chemical process indicators for sustainability assessment...

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

Chemical Process Indicators for Sustainability Assessment and Design

Gerardo J. Ruiz-Mercado, PhDU.S. Environmental Protection Agency

Office of Research & DevelopmentCincinnati, OH USA

National Academies of Sciences, Engineering and Medicine’s Roundtable on Science and Technology for Sustainability

November 12, 2015, Washington DC

• 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

Agenda

http://biconsortium.eu/sites/biconsortium.eu/files/pictures/Bio_Based_Basic_model.jpg

Sustainability and Chemical Processes

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

• 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• To evaluate & improve sustainability at early process design stages5

Green objectives• Green Chem. principles• Green Eng. principles

Chemical Process• Sustainability indicators• Dimensionless scale

Sustainability indicator results• Trends• Clear visualization

Potential sustainable

process

Qualitative ApproachesApply all of them?Levels of implementation?A “win-win” situation?Multiobjective function

Quantitative ApproachesIs this a sustainable process?How sustainable is it?Realistic limitationsScale for measuring sustainability

Sustainability CriteriaProcess areas for improvementsIdentification of key factors (SA)Multi-criteria decision makingOptimal tradeoff

Sustainable Process Design Procedure

• 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

Nonrenewable Resources

Env. & Ecological Processes

Dissipation & Impact Absorption

Renewable Resources Products

Releases

Chemical Process and Product Development

Sustainability Indicators

Economy

Society

Environment

Sustainable development

Eco-efficiency Socio- economic

Socio-ecology

Rel

ease

s

Ecol

. goo

ds &

ser

vice

s

Revenues

Econ

. goo

ds &

ser

vice

s

Releases

Ecol. goods & services

• 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

Chemical Process Indicators

Economy

Society

Environment

Sustainable development

Eco-efficiency Socio- economic

Socio-ecology

Rel

ease

s

Ecol

. goo

ds &

ser

vice

s

Revenues

Econ

. goo

ds &

ser

vice

s

Releases

Ecol. goods & services

• Triple dimensions of sustainable development– Environment, Society, Economy– Corporate level indicators– Assessment at corporate level

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

( )( )

×Actual-Worst

% Sustainabilty Score = 100%Best-Worst 10

• 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

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 potentialEHS hazard is released out of the process

11

Environmental Indicators: Example

( )× − •

•

=

−∆ ×=

∆

− ∆ + ∆ <=

2fire/explosion

4 4c,

fire/explosionproduct

flash

flash, flash

Probable energy potential for reaction with OSHMass of product

10SH

If is known0.005 1.0 if 0< 200

iIndVali i

i

i

H mm

TT T

IndVal ∆ ≤ ∆ ≥

= == = =

−

=

flash

flash

code

code

code

code

code

1 if 00 if 200

Elseif R is known1 if R 12,15,17,180.875 if R 11,300.75 if R 100 if R other

Elseif NFPA f is known1 if NFPA-flamm=40.833 if NFPA-fl

i

i

TT

IndVal

IndVal

amm=30.667 if NFPA-flamm=20.5 if NFPA-flamm=10 if NFPA-flamm=0

end

∆Hc: combustion enthalpy, kJ/kg∆Tflash: temperature difference between the standard flash point and process temperature, ℃Rcode: Risk phrases of European communityNFPA-f: flammability hazard class according to the U.S. National Fire Protection Agency (NFPA)

Safety hazard, fire explosion

Sustainability valueBest, 100% Worst, 0%

0 kJ/kgAll combustion enthalpy of each process substance is released

12

Efficiency Indicators

• 26 indicators

• Amount of materials and inputs required to generate thedesired product (reaction) or complete a specific processtask (e.g., separation)

• Mass transfer operations have implicit influence in theamount of energy demand, equipment size, costs, rawmaterials, releases, etc.

• Efficiency indicators connect material input/output with theproduct or intermediate generated in the process oroperating unit

13

Efficiency Indicators: Example

Actual atom economy Sustainability valueBest, 100% Worst, 0%

1 0( ) ( )( ) ( )

( )

( )

reagentreagents

productproduct

reag

Molecular weight stoichiometric coefficientMolecular weight stoichiometric coefficient

Mass of productTheoretical mass of product

MW

MW

ii

AAE AE

AE

mAAE

ε

ε

β

α

•

= ×

× =×

=

× ×=

×

∑

inlimit. reagent product

productent, 1 limit. reagent limit. reagent

MWMW

I

ii

m βα

•

=

× × ×∑

m•product: mass flow of product I , kg/h

m•inlimit. reagent: input mass flow rate of the limiting

reagent, kg/hMWi: molecular weight of the component i, kg/kmolαi: stoichiometric coefficient of the reagent iβ product: stoichiometric coefficient of the desired product

