Presentación de PowerPoint - SPIRE2030 · Think exergy, not energy • Exergy: ideal potential of...

Alicia Valero

20 September 2017

Exergy as a resource efficiency indicator for process industry

Resource efficiency at all levels

(UNEP, 2011)

• Legislation, pressure on resources and competitiveness force industries to improve their resource use performance.

• The use of energy has been the focus of many optimisations in the past => i.e. reduction of CO2 emissions.

• Today, water and materials are also seen as important resources to be optimised due to potential scarcities (i.e. circular economy action plan).

• Environmental technology/resource efficiency one of the drivers of profound global structural change!?

Heterogeneity of industries and flows

(UNEP, 2011)

• Use of a myriad of different indicators and tools for each sector and even for each industry to assess, optimise and monitor their performance.

• These tools do not allow for a common and cross-sectorial benchmark analysis of the performance of our industry.

Heterogeinity of industries and flows

(UNEP, 2011)

• Where to put the focus on?

All!

Searching for a common scale for resource efficiency

(UNEP, 2011)

Mass (tonnage)

Advantages:

- Physical indicator

- Objective

- Universal

Drawbacks:

- Quality is not taken into account

- The problem of mixing apples with oranges

Searching for a common scale for resource efficiency

(UNEP, 2011)

Market prices (€, $)Advantages:

- Usually associated to value

- No apples with oranges mixing

Drawbacks:

- Volatile

- Arbitrary

- Not universal

Exergy as a common scale for resource efficiency

(UNEP, 2011)

• Engineers make frequent use of efficiencies to assess the performance of

devices and the effectiveness of processes.

• According to the first law of thermodynamics, energy is always conserved.

During conversion, it can change forms, i.e. from chemical energy to heat.

• A good measure of performance takes into account limitations imposed by

the second law of thermodynamics!

Source: Science Europe Exergy Opinion Paper. September 2015

Think exergy, not energy

• Exergy: ideal potential of energy and matter to do work, i.e. ‘available’ or ‘useful’ energy. Anergy is the complementary part of the energy that cannot be converted into work. It is directly related to the entropy change.

• Energy = Exergy + Anergy

• In layman’s terms, the second law of thermodynamics asserts the existence of an energy quality and quantity (measured as exergy) and that all processes result in a quantitative loss of quality in terms of anergy (due to generation of disorder or entropy).

• When this quantity is small, we have an efficient process.


(UNEP, 2011)

• Expansion valve Energy Eff = 3043/3043 100%Exergy Eff = 836/1074 77,8%

The use of an exergy indicator reflects the loss in terms of quality.

Pressure

[bar]

Temperature

[°C]

Enthalpy

[kJ/g]

Entropy

[kJ/kg·K]

Exergy

[kJ/kg]

Inlet, 1 30 320 3043.4 6.6245 1073.89

Exit, 2 5 290 3043.4 7.4223 836.15

Reference, 0 1 25 104.89 0.3674 0


(UNEP, 2011)

• Resource Exergy Indicator: Using a single unit of measure for all

resources

KRI (kWh)=(Exergy fuel+ Exergy raw materials+Exergy water)/tons final

product

Fuels, kWh

Raw materials, kg

Water, m3

Final product, kg

Industrial process

If efficiency improves, KRI improves

Exergy is the resource of value

(UNEP, 2011)

𝑅𝐸𝐼 =𝐵𝑟𝑎𝑤 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙 + 𝐵𝑤𝑎𝑡𝑒𝑟 + 𝐵𝑒𝑛𝑒𝑟𝑔𝑦 𝑎𝑛𝑑 𝑓𝑢𝑒𝑙𝑠

𝑅𝑈

𝑘𝐽 + 𝑘𝐽 + 𝑘𝐽

𝑘𝐽 𝑜𝑟 𝑘𝑔 𝑜𝑟 𝑚3 𝑜𝑟 𝑘𝑊ℎ

• All of the resources can be accounted in the same unit• It is universal: exergy is a physical property• It is absolute: it doesn’t depend on market fluctuation or local availability• It can be aggregated or disaggregated: kJ or kJ + kJ + kJ• It allows assigning costs in a rigorous way based on the exergy (and not on the

price) based on thermoeconomics benchmarking tool

• But…– The reliability will depend on the accuracy of the physical information– Price is price Exergy is most on the academic side because requires some calculus (it

cannot be measured as mass or volume and we don’t pay for exergy) policy makersand industry have to understand why it is interesting.

