an alternative to vacuum enhanced multi-phase … · 2016-01-22 · flow multi-phase flow...
TRANSCRIPT
AN ALTERNATIVE
TO VACUUM ENHANCED
MULTI-PHASE EXTRACTION
Allan Shea, P.Eng.
October 2003
AN ALTERNATIVE
TO VACUUM ENHANCED
MULTI-PHASE EXTRACTION
Allan Shea, P.Eng.
October 2003
BACKGROUNDBACKGROUND
Above ground portion ofmechanical remediation systemsAbove ground portion ofmechanical remediation systems
Allan SheaAllan Shea
Experience has been mainly with:Experience has been mainly with:
At sites that:
� Are contaminated with light hydrocarbons� Vary greatly in size� May have Light Non-Aqueous Phase Liquid (LNAPL) present
At sites that:
� Are contaminated with light hydrocarbons� Vary greatly in size� May have Light Non-Aqueous Phase Liquid (LNAPL) present
10 years ago, VacuumEnhanced Multi-PhaseExtraction (VEMPE) promisedspeedy and economicalremediation of volatilehydrocarbons
10 years ago, VacuumEnhanced Multi-PhaseExtraction (VEMPE) promisedspeedy and economicalremediation of volatilehydrocarbons
VEMPEVEMPE BACKGROUNDBACKGROUND
But some problems havenot been fully resolvedBut some problems havenot been fully resolved
DEFINITIONSDEFINITIONS
Vacuum Enhanced Multi-PhaseExtraction (VEMPE)Vacuum Enhanced Multi-PhaseExtraction (VEMPE)
VEMPEVEMPE
Soil Vapour Extraction (SVE) Soil Vapour Extraction (SVE)
Liquids Pumping Liquids Pumping
Dual-Phase Extraction (DPE) Dual-Phase Extraction (DPE)
Liquid Ring Pump (LRP) Liquid Ring Pump (LRP)
SYSTEMOVERVIEW
SYSTEMOVERVIEW
Use vacuum to extract contaminantsfrom the subsurfaceUse vacuum to extract contaminantsfrom the subsurface
VEMPEVEMPE
Wells are typicallyscreened in both thevadose (unsaturated) andthe phreatic (saturated)zones
Wells are typicallyscreened in both thevadose (unsaturated) andthe phreatic (saturated)zones
GRADE
GATE VALVE
AIR INLETVACUUM GUAGE
BENTONITE SEAL
SOLID CASINGEXTRACTION TUBESLOTTED WELL SCREENSAND PACK
WATER
LNAPLVAPOUR
VEMPE Extraction Well
SYSTEMOVERVIEW
SYSTEMOVERVIEW
ATMOSPHERICPRESSURE
VACUUM PRESSURE
ATMOSPHERICPRESSURE
1
2
3
45
6 7
8
9
VAPOR
VAPOR/ GROUNDWATER
GROUNDWATER/ LNAPL
VAPOR
VAPOR/ GROUNDWATER/ LNAPL
GROUNDWATER/ LNAPL
SYSTEMOVERVIEW
SYSTEMOVERVIEW
VEMPE SYSTEMVEMPE SYSTEMCONFIGURATIONCONFIGURATION
VEMPEVEMPE
Volatile Contaminants
LNAPL
Contaminants Dissolvedin Groundwater
Volatile Contaminants
LNAPL
Contaminants Dissolvedin Groundwater
VEMPE IS MOST EFFECTIVE FOR:VEMPE IS MOST EFFECTIVE FOR:
SUITABILITYSUITABILITY
Contaminants that areinaccessible due tolimited permeability ofthe soil
Contaminants that arechemically or physicallybound to soil particles
