Process

sludge2energy Process Variant Hot Water Boiler

The version “Hot Water Boiler” represents a functional system of a simple design for thermal sewage sludge utilisation.
 

sludge2energy process variant Hot Water Boiler

 
Brief description of the technology

  • Sludge acceptance and storage area for dewatered sewage sludge (1) to balance varying supply volumes
  • Full drying of a partial flow in a belt dryer (2) and heat supply through incineration
  • Condensation of dryer vapours, introduction of vapours/air into the fluidised bed furnace (6) as combustion air
  • Intermediate storage bunker (3) for dried sewage sludge
  • Mixing (4) of dewatered and fully dried sludge for auto-thermal incineration
  • Flexible combustion control including adjustable conveying line for combined sludge input
  • Stationary fluidised bed furnace (5) with continuous discharge of bed material and contaminants
  • Burner for plant start-up and shutdown and balancing unsteady operating states
  • Waste heat boiler (6) for heat transmission from flue gas to useable hot water
  • Utilisation of the hot water for heat supply to internal consumers, such as sludge dryer
  • Staged combustion air system to minimize contaminants, such as dioxins, carbon monoxide, organic pollutants and nitric oxides 
  • Denitrification according to the selective non-catalytic reduction (SNCR) method as first stage of flue gas cleaning
  • Fabric filter for pre-separation (7) of the phosphorus-rich flue ash from the flue gas
  • Dry flue gas cleaning (8) with sorbent dosing to remove acid pollutants, dioxins and heavy metals (e.g. Hg)
  • Fabric filter (9) (sorption filter) to remove reaction products and dust from the flue gas
  • Recirculation of the sorption residues to improve separation efficiency and reduce sorbent consumption
  • Measurement station in chimney (12) for the control of all legal emission limits
  • Ash discharge and storage of reaction products (11) separately from phosphorus-rich bed ash, boiler ash and pre-separated ash (10)