in the transitions between the different components of the conveyor belt. If the belt has not been ideally designed, we see massive spillage. Hence, we need to take a holistic look at the interplay between the components to identify design optimisations, says Filip Reinhold Nielsen, Engineer for Boiler, Combustion and Fuel Logistics at Ramboll.|
3D visualisation is the key
On a daily basis, the power plant uses millions of small wood pellets that pass through a complex chain of processes to be converted into power. To pinpoint where design optimisations can be made, Ramboll ran an array of 3D visualisations and simulations of the plant's conveyor belt processes.
- Our 3D visualisations and simulations showed that there was room for improvement in certain processes. In many of our simulations, it was clear that the existing design does not properly protect the wood pellets. This causes massive dust generation and accumulation over time and reduces the plant output. Through a design strategy using 3D visualisation and simulation we were able to demonstrate to DONG Energy that redesigning these components will increase plant capacity significantly, Filip Reinhold Nielsen explains.
Insight into physical facilities required
To conjure up an accurate picture of the processes at a plant, it is vital that the engineering team has access to the physical facilities. This enables them to perform a variety of physical tests on plant components. The tests and the resulting simulations will still contain uncertainties, but they will still yield more comprehensive and accurate results than by merely looking at design drawings and theoretical output.
- Simulations are only as good as the data you base them on. However, the advantage is that we can test potential design changes and their effects quite accurately. These effects can be compared to the existing design, so we know how plant operations can be optimised, Filip Reinhold Nielsen adds.
Massive savings potential for plants
The new design optimisation concept developed by Ramboll can be applied to numerous other types of energy-generating plants as well.
- The savings potential is massive for plants experiencing poor performance. Using 3D modelling and simulation, it is possible to identify design flaws, which may lead to excessive dust emissions and spillage throughout the process chain. A malfunctioning plant might not need to be replaced, but simply upgraded. This can save millions while ensuring optimal output, Filip Reinhold Nielsen concludes.
Read more about our bio-conversion services.
Filip Reinhold Nielsen
Engineer, Boiler, Combustion and Fuel Logistics
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