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Medium and large scale industries typically consume large amounts of energy, and are under pressure to increase energy efficiency and reduce energy wastages. Conventional insight-based heat exchanger network (HEN) retrofit methods typically combine graphical visualisation and algebraic tools to manage different retrofit stages. These stages often involve repetitive calculations of approach temperature, enthalpy balance and heat transfer area to assess the HEN feasibility and cost-effectiveness. This paper extends the individual stream temperature versus enthalpy plot (STEP) methodology that was introduced for HEN synthesis, to HEN retrofit. The STEP retrofit method proposed in this work enables users to simultaneously diagnose and retrofit existing HEN by using only the STEP diagram that maintains the characteristics of individual process streams. Users can graphically perform individual stream mapping without having to calculate stream enthalpies or to check for minimum temperature approach ( Δ T m i n ) violation during retrofit. Application of the new STEP retrofit method on an industrial case study demonstrates its advantages in terms of user interactiveness, simplicity of use, flexibility to customise the methodology to achieve retrofit goals of plant owners, and the least amount of efforts needed to achieve comparable results as those of established retrofit methods. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model to determine the minimum energy targets for a batch process with flexible schedule. Techniques developed for flexible-schedule batch processes typically result in nonlinear formulations. The proposed model was formulated as a mixed integer linear programming model (MILP). The model is developed based on the source-demand classification of process streams instead of the typical classification of hot and cold streams. In such classification, each stream is simultaneously treated as a source at its shifted supply temperature, and as a demand at its shifted target temperature. Such classification eliminates the model's non-linearity and reduces its complexity as well as the solution time. The mathematical model can be used to calculate the utility targets for a flexible-schedule batch process. Application of the proposed mathematical formulation demonstrates significant energy saving potential. The first illustrative example predicted a potential reduction of 11% cold utility and 14% hot utility. In the second illustrative example, up to 35% hot utility reduction and 62% cold utility reduction could be achieved. [ABSTRACT FROM AUTHOR]

Carbon dioxide emissions coming from industrial, transport, service and business activities as well as methane and nitrogen oxides from agriculture are major greenhouse gases with high global warming potentials. Modelling tools for the optimal management and reduction of greenhouse gas emissions, in particular, carbon dioxide, have received growing attention. Concurrently, complementary graphical and visualisation tools for carbon dioxide targeting, design and planning based on Pinch Analysis have evolved in line with the developments of other Process Integration tools. The application of Pinch Analysis includes the conservation of resources including heat, mass, water, gas, materials, property, solid, and more recently, power. This paper provides a comprehensive review of the development of Process Integration insight-based graphical, algebraic and numerical tools for carbon dioxide emission reduction. The key focus of the review is on methodologies that are capable of making explicit assessment on, and quantify the impact of the use of the PI tool on CO 2 reduction, covering works from 2007 (when it was initially introduced) until year 2016. The review has been categorised into supply side energy and emission planning as well as demand side and end-of-pipe energy and emission management. The aim of the review is to provide researchers, industrial planners, policy-makers and energy managers awareness of the appropriate insight-based graphical, algebraic and visualisation Process Integration tools that are available for use for carbon dioxide emissions planning and reduction. Applications of such tools is expected to enhance their conceptual understanding of the problems and ultimately help them make better decisions during the planning and management of greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

A Wastewater Treatment Plant consists of multiple equipment and processes to treat wastewater. The wastewater treatment process consumes resources and releases emissions that could potentially harm the environment. Due to the growing concern on the environmental impact of Wastewater Treatment Plants, much research has been done to assess its performance and optimize its processes towards cleaner productions. Yet to date, the study on quantifying the overall environmental performance of a Wastewater Treatment Plant has not been done. The objective of this paper is to develop a new green index as a unified overall quantitative environmental performance indicator for a Wastewater Treatment Plant and its associated processes. The developed green index is applied as an indicator to represent the multiple green elements of the treatment processes, and to benchmark the performance of the Wastewater Treatment Plant under study. The Green Index enables a facility manager to efficiently monitor, analyse and improve the performance of a Wastewater Treatment Plant in a cleaner production program. [ABSTRACT FROM AUTHOR]

The current drive towards sustainability are putting pressure on organizations worldwide to implement procedures to manage the elements of sustainability for an organisation that include emissions, effluent discharge, waste disposal and energy efficiency. Even though these green elements can be managed, monitored and analysed in an integrated manner using some common resources and information, they are typically handled piecemeal under different types of management standards; and quite often, as ad-hoc projects as opposed to programs. This paper reviews the current management systems that relate to sustainability, and proposes the development an integrated green management framework called the Sustainable Green Management System (SGMS). A systematic, integrated and efficient approach for collecting, monitoring, analysing and managing information and resources via the SGMS will not only lead to organisational sustainability, but also have the potential to save ample resources, remove significant redundancies, promote cleaner production and enhance the profitability and efficiency of an organisation. An application of the proposed SGMS framework is demonstrated on a facility management case study that uses a unified GI as an indicator for an organizational sustainability. [ABSTRACT FROM AUTHOR]

Inconsistencies of the single multi-criteria decision making (SMCD) methods in criteria weight assessment make them unreliable and have led to the wrong siting of industrial parks, which are often abandoned as brownfields that emit GHG. Eco-industrial parks (EIPs) are replacing brownfields but require robust decision-making tools to weigh and rank suitable locations for industry clusters' synergies. Integrated multi-criteria decision making (IMCDM) to address the weaknesses and strengthen the advantages of SMCDM methods, and a model to overlay criteria weights and spatial data easily and accurately were developed. The spatial criteria data for 2009 and 2019 from Tanjung Langsat Industrial Area were collected and prepared by GIS to test the SMCDM and IMCMD consistency weighting and the model resilience. The SMCDM (AHP, ANP and F-AHP) and the IMCDM weights with the 2009 criteria data identified the entire water bodies around the brownfield as suitable sites, making them inconsistent. The 2019 data with the SMCDM weights identified tiny sites as best, also making them inconsistent. The integrated hierarchy network fuzzy analytic process (HN-FAP) and the hierarchy network analytic process (HNAP) with the 2019 criteria data identified part of the water bodies as suitable making it inconsistent. The hierarchy fuzzy analytic process (H-FAP) and the network fuzzy hierarchy analytic process (NFh-AP) identified larger suitable sites without overlaps making them consistent algorithms. The H-FAP and NFh-AP procedures eliminate the weaknesses and consolidate the strengths, giving optimally consistent criteria weights. The two algorithms' consistency and the model efficiency can use different criteria weights and spatial data inputs from elsewhere for 4IR-driven EIP modelling to help brownfield-EIP stakeholders. Future research would address the reverse ranking of MCDM methods when alternatives are added or removed. • Single choice-making criteria assessment inconsistency led to wrong industrial site. • Unfavourable industrial sites have been abandoned to brownfields that emit GHG. • EIP is replacing brownfields for industry clusters, synergy and cleaner production. • Combined decision-making consistent tools and an overlay analysis model are created. • The integrated tools show clear suitable EIP sites using concentrated spatial data. [ABSTRACT FROM AUTHOR]

The operating cost of a water network can be significantly reduced via utilization of multiple water resources. In a batch process, scheduling plays a vital role towards resource conservation. This work analyzes the effect of multiple water resources on a batch water network schedule. It is proven that, in minimizing the operating cost of a batch water network, the exact schedule that leads to the minimum operating cost for multiple water resources also applies to systems involving a single water resource. This leads to a vital theorem that, once the optimum schedule for a single resource leading to the minimum operating cost is obtained, the same schedule can be applied for problems involving multiple resources. The findings in this paper have provided a simplified conceptual approach of dealing with scheduling problems with multiple water resources. Applicability of the proposed theorem is demonstrated via an illustrative example. [ABSTRACT FROM AUTHOR]

In a batch process, either direct or indirect heat integration may be employed. The former involves direct heat transfer from hot to cold process streams. In the latter, heat from a hot process stream is first transferred to an intermediate fluid where the heat is stored until it is finally transferred to a cold stream. Storage of product streams allows direct heat integration to be delayed, thereby providing an opportunity for energy conservation while avoiding the use of an intermediate fluid. This paper presents a new methodology for batch heat integration that involves the direct storage of product streams within the procedure to set the minimum utility targets. Application of the proposed methodology on illustrative examples demonstrates that significant energy reduction can be achieved by shifting product streams on the time scale. Potential reductions of 33.2% cold utility and 45.1% hot utility were estimated for the first example when the product stream was stored. Similarly, reductions of 3.5% cold utility and 6.5% hot utility were observed for a two-product batch plant when the cooling requirement for one of the products was shifted on time scale. [ABSTRACT FROM AUTHOR]

Abstract: A rice mill produces many by-products that can be further utilised into value-added products. For instance, rice bran can be further processed to produce rice bran oil. On the other hand, rice husk can be utilised as biomass in the cyclonic husk furnace or cogeneration system to supply thermal energy for paddy drying. Alternatively, rice husk can be the raw material to produce bio-char, bio-oil and biofuel. This paper presents a framework to synthesise the sustainable pathways for an Integrated, Resource-Efficient (IRE) rice mill aimed at maximising its profitability while minimising the environmental impact of its by-product utilisation. The key factors considered include the availability of resources, the cost-effectiveness of the available technology options and the trade-off between profitability and environmental impact such as global warming, photochemical ozone production and eutrophication. The developed model was applied on a case study where five different scenarios representing different economic and environmental objective functions were analysed. The proposed model allows rice millers to target for the maximum profit and synthesise the sustainable process pathways prior to the detailed design of the IRE rice mill complex. [Copyright &y& Elsevier]

Abstract: This Special Volume of the Journal of Cleaner Production focuses on the “Sustainability Engineering for the Future”. It highlights the roles of present and future engineers and provides guidelines and insights on how sustainability can be embedded systematically into all dimensions of engineering. Gone are the days when engineers only focus on technical and economic feasibility of a system design. The challenges of global warming brought about by widespread environmental pollution, resource depletion, rising human population, and multiple threats to food, water and energy securities require a paradigm shift in engineering thinking and ways to find and test solutions. The evolving engineering paradigm increasingly calls for engineers to consider the whole spectrum of sustainability i.e. from the economic, environmental, social and time dimensions. A selection of papers presented in the 6th International Conference of Process Systems Engineering Asia (PSE Asia) held in Kuala Lumpur, Malaysia from 25th to 27th June 2013 is included in this Special Volume. The papers in this volume focus upon: [(i)] Important considerations for the planning and development of sustainable products; [(ii)] Models and methods designed to support sustainable planning and management; [(iii)] Effective sustainability assessment tools and the needs for new ones; [(iv)] New approaches for improved resource management; [(v)] Illustrative future, sustainable technologies; [(vi)] Ways policies will play significant roles in promoting implementation of sustainable engineering approaches. The collection of papers as designed to provide guidelines for present and future engineers, researchers, academicians and policy makers for ways to improve current and future trends in engineering to help catalyse the transition to truly sustainable societies with improved quality of life. [Copyright &y& Elsevier]

