Chemical Engineering Design Feasibility Study Site Selection - Plant Layout and environmental issue...
-
Upload
stuart-baldwin -
Category
Documents
-
view
238 -
download
10
Transcript of Chemical Engineering Design Feasibility Study Site Selection - Plant Layout and environmental issue...
Chemical Engineering Design
Feasibility StudyFeasibility Study
Site Selection- Plant Layout and environmental issue- Site Location
Chemical Engineering Design
Site Design Issues: Site Design Issues: Layout andLayout and
Environmental ImpactEnvironmental Impact
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Site Selection & LayoutSite Selection & Layout
• Where will the project or plant be built?Where will the project or plant be built?
• How much land and how many buildings will be needed?How much land and how many buildings will be needed?
• How will the process equipment be laid out?How will the process equipment be laid out?
• How will the plant be connected to offsites and storage How will the plant be connected to offsites and storage areas?areas?
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Site Selection FactorsSite Selection Factors
Exercise: What factors do companies consider when deciding where to build a new plant?
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Site Selection FactorsSite Selection Factors
Availability of skilled labor
Raw materialsavailability
Tax regime
Political and strategic factorsNearness to
marketsTransport facilities
(Roads, ports, rail, pipelines)
Resource availability(Water, land, fuel, power)
Cost of labor(and other fixed costs)
Environmental impact
Not all trade-offs will be captured by economic analysis!© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Site and Plant LayoutSite and Plant Layout
• Site layout goals:Site layout goals:– Easy access to plants for workers, emergency respondersEasy access to plants for workers, emergency responders
• Lots of access roads, space between unitsLots of access roads, space between units
– Buildings located away from hazardous areasBuildings located away from hazardous areas– Allow space between process unitsAllow space between process units
• At least 30m, more if processes are hazardousAt least 30m, more if processes are hazardous
– Storage areas have access to transportation infrastructureStorage areas have access to transportation infrastructure• Locate near main road entrance so tanker drivers don’t have to drive Locate near main road entrance so tanker drivers don’t have to drive
through the plantthrough the plant
• Stores also need shipping and receiving areaStores also need shipping and receiving area
– Smooth flow of materials between plants, storage, utility plantSmooth flow of materials between plants, storage, utility plant• Reduce length of pipe runs, utility system heat lossesReduce length of pipe runs, utility system heat losses
– Make allowance for future plant expansionMake allowance for future plant expansion
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Example Site LayoutExample Site Layout
Major road
Available area
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Example Site LayoutExample Site Layout
Major road
GatehouseTank farm
Rail siding
• Locate tank farm with access to road and rail• Preferably also so that prevailing wind carries vapors away from plant
Prev
ailin
g w
ind
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Example Site LayoutExample Site Layout
Major road
GatehouseTank farm
Rail siding
S&RStores
Maintenance Workshops
Canteen
Labs
Offices
FireHouse
Access road
High-occupancy buildings need road access & parking, should be upwind of plant
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Example Site LayoutExample Site Layout
Major roadEmergency access gates, normally closed
GatehouseTank farm
Rail siding
S&RStores
Maintenance Workshops
Canteen
Labs
Offices
FireHouse
• Grid of roads for all-round access to plants• Access to plants restricted except in emergency
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Example Site LayoutExample Site Layout
Major road
GatehouseTank farm
Rail siding
S&RStores
Maintenance Workshops
Canteen
Labs
Offices
FireHouse
Plant 3
Plant 2Area 2
Plant 2Area 1
Plant 1
UtilityPlant
Plant 4
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Example Site LayoutExample Site Layout
Major road
GatehouseTank farm
Rail siding
S&RStores
Maintenance Workshops
Canteen
Labs
Offices
FireHouse
Plant 3
Plant 2Area 2
Plant 2Area 1
Plant 1
UtilityPlant
Plant 4
Areas to allow for future expansion© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Example Site LayoutExample Site Layout
Major road
GatehouseTank farm
Rail siding
S&RStores
Maintenance Workshops
Canteen
Labs
Offices
FireHouse
Plant 3
Plant 2Area 2
Plant 2Area 1
Plant 1
UtilityPlant
Plant 4
Pipe bridge
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Plant LayoutPlant Layout• Usually carried out using CAD toolsUsually carried out using CAD tools
• Locate major equipment items to minimize pipe runs, allow Locate major equipment items to minimize pipe runs, allow ease of access for maintenanceease of access for maintenance
• Locate at grade:Locate at grade:• Large items with special foundation requirements or frequent Large items with special foundation requirements or frequent
maintenance needsmaintenance needs• Equipment subject to vibration (pumps, compressors, solids handling)Equipment subject to vibration (pumps, compressors, solids handling)
• Make use of open 3-D steel structure so not all items are at Make use of open 3-D steel structure so not all items are at grade (when practical to do so) grade (when practical to do so)
