ceng2003 sd lecture2 print

Green chemistry

from end-of-pipe to clean production

© P. Lettieri

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Traditional solution: end-of-pipe techniques

� 'end-of-pipe' techniques are methods used to remove already formed contaminants from a stream of air, water, waste, product or similar. These are normally implemented as a last stage of a process before the stream is disposed of or delivered.

� Abatement of pollutants� Transformation into harmless products

� Transfer from one medium to another

� Examples�Removal of VOCs from offgas by combustion

� SO2 � CaSO4 � re-uses or landfill

�Wasterwater treatment � sludge

© P. Lettieri

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Why produce waste when alternatives are possible?

� Laws of environmental sanitation:“Once you get something dirty, the only way to get it

clean is to make something else dirty.”

� “The best way to keep the world clean is to avoid

getting it dirty to begin with.”

� and a new approach is born …

GREEN CHEMISTRY

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What is green chemistry ?

The design, commercialization and use of technically and economically feasible chemical processes and products

targeting the minimization of:

- the generation of pollution

- the risk for environment and health

� Complete re-thinking of current processes and products

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Important targets to prevention

Economical � reduce costs of treatment

� lower environmental taxes

� saving energy and water

Higher efficiency � more efficient use of feedstocks

� reduced production of (unwanted) by-products

Legal responsibility

� continued responsibility (even for yet unknown effects)

� more stringent standards

� how do pollutants behave ?

Eco-image � eco-friendly production is appreciated by public and customers

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Fundamental principles

� Prevent pollution

� Develop safe chemicals

� Develop clean methods of synthesis

� Use sustainable (re-usable) raw materials

� Improve catalysts to “direct” the reaction, thus reducing side-products

� Maximize the “economy of atoms”

� Use less solvents and improve conditions of the reaction

� Enhance energy-efficiency

� Develop chemicals and products which degrade after use

� Real-time analysis and process control

� Minimize risks of incidents

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Prevent pollution

� Better prevent from the start than clean afterwards!

� How?

�«Economy of atoms »

�Avoid by-products

�Improve catalysts (biocatalysis ?)

�Real-time analysis and control

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«Economy of atoms»

� Atom economy describes the conversion efficiency of a chemical process in terms of all atoms involved;

� In an ideal chemical process the amount of starting materials or reactants equals the amount of all products generated and no atom is wasted;

� Use all raw materials in the final product.

© P. Lettieri

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«Economy of atoms»

Simple example:CH4 + 1.5 O2 � CO2 + 2 H2O

If H2O = desired product, then the atom-economy (efficiency) is:

( )%56100

48412

1622 efficiency atom =⋅

++

+⋅=

%reactans all of weightMolecular

product desired of weightMolecular economy atom % 100×=

44% of materialis wasted!

© P. Lettieri

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� How much waste is produced in reality ?

Industry Annual Product Tons Kg waste / Kg product

Oil refining 106-108 0.1

Bulk Chemicals 104-106 <1-5

Fine Chemicals 102-104 5-50

Pharmaceuticals 10-103 25-100

© P. Lettieri

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Production of ibuprofenTraditional vs. Green

© P. Lettieri

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%401005.514

206100

reactants allFW

ibuprofenFW economy atom % =×=×=

Molecular weight of Total reagent used = 514.5Molecular weight utilized in Ibuprofen = 206Molecular weight non utilized in Ibuprofen = 308.5

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Molecular weight of Total reagent used = 266Molecular weight utilized in Ibuprofen = 206Molecular weight non utilized in Ibuprofen = 60

%77100266

206100

reactants allFW

ibuprofenFW economy atom % =×=×=

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Just for fun..