Abstract: Rice is one of the world''s most important staple foods. Previous studies have focused on the yield improvement for an individual rice mill. There is a need to develop a framework to address the multitude of variables influencing the design of a rice mill complex, which include fluctuating thermal and electrical energy demands, diverse energy supply options, fluctuating product demands, resource availability and product degradation. The objective of this study is to develop a framework for the optimal design and planning of the product portfolio and processing route of an integrated, resource-efficient (IRE) rice mill complex. The objective function is to maximise the profitability of the rice mill by using the developed multi-period mathematical model. Sensitivity analysis was performed on the case study to evaluate the impact of fluctuating product demands, product prices and electricity cost on the production throughput, process configuration and profitability of the IRE rice mill complex. [Copyright &y& Elsevier]

Abstract: Many countries have organised energy awards as an instrument to promote energy efficiency (EE), to contribute towards energy sustainability and to provide a mechanism for organisations to continuously search, benchmark and acknowledge initiatives and best practices in EE. To be effective, an award system must be tailored towards the needs, the level of readiness and the acceptance of a nation. This paper presents a framework for implementation of a national EE award in the context of Malaysia. The current energy scenario and energy issues relevant to Malaysia are first highlighted to establish the premise for organising a national energy award. Models and success stories of EE awards in other countries are discussed as possible benchmarks for implementation. The results of a survey conducted on various energy stakeholders in Malaysia confirmed the needs, readiness and acceptance for a national EE award. A framework for the implementation of a Malaysian EE award is proposed based on the survey conducted, and on various models of energy award implementation worldwide. [Copyright &y& Elsevier]

This paper presents a new technique for simultaneous minimisation of water and energy in process plants through a combination of numerical and graphical tools. The technique consists of three steps, namely, setting the minimum water and wastewater targets; design of minimum water utilisation network, and finally, heat recovery network design. This technique offers two key advantages over current state-of-the art techniques. Firstly, it is applicable to mass transfer based and non-mass transfer based water-using operations. Secondly, it introduces a new graphical visualisation tool through a plot of temperature versus stream flowrate, termed as heat surplus diagram to guide water and energy reduction simultaneously. The heat surplus diagram provide insights on the energy demand as well as on stream matching scenarios during design of a maximum water and energy recovery network. A case study on a paper mill plant demonstrates that significant reductions in water and energy consumption can be achieved using this approach. [ABSTRACT FROM AUTHOR]

Process Integration (PI) for resource conservation has become an increasingly popular topic of research in line with growing emphasis toward circular economy and rising concern on environmental protection. PI for resource conservation in continuous processes has been relatively well-established as compared to PI developments for batch processes that have lagged behind and are gradually getting attention. This paper presents a comprehensive and up-to-date review on the development and future research direction of batch process integration (BPI) methodologies for resource conservation covering energy, water and other types of industrial resources. The BPI methodologies are categorized according to batch process scheduling flexibility. The first category is the fixed, or pre-specified schedule BPI methodologies whereby time is treated as a parameter. The second category is the flexible or variable-schedule BPI methodologies that considers time as a variable. The fixed and flexible-schedule batch processes are further sub-divided and analyzed as graphical and mathematical programming-based BPI tools. Covering literature from 2000 to 2021 that comprises more than 160 publications in over twenty years period on BPIRC progress, trends and direction, the review highlights the significant role of BPI in driving small to medium scale industries toward cleaner production and circular economy. Review on twenty year progress, direction and impact of batch process integration related to conservation of energy, water and other resources that contributes toward cleaner production and circular economy. [Display omitted] • Lack of review on batch process integration (BPI) for resource conservation. • BPI contributes toward cleaner production and circular economy. • Review classified based on resource type, schedule flexibility and type of BPI tools. • Six key areas of development covering energy, water and other materials. • Twenty year progress, direction and impact of BPI on small to medium scale industries. [ABSTRACT FROM AUTHOR]

Globally, most industrial parks that have not gone through a proper site selection process have been neglected or underutilised and such active sites tend to burn a lot of fuels and generate greenhouse gases. Technology must be used to conduct on-site investigations of the spatial and non-spatial factors of industrial parks, especially the emerging Eco-Industrial Park (EIP). The paper seeks to appraise the global application, capability and acceptability of Geographic Information System (GIS) and Multi-Criteria Decision-Making (MCDM) tools in the EIP sites selection and planning. Also, to identify the benefits of mixing MCDM tools when integrating with GIS. There have been some reviews on the use of GIS and MCDM methods, but so far, there is none on the role of GIS and MCDM methods in EIP site selection. Geospatial and MCDM tools can be used to carefully select EIP sites, where materials and energy can be shared to achieve cleaner production, reduce environmental pollution and promote sustainable development. To understand the usage of these tools and their role in the EIP site selection process, a critical review of twenty-two papers published from 2007 to 2020 indexed by Google Scholar, Springer, IEEE Xplore and Web of Science have been developed for the first time. The articles are classified based on country/region, journal of publication, year and citations of publication, the authors and technologies applied. The results show that most studies on EIP site selection come from Iran and China. The Journal of Environmental Monitoring and Assessment has the highest number of articles published at 28%. The highest number of articles was published in 2014 with 312 citations. GIS and Analytic Hierarchy Process (AHP) topped the technologies used, accounting for 42% and 24% respectively, and hybrid tools 34%. As categorised by criteria content, there was an overlap of criteria in most journals. Though, water bodies, utilities, infrastructure, and natural characteristics were prominent. Renewable energy resources were not given attention by most researchers, and risk assessment was absent from the site selection literature. A blend of traditional MCDM tools constitutes the state-of-the-art tools, and when these are combined with GIS in EIP site surveys, they execute to obtain actual results. Future EIP site selection that is integrated with risk assessment is envisioned to be industry 4.0 (4IR)-driven through a combination of GIS and artificial intelligence, and the recently developed MCDM hybrid modules. [Display omitted] • Poor site selection has led to industrial park being neglected or underutilised. • Abandoned/underutilised active industrial parks can burn fuels to cause GHG. • First time of critical review of role of GIS and MCDM tools in EIP site selection. • GIS and AHP currently mainly used for large-scale EIP site criteria selection. • EIP site choice risk study using GIS, AI and MCDM hybrid can sustain industry 4.0 [ABSTRACT FROM AUTHOR]

