The future and economics of biosolids in agriculture is becoming uncertain. Whilst incineration is viewed in a negative light, sludge co-combustion is seen throughout Europe as a green alternative. With this in mind, DIRK now provides sludge co-combustion in coal-fired power stations. With co-combustion, DIRK provides a complete solution at a fixed gate price for either dewatered or undewatered sewage sludge. DIRK can offer its expertise based on experiences gained from its state of the art full-scale installation at the EnBW power station in Heilbronn/Germany.
In this plant, energy is recovered from dewatered sewage sludge cake with a dry substance of 25%. The advantages of sludge co-firing at a power station include:
- Low cost
- No drying equipment required (since drying occurs in the coal mills) - simplified operations
- Works with either undigested or digested sludge
- Safe, reliable and proven technology with a low cost solution
- Sludge combustion is only a small part of the capacity of the power station; therefore process is not adversely affected
- Availability of well trained and experienced personnel from power station
- In-built flue gas cleaning facilities
The Heilbronn power station (below) provides 760 MW power and operates at a mid load factor. The plant is equipped with coal dust combustion with dry ash extraction. Tangential burners are directed to the centre of the furnace creating a vortex of fire with a temperature of 1200°C at the middle of the combustion chamber.