• Locate control room away from noise, hazardsLocate control room away from noise, hazards
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Environmental ImpactEnvironmental Impact
Processes must meet acceptable environmental standards Processes must meet acceptable environmental standards because:because:
• It is required by lawIt is required by law
• The costs (human, social, economic) of non-compliance The costs (human, social, economic) of non-compliance can be catastrophiccan be catastrophic
• Lax attitudes are reflected in insurance premiums, stock Lax attitudes are reflected in insurance premiums, stock pricesprices
• Moral and ethical obligationsMoral and ethical obligations
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Environmental RegulationsEnvironmental Regulations
• Emissions from chemical plants are regulated by Emissions from chemical plants are regulated by national government (e.g. US EPA) and local national government (e.g. US EPA) and local government agencies (e.g. SCAQMD)government agencies (e.g. SCAQMD)
• Chemical plant management mustChemical plant management must– Monitor and document waste streams discharged to the Monitor and document waste streams discharged to the
environmentenvironment– Maintain the necessary permits from the relevant government Maintain the necessary permits from the relevant government
agenciesagencies– Pay fines or other penalties to address any violationsPay fines or other penalties to address any violations
• Government agencies are able to order a facility to Government agencies are able to order a facility to cease operating & send management to jail in extreme cease operating & send management to jail in extreme casescases
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Environmental ImpactEnvironmental Impact
• Air pollutionAir pollution
• Water PollutionWater Pollution
• Hazardous WasteHazardous Waste
• Waste MinimizationWaste Minimization
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Environmental ImpactEnvironmental Impact
• Air pollutionAir pollution
• Water PollutionWater Pollution
• Hazardous WasteHazardous Waste
• Waste MinimizationWaste Minimization
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air PollutionAir Pollution
Common air pollutants from chemical plants include:Common air pollutants from chemical plants include:
• SOSOxx
• NONOxx
• COCO22
• Particulates (PMParticulates (PM1010, PM, PM2.52.5))
• Volatile Organic Compounds (VOC)Volatile Organic Compounds (VOC)
• Chlorine compounds (less common)Chlorine compounds (less common)
From fired heaters, boilers, flares
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air PollutionAir Pollution
Common air pollutants from chemical plants include:Common air pollutants from chemical plants include:
• SOSOxx
• NONOxx
• COCO22
• Particulates (PMParticulates (PM1010, PM, PM2.52.5))
• Volatile Organic Compounds (VOC)Volatile Organic Compounds (VOC)
• Chlorine compounds (less common)Chlorine compounds (less common)
From solids handling operations
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air PollutionAir Pollution
Common air pollutants from chemical plants include:Common air pollutants from chemical plants include:
• SOSOxx
• NONOxx
• COCO22
• Particulates (PMParticulates (PM1010, PM, PM2.52.5))
• Volatile Organic Compounds (VOC)Volatile Organic Compounds (VOC)
• Chlorine compounds (less common)Chlorine compounds (less common)
From vents, tanks, fugitive emissions
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air PollutionAir Pollution
Impacts of these air pollutants include:Impacts of these air pollutants include:
• SOSOxx
• NONOxx
• COCO22
• Particulates (PMParticulates (PM1010, PM, PM2.52.5))
• Volatile Organic Compounds (VOC)Volatile Organic Compounds (VOC)
• Chlorine compounds (less common)Chlorine compounds (less common)
Acid rain
Acid rain, ozone, greenhouse gas
Acid rain, greenhouse gas
Smog
Smog, ozone, GHG
Ozone, GHG
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
How Ozone is FormedHow Ozone is Formed
SolarEnergy
Ground Level
Ozone (O3)Formation
Sources: Houston Regional Monitoring andBusiness Coalition for Clean Air
14%
8 %9 %
69%Trees, Shrubs, Swamps
Industry
Off-RoadCars & Trucks
Industry
Cars & TrucksOff-Road
Natural Sources
Note: large amount of NOx produced by industry
Note: large amount of NOx produced by industry
VOC’sVOC’sNOxNOx
FAVORABLE CONDITIONS
•High temperature
•Low wind speed
•Low cloud cover
FAVORABLE CONDITIONS
•High temperature
•Low wind speed
•Low cloud cover
OXYGENOXYGEN
30 %18 %
2 %
50 %
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
• The basic principles of the “Greenhouse Effect” are well The basic principles of the “Greenhouse Effect” are well understood understood – Radiation from the earth is absorbed by gasesRadiation from the earth is absorbed by gases– Acts like insulation and maintains habitable surface temperatures Acts like insulation and maintains habitable surface temperatures
on earthon earth– Water vapor causes 80-90% of this effectWater vapor causes 80-90% of this effect
• The “Enhanced” Greenhouse Effect is the concern (i.e., The “Enhanced” Greenhouse Effect is the concern (i.e., increased COincreased CO22 from human activities creates “forcing” large from human activities creates “forcing” large enough to cause global warming)enough to cause global warming)
• The remaining uncertainties are The remaining uncertainties are – How much warmer will it get?How much warmer will it get?– What will be the consequences? What will be the consequences?
