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The following table outlines the Process, Advantage and Limitation of various Air Pollution Control Systems. Most are conventional methods commonly used.
Examples of new Pacific Rim GREEN BACT technology are highlighted in green.
ABATEMENT PROCESS CHARACTERISTICS
| PROCESS |
ADVANTAGE |
LIMITATION |
| COUNTER CURRENT PACKED BED SCRUBBERS |
IDEAL FOR REMOVAL OF WATER SOLUBLE COMPOUNDS LIKE SULFIDES AND ACID FUMES
MOST EFFECTIVE PACKED SCRUBBER DESIGN
|
PACKING CLOGS DUE TO PARTICULATE AND PRECIPITATION |
FINE MIST SCRUBBERS |
IDEAL FOR REMOVAL OF WATER SOLUBLE COMPOUNDS LIKE SULFIDES AND ACID FUMES
NO PACKING TO CLOG - IDEAL IN AIR WITH HIGH PARTICULATE
USEFUL IN PARTICULATE REMOVAL
|
REQUIRES COMPRESSED AIR TO CREATE SMALL WATER DROPLETS |
BIOSCRUBBER / BIOFILTER WITH FINE MIST PRE-TREATMENT AND AEROBIC DIGESTER |
TYPICALLY USED FOR TREATMENT OF FOUL AIR WITH WATER SOLUBLE VOC'S AND HIGH PARTICULATE LOADING
RECYCLES ITS OWN BIOMASS REDUCES OPERATING COST
NO NEED TO TREAT LEACHATE
ALL THREE PROCESSES WORK TOGETHER SYMBIOTICALLY IN A WAY THAT REDUCES OPERATING COST, INCREASES EFFICIENCY AND REDUCES OVERALL EQUIPMENT COST
REDUCES OPERATING COST
NO NEED TO TREAT LEACHAT
|
HIGHER EQUIPMENT COST THAN CONVENTIONAL BIOFILTER
(This is offset tenfold by lower future operating costs.)
|
| CO-CURRENT PACKED BED SCRUBBERS |
USED FOR REMOVAL OF WATER SOLUBLE COMPOUNDS LIKE SULFIDES AND ACID FUMES
INTERMEDIATE STAGE BETWEEN TWO COUNTER CURRENT SCRUBBER STAGES IN A MULTIPLE STAGE TREATMENT CONFIGURATION
|
LIMITED REMOVAL EFFICIENCY
INCREASED CLOGGING POTENTIAL
|
| CROSS-FLOW PACKED BED SCRUBBERS |
USED FOR REMOVAL OF WATER SOLUBLE COMPOUNDS LIKE SULFIDES AND ACID FUMES
USED WHERE HEIGHT IS A LIMITING CONSIDERATION
|
WHEN IMPROPERLY MAINTAINED, IT HAS A GREATER POTENTIAL TO ALLOW AIR TO PASS THROUGH WITH OUT BEING TREATED |
| COARSE MIST SCRUBBERS |
USEFUL FOR FIRE ABATEMENT AND GAS STREAM COOLING |
MARGINALLY USEFUL FOR REMOVAL OF WATER SOLUBLE COMPOUNDS |
| CARBON (OR OTHER SUBSTRATE) ADSORBER |
REMOVES A WIDE RANGE OF COMPOUNDS
EFFICIENCY CAN BE IMPROVED BY IMPREGNATION WITH OTHER COMPOUNDS LIKE:
- SODIUM HYDROXIDE
- POTASSIUM PERMANGANATE
- SULFURIC ACID
- PHOSPHORIC ACID
- POTASSIUM CARBONATE
- IRON OXIDE
- POTASSIUM IODIDE
- TRIETHYLENE DIAMINE (TEDA)
- SULFUR
- SILVER
- ZINK OXIDE
- MERCURY CHLORIDE
- ZINK ACETATE
- NOBLE METALS
|
