sulphur recirculation for reducing corrosion and ......gÖtaverken miljÖ ab – a babcock &...

GÖTAVERKEN MILJÖ AB – a Babcock & Wilcox Vølund company

Sulphur Recirculation CUTNOX NextBAT

Sulphur Recirculation for reducing corrosion and increasing electrical efficiency in WtE boilers

Dr. Sven Andersson

Götaverken Miljö AB, Sweden– a Babcock & Wilcox Vølund company


Sulphur Recirculation CUTNOX NextBATSulphur RecirculationOperating principlesFull-scale operationAshes and depositsEmissionsCorrosion rates

Ash

Sulphur Recirculation

Sulphur in fuel


Sulphur Recirculation CUTNOX NextBATCUTNOXOperating principlesFull-scale installationNOx reduction


Sulphur Recirculation CUTNOX NextBATNextBATHCl / SO2 / NH3HgDioxinsNOxFine particlesEnergy recovery

CUTNOX™ in combination with SNCR

SulphurRecirculation


Sulphur Recirculation CUTNOX NextBATElectricity production in WtEis limited by superheater corrosion

Biomass or wastefired boiler




Ash

Sulphur mass balance

Sulphur in fuel

Flue gas




Sulphur dosage

Ash

Flue gas

Sulphur dosage inhibits corrosion

Sulphur in fuel

Higher SO2 concentration:Alkali chlorides → alkali sulphates(corrosive) (non corrosive)




Ash


Sulphur in fuel

Sulphur Recirculation for High Efficiency, Low Corrosion WtE


Higher SO2 concentration:Alkali chlorides → alkali sulphates(corrosive) (non corrosive)



Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

The effect of chromium depletion on chromia forming steels

(Cr,Fe)2O3 Fe2O3 + K2CrO4 + HClO2 + H2O + KCl

Before After

Chromate formed

KC

lK

2CO

3K

2SO

4Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

304L (Fe20Cr10Ni), 5% O2 + 40%H2O, 600°C

O2 (no salt)

Pettersson, J., Folkeson, N., Johansson, L.-G., Svensson, J.-E., The Effects of KCl, K2SO4, and K2CO3 on the High Temperature Corrosion of a 304-Type Austenitic Stainless Steel. Oxidation of Metals, 2011. 76(1): p. 93-109.



Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4


(Cr,Fe)2O3 Fe2O3 + K2CrO4

O2 + H2O + K2CO3 + CO2

Before After

Chromate formed

Chromate formed

KC

lK

2CO

3K

2SO

4Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

304L (Fe20Cr10Ni), 5% O2 + 40%H2O, 600°C

O2 (no salt)




Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4


(Cr,Fe)2O3 Fe2O3 + K2CrO4O2 + H2O + K2SO4 + SO2

Before After

Chromate formed

Chromate formed

KC

lK

2CO

3

No chromate formedK

2SO

4Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Exposure time (h)

0 24 48 72 96 120 144 168

Mas

s ga

in (m

g/cm

2 )

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

304L (Fe20Cr10Ni), 5% O2 + 40%H2O, 600°C

O2 (no salt)




SNCR

Dosage

Oil burn.

Grate

Super-Heaters




Full-scale tests at Renova P5 (Göteborg)

V

Dosage

Furnace

Super-Heaters ESP Eco

SO2-stage

HCl-stage

Con

dens

ing-

scru

bber

Bag houseRe-heat

Stac

k

Sulphuric acidAtomization air

H2O2

Flue gas recirculation

22 ton waste/h




Full-scale tests at Renova P5 (Göteborg)

V

Dosage

Furnace


SO2-stage

HCl-stage

Con

dens

ing-

scru

bber

Bag houseRe-heat

Stac

k

Sulphuric acidAtomization air


22 ton waste/h

SO2

H2SO4

SO2

H2O2




1000 h Reference (normal operation)

V

Furnace

ESP Eco

SO2-stage

HCl-stage

Con

dens

ing-

scru

bber

Bag houseRe-heat

Stac

k

H2O2

1000 h Reference: SO2 in boiler = 270 mg/m3 (n,dg)

SO2 in boiler




1000 h Recirculation: SO2-setpoint

V

Furnace

ESP Eco

SO2-stage

HCl-stage

Con

dens

ing-

scru

bber

Bag houseRe-heat

Stac

k

H2O2

1000 h Reference: SO2 in boiler = 270 mg/m3 (n,dg)1000 h Recirculation: SO2 in boiler = 720 mg/m3 (n,dg)

SO2 dosage

SO2 in boiler




Sampling and measurements

Boiler ash ESP ashAsh samplingDosage

Furnace


SO2-stage

HCl-stage C

onde

nsin

g-sc

rubb

er

Bag houseRe-heat

Stac

kAcid dew point measurements

High temp corrosion probe 24 h and 1000 h Impactor and deposits probe

AMESA continuousdioxin sampler

Emission meas.




