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In refineries, some hydrogen-rich streams contain considerable light hydrocarbons that are important raw materials for the chemical industry. Integrating hydrogen networks with light hydrocarbon recovery can enhance the reuse of both hydrogen and light hydrocarbons. This work proposes an automated method for targeting hydrogen networks with light hydrocarbon recovery. A pinch-based algebraic method is improved to determine the minimum fresh hydrogen consumption and hydrogen sources fed into the light hydrocarbon recovery unit automatically. Rigorous process simulation is conducted to determine the mass and energy balances of the light hydrocarbon recovery process. The targeting procedures are developed through combination of the improved pinch method and rigorous process simulation. This hybrid method is realized by coupling the Matlab and Aspen HYSYS platforms. A refinery hydrogen network is analyzed to illustrate application of the proposed method. The integration of hydrogen networks with light hydrocarbon recovery further reduces fresh hydrogen requirement by 463.0 Nm3·h-1 and recovers liquefied petroleum gas and gasoline of 1711.5 kg·h-1 and 643 kg·h-1, respectively. A payback period of 9.2 months indicates that investment in light hydrocarbon recovery is economically attractive.

In this paper, heat integration was coupled with serpentine preheating temperature optimization and was for the first time applied to a mineral carbonation process. For this, a process was selected with the aim to minimise its heat demand. Aspen® Energy Analyzer software was used for heat integration with pinch analysis. The mineral carbonation plant considered here processes 100 tonnes of serpentine per hour, with Mg content of 237 kg per tonne of rock, corresponding to 0.88 million tonnes per year to treat 0.5 million tonnes of CO2 emitted from a cement plant. In the base case considered for heat integration, 50% of the serpentine magnesium content was converted to hydromagnesite using 30% of the flue gas CO2 which means that 5.85 tonnes of rocks were required to capture 1 tonne of CO2. The serpentine preheating temperature, was optimized as 400 °C. Application of heat integration at this solid preheat temperature reduced the process heat demand by 25% compared to our previous study, as 5.0 GJ per tonne of CO2 captured or 9.5 GJ per tonne of CO2 avoided. This corresponds to 0.86 GJ per tonne of ore as the process heat demand was only attributed to the mineral activation. In addition, the impact of process parameters including the solid-liquid ratio and the dissolution reaction extent on the heat integration strategy was evaluated. It was found that solids concentrations as low as 5% substantially reduced the sequestration efficiency as the process waste heat was not sufficient at the optimized solid preheat temperature. Furthermore, the uncertainty behind unknown parameters such as activated serpentine heat capacity and solid heat transfer coefficient was evaluated to validate the study.

Objective: The current study aims mainly to Maximize Condensate Recovery (NGLs), focusing on a gas processing train of Gas-Oil Separation Plant (GOSP) located in Egypt with a capacity of 4,230 kmole/h. Methods: The research study accounts for the constraint of Reid Vapor Pressure (RVP) specification, which makes the storage in floating roof tanks is of a great risk. The study proposes the installation of the cryogenic train that recovers condensates (C4+). This train comprises of compression unit, expansion unit, three-phase separators and a re-boiled absorber. The problem of RVP will no longer exist because of the re-boiled absorber achieving RVP according to export specifications (RVP below 82.74 kPa). Heat integration is applied over the whole process to minimize the reliability of the external utilities. Further, an Organic Rankine cycle (ORC) is introduced to the existing unit for more heat integration to develop useful work from process waste heat. Furthermore, both environmental emissions of CO2 and economic implications are investigated. Results: Energy integration played a vital role in decreasing the compressing power by about 31%, the cooling load by about 81%, and eliminating the heating load leading to zero CO2 emissions. Conclusion: The new energy-integrated retrofit scenarios exceed the recommended revamping schemes by previous works and base case in all aspects of condensate recovery, energy-saving, environmental concerning and economics.

This paper aims to develop an innovative and practical method to accelerate Pinch Analysis problems using a combination of process integration, process simulation tools, and life cycle assessment techniques to design effective industrial energy efficiency measures rapidly. Data extraction and analysis is accelerated using the workflow, reducing pinch analysis duration, and therefore cost. This lowers financial barriers and is expected to help facilitate an increase in the number of conducted pinch analyses each year. An innovative ecological targeting step has been included in the workflow, which represents the option for end-users to further their CO2 savings, once energy targeting has been completed on a purely cost basis. It is expected that optimizing for costs first will enable the implementation of heat recovery solutions in industry. The methodology is applied to an example case study, and the learnings from industrial application is reported.

Pinch analysis is a methodology for minimizing energy and mass consumption in different industries. It has been widely applied for more efficient processes. This study presents a new graphical-approach to analyze and design Mass Integration (MI) and exchange networks that follows Pinch principles to guarantee maximum mass recovery with minimum losses. This technique uses the composition driving forces in network representation as it rules the mass transfer between streams. The proposed approach can be applied on both existing mass networks as well as new ones. This graphical representation a visual descriptive design tool to describe and explain the details of operations with minimum calculations. Besides, it is found to be valuable for conceptual applications on linear dilute systems. The performance of mass-exchange networks is evaluated and suggested improvements can be recommended in terms of composition driving forces inside mass exchangers. In this approach, the x-axis represents the equivalent lean stream compositions, whilst the y-axis represents the difference in compositions for each stream in the exchanger. Pinch Analysis principles are embedded within the graphical representation. A scrap-tires-to-fuel plant case study was considered for the application of the new approach. The plant was designed with Mass Integration targets in consideration. Optimum matches were selected based on maximum driving force, minimum flow and minimum cost. In general, this approach can help synthesize mass networks, whilst maintaining maximum driving force - and thus minimum equipment size and minimum flow.

The Digital Twin concept undoubtedly emerges in different industries as a must-have option for improving energy efficiency, increase maintenance reliability, prevent environmental pollution, and mi...

