This document discusses exergy analysis as a tool for evaluating and improving the sustainability of industrial processes. Exergy analysis examines both the energy and entropy of process streams to identify opportunities to reduce resource use and waste generation. The document provides examples of student projects applying exergy analysis to waste gasification and cement production processes. It finds that exergy analysis can help optimize processes by pinpointing sources of inefficiency and evaluating design tradeoffs between environmental and economic performance.
Simulation of the effects of turbine exhaust recirculationZin Eddine Dadach
For an effective carbon capture by an amine mixture, the molar percentage of CO2 in the flue gas should be at least equal to 10%. Moreover, in order to reduce technical problems due to amine oxidative degradation, the molar percentage of O2 in the flue gas should be limited to 5%. One possible option for increasing the concentration of CO2 and decreasing the amount of O2 in the flue gas from power plants using natural gas is recirculation of a part of the flue gas.
Energy is not only about quantity. Its quality is equally important. This minute lecture, inspired by an idea from Camatini & Kester, introduces the concept of exergy, the quality measure for an amount of energy. It uses the example of space heating with various methods: electric heating, fossil-fired boiler and heat pumps.
Energy and exergy analysis of a 250 mw coal fired thermal power plant at diff...eSAT Journals
Abstract In this present investigation exergy and energy efficiencies of a coal fired 250 MW thermal power plant operating in eastern part of India are determined both for 100% and 90% load based on actual operating data. The efficiencies are evaluated for the overall plant as well as for different equipments like boiler, turbine, all feed water heaters and condenser. Similarly effectiveness of the feed water heaters is evaluated for both the loads. Exergy destruction % for each of the equipment are also given for clear understandingof the loss of available energy due to irreversibilities involved in the processes for each equipment and the whole plant. It is observed that a major irreversibility or, exergy destruction takes place at boiler though 1st law energy efficiency is quite high. This signifies that there might have further scope of improvement in this equipment. Similar analyses are carried out for other equipments. The results obtained in present analysis are compared with those of other investigators. Keywords: Energy, Exergy, Efficiency, Effectiveness, Exergy destruction, Power plant
A review of 1st and 2nd Law of Thermodynamics is presented, as well as the introduction to the concepts of availability and exergy. Examples of calculations for power plants are presented using both analytical methods and CyclePad(TM) simulator.
Simulation of the effects of turbine exhaust recirculationZin Eddine Dadach
For an effective carbon capture by an amine mixture, the molar percentage of CO2 in the flue gas should be at least equal to 10%. Moreover, in order to reduce technical problems due to amine oxidative degradation, the molar percentage of O2 in the flue gas should be limited to 5%. One possible option for increasing the concentration of CO2 and decreasing the amount of O2 in the flue gas from power plants using natural gas is recirculation of a part of the flue gas.
Energy is not only about quantity. Its quality is equally important. This minute lecture, inspired by an idea from Camatini & Kester, introduces the concept of exergy, the quality measure for an amount of energy. It uses the example of space heating with various methods: electric heating, fossil-fired boiler and heat pumps.
Energy and exergy analysis of a 250 mw coal fired thermal power plant at diff...eSAT Journals
Abstract In this present investigation exergy and energy efficiencies of a coal fired 250 MW thermal power plant operating in eastern part of India are determined both for 100% and 90% load based on actual operating data. The efficiencies are evaluated for the overall plant as well as for different equipments like boiler, turbine, all feed water heaters and condenser. Similarly effectiveness of the feed water heaters is evaluated for both the loads. Exergy destruction % for each of the equipment are also given for clear understandingof the loss of available energy due to irreversibilities involved in the processes for each equipment and the whole plant. It is observed that a major irreversibility or, exergy destruction takes place at boiler though 1st law energy efficiency is quite high. This signifies that there might have further scope of improvement in this equipment. Similar analyses are carried out for other equipments. The results obtained in present analysis are compared with those of other investigators. Keywords: Energy, Exergy, Efficiency, Effectiveness, Exergy destruction, Power plant
A review of 1st and 2nd Law of Thermodynamics is presented, as well as the introduction to the concepts of availability and exergy. Examples of calculations for power plants are presented using both analytical methods and CyclePad(TM) simulator.
Basic Mechanical Engineering Unit 4 Thermodynamics@by V.P.SinghVarun Pratap Singh
Download Link (Copy URL):
https://sites.google.com/view/varunpratapsingh/teaching-engagements
Basic Mechanical Engineering Unit 4 Thermodynamics for B.Tech. First-year students
Unit IV:
Thermodynamics: Thermodynamic system, properties, state, process, Zeroth, First and second law of thermodynamics, thermodynamic processes at constant pressure, volume, enthalpy & entropy.
