Recent advances in resource conservation and planning-a review
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ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERINGAsia-Pac. J. Chem. Eng. 2011; 6: 689695Published online 28 April 2011 in Wiley Online Library(wileyonlinelibrary.com) DOI:10.1002/apj.587
Special theme review
Recent advances in resource conservationand planning a review
Sharifah Rafidah Wan Alwi,1 Zainuddin Abd Manan1* and Jir Jaromr Klemes2
1Process Systems Engineering Centre (PROSPECT), Universiti Teknologi Malaysia, UTM Skudai, Johor Bahru, Malaysia2Centre for Process Integration and Intensification CPI2, Research Institute of Chemical and Process Engineering, Faculty of Information Technology,University of Pannonia, Veszprem, Hungary
Received 24 January 2011; Revised 6 March 2011; Accepted 8 March 2011
ABSTRACT: This paper provides a dedicated overview of the Special Issue of Asia Pacific Journal of ChemicalEngineering. It highlights the current issues and challenges surrounding Resource Conservation and Planning andprovides an update to practitioners, researchers, academicians and policy makers on some recent technologicaldevelopments in this area. This overview includes a compilation of ten papers that focus on ways to:
(1) select the best resource conservation and planning software tools;(2) design sustainable products and process systems that utilise less resources;(3) minimise the demand for fresh resources by converting wastes to resources;(4) assess the environmental impacts of products and processes;(5) identify, monitor and manage river pollutions.
2011 Curtin University of Technology and John Wiley & Sons, Ltd.
KEYWORDS: process integration; optimisation; resource; conservation; sustainability; pinch analysis
Growing global concern on sustainability hasencouraged extensive resource conservation effortsworldwide. The Oxford Dictionary Website definesresource as a stock or supply of money, materials, staffand other assets that can be drawn on by a person ororganisation in order to function effectively. Materialresources conservation in particular can be defined asprotection and rational use of natural resources includ-ing minerals, fossil fuels, water, flora and fauna. Thespecial emphasis of this review paper is for the con-servation and sustainable use of material resources.There have been numerous definitions on sustainabilityand, in particular, sustainable development. The Uni-versity of Reading presented various definitions usedby IUCN, UNEP and WWF concerning sustainabledevelopment, sustainable growth and sustainable usethat have been applied interchangeably as if their mean-ings were the same. Indeed, they are different. Sus-tainable growth is a contradictory phrase as nothing
*Correspondence to: Zainuddin Abd Manan, Process Systems Engi-neering Centre (PROSPECT), Universiti Teknologi Malaysia,Malaysia. E-mail: firstname.lastname@example.org
physical can grow indefinitely. Sustainable use is onlyapplicable to renewable resources. Sustainable devel-opment is used in this strategy to mean improving thequality of human life whilst living within the carryingcapacity of the ecosystems.
HMSO proposes that most societies want toachieve economic development to secure higher stan-dards of living, now and for future generations. Theyalso seek to protect and enhance their environment, nowand for their children. Sustainable development tries toreconcile these two objectives. DEFRA provided thefollowing definitions and thoughts: The goal of sus-tainable development is to enable all people throughoutthe world to satisfy their basic needs and enjoy a betterquality of life without compromising the quality of lifeof future generations. The goal of sustainable develop-ment is to ensure mankind is able to satisfy its basicneeds while making sure future generations can alsolook forward to the same quality of life. Sustainabledevelopment recognises the interconnections betweensociety, the environment and economy and aims to findsolutions that deliver benefits for all of these while min-imising negative impacts.
Rapid population growth and technological develop-ments have increased the rate of resource consumption
2011 Curtin University of Technology and John Wiley & Sons, Ltd.Curtin University is a trademark of Curtin University of Technology
690 S. R. W. ALWI, Z. A. MANAN AND J. J. KLEMES Asia-Pacific Journal of Chemical Engineering
and contributed to the diminishing supply of worldsprecious resources including fossil fuels and water.Industrialisation has improved the quality of life but hasalso been attributed as causes of for global warming andextinction of some flora and fauna due to widespreadpollution in the form of gaseous emissions and solidwastes, as well as discharges of wastewater and chem-icals. To achieve sustainable development that benefitsthe current generation, while maintaining the capacityto meet the needs of future generations, conservation aswell as appropriate planning and management of nat-ural resources needs to be carefully considered. Thesetopics have been part of the main action agenda forresearchers and industrial practitioners.
