This work discusses a crucial activity for Heat Integration (HI): Data Extraction (DE). Overall, ... more This work discusses a crucial activity for Heat Integration (HI): Data Extraction (DE). Overall, data acquisition is a complex process involving many stages and stakeholders. The paper analyses the treatment of DE in the published literature. The analysis established that many publications just present the results from already performed DE and others limit the provided reasoning only to a few key issues. Further, the importance of the preservation of data integrity and semantics is highlighted. This can be done by documenting the reasoning and the choices made during DE, as well as distributing the DE reasoning between the general discussion and stream-specific information placement into the Process Streams Table for HI, preserving the context. The approach is illustrated on a published example.
The opportunistic maintenance (OM) approach allows exploiting the stoppage for performing additio... more The opportunistic maintenance (OM) approach allows exploiting the stoppage for performing additional maintenance actions alongside those planned, to save cost and time. This study aims to propose a graphical approach to identify the optimal maintenance grouping strategies in an operating process. The failure of a specific component is predicted by using the statistically-derived probability distribution function that reflects its time-variant failure behaviours. The periodic maintenance schedule is first derived, and the system failure likelihood is predicted within each time interval. The failure of one of the component creates an opportunity to reschedule maintenance activities, which can be carried out while replacing the failed components. The expected cost to mitigate the failures (‘Sinks’) can be reduced by the expected maintenance reschedule cost savings (‘Sources’) based on the derived schedule previously. In this work, Pinch Analysis is used as a targeting tool to determine...
31st European Symposium on Computer Aided Process Engineering, 2021
The decisions on synthesising a process network are often to optimise the payback periods based o... more The decisions on synthesising a process network are often to optimise the payback periods based on investment cost. In addition to the core investment and the cost of used resources, the long-term reliable operation of the process is also crucial. Given available states and technologies of the assets, this study aims to identify the long-term optimal asset planning policy. Markov Decision Process (MDP) is a promising tool in identifying the optimal policy under different states of the assets or equipment. The failure probability of the unit is modelled with the ‘bathtub’ model and each of the condition states are incorporated in the MDP. The decisions to implement the redundant units in the process with variety of technologies are allowed. This paper applied the MDP into an equivalent Mixed Integer Non-linear Programming (MINLP) to solve for the optimal long-term assets decision and the maintenance policy. The applicability of the method is tested on a real case study from Sinopec P...
Sophisticated approaches have been proposed to reduce material utilities such as water and hydrog... more Sophisticated approaches have been proposed to reduce material utilities such as water and hydrogen by designing resource allocation networks. For resource targeting, graphical methods have been developed for single quality material recycle/reuse. Up to now, systematic approaches to targeting fresh resources in a multi-contaminant material recycling network ahead of the detailed design are not readily available. This work presents a rigorous resource targeting procedure in the domain of multiple constraints (e.g. multi-contaminants). The problem is formulated as a resource-allocation superstructure model and modified to determine the model characteristics and obtain the optimal solution. These conditions are then transformed into a table and graphical forms to identify the minimum resource target. By inferring from the mathematical formulations, multiple cascades with individual contaminant/quality have to be analysed sequentially. The main issues are the identification of the prope...
This article evaluates the processing of Municipal Solid Waste (MSW) and its contribution to sust... more This article evaluates the processing of Municipal Solid Waste (MSW) and its contribution to sustainability from the viewpoint of its net exergy balance. The evaluation follows the recent framework for estimation of Exergy Footprint and Exergy Profit for a given Process System. The method evaluates the Exergy Assets and Liabilities, estimating the Exergy Profit as the balance of these two. The concept of avoided exergy by substituting the useful chemical to its primary production, similar to the concept of avoided emission is also proposed in this work. The obtained estimate is the specific contribution of the considered MSW processing system. For estimating the overall impacts, the obtained Exergy Profit has to be added to the contributions of the potential upstream and downstream processes. The results show the potential value that can be obtained and sustainability contribution to be achieved by the extraction of useful chemicals from waste and waste-to-energy conversion. The che...
This work addresses the internal and Total Site Water Network design with water mains. A Material... more This work addresses the internal and Total Site Water Network design with water mains. A Material Recovery Pinch Diagram is used for freshwater targeting and a Water Integration Network design with...
The Circular Economy principle has to be applied more vigorously to tackle the rapid depletion of... more The Circular Economy principle has to be applied more vigorously to tackle the rapid depletion of resources globally. The industrial and urban symbiosis are patterns implementing Circular Economy that is to maximise the recycling and reuse of resources within a collaborative environment. However, the circularity rate of the system cannot reach 100 %. This is not a sufficient criterion for designing and operating symbiosis in an optimal way. The current work shows that it is crucial to consider the cost, resource, exergy and footprint implications explicitly, in a combined way, for finding the optimal circularity rate. The proposed model is applied to evaluate the trends of the total cost, exergy footprint, water and Greenhouse gas footprints. The case study on the treatment of Municipal Solid Waste is used as a demonstration for evaluating the trade-offs between the cost, Exergy Footprint and environmental footprints against the circularity rate. The results show an approximate 10 %...