Steam Engineering: Classification and working of boilers, mountings, and accessories of boilers, steam properties, use of steam tables, P-V, T-S diagram
Exergy analysis as a tool for energy efficiency improvements in the Tanzanian...Patrick VanSchijndel
The story behind energy efficiency in industrial processes is productivity, industrial competitiveness, jobs, and a clean environment. A method for energy efficiency evaluation is to carry out an energy analysis, a so called First-Law analysis. With such an energy-audit, however, it is impossible to compare different kinds of energies like electrical energy, mechanical work, high and low temperature streams, etc. A better tool for comparing different kinds or qualities of energy is exergy analysis in which the quality or exergy of all energy streams is calculated. In this way the energies are calculated and compared in a more scientifically correct and accurate manner. Advantages of the exergy analysis is to get a better understanding of the energy losses in, parts of, an industrial process, which means it is easier to find out in what part of a process energy use can be decreased.
In this paper two analyses of energy intensive processes in Tanzania and Zambia are described. First, the energy and exergy analyses of the Tanzania Portland Cement Co., Ltd., at Wazo Hill in Dar es Salaam are presented. It was possible to perform an exergy analysis using available energy and mass balance data and some basic thermodynamic data like enthalpies and Gibbs Free energies. The analysis predicted that the energy use in the cement production could be decreased by 15% and higher by improving the kiln process and by installing new equipment (pre- calciners). Secondly, energy evaluations concerning sugar production were performed. For heat-exchangers, exergy analysis identified temperature difference between the hot and the cold streams as a critical parameter in equipment efficiency calculations. A big problem affecting this temperature difference in heat exchangers is fouling, the formation of solid deposits on heat exchanger surfaces. Elimination or minimising fouling can lead to low exergy losses in heat exchangers and hence high equipment effectiveness. A research project formulated to investigate the problem of fouling in the sugar industry in Zambia is described.
Generally it can be concluded that an exergy analysis is more accurate than a thermal analysis because not only quantity but also quality of the energy used is calculated.
What is Thermodynamics?
Applications of Thermodynamics
Macroscopic and Microscopic Viewpoint of Thermodynamics
Thermodynamic System
Closed System
Open System
Isolated System
Control Volume
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
thermodynamics. in physical world outside and inside the living body. important factor for heat and energy for the living.
different forms of energy, kinetic energy and pottential energy.
different forms of system, open and closed. laws of thermodynamics and gibbs free energy. entrophy and enthalphy
This is an overview of thermodynamics. this principles and topics are essential for electrical engineering students who are going to study about energy conversion. this material is prepared for Debre Birehan university Power stream students. this material is basic not detailed.
Basic Mechanical Engineering Unit 4 Thermodynamics@by V.P.SinghVarun Pratap Singh
Download Link (Copy URL):
https://sites.google.com/view/varunpratapsingh/teaching-engagements
Basic Mechanical Engineering Unit 4 Thermodynamics for B.Tech. First-year students
Unit IV:
Thermodynamics: Thermodynamic system, properties, state, process, Zeroth, First and second law of thermodynamics, thermodynamic processes at constant pressure, volume, enthalpy & entropy.
Steam Engineering: Classification and working of boilers, mountings, and accessories of boilers, steam properties, use of steam tables, P-V, T-S diagram
Exergy analysis as a tool for energy efficiency improvements in the Tanzanian...Patrick VanSchijndel
The story behind energy efficiency in industrial processes is productivity, industrial competitiveness, jobs, and a clean environment. A method for energy efficiency evaluation is to carry out an energy analysis, a so called First-Law analysis. With such an energy-audit, however, it is impossible to compare different kinds of energies like electrical energy, mechanical work, high and low temperature streams, etc. A better tool for comparing different kinds or qualities of energy is exergy analysis in which the quality or exergy of all energy streams is calculated. In this way the energies are calculated and compared in a more scientifically correct and accurate manner. Advantages of the exergy analysis is to get a better understanding of the energy losses in, parts of, an industrial process, which means it is easier to find out in what part of a process energy use can be decreased.
