Pinch Technology

Methanol is an important industrial chemical, and its synthesis and purification units are among the most widely used processes in the field of energy. The two-column separation unit of methanol has been analyzed from the thermodynamic and energy points of view in the present study. The simulation has been done by Aspen Hysys V11 and the SRK equation has been regarded as the most appropriate equation of state (EOS) for this simulation with the mean relative error (MRE) of 2 %. Then, the design of the heat exchanger network (HEN) has been calculated using the Aspen Energy Analyzer V11. Both distillation towers have been analyzed using pinch technology. As a result, the amount of hot and cold utilities used has been LP=1.482×〖10〗^8, MP=1.57×〖10〗^4, and Air =1.423×〖10〗^8, respectively. Besides, the total heating and cooling target of the process has been 1.482×〖10〗^8 and 1.423×〖10〗^8, accordingly. Then, the 〖∆T〗_min (minimum allowable temperature difference between hot and cold currents) and its effect on the annual cost have been investigated. The optimum value 〖∆T〗_min is determined to have better-operating conditions and to meet the design of the HEN economically. Reducing 〖∆T〗_min increases operating costs and reduces energy costs.

Distillation is an important and widely applied separation method. One of its major application areas is crude oil refining. We investigate and compare two different refinery technologies: (i) conventional, atmospheric and vacuum, AV-plant, and (ii) an alternative one, the so-called progressive distillation technology. For the sake of the comparison, simulation models of the two different distillation technologies are built in professional flowsheeting software environment. The investigation includes the study of crude oil fractionation on the examples of processing different types of crude oils. Both technologies are also evaluated with the tools of pinch technology. On the basis of the results of the pinch analysis, heat exchanger networks are also designed. The operating and capital costs are estimated for the energy integrated cases designed on the results of pinch technology. A comparison of the results shows that the progressive distillation plant proves to be both more energy efficient and economical than the currently applied atmospheric and vacuum distillation plants.

The olefin plant cold-end is aimed at separating cracked gas into ethylene, propylene and other heavier byproducts 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.

Han pasado los años, desde aquel octubre de 1978, en que por vez primera conocí su maestría en la docencia de la Botánica, como a él le gustaba "en el campo", observando las plantas con toda la ilusión que la naturaleza puede ofrecer. Ese mismo día, con una generosidad digna de elogio, me ofreció su talento y sus conocimientos, para que, junto a él, iniciara mis pasos en el apasionante mundo de la vida vegetal, hecho que marcaría mi vida, pues desde entonces, este campo del saber ha ocupado mi tiempo, esfuerzos y como no, mi felicidad. Esos primeros años formamos un equipo inseparable, siempre inquieto, para conseguir que la tesis de licenciatura sobre la flora y la vegetación de los yesos y saladares de Granada fuese un trabajo digno y responsable. En ese momento contábamos, además, con el apoyo de D. Fernando Esteve Chueca, maestro en la investigación que sobre Sierra Arana, fue motivo de su tesis doctoral, quien le ofreció además la posibilidad de venir a nuestra ciudad desde su Canarias natal…"nunca perdió ese acento tan especial en su forma de hablar". Tras la tesina, un nuevo impulso nos llevó a la preparación de artículos científicos para su publicación en revistas de alta especialización: vieron la luz algunas aportaciones para la flora de Granada, comunidades vegetales nuevas o poco conocidas, especies nuevas (siempre hemos recordado nuestras anécdotas con el Limonium malahaense) y, como no, las exiccatas que durante varios años nos proporcionaron mucho trabajo y buenos ratos en las campañas botánicas que con otros compañeros disfrutamos por toda Andalucía. Además, durante estos treinta años, su fidelidad a las dos líneas de investigación que más le entusiasmaban, obtuvieron de su parte unos prolíficos resultados. La minuciosidad en los estudios taxonómicos de las "sideritis" y la paciencia para identificar los pólenes que forman parte de las mieles que consumimos, se plasmaron en excelentes libros y artículos que han quedado para el disfrute y admiración de la comunidad científica. Sus estudios de Biología y Farmacia le animaron a impartir docencia en ambas facultades, teniendo un reconocimiento unánime del alumnado, en cuanto a su excelencia, impartiendo lecciones magistrales de Botánica. También los miembros del departamento hemos disfrutado de su compañía, tertulia, buenos consejos y, cómo no, una "cerveza fría" después de un agotador pero reconfortante día de campo. Te has marchado tranquilo, en el tenue sueño de una noche temprana de otoño, pero cuesta, cuesta mucho pensar en tu ausencia, aunque estoy seguro de que todos nos volveremos a encontrar en el infinito de nuestras creencias. Oswaldo, amigo, gracias.

