Center for Environmental Research and Technology University of California, Riverside University of California, Davis Performance and Environmental Performance and Environmental Impact Evaluations of Impact Evaluations of Alternative Waste Conversion Alternative Waste Conversion Technologies in California Technologies in California Public Workshop Public Workshop April 14, 2004 April 14, 2004
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Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Performance and Environmental Performance and Environmental Impact Evaluations of Alternative Impact Evaluations of Alternative
Waste Conversion Technologies in Waste Conversion Technologies in CaliforniaCalifornia
Public WorkshopPublic WorkshopApril 14, 2004April 14, 2004
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
IntroductionsIntroductions
California Integrated Waste Management Board Fernando Berton – Project Coordinator
UC Riverside, College of Engineering, Center for Environmental Research and Technology (CE-CERT)
Joseph Norbeck – Co-Principal Investigator
Colin Hackett – Co-Principal Investigator
Tom Durbin – Research Engineer
Bill Welch – Development Engineer
UC Davis, Department of Biological and Agricultural Engineering
Bryan Jenkins - Co-Principal Investigator
Robert Williams – Development Engineer
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Overview•CIWMB Background – Fernando Berton
•University of California Project Overview
– Tom Durbin
•Feedstocks – Tom Durbin, Rob Williams
•Processes and Products
– Tom Durbin, Rob Williams
•Environmental Impacts – Bill Welch
•Conclusions
– Tom Durbin, Rob Williams, Bill Welch
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Materials Being LandfilledMaterials Being Landfilled•1989 legislation goal 50% diversion by 2000 (currently 47%)
•Organics (biogenic and fossil derived)
–Divert 10-13 million tons
–Landfill about 30 million tons
•Paper /cardboard largest category
–Recycle 4-5 million tons, Landfill 11 million tons
•Inorganic Components 8 million tons
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
CIWMB ProgramsCIWMB Programs
• Dec 1999 Colloquy – Started Dialogue
• May 2001 Conversion Technology Forum» Lack of political leadership
» Statutory constraints
» Lack of funding
» Economics and markets
» Lack of data
» Feedstock access
» Public perception & understanding
» Regulatory
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
CIWMB ActionsCIWMB Actions
•May 2001: Directed work in 5 areas:
–Interagency coordination
–Follow-up workshops/symposia
–Leveraging Fed/State $$
–Legislative proposal for small-scale grants and lifecycle analysis research
–Assist applicants in permit process
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
CIWMB Strategic PlanCIWMB Strategic Plan•Conversion technologies could be major tool towards zero waste
“…harnessing the energy potential in “waste” by using new and clean technology to convert the material
directly into green fuel or gas to produce electricity.”
•Strategic Plan Goals & Objectives
–Environmentally preferable technologies
–Promoting new technologies and processes
–Alternative means of diversion, including technologies that result in electricity and fuel
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
University of California, RiversideUniversity of California, Davis
AB 2770 – Penultimate VersionAB 2770 – Penultimate Version
•Administration-sponsored
•Definition, findings, level of credit
•Conforming changes for counting diversion
•Provisions on CEQA, testing residue, etc.