The design of distillation columns often considers a given fixed feedstock and nominal operating conditions. Here we present an optimization-based approach for the optimal design of these units considering a flexible operation under a range of potential feedstocks. Our method combines an artificial neural network with a support vector machine to model the crude oil distillation unit. The artificial neural network model predicts the performance of the distillation unit for a given crude oil feedstock whilst the support vector machine classifier filters out infeasible design alternatives from the solution space (i.e., designs that are unlikely to converge when simulated using a rigorous model). The inputs to the artificial neural network include the column structural variables and operating conditions, whilst the outputs are process variables linked to the column performance. The artificial neural network models and support vector machines constructed for different crude oil feedstocks are integrated into a two-stage optimization framework in order to optimize the column structural variables and operating conditions, where the minimum utility demand is estimated using the pinch analysis. An effective solution strategy that combines stochastic and deterministic optimization algorithms is applied to search for economically viable and flexible design alternatives that can operate over a given range of crude oil feedstocks while satisfying the product quality specifications. The capabilities of the proposed approach are illustrated using an industrially-relevant case study, where we clearly show that the proposed approach can identify design alternatives capable of handling various feedstocks effectively.

Fire disasters pose a severe threat to the functionality of the cities and their sustainable development. Lack of analytical approach in research literature hinders the development of a fire-resilient city. A novel analytical framework is proposed in this paper to reduce the overall fire susceptibility of a city through a cost-effective redevelopment of the existing urban built forms (UBF). The proposed framework involves a regression model to capture the linear relationship between the fire susceptibility of an area and the built-up variables at a granular scale. Additionally, extended pinch analysis is incorporated in the framework to minimize the financial expenses incurred during the redevelopment, for the reduction in fire susceptibility of a city. The applicability of the proposed framework is demonstrated through a case study involving the southern region of Mumbai, India. The results suggest medium-rise buildings should be the main constituent for the UBF in Mumbai to reduce its fire susceptibility cost-effectively. Based on the illustrated case study, specific policies are recommended. The proposed novel methodology endorses a holistic decision-making process, applicable in developing fire-resilient cities in developing countries.

Pinch Analysis helps in achieving sustainable development through conserving resources in various source-sink resource conservation networks. Diverse applications and methodologies of Pinch Analysi...

Retrofit of the refinery hydrogen network is one of the important issues faced by modern refineries. Refinery off-gas streams are rich in hydrogen and valuable light hydrocarbons. Light hydrocarbons recovery (LHR) process can recover the valuable hydrocarbons and generate the hydrogen-rich stream for reuse and recycle. We firstly propose the systematic procedure for the retrofit of refinery hydrogen network integrated with LHR process. The approach combines the pinch analysis technique and process modelling and simulation. The typical pinch analysis technique (i.e. problem table) is used to determine the flowrate targets. Aspen HYSYS is used for the modelling and simulation of LHR process. The retrofit of an industrial refinery hydrogen network is conducted to illustrate the procedure. Results show that the benefit of retrofit scheme (Integrated Scheme 3) with LHR reaches 7.488 million CNY/y, and the investment payback period is only 8 months.

Pinch analysis was applied to optimize the heat exchange network used in the moisture removal processes of energy plants. The moisture removal process absorbs moisture from natural gas using glycol as an absorbent, and the recycling process then separates moisture from the H2O-rich glycol in a regenerator column by applying the principle of vapor-liquid equilibria. For the dehydration process of a natural gas plant, the heat and mass flows are properly established and calculated by means of a static process model for a utility system embedded in the process based on the properties of natural gas. The results of the calculation generate a T-H composite curve that can be used to compare the pinch and to assess the installation and operating costs for the target temperature. The results show that approximately 61% of the total heat supply can be replaced with low-pressure steam, depending on the optimization of the heat exchanger network of the moisture removal process. Further, the annual operating costs can be reduced by about 17% in this case.

Process energy data is integral to the sustainability analysis of chemical products and processes. However, due to the lack of primary data from chemical plants, process energy calculations in chem...

Polymer electrolyte fuel cells are considered as a promising alternative to mitigate the CO2 emission in the transport sector. To achieve an efficient and cost-effective system, hybridisation of the energy storage system with a fuel cell is important. Efficient management of energy is the key in order to achieve an efficient and cost-effective configuration for fuel cell electric vehicle. Optimum sizing of the power source and energy storage system, which is capable of meeting the load requirement of the driving cycle is the key challenge for achieving efficient and cost-effective system. In this work, an alternative methodology based on the principles of pinch analysis is proposed, for sizing the energy storage system and the fuel cell for fuel cell-based electric vehicle, and validated for the Worldwide Harmonized Light Vehicle Test Cycle (WLTC) class-3 driving cycle.

Carbon dioxide (CO2) emission will increase due to the increasing global plastic demand. Statistical data shows that plastic production alone will contribute to at least 20% of the annual global carbon budget in the near future. Hence, several alternative methods are recommended to overcome this problem, such as bio-product synthesis. Algae consist of diverse species and have huge potential to be a promising biomass feedstock for a range of purposes, including bio-oil production. The convenient cultivation method of algae could be one of the main support for algal biomass utilization. The aim of this study is to forecast and outline the strategies in order to meet the future demand (year 2050) of plastic production and, at the same time, reduce CO2 emission by replacing the conventional plastic with bio-based plastic. In this paper, the analysis for 25%, 50% and 75% CO2 reduction has been done by using carbon emission pinch analysis. The strategies of biomass utilization in Malaysia are also enumerated in this study. This study suggested that the algal biomass found in Malaysia coastal areas should be utilized and cultivated on a larger scale in order to meet the increasing plastic demand and, at the same time, reduce carbon footprint. Some of the potential areas for macroalgae sea-farming cultivation in Sabah coastline (Malaysia), comprised of about 3885 km2 (388,500 ha) in total, have been highlighted. These potential areas have the potential to produce up to 14.5 million tonnes (Mt)/y of macroalgae in total, which can contribute 370 Mt of phenol for bioplastic production., Graphical Abstract

