Air Pollution Control for Press and Dryers - CORMA · Business Confidential Air Pollution Control...

Business Confidential

Air Pollution Control for Press and Dryers in

Wood Panel Industry

© TurboSonic Inc. 2012 Business Confidential 2

Emissions in Wood Panel Industry

� Rotary Dryers – OSB, PB

� Flash tube dryers – MDF

� Veneer dryers

� Continuous Press

� Multiple opening press


Rotary Dryer Emissions

� From direct fired energy system

� Ash – metallic oxides, sand – combination of large and fine

particulate

� Unburned carbon – char, soot – submicrom particles

� Sublimated fume from molten metals – submicron

particulate

� From Dryer

� mechanically generated dust or fiber – large particles

� Volatile Organic Compounds - Pitch and tar from heated

wood that condenses at stack generating “blue haze” –

submicron aerosols

� Volatile Organic compounds – non condensable at stack

temperature


Flash Tube Dryer Emissions

� If from direct fired energy system

� Ash – metallic oxides, sand – relatively

small particulate

� Unburned carbon – char – large particles,

soot – submicron particles

� Sublimated fume from molten metals –

submicrom particles

� From Dryer

� Mechanically generated dust or fiber

� Little or no VOCs – depends on

temperature


Veneer Dryer Emissions

� From Dryer

� Very little mechanically generated dust or

fiber – large particles

� Volatile Organic Compounds - Pitch and tar

from heated wood that condenses at stack

generating “blue haze” – submicron aerosol

or mist


Press Emissions

� Particle Board, OSB press

� Little mechanically generated dust or fiber –

large particulate

� Volatile Organic Compounds - Pitch and tar

from heated wood that condenses at

exhaust – submicron mist, aerosols, may

form “blue haze”

� VOC – formaldehyde from formaldehyde

based resins


Air Pollution Control Equipment


Equipment

� Wet Scrubbers – for particulate control – large particulate

� dust

� Wet ESP – For fine particulate control

� Submicron particulate – sublimate of metal oxides

� Blue haze (aerosol tar mist)

� Chemical Oxidation – for water soluble VOC

� Biofilter, Bioscrubber – for water soluble VOC

� RTO – Regenerative Thermal Oxidizer – total VOC


Venturi Scrubber

� Low maintenance

� Vertical down flow with wash ring

� No nozzles to plug

� Adjustable throat

� Particulate matter removal for 1-3 micron and larger particles

� Acid gas absorption

� Some water soluble VOC removal, but recirculating water system quickly becomes saturated

Process Gas

Clean Gas

Recycle Liquid


� Similar function to venturi scrubber but less efficient

� Lower cost

� Lower pressure drop

� Has hydraulic nozzles

� No internals to plug

Cyclonic Scrubber


© Business Confidential 11

Low Energy Scrubber

High Energy Scrubber

Droplet Size Relation in Wet Scrubbing


Wet Scrubber

� Benefits

� Low maintenance

� Low cost of equipment

� Particulate removal

� Some VOC removal

� Sometimes used as preliminary scrubbers upstream of other equipment

� Disadvantages

� Only removes larger particulate matter

� Water treatment and disposal required

� Limited to water soluble VOC removal

� scrubbing solution quickly saturates with absorbed VOC


Venturi Scrubber - MDF Dryer

� TurboVenturi scrubber to reduce particulate carryover from MDF dryers upstream of a RTO


Cyclonic Scrubber/WESP - OSB Dryer

� Cyclonic scrubber

� Retrofit upstream of competitor’s WESP system to improve WESP performance


Rotary Dryer for Wood Pellet Mill

Venturi Scrubber


Cyclonic Scrubber - OSB Press

� Retrofit of Cyclonic Scrubber upstream of biofilter – to prevent wood particles from carryover into biofilter media


© Business Confidential 17

� Cyclonic Scrubber

� Continuous OSB Press

� Particulate and condensable scrubbing

before Biofilter

� Duct irrigation system over press enclosure

Cyclonic Scrubber - OSB Press


Venturi Scrubber - MDF Press and Dryer

� Venturi Scrubber

upstream of CGT –

chemical oxidizer

� For particulate

removal


Quench Duct Sprays

Wet Electrostatic Precipitator (WESP)


WET ESP

� Used for final particulate removal device in most countries (except USA)

� Removes submicron particulate to emission levels typically less than 50 mg/Nm3 (less than 25 mg/nm3 to provide clear stack

