Heat Exchanger Network Design

Pinch technology is one of the most powerful methodologies of process integration that allows industries to increase their profitability through reductions in energy, water and raw materials consumption. In this study, reduction in the total annual cost of heat exchanger network (HEN) of Fluid Catalytic Cracking (FCC) unit in Kaduna Refining and Petrochemical Company (KRPC), Kaduna was determined. With the help of pinch technology, the reduction was achieved by first determining optimum minimum temperature difference by trading off energy cost and capital cost targets as a function of minimum temperature difference. Thereafter, the total annual cost obtained at the optimum minimum temperature difference was compared with total annual cost of existing design. The results of the analysis showed that the optimum minimum temperature difference was 12℃, the total annual costs of the existing design and the optimum-minimum-temperature-difference based cost were $8.7 and $7.1 Million respectively. This amounted to percentage reduction in the total annual cost of 18.4% which means that about $1.6 Million would been saved annually using the optimum minimum temperature difference to design the HEN of the FCC unit.

Pinch technology is one of the most powerful methodologies of process integration that allows industries to increase their profitability through reductions in energy, water and raw materials consumption. In this study, reduction in the total annual cost of heat exchanger network (HEN) of Fluid Catalytic Cracking (FCC) unit in Kaduna Refining and Petrochemical Company (KRPC), Kaduna was determined. With the help of pinch technology, the reduction was achieved by first determining optimum minimum temperature difference by trading off energy cost and capital cost targets as a function of minimum temperature difference. Thereafter, the total annual cost obtained at the optimum minimum temperature difference was compared with total annual cost of existing design. The results of the analysis showed that the optimum minimum temperature difference was 12℃, the total annual costs of the existing design and the optimum-minimum-temperature-difference based cost were $8.7 and $7.1 Million respectively. This amounted to percentage reduction in the total annual cost of 18.4% which means that about $1.6 Million would been saved annually using the optimum minimum temperature difference to design the HEN of the FCC unit.

Pinch technology is one of the most powerful methodologies of process integration that allows industries to increase their profitability through reductions in energy, water and raw materials consumption. In this study, reduction in the total annual cost of heat exchanger network (HEN) of Fluid Catalytic Cracking (FCC) unit in Kaduna Refining and Petrochemical Company (KRPC), Kaduna was determined. With the help of pinch technology, the reduction was achieved by first determining optimum minimum temperature difference by trading off energy cost and capital cost targets as a function of minimum temperature difference. Thereafter, the total annual cost obtained at the optimum minimum temperature difference was compared with total annual cost of existing design. The results of the analysis showed that the optimum minimum temperature difference was 12℃, the total annual costs of the existing design and the optimum-minimum-temperature-difference based cost were $8.7 and $7.1 Million respe...

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 heat exchanger network (HEN) of the unit of benzene production at petrochemical plant was inspected and the obtained data were analyzed for possible plant retrofit targeting the minimal energy consumption and increasing of plant efficiency. The benzene-toluene-xylene fractionation, hydrogenation, hydrodesulphurization and hydrothermo processing units of the plant were analysed and the data of existing HEN flowsheets were extracted. The minimum temperature difference for the retrofit was determined by analyzing the cost parameters of the proposed modifications as well as the energy cost. Using Pinch Analysis methodology the Composite Curves and Grid Diagram were obtained for the integrated processes of these plant units. The new flowsheet of the HEN of the regarded units was developed; and the possible application of heat transfer equipment was analyzed and proposed.

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.

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.

Now days, All new device applications in oil refinement, chemical, petro-chemical, and power generation area unit accommodated through the utilization of typical shell and tube sort heat exchangers. The elemental basis transfer necessities. However, there are a unit limitations related to the technology that embrace inefficient usage of shell facet pressure drop, dead or low flow zones round the baffles wherever fouling and corrosion will occur, and flow evoked tube vibration, which may ultimately lead to breakdown. We would like to presents a recent innovation and development of a brand new technology, referred to as Twisted Tube technology, which has been able to overcome the limitations of the traditional technology. This analysis compares the development, performance, and economic science of Twisted Tube exchangers against typical styles for copper materials as well as reactive metals for this datum is shell and tube technology is a price effective, tried resolution for a good t...

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...

This article describes a study in which the various stagewise and interval-based superstructures for the mixed integer non-linear programming (MINLP) optimisation of heat exchanger networks were systematically compared, using exactly the same basis. The effect of using different logarithmic mean temperature difference (LMTD) approximations on the Total Annual Cost of the network and the network structure were examined. The accuracy of the approximations was also analyzed over a wide range of temperature difference ratios. It is concluded that the best approximation, which is the Underwood-Chen approximation, should be used in future mathematical optimisation of Heat Exchanger Network Synthesis problems.

This study makes use of a novel methodology for the synