Two Technical Advances in Wet Chemical Scrubbing Technology

ERG (Air Pollution Control) Ltd

Two Technical Advances in Wet Two Technical Advances in Wet Chemical Scrubbing TechnologyChemical Scrubbing Technology

Richard HansonRichard Hanson MA MEng CEng MIChemE MA MEng CEng MIChemEERG (Air Pollution Control) LtdERG (Air Pollution Control) Ltd

ERG (Air Pollution Control) Ltd www.ergapc.com

IntroductionIntroduction | Two Technical | Two Technical AdvancesAdvances

V-texV-texTMTM technology technology DevelopmentDevelopment Process DescriptionProcess Description Applications and Case studies Applications and Case studies

Zero-effluent scrubbersZero-effluent scrubbers Process Description Process Description Applications and Case StudyApplications and Case Study

SummarySummary


V-texV-texTMTM | Development| Development

Developed in UK by AEA Technology Developed in UK by AEA Technology

Used in difficult applications Used in difficult applications reliability and performancereliability and performance Eg. nuclear industryEg. nuclear industry

V-texV-texTM TM technology used in technology used in ScrubbingScrubbing StrippingStripping Distillation Distillation Mixing Mixing


V-texV-texTMTM | Development| Development

V-texV-texTMTM Scrubbing Scrubbing Since early 1990s in UK and Since early 1990s in UK and

Ireland Ireland Mid-late 1990s in USAMid-late 1990s in USA More than 400 systems installedMore than 400 systems installed

Technology is now owned by ERGTechnology is now owned by ERG

What is it…?What is it…?


V-texV-texTM TM | Process Description| Process Description

Key features Key features V-texV-texTMTM chamber chamber Tangential gas inletTangential gas inlet Opposed jet spray nozzleOpposed jet spray nozzle Intense mixingIntense mixing Central gas outletCentral gas outlet



Opposed jet self-cleaning spray Opposed jet self-cleaning spray nozzle nozzle

Fine droplet spray patternFine droplet spray pattern Induced swirl from tangential gas Induced swirl from tangential gas

flowflow Typical droplet size 100-200 Typical droplet size 100-200 μμmm Large surface area for mass Large surface area for mass

transfer transfer



Mass transfer modelsMass transfer models

Traditional packed towersTraditional packed towers Tower diameter = Tower diameter = ff (gas rate) (gas rate) Efficiency = Efficiency = ff (packed height) = (packed height) = ff (HTU) (HTU) HTU = HTU = ff (packing type, liquor rate, gas rate) (packing type, liquor rate, gas rate)

V-texV-texTMTM Chamber diameter = Chamber diameter = ff (gas rate) (gas rate) Efficiency = Efficiency = ff (liquor rate, liquor pressure) (liquor rate, liquor pressure)


V-texV-texTM TM | Implications of transfer | Implications of transfer modelmodel(1) Non-clogging(1) Non-clogging No packing to foulNo packing to foul Applications for dirty gas/liquorApplications for dirty gas/liquor Scrubbing with slurriesScrubbing with slurries Reliable performance, lower Reliable performance, lower

maintenance, guaranteed efficiencymaintenance, guaranteed efficiency


V-texV-texTM TM | Implications of transfer | Implications of transfer modelmodel(2) Significantly reduced vessel height(2) Significantly reduced vessel height High pseudo-KHigh pseudo-Kgga valuesa values Intense mixing, high turbulenceIntense mixing, high turbulence Gas residence time reduced approx x10 for same scrubbing efficiencyGas residence time reduced approx x10 for same scrubbing efficiency


V-texV-texTM TM | Implications of transfer | Implications of transfer modelmodel

ERG Packed Tower Scrubber

V-texTM

Scrubber

Example: Example: 1000 m1000 m33/hr air/hr air HCl removal efficiency HCl removal efficiency