Value mass intensity

V

in,

1V

, product ,product 1

Total mass inputSales revenue or value added

I

m ii

m

I

m m i m ii

MI

mMI

S

S m C

•

=

•

=

=

=

= ×

∑

∑


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/yrSm: total income from all sales in year m, $ Cm, i: cost of material i in year m, $/kgm•

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: ExampleNet present value


NPV @ discount rate

(rd)= 0%

NPV @ rd= minimum

acceptable rate of return (MARR)=40%

for very high risk projects

n: life of the plant or equipment, yrPWFcf,m: the selected present worth factorSm: total income from all sales in year m, $COMm: cost of manufacture without depreciation, $FCIL : Fixed capital investment without including the land valuedm: 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 IRSrecm: 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, $

( )( ),1

,

, product ,product 1

The total of the present value of all cash flows minusthe present value of all capital investments

PWF 1 rec

PWF

n

cf m m m m m mm

n

v m mm b

I

m m i m ii

m

NPV

NPV S COM d d

TCI

S m C

COM

=

=−

•

=

=

= − − − Φ + +

−

= ×

=

∑

∑

∑( )

( )

, , , , ,

Land1

Land, ,

,1

, , ,

2

0.280 2.73 1.230.1

if rec =

0 if C

1.18

4.5 annual salary6.29 31.7 0

L m OL m UT m WT m RM m

m Ln

L mmm

m m L m mu

L TM BM ii

oBM i p i BM i

OL OL

OL

FCI C C C Cd FCI

C WC FCI d m n

m nTCI FCI WC

FCI C C

C C FC NN P

=

=

+ + + +=

+ + − = ≠

= + +

= =

== ×

= + +

∑

∑

( )0.5.23

Equipmentnp

np

NN = ∑

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 besttarget (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 corporatereports

17

Energy Indicators: ExampleExergy intensity


0 Max Extotal/kg product

( ) ( )( ) ( )

( ) ( )( )

• in

• in • •

input flows• •

in• in ch0 0

1 1 1

lost

pr uc

1

od t

Net exergy usedMass of productEx

Ex = Ex physical + Ex chemical+ Ex work + Ex heat

Ex = Ex l

E

n

x

Ex

Ex

J J c c

j i i i i ijj j i i j

k

R

R

m H T S n

m

x RT x x

W

• •

= = =

•

•

=

=

=

∆ − ∆ + +

−

+

∑ ∑ ∑ ∑

( )'

0 ,1 1

lost 0 generated'

in outgenerated

1 1 1 0

, , , , mix , , , , mix1 1

1 /

Ex =

K K

k kk k

J J Kk

j j j jj j k

c c

L j i j L ij L j V j i j V ij V ji i

Q T T

T SQS m S m ST

S x S S S y S S

•

•

• •∗

= =•

•• •

= = =

= =

+ −

= × ∆ − × ∆ −

∆ = ∆ + ∆ ∆ = ∆ + ∆

∑ ∑

∑ ∑ ∑

∑ ∑

b vf p, p,

b b

ln ln298K

LL V L

T H TS S C CT T

∆∆ = ∆ + − +

Entropy Value Component state

p, b

ln LL

TCT

Liquid stateTL

101.325 kPa

b vf p,

b

ln298KL V

T HS S CT

∆∆ = ∆ + −

v

b

HT

∆−

Liquid stateTb°

101.325 kPa

bf p, ln

298KL VT

S S C

∆ = ∆ +

bp, ln

298KVT

C

Gas stateTb°

101.325 kPa

fLS S∆ = ∆

fS∆

Gas state298 K,

101.325 kPa

Elemental reference state

Constituent elements

298 K, 101.325 kPa18

GREENSCOPE

GREENSCOPE Evaluation and Case Study

GREENSCOPE Tool: A Demonstration Case Study

20

•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

Classification lists, energy conversion factors,

potency factors

Physicochemical, thermodynamic, and

toxicological properties

Equipment, raw material, utility, and product costs, annual salary, land cost

GREENSCOPE

Energy (e.g., steam) Products

ReleasesRaw material (e.g., oil)

CHEMCAD Simulation

Energy & massEquipment

Operating conditionsProduct & releases

Experimental dataPredicted dataProcess data

Literature dataAssumptions

Tools/Simulation

All indicator results Satisfied?

