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This study aims to analyze the effect of PSA off gas utilization on fuel processing system combined with PSA (Pressure Swing Adsorption) system to produce more than 99% hydrogen for LT-PEMFC (Low Temperature Proton Exchange Membrane Fuel Cell) supply. An analysis was performed to optimize the operating conditions of a fuel processing system coupled with a PSA system by utilizing PSA off-gas to supply hydrogen to a 10 kW LT-PEMFC system. The performance and efficiency of the entire system were investigated at a steam-methane reactor temperature of 600 °C–800 °C, a water gas conversion reactor temperature of 200 °C–400 °C, a PSA recovery ratio of 60%–95%, a pressure of 1 bar, and 9 bar using Aspen Plus®, Aspen adsorption®, and Aspen Energy Analyzer® simulators. The sensitivities of various parameters affecting the process were analyzed to obtain optimized conditions for the entire system. Simulation results show that the optimal reformer temperature depends on the PSA recovery. The overall maximum efficiency is 78.67% at a process pressure of 9 bar the PSA recovery ratio of 95% and a temperature of 800 °C. In contrast, the highest efficiency under the 1 bar process condition is 70.55%, with an operating temperature of 600 °C and PSA recovery of 95%, which is relatively lower than the 9 bar process. Subsequently, pinch analysis and economic analysis including exergy analysis according to PSA recovery were conducted on these processes, showing that the thermal efficiency of the 9 bar process is relatively higher. The economic analysis indicated that the optimal profit is achieved at a PSA recovery of approximately 70∼75% and more than 40.2% of energy can be saved by utilizing PSA off gas to supply reaction heat for methane-steam reforming. • Process simulation for combined system of SMR and PSA •Utilization of PSA off gas to increase the system efficiency •The optimal reformer temperature depends on the PSA recovery ratio •Overall efficiency is improved by up to 78% compared to the conventional process •Pinch analysis and economic analysis including exergy analysis [ABSTRACT FROM AUTHOR]

The synergies from integrating direct air capture and CO2 methanation are assessed and quantified. Three direct air capture and methanation processes with different integration strategies are proposed: only heat integration, direct air capture sorbent regeneration with high‐pressure H2, and complete integration in a single unit. The heat integration study via pinch analysis evaluated the potential energy demand reduction. Overall autothermal operation is achievable, as the heat generated in methanation often exceeds that required for direct air capture sorbent regeneration. A novel process combining CO2 adsorption and methanation in one reactor provided the best productivity and energy demand results. However, this design requires complex cycles and strict demands on the sorbent and catalyst, requiring further development and experimental demonstration. [ABSTRACT FROM AUTHOR]

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]

Green ammonia and hydrogen from renewable energy sources have emerged as crucial players during the transition of the chemical industry from a fossil energy‐dominated economy to one that is environmentally friendly. This work proposes a green ammonia synthesis system driven by synergistic hydrogen generation using alkaline water electrolyzers (AWE) and proton exchange membrane electrolyzers (PEMEC). The effects of hydrogen‐production ratios of PEMEC and AWE on the thermodynamic and economic performance of the system are compared and analyzed via multi‐objective optimization. The findings showed that an increase in the amount of hydrogen produced by PEMEC improves the system's energy efficiency, but the payback period is delayed because of the PEMEC high initial investment cost. The techno‐economic performance of the system at a 1:1 ratio of PEMEC to AWE hydrogen production are investigated considering the system level heat integration based on the pinch point analysis method to maximize the heat recovery. The results show that increasing the operational temperature, the pressure of the electrolyzer, and the ammonia synthesis pressure will enhance the system's thermal performance. Economic analysis shows that reducing electricity prices and electrolyzer investment costs will be the key to achieving the economic feasibility of the green ammonia system. [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]

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.