•R&D program
–Lifecycle costs/benefits
–Feedstock amenability with different technologies
–Small-scale grant/R&D program
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
AB 2770 – Chaptered VersionAB 2770 – Chaptered Version
•Gasification Definition
•Lifecycle and market impacts - RTI
•Technical evaluation: UC contract
•Risk assessment issues: OEHHA contract
•Report to Legislature
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Performance and EnvironmentalPerformance and EnvironmentalImpact Evaluations of AlternativeImpact Evaluations of AlternativeWaste Conversion TechnologiesWaste Conversion Technologies
in Californiain California
University of California, RiversideUniversity of California, RiversideCollege of EngineeringCollege of Engineering
Center for Environmental Research and TechnologyCenter for Environmental Research and Technology
University of California, DavisUniversity of California, Davis
Sponsored by:Sponsored by:
California Integrated Waste Management BoardCalifornia Integrated Waste Management Board
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
• About 70 responses received 18 pyrolysis, 22 gasification, 11 biological, 10 plasma
arc, 9 catalytic cracking or other 70% addressed survey questions
• Variety of systems and responses made it difficult to make apples to apples comparisons
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Purpose of WorkshopPurpose of Workshop• Present and explain preliminary findings
• Discuss potential advantages/liabilities of alternative conversion technologies
• Provide a question and answer period
• Obtain feedback from stakeholders
• Discuss needs for additional data/information
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Project TimingProject Timing• Public Workshop – discuss preliminary findings• Working Draft sent to Technical Advisory BoardComments expected by end of April
• Completed final draft reported by early May and provided to Board for May meetingPosted on CIWMB website by early May
• Peer-review and public comments through late May • Final report and responses to comments targeted for
completion by June for Board Review & approvalRelease of Final Report will be delayed to July
Board meeting if comments remain to be addressed
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Feedstocks for Alternative Feedstocks for Alternative Conversion TechnologiesConversion Technologies
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
MSW & Diversion in CaliforniaMSW & Diversion in California
• California landfills approximately 37.5 million tons of waste annually (U.S. 231.9 million tons annually)
• 1990 Integrated Waste Management Act (AB 939) set goals to cut waste disposal by 25 by 1995 and 50% by 2000
• Diversion Rates have increased considerably from 10% in 1989 to 47% currently
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
University of California, RiversideUniversity of California, Davis
Waste Distribution Waste Distribution Mass/EnergyMass/Energy
0
5
10
15
20
25
30
35
40
45
50
Paper
/Car
dboa
rdFoo
d
Leav
es a
nd G
rass
Other
Org
anics
C&D Lum
ber
All non
-Film
Plas
tic
Film P
lastic
Branc
hes a
nd st
umps
Textile
s
Fra
ctio
n o
f T
ota
l (%
)
Mass Basis Energy Basis
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Energy EquivalenceEnergy Equivalence
• 2370 MW of electrical power5% of states capacity and 6% of consumption
• 60 million barrels of crude oil@ $37 barrels ----- $2.2 billion
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Diversion Efforts for Misc. OrganicsDiversion Efforts for Misc. Organics
• 170 compost and Process facilities • Composting, mulch, landfill cover, biomass to
energy• Handle 6-7 million tons of organic materials• 2 million wet tons (1.6 MBDT) urban wood
waste consumed in several of the state’s 30 biomass power plants
• Approximately 15 million wet tons (~ 8 MBDT) of organics sent to landfill (C&D wood, green waste, food waste, and ‘other’)
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Diversion Efforts for PaperDiversion Efforts for Paper
• Paper recycling represents 4-5 million tons (30-35%)
• Cardboard boxes – recycle rate 52%• Old newspaper – recycle rate 59%• 10 million tons of paper to landfill• 25 million tons of organic materials still sent to
landfill
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Diversion Efforts for PlasticsDiversion Efforts for Plastics
• Overall recycling rates for plastics are relatively low and in the 2-4% recovery range
• PETE (soda bottle) recycling rates were over 70% in California in 1994 – up from 4% in 1988
• HDPE (milk jug) recycling rates were ~25% nationally
• Recycling rates for plastic films and other plastics which make up a predominant portion of the waste remain below 3%, however
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Waste ReductionWaste Reduction• Packaging and containers32% of MSW generated, 28% of disposed MSW
