Application Of Pinch Analysis Research Articles

Graphical Prediction of Optimum Pinch Point Value with AEA Software Simulation and Validation Applied in Closed Cycle Gas Power Plant

Studying industries energy saving is very important prospect for many researchers in the last four decades. In this respect, better process heat transfer can be achieved to improve process operating and capital cost. Thereafter, obtaining higher amount of heat recovery, which will help to reach system optimum heat exchanger network design. Application of Pinch analysis (PA) in our current study, was found to be as an effective method towards economic solution and assessment for all system thermal processes. Whereby, minimizing energy losses, and thus, prediction of maximum energy saving. In addition, application of "Aspen Energy Analyzer (AEA)" simulation software assist our effort to optimize Heat Exchanger Network design (HEN), with various application scenario towards best design. This study represents a "Case study" as a Brayton closed cycle gas turbine power plant in Al-khairat district, which is one of a number of sites used to generate electricity for Iraq national grid. However, the plant original design is open cycle. This study, represent an attempt to apply (PA) in system closed cycle model with the same working conditions. The results predicted, on the contrary of open cycle, that using closed cycle (PA) with temperature difference ∆Tmin can be acceptable with several design propositions. The optimum (∆Tmin = 15℃) were evaluated in the closed cycle system pinch analysis, thereby the maximum Qrec. process that minimize the QHmin & QCmin requirement were identified by the software simulation for the best HEN design. These results were found as Qrec. = 318.330 MW, QHmin = 88.607 MW and QCmin =39.564 MW.

Adapted Time Slice Model of Pinch Analysis for Direct-Indirect Heat Recovery in Buildings

Heat integration techniques such as pinch analysis can play a significant role in saving energy in the design of buildings. The application of pinch analysis in this sector encounters difficulties due to the highly time-dependent behavior of energy streams such as waste heat and solar thermal collectors, as well as the possible need for heat storage units (HSUs). The existing pinch models in the literature either bear little relation to reality because they ignore the time dependency of the streams, or they do not respect the pinch analysis minimum temperature difference of the system, which leads to temperature penalties. This study introduces a novel and straightforward adapted time slice model of pinch analysis, beneficial for energy targeting in buildings. First, an algorithm for the selection of the appropriate time slice duration is proposed. Then, additional steps are embedded in the conventional problem table algorithm to account for both direct heat transfer (co-existing streams) and indirect heat transfer (time mismatched streams requiring thermal energy storage). i.e., the modified table includes both external and internal streams, respectively. The detailed application of the proposed model is demonstrated through the analysis of a direct-indirect heat recovery system for a residential test building equipped with waste heat and solar energy, considering a summer’s day. This case study, or sample calculation, determines the HSU specifications, including their design temperatures and volumes. A heat exchanger evaluation quantifies both their number and their thermal conductances, which are an economic indicator of the system capital cost.

Application of pinch analysis to improve the heat integration efficiency in a crude distillation unit

In this paper, the thermal efficiency of the heat exchanger network of an existing crude distillation unit (CDU) was evaluated. The main goal is to determine how much energy savings can be achieved by network retrofitting. Energy losses are inevitable especially in process where equipment and heat integration network design are outdated. Pinch analysis method can help in minimizing the energy losses by retrofitting the heat exchanger grid and it is proven to be successful in many applications to predict more efficient heat exchanger networks. A base scenario case study was suggested to determine the maximum possible energy savings that can be achieved. In this scenario, the energy analyzer model in Aspen HYSYS was used to determine the optimum energy network that can accomplish maximum energy recovery with minimum capital cost. Another alternative was also evaluated using pinch analyzer tools in Aspen HYSYS. In this scenario, the existing heat exchanger network was optimized to determine how much energy can be recovered. All analysis conducted were based on the existing cooling and heating utilities in the plant. The results obtained indicate that around 67.5 MW of maximum cooling and heating utility can possibly be recovered compared to the existing utility load of 148.6 MW. This represents around 45% reduction in heat utility requirements. There is also an indication of substantial positive environmental impact in terms of how much reduction in the CO 2 emissions that can be achieved reaches up to 1079 kg CO 2 /h for a practical and feasible option, and up to 7840 kg CO 2 /h for grass rooting retrofitting scenario.