Dov et al . summarised the steps towards buildinga sustainable society as follows:
(1) Diversification of energy sources and supply chains;regional energy sustainability zones and interzoneintegration.
(2) The mass storage of energy especially of electric-ity and heat/cold.
(3) The energy efficiency and energy saving attitudebeing accepted as a priority by society.
(4) The change of the societal approach away fromwasting energy.
(5) Sustainable energy solutions for transport technology, management and societal accep-tance.
(6) Sustainable energy solutions for developing coun-tries.
(7) Sustainable energy for securing fresh water for theworlds growing human population.
Chemical engineers have a key role to play in findingsolutions to conserve resources through creation ofsustainable systems that are resource-efficient, cost-effective, safe and environment-friendly.
Rapid advances indicated the need to compile andreview the latest resource conservation and planningresearch efforts, and inspired the creation of this SpecialIssue. After a thorough screening and review process,we hereby present a collection of ten papers coveringthe most recent developments in various chemicalengineering resource planning and conservation topics.The range of issues addressed by the ten papers includesthe following questions.
(1) Which software should a researcher or practitioneruse for resource integration and planning fromthe many and diverse software packages availableworldwide?
(2) What is the best arrangement of heat exchangesequences, either in series or parallel, to minimiseequipment and operating costs and at the sametime maximise heat recovery?
(3) How to design a flexible heat exchange networkthat can take into consideration process uncertain-ties?
(4) How can heat be optimised for a biogas productionsystem?
(5) How does the fluid distribution system affect heatexchanger performance?
(6) How can exergy analysis be used to reduce sig-nificant losses in energy, and improve equipmentperformance?
(7) How to design an optimal water network involvingmultiple contaminants for global water operationsin the urban and industrial sectors?
(8) How can pinch analysis be adapted to set resourcetargets and design a recovery network for solidwaste systems such as for paper recycling?
(9) Can unburned carbon in ash be separated andreused as value-added products?
(10) How can a life cycle inventory be performedwhen multiple products, and uncertainties in datasources, are involved?
(11) How to identify pollution sources along a river,and what are their impacts to the river ecosystem?
AN OVERVIEW OF PAPERS IN THIS SPECIALISSUE
This Special Issue can be divided into four researchgroups as described below:
(1) The first group of papers highlights progressin process integration, modelling and optimisa-tion that can help minimise resource usage (e.g.energy, water and trees) and reduce waste discharge(e.g. emission, wastewater and paper) via efficientproduct and process design. This group also cov-ers available tools such as software, models andheuristic techniques.
(2) The second group emphasises on the transformationof waste to wealth by converting it into usefulproducts.
(3) The third group covers advances in life cycleassessment (LCA) as a useful tool for evaluating theenvironmental impacts of a product or process.
(4) The fourth group focuses on identification of pollu-tion sources for proper planning and managementof river water quality.
Process integration, modellingand optimisation
There are several common definitions of process inte-gration, and the special cases involving heat, and/ormass/water integration. Among the most recent defi-nitions are those by Klemes, Smith and Kim and
2011 Curtin University of Technology and John Wiley & Sons, Ltd. Asia-Pac. J. Chem. Eng. 2011; 6: 689695DOI: 10.1002/apj
Asia-Pacific Journal of Chemical Engineering RECENT ADVANCES IN RESOURCE CONSERVATION AND PLANNING 691
Klemes et al . El-Halwagi defines process integra-tion as a holistic approach for process design, retrofitand operation which emphasises the unity, as opposed tothe components or parts, of a process. Process integra-tion provides a unique framework for designers to fun-damentally understand the global insights of a process;methodically determine the achievable performance tar-gets and systematically make decisions to achieve thesetargets. Process integration methodology involves threekey components, namely synthesis, analysis and optimi-sation with recent overviews provided by Friedler.[20,21]
These three major steps are crucial to achieving sus-tainable process development and necessary improve-ments in order to conserve resources in addition toreducing environmental impacts, capital costs and oper-ating costs. Seven of our selected papers relate toadvances in process integration, modelling and optimi-sation.