• European Policies1994 EC Directive to take measures to reduce
package waste1991 German Extended Producer ResponsibilityManufacturers take back container packagingIndividual companies or central systemUS$2.25 per monthPackaging 90% recovered and 80% recycled
• Uncertain how readily such programs could be implemented in California
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
MSW Combustion [aka incineration]MSW Combustion [aka incineration]• 130 million tons worldwide at over 600 facilitiesRoughly 75% of waste in Japan
• 167 large facilities in US ---- 2/3rds on east coast3 in California
• Poor perception by publicIncinerators have decreased emissions
considerably
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Feedstocks for Alternative Feedstocks for Alternative Conversion TechnologiesConversion Technologies
• Thermochemical processes can accept nearly all organics
• Biochemical processes generally accept only biodegradable feedstocks
Some ‘high solids’ reactors can accept more inhomogeneous waste – with the no biodegradable components exiting as digestate
• Effects of metals in pigments, etc.• PVC and chlorine containing materials can
contribute to dioxin/furan formation in thermochemical processes
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Waste Distribution Waste Distribution Mass/EnergyMass/Energy
0
5
10
15
20
25
30
35
40
45
50
Paper
/Car
dboa
rdFoo
d
Leav
es a
nd G
rass
Other
Org
anics
C&D Lum
ber
All non
-Film
Plas
tic
Film P
lastic
Branc
hes a
nd st
umps
Textile
s
Fra
ctio
n o
f T
ota
l (%
)
Mass Basis Energy Basis
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Biochemical Process FeedstocksBiochemical Process Feedstocks
• Biodegradable components of the landfill stream include:• Food wastes• Leaves, grass, trimmings • Paper/cardboard• Wood waste
• Biodegradation varies in rate and degree
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Biochemical Process FeedstocksBiochemical Process Feedstocks
• Biodegradation is not complete• Lignin fraction will not degrade
anaerobicallyLignin amounts:
• Wood (20-30%)• Food wastes (5-20%)• Paper (1 – 25%)
• Practical systems can not completely degrade the non-lignin components, due to time, volume, energy, and expense limitations
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Biochemical Process FeedstocksBiochemical Process Feedstocks
• Laboratory studies to determine Biomethane Potential (BMP)
• analogous to BOD assays for waste water
• Sample is digested under ideal AD conditions until no more biogas is produced (4-8 weeks)
Biogas Potentials
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Biochemical Process FeedstocksBiochemical Process Feedstocks
CH4 Generated (BTU/lb input)
Vegetable oil 16024Office paper 5609Corrugated paper 4389MSW C 2586MSW B 2466MSW D 2387Food waste 1969MSW A 1918Newspaper 1534Branches 1519Grass 1161Blend of grass, leaves, branches 1130Leaves 1123
Biomethane Potential (BMP) of some feedstocks
Energy in Biogas per wet pound of feedstock
Sources:Chynoweth, et.al., (1993)Owens and Chynoweth (1993)Eleaser, et.al., (1997)Tchobanoglous, et.al.., (1993)
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
LCA/ Marketing studyLCA/ Marketing study
• Examined impacts of alternative conversion technologies on recycling
• Most of results related to additional preprocessing needed for conversion technologies
• No effects on recycling of paper• Plastics recycling would increase for biochemical
processes
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
RecommendationsRecommendations
• Improve characterization of waste in conjunction with waste characterization studies
• Proximate, ultimate, and elemental analysisAsh, metals, toxic congeners
• Higher heating values (HHV)• Characterize protein, carbohydrates, and fats in
typical food wastes
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Alternative Conversion Alternative Conversion Technologies – Processes Technologies – Processes
and Productsand Products
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Conversion Processes to EvaluateConversion Processes to Evaluate
University of California, RiversideUniversity of California, Davis
Post recycled MSW
Option 1Send to Landfill
Option 2Send to CT
Pre-treatment (as required)
ThermochemicalConversion
BiochemicalConversion
Products:BiogasEthanol
Chemicals
Digestate (includes lignin)Post treatment
Residue
Digestate products:Fertilizer
Soil amendmentCompost
Direct use heat or power
generation
Producergas
Synthesisgas, and liquids
and solids
Products:Fuels
ChemicalsMaterials
Residue to landfill and/or waste water
treatment.Air emissions
Cogeneration of heat and
power
All Organics Biodegradable Organics
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
CombustionCombustion
• Full Oxidation of fuel for production of heat at elevated temps w/o generating commercially useful intermediate gases, liquids, or solids.