Feedstock for producing Viagra ©

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A complex chemical process

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An alternative simplification

� Reactive distillation of methylacetate

Reactor

SplitterExtractive

Distillaton

SolventRecovery

MethanolRecovery

Extractor

Azeo

Column

Decanter

FlashColumn

ColorColumn

FlashColumn

Water

Water

Heavies

MethylAcetate

Water

Catalyst

Methanol

Acetic Acid

ReactorColumn

ImpurityRemovalColumns

Water

Heavies

Acetic Acid

Methanol

SulfuricAcid

MethylAcetate

© P. Lettieri

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Sustainable Process Design

© P. Lettieri

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� The design stages of product development have a direct influence over about 70% of the final product – this brings with it “responsibility”…

� Designers play an important role because they are the industry’s connection with the marketplace, interacting between people and products.

Sustainable Process Design

5% Product design

15% Labour

30% Overhead

COST %

Who Casts The BiggestShadow ?

INF

LU

EN

CE

%

70%

20%

5%5%

50% Material

© P. Lettieri

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The Resource Cycle

materialsmaterials

extraction and processing waste

product waste

residuals

End-of-life goods

reuse

natural resource

primary material

goods

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� Environmental impact occurs at every stage of the life cycle

� Different products have different impacts at different stages…

� E.g. furniture = raw materials

� E.g. household appliances = use; energy consumption

� Impacts are often ‘locked in’ at the design stage when decisions about materials, function, performance, energy source, aesthetic, purpose etc. are made

� Only careful consideration at these early stages can make sure that negative effects excluded and positive features are included.

� Trying to retro fit solutions is often very costly – involving additional equipment, rather than solving the problem from first principles.

Why focus on design

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Good design will ensure that...

� a product contains a rationalised number of materials and components

� consumer health and safety issues are considered

� a product functions appropriately and effectively and communicates this function clearly

� a product is ‘styled’ appropriately

� a product is ergonomically correct

� environmental legislation requirements are addressed

© P. Lettieri

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Green design of products

� What is Green Design:

� can be considered to be design which takes into consideration only one element of environmental design;

� for example a product which uses recycled material, can be considered to be green design.

Dunlop recycled Wellington boots

© P. Lettieri

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Ecodesign looks further...

addresses all environmental impacts of a product throughout the complete lifecycle whilst maintaining other criteria

(such as cost, quality and appearance):

� Materials amount and type (appropriateness)

� Energy source and requirements

� Length of life

� Waste issues

� End of life issues

� Packaging issues

© P. Lettieri

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Key Ecodesign considerations

� Use less material

� Use materials with less environmental impact

� Use fewer resources

� Produce less pollution and waste

� Reduce the impacts of distribution

� Optimise functionality and service life

� Make re-use and recycling easier

� Reduce the environmental impact of disposal

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Examples of ecodesign productsKodak single use camera

Materials

� Fewer material types

� Plastics labelled for recycling

End of Life

� Collection system for old products to feed into remanufacture

� Testing and reuse of components

� Testing and reuse of batteries, or donated

� Plastic cases reground and fed into manufacture

© P. Lettieri

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� 1996, the Australian company, Kambrook, worked with the Royal Melbourne Institute of Technology to reduce the energy of the kettle.

� Their observations revealed that the kettle was often overfilled and reboiled as the user left the room to do something else.

� By designing around this behaviour the energy efficiency of the product was increased dramatically:

� Clear indicators – to stop overfilling

� Double insulation layer – to minimise need for

reboiling

� Temperature gauge to indicate the suitability

of the water for making tea or coffee and

to minimise need for reboiling

Kambrook’s AXIS kettle –

Energy reduction during use

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� Green design is limited to tackling one element of the lifecycle or environmental problem.

� Ecodesign, design for the environment or lifecycle design aims to reduce environmental burdens across the entire lifecycle.

� Sustainable (product) Design favours the lifecycle, just as ecodesign does, but places considerable emphasis on the additional inclusion of social and ethical considerations necessary to achieve sustainable development.

� Sustainable Design also has a highly prominent long- term timecomponent, in line with the concept of inter-generational equity inherent in sustainable development.