Global WarmingGlobal Warming
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
• Six main Greenhouse Gases (GHG) and their Global Six main Greenhouse Gases (GHG) and their Global Warming Potentials (GWP) - “ability to trap the sun’s Warming Potentials (GWP) - “ability to trap the sun’s heat”heat”— COCO2 2 - 1.0 (highest volume, most concern!) - 1.0 (highest volume, most concern!)
— CHCH4 4 - - 2121— NN22O - 310O - 310— Others: HFC’s, PFC’s SFOthers: HFC’s, PFC’s SF66 - range 140 - 23,900 - range 140 - 23,900
• 1997 Kyoto Protocol - reduce GHGs 5.2% worldwide 1997 Kyoto Protocol - reduce GHGs 5.2% worldwide from 1990 levels by 2008-2012. from 1990 levels by 2008-2012. — U.S. did not sign, India and China did not have targetsU.S. did not sign, India and China did not have targets— Most of those that did sign will not meet targetsMost of those that did sign will not meet targets— Many countries are imposing COMany countries are imposing CO22 taxes though taxes though— Governments are creating greater incentives for energy Governments are creating greater incentives for energy
efficiency & renewable energy sourcesefficiency & renewable energy sources
Global WarmingGlobal Warming
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
TITLESUBJECT
IProvisions for Attainment and Maintenance of National Ambient Air Quality Standards
IIProvisions Relating to Mobile Sources
IIIHazardous Air Pollutants
IVAcid Deposition Control
VPermits
VIStratospheric Ozone Protection
VII-XI Enforcement, Research, Miscellaneous
U.S. Clean Air Act Amendments of 1990U.S. Clean Air Act Amendments of 1990The Clean Air Act (CAA); 42 U.S.C. s/s 7401 et seq. (1970)The Clean Air Act (CAA); 42 U.S.C. s/s 7401 et seq. (1970)
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air Pollution Regulatory ApproachesAir Pollution Regulatory Approaches• Goal OrientedGoal Oriented
– U.S. National Ambient Air Quality Standards (NAAQS)U.S. National Ambient Air Quality Standards (NAAQS)• EPA sets allowable ambient levels for seven contaminants EPA sets allowable ambient levels for seven contaminants
– Ozone, CO, lead, nitrogen dioxide, sulfur dioxide, PM10 PM2.5Ozone, CO, lead, nitrogen dioxide, sulfur dioxide, PM10 PM2.5• Set two levels based on receptorSet two levels based on receptor
– Primary Standard (for public health, baseline levels) Primary Standard (for public health, baseline levels) – Secondary Standard (for public welfare, more strict)Secondary Standard (for public welfare, more strict)
• ““AttainmentAttainment”” or or ““Non-attainmentNon-attainment” ” AreasAreas
• Technology BasedTechnology Based– U.S. National Emission Standards for Hazardous Air Pollutants U.S. National Emission Standards for Hazardous Air Pollutants
(NESHAP)(NESHAP)• Standards based on best 12% controlled facilities in each industryStandards based on best 12% controlled facilities in each industry• 189 Hazardous Air Pollutants (HAPs)189 Hazardous Air Pollutants (HAPs)
– Maximum Available Control Technology Rule (MACT) of CAAAMaximum Available Control Technology Rule (MACT) of CAAA• Refinery MACT1995 – organics from vents, leaks, tanks, drainsRefinery MACT1995 – organics from vents, leaks, tanks, drains• Refinery MACT II 2002 – vents of non-organicsRefinery MACT II 2002 – vents of non-organics
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Impact of Clean Air Act AmendmentsImpact of Clean Air Act Amendments
Stoddard, J.L., Kahl, J.S., Deviney, F.A., DeWalle, D.R., Driscoll, C.T., Herlihy, A.T., Kellogg, J.H., Murdoch, P.S., Webb, J.R., & Webster, K.E. Response of Surface Water Chemistry to the Clean Air Act Amendments of 1990. U.S. EPA., Research Triangle Park, N.C., 2003.
