Challenges & Opportunities of pre-treatment for AD Plants Mike - - PowerPoint PPT Presentation

Challenges & Opportunities

• f pre-treatment for AD Plants

Mike Bullard Managing Director, UTS Biogas Ltd

Contents

• Introduction to UTS/Anaergia
• “pre-treatment” agricultural systems

In contrast to

• “pre-treatment” SSO waste systems
• Conclusions

Biogas plant May Farm, Ely, Cambs Biogas plant Dagenham, London

Case-studies in the presentation

Manure/grass Biogas plant, Yorkshire

About Anaergia/ UTS Biogas

4

• Global technology leader in the recovery of value from organic waste

streams

• Proven portfolio of proprietary technological solutions around

anaerobic digestion core

• Flexible project delivery options, including process turnkey supply,

DBOO (including financing)

• Over 20 years of design and operating experience
• Core technologies used in over 1,600 digester plants with over 355MW
• f capacity from biogas
• UTS Biogas Ltd is the sole delivery agent for all Anaergia products in

the UK and Ireland (UK based technical and project management)

• In the UK: 9 plants operational, 4 larger facilities in-build.
• Turnkey design construct commission services; pre-treatment, biogas

production and utilisation; digestate management. CHP and BtG. EPC

• r technology supply.

Anaergia’s Technology Platform Built On In-house Manufacturing, R&D and Exclusive Partnerships

Organics Pre-treatment Core Technology Post Treatment

Organics Extrusion DB Technologies Recyclable Recovery DB Technologies Solids Separation Anaergia / UTS Hydraulic Mixing Anaergia / UTS Service Box Anaergia / UTS Materials Handling Anaergia / UTS Residuals Drying Therma-Flite (Exclusive Partner) Membranes Fibracast (Subsidiary) Gasification KIV (Exclusive Partner) Biogas Upgrading Greenlane (Partner) Anaerobic Digesters Anaergia / UTS

Pre-treatment; what’s the problem?

Key issues

• Heterogeneity – good pre-treatment produces

homogeneity in the feed material

• Contamination – good pre-treatment removes

contaminants effectively

• Accessing the organics – good pre-treatment

capture a high proportion of organics for AD

• Recyclates recovery – good-pre-treatment

enhances recyclate value

• Keeping the organics clean – boosts gas yields
• Achieving PAS110 – all of the above needed to

achieve PAS110 and thus meet end of waste criteria

May Farm

Primary Fermenters Secondary Fermenters Digestate Storage Tank CHP Area Pasteurisers & Separator

Incoming Solid Feed Weighbridg e Conditioning Feed hopper Output-Fibre Separated Solid Digestate Separator Digestate Storage Tank Buffer Tank Batch pasteurisatio n Maceration Output Liquid digestate Primary Fermenter Secondary Fermenter CHP Output Electricity Output Heat Desulphurisatio n Conditioning

May Farm process flow

Grass/ manure Biogas plant

Incoming Solid Weighbridge Conditioning Feed hopper Output-Fibre Separated Solid Digestate Separator Digestate Storage Tank Output Liquid digestate Fermenter CHP Output Electricity Output Heat Desulphurisation Incoming Liquid Receptio n tank Stone Trap

Grass/ manure Biogas plant

Static pre-treatment solution

Mobile pre-treatment solution

Dagenham

Composting building

Incoming Waste Weighbridg e Reception building Biowaste Preparation equipment Output-Fibre Hall Separated Solid Digestate Separator Digestate Storage Tank Buffer Tank Batch pasteurisatio n Maceration Output Liquid digestate Receptio n tank Primary Fermenter Secondary Fermenter CHP Output Electricity Output Heat Desulphurisatio n

SSO treatment

• Key process design parameters -

Process design parameter Unit Value Solid concentration organic fraction % of wet 25 – 35 Volatile solids organic fraction % of dry 85 – 95 Solid concentration input digester % of wet 25 - 30 Solid concentration output digester % of wet 10 - 15 Organic loading digester kg VS/(m3*d) 6.5 – 8 Hydraulic retention time (HRT) digester Days 40-60 Specific biogas production Nm3/t VS 680 – 750 Specific biogas production Nm3/t wet 130 – 150 Contamination levels % (w/w) 3-25%

MSW / SSO treatment

• Low contamination -

SSO upfront processing system: Hammer Mill

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• Hammers disintegrate contaminants

(glass, plastic)

• Organic fraction for AD is

‘contaminted‘ with glass, plastic

• The more the SSO contamination level

as more water is required to process the SSO

• Challenged by contamination > 10% -

Grit and plastic separation systems are required if highly contaminated SSO is treated

• More process water = greater digester

size = greater costs

• Biobags are an issue
• Not suitable for processing biowaste

with high green waste content

• Heavy parasitic power consumption
• Reject stream needs to be pressed to

reduce moisture content

• Difficulty dealing with heterogenous

wastes

Other SSO: alternative upfront processing systems

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Impacts of poor pre-treatment

• Poor removal of contraries leading to build up of silts,

sediments, plastics floating layers.

• Loss of digester capacity – silting and additional water

addition

• Potential toxicity
• Failure to achieve PAS110 (plastics)
• Extra costs of post-process digestate screening
• Additional mixing causing higher electricity consumption
• Greater organics carry-over in residual waste stream; loss of

biogas yield and potential recycling target issues

• Blockages
• Additional pump wear and tear – increased opex
• Heterogeneity – loss of gas yield

Conclusions

• Hammer-mill and turbo-separator systems

available in the market place:

– Require significant amounts of process water and therefore have cost impacts on remainder of plant design – Do not cope with high levels of impurities – Do not recover high proportions of organics – Leave a dirty residual stream – Have high opex costs – Do not give a clean organics stream

• The waste industry needs something better!

Thank you

Mike Bullard Mike.bullard@uts-biogas.com 0044 1480 477608