CARBON MUST BE PERIODICALLY REGENERATED OR REPLACE
MOISTURE IN THE AIRSTREAM CLOGS THE CARBON
WHEN SATURATED WITH ORGANICS IT MUST BE COOLED BY CONTINUOUS AIR FLOW OR IT WILL SPONTANEOUSLY COMBUST
|
| VENTURI |
TYPICALLY USED TO ENTRAIN WATER SOLUBLE GAS LIKE CHLORINE INTO LIQUID STREAM |
HIGH OPERATIONAL COSTS
|
| FLAIR |
WIDE RANGE OF APPLICATIONS |
TYPICALLY EXPENSIVE TO OPERATE IF ADDITIONAL FUEL IS REQUIRED TO MAINTAIN COMBUSTION |
| REGENERATIVE THERMAL OXIDIZER |
WIDE RANGE OF APPLICATIONS |
TYPICALLY EXPENSIVE TO OPERATE IF ADDITIONAL FUEL IS REQUIRED TO MAINTAIN COMBUSTION
SUBJECT TO OXIDATION BY CORROSIVE COMPOUNDS IN GAS STREAM
|
| REGENERATIVE THERMAL OXIDIZER
BED TYPE BIOSCRUBBER / BIOREACTOR
|
TYPICALLY USED FOR TREATMENT OF FOUL AIR WITH LOW VOLATILE ORGANIC COMPOUND (VOC) OR SULFIDE CONCENTRATIONS
SEE DETAILED LIST OF VOC'S IN TABLE OF COMPOUNDS
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REQUIRES LARGE LAND AREA
VULNERABLE TO VARIATIONS IN MOISTURE
ORGANIC BEDS HAVE LIMITED LIFE
EASILY CLOGGED BY PARTICULATE OR BIOMASS
LEACHATE FROM BED TYPICALLY REQUIRES TREATMENT PRIOR TO DISPOSAL
|
| BIOSCRUBBER / BIOFILTER IN VESSEL |
TYPICALLY USED FOR TREATMENT OF FOUL AIR WITH CONSISTENT VOLATILE ORGANIC COMPOUND (VOC) OR SULFIDE CONCENTRATIONS
SMALLER "FOOTPRINT" THAN BED TYPE BIOSCRUBBER
|
BED CLOGGING CAN OCCUR IF SUBSTRATE SUPPORTING BIOLOGICAL GROWTH IS NOT SIZED CORRECTLY AND MADE OF A MATERIAL THAT IS COMPATIBLE WITH COMPOUND BEING TREATED
VOLCANIC ROCK & OTHER POROUS MINERAL SUBSTRATES ARE SUBJECT TO DECOMPOSITION IN ACID ENVIRONMENTS. THEY ARE EASILY CLOGGED BY PARTICULATE LADEN AIR AND THEY ARE HEAVY REQUIRING ADDITIONAL STRUCTURAL SUPPORT
STRUCTURED PACKING AND OTHER PLASTIC SUBSTRATES MAY BE TOO SMOOTH TO ALLOW BIOLOGICAL GROWTH ATTACHMENT AND MAY HAVE GEOMETRIES THAT PROMOTE CLOGGING
LEACHATE FROM BED TYPICALLY REQUIRES TREATMENT PRIOR TO DISPOSAL
|
| BIOSCRUBBER / BIOFILTER WITH CARBON ADSORBER |
TYPICALLY USED FOR TREATMENT OF FOUL AIR WITH INCONSISTENT VOLATILE ORGANIC COMPOUND (VOC) OR SULFIDE CONCENTRATIONS
THE CARBON ACTS LIKE A BUFFER TO EVEN OUT THE LOADING ON THE BIOSCRUBBER / BIOFILTER
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HIGHER EQUIPMENT COST THAN CONVENTIONAL BIOFILTER
WILL BECOME CLOGGED BY PARTICULATE LADEN AIR
LEACHATE FROM BED TYPICALLY REQUIRES TREATMENT PRIOR TO DISPOSAL
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