34th IAEE International Conference.
This presentation is the property of its rightful owner.
Sponsored Links
1 / 31

Carlos E. Escobar Toledo*, Lol-chen Alegría*, Bárbara Ramírez* PowerPoint PPT Presentation


  • 87 Views
  • Uploaded on
  • Presentation posted in: General

34th IAEE International Conference. Institutions, Efficiency and Evolving Energy Technologies Stockholm, June 19 - 23, 2011. ON EXERGY AND SUSTAINABLE DEVELOPMENT: SOME METHODS TO EVALUATE ENERGY EFFICIENCY AND NON-RENEWABLE RESOURCES WASTE WHEN USING SOME PLASTICS.

Download Presentation

Carlos E. Escobar Toledo*, Lol-chen Alegría*, Bárbara Ramírez*

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Carlos e escobar toledo lol chen alegr a b rbara ram rez

34th IAEE International Conference.

Institutions,Efficiency and Evolving Energy TechnologiesStockholm, June 19 - 23, 2011

ON EXERGY AND SUSTAINABLE DEVELOPMENT: SOME METHODS TO EVALUATE ENERGY EFFICIENCY AND NON-RENEWABLE RESOURCES WASTE WHEN USING SOME PLASTICS.

Carlos E. Escobar Toledo*, Lol-chen Alegría*, Bárbara Ramírez*

Departamento de Ingeniería Química.

Facultad de Química

Universidad Nacional Autónoma de México

*We thank to PAPIIT project number IN102710.


Abstract

ABSTRACT

  • This paper explores the role of energy utilization in sustainable development and the potential sources to increase energy efficiency*.

  • It also deals with the exergy analysis of plastic materials used for the manufacture of a lot of stuff used in our day-to-day life.

*This work follows Dewulf J. (2004)’ same concerns


Abstract1

ABSTRACT

  • Results of some plastics- short life uses, are presented considering the proposed methodology and the utilization of Multicriteria decision making to decide among possible substitutes more exergy and energy effective.


Framework

FRAMEWORK

From scientific point of view, it deals with exergy analysis of plastic materials used for the manufacture of some stuffs along its life cycle, including all the manufacture chains.

  • The same analysis is applied for other products can be used to substitute those materials.


Framework1

FRAMEWORK

  • For decision making aid, multi-criteria analysis is used for each alternative/case during the total life cycle (LCA); the criteria are: the Exergy loss (Irreversibility) (1), together with real quantity of energy used in the manufacture processes (2), the material balance including the quantity of resources, renewable or not, (3), emissions of Greenhouse gases in the life cycle (4) and an economic measure (5).


Objectives

OBJECTIVES

  • The main hypothesis is that the efficient use of energy, to avoid energy and raw material waste, are essential for long-term global sustainability.

  • With this framework, plastic disposable grocery bags and bottles for individual use, are analyzed to asses if those items are efficient on the energy efficiency viewpoint, considering also pollution and waste problems, within their full life cycle.

  • During production of those items, a waste of non renewable resources and Green House Gas (GHG) emissions are present.

  • There are also different materials or ways to use plastics getting longer use life cycle, saving energy and avoiding pollution, using technology-driven sustainability without wasting non renewable resources and energy.


Sustainability and technology

SUSTAINABILITY AND TECHNOLOGY

Since the Brundlandt report on sustainability for the United Nations in 1987, sustainability is a multidisciplinary topic:

  • It Includes technological challenges in products and processes, in such a way that developed technology has to guarantee the delivery of goods and services in a manner that does not endanger the possibilities of future generations.


Methodology framework

METHODOLOGY FRAMEWORK

Material

and

Energy Balance

* Resources Extraction, production, distribution of manufactured goods and disposal (“From cradle to grave”).

Material and Energy Balances

Process /product information

Natural Resources Conservation

Natural resourcesconservation

Sustainable Development

Sustainable development

Exergy Balance

EXERGY balance

Air Emissions

Life Cycle Assessment*

Life Cycle Assessment*

GHG Emissions

Efficient use of energy.