Why to use the REI?12

Indicators Related to

Energy Use


Material Use


GHG emissions

Indicators Related

Waste Generation


Water Use

Energy x

Specific Energy Consumption x

Exergy Indicator x x x x x

Emergy x

Embodied Energy x

Entropy x

Material Input per Service Unit (MIPS) x

Recycled Content x

Material Flow Analysis (MFA) x

CO2 emissions x

GHG emissions x

Carbon Footprint of a product x

Generation of waste x

Waste treatment and disposal x

Generation of Hazardous Wastes x

Water consumption or water use x

Water abstraction or water withdrawal x

Water footprint of products (WF) x

Water recycled / reused x

Ecological Footprint x x only CO2 x x

Sumario Industrial Results

NPK FERTILIZER INDUSTRY

1. REDUCTION EXERGY COST30%

2. REDUCTION ENERGY INTENSITY 20%

3. INCREASE PRODUCTION 14%15

20

25

30

35

0:00:00 1:12:00 2:24:00 3:36:00 4:48:00 6:00:00 7:12:00

EXERGY COST

PREV_TEST SO-3.1 MO-5,1 FINE COARSE

PREVIOUS TOP-REF %Fertilizer production 436 498 +14,22% kg/hPlant Gas Consumption 135,8 121,27 -10,70% m3/hPlant Electricity Consumption 228,3 222,1 -2,72% kWh

Gas consumption by kg of fertilizer 0,311 0,244 -21,82% (m3/kg)Electricity consumption by kg of fertilizer 0,524 0,446 -14,83% (kW/kg)

Sumario


1. EXERGY COST INDICATOR PROVIDES MORE INTEGRATED INFORMATION THANOTHER INDICATORS

0

0.000001

0.000002

0.000003

0.000004

0.000005

0

0.1

0.2

0.3

0.4

0.5

4:48:00 PM 9:36:00 PM 2:24:00 AM 7:12:00 AM

Ne

tWat

er

KR

I

Pro

du

ct m

ois

ture

Product Moisture 0

0.001

0.002

0.003

0.004

0

1

2

3

4

5

2:24:00 PM7:12:00 PM12:00:00 AM4:48:00 AM9:36:00 AM

Gro

ss w

ate

r U

se

MEt

teri

al

Effi

cien

cy

KRI Material Efficiency - kg Raw / kg Product

0

5

10

15

20

0

10

20

30

40

4:48:00 PM7:12:00 PM9:36:00 PM12:00:00 AM2:24:00 AM4:48:00 AM7:12:00 AM

DEn

Co

-M

J/kg

Exe

rgy

Co

st -

kJ/k

J

KRI - Exergy Cost - kJ Fuel / kJ ProductKRI - Direct Energy Consumption - MJ / kg Product

Industrial Results

Sumario



2. EXERGY COST INDICATOR PROVIDES MORE ACCURATE OPTIMIZED SCENARIOSTHAN OTHER KRI’S

0

5

10

15

20

25

30

35

KRI Exergy Cost - kJ/kJ

Optimizer Test

EXERGYOPTIMIZED

Industrial Results

Sumario




3. A NEW OPTIMUM OPERATION WINDOW HAS BEEN OBTAINED WITH ADECREASE OF 30% OF EXERGY COST

Industrial Results

Sumario




3. A NEW OPTIMUM OPERATION WINDOW HAS BEEN OBTAINED WITH ADECREASE OF 30% OF EXERGY COST

4. PLANT OPERATORS EMBRACE THE PROPOSED ALTERNATIVE OPERATIONWINDOWS INSTEAD OF FORMER SCENARIOS

Industrial Results

Sumario

DOW CHEMICAL IBERICA

1. LOCATION OF HOSTPOST AND INEFFICIENCIES

2. ESTIMATED IMPROVEMENTES IN UTILITY PLANT 3 M€/yr

Industrial Results

Sumario




OTHER RESULTS

1. MORE COMPLEX SYSTEM, INSTABILITIES IN MONITORING KRI’S

Industrial Results

Sumario




OTHER RESULTS


2. DIFFICULT EVALUATE INDEPENDENCE OF INTERFERENCES OF PROPOSEDOPERATION AND CONTROL SYSTEM

Industrial Results

Sumario




OTHER RESULTS


2. DIFFICULT EVALUATE INDEPENDENCE OF INTERFERENCES OF PROPOSEDOPERATION AND CONTROL SYSTEM

3. CPP’S ARE CONFIRMED AS CRITICAL AND MOST OF THE TRENDS PREDICTEDARE CORROBORATED

Industrial Results

Thanks for your attention

Alicia Valero ([email protected])


• All materials or power flows have a defined and computable amount of exergy with respect to a reference environment.