In this paper two analyses of energy intensive processes in Tanzania and Zambia are described. First, the energy and exergy analyses of the Tanzania Portland Cement Co., Ltd., at Wazo Hill in Dar es Salaam are presented. It was possible to perform an exergy analysis using available energy and mass balance data and some basic thermodynamic data like enthalpies and Gibbs Free energies. The analysis predicted that the energy use in the cement production could be decreased by 15% and higher by improving the kiln process and by installing new equipment (pre- calciners). Secondly, energy evaluations concerning sugar production were performed. For heat-exchangers, exergy analysis identified temperature difference between the hot and the cold streams as a critical parameter in equipment efficiency calculations. A big problem affecting this temperature difference in heat exchangers is fouling, the formation of solid deposits on heat exchanger surfaces. Elimination or minimising fouling can lead to low exergy losses in heat exchangers and hence high equipment effectiveness. A research project formulated to investigate the problem of fouling in the sugar industry in Zambia is described.
Generally it can be concluded that an exergy analysis is more accurate than a thermal analysis because not only quantity but also quality of the energy used is calculated.
What is Thermodynamics?
Applications of Thermodynamics
Macroscopic and Microscopic Viewpoint of Thermodynamics
Thermodynamic System
Closed System
Open System
Isolated System
Control Volume
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
thermodynamics. in physical world outside and inside the living body. important factor for heat and energy for the living.
different forms of energy, kinetic energy and pottential energy.
different forms of system, open and closed. laws of thermodynamics and gibbs free energy. entrophy and enthalphy
This is an overview of thermodynamics. this principles and topics are essential for electrical engineering students who are going to study about energy conversion. this material is prepared for Debre Birehan university Power stream students. this material is basic not detailed.
This presentation is from Affiliate Summit East 2015 (August 2-4, 2015 in New York, NY). Session description: This session will provide a blueprint for activating a community of brand evangelists by leveraging best practices to reach members of large-scale affinity groups to driving customer acquisition.
Principal Tools for a Cleaner Chemical Technology, presented at the european ...Patrick VanSchijndel
Principal Tools for a Cleaner Chemical Technology, Process improvements have been tremendous in the last century but production volume increase will overshadow these good results in terms of resource use and environmental impact. It will be important to use the right tools in order to achieve the necessary sustainable development within the industry. These tools should be combinations of exergy analysis, LCA and economic analysis. The focus should be on the development of these combinations and on the teaching of these combinations in engineering curricula.
Exergy Based Performance Analysis of FGPS (NTPC Faridabad)Santosh Verma
Compute energy and exergy flows using the thermodynamic property values with the real time operation parameters at terminal points of crucial systems and evaluate exergy destruction at different systems
THERMAL RECYCLING OF HETEROGENEOUS CHLORINE CONTAINING PLASTIC WASTE STREAMSPatrick VanSchijndel
This study describes a back to feedstock method for heterogeneous chlorine rich containing plastic waste streams, which has been developed at the Technical University of Eindhoven (TUE). In this process plastic waste containing 20 wt% of chlorine is gasified with the aid of steam at 1250 K into a gas consisting of H2, CO, CO2, CH4 and HCl. The conversion of the organic part of the waste is complete, without the formation of tars. The inorganic materials are blown out of the reactor and can be separated as solid material. The formed HCl is recovered as a 30 wt% muriatic acid or pure HCl gas and can be reused as feedstock for the VC production. The gasses can function either as a syngas or as a fuel gas for energy recovery with high efficiency. Cogeneration of electricity and heat with high efficiencies (40-50%) via a combined cycle system with relatively small scale processes (5-30 kton per year) makes this process interesting for conversion of complex plastic waste streams. Exergy analyses show that this process is much more efficient that the usual waste incineration route.
Plant-Wide Control: Eco-Efficiency and Control Loop ConfigurationISA Interchange
Since the eco-efficiency of all industrial processes/plants has become increasingly important, engineers need to find a way to integrate the control loop configuration and the measurements of eco-efficiency. A new measure of eco-efficiency, the exergy eco-efficiency factor, for control loop configuration, is proposed in this paper. The exergy eco-efficiency factor is based on the thermodynamic concept of exergy which can be used to analyse a process in terms of its efficiency associated with the control configuration. The combination of control pairing configuration techniques (such as the relative gain array, RGA and Niederlinski index, NI) and the proposed exergy eco-efficiency factor will guide the process designer to reach the optimal control design with low operational cost (i.e., energy consumption). The exergy eco-efficiency factor is implemented in the process simulation case study and the reliability of the proposed method is demonstrated by dynamic simulation results.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Solar air heater (SAH), which is the most essential component of solar drying systems, receive solar energy and convert it into thermal energy. This review presents descriptions and previous works conducted on performances analysis of SAHs. Exergoenviroeconomic, exergoenvironmental, environmental, and exergy analyses are also presented. In addition, results on the performances of SAHs are summarized. The exergy and energy efficiencies of SAHs at laboratorium testing range from 8% to 61% and from 30% to 79%, respectively.
