Post on 06-Jul-2020
transcript
Environment and Process Technologies / S. Solmaz
European Workshop
Thermal Treatment of Sewage
Sludge for CHP ApplicationsBrussels, 15. – 16. September 2003
Environment and Process Technologies / S. Solmaz
Percentage of Sludge Volumes by Disposal Channels in EC, 2002 and 2009
6%
20%
21%
7%
23%
18%
46%
7%
45%
7%
OtherCompostingThermalLandfillAgriculture
Key:
Inner Circle = Year 2002
Outer Circle = Year 2009
Environment and Process Technologies / S. Solmaz
Price Trends by Services in EC, 2002
0 18 36 54 72 90 108
Price Range (EURO per wet ton)
Transport
Landfill
Agricultural Recycling
Composting
Thermal
Serv
ice
= Average Price
€
Environment and Process Technologies / S. Solmaz
Water Content
Weight-Loss of 1 ton Sewage Sludge throughout typical Sludge Treatment Route
-50
50
150
250
350
450
550
650
750
850
950
0,00% 10,00% 20,00% 30,00% 40,00% 50,00% 60,00% 70,00% 80,00% 90,00%D.S. [%]
Wat
er M
ass
[kg]
0
100
200
300
400
500
600
700
800
900
1000
Water
Dry Substance
Thermal Drying(cell and chemically bonded water)
Dewatering(bonded and capillary water)
Thickening(water free)
Tota
lMas
s[k
g]
Environment and Process Technologies / S. Solmaz
Bio Solids Use and DisposalWaste to energy by incineration of sludge cake at 20 – 40 DS with power production
Incineration and energy recovery of sewage sludge at an average DS content of 25% results in a power production of 250 – 300 kW/TDS. The incineration plant itself has a typical parasitic power load of 250 – 300 kW/TDS. The final product from the plant is an ash that can be used as a raw material for manufacture of civil engineering products.
Waste to energy by incineration of dried sludge at 90 % DS
Energy recovery from a plant processing dried sewage sludge at 95% DS results in a power production of 700 –1000 kW/TDS. The plant itself has a typical parasitic power load of 300 – 330 kW/TDS. The final product from the plant is an ash that can be used as a raw material for manufacture of civil engineering products.
The agricultural use of the dried sewage sludge as fertilizer and for the soil improvement
Total Dry Substance on oats / container
Fertilizing without
sewage sludge 17.6with sewage sludge 1000 kg N / ha 37.6with sewage sludge 2000 kg N / ha 45.9with sewage sludge 4000 kg N / ha 49.6with sewage sludge 8000 kg N / ha 48.9with artificial fertilizer1000 kg N / ha 42.9
• Sewage sludge has a positive effect on plants and enables high yield• Even overdosed the fertilizing effects remain due to high buffer capacity of sludge• The organic compound of the sludge increase the humus content of the soil.
Conclusion:Sewage sludge is a high efficiency Nitrogen fertilizer with additional ability to improve the soil due to the organic matters contained in the sludge. It also serves as a fuel resource for energy production. In both cases drying is the most beneficial way for its preparation.
Environment and Process Technologies / S. Solmaz
Thermal Drying of Sewage Sludge
Convective Drying Contact Drying
water vapour
water vapour
flue gas orhot air
gas andwater vapour
flue gas orhot air
gas andwater vapour
heating medium
water vapour
air
Heat is transported via a lateral surface to the sludge. The humidity evaporates and is discharged.
The sludge is directly dried by the flue gas or hot air and the humidity is discharged.
