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Artur ŚwiderskiP.O. Box 557

SE-611 10 NYKÖPING, SWEDENPhone +46 730 28 49 12

Fax +46 155 67 91 39www.wtsab.com

The 100% conversion of steam boiler at CHP plant and rotary kiln furnacesat asphalt plant to firing biomass fuel

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Presentation structure

� Introduction company profile,

� Conversion of 120t/h steam boiler (CHP) coal fired to a biomass fired,

� Conversion of light oil fired burners installation to bo-oil.

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World Thermal Service AB company profile

� Production: WTS has own product it is biomass powder burner. The burners are designed for two or three fuels: biomass powder, gas (natural or process), oil (light, heavy or process)

� Design: Biomass storage, pneumatic transport, milling and dosing units for combustion systems. Oil and gas trains for burner.

� Consulting: biomass installations, pellet production, evaluation of existing installation as third part, feasibility studies.

05

1015202530354045

6 10 16 20 25 30 35 40

Burner capacity [MW]B

urne

r op

erat

ion

rang

e [M

W]

WTS burner operation range

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Burners location on boilers and boilers types

Water tube boiler, top fired

Water tube boiler CHP,tangential fired

Horizontal furnace, tubular boilers

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Burners location on boilers and boilers types

Vertical top fired furnace hot gas generators for biomass dryers

Burner located over coal grate

Co-firing biomass with coal powder burners at CHP power plant

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Advantage of wood powder firing system

� Fast start time from cold condition mostly limited by purging (ventilation) time of boiler/furnace,

� Full automatic ignition sequence, start from distance. All sequences are automatic implement in control system,

� Burner can increase load from minimum to maximum in 50s. Operation similar to gas or oil burners. Normally process heating curve limit this time,

� Short stop time. There is not stored heat in powder burner that can cause damage of down stream system (boiler, dryer) if quick stop is needed,

� Burner light on fossil fuel and then it is automatically switched to biomass fuel. The fuel switch can be done at low load. There are no required minimum process parameters (furnace temperature) for making a fuel switch,

� Biomass is fired without any support fuel,� Turn down ratio on biomass fuel is 1:5,� System can be adapt to different client requirements:

– Burner can firing two fuels in same time. Mix mode,– Burner can firing wood powder to limited level and pick energy requirements can be covered

by second fuel. Booster mode,– Driftnet fuel combinations biomass powder/gas, biomass powder/oil, biomass

powder/gas/oil,– Direct ignition on biomass fuel at defined process conditions, furnace temperature,

� WTS has a special designed powder combustion system that can be used for difficultfuels with high fuel N and low ash fouling and melting temperatures,

� Low amount of un-burn in ash compared to other technical solutions.

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100% conversion of a 120 t/h steam boiler coal fired at CHP to biomass fuel

Project in numbers:� 8 Burners fuel: natural gas / biomass powder, maximum capacity 16,5MW per burner. Total thermal load 100MW at 6 burners in operation,�Raw biomass silo, 4 hammer mills, powder silo, transport line from milling house to boiler house, dosing systems to burner, natural gas installation,�Steam production for turbine: 120t/h with temperature 500oC at pressure 7,5MPa.�Flue gas emission: NOx and CO bellow contract limits (NOx 400 mg/nm3),�Biomass fuel: a wide range of combust biomass source, wood and mixture of wood biomass with agro biomass,�System is design for pellets and micro chips biomass with wide range of density,�Total weight of delivered machinery: 236 ton,�Total project cost 39 000 000EUR.

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Scope of WTS work

4 mills house

Raw biomass

silo

V=300m3

Powder silo

V=200m3

Pneumatic transport

Mills house → Boiler house

Boiler house:

Biomass dosing system with 8 burners and natural gas trains

Powder preparation

Out of WTS AB scope:

Pellet receiving station

Chips

dryer

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Biomass as chips or/and pellet

Biomass shape:� Chips (hog fuel) supplied from dryer by

pneumatic transport,� Pellets supplied to receiving station,Biomass source:� Forest biomass,� Agro biomass.

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Biomass handling systemView of milling house with: 1/ Raw biomass silo 300m3 with out-feed system,2/ Building with four hammers mills. Nominal capacity 21t/h of powder. Powder 100% bellow 1mm and 70% bellow 0,5mm,3/ Pneumatic transport with 4 powder separation units,4/ Powder silo 200m3 with out-feed system,

5/ Two pneumatic transport systems 2xDN250, length 140m, altitude 15m, capacity 2x15t/h.