2 2

0 0 0 0 0 0 0 0 0

1( ) ( ) ( )

2

n

i i i

i

b u u p v v T s s C C g z z N N

• An opportunity to measure the quality of natural resources and the inefficiencies in real processes.

Exergy of Energy sources

• For Kinetic, potential, electrical and magnetic energy Energy = Exergy • Exergy of a fossil fuel can be approximated to HHV• Exergy of thermal flows will depend on the temperature of the flow and the

reference

01Q

TB Q

T

Fuel HHV bch

Anthracite 30675 31624

Bituminous 28241 29047

Subituminous 23590 24276

Lignite 16400 17351

Fuel-Oil 1 46365 46259

Fuel-Oil 2 45509 45517

Fuel-Oil 4 43920 44002

Natural gas 42110 39393

Exergy of Water sources

Water flows will have two important terms:

Thermo-mechanical: based on its state of aggregation (s, l, g) and the pressureand temperature. It will be relevant in most of the industrial processesChemical: that will be linked to other water uses as solutions with salts, metals,minerals and organic matter.

Exergy of Raw Materials

Raw materials are assessed through their chemical exergy and exergy replacementcosts (if these are obtained from mineral deposits).

Quantity of exergy needed, using the best available technology, to replace a

material from its surrounding environment and original composition and

concentration before extraction.

( )chib G n bf e chne i

e

Exergy of Raw Materials

It provides a “fairer” value to non-energy resources. It allows to allocate costs among non-energy flows in a rational way.

Chemical exergy

CaCO3

Fe2O3

Mass

CaCO3

Fe2O3

Exergy Replacement

Cost

CaCO3

Fe2O3

Price

CaCO3

Fe2O3


(UNEP, 2011)

First set of Key Resource Indicators

Headline

indicators

• Material efficiency (kg/OU)

• Direct primary energy consumption (J/OU)

• Water use (m3/OU)

• Resource Exergy indicator (J/OU)

• Headline indicators focused on different categories of

resources:

• Materials

• Energy

• Water

• Exergy (quantity and quality of resources)The exergy indicator, based on rigorous thermodynamics, is more powerful than the others (measures quantity and quality). However, general acceptance is still low and therefore, the other indicators were included.


(UNEP, 2011)

• Fertilizar case study

Proofed to be the most accurate and reliable indicator to optimize

resources.

A 30% decrease of the exergy cost was achieved (equivalent to

200,000 €/year).


(UNEP, 2011)

• Applicable to all SPIRE sectors

Proofed applications to Fertilizer and Chemical industry

Initial assessments to ceramic, cement and steel

industry also show promising results.

Industrial sectors under the IPPC Directive and the IED SPIRE

Unit Material Cost

Direct Primary Energy Consumption

Gross / Net Water Use

Resource Exergy Indicator

Ceramic Manufacturing Industry Y

Common Waste Water and Waste Gas Treatment/ Manag. Systems in the Chemical Sector Y

Emissions from Storage N

Energy Efficiency Y

Ferrous Metals Processing Industry Y

Food, Drink and Milk Industries N

Industrial Cooling Systems Y

Intensive Rearing of Poultry and Pigs N

Iron and Steel Production Y

Large Combustion Plants N

Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilizers Y

Large Volume Inorganic Chemicals – Solids and Others Industry Y

Large Volume Organic Chemical Industry Y

Manufacture of Glass N

Manufacture of Organic Fine Chemicals Y

Non-ferrous Metals Industries Y

Production of Cement, Lime and Magnesium Oxide Y

Production of Chlor-alkali Y

Production of Polymers Y

Production of Pulp, Paper and Board N

Production of Speciality Inorganic Chemicals Y

Refining of Mineral Oil and Gas Y

Slaughterhouses and Animals By-products Industries N

Smitheries and Foundries Industry Y

Surface Treatment Of Metals and Plastics Y

Surface Treatment Using Organic Solvents Y

Tanning of Hides and Skins N

Textile Industry N

Waste Incineration N

Waste Treatment Y

Wood-based Panels Production N


(UNEP, 2011)

• The analysis of Exergy Losses allows to identify, locate and quantify

inefficiencies in real processes. It helps to locate causes of

consumed resources.

• If exergy is destroyed in real processes, some natural resources are

consumed and lost forever, which creates cost. Cost is in fact a

sacrifice of resources.

• As well as minimizing degradations is equivalent to improve

resources efficiency.

• With exergy as the objective function to be improved, we can at the

same time optimize all flows.

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