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This study uses the application of Pinch analysis to optimize an integrated electrolyzer and methanation system, a promising approach for producing green hydrogen and synthetic natural gas (SNG). By leveraging renewable energy sources, such as wind and solar, electrolysis is used to produce hydrogen, which reacts with captured carbon dioxide in the methanation reactor to form methane. This process not only allows for efficient energy storage but also supports the reduction of greenhouse gas emissions. A key focus of this study is the optimization of thermal energy flows within the system, which has not been extensively addressed in the literature. Pinch analysis was applied to identify the critical Pinch point, which revealed the temperature at which the most efficient heat recovery could be achieved. The design of a tailored heat exchanger network led to significant improvements, including a 66.45% reduction in hot utility consumption and an 18.85% reduction in cold utility demand. Overall, the system achieved global energy savings of 31.02%. These results were compared with the existing literature, demonstrating that our approach offers comparable or superior utility savings while addressing challenges, such as the complexity of chemical reactions and system integration. This research highlights the potential for substantial operational cost reductions and increasing sustainability in industrial applications, contributing to the advancement of renewable energy technologies and the decarbonization of energy systems. [ABSTRACT FROM AUTHOR]

The swift expansion of the global population and economy has spurred growing requirements for energy and water in recent decades. Inefficient energy and water consumption, however, has led to an increase in CO2 emissions. Hence, the socio-economic development of a country must consider the interconnections between energy, water and carbon, as there are mutual dependencies among these three elements. This work considers the nexus between energy, water and carbon in the design of integrated energy–water systems using a new automated targeting modeling (ATM) framework. ATM incorporates the advantages of the insight-based Pinch method and a mathematical programming approach to provide visual understanding for a thorough analysis of the problem while guaranteeing accurate solutions. Minimum targets of power and water based on the integrated network operation were established by the ATM, with corresponding carbon emissions. A specific goal of annual carbon emissions reduction was set as the constraint and the ATM optimized the capacities of the components in the system accordingly to achieve minimum overall cost. The application of ATM on an industrial plant case study shows that a target of 45% reduction in the carbon discharge amount was achieved by shifting to greener fuel in the energy system at a minimum overall cost increase of 0.45% only. The framework can assist users in meeting power and water loads in their plant while planning for the appropriate decarbonization efforts at the minimum possible cost. [ABSTRACT FROM AUTHOR]

Spray drying is an energy-intensive process in industrial use, making energy recovery a critical focus for improving overall efficiency. This study investigates the potential of integrating heat-recovery systems, including an innovative air reheater, into a closed-loop spray-drying unit to maximise energy savings. Through detailed pinch analysis, the system achieved a very low approach temperature, averaging 3.48 K, which is significantly lower than that of conventional open-loop systems. The study quantifies the energy-recovery potential by demonstrating that the integration of heat-recovery components can reduce the external heating demand by up to 30%. This not only enhances heat-transfer efficiency but also lowers operational costs and reduces the system's environmental impact. The results suggest that closed-loop systems with air reheaters offer a scalable solution for improving energy efficiency across different industrial applications. The research highlights a new paradigm: focusing on latent energy within the system rather than adjusting individual operational variables. [ABSTRACT FROM AUTHOR]

The process integration and electrification concept has significant potential to support the industrial transition to low- and net-zero-carbon process heating. This increasingly essential concept requires an expanded set of process analysis tools to fully comprehend the interplay of heat recovery and process electrification (e.g., heat pumping). In this paper, new Exergy Pinch Analysis tools and methods are proposed that can set lower bound work targets by acutely balancing process heat recovery and heat pumping. As part of the analysis, net energy and exergy load curves enable visualization of energy and exergy surpluses and deficits. As extensions to the grand composite curve in conventional Pinch Analysis, these curves enable examination of different pocket-cutting strategies, revealing their distinct impacts on heat, exergy, and work targets. Demonstrated via case studies on a spray dryer and an evaporator, the exergy analysis targets net shaft-work correctly. In the evaporator case study, the analysis points to the heat recovery pockets playing an essential role in reducing the work target by 25.7%. The findings offer substantial potential for improved industrial energy management, providing a robust framework for engineers to enhance industrial process and energy sustainability. [ABSTRACT FROM AUTHOR]

In this research, the simulation of an existing 31.5 MW steam power plant, providing both electricity for the national grid and hot utility for the related sugar factory, was performed by means of ProSimPlus® v. 3.7.6. The purpose of this study is to analyze the steam turbine operating parameters by means of the exergy concept with a pinch-based technique in order to assess the overall energy performance and losses that occur in the power plant. The combined pinch and exergy analysis (CPEA) initially focuses on the depiction of the hot and cold composite curves (HCCCs) of the steam cycle to evaluate the energy and exergy requirements. Based on the minimal approach temperature difference (∆Tlm) required for effective heat transfer, the exergy loss that raises the heat demand (heat duty) for power generation can be quantitatively assessed. The exergy composite curves focus on the potential for fuel saving throughout the cycle with respect to three possible operating modes and evaluates opportunities for heat pumping in the process. Well-established tools, such as balanced exergy composite curves, are used to visualize exergy losses in each process unit and utility heat exchangers. The outcome of the combined exergy–pinch analysis reveals that energy savings of up to 83.44 MW may be realized by lowering exergy destruction in the cogeneration plant according to the operating scenario. [ABSTRACT FROM AUTHOR]

In this research work, an attempt has been made to address the heat and power integration opportunities for the process of the chlorination of benzene. This process produces a mixture of chlorobenzenes. To increase the production of the dichlorobenzene portion, the ratio of chlorine to benzene is typically 2:1. A process simulation model is designed using Aspen Plus for the production of 70,000 tons/year of dichlorobenzene via the reaction of liquid benzene with gaseous chlorine. Energy analysis is performed for the effective utilization of the utilities by networking the heat exchangers. This modification reduced the process heating and cooling requirements by 56.7% and 12.7%, respectively, and a reduction by 35.4% in the operating costs is achieved, while the annualized fixed cost increased by 9.6%; these changes resulted in savings in the total annual costs of about 10.9%. [ABSTRACT FROM AUTHOR]