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Impact of Clean Air Act AmendmentsImpact of Clean Air Act Amendments
• Data shows Data shows large impact large impact on surface on surface water aciditywater acidity
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Impact of Clean Air Act AmendmentsImpact of Clean Air Act Amendments
• Less impact on Less impact on NONOxx as this was as this was
not regulated as not regulated as tightlytightly
• As of July 2007, As of July 2007, USA had no NOUSA had no NOxx
non-attainment non-attainment areasareas
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
• 0.08 ppm 8 hr standard
• Federal reformulated gasoline (RFG) is mandatory in non-attainment areas
• > 1/3 of U.S.A. is currently on RFG
Ozone Non-AttainmentOzone Non-Attainment
Source www.epa.gov
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Ozone ReductionOzone Reduction
• Most VOCs Most VOCs come from plantscome from plants
• Scope for Scope for reducing reducing industrial VOC industrial VOC emissions is emissions is smallsmall
• Focus has now Focus has now shifted towards shifted towards more stringent more stringent controls on NOcontrols on NOxx
SolarEnergy
Ground LevelOzone (O3)Formation
Sources: Houston Regional Monitoring andBusiness Coalition for Clean Air
14%
8 %9 %
69%Trees, Shrubs, Swamps
Industry
Off-RoadCars & Trucks
Industry
Cars & TrucksOff-Road
Natural Sources
VOC’sVOC’sNOxNOx
FAVORABLE CONDITIONS
•High temperature
•Low wind speed
•Low cloud cover
FAVORABLE CONDITIONS
•High temperature
•Low wind speed
•Low cloud cover
OXYGENOXYGEN
30 %18 %
2 %
50 %
SolarEnergy
Ground LevelOzone (O3)Formation
Sources: Houston Regional Monitoring andBusiness Coalition for Clean Air
14%
8 %9 %
69%Trees, Shrubs, Swamps
Industry
Off-RoadCars & Trucks
14%
8 %9 %
69%Trees, Shrubs, Swamps
Industry
Off-RoadCars & Trucks
Industry
Cars & TrucksOff-Road
Natural Sources
Industry
Cars & TrucksOff-Road
Natural Sources
VOC’sVOC’sNOxNOx
FAVORABLE CONDITIONS
•High temperature
•Low wind speed
•Low cloud cover
FAVORABLE CONDITIONS
•High temperature
•Low wind speed
•Low cloud cover
OXYGENOXYGEN
30 %18 %
2 %
50 %
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
• SOx SOx – Easiest method is to remove S from fuel Easiest method is to remove S from fuel
• Substitute Nat Gas or low sulfur heating oil for bunker oilSubstitute Nat Gas or low sulfur heating oil for bunker oil• Amine scrub fuel gas more deeply: U.S. EPA - 162 ppm HAmine scrub fuel gas more deeply: U.S. EPA - 162 ppm H22S in fuel gas (20 S in fuel gas (20
ppm SOppm SO22 in flue) in flue)
– More expensive is SOMore expensive is SOxx capture by flue gas scrubbing (FGD) capture by flue gas scrubbing (FGD)
• NOxNOx– Must distinguish between “fuel” and “thermal” NOMust distinguish between “fuel” and “thermal” NOxx
– Fuel N can be addressed by substitutionFuel N can be addressed by substitution– Lower flame temperatures reduce thermal NOLower flame temperatures reduce thermal NOxx
• Steam injectionSteam injection• Burner designBurner design
– Numerous tail gas treatment processes are availableNumerous tail gas treatment processes are available• Selective catalytic reduction (SCR) with NHSelective catalytic reduction (SCR) with NH33
• Biological treatment, non-catalytic reduction, …Biological treatment, non-catalytic reduction, …
Air Pollutant Emissions ControlAir Pollutant Emissions Control
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Fuel DesulfurizationFuel Desulfurization
• Simple amine Simple amine absorption process absorption process allows fuel gas sulfur to allows fuel gas sulfur to be reduced to 40 ppm be reduced to 40 ppm at low costat low cost
• HH22SS can be reduced to can be reduced to
1 ppm or less using 1 ppm or less using advanced absorption or advanced absorption or adsorbent processesadsorbent processes
Sour gas
Steam
Rich amine
Lean amine
Sweet gas Acid gas
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Catalytic De-NOCatalytic De-NOxx
• Very ExpensiveVery Expensive
• Operates at 400-700°FOperates at 400-700°F
• Used in Retrofits when Used in Retrofits when
Ultra-Low NOUltra-Low NOxx burners burners
cannot be usedcannot be used
• Coupled with air preheat Coupled with air preheat
systemsystem
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air Pollutant Emissions ControlAir Pollutant Emissions Control
• COCO– Reduced by burning using excess air (but bad effect on NOReduced by burning using excess air (but bad effect on NOxx))
• COCO22
– Not currently regulatedNot currently regulated– Can be recovered for underground storage, oil recoveryCan be recovered for underground storage, oil recovery
– COCO22 capture from high pressure gases is relatively cheap capture from high pressure gases is relatively cheap
• Can use amine processes similar to fuel desulfurizationCan use amine processes similar to fuel desulfurization
• Physical solvents such as Selexol are usually cheaperPhysical solvents such as Selexol are usually cheaper
– ““Oxyfuel” combustion using pure oxygen makes COOxyfuel” combustion using pure oxygen makes CO22 collection collection
easier, but is capital intensiveeasier, but is capital intensive
– Cost of COCost of CO22 capture and disposal ~ $40/ton capture and disposal ~ $40/ton
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
• ParticulatesParticulates– Mechanical collectors, e.g. cyclonesMechanical collectors, e.g. cyclones
• For bulk separationFor bulk separation• High loadings, e.g., Catalytic crackingHigh loadings, e.g., Catalytic cracking
– Electrostatic Precipitators (ESPs)Electrostatic Precipitators (ESPs)• Electrical charges cause dust to migrate Electrical charges cause dust to migrate
