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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]

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]

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]

The development of technologies for utilizing biomass has attracted attention because biomass can be produced sustainably worldwide. Biomass‐derived 2‐methyltetrahydrofuran (MTHF), which is a promising alternative to gasoline, has great market potential and a growing demand. However, in conventional biomass conversion processes, the minimum selling price (MSP) of biochemicals is not economically acceptable. Co‐production of biochemicals can increase the economics of biomass utilization. Herein, we developed a process for co‐producing MTHF and 1,4‐pentanediol (1,4‐PDO) from lignocellulosic biomass. After biomass fractionation, cellulose and hemicellulose were converted to levulinic acid (LA), and lignin was used for heat and electricity generation. LA was then converted to γ‐valerolactone (GVL). As a platform material for co‐production, GVL was converted into MTHF and 1,4‐PDO in each subsystem. The split ratio of GVL was controlled to efficiently produce MTHF and 1,4‐PDO according to market conditions. Additionally, we performed a techno‐economic and life‐cycle assessment (TEA and LCA, respectively) for the developed process. The MSP of MTHF was calculated based on the TEA results, and the environmental impacts were quantitatively calculated based on the LCA results. We performed heat integration using pinch analysis and then reduced the energy requirement of the proposed process. The key cost drivers and environmental factors of the proposed process were identified via sensitivity analyses. Consequently, during the processing of 2000 ton/day of corn stover (raw material of lignocellulose), the MSP of MTHF was calculated as $2.64/GGE (gasoline equivalent), and representative environmental impacts such as climate change and fossil depletion were calculated as −0.296 kg CO2 eq and − 0.056 kg oil eq, respectively. As a result, we can increase the economics of commercial production of MTHF and 1,4‐PDO with environmental sustainability. The proposed process can serve as a potential solution to the growing demand for the need for more sustainable biomass utilization. [ABSTRACT FROM AUTHOR]

A generalized MATLAB scheme is developed to analyze and design heat exchanger networks (HENs) in process industries. This scheme has been checked for various industrial problems from the literature. The results produced by the proposed scheme are in exact agreement with the literature. The proposed scheme is user‐friendly and less time‐consuming. It will be helpful for industry persons, process engineers, and budding chemical engineers, involved in modeling and simulation studies in order to minimize the energy requirements of industries as well as for academic purposes. The proposed scheme just needs a MATLAB package which is easily available and cheaper than other commercially available heat exchanger network design packages. [ABSTRACT FROM AUTHOR]

Nowadays, energy storage system is utilized in many countries for energy planning in the future. The changes in solar radiation lead to the overproduction of electricity in a solar photovoltaic generator. A hybrid energy storage system would play an important role in enhancing the reliability of power generation using the solar system. The microgrid is the indispensable infrastructure of the smart grid in photovoltaic systems. In this paper, the energy storage system within the microgrid of the PV system is analysed. The storage system configuration and topologies of the microgrid are analysed with power electronic interference, control scheme, and optimization of the renewable source and energy storage system. A general sizing technique for HESS in a PV system based on pinch analysis and design space. The size of HESS scales that connect generator ratings to storage capacity is created by utilizing the pinch analysis on load and resource data. The design space is a feasible combination of a short-, long-, and medium-sized energy storage system in a PV generator. [ABSTRACT FROM AUTHOR]

A new graphical method for the fundamental design of pressure‐swing distillation (PSD) and valid heat integration of the designed process is demonstrated based on a pinch analysis. As the minimum pressure constraint, the pinch pressure is determined by this graphical method to secure the necessary temperature driving force and circumvent the distillation boundaries. For a feasibility evaluation of heat‐integrated PSD (HIPSD), the suggested approach requires visualization of the pinch temperature contours and the feasible composition region of an initial feed according to the pressure change and dynamic properties of ternary azeotropic systems. We thus carried out an in‐depth examination by conducting case studies to show the feasible integration into HIPSD. The new insight is that the HIPSD system can have different pinch pressures depending on the column sequence or the separation order of pure components. In addition, the analysis verifies that energy‐efficient HIPSD can be generated by considering pinch constraints. [ABSTRACT FROM AUTHOR]

