solvent emissions from the organic coating process jim rowbotham pexa ltd. © pexa 2009
TRANSCRIPT
Solvent Emissions From the Organic Coating Process
Jim RowbothamPexa Ltd.
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Nearly there© Pexa 2009
What’s the Problem?
Climate Change
Carbon Footprint
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Leadership
“a step that will also reduce our carbonemissions 80% by 2050”.
“commits Britain to cut carbon emission by 34 per cent by 2020”
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Contribution
Paints based on organic solvents
Carbon derived from fossil sources
Used as a carrier in paints, evaporates and adds to the environmental carbon compound concentration
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Regulation
This paper focuses on The EU Solvent Emission Directive 13/1999.
Embodied in the UK for Aerospace as guidance notes.
- PG6-40 Painting- PG6-45 Surface Cleaning
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Thresholds Defined for Coating by Size of Activity
0 - 5000 Kg of solvent used - Not controlled
5 – 15,000 Kg – “small process”
15 – 200,000 Kg – “large process”
>200,000 Kg - special process(IPPC)
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Objectives of Presentation
Simplify the directive Focus on most important items Desktop methods for estimating current emissions Propose simple tools for evaluating compliance Some ideas for improvement Sound basis for regulator
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Painting Process
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Painting Activity – How to Comply?
“Non toxic” (non CMR R40 etc) solvents
1) Reduce to < 5000Kg 2) Control of emission concentrations 3) Mass reduction scheme4) (BAT)
CMR R40 solvents (essentially not used)
1) Control of emission concentrations2) Nothing
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Painting Process – 2 Emission Control
VOC’s (as carbon) must be <50 mg/cubic metre of air. For R40s etc is <20 mg/cubic metre (as compound)
Particulates must be <50 mg/cubic metre of air Can be continuously monitored, or periodically monitored,
must be retested when process changed Can be reduced by rate management, incineration,
cryogenics, carbon/polymer absorption, biodegradation. NOT by Dilution.
Time weighted average, batch vs continuous process Previous rules will not be relaxed
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Painting Process - 3 Mass Reduction Scheme
Annual solvent emission to be less than target emission (Te)
Te = M x F1 x (FEV + F2) 100
M = mass of solids/year F1 = multiplication factor (sector related) FEV = fugitive emission value (solvent use related) F2 = 15 or 5 (solvent use related)
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Worked Back to 100 Tonnes (%)
FactorSolvent Usage (TPA) 5 - 15 >15Tonnes Solids/ann. [M] 100 100Multiplication Factor [F1] 2.33 2.33Fugitive Emission Value [FEV] 25 20Solvent Use Factor [F2] 15 5Target Emission [Te] (TPA) 93.2 58.3equivalent av. VOC content*% (less water) 48.2 36.8g/l (less water) 531 405
Aerospace Sector
Input Factors
Output results
* using SG 1.1
Te = M x F1 x (FEV + F2) 100
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Conclusion Painting
Process Size Max average VOC into process
5,000 – 15,000 Kg 531 g/l
>15,000 Kg 405 g/l
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Whole Aircraft Painting
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Whole Aircraft Painting 3 – Mass Reduction Using High
Solids paint System
Product VOC g/lVolume required
Total VOC Kg
Total (average) (688) 385 265
Total (average) (447) 245 110Paint Stripping Excluded
Boeing 737 Estimated typical VOC consumptionsConventional
High Solids
Compare to Max 531 g/l or 405 g/l
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Whole Aircraft Painting 2 – Emission Concentration
Note – Regulation is weighted over 30 minutes
Conventional 3,600,000 265,000 74 mg/M3 53 mg/M3High Solids 3,600,000 111,000 31 mg/M3 22 mg/M3
Potential average VOC emission concentration during total paint process
Model for B737 in hangar 50,000 M3Processing time 6 days, average number of air changes 0.5 per hour
Total air emitted M3
Total VOC emission g
Average emission
concentration
Average emission concentration Carbon
Paint system
* = taking compound as 1.4 x total mass of Carbon
Limit 50mg/M3 as carbon
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Whole Aircraft Painting 1 – Thresholds
VOC threshold
Average VOC
Conventional 688 g/l 18 56
High Solids 447 g/l 45 136
Does not include paint removers
Number of B737 aircraft painted to achieve VOC threshold
System Choice 5000 Kg 15000 Kg
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Whole Aircraft Painting
4 – BAT
• Article 5 (3) (b) allows that processes which cannot be contained e.g. aircraft painting, may be exempted from the annex II A controls. Providing that BAT can be demonstrated.
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Surface Cleaning Process
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Surface Cleaning – Permit Required
Group Description
1. either, 1 tonne or more of cleaning solvents that are labelled (classified) with any of the R phrases R45, 46, 49, 60 or 61 (the product label and Safety Data Sheet give this information)
2. or, 1 tonne or more of halogenated cleaning solvents that are labelled (classified) with the R phrase R40 (the product label and Safety Data Sheet give this information)
3. or, 2 tonnes or more of any other organic cleaning solvent
BCF Guidance Note E018© Pexa 2009
Surface Cleaning – Emission Limits
BCF Guidance Note E018
group: 12 month usage Stack (e.g. exhaust flue) emissions
Fugitive (all other)emissions
Group 1: 1-5 tonnes
2 mg cleaning solvent/m3 (20 mg if mass flow below 10g/hour)
15% of solvent used
Group 1: more than 5 tonnes
2 mg cleaning solvent /m3 (20 mg if mass flow below 10g/hour)
10% of solvent used
Group 2: 1-5 tonnes
20 mg cleaning solvent/m3 (mass flow above 100g/hr)
15% of solvent used
Group 2: more than 5 tonnes
20 mg cleaning solvent/m3 (mass flow above 100g/hr)
10% of solvent used
Group 3: 2-10 tonnes
75 mg carbon/m3 20% of solvent used
Group 3: more than 10 tonnes
75 mg carbon/m3 15% of solvent used
Note: the Group 3 limits do not apply if the average organic solvent content of cleaning solvents is below 30%
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Practical Reductions
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Structural Paint System VOCs
HS vs Water BasedWith an average 70% primer and 30% topcoat
HS Primer 37092 350 g/lHS Topcoat 67348 420 g/l 371 g/l
Aerowave Primer 2001 250 g/lAerowave Finish 3003 250 g/l
250 g/l
Conclusion – Mass reduction is well within limits and the best way to comply – water based = HEADROOM
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Laminar Flow Spray Technology
Dux British Patented Design
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Laminar Flow Spray Technology
Particle Image Velocimetry Images
Particle Density is greatest where image is darkest
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Laminar Flow Spray Technology
Application at Major UK Based Aero-Engine MRO
Cascade Vents
Paint consumption reduced from 225ml to 125ml = 44%
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Impregnated Cleaning Wipes vs. Solvent Washing
- In European Aerostructures manufacture we have reduced solvent consumption by 75%-95% changing from traditional fluid solvent (MEK) and cotton rags to Satwipes Diestone DLS.
- Presaturated wipes with controlled surface area and controlled measure of solvent applied to each wipe.
- Self closing Lids
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Aqueous Cleaning vs Vapour Degreasing
Moving from vapour degreasing with Trike (and other solvents) to aqueous washing using a new generation of approved aqueous cleaning products such as Sococlean A3433, gives a 100% reduction in VOC emission.
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Recommendations
Understand the requirements. Use the desktop exercises to determine thresholds
and actual contributions. Implement proven, practical VOC reduction methods
and recalculate contributions. Get ahead of the regulator.
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