Abstract: Development of maximum water recovery (MWR) networks for continuous processes based on Pinch Analysis has been rather well established. In contrast, less work has been done on the water minimisation problem for batch process systems. This work presents a two-stage procedure for the synthesis of an MWR network for a batch process system, covering both mass transfer-based and non-mass transfer-based water-using processes. The first stage of the synthesis task is to locate the various network targets, which include the overall and interval-based minimum utility targets (fresh water and wastewater flows) as well as storage capacity target using the newly developed time-dependent water cascade analysis (WCA) technique. In the second stage, a new tool called the time-water network is introduced to help in the development of the MWR network to achieve the established utility targets. This new network representation has an advantage of clearly depicting the time-dependent nature of a batch water network. [Copyright &y& Elsevier]

Abstract: The first part of this series of papers (Chem. Eng. Sci. 59(5) (2004) 1009) presented a methodology for identifying the minimum utility targets for a mass exchange network (MEN) for a batch process. This paper describes the methodology for setting the minimum number of mass exchange units target and a procedure for designing a maximum mass recovery network that features the minimum utility targets. The time-grid diagram and the overall time-grid diagram that include the time dimension in network design have been introduced to provide a better representation of the mass exchange network for a batch process. The systematic network design procedure also includes a technique to simplify and evolve the preliminary batch MEN to reduce the number of mass exchangers to the minimum. [Copyright &y& Elsevier]

Heat exchanger network (HEN) retrofit plays a major role in solving environmental issues and improving plants' performance. Development of HEN retrofit graphical tools has recently focused on detailed representation of existing HEN to facilitate retrofit problem-solving. This work presents a new customised approach for HEN retrofit that uses a combination of individual stream temperature versus enthalpy plot (STEP) to map hot and cold streams, a heat exchanger area versus enthalpy (A vs H) plot to minimise the required overall heat exchanger area and graphical cost screening tool and strategies to steer and customise a retrofit design toward a desired investment payback period. Application of the new retrofit methodology on a sunflower oil production plant shows comparable energy savings and 20% shorter payback period as compared other established retrofit methodologies. Image 1 • STEP and A vs H plot are employed to perform capital-energy trade-off for HEN retrofit. • STEP indicates the multiple utilities required. • A vs H plot visualises heat exchanger area and number of additional units. [ABSTRACT FROM AUTHOR]

Hybrid power systems are becoming more popular nowadays as they provide a good transition towards renewable energy systems integration while still maintaining power sources from fossil fuels. Uncertainties based on seasonal changes, weather patterns and demand fluctuations have been considered. Disasters such as earthquake, tornado and hurricane are becoming more frequent and unpredictable as climate change is affecting major parts of the world. Safety and resilience are two important aspects that need to be taken into consideration in designing power systems due to the increase in extreme weather and natural disasters. Safety precautions are taken into consideration to withstand major damage and ensure the power system can continue to run smoothly with no or little interruption to the power supply. Previous studies focused on optimizing the cost and efficiency of the system based on season change, weather and demand fluctuations. The purpose of this research is to develop a novel methodology to design a hybrid power system considering resilience and safety aspects. This research primarily focuses on the use of Decision Matrix Risk Assessment Technique (DMRA) and Power Cascade Table (PCT) to evaluate the impact of disasters towards the power systems with and without safety consideration. The results of the case study have shown that the implementation of safety can reduce the total cost by up to USD209.3 M when catastrophic events occur. [ABSTRACT FROM AUTHOR]

Modeling tools for the optimal Hybrid Power Systems (HPS) supply planning and demand management have been relatively established. However, complementary tools that can provide planners, decizion-makers, energy managers and electrical as well as power engineers with graphical and visualization insights that are vital for better conceptual understanding of the problems, particularly at the onset of hybrid power systems planning and design, have just been developed over the last five years. This paper reviews the six-year development of the insight-based graphical and algebraic Process Integration (PI) tools for the optimal HPS supply planning and demand management, i.e., from its inception in the year 2011, until 2016. Known as the Power Pinch Analysis (PoPA), the tool has been among the next-generation PI techniques for resource conservation following the developments of the heat, mass, water, gas, materials, property, solid and carbon emission pinch analysis techniques. This paper discusses the progress, challenges and contributions of PoPA in promoting Renewable Energy (RE) utilization in HPS. Case studies on implementation of PoPA for HPS planning and design presented in the paper show encouraging improvement on HPS profitability and reliability. [ABSTRACT FROM AUTHOR]