Environment and Process Technologies / S. Solmaz
Drum Drying System - Direct heated system
dewateredsludge
fuel
mixer
crusher
separatordrum dryerburner
condenser
offgastreatment
(e.g. biofilter)
screen
driedmaterial
Environment and Process Technologies / S. Solmaz
Daldowie (Glasgow)
• Plant Type: 12 Centrifuges D7LL, 6 Drum Drying Lines DDS 40
• Input: Industrial and municipal sludge
• Dewatering: from 2 to 28 % TS
• Drying: from 28 to 92 % TS
• Final Product: 1 – 6 mm granulate
• Evaporation rate: 22.000 l H2O / h
• Start up: 2002
Environment and Process Technologies / S. Solmaz
Louisville and Jefferson country (USA)
• Equipment Type: 4 x DDS 90
• Inlet: Biosolids, at 22% TS
• Product: 92 % TS; 1 – 4 mm Granulate
• Evaporation: 36.000 kg H2O / hr
• Start up: 2002
Environment and Process Technologies / S. Solmaz
Drum Drying System – Indirect heated system
offgas
heatexchanger
dewateredsludge
fuelcombustion air
mixer
crusher
screen
dried material
separator heat recovery( option )
condenser
dryer
furnace
Environment and Process Technologies / S. Solmaz
DDS – Bran Sands Simplified Process Flow DiagramRegional Sludge Treatment Centre(R.S.T.C.)Bran Sands / GB
dewateredsludge mixer
crusher
screen
driedmaterial
condenserfilterdrum dryer
pelletpress
polyelectrolytes
strainingsto compactor unit
elevator productsilocooler
strain press
belt press
furnace withburner
natural gas orkerosene
sludge fromstorage
chimney
mixingtank
to effluentsump
heatexchanger
diverterdamper
hot gas fromgas turbine
to bypasschimney
bypass of pellet mill
sludge pump
condensate pump
condensate toeffluent sump
regenerativethermal oxidiser
offgas treatment
burner
or kerosene
chimney
air
air
heat exchangerhigh qualityprocess water
coolingwater
natural gas
Environment and Process Technologies / S. Solmaz
Bran Sands
The peripheral equipment comprises:
• 3 parallel gas turbines (fired by natural gas, 5 MW each), supplying hot exhaust air (approx.430 °C) as heating energy to the dryers and, more importantly, producing electric current supplied to the national grid.
• a complete sewage treatment plant for the filtrates produced in the sludge dewatering stage, for treatment up to receiving water grade.
Environment and Process Technologies / S. Solmaz
Fluidised Bed Sludge Drying Plant
A
B
CA,B,C
Cyclone
Mixer
Fluidized bed drier
ScreenCooler
Sludge to product storage
Thermooilcircuit Main fan
Aspiration filter
Condenser
Dewatered Sludge
Crusher
Environment and Process Technologies / S. Solmaz
Palm 1
• Plant Type: CDS 60 fluidized bed dryer
• Feed: bio and DAF sludge,Dewatered to 35 % DS
• Product: 95 % DS;1 – 4 mm Granulate
• Evaporation: 6.000 l/h H2O - design
• Start up: 1999
Environment and Process Technologies / S. Solmaz
Palm 2
• Plant Type: CDS 20 fluidized bed dryer
• Feed: bio sludge,Dewatered to 16 % DS
• Product: 95 % DS;1 – 4 mm Granulate
• Evaporation: 2.000 l/h H2O - design
• Start up: 2002
Environment and Process Technologies / S. Solmaz
Belt Drying System
B iofilter
C ombustionchamber Option 1 : Belt Dryer direct fired and air recycling loop
Dr iedP r oduct
E xhaust gas D ry er
Cond
ense
r
C oolingair
P r oductfeed
C ombustionchamber
E xhaustcombustion air
H eat exchanger Waste heatr ecov er y
e.g.S team
E xhaust gasesH ot w ater