Deposit rate (g/m2,h) decreased with SO2


Furnace


SO2-stage

HCl-stage C

onde

nsin

g-sc

rubb

er

Bag houseRe-heat

Stac




Emission meas.Acid dew point measurements

0

10

20

30

40

50

60

0 200 400 600 800 1000

Dep

osit rate (g/m

2 ,h)

SO2 (mg/Nm3)

Ref

Recirk

Impactor and deposits probe

Short term meas.




Fly ash Cl/S vs SO2 from 3 different plants


Furnace


SO2-stage

HCl-stage C

onde

nsin

g-sc

rubb

er

Bag houseRe-heat

Stac




Emission meas.

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 200 400 600 800 1000

Cl/S

SO2 after boiler(mg/Nm3 t.g.)

Fly ash

Reference

Optimisation

Recirculation

TAMARA

Plant B




Acid Dew point Temperature (ADT)


Furnace


SO2-stage

HCl-stage C

onde

nsin

g-sc

rubb

er

Bag houseRe-heat

Stac




Emission meas.


Lancom 200 Acid Dewpoint Monitor

Result: No measurable ADT

Detection limit: 110-120°C



Dioxins in the flue gas: ¼ less


Furnace


SO2-stage

HCl-stage C

onde

nsin

g-sc

rubb

er

Bag houseRe-heat

Stac




Emission meas.


0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

Ref 1‐3 Ref 4 Recirk 1‐3

I‐TEQ

ng/Nm3@

11O2

Ref Ref Recirc




time (days)

Mon

21

Tue

22

Wed

23

Thu

24

Fri 2

5

Sat 2

6

Sun

27

Mon

28

Tue

29

Wed

30

Thu

01

Fri 0

2

Sat 0

3

Cl/S

(HC

l, SO

2)

0.01

0.1

1

10PC

DD

/F (T

EQ n

g/N

m3 , 1

1% O

2)

0.01

0.1

1

10


Dioxins

Cl/S

Start-up

Dioxins in raw gas ~ emission limit!

Pilot tests at KIT – Dioxin reduction




Stack values (% of Emission limit)


Furnace


SO2-stage

HCl-stage C

onde

nsin

g-sc

rubb

er

Bag houseRe-heat

Stac




Emission meas.Emission meas.





Furnace


SO2-stage

HCl-stage C

onde

nsin

g-sc

rubb

er

Bag houseRe-heat

Stac




Emission meas.High temp corrosion probe 24 h and 1000 hImpactor and deposits probe

Corrosion probes in the superheater position




Corrosion probes in the superheater position

(wt%) Cr Ni Mn Si Mo Fe nCr/nFe Add. elements16Mo3 - - 0.6 - 0.3 99.1 0 -

Sanicro 28 27.0 31.0 2.0 0.6 3.5 34.5 0.8 Cu: 1Inconel 625 22.0 58.0 0.5 0.5 9.0 5.0 4.4 -

Air inlet

Air outlet16Mo3, Sanicro28, Inconel625

Wall

450°C

525°C




16Mo3 - Photograph - 525 °C

Reference16Mo3

Sulphur Recirculation16Mo3




Corrosion rate at material temp 450°C (1000 h)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

Sanicro 28 Inconel 625 16Mo3

Materialfö

rlust (µ

m/h)

Ref

Recirk

Cor

rosi

onra

te (µ

m/h

)

RefRecirc




Inconel 625 - SEM/EDX images - 450°C

1000 h ReferenceCorrosion attack

1000 h RecirculationUnaffected surface

Beläggning

Deposits

SEM EDX map for chlorine

Deposits




Sanicro 28 - 1000h

1000 h Recirculation1000 h Reference

450°C

525°C




1000 h Corrosion rate measurements

mm/year

Sulphur recirculation enableshigher steam data




Summary

Boiler ash: ESP ash:Less Cl and more SDosage

Furnace


SO2-stage

HCl-stage C

onde

nsin

g-sc

rubb

er

Bag houseRe-heat

Stac

kNo detectable acid dew point

Lower high temp corrosion at 450 and 525 ºC material tempLess deposits and particles

1/4 Less dioxins

Emissions unchanged(lower CO and NH3)




NOx primary measure: CUTNOX

Furnace

Primary air

Waste

Bottom ash


Secondaryair

After Burning Chamber

Grate

CUTNOX: air + water

12 3 4

Lower temp. and increased mixing at λ<1 promote formation of N2 and reduce formation of NO

CUTNOX



Test at TAMARA: Pilot grate fired furnace (0,5 MWth)0.