across streamlines by electrophoresisacross streamlines by electrophoresis• Useful for smaller particlesUseful for smaller particles
– Fabric Filters (“Baghouses”)Fabric Filters (“Baghouses”)• Lower loadingsLower loadings• Higher pressure dropHigher pressure drop
– Wet Gas ScrubbersWet Gas Scrubbers• Low pressure dropLow pressure drop• Transfers air pollutant into liquid streamTransfers air pollutant into liquid stream
Electrostatic Precipitator
Air Pollutant Emissions ControlAir Pollutant Emissions Control
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air Pollutant Emissions Control: VOCsAir Pollutant Emissions Control: VOCs• RecoveryRecovery
– CondensationCondensation• Cheap, but seldom meets targetCheap, but seldom meets target
– ScrubbingScrubbing• Low Low ΔΔP, but creates liquid wasteP, but creates liquid waste
– AdsorptionAdsorption• Effective & expensiveEffective & expensive
• DestructionDestruction– Incineration (purpose, heater or flare)Incineration (purpose, heater or flare)
• Expensive, but can recover fuel valueExpensive, but can recover fuel value
– Catalytic oxidationCatalytic oxidation• Works to very low levels, but catalysts can be sensitiveWorks to very low levels, but catalysts can be sensitive
– Biological treatmentBiological treatment• Cheap, but low throughput and sensitive to toxicsCheap, but low throughput and sensitive to toxics
Adsorption Plant
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air Pollutant Emissions Control: VOCsAir Pollutant Emissions Control: VOCs
• Fugitive emissionsFugitive emissions– Can be 20 – 80% of VOC emissionsCan be 20 – 80% of VOC emissions
• Sources includeSources include– Valves (packings, open line valves)Valves (packings, open line valves)– Seals on pumps, compressors, instrumentsSeals on pumps, compressors, instruments– FlangesFlanges– Pressure relief valvesPressure relief valves– Tank roof sealsTank roof seals
• Can be reduced byCan be reduced by– Improved inspection and maintenanceImproved inspection and maintenance– Better equipmentBetter equipment
• Dual seals, seal-less pumps, dry gas sealsDual seals, seal-less pumps, dry gas seals• Welded instead of flanged jointsWelded instead of flanged joints
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Air Pollutant Emissions Control: VOCsAir Pollutant Emissions Control: VOCs
• VOCs are also emitted from site VOCs are also emitted from site waste waterwaste water– Open drainsOpen drains– Water treatment plantWater treatment plant
• Drains are common on plantDrains are common on plant– Sample pointsSample points– InstrumentsInstruments– MaintenanceMaintenance
• Specify closed drains or water Specify closed drains or water sealed drains when necessarysealed drains when necessary
Seal PotDrain Type
P-Leg TrapDrain Type
Seal
DrainPipe
DrainFunnel
DrainPipe
Seal
12" Diameterx
8" Deep Sump
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Environmental ImpactEnvironmental Impact
• Air pollutionAir pollution
• Water PollutionWater Pollution
• Hazardous WasteHazardous Waste
• Waste MinimizationWaste Minimization
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
1972 Federal Water Pollution Control Act 1972 Federal Water Pollution Control Act (“Clean Water Act” (“Clean Water Act” 33 U.S.C. ss/1251 et seq., 33 U.S.C. ss/1251 et seq., 1977 1977 ))
• Achieve clean water for swimming, boating, and Achieve clean water for swimming, boating, and protecting fish and wildlife by 1983protecting fish and wildlife by 1983
• Amended 1977 and 1987 with focus on toxics and Amended 1977 and 1987 with focus on toxics and water qualitywater quality
• EPA sets water quality standards for pollutants in EPA sets water quality standards for pollutants in surface waterssurface waters
• EPA sets effluent guidelines for each industrial sectorEPA sets effluent guidelines for each industrial sector
• Unlawful to discharge any pollutant into navigable Unlawful to discharge any pollutant into navigable waters without a permitwaters without a permit
U. S. Water Pollution RegulationsU. S. Water Pollution Regulations
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Water pollutants include:Water pollutants include:
• Process waste streamsProcess waste streams– Sour waters (HSour waters (H22S, NHS, NH33))– Salt waters (neutralized streams, softeners, deionizers, etc.)Salt waters (neutralized streams, softeners, deionizers, etc.)– Hydrocarbon contaminated process watersHydrocarbon contaminated process waters– Biologically contaminated waters (e.g. broths)Biologically contaminated waters (e.g. broths)– High ph/low ph waters (spent acids and caustics)High ph/low ph waters (spent acids and caustics)
• Utility waste streamsUtility waste streams– Cooling tower water blowdown (usually largest source)Cooling tower water blowdown (usually largest source)– Boiler blowdownBoiler blowdown
• Run-off streamsRun-off streams– Rain waterRain water– Hydrant flushingHydrant flushing– Equipment washingEquipment washing
Water PollutionWater Pollution
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Gravity Sand Filter
Clarifier
Biological Treatment -
Aeration
Wastewater Treatment SystemsWastewater Treatment Systems
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
• Process waste streamsProcess waste streams– Sour waters (HSour waters (H22S, NHS, NH33))– Salt waters (neutralized streams, softeners, deionizers, etc.)Salt waters (neutralized streams, softeners, deionizers, etc.)– Hydrocarbon contaminated process watersHydrocarbon contaminated process waters– Biologically contaminated waters (e.g. broths)Biologically contaminated waters (e.g. broths)– High ph/low ph waters (spent acids and caustics)High ph/low ph waters (spent acids and caustics)