Pinch technology is a methodology used in the optimization and dimensioning of heat exchanger networks, initially developed by Hohnmann and Linnhoff during the oil crisis in the mid 70's and 80's. With greater energy efficiency and consumption reduction. In  this  work,  a  computational  algorithmwas  developedusing the  Matlab  tool  and  its  extension  for  process  simulation, Simulink, in order to  apply  the  principles  of  Pinch  technology in the computational resolution of a problem situation involving a  network  of  heat  exchangers.  Initially,  a  problem  situation involving Pinch technology was selected, which was solved by traditional method.From this, the computational algorithm was developed  in  Matlab,  based  on  the  principles  of  Pinch technology and using data belonging to the problem selected for study; performing a comparison of the original data and those found by the algorithm to validate the developed program. After validating the Matlab algorithm, Simulink was used to develop a  program  in  block  language,  to provide  a  better  graphic visualization of theobtainedresults, comparing them again with the results of the traditional method. The results obtained by the algorithms  in  Matlab  / Simulink  were  the  same ones  obtained by  the  traditional  method,  thus  validating  the  programs developed in this research, thus being able to assist future works that  aim  to  deepen  the  computational  application  of  Pinch technology.

RESUMEN: Se aportan datos sobre la distribución y ecología de Lythrum portula (L.) D.A. Webb y Fumana baetica Güemes en la provincia de Cuenca, dos plantas que constituyen novedad para la flora de dicho territorio. En el caso de F. baetica se amplia considerablemente su área de distribución y se presenta su primera localidad fuera de los territorios béticos. SUMMARY: Some data on ecology and chorology of Lythrum portula (L.) D.A. Webb and Fumana baetica Güemes, two taxa new for the flora of Cuenca, are reported. The latter is reported for the first time in a locality quite far from the Betic mountain range, which much enlarges its distribution area.

Current economic uncertainties and tighter environmental regulations has led industries to consider energy conservation projects more seriously. In this paper, the option of varying the process stream temperature has been suggested as a mean of increasing heat recovery for heat exchanger networks (HEN). Alternatives are generated and assessed using a developed approach. Essentially, the approach involves systematic steps in varying the Hot and/or Cold streams' temperature for each stream in a way that increases the heat recovery approach temperature (HRAT), thus allowing more heat to be recovered. Using the combinatorial method of paths combinations, the adjustment of heat loads for hot and cold utilities from the heat load shifting through the heat exchanger network could be made and assessed accordingly. The changes in temperature made to the streams while exploring each alternative has to be kept within small magnitude i.e., around 1e5 C. A user friendly computer program has been developed for performing the approach in view of the significant number of iterations required. An example is used in this paper to demonstrate the application of the developed approach.

The olefin plant is all about separating cracked gas into ethylene, propylene and other heavier byproducts 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.

Se presenta un listado de plantas vasculares, recolectadas en el sur de la ciudad de Valladolid, con interes corologico. De entre las diecisiete plantas aportadas, destacan las siguientes por representar primeras citas para la provincia de Valladolid: Eup

Se presenta un listado de dieciseis plantas vasculares recolectadas en la comarca de los Montes de Torozos, en la provincia de Valladolid (Espana). De entre ellas es preciso destacar las nuevas citas provinciales de Anthyllis vulneraria subsp. sampaioana (Rothm.) Vasc., Carex liparocarpos Gaudin, Lathyrus filiformis (Lam.) Gay, Margotia gumifera (Desf.) Lange, Orchis champagneuxii Barneoud, Serratula nudicaulis (L.) DC., Trifolium dubium Sibth. y Vicia parviflora Cav.

