SODIUMBICARBONATE FOR

FLUE GASTREATMENT

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Brunner Mond is one of theworld’s leading manufacturers and suppliers of Soda Ash,Sodium Bicarbonate andassociated products.

We have manufacturing plants in Northwich,Cheshire; in Delfzijl, The Netherlands and atLake Magadi in Kenya. We also operate atransportation terminal at Durban, South Africa.Our parent company, Tata Chemicals Ltd, hasSoda Ash and Sodium Bicarbonate plants inthe Gujarat region of India.

The combined Brunner Mond/Tata ChemicalsGroup produces three million tonnes of SodaAsh and 250,000 tonnes of SodiumBicarbonate every year.

Our products are essential in the manufactureof a wide range of staple and specialist goods,with more than 1,500 customers worldwide asdiverse as glass makers, bath additiveproducers, sugar extractors and suppliers ofhaemodialysis treatments. All our products aresupplied from all our operations under theinternationally recognised quality standardISO 9001:2000.

Sodium Bicarbonate is a versatile product usedin the manufacture of a wide variety of goods ineveryday use.

We are the second largest producer ofSodium Bicarbonate in Europe with twomanufacturing facilities in the UK, one of whichis dedicated to Briskarb®, and a brand newplant in the Netherlands.

We produce 50 variants of graded productwhich service a diverse range of applicationsincluding environmental, pharmaceutical,medical, personal care products, food andanimal nutrition.

FLUE GAS TREATMENT (FGT)We are leading experts in all aspects of SodiumBicarbonate technology and applications. Oneof the many areas we service is the fast-growing FGT sector.

Briskarb® is tailor-made by Brunner Mond foruse in this sector. We understand that everyfacility is unique and has specific emissionchallenges. We are equipped and willing towork with our customers to maximise theeffectiveness of Briskarb® in their emissioncontrol process.

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Briskarb® – Brunner Mond’s Flue Gas Treatment reagent 4How acid gases are treated 5The benefits of Briskarb® 6Effectiveness 7Factors affecting efficiency 8Why Briskarb® is better 8How much Flue Gas residue will you create? 9Model for usage and disposal 9Can Briskarb® be used in your industry? 10Questions & answers 11

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BRISKARB® – BRUNNER MOND’S FLUE GAS TREATMENT REAGENT

Acid flue gases are produced duringwaste incineration and many otherindustrial processes involvingcombustion.It is important to manage thesegases effectively to comply withenvironmental legislation.Briskarb®, a special grade of Sodium Bicarbonate

manufactured and supplied by Brunner Mond, is a

proven, effective reagent for the neutralisation of such

gaseous emissions.

THE LEGISLATIONWaste Incineration Directive 2000/76/EC regulates

all environmental discharges into air, soil and

water resulting from incineration and co-incineration

of waste.

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Briskarb® mixes and reacts with the flue gases

Filtered neutralised gas passes to atmosphere in compliance with 2000/76/EC

Feed waste

Filter

Stack

Bottom ash

Acidgases

Furnace

Fly ash

Waste heat boiler

FGT residue

Briskarb® dry injection

HOW ACID GASES ARE TREATED

Combustion processes generate acid gases in varying

concentrations. Municipal and clinical waste incinerators

generate relatively high concentrations of hydrogen chloride

(HCl), while glass furnaces and power generators using fossil

fuels predominantly produce oxides of sulphur (SOx).

Legislation controls the release of these gases into the

atmosphere. It stipulates maximum emission limits and

requires the operator to apply Best Available Techniques (BAT).

European Directive 2000/76/EC on the incineration of

waste (see box on page four) sets out the following limits:

AIR EMISSION LIMIT VALUES

DAILY AVERAGE

Hydrogen chloride (HCI)

Sulphur dioxide (SO2)

Hydrogen fluoride (HF)

Nitrogen oxides (NOx)

Total dust

Gaseous and vaporousorganic substances expressedas total organic carbon

10 mg/m3

50 mg/m3

1 mg/m3

200 mg/m3 (>6te/hr)

400 mg/m3 (<6te/hr)

10 mg/m3

10 mg/m3

Limit*

* dry gas 273°K, 101.3kPa, 11% O2

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Briskarb® neutralises acidgases much moreefficiently than othercommonly used dryinjection reagents, e.g. lime (Ca(OH)2) andsodium carbonate(Na2CO3).When Briskarb® is dry injected into hot flue

gases there is rapid thermal decomposition,

creating a high surface area sodium

carbonate. The surface area can increase

by up to eleven-fold, depending on

process conditions.