Option 3: Belt Dryer with closed loop and indirect heated with waste heat
Option 2 : Belt Dryer with closed loop andindirect heating with burner
H eat exchanger
Environment and Process Technologies / S. Solmaz
Altenrhein (Germany)
• Equipment Type: Belt dryer (BDS)
• Inlet: Biosolids,Inlet Consistency at 28-30 % TS
• Product: 92 % TS;Granulate
• Evaporation: 400 kg/hr H2O
• Start up: 2002
Environment and Process Technologies / S. Solmaz
Comparison of the different dryer types
DDS CDS BDS
Granulate Dimensionally stable, round granules of 2 to 4 mm; Virtually dust free
Dimensionally stable, round granules of 2 to 4 mm Virtually dust free
Dimensionally stable, round granules of 1 to 8 mm
Energy sources for drying
Natural gasBio-GasExhaust gases from gas turbineExhaust gases from gas engineWood-gasification process gasThermal Oil
Steam @ 10 bar saturatedThermal oilExhaust gases from coal fired power plants
Natural gasBio-GasSteam @ 4 bar saturatedThermal OilHot waterExhaust gases from processes at low temperature (~ 140°C)
Environment and Process Technologies / S. Solmaz
Combination of dryers with CHP processes Block Flow Diagram
DEWATERING
DRYING DDS
COOLING
HEAT GENERATION
GAS ENGINE
RTO
STORAGE PRODUCT
GAS SUPPLY
FINAL EFFLUENT SUPPLY
FINAL EFFLUENT RETURN
EXHAUST AIR
STACKNEW BATCH
TANK
RAW SLUDGE
DEWATERING
DRYING DDS
COOLING
HEAT GENERATION
GAS ENGINE
RTO
STORAGE PRODUCT
GAS SUPPLY
FINAL EFFLUENT SUPPLY
FINAL EFFLUENT RETURN
EXHAUST AIR
STACKNEW BATCH
TANK
RAW SLUDGE
Environment and Process Technologies / S. Solmaz
Eco-Dry Principle Block Diagram
Flue gasrecirculation
Secondarycombustion
Offgastreatment
Ash Storage
Heat exchangerDryer
Crusher Incinerator
Granulat
Cooling water
Combustion air
Cooling Water
DewateredSludge
Exhaust air
Final product
Environment and Process Technologies / S. Solmaz
Cyclone furnace
ash
start up burner
exhaust duct
primary chamber
Ground granulate and conveying Air
hot gas
ash
Combustion Air Supply
Cooling Air Supply
Hot Cooling Air
Combustion Air Supply
secondary chamber
Environment and Process Technologies / S. Solmaz
Drying and Incineration with combined Heat and Power
Stack
ECO-DRY
ECO-DRYSteamBoiler
SteamBoiler
Flue gascleaning
CDS dryer
CDS dryer
SteamTurbine
GBoiler drum
Gas for Start-uponly
GranulateDS: 92%1.587 kg/hr6.245 kW
Wet sludge: 5.615 kg/hr, DS:26%Heat input: 2.941 kW
Wet sludge: 5.615 kg/hr, DS:26%Heat input: 2.941 kW
GranulateDS: 92%1.587 kg/hr6.245 kW
Power Generation
Granulate3.174 kg/hr
Flue gas33.602 Nm³/hr180°C; 4.769 kW
Steam: 12.575 kg/hr400°C; 40 bar;11.178 kW
1,565 MW elec.
Flue gas:16.800 Nm³, 850°C7.204 kW
Flue gas:16.800 Nm³, 850°C7.204 kW Steam: 10.580 kg/hr
180°C; 10 bar;9.697 kW
Environment and Process Technologies / S. Solmaz
CO2 Balance
71.160 t CO2/a
Erdgas:
2.128.000 Nm3/a
Erdgas:
0 Nm3/a
-61.032 t CO2/a
(+ 3.796 t CO2/a)
(+ 6.332 t CO2/a renewable)
-64.828 t CO2/a
(+ 6.332 t CO2/a renewable)
CO2-Reduction: 91%
CO2-Reduction: 85%
Dewatering
Drying
Incineration
Disposal
Savings Natural Gas2.128.000 Nm³/a
71.160 t CO2/a
Erdgas:
2.128.000 Nm3/a
Erdgas:
0 Nm3/a
-61.032 t CO2/a
(+ 3.796 t CO2/a)
(+ 6.332 t CO2/a renewable)
-64.828 t CO2/a
(+ 6.332 t CO2/a renewable)
CO2-Reduction: 91%
CO2-Reduction: 85%
Dewatering
Drying
Incineration
Disposal
Savings Natural Gas2.128.000 Nm³/a