Feed-in Tariff (FiT) has been one of the most effective policies in accelerating the development of renewable energy (RE) projects. The amount of RE electricity in the FiT purchase agreement is an important decision that has to be made by the RE project developers. They have to consider various crucial factors associated with RE system operation as well as its stochastic nature. The presented work aims to assess the sensitivity and profitability of a hybrid power system (HPS) in cases of RE system failure or shutdown. The amount of RE electricity for the FiT purchase agreement in various scenarios was determined using a novel tool called On-Grid Problem Table based on the Power Pinch Analysis (PoPA). A sensitivity table has also been introduced to assist planners to evaluate the effects of the RE system's failure on the profitability of the HPS. This table offers insights on the variance of the RE electricity. The sensitivity analysis of various possible scenarios shows that the RE projects can still provide financial benefits via the FiT, despite the losses incurred from the penalty levied. [ABSTRACT FROM AUTHOR]

This paper proposed a novel methodology to retrofit Heat Exchanger Storage Networks (HESN) of batch processes using a modified graphical retrofit tool, namely batch Stream Temperature Enthalpy Plot (batch STEP). Unlike other graphical retrofit tools, batch STEP maintains individual characteristic of process streams as well as serves as the one-stop retrofit tool to retrofit direct and indirect HESN simultaneously. The conventional batch heat integration typically aimed to synthesise new Heat Recovery Loops (HRLs) for heat recovery enhancement without exploiting the benefits of reusing existing HRLs in saving the additional volume of heat storage units (HSUs) and space allocated for retrofit. Thus, this paper extends the STEP continuous retrofit methodology to batch processes by introducing a batch STEP diagram for identification of the potential process streams to be integrated into existing HRLs and potential modifications of existing HRLs operating temperature. The methodology also introduces HRL– problem table algorithm (HRL-PTA) and heuristics to target the maximum indirect heat recovery and integrate process streams into the existing HRLs systematically. The methodology proposed achieves plant savings of 23.9%–60.0% for hot utility, 25.9%–42.2% for cold utility and a reduction of 6.3%–8.1% for additional volume of HSUs required in two illustrative case studies. [Display omitted] • An extended STEP graphical tool for retrofitting HESN of batch processes. • Diagnosis of process streams to be integrated into existing heat recovery loops (HRLs). • Diagnosis of potential modification of existing HRLs operating temperature. • The maximum indirect heat recovery by existing HRLs is targeted. • Integration of heat supply and load into existing HRLs is guided. [ABSTRACT FROM AUTHOR]

Renewable energy is crucial to reducing climate change as it replaces fossil fuel-based energy sources partially. However, renewable energy facilities are highly dependent on climate conditions. There have been few studies in Malaysia focusing on the impacts of extreme temperature and precipitation on energy systems. None of the studies used the risk assessment method to examine the effects. This research aims to study the possible risks associated with common renewable energy systems in Malaysia (solar photovoltaic, anaerobic biogas system, biomass, and hydropower) using a risk matrix approach. The mitigation action plan to reduce extreme weathepact on each energy system will also be presented in this study. Three extreme temperature and precipitation scenarios were used to explore the potential impacts on infrastructures, energy resources, power capacity, and efficiency of solar photovoltaic systems, hydropower, biomass, and biogas power plant. The trend of daily temperature and precipitation in Malaysia from 1970 to 2070 is also presented. By 2070, Malaysia will be experiencing greater change in rainfall, as well as warmer temperatures and more droughts. Results of the study show that biomass is the most vulnerable to extreme temperature and precipitation. • Risk assessment on solar PV, hydropower, biomass and biogas using a risk matrix approach were presented. • Malaysia will experience a higher change in rainfall, warmer and more droughts by 2070. • Biomass is the most vulnerable to extreme temperature and precipitation. [ABSTRACT FROM AUTHOR]

Abstract: Supertargeting based on composite curves (CC) is widely used to determine the optimum approach temperature (ΔT min) that yields the minimum total cost for heat exchange networks (HEN). Supertargeting using CC has two key limitations. Firstly, the HEN area calculations are drastically simplified through the assumption that CC segments may be considered as pseudo-single hot and cold streams exchanging heat via only one exchanger that is governed by a single cost correlation. Secondly, the current Supertargeting approach of considering only one hot and one cold utility level may lead to a crude estimation of the total HEN cost and the optimum ΔT min. This work presents the stream temperature vs. enthalpy plot supertargeting (STEPS) method that overcomes these limitations. This paper proves that supertargeting based on CC can lead to up to 50% error in the total cost target and poor ΔT min estimations. [Copyright &y& Elsevier]

The development of biomass-based cogeneration energy systems in Malaysia is progressing to meet the circular economy concept and sustainability goal. This comprehensive review aims to report recent advancements in biomass-based cogeneration/biomass co-firing technology in Malaysia correlated with the optimization modeling role. First, this work presents the outlook and current scenario of cogeneration systems in Malaysia by observing performance and the challenges confronted by the technologies. Next, investigation of technical issues concerning the key players of the technologies and the biomass supply chain. This work had prepared using quantitative content-based analysis-meta-analysis. The practical implication of this review enables a complex optimization model that integrates biomass-based cogeneration and biomass supply chain considering economic and environmental viability. It will further enhance progress toward the Malaysian "Industry 4.0-driven" energy initiative. A novel optimization model grounded on Industry 4.0 parameters will foster new opportunities for researchers. [Display omitted] • The biomass cogeneration outlook, current scenario, successes and regional challenges in Malaysia. • Technical and operational issues of the biomass based-cogeneration and biomass co-firing. • Role of optimization modeling in the biomass based-cogeneration, biomass co-firing and biomass supply chain advancements. • New directions and the potential of those technologies in the era of Industry 4.0 [ABSTRACT FROM AUTHOR]