Objective: the objective of this study is to conceptualize a network of heat exchangers designed to minimize energy waste and enhance the overall efficiency of the sugar production system. Methods: a systematic approach was adopted to analyze energy flows within the plant, identifying key areas for improvement, particularly in heating and evaporation processes. Heat accumulations in cascades and graphical analyses of composite curves were developed using specialized software to optimize heat exchange. Results: the results indicate a significant potential for energy savings, reducing the consumption of cooling and heating utilities in the plant by 7% and 30%, respectively. The developed computational tool allows for energy integration from simple processes to those with hundreds of streams. The pinch technology concept estimated an annual total savings of $464,850.08 in the selected process. Conclusion: this study demonstrates that thermal integration through pinch analysis not only improves energy efficiency in the sugar industry but also contributes to a considerable reduction in operational costs and environmental impact, providing a valuable tool for the industry's sustainability and competitiveness. [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]

This study employs pinch analysis to optimize the performance of multi-stage micro heat exchangers (MHEs) in industrial applications. The research pinpoints crucial pinch points that optimize heat transfer potential and employs advanced computational fluid dynamics (CFD) simulations to forecast flow patterns and temperature profiles. The analysis emphasizes comprehensive design considerations and provides actionable guidelines to enhance the performance and sustainability of MHEs across various industrial applications. Key findings include that tubes with a 2 mm diameter exhibit higher heat exchange efficiency compared to those with a 3 mm diameter, and the optimal pipe spacing for heat exchange efficiency is 7.5 mm. These results are validated through HYSYS-generated pinch analysis charts, revealing economic benefits for specific tube diameters and spacing's. The strain contrast improved for the 5 mm pipe separating line. The pipe diameter of 2 mm showed lower convergence between hot and cold composite curves, suggesting economic benefits for 2 mm heat exchangers. The pinch point hot and cold temperatures were 54.65, 41.58, and 35.46 degrees Celsius, respectively. [ABSTRACT FROM AUTHOR]

In this article, we extend a previously developed globally optimal enumeration methodology for the synthesis of heat exchanger networks (HENs) to include the basic design of heat exchangers (HEXs). The method addresses together all trade‐offs between network structure, energy usage, and the basic design of the HEXs. Without loss of generality, we focus on shell‐and‐tube HEXs. Unlike previous approaches, such as Pinch Analysis, Metaheuristic methods, or Mathematical Programming, our procedure guarantees global optimality. The procedure is not iterative and does not present any convergence challenges. We enumerate HEN structures using a mixed‐integer linear programming method and we use Set Trimming followed by sorting for the HEX design. In addition, because some network structures are incompatible with single shell exchangers, we use multiple shell exchangers in series. The comparison of the results of the proposed approach with solutions obtained using two alternative methods extracted from the literature indicates that considerable cost reductions may be obtained. [ABSTRACT FROM AUTHOR]

Government allocated funds earmarked toward the improvement of recreational amenities like parks and playgrounds in developing nations are usually scarce, leading to their disrepair and encroachment. Provision of amenities and vegetation development are vital features of open spaces and the associated costs form a major share of the budget allocations. With the limited resources available for open spaces' development, it is crucial to utilize the said funds judiciously. This paper investigates the cost implications of providing amenities and vegetation in urban Indian open spaces and devices a framework to improve the open space performance score cost-effectively. The associated fund utilization is optimized for select open spaces using the graphical representation of pinch analysis. Four scenarios of development namely greenfield, brownfield, vegetation-focused development and amenities-focused development are tested for four open spaces of diverse sizes and performance scores. The inefficiency associated with fund utilization is highlighted using the pinch diagram. Furthermore, in most cases, it is observed that the provision of amenities prior to vegetation development provides swifter increase in ROS performance. The study demonstrates a novel method to evaluate the cost implications of open space development for decision-makers and suggests pertinent policy recommendations [ABSTRACT FROM AUTHOR]