187

0.07

7

2.24

0

0.95

0

0.0

0.5

1.0

1.5

2.0

2.5

V7 V8 V9 V10

TOC

(%)

393

341

2429

1713

0

500

1000

1500

2000

2500

3000

V7 V8 V9 V10

Cl (

mg/

kg)

0.37 0.40

76.2

5

36.5

0

0.1

1.0

10.0

100.0

V7 V8 V9 V10

PCD

D/F

TEQ

(ng/

kg)

Less TOC, Cl and PCDD/Fs in the bottom ash

H2O-jet H2O-jet H2O-jet

CUTNOX



NOx: First commercial CUTNOX at Renova (SE)Preliminary results from CUTNOX ON/OFF tests: Optimisation in progress

NOx mg/Nm3 (dg, 11% O2)

Time

CUTNOX ON OFF ON OFF ON

OFF = 92 (mg/Nm3 d.g.)

ON = 60 (mg/Nm3 d.g.)

Corresponding to34% NOx reduction

CUTNOX




Condensation+ Heat pump

ADIOX®

WESP

Multi-scrubber

NextBAT® flue gas treatment

Dust removalDry/SW/-

reactor

HCl+NH3

SulphurRecirculation SO2MERCOX™+SO2

NextBAT



SO2

Multi-scrubber

HCl+SO2 removal


reactor

HCl+NH3

Wet scrubbers yieldextremely low emission values: Insensitive toHCl/SO2 ratio

Waste water free:Dry or semi-wet+ slip scrubber

Cl- + SO42-

to water recipient:Wet scrubber

NextBAT




WESP

NOx + NH3

NH3

SNCR:Lower NOx values calls for increased NH3 dosage and slip

Solution• SCR• SNCR + CUTNOX

NextBAT



WESP

Dust / fine particles

Dust removal

ProblemPM2.5 in ambient air causes premature death of 350 000 EU citizens per year.

In many urban environments, the ambient air levels of PM2.5 are higher than stipulated by EU directives.

SolutionDust concentrations < 1 mg/Nm3 (10% ofemission limit) can be reached by:

• Bag house filter

• ESP + scrubber integrated WESP

NextBAT



Dust: Scrubber Integrated WESP

- New scrubber integrated WESP (Wet Electro Static Precipitator) developed by Götaverken Miljö and AWS Corp (IT).

- Fabricated in corrosion resistant conductive FRP

- Cooled condensing collector

• All clean gas dust measurements <0,3 mg/Nm3 dg.• Mean removal efficiency >99%

NextBAT



PCDD/F removal

Dust removal• Bag house filter + carbon injection

+ ADIOX for Memory Effect minimisation

• ESP + ADIOXADIOX can be incinerated after use –thereby taking dioxins out of the eco-cycle

ADIOX®

NextBAT

Gas Plastic

C



•

•

•

• ••

•

••

•

••

••

•

•

•

•

•

•

•

•

•

•••

•

•

PCDD/F removal: ADIOX®

- Dioxin absorption in carbon filled polymer- ADIOX material in packings and demisters- If required a separate ADIOX absorber unit

- Always on-line to absorb dioxin- Efficient also during plant start-up

Linköping dry ADIOX absorber

Scrubber interior

ESP+ADIOX

NextBAT



HgHg° + Hg(II)

using activatedcarbon• Bag house filter + carbon injection

is normally sufficient for Hg removal

• MERCOX in case of very high Hg loads or very low emission values

Hg° using MERCOX

Hg(II) in HCl stage

NextBAT




Energy recovery


- Increased energy recovery by some 20-25 % by ocondensation with heat pumps

Vestforbraendingabsorption heat pump

NextBAT



Energy efficiency: Sulphur Recirculation

SO2

H2SO4

SO2

H2O2


NextBAT



Hg: Sakab Hazardous waste incinerator, Sweden

Multifunctional MercOx- and ADIOX scrubberfor Hg°, Hg(ox), HCl, SO2 and dioxin removal

Waste water free!

NextBAT



Filborna, Helsingborg (SE)

Units Afterboiler

Before scrubber

Emissionguarantee

Emissionexpected

HCl mg/Nm3 2000 45 5 ~ 1SO2 mg/Nm3 1000 50 25 ~ 1HF mg/Nm3 30 1 0.5 ~ 0.1PCDD/Fs ng/Nm3 10 0,05 0,05 ~ 0.02

District heating

AbsorptionHeat pump

SO2 & HF removal

HCl & NH3 removal

Heat recovery

Emissions:

NextBAT




MERCOX™+SO2


ADIOX®

WESP

Multi-scrubber


reactor

HCl+NH3


NextBAT

Conclusions



Conclusions

• Reduced NOx concentration / NH3 consumption

• Less TOC, Cl and PCDD/Fs in the bottom ash

• Smaller variations in temperature and steam flow

CUTNOX



Conclusions

• Potential for sulphate waste water free operation

• Less dioxins, deposits and ashes

• More electricity production orless corrosion

Sulphur recirculation




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sulphur recirculation for reducing corrosion and ......gÖtaverken miljÖ ab – a babcock &...

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