Elements of Sustainable Construction and Design ParametersAjit Sabnis
This presentation covers facets of Embodied Energy, Embodied Carbon, LCA methods, Benchmarking and establishing baselines, Parameters for sustainable design.
Exergy analysis of inlet water temperature of condenserIJERA Editor
The most of the power plant designed by energetic performance criteria based on first law of thermodynamics. According to First law of thermodynamics energy analysis cannot be justified the losses of energy.The method of exergy analysis is well suited to describe true magnitude of waste and loss to be determined. Such information can be used in the design of new energy efficient system and increasing the efficiency of existing systems.In the present study exergy analysis of the shell and tube condenser is carried out. As the condenser is one of the major components of the power plant, so it is necessary to operate the condenser efficiently under the various operating condition to increase the overall efficiency of the power plant. In the present study inlet temperature of the condenser is optimized using the exergy method. The main aim of paper is to be find out causes of energy destruction that can be helpful to redesign the system and to increase the efficiency
Preliminary Study for Exergetic Analysis on Sugar Production in Tanzania the ...Patrick VanSchijndel
Tanzania is striving to reach the levels of economic well being which the developed countries have achieved. However, the industrial development as was undertaken by the first world countries would be catastrophic for the environment. Therefore this study focussed on how to combine economic growth with sustainable development.
Due to the bad condition in which some of the equipment at TPC was, it proved not to be possible to map all the energetic difficulties at the factory. Though, it was possible to address the main bottlenecks of the process and suggestions for improvement were done. However, improving the course of the process is not sufficient to improve the sustainability of the factory. Non-technical aspects, like behaviour of operators and management can also do one's bit for a more reliable, time and cost efficient and less polluting factory. Of course this will inevitably ask for investments.
Despite the fact that some well-intentioned criticism is uttered in this report, TPC seems to have the power to survive, as it did for the past 65 years. If TPC’s new owner deals with the factory’s bottlenecks and takes the issues dealt with in this report to hart, the future of TPC looks promising.
Humankind faces the most serious challenge ever – sustainable development. This is described from an
educational perspective. A new educational paradigm based on increasing the respect of nature instead of
exploiting it is presented, as well as fundamental scientific principles, concepts and methods in order to improve
the education towards sustainable development. Implications on present education at high school or secondary school level are discussed. Gives a great introductionary overview of thermodynamic analysis of society, using the Exergy Approach
In the early 2000's the energy directory in the Netherlands (Novem and later SenterNovem) published a handy booklet with many energy related tables and facts.
Boekje energievoorziening van_nederland_-_a4_versie Dutch version of booklet ...Patrick VanSchijndel
This is a booklet that describes the energy situation in The Netherlands. Being a small but highly developed country with a large number of people means that large scale renewable energy systems have to be smart.
Phidgets are devices that interface computers and technology to the real world. They come with 100+ different sensors, servo and motor and LED control and much more
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
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Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
Exergy analysis - a tool for sustainable technology - in engineering education
1. Exergy analysis - a tool for sustainable technology - in engineering education
P.P.A.J. van Schijndel, J.M.N. van Kasteren and F.J.J.G. Janssen
Eindhoven University of Technology (TUE), The Netherlands
Faculty of Chemistry and Chemical Engineering
Centre for Environmental Technology (CMT)
Abstract
The world is changing rapidly due to the increasing wealth and size of the population. There is a
growing need for more efficient and therefore sustainable production processes. Therefore, the
educational programme for engineers should contain the tools for the optimisation of processes into
more sustainable ones. Such tools are for instance process integration and exergy analysis.
For chemical and physical processes, exergy analysis is a powerful concept. Exergy is a measure for
quality of mass and energy streams. By use of an exergy analysis, processes can be optimised into
more sustainable processes. Both environmental performance and economical aspects can be
combined to improve its performance by the method of exergoeconomics, a new principle for
combined economical and environmental performance optimisation. In this paper, exergy analyses
are presented, which have been carried out by chemical engineering students, focused on waste and
biomass gasification processes.
These experiences show how the environmental performance of existing processes can be improved
within economical constraints. Moreover, the students learn a method of analysing processes, which
is not yet incorporated in the engineering curriculum, although exergy is a well-known concept. The
first experiences have been encouraging so that a new course called ‘Exergy-route for a Sustainable
Process Technology’, specifically on exergy, will start in the new academic year. The contents of this
course are included in this paper.