Pinch Analysis For Styrene Production With Lummus/UOP Smart SM Technology

Styrene is an organic compound used for the synthesis of polymers, co-polymers, and rubber. Generally, the reaction to form styrene comes from the dehydrogenation of ethylbenzene. This reaction occurs when the compound is in the vapor phase and is endothermic. One of the technologies for ethylbenzene dehydrogenation is Lummus/UOP Smart SM. This technology uses oxygen to heat the reaction and makes the hydrogen disappear, so the reacting reaches the highest ethylbenzene conversion. The focus of this research was pinch analysis on Lummus/UOP Smart SM. The first step in pinch analysis is data extraction. An alternative is to perform pinch analysis with a composite curve, problem table, shifted composite curve, and grand composite curve. Then is continued to create a design Heat Exchanger Network (HEN). The application of pinch analysis to evaluate heating duty, cooling duty, Maximum Energy Recovery (MER), and determine the exact HEN for optimal energy. In this research, the integration of the process showed not optimal results, especially in cooling duty, because the energy recovery was obtained small, and for heating duty saved about 14%.

Gas Flare Design Debottlenecking Using Pinch Analysis

Gas flaring is concerned with the combustion of lighter ends of hydrocarbon mostly produced in association with crude oil. Flare networks are designed to handle the gas volume required to be flared. Most times, this flare networks are in close proximity but still have independent flare stacks, increasing risk to environment and cost on infrastructures. There is a need to integrate the flare networks in facilities within same area and through the application of Pinch Analysis concept, the resultant flare network can be optimized to give a system having optimal tail and header pipe sizes that will reduce cost and impact on environment. In the light of the foregoing, the concept of pinch analysis was used in debottlenecking integrated gas flare networks from a flow station and a refinery in close proximity. Both flare networks were integrated and the resultant gas flare network was optimized to obtain the optimum pipe header and tail pipe sizes with the capacity to withstand the inventory from both facilities and satisfy the set constraints such as Mach number, noise, RhoV2 and backpressure. Mach number was set at 0.7 for tail pipes and 0.5 for header pipes, noise limit was not to exceed 80 dB upstream and 115 dB downstream the sources, RhoV2 was limited to 6000 kg/m/s2 and the back pressure requirement was source dependent respectively. The fire case scenario was considered, as it is the worst-case scenario in the studies. When pinch analysis was applied in debottlenecking the combined gas flare network, it gave smaller tail and header pipe sizes which is more economical. A 20% decrease in pipe sizes was recorded at the end of the study.

Pinch Analysis as a Quantitative Decision Framework for Determining Gaps in Health Care Delivery Systems

With “good health and well-being” being set as one of the targets of the Sustainable Development Goal (SDG), this paper proposes the application of pinch analysis, a quantitative method originally applied to conserve scarce resources in source-demand allocation networks, for identifying gaps in health care service delivery. This method is also found to be useful for health care infrastructure capacity planning and policy testing. The major contribution of this method in this context is identification of marginalized sections and testing specific policies targeted towards them, which will justify release of financial aid and infrastructure development for appropriate sections. We explored this concept for investigating the in-patient health care delivery system in the context of developing nations, where the health care facilities (both public and private) thrive by offering services at drastically different prices. A novel framework is developed in this paper, supported by a case study of Kolkata, India where both the gaps and surplus in the health care services faced by different sections of population are identified. In order to offset these gaps, we offer recommendations for possible policy implementation. A few hypothetical scenarios are also examined in order to understand the importance of pinch analysis for policy testing. We conclude by proving that pinch analysis can be a robust integrated decision-making framework for the health care sector, especially in resource-constrained communities.

The Role of Pinch Analysis for Industrial ORC Integration

In many industrial companies a significant proportion of their total energy use is for process heat resulting in the need for improving thermal energy efficiency. A common technique to improve efficiency is through process heat recovery. Pinch analysis is a key method for optimizing industrial heat recovery resulting in greater energy efficiency and profitability. The method also shows how energy conversion units such as heat pumps, combined heat and power systems or organic Rankine cycles (ORC) can be optimally integrated into a process. An ORC converts low temperature waste heat (e.g. 100-200°C) into electricity. However, the integration of an ORC requires a sound conceptual design to ensure proper integration. In this paper the importance and application of pinch analysis for integrating an ORC is presented. Pinch analysis plays a significant role in the development of a sound conceptual design as it identifies and quantifies the amount of waste heat as well as allows the determination of the streams most suitable for the ORC. The so called grand composite curve is used for the integration of an ORC to ensure the proper placement when considering the entire process. A properly integrated ORC that uses waste heat as a heat source must operate below the pinch point, i.e. the ORC takes heat from below the pinch point and converts a part of it to electricity and rejects the remaining heat to the environment. This methodology stresses improving the overall process energetic efficiency first through heat recovery before using (real) waste heat in an ORC. A novel industrial case study is presented to illustrate proper ORC integration showing the benefit energetically but limited financially under the given process and economic conditions.

Application of exergy analysis to improve the heat integration efficiency in a hydrocracking process

Heat integration techniques are now widely used for energy saving in petroleum processes. In this paper, an industrial hydrocracking process (UOP license) is retrofitted by pinch analysis as a significant tool for heat integration. The hydrocracking process is a main important conversion process in oil refineries and there has been sustained effort to improve its energy efficiency. Application of pinch analysis in retrofit of this process shows the heat exchanger network is operated efficiently. However, a large amount of energy is wasted from the hydrocracking unit, which their condition make no of use directly by the process during pinch analysis. Actually, most of the refining petroleum processes use considerably more energy than the operational minimum energy requirements because of their energy losses. These external energy losses are due to many factors, including normally inefficient or outdated equipment and process design, inadequate heat recovery, and poor integration of heat sources and sinks. However, without identifying the quality of the energy losses, it is difficult to determine how much of that energy is feasible to recover under realistic plant operating conditions. This is where exergy analysis can significantly assist in determining energy recovery opportunities. Thus, this paper is addressed to researchers who are assessing the quality of energy wasted in hydrocracking process, by using the principles of both pinch and exergy analysis. Based on the result obtained, the flue gas exhaust and the high pressure drop in reaction section can be considered as the exergy loss sources in this process. Moreover, the portion of waste energy that can be practically recovered is quantified.

Benchmarking of olefin plant cold-end for shaft work consumption, using process integration concepts

The olefin plant is all about separating cracked gas into ethylene, propylene and other heavier by-products using low-temperature gas separation processes. This process is energy-intensive and hence retrofitting for energy saving would be desirable. However, a full retrofit study requires a lot of time and costly engineering work. So, a novel method is introduced in this paper for benchmarking of shaft work consumption in olefin cold-end, which is based on process integration concepts. In developing this method, the amount of shaft work required in refrigeration cycles was first targeted via application of Pinch Analysis to six different olefin plants followed by the calculation of feasible and achievable energy saving potential. When doing so, the effect of predominant factors such as plant capacity, feedstock (naphtha or natural gas), products specification and type of technology being used was investigated as well. Finally, a mathematical model was developed for rapid estimation of energy saving potential using the above key factors. This model was verified through case studies and was proved to be accurate enough for shortcut calculations.

