Drying of Woody Biomass - TAPPI · Process Engineering / GEA Barr-Rosin Biomass Boiler Generating extra power from SSD 16 HP Turbine ~ ~ Condenser 0.1 bar LP Turbine SSD Superheater

Process Engineering / GEA Barr-Rosin

BioPro Expo & Marketplace / Atlanta, GA / March 14-16, 2011

Drying of Woody Biomass

Process Engineering / GEA Barr-Rosin

Drying of Woody Biomass

Process Engineering / GEA Barr-Rosin

Conventional Direct Fired Dryer Technology

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Process Engineering / GEA Barr-Rosin

Issues with conventional dryers

• Fire and Explosion Risks• Large footprint• Significant leaks at rotary dryer seals use more energy• Energy input is lost to atmosphere• VOC emissions• Require separate thermal oxidizer for gas clean up

Process Engineering / GEA Barr-Rosin

Superheated Steam Rotary Dryer

5

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Process Engineering / GEA Barr-Rosin

Superheated Steam Dryer

6

Cyclone

Screw

DryingLoops

SuperHeater

PC

GeneratedSteam

TC

Backmix

DRYPRODUCT

WET FEED

Mixer

Air Heater

FreshAir

Process Air

Natural Gas

CombustionFan

Exhaust

CleanLP Steam

ReboilerCold-Hot Wateror Condensatefrom another

process

Condensateto Sewer

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Process Engineering / GEA Barr-Rosin

Progression of heat recovery options

FanAir Heater Dryer

M M E M+E

Tamb Tin Tout

M

FanAir Heater Dryer

M E M+E-R

Tamb Tin ToutR

FanAir Heater DryerM

E M+E

Tin ToutM

E Twb> 200o F Heat Exchanger

Open Cycle dryer

Process Gas RecycleDryer

Superheated SteamDryer

Process Engineering / GEA Barr-Rosin

Water Content / Dew Point Dryer Bleed Off

0. 00

10. 00

20. 00

30. 00

40. 00

50. 00

60. 00

70. 00

80. 00

90. 00

100. 00

0 2 4 6 8 10 12

k g H2O / k g dr y a i r

Dew PointTemperature

P a r t i a l Ga s Re c y c l i ng

SSD Rot a r y Dr um

Ope n C i r c ui t D r y e r

SSD Ri ng Dr y e r

Oxygen/ FuelHeated dryer

Process Engineering / GEA Barr-Rosin

Boiler SSD Dryer Combination

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Process Engineering / GEA Barr-Rosin

Comparisons of burning wet & dry Fuel

Process Engineering / GEA Barr-Rosin

Typical Biomass Properties

11

Process Engineering / GEA Barr-Rosin

-

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

0% 10% 20% 30% 40% 50% 60%

mJ/

kg

Moisture

Heat available in wet Fuel

Heat available

I mJ/kg = 430 btu/lb

Basis for Comparison

Process Engineering / GEA Barr-Rosin13

• Biomass Fuel Poplar• Calorific Value (HHV) 20,750 kJ/kg• Feed Moisture 50 %• Combustion air preheat temperature 130 0C• Flue gas exhaust temperature 90 0C• SSD Product Moisture 5 %• Dryer internal pressure 4 bara• Dryer inlet temperature 440 0C• Dryer outlet temperature 130 0C• Isoentropic efficiency of turbines 88 %

Basis for Comparison

Process Engineering / GEA Barr-Rosin

Biomass Boiler Using Wet Fuel

14

~HP Turbine

Condenser0.1 bar

LP Turbine

Economiser

Wet Fuel40.32 t/hr@ 50% moisture

Economiser

HP Steam70 bar

Boiler100 T/hr

Combustion Air

31 mW

Exhaust900C

Process Engineering / GEA Barr-Rosin

Biomass Boiler with SSD Preheating Feedwater

15

~HP Steam70 bar HP Turbine

Condenser0.1 bar

SSD

Superheater

Bleed Offsteam

Dry Productto Fuel Storage

DirtyCondensate

Economiser

Fuel

Combustion Air

Exhaust900C

31 mWBoiler100 T/hr

Wet Fuel35.2 t/hr@ 50% moisture

400 kW

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Process Engineering / GEA Barr-Rosin

Biomass Boiler Generating extra power from SSD

16

~HP Turbine ~

Condenser0.1 bar

LP Turbine

SSD

Superheater

Bleed Offsteam

DirtyCondensate

EconomiserPre-driedFuel

Economiser

Dry Productto Fuel Storage

HP Steam70 bar

Combustion Air

Exhaust900C

31 mW 2.7 mW

Reboiler

Wet Fuel40.32 t/hr@ 50% moisture

Boiler100 T/hr

400 kW

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Process Engineering / GEA Barr-Rosin

Advantages of using Dry Fuel

• Higher net calorific value & efficiency

• Dry fuel is easier to store & meter which gives better combustion control

• Fuel is stable & will not rot in storage

• Less CO2 emissions

• Low Humidity exhaust & lower acid dew point

• Smaller gas cleaning systems

• Lower exhaust volume

• Less visible plume

• If wet sludges are produced on site dryer gives a consistent fuel

Process Engineering / GEA Barr-Rosin

Flexible Fuel solution can burn multiple fuels

• Any organic waste material• Fibre or Bran• Sawdust• Waste wood• Straw• Lignin• Dried sludges municipal & Industrial• Biogas or waste liquid fuel via auxilliary burner

Process Engineering / GEA Barr-Rosin

Dryer for Softwood waste Northern Sweden

SSD Dryer, Skellefteå Kraft,Northern Sweden

for Wood Chips & Sawdust22 ton evaporation/hour

Product for Wood PelletsRecovered steam to Power &

District heating

Inlet %DS t/h C bar kWFeed 50 50 10 - 395Heating steam latent - (33) 250 25 17540Electrical power - - - - 1000Total 50 18935OutletProduct 90 22.8 100 1235Generated steam - 27 145 4.2 17500Heat losses 0.2 100 - 200Total 50 18935

Process Engineering / GEA Barr-Rosin

Dryer for Wood Waste Denmark

SSD Dryer, for Energi E2Located at Jünkers flooring plantin Köge, Denmark for wood pellet production shipped to Avedore Power Plant20 tons/hr evaporation Recovered steam to drying & curing ovens for flooring

Process Engineering / GEA Barr-Rosin

Dryer for Sawdust

Super-heated Steam Dryer, Techwood BV, Netherlands

Sawdust for compositeprofiles, 2 ton/h

From 85% up to >99% dryness