Sustainability and Industrial Ecology (IE) are the main drivers of industrial symbiosis (InSys) and eco-industrial parks (EIPs). InSys, therefore, extends the idea of industrial ecology (IE) to the industrial sector by adopting a resource-efficient approach where one firm uses the unused or residual resources (materials, energy, water, assets, logistics, and expertise) of another firm. The aim is to enhance a sustainable and cleaner production in an environmentally friendly way, one in which generation of wastes and emission of greenhouse gases (including CO 2) is minimized. Although previous literatures have investigated existing InSys tools, the utilization of the process integration (PI) tools for InSys design and planning has mostly operated in isolation of each other and thus concentrated on individual resources which makes the it hard for InSys designers to select the best tools. Furthermore, there is a dearth in research on comprehensive and integrated resource optimization, which considers the integration of all resources (such as energy, water, power, carbon and wastes) within InSys simultaneously. Therefore, this study investigated and surveyed available literatures in order to identify and develop a more comprehensive description of InSys tools, through the analysis of related methodologies and applications by integration of various resources optimization tools together for the design and establishment of EIPs. The tools are inclusive of both insight-based Pinch Analysis and mathematical optimization models approaches. The review also conducted a bibliometric analysis of some keywords using Scopus over a span of twenty-two years (1998–2019). Through the insights and understanding gained from the review, designers will be more equipped to make a more informed choice of working tools to utilize. Finally, suggestions were offered on some tools that will enhance the integration of eco-industrial parks to minimize fresh water/wastewater, minimize fuel use and reduce GHGs emissions and the minimization of cooling, heating and power requirements in Total Sites. The review of integrated resource optimization tools is then followed by identifying future research directions and development. Image 1 • Process integration (PI), mathematical optimization (MO) methods and other models are reviewed in this work. • A bibliometric analysis of industrial symbiosis (InSys) concept and tools are conducted. • A better understanding of InSys tools for the design and establishment of eco-industrial parks (EIPs) is enhanced. • A valuable insight for researchers, planners and other stakeholders. [ABSTRACT FROM AUTHOR]

Recent developments of Pinch-based heat exchanger network (HEN) retrofit methodologies mainly focus on improvement of HENs, and much less on seeking opportunities to enhance energy efficiency of processes via process and utility changes. Conventionally, Pinch-based retrofit methodologies employ Composite Curves (CC) and Grand Composite Curve (GCC) to screen for process changes opportunities. However, CC and GCC cannot directly indicate the specific individual process and utility streams to undergo process changes as the streams are composited within the CC and GCC. This work extends the use of individual stream temperature versus enthalpy plot (STEP) to enable designers to scope, screen and selectively customise structural and parametric process and utility changes for existing HENs. STEP diagram can be used to graphically customise retrofit options involving beneficial process utility changes for an existing HEN, and improve overall process energy efficiency. Application of STEP diagram on an illustrative case study and an existing crude oil refinery plant show that STEP diagram enables a designer to graphically pinpoint the exact individual process streams to undergo process and utility changes based on the individual stream profile and to determine the optimal load and levels of multiple utilities required, as well as the limit of process changes that can be performed. Results of this work show that on top of performing HEN retrofit, customised process and utility changes can result in an additional 18.4% hot utility reduction. Image 1 • CC and GCC cannot identify specific individual process stream for process changes. • New methodology uses STEP for structural and parametric changes of existing HEN. • Proposed methodology is applied on an existing crude oil refinery plant. • Additional 18.4% Q H reduction is achieved by process change. • Large savings can be achieved by process change with little or no investment. [ABSTRACT FROM AUTHOR]

The difference in electricity pricing based on the time of power use has led to load shifting from peak to off-peak hours in hybrid power systems (HPS). Apart from optimising electricity cost, shifting of the load may also change the capacity of storage in the system. Power Pinch Analysis has been recently applied to guide load shifting aiming to minimise the cost of electricity, considering the peak and off-peak electricity pricing. The HPS was assumed to be ideal with 100% efficiency, which is not achievable in actual operational condition. This work extends the study by scrutinising the effects of peak-off-peak load shifting on the capacity of storage in HPS. The effects of energy losses due to the inefficiency during power conversion, transfer and storage in the HPS are considered in developing shifting heuristics to ensure optimal storage size is achieved. Implementation of the proposed load shifting strategy on a case study demonstrates that a reduction of up to 30% in the storage size can be achieved, which led to a minimum storage cost. The distribution of peak hours' demand to off-peak hours also successfully provide significant savings in the electricity bill. [ABSTRACT FROM AUTHOR]

