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CTU Clean Technology Universe AG

Your Partner for responsible waste treatment

CTU Clean Technology Universe AG

Scrubber systems

21.10.10 CTU Clean Technology Universe AG - Your Partner for responsible waste treatment

EMISSIONS (2000/76/EC)EMISSIONS (2000/76/EC)

Emissions: Dust 10 mg/Nm3

(daily average) VOC‘s (C) 10 mg/Nm3

HCl 10 mg/Nm3

HF 1 mg/Nm3

SO2 50 mg/Nm3

NOx (NO2 ) 200 mg/Nm3

Heavy metals: Cd,Tl 50 μg/Nm3 total Hg 50 μg/Nm3

Sb,As,Pb,Cr,Cu,Mn,Ni,V500 μg/Nm3 total

Dioxins and furans: 0.1 ng/Nm3 (TE)

plus halogens (Cl2 , Br2 , I2 ) and NH3 heat recovery


Particulate Removal Particulate Removal (dust, aerosols, heavy met.)(dust, aerosols, heavy met.)

• Low dust load:⇒

(venturi) scrubber, ring jet

• High dust load, insoluble dust:⇒

ESP (ElectroStatic Precipitator)⇒

Fabric/bag filter

• High dust load, salts, aerosols:⇒

(venturi) scrubber, ring jet⇒

WESP (Wet ESP)⇒

Aerosol filter


Wet Scrubbing (HCl, HF, SOx, Hg)Wet Scrubbing (HCl, HF, SOx, Hg)

• Quenching– With or without dust removal– Materials temperature and corrosivity

• Co-current vs. counter-current– Efficiency– Space

• Trays vs. random vs. structured packing– Absorption efficiency (NTSM)– Pressure drop– Partial load behavior– Plugging risk


QuenchingQuenching

Transition from hot and dry to cold and wet !

Advantages CTU system:• clear separation of MOC‘s• large liquid hold-up: inherent safety• gravity flow emergency water system• low pressure liquid pumps• no spray nozzles

– less plugging risk– less wear, less maintenance– less mist formation

but:• somewhat higher gas pressure drop


CoCo--current scrubbingcurrent scrubbing

HCl removal !

Advantages CTU system:• high efficiency packing• uniform flue gas temperature• high acid gas removal• low pressure drop• no spray nozzles, ideally wetted packing



CounterCounter--current scrubbingcurrent scrubbingSO2 and trace HCl removal !

Advantages CTU system:• high efficiency packing• lowest emission levels achievable• Stoichiometric chemical consumption• one to multi-stage arrangements• low pressure drop• no spray nozzles, ideally wetted packing



Low aerosol formation (example GEKAL)Low aerosol formation (example GEKAL)

• 2 lines of 75‘000 Nm3/h• Performance SO2

before: 98 % after: >99 %

• Performance SO3 (aerosols) before: 38 % after: 88 %

+0.00

+3.200

+1.60

+4.830

(bestehend gummiert)Achse Rohrstrebe Ø48,3x4

+5.735

+6.830

DN 150

N4

N13

N6

N10/11/12/14/15

DN 200

Trennhöhe

+3.322OK-Pratzen

Stutzenachse

Niederhalterost

Tragrost H=38mm

H=40mmMasche: 550x370mmMaterial: PP

Siehe Detail

• Modification of existing scrubbers (type Babcock, empty column with venturi type inlet, spray nozzles)


Plume PreventionPlume Prevention

• Requirements– % time without plume

• Ambient conditions– temperature– humidity

• Flue gas conditions– temperature

humidity (Ts)(to be influenced in scrubber)

Plume zone No plume zone

zone change

No plume

plume

almost plume

very short plume

Ambient temperature [°C]

r.h.[ %]


HCl Recovery from Waste IncinerationHCl Recovery from Waste Incineration

HCl Product

• Typical concentrations from HCl absorption:– Without boiler/ cooling: 15-20 wt% HCl– With boiler/ without cooling: 20-25 wt% HCl– With boiler/ with cooling: 25-30 wt% HCl

Water and HCl concentration in flue gasWater balance (including HCl distillation unit)

• HCl distillation:– Any concentration achievable 30...100 wt% HCl– Azeotropic solution: use or recycle to absorption– HCl Solution or HCl gas (at pressure 4-6 bara)– HCl quality sufficient for virtually all applications

• HCl recovery efficiency: up to 97-99%


Troubles with Mr. DeaconTroubles with Mr. Deacon

Deacon- Equilibrium:

2HX (g) + 0.5O2HX (g) + 0.5O2 2 (g) = X(g) = X2 2 (g) + H(g) + H22 O (g)O (g)

Whereas: X = F (Mm 19.0) (+2.9 V)Cl (Mm 35.5) (+1.4 V)Br (Mm 79.9) (+1.1 V)I (Mm 126.9) (+0.5 V)


Deacon equilibrium Deacon equilibrium -- ChlorineChlorine

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

800 850 900 950 1000 1050 1100 1150 1200 1250

Temperature [°C]

Perc

ent o

f Chl

orin

e in

ele

men

tal f

orm

1000 mg/Nm3

10'000 mg/Nm3

100'000 mg/Nm3

Parameter:Total Chlorine Content


Deacon equilibrium Deacon equilibrium -- BromineBromine

0

10

20

30

40

50

60

70

80

90

100

800 850 900 950 1000 1050 1100 1150 1200 1250

Temperature [°C]