Efficient use of energy

Economic analyses of Alternatives

Economic Analyses of Alternatives


General methodology

  • Gather information

  • Production Processes

  • Thermodynamic variables

  • Production costs

Added Value or cost/profit

computation

Life cycle definition

ENERGY balance

EXERGY balance

MATERIAL balance

S Irreversibility

Crude oil

Equivalent

Crude oil

Equivalent

Crude oil

Equivalent

GENERALMETHODOLOGY

GHG EMISSIONS

MULTICRITERIA SELECTION


Methods exergy and energy analyses

MethodsExergy and energyanalyses

  • An Exergy balance, from which the irreversibility rate of a steady flow process can be calculated, is derived by combining the steady flow energy equation (First Law) with the expression for the entropy production rate (Second Law).

  • Exergy is then, defined as the maximum work potential of a material or of a form of energy in relation with its environment.

    Where:

    • H,S = Enthalpy and Entrophy evaluated at non-equilibrium state

    • H0, S0 = Enthalpy and Entrophy evaluated at equilibrium state

    • T0 = reference Temperature

Ex= DH-T0DS = (H-H0) – T0(S-S0)


Exergy is divided mostly in two streams physical exergy and chemical exergy

Exergy is divided mostly in two streams: physical Exergy and chemical Exergy.

Physical Exergy

Chemical Exergy

T

P

X

T0

P0

X

T0

P0

X1

T0

P0

X0

T

P0

X

Mechanical Exergy

Thermal Exergy

Reactional Exergy

Concentration Exergy

For the majority of natural resources, chemical Exergy is the most important contribution to its exergetic value.


Exergy life cycle analysis

EXERGY LIFE CYCLE ANALYSIS

  • On basis of the life cycle approach in combination with Exergy analysis, a method is developed, called the Exergetic Life Cycle Analysis (ELCA).

  • The irreversibility during the complete life cycle allows to evaluate the degree of thermodynamic perfection of the production processes and to conduct the assessment of the whole process chain (Cornelissen, 1999).


D efinition

Definition

  • For the purpose of this presentation, plastic bags are defined as supermarket and retail shopping bags.

  • The functional unit (f.u.) for grocery bags are:

Reusable bags: a repeated use of 300 times

900 plastic bags (with or without additives)

675 paper bags

And in the case of PET bottles:

1 Kg (26 bottles of 1 Lt)


Problem dimension in mexico

Problem Dimension in Mexico

The consumption of H&LDPE’s are 600,000 Ton/year. Then, grocery bags consumption is 107,100 millions/year, considering 900 grocery bags are equivalent to 5.04 Kg, average.

Only 5% of them are recycled

According of “Centro Empresariaal del Plástico”, in 2009 PET bottles consumption, were 375,360 ton (9,700 millions bottles). PET bottles post consumption that are disposed are 7.8 billions/year.


Results

RESULTS

  • Polyehtylene production:

Considering 900,000 Ton/year, the grocery bags consumption is 160,000 millions, it signifies 19,000 barrels/day of crude oil equivalent of the exergy “disposed” in one year,representing an exergy loss of 1’492,937 bpce/year and 149 millions US$/year (with a crude oil price 100 US$/barrel.

Ethylene was obtained from light naphtha by conventional cracking/front-end deethanization, LDPE was produced by a high pressure process, autoclave reactor. We obtained a total of Exergy losses of 244 MJ/f.u. (including emissions), for the Polyethylene production chain.


Energy and material balances of one functional unit through its life cycle

ENERGY AND MATERIAL BALANCES OF ONE functional unit THROUGH ITS LIFE CYCLE.

  • From PE material balance, we have 0.207 crude oil barrels/PE bags (f.u.), equivalent to 17.46 US$/f.u., taking an export price of crude oil of 84.4US$/bl.

  • From the energy balance, we obtained 110.63 MJ/PE bags (f.u.); that quantity and considering a crude oil heat value of 6263.6 MJ/bl, equals to 0.0176 barrels of crude oil per f.u. or 3.5 bl/ton PE.

  • Considering 160 billions bags consumed/year, it is equivalent to dispose into the landfill 4,754,2612 US$/day (!).


Carlos e escobar toledo lol chen alegr a b rbara ram rez

EXERGY BALANCE FOR ALL THE ALTERNATIVES

  • The production of unbleached Kraft paper wastes the highest quantity of Exergy, which represents a much more relevant input than PE bags from the view point of Exergy consumption.

  • The production of polyethylene bags with an oxo degradant additive has the highest Exergy embedded on emissions.

  • It is clear that the production of 1 polypropylene bag that is equivalent to the use of 900 PE bags, involves the lowest losses of Exergy.