Copyright of Studia Ecologiae et Bioethicae is the property of Uniwerystet Kardynala Stefana Wyznskiege w Warzawie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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 the industrial sector, efficient production and optimal use of thermal energy are primary concerns for managers and engineers. Considerable research has been devoted to improving and promoting thermal energy efficiency, especially energy recovery in the context of sustainability. Pinch analysis is one of the most powerful methods in this regard. To maximise the energy recovery (MER), the pinch method is well-established in designing an optimal heat exchange network (HEN). Exergy analysis is combined with the pinch method to minimise the work potential loss (exergy loss) while ensuring maximum heat recovery. This study presents a generic algorithm built using Python language to predict and quantify energy and exergy targets in industrial processes. It provides a framework to guide experts and planners in efficiently using the combined analysis tools. The generic algorithm is based on advanced numerical and graphical tools. It provides exergy problem table algorithm (Ex–PTA) and grand composite curve (EHR and HRP) tools. For Δ T min = 10°C, the generic algorithm is implemented in a building complex case study. The energy targets for heating and cooling requirements are 316.2625 kW and 0 kW, respectively. The obtained exergy targets are less attractive given an improvement from advanced utility integration; this is due to the treated system (medium-temperature system) and not to the reliability and efficiency of the generic algorithm. To evaluate the generic algorithm calculations, they are executed in a low-temperature process in which pinch exergy analysis (PExA) has already been performed. The simulated and generated results are identical, demonstrating the reliability and effectiveness of the developed generic algorithm. [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the external and internal compatibility of the Biometrics E-LINK EP9 evaluation system device in the area of hand grip and pinch strength in the Polish population. The testing of hand grip and pinch strength was carried out among 122 healthy students. Two examiners performed hand grip and pinch strength measurements with a Biometrics E-LINK EP9 evaluation system device. Measurements were made for the right and left hands. The same people were tested again two weeks later, under the same conditions. The scores of one rater on the first and second tests were compared for reproducibility, and the scores of the two raters were compared to assess the reliability of the instrument. The measurements were found to be highly consistent both between the investigators and between the tests in the hand grip dynamometer test. The findings show high values of the Pearson's correlation coefficient equal or close to 1, as well as the interclass correlation coefficient (ICC) >0.9. Analysis of pinch strength measurements performed using the pinchmeter also found high values of the Pearson's correlation coefficient close to 1, as well as the interclass correlation coefficient >0.9; this reflects high agreement between the measurements performed by two investigators as well as assessments performed by one investigator at time intervals. These findings were confirmed by analyses performed using Bland-Altman plots. The measurements made with the Biometrics E-link EP9 evaluation system show high internal and external consistency in hand grip and pinch strength assessment. Biometrics E-link EP9 can be recommended for daily clinical practice. [ABSTRACT FROM AUTHOR]

The water-, and energy footprints of the processes in the pulp and paper industry are sizable enough to warrant investment of money and commitment of time truncate the same. Besides, there is also a nexus between water and energy here, with optimisation of the use of one of these resoruces enabling that of the other too. This streamlined review focuses on journal publications (originating from different parts of the world, and targeted at researchers and decision-makers in the industry) which train the lens on the optimisation of water use in this particular sector of the (forestry) bioeconomy. The synergies and complementarities which exist among different sustainable development goals (SDGs) , promise positive ripple effects, caused by attending to the truncation of the water footprint. The articles, in general, recommend effective in-plant wastewater treatment in combinaton with recirculating the treated effluent, and looking upon the water streams as carriers or bearers of valorisable substances – organics which can yield a host of bio-products in bio-refineries, including bio-energy. Availing of water-pinch analysis as a tool to uncover possibilities of water use in a cascade (depending upon the requirements imposed on the water, by processes downstream in the cascade), has been shown to aid in the optimisation of both water use and energy demand within the plant. One case study, for example, showed that the demand for steam can be decreased by about 4 GJ per ton of output, by recovering the waste heat in the water streams.

This study aimed to enhance the thermal efficiency of the sulphitation process in the boiling house of sugar plants using a combined approach of pinch and exergy analyses. Pinch analysis is a reliable method for optimizing the design of energy recovery systems. However, the primary limitations arise from its exclusive focus on heat transfer processes. On the other hand, exergy balance provides valuable insight into the consumption of supplied exergy by individual process units, serving as a quantitative measure of inefficiency. The boiling house was evaluated and modified using pinch-exergy analysis with Sulphitation Process capacity production of 8000 TCD. The results showed a potential reduction in exergy destruction by approximately 10.25 MW. The optimization effort led to reductions of 18.18 and 14.70% in the use of hot and cold external utility, respectively.

