Chemical Process Indicators for Sustainability
Assessment and Design
Gerardo J. Ruiz-Mercado, PhD
U.S. Environmental Protection Agency
Office of Research & Development
Cincinnati, OH USA
National Academies of Sciences, Engineering and Medicine’s Roundtable on
Science and Technology for Sustainability
November 12, 2015, Washington DC
The views expressed in this presentation are those of the author and do not represent the views
or policies of the U.S. Environmental Protection Agency
Agenda
•
Sustainability and Chemical Processes
•
Sustainability Indicators
•
GREENSCOPE Sustainability Evaluation Tool
•
GREENSCOPE Evaluation and Case Study
•
Challenges, Needs, and Opportunities to Advance Sustainability at
Process Level
2
Sustainability and Chemical
Processes
http://biconsortium.eu/sites/biconsortium.eu/files/pictures/Bio_Based_Basic_model.jpg
Sustainability for Chemical
Processes
Current environmental and social aspects that
may be affected by industry
• Renewable &/or bio-based products & feedstocks: meet
economic, social, and environmental benefits
Join efforts to incorporate sustainability principles
• Efficient renewable material transformation
• Less energy consumption and waste (nonhazardous) generation
• Clean processes, optimum social and economic benefits
• Life cycle assessment considerations
Sustainability from the lab to the manufacturing
plant
•Inexpensive starting materials
•High-yield and easy isolation of pure products
4
Quantitative Sustainability
Assessment
Green objectives
• Green Chem. principles
• Green Eng. principles
Qualitative Approaches
Apply all of them?
Levels of implementation?
A “win-win” situation?
Multiobjective function
Chemical Process
• Sustainability indicators
• Dimensionless scale
Sustainability indicator results
• Trends
• Clear visualization
Quantitative Approaches
Is this a sustainable
process?
How sustainable is it?
Realistic limitations
Scale for measuring
sustainability
Sustainability Criteria
Process areas for improvements
Identification of key factors (SA)
Multi-criteria decision making
Optimal tradeoff
Potential
sustainable
process
• NAS committee on incorporating sustainability in the U.S. EPA
– Integrate sustainability assessment and management into
management and policy decisions
– Assessments in terms of a trade-off and synergy analysis
• From qualitative to quantitative definitions
5
• To evaluate & improve sustainability at early process design stages
Sustainable Process Design
Procedure
Nonrenewable
Resources
Chemical Process and Product Development
Renewable
Resources
Env. &
Ecological
Processes
Products
Dissipation &
Impact Absorption
Releases
• Support decision-makers to determine whether a process
is becoming more or less sustainable
– Are we doing relatively good / bad?
• What benchmarks to use?
• How close are we to achieving absolute targets?
6
Sustainability Indicators
Releases
Ecol. goods & services
Society
Environment
Eco-efficiency
Socioeconomic
Economy
Econ. goods & services
Releases
Sustainable
development
Revenues
Ecol. goods & services
Socio-ecology
Chemical Process Indicators
Ecol. goods & services
Society
Environment
Sustainable
development
Eco-efficiency
Socioeconomic
Economy
Econ. goods & services
Ecol. goods & services
Socio-ecology
• Four areas for promoting & informing sustainability
– Integrated evaluation & decision-making @ design level
• Environmental, Efficiency, Economics, Energy (4E’s)
– Comprehensive and systems-based indicators for use in
process design
8
Revenues
– Environment, Society, Economy
– Corporate level indicators
– Assessment at corporate level
Releases
Releases
• Triple dimensions of sustainable
development
The GREENSCOPE Tool
• Clear, practical, and user-friendly approach
• Monitor and predict sustainability at any stage of process design
• Currently developed into a spreadsheet tool, capable of
calculating 139+ different indicators
• Stakeholders can choose which indicators to calculate
• Decision-makers can redefine absolute limits to fit circumstances
9
GREENSCOPE Sustainability
Framework
• Identification and selection of two reference states for each
sustainability indicator:
–
–
Best target: 100% of sustainability
Worst-case: 0% of sustainability
• Two scenarios for normalizing the indicators on a realistic
measurement scale
• Dimensionless scale for evaluating a current process or tracking
modifications/designs of a new (part of a) process
Actual-Worst )
(
% Sustainabilty Score =
× 100%
(Best-Worst )
10
Environmental Indicators
• 66 indicators
• Health & safety hazards: operating conditions and
operation failures
• Impact of components utilized in the system and releases
• Risk assessment & ecosystem services evaluation
• Integrated to life cycle assessment
• 100% sustainability, best target, is no releases of pollutants
and no hazardous material use or generation
• 0% sustainability, worst cases, all inputs are classified as
hazardous, and/or all generated waste for each potential
EHS hazard is released out of the process
11
Environmental Indicators: Example
Safety hazard, fire explosion
SHfire/explosion =
SHfire/explosion
Probable energy potential for reaction with O2
Mass of product
( −∆H
=
c,i
× 104×IndVal −4 ) mi•
i
•
mproduct
If ∆Tflash is known
−0.005∆Tflash,i + 1.0 if 0<∆Tflash < 200