• Utility waste streamsUtility waste streams– Cooling tower water blowdown (usually largest source)Cooling tower water blowdown (usually largest source)– Boiler blowdownBoiler blowdown
• Run-off streamsRun-off streams– Rain waterRain water– Hydrant flushingHydrant flushing– Equipment washingEquipment washing
Water PollutionWater Pollution
• Low concentrations of certain highly toxic pollutants set performance limits for biological treatment
• Waste water segregation and use of multiple treatment processes is usually most economical
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Environmental ImpactEnvironmental Impact
• Air pollutionAir pollution
• Water PollutionWater Pollution
• Hazardous WasteHazardous Waste
• Waste MinimizationWaste Minimization
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
• Ultimate objective is to protect groundwater from Ultimate objective is to protect groundwater from contaminationcontamination
• ““Cradle-to-grave”Cradle-to-grave” hazardous waste management hazardous waste management– From identification as a waste to final disposalFrom identification as a waste to final disposal– Generator identifies waste as “hazardous” if it is on a regulatory Generator identifies waste as “hazardous” if it is on a regulatory
list or if it has a characteristic of flammability, toxicity, corrosivity list or if it has a characteristic of flammability, toxicity, corrosivity or reactivityor reactivity
– Hazardous wastes must be labeled and tracked in transportHazardous wastes must be labeled and tracked in transport– Treatment is required to low levels of contaminants Treatment is required to low levels of contaminants – Final disposal into a hazardous waste landfill of residual solid Final disposal into a hazardous waste landfill of residual solid
material (e.g., incinerator ash)material (e.g., incinerator ash)
• Addresses only current and future facilities (not Addresses only current and future facilities (not abandoned or historic sites – see SARA) abandoned or historic sites – see SARA)
U. S. Hazardous Waste RegulationsU. S. Hazardous Waste RegulationsResource Conservation and Recovery Act (RCRA) Resource Conservation and Recovery Act (RCRA)
42 U.S.C. s/s 321 et seq. 197642 U.S.C. s/s 321 et seq. 1976
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
• IncinerationIncineration– Usually not cheapest, but may recover fuel valueUsually not cheapest, but may recover fuel value– Possible issue with chlorine containing wastes and dioxin formationPossible issue with chlorine containing wastes and dioxin formation
• LandfillLandfill– Usually after pretreatment such as dewatering, neutralization, biotreatment, Usually after pretreatment such as dewatering, neutralization, biotreatment,
extraction, vitrification, fixation, etc.extraction, vitrification, fixation, etc.– If hazardous by regulatory definition then requires treatment to reduce If hazardous by regulatory definition then requires treatment to reduce
contaminants to very low levelcontaminants to very low level
• Land Treatment (“land-farming”)Land Treatment (“land-farming”)– Sludge is spread over a large area of land and degraded by soil microbesSludge is spread over a large area of land and degraded by soil microbes– Useful for oil sludges, spent adsorbents, etc.Useful for oil sludges, spent adsorbents, etc.– Care must be taken to control waters to prevent groundwater contaminationCare must be taken to control waters to prevent groundwater contamination
• RecycleRecycle– If a viable case can be made, e.g., rubber, aluminumIf a viable case can be made, e.g., rubber, aluminum
Final Disposal of WastesFinal Disposal of Wastes
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Typical Treatment for SpecificTypical Treatment for SpecificOil Refinery Solid WastesOil Refinery Solid Wastes
SOLID WASTE TYPICAL TREATMENT
Tank bottom sludges Oil recovery, incineration, fixation
Cooling tower sludges Fixation
Exchanger bundle cleaning sludges Fixation
Coke fines Incineration, fixation
Spent catalysts Neutralization, metals recovery, fixation
Chemical precipitation sludges Incineration, fixation
Silica gels Fixation
Organic wastes Incineration
Waste biological sludges Dewatering, land application, incineration
Pathogenic wastes Incineration
API separator sludge/waste oils Oil recovery, incineration and fixation
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Hazardous Waste from Abandoned Hazardous Waste from Abandoned OperationsOperations
Comprehensive Environmental Response, Compensation, Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) and Liability Act (CERCLA or Superfund) 42 U.S.C. s/s 9601 et seq. 42 U.S.C. s/s 9601 et seq. (1980) (1980)
• Created a tax on the chemical and petroleum industries for cleaning up Created a tax on the chemical and petroleum industries for cleaning up abandoned or uncontrolled hazardous waste sitesabandoned or uncontrolled hazardous waste sites
• Established prohibitions and requirements concerning closed and Established prohibitions and requirements concerning closed and abandoned hazardous waste sites and provided for liability of persons abandoned hazardous waste sites and provided for liability of persons responsible for releases of hazardous waste at these sitesresponsible for releases of hazardous waste at these sites
The law authorized two kinds of response actions:The law authorized two kinds of response actions:
• Short-term removals, where actions may be taken to address releases Short-term removals, where actions may be taken to address releases or threatened releases requiring prompt response.or threatened releases requiring prompt response.