The chemical industry is acquiring new advancement day by day. Previously, quite massive equipment had been used to do heat transferring tasks, but now the industry has been modernised. Heat Integration is a trending area of study that might be applied in several sectors to redesign processes. Heat Integration alludes to any technique in chemical engineering that results in considerably smaller, greener, and more energy-efficient appliances. Heat Integration aims to improve energy transfer, lowering the equipment's capacity for heat transfer. This paper uses pinch analysis to optimize heat integration and find the best heat-exchange network through case studies. Pinch Technology offers a systematic approach to reducing energy use across all sites and activities. It is feasible to determine the proper alterations to the fundamental process parameters that can result in energy savings by using pinch technology. The Aspen Energy Analyzer tool has been used to compute the heat integration of the case studies. After obtaining the data from the software, they were used in pinch analysis to determine the optimal alternative for the heat exchanger network. [ABSTRACT FROM AUTHOR]

The thermal energy transfer characteristics of heat exchangers with thermal fins and evaluates their economic feasibility. It uses computational fluid dynamics simulations and economic analyses to examine various fin geometries, materials, and configurations. The results reveal that fin design parameters, such as height, thickness, spacing, and material properties, significantly influence heat transfer efficiency. The study emphasizes the importance of optimizing these parameters to balance thermal performance and costeffectiveness. The findings guide engineers and policymakers in selecting and optimizing thermal fins. A range of water flow speeds of 0.1, 0.5, and 1 m/s was used, and the dimensions of the fins were reduced in a manner commensurate with the nature of thermal energy transfer and to reduce the manufacturing cost. The study shows that thermal energy transfer through fins increases with fluid flow speed, with the pipe's exit temperature reaching 88 degrees Celsius at 0.1 m/s and 96 degrees Celsius at 0.5 m/s. The fins' temperature distribution varies, reaching 88 degrees Celsius, 94 degrees Celsius due to fin length changes, and 91 degrees Celsius despite fin size changes. The study also analyzed energy transfer through different shapes and flow speeds, finding that shape 1 transferred 340 W at 1 m/s, shape 2 decreased to 144 W, and shape 3 increased surface area but not volume. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Industry / Hemijska Industrija is the property of Association of Chemical Engineers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Balancing burgeoning energy demands in the electricity sector while curbing carbon emissions poses a formidable challenge for emerging economies like Bangladesh, which is heavily reliant on fossil fuels. Despite the country's power system master plan (PSMP) until 2041 and submitted intended nationally determined contributions (INDC) to tackle mounting energy needs and associated emissions, the PSMP lacks specific emission reduction strategies. Thus, this study employs carbon emission pinch analysis to facilitate Bangladesh's long-term energy planning, highlighting emission reduction hurdles. This research aims to set emission limits, delineate fossil fuel and carbon-neutral source (i.e., zero emission during operation) compositions, ascertain carbon-neutral source ranges for targeted emissions, and propose viable carbon-neutral sources to meet escalating energy demands. Three scenarios are extensively explored: fulfilling INDC mandates, a 10% increase in renewable energy, and maintaining 2035 emission levels in 2040. The analysis unveils emission limits of 55 758.83 and 84 778.61 × 109 grams of CO2 equivalent for 2025 and 2030, respectively. Projections indicate a foreseen 10% surge in renewable energy by 2035, elevating its share to 18.16%. Carbon-neutral energy sources, encompassing solar, wind, hydroelectricity, biomass, and nuclear, are estimated to cover 56.06% of energy demand by 2040, driving a 33.30% emissions reduction. [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]