The global plastic consumption is consistently increasing, and plastic recycling is still a cruci... more The global plastic consumption is consistently increasing, and plastic recycling is still a crucial issue to be solved due to the depletion of fossil resources. The polymers in the plastic can be chemically enhanced with materials such as colourants or metal fillers. This work aims to analyse the metal contamination data in the virgin plastic and plastic waste to derive a general categorisation rule for different plastic polymers (PET, PE, PP, PS). The metals contamination in plastics can be accumulated during use or waste management practices during recycling, which can be harmful for application. The metal concentrations for plastic streams are sampled from different origins: virgin plastic, household waste, and reprocessed household and industrial waste. Machine Learning methods, specifically the tree-based classification models, are used to derive a series of ‘if-then’ rules for classifying the plastic waste based on the sampled data. This helps the identification of the data pa...
Heat exchanger network (HEN) synthesis is an efficient way for Heat Integration in the process in... more Heat exchanger network (HEN) synthesis is an efficient way for Heat Integration in the process industry. The non-linear nature of the problem leads the solution to easily be trapped into local optima. This work proposes a mixed-linear programming model (MILP)-based iteration method for HEN synthesis. The MILP aims to minimise the total annualised cost, including utility and investment cost. The logarithmic mean temperature difference (LMTD), heat transfer area, and the investment cost are linearised. The coefficients of the linearised equations are obtained by data regression. And they are evolved through the designed iteration algorithm. Two cases have been tested to show the effectiveness of the proposed method. Results show that the proposed method is accurate on the calculation of total annualised cost, the errors for Case 1 and 2 are 0% and 0.082% compared to the results calculated by the original equations. This provides a way to solve the HEN synthesis problem in a reasonable...
Careful assets maintenance planning is crucial in ensuring minimal process interruptions in a che... more Careful assets maintenance planning is crucial in ensuring minimal process interruptions in a chemical plant while fulfilling production demand. This paper aims to propose a systematic framework with easily comprehensible tools for effective and efficient maintenance optimisation. The first step is to identify the optimal maintenance time for the equipment depending on their failure time distributions, minimising the expected maintenance cost. A maintenance tasks clustering model is then formulated for grouping individual preventive maintenance actions, to save the production downtime and cost. The solutions from long-term planning are transferred to the short-term planning model for detailed manpower scheduling. In this work, Pinch Analysis is selected as the targeting tool to maximise the available manpower utilisation and target the extra working hours needed. The daily maintenance tasks are formulated as the ‘Demand/Sink’, while the workers’ shifts are the ‘Supply/Source’. This ...
This work discusses a crucial activity for Heat Integration (HI): Data Extraction (DE). Overall, ... more This work discusses a crucial activity for Heat Integration (HI): Data Extraction (DE). Overall, data acquisition is a complex process involving many stages and stakeholders. The paper analyses the treatment of DE in the published literature. The analysis established that many publications just present the results from already performed DE and others limit the provided reasoning only to a few key issues. Further, the importance of the preservation of data integrity and semantics is highlighted. This can be done by documenting the reasoning and the choices made during DE, as well as distributing the DE reasoning between the general discussion and stream-specific information placement into the Process Streams Table for HI, preserving the context. The approach is illustrated on a published example.
The opportunistic maintenance (OM) approach allows exploiting the stoppage for performing additio... more The opportunistic maintenance (OM) approach allows exploiting the stoppage for performing additional maintenance actions alongside those planned, to save cost and time. This study aims to propose a graphical approach to identify the optimal maintenance grouping strategies in an operating process. The failure of a specific component is predicted by using the statistically-derived probability distribution function that reflects its time-variant failure behaviours. The periodic maintenance schedule is first derived, and the system failure likelihood is predicted within each time interval. The failure of one of the component creates an opportunity to reschedule maintenance activities, which can be carried out while replacing the failed components. The expected cost to mitigate the failures (‘Sinks’) can be reduced by the expected maintenance reschedule cost savings (‘Sources’) based on the derived schedule previously. In this work, Pinch Analysis is used as a targeting tool to determine...
31st European Symposium on Computer Aided Process Engineering, 2021
The decisions on synthesising a process network are often to optimise the payback periods based o... more The decisions on synthesising a process network are often to optimise the payback periods based on investment cost. In addition to the core investment and the cost of used resources, the long-term reliable operation of the process is also crucial. Given available states and technologies of the assets, this study aims to identify the long-term optimal asset planning policy. Markov Decision Process (MDP) is a promising tool in identifying the optimal policy under different states of the assets or equipment. The failure probability of the unit is modelled with the ‘bathtub’ model and each of the condition states are incorporated in the MDP. The decisions to implement the redundant units in the process with variety of technologies are allowed. This paper applied the MDP into an equivalent Mixed Integer Non-linear Programming (MINLP) to solve for the optimal long-term assets decision and the maintenance policy. The applicability of the method is tested on a real case study from Sinopec P...