It is important to estimate the energy required in ore processing to select the most affordable and efficient energy system for the integration of renewable resources into the mining industry. In the present work, the energy consumption for the concentrate of tungsten ore in Mongolia was theoretically predicted based on operational variations (particle size and the hardness of the tungsten ore) and different equipment. The energy was in the range from 0.48 to 1.32 kWh/t for the crushing stage, and a cone crusher was more suitable than a jaw crusher due to the particle size of feed material and product. The required energy in the grinding stage was from 6.22 to 11.88 kWh/t using a SAG mill or from 3.04 to 7.39 kWh/t using a ball mill. The further separation by a flotation consumed 4.83 kWh/t or by a shaking table consumed 1.29 kWh/t. The maximum energy consumption per hour for the whole process was estimated to be 2–3 MW, which was better to integrate with a hybrid renewable energy system. The sizing method Power Pinch Analysis was used to estimate the electric supply based on the combination of wind, biomass and solar resources, which was sufficient for the demand from the predicted range of energy. [ABSTRACT FROM AUTHOR]

Ventilation heat loss is one of the most important factors contributing to energy performance of greenhouses. This paper suggests a systematic method based on dynamic pinch analysis (PA) to design an integrated heating, cooling, and ventilation system that uses ventilation waste heat in a cost-effective and energy efficient way. A heat recovery system including an air handling unit, borehole thermal storage, and a heat pump is proposed to investigate all heat integration scenarios for an entire year. In the first step, the heat integration scenarios are reduced to a few typical days using a clustering technique. Then, a generic methodology for designing a heat exchanger network (HEN) for a dynamic system, ensuring both direct and indirect heat recovery, is presented and a set of HENs are designed according to the conditions of typical days. Afterwards, the best HEN design is selected among all design alternatives using a techno-economic analysis. The whole procedure is applied to a commercial greenhouse and the best HEN configuration and required equipment sizes are calculated. It is shown that the best-performing design for the greenhouse under study produces primary energy savings of 57%, resulting in the shortest payback period of 9.5 years among all design alternatives. [ABSTRACT FROM AUTHOR]

Bioadsorbents based on biopolymers modified with magnetic nanoparticles stand out for being non-toxic, effective, and easy to recover. Thus, the objective of the present work was to carry out a computer-aided environmental evaluation of the industrial-scale production of bioadsorbents from chitosan modified with iron nanoparticles and functionalized with thiourea as a chelating agent plus mass integration. The plant simulation was carried out in Aspen Plus, and for the mass integration of the process, a pinch analysis was used to determine the minimum target fresh and residual water amount, assuming two process stages: (1) the synthesis of magnetite nanoparticles, and (2) the production of chitosan-based bioadsorbents. The environmental assessment was performed using the waste reduction algorithm (WAR). The potential environmental impact (PEI) was quantified, taking into account the impact of the products and energy, obtaining a value below zero of −0.78 PEI/kg of the product. The photochemical oxidation potential (PCOP) stood out as the category with the greatest impact, mainly related to the use of ethanol during washing. The categories related to toxicological impacts (HTPI, HTPE, TTP, and ATP) had lower values than those related to atmospheric impacts (GWP, ODP, PCOP, and AP). The mass integration of the process resulted in fewer impacts in the HTPE category, as a consequence of the decrease in NaOH in the residual streams and the release of 0.297 PEI/kg of product in the ATP category caused by the presence of Al(OH)₃. It can be concluded that the mass integration managed to reduce up to 51% of the freshwater used in the processes, and it is a useful tool, as it slightly decreased the total potential impacts. [ABSTRACT FROM AUTHOR]

The Paris agreement in 2015 has required that countries commit to global carbon emission reduction by setting their national targets. In most countries, the electricity sector is identified as one of the major contributors to carbon emissions. Therefore, the governments count on decarbonizing the electricity sector to achieve their carbon reduction targets. However, this could be challenging as it is complex and involves multi-stakeholders in implementing the decarbonization plan. This work presents a mathematical optimization model to determine multi-period electricity generation planning to achieve the electricity demand and the carbon reduction target. A multi-period analysis allows long-term planning for decarbonizing the electricity sector by the gradual phasing out of coal-based power plants and the introduction of renewable-based electricity generation. To illustrate the proposed approach, the developed model is solved to strategize low-carbon energy transition planning for the Sarawak region in Malaysia. The model determines the optimal amount of new renewables required during each of the time periods, from 2020–2040, to meet the carbon reduction target. The optimal results are generated under two scenarios—no co-firing and co-firing. The generated results show that the co-firing scenario resulted in a 14.09% reduction in new renewable additions and a 5.78% reduction in the total costs. The results also determined a 66% reduction in coal consumption in 2050 when compared to the base year in 2020. [ABSTRACT FROM AUTHOR]

Uncertainties are widely present in the design and simulation of aero-engine combustion systems. Common non-probabilistic convex models are only capable of processing independent or correlated uncertainty variables, while conventional precise probabilistic sensitivity analysis based on ideal conditions also fails due to the presence of uncertainties. Given the above-described problem, an imprecise p-box sensitivity analysis method is proposed in this study in accordance with a multi-dimensional parallelepiped model, comprising independent and correlated variables in a unified framework to effectively address complex hybrid uncertainty problems where the two variables co-exist. The concepts of the correlation angle and correlation coefficient of any two parameters are defined. A multi-dimensional parallelepiped model is built as the uncertainty domain based on the marginal intervals and correlation characteristics of all parameters. The correlated variables in the initial parameter space are converted into independent variables in the affine space by introducing an affine coordinate system. Significant and minor variables are filtered out through imprecise sensitivity analysis using pinching methods based on p-box characterization. The feasibility and accuracy of the method are verified based on the analysis of the numerical example and the outlet temperature distribution factor. As indicated by the results, the coupling between the variables can be significantly characterized using a multi-dimensional parallelepiped model, and a notable difference exists in the sensitivity ranking compared with considering only the independence of the variables, in which input parameters (e.g., inlet and outlet pressure, density, and reference flow rate) are highly sensitive to changes in the outlet temperature distribution factor. Furthermore, the structural parameters of the flame cylinder exert a secondary effect. [ABSTRACT FROM AUTHOR]