� Removes aerosol tar mist from rotary dryers and sublimate metal oxides from direct fired energy systems

� Operates on water saturated gas steam so usually following a pre- scrubbing stage


How it Works

� Charging: Particles and droplets are given strong negative charge

by ionizing corona produced by

high-voltage electrodes

� Collecting: The electric field

causes charged particles and

droplets to migrate to the grounded walls of the tubes where

they accumulate

� Removing: The falling water film inside the tubes removes the collected material to a discharge drain


Gas InletIntermittent Flushing Header

High Voltage Support Insulators

High Voltage Insulator Compartment

Patented Discharge Hood Design

Gas Outlet

Discharge Drain

Gas Distribution Perforated Plates

Collecting Electrodes Hex Tubes

High Voltage Electrode Support Frame


� 2006 – 2007 Louisiana - state of the art OSB mill – Southern Yellow Pine wood species

� 917.450 m3/h total flow on 3 Turbo-Venturi and SonicKleen™WESP systems

� Reliability – Reduced Maintenance – Superior Performance

� SonicKleen™ WESP Voltages operate at 75 - 80 KV.

� Falling film irrigation & proper flushing header design yield spotless clean internals despite handling pine pitch and tar.

Venturi Scrubber/WESP – OSB dryer


WESP - OSB Rotary Dryer

� 3 rotary dryers: single and triple pass

� SonicKleen™ WESP system with a quench pre-scrubber

� Replacement of existing horizontal plate WESP


Venturi Scrubber/WESP - OSB Dryer

� 3 single pass rotary dryers

� SonicKleen™ WESP system

� TurboVenturi scrubber

� Full water treatment system


Venturi Scrubber/WESP - Particleboard Dryer

� Add on to existing venturi scrubber for Blue Haze and tar mist removal

� Outlet emission 25 mg/Nm3

� Blue Haze eliminated

VOC removal equipment


Catalytic Gas Treatment

� Formaldehyde & methanol removal >90%

� Uses peroxide and 2 catalysts

� Ideal for low VOC concentrations found in wood products

� Less than 5” ∆P


Process Gas

Particulate & Condensible Pre-treatment

CGT

Chemical Reaction & Liquid Re-circulation

• Wood Products

• Dryer

• Press

• Other Industries

Filtration

Circulation

H2O2

Catalyst

pH Control

H2O Makeup

Blowdown

Clean Gas

to Atmosphere


Biofilter/Bioscrubber

� VOC Control for press emissions

� Needs upstream particulate removal device


RTO – Regenerative Thermal Oxidizer

� For press or Dryer VOC control

� 90-95% removal efficiency of all VOCs

� 95-96% thermal efficiency

� Reduction of CO


RTO – Regenerative Thermal Oxidizer

� Heats entire has stream to approx 1500 ºF (815ºC) to incinerate all hydrocarbons

� Utilizes heat value of VOCs plus natural gas to maintain temperature

� Recovers heat by using alternating ceramic beds to sink and release heat from gas stream


Catalytic Gas Treatment Biofiltration Thermal Oxidation

Avoids the production of combustion-related GHGs

Avoids the production of combustion-related GHGs

Creates large volumes of GHGs (ex. 34,000 tpy for large OSB mill)

No non-renewable fuel required No fuel useHigh fuel use and resultant cost of operation

Low pressure drop (energy use) Moderate pressure drop High pressure drop

Small footprint Large footprint Medium footprint

No collateral odor generation Reported to generate collateral odors No collateral odor generation

Instant on/off; no standby costsStandby costs - fan operation, nutrient addition & cont’d maintenance

High standby costs

No sensitivity to temperatureSensitivity to T>120°F & cool temperatures

Negligible maintenance costMaintenance costs – nozzle irrigation & humidification, media deposition

High maintenance requirement

Low chemical cost; consumption proportional to concentration of oxidizable contaminants

Thermal destruction of a wide range of combustible contaminants including VOCs

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VOC Control Choices


Thank You

TurboSonic Inc.

www.turbosonic.com

[email protected]

Head Office:

Waterloo, ON, CanadaTel: 519.885.5513Fax: 519.885.6992

US Office:

Bollate (MI), ItalyTel: 39 02 38305384Fax: 39 02 33301943

European Office:

Raleigh, NC, USATel: 919.844.0411 Fax: 919.846.0055

Air Pollution Control for Press and Dryers - CORMA · Business Confidential Air Pollution Control...

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