WID COMPLIANT WASTE WOOD BIOMASS AND RDF COMBUSTION PLANTS
We have got WID compliant boilers for the C grade waste wood and SRF combustion
Key specifications for our waste wood boilers:
HOW OUR WASTE WID/IED COMPLIANT WOOD GASIFICATION BOILER WORKS?
Two-stage WID/IED compliant waste wood gasification combustion is low in nitrogen emissions. In contrast to conventional grate combustion, glowing ember bed is stationary regardless of power output. And the glowing ember bed is so thick (about 80 cm) that all combustion air oxygen is consumed within the ember bed.
In the absence of oxygen more than 90 % of the nitrogen becomes nitrogen molecules (N2). The remaining nitrogen forms the mainly low oxygenated nitrogen compounds N2O and NO. This is ecologically important, because acid rain causing toxic NO2 compound emissions are very low.
The VTT Technical Research Centre of Finland tested two-stage gasification waste wood combustion boiler (540 kW) and found that when chipboard was burnt nitrogen oxide emissions were at the same level as when clean woodchips were burnt in a grate combustion boiler, in spite of the fact that the nitrogen content of chipboard was more than thirty times higher.
WID/IED compliant waste wood gasification combustion boiler has two stages:
At the first stage primary air enters through the grate to the bottom of the thick glowing ember bed and combustion continues within the ember bed as long as there is enough free oxygen and until all the oxygen has become carbon dioxide (O2+C=CO2) The carbon dioxide then reacts with glowing carbon and forms carbon monoxide (CO2+C=2CO).
As the gas rises from the glowing ember bed, it is mixed with secondary air, causing the gas to ignite. The burning gas enters a narrow chamber where tertiary air is blown into the mixture from all sides, and the gas burns completely within a hot combustion chamber lined with firebricks.
The hot gas rises further into an after burning chamber that prolongs combustion and reduces the amount of unburned gases and dust especially when the fuel used is of low quality and high moisture content.
Because the first stage of combustion takes place within the thick ember bed, which acts like an active carbon filter removing almost all fly ash from the gas, only 2 % of the ash formed rises with the flue gas flow.
The remaining 98 % stays in the ember bed and exits from below to the ash conveyor. This means that the flue gas dust content within the boiler is only circa 50 mg/nm3, keeping the WID/IED compliant waste wood boiler clean and the boiler needs to be cleaned only once a year as part of its annual maintenance.
The flue gas dust content of a conventional grate combustion boiler is more than 1000 mg/nm3. This is why such boilers are equipped with compressed air soot cleaning systems, the disadvantage of which is dust discharges that exceed emission requirements and leave an environmental footprint.
In grate combustion boilers the thickness of the glowing ember bed is initially around 30 cm. The grate moves the ember bed so that the whole bed is burned after travelling along the whole length of the grate. The grate’s movement should always be adjusted to the power output of the boiler and the type of fuel used.
In our WID/IED compliant waste wood gasification boilers combustion is not regulated by moving grates. The thick ember bed remains still and the grate moves simply to cut ash from under the ember bed. The regulation of combustion in our WID compliant waste wood gasification boilers is simpler because only the combustion air needs adjusting.
The regulation happens automatically even if the quality, size or moisture content of the fuel changes. Gasification combustion adjusts to the changes in boiler load much faster than grate combustion.
On top of the thick glowing ember bed there are still more than 2 metres of waste wood fuel in the internal silo. In case of a power cut or other disruption, the boiler runs standby and can restart automatically within another 3 days if the problem is fixed.
In a grate combustion boiler even short-term disruptions may cause the thin ember bed to burn down completely and the boiler requires many hours work to start and reach its required output.
WHY THIS IS IMPORTANT IN UK TO USE WID/IED COMPLIANT GASIFICATION BOILERS FOR C-GRADE WASTE WOOD PROJECTS?