Waste Management Pinch Analysis (WAMPA): Application of Pinch Analysis for greenhouse gas (GHG) emission reduction in municipal solid waste management

Improper waste management happened in most of the developing country where inadequate disposal of waste in landfill is commonly practiced. Apart from disposal, MSW can turn into valuable product through recycling, energy recovery, and biological recovery action as suggested in the hierarchy of waste management. This study presents a method known as Waste Management Pinch Analysis (WAMPA) to examine the implication of a dual-objective – landfill and GHG emission reduction target in sustainable waste management. WAMPA is capable to identify the capacity of each waste processing strategy through graphical representation. A general methodology of WAMPA is presented through a demonstration of a SWM case followed by a detailed representation of WAMPA for five waste types. Application of the WAMPA is then applied on a case study for sustainable waste management planning from year 2015 to 2035. Three waste management strategies are incorporated into the case study – landfill, Waste-to-Energy (WtE), and reduce, reuse, and recycle (3R). The results show a 13.5% of total GHG emission reduction and 54.6% of total reduction of landfill are achieved. The major contributor of GHG emission which are from food waste (landfill emission) and plastic (WtE emission) is reduced.

Application of Pinch Analysis in an Integrated Steel Plant in Northern Sweden

The energy system in a modern integrated steel plant is a complicated network of units exchanging energy and matter with each other. System studies using process integration tools are important to avoid sub-optimization. At the steel plant in Luleå such studies have been carried out using a MILP-based mathematical programming tool (reMIND), mainly because of its inherent flexibility for handling combined flows and reactions of both matter and chemical, thermal and mechanical energy. There are, however, areas where the energy system is dominated by creation, transport and exchange of thermal energy, and where pinch analysis can be expected to be a valuable tool. For this reason a pinch targeting study was carried out for the plant site of the integrated steel plant in Luleå. The coke plant and the iron making/steelmaking plant were both studied with three ambition levels of possible improvements. The study confirmed that pinch analysis is a powerful tool for targeting energy savings in areas where thermal energy flows dominate the local energy system, e.g., the gas cleaning area at the coke plant. The study also indicated that a connection between the energy systems in the coke plant and the iron making/steelmaking would be valuable. This is not 100% feasible because of distance, but, a common steam net could add a degree of flexibility.

Integrated gasification combined cycle (IGCC) process simulation and optimization

The integrated gasification combined cycle (IGCC) is an electrical power generation system which offers efficient generation from coal with lower effect on the environment than conventional coal power plants. However, further improvement of its efficiency and thereby lowering emissions are important tasks to achieve a more sustainable energy production. In this paper, a process simulation tool is proposed for simulation of IGCC. This tool is used to improve IGCC's efficiency and the environmental performance through an analysis of the operating conditions, together with process integration studies. Pinch analysis principles and process integration insights are then employed to make topological changes to the flowsheet to improve the energy efficiency and minimize the operation costs. Process data of the Texaco gasifier and the associated plants (coal preparation, air separation unit, gas cleaning, sulfur recovery, gas turbine, steam turbine and the heat recovery steam generator) are considered as a base case, and simulated using Aspen Plus ®. The results of parameter analysis and heat integration studies indicate that thermal efficiency of 45% can be reached, while a significant decrease in CO 2 and SO x emissions is observed. The CO 2 and SO x emission levels reached are 698 kg/MWh and 0.15 kg/MWh, respectively. Application of pinch analysis determines energy targets, and also identifies potential modifications for further improvement to overall energy efficiency. Benefits of energy integration and steam production possibilities can further be quantified. Overall benefits can be translated to minimum operation costs and atmospheric emissions.

From process integration to eco-industrial systems

Process integration methods were first used to develop heat recovery strategies in industrial plants for purposes of energy conservation (Linnhoff et al. 1982). Not surprisingly, commercial interest in the early process integration tools such as thermal pinch analysis coincided with the global energy crises in the late 1970s. These early tools allowed analysts to determine energy targets for industrial facilities and also provided heuristics for the detailed design of heat recovery networks. More recently, the field of process integration has been extended to include procedures for the conservation of material inputs for process plants. El-Halwagi (1997) gave a comprehensive description of many such techniques for efficient use of such resources based on the analogy between heat and material flows. Much work has been done in particular on the minimization of water use in industry. The seminal work of Wang and Smith (1994) pioneered the conceptual, insightbased pinch analysis school of thought. Meanwhile, mathematical programming approaches were also applied for similar problems, for example by Takama et al. (1980). An early review by Bagajewicz (2000) describes both pinch analysis and optimization based approaches, although many more advances have since been made in the field of industrial water reuse. In any case, the central premise in the field of process integration is the cascading of energy or material streams from high-quality applications to low-quality ones, and the bulk of the scientific literature in this field covers the development of design methodologies for various problem scenarios. Meanwhile, the field of industrial ecology has emerged based on a parallel concept. The field is founded on emulating cyclic flows found in natural ecosystems in order to minimize the use of resources and the generation of wastes in industrial systems (Graedel and Allenby 1995; Korhonen 2004). As in process integration, such cyclic flows are possible through cascading material flows through applications of progressively lower grades. Hence, the analogies between the two fields are inevitable, except that in process integration, the exchange of streams occurs among process within an industrial plant, while in industrial ecology such exchanges are made between industrial plants. The potential for design methods in the former discipline to be used in the latter field was first proposed by Spriggs et al. (2004). In particular, many pinch analysis procedures allow energy or material consumption targets to be identified; these figures then serve as useful benchmarks for designers, who must then identify waste stream exchange network configurations that allow such targets to be achieved, or at least approached. Exactly how far can the analogy be taken? It has been noted by many observers that eco-industrial systems which have implemented such symbiotic networks have often emerged spontaneously or at least with minimal direction from any centralized authority (Korhonen 2004; Posch 2004; Koenig 2005). Thus, the optimization-based ethos underlying the field of process integration may not be entirely applicable to industrial ecology. The main stumbling block is that each plant or organization that might participate in eco-industrial symbiosis has its own interests, which may not coincide with those of its potential partners. In contrast, process integration is applied within a single organization, which implies the existence of a centralized authority to direct any system-level changes. At best, conventional process integration tools may be used in a manner analogous to the application of pinch analysis for targeting; they can provide planners with an idea of the R. R. Tan (&) De La Salle University-Manila, Manila, Philippines e-mail: tanr_a@dlsu.edu.ph

Pinch analysis approach to carbon-constrained energy sector planning

Pinch analysis techniques have been developed for a wide range of applications ranging from process plant thermal or water integration to financial and supply chain management. This paper presents a new application of pinch analysis. A scenario is assumed wherein energy sector planning takes place with carbon emission constraints arising from an effort to reduce climate change effects. A procedure for identifying the minimum amount of zero-carbon energy resource required to achieve the overall emissions target for a country or region, given that the amount of fossil energy resources available are already known. The pinch analysis method can be used for a single overall emissions target, or for cases wherein separate sectors or geographic regions have distinct targets but share a common energy resource. For the latter case the procedure allows the allocation of the energy resources to meet both the overall emissions limit and the individual targets of the different sectors or location. Numerical examples are provided to illustrate the technique, which is intended for use as a preliminary energy sector-planning tool.

The application of pinch analysis to water, reagent and effluent management in a chlor-alkali facility

South African industry is coming under increasing pressure to reduce the amount of freshwater it uses and the amount of effluent it produces. Water pinch is a cleaner production technique aimed at reducing the freshwater consumption and effluent production within a chemical complex. The design of water-reuse or water pinch networks as applied to the case study of a chlor-alkali complex is considered. Insights are provided into the analysis and formulation of problems for large-scale industrial systems and the application of present techniques and tools to the formulated problem is illustrated. The features of the problem posed by the chlor-alkali facility are discussed and the limitations of the present theory in dealing with this problem highlighted. The concepts of utility-waterpinch analysis and process-water pinch analysis are introduced.