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Class Project Report, May 2003
ME/ChE 449 Sustainable Air Quality
Causality of US Sulfur Production and Emission Trends
By
James Agan, Kate Miller, Cat Reid, Jason Reynolds
Instructor
Rudolf B. Husar
Washington University, St. Louis, MO
Sustainable Development (NAS)
•
A process of reconciling society’s developmental needs with the environmental
limits over the long term. It includes differing views on what should be developed,
what should be sustained and over what time period.
•
Human activities exert pressures, such as burning fossil fuels that alter the state of
environment, such air quality. The impaired environmental state, elicits responses,
such as regulations in a Pressure-State-Response (PSR) feedback loop system.
•
These three classes of variables can be measured using data that are collected for
administrative purposes. Combining these data with a simple but flexible scenario
captures a fundamental idea of sustainable development
•
•
The NAS (1999) describes SD as an uncertain and adaptive process, “in which
society's discovery of where it wants to go is intertwined with how it might try to
get there”. During the ‘journey’, the pathways of a transition to sustainability have
to be ‘navigated’ adaptively at many scales and in many places.
40%
30%
Trend of Indicators
1960s
20%
10%
0%
3
-10%
Pop
GDP/Pers
Bbtu)/GDP
Sox/Btu
SOX Emiss
-20%
1980s
-30%
2.5
-40%
40%
30%
1970s
20%
2
10%
0%
-10%
1.5
Pop
GDP/Pers
Bbtu)/GDP
Sox/Btu
-20%
-30%
1970s
-40%
40%
1
1980s
30%
20%
10%
0.5
0%
-10%
0
1900
SOX Emiss
Pop
GDP/Pers
Bbtu)/GDP
Sox/Btu
SOX Emiss
-20%
1920
1940
1960
1980
2000
2020
2040
GDP(Mill$)/Person
Energy(Bbtu)/GDP(Mill$)
SOx/Energy(Bbtu)
Population
SOX Emiss
-30%
1990s
-40%
40%
30%
1990s
20%
10%
0%
SOx = Pop x GDP/P x Btu/GDP x Sox/Btu
-10%
-20%
-30%
-40%
Pop
GDP/Pers
Bbtu)/GDP
Sox/Btu
SOX Emiss
US Population Trends
Millions
600
4.00%
500
3.00%
400
2.00%
1.00%
300
0.00%
1900
-1.00%
200
•
•
•
2000
2050
-2.00%
100
0
1900
1950
-3.00%
1950
2000
2050
Births
Deaths
Migration
In the 20th century, the US population has grown from 80 to 300 million
In As the birth and migration rates are greater than the death rate, the US population will continue to increase in the future
However, these rates are expected to stabilize over the next 50 years
– Birth rate ~ 1.5%/year
– Death rate ~ 1%/year
– Migration rate ~ 0.25%/year
Regional Population Projections
Regional Population Projections
Normalized Region 2 Population Projection
90000
1.6
80000
70000
60000
1.4
Population Change
Population (thousands)
1.5
50000
40000
30000
1.3
1.2
20000
1.1
10000
0
1995
2000
2005
2010
2015
2020
2025
1
1995
2000
2005
2010
2015
2020
Year
Year
Colorado
R1 - Pacific Coast
R2 - Mountain States
R3 - Southw est
R4 - Great Plains
R5 - Great Lakes
R6 - South
R7 - Northeast
R8 - Noncontinental US
*Regions split according to
geographic and state growth trends
Idaho
Montana
Nevada
Utah
Wyoming
2025
National Income by Industry Group/Person
12000
1.00
0.80
Income, $ (1996)
10000
8000
Res/com
0.60
Industrial
0.40
Transportation
0.20
0.00
1900
6000
Fraction of Total Income
1950
2000
2050
2100
2.5
4000
Trend by Ind. Group
2
1970 = 1
1.5
2000
1
0.5
0
1900
1950
2000
0
1900
2050 2000
1950
2050
2100
2100
The income of the res/comm sector has grown a the fastest rate, 10-fold since 1930, more than
doubling since 1970.
The industrial and transportation sectors have grown < 30% since the 1950s.
It appears that the industrial and transportation sectors will remain fairly steady over the next 20 years,
while the res/com curve will continue its rise before slowly leveling.
Sulfur Transfer by Fuels and Minerals: Theory
•
An understanding of the flow of sulfur is paramount in moving toward sustainability.
•
Know how much is produce, how much flows to the consumer, and how much makes it
to the receptors provides a way to monitor and catch the sulfur before it makes it into the
atmosphere, water, soil and etc.
Coal Production and S Content
• The high concentration of sulfur
is found in the eastern coal
mined in the US.
• Sulfur in Western coal is
generally < 1%
• Significant coal production is in
the west with a much lower
sulfur concentration, allowing
for less sulfur pollution without
decreasing consumption.
