Preventing VOC’s from destroying your reputation and ... › wp-content › uploads › 2019 › 07 › 04-A… · Odour Control Anaerobic Digestion Thermoplastic Tanks Waste Water

Odour Control Anaerobic Digestion Waste WaterThermoplastic Tanks

Preventing VOC’s from destroying your reputation and

bottom lineColin Froud

UK AD & World Biogas Expo July 3rd 2019


Odour Abatement Portfolio includes• Biofilters

• Bioscrubbers

• Wet Chemical Scrubbers

• Dry Chemical (Carbon)

• Catalytic Iron Filters (CIF)

• Terminodour™ (Ionisation)

• Phot-OX (Photo-Oxidation)

• Biogas Desulphurisation

• Odour modelling

• Odour surveys/VOC screening

• Online odour/VOC monitoring

• Troubleshooting

• Maintenance/Service


Volatile Organic Compounds (VOC’s)• The term VOC’s covers a wide range of naturally occurring and man made

chemicals all of which have the common denominator of a low boiling point.

• VOC’s are present in food packaging materials (an example of man made VOC’s) but many are naturally occurring, such as terpenes, that can be found in plants and foods and other common substrates for AD plants.

• There are a very large number of different VOC’s, some harmful to health and some harmless.

• Some VOC’s are completely odourless whilst others have a nauseous hedonic tone and a very low detectable odour threshold.

• VOC’s can be detected, speciated and measured using GCMS.


The problem with VOC’s• The vast majority of odour issues on an AD plant are as a result of VOC’s,

either fugitive emissions or just passing through the existing odour abatement plant untreated.

• Water soluble VOC’s can be removed in a variety of ways relatively easily, but non-soluble VOC’s present considerable issues.

• Difficult to predict the likely VOC cocktail until the plant is operational and even then GCMS will only give a snap shot in time.

• Without a detailed speciation and quantitative analysis selecting the correct abatement solution is not straight forward.

• Base carbon is the normal solution and works effectively but operational costs tend to vary between high and stratospheric.


Potential OptionsExisting Plants:• Failing system or exorbitant

operational costs?• Take a full VOC screen not just a

top 40 GCMS – to understand the problem

• Select a technology that addresses your issues and is best suited to the known VOC cocktail.

• Can it be retrofitted and integrated into the existing plant ?

New Plants:• Dispersion model and determine

abatement efficiency required.• Select a technology that has a

proven track record on similar applications and can meet the emission challenge.

• Consider the possibility for additional mitigation measures, at the design stage, if the system does not achieve required emission performance or is cost prohibitive to operate.


Base CarbonThe Positives

• Very effective on most VOC’s (whether they smell or not!)

• Base carbon is cheaper than impregnated carbon and more effective

• Regenerated carbons also available

• Pelletised carbon better than granular

• Good catch all system particularly for new plants where VOC speciation and load is uncertain

The Negatives

• Variable weight by Volume take up rates depending on VOC types = Short media life

• High to very high operational costs


Chilling and Drying prior to Carbon• The adsorption capacity of carbon can

be increased by:-

• Reducing relative humidity (optimally 50%) using a gas dryer.

• Reducing temperature of incoming gas (<20°C ideally) using a gas chiller.

• Solution suits VOC/Siloxane removal from biogas applications with low flows – but not desulphurisation.

• Not cost effective on large volumetric flows.


Photo-Oxidation• Utilises UV- C light to create ozone

a powerful oxidant and a catalytic carbon to convert O3 back to O2.

• Ideal retrofit for reducing incoming load to an existing carbon filter and reduce OPEX by up to 90%.

• Can also be used as a sole system depending on VOC cocktail and emission requirements.

• Suitable for both small and large applications.


Ionisation

• Positive pressure ionisation system oxidise odours within the building.

• Normally used without any further treatment stages.

• Can be used to pre-treat air prior to carbon filter and partially regenerate carbon in situ.

• Suitable for most VOC’s but not all.

• Ideal for large building volumes.

Food waste reception hall


Additional options

• Biofilters – work well on water soluble VOC’s but many non soluble VOC’s can pass through untreated.

• Regenerative Thermal Oxidisers (RTO’s) - very effective solution but can have high capital and operational costs particularly if siloxane is present in the gas stream. Obviously don’t use on Biogas.


Knowledge is Power

• Understanding the problem is critical to success.

• A full VOC screen is infinitely preferable to a top 40 GCMS.

• A recent VOC screen from an odour source on an AD plant identified >100 species of VOC’s.

• If the problem is understood a solution can be found.


Monitor

• Its now possible to monitor VOC’s, siloxanes and other odours/ compounds in waste air and biogas streams online and in real time.

Select compund to be shown as

graph

Click on point on graph to

show details in text box.

Click to addwritten note

to measuremen

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change timerange to show

on graph

Total siloxanes beforefiltering

Total siloxanes after

filtering


Qualvista Biogas Monitor - Summary• Continuous process monitoring.

• Multiple measuring points for siloxanes, total VOC, CH, CO2, H2S, and O2.

• Robust, accurate and reliable.

• Includes a temperature-stabilized cabinet for indoor and outdoor use.

• Fully automated measurements.

• Automatic system calibration.

• Patented measuring system based on the NDIR (Nondispersive Infrared) method.

• Sensitive system with low detection limits.

• New measurement data available every 10 to 40 minutes.

• Online reporting tool with customisable view of the biogas measurement information.

• Information can be reported in any required unit(s), e.g. mg/m3, ppm or ppb.

• Online reporting information can be accessed anywhere with standard PC and mobile devices.

• The data can also be downloaded in CSV format to be used in e.g. spreadsheet or process information and control system.


Carbon - an unvirtuous circle?


Summary

• Understand the VOC challenge

• Consider other critical factors (Space, services, regulatory, Capex & OPEX considerations)

• Short list the potential solutions

• Weigh up the merits of each option

• Select solution


With thanks to

• Dr Joerg Stockinger – Siloxa AG

• Qualvista

• Saria Group

• Likusta


Thank you for your attention

www.csogroup.co.uk

[email protected]

+44 1732 700011

Chequers Barn, Chequers Hill, Bough Beech, Kent TN8 7PD, UK

http://www.csogroup.co.uk/

mailto:[email protected]

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Preventing VOC’s from destroying your reputation and ... › wp-content › uploads › 2019 › 07 › 04-A… · Odour Control Anaerobic Digestion Thermoplastic Tanks Waste Water