Se aportan datos corológicos de 22 plantas vasculares presentes en los Montes de Torozos, en la provincia de Valladolid (España). La mayor parte de los taxones se citan por primera vez para la comarca. SUMMARY: Chorological data of 22 vascular plants from Montes de Torozos in Valladolid province, Spain, are shown. The most part of the taxa are new records in this area.

The integration of multiple resources conservation networks is necessary to attain the ever-stringent sustainable goals. This work takes initiatives to develop a heat integrated water network via a proposed Pgraph-based sequential methodology. In the first step, a set of feasible water regeneration networks is generated using the conventional P-graph framework. Then, the obtained feasible networks will be used as the inputs in the second stage which aims to generate various sets of feasible heat exchanger networks. It is worth noting that the second model is solved by an extended P-graph framework (P-HENS) for combinatorial process network optimization. The solutions are then ranked based on the total network cost. To demonstrate the effectiveness of the proposed method, a typical water regeneration network (three sources and three sinks) with multi-contaminants is used. The results show a total of 103 feasible water network structures (water network cost ranging from 0.76 M$/y to 1.18 M$/y). Thereafter, a list of feasible HIWRN can be determined using P-HENS. The top four HIWRNs which offer similar total network cost (~1.639 M$/y) are demonstrated. This proposed method provides valuable insights that allow decision-makers to further select the optimal solution which may be more beneficial as compared to the one obtained via conventional methods.

The Pinch Design Method was developed considering one-phase streams, with constant specific heats (Cp) throughout streams' temperature ranges. Its first stage, the determination of utilities targets and pinch point (PP), is ruled by the number of streams, their temperatures and MCp. But, for changing phase streams, the usual description of the Cp behavior by a constant value can lead to errors in this stage and, hence, in the synthesis one. This work proposes a procedure to deal with these streams and discusses its results through an example involving multicomponent streams. First, bubble (BP) and dew (DP) points of the streams are estimated. Then, changing phase streams are split into sub-streams, using BP and DP as bounds. For each one, an effective Cp is estimated as the division of the enthalpy change by the respective temperature difference. Results obtained show significant changes on the PP, utilities targets and network proposed structure.

Se presentan y comentan 42 taxones de interés corológico para la provincia de Valladolid (España). Todos están escasamente citados en la provincia y 11 de ellos son novedad provincial: Callitriche brutia, Crypsis aculeata, Festuca paniculata, Lathyrus pratensis, Luzula campestris, Molineriella minuta, Nepeta tuberosa, Ononis rotundifolia, Orobanche caryophyllacea, Potentilla cinerea y Rhamnus alaternus. Se incluyen endemismos ibéricos de área restringida, disyunciones biogeográficas y taxones que presentan en el territorio alguno de sus límites de distribución. En algunos casos, se comenta, además, su situación actual en distintos referentes normativos sobre flora amenazada castellano-leonesa.42 taxa of chorological interest of the Valladolid province (Spain) are remarked and commented. All of them are poorly referenced in the province and 11 of them are cited here for the first time: Callitriche brutia, Crypsis aculeata, Festuca paniculata, Lathyrus pratensis, Luzula campestris, Mo...

Fossil fuels have been heavily exploited since the Industrial Revolution. The resulting carbon emissions are widely regarded as being the main cause of global warming and climate change. Key mitigation technologies for reducing carbon emissions include carbon capture and storage (CCS) and renewables. According to recent analysis of the International Energy Agency, renewables and CCS will contribute more than 50% of the cumulative emissions reductions by 2050. This paper presents a new mathematical programming model for multi-footprint energy sector planning with CCS and renewables deployment. The model is generic and considers a variety of carbon capture (CC) options for the retrofit of individual thermal power generation units. For comprehensive planning, the Integrated Environmental Control Model is employed in this work to assess the performance and costs of different types of power generation units before and after CC retrofits. A case study of Taiwan’s energy sector is presente...