Coal Sulfur Flow in 1980 and 1998
Arrows indicate the flow of coal from the mines to the consumer
• In 1980, a major flow of sulfur
in coal originated in Illinois
and was transported to Florida
• By 1990, the transport of
high sulfur coal from the
Midwest has bee replaced
by low sulfur western coal
US Coal Production by Region
•
•
•
Coal production in the US occurred over five major producing regions.
The coal production over the eastern US has remained roughly constant throughout the century.
The sharp increase since the 1980s is due to the addition of western coal.
Trend of Average Coal S Content
• The average sulfur content of coal from each region is quite different; Eastern
coal is > 1%, western coal is ~0.5 %S.
• This average content has remained fairly constant for each region since it is
determined by geological factors.
• Therefore, the dip in the national average sulfur content must be a direct result
of the change in the source of sulfur, ie, more coal from the west is being used.
Capacity, Giga Watts
350
300
250
200
150
100
50
0
1900
FGD Capacity
•
•
•
•
1950
2000
Coal El. Util.Capacity
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
2050
Fraction
Flue Gas Desulfurisation (FGD) of El. Util. Coal
FGD Fraction
This figure shows the impact that FGD, (scrubbers) on coal fired power plant emissions
Since the 1970s when they were first used, scrubbers have steadily increased in capacity.
Currently (2000), scrubbers remove about 30% of the sulfur from the flue gases.
Hence, sulfur is being reduced both before (low sulfur coal) and after (scrubbing) the coal is
converted to energy.
Sulfur Recovery
•
•
•
Nature recycles the its sulfur, thus reaching a sustainable level for life.
Man has not reached a sustainable level for sulfur, because the amount
recovered has not been good in past years.
The amounts recovered has drastically changed over the year especially in
some sulfur producing processes moving us to sustainability.
Minerals Sulfur
Flow for Flow
Goods
Diagram (Tentative)
S Stocks
Exp/Imp Raw
Exp/Imp Proc
Metals, Frasch, Pyrites
Mineral Mining
S as Pollution
Production
Consumption
S as Goods
Exp/Imp Air
Ex/Im Water
Water
Fuel Mining
Fuels Flow for Energy
Coal, Oil, Gas
Land
Refining
Ex/Im Raw
Air
Combustion
Ex/Im Processed
Sulfur flows into the environment through (1) direct mining + byproduct of metals; (2) energy sources,
such as coal, oil and natural gas
Within these sources, there is some recycling and recovery of sulfur
Un-recovered sulfur is then released to the air, water, and soil environment as pollution
US Industrial Sulfur: Supply and Demand Trend
14
14
S Recovered
S Mined
12
12
10
10
8
8
6
6
4
4
2
2
0
1900
1950
2000
0
1900
2050
US S Supply
US Supply
Consumption
1950
2000
2050
US S Demand
US S Budget
Exp/Imp
12
S Stocks
Sulfur Stock
Stock Change
10
14
12
8
10
6
8
4
6
2
4
0
1900
-2
Exports
Imports
2
1950
2000
2050
0
1900
1950
Although the US was a leading source of mined sulfur, this industry has virtually disappeared
2000
2050
The use of recovered sulfur has negated much of the need for mined raw sulfur
The stocks of sulfur have decreased from about 4 Mtons in the 1930-70 period to virtually zero
Source http://minerals.usgs.gov/minerals/pubs/of01-006/sulfur.xls
However, the US consumption of sulfur exceeds that produced through environmental
recovery, so over the past 25
years, it has imported sulfur
Total S Mobilized and Recovered
14
14
Mobilized
in Fuels
10
8
6
4
6
4
0
1900
0
1900
2000
OilSMob
2050
Recovered from
Fuels & Min.