Development of Power Pinch Analysis (PoPA) for the design and optimisation of Hybrid Power Systems (HPS) is steadily progressing. Even though PoPA has been developed for a wide range of applications in HPS design and analysis, the economic aspect still needs more attention. Screening of various renewable energy (RE) technologies in HPS is crucial as different technologies may have different cost and efficiencies, and affect the overall system economics. This work presents a novel framework for the design of a cost-effective HPS by incorporating PoPA with a cost-screening tool known as the Systematic Hierarchical Approach for Resilient Process Screening (SHARPS). SHARPS, which was originally developed to screen various process changes options in water networks is adapted to perform economic analysis and RE technology screening in power networks. Two strategies namely substitution and intensification have been proposed, in order to customise a cost-effective HPS. The presented framework provides a handy and effective measure to visualise the trade-off between the performance and cost of various potential RE technologies for HPS. Application of the framework on a case study demonstrates that the HPS design has been successfully customised with the RE technology scheme and capacity acceptable to the owner, while meeting its targeted payback period of 10 y. [ABSTRACT FROM AUTHOR]

This work presents a holistic approach for design of Cost-Optimal Water Networks (CWN) that considers the economics while exploring all water minimisation options in line with the water management hierarchy (WMH). Two stages are involved in analysing the model i.e., the freshwater saving mode (FWS-mode) and the economic mode (E-mode). The first stage applied the mixed integer linear program (MILP) formulation that yielded some initial values for the second stage. In the second stage, the model was formulated as a mixed integer nonlinear program (MINLP) that was used to optimise an existing water systems design. The novelty of the model lies in the simultaneous considerations of all levels of water management hierarchy (i.e. elimination, reduction, reuse, outsourcing and regeneration) and cost constraints in selecting the best water minimisation schemes that resulted in the maximum net annual savings at a desired payback period. The model is applicable for systems involving multiple contaminants, and is capable of predicting which water demand should be eliminated or reduced; how much external source is needed; which wastewater source should be reused/recycled, regenerated or discharged; and finally specify the minimum water network configuration for maximising the net annual savings at a desired payback period. The model has been successfully applied on case studies involving a building (Sultan Ismail Mosque, UTM) and an industrial process plant (a chlor-alkali plant). [ABSTRACT FROM AUTHOR]

This paper presents a systematic technique to select the optimal design target for the heat exchanger network ( HEN ) synthesis by using a new trade-off plot which considers aspects of design, controllability in terms of steady state flexibility and sensitivity analysis, and cost. By selecting the HEN design target according to this guideline, the designer is able to predict the design, operability, and controllability of the designed HEN at the beginning of the synthesis stage. In this study, the HEN design target that needs to be optimized is the value of the minimum temperature difference ( Δ T min ). In traditional HEN synthesis, designers only consider the trade-off between capital and operating costs in selecting the best Δ T min . As a result, the HEN design at the selected Δ T min may not be optimum in terms of steady state controllability. In addition to considering the capital and operating costs, the proposed new method provides additional design insights in terms of energy recovery, operability, controllability (steady state) through the flexibility and sensitivity. The proposed trade-off plot allows designers to choose the most suitable design target either for the purpose of improving a network’s energy recovery and/or controllability. A case study has been applied to test the capability of the new proposed trade-off plot. The results show that Δ T min = 40 °C is the optimal design target to synthesize flexible and operable HEN . [ABSTRACT FROM AUTHOR]

Pressure drop is an important consideration in Total Site Heat Integration (TSHI). This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN) synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER) targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%. [ABSTRACT FROM AUTHOR]

In this study, the equilibrium and non-equilibrium models for CO 2 absorption from natural gas stream by DEA-promoted potassium carbonate solution in a tray column were developed and compared with each other. The Electrolyte NRTL thermodynamic model was utilized to calculate the activity coefficient in the liquid phase, and the SRK equation of state was used for the gas phase. The non-equilibrium model was based on the two-film theory, and the effect of film discretization was examined. The equilibrium model was based on the theoretical number of stages combined with the concept of Murphree efficiency from 0.1 to 0.3 for three stages in the lower section of the column and 0.4 from stage 4 onwards. A thermodynamic study was performed to describe the equilibrium behavior of the solvent. All the necessary reactions in the liquid phase were considered in all simulations. The models were validated by comparing the obtained results with the published experimental data. Results of absorber column simulation show that the non-equilibrium model gives a better prediction of the temperature and concentration profiles as compared to the equilibrium model. [ABSTRACT FROM AUTHOR]

Abstract: Mathematical programming techniques have been widely used to solve water minimisation problems. Yet, to date, there is lack of research on water minimisation for fixed schedule and cyclic operation batch processes that also targets the minimum storage capacity as well as inter-connections, and considers mass-transfer based (MTB) and non-mass transfer-based (NMTB) operations, for problems with multiple contaminants. In this study, a four-stage mathematical model is formulated to address the aforementioned problem, by considering water minimisation options within a Water Management Hierarchy (WMH). The developed model was employed on an urban and an industrial facility to demonstrate the effectiveness of proposed model to solve the minimum water network with minimum storage tank capacity and network inter-connections. For the urban facility case study involving a mosque, the maximum potential freshwater and wastewater reductions are 99.89% and 65.7%. Setting the minimum number of inter-connections (MNI) as the objective function has further reduced the MNI by 13%. For the industrial case study, the maximum potential freshwater and wastewater reductions are 59.53% and 16.43%. Imposing the MNI constraint as the objective function further reduced the number of inter-connections by 20.83%. [Copyright &y& Elsevier]