Introduction
As our world is aiming at a more sustainable society, there are some major problems to overcome.
The environmental burden of the society is related to population size, economical position and
influence of GNP on environment (Welford, 1993). Since world population is expected to double
from 5 billion to 10 billion and GNP is going to raise by factor four within 30 years the
environmental impact of industry and their products has to fall by about 90% to maintain the same
level of environmental impact. This will be one of the greatest challenges of this time. So the
environmental burden related to production, use and discarding of materials and products has to be
lowered. How is this to be achieved?
First, production processes have to be reviewed followed by improving them into processes that are
more efficient. There are many tools for improving a process, e.g. environmental Life Cycle
assessment, LCA, and exergy analysis. This study is focussed on exergy analysis.
Sustainable processes
Cleaner production of materials, goods and services is one of the tools for sustainable development.
It means production in a way in which resources and energy are used in an efficient way and only
small amounts of waste and emissions are produced. Other important factors are the use of
renewable resources and the increase in quality of the products. This does not mean that the cleaner
production concept is contradictory to the economic approach of minimising costs and maximising
2. profits. It is the challenge to create win-win situations such as minimising the use of resources and
cutting back on emissions, which can also decrease the costs of a given process.
An industrial process can be simply outlined, as a black box, see Figure 1. Resources and energy
(work) are the inputs and products, wastes, emissions (air, soil, water), excess heat etc. are the
outputs of this process.
Figure 1. Schematical drawing of an industrial process
With the help of design tools like exergy analysis, LCA and others it is a goal for engineers to
optimise the process in a way it consumes fewer resources like raw materials and energy and
produces less emissions and waste.
Ordinary routes for achieving this used to be end-of-pipe treatment in the way of costly waste water
treatment plants, filters and scrubbers. These are both not real solutions, as they actually do not
decrease the environmental load, they only shift it from one phase, i.e. water or air to soil and water.
In many cases, however, expensive end-of-pipe treatment solutions are unavoidable.
The tools, as mentioned before, are aiming at changing or optimising the given process so it turns
out more efficient and sustainable. In the next chapter, the exergy method of improving processes
will be described.
Exergy analysis as a tool for sustainable processes
Exergy analysis resembles the enthalpy or energy analysis. The difference is that in exergy analysis
enthalpy and entropy are applied. An exergy balance can be performed for a whole plant or for
different unit operations. Information about exergy analysis can be found in literature (Szargut et al.,
1988 and Kotas, 1995).
The following definition for exergy is used normally:
‘Exergy is the maximum amount of work that can be obtained from a stream of matter, heat or work
as it comes to equilibrium with a reference environment. It is a measure of the potential of a stream
to cause change, as a consequence of not being completely stable relative to the reference
environment. Exergy is not subject to a conservation law, but it is destroyed due to irreversibility’s
during any process.’
A basic example is the possibility of converting mechanical work into heat with 100% efficiency.
Heat has a lower exergy, or quality of energy, compared with work. Therefore, heat cannot be
Process
Useful Energy
Resources
Product(s)
Wastes
Materials
and
Waste Energy
Emissions
3. converted into work by 100% efficiency. Some examples of the difference between energy and
exergy are shown in Table 1. From this table hot water and steam with the same enthalpy have
different exergy or quality values. Steam has a higher quality than hot water. Fuels like natural gas
and gasoline have exergetic values comparable to their net combustion value. Work or electricity has
the same exergy as enthalpy. Exergy can be calculated by product of energy and quality (Szargut et
al., 1988 and Kotas, 1995).
Table 1. Examples of energy and exergy of different matter
Material Energy
[J]
Exergy
[J]
Quality
[-]
Water 80°C 100 16 0.16
Steam 1 bar and 120°C 100 24 0.24
Natural Gas 100 99 0.99
Electricity / work 100 100 1.00
Exergy values according to heat transfer (Carnot); Reference State is 298 K.
The calculations for the basis of table 1 are quite simple. For the calculations of exergy there are
several components, which can be calculated separately like physical exergy (temperature and
pressure), chemical exergy and mixing exergy. The exergy amount of a heat transfer stream
according to the temperature difference of this stream and the environment is given by the Carnot
factor times the energy content:
Quality =
−
ST
T0
1 (Carnot Quality factor)
Exergy = Energy (Transferred) ∗ Quality
Where T0 is the reference temperature (298 K) and Ts is the temperature of the stream.