To improve energy efficiency and to recover energy, various mathematical models, such as pinch analysis, entropy analysis, exergy analysis, and entransy analysis, have been established to analyze heat transfer networks. In this study, these methods were applied to analyze the energy-saving effect of the epichlorohydrin unit in a certain enterprise. The results showed that when the minimum heat transfer temperature difference (ΔTmin) was 10K, 15K, and 20K, the efficiencies of the second law of thermodynamics calculated by entropy analysis were 88.02%, 93.52%, and 99.49%, respectively. The analytical method calculated an efficiency of 61.01%, 59.28%, and 57.27%, respectively, with public works' savings of 16.59%, 14.86%, and 12.02%. The pinch analysis method achieved public works' savings of 22.80%, 21.50%, and 19.35%. The entransy analysis method calculated an entransy transfer efficiency of 42.81%, 42.13%, and 41.00%, respectively, with public works' savings of 19.41%, 18.01%, and 15.70%. Based on the results, entropy analysis was found to be contrary to the principle of minimum entropy production. Exergy analysis was not able to establish a heat transfer network. The pinch analysis method was not suitable for determining the thermal efficiency of a heat transfer network as the criterion for evaluating energy saving. On the other hand, the entransy analysis method was able to establish a heat transfer network and evaluate the heat utilization of the network by entransy transfer efficiency. Overall, the data analysis was reasonable. [ABSTRACT FROM AUTHOR]

Pinch analysis is vital in optimizing heat exchanger networks (HENs). Targeting methods are used when determining cost effectiveness with pinch analysis. However, the existing targeting methods for the capital cost of HEN are not suitable for wide application scenarios. Therefore, we developed a high-accuracy general capital-cost-targeting method. It is built on a final structure that was evolved from the spaghetti structure of HEN through four loop elimination stages. This structure helps to reduce the prediction deviation of the method. To achieve high adaptability while establishing this method, we considered the different heat exchanger cost categories, different cost laws for one stream pair, and area limitations of heat exchangers that may be encountered in practice. In addition, allowing streams to use individual temperature difference contributions enhances the method's predictive capacity. The potential defects of the method found in numerical experiments and case studies were corrected with improvement measures. As a result, the accuracy and stability of the targeting method were further enhanced, with absolute target deviations generally within 10% and often within 5%. This study provides a benchmark for the optimal capital cost of HEN, allowing for a better economic effect when applying pinch analysis. [ABSTRACT FROM AUTHOR]

The main goal of this study is to evaluate possible reuse routes of effluents from adairy plant. First, the water flow in the plant was evaluated. All water consumed and effluents generated by the industrial process were quantified and characterized. In addition, the water quality parameters required for different industrial activities were assessed. Secondly, a treatment system using a membrane bioreactor and a nanofiltration reactor, from a study previously conducted by the authors, was considered. Then, a water pinch analysis was carried out through the application of the collected data using the Water Pinch software. Both direct reuse/recycle and regeneration schemes were investigated. In this context, although the direct reuse/recycle of effluents were shown to be able to reduce the freshwater use for the clean-in-place process (CIP) by 33.4%; the schemes with the regeneration of the effluents showed up to 66.7% and 95.4% of freshwater reduction for the CIP and general processes, respectively. Finally, four water reuse routes were proposed. The proposed route combining the most advanced treatment technologies studied showed the best performance in terms of reduction of the total freshwater consumption (69.5%) in the dairy plant. [ABSTRACT FROM AUTHOR]

Integrated energy–water systems have been explored using different process integration techniques considering the energy–water–carbon nexus to minimize the carbon footprint, e.g., pinch analysis techniques (power cascade table, water cascade table, and energy planning pinch diagram). However, the power and water losses while considering the energy–water–carbon nexus have not been explored in detail in the previous works. This work focuses on the modifications of the existing pinch analysis methods for energy–water–carbon nexus study while considering power and water losses, for an optimized energy–water system. Power and water losses should not be neglected in the analysis as they have a significant impact on the carbon emissions and overall capacities of energy and water. The effect of losses on energy storage capacity, outsourced electricity, water supply volume and water storage capacity were evaluated on an industrial case study. Results from the case study demonstrate that, while considering power losses during power allocation can lower storage capacity, it tends to raise the needed outsourced electricity supply. As water supply volume tends to increase, the water storage capacity tends to decline when losses are considered. The results were compared to the data without losses, and it was observed that the storage capacity of energy decreases by 4% while outsourced energy increases by 6%. Water supply volume increases by 20% but water storage capacity decreases by 13.7%. The emissions from energy system remains same while from the water system the emissions rise significantly by 20%. It is expected that consumers that takes power and water losses into account will produce more realistic and reliable energy, water, and carbon reduction targets and prevent under-sizing issues in designing integrated energy–water systems. [ABSTRACT FROM AUTHOR]

Methanol and ammonia are important chemical materials in the chemical industry. During the production of methanol and ammonia, a large amount of waste heat is released. The waste heat can be used to save energy and reduce CO2 emissions. In this study, pinch analysis is used to design the heat exchanger network (HEN) of pulverized coke (PC) chemical looping gasification coupled with coke-oven gas (COG) to methanol and ammonia (PCCLHG-CGTMA). The heat integration process is accomplished in two ways, as mentioned below. (1) The HENs in each of the three heat exchange units are designed individually; (2) the HENs of the three heat exchange units are treated as a whole and designed simultaneously. Compared to the HEN designed individually, when the HENs are designed as a whole, a total of 112.12 MW of hot and cold utilities are saved. In the HENs designed as a whole, the reduction in operating cost is sufficient to offset the increase in capital cost; the total annual cost (TAC) is reduced by 10.9%. These results reveal that the HENs designed as a whole have more scope for energy saving, which can be a reference for new HEN design and modification to realize more heat recovery and lower investment. [ABSTRACT FROM AUTHOR]

Improving the energy efficiency in heat exchanger networks (HENs) remains a significant industrial problem, specifically in energy-intensive operations. A particular method for such an objective is the modification of HENs at the equipment-use level, where structural changes take place and units within the network are moved, replaced and/or removed. This practice is usually known as retrofit. The objective of a retrofit is to maximize the heat recovery using the minimum modifications possible and minimum retrofit cost. Traditional retrofit techniques would normally consider one type of heat exchanger (based on the original network) with no additional design features (i.e., heat transfer enhancement technologies). The expansion of such alternatives is limited by practical use and availability of theoretical methods. In this context, the inclusion of high-performance heat exchangers such as plate heat exchangers (PHEs) has not been widely explored, even when their design and operational advantages are known. In this work, a new step-by-step automated HENs retrofit approach based on Pinch Analysis is proposed. The approach is possible to identify the best modification, its location within the network, and its cost simultaneously. Moreover, to increase energy savings, this work presents a strategy that seeks to utilize high efficiency heat exchangers such as plate heat exchangers for retrofit. A distinctive feature of this new method is the ability to handle different minimum approach temperatures, given the different types of exchangers, within the optimization of HENs. Three cases are studied using this methodology to quantify the potential benefits of including PHEs in HEN retrofits, via the analysis of the retrofit cost. Results are compared with a baseline consisting in the same network, where only Shell-and-Tube-Heat-Exchangers (STHXs) are used. In addition, the results demonstrate that this methodology is flexible enough to be applied in a wide range of retrofit problems. [ABSTRACT FROM AUTHOR]

The tobacco industry is an important contributor to realizing the carbon reduction goal. Less attention is paid to the carbon emissions of the tobacco industry. The tobacco production system is generally a carbon sink, where carbon sequestration by photosynthesis in tobacco planting and by soil are sufficient to offset the carbon emissions of the tobacco production system. This work proposed an integrated framework of life-cycle assessment (LCA) and Source-Sink Model to determine the optimal allocation of carbon sources to sinks with the objective of maximizing the profitable external benefits. From an economic perspective, internal carbon sources could be offset by the internal carbon sink of the tobacco production system. The additional internal carbon sinks can be transferred in the form of carbon trading, increasing external revenue. A case-study tobacco manufacturing plant in Sichuan, China, was chosen to demonstrate the feasibility of the proposed work. This study assesses the carbon footprint and economic benefits of a tobacco industry supply chain case (from tobacco cultivation to finished product) and analyzes the energy restructuring of different percentages of renewable energy to replace thermal power. The objective of the study is to maximise the offsetting of carbon emissions from the tobacco production system, while achieving optimal internal costs and profitable external benefits. [ABSTRACT FROM AUTHOR]

Reactive dyeing is primarily used in the textile industry to achieve a high level of productivity for high-quality products. This method requires heating a large amount of freshwater for dyeing and cooling for the biological treatment of discharged wastewater. If the heat of the wastewater discharged from the textile industry is recovered, energy used for heating freshwater and cooling wastewater can be significantly reduced. However, the energy efficiency of this industry remains low, owing to the limited use of waste heat. Hence, this study suggested a cost-optimal heat exchanger network (HEN) in a heat pump-assisted textile industry wastewater heat recovery system with maximizing energy efficiency simultaneously. A novel two-step approach was suggested to develop the optimal HEN in heat pump-assisted textile industry wastewater heat recovery system. In the first step, the system was designed to integrate the heat exchanger and heat pump to recover waste heat effectively. In the second step, the HEN in the newly developed system was retrofitted using super-targeted pinch analysis to minimize cost and maximize energy efficiency simultaneously. As a result, the proposed wastewater heat recovery system reduced the total annualized cost by up to 43.07% as compared to the conventional textile industry lacking a wastewater heat recovery system. These findings may facilitate economic and environmental improvements in the textile industry. [ABSTRACT FROM AUTHOR]

In addition to the consumption of hot utilities, there is also a significant cost associated with the consumption of cold utilities when there is a high demand for cooling. A promising solution for cooling is an absorption chiller (AC), which uses heat instead of electricity for cooling. A thermodynamic approach for evaluating AC integrated with a process is presented in this work. A model for assessing the properties and duties of an AC cycle was developed. The integration of a combined process-AC system was evaluated using the Grand Composite Curve. Three different options of integration were analyzed: (i) above the Pinch, (ii) below the Pinch, and (iii) across the Pinch. AC represents the combined effect of a heat engine and a heat pump, as the generator together with the absorber and condenser has the function of a heat engine, while the evaporator combined with the absorber and condenser mimics the function of a heat pump. The comparison between the non-integrated and integrated process-AC systems has revealed that the proper placement of AC is across or below the Pinch and the improper is above the Pinch. If AC was entirely integrated below the Pinch, the integration would result in a complete (100%) reduction in the consumption of hot utility for the operation of AC. The most suitable placement of AC with double reduction of hot utility consumption and complete reduction of both hot and cold utility to operate AC is across the Pinch due to the pumping of heat through AC from below to above the Pinch. [ABSTRACT FROM AUTHOR]

Biomass has gained global attention as one of the most important renewable energy resources that reduces greenhouse gas emissions. Various research works have been dedicated to biomass supply chain in the past decade as to continuously support the deployment of biomass resources for regional applications. In this work, a novel graphical method based on process integration is proposed for targeting the amount of biomass resources needed for a power generation problem. Apart from having a good visualized interface, the graphical method provides good insights to stakeholders on the macro-level planning of biomass allocation. Two examples are solved to demonstrate the newly proposed methods. [ABSTRACT FROM AUTHOR]