99.5% 99.5%

7.4 m

2.2 m


V-texV-texTM TM | Case studies| Case studies

ClCl22 scrubbing scrubbing Chemical industryChemical industry Chlorine scrubbing from process Chlorine scrubbing from process

air streamair stream NaOCl by-product for saleNaOCl by-product for sale



HCl scrubbingHCl scrubbing Pharmaceutical industryPharmaceutical industry Hastelloy C276 and ECTFE/PTFEHastelloy C276 and ECTFE/PTFE Pressure and explosion rating Pressure and explosion rating

certifiedcertified >99.5% HCl removal efficiency, >99.5% HCl removal efficiency,

batch scrubbingbatch scrubbing


Reactive gas scrubbing + particulate Reactive gas scrubbing + particulate removalremoval Optical Fibre ManufacturerOptical Fibre Manufacturer Removal of HCl and SiORemoval of HCl and SiO22 Scrub liquor contained up to 5% weight Scrub liquor contained up to 5% weight

SiOSiO22 with no blockage with no blockage Constant back pressure improved Constant back pressure improved

optical fibre qualityoptical fibre quality



V-texV-texTM TM | Case studies| Case studies Multi-component contaminants Multi-component contaminants

Tobacco ManufacturerTobacco Manufacturer Steam quench/sub-cooling with NHSteam quench/sub-cooling with NH33, VOC and dust scrubbing , VOC and dust scrubbing Scrub liquor contained entrained dust – unsuitable for packed towerScrub liquor contained entrained dust – unsuitable for packed tower

SOSO22 scrubbing ex-incinerator scrubbing ex-incinerator 12,000Am12,000Am33/hr with 5,000mg/m/hr with 5,000mg/m33 SO SO22 Lime slurry scrubbing Lime slurry scrubbing >99.8% removal SO>99.8% removal SO2 2


Zero-EffluentZero-Effluent | Process | Process Description Description Vacuum evaporation: application to scrubbingVacuum evaporation: application to scrubbing

Established technologyEstablished technology Process application innovationProcess application innovation System integration – optimisation of capital and operating costsSystem integration – optimisation of capital and operating costs Minimises water usage and effluent disposalMinimises water usage and effluent disposal

Simplified flowsheetSimplified flowsheet Evaporator/condenser circuit, heat pump circuit, effluent circuitEvaporator/condenser circuit, heat pump circuit, effluent circuit


Zero-EffluentZero-Effluent | Process | Process DescriptionDescription

Schematic courtesy of H2O GmbH


Zero-EffluentZero-Effluent | Process | Process DescriptionDescription Typical Scrubber blowdown 500 litre/hr Typical Scrubber blowdown 500 litre/hr < 40 litre/hr concentrated < 40 litre/hr concentrated

sludge waste + recovery of > 460 litre/hr process water to systemsludge waste + recovery of > 460 litre/hr process water to system Operation at 5kPa and 40Operation at 5kPa and 40ooC C Typically 0.15kW per litre water evaporatedTypically 0.15kW per litre water evaporated


Zero-EffluentZero-Effluent | Case study | Case study

Aerospace industryAerospace industry Chromic acid scrubberChromic acid scrubber 200 litre/hr treatment rate200 litre/hr treatment rate 200 g/litre CrO200 g/litre CrO33 commodity recovery commodity recovery Return on investment = 9 monthsReturn on investment = 9 months


Zero-EffluentZero-Effluent | Applications | Applications

High water/effluent costs and low energy costsHigh water/effluent costs and low energy costs Feedstock, product and by-product recoveryFeedstock, product and by-product recovery Minimised loading for RO and ion-exchange treatment plantsMinimised loading for RO and ion-exchange treatment plants


SummarySummary

Innovations in Scrubbing technologyInnovations in Scrubbing technology

V-texV-texTMTM Solid-laden gas/liquor applicationsSolid-laden gas/liquor applications Space limitationsSpace limitations

Zero-effluentZero-effluent Feedstock/product recoveryFeedstock/product recovery Utility optimisation Utility optimisation

Documents

Two Technical Advances in Wet Chemical Scrubbing Technology