life cycle-based air quality modelling for technology assessment and policy applications: the...

Life cycle-based air quality modelling for technology assessment and policy applications:

the concept and technical considerations

Weimin Jiang, Steven C. Smyth, Qiangliang Li

CMAS Conference, Chapel Hill 2Oct 16-18, 2006

Outline

• Introduction• Two current approaches in analysing air quality

impact of technologies• The concept of life cycle-based air quality

modelling (lcAQM) for technology assessment and policy applications

• Technical considerations for conducting lcAQM• Summary and discussions


Introduction

• A crucial and pressing issue facing human civilization:Rapidly expanding human material needs/desire

vs. Availability and sustainable use of natural resources

• The three pillars of sustainable development:Social, economic, and environmental

• Possible civilized solution:

New and emerging technologies, e.g., biofuels

• Key question: Which technologies are really “sustainable”?

• What can we (air quality modellers) contribute?Understand potential impact of the technologies on air quality

• Who need the answers?− Policy community − Industry − Anyone who breathes


• LCA = life cycle assessment

• Definition by ISO 14040:

“the compilation and evaluation of the inputs, outputs, and potential environmental impacts of a product system throughout its life cycle”

• Life cycle: from cradle to grave; individual stages or as a wholee.g. from biomass feedstock production to biofuel combustion

• ISO 14042: standard on life cycle impact assessment

• ISO 14042 GaBi (a LCA software)impact category photo-oxidant formation

category indicator tropospheric ozone formation

characterization factor photochemical ozone creation potential (POCP)

Current approach: LCA (1)

• Emissions and impact assessment are based on a functional unit:e.g., 1 vehicle-km travelled (VKT), 1 liter of fuel, 1 MJ energy, ...

Species

Emissions POCP Tropos. O3 formation

(g/VKT) (g C2H4-eq/g emis) (g C2H4-eq/VKT)

Diesel SD100 Diesel SD100

Carbon monoxide 1.14E+00 2.28E+00 2.70E-02 3.08E-02 6.16E-02

Nitrogen dioxide 5.31E-01 4.01E-01 2.80E-02 1.49E-02 1.12E-02

Nitrogen oxides 2.33E+00 2.60E+00 2.80E-02 6.53E-02 7.28E-02

Alkene (unspecified) 2.49E-05 8.90E-05 1.00E+00 2.49E-05 8.90E-05

Benzene 7.58E-05 5.41E-05 2.18E-01 1.65E-05 1.18E-05

Butane 7.29E-03 7.95E-04 3.52E-01 2.56E-03 2.80E-04

• • • • • • • • • • • • • • • • • •

Xylene 1.03E-04 3.67E-04 1.06E+00 1.09E-04 3.89E-04

VOC (unspecified) 2.03E-09 1.04E-04 1.13E-01 2.30E-10 1.18E-05

TOTAL 11.516 7.535 1.809 0.535

Current approach: LCA (2)


Current approach: 3-D AQM

• Use a 3-D air quality model, such as CMAQ, CAMx, CALGRID, ...

• Detailed atmospheric chemical and physical processes

• Spatially, temporally, and chemically resolved

• Technology scales considered

• Impact on atmospheric pollutant concentrations

• Most (if not all) focused on certain life cycle stage(s), e.g., emissions from vehicle engine combustion


The lcAQM concept

• lcAQM: life cycle-based Air Quality Modelling

– a natural advance of the current AQM practice with life cycle thinking

– integrate the LCA framework defined by ISO 14040 with the current AQM approach

• Example to illustrate the concept and considerations

The potential impact of large scale production and application of SunDiesel as a transportation fuel on air quality in Canada and the U.S. from a whole life cycle perspective. The results are to be used to support policy decisions regarding biofuel development.

An operational lcAQM framework

G o al d ef in it io n

S y s tem b o u n d ar y an d m o d ellin g s c en ar io d ef in it io n /d es ig n

E m is s io n s d a ta c o llec tio n ,es t im atio n , an d an a ly s is

3 - D a ir q u a lity m o d ellin g ,in c lu d in g in p u t f ile p r ep ar a tio n

Air q u a lity im p ac t an a ly s is : am b ien tp o llu tan t lev e ls , lo c a tio n , an d t im e

R es u lt in te r p r e ta t io n an d p r es en ta tio n

S en s it iv ity tes t : em is s io n s o f lif e c y c le s tag es

S en s it iv ity tes t : m o d ellin g s c en ar io d es ig n


Technical consideration: System boundary definition

• Chemical, physical, and engineering processes in different life cycle stages to be included in the analysis

• SunDiesel:

– Introduced by Choren Industries in Germany

– Can be used directly to replace petroleum diesel

– Made from cellulose, hemicellulose, and lignin, which are major components of a wide variety of biomasses

– Produced through two major chemical processes

• biomass gasification syngas (CO, H2, CO2, etc)

