Coal Flaring

8/9/2019 Coal Flaring

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September 2007

Harworth Power Ltd

CMM Flaring


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Harworth Power

Part of UK Coal PLC -Ex Nationalised British Coal

UK Coal 4000 employees, 14Mt capacity, surface and deep mines

VAM oxidation technology trialled on an operating coal mine

CMM utilised in boilers since the 1960s

CMM utilised in gas turbines and gas engines since 1991

CMM utilised in high efficiency gas engines since 2000 (30MWe installed)

CMM destructed in enclosed flares since 2004 (7 flares installed)

Part of the UK ETS since 2001, 2.3Mt CO2e verified (3.9Mt total)

Separate unit specialising in assisting mines maximise capture, qualityand utilisation engineers deployable to assist in design and

implementation

Typical capture rates 40% - 60% of coal face district gas

Typical gas quality 30% to 50% methane

All gas is utilised in generators, boilers or flared

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Key Issues in Flaring of CMM

Gas is NOT utilised but destroyed

Safety

Capital Cost

Operating Cost

Equipment Delivery Will the Government allow gas to be flared rather than

utilised?

Ideal scenario in the US distributed remote gas sourceswithout realistic or economic means us using heat,electricity or low quality gas near the well head.

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Coal to CMM Flaring

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Coal Mining General Data

KellingleyColliery

ThoresbyColliery

WelbeckColliery

HarworthColliery

StillingfleetMine

Depth (m) 900 750 700 850 700

Tonnage (Mt) 1.455 Mt 0.829 Mt 0.868 Mt Mothballed Mine Closed Mine

Seam Thickness 2.1 1.85 1.85 2 3

Gas M3/tonne 5.3 5.2 5.0 6.2

Gas Typical FlowRate (l/s)

400 600 250 - 350 350 - 450 650 850 950

Gas TypicalConcentration

40 50% 30 40% 35 45% 45 55% 80%

Utilization /destruction

2x 20,000 lb/hrdry sat steam

boilers

3x 1.4MWe gasengine generators

1x 2,000 Nm3/hrenclosed flare




boilers


2 x 2,000 Nm3/hrenclosed flare


boilers



18MWe CCGT

4x 3MWe gasengine generators

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Overview

Gas Flaring.Technology:Destruction of drained methane gas through combustion in

a gas flare. 2000 Nm3

/hr destruction capacity per flare.

Benefits:A low capex cost technology with a short manufacture and installation lead time.Simple, low cost and reliable to operate, gas flaring offers a very high potential for significant GHG reduction.Low maintenance requirements.Installation Requirements:80 litres/s pure methane flow at 20% purity or above,Methane drainage infrastructure already in place, Suitable flame arrestor technology installed to prevent flame propagation into the mine.Mine Suitability:A disciplined drainage approach ensuring that methane isonly drained above 20% purity.

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Flare P&I Diagram

2000 Nm3/hr methane destruction capacity

>27% CH4 for reliable flare start

Flare will operate down to 20% CH4

Automatic control

Internet Remote Monitoring and Control

Skid mounted for ease of installation

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Importance of Gas Purity

Gas will not burn or explode outside of the flammablerange

Gas will not allow an existing flame to propagate into themine outside of the flammable range

Multiple failsafe concentration transducers automatically

stop supply of gas to extraction pumps and flare Careful consideration of system T90 reaction period

Only effective means of protection against lightning as an

ignition source

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Flammability of Methane / Air at Atmospheric Pressureand Temperature

The flammability of mixtures of Methane and Air

C

Capable of formingflammable

mixtures with airper se.

FlammableRegion

Coward Diagram

20

15

10

5

0

B

E

F

D

Not capable offorming

flammable

mixtures with air

Oxygen

Concentration

255 10 15 20Methane Concentration

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Hierarchy of Explosion Prevention and Mitigation

1. Prevent formation of flammable atmosphere measureconcentration and stop flow

2. Prevent exposure of ignition source to flammableatmosphere necessary for destruction / combustion

3. Prevent propagation through flammable mixture use ofequipment/burner design, flame arresters and valves

4. Dissipate energy bursting discs / relief valves / vents

5. Prevent of release of explosion energy vessel and

pipework design

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Flame Propagation in Pipework

Flame Speed

Point ofIgnition

50 x Pipe Diameters

Direction of flame propagation

Deflagration

Detonation

Overdriven DetonationChoked flame speed (Mach 1)

M = 1

x

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Specific Flare Safety Features

Safety risk assessments carried out fordesign and operation to prevent flashback

HAZOP Hazardous Area Classification Flame Arrester suitability assessment Multiple redundancy and safety features Gas quality monitoring and oxygen inter-

trip PLC controlled with certain high integrity

functions duplicate hard wired

Burner velocity design to preventflashback

Temperature sensing to prevent flamearrester burn through

Purge for start-up

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September 2007

Thank you

Neil ButlerTechnical Director

44-7798-571612

[email protected]


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USA Coal Mine Methane Conference

The modern high temperature flareSt Louis, 26thSeptember 2007

www.clarke-energy.com


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Cla rk e Ener gy supp l i es, i nst a l ls and m a in t a ins HAASE f lar es

15www.clarke-energy.com


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Cheap and d i r t y v e rsus st a te -o f - t he -a r t

60% CH4destruction

99.9% CH4destruction



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HAASE f l a re t yp es h i gh t em pe ra tu re con t i nuou s du t y an d l o w t e m p er a t u r e e m er g e n cy

0.3s retention

99.9% CH4 destruction

CH4 down to 25% or lowerwith propane assist atignition

Turn down 5:1 or greater

HT type LT type 2 LT type 1

www.clarke-energy.com17


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HAASE l i n i ng 1 0 y ear gu a ran t ee



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Cold s ide l i n in g f i x ing



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Germ an and UK regu la t i ons

TA-Luft UK

NOX 200 mg/m3 150 mg/m3

CO 100 mg/m3 50 mg/m3

Temperature 1,200oC (1830oF) 1,000oC (2200oF)

(Reference 3% O2by vol. in exhaust gas)



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Natu r a l l y ven t i l at ed and f an ven t i l at ed

20MW

27MW

10:1 turndownfan assisted


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4 x 4 5 0 0 m 3/ h + 2 x 15 00 m 3/ h ( 1 @ 1 0 : 1 t u r n d ow n )

10:1turndown

Total

105MW


l fl ( l ) d


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HAASE lean gas flare (pilot) down to 10%methane


T l l d l f


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Telecontrol system can record values forcarbon credits

On-site-control Remote control



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Hat f ie ld Co l l i e ry 4 x Roots blower delivering

880Nm3/h (each) at -500mbarg to

-100mbarg delivery

2 x Roots blower delivering1660Nm3/h (each) at -100mbarg to

+200mbarg delivery



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The HAASE st a te o f t he a r t h i gh t em pe ra tu re f l a re in su m m ar y ;

99.9% CH4 destruction Down to 25% CH4 , or lower with propane

assistance at ignition

Turn down ratio 5:1 standard, 10:1 or greateroptional

10 year lining guarantee Exceeds German TA Luft requirements



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Thank you!Clarke Energy distributes GE Energy Jenbacher and HAASE best in class products supplying, installing and maintaining

www.clarke-energy.com

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Coal Flaring

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