This fresh, high surface area sodium

carbonate reacts quickly and efficiently with

the acidic components of the gas.

2 NaHCO3 Na2CO3 + CO2 + H2OHEAT

X 1,000 MAGNIFICATION

X 10,000 MAGNIFICATION

HEAT

HEAT

Scanning Electron Microscope (SEM)images showing this effect. The images on

the right hand side clearly have moreporosity and therefore surface area

THE BENEFITS OF BRISKARB®

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NEUTRALISATION REACTIONS Focusing on the two main acid gas components, the reactions with Briskarb® are:

NaHCO3 + HCl NaCl + CO2 + H2O

2 NaHCO3 + SO2 + 1/2 O2 Na2SO4 + 2 CO2 + H2O

2 NaHCO3 + HF NaF + CO2 + H2O

EFFICIENCYWith 100% efficiency the following would occur (calculated from the

stoichiometry of the above neutralisation reactions):

2.3 kg NaHCO3 neutralises 1kg HCl2.6 kg NaHCO3 neutralises 1kg SO2

Reductions of up to 99% in HCl emissions and over 95% in SO2 emissions can

be obtained. At such high removal efficiencies typical stochimetric ratio of 1.25

is achieved.

STOICHIOMETRIC RATIO STOICHIOMETRIC RATIO

% HCI REMOVED % SO2 REMOVED

* Stoichiometric Ratio =quantity of reagent actually used

quantity of reagent theoretically required (100% efficiency)

EFFECTIVENESS

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The key business benefits of Briskarb® are:

Enhanced environmental performance – Briskarb® removes acid gases very effectively,

resulting in cleaner flue gases from the combustion processes.

It is more cost effective – Lower consumption and residue formation makes Briskarb® a very

cost effective option for FGT.

Lower capital investment is needed – A simple, dry powder injection system is needed for

Briskarb®.

Compared with other alkaline reagents for the neutralisation of acid gases, Briskarb® gives:

1. Lower consumption of reagent through better reactivity – typically a stoichiometric

ratio of 1.25 for Briskarb® which is substantially lower than other reagents.

2. Lower levels of HCl and SO2 – enabling efficient compliance with Waste Incineration

Directive limits.

3. Reduced HCl and SO2 emission spikes – rapid reaction times enable compliance

with half-hourly averages.

4. Lower disposal costs – less FGT residues are generated.

5. Greater efficiency with dry once-through system – no need for recirculation.

6. Better thermal efficiency – no need for water injection to control gas temperatures.

7. Effective over a wide temperature range (140° - 400°C) – same consumption

regardless of gas temperature.

8. Reduced maintenance – residues from Briskarb® reaction are non-scaling.

9. Ease of handling – Briskarb® is non-hazardous and non-irritant.

FACTORS AFFECTING EFFICIENCYTemperature

Briskarb® is effective over a wide temperature range:

Below about 140°C the reaction rate becomes too slow. Above 400°C sintering of

sodium carbonate occurs and the benefit of a high surface area is reduced, decreasing

the effectiveness of the reaction.

Reaction Time

The reaction occurs within seconds. Longer contact between the reagent and the gas

increases efficiency. This could be achieved for instance by using a bag filtration system.

The reactivity of Briskarb® after thermal activation means that there is no need for

recirculation of flue gas treatment residues.

Particle Size

The particle size can influence the effectiveness of reaction because fine powders react

more efficiently than coarse crystals.

Brunner Mond can provide Briskarb® Premium, a pre-milled fine powder with good flow

characteristics for direct injection, giving optimum efficiency without the need to mill.

Alternatively, an in-line mill can be installed to reduce the average particle size to achieve

optimum efficiency.

400°C140°C

WHY BRISKARB® IS BETTER

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Using Briskarb® means less FGT residues.

The following table shows the solid FGT residues that would

be generated per tonne of reagent used for neutralisation of

either HCl or SO2 compared with the most commonly used

alternative reagent.