• Fisher-Tropsch synthesis: syngas SunDiesel


Life cycle of SunDieselas a transportation fuel

Bio m as s p r o d u c tio n

S u n D ies e l p r o d u c tio n

S u n D ies e l tr an s p o r ta tio n

S u n D ies e l s to r ag e

S u n D ies e ld is p en s in g

Veh ic le o p er a tio n


The biomass production stage

F er tilizer /h er b ic id e p r o d u c tio n an d tr an s p o r ta tio n

F er tilizer /h er b ic id e ap p lic a tio n

Bio m as s c u lt iv a tio n an d h ar v es tin g

Bio m as s tr an s p o r ta tio n

The SunDiesel production stage

Pyrolysis 400 -500 oC

Char

Tar-Rich Volatiles

O2

Ash

FT Reactor

Steam

Dust R

em

ove

r

H2O

HClH2SNH3

+H2O

Ash

Steam

Compressor

Washing Lye

KHCO3

Ultrafiltration

H2O

H2O

SundieselRecuperator

1500 oC

870 oC

200-240 oC

Scrubber II

Scrubber I Flash Gas

Gasifier

Electricity

Condenser

Electricity

H2O

Biomass

Regenerator

Steam

H2O

Air + CO2

Air

Gasification System

Clean System FT Reaction

Feeding System

Electricity

Steam

H2O

N2

Wax


SunDiesel production:an energy self-sufficient model

F eed s to c kp r ep ar a tio n

an d f eed in g

Bio m as sg as if ic a tio n

S y n g asc lean in g

F T S y n th es is

S teamg en er a tio n

P o w erg en er a tio n

O x y g eng en er a tio n

h ea t

f las h g as

s team

Bio m as s S u n D ies e l

e lec tr ic ity

o x y g enn itr o g en


Technical consideration: Modelling scenario definition/design (1)

• Possible locations and timing of industrial and agricultural operations in different life cycle stages

• Technology application scales and penetration levels

• Uncertainties in assumptions: sensitivity tests

• SunDiesel:

– Canada and continental US

– Full year of 2050: substantial displacement of petroleum oil by bio-fuels (?)


– Biomass-growing locations:

• Land-use coverage in Canada and US

• Forest logging site logging wood residues

• Agriculture and other suitable land energy crops

• Energy crop yields

• Conversion efficiencies of biomass SunDiesel

• Needs of food crops, animal feed, and energy crops

– SunDiesel production plant locations:

• Close to the biomass growth or collection sites

• Competing factors of plant sizes and distances from the biomass sites

Technical consideration: Modelling scenario definition/design (2)


Technical consideration: Emissions (1)

• Life cycle emissions data:

scarce, a major barrier, and require significant efforts

• Life cycle thinking in E.I. development:

– Cross-checking emissions between different life cycle stages

– Ensure completeness and self-consistency among life cycle stages

• E.I. used in AQM + LCI (life cycle inventory) used in LCA:

emissions data in GaBi, SimaPro, EcoInvent, etc.

• Spatial surrogate/ratios, temporal factors:

based on scenario definition/design assumptions and to be studied through sensitivity tests


• Removal of old-technology emissions:

analysis of SIC & SCC codes, and emis. source descriptions

• SunDiesel:

– Emissions from some life cycle stages can be assembled or derived:

• GaBi: Functional unit-based NOx, VOC, SO2, PM, and heavy metal emissions for various processes related to different fertilizers, fuels, and power

• Analysis of fertilizer and energy needs for biomass growth, and transportation, storage, and dispensing

• Speciated VOC emissions VOC speciation profiles for some life cycle stages

•



– Measured emissions from SunDiesel production not publicly available a major challenge for the SunDiesel lcAQM.

• Effort in estimating the emissions with great uncertainties

• Need emissions data: Choren or other FT processes, flash gas combustion

– Spatial surrogate ratios: reflect assumed spatial distributions of agricultural & industrial sources within life cycle stages

– Temporal factors: reflect seasonality of agriculture and industrial operational schedules

– Emissions from petroleum diesel life cycle: to be partially removed to reflect displacement of the fuel by SunDiesel



Technical consideration: Model implementation and result analysis

• Emissions grouped by major life cycle stages:

e.g., feedstock generation, fuel production, fuel transportation, storage, and dispensing, and fuel usage for transportation purposes, etc.

• Model runs with all the emissions, and sensitivity runs with or without emissions from certain life cycle stages

the air quality impact of individual life cycle stages or whole life cycle


Summary and discussions

• lcAQM = 3-D AQM practice with life cycle thinking for analysing technology impact on air quality.

• Special considerations:– System boundary definition: lcAQM foundation– Modelling scenario design: lcAQM foundation– Emissions data collection, estimation, and analysis:

• Data availability• Life cycle thinking in E.I. development for AQM• AQM E.I. + LCI• Spatial and temporal information associated with life cycle stages

– Model runs and analysis:• Based on the whole life cycle or individual life cycle stages


Acknowledgements

• Helmut Roth and Albert Chan, ICPET/NRC:

Review and comments

• Natural Resources Canada:

Funding for SunDiesel analysis

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