The objective of this paper is to perform an energy optimization study using pinch analysis on the Heat Exchanger Network (HEN) of a Crude Distillation Unit to maximum heat recovery, minimize energy consumption and increase refining margin. The heat exchanger network (HEN) considered comprises exchangers from the pre-heat section of the atmospheric distillation unit, which recovers heat from the product streams to incrementally heat the crude oil feed stream before entering the furnace. This paper illustrates how to perform a detailed HEN retrofitting study using an established design method known as Pinch Analysis to reduce the operating cost by increasing energy savings of the HEN of an existing complex refinery of moderate capacity. Analysis and optimization were carried out on the HEN of the CDU consist a total of 19 heat exchangers which include: process to process (P2P) heat exchangers, heaters and coolers. In the analysis, different feasible retrofit scenarios were generated using the pinch analysis approach. The retrofit designs included the addition of new heat exchangers, rearrangement of heat exchanger (re-sequencing) and re-piping of existing exchangers. Aspen Hysys V9 was used to simulate the CDU and Aspen Energy Analyser was used to perform pinch analysis on the HEN of the pre-heat train. Several retrofit scenarios were generated, the optimum retrofit solution was a trade-off between the capital cost of increasing heat exchanger surface area, payback time, energy / operating cost savings of hot and cold utilities. Results indicated that by rearrangement (Re-sequencing), the pre-heat train can reduce hot (fired heat) and cold (air and cooling water) utilities consumption to improve energy savings by 8% which includes savings on fired heat of about 4.6 MW for a payback period of 2 years on capital investment. The results generated were based on a ΔTmin of 10°C and pinch temperature of 46.3°C. Initial sensitivity analysis on the ΔTmin indicated that variation of total cost index is quite sensitive and increases with increase in ΔTmin at the temperature range of 14.5-30°C, however total cost index remains constant and minimal at a temperature range between 10°C-14.5°C for the CDU preheat train under study. In addition, the implementation of the optimum retrofit result is straightforward and feasible with minimum changes to the existing base case/design.

Energy integration of the existing chemical and petrochemical facilities is regarded as a keystone for sustainable energy systems. It is widely known that a considerable number of the petrochemical industries are not applying efficient heat exchanger network (HEN) systems to minimise the use of external utilities. In the present study, a Pinch Analysis-based graphical approach is used to retrofit an existing HEN for optimising a crude oil distillation operation. The existing HEN is represented using Thot–Tcold diagram, where the cold stream temperatures are plotted on the x-axis and the hot stream temperatures are plotted on the y-axis, for each exchanger unit. The graphical approach is applied to a real case study of a petroleum refinery plant located in Kuwait with the objective of performing energy analysis and retrofitting the existing HEN. Retrofit modifications are extracted from the graphical representation to enable scenarios for energy and emission reduction. The application of the proposed approach resulted in substantial energy savings of about 10.4 MW compared to the current operation, leading to annual operating cost savings of about MM$2 and less than one-year payback time. Overall, this study provides tools to address the energy traits in crude preheat trains of industrial feature, which can improve the overall economic–environmental sustainability of existing refineries.

With the increasing demand for transportation and alarming levels of emissions witnessed today, the future of the transport sector is at a critical juncture. The challenge lies in satisfying the demand of increasing population and simultaneously reducing the emission level for sustainable future development. This study dealt with the problem of increasing demand and desired a reduction in emission level for the transport sector by finding an optimal modal split for passenger transportation, putting a constraint on emissions and minimizing the cost of investment. We applied the techniques of pinch analysis to derive the optimum mix. Various scenarios were developed having different emission levels as constraints, and results were compared based on the contribution of different modes of transport that might aid the policymakers to introduce policies to achieve emission reduction targets. It is evident from the estimated models that substantial reduction is possible with the introduction of newer technologies, adept transportation planning strategies.

This article will help to consider the problem of thermodynamic optimization of heat power equipment. Solving this issue will allow to increase the energy efficiency of thermal systems by reducing the cost of energy resources. There is a large number of methods for studying power plants, and we will combine two of them: the exergy method and the pinch method. Exergy analysis of thermal systems shows quantitative and qualitative characteristics of efficiency. The pinch method allows us to solve specific design problems to optimize the parameters of heat power facilities. The pinch analysis is based on enthalpy, which does not take into account the heat potential. We propose to conduct a pinch analysis of thermal energy sources using exergy, which can better assess the potential of heat fluxes and show the dependence of the energy of heat fluxes on the ambient temperature. The article provides an exergy analysis of a direct-flow boiler PP2650-255 GM using the pinch method. The results of our work show that in order to increase the energy efficiency of the boiler, it is possible to change the area of the heating surfaces of the economizer and air heater. Thus, exergy pinch analysis is an effective method for increasing the energy efficiency of heat power equipment.

Straw pulp in China, which is the world's largest producer of this material, suffers from water and energy shortages during its entire life cycle. However, limited systematic studies have focused on these issues, and decision makers need be provided with improvement methods for the environmental performance. Thus, an impact-oriented energy and carbon coupled water footprint analysis was conducted in this study based on ISO standards. Results showed that the impact of energy consumption and carbon emissions exceeded that of water footprint. Carcinogens, non-carcinogens, and freshwater ecotoxicity also played effective roles in improving the environmental performance. Optimizing key indirect processes, including chemicals production, steam preparation, electricity generation, wood pulping, and fertilizer recovery, dominated the reduction in environmental burdens. Direct freshwater consumption and wastewater disposal played additional effective roles in controlling water footprint. The water network was thus optimized by a water pinch analysis to decrease the freshwater consumption and pollutant emissions by maximum values of 91.5% and 99.7% after optimization, respectively. Meanwhile, carbon dioxide, methane, chromium, arsenic, mercury, titanium, copper, strontium, total nitrogen, total phosphorus, BOD5, and COD were the main pollutants. Overall, the environmental impact can be further reduced by diminishing coal power ratio in national energy structure, adopting recovered steam, and considering multistage regeneration water network to cope with different water use demands.

The improvement of thermal energy use in batch and semi-continuous processes utilizing established techniques such as Pinch Analysis faces challenges as direct heat recovery is restricted and schedule dependent, limiting broad industrial application. In overcoming this limitation, sensible heat storage integration has proven to be effective in achieving significant and less schedule-sensitive heat recovery but designing solutions is problematic given the complex trade-offs that occur. The presented graphical design method relies on the Indirect Sources Sinks Profiles (ISSPs) which extends the scope of time-average models and brings a systematic foundation to the design procedure. Graphical assignment zones are introduced to represent on the ISSPs constraints and degrees of freedom that apply when designing the Heat Exchanger and Storage Network (HESN) that can achieve the target heat recovery, given by ISSP overlap. A general procedure for their determination is presented, alongside resulting HESN designs for a case study process which achieve utility reductions of 35.0% up to 76.0%. Designs are automatically balanced making them functional concepts without manual adjustment, and although not cost-optimized, are inherently reduced in complexity by the method and suitable for further stepwise improvement.