Economic criteria have prevailed in studies on integration of renewable energies. Tons of dangerous emissions are emitted by a biomass fuel, causing negative impacts over atmosphere and health. Current research proposes Pinch Analysis of solar thermal energy and the joint use of biomass (sugarcane bagasse) to produce heat and power in a Caribbean sugar mill; measuring emissions like: carbon oxide C O , carbon dioxide C O 2 , dinitrogen monoxide N 2 O , nitrogen oxides N O x , sulfur oxides S O x , non-methane volatile organic compounds NMVOC, methane C H 4 , and particulate matters, to have a global and clear view of the impacts of biomass as a renewable fuel. Variables like kWh cost, the installation and device area of renewable energy, and greenhouse gas emissions, are analysed to assess the effect on the integration final design, the target of which is to control the use of biomass. It is possible to produce an economically competitive integration design of solar system L C O E t h   s o l a r = 0.0636 USD/kWh, L C O E e l e = 0.1392 USD/kWh), zero greenhouse gases emissions (Δ T m i n r e w = 7   ° C ), and deletion of 378,711.53 t/year of C O 2 and 9567.56 t/year of solid particles. There are many possibilities that can implemented; in one of them, bagasse burning is reduced by 30% and the solar collector network for required power production is reduced by 68%. [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]

District heating systems are almost always located in densely populated urban areas where various heat sources are available, such as cooling and refrigeration systems in supermarkets, shopping malls, and power transformers. These urban sources often have a large share of waste heat, which is usually emitted into the environment. This waste heat could be used to partially cover the thermal load in district heating systems. The biggest challenge for their integration is the spatial distribution of urban heat sources in relation to the existing heat network and the temporal distribution of the availability of waste heat energy throughout the year. In this paper, we have developed an economic assessment model for the integration of urban heat sources into existing district heating systems. By the hourly merit order of waste heat utilization technologies based on pinch analysis, we have defined the most suitable integration of urban heat sources into existing district heating systems. Different temperature regimes of the urban source and the existing heat network have been considered. Finally, the method was tested on the case study of a supermarket and power substation located in Zagreb, while the sensitivity analysis was carried out with a focus on various technical and economic boundary conditions. [ABSTRACT FROM AUTHOR]

The Claus process is one of the promising technologies for acid gas processing and sulfur recovery. Hydrogen sulfide primarily exists as a byproduct in the gas processing unit. It must be removed from natural gas. The Environmental Protection Agency (EPA) notices that increasing SO2 and CO2 in the air harms the environment. Sulfur generally has an elemental content of 0.1–6 wt % in crude oil, but the value could be higher than 14% for some crude oils and asphalts. It produces SO2 and CO2 gases, which damage the environment and atmosphere of the earth, called primary pollutants. When SO2 gas is reacted with water in the atmosphere, it causes sulphur and nitric acid, called a secondary pollutant. The world countries started desulphurization in 1962 to reduce the amount of sulfur in petroleum products. In this research, the Claus process was modeled in Aspen Plus software (AspenTech, Bedford, MA, USA) and industrial data validated it. The Peng–Robinson method is used for the simulation of hydrocarbon components. The influence of oxygen gas concentration, furnace temperature, the temperature of the first catalytic reactor, and temperature of the second catalytic reactor on the Claus process were studied. The first objective of the research is process modeling and simulation of a chemical process. The second objective is optimizing the process. The optimization tool in the Aspen Plus is used to obtain the best operating parameters. The optimization results show that sulfur recovery increased to 18%. Parametric analysis is studied regarding operating parameters and design parameters for increased production of sulfur. Due to pinch analysis on the Claus process, the operating cost of the heat exchangers is reduced to 40%. The third objective is the cost analysis of the process. Before optimization, it is shown that the production of sulfur recovery increased. In addition, the recovery of sulfur from hydrogen sulfide gas also increased. After optimizing the process, it is shown that the cost of heating and cooling utilities is reduced. In addition, the size of equipment is reduced. The optimization causes 2.5% of the profit on cost analysis. [ABSTRACT FROM AUTHOR]

Geothermal energy is a sustainable renewable source of energy. The installed capacity of geothermal energy in Kenya is 847.4 MWe of the total 2.7 GWe. This paper presents the effect of six different working fluids to optimize the geothermal of 21.5 MWe of reinjected brine at a single-flash power plant in Kenya. Engineering Equation Solver (EES) code was used to design and optimize simple organic Rankine (ORC) and regenerative cycles. The objective was to combine pinch point analysis and exergy analysis for the optimum utilization of geothermal energy by varying the turbine inlet pressure, pinch point, and reinjection temperature. The turbine inlet pressures, and pinch points were varied to obtain optimum pressures for higher net power output and exergy efficiencies. As the pressure increased, the efficiencies and net power generated increase to optimal at turbine inlet pressures between 2000 and 3000 kPa. By maintaining a condenser temperature at 46.7 °C, the turbine outlet pressures were 557.5 kPa for isobutene, 627.4 kPa for isobutane, 543.7 kPa for butene, 438.9 kPa for trans-2-butene, 412.3 kPa for R236ea, and 622.9 kPa for R142b. For the pinch point of 10 °C, the working fluid with a lower net power is trans-2-butene at 5936 kW for a flow rate of 138.8 kg/s and the highest reinjection at 89.05 °C. On the other hand, R236ae had a flow rate of 398.2 kg/s, a higher power output of 7273 kW, and the lowest reinjection temperature of 73.47 °C for a 5 °C pinch point. In the pinch point consideration, the suitable fluid will depend on the best reinjection temperatures. The pinch point affects the heat transfer rates and effectiveness in the heat exchangers. The best pinch point is 10 °C, since the reinjection temperatures are the highest between 83 and 89 °C. The analysis showed that for unlimited reinjection temperatures, basic ORC is suitable. The regenerative cycle would be best suited where reinjection temperature is constrained by brine geochemistry. [ABSTRACT FROM AUTHOR]