The advent of Pinch Analysis as a tool for the design of optimal heat, mass and water recovery network has been one of the most significant advances in the area of process synthesis over the last ten years. This paper presents the key innovations in process integration for conservation of resources and utilities such as heat, water, power, solvent and gas that have been exclusively developed by Process Systems Engineering group, Department of Chemical Engineering, UTM. The ultimate goal of the innovations is to significantly contribute towards sustainability through the development of tools that enables the conservation of such valuable resources to mankind. The tools and techniques developed include the new MATRIX technique for heat recovery network retrofit, cascade analysis technique for setting the minimum resource conservation targets, new graphical techniques for setting water and energy targets, batch water targeting and network design, retrofit network design, retrofit and optimization of new and existing regeneration units, and new holistic framework for minimum water network and a systematic method for economical water design system. Significant inroads have also been in shifting the pinch analysis paradigm from the traditional focus on water minimization for process industry into the domain of urban water systems. These tools have been incorporated in MATRIX, a software for resource conservation developed in UTM. In view of the latest development in pinch analysis for resource conservation, it is envisioned that the tool can yield significant benefits to mankind and bring us a step closer towards achieving our ultimate goal of sustainable development.

Ventilation systems are known as intensive energy used building engineering system. Heat exchangers are the main equipments used for energy transformation in building engineering systems as well as in ventilation sys-tems. The conventional heat exchangers design methods do not belie the ways for efficiency energy use in building engineering system's heat exchangers. The method of Pinch technology mostly used for industrial process integration that could be applied to analyze possi-bilities of process integration is first time adopted to evaluate processes integration of building engineering systems. The paper deals with analyze of integration possibilities of ventilation system. The approach covers several possible cases of integration. Analysis is based on heat exchangers used for heat recov-ery and heat transfer in ventilation systems modification cases during the heating season. As results for ventilation system integration possibilities there are represented heat exchangers ...

Kilang penapisan minyak sawit lazimnya melibatkan proses penggunaan tenaga yang tinggi. Peningkatan kecekapan tenaga adalah amat penting bagi memastikan keuntungan tercapai. Kertas kerja ini menggunakan teknik analisis jepit bagi memaksimumkan penggunaan semula haba dan meningkatkan kecekapan sistem rangkaian haba sedia ada di kilang penghasilan minyak sawit, tertakluk kepada kekangan–kekangan proses. Langkah–langkah yang terlibat ialah penetapan sasaran guna semula haba maksimum diikuti dengan reka bentuk rangkaian haba yang ekonomik. Aplikasi teknik berkenaan kepada kilang penghasilan minyak sawit telah menghasilkan pengurangan penggunaan haba panas dan sejuk sebanyak 700 kW (21%), atau penjimatan kos utiliti sebanyak RM370,787, dengan pelaburan kapital sebanyak RM656,293 dan jangka pulangan balik selama 1.77 tahun. Kata kunci: Analisis jepit; minyak kelapa sawit; sedia ada; rangkaian pemindahan haba; kitar semula haba maksimum A palm oil refinery involves energy–intensive process...

In this paper, the optimum design, operation and control philosophy were studied to minimize the process losses in a condensate fractionation plant. Pinch analysis was done for optimum energy usage in the plant. Energy losses once identified can be reduced with little investment. Remarkable savings can be obtained through an energy saving program. Important savings can also be made with operational improvements in the process and better maintenance of production equipment such as distillation column, heaters, heat exchangers etc. Saving energy and proper maintenance of equipments in the process will also reduce the amount of gas emissions and fuel gas consumption and increase plant's lifetime. Aspen-HYSYS and Aspen Energy Analyzer was used as a process simulator and energy analyzer accordingly. Study on energy savings, operating conditions and its environmental impact in a local fractionation plant is presented.

The Pinch technology, seeks an energy integration, which aims to harness the thermal process potential, seeking thus minimal power consumption and number of heat transfer utilities. This work is related to the study of Technology Pinch, with the main objective develop a case study on the implementation of this energy integration tool in a business of the state of Sergipe. The research strategy adopted was the case study and survey data a site visit to a producer of lime company was held (calcium oxide - CaO), to collect evidence, interview and document analysis. Thermodynamic data processing furnace were collected, evaluated and used for construction of the heat exchange diagram.A tecnologia Pinch, busca uma integração energética, que tem como objetivo aproveitar o potencial térmico do processo, buscando, dessa forma, um consumo mínimo de energia e de número de utilidades de troca térmica. Este trabalho está relacionado ao estudo da Tecnologia Pinch, tendo como principal objetivo el...