Heat-integrated water network (HIWN) is an active area of research in the past decade. It focuses on simultaneous saving of energy and water, which are both important resources to enhance sustainability for the process plants. This problem has been previously approached using insight-based pinch analysis and mathematical programming techniques. In this work, an alternative optimization tool, process graph (P-graph) framework is utilized to solve for water and energy integration. P-graph is a graph-theoretic approach to process synthesis, for which the developed algorithms can reduce the complexity of the mathematical programming algorithms efficiently. P-graph methodology enables the effective generation of sub-optimal network structures that allow wider exploration of alternatives through network topology. This paper also introduces some transformation techniques to convert the non-linear programming (NLP) model in the non-isothermal HIWN problem into model which is solvable using P-graph. Two examples with different water recovery schemes are used to elucidate the proposed approach, covering both direct recycle/reuse and regeneration networks; for both cases, isothermal and non-isothermal mixing problems are solved.

Water scarcity has led process industries to seek measures, such as in-plant and interplant recovery, for its efficient utilization. While considering interplant integration, mere water conservation can incur substantial investment cost due to a large number and distance of pipelines required as well as pumping costs associated with interplant flows. The interplant flow, and hence the costs associated with it, can be reduced by adding some amount of fresh water. The primary objective of this study is to explore the trade-offs between fresh water consumption and the interplant flow. A novel method, based on the extensions of Pinch analysis, is developed to accurately capture the trade-offs through Pareto optimal solutions. The graphical and algebraic nature of the developed technique provides efficient solutions with enhanced visualization. The method is illustrated through examples of water and hydrogen allocation networks.

Pinch Analysis (PA) and Exergy Analysis have been used, either independently or in combination, for energy integration of process plants. This paper discusses a methodology to apply PA and Exergy Analysis during design of a new process plant to make it energy efficient, using Diesel Hydrotreating Unit (DHT) as an example. PA has been used to estimate the Minimum Energy Requirement (MER), to select utilities and to design the optimal Heat Exchanger Network (HEN). Exergy Analysis is then performed to pinpoint the sources of energy inefficiency in the whole plant and suggest improvements. The application of these two techniques has helped in energy integration of the plant during the design phase itself. Two common layouts of diesel hydrotreating unit—the ‘hot separator layout’ and the ‘cold separator layout’—have been studied. The minimum Total Annualized Cost (TAC) is ∼7.6 M€/y and ∼10 M€/y for the hot separator layout and the cold separator layout respectively. Exergy destroyed is 27.15 MW (7.9% of exergy input) and 50.18 MW (6.7% of exergy input) respectively for the hot separator layout and the cold separator layout. Exergy Analysis reveals that the energy efficiency can be improved for air coolers, fired heaters and letdown valves.

This paper focuses on industrial heat pump (HP) integration in non-continuous processes. To achieve the necessary time-wise process decoupling of the HP system, heat recovery loops (HRLs) with stratified storages are used. This design type can be modeled as a mixed integer nonlinear programming problem which often results in expensive mathematical formulations. The challenge is addressed by a practical method that combines the insight based approach of Pinch Analysis with mathematical programming techniques to give the engineer more flexibility for the application of the method and to avoid long computation times. By the use of the insight based methods, the solution space of the mathematical formulation is restricted, and thus its complexity is reduced to a nonlinear programming problem optimizing the temperature levels in the HP-HRL system. As an objective, total annual costs (TAC) of the HP-HRL system are minimized. The developed hybrid method is applied to a dairy site and compared in terms of approach temperatures, temperature lift of the HP, TAC, and greenhouse gas emissions to the existing methods. It is shown, that the hybrid method provides realistic approach temperatures in contrast to the existing insight based method.

This study proposes the use of a waste management procedure based on the technical development and practical implementation of a “Multi-Waste Plant” concept. A final point of this model is to reduce the costs related to waste treatment processes, thus optimizing its management, from the ecological viewpoint, as well as from the money related perspective. To this end, it is proposed: 1. Treatment, in the same facility, of various types of waste: municipal, industrial, biomass; 2. Energy and mass integration of individual waste treatment processes (anaerobic digestion and pyrolysis) to obtain a single integrated process more economical; 3. Complete recuperation of waste as energy (biogas, syngas and carbon pellets) and slow-release fertilizers (struvite). As a result, stable codigestion of a mix of poultry manure, pig manure, and vegetable waste (40/40/20 w/w) was achieved in a two-phase biodigester with production of biogas (65%CH4, energy content 6.5kWhm−3) and non-harmful digestate with phytotoxicity less than 25 Equitoxm−3, later transformed in struvite fertilizer with up to 95,4% of nutrients recovery. In parallel, the pyrolysis of a mix of organic fraction, waste biomass, plastic waste and other industrial waste (15/15/50/20 w/w) at 420-450°C produced non-condensable gas (86.2%, LHV 8.5kWhm−3), char (9%) and a liquid phase (4.8%). A Pinch analysis reveals that an energy integration process in the plant will make possible to cover energy needs of the whole facility. The “Multi-Waste Plant” concept along these lines turns into an unmistakable example of the circular economy model.

There is an increasing research interest in the recovery of cooling capacity stored in cryogenic liquids (CLs) for industrial applications, especially for LNG regasification systems. In this study, a novel heat exchanger network (HEN) has been designed for cryogenic liquid regasification process to recover the released cooling capacity and develop a frozen-free heat transfer system with compact structure and high efficiency. Firstly, the specific design concept is proposed to employ the gasified CL as multiple cyclic streams to vaporize its own liquid in the evaporator, which allows a large temperature difference and a compact structure for the vaporization of the CL. Then, according to the optimization design of the flow arrangement, heat exchanger structure and flow rate control, the temperature of the heat medium can always be kept above its freezing point in the superheater and recuperator. Finally, the heat medium as the coolant extracts and transports the cryogenic cooling capacity from the CL to other refrigerated spaces, which can achieve various discharge temperatures to meet the requirements of different kinds of applications by adjusting the circulation number of the cyclic streams and the flow rates of the fluids. In the process calculation, the specific design parameters and energy balance relation of the HEN are obtained, and the cooling capacity recovery efficiency of the HEN system is analyzed using the pinch technique. A prototype of the heat exchanger network is designed and corresponding experiments are carried out for the regasification process of liquid nitrogen. The results indicate that the recovered cooling capacity and recovery efficiency of the prototype can, respectively, reach up to 17.5 kW and 90% within a 7.5% error range, which proves the feasibility of the novel HEN proposed in this paper.

Energy integration relies on matching process hot streams with process cold streams, and utilities are only introduced to balance the deficit in energy consumption. A systematic but simple Pinch Analysis (PA)-based retrofit approach is proposed to lessen the utility consumption of any industrial heat exchanger network (HEN) under new minimum temperature approach (ΔTms) at the cost of minor capital investment. This work is an extended and improved version of our previous work ( Li and Chang, 2010 ). Elaborate visualized tool of T–H diagram for identification of cross-pinch heat load is proposed to fully address the case that phases change in the cross-pinch heat exchanger. Main characters of industrial HENs which are large scale, varied heat capacity flow rate and multiple pinches are fully addressed. Specifically, each cross-pinch exchanger or match is identified and those matches with large cross-pinch loads are disconnected first, and then their heat loads on the hot and cold stream side are split according to pinch temperatures. Next, at either side of or between the pinches, the divided heat loads on each stream are combined and matched according to a systematic Pinch Analysis (PA) based procedure. Retrofit modifications are focused on those cross-pinch matches and utility exchangers, so the retrofit procedure of an industrial HEN is obviously simplified. An industrial case of Crude oil preheat train (COPT) is retrofitted to demonstrate the effectiveness of the proposed approach.

Seawater desalination is useful for supplementing the freshwater supply to coastal industrial parks. However, high cost and energy consumption is a serious disadvantage of typical desalination plants. Subsidy from government can incentivize investments to increase supply of desalinated water. However, the subsidy must be calibrated to minimize cost to the public. A graphical pinch analysis method is developed to determine the optimal subsidy for water desalination, taking into account local water price as well as supply and demand. This method uses the Limiting Composite Curve (LCC) as basis for the optimal subsidy; the minimum quantity of desalinated water is also determined. Next, the minimum subsidy is determined by relaxing the subsidized price of desalinated water. The proposed method is demonstrated through an illustrative industrial park case study. Results show that the optimal subsidy for desalinated water is $0.35/t. Sensitivity analysis shows that, when subsidy increases, demand for desalinated water increases and displaces the demand for other water resources. Furthermore, analysis of the Water-Energy Nexus is conducted to find the minimum energy consumption per unit of water at the optimal subsidy level. The proposed method can provide options for the industrial park to achieve the economic development, while minimizing the environmental impact of water supply mix.

The results of a pinch analysis of the efficiency of heat-exchange system of ethylbenzene dehydrogenation process are presented. The energy characteristics and target values of energy consumption were obtained and the utilization degree of the energy potentials of the heat-exchange system internal flows was evaluated. A potential for increasing the efficiency of thermal energy usage was estimated. Recommendations for improving the technology of the ethylbenzene dehydrogenation process were formulated based on the results, allowing an increase in the flexibility of the process, as well as the degree of its energy integration by 25%.

The emphasis of this paper is to show the existence of some non-energy benefits that can be taken into account in an energy efficiency investment aimed to reduce energy consumption and increase production and product quality in an oil and gas processing center (OGPC) in Mexico. The function of OGPC is to separate crude oil, gas, and saltwater coming from marine and terrestrial oil fields. Traditionally, application of process energy integration techniques has been aimed to reduce energy consumption associated with heating and cooling services. In this paper, the process energy integration (standard pinch analysis) of an OGPC shows the possibility of reducing natural gas and electricity consumption by 75 % and 98 %, respectively. However, the novel aspect of this work is the identifications and use of some waste heat streams available in processes to reduce energy consumption, and more importantly couple them with some non-energy-related benefits to produce massive economical savings. For example, by allowing an improvement in the quality of heavy crude oil for exportation (reduction in salt content), an increased sale price of 0.6 USD/barrel is achieved, rising profit to 156.88 MMUSD/year. Additional economic benefits came from the restauration of the production of 3,711 barrel of naphtha per day (33.86 MMUSD/year), by solving security issues related to the use of direct-fire heaters in the condensate stabilization plant.

Global warming is a major international issue due to rising levels of greenhouse gases such as CO2. Many countries now face the challenge to find cost-effective ways to deploy low-carbon technologies in order to meet commitments to the Paris Agreement. Process systems engineering (PSE) can play an essential role in supporting high-level policy decisions to help mitigate climate change. Within PSE, carbon-constrained planning will become increasingly critical for policy-making on provision of sustainable energy in electricity generation as well as other economic sectors. There are existing carbon-constrained planning tools but these often consider energy issues from limited perspectives at specific scales. In this perspective paper, we argue for a Process-to-Policy framework that centres on carbon-constrained planning which includes various stakeholders at various scales for developing strategies to address global warming. There is an urgent need for research on the development of such tools at multiple scales to effectively allocate countermeasures such as negative emission technologies. We also discuss potential extensions for carbon-constrained planning in conjunction with other established tools.

Segregated targeting problems, a class of resource allocation and conservation problem, consists of a set of common internal sources and multiple sets of demands. Each set of demands, also called zone, is associated with a dedicated resource. The demands of each zone are met by the resource specified for that zone and the common internal sources. These problems are addressed in the literature for minimisation of a single objective function. However, to make sustainable and cleaner production, multi-objective optimisation plays a vital role. This paper addresses multiple objectives in a segregated targeting problem using Pinch Analysis approach. A methodology is developed in this paper which graphically identifies precisely the optimal targeting sequences and reduces the computational effort of calculating non-optimal solutions. The computational efficiency of the proposed approach is illustrated through an example. Four different illustrative examples from various domains such as water allocation networks, planning for carbon-constrained energy sectors, and integrated iron and steel mill, demonstrate the applicability of the proposed methodology. Finally, the optimal solutions of these illustrative examples are represented through the Pareto-optimal front.

Pinch analysis provides a systematic methodology for improving efficiency through enhanced process integration. Originally, the methodology focused on heat integration with heat exchanger network (...