All transport systems can handle material with bulk density from 120 to 650kg/h,Biomass LHV as receive in range 16,5-18,0MJ/kg, average of all use fuels,Biomass moisture content 6-10%,Up to 45% of agro and 55% forest biomass,Ash content up to 5%,Nitrogen content 0,6%,

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Powder receiving and dosing systems and burners

� Two biomass powder receiving stations,� Two powder dosing systems for 8 burners,� Gas pressure reduction stations,� 8 gas trains one for each burner,

� Burners: turn down ratio 1:5, combustion air temperature up to 330oC burner load 3,3-16,5MW can be reach on biomass and natural gas fuel,

� Control system for burners,

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Biomass properties, density

Top layers of material compress bottom of deposit (chips or powder)

Powder properties:

1/ Wood powder

2/ 100% bellow 1mm, 70% below 0,5mm

3/ Moisture 10%

4/ Test were performer by increasing weight on material surface

Wood powder density change

1,00

1,10

1,20

1,30

1,40

1,50

1,60

1,70

0 20 40 60 80 100

Relative pressure [%]Relative material high [%]

Rel

ativ

e de

nsity

[-]

"Top of silo" "Bottom of silo"

A. Swiderski

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Biomass properties, density

Conclusion:

� In dosing bins should be all time constant level of material for keeping equal mass flow of product,

� Low density materials can cause problems for detection by some types of level sensors,

� Transport systems (screws feeder, chain conveyers) are volumetric machines. If input material density fluctuate it should be identify and assume at design project stage.

14

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Bio

ma

ss p

rop

ert

ies,

de

nsi

ty

Densi

ty d

epends

on m

ate

rial ty

pe a

nd s

hape.

010

020

030

040

050

060

070

080

0

Coars

e saw

dust

Larg

e size

woo

d ch

ips

Fine w

ood c

hips

(nee

dle) W

ood p

owde

r (W

TS)

Sun fl

ower

hull

s pow

der (

WTS

)

Soya

hulls

pow

der (

WTS)

Chips a

nd su

n flo

wer p

ellet

mix

Whi

te pe

llet fi

8mm

Sun flo

wer hu

lls pe

llet fi

8mm

Black

pelle

t fi 6

mmDensity [kg/m

3]

A.

Sw

ider

ski

Input

mate

rial

Co

mp

ress

ible

m

ate

ria

l

Input

mate

rial

Outp

ut

mate

rial

No

n

com

pre

ssib

le

ma

teri

al

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Biomass type and structurePowder, 60% agro 40% forest biomass

Chips, 100% agro

Powder, 100% white wood (pellets)

~60% Chips 40% pelletsfi6mm (wood+agro)Pellets 60% wood fi12mm,

40% agro fi6mm

� Pellet from white wood, sun flower hulls. The diameter 6-8mm, length 3-4xd

� Chips from willow, wood residues with bark. Size 5x5x5mm

� Shredded straw

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Biomass properties, powder particle structure

Coal powderCoal powder 500x Wood powder 25xWood powder 25xWood powder 25x Straw powder 25xStraw powder 25x

Soya hulls powder 25x Wood powder 25x, roll mill

Wood powder 25x, roll mill

Willow powder 25xWillow powder 25x

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Biomass properties, physical structure

Conclusion:

� Compressible material is not self-flowing material. Transport machinery, chutes and silos have to be designed to avoid bridging and plugging,

� The transport screws for compressible material have to be designed to avoid plugging.

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Biomass properties, moisture content

Moisture content in fibers cells has impact on energy demand formilling to powder

Conifer wood structure (pine) Leafy wood structure (oak)

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Biomass milling properties

20

70

120

170

220

270

320

370

0 5 10 15 20 25Moisture content [%]

Mill

ing

pow

er [%

/t]

Screen fi1,6mmScreen fi2,4mmScreen fi3,2mm

Conclusion:Higher moisture content in the wood willincrease the energy consumption for finemilling.Decreasing powder size by reduction of screenholes size increases the energy consumptionfor milling,Higher moisture in material increase risk of bridging.

Hammer mill. Material is cut by moving hammers located on four shafts on the rotor.The hammers moves the material and it is cut on the screens

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Biomass properties, ash content

Conclusion:

� Ash content depend on biomass type,

� Biomass source, subspecies,

� Supplier regime of production and transport.

