Office of Research and DevelopmentNational Risk Management Research Laboratory, Land and Materials Management Division

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Gerardo J. Ruiz-Mercado (1), Ana Carvalho (2), and Heriberto Cabezas (1)

(1) National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH, USA(2) CEG-IST, Instituto Superior Tecnico, Universidade de Lisboa, Lisboa, Portugal

Using Green Chemistry and Engineering Principles to Design, Assess, and Retrofit Chemical Processes for Sustainability

7th International

Congress on

Sustainability Science &

Engineering

Cincinnati, OH, USA

Disclaimer

The views expressed in this presentation are

those of the author and do not necessarily

represent the views or policies of the U.S.

Environmental Protection Agency.

1

Outline

• Sustainability: Conceptual

• Process Design

• Sustainable Process Screening: WAR Algorithm

• Sustainable Process Assessment: GREENSCOPE

• Sustainable Process Retrofit: SustainPro

• Sustainable Process Design: Bringing it Together

2

Sustainability:

Conceptual

3

0

1000

2000

3000

4000

5000

6000

7000

8000

-5000 -4000 -3000 -2000 -1000 0 1000 2000 3000

Hu

man

Po

pu

lati

on

Year

Historical World Population(https://en.wikipedia.org/wiki/World_population)

4

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

-4500 -3500 -2500 -1500 -500 500 1500 2500

Real

GW

P

Year

Real Gross World Product(https://en.wikipedia.org/wiki/Gross_world_product)

($US billions, 1990 intl $US)

5

World Ecological Footprint &

World Biocapacity

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1961 1965 1970 1975 1980 1985 1990 1995 2000 2005 2007

Foo

tpri

nt

& B

ioca

pac

ity

(he

ctar

es)

Year

~1977

6

Total Ecological Footprint

Total Biocapacity

Source: National Footprint Accounts 2010 edition

www.footprintnetwork.org

Courtesy of M. Hopton, U.S. EPA

How does the biophysical

world work?(Mostly Closed to Mass & Open to Energy)

Earth:

life,

economy,

society,

technology,

etc.

Sun

Light

Energy

Dissipation

to Space

7

Process Design

8

Processes/Industrial

Manufacturing

9

Process SalesRaw

Materials

Capital

Energy

Products

Customers

ProfitsWaste

Mass

Waste

Energy

Sustainable Processes

10

IT HAS TO BE SYSTEMATIC SO THAT GOOD

OPTIONS DONOT GET OVERLOOKED!

1. There is a hierarchical scheme for sustainable

process design:

a. WAR Algorithm for initial screening and

analysis of new and existing designs.

b. GREENSCOPE for detailed process

analysis.

2. For established process designs, SustainPro

provides an effective algorithm for retrofitting

to make processes more sustainable.

Sustainable Process

Design: WAR Algorithm

11

Potential Environmental

Impact (I or PEI)

12

Chemical

Process

İout(w)

İgen

𝜓𝑙 = 𝛼𝑚𝜓𝑙𝑚

𝑚

𝐼 𝑘(𝑖)=

𝑑𝐼𝑘(𝑖)

𝑑𝑡=

𝑑𝑀𝑘(𝑖)

𝑑𝑡 𝑥𝑘𝑙𝜓𝑙

𝑙

Potential Environmental

Impact Balances

13

𝑑𝐼𝑆𝑦𝑠𝑡𝑒𝑚

𝑑𝑡=

𝑑𝐼𝑘(𝑓)

𝑑𝑡𝑘=𝑓

− 𝑑𝐼𝑘

(𝑝)

𝑑𝑡𝑘=𝑝

− 𝑑𝐼𝑘

(𝑤)

𝑑𝑡𝑘=𝑤

+𝑑𝐼𝑔𝑒𝑛

𝑑𝑡

𝑑𝐼𝑔𝑒𝑛

𝑑𝑡=

𝑑𝐼𝑘(𝑝)

𝑑𝑡𝑘=𝑝

+ 𝑑𝐼𝑘

(𝑤)

𝑑𝑡𝑘=𝑤

− 𝑑𝐼𝑘

(𝑓)

𝑑𝑡𝑘=𝑓

General Expression:

Steady State:

Design Criteria

14

𝑑𝐼𝑔𝑒𝑛

𝑑𝑡≤ 0

Either Consume PEI or Minimize PEI Generation:

Minimize the Output of PEI:

𝑑𝐼𝑘

(𝑝)

𝑑𝑡𝑘=𝑝

+ 𝑑𝐼𝑘

(𝑤)

𝑑𝑡𝑘=𝑤

≥ 0

Sustainable Process

Design: GREENSCOPE

15

Chemical Process Indicators

16

• Triple dimensions of sustainable development

–Environment, Society, Economy

–Corporate level indicators

–Assessment at corporate level

Economy

Society Environment

Sustainable

development

Eco-efficiency Socio- economic

Socio-ecology

Rele

ases

E

col. g

oods &

serv

ices

Revenues

Econ.

goods &

serv

ices

Releases

Ecol. goods & services

• Four areas for promoting & informing sustainability

• Environmental, Efficiency, Economics, Energy (4E’s)

• Decision-making at process design level

• Taxonomy of chemical process indicators for use in process design

GREENSCOPE Indicators

17

Environmental (66)

•Specifications of

process input material

(e.g., hazardous)

•Operating conditions

and process operation

failures (health and

safety hazards)

•Impact of components

utilized in the system

•Potential impact of

releases

•100% sust., best target,

no pollutants release, &

no hazardous material

use or generation

Efficiency (26)

•Quantities of inputs

required/product or a

specific process task

(e.g., separation)

•Mass transfer

operations, energy

demand, equipment size,

costs, raw materials,

releases

•Connect input/output

with product,

intermediate or

operation unit

•The reference states are

defined as mass fractions

0 x 1

Economic (33)

•A sustainable

economic outcome

must be achieved

•Based on profitability

criteria for projects

(process, operating

unit), may or may not

account for the time

value of money

•Some cost criteria

Indicators: capital &

manufacturing costs;

Input costs: raw

material cost; Output

costs: waste treatment

cost

Energy (14)

•Different

thermodynamic

properties used to

obtain energetic

sustainability scores

•Energy (caloric); exergy

(available); emergy

(embodied)

•Zero energy

consumption per unit of

product trend can be

best target

•Most of the worst cases

depend on the particular

process or process

equipment

GREENSCOPE

Sustainability Framework

18

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 current process or •

tracking modifications/designs of new (part of a) process

Actual-Worst

% Sustainabilty Score = 100%Best-Worst

Sustainability Assessment &

Design: GREENSCOPE Tool

19

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

Efficiency Indicator Results

20

Indicator Description Sust. (%)

2. AEi Atom economy 5.8

7. MIv

Value mass

intensity0

15. MRPMaterial recovery parameter

0

17. pROIM

Physical return on

investment99.4

23. Vwater,

tot.

Total water

consumption100

Environmental Indicator Results

21

Indicator Description Sust. (%)

1. Nhaz. mat.

Number of hazardous

materials input75

6. HHirritation

Health hazard,

irritation factor68.5

10. SHreac/dec I

Safety hazard, reaction

/ decomposition I88.3

22. EHbioacc.

Environmental hazard,

bioaccumulation (the

food chain or in soil)

89.3

43. EPEutrophication

potential100

Energy Indicator Results

22

Indicator Description Sust. (%)

2. RSEI

Specific energy

intensity98.9

6. E

Resource-energy

efficiency77.0

8. BFE

Breeding-energy

factor100.0

10. Extotal

Exergy

consumption0.0

14. BFEx

Breeding-exergy

factor36.1

Economic Indicator Results

23

Indicator Description Sust. (%)

1. NPV Net present value 45.9

8. PBP Payback Period 92.0

19. COM Manufacturing cost 68.0

23. CE, spec. Specific energy costs 63.1

33. Cpur. air

fract.

Fractional costs of

purifying air0.0

Process Retrofit:

SustainPro

24

Process Retrofit

25

Retrofit design has been defined by Guinand (2001) as

follows: “Process retrofitting is the redesign of an operating

chemical process to find new configuration and operating

parameters that will adapt the plant to changing conditions

to maintain its optimal performance.”