Summary: The coexistence of different kinds of waste heat sources on marine vessels with various temperature ranges increases the need for an optimal heat exchanger network (HEN) design for the heat collection process to reduce the unutilizable heat that needs to be discharged to overboard. The optimal HEN design has not been taken into consideration by using pinch point analysis in previous studies of marine organic Rankine cycle (ORC) systems that utilize from different kinds of waste heat sources. The objective of the study is to determine the optimal HEN design for an ORC integrated waste heat recovery system of a marine vessel by utilizing the pinch point analysis to improve the overall energy efficiency. Lubricating oil, high‐temperature cooling water and scavenge air of the main engine, and the exhaust gas emitted from the boiler plant were identified as the major waste heat sources of a reference container ship. A heat collection stream, in which thermal oil is used as the heat transfer fluid that transfers the collected heat to an ORC system, was proposed. The pinch point analysis showed that the optimum waste heat recovery could be gained by separating the scavenge air cooler into three stages and the lubricating oil cooler into two stages. The results of the parametric study for the varying evaporator inlet pressure between 1000 and 3000 kPa showed that R1234ze(Z) yields the best performance among nine different organic working fluids with the thermal efficiency and exergy efficiency of 15.24% and 86.47% for the ORC system, respectively. For the proposed configuration, the unavailable waste heat that cannot be transferred to thermal oil was found as 23.71%, 16.56%, 13.17%, and 7.81% of the total waste heat produced by the heat sources, and also 8.24%, 9.80%, 11.55%, and 12.93% of the net power output produced by the main engine can be recovered for 25%, 50%, 76%, and 100% maximum continuous rating (MCR), respectively. [ABSTRACT FROM AUTHOR]

Raw material management plays an essential role in the environment production and carbon emission problem. A P‐graph is an effective tool that can be used to solve the raw material management problem. However, raw material management based on the P‐graph is complicated and inaccurate. Therefore, this paper proposes an improved P‐graph integrating carbon emission pinch analysis (CEPA‐P‐graph) method to resolve raw material management problem with simpler structures and less results. The proposed method is applied in raw material planning in terms of the regional energy planning problem, and two ethylene plants under carbon emission constraints are examined. As the parameter information of the problem is utilized by pinch technology, the search domain of structure optimization is further reduced, and the computing complexity is reduced, while the advantages of the P‐graph multi‐solution are guaranteed. The experimental results demonstrate the validity of the proposed method. Furthermore, the CEPA‐P‐graph could reduce the complexity of solution structure generation by ~70% and reduce the carbon emission per unit product by 17%. [ABSTRACT FROM AUTHOR]

This paper proposes a probabilistic power pinch analysis (PoPA) approach based on Monte–Carlo simulation (MCS) for energy management of hybrid energy systems uncertainty. The systems power grand composite curve is formulated with the chance constraint method to consider load stochasticity. In a predictive control horizon, the power grand composite curve is shaped based on the pinch analysis approach. The robust energy management strategy effected in a control horizon is inferred from the likelihood of a bounded predicted power grand composite curve, violating the pinch. Furthermore, the response of the system using the energy management strategies (EMS) of the proposed method is evaluated against the day-ahead (DA) and adaptive power pinch strategy. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a case study on improving the energy integration of a gas‐based ethylene process by focusing on major sources of thermal exergy losses. Exergy analysis is used to find the main sources of thermal exergetic inefficiency. Thermal solutions are then developed, leading to a comprehensive list of cold and hot process streams that could potentially reduce exergy losses from these sources. Pinch analysis is then carried out to screen these streams so only those, which can minimize the energy requirement, are maintained. Besides this, pinch analysis is used to select utilities and to explore cogeneration potential. Thus, the methodology used in this paper takes advantage of both exergy and pinch analyses, in a way that all the possible thermal solutions supported by exergy analysis are considered, preventing exclusion of any hot or cold process stream with high potential for heat integration during pinch analysis. [ABSTRACT FROM AUTHOR]

Reducing thermal energy use in industry is an effective way to improve energy efficiency. Process integration methods tackle this challenge, of which pinch analysis is a popular approach for identifying direct heat recovery measures. Many processes are batch processes that can profit from indirect heat recovery using thermal energy storage (TES). This paper presents a systematic conceptual TES integration methodology. In addition, functionality to support this methodology has been implemented in the PinCH software and is presented in a case study. [ABSTRACT FROM AUTHOR]

For design of a heat exchanger network (HEN) by pinch technology, it is not uncommon to determine stream splitting and stream matching by empirical experience, in which numerous attempts are usually required to reach the final configuration of the HEN. In this work, a novel T-Q diagram method is proposed to integrate large-scale HENs on the basis of partitioning and merging heat recovery intervals. It aims at reducing the difficulties of the stream matching process for large-scale HENs. The implementation procedure is illustrated via a simple HEN design problem. Furthermore, the HEN of a vacuum distillation unit in a refinery is used to further demonstrate the advantages and versatility of the proposed method. The results indicate that the proposed method can reduce the computational effort required and obtain a cost-effective design of large-scale HENs. Therefore, it provides an effective graphical analysis tool for the integration of large-scale HENs in practice. [ABSTRACT FROM AUTHOR]