Contaminants that areinaccessible due tolimited permeability ofthe soil
Contaminants that arechemically or physicallybound to soil particles
VEMPEVEMPE SUITABILITYSUITABILITY
VEMPE IS LEAST EFFECTIVE FOR:VEMPE IS LEAST EFFECTIVE FOR:
The Wrong ToolThe Wrong Tool
ADVANTAGESOF VEMPE
ADVANTAGESOF VEMPE
VEMPE IS POPULAR BECAUSE:VEMPE IS POPULAR BECAUSE:
VEMPEVEMPE
Aggressive treatment
Minimal equipment & piping
Systems available off-the-shelf
Well accepted technology
Aggressive treatment
Minimal equipment & piping
Systems available off-the-shelf
Well accepted technology
More maintenance due to:High operating temperatures
Demands of VEMPE service
More maintenance due to:High operating temperatures
Demands of VEMPE service
VEMPEVEMPE CONCERNSWITH VEMPECONCERNS
WITH VEMPE
Consumes more power due to: LRP seal fluid pumping
Bleed air at wellhead
High piping pressure losses
Consumes more power due to: LRP seal fluid pumping
Bleed air at wellhead
High piping pressure losses
SCFM500SCFM500Vapour flow from wells
SCFM0SCFM150Bleed air flow at wellhead (30%)
/yr$24,500/yr$49,800Electrical power cost
HP28.4HP83.4Total system horsepower
HP2.6 Pneumatic pump air supply horsepower
HP25.8 Vapor blower horsepower
HP83.4LRP horsepower
“Hg10.4“Hg13.2Suction required at pump blower
“Hg0.4“Hg3.2Pressure loss in piping
“Hg10.0“Hg10.0Vacuum required at wells
l/min30l/min30Water flow from wells
DPEVEMPE
ELECTRICAL POWER CONSUMPTIONCOMPARISON
Automatic re-starting can be difficult
Operator attendance usually required
Restart may take considerable time
Can significantly increase operatingcosts
Automatic re-starting can be difficult
Operator attendance usually required
Restart may take considerable time
Can significantly increase operatingcosts
VEMPEVEMPE CONCERNSWITH VEMPECONCERNS
WITH VEMPE
Cost of Unplanned ShutdownsCost of Unplanned Shutdowns
Multi-phase flow in gatheringsystem
Annular or annular mist flowregime is required to transportliquids
High gas velocity is required forannular or annular mist flow
High gas velocity results in highpressure loss
Multi-phase flow in gatheringsystem
Annular or annular mist flowregime is required to transportliquids
High gas velocity is required forannular or annular mist flow
High gas velocity results in highpressure loss
VEMPEVEMPE CONCERNSWITH VEMPECONCERNS
WITH VEMPE
High pressure losses in collection pipingHigh pressure losses in collection piping
MULTI-PHASEFLOW
MULTI-PHASEFLOW
Mmandhane, Gregory and Aziz: A Flow pattern Map for Gas-Liquid Flow in Horizontal Pipes, 1974).