-

1

2

3

4

5

6

7

8

9

0 5 10 15 20 25Days [dd]

Ash

con

tent

[%

]

Wood pellet Sunflower pellet

Chips Straw rols

Wood pellet

Sunflower husk pellet

Chips Straw rols

MAX 1,5 4,25 4,05 9,5MIN 0,07 1,0 1,3 3,1

MAX 6,90 3,80 4,30 7,80 MIN 1,00 2,60 0,40 3,10

From month tests

From literature

Monthly ash content measurement

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Biomass properties, ash content

High ash content increase polishing effect on surface in rotating machines and in pneumatic system bends, pipes

Contamination in fuel like stones, sand cause fast damages of moving parts (hammers). Impacts marks on machinery surface. Damage hard cutting surfaces.

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Biomass properties, nitrogen

05

1015202530354045

0 1 2 3 4Fuel nitrogen [%]

Tot

al c

onve

rsio

n ra

te [

%]

NOx in flue gas [mg/Nm3]

BiomassFuel nitrogen

[%]Sunflower husk pellet 0,9Sunflower husk pellet 3,27Sunflower husk pellet 1,81

Wood pellet 0,42Wood pellet 0,18Straw rols 1,01

Conclusion:

� Investment cost in nitrogen oxide reduction system can be reduce by selection fuel with low nitrogen content.

Fuel nitrogen conversion to nitrogen oxide (NOx) tendency

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Biomass properties, explosion

Biomass parameters:� Index of maximum rate of pressure rise Kst [m·bar/s]. For wide range of biomass is in range

Kst=9-161m·bar/s. Maximum explosion pressure for biomass is in range Pmax=5,9-8,4bar� The biomass type should be identify and assume at design project stage. Wider range of

biomass type increase costs of protection systems.Preventing systems:

– Spark and glowing particles detectors, – Electronic nose, multi gas component detectors in silos,– Multi point temperature detectors in silos

Glowing particles detectors and water injection nozzles at silo inletTemperature sensors in silos

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Systems

� Protection systems– Passive - explosion

panels, Q-box– Active - suspension

systems

No equal explosion panels location on silo wall

Top explosion panel location on filter and cyclone

Q-box, explosion panel with flame quenching cover

Suspension system installed at machinery and inlet pipe. Indoor location

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100% conversion of fossil oil fired asphalt plant to bio oil

Project in numbers:� Conversion light oil fuel burners

24MW and 11MW to bio oil fuel,� Supplying heating oil station with

recirculation oil pumps,� Electrical heating system for oil

lines,� Compressor station for oil

atomization,� Compress air atomization pipe line,� New oil pipe lines, oil control and

shut off valves for burners. All material in stainless steel,

� Gas ignition burner (pilot) for lighting oil,

� Control system for electrical heating system and updating burner management system BMS.

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Oils properties

0,5%0,005%Water content

0,03%Ash content

0,04%Nitrogen content

0,041%Sulphur content

160oC68oCIgnition point

19oC-15oCFilter block temp./Melting point

60 mg KOH/gAcid value

35,7mm2/S at 40oC3mm2/S at 40oCViscosity

38,6MJ/kg42,8MJ/kgHigh heating value HHV

900kg/m3 at 60oC840kg/m3 at 15oCDensity

10,8mm2/S at 80oCViscosity

36,1MJ/kgLow heating value LHV

West energy oil

E20(0,05)

Light oil

EO1 E10

Parameters

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Bio-oil properties, melting point

� Oil heating system in silo,

� Direct heating system of oil in heat exchanger oil/water,

� Recalculation oil in piping system,

� Heating cable and thermal isolation on pipe lines and oil control valves.

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Heating system

Double wall oil tank. Indirect heating system water boiler and heat exchanger water/oil. System can be moved compact design in container.

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Bio-oil properties, aggressive corrosion

� Pipes are replaced to stainless steel,

� Valves, pumps, heat exchanger are made from stainless steel,

� Corrosion properties are increasing with temperature. Temperature in oil tank is reduced.

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Burner piping

Light oil line to burner. Before modification

Bio-oil and atomization line to burner. After modification

View of rotary kiln furnaces with 24MW oil burner

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Bio-oil atomization system

� Compress air system for oil atomization,

� Atomization increase the turn down ratio for the burner,

� Atomization air allow a lower temperature of oil, higher viscosityof oil but still good atomization.

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Thank you!

P.O. Box 557SE-611 10 NYKÖPING, SWEDEN

Phone +46 730 28 49 12 Fax +46 155 67 91 39

bjorn.forsberg@wtsab.comwww.wtsab.com