Perc

ent o

f Bro

min

e in

ele

men

tal f

orm

10 mg/Nm3

100 mg/Nm3

1000 mg/Nm3

10'000 mg/Nm3

Parameter:Total Bromine Content


Deacon equilibrium Deacon equilibrium -- IodineIodine

0

10

20

30

40

50

60

70

80

90

100

800 850 900 950 1000 1050 1100 1150 1200 1250

Temperature [°C]

Perc

ent o

f Iod

ine

in e

lem

enta

l for

m

10 mg/Nm3

100 mg/Nm3

1000 mg/Nm3

Parameter:Total Iodine Content


Relevant Parameters for Deacon Relevant Parameters for Deacon

• Temperature

• Concentrations of:

– Halogen equilibrium --> elemental form

– O2 equilibrium --> elemental form

– H2 O equilibrium --> hydrogenated form

• Kinetics (from which side equilibrium is approached, how far is it reached)


Comparison Comparison ClCl -- Br Br -- II

Total amount of halogen required for a level of approx. 500 mg/Nm3 of elemental halogen in the flue gas

80'000

4'000600

010'00020'00030'00040'00050'00060'00070'00080'00090'000

100'000

Cl Br I

Total halogen [mg/Nm3]


Conclusions for incinerationConclusions for incineration

• Determine amount of Halogen relevant for Deacon: – Halogenated organics vs. salts, stability of salts

• Determine combustion parameters– Temperature, Oxygen, Water

• Determine possible amount of elemental Halogen– Deacon, kinetics, safety margins, additives

• Design plant accordingly– Corrosion, elemental halogen removal


HalogenideHalogenide scrubbingscrubbing

• (Semi-) dry process ?

• 1, 2, 3, multi-stage ?

⇒

other requirements ?⇒

limited efficiency !

⇒

acid recovery ?⇒

neutralisation ?⇒

halogen scrubbing ?


Halogen scrubbingHalogen scrubbing

• Absorption• Hydrolysis (example Cl):

ClCl 22 + H+ H 22 O O = = HOClHOCl + H+ H++ + + ClCl--

• Reduction to Halogenide: NaHSONaHSO 33 + + NaOClNaOCl + + NaOHNaOH = Na= Na 22 SO4 + SO4 + NaClNaCl + H+ H 22 OO

⇒

Solubuility⇒

Sensitivity to pH

⇒

Reducing agent example: - Sodumbisulphite - Chlorine


Conclusions for scrubbingConclusions for scrubbing

• High efficiency scrubbing columns required⇒

mass transfer, pressure drop• Check all parameters influencing reactions

⇒

temperature, pH, other impurities, etc.• Select appropriate reducing agent • Design scrubbing system according to requirements

⇒

number of stages, concentrations, control⇒

corrosion control, scaling control, utilities


Flue Gas Cleaning Flue Gas Cleaning -- process comparison 2process comparison 2

(Semi)Dry Process Wet Scrubber Combined

· Limited HCl/SO2

removal

· Any given HCl/SO2

removal

· Any given HCl/SO2

removal

· No elementary Cl2removal

· Elementary Cl2removal

· Elementary Cl2removal

· Dust removal · Limited dust

removal except

with WESP

· Dust removal

· Dioxine removal

possible

· No dioxine removal

except with SCR

· Dioxine removal

possible

· No effluents · Effluents · Limited effluent or

effluent -free

· Solid waste · No solid waste · (less solid waste)


Dust: dry process/ (W)ESP: < 10 mg/Nm3

venturi type scrubber 60-95% reduction (acc. inlet)HCl: dry process: 98-99% reduction

wet scrubber: < 10 mg/Nm3 easily achievedSOx: dry process: 85-90% reduction

wet scrubber: < 10 mg/Nm3 easily achievedNOx: SNCR: 50-80% reduction

SCR: 70-80 mg/Nm3

NH3 : dry process: no reduction(from DeNOx) wet scrubber: < 5 mg/Nm3

SCR: < 5 mg/Nm3

Heavy metals: removal generally as dust, except Hg, Cd, ZnCl2 removal in acid scrubber or act. carb.

Dioxins/ furans: dry process/SCR: < 0.1 ng/Nm3 (TE) possible

Flue Gas Cleaning Flue Gas Cleaning -- process comparison 3process comparison 3


Flue Gas Cleaning Flue Gas Cleaning -- process comparisonprocess comparison

Semi-dry & dry process

Wet scrubber process

SCR selective catalytic red.

Dust, HM + (+) neg.

HF, HCl (+) + -

Cl, Br, I - + -

SOx (+) + neg.

NOx - - +

NH3 (from DeNOx) neg. + +

Hg + (+) -

PCDD, PCDF + - +


Flue Gas Cleaning KVA Flue Gas Cleaning KVA WeinfeldenWeinfelden


Flue Gas CleaningFlue Gas Cleaning KVA KVA WeinfeldenWeinfelden

• VFlue Gas = 65‘000 Nm3/h

• HFclean < 1 mg/Nm3

• HClclean < 10 mg/Nm3

• SOxclean < 50 mg/Nm3

• Dustclean < 1 mg/Nm3


Thank you for your attention!

CTU Clean Technology Universe AGBürglistrasse 29CH- 8400 WinterthurTel: +41 52 557 52 52Fax: +41 52 557 52 [email protected] - www.ctu.ch

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