if ∆Tflash ≤ 0
IndVali = 1
0
if ∆Tflash ≥ 200

Elseif Rcodeis known
1
0.875

IndVali = 
0.75
0
if Rcode = 12,15,17,18
if Rcode = 11,30
if Rcode = 10
if Rcode = other
Elseif NFPA − f is known
1
0.833

IndVali = 0.667
0.5

0
end
if NFPA-flamm=4
if NFPA-flamm=3
if NFPA-flamm=2
Sustainability value
Best, 100%
Worst, 0%
0 kJ/kg
All combustion enthalpy
of each process substance
is released
∆Hc: combustion enthalpy, kJ/kg
∆Tflash: temperature difference between
the standard flash point and process
temperature, ℃
Rcode: Risk phrases of European community
NFPA-f: flammability hazard class
according to the U.S. National Fire
Protection Agency (NFPA)
if NFPA-flamm=1
if NFPA-flamm=0
12
Efficiency Indicators
• 26 indicators
• Amount of materials and inputs required to generate the
desired product (reaction) or complete a specific process
task (e.g., separation)
• Mass transfer operations have implicit influence in the
amount of energy demand, equipment size, costs, raw
materials, releases, etc.
• Efficiency indicators connect material input/output with the
product or intermediate generated in the process or
operating unit
13
Efficiency Indicators: Example
Actual atom economy
AAE
= AE × ε
AEi =
∑
(Molecular weight ) × ( stoichiometric coefficient )  i
(Molecular weight ) × ( stoichiometric coefficient )  reagent
reagents
Mass of product
Theoretical mass of product
•
( β × MW )product × mproduct
AAE = I
• in
mlimit.
β
reagent
× product × MWproduct
(α × MW )reagent, i ×
∑
MWlimit. reagent α limit. reagent
i =1
ε=
Value mass intensity
Total mass input
Sales revenue or value added
MIV =
I
∑m
MIV =
=
Sm
i =1
I
• in
m ,i
Sm
∑m
i =1
•
m , product i
× C m ,product i
Sustainability value
Best, 100% Worst, 0%
1
0
m•product: mass flow of product I , kg/h
m•inlimit. reagent: input mass flow rate of the limiting
reagent, kg/h
MWi: molecular weight of the component i, kg/kmol
αi: stoichiometric coefficient of the reagent i
β product: stoichiometric coefficient of the desired product
Sustainability value
Best, 100% Worst, 0%
1
40
m•inm, i: input mass flow rate of the limiting reagent, kg/h
annual mass flow of substance i in year m, kg/yr
Sm: total income from all sales in year m, $
Cm, i: cost of material i in year m, $/kg
m•m, product, i: : annual mass flow of product i in year m,
kg/yr
14
Economic Indicators
• 33 indicators
• A sustainable economic outcome must be achieved for
any new process technology or modifications
• Based in profitability criteria for projects (process,
operating unit),
– May or may not account for the time value of money
– Benefit-cost analysis
• Indicators supported in cost criteria:
– Processing costs: capital cost, manufacturing cost
– Process input costs: raw material cost, utility costs
– Process output costs: waste treatment costs
15
Economic Indicators: Example
Net present value
NPV = The total of the present value of all cash flows minus
the present value of all capital investments
n
∑ PWF
NPV
cf ,m
m =1
n
∑ PWF
−
Sm
=
I
m= − b
∑m
i =1
( Sm − COMm − dm )(1 − Φ ) + rec m + dm 
•
m , product i
TCIm
v ,m
× C m ,product i
COMm = 0.280FCIL ,m + 2.73COL , m + 1.23 ( CUT , m + CWT , m + C RM , m )
dm = 0.1FCIL
C + WC + FCI − n d if m =
n
∑ m