Moving to Sustainable Design

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product focus

systems focus

single issue focus

lifecycle approach

sustainability constraints

time component

Green Design

Ecodesign

Sustainable Design

� Green design and ecodesign have no manifest time dimension.

� Sustainable design is systems focused, where green and ecodesign have a product focus.

From Green Design to Sustainable Design

© P. Lettieri

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Sustainable Design

� Think about elements of good design

PLUS

� Add in elements of Ecodesign

� Think about eco-efficiency principles (“doing more with less”)

PLUS

� Add in Social considerations

� Long term effects

© P. Lettieri

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Social Side of Sustainable Design

� What needs does it meet

� What impact does it have on society

� Does it have a long-term impact on future generations

� Does making and using this product create jobs/opportunities

� Is it fairly traded

� Etc, etc

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System(process operation)

The system approach and system boundary assumed in conventional process design

INPUTS

Materials

Energy

OUTPUTS

Emissionswastes

Products

System boundary

� Traditionally, the system boundary is drawn around the process itself, usually without considering any upstream or downstream activities;

� It optimizes the performance inside the system boundary but is not optimal outside.

© P. Lettieri

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Process design for sustainability:the extended system boundary encompassing the life cycles of process and product

Extraction andmanufacture ofraw materials

Extraction of fuelsand energygeneration

Plantconstruction

Plantoperation

Plantdecommissioning

Product useEmissions and

wastemanagement

SYSTEM

© P. Lettieri

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Processdesign for

Sustainability

Technicalcriteria

Economiccriteria

Socialcriteria

Environmentalcriteria

Criteria considered in process design for sustainability

© P. Lettieri

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Process design for sustainability

� Approaches to design vary and no two designers will design a complex process following exactly the same steps.

� Regardless of the approach, design usually involves:

1. Project initiation

2. Preliminary design

3. Detailed design; and

4. Final design

� Each of these four stages consists of a number of steps.

© P. Lettieri

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Stages in process design for sustainability

1. Process initiation1. Identifying the need2. Initial identification of stakeholders and

sustainability design criteria3. Identifying the alternatives

© P. Lettieri

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1. Identifying the need

� All engineering projects are initiated as a result of an identified need or economic opportunity.

� In the context of sustainable development, this need must be fulfilled in a socially and environmentally responsible way while providing economic benefits.

� The designer is confronted with the sustainability challenge at the outset of the project and success will depend on:

� “external factors” such as: physical and thermodynamic laws limiting the process efficiencies and hence the level of sustainability.

� other “internal” factors such as the choice of process and operating conditions will be instead under the control of the designer.

1.Project initiation

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2. Initial identification of stakeholders

� Designers have to be aware of the relevant groups of stakeholders associated with the development and the sustainability issues that will be important for them.

� Typically, the stakeholders will include:

� Employees of the company

� Investors

� Neighbouring communities and citizens

� Non Governmental Organizations (NGOs)

� Government

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Why engage with stakeholders?

� Sustainable economic development cannot be

achieved without it

� The community has a right to be involved in

decisions that affect them

� Helps to avoid conflict and direct action

� Secure the development without excessive cost and time delay

� Local authorities/Government expect it

© P. Lettieri

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The nature of consultation

� Consultation is not

just about telling

people what you are

doing

� It has become

engrained in the

political process

� It is about winning or

losing support

Winning hearts and changing

minds:

the business of:

communicating

complex and

sensitive messages

to a diverse

stakeholder mix

© P. Lettieri

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A brief history of consultation

� 15 years ago only the enlightened bothered

� Seen as an unnecessary expense

� Planning & Compulsory Purchase Act 2004

� Proper stakeholder consultation is close to being compulsory

� Organised opposition groups - anti-Tesco; Roadblock etc (internet and speed of news flow)

� Major schemes have been delayed

� Poor consultation and abuse of data/manipulation of research is not tolerated anymore

© P. Lettieri

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You are dealing with …fear

� Property prices

� Disruption

� Noise

� Traffic

� Smell

� Health

� Loss of visual amenity

� Nimbyism

This can all add up to

a very big...