BRISKARB® HYDRATED LIME

217 kg/hr Briskarb®

(Stoichiometric ratio 1.25)231 kg/hr Lime

(Stoichiometric ratio 3)

HCl 1000 mg/Nm3

SO2 200 mg/Nm3

Gas flow rate 65kNm3/hr

HCl 10 mg/Nm3

SO2 50 mg/Nm3

HCl 1000 mg/Nm3

SO2 200 mg/Nm3

Gas flow rate 65kNm3/hr

Lime residues272 kg/hr

Briskarb® residues168 kg/hr

FilterUnit

The above calculations assume a 100% reaction.

REAGENT ACID GAS RESIDUES

Briskarb® HCI 0.7 tonnesSO2 0.8 tonnes

Lime HCI 1.5 tonnesSO2 1.8 tonnes

HOW MUCHFLUE GASRESIDUE WILLYOU CREATE?

A MODEL FOR USAGE AND DISPOSAL

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CAN BRISKARB® BE USED IN YOUR INDUSTRY?

Thermal treatment of waste

Briskarb® is used in the treatment of gases from metalsmelting operations such as aluminium.

Emissions challenges in this industry include theremoval of acid gas species such as HCl and HF -Briskarb® reduces the concentrations of these speciesefficiently. Briskarb® can also treat the acid chloridespecies associated with secondary aluminiumproduction. As an additional benefit, the resultantsodium chloride can be recovered by filters and thenre-charged to the furnace.

Metal processing

The adaptability of Briskarb® means that it canmeet the specialist abatement needs of manydifferent chemical manufacturing processes.

Chemical manufacture

Use of biomass in power stations as a carbon-neutral fuel is increasing.

Briskarb® is used in the FGT systems of suchfacilities.

Biomass

Burning of alternative fuels such as tyres in cementkilns results in the generation of acid gases whichare effectively removed with Briskarb®.

Electrostatic precipitators are commonly used inthis industry because of the relatively high flue gastemperatures. Briskarb® can be injected into theflue gas duct upstream of the precipitators toprovide effective abatement.

Cement kilns

Briskarb® is a very effective reagent for thetreatment of acid gases arising from glass furnaces.

The sodium-based residues can be recycled intothe glass furnace, making Briskarb® a veryeconomical option.

Glass manufacture

The excellent HCl abatement properties of Briskarb®

make it an attractive choice for municipal and clinicalwaste treatment plants, where variable amounts ofplastics and other chlorine-containing materials cancause problematic spikes in HCl emissions.Briskarb® is compatible with the high combustiontemperatures used in specialist plants for the treatmentof hazardous waste.Briskarb® has become the reagent of choice for bothsmall- and large-scale plants disposing of animalcarcasses and by-products because of the simplicityand flexibility of dry, once-through abatement systems.

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1. Will I need new equipment when Iswitch to Briskarb®?No, the facilities for dry reagents can be usedfor Briskarb® with only minor adjustments tosettings.

2. Will I need new investment ifemission limits become tighter?No, more stringent limits on acid gases canbe met by simply injecting more Briskarb®.

3. What is the minimum suitable fluegas temperature for Briskarb®?A minimum temperature of 140°C isrecommended. Briskarb® consumption doesnot vary with temperature.

QUESTIONS & ANSWERS

4. Is Briskarb® a proven technology?Yes, the use of Sodium Bicarbonate in fluegas treatment is considered as Best AvailableTechnique (BAT). There are over 200reference sites worldwide.

5. Is Briskarb® safe to use?Yes. Briskarb® is classified as non-hazardous.

6. What is the classification of theFGT residue?This depends on the type of combustionprocess involved. European Waste Catalogue(EWC 2000) sets out the classifications fordifferent industries.

7. What is the CO2 contributionwhen using Briskarb®?Briskarb® will not measurably increase yourCO2 emissions.

8. Will Briskarb® give me anyoperational cost savings?Yes, in many cases the total cost of reagentplus residue disposal will be lower comparedto other reagents such as lime.

9. How can I calculate the totalbenefit of switching to Briskarb®? The Brunner Mond team of experts can help you to fully assess Briskarb® in yourapplication, carry out trials and optimisationwork and calculate total benefits.

Call us on 01606 724 175 to discuss your needs with Brunner Mond’s experts, or e-mail us at briskarb@brunnermond.com

Brunner MondPO Box 4, Mond HouseNorthwich, Cheshire CW8 4DTTel: +44 (0) 1606 724000 Fax: +44 (0) 1606 781353 briskarb@brunnermond.com

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