The Reference State is very important in exergy analysis because every compound or heat other than
a reference substance or temperature is able to perform work.
The exergy analysis is more accurate and scientifically correct when compared to an ordinary energy
analysis because:
• Exergy analysis provides a better view on the real efficiency of a process;
• Exergy analysis is very useful to find the unit operation were efficiency improvements are the
most suitable or useful.
Each process designer or process engineer should perform an exergy analysis to make all exergy
losses visible in the process under study. The method is very powerful when comparing two or more
solutions in an objective and quantitative manner. Of course the exergy analysis does not give direct
answers on how to improve the process but it gives the best clues where to start, namely at the point
where the largest exergy losses appear.
Exergy analysis is especially useful in the design phase and during optimisation of new processes. It
is also a very useful tool when used for comparison of different production routes.
In using exergy analysis, it becomes clear that, for instance, a heat exchanger can be optimised by
increasing its heat-exchanging surface, because this decreases the temperature difference, ∆T, at the
same heat load conditions. At the same time costs will go up with increasing heat exchanging
surface. Therefore, there will be an economical/exergetical optimum as visualised in Figure 2.
4. Figure 2. Heat exchanger optimisation
Examples of processes reviewed with exergy analysis
In 1997 and 1998 several students have performed exergy analyses as a part of their study on
process improvements. These studies involved cement and glass manufacturing and the processing of
wastewater sludge and PVC waste. Two cases, cement production and PVC waste gasification, are
presented in this paper.
Case 1: Cement production in Tanzania
The production of cement is one of the most energy intensive production processes known. This
process also emits a lot of CO2, due to the decomposition of CaCO3. Cement production accounts
for about 8% of total CO2 emissions from all human activities (Unanimous, 1993). It is beneficial
from both an environmental as energetic point of view to optimise or redesign this process to
improve it’s efficiency. Therefore, a project was focussed on the possibility to perform an exergy
analysis on a real cement production plant. When focussing on the overall efficiency of a process it is
better to perform an exergy analysis than to calculate only the energy use per ton of cement. This is
caused by the fact that the different resources have different exergetic values.
The plant chosen was the Tanzanian Portland Cement Company, TPCC, at Wazo Hill in Dar Es
Salaam. Although there was not so much in depth process data available, several exergy analyses
could be carried out successfully (Den Boer, 1998, Van Schijndel et al., 1998 and Hoenders, 1998).
Table 2. Exergetic efficiency at Wazo Hill
Process unit Exergetic efficiency
(Fratzcher)
Theoretical Efficiency*
Pre-heater 73 % 90 %
Kiln 44 % 80 – 85 %
Cooler 58 % 90 %
Overall 38 % 70 – 80 %
*) Estimated values, zero heat loss
exergy consumption
(operational costs)
Heat exchanger surface
(capital costs)
minimum ∆T
Larger ∆T
Optimum ∆T
5. The analysis focussed on the pyroprocessing section, see Figure 3, where the raw grinded materials
are pre-heated, burned at 1450°C and cooled down to form clinker, the main product of Portland
cement.
Results of the exergy studies in Table 2, showed that the overall efficiency of the pyroprocessing
section is about 38% (the so-called Fratzcher efficiency; see Sorin et al. 1998). This is low compared
to modern state of the art processes but average when compared to other old cement plants.
Kiln
Cooler
Pre-
Heater
Fuel
Exhaust
Gas
Raw meal
Hot meal
Air
Hot
Clinker
Clinker
Primary
To Electrostatic
Filters
Figure 3. Cement production, process layout
According to this results the highest losses occur in the kiln (fuel burning, bad insulation) and cooler
(bad heat transfer). Since all the equipment is coupled, optimisation has to be done by considering
the whole process.
There are many opportunities to improve the process:
• Only produce at an optimal throughput; decrease amounts of stops
• Installation of high efficiency clinker cooler
• Install new burner and automate clinker burning process
• Better insulation in pre heater, kiln and clinker cooler
• Improvement of pre heater
• Improving dust system
• Better training of process operators
When the plant is retrofitted to modern standards, using a precalciner, the efficiency will rise to 43%
and higher. This optimisation is an economical and an environmental one since production capacity
doubles, the costs drop sharply and the fuel use decreases by over 20%. For TPCC, the pay back
time for the retrofitting has been estimated at 1.5 years. Several other exergetic optimisations, like
pre-heater and cooler retrofitting, proved to be economically and environmentally feasible too.