- Gasification technology is the best way to make sure that two second 850 degree requirement is achieved which is required on SWIP
- Our vertical gasification combustion chamber is best to meet more than two second residence time during incineration
- Our technology meets SWIP BAT technology requirements with oil/gas back-up burner
- When more than two second residence time are met, the emissions are lower = Yes we have evidence of that and we can give emission guarantees without bag filters measured 1,5m from the boiler (100%, 75%, 50% and 25% power)
Link to small scale waste incineration legislation where is a clear guidance how combustion residence times must be met :
WASTE COMBUSTION WITH BIOMASS,
Can we get UK Renewable Heat Incentives (RHI) if we use non-biomass based waste fuel together with Biomass?
In WINGAS gasification plant it is possible to burn also SRF (solid recovered fuel) mixed max. 20% with wood that is normally burned in the plant. The SRF fuel that is used must be treated according to EN 15359 standard.
The fuel must be sorted according to sorting instruction.
After sorting the fuel it must be chipped to chip size of <100mm.
You can add the following materials max 20% well mixed with wood that is normally burned in the plant.
Note that all items must be non-hazardous:
- - Plastic bottles
- - Small plastic items
- - Packages that include plastic and paper or cardboard
- - Plastic cords
- - Beverage carriers unless recyclable
- - Plastic household vessels or containers
- - Plastic packages from groceries cleaned (sauer milk, yoghurt, butter or margarine, meat boxes)
- - Styrox, foam
- - All wood waste except classified hazardous wood
- - Clothes and textiles (except PVC, leather and artificial leather)
- - Data discs
- - Cardboard
- - All plastic with plastic material coding 01, 02, 04, 05, 06, 07 (Not PVC)
- - Books with it’s covers
- - Wrapping materials, papers
It is not allowed to include following materials in our WID/IED compliant boilers:
- PVC plastic items (marked with 03). Don’t burn unknown plastic.
- Plastic with marking 07 with O or OTHER under the triangle
- Hazardous wastes
- Food waste = Designed to go to AD plants, or composting facility
- Packaging materials that include aluminium (eg. foils, crisp bags, juice cans, coffee bags)
- Pressurised cans
- Glass, porcelain, ceramics
- Electronics waste
- Toothpaste tubes and toothbrushes
- Leather, rubber, dipers, sanitary napkins
WHICH PLASTICS CAN GO TO COMBUSTION PROCESS IN OUR WID/IED COMPLIANT BOILERS WITH BIOMASS:
- YES: PET - Polyethylene Terephthalate - PET is most often used for cooking oil bottles, soft drink bottles, butter jars.
- YES: HDPE - High Density Polyethylene - HDPE is commonly used for milk jugs, detergent bottles and crates.
- NO: PVC - Polyvinyl Chloride - PVC is used for plastic pipes, water bottles, outdoor furniture, shrink-wrap, liquid containers.
- YES: LDPE - Low Density Polyethylene - LDPE is often used for trash can liners, produce bags, and food storage containers.
- YES: PP - Polypropylene - PP is used for drinking straws and bottle caps.
- YES: PS - Polystyrene - PS is used to make packaging pellets, commonly referred to as 'Styrofoam peanuts'.
- NO: OTHER - Plastics listed in the OTHER category are any not listed in the first six categories.
The production of SRF (Solid Recovered Fuel) may involve some but not all of the following steps:
- Preliminary liberation/sorting
- Course, pre-shredding
- Size screening
- Magnetic separation
- Refining separation
- Fine, secondary shredding
- Baling & wrapping
WASTE WOOD&SRF PROJECTS: HOW TO WORK WITH US
- Please send your WID/IED waste and biomass project details
- We will make an optimal waste wood solution proposal which will meet your requirements and meets WID and SWIP rules
- We will organise waste wood boiler plant delivery to the site
- We will offer onsite support during installation and commissioning during your waste wood project
- Installation is made by our trusted installers and we will offer emission tests to meet WID/IED emission targets
- Handover & training provided for your waste wood boiler plant