Abstract: Total Site Heat Integration (TSHI) is a technique of exchanging heat among multiple processes via a centralised utility system. An analysis of the integrated multiple processes, also known as the Total Site (TS) system sensitivity, is needed to characterise the effects of a plant maintenance shutdown, to determine the operational changes needed for the utility production and to plan mitigation actions. This paper presents an improved Total Site Sensitivity Table (TSST) to be used as a systematic tool for this purpose. The TSST can be used to consider various ‘what if’ scenarios. This tool can be used to determine the optimum size of a utility generation system, to design the backup generators and piping needed in the system and to assess the external utilities that might need to be bought and stored. The methodology is demonstrated by using an Illustrated Case Study consisting of three processes. During the TS normal operation, the Total Site Problem Table Algorithm (TS-PTA) shows that the system requires 1065kW of High Pressure Steam and 645.5kW of Medium Pressure Steam as the heating utility, while for the cooling utility, 553.5kW of Low Pressure Steam and 3085kW of cooling water are required. The results of the modified TSST proposed that a boiler and a cooling tower with the system design requiring a maximum capacity of 2.172MW of steam and 4.1865MW of cooling water are needed to ensure an operational flexibility between the three integrated processes. [Copyright &y& Elsevier]

SUMMARY A new and very promising application of auto-thermal reactors is the coupling of endothermic and exothermic reactions where the product of the endothermic reaction is the desired one. Therefore, in this work, a reactor in which oxidative coupling of methane (OCM) and steam re-forming of methane (SRM) reactions take place simultaneously was modeled. The results were obtained in a wide range of different conditions such as inlet feed, inlet temperature, portions of OCM and SRM catalysts, and inlet velocity. In selection of the catalysts, more attention was drawn to prevent re-forming of OCM products. The main parameters of each reaction under different conditions such as conversion of the feed components, products selectivity and yield, temperature in the length of reactor, and component's concentration in the reactor were considered in course of this study. The results revealed that simultaneous OCM and SRM reactions in one reactor will tend to be auto-thermal, and the waste of energy will be reduced. The results also show that complete conversion of water and majority of methane and oxygen will decrease the amount of unwanted products at the reactor's discharge-a constraint that exists in single reactors of each reaction specially OCM. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Azeotropic and extractive distillation techniques used to separate azeotropic mixtures are among the most challenging separation processes in the chemical industry. In this work, an innovative distillation technique which employed ultrasonic waves was proposed to intensify the conventional multi-column azeotropic distillation method into a single-column alternative. The effects of ultrasonic intensity on the vapor-liquid equilibrium (VLE) of methyl-tert-butyl-ether (MTBE)-methanol was investigated at 50, 100, 200, and 250 W/A·cm2 and at a fixed frequency of 40 kHz. Studies were also done to examine the effects of ultrasonic frequency on the VLE data at 25 and 68 kHz frequencies. It was found that ultrasonic waves at 50 W/A·cm2 intensity and 25 kHz frequency gave the highest relative volatility (α) at 2.654 and completely eliminated the MTBE-methanol azeotrope, thereby allowing highly pure MTBE to be recovered in just a single distillation column. The results revealed that ultrasonic waves had the potential to favorably manipulate α, and hence, the VLE of an azeotropic mixture. [ABSTRACT FROM AUTHOR]

The hybrid power system (HPS) that integrates diesel/biodiesel plant with renewable energy (RE) technologies has become increasingly popular to alleviate greenhouse gases emissions issue of the sole diesel/biodiesel power system. Integrated diesel-RE power system offers cleaner power supply while minimising cost of diesel fuel and diesel system maintenance. The use of Power Pinch Analysis (PoPA) method for the integration of diesel plants and RE systems into HPS with the objective to minimise fuel requirement and operational time of diesel generator has been presented. This work aims to achieve the same objective via probability theory utilisation, to simplify the PoPA procedure involving the matching of various routes for power flows. The extended technique called the Probability-Power Pinch Analysis (P-PoPA) can give accurate results as those established from the PoPA method within a shorter analysis time because it replaces the tedious manual matching step with correction factors. All probable routes of power from RE and diesel generators to demands are considered in computing the correction factors, in order to target the minimum diesel power in the integrated system. The result of a Case Study demonstrates that 19% saving in diesel fuel consumption can be realised if the present diesel station is supported with renewable solar power in an HPS. The result of the P-PoPA method is accurate with a very minor deviation to that from the conventional PoPA technique. [ABSTRACT FROM AUTHOR]

Future 100% renewable energy systems will have to integrate different sectors, including provision of power, heating, cooling and transport. Such energy systems will be needed to mitigate the negative impacts of economic development based on the use of fossil fuels, but will rely on variable renewable energy resources. As two-thirds of global greenhouse gas emissions can be attributed to fossil fuel combustion, decarbonization of energy systems is imperative for combating the climate change. Integrating future energy systems with CO 2 capture and utilization technologies can contribute to deep decarbonization. As these technologies can be operated flexibly, they can be used to balance the grid to allow for high levels of variable renewable energy in the power mix. The captured CO 2 can be either utilized as a feedstock for various value-added applications in the chemical industry and related sectors such as the food and beverage industries. This paper reviews the state-of-the-art literature on CO 2 capture and utilization technologies, with an emphasis on their potential integration into a low-carbon, high-renewables penetration grid. The potential market size for CO 2 as raw material is also elaborated and discussed. The review paper provides an insight to the development and the technological needs of different energy system sectors, as well the limitations, challenges and research gaps to the integration of the variable renewable energy sources and flexible carbon capture and utilization technologies. Image 1 • Integration of renewable energy systems and carbon capture technologies is needed. • Flexible carbon capture and utilization technologies are needed to meet energy demands. • Carbon capture technologies stabilize volatile energy systems by utilizing excess energy. • Captured carbon dioxide can be used directly, or as raw material for chemical products. [ABSTRACT FROM AUTHOR]