The number of data centres (DC) in recent years is growing rapidly, and with that, the share in total consumption of electricity is growing too. A significant amount of electricity is transformed into heat energy which increases the optimal temperature in DC for component operation. This heat needs to be removed and usually, it doesn't have any further application. Today it is recognized that waste heat can be integrated into district heating (DH) and by using it reduce the usage of conventional heat fuels. Integration of waste heat is possible in three ways: with a heat exchanger (HEX), with a booster heat pump, or with the combination of the HEX and heat pump. In this paper, a combination of HP and HEX was used. Although those utilizations are examined and implemented, there is a lack of research on the optimization of the integration of waste heat into the district heating network (DHN). To perform optimization, a thermodynamic model of the DC and a pinch analysis model were developed. In this study, a method for evaluating the economic feasibility of DC waste heat integration into DH systems is proposed. The most suitable integration technology of waste heat into DH systems by using the hourly merit order of waste heat utilization technologies based on pinch analysis is found. The connection pipe between DC and DHN is optimized, and the ideal diameter is determined considering different temperature regimes of the network: low-temperature, ultralow temperature, and neutral temperature networks. The methodology was tested using a case study of a DC in the City of Zagreb. [ABSTRACT FROM AUTHOR]

The reversible operation of a commercialized molten carbonate fuel cell as an electrolyzer is attractive to store the surplus of renewable energy and convert CO 2 into valuable fuel, like syngas (H 2 and CO). This work aims to assess this capability by developing a model for the co-electrolysis of CO 2 and H 2 O in the molten carbonate electrolysis cell (MCEC). Furthermore, a 1 MW power-to-gas system is simulated and optimized to maximize the process efficiency via a profound sensitivity analysis and a pinch heat integration analysis. The study's results reveal that when CO 2 electrolysis occurs, there is a risk of reaching the limiting current density at lower values, thus affecting the cell's performance. As for the simulation, the process yields an efficiency of 68.87% with an electrolyzer's power density of 0.082 W/cm2 per cell, producing 1.3 tons/day of methane gas ready for injection into the natural gas network. • Co-electrolysis of H 2 O and CO 2 in a molten carbonate electrolyzer was modelled. • 1 MW power-to-gas system is simulated and optimized via a sensitivity analysis. • Process yields an efficiency of 68.87% with 1.3 tons/day methane gas production. • The electrolyzer operates at a power density of 0.082 W/cm2 per cell. [ABSTRACT FROM AUTHOR]

The development of the conceptual design of a technology for obtaining concentrated nitric acid at 99 % by weight from conventional nitric acid is presented through the analysis of 2 production alternatives, using a process simulator. For the conceptual design, process analysis techniques such as mathematical modeling, process simulation, optimization, economic analysis and Pinch analysis were used, among others. The process flow diagrams of both alternatives are also presented, as well as the validation of the mathematical model used to calculate the vapor - liquid balance in the water - nitric acid-magnesium nitrate system, as well as the sizing of the main equipment, optimizing the 2 feed and solvent inlet plates, as well as the heat transfer area of the heat exchange equipment. Finally, a summary of the economic analysis carried out for the two alternatives studied and the selection of the best one is presented. [ABSTRACT FROM AUTHOR]

In order to response to the “double carbon” strategy for reducing emissions, chemical production processes were optimized to lower the amount of utility work and equipment investment expenses with increasing the system’s capacity for heat recovery. A sensitivity analysis and the energy efficiency analysis with pinch technique were performed on the distillation and purification of the 30 kt/a isopropyl acetate (IPAC) production process by using process simulation software of Aspen Plus. The IPAC refining tower optimization results show that the purity of the refined IPAC could be reached 99.9% at circumstances of 44 theoretical plates, 19 feed plates, and 0.755 reflux ratio. According to the optimized energy consumption data from Aspen Energy Analyzer (AEA), the cold and heat logistics matching was performed. It can be seen that the heat exchange network was tuned to maximize energy recovery by reducing the amount of utility work. The optimized cold and heat utility usage were 734.69 and 727.81 kW, which meaning that compared with original process, the cold and heat utility usage energy can be save with 10.0%, respectively. The optimized results provide a certain theoretical basis and solution for improving energy saving and reducing investment costs. [ABSTRACT FROM AUTHOR]