• Referred to as Incineration. • Flame temp: 1500 - 3000ºF• Heat & mass transport, progressive pyrolysis,
gasification, ignition, & burning, with fluid flow. • Usually employs excess oxidizer to ensure max.
fuel conversion• Recoverable Heat is only useful product.
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
PyrolysisPyrolysis• Thermally degrade material w/o the addition of any
air or oxygen• Similar to gasification – can be optimized for the
production of fuel liquids (pyrolysis oils), with fewer gaseous products (but leaves some carbon as char)
• Pyrolysis oil uses (after appropriate post treatment): liquid fuels, chemicals, adhesives, and other products.
• A number of processes directly combust pyrolysis gases, oils, and char
• Temp. range: 750-1500oF.
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
GasificationGasification• Emphasis is to form energetic gaseous
products with fewer liquids / solids residues
• Conversion via direct internal heating provided by partial oxidation using substoichiometric air or oxygen.
• Also indirect heating methods (externally fired burners) or autothermal methods (exothermic reducing reactions )
• Temp. Range: 1300 - 1500ºF.• Utilizes a reactant• Often used with pyrolysis to complete
gasification of pyrolytic oils and chars
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Process ParametersProcess Parameters• Product composition can be changed by temp, pressure,
speed of process, and rate of heat transfer. • Lower temp./fast pyrolysis temps -- more liquid products• High temperatures produce more gases• Higher pressures can increase reaction rates/ +scalability • Pyrolyzing/gasifying media can be varied by using
hydrogen and/or steam.• Hydrogen
Enhances chemical reduction processes Suppresses oxidation of carbon in feedstock Inhibits formation of dioxins and furans
• Water or steam Increase porosity of char-activated carbon (charcoal) Change the resultant gases and vapors. Can use lower temperatures but higher pressures than “dry”
processes.
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
SOLID FUEL(MSW, Biomass, etc)
GASIFIER
CYCLONE
GASCOOLER
FLY ASH
AIR, Steam, Pure oxygen, etc.
ASH ANDBED MATERIAL
CLEAN SYNTHESIS OR PRODUCER GAS
(FOR UTIILIZATION)
GAS CLEAN-UP
General Gasifier
Source: Carbona Coporation
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Gasification SchematicGasification Schematic
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
SOLID FUEL(MSW, Biomass, etc)
BED MATERIAL
GASIFIER
CYCLONE
GASCOOLER
WATERFROMHRSG
FLY ASH
AIR
GAS TURBINE
STACKFROM GAS
COOLER
TO GASCOOLER
STEAMTURBINE
CONDENSER
BOOSTERCOMPRESSOR
AIR
STEAM
ASH ANDBED MATERIAL
STEAM TOHRSG
CLEAN PRODUCT GAS
Turbine Exhaust
AIR
HEAT RECOVERYSTEAM GENERATOR
GAS CLEAN-UP
Gasifier (IGCC)
Source: Carbona Coporation
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Other example (BRI)
Patent 5,821,111 (1998) Bioengineering Resources, Inc.
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Gas-Phase ProductsGas-Phase Products• CO, H2, CH4, O2, N2, H20, CO2 + more minor species
• Majority of processes surveyed utilize post-combustion of gaseous for electricity/heat production
• Post combustion of gaseous products will produce products similar to those found in typical combustion (NOx, CO, hydrocarbons, etc.)