Case 2: PVC waste gasification versus waste burning
At the TUE, a research project is running to develop a more environmental friendly route for the
waste processing of PVC. In stead of burning or recycling the process of gasification has been
chosen, see Figure 5. Since the experimental work has been successful (Slapak et al., 1996) a student
was asked to perform an exergy study on both the new gasification process as the burning process of
6. PVC. In the gasification process, PVC waste is gasified in a fluidised bed reactor containing a
catalyst, at 850° C together with steam. The gasses formed, HCl, CO, CO2 and H2 are quenched and
HCl is stripped of. The gasses are then burned in a gasturbine, excess heat is used in the process in a
steam turbine.
Figure 4. Schematical drawing of the PVC waste gasification process
Outcome of this analysis has been that the exergetic efficiency of PVC waste gasification is 60%
higher than PVC burning (Table 3.). Main reason for the high efficiency of the gasification process
are the use of a high temperature gas-turbine and the controlled gasification and burning process
compared to the chaotic PVC burning process. Some small optimisation calculations showed that the
gasification process has potential for further optimisation. These studies are currently under
investigation by post-graduate design course students.
Table 3. Burning versus gasification efficiencies.
Process Exergetic Efficiency (%)
(10% heat loss)
Exergetic Efficiency (%)
(zero heat loss)
PVC - Burning 29 32
PVC gasification 49 50
Both processes produce electricity and a 30% HCl-stream
Although the students were satisfied with the studies and the outcome of the research they felt that
the time needed to understand and use the exergy analysis method took too long. One cause was the
absence of a graduate course in exergy analysis. Such course has been developed and started in
September 1998 for the first time.
PVC
Steam
WorkAir
Muratic acid
Work Work
Water
Gasifier
Stack gasses
Work
HCl-stripping Compressor Burner
Gas turbine
Steam cycle
7. New course in exergy analysis at TUE
Some years ago the TUE started a post graduate course for process and product design for chemical
process and product engineers. In this course extended thermodynamics including exergy was
introduced. Since, as explained, second law thermodynamics are increasingly important in designing
a process, combined by the growth of powerful simulation programmes which perform the extensive
calculations, there was the need to translate the course into a MSc. Course called ‘exergy route
towards sustainable development’.
Table 4. Overview of course ‘Exergy Route towards sustainable Process Technology’
1. Introduction: process efficiency and sustainable development.
Economical welfare, sustainable development, efficiency of chemical processes, depletion of non renewable
resources, environmental problems, ‘nature-oriented’ technology, thermodynamic analysis of industrial processes,
social relevance of the second law of thermodynamics.
2. Thermodynamic background of exergy analysis.
Entropy, the first and second law for an open system,, entropy balance and entropy production for irreversible
processes, dissipation of energy and materials, maximum of work potential (inclusive chemical reactions).
3. Fundamental aspects of energy.
Energy sources, fossil fuels, nuclear energy, sustainable energy sources (solar energy, biomass), availability of
energy, conversion technology of energy sources.
4. Exergy balance and irreversibility.
Thermal exergy, exergy by work, exergy of material flows, physical and chemical exergy, conceptual
surroundings, exergy balance, irreversibility and the Gouy-Stodola relation, rational efficiency.
5. Exergy analysis of physical and chemical methods.
Exergy analysis of processes: compression expansion, heat transfer, mixing and separation processes, distillation,
chemical reactors, combustion processes.
6. Exergy analysis of energy systems.
Exergy analysis of energy production and transfer, steam cycles, gas turbines, heat-power coupling, heat pumps,
cooling installations.
7. Exergy analysis of chemical plants.
Example: H2SO4 plant, Linde liquefaction of gasses.
8. Process integration.
Improvement of the efficiency of separation processes, chemical reactors and plants by means of exergy analysis.
9. Thermodynamic design.
Thermodynamic and economical utilisation of exergy, optimisation criteria for transport and separation processes,
design of optimal system structure and equipment, common sense second law approaches for optimal design.
10. Environmental and ecological aspects of exergy.
Depletion of non-renewable resources, cumulative exergy use, exergetic costs, ecological efficiency, life cycle
assessment, recycling and ecological economy.
11. Guest lecture.
Utilisation of exergy analysis in the process industry, recent examples from the industrial practice.
8. In the course there will be emphasis on the understanding the concept of exergy, the causes for
exergy loss in any process and the possibilities to decrease exergy this loss by process optimisation.
The following conceptions are lectured in the course: Process efficiency and sustainable
development, fundamental aspects of energy, exergy balance and irreversibility, exergy analysis of
physical and chemical processes and energy systems, analysis of whole plants and process
integration, environmental en ecological aspects of exergy. In Table 4 more elaborate contents of the
course can be found.
Besides this special and non compulsory course for third-fourth years chemical and mechanical
engineering students, exergy analysis is also incorporated in other (environmental) courses at the
Eindhoven university of Technology. There will be a case study using exergy in the second year
course 'Sustainable development' and there are more examples of exergy calculation in the third years
course 'Environmental Technology'.
Conclusions
The case studies have shown that there are many possibilities to increase the energy efficiency of
processes by using the method of exergy analysis.
It is clear that the use of exergy analysis cannot be missed in the engineering curricula of chemical
and process engineers. Exergy analysis can add extra insight to the knowledge of the engineer. This
knowledge is very essential (crucial) to design and optimise processes suitable for the next
‘sustainable’ century
Literature
-Den Boer J., 1998, Exergy Analysis of Kiln-3 at TPCC, MSc. report TUE.
-Hoenders 1998, Exergy Analysis as Tool for Process Optimisation in Tanzania, research report,
University of Dar Es Salaam Tanzania and Eindhoven University of Technology.
-Kotas T.J. (1995), “The Exergy Method of Thermal Plant Analysis”, 2nd
edition, Krieger publishing
Company, Malabar.
-Ptasinski and Janssen, 1998, Contents of Course ‘Exergy route towards sustainable development’,
Eindhoven University of Technology, internal memo.
-Van Schijndel, P.P.A.J., Den Boer, J., Janssen, F.J.J.G., Mrema, G.D., Mwaba, M.G. (1998),
“Exergy analysis as a tool for energy efficiency improvements in the Tanzanian and Zambian
industries”, ICESD Conference Engineering for sustainable development, July 27-29th
1998,
University of Dar Es Salaam, Tanzania.
-M.J.P. Slapak, J.M.N. van Kasteren and A.A.H. Drinkenburg, "Selection of a recycling route for
heterogeneous PVC-waste", Proceedings First International working seminar on reuse , Eindhoven,
nov. 11-13, 1996, ed. S.D. Flapper & A.J. de Ron, pag 267-275.
-Sorin M., Lambert J., Paris J. (1998), Exergy flows analysis in chemical reactors, trans IchemE, vol
76, Part A, pp. 389-395.
-Szargut J., Morris, D.R., Stewart, F.R. (1988), “Exergy Analysis of Thermal, Chemical, and
Metallurgical Processes”, 1st
edition, Springer Verlag, Berlin.
-Unanimous (1993), Environmental Building News.
-Welford R., Gouldson ,A.(1994), Environmental management and business strategy, London
Pitman.
9. Personalia
The author;
Patrick van Schijndel studied chemical engineering at the Eindhoven University of Technology and
graduated in 1994. He got his teaching degree in chemistry at Eindhoven University in 1995. Since
1996 he is doing his PhD on cleaner production at CMT, and combines this with setting up a MSc.
course in environmental technology for the University of Dar Es Salaam in Tanzania.
The co-authors;
J.M.N. van Kasteren studied chemical engineering at the Eindhoven University of Technology and in
1990 he received his PhD degree. In 1990 he worked at the Inter-University Environmental Institute
Brabant (IMB). From 1991 he works as appointed lecturer at the TUE, in the field of environmental
technology. In 1996 he was appointed director of PRI at the TUE. At PRI economic and technical
feasibility studies of the recycling of wastes are carried out.
F.J.J.G. Janssen is head of the department responsible for gasification, combustion of fossil fuels and
chemical processes at KEMA in Arnhem, The Netherlands. At KEMA he is working in the field of
research and development of gas cleanup systems for gasification of coal, heavy oils and biomass,
pyrolysis of waste and biomass, energy saving technologies and water purification.
At the TUE he is director of the Centre for Environmental Technology of the Faculty of Chemical
Engineering. CMT focuses on environmental education and environmental research.
Address:
Centre for Environmental technology
Faculty of Chemistry and Chemical Engineering
Eindhoven University for Technology
Room STO 3.25
P.O. Box 513, 5600 MB Eindhoven
The Netherlands
Phone: +31 40 247 31 97
Fax: + 31 40 245 37 62
Email: p.p.a.j.v.schijndel@tue.nl
http://www.chem.tue.nl/cmt
Published in proceedings of ENTRÉE ‘98 (Environmental Training in Engineering education), Innovation
strategies for Economy and Environment, edited by S. Poyry, J. Pringle and A. Hagstrom, 4-6 November
1998, Deventer, The Netherlands.