Hydrogen has been considered a future energy carrier for decades and the demand for hydrogen in refineries is always upward due to the revival of new technologies. The steam methane reforming method is frequently employed because of its high hydrogen generation efficiency at a cheap cost and minimal environmental footprint. However, depending on the type of feedstock, one unit of hydrogen generates 9e10 units of CO2 that need to be treated for environmental sustainability. Therefore, the optimization of hydrogen production and CO2 capture is critical to address the issue. The simulation research was conducted to anticipate and optimize steam reforming using Aspen HYSYS. A conversion-type reactor was used to develop this simulation-based model. The primary goal of this work is to investigate and optimize hydrogen production efficiency while mitigating CO2 by varying process parameters. The CO2 capture efficiency was investigated at the different yields for hydrogen production and a maximum of 98.8 % absorption of the CO2 was achieved using the carbon capture system proposed in the current study. Later, the Aspen Energy Analyzer tool revealed potential improvements for energy and cost optimization. [ABSTRACT FROM AUTHOR]

Spray drying systems with heat recovery have gained prominence in recent times due to the energy crises and changing weather conditions. These systems are widely used in various industries, including chemical, food, fertilizer, and pharmaceutical, but their energy-intensive nature calls for efficient operation and heat retrieval. This review article discusses the current developments in heat recovery methods, including direct, indirect, and hybrid systems, as well as improvements in dryer efficiency and thermal optimization techniques. Pinch and exergy evaluations are extensively investigated as they play a crucial role in heat integration design and analysis. Recovering heat from the exhaust stream of spray dryers poses challenges due to fouling caused by fines in the exit stream and the selection of analysis methods. Exploring non-conventional energy sources like solar and geothermal energy shows potential for drying operations, but further research is needed for design and control. The adoption of recovery options has led to a 35% improvement in energy efficiency and around 74% energy savings in specific cases. [ABSTRACT FROM AUTHOR]

Trinidad and Tobago's (T&T) conditional commitment to the Paris Agreement requires an overall power emission avoidance (EAT) of 28.7 MtCO2-e from Business-As-Usual by 2030, dependent on international financing. T&T has outlined several initiatives to achieve this, including zero-carbon renewable energy (RE) introduction. However, other technologies such as Carbon Capture and Storage (CCS) can also be used in support of achieving EAT. Using a specific scenario (S3), this study assesses the techno-economics of CCS within the sector to minimize the requirement of RE using a carbon measuring tool called Carbon Emission Pinch Analysis (CEPA) to achieve EAT. Local power plants were screened, and a CCS retrofit was then technically designed using a validated software called Aspen HYSYS. Multi-period CEPA methodology was then applied to quantify ∼17% of grid energy from RE along with CCS to achieve EAT. Economic models were also used to determine the grid unit cost of emission abatement for S3 to be 64 USD/tCO2-e; a doubling of initial projection requirements. With T&T's current dynamics, these findings can help guide actions to reduce the requirements of RE onto the grid through the supplemental introduction of CCS to achieve its EAT. [ABSTRACT FROM AUTHOR]