• Easier to clean than typical combustion Exhaust volumes are smaller (less/no O2/air) Pyrolysis oil formation – 80%, less than 20% gases Low molecular weight species (CH4 power plants,
CH4 or H2 engines) Cl, SO2, metals scrubbed prior to combustion
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Synthesis GasSynthesis Gas
• Mixture of CO and H2 that can be produced from a variety of sources
• The use of different reactants and process conditions in gasification allows the gas phase composition or the CO and H2 ratio to be varied
• Can be used to produce fuels, chemical products, feed gas for low temperature biochemical processes
• Direct process exhaust is essentially eliminated• Synthesis gas should be scrubbed prior to secondary
processing
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Catalytic CrackingCatalytic Cracking• Pyrolysis with catalytic cracking of oils • Utilized in oil refineries on polymeric wastes to
produce liquid fuels• Plastic Energy, LLC is siting a facility in California
using same technology as Zabrze, Poland facility (established in 1997)
• Ozmotech (Australia) installing similar facilities in Spain and Australia
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Catalytic CrackingCatalytic Cracking
• Planning to process waste plastics (numbers 2,4,5, and 6).
• ~95% will be film plastics (resins 2 and 4 or HDPE and LDPE)
• PVC and PET will be hand sorted at MRF
Plastic Energy LLC Facility
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Catalytic CrackingCatalytic Cracking
• Baled plastic delivered from MRF• Washed in mechanically stirred flotation tank (any
inadvertent PVC should sink)• Cleaned plastic is melted ~ 365 ºF
• Flows to reactor and introduced to catalyst, heated to ~600 ºF• Crude oil is formed which is distilled to gasoline and very
low sulfur diesel component • Gasoline used onsite for process energy, • Diesel product sold
Plastic Energy LLC Facility
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Catalytic CrackingCatalytic Cracking
Plastic Energy LLC Facility
Shred & clean plastic
Melt plastic
Reaction Distillation
Low Sulfur Diesel Product
Generator Electricity Gasoline
Baled Plastic
Gas Heat
Source: Larry Buckle Plastic Energy, LLC
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Catalytic CrackingCatalytic CrackingPlastic Energy LLC Facility
Product Mass (%)
Gallons/ton feedstock
Gallons/day (50 t/day)
Gallons/day (100
t/day)
Diesel 85 242 12,100 24,200
Gasoline 14 45 2,250 4,500
Light hydrocarbons
1 (vapor)
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Plasma Arc SystemsPlasma Arc Systems
• Heating Technique using electrical arc
• Developed for treating hazardous feedstocks
• Contaminated soils
• Low-level radioactive waste
• Medical waste
• Used in some metals processing
• Good for creating molten ash (slag), so is used for incinerator ash melting and stabilizing in Japan
• One Commercial scale facility for treating MSW in Japan
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Plasma Arc SystemsPlasma Arc Systems
• Can be used in pyrolysis, gasification, or combustion systems
– Depends on amount of reactive oxygen or hydrogen fed to reactor
• Air or inert gas is passed through electric arc creating ionized plasma
• The plasma can reach temperatures of 9,000 – 27,000ºF;
• Gas temperature in the reactor chamber (outside of the arc itself) can reach 1,700 – 2,200ºF; and
• The molten slag is typically around 3,000ºF.
• Will create producer/synthesis gas if operated as gasifier
• Plasma systems can require large amounts of electricity
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Plasma Arc SystemsPlasma Arc Systems
RCL Plasma – Recoverable Energy EstimatesNo air/oxygen used in gasifier
Units
Energy at exit of gasifier
Gas furnace (20% conversion
efficiency)
Reciprocating engine (35% conv. efficiency)
Gas turbine Combined Cycle
(45% conv. efficiency)
(MMBTU) 9726 1945 3237 4099
Less Electricity to power Torch (MMBTU) -1895 -1895 -1895
Electricity for Export (kWh)16 434 712
Net efficiency to electricity (%) 0.5 14.3 23.5
Power Export- (500t/day input) MWe 0.34 9 15
Electricity production Technology
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
University of California, RiversideUniversity of California, Davis
BRI Energy, LLC BRI Energy, LLC
• Yield from biomass feedstock is potentially greater than acid/enzymatic hydrolysis because lignin is converted in gasifier (Claim 75 gallons ethanol/dry ton)
• Because of bacteria and bioreactor characteristics, fermentation stage is quick
• Claim material is gasified and fermented to ethanol in less than 1 hour. (Std. sugar fermentation ~ 36-48 hrs.)
