Polytechnik

Critical properties of the fuel that significantly influence the operation of a waste wood incineration plant:

• Ash softening temperature (indicator: ratio of Si, P, K to Ca, Mg, Al)
• Impurity content (e.g. metals, non-ferrous metals, sand, stones, etc.)
• Nitrogen, sulphur, chlorine and heavy metal content
• Content of pentachlorophenol (PCP), polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH)
• High-temperature corrosion behaviour (indicator: ratio of sulphur and chlorine content)

• Ash sintering and slag formation (leads to blockages in grate operation and reduced availability)
• Deposits on heat exchange surfaces (reduce heat transfer and boiler efficiency)
• High-temperature corrosion (leading to damage to heating surfaces)
• Corrosion due to condensation of hydrochloric acid, sulphuric acid and sulphurous acid (leading to material damage)
• Emissions of gaseous organic substances and inorganic dust, gas or vapour substances

The plant should be equipped with suitable technical solutions:

• The shape and size of the furnace should be adapted to this type of fuel
• Undergrate RG recirculation (lowers local temperatures and reduces slagging)
• Waste wood-specific grate ash removal (prevents clogging due to ash that is difficult to convey)
• Lower temperature at the furnace outlet – 930 °C (prevents caking and protects downstream units)
• Inlet screen (protects boiler heating surfaces from direct radiation and particle impact)
• SNCR system – selective non-catalytic reduction (targeted NOₓ reduction through urea injection)
• Additive dosing
• Use of a fabric filter instead of an electrostatic precipitator

• In addition to a suitable technical design, stable plant operation also requires an adapted maintenance and operating concept:
• Regular cleaning: at least twice a year – depending on the operating mode and whenever the flue gas temperature at nominal boiler output is 20 K higher
• Maintenance in accordance with the operating and maintenance instructions: for early detection and rectification of faults
• Planned inspections and service runs: to ensure the long-term functionality of the system