Environmental problems are frequently related to energy use, estimated to grow at 1.6% per year until 2035. The transport sector accounts for 30% of energy demand and aviation is growing around 2.6% per year. Thus, low-emissions policies promote the use of sustainable aviation fuels. This work simulates a gasification and Fischer-Tropsch process to obtain biojet fuel from biomass and plastic waste. Syngas obtained through cogasification is purified by amine scrubbing and subjected to a Fischer-Tropsch process to produce hydrocarbons, which are upgraded for optimal fuel properties. Pinch analysis is applied to minimize energy usage, while Rankine cycles and a cooling tower are designed to cover the demand of electricity and cooling water. Results show that mass yields of the process towards biofuels are 13.06%, with an output of 1697.45 kg/h of biojet fuel. Density, kinematic viscosity, pour and flammability points and the lower calorific value of the biojet fuel comply with the ASTM D7566 standard. Pinch analysis allows to reduce 41.58% and 100% of cooling and heating demands, respectively, using biomass as renewable energy for heating. Moreover, steam generation covers 38.73% of the required electricity. The produced biojet fuel emits 20.14 gCO2eq/MJ and has a minimum selling price of 1.37 EUR/L. [ABSTRACT FROM AUTHOR]

Empty fruit bunch, a significant by-product of the palm oil industry, represents a tremendous and hitherto neglected renewable energy resource for many countries in South East Asia and Sub-Saharan Africa. The design and simulation of a plant producing pure hydrogen through autothermal reforming (ATR) of palm empty fruit bunch (PEFB) was carried out based on successful laboratory experiments of the core process. The bio-oil feed to the ATR stage was represented in the experiments and in the simulation by a surrogate bio-oil mixture of 11 organic compounds shown to be main constituents of PEFB oil from previous work, and whose combined elemental composition and volatility was determined to be as close as possible to that of the real PEFB bio-oil. The experiments confirmed that H2 yields close to equilibrium predictions were achievable using an in-house synthetised Rh-Al2O3 catalyst in a packed bed reactor. Initial sensitivity analysis on the plant revealed that feed molar steam to carbon ratio should not exceed 3 for the optimal design of the ATR hydrogen production plant. An overall plant efficiency of 39.4% was obtained for the initial design, this value was improved to 67.5% by applying pinch analysis to enhance the integration of heat in the design. The proposed design renders CO2 savings of about 0.56 kg per kg of raw PEFB processed. The proposed design and accompanying experimental studies together make a strong case on the possibility of polygeneration of H2, heat, and power from an otherwise discarded agricultural waste. [ABSTRACT FROM AUTHOR]

This paper presents both the results of a study of the existing heat exchanger network (HEN) of an industrial unit for ethylbenzene (EB) production by the alkylation of benzene with ethylene, and an analysis of four different HEN retrofit projects carried out using process integration methods. The project of modernization of HEN was carried out using classical methods of Pinch analysis. For this case, the value of ΔTmin is determined, which is limited by the technological conditions of the process. Additionally, two different heat pump (HP) integration options and the joint retrofit Pinch project with HP integration are under consideration. The economic analysis of each of the projects was carried out. It is shown that the best results will be obtained when implementing the joint project. As a result, steam consumption will be reduced by 34% and carbon dioxide emissions will be decreased by the same amount. [ABSTRACT FROM AUTHOR]

The conservation and proper management of natural resources constitute one of the main objectives of the 2030 Agenda for Sustainable Development designed by the Member States of the United Nations. In this work, a hybrid strategy based on process integration is proposed to minimize freshwater consumption while reusing wastewater. As a novelty, the strategy included a heuristic approach for identifying the minimum consumption of freshwater with a preliminary design of the water network, considering the concept of reuse and multiple pollutants. Then, mathematical programming techniques were applied to evaluate the possibilities of regeneration of the source streams through the inclusion of intercept units and establish the optimal design of the network. This strategy was used in the shrimp shell waste process to obtain chitosan, where a minimum freshwater consumption of 277 t/h was identified, with a reuse strategy and an optimal value of US $5.5 million for the design of the water network. [ABSTRACT FROM AUTHOR]

Production of formalin, which is among the highest production volume chemicals, is highly energy-intensive; thus, reduction of energy use is very important in reducing cost and emissions. The aim of this and its larger overall research is to systemically analyze how to improve sustainability of processes producing formalin as an intermediate or final product. In this part of the work, energy consumption requirements are analyzed for the conventional formalin production process via methane steam reforming, where opportunities for energy consumption reduction are identified. This work will serve as a base case for further investigation of alternative formalin production pathways. To achieve energy savings, heat integration technology by combined pinch analysis and mathematical programming is applied. The formalin production process is simulated using Aspen HYSYS, and heat integration of the production process was performed based on simulated design using GAMS software. Economic and environmental footprint analyses were performed for both non-integrated and integrated designs. Results show that heat integration reduces heat consumption by around 39%, leading to a saving of 11% in capital cost and turning annual operating cost into positive revenue. Heat integration also improves the environmental aspect, where a 7–22% reduction in selected environmental footprints is achieved. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Heat pumps are the key technology to decarbonise thermal processes by upgrading industrial surplus heat using renewable electricity. Existing insight-based integration methods refer to the idealised Grand Composite Curve requiring the full exploitation of heat recovery potential but leave the question of how to deal with technical or economic limitations unanswered. In this work, a novel Heat Pump Bridge Analysis (HPBA) is introduced for practically targeting technical and economic heat pump potential by applying Coefficient of Performance curves into the Modified Energy Transfer Diagram (METD). Removing cross-Pinch violations and operating heat exchangers at minimum approach temperatures by combined application of Bridge Analysis increases the heat recovery rate and reduce the temperature lift to be pumped at the same time. The insight-based METD allows the individual matching of heat surpluses and deficits of individual streams with the capabilities and performance of different market-available heat pump concepts. For an illustrative example, the presented modifications based on HPBA increase the economically viable share of the technical heat pump potential from 61% to 79%. [ABSTRACT FROM AUTHOR]