Heat from compression processes is normally wasted to cooling water due to its low temperature or concerns about operability. The recoverable amount of heat can be enhanced by increasing the operating temperature of compressors. However, the compression work also increases under this condition. The integration of compressors into heat exchanger networks (HENs) is complex since both heat and work are involved, and the role of streams (as hot or cold streams), the utility demand, and the location of pinch points may change. A systematic graphical design procedure for above ambient HEN design including compressors was presented. The objective is to minimize exergy consumption to balance the complex heat-work trade-offs involved. Four theorems are proposed as the basis of the design procedure with certain well-defined assumptions. It is found that the compression should be performed at pinch or ambient temperatures to achieve minimum exergy consumption. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3770-3785, 2015 [ABSTRACT FROM AUTHOR]

The integration of expanders into heat exchanger networks (HENs) is a complex task since both heat and work are involved. In addition, the role of streams (as hot or cold), the utility demand, and the location of pinch points may change. With certain well-defined conditions, four theorems are proposed for the integration of expanders into HENs above ambient temperature with the objective of minimizing exergy consumption. A straightforward graphical methodology for above ambient HENs design including expanders is developed on the basis of Grand Composite Curves (GCCs). It is concluded that to achieve a design with minimum exergy consumption, stream splitting may be applied and expansion should be done at pinch temperatures, hot utility temperature, or ambient temperature. In the majority of cases, however, and in line with the concept of Appropriate Placement from Pinch Analysis, expansion at pinch temperatures gives the minimum exergy consumption. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3404-3422, 2015 [ABSTRACT FROM AUTHOR]

In pinch analysis, the calculations needed for determining pinch temperatures and minimum utility requirements are simple and can be done manually in case of a small number of streams. However, in real-scale industrial problems, the calculation can become tedious and very much time-consuming. A generalized low-cost and user-friendly scheme for pinch design using MATLAB is proposed. This scheme is tested for several problems for accuracy and robustness to determine hot pinch temperature, cold pinch temperature, minimum cooling load, and minimum heating load using the temperature interval method. The solutions developed by the proposed scheme are mirror images of solutions found by applying a rigorous procedure. [ABSTRACT FROM AUTHOR]

ABSTRACT Appropriate integration of subsystems results in an energy-efficient and cost-effective design of the overall system. In many industrial applications, heat transfer fluid (HTF) is used to supply required amount of heat to multiple heat demands from a single heat source. Appropriate integration of fired heater with a process leads to overall reduction in energy requirement as well as capital investment. In this paper, four methodologies are developed to integrate fired heater appropriately with a process. Firstly, a targeting methodology is proposed to determine the minimum HTF flow rate to supply heat from single heater to multiple heat demands. Secondly, a methodology to integrate radiant fired heater with a process through HTF is discussed. Thirdly, indirect integration of fired heater, incorporating energy recovery from flue gas through the air preheater, is developed. Finally, improvement of overall energy efficiency by utilizing process heat below pinch through air preheating is demonstrated. It is also illustrated that the number of fired heater can be reduced, and hence, the total cost of the system can also be reduced by indirect integration. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY Pinch point analysis can be adapted so as to assist in the early stages of designing the Organic Rankine Cycle (ORC) systems. Typically used in determining the working parameters of heat exchangers, it can be employed to improve the heat fitting between the source of heat and the working fluids of the ORC system. To attain the parametric match, an algorithm was built enabling quick estimation of the possible heat reception by the specific working fluid. In effect, it is now possible to attain quick estimation of the upper limits of the electrical power output and the overall conversion efficiency. This paper outlines the developed algorithm and the range of its possible applications and presents the results of sample calculations. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The purification reuse/recycle is one effective resource conservation strategy. In this article, a novel conceptual method is proposed to identify the optimal purification feed flow rate (PFFR) and the corresponding maximum hydrogen utility savings (HUS) of the hydrogen network with purification reuse/recycle. In this method, the sources and sink-tie-lines are divided into three regions according to the purified product and purification feed. The quantitative relationship between the HUS and the PFFR is analyzed for the sink-tie-lines and sources of each region. With the quantitative relationship line between the HUS and the PFFR of each source plotted, the quantitative relationship diagram can be obtained and can be used to identify the pinch point and the HUS for a given PFFR. Furthermore, the optimal PFFR and the maximum HUS can be identified easily. Three cases are studied to illustrate the applicability of the proposed method. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1964-1980, 2013 [ABSTRACT FROM AUTHOR]

The article presents a study which developed an algorithmic decomposition procedure that will identify an optimum strategy for integrating sources and demands to minimize the external resource requirement. A network flow optimization problem called segregated targeting of resource network has been proposed and solved. The use of the procedure in conjunction with different pinch targeting methods was illustrated by solving case studies on carbon-constrained energy planning, interplant water integration and emergy-based allocation of fuel resources.