L
recm =  Land
m =1

0
if m ≠ n
TCIm = CLand,m + FCIL ,m + WC m
u
1.18∑ C BM ,i
FCI
=L C=
TM
i =1
C BM ,i = C F
COL 4.5NOL × ( annual salary )
=
o
p ,i BM ,i
NOL =( 6.29 + 31.7P 2 + 0.23Nnp )
Nnp = ∑ Equipment
0.5
Sustainability value
Best, 100%
Worst, 0%
NPV @ rd=
minimum
NPV @
acceptable rate of
discount rate
return (MARR)=40%
(rd)= 0%
for very high risk
projects
n: life of the plant or equipment, yr
PWFcf,m: the selected present worth factor
Sm: total income from all sales in year m, $
COMm: cost of manufacture without depreciation, $
FCIL : Fixed capital investment without including the
land value
dm: depreciation charge. Here, it is assumed as 10% of
the FCIL evaluated in year m, however it can be
estimated by different methods
Φ: fixed income tax rate given by the IRS
recm: salvage-value recovered from the working capital,
land value, and the sale of physical assets evaluated at
the end of the plant life. Often this salvage value is
neglected, $
16
Energy Indicators
• 14 indicators
• Different thermodynamic assessments for obtaining an
energetic sustainability score
– Energy (caloric); exergy (available); emergy (ecosystem services)
• Zero energy consumption per unit of product is the best
target (more products per unit of consumed energy)
• Most of the worst cases do not have a predefined value
– They depend on the particular process or process equipment
– The designer has to choose which value is unacceptable
– Some worst cases can be assigned by taking the lowest scores
found through comparing several sustainability corporate
reports
17
Energy Indicators: Example
Exergy intensity
Entropy Value
Net exergy used
REx =
Mass of product
T 
 T   ∆H 
•
∆SL =
∆Sf + Cp, V ln  b  −  v + Cp, L ln  L 
Ex• in − Exlost
298K
T
b


 Tb 
REx =
•
mproduct
T 
• in
Cp, L ln  L 
Ex = Ex• (physical) + Ex• ( chemical)  input flows
 Tb 
+ Ex• ( work ) + Ex• (heat )
J
J
c
c
 Tb  ∆Hv
• in
• in
•
 ch



∆
=
∆
+
ln
S
S
C
Ex =∑ m j ( ∆H − T0 ∆S ) j + ∑ ∑ ni ∑ ( xiEx i + RT0 xi ln ( xi ) )