• Energetic and exergetic analysis of a TC-HTHP cycle configurations. • Gas-cooler pinch point analysis of a TC-HTHP cycle. • Environmental impact of operating a TC-HTHP within an industrial process. • HC-600 (Butane) demonstrated the highest VHC values and, therefore, the smallest size of compressor. Sub-critical mechanically driven industrial heat pump technologies have gained momentum in recent years with systems capable of supplying temperatures up to 150°C. Extending the operating envelope using heat pump technologies to and beyond 200°C requires an innovative shift towards transcritical techniques to meet the demands of a broader range of industrial processes. Transcritical high-temperature heat pumps (TC-HTHPs) pose many technical and operational challenges requiring research and development to evaluate operational performance. This paper assesses the feasibility of operating a HTHP system to achieve 200°C heat sink temperatures using suitable low GWP refrigerants. The work investigates three different TC-HTHP cycle configurations using a steady-state theoretical model to compare and evaluate energetic, exergetic and environmental performance. In addition, cycle performances for this study are obtained at the optimum pressure for the gas cooler in which the maximum COPs are achieved. The results reveal that the basic cycle with dual internal heat exchanger (IHX) was the most efficient configuration, with HFO-514A and HFO-1234ze(Z) refrigerants identified as the most promising candidates for TC-HTHP systems. Configurations employing HCFO-1233zd(E) exhibited a trade-off between high energetic and exergetic efficiency while providing an A1 safety group classification. A pinch point analysis of the gas cooler demonstrated the need to optimise the overall length to achieve increased operational performance at very high glide temperatures. An evaluation of the environmental impact identified reductions in TEWI value by up to 20 % for the refrigerants tested over HFC-245fa. This study provides a basis for future practical activities of TC-HTHPs using eco-friendly candidates. [ABSTRACT FROM AUTHOR]

Energy efficiency and process integration play a vital role in minimizing fossil fuel consumption and electricity demand within industrial processes. Therefore, experts have prioritized research on enhancing and promoting the thermal energy efficiency of this sector, with a specific emphasis on energy recovery and sustainability goals. Pinch analysis (PA) and exergy analysis (ExA) have been employed separately or in conjunction to optimize energy recovery and minimize the work potential losses (exergy loss). This paper demonstrates the effectiveness of a developed algorithm that handle the impact of ΔTmin on energy and exergy targets in an automatic manner through a set of scripts. The scripts manipulate input data and intermediate data through loops in order to quantify and determine different energetic and exergetic quantities. The developed algorithm is testified using a literature case study in order to prove its validity. For δTmin in range [0,10] and step s = 2, the algorithm performs the calculations for each δTmin in range ΔTmin. The obtained results include the pinch analysis parameters such as the global pinch point temperature [Tpinch] as well as the minimum heating and cooling requirements ([Uhot] and [Ucool]). For the scripts devoted to the exergy concept, the algorithm determines all the exergy targets (rejection, requirement and avoidable losses). As a result for δTmin in ΔTmin, the process external utilities Uhot and Ucool increased simultaneously from 6.85 and 4.39 MW to 12.2 and 9.75 MW with increment of δTmin, which means that the energy recovery and avoidable exergy losses reduced with respect to δTmin. For the exergy requirement and rejection targets, they increased simultaneously from 2.6602 and 1.3231 MW to 6.711 and 2.88 MW with δTmin increment, indicating the opportunity to design a system to recover work through turbine expansion. In addition to the originality of the interconnected scripts, the obtained results are in accordance with those in the literature, indicating the applicability of the developed algorithm. [ABSTRACT FROM AUTHOR]

The actual task of the state is to increase the energy efficiency of the oil refinery. The object of research is a vacuum distillation unit, including a preheating unit for raw materials and a furnace for heating fuel oil before the column. Pinch analysis allows to analyze and optimize a large number of heat flows. In this study the analysis and enhancement of efficiency of the research object is carried out by enthalpy pinch analysis. In order to reduce the heat load of the furnaces, the additional flows were introduced into the heat exchange system of the oil heating unit. Parametric optimization of the new heat exchange system was carried out. The minimum needs of the heat exchange system in external energy carriers are determined. An enthalpy cascade of the heat exchange system has been constructed, which clearly shows the distribution of heat between each heat flow of the system. In the analysis of the energy efficiency of a furnace, an important point is the determination of the optimal heat capacity of the combustion products. In this work, we have determined the optimal flow heat capacity, at which the heat loss with the exhaust gases is minimal. As a result of the studies carried out, the efficiency of the fuel oil preheating unit has been increased by maximizing heat recovery, and the cost of external energy carriers has been minimized. By reducing heat loss with flue gases, it was possible to increase the efficiency of the furnace.