The article focuses on the use of the Systematic Hierarchical Approach for Resilient Process Screening (SHARPS) as a cost-screening tool for design and retrofit of minimum water network for urban and industrial sectors. The methodology involved in implementing the SHARPS technique is presented. A correlation is given between the total payback period (TPP) and the maximum desired payback period (PP) set by a designer. Substitution and intensification strategies may be implemented if the TPP is more than PP.

An algorithm is proposed to target the minimum freshwater for fixed flow rate (FF) problems in single-contaminant water networks. The approach is based on an extension of the limiting composite curve concept proposed earlier for fixed contaminant-load (FC) problems. The targeting method is elegant, noniterative, and can be applied to FF problems involving regeneration to minimize waste discharge. To design networks that achieve the minimum freshwater targets set for FF problems, an algorithm is presented based on the principle of nearest neighbors. The principle simply states that the sources to be chosen to satisfy a particular water demand must be the nearest available neighbors in terms of contaminant concentration. A significant advantage of the approach is that the same targeting concepts can be profitably used to determine the minimum makeup utility in hydrogen networks. Furthermore, hydrogen networks may be designed by the unified conceptual approach using the nearest neighbors algorithm. The hydrogen networks may then be evolved to account for the pressure constraints imposed by compressors or improved by regeneration through purification processes such as pressure-swing adsorption. [ABSTRACT FROM AUTHOR]

This work presents the water cascade analysis (WCA) as a new technique to establish the minimum water and wastewater targets for continuous water-using processes. The WCA is a numerical alternative to the graphical water targeting technique known as the water surplus diagram. The WCA is to the water surplus diagram in water pinch analysis (WPA) as problem table analysis (PTA) is to the grand composite curves in heat pinch analysis. By eliminating the tedious iterative steps of the water surplus diagram, the WCA can quickly yield accurate minimum water targets, pinch point locations, and water allocation targets for a maximum water recovery (MWR) network, thereby offering a key complementary role to the water surplus diagram in the synthesis of water network. As in the case of the water surplus diagram, the WCA is not limited to mass-transfer-based operations and is applicable to a wide range of water-using operations. [ABSTRACT FROM AUTHOR]

Invariant rectifying-stripping (IRS) curves are presented for energy analysis of distillation processes. The IRS curves are invariant to the column configuration (that is, feed location and total number of stages) and depend only on the separation problem and the operating pressure of the column. IRS curves are useful to set targets without performing multiple simulation studies. A novel method is proposed to extend the IRS curves, originally developed for simple distillation columns (with single feed and two end products), to complex multiple-feed columns. In the proposed method, a column with n feeds is decomposed into n simple single-feed columns. The IRS curves are generated for these simple columns and the order and location of the feeds are targeted. Then these IRS curves are added in distinct sections demarcated by the feed points to the column to obtain the composite IRS curves for the complex column. Various targets such as minimum energy requirements (that is, minimum condenser and reboiler loads), appropriate feed locations, proper order of feeds, and effect of premixing feeds can be targeted from the composite IRS curves. Thus, the composite IRS curves for complex columns retain all the advantages of the IRS curves established for the case of simple distillation columns. General guidelines are also proposed for appropriate feed preconditioning and sideexchanger duties leading to the design of energy-efficient complex distillation processes. [ABSTRACT FROM AUTHOR]

A coat of paint adds considerable value to an automobile. In addition to consuming up to 60% of the energy needed by automobile assembly plants, however, the painting process also creates both economic and environmental impacts. This study investigated the degree of cost and environmental impact improvement that can be expected when modifications are considered for existing paint processes through heat integration. In order to accomplish this goal, a mathematical model was created to describe the energy use, costs, and environmental impacts from energy consumption in an automobile assembly painting facility. The model agrees with measured energy consumption data for process heating and electricity demand to within about 15% for one Michigan truck facility from which model input parameters were obtained. Thermal pinch analysis determined an energy conservation target of 58% of paint process energy demand. A heat exchanger network optimization study was conducted in order to determine how closely the network design could achieve this target. The resulting heat exchanger network design was profitable based on a discounted cash flow analysis and may achieve reductions in total corporate energy consumption of up to 16% if implemented corporatewide at a major automobile manufacturer. [ABSTRACT FROM AUTHOR]