Ventilation systems are known as intensive energy used building engineering system. Heat exchangers are the main equipments used for energy transformation in building engineering systems as well as in ventilation sys-tems. The conventional heat exchangers design methods do not belie the ways for efficiency energy use in building engineering system's heat exchangers. The method of Pinch technology mostly used for industrial process integration that could be applied to analyze possi-bilities of process integration is first time adopted to evaluate processes integration of building engineering systems. The paper deals with analyze of integration possibilities of ventilation system. The approach covers several possible cases of integration. Analysis is based on heat exchangers used for heat recov-ery and heat transfer in ventilation systems modification cases during the heating season. As results for ventilation system integration possibilities there are represented heat exchangers ...

RESUMEN: Se estudia la diversidad de macromicetos presentes en los diversos ecosistemas de las riberas del río Tormes: bosques de ribera, praderas y pinares, en el tramo Salamanca-Huerta. Se presenta el listado de especies con las recolecciones efectuadas durante los años 2000 y 2001, principalmente, y las citas bibliográficas. Han sido identificadas 111 especies pertenecientes a distintos grupos: Myxomycetes (3), Ascomycetes (6), Basidiomycetes (101) y Ustilaginomycetes (1). Se relacionan 28 nuevas citas para la provincia de Salamanca. El análisis de esta diversidad refleja que la amplia mayoría de las especies se comportan como organismos saprofitos (70%), el 20% como simbiontes y el 10% restante como parásitos de diversas especies forestales.

A heat exchanger network (HEN) for the process of methanol synthesis has been studied by pinch design analysis. Great economic and energy savings were realized by the pinch analysis in comparison to the existing plant. Also, it was found that it is possible to reduce the requirements for the consumption of utilities. The HEN was reconstruded by adding new heat exchangers. In order to produce new HEN, the capital costs had to be increased, but the total cost trade-off between the capital and energy costs will be decrease by 30 %.

RESUMEN: Se aportan datos sobre la distribución y ecología de Lythrum portula (L.) D.A. Webb y Fumana baetica Güemes en la provincia de Cuenca, dos plantas que constituyen novedad para la flora de dicho territorio. En el caso de F. baetica se amplia considerablemente su área de distribución y se presenta su primera localidad fuera de los territorios béticos. SUMMARY: Some data on ecology and chorology of Lythrum portula (L.) D.A. Webb and Fumana baetica Güemes, two taxa new for the flora of Cuenca, are reported. The latter is reported for the first time in a locality quite far from the Betic mountain range, which much enlarges its distribution area.

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

The objective of this research is to retrofit the Olefin Mixture (OM) direct sequence and to analyze the sensitivity with respect to the feed composition. In order to perform the study and analysis, a methodology for retrofitting the direct sequence and analyzing the sensitivity with respect to the feed composition was developed. In Stage 1, a short-cut distillation column design method of process simulator (Aspen HYSYS) is used to simulate the direct sequence. The energy used to separate individual component in the base sequence is analyzed and taken as a reference. In Stage 2, an optimal OM sequence is determined using driving force method. All individual driving force curves for all adjacent components are plotted and the optimal sequence is determined based on the plotted driving force curves. Once the optimal OM sequence has been determined, the new optimal sequence is then simulated in stage 3 using short-cut distillation column design method (using Aspen HYSYS), where the ene...

The Pinch Design Method was developed considering one-phase streams, with constant specific heats (Cp) throughout streams’ temperature ranges. Its first stage, the determination of utilities targets and pinch point (PP), is ruled by the number of streams, their temperatures and MCp. But, for changing phase streams, the usual description of the Cp behavior by a constant value can lead to errors in this stage and, hence, in the synthesis one. This work proposes a procedure to deal with these streams and discusses its results through an example involving multicomponent streams. First, bubble (BP) and dew (DP) points of the streams are estimated. Then, changing phase streams are split into sub-streams, using BP and DP as bounds. For each one, an effective Cp is estimated as the division of the enthalpy change by the respective temperature difference. Results obtained show significant changes on the PP, utilities targets and network proposed structure.