The high freshwater consumption requirements in shrimp biorefinery approaches represents one of the major drawbacks of implementing these technologies within the shrimp processing industry. This also affects the costs associated with the plant operation, and consequently, the overall economic performance of the project. The application of mass integration tools such as water pinch analysis can reduce frewshwater consumption by up to 80%, contributing to shrimp biorefinery sustainability. In this work, the economic evaluation and the techno-economic sensitivity analysis for a mass integrated approach for shrimp biorefinery were performed to determine the economic feasibility of the project when located in the North-Colombia region and to identify the critical techno-economic variables affecting the profitability of the process. The integrated approach designed to process 4113.09 tons of fresh shrimp in Colombia reaches a return on investment (%ROI) at 65.88% and a net present value (NPV) at 10.40 MM USD. The process supports decreases of up to 28% in capacity of production and increases of 12% and 11% in the cost of raw materials and variable operating costs without incurring losses, respectively. These findings suggest that the proposed design of the water recycling network coupled to a shrimp biorefinery approach is attractive from an economic point of view. [ABSTRACT FROM AUTHOR]

Heat exchanger network (HEN) retrofit is a vital task in the process design to improve energy savings. Various types of heat exchangers such as shell and tube, double-pipe, compact plate, and spiral tube have their working temperature ranges and costs. Selecting suitable types of heat exchangers according to their temperature ranges and costs is a crucial aspect of industrial implementation. However, considering the type of heat exchangers in the HEN retrofit process is rarely seen in previous publications. This issue can be solved by the proposed Shifted Retrofit Thermodynamic Grid Diagram with the Shifted Temperature Range of Heat Exchangers (SRTGD-STR). The temperature ranges of six widely used heat exchanger types are coupled in the grid diagram. This diagram enables the visualisation of identifying the potential retrofit plan of HEN with heat-exchanger type selection. The retrofit design aims to minimise utility cost and capital cost. An illustrative example and a case study are presented to show the effectiveness of the method. [ABSTRACT FROM AUTHOR]

The energy and power sectors are critical sectors, especially as energy demands rise every year. Increasing energy demand will lead to an increase in fuel consumption and CO2 emissions. Improving the thermal efficiency of conventional power systems is one way to reduce fuel consumption and carbon emissions. The previous study has developed a new methodology called Trigeneration System Cascade Analysis (TriGenSCA) to optimise the sizing of power, heating, and cooling in a trigeneration system for a Total Site system. However, the method only considered a single period on heating and cooling demands. In industrial applications, there are also batches, apart from continuous plants. The multi-period is added in the analysis to meet the time constraints in batch plants. This paper proposes the development of an optimal trigeneration system based on the Pinch Analysis (PA) methodology by minimizing cooling, heating, and power requirements, taking into account energy variations in the total site energy system. The procedure involves seven steps, which include data extraction, identification of time slices, Problem Table Algorithm, Multiple Utility Problem Table Algorithm, Total Site Problem Table Algorithm, TriGenSCA, and Trigeneration Storage Cascade Table (TriGenSCT). An illustrative case study is constructed by considering the trigeneration Pressurized Water Reactor Nuclear Power Plant (PWR NPP) and four industrial plants in a Total Site system. Based on the case study, the base fuel of the trigeneration PWR NPP requires 14 t of Uranium-235 to an average demand load of 93 GWh/d. The results of trigeneration PWR NPP with and without the integration of the Total Site system is compared and proven that trigeneration PWR NPP with integration is a suitable technology that can save up to 0.2% of the equivalent annual cost and 1.4% of energy compared to trigeneration PWR NPP without integration. [ABSTRACT FROM AUTHOR]

Engines waste a major part of their fuel energy in the jacket water and exhaust gas. Transcritical Rankine cycles are a promising technology to recover the waste heat efficiently. The working fluid selection seems to be a key factor that determines the system performances. However, most of the studies are mainly devoted to compare their thermodynamic performances of various fluids and to decide what kind of properties the best-working fluid shows. In this work, an active working fluid selection instruction is proposed to deal with the temperature match between the bottoming system and cold source. The characters of ideal working fluids are summarized firstly when the temperature match method of a pinch analysis is combined. Various selected fluids are compared in thermodynamic and economic performances to verify the fluid selection instruction. It is found that when the ratio of the average specific heat in the heat transfer zone of exhaust gas to the average specific heat in the heat transfer zone of jacket water becomes higher, the irreversibility loss between the working fluid and cold source is improved. The ethanol shows the highest net power output of 25.52 kW and lowest electricity production cost of $1.97/(kWh) among candidate working fluids. [ABSTRACT FROM AUTHOR]

To date, research on heat pumps (HP) has mainly focused on vapour compression heat pumps (VCHP), transcritical heat pumps (TCHP), absorption heat pumps, and their heat integration with processes. Few studies have considered the Joule cycle heat pump (JCHP), which raises several questions. What are the characteristics and specifics of these different heat pumps? How are they different when they integrate with the processes? For different processes, which heat pump is more appropriate? To address these questions, the performance and integration of different types of heat pumps with various processes have been studied through Pinch Methodology. The results show that different heat pumps have their own optimal application range. The new JCHP is suitable for processes in which the temperature changes of source and sink are both massive. The VCHP is more suitable for the source and sink temperatures, which are near-constant. The TCHP is more suitable for sources with small temperature changes and sinks with large temperature changes. This study develops an approach that provides guidance for the selection of heat pumps by applying Process Integration to various combinations of heat pump types and processes. It is shown that the correct choice of heat pump type for each application is of utmost importance, as the Coefficient of Performance can be improved by up to an order of magnitude. By recovering and upgrading process waste heat, heat pumps can save 15–78% of the hot utility depending on the specific process. [ABSTRACT FROM AUTHOR]