− 
f
p, V
L
 i 1 i =1
 j
 298K  Tb
=j 1
=j 1 =
K'
K
•
k
k 1=
k 1
=
+ ∑W + ∑ Qk• (1 − T0 / T∗ ,k )
−
•
•
Ex lost
= T0 Sgenerated
S=
∆=
SL , j
J
Qk•
× ∆S − ∑
T0
J'
K
• in
• out
generated
j
j
j
j
k 1
=j 1 =j 1 =
c
c
•
∑ m × ∆S − ∑ m
∑x
∆S + ∆S
∆=
S
∑y
i,j
L ,ij
L , j mix
V ,j
i 1 =i 1
i,j
∆SV ,ij + ∆SV , j mix
Sustainability value
Best, 100%
Worst, 0%
0
Max Extotal/kg product
Component state
Liquid state
TL
101.325 kPa
Liquid state
Tb°
101.325 kPa
∆Hv
Tb
Gas state
Tb°
101.325 kPa
 T 
∆SL =
∆Sf + Cp, V ln  b 
 298K 
 T 
Cp, V ln  b 
 298K 
Gas state
298 K,
101.325 kPa
∆SL =
∆Sf
∆Sf
Elemental
reference state
Constituent
elements
18
298 K, 101.325 kPa
GREENSCOPE Evaluation and
Case Study
GREENSCOPE
GREENSCOPE Tool: A
Demonstration Case Study
•Sustainability quantitative assessment
•Individual or multiple process comparisons: Waste cooking oil, USDA
model, Recycling unconverted oil, Hexane extraction
•Key factors, areas for improvements, optimal tradeoffs
New process design
specifications
Energy (e.g., steam)
CHEMCAD Simulation
Classification lists, energy
conversion factors,
potency factors
Energy & mass
Equipment
Operating conditions
Product & releases
Physicochemical,
thermodynamic, and
toxicological properties
Equipment, raw material,
utility, and product costs,
annual salary, land cost
Process design
Decision-making
Experimental
work Process
modeling &
optimization
Releases
Raw material (e.g., oil)
Experimental data
Predicted data
Process data
Literature data
Assumptions
Tools/Simulation
Products
NO
All indicator
results
Satisfied?
YES
Potential
sustainable
process
GREENSCOPE
projectgreenscope.com
GRNS.xls Template
20
CHEMCAD Simulated Chemical
Process File
•
•
•
•
Pure soybean oil
95% Oil conversion
1 Ton FAME/h
99.60% Purity
• 0.1 Ton Glycerol/h
• Utilities: steam, electricity,
cooling water
• Solid, liquid, & air releases
Air Rel.
H2O
305
203
I
N
P
U
T
S
300
25
Oil
FAME
22
T-102
H-101
P-103
6
2
200
8
26
P-101
Waste Oil
W-101
5
304
17
NaOH
303
S-102
202
NaOH Re m oval
4
13
R-101
S-101
11
14
3
MeOH
201
20
302
H-102
P-102
H20 & M e OH
T-101
31
1
23
R-102
28
16
T-103
10
O
U
T
P
U
T
S
9
Glycerol
H3PO4
P-104
204
18
301
21
Efficiency Indicator Results
26. φ water type 100.00
25. WI
1. ε
2. AEi
3. AAE
80.00
24. FWC
4. SF
60.00
23. V water total
5. RME
40.00
22. ω recov prod
6. m mat tot
7. MIv
15. MRP
0.00
20. ω recycl mat
8. MI
19. BF M
Description
Atom economy
Value mass
intensity
Material recovery
parameter
Sust. (%)
Waste
Oil
90.6
90.6
99.5
99.1
16.7
70.0
17. pROIM
Physical return on
investment
99.8
89.6
25. WI
Water intensity
100
100
9. MP
18. RI M
10. E
17. pROI M
11. MLI
16. f
12. E mw
15. MRP
22
2. AEi
7. MIv
20.00
21. ω recycl Prod
Indicator
Sust. (%)
Pure Oil
14. CE
Pure oil
Waste oil
13. EMY
22
Environmental Indicator Results
2. m
1. Nhaz. mat. haz.3. m
66. V
haz. mat.
65. Vl, nonpoll l, poll.
mat.
4. mPBT mat.
64. Vl, spec.
spec.
5. CEI
63. Vl, tot.
6. HHirritation
100
62. ms, nhaz. spec.
61. ms,nhaz.
60. ms, haz. spec.
7. HHchronic toxicity
80
Indicator
8. SHmobility
9. SHfire/explosion
59. ms, haz.
10. SHreac/dec I
58. ws, haz.
60
57. ws, nonrecycl.
1. Nhaz. mat.
11. SHreac/dec II
56. ws, recycl.
12. SHacute tox.
55. ms, disp.
40
54. ms, recov.
14. TRs
53. ms, spec.
16. EQ
51. RI
17. EBcancer eff.
0
50. BFM
10. SHreac/dec I
15. TR
20
52. ms, tot.
6. HHirritation
13. FTA
22. EHbioacc.
18. EHdegradation
49. ESI
19. EHair
48. EYR
27. PCOP
20. EHwater
47. ELR
21. EHsolid
46. MIM
22. EHbioacc.
45. SMIM
32. WPIacid. water
23. GWP
24. GWI
44. EPI
43. EP
38. WPIO2 dem.
25. ODP
42. WPItox. metal
26. ODI
41. WPtox. metal
27. PCOP
40. WPItox. other
39. WPtox. other
38. WPIO2 dem.
37. WPO2 dem.
36. WPIsalinity35. WP
43. EP
Description
Number of hazardous
materials input
Health hazard,
irritation factor
Safety hazard, reaction
/ decomposition I