10
8
Frash S Mined
2050
MetalsSMob
S Recovered
TotMobilized
35
30
25
6
20
4
15
2
PetroleumSRec
2000
40
12
0
1900
1950
Pyrites S Mined
NGasSMobil
14
Million Tons/yr
8
2
CoalSMob
•
•
•
•
10
2
1950
Mobilized
in Minerals
12
Million Tons/yr
Million Tons/yr
12
10
1950
2000
NatGasSRec
2050
MetalSRec
5
0
1900
1950
2000
2050
Most of the S mobilization is driven by fuels, particularly coal (10-15 Mtons/yr)
Mined elemental sulfur peaked around 1970 but became insignificant by 2000
Recovered sulfur, especially from petroleum refining, has increased dramatically since 1950
The overall flow of mobilized sulfur has increased steadily until about 1970 followed by a downturn
Energy Consumption and Energy/$
Energy Consumprion per Sector
Energy/$ in Sector
50000000
Energy/$, Relative Trend since 1970
0.2
1.2
45000000
0.18
40000000
0.16
35000000
1
0.14
30000000
0.8
0.12
25000000
0.1
0.6
20000000
0.08
15000000
0.06
0.4
10000000
0.04
5000000
0.2
0.02
0
1900
1920
CE+RE
(Bbtu)
1940
1960
1980
IE (Bbtu)
2000
2020
2040
TE (BBtu)
0
1950
1970
CE+RE
(Bbtu)/$
TE (BBtu)/$
1990
2010
2030
2050
IE (Bbtu)/$
Tot Energy(Bbtu)/$
0
1950
1970
1990
2010
CE+RE
(Bbtu)/$,Norm
TE (BBtu)/$,Norm
2030
2050
IE (Bbtu)/$,Norm
Tot Energy(Bbtu)/$,Norm
Since 1950, the energy consumption has increased at similar rates in all sectors
Energy use/$ is the largest in the transportation and smallest in the ResComm sector
The energy use/$ of the industrial sector has not changed substantially since the 50s
Over the past 50 years, the the energy/$ of the entire economy has has improved by about
30%. The transition from ‘smokestack’ (industrial) to less energy-demanding ResComm
economy was a major factor.
SOx Emission Factor (SOx/Energy)
SOx/Enegy in Sector
SOx per sector
SOx/Enegy in Sector, Relative Trend Since 1970
20000
1
2
18000
0.9
1.8
16000
0.8
1.6
14000
0.7
1.4
12000
0.6
1.2
10000
0.5
1
8000
0.4
0.8
0.3
0.6
0.2
0.4
0.1
0.2
6000
4000
2000
0
1900
1920
1940
CommResTotal
1.
2.
3.
1960
1980
2000
IndRCTR
2020
2040
TE Total
0
1950
1970
1990
2010
2030
CommRes SOx/ComRes Energy
Ind SOx/Ind Energy
Transp Sox/ TranspEnegy
Sox/Energy, All Sectors
2050
0
1950
1970
1990
2010
2030
CommRes SOx/ComRes Energy
Ind SOx/Ind Energy
Transp Sox/ TranspEnegy
Sox/Energy, All Sectors
Up to the 1980s, the dominant emissions-sector was the Industry, but its emissions have declined rapidly
since about 1970. In fact, by 2000, ResComm emissions exceed the Industry values. Transportation is not a
significant SOx emitter.
The SOx emissions per energy use has steadily declined by a factor 2-3 in all sectors. The sharp decline in
the transportation SOx emissions in the 1950s is due to the transition from coal to diesel locomotives.
It is important to note that these indicators may not show the whole picture, as some of the Sox in each
sector is due to material flow rather than energy use, and the energy use can be direct or indirect (electric
utilities).
2050
SOx Emission Trend By Industry Group and by Fuel/Material
Emissions by Sector
35000
30000
25000
20000
15000
10000
5000
0
1900
ElUtil
1920
1940
Ind
1960
RecComm
1980
2000
Transport
2020
Metals
2040
Total
The total national SOx emission trend shows a see-saw pattern
over the past 60 years.
The peak in the 1940s was due to intense industrial and
res/comm activity. The peak emission of 30 million Tons/yr of
around 1970 was mainly due to electric utilities.
In fact, electric utilities, which tend to be coal-powered,
account for increasing fraction of the tional Sox emissions,
reaching 70% in the 1990s
The majority of emissions come
from coal use, which peaked in the
1970-90 period.
Oil products, metal smelting and
industrial chemicals were also
major contributors, but their
emissions have declined rapidly
since the 1970s.
Electric Utility & Metals Smelting
Electric Utilities
Metals Smelting
FUEL COMB. ELEC. UTIL.
6000
20000
5000
18000
SO2, 100 Tons/yr
16000
4000
14000
12000
3000
10000
2000
8000
6000
1000
4000
2000
0
1930
0
1930
1940
1950
1960
1970
1980
1990
2000
CoalTot
OilTot
GasTot
1950
1960
1970
1980
1990
2000
2010
2010
Metal
El. Util
1940
copper
lead
Ferrous Metals Processing
OtherTot
Looking closer at the electric utilities, we see that
the vast majority of emissions from electric
utilities are from the use of coal.
The recent decrease in Sox emissions from this
source is due mostly to switching to coal with a
lower average sulfur content (western coal).
Emissions from metals smelting has been
drastically reduced since 1970, even
more than the electric utilities.
This is primarily due to increased
recovery of sulfur from the smelting
process.
Industrial Fuel Combustion
Petroleum and Related Industries
PETROLEUM & RELATED INDUSTRIES
10000
1000
9000
900
8000
800
7000
700
SO2, 1000 Tons/yr
SO2, 1000 Tons/ye
FUEL COM B. INDUSTRIAL
6000
5000
4000
600
500
400
3000
300
2000
200
1000
100
0
1930
0
0
10
20
Industrial
30
CoalTot
40
50
OilTot
GasTot
60
70
OtherTot
In the industrial sector, emissions from direct energy use
tend to be dominated by emissions from coal.