NO!

© P. Lettieri

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What are the positives

� Explain the benefits

� Counter the myth and

inaccuracy

� Put it into local

context

� Demonstrate best

practice

� Pledges of

responsible delivery

This can all add up to:

I need to

think

about this

© P. Lettieri

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Keys to effective communication with the stakeholders

� Understand that the community are not experts

� Set clear objectives/vision, Map the stakeholders

� Create success measures

� Get in early: Earlier planning starts the better, earlier education on the process starts the better

� Set the rules: clearly map Terms of Reference – from the start to the end of responsibilities; have processes in place for dealing with disputes

� Create Internal Communications Protocols that include the Community Group and other Stakeholders

� Provide data and evidence

� Work with the local media

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2. Sustainability design criteria, in addition to technical variables:

Economic Criteria Environmental criteria

Social criteria

Micro-economic:Capital costs

Operating costs

Profitability

Decommissioning

Macro-economicValue-added

Green taxes (e.g. carbon tax)

Investment (e.g. pollution

prevention; health and safety; decommissioning) Potential costs of environmental liability

Energy use

Water use

Water discharge

Solid waste

Global warming

Ozone depletion

Acidification

Summer smog

Eutrophication

Human toxicity

Eco-toxicity

Provision of employment

Employee health and safety

Customer health and safety

Nuisance (odour, noise,

visual impact and transport)

Public acceptability


© P. Lettieri

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3. Identifying the Alternatives

� There will be a number of alternative solutions to the design problem.

� These will include alternative processing routes, technologies, raw materials, energy sources, etc.

� The sustainable criteria are then used to evaluate the alternatives by identifying their advantages and disadvantages.

� At this stage, the initial screening is done on a qualitative basis and with discussions with the interested stakeholders.

© P. Lettieri

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1. Process initiation1. Identifying the need2. Initial identification of stakeholders and

sustainability design criteria3. Identifying the alternatives

2. Preliminary design1. Process selection and description2. Site selection3. Flowsheet preparation

- specification of equipment

- material and energy balances

4. Preliminary cost estimates5. Preliminary assessment of sustainability

criteria

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2.Preliminary Design

5. Preliminary Assessment of Sustainability and Further Identification of Sustainability Criteria

� Assessing economic sustainability of a process

� Economic evaluation based on micro-indicators for the whole life of the plant (25-30 years), (Conventional design).

� Sustainable design includes economic macro-indicators

plus environmental and social considerations.

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� Assessing environmental sustainability of a process

� Via two quantitative indicators:

� Environmental burdens:

�Materials and energy

� Emissions to air and water

� Amount of solid waste

� Environmental impacts:

� Life Cycle Assessment (LCA)

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� Assessing social sustainability of a process

� Via quantitative and qualitative indicators:

� Provision of employment (number of employees)

�Heath and safety issues (number of injuries)

�Occupational exposure Limits (OEL), fire explosions

� Visual impact of the plant

� Public acceptability

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3. Detailed Design1. Detailed equipment design2. Detailed economic analysis

- Capital costs

- Manufacturing costs

- Profitability analysis

3. Energy integration4. Process control and instrumentation5. Safety, loss prevention and hazard

and operability (HAZOP)6. Full assessment of sustainability7. Optimization of economic,

environmental and social sustainability


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3.Detailed Design

6. Full Assessment of sustainability

� Review of the sustainability criteria, normally not much more work involved from preliminary assessment

7. Optimization of economic, environmental and social sustainability

� In conventional design this would focus on optimizing costs and maximise profit;

� In design for sustainability it is also about minimizing environmental burdens and impacts;

�mathematical challenging involving development of procedures for solving multi-objective optimization problems.

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4. Final design1. Equipment drawing and layout2. Piping instrumentation3. Civil and electrical work, etc.

Planningapplication


Construction

Operation

Decommissioning

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