While various methods of direct air capture (DAC) technology have been implemented, its widespread effectiveness hinges on achieving optimal design and process improvements, largely owing to the high energy costs involved. Literatures reports a substantial heat demand for high-temperature aqueous solutions DAC (HT DAC), ranging from 1420 to 2250 kWh per ton of CO2, accompanied by electricity consumption rates varying from 366 to 2790 kWh per ton of CO2. The present study adopts the HT DAC method with an aqueous KOH absorbent as its focus, aiming to mitigate energy consumption. Given that a substantial portion of energy consumption in comparable processes can be attributed to the calciner and slaker units, our research centers its attention on the Air Separation Unit (ASU) and the steam cycle unit, investigating their impact on the system's production capacity, the enhancement of CO2 purity, and the augmentation of equipment thermal recovery. Process optimization, results a remarkable increase in heat recovery (21.1 %) and significant reductions in utilities consumption. The outcomes indicate that this facility has the capacity to annually capture around 1.1 million tons of CO2 with a purity of 99 mol% for utilization across various industries. The process design necessitates 5.24 gigajoules (GJ) of heat and 343 kW-hours (kWh) of electricity per ton of captured CO2. Notably, in addition to fulfilling the internal electricity requirements, the facility can export 8 MWh of electricity per ton of captured CO2 to the grid.

Energy cost represents a significant part of the total operating costs of many processing units. Crude distillation is an energy intensive process. Energy integration is a typical solution to reduce heating and cooling utilities through maximizing the target temperature of crude oil streams before entering the furnace. Over the past few decades, significant progress has been made in energy integration methods including pinch technology and mathematical programming approaches. Very recently, graphical techniques have been developed for revamping studies and energy analysis. Such diagrams are valuable in energy targeting to identity energy inefficiencies and are key to potential modifications for maximum energy integration. The current research applies the recent graphical revamping methodology on an existing crude atmospheric distillation unit. The unit is located in north of Egypt (Suez region) and is operated under two different operational modes; (1) without naphtha stabilizer; the process reformer is in operation to reform all naphtha streams without stabilization and (2) with naphtha stabilizer; LPG is separated from naphtha stream. A graphical-based revamping methodology is applied to retrofit the existing preheat train. The revamping procedure starts by simulating the existing HEN data, followed by validation against the real data. The current performance of the HEN is analyzed using the graphical axes of Thot-Tcold diagrams. The graphical method is then used to identify exchangers across the pinch and recognize the potential modifications to improve the energy performance and reduce fuel consumption. Implementing the graphical identified modifications on the plant resulted in the following benefits: (1) when stabilizer is in operation, energy savings are achieved by 21.1% with additional capital investment of 0.81 MM$ and annual energy savings of 0.82 MM$, with a payback period of one year. (2) when reformer is in operation, the energy savings are 0.42 MM$ with capital investment of 0.33 MM$. The methodology results provide a flexibility in refineries operations.

The effective utilization and conservation of energy are crucial challenges in industrial process systems. The chemical engineering industry is actively researching the integration of processes via heat exchanger networks synthesis. The strategy presented in this work utilizes recent advancements in pinch technology to investigate the impact of minimum approach temperature variation on energy and capital costs. The multi-objective problem considered in this approach involves minimizing utilities of heating and cooling, minimizing the area of heat exchanger, minimizing irreversibility, and maximizing effectiveness. The technique of order preferences by similarity to an ideal solution (TOPSIS) is applied to determine the optimal heat exchanger network based on the compromise solution concept, which is achieved by selecting the network having the closest Euclidean distance to the perfect solution. The practicality of this methodology is validated by resolving two distinct cases, the first case involve ten streams, the second industrial case is a separating crude oil into its primary constituents namely naphtha, kerosene, diesel and residue which demonstrate that this technique can provide more practical solutions compared to prior literature. Additionally, the study reveals that the novel approach can identify other multi criteria decision making problems with a discrete number of alternatives, criteria and are more cost-effective networks than those produced by alternative techniques. [ABSTRACT FROM AUTHOR]