Two lignin (moisture content: 50 wt%) conversion processes at a capacity of 200 t-wet/d were simulated to calculate the product yield, the heat and power required for the operation, leading to the balance of payment (BP), which is the income per unit weight of processed lignin. One of the studied processes was the 1,3-butadiene (1,3-BD) production process. The other process, used as a competitive process, was the gasification power generation process (GPG). For the GPG, 257,911 kWh/d of power can be sold. The 1,3-BD production process was improved by power generation using gases unavailable for 1,3-BD production and the regeneration of CO2 absorption liquid using the surplus heat through the pinch analysis. The improved ideal 1,3-BD production process can supply not only 1,3-BD (14.0 t/d) but also heat (1383 GJ/d) and power (82,577 kWh/d). When the power selling price and 1,3-BD price were changed, the 1,3-BD production process had a breakeven point for the power selling price against the GPG. The 1,3-BD production process from lignin will have higher BP than the GPG if the performance of the employed catalysts can be enhanced when taking the future power selling price into account.

Conventional diesel engine has multiple waste heat sources, which make ORC configuration selection difficult. This paper proposed an ORC configuration modification and evaluation method. Pinch analysis technique was employed to integrate multiple waste heat sources into one composite curve. We presented an optimal practical ORC (OP-ORC) that matches the composite waste heat source and the cold source. ORC configuration modification was performed by improving the thermal matching between the ORC and the heat (cold) sources. Relative efficiency, which defined as the thermal efficiency ratio of the actual ORC to the OP-ORC, was used as criterion to evaluate various modified ORC configuration. An ORC modification case for multiple waste heat sources derived from a diesel engine was presented. With the thermal efficiency of 18.57% achieved by the OP-ORC, analysis results showed that the basic preheating ORC using Cyclopentane can only achieve a thermal efficiency of 9.28%. After cycle modification, a modified ORC could obtain a thermal efficiency of 14.23%, which is significantly close to the OP-ORC with a relative efficiency of 76.6%. This method would provide researchers with information to assess the benefit and the cost about each configuration modification and determine the direction of further improvement.

In this study, pinch analysis is employed to integrate energy in steam cycle of a 250 MW thermal power plant (TPP) located in Rajasthan state of India. To apply pinch analysis on steam turbine, all extractions exiting the turbine are considered as hot utility and feedwater as cold utility. Pinch analysis shows the potential savings in hot and cold utilities as 9.66% and 0.77%, respectively. Considering heat transfer across the pinch in condenser, heat available in boiler blow down and flowrates of extraction of low pressure (LP) turbine, six different energy integration schemes are proposed. Results show that extraction of LP turbine entering to LPH-1 is eliminated, which saves steam extracted from turbine for preheating the feedwater and thus, extra power is generated. It is also seen that flowrates from other two extractions of LP turbine decrease marginally. Amongst six energy integration schemes, the best one indicates that using pinch analysis, net generated power is increased by 0.55% and demineralized water demand is reduced by 57.6%. Further, exergy analysis of steam cycle is carried out and compared with that of most suited retrofitted scheme. Results of the present study are compared well with that of published literature.

With increasing emphasis on sustainable development, developing countries are required to adapt more sustainable approaches to energy policy-making. Bioenergy supply chain planning methodologies can provide viable frameworks for policy-making. However, current methodologies lack the ability to simultaneously consider CO 2 emission reduction targets while designing a bioenergy supply chain. As such, the objective of this work is to present a hybrid methodology that combines both carbon emission pinch analysis with superstructure-based optimisation technique. The proposed methodology was demonstrated via a palm-based case study, focused on the state of Selangor, Malaysia. The case study was broken into two scenarios. The first scenario accounted for an output-driven energy policy, whereby the electricity output of the bioenergy supply chain network (BSCN) is prioritised and the corresponding emission reduction is analysed. Results from the first scenario suggests that the optimised BSCN with 5,040 TJ output could reduce CO 2 emission intensity by 9.71%. The second scenario focused on an emission-driven policy. Emission-driven policy establishes the emission reduction targets first and then determines the corresponding BSCN to achieve it. Results from this scenario indicate all oil palm plantations could afford to operate on low growth factors of up to 0.8 to avoid sharp drops in possible CO2 reductions for the BSCN. This policy was explored further by conducting sensitivity analysis on the agricultural growth and biomass export factors respectively. The analyses found that the optimised BSCN experience minimal change in costs when plantations have growth factors beyond 1.1. Lastly, analysis was performed to evaluate the range of technologies chosen based on the electricity output. The analysis found that power plant technologies were favoured more as compared to combined heat and power systems.

In this paper, we model the effects of electricity generation on multiple environmental pressures. Given the environmental considerations, we assume a decrease in the carbon footprint and adjust the energy-mix by increasing the use of renewables. We combined a footprint approach and pinch analysis to devise the optimal energy-mixes and quantify the resulting environmental impacts. The analysis focuses on the three Baltic States (Estonia, Latvia and Lithuania), which not only need to ensure sustainability of their electricity generation but also reduce the use of imported fossil fuels. The results indicate that biomass might be an appealing option for reduction of the carbon footprint in Estonia’s and Latvia’s electricity generation, whereas wind energy might be preferred in Lithuania. However, the analysis of land and water footprints suggests that further considerations are needed to treat biomass as a sustainable means for electricity generation.

Biorefineries have been widely studied during the last years and proposed as the best option to transform biomass systems into value-added products. Different methodologies have been proposed for the design of biorefineries: knowledge-based approach, early-stage approach, and superstructures, among others, which have been coupled to process improvement schemes as pinch analysis and process intensification. Regarding process design, it is necessary to ensure that the most advanced concepts are applied on the design to ensure efficient processes that direct to more sustainable processes. The processes that are currently being designed as biorefineries in many cases cannot be considered as completely efficient, because they are generally biased to designs based only in typical methods of process engineering. It is still necessary to implement further design strategies focused on increasing the efficiency and decreasing energy consumption. Multiple methods have been used for the design and improvement of chemical/biotechnological processes. Among these, shortcut methods, especially thermodynamic-topological analysis, are highlighted as a useful tool in the process engineering stage of a given process and might be useful to decrease energy consumption and to increase the efficiency since the design stage. This work proposes a design strategy for biorefineries using a shortcut method as the thermodynamic-topological analysis. For this, a biorefinery based on cocoyam, which is a rural raw material with a high potential for the obtainment of added-value products, was used as a case study. The chosen products were ethanol, lactic acid, starch, and feed additive. The biorefinery was simulated in Aspen Plus. Thermodynamic-topological analysis was implemented in the proposed biorefinery and both biorefineries (with and without the application of thermodynamic-topological analysis) were assessed in economic, environmental, efficiency, and energy-consumption terms. It was determined that the application of thermodynamic-topological analysis generated a more efficient process. After the validation of the results, it was possible to establish a design strategy for biorefineries complementing the knowledge-based approach and based on thermodynamic-topological analysis.