Sophisticated approaches have been proposed to reduce material utilities such as water and hydrog... more Sophisticated approaches have been proposed to reduce material utilities such as water and hydrogen by designing resource allocation networks. For resource targeting, graphical methods have been developed for single quality material recycle/reuse. Up to now, systematic approaches to targeting fresh resources in a multi-contaminant material recycling network ahead of the detailed design are not readily available. This work presents a rigorous resource targeting procedure in the domain of multiple constraints (e.g. multi-contaminants). The problem is formulated as a resource-allocation superstructure model and modified to determine the model characteristics and obtain the optimal solution. These conditions are then transformed into a table and graphical forms to identify the minimum resource target. By inferring from the mathematical formulations, multiple cascades with individual contaminant/quality have to be analysed sequentially. The main issues are the identification of the prope...
This article evaluates the processing of Municipal Solid Waste (MSW) and its contribution to sust... more This article evaluates the processing of Municipal Solid Waste (MSW) and its contribution to sustainability from the viewpoint of its net exergy balance. The evaluation follows the recent framework for estimation of Exergy Footprint and Exergy Profit for a given Process System. The method evaluates the Exergy Assets and Liabilities, estimating the Exergy Profit as the balance of these two. The concept of avoided exergy by substituting the useful chemical to its primary production, similar to the concept of avoided emission is also proposed in this work. The obtained estimate is the specific contribution of the considered MSW processing system. For estimating the overall impacts, the obtained Exergy Profit has to be added to the contributions of the potential upstream and downstream processes. The results show the potential value that can be obtained and sustainability contribution to be achieved by the extraction of useful chemicals from waste and waste-to-energy conversion. The che...
This work addresses the internal and Total Site Water Network design with water mains. A Material... more This work addresses the internal and Total Site Water Network design with water mains. A Material Recovery Pinch Diagram is used for freshwater targeting and a Water Integration Network design with...
The Circular Economy principle has to be applied more vigorously to tackle the rapid depletion of... more The Circular Economy principle has to be applied more vigorously to tackle the rapid depletion of resources globally. The industrial and urban symbiosis are patterns implementing Circular Economy that is to maximise the recycling and reuse of resources within a collaborative environment. However, the circularity rate of the system cannot reach 100 %. This is not a sufficient criterion for designing and operating symbiosis in an optimal way. The current work shows that it is crucial to consider the cost, resource, exergy and footprint implications explicitly, in a combined way, for finding the optimal circularity rate. The proposed model is applied to evaluate the trends of the total cost, exergy footprint, water and Greenhouse gas footprints. The case study on the treatment of Municipal Solid Waste is used as a demonstration for evaluating the trade-offs between the cost, Exergy Footprint and environmental footprints against the circularity rate. The results show an approximate 10 %...
The global plastic consumption is consistently increasing, and plastic recycling is still a cruci... more The global plastic consumption is consistently increasing, and plastic recycling is still a crucial issue to be solved due to the depletion of fossil resources. The polymers in the plastic can be chemically enhanced with materials such as colourants or metal fillers. This work aims to analyse the metal contamination data in the virgin plastic and plastic waste to derive a general categorisation rule for different plastic polymers (PET, PE, PP, PS). The metals contamination in plastics can be accumulated during use or waste management practices during recycling, which can be harmful for application. The metal concentrations for plastic streams are sampled from different origins: virgin plastic, household waste, and reprocessed household and industrial waste. Machine Learning methods, specifically the tree-based classification models, are used to derive a series of ‘if-then’ rules for classifying the plastic waste based on the sampled data. This helps the identification of the data pa...
Heat exchanger network (HEN) synthesis is an efficient way for Heat Integration in the process in... more Heat exchanger network (HEN) synthesis is an efficient way for Heat Integration in the process industry. The non-linear nature of the problem leads the solution to easily be trapped into local optima. This work proposes a mixed-linear programming model (MILP)-based iteration method for HEN synthesis. The MILP aims to minimise the total annualised cost, including utility and investment cost. The logarithmic mean temperature difference (LMTD), heat transfer area, and the investment cost are linearised. The coefficients of the linearised equations are obtained by data regression. And they are evolved through the designed iteration algorithm. Two cases have been tested to show the effectiveness of the proposed method. Results show that the proposed method is accurate on the calculation of total annualised cost, the errors for Case 1 and 2 are 0% and 0.082% compared to the results calculated by the original equations. This provides a way to solve the HEN synthesis problem in a reasonable...
Careful assets maintenance planning is crucial in ensuring minimal process interruptions in a che... more Careful assets maintenance planning is crucial in ensuring minimal process interruptions in a chemical plant while fulfilling production demand. This paper aims to propose a systematic framework with easily comprehensible tools for effective and efficient maintenance optimisation. The first step is to identify the optimal maintenance time for the equipment depending on their failure time distributions, minimising the expected maintenance cost. A maintenance tasks clustering model is then formulated for grouping individual preventive maintenance actions, to save the production downtime and cost. The solutions from long-term planning are transferred to the short-term planning model for detailed manpower scheduling. In this work, Pinch Analysis is selected as the targeting tool to maximise the available manpower utilisation and target the extra working hours needed. The daily maintenance tasks are formulated as the ‘Demand/Sink’, while the workers’ shifts are the ‘Supply/Source’. This ...
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Papers by Hon Huin Chin