This paper presents the process design and assessment of a sugarcane-based ethanol production system that combines the usage of both mass and heat integration (pinch analysis) strategies to enhance the process efficiency and renewability performance. Three configurations were analyzed: (i) Base case: traditional ethanol production (1G); (ii) mass-integrated (1G2G); and (iii) mass and heat-integrated system (1G2G-HI). The overall assessment of these systems was based on complementary approaches such as mass and mass–heat integration, energy and exergy analysis, exergy-based greenhouse gas (GHG) emissions, and renewability exergy criteria. The performances of the three cases were assessed through five key performance indicators (KIPs) divided into two groups: one is related to process performance, namely, energy efficiency, exergy efficiency, and average unitary exergy cost (AUEC), and the other one is associated to environmental performance i.e., exergy-based CO2-equation emissions and renewability exergy index. Results showed a higher exergy efficiency of 50% and the lowest AUEC of all the systems (1.61 kJ/kJ) for 1G2G-HI. Furthermore, the destroyed exergy in 1G2G-HI was lower by 7% and 9% in comparison to the 1G and 1G2G cases, respectively. Regarding the exergy-based GHG emissions and renewability performance (λindex), the 1G2G-HI case presented the lowest impacts in terms of the CO2-equivalent emissions (94.10 gCO2-eq/MJ products), while λindex was found to be environmentally unfavorable (λ = 0.77). However, λindex became favorable (λ > 1) when the useful exergy of the byproducts was considered. [ABSTRACT FROM AUTHOR]

In the light of the alarming impending energy scene, energy efficiency and exergy efficiency are unmistakably gathering momentum. Among efficient process design methodologies, literature suggests pinch analysis and exergy analysis as two powerful thermodynamic methods, each showing certain drawbacks, however. In this perspective, this article puts forward a methodology that couples pinch and exergy analysis in a way to surpass their individual limitations in the aim of generating optimal operating conditions and topology for industrial processes. Using new optimizing exergy-based criteria, exergy analysis is used not only to assess the exergy but also to guide the potential improvements in industrial processes structure and operating conditions. And while pinch analysis considers only heat integration to satisfy existent needs, the proposed methodology allows including other forms of recoverable exergy and explores new synergy pathways through conversion systems. A simple case study is proposed to demonstrate the applicability and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

The implementation of sustainable water management practices, through the recycling and reuse of water, is essential in terms of minimizing production costs and the environmental impact of the food industry. This problem goes beyond the classical audit and housekeeping practices through developing a systemic water-using reduction strategy. The implementation of such an approach needs R&D development, especially for the food industry, where there is a lack of knowledge on: (a) process integration and (b) data on the pollutant indicators or (c) volumes of water used and discharged at specific steps of the food processing line. Since energy pinch analysis emerged, different variations of pinch methods have been developed. As a variation of pinch, Water pinch analysis is a global and systematic approach to minimize water consumption and discharges, especially for the most energy-intensive and water-consuming factories. Based on the nature of the food industry, the real systems are complex, multi-source multi-contaminant systems, the problem should be well formulated, including mathematical constraints (inequalities thresholds). Current work has reviewed comprehensive literature about different variations of pinch analysis. In continue, water pinch method deeply discussed and some relevant data concerning the water using process and pollutant indicators have been reviewed with emphasis on the food industry sector. [ABSTRACT FROM AUTHOR]

Research and development on integrated energy systems such as cogeneration and trigeneration to improve the efficiency of thermal energy as well as fuel utilisation have been a key focus of attention by researchers. Total Site Utility Integration is an established methodology for the synergy and integration of utility recovery among multiple processes. However, Total Site Cooling, Heating and Power (TSCHP) integration methods involving trigeneration systems for industrial plants have been much less emphasised. This paper proposes a novel methodology for developing an insight-based numerical Pinch Analysis technique to simultaneously target the minimum cooling, heating and power requirements for a total site energy system. It enables the design of an integrated centralised trigeneration system involving several industrial sites generating the same utilities. The new method is called the Trigeneration System Cascade Analysis (TriGenSCA). The procedure for TriGenSCA involves data extraction, constructions of a Problem Table Algorithm (PTA), Multiple Utility Problem Table Algorithm (MU PTA), Total Site Problem Table Algorithm (TS PTA) and estimation of energy sources by a trigeneration system followed by construction of TriGenSCA, Trigeneration Storage Cascade Table (TriGenSCT) and construction of a Total Site Utility Distribution (TSUD) Table. The TriGenSCA tool is vital for users to determine the optimal size of utilities for generating power, heating and cooling in a trigeneration power plant. Based on the case study, the base fuel source for power, heating and cooling is nuclear energy with a demand load of 72 GWh/d supplied by 10.8 t of Uranium-235. Comparison between conventional PWR producing power, heating and cooling seperately, and trigeneration PWR system with and without integration have been made. The results prove that PWR as a trigeneration system is the most cost-effective, enabling 28% and 17% energy savings as compared to conventional PWR producing power, heating and cooling separately. [ABSTRACT FROM AUTHOR]

The design of heat exchanger networks (HEN) in the process industry has largely focused on minimisation of operating and capital costs using techniques such as pinch analysis or mathematical modelling. Aspects of operability and flexibility, including issues of disturbances affecting downstream processes during the operation of highly integrated HEN, still need development. This work presents a methodology to manage temperature disturbances in a HEN design to achieve maximum heat recovery, considering the impact of supply temperature fluctuations on utility consumption, heat exchanger sizing, bypass placement and economic performance. Key observations have been made and new heuristics are proposed to guide heat exchanger sizing to consider disturbances and bypass placement for cases above and below the HEN pinch point. Application of the methodology on two case studies shows that the impact of supply temperature fluctuations on downstream heat exchangers can be reduced through instant propagation of the disturbances to heaters or coolers. Where possible, the disturbances have been capitalised upon for additional heat recovery using the pinch analysis plus-minus principle as a guide. Results of the case study show that the HEN with maximum HE area yields economic savings of up to 15% per year relative to the HEN with a nominal HE area. [ABSTRACT FROM AUTHOR]