Process integration, modellingand optimisation software toolsPaper 1 provides a comprehensive review on processintegration, modelling and optimisation software toolsand describes specific software features, their advan-tages and detailed applications based on the authorsexperiences. The software tools for process integrationare specifically those based on heat and water pinchanalysis. The tools involved optimum utility selectionfor heat and water minimisation in individual processesand total site, for grassroots as well as retrofit cases. Thesoftware tools for balancing reconciliation and for pro-cess flowsheet simulation to generate sustainable designand perform energy savings analysis are also evaluated.There are also tools for energy saving and pollutionreduction. The paper includes a summary of the soft-ware tools evaluated, and some projections of futuretrends for process software tools. They concluded thatfuture researchers will focus on building computer hard-ware, integrate systems across fields, collaborate andnetwork in real time mode via the Internet, developdynamic and control simulators, extension tools andfaster as well as more efficient optimisation and syn-thesis methods.
Energy conservationFollowing an increased awareness of sustainabilityissues, many companies have started to emphasise onenergy management. In terms of priority, the mostbasic and widely practiced step in managing energyusage entails promoting energy conservation measuresthrough implementation of various good-housekeepingpractices at little or no investment. The next stage isencouraging the use of energy-efficient systems andequipment, such as installing heat recovery systems,that requires some investment. Investment in renewableenergy resources, such as solar and biogas, should be
considered once energy conservation and improved effi-ciency have been achieved. Recent advances in energyconservation and management methods are discussed infour papers.
In cases when fuel cost is low, it may not be worth-while to recover heat from hot streams at temperaturestypically below 150 C. However, when the cost of fuelis high, heat recovery from heat sources at such tem-peratures may become desirable. Paper 2 presentsa method to determine the best arrangement of heatexchange sequence to minimise equipment and oper-ating costs, designating the system as low temperatureheat exchanger network (LTHEN) where water is gen-erally used as a circulating medium. Flexibility to caterfor process uncertainties such as varying feed stockcompositions, deteriorating heat transfer capacity (dueto fouling and changes in flow conditions as a resultof seasonal or operational requirements) are the salientfeatures of the method.
Agro-industries and animal by-products produce largequantities of organic wastes that are not only pathogenicbut also contribute to greenhouse gas emissions.Through anaerobic digestion, these wastes can be con-verted to biogas which can be used as a source of fuelfor heat and power generation. Paper 3 presents anMINLP model for simultaneous heat integration, com-bined electricity and heat production, as well as syn-thesis of a biogas process. The model which includesselection of different auxiliary facilities (e.g. differentsupplies of inlet wastes, water supplies unit, wastewatertreatment system, transportation of industrial wastew-ater, etc.) is an extension of Drobez et al . andDuran and Grossmanns model. The objective func-tion of the model is to maximise the net present worth(NPW) while minimising the utility demands, capitaland operating costs and maximising biogas and otherby-products generated. A meat company is used as acase study to demonstrate application of this model. Useof this model yields the twofold benefit of improvinga companys profitability while mitigating the environ-mental impact of harmful organic and animal wastesby converting them into valuable products such asbiogas.
Research on heat exchanger networks has focusedmainly on targeting and synthesis of maximum heatrecovery networks. Paper 4 emphasises the impor-tance of optimising the detailed design of individualheat exchangers after targeting and network design havebeen performed. The authors propose a formula for thecoefficient of static regain for parallel flow systems con-taining linearly tapered manifolds with rectangular crosssections connected by double U-tubes. To further fine-tune the formula, physical experiments are suggested.Other manifold profile types with nonlinear change ofcross-sectional width and height, and the assumption ofuniform distribution of compressible fluids, also requirefurther research.
2011 Curtin University of Technology and John Wiley & Sons, Ltd. Asia-Pac. J. Chem. Eng. 2011; 6: 689695DOI: 10.1002/apj
692 S. R. W. ALWI, Z. A. MANAN AND J. J. KLEMES Asia-Pacific Journal of Chemical Engineering
One of the most effective ways to reduce energy isby focusing attention on any equipment incurring highenergy losses. Exergy analysis has been widely...