• Plastics, tires, waste oils can be processed to ethanol in this system
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
NovaholNovahol
• Also promoting ethanol from fermentation of synthesis gas
• Focusing on wood waste right now (wood from bark beetle infestation)
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Facilities with > 10% of feedstock coming from MSW components.
Many co-feed with animal manures, biosolids
~90% of capacity is composed of Single Stage systems
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Biochemical ConversionBiochemical ConversionCompany Name Corp. Headquarters
Process Name
Process TypeNumber of Facilities
Kompogas Glattbrugg, Switzerland Kompogas AD 25Valorga Montpellier, France Valorga AD 13Organic Waste Systems Gent, Belgium Dranco AD 13CiTec Finland/Sweden Waasa AD 11BTA (Canada Composting in North America)
Munich, Germany (Ontario, Canada)
BTA AD10
Wright Environmental Mngmt.
Ontario, Canada In vessel Composting 6Linde-KCA-Dresden Dresden, Germany AD & composting
(MBT) 3Eco Tec Finland WABIO AD 3Arkenol Ethanol via Acid
Hydrolysis 1Arrow Ecology Haifa, Israel Arrow Bio AD 1Wehrle Werk AG Emmendingen, Germany Biopercolat AD ?U-plus Umweltservice Ettlingen, Germany ISKA MBT / AD ?Onsite Power Systems Camarillo, CA APS (UC Davis) AD Pilot &
ProposedMasada Resource Group Birmingham, Alabama CES Oxynol Ethanol via Acid
HydrolysisPilot &
ProposedWTE (w/ Genahol) Santa Maria, CA Genahol/BEI Ethanol via Acid
Hydrolysis Proposed
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
• Technically viable for some components of waste stream
• Costs (and perhaps low public awareness) impede development
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Alternative Conversion Alternative Conversion Technologies – Technologies –
Environmental ImpactsEnvironmental Impacts
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Present SituationPresent Situation
• Landfills produce mainly CH4, CO2
• Trace gas constituents (BTX, H2S, vinyl chloride)
• Landfills largest source of GHG methane emissions --- roughly 1/3rd of total
• 3,000 landfills in California, 311 active• 51 convert gas to energy currently –211 MW• Another 26 planning to use energy – 29 MW• 70 landfills flare landfill gas (66 MW eq.)• Remainder (164) vent to atmosphere (31 MW
eq.)
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Thermochemical Process EmissionsThermochemical Process Emissions• Intermediate gases/oils may contain CO, VOCs,
HCl, H2S, dioxins/furans
• Many processes surveyed use intermediate gas combustion for electricity/heat production
• Post combustion of gaseous products will produce products similar to those found in typical combustion (NOx, CO, hydrocarbons, etc.)
• Easier to clean than typical combustion Intermediate gas volumes are smaller (less/no
O2/air) Low molecular weight species (CO, H2, CH4) Cl, S, PM can be scrubbed prior to combustion
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Dioxin/Furans IDioxin/Furans I
ClCl ClCl
ClClClCl
OO
OO
ClCl ClCl
ClClClCl OO
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Dioxin/Furans-Formation IIDioxin/Furans-Formation II
• Poor gas-phase mixing• Low combustion temperatures• Oxygen-starved conditions• Temperatures 480ºF to 1290ºF• Formation from Wastes
Feedstocks with high levels of Cl and CuOxygen content of feedstock 25-45%
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Notes: As=Arsenic, Cd = Cadmium, Cr=Chromium, Pb=Lead, Hg=Mercury, ND=not detect
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Solid Waste DataSolid Waste Data
Ash Residuals and Leaching Data for Various Pyrolysis/ Gasification Facilities/Technologies (mg/l unless noted) Units As Ba Cd CN Cr Cu Pb Mn Ni Hg Zn All
metals BalPac mg/l 0.05 0.37 0.1 0.01 0.58 Compact Power
risks• Proper design of waste conversion processes must
address air emissions, liquid and solid residues• Characterization and pre-sorting of feedstocks
can reduce emissions • Process and pollution control technologies can
minimize environmental impacts, but must be carefully designed and operated
• Overall environmental impacts of well-designed alternative waste conversion technologies are equal to or less than current practice of landfilling
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Conclusions for Alternative Conclusions for Alternative Conversion TechnologiesConversion Technologies
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Problem at Hand?Problem at Hand?