This Special Volume of the Journal of Cleaner Production focuses on the "Sustainability Engineering for the Future". It highlights the roles of present and future engineers and provides guidelines and insights on how sustainability can be embedded systematically into all dimensions of engineering. Gone are the days when engineers only focus on technical and economic feasibility of a system design. The challenges of global warming brought about by widespread environmental pollution, resource depletion, rising human population, and multiple threats to food, water and energy securities require a paradigm shift in engineering thinking and ways to find and test solutions. The evolving engineering paradigm increasingly calls for engineers to consider the whole spectrum of sustainability i.e. from the economic, environmental, social and time dimensions. A selection of papers presented in the 6th International Conference of Process Systems Engineering Asia (PSE Asia) held in Kuala Lumpur, Malaysia from 25th to 27th June 2013 is included in this Special Volume. The papers in this volume focus upon: (i) Important considerations for the planning and development of sustainable products; (ii) Models and methods designed to support sustainable planning and management; (iii) Effective sustainability assessment tools and the needs for new ones; (iv) New approaches for improved resource management; (v) Illustrative future, sustainable technologies; (vi) Ways policies will play significant roles in promoting implementation of sustainable engineering approaches. The collection of papers as designed to provide guidelines for present and future engineers, researchers, academicians and policy makers for ways to improve current and future trends in engineering to help catalyse the transition to truly sustainable societies with improved quality of life.

Excessive energy demand in the unit under study leads to high operating cost and suboptimal design. This is because the unit was design using traditional design energy (TDE) methods prior to the advent of pinch technology. Thus, making it imperative to carry out energy assessment of the unit. The aim of this study is to investigate the energy consumption of the unit via pinch analysis. The methodology includes; data extraction from the process flow diagram (PFD) of the unit, selection of initial value of , targeting (energy and cost), determination of (tradeoff between energy and capital cost) and determination of utilities requirement via composite curves (CCs) and grand composite curves (GCC). The results of the analysis showed that, the optimum is 25 C which results to total annual cost (TAC) of , contrary to the TAC of obtained when of 10 C was selected. This achieved financial saving of 27,000 $/year. Furthermore, the minimum hot and cold utilities demands of the unit are and r...

The industrial application of detailed heat integration to a Di Ethyl Thiophosphoryl Chloride (DETC) plant has been addressed using Pinch design method. The calculated minimum energy targets are found to be very close to utility loads demanded by the existing process. This analysis shows that present plant is well integrated and small saving in energy was observed through a process-to-process energy integration. Alternatively, the retrofit study provides a general guideline for better placement and proper utilization of available utilities.

h i g h l i g h t s g r a p h i c a l a b s t r a c t Modified technique for design Heat Exchanger Networks. New approach for solving problems in Pinch technology. Heat Exchanger Network design based on separate designs of subnetworks for every determined enthalpy interval.

This paper presents a novel Cost Derivative Method (CDM) for finding the optimal area allocation for a defined Heat Exchanger Network (HEN) structure and stream data, without any stream splits to achieve minimum total cost. Using the Pinch Design Method (PDM) to determine the HEN structure, the approach attempts to add, remove and shift area to exchangers where economic benefits are returned. From the derivation of the method, it is found that the slope of the ε-NTU relationship for the specific heat exchanger type, in combination with the difference in exchanger inlet temperatures and the overall heat transfer coefficient, are critical to calculating the extra overall duty each incremental area element returns. The approach is able to account for differences in film coefficients, heat exchanger types, flow arrangements, exchanger cost functions, and utility pricing. Incorporated into the method is the newly defined "utility cost savings flow-on" factor, θ, which evaluates downstream effects on utility use and cost that are caused by changing the area of one exchanger. To illustrate the method, the CDM is applied to the distillation example of . After applying the new CDM, the total annual cost was reduced by 7.1 % mainly due to 24 % less HEN area for similar heat recovery. Area reduction resulted from one exchanger having a minimum approach temperature (ΔTmin) of 7.7 °C while the other recovery exchangers had larger ΔTmin values. The optimum ΔTmin for the PDM was 12.5 °C. The CDM solution was found to give a comparable minimum total area and cost to two recently published programming HEN synthesis solutions for the same problem without requiring the increased network complexity through multiple stream splits.