Environmental hazard,
bioaccumulation (the
food chain or in soil)
Photochemical
oxidation (smog)
potential
Aquatic acidification
intensity
Aquatic oxygen
demand intensity
Eutrophication
potential
Sust. (%)
40.00
99.31
97.00
98.34
99.83
99.88
0.60
98.89
28. PCOI
29. AP
30. API
31. WPacid. water
32. WPIacid. water
33. WPbasi. water
34. WPIbasi. water
salinity
23
23
Energy Indicator Results
14. BFEx
100
1. Etotal
Indicator
2. RSEI
80
13. RIEx
2. RSEI
3. REI
60
6. ηE
40
12. ηEx
20
4. WTE
0
8. BFE
10. Extotal
11. REx
5. SRE
14. BFEx
Description
Specific energy
intensity
Resource-energy
efficiency
Breeding-energy
factor
Exergy
consumption
Breeding-exergy
factor
Sust. (%)
99.49
63.26
53.38
92.59
100.00
6. ηE
10. Extotal
7. RIE
9. Erecycl.
8. BFE
24
24
Economic Indicator Results
1. NPV 2. PVR
3. DPBP
4. DCFROR
33. Cpur. air fract.
32. Cpur. air
31. Cl, spec.
30. Cl tot.
100
80
5. CCF
60
29. Cs, spec.
28. Cs tot.
6. EP
7. ROI
40
27. Cwater type
26. Cwater spec.
Indicator
20
8. PBP
0
9. TR
25. Cwater tot.
Description
Sust. (%)
1. NPV
Net present value
44.52
8. PBP
Payback Period
81.10
19. COM
Manufacturing cost
68.70
23. CE, spec.
Specific energy costs
88.07
33. Cpur. air fract.
Fractional costs of
purifying air
85.26
10. CCP
24. CE, source
11. CCR
23. CE, spec.
12. Rn
22. CE, tot.
13. REV
21. Cmat, tot.
20. CSRM
19. COM
14. REVeco-prod
18. CTM 17. EPC
15. Ceq
16. TPC
25
25
Remaining Challenges to Advance
Sustainability at Process Level
•
•
•
•
Data availability for the calculation or prediction of sustainability using
indicators
– Chemical process heterogeneity
– New chemical compounds
• Physicochemical properties
• Toxicity properties and classification lists
– Cost
• Capital costs of unconventional equipment
• Time value variations
Quantitative social indicators
Multiproduct allocation for processes and facilities
– Mass, energy, value
Legal foundations and the establishment of official methodologies and
standards for the assessment of sustainability
26
Needs and opportunities related
to sustainability
•
•
•
To incorporate sustainability at the early stages of a project life and at the early
educational levels (New book Ruiz-Mercado and Cabezas (eds.), Elsevier)
– Sustainable chemical and products by design
– Dynamic systems
– Process control and optimization (Dr. F. Lima, WVU)
• process control with sustainability assessment
tools for the simultaneous evaluation and optimization
of process operations
– Multi-stakeholder decision-making (Dr. V. Zavala, U Wisconsin-Madison)
• Design and analysis of sustainable supply chains
To integrate life cycle considerations (assessment, inventory) at process
development level
Sustainability regulations at state, country, and international levels
– Not just greenhouse gases
27
Acknowledgments
 Dr. Michael A. Gonzalez, GREENSCOPE Co-developer
 Dr. Raymond L. Smith, GREENSCOPE Co-developer
 National Academies of Sciences, Engineering, and Medicine
 Dr. Jerry L. Miller, Director, Sci. & Tech. for Sustainability, NAS
28
References
 Ruiz-Mercado, G. J.; Gonzalez, M. A.; Smith, R. L., Expanding GREENSCOPE
beyond the Gate: A Green Chemistry and Life-Cycle Perspective. Clean
Tech. & Env. Policy 2014, 16, (4), 703–713.
 Ruiz-Mercado, G. J.; Gonzalez, M. A.; Smith, R. L., Sustainability Indicators
for Chemical Processes: III. Biodiesel Case Study. Ind. & Eng. Chem. Res.
2013, 52, (20), 6747–6760.
 Ruiz-Mercado, G. J.; Smith, R. L.; Gonzalez, M. A., Sustainability Indicators
for Chemical Processes: II. Data Needs. Ind. & Eng. Chem. Res. 2012, 51,
(5), 2329-2353.
 Ruiz-Mercado, G. J.; Smith, R. L.; Gonzalez, M. A., Sustainability Indicators
for Chemical Processes: I. Taxonomy. Ind. & Eng. Chem. Res. 2012, 51, (5),
2309-2328.
29
Thanks!
Questions?
[email protected]
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