• Non-sustainable environment of landfilling of 37 million tons of material annually
• Landfill gas impacts & other factors
• Landfill expansion becoming more difficult and not beneficial to society
• Source reduction, recycling, alternative conversion technologies
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Available FeedstocksAvailable Feedstocks• 2370 MWe or 60 million barrels of oil• Paper and Cardboard
Landfill 10 million tons, Recycle 4-5 million tons (30%) 44% of energy value
• Plastics 2nd high energy content – 30% of total 11% of landfilled mass and 22% of landfilled volume Growing rapidly and recycling rates are relatively low Only thermochemical can process
• Contaminants Chlorine containing materials (PVC) Pigments in paper, other metal contaminants
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Thermochemical ProcessesThermochemical Processes• Pyrolysis - Thermally degrade material w/o the addition of any air or
oxygenCan be used to maximize oil productionMany processes use post-combustion for electricity
• Gasification - Conversion via direct internal heating provided by partial oxidation using substoichiometric air or oxygen (Hydrogen or steam)Indirect heating methods (externally fired burners) or autothermal methods
(exothermic reducing reactions )Can be utilized to produce synthesis gases
• Synthesis gas produce chemical/fuel without combustion• Combust for electricity -produce gaseous products similar to
combustionLower exhaust volumesLower molecular weight speciesScrubbing prior to full combustion or use in chemicals/fuels
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Thermochemical Processes IIThermochemical Processes II• Have the greatest potential to process the whole MSW
organic stream• More commercial in Japan and Europe• Some plants have experienced problems – Technology must
be proven sound• Study did not cover economic viability• Suggest AB2770 definition for gasification be modified to
be more scientifically correct• More formal vendor should be conducted • Need to consider possibility of fuels/chemical instead of
electricity – perhaps work in this directionSynthetic ethanol, F-T diesel, hydrogenEthylene, fertilizers, petroleum products, adhesivePyrolysis Oils – fragrances, adhesives, resins, Pharmaceuticals
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Biochemical ProcessesBiochemical Processes
•Fermentation, anaerobic & aerobic digestion
•Carried out at lower temps. & reaction rates
•Utilize biodegradable feedstocks
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Environmental ConclusionsEnvironmental Conclusions• Air Emissions – Thermochemical process
– Can use synthesis gas for fuel/chemical w/o combustion
– Post-combustion – similar products to combustion– Little for no oxygen/air – reducing environment– Small air volume– Low molecular weight species – cleaner to combust– Less costly but similar emissions control
• Solid Waste– Thermochemical processes concentrate but do not
create metallic species
• Liquid Waste– Spent acids from biochemical processes, spent
scrubber solutions
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
Socio-economic ImpactsSocio-economic Impacts
• Full Life Cycle Analysis should be used in comparing benefits/liabilities
• Potential Resource – 60 million barrels oil or 2370 MW electrical power
• Provide diversity of product markets
• Extension of landfills
• Impacts on recycling
• Environmental impacts
Center for Environmental Research and Technology
University of California, RiversideUniversity of California, Davis
RecommendationsRecommendations
• Formal vendor evaluation• Improve Characterization of MSW