Potential sustainable

process

YES

NO

Process designDecision-making

Experimental work Process modeling & optimization

New process design specifications

GRNS.xls Template

projectgreenscope.com

CHEMCAD Simulated Chemical Process File

21

Oil

22 FAME

NaOH Rem oval

3

20

16

9

25

2

NaOH

Air Rel.H2O

Glycerol

300

303

304

305

200

202

MeOH

T-101

T-102

T-103

R-101

R-102

P-101

P-102

P-103

P-104

H-101

H-102

S-101

S-102

W-101Waste Oil

128

203

11

17

10

31H20 & MeOH

302

301

5

8

13

H3PO418

14

23

201

4

6

26

204

INPUTS

OUTPUTS

• 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

Efficiency Indicator Results

Indicator DescriptionSust. (%)Pure Oil

Sust. (%)Waste

Oil2. AEi Atom economy 90.6 90.6

7. MIvValue mass intensity

99.5 99.1

15. MRP Material recovery parameter 16.7 70.0

17. pROIMPhysical return on investment

99.8 89.6

25. WI Water intensity 100 100

22

0.00

20.00

40.00

60.00

80.00

100.001. ε

2. AEi3. AAE

4. SF

5. RME

6. m mat tot

7. MIv

8. MI

9. MP

10. E

11. MLI

12. E mw13. EMY

14. CE15. MRP

16. f

17. pROI M

18. RI M

19. BF M

20. ω recycl mat

21. ω recycl Prod

22. ω recov prod

23. V water total

24. FWC

25. WI26. φ water type

Pure oilWaste oil 22

Environmental Indicator Results

23

0

20

40

60

80

1001. Nhaz. mat.

2. mhaz.

mat.3. mhaz. mat.

spec.4. mPBT mat.

5. CEI6. HHirritation

7. HHchronic toxicity8. SHmobility

9. SHfire/explosion

10. SHreac/dec I

11. SHreac/dec II

12. SHacute tox.

13. FTA

14. TRs

15. TR

16. EQ

17. EBcancer eff.

18. EHdegradation

19. EHair

20. EHwater

21. EHsolid

22. EHbioacc.

23. GWP

24. GWI

25. ODP26. ODI

27. PCOP28. PCOI

29. AP30. API

31. WPacid. water32. WPIacid. water33. WPbasi. water

34. WPIbasi. water

35. WPsalinity36. WPIsalinity

37. WPO2 dem.

38. WPIO2 dem.

39. WPtox. other

40. WPItox. other

41. WPtox. metal

42. WPItox. metal

43. EP

44. EPI

45. SMIM

46. MIM

47. ELR

48. EYR

49. ESI

50. BFM

51. RI

52. ms, tot.

53. ms, spec.

54. ms, recov.

55. ms, disp.

56. ws, recycl.

57. ws, nonrecycl.

58. ws, haz.

60. ms, haz. spec.

61. ms,nhaz.

62. ms, nhaz. spec.

63. Vl, tot.64. Vl, spec.

65. Vl, nonpoll66. Vl, poll.

59. ms, haz.

Indicator Description Sust. (%)

1. Nhaz. mat.Number of hazardous materials input 40.00

6. HHirritationHealth hazard, irritation factor 99.31

10. SHreac/dec ISafety hazard, reaction / decomposition I 97.00

22. EHbioacc.

Environmental hazard, bioaccumulation (the food chain or in soil)

98.34

27. PCOPPhotochemical oxidation (smog) potential

99.83

32. WPIacid. waterAquatic acidification intensity 99.88

38. WPIO2 dem.Aquatic oxygen demand intensity 0.60

43. EPEutrophication potential 98.89

23

Energy Indicator Results

24


2. RSEISpecific energy intensity

99.49

6. ηEResource-energy efficiency

63.26

8. BFEBreeding-energy factor

53.38

10. ExtotalExergy consumption

92.59

14. BFExBreeding-exergy factor

100.00

0

20

40

60

80

100 1. Etotal

2. RSEI

3. REI

4. WTE

5. SRE

6. ηE

7. RIE

8. BFE

9. Erecycl.

10. Extotal

11. REx

13. RIEx

14. BFEx

12. ηEx

24

Economic Indicator Results

25


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

17. EPC

0

20

40

60

80

1001. NPV 2. PVR

3. DPBP4. DCFROR

5. CCF

6. EP

7. ROI

8. PBP

9. TR

10. CCP

11. CCR

12. Rn

13. REV

14. REVeco-prod

15. Ceq16. TPC

18. CTM19. COM

20. CSRM

21. Cmat, tot.

22. CE, tot.

23. CE, spec.

24. CE, source

25. Cwater tot.

26. Cwater spec.

27. Cwater type

28. Cs tot.

29. Cs, spec.

30. Cl tot.

31. Cl, spec.

32. Cpur. air

33. Cpur. air fract.

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 assessmenttools for the simultaneous evaluation and optimizationof 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

28

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

References

29

Ruiz-Mercado, G. J.; Gonzalez, M. A.; Smith, R. L., Expanding GREENSCOPEbeyond the Gate: A Green Chemistry and Life-Cycle Perspective. CleanTech. & Env. Policy 2014, 16, (4), 703–713.

Ruiz-Mercado, G. J.; Gonzalez, M. A.; Smith, R. L., Sustainability Indicatorsfor 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 Indicatorsfor 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 Indicatorsfor Chemical Processes: I. Taxonomy. Ind. & Eng. Chem. Res. 2012, 51, (5),2309-2328.

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