20.0
10.0
1.0
0.1
0.010.01 1.0 10.0 100.0 500.0
SURF
ICIA
L LI
QU
ID V
ELO
CITY
, VSL
, FT/
SEC
SURFICIAL GAS VELOCITY, VSG, FT/SEC
STRATIFIED FLOW
BUBBLE,ELONGATED
BUBBLE FLOWSLUGFLOW
WAVEFLOW
ANNULAR,ANNULAR MIST
FLOW
DISPERSED FLOW
SURFICIAL GAS VELOCITYVSG ( FT/SEC )
SU
RF
ICIA
L L
IQU
ID V
EL
OC
ITY
VS
L (
FT
/SE
C )
MULTI-PHASE FLOW PATTERN MAP
ANNULAR,ANNULAR MIST
FLOW
ANNULAR,ANNULAR MIST
FLOW
AN ALTERNATIVE TO VEMPEAN ALTERNATIVE TO VEMPE
Using Separate Vapour and LiquidExtraction Systems
Vacuum Extraction of Soil Vapour&
Extraction of Liquid by Pumping
Using Separate Vapour and LiquidExtraction Systems
Vacuum Extraction of Soil Vapour&
Extraction of Liquid by Pumping
DUAL-PHASE EXTRACTION (DPE) DUAL-PHASE EXTRACTION (DPE)
DUAL-PHASEEXTRACTIONDUAL-PHASEEXTRACTION
COLLECTION PIPING
INLET VAPOURSEPARATOR
VACUUMPUMP/ BLOWER
GROUNDWATER/ LNAPLTREATMENT/ STORAGE
EXTRACTION WELL
GROUNDWATER/ LNAPLPUMP
VAPOR
VAPOR/ GROUNDWATER/ LNAPL
GROUNDWATER/ LNAPL
LRPLRP
Rotary lobe or claw blower Rotary lobe or claw blower
Regenerative blower Regenerative blower
Vacuum Extraction ofVacuum Extraction ofSoil Vapour (VES) using:Soil Vapour (VES) using:
DUAL-PHASEEXTRACTIONDUAL-PHASEEXTRACTION
COLLECTION PIPING
INLET VAPOURSEPARATOR
VACUUMPUMP/ BLOWER
GROUNDWATER/ LNAPLTREATMENT/ STORAGE
EXTRACTION WELL
GROUNDWATER/ LNAPLPUMP
VAPOR
VAPOR/ GROUNDWATER/ LNAPL
GROUNDWATER/ LNAPL
Pneumatic down-hole pumpsPneumatic down-hole pumps
Electric submersible pumps Electric submersible pumps
Diaphragm Pumps Diaphragm Pumps
Extraction of Liquid byExtraction of Liquid byPumping using:Pumping using:
�Energy efficient
�Electric load split among several motors
�Can be designed so VES system operatesindependently of Liquids Pumping system
�Restarting can be automated
�Reduced pressure losses in wells andvapour collection piping
�Energy efficient
�Electric load split among several motors
�Can be designed so VES system operatesindependently of Liquids Pumping system
�Restarting can be automated
�Reduced pressure losses in wells andvapour collection piping
DPEDPE ADVANTAGESOF DPE
ADVANTAGESOF DPE
Higher Capital Cost Higher Capital Cost
DPEDPE DISADVANTAGESOF DPE
DISADVANTAGESOF DPE
COLLECTION PIPING
INLET VAPOURSEPARATOR
VACUUMPUMP/ BLOWER
GROUNDWATER/ LNAPLTREATMENT/ STORAGE
EXTRACTION WELL
GROUNDWATER/ LNAPLPUMP
VAPOR
VAPOR/ GROUNDWATER/ LNAPL
GROUNDWATER/ LNAPL
More Complex System More Complex System
SUMMARYSUMMARY
VEMPE has become theTechnology of Choice forsites where it is desirable toextract both soil vapour andsubsurface liquids
VEMPE also has Drawbacks
VEMPE has become theTechnology of Choice forsites where it is desirable toextract both soil vapour andsubsurface liquids
VEMPE also has Drawbacks
ATMOSPHERICPRESSURE
VACUUM PRESSURE
ATMOSPHERICPRESSURE
1
2
3
45
6 7
8
9
VAPOR
VAPOR/ GROUNDWATER
GROUNDWATER/ LNAPL
Large vapour and liquid flows are anticipated
It is desirable to substitute a rotary lobe orrotary claw blower for an LRP
Access for maintenance and operationspersonnel is difficult
Application of only vacuum or only liquidpumping to different areas at different times
Large vapour and liquid flows are anticipated
It is desirable to substitute a rotary lobe orrotary claw blower for an LRP
Access for maintenance and operationspersonnel is difficult
Application of only vacuum or only liquidpumping to different areas at different times
DPE offers the Most Advantage where:DPE offers the Most Advantage where:DPE offers the Most Advantage where:
SUMMARYSUMMARY
Think Outside the BoxThink Outside the Box
There is more than OneThere is more than OneSolution to any ProblemSolution to any Problem
Thank You For Your TimeThank You For Your Time