1- Identify process bottlenecks

2-Select the most relevant bottlenecks for

improvements

3- Suggest new design alternatives -eliminate

the bottlenecks

4- Assess and select new design

alternatives

Retrofit Generic Methodology

SustainPro- Retrofit Tool

26

Collect Data

STEP 1Simulators

Flowsheet Decomposition• OP and CP

STEP 2

Equipment flowsheet into operational flowdiagram

STEP 1.A

Flowsheet Decomposition• AP

STEP 2

Simulators Plant Data

Calculate Indicators

STEP 3

3.1 Mass/Energy indicators3.2 Sustainability Metrics

3.3 Safety Indices

Calculate Indicators

STEP 3

3.4 Operational Indicators3.5 Compound indicators

Indicator Sensitivity Analysis (ISA)

STEP 4

Sensitivity analysis operational parameters

STEP 5

Generate/Evaluate new design alternatives

STEP 6

Properties

WAR

Solvent Separation

Properties

Continuous & Batch

Batch

Tools

SustainPro

CAPEC Database

ICAS - ProPred

ICAS – WAR algorithm

Super Pro Designer

Gproms

Aspen Tech

Pro II

ICAS 11

HYSYS

ICAS - ProCamd

Thermodynamic insights

Lable

SustainPro- Retrofit Tool.

27

Continuous Process Batch Process

Closed-path Open-path Accumulation-path

Step 1- Data Collection

Step 2- Flowsheet Decomposition

OR

Simulators

EA EB EC1 2 3 4

5

OP1 OP2 OP3

1 2

3

4 5

6

78 9

10

SustainPro- Retrofit Tool:

Indicators

28

Indicator Description Definition

MVA Material Value Added MVA = MT*(Psale-Pcost)

EWC Energy & Waste Cost EWC = E PE Mi θi/(Σi Mi θi)

TVA Total Value Added TVA = MVA - EWC

RQ Reaction Quality RQ = RX θR/ (Σp Mp)

AF Accumulation Factor AF = Mi-cycle /(Σk-cycle Mk-cycle)

REF Reusable Energy Factor REF = Eused-cycle/ Eexit-cycle

DC Demand Cost DC = PutilityEopen-path

TDC Total Demand Cost TDC = Σ DCk

Step 3- Indicators Calculation

SustainPro- Retrofit

Tool: Algorithm

29

IndicatorsVariables (VI)

VI,1

VI,2

…

VI,N

ObjectiveFunction (VOF)

VOF,1

VOF,2

…

VOF,N

Indicators (I)

I1

I2

…

IN

Common Variables

•Sensitive

•Large Amount

Min Max Score

Vmin Vmin + Inc 1

Vmin + Inc Vmin + 2Inc 2

Vmin + 2Inc Vmin + 3Inc 3

Vmin + 3Inc Vmin + 4Inc 4

Vmin + 4Inc Vmax 5

Scores

EWC, REF, TDC

AF, DC

High PositiveValues

MVA, TVA

RQ

High NegativeValues

HIGHEST SCORES ARE THE TARGETS

Step 4- ISA Algorithm

SustainPro- Retrofit Tool:

Alternatives

30

Target Indicators (TI)

OP1

OP2

…

OPN

Variation5, 10, 15%

Variation5, 10, 15%

Variation5, 10, 15%

Variation5, 10, 15%

ImprovementTI X%

ImprovementTI X%

ImprovementTI X%

ImprovementTI X%

Purge

Improve Separation

Insert New Separation

Increase Conversion

New Solvent

Increase Conversion

Highest Improveme

nt

Recycle

Separation

Inc Conversion

Separation

Source

Separation

Reactor

Change

Insert New

Improve

Separation

Reactor

CP Flowrate

OP Flowrate Raw Material

Product

Inert

Sub-Product

Solvent

Reverse Approach

Thermodynamic Insights

ICAS

Step 5, 6- SA and Generation of

alternatives

Sustainable

Processes: Bringing

It All Together

31

Some Final Thoughts

• There is a hierarchical scheme for sustainable

process design of new designs:

• WAR Algorithm for initial screening analysis.

• GREENSCOPE for detailed process analysis.

• For established process designs, SustainPro

provides an effective algorithm for retrofitting

to make processes more sustainable.

• However, these tools do not and can not

substitute for the skill of the engineer. A fine

hammer is wonderful in the hands of a skilled

carpenter but useless in unskilled hands.32