• Long-term remedial response actions, that permanently and Long-term remedial response actions, that permanently and significantly reduce the dangers associated with releases or threats of significantly reduce the dangers associated with releases or threats of releases of hazardous substances that are serious, but not immediately releases of hazardous substances that are serious, but not immediately life threatening. life threatening.
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
The Superfund Amendments and The Superfund Amendments and Reauthorization Act (SARA) Reauthorization Act (SARA)
42 U.S.C.9601 et seq. (1986)42 U.S.C.9601 et seq. (1986) • Amended CERCLA and made additions to the programAmended CERCLA and made additions to the program
• Stressed the importance of permanent remedies and innovative treatment Stressed the importance of permanent remedies and innovative treatment technologies in cleaning up hazardous waste sitestechnologies in cleaning up hazardous waste sites
• Required Superfund actions to consider the standards and requirements found in Required Superfund actions to consider the standards and requirements found in other State and Federal environmental laws and regulationsother State and Federal environmental laws and regulations
• Increased State involvement in every phase of the Superfund programIncreased State involvement in every phase of the Superfund program
• Increased the focus on human health problems posed by hazardous waste sitesIncreased the focus on human health problems posed by hazardous waste sites
• Encouraged greater citizen participation in making decisions on how sites should Encouraged greater citizen participation in making decisions on how sites should be cleaned upbe cleaned up
• Increased the size of the trust fund to $8.5 billion.Increased the size of the trust fund to $8.5 billion.
• Required EPA to revise the Hazard Ranking System (HRS) to ensure that it Required EPA to revise the Hazard Ranking System (HRS) to ensure that it accurately assessed the relative degree of risk to human health and the accurately assessed the relative degree of risk to human health and the environment posed by uncontrolled hazardous waste sitesenvironment posed by uncontrolled hazardous waste sites
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Environmental ImpactEnvironmental Impact
• Air pollutionAir pollution
• Water PollutionWater Pollution
• Hazardous WasteHazardous Waste
• Waste MinimizationWaste Minimization
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Waste MinimizationWaste Minimization
• Instead of treating the waste at the “end of pipe” we try Instead of treating the waste at the “end of pipe” we try to reduce or eliminate it by better process designto reduce or eliminate it by better process design
• The heirarchy of waste management approaches is:The heirarchy of waste management approaches is:
Source Reduction
Recycle
Disposal
Treatment
Don’t make it in the first place – Best Practice
Find a use for the waste stream
Reduce the severity of impact
Meet the requirements of the law
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Source Reduction StrategiesSource Reduction Strategies• Reduce feed impurities by purificationReduce feed impurities by purification
– Usually leads to fewer components in wasteUsually leads to fewer components in waste
– Can reduce purge and vent requirementsCan reduce purge and vent requirements
• Protect catalysts and adsorbentsProtect catalysts and adsorbents– Use guard beds or scrubbers to prevent deactivationUse guard beds or scrubbers to prevent deactivation
• Eliminate extraneous materials used for separationEliminate extraneous materials used for separation– Mass separating agents such as solventsMass separating agents such as solvents
• Increase recovery from separationsIncrease recovery from separations– Enhance product recoveryEnhance product recovery
– Purify recycle streamsPurify recycle streams
• Improve fuel qualityImprove fuel quality
Partly taken from: Smith, R. & Petela, E. Waste Minimization in the Process Industries: 3. Separation and Recycle Systems Chem. Eng., 513, 13, 1991
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Waste Minimization 5-Step ReviewWaste Minimization 5-Step Review
• Step 1: Identify waste Step 1: Identify waste componentscomponents for regulatory impactfor regulatory impact
• Step 2: Identify process Step 2: Identify process waste waste streamsstreams for size, economic impact for size, economic impact
• Step 3: List Step 3: List root causesroot causes of wastes of wastes
• Step 4: List & analyze Step 4: List & analyze modificationsmodifications to address root causesto address root causes
• Step 5: Prioritize and Step 5: Prioritize and implementimplement the the best solutionsbest solutions
• These steps can be addressed by putting together an Effluent Summary
• At the design stage, many effluents will be estimated rather than measured, but the ability to make changes is greater
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Effluent SummaryEffluent Summary
• Lists regulated Lists regulated pollutants and pollutants and summarizes summarizes sources, quantitiessources, quantities
• Sections for Sections for process and process and associated offsitesassociated offsites
• Helps to focus and Helps to focus and prioritize pollution prioritize pollution prevention activitiesprevention activities
