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Our technology

Combustion Systems

Over the course of more than 100 years, VYNCKE has acquired a lot of expertise in converting biomass and other solids to energy. With more than 4000 references worldwide, VYNCKE installations provide energy from hot water heaters, steam boilers, thermal oil heaters, multimedia plants (hot gas, thermal oil, steam, power generation in one system) and combined heat and power plants.

VYNCKE designs and builds the entire energy plant from fuel storage to chimney, including the combustion and boiler technology, flue gas cleaning, power generation, and control and automation of the total plant.

The combustion system is the heart of the energy plant. Already since the mid 80’s VYNCKE has been using its DWS, Dynamic Water-cooled Stepgrate. This stepgrate was designed and developed specifically for combustion of dry solid fuels with high calorific value. This technology also proved very suitable for dealing with poor quality fuels that have high slagging and sintering properties.


The DWS has now evolved into a multi-fuel grate firing system. It comes in many models, like the DWS-FW (fully water-cooled) grate which is designed for dry fuels or fuels with low ash fusion temperatures; the DWS-SW (semi-water-cooled) grate that deals with the fuels with very high moisture content; or the DWS-Hybrid grate that combines the best of the SW and FW type of grate and that is now the most fuel-flexible combustion system in the world.

With more than 900 units sold worldwide VYNCKE has the most references at industries that use this type of water-cooled stepgrate. This includes installations that span multiple fuels and a variety of energy media.

Most of the solid fuels are fired on our DWS stepgrate but fine solid biomass material can also be burned in suspension.

Principle of water-cooling

Just like with combustion engines in cars, we use water to remove the heat from our combustion system. Water is inexpensive and the advantages of using water cooling over air cooling are: water’s higher specific heat capacity and better thermal conductivity. This allows water to transmit heat with a reduced temperature difference. The fuel feeding door, the surface of the step grate, the furnace walls and the deashing conveying system are all mechanical parts that are exposed to a temperature of 1000°C. Being water-cooled, together they form a water jacket around the combustion system to ensure long life of the energy plant.

The energy absorbed by the water-cooled step grate is always retrieved. It is either injected in the main steam/hot water cycle or dissipated through preheating of combustion air. As such the principle of water-cooling does not reduce the overall plant efficiency.


Adapting technology to the fuel

Most of the solid fuels are fired on our DWS stepgrate but fine solid biomass material can also be burned in suspension.

We always try to burn the available fuels as they are, and have the possibility to combine our grate systems with a wide range of suspension burners, going from standard injection nozzles to multi-fuel burners where also fossil fuels or other process waste flows can be burnt. Our different types of fuel feeding systems, which bring the fuel into the combustion room, are always designed to match the specific properties of the fuel.






Here is a short teaser video of what goes on in the back-end when your DWS step grate is being made. This is from our manufacturing unit in Czech Republic. 

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