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Black Powder Removal from Transmission Pipelines Diagnostic & Solutions

Lindsay McRae – Pall Australia

Kaustubh P Chitale – Pall India

© Pall Corporation, 2003© Pall India Pvt Limited 20102

• Generic word designating typically various forms of iron sulfide, iron oxide, iron carbonate

• Contaminants like sand, pipeline debris, liquid HC… can also be present

• Global phenomenon, potentially any kind of transmission lines (gas, condensate, LPG…)

• Formation due to internal reactions with steel:

• Chemical: internal corrosion in presence of water, acidic compounds (CO2 / H2S), oxygen

• Biological

• Presence of water inside pipelines due to condensation of water vapor, or due to process upsets

What is ‘Black Powder’?

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• Erosion of control valves

• Erosion of gas meters

• Erosion of pipelines

• Deposits inside compressors

• Fouling of instrumentation

• Operating issues at end users

• Complaints from end users

• etc…

Consequences of presence of Black Powder

Erosion Damage on 12-Inch Control Valve Body (top) and Trim cage (bottom)(By Courtesy of a Middle East oil company)

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• Possible approaches to overcome Black Powder issues:

• Elimination of root causes (moisture…)

• Internal pipeline coating

• Separation technologies

Solutions for removal of Black Powder

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• Various solid/gas or solid/liquid separation technologies available on the market

• Typically usage of filters or cyclone separators

• But removing Black Powder efficiently is difficult !

• Reality:

• Black Powder particles are very fine (typically <10-15µm)

• Nominal rated filters are not effective enough

• Cyclonic separators have limited removal performances, and efficiency drops with changes in operating conditions

Solutions for removal of Black Powder

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• Black Powder particles are very fine (typically <10-15µm)

Solutions for removal of Black Powder

5-10µm75%

10-15µm18%

(results from Pall site survey on condensate)

(results from Pall site survey on gas)

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• Nominal rated filters are not effective enough

• In practice, particles larger than the pores pass through nominal filters

• Absolute rated filters are recommended for a reliable and reproducible quality

Solutions for removal of Black Powder

Source : “Principles of Filtration - Scientific & Technical Report WER 5300, Pall Corporation”

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• Selection of suitable solution requires a good understanding of the problem

• Characteristics of Black Powder

• Total Suspended Solids content (TSS)

• Particle Size Distribution (PSD)

• Root causes

• Nature (chemical composition)

• Scrutiny of process data (high dew point,…) or pipeline history

• Site survey capabilities and technical expertise can be proposed if lack of data

Diagnostic of Black Powder issues

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• Site survey capabilities:

Isokinetic sampling using portable membrane disc holder and isokinetic probe

collection of solid contamination

Diagnostic of Black Powder issues

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• Site survey capabilities:

Laboratory means to exploit field samples

• Optical microscopy

• Scanning Electron Microscopy

• X-ray analysis

Diagnostic of Black Powder issues

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• In addition to experience, results of site survey may be useful for:

• selection of suitable locations for implementation, technologies and sizing• better understanding of root causes of particles

Diagnostic of Black Powder issues

5-10µm75%

10-15µm18%

© Pall Corporation, 2003© Pall India Pvt Limited 201012

• Middle East plant receives natural gas from network

• Gas used as feedstock, requires compression stage, and as fuel gas

• 167000 Nm3/h, 40 barg, 45 degC

• Compressor and turbines protected by filter equipped with non-Pall nominal glass fiber pleated cartridges

• Vessel diameter 800mm, with 27 off filter elements

• Problems:

• Filter elements replaced every 1-2 days to 2 weeks

• Filter not able to handle design flowrate as clean DP almost max allowable

• Heavy deposits on compressor

Case Study

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• Replacement of filter elements lead to very heavy maintenance

• Due to pyrophoric property of this Black Powder, filter vessel was filled with water, sludge drained from vessel and disposed of in drums

Case Study

Non-Pall filter elements Dry black sludge - Stored in drums

© Pall Corporation, 2003© Pall India Pvt Limited 201014

• Pall proposal: replacement of existing nominally rated filters

• High dirt removal capacity, absolute rated, depth filter media technology (Pall ‘Coreless’)

• Pall supply:• 2 filters (1 duty / 1 stand-by), ID 1280mm, equipped with 30 off Pall

‘Coreless’ cartridges each for Black Powder removal

• 2 liquid/gas coalescers (customer request), ID 950mm, equipped with 12 off Seprasol™ Plus cartridges each, for liquid removal

• Plant also purchased cyclones as pre-treatment stage, to implement upstream of filters

Case Study

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Case Study

Pall ‘Coreless’ filters

6’’

40’’

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• Plant commissioned Pall Filters and Coalescers without the upstream cyclone

• To date after 15 months of operation, Cyclone not been installed yet

• Since start-up Pall Filter has been operating at low DP (now ~400 mbar), and no change-out of cartridges since then

• All downstream equipment are fully protected, plant fully satisfied

Case Study

© Pall Corporation, 2003© Pall India Pvt Limited 201017

Upstream Pall Coreless

filter

DownstreamPall Coreless

filter

• After 6 months operation, client requested Pall to perform performance test

• On-line measurements carried out upstream & downstream Filter

Case Study

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• Black Powder particles are very fine

• Black Powder is difficult to remove efficiently

• Fine separation technologies are required to protect downstream equipment reliably

• Site survey capabilities are useful to understand the situation and to address the problem correctly

Conclusion

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Copyright 2008

Pall Corporation, , and all Pall product names included in this presentation are trademarks of Pall Corporation.

® indicates a Pall trademark registered in the USA.

Filtration. Separation. Solution SM is a service mark of Pall Corporation.

Thank you for your attentionAny questions ?

How to contact Pall : www.pall.com