Chemical looping reforming is a promising option for the conversion of gaseous fuels to high quality syngas suitable for gas-to-liquids (GtL) processes. This work evaluates the potential for syngas, heat, power, and steam generation for diluent production at steam assisted gravity drainage (SAGD) facilities using low cost ilmenite ore pressurized chemical looping reforming (PCLR). Preliminary fixed-bed reactor testing on a naturally occurring Canadian ilmenite ore was performed to determine the optimal operating regime for syngas generation. Based on SEM characterization, EDX elemental mapping, XRD, and Mossbauer spectroscopy measurements it was demonstrated that partial reduction to Fe2.5+ and Fe2+ containing species is required to avoid the production of CO2. Additionally, the reduction to Fe° containing species should be minimized to limit the formation of carbon and metal carbides. These results were used to generate material and energy balances via Aspen HYSYS V9 process simulation software of the entire PCLR process for SAGD applications using a Canada’s Oil Sands Innovation Alliance (COSIA) SAGD facility template. Thorough energy integration of the combined PCLR-SAGD process using Pinch Analysis suggests that steam and diluent requirements can be met, with excess power generation, at lower costs than more traditional syngas generation technologies, while meeting CO2 emissions targets and reducing boiler feed water (BFW) make-up. Having shown that process performance is attractive, a techno-economic assessment to establish the most economical design for the PCLR-SAGD process is now required.

This study presents developed approaches that could be used for retrofitting of existing heat exchanger networks (HENs) within individual processes and industrial sites to achieve lower energy consumption, cost savings and emission reduction. Successful industrial applications are further presented, and future challenges are identified. Approaches used for retrofitting of existing HENs are based on heuristics, on thermodynamic analysis and insights – Pinch Analysis and recently developed Bridge Analysis, on numerical optimisation - Mathematical Programming, and on hybrid or combined approaches which are based on a combination of heuristics, physical insights and/or numerical optimisation. Optimisation-based approaches could be further divided into deterministic and stochastic (probabilistic) methods. Those systematic approaches (all approaches except pure heuristics) use either sequential (divided into sub-problems) or simultaneous synthesis methods.

This paper presents an optimisation method called the Product-Energy Nexus Cascade Analysis (PENCA), developed based on the principal of Pinch Analysis. Product and energy are both valuable resources that are majorly used in industrial processes. Both product and energy are interdependent where increasing product demand will increase the energy demand and vice versa. In this paper, PENCA is introduced to simultaneously optimise both product and energy system that is interdependent. The methodology applies Cascade Analysis to individually optimise both system. As both systems are interdependent, altering one of the system will result in a change to the other system. An iterative method is then introduced to converge the analysis to obtain the optimal result for both systems. A case study is conducted to prove PENCA methodology, in which biogas is used as cooking gas and used to generate electricity and for a residential area of 500 households. A typical household with a daily electricity consumption of 9 kWh and cooking gas 31.06 kWh is estimated for this study. The power plant will also produce electricity to operate the palm oil mill. The production of biogas requires electricity as well due to the presence of electrical machineries in anaerobic digestion and purification process such as pump and compressor. An overall of 4 iterations were conducted and the final capacity of the anaerobic digester is revealed as 474.180 m3 and the biogas power plant capacity is 1522.769 kWh, the biogas storage capacity is extracted and revealed as 1065.003 m3, while the energy storage capacity is 750.00 kWh.

The process of producing hydrogen and electric power from biogas and the combined hydroxyapatite (HAp) production from calcium hydroxide (Ca(OH)2), which uses a substrate of calcium. This production process also generates CO2 from the methane steam reforming (MSR) reaction and water gas shift (WGS) reaction, while the carbonation reaction then serves to capture this CO2, thus eliminating it before it reaches the atmosphere. In order to lower the production costs, simulations were carried out using the Aspen Plus software to determine how to find efficiencies in the process. Analysis using the Aspen Energy Analyzer shows that heat integration can lead to improved energy efficiency in production plants in addition to product diversification. To achieve energy integration, the process of hot and cold streams must be appropriately matched, while the introduction of utilities should occur only to balance energy consumption deficits. This study proposes a basic systematic retrofit approach based on pinch analysis (PA) to reduce the utility consumption for any kind of industrial heat exchanger network (HEN) through a new minimum temperature approach which requires only minimal capital investment. When assessing the production process following improvement of the HEN, the total costs decreased from 1.57e+06 $/year to 8.63e+05 $/year, representing an annual decline of 44.92%.

This is a review of the concepts of purpose, direction, and objective in the discipline of thermodynamics, which is a pillar of physics, natural sciences, life science, and engineering science. Reviewed is the relentless evolution of this discipline toward accounting for evolutionary design with direction, and for establishing the concept of purpose in methodologies of modeling, analysis, teaching, and design optimization. Evolution is change after change toward flow access, with direction in time, and purpose. Evolution does not have an ‘end’. In thermodynamics, purpose is already the defining feature of methods that have emerged to guide and facilitate the generation, distribution, and use of motive power, heating, and cooling: thermodynamic optimization, exergy-based methods (i.e., exergetic, exergoeconomic, and exergoenvironmental analysis), entropy generation minimization, extended exergy, environomics, thermoecology, finite time thermodynamics, pinch analysis, animal design, geophysical flow design, and constructal law. What distinguishes these approaches are the purpose and the performance evaluation used in each method.