This paper presents the retrofit of the two-flow heat-exchange system with utility paths in order to optimize the heat recuperation capacity under the technical limitation conditions. Analytical dependences of heat load of the existing heat exchangers and utilities on the surface area of the new heat exchanger are obtained. The work shows that the determination of technological parameters for existing heat exchangers during the retrofit of the heat exchange system is an important task because they affect the cost of retrofit. For case study, two streams problem for heat transfer in heat network at the crude and gas separation units is considered in this paper. The existing system has three heat exchangers. The temperature measurements were fulfilled for all heat exchangers and the heat loads for heat exchangers and utility were calculated. The installation of one heat exchanger at the cool side of the system is proposed in retrofit. The dependences of the temperature changes for the...

Pinch technology is applied on various process flow diagrams from process industries using different strategies or techniques. These techniques include both graphical procedure (Thermal Pinch diagram) as well as algebraic procedure (Temperature interval diagrams) in order to compare the minimum heating and cooling utility requirement of a process with the actual requirement. In this present research work, the process flow diagram of vegetable oil refinery received from an industry. The hot and cold streams are identified and Pinch analysis technology is applied in order to find out the minimum heating and cooling utility requirement. Hot utility reduction is around 21.3% while the cold utility reduction is around 10.2% by Graphical method while the percentage of hot utility reduction is 8.3% and that of cold utility is 4.0% by Algebraic method therefore, the application of graphical method is recommended.

Energy saving is an important issue in process industries due to the increasing cost of energy and associated environmental pollution. Retrofitting of existing Heat Exchanger Networks (HENs) is a key solution to maintain their energy efficiency and minimize utilities consumption. Several graphical methods have been developed for retrofitting design of HENs during the last few years. However, some of these methods are tedious and often leads to complex and uneconomic retrofit. This paper presents a simple graphical retrofit method to cut utility consumption of existing HENs. The new retrofitting method uses a single graph called Supply-Target Diagram (ST-D) to identify and represent potential modifications in existing HENs. A case study is used to illustrate the application of the new graphical method for a retrofitting design of an existing HEN. The addition of two exchangers using the new graphical method shows that heating and cooling utilities can be reduced by 18.75% and 40% res...

A heat exchanger network (HEN) for the process of methanol synthesis has been studied by pinch design analysis. Great economic and energy savings were realized by the pinch analysis in comparison to the existing plant. Also, it was found that it is possible to reduce the requirements for the consumption of utilities. The HEN was reconstruded by adding new heat exchangers. In order to produce new HEN, the capital costs had to be increased, but the total cost trade-off between the capital and energy costs will be decrease by 30 %.

Excessive energy demand in the unit under study leads to high operating cost and suboptimal design. This is because the unit was design using traditional design energy (TDE) methods prior to the advent of pinch technology. Thus, making it imperative to carry out energy assessment of the unit. The aim of this study is to investigate the energy consumption of the unit via pinch analysis. The methodology includes; data extraction from the process flow diagram (PFD) of the unit, selection of initial value of , targeting (energy and cost), determination of (tradeoff between energy and capital cost) and determination of utilities requirement via composite curves (CCs) and grand composite curves (GCC). The results of the analysis showed that, the optimum is 25 C which results to total annual cost (TAC) of , contrary to the TAC of obtained when of 10 C was selected. This achieved financial saving of 27,000 $/year. Furthermore, the minimum hot and cold utilities demands of the unit are and r...

This paper presents the study of the optimal synthesis of energy efficient distillation columns (EEDCs) sequenceby using the driving force method. In order to perform the study and analysis, the EEDCs sequence methodologyhas been developed. Accordingly, the methodology consists of four hierarchical sequential steps; Step 1: ExistingSequence Energy Analysis, Step 2: Optimal Sequence Determination, Step 3: Optimal Sequence Energy Analysis,and Step 4: Energy Comparison. The capability of this methodology has been tested in designing minimumenergy distillation column sequence for hydrocarbon mixture separation process. The results show that themaximum of 39.6 % energy reduction was able to achieve by changing the sequence suggested by the drivingforce method. It can be concluded that, the sequence determined by the driving force method is able to reduceenergy requirement for hydrocarbon mixture separation process. All of this findings show that the methodologyis able to design minimum e...