Project Name
Project Number Sheet 1REV DATE BY APVD REV DATE BY APVD
Owner's NamePlant Location Units English MetricCase Description
Pollutant Process Source (Stream No. if avail.) Measurement (estimate) method Continuous / IntermittentNitrogen Oxides
TotalSulfur Oxides
TotalParticulate matter
TotalVolatile organic compounds
TotalHAPs (list by name)
Stream Name Process Source (Stream No. if avail.) Water flow kg/day Contaminant
Stream Name Process Source (Stream No. if avail.) Measurement (estimate) method Component
Stream Name Process Source (Stream No. if avail.) Measurement (estimate) method Component
Vapor Emissions
Solid Waste Streamskg/day kg/yr
Organic Waste Streamskg/day kg/yr
Aqueous Waste StreamsContaminent flow kg/day Contaminent flow metric ton/yr Concentration (wt%)
PROCESS EMISSIONS
kg/day kg/yr Regulatory Status
Address
Company Name
Form XXXXX-YY-ZZ
EFFLUENT SUMMARY
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Additional Reasons for Estimating Additional Reasons for Estimating EffluentsEffluents
• May be a requirement for getting National / Local May be a requirement for getting National / Local Government permits to operate the plantGovernment permits to operate the plant
• May be a requirement for getting insuranceMay be a requirement for getting insurance
• May be a requirement for obtaining loans or securing May be a requirement for obtaining loans or securing funding for constructionfunding for construction
• May be a regulatory requirementMay be a regulatory requirement
• May help to anticipate or avoid large mitigation costsMay help to anticipate or avoid large mitigation costs
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Environmental Impact: ConclusionEnvironmental Impact: Conclusion
• Be “environmentally responsible” as a design engineerBe “environmentally responsible” as a design engineer– Understand the environmental issuesUnderstand the environmental issues
– Understand your legal and ethical obligationsUnderstand your legal and ethical obligations
– Understand the best available control and remediation technologiesUnderstand the best available control and remediation technologies
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Process IntensificationProcess Intensification
• Process intensification means carrying out Process intensification means carrying out the samethe same process process operation using operation using smallersmaller equipment or smaller inventories equipment or smaller inventories
• This is an important strategy for increasing the inherent safety of a This is an important strategy for increasing the inherent safety of a processprocess
• Process intensification is Process intensification is not not the same thing as process the same thing as process miniaturizationminiaturization
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Process Intensification TechniquesProcess Intensification Techniques
• Just-in-time manufacture Just-in-time manufacture – lower inventories– lower inventories
• In-line mixers In-line mixers – lower inventories– lower inventories
• Structured column packings Structured column packings – less hold-up– less hold-up
• Plate heat exchangers Plate heat exchangers – lower – lower ΔΔT, less volumeT, less volume
• Monolith catalysts Monolith catalysts – lower – lower ΔΔT, better mass tfrT, better mass tfr
• Micro-channel reactors Micro-channel reactors – better mass tfr– better mass tfr
• HiGee fractionation HiGee fractionation – better mass tfr– better mass tfr
Incr
easi
ng C
omm
erci
al A
ccep
tanc
e
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Process Intensification vs. Process Process Intensification vs. Process MiniaturisationMiniaturisation
• Which is safer & why?Which is safer & why?
100 /yr
10 /yr 10 /yr 10 /yr
10 /yr 10 /yr 10 /yr
10 /yr 10 /yr 10 /yr
10 /yr
Option A Option B
Just making things smaller doesn’t make them safer if you need more of them to do the same job. The probability of
a failure event increases proportional to the number of systems in parallel
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
Process Intensification vs. Process Process Intensification vs. Process MiniaturisationMiniaturisation
• Which has lowest environmental impact & why?Which has lowest environmental impact & why?
100 /yr
10 /yr 10 /yr 10 /yr
10 /yr 10 /yr 10 /yr
10 /yr 10 /yr 10 /yr
10 /yr
Option A Option B
It is easier to monitor and control emissions from a single point source than from many distributed sources. It is also
easier to deploy “end-of-pipe” treatment processes
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy
Chemical Engineering Design
RECAPRECAP
1)1) General outlook on the product, regionally and General outlook on the product, regionally and worldwide (uses, current supply, demand, price, worldwide (uses, current supply, demand, price, competitors, customer, raw materials etc)competitors, customer, raw materials etc)
2)2) Site location (consider all the factors mentioned) – Site location (consider all the factors mentioned) – compare 3 alternativescompare 3 alternatives
3)3) Site layoutSite layout
4)4) Financial analysisFinancial analysis
Chemical Engineering Design
Questions ?Questions ?
© 2012 G.P. Towler / UOP. For educational use in conjunction with Towler & Sinnott Chemical Engineering Design only. Do not copy