This has decreased, in part because energy is
increasingly supplied by the electric utilities
1940
1950
Petroleum
1960
1970
1980
Petroleum Ref ineries & Related Industries
1990
2000
2010
other pretroleum
The petroleum industry in particular has been successful
in recovering sulfur from their material flows, and
thereby reducing emissions steadily.
1000
CHEMICAL & ALLIED PRODUCT MFG
900
1000
800
900
700
800
700
SO2, 1000 Tons/yr
600
500
400
300
600
500
400
300
200
200
100
100
0
1930
1940
OtherInd
1950
1960
1970
Wood, Pulp & Paper
1980
1990
cement mf g
2000
2010
0
1930
1940
1950
1960
1970
1980
1990
2000
Chemical
sulf ur compounds
Other Chemical Mf g
Agricultural Chemical Mf g
other
The contributions of material flows from other industries are significantly smaller (~1 MT/yr) than those
from energy use (~10 Mt/yr)
In general, these miscellaneous industrial emissions have been non-increasing.
2010
Commercial-Residential
6000
800
700
5000
600
4000
500
400
3000
300
2000
200
100
1000
0
1930
0
0
10
Other Fuel
20
ComCoal
30
40
CommOil
50
ResCoal
60
1940
1950
1960
1970
1980
1990
2000
2010
70
ResOil
In the commercial/residential sector, Sox emissions
from fuel use have declined significantly,
primarily due to the fact that most energy is
now supplied by the electric utilities.
Also, there was a switch from ‘dirty’ coal to cleaner
oil.
MiscArea
Other Combustion
Emissions from other miscellaneous
residential/commercial combustion and
processes were relatively small, and
have dropped to almost zero since
1980.
Transportation
On Road Transportation
Non-Road Transportation
1000
5000
900
4500
800
4000
700
3500
600
3000
500
2500
400
2000
300
1500
200
1000
100
0
1930
500
1940
1950
On Road
Light-Duty Gas Trucks
Diesels
1960
1970
1980
1990
2000
2010
Light-Duty Gas Vehicles & Motorcycles
Heavy-Duty Gas Vehicles
Road vehicles, contribute to Sox
emissions primarily through diesel
vehicles
However, by the 1990s, diesel
emissions have declined to level of
gas fueled vehicles.
0
1930
1940
NonRoad
1950
1960
Marine Vessels
1970
1980
Railroads
1990
2000
2010
Non-Road Diesel
The non-road Sox emissions came
historically from the use of coal in
railroads, and has decreased with their
fall from favor as a means of
transportation.
SOX Emission Factors for Industry Groups
-
With this detailed analysis, we can revisit trends in emissions factors
(Sox/energy) and summarize:
- The industrial and res/comm sectors both illustrate decreases in direct fuel use
and an increased use of electricity.
- The emissions factor for res/comm direct fuel use has decreased more
significantly because it is now dominated by oil use rather than coal (as in the
industrial sector).
- The overall emissions factor decrease, even with electricity added in, is
indicative of how the electric utilities have decreased emissions/energy by
switching to lower sulfur content coal. This can also be seen in the emissions
factors for fuels (left).
SOx Emissions: Where are We Heading and What Can I Do?
Heading Toward Sustainability
Some Regulations In place
Relative Emissions by Sector
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
1900
1920
1940
1960
1980
ElUtil
Ind
RecComm
2000
Transport
Electric energy consumption account for 70% national Sox emissions
Reducing electricity consumption is the most effective contribution to Sox pollution reduction
Over much of the country, air conditioning and appliances are the main consumers of
res/comm electric energy
2020
2040
Metals
Population - Energy/Goods Consumption– Materials Flow - Emissions
EconMeasure(EM)
Pop., P
Goods &Energy,(GE) i
Fuels&Mater.(FM), j
Emission (EM), k
Industr. Goods
Metals
SOx
Industrial Prod.
Industr. Energy
Ind. Chemicals
NOx
Transportation
Transp. Energy
Coal
HC
ResComercial
ResCom.Engy
Oil
PM
Electric Energy
Gas
Mercury
ai
bij
cjk
Consump./Person
Fuels/Energy
Emission/Fuel-
Ek = S
cjk EMj = S S bij cjk GEi = S S S ai bij cjk P
j
i j
i i j
Consumption of Goods and Energy:
Fuels and Materials Flow:
Emission of Pollutants:
GE = S ai P
FM = S S ai bij P
EM = S S S ai bij cjk P
The causal driver to pollutant emissions is the human population
 These emissions result from energy and material processes, which are driven by economic sectors
The causal factors of anthropogenic Sox emissions can be traced by this chart