Results1

Results


Carlos e escobar toledo lol chen alegr a b rbara ram rez

Partial ranking

Total ranking


Alternatives with the highest priority

Alternatives with the highest priority.

Exergy Diagram for LCA of one grocery bag made from polypropilene


Pet life cycle assessment

PET Life Cycle Assessment

  • Functional Unity

  • “To Contain and transport 26,000 liters of water to drink”

  • The flow of reference corresponding to materials under study is:

1 Ton.

of PET

=

=

2.31 Ton.

of Al

14.84 Ton. of glass

1Kg PET = 26 bottles of 1 liter


Carlos e escobar toledo lol chen alegr a b rbara ram rez

Primary production of PET bottles.

Other products and fuels

Terephthalic

Acid

Mixed Xylenes

REFINERY

p-xylene

CRUDE OIL

Dry Gas (CH4) Propane n-butane iso-butane n-pentane iso-pentane Hexane

PET

Blow process

WETNATURAL GAS

CRYOGENIC

PLANT

  • EthyleneÓxyde

Ethylene

Ethylenglicol

Ethane


Carlos e escobar toledo lol chen alegr a b rbara ram rez

Primary production of glass bottles.

SiO2

RAW MATERIALS

Na2CO3

Glass bottles

Melting

CaCO3

Feldespato

Primary production of aluminum cans.

NaOH

Bauxite

Coke

Hall-Heroult

Process

RAW MATERIALS

Bayer process

Cans

CaO

Na2CO3


Carlos e escobar toledo lol chen alegr a b rbara ram rez

PET PRODUCTION CHAIN

Atmospheric emissions 27569 MJ

CRUDE 674716 MJ

Xylene 34386.11 MJ

p-Xylene 26545 MJ

Terephthalic Acid 18122 MJ

PET 23705 MJ

Methanol 1083.75 MJ

Diethylene Glycol 786 MJ

Ethylene 10843 MJ

Ethylene Oxide 6563MJ

Ethylenglycol 6553 MJ

NATURAL GAS 45115 MJ

Ethane 13799 MJ

Crude Ethylenglycol 334 MJ

EXERGY, ENERGY AND MATERIAL BALANCES OF ONE TON (36,000 bottles) OF PET THROUGH ITS LIFE CYCLE.


Results for virgin and recycled materials mj fu

Results for virgin and recycled materials (MJ/fu)

PET

GLASS

AL

PET

GLASS

AL

PET

AL

GLASS


Data to decision lab

Data to Decision Lab


Multicriteria results

Multicriteria Results

PROMETHEE II Ranking (primary and secondary

Four criteria used:

a) Irreversibility (MJ/u.f.), weight: 30%

b) Energy (MJ/u.f.), weight: 30%

c) Atmospheric Emissions (Kg. de CO2 eq/u.f.), weight: 30%

d) Profit ($/u.f.) 10% weight

Only primary

Only secondary

Primary & secondary


Chemical recycling of pet

CHEMICAL RECYCLING OF PET

PET RECYCLING (MAINLY CHEMICAL) IS A VERY IMPORTANT ALTERNATIVE TO ANALYZE.

(*) To obtain the same product.


Conclusions

CONCLUSIONS

According to the ranking obtained in PROMETHEE Software, the bags made from Propylene and Cotton are the best material based on the criteria considered (Irreversibility, real energy, mass balance, and unit product value).

The exergy analysis shows that the PET recycling process is an important option in the waste disposal since the additional exergy required is only 4.70 MJ/Kg. Also products obtained trough de recycling process are of sufficient quality to be used again in the production of PET.


Conclusions1

CONCLUSIONS

  • Exergy Analysis is a good measure to get a sustainable development. It is then, a very useful tool, which can be successfully used in performance evaluation of waste materials with a very short life cycle.

  • Exergy losses provides not only a measure of both, the energy availability and resource depletion but it is also the most suitable criterion to improve the technological efficiency of the industrial production system. In this way, the Exergy analysis, associated with the energy and mass balances, represents an important advancement in the multi-criteria analysis of products.

  • The analysis of different alternative materials for the manufacturing of retail shopping bags showed how the selected production processes accounted for Exergy destruction and therefore to resource depletion.


Carlos e escobar toledo lol chen alegr a b rbara ram rez

THANKS!


  • Login