A Chilean company dedicated to grape juice production used a 696 m2 parabolic trough collector to pre-heat the feed water of a liquefied petroleum gas boiler in a temperature range of 20–90 °C. During 2017 the solar field generated 241 MWhth of heat, a low value for a concentration collector of such dimensions located in a place with high irradiation. This study presents a methodology to identify enhanced scenarios of solar heat integration into a grape juice industry and among them select the best scenario from an energetic perspective. This methodology started with data gathering of the thermal processes of the industry and the solar field (monitoring campaign and logbook of the industry) to generate the annual thermal demand. In a second step, the maximum theoretical generation potential of the solar field (1,107 MWhth) was obtained with simulations in TRNSYS 18. Then, a Pinch Analysis to the process streams was performed to confirm that a higher solar heat integration potential (520 MWhth) existed. The next step consisted of identifying different scenarios to increase the solar heat integration and analyzing them with simulations in TRNSYS 18 to identify the best-case scenario. The main increase on the solar fraction was achieved for the scenario when the collector working temperature was increased up to 140 °C and when heat was integrated at process level. Furthermore, it was concluded that one of the reasons for low solar fraction was the low thermal demand during months with high solar irradiation.

A novel route for the direct one-pot oxidation of ethanol to ethylene oxide has been designed and scaled-up into a full process: this is the very first design of an innovative one-step conversion route from bioethanol to ethylene oxide. Starting from the review and interpolation of reaction kinetics, a staged, cooled reactor is sized for the air-based oxidation of bioethanol, yielding ethylene oxide in one-step. An efficient strategy for the separation of the product from the gas phase effluent of the reactor is developed, based on absorption in a hydro-alcoholic solution rather than in pure water. This in turn brings a material recycle between the feed and purification section that benefits the atom economy. As the basis of an economic analysis, the energy balances are assessed and analyzed via the Pinch Analysis method. The calculations let foresee a conversion of 90% of bioethanol into Ethylene Oxide (> 99% purity) and 7.7% into marketable ethylene-glycol.

Hydrothermal liquefaction (HTL) is an advanced biomass conversion process for biocrude production from a broad variety of organic feedstock, including wet waste streams. The intermediate biocrudes can be further upgraded to liquid hydrocarbon fuels and thereby contribute to the mitigation of greenhouse gases from the transport sector. This work investigates an optimized sub-system integration of transportation fuel production via sub-critical HTL of primary sewage sludge. The plant design integrates HTL conversion, biocrude upgrading via hydrotreatment, and an energetic valorization of the residual aqueous phase from HTL conversion via catalytic hydrothermal gasification (cHTG). The option of on-site hydrogen production via reforming of cHTG gas is examined for the purpose of biocrude upgrading. The modeling results show that the hydrogen demand for hydrotreatment could be covered by the valorization of the HTL by-products. The thermal management of an integrated biofuel plant is optimized with respect to subsystem cost based on in-depth process modeling to quantify mass and energy flows and principles of pinch analysis to design a heat exchanger network. The cost optimized configuration results in an overall process energy efficiency of 40.5%. The results provide a basis for design choices for future HTL plants.

The number of large-scale heat pumps (HP) implemented in Danish district heating networks has increased in recent years. The installations are often custom-made solutions designed carefully to obtain a high Coefficient of Performance (COP). This study aims at quantifying and compare five approaches for improving the COP of a heat pump, with a one-stage ammonia cycle used as the reference case with sink temperatures of 50 °C/80 °C (in/out) and source temperatures of 10 °C/3 °C. The approaches include increased complexity of cycle layout, optimization of intermediate pressure in two-stage cycles, a connection of HP cycles in series, optimization of load share between heating capacity for HPs in series, and optimal design of heat exchanger networks (HEN). The latter is based on an implementation of pinch analysis to HP HENs. The results revealed an improvement in COP by +15.8% obtained with increased complexity of cycle layout (two-stage cycle with a low-stage desuperheater) compared to a COP of 2.98 for the reference case. Connecting up to three one-stage HPs and two-stage cycles in series improved COP by 4.42% and 24.5%, respectively. The benefit of optimal load share and intermediate pressure was less than 0.5 % points for all configurations compared to reference values based on theoretical approaches. Exploiting the potential for optimal HEN increased the potential to 10.4% for one-stage cycles in series and nearly 29% for two-stage cycles increasing the COP to a maximum of 3.84.

Rising awareness for the environment as well as concerns over the sustainability of fossil fuels has encouraged developed and developing countries to find alternative ways to enhance the thermal efficiency of current power systems. The thermal efficiency of power plants can be increased from 30 – 40 % up to 80 – 90 % through the implementation of a trigeneration system by recovering dissipated waste heat for other purposes. The trigeneration system can be defined as a technology that can produce simultaneous power, heating, and cooling energy from the same fuel source. Trigeneration System Cascade Analysis (TriGenSCA) methodology is an optimisation approach based on Pinch Analysis that has been used to establish the guidelines or the proper size of the trigeneration system. This paper proposes a modification of TriGenSCA by considering a multi-period of energy consumption to optimise the size of the utility in the centralised trigeneration system by considering the transmission and storage of energy losses in the Total Site system. There are six steps involved including data extraction, identification of time slices, Problem Table Algorithm (PTA), Multiple Utility Problem Table Algorithm (MU PTA), Total Site Problem Table Algorithm (TS PTA), and modified TriGenSCA. The methodology has been tested on the centralised nuclear trigeneration system in a Total Site System as a case study and results shown that thermal energy needed by the Pressurized Water Reactor (PWR) trigeneration system with transmission losses is 2,427 MW whereas thermal energy needed by the PWR trigeneration system without transmission losses is 2,424 MW. The TriGenSCA with consideration of transmission and storage energy losses is useful for engineers and designers to determine the exact value of energy for trigeneration plant.

Hybrid energy systems have been widely used for residential and industrial purposes. In this system, the total energy requirement of each unit can be met with heat and electricity. Pinch Analysis becomes a widely used tool for Process Integration, and using Pinch Analysis for Heat Integration is well-established. However, for the combined heat and power system, the theory and the corresponding tool deserve some more development. This paper extended the Pinch Analysis concept and proposed a Heat and Power Pinch Analysis to target the amount of heat that should be recovered from the hybrid energy system. Heat and Power Composite Curve (HPCC) is developed to visualise the total energy and the separated heat and power (electricity) requirement of a hybrid energy system in a working time period. The amount of outsourced electricity that should be purchased, and stored electricity at the startup period, and the extra electricity generated by the system at the end of the working period can be demonstrated. A case is studied to illustrate the steps of using this tool, two scenarios are discussed, and the targets are shown.