Distillation is the primary separation process widely used in the industrial chemical process. Although it has many advantages, the main drawback is its large energy requirement, which may significantly influence the overall plant profitability. However, the large energy requirement of these processes can be systematically reduced by using driving force and energy integration methods. This paper presents a methodology for designing energy efficient distillation columns systems based on those two methods. Generally, the proposed methodology consists of four hierarchical steps. In the first step, the system of distillation columns for multicomponent separation is designed based on the conventional distillation column design (shortcut) method. Then, the conventional distillation columns systems design is improved in terms of energy saving by using driving force method in the second step. It is expected in the third step that the distillation columns systems design can be further improv...

Distillation is the primary separation process widely used in the industrial chemical processing. Although it has many advantages, the main drawback is its large energy requirement, which can significantly influence the overall plant profitability. However, the large energy requirement of these processes can be systematically reduced by using driving force and energy integration methods. This paper presents a methodology development for designing energy efficient distillation column systems based on those two methods. Accordingly, the proposed methodology consists of four hierarchical steps. In the first step, the systems of distillation column for multicomponent separation is designed based on the conventional distillation column design method. Then, the conventional distillation columns systems design is improved in terms of energy saving by using driving force method in the second step. It is expected in the third step that the distillation columns systems design can be further improved in terms of energy saving by using energy integration method. Finally, the distillation column systems design is evaluated in in terms of economic performance. By applying the proposed methodology, it is possible to make an early assumption on type of distillation column systems design that is the best in terms of energy saving and cost.

Excessive energy demand in the unit under study leads to high operating cost and suboptimal design. This is because the unit was design using traditional design energy (TDE) methods prior to the advent of pinch technology. Thus, making it imperative to carry out energy assessment of the unit. The aim of this study is to investigate the energy consumption of the unit via pinch analysis. The methodology includes; data extraction from the process flow diagram (PFD) of the unit, selection of initial value of , targeting (energy and cost), determination of (tradeoff between energy and capital cost) and determination of utilities requirement via composite curves (CCs) and grand composite curves (GCC). The results of the analysis showed that, the optimum is 25 o C which results to total annual cost (TAC) of , contrary to the TAC of obtained when of 10 o C was selected. This achieved financial saving of 27,000 $/year. Furthermore, the minimum hot and cold utilities demands of the unit are and respectively. In contrast to the traditional method which requires huge amount of hot and cold utilities of and respectively. Therefore, the pinch method achieved hot and coldutility saving of and respectively, and better cost saving.

This note addresses the problem of identifying the pinch defining streams and the pinch point during grassroots heat exchanger network (HEN) design for problems in which the composite curves are discontinuous. We show that there can exist a logical lower bound on the heat recovery approach temperature (DT min ) for such problems, thereby reducing the range over which targeting needs to be done. Direct application of the Problem Table Algorithm (Linnhoff-March Limited, Knutsford, UK. Process Integration: Part I(a), December 1992) does not determine this lower bound and can also result in the identification of pinch points at which the pinch design rules cannot be directly applied. We present here an example of such a situation and explain how these special cases can be handled.

Waste heat streams are often neglected due to their comparatively low temperatures. However, they can still be utilised by retrofitting existing heat exchanger networks (HEN). Traditionally Pinch Analysis has been used to set heat recovery targets and these can be used as indicators for the retrofit. However, when an existing HEN contains a number of non-optimally placed heat exchangers, major topology modifications may be needed. As a result it may be more economic to achieve heat recovery smaller than the Pinch targets. In some cases exploiting or constructing utility-exchanger heat paths may be too costly and waste heat utilisation for added value side-product should be considered. In this paper the problems in retrofitting a HEN for utilities usage reduction are discussed. Additionally, HEN modification analysis is performed aiming at generating hot water as the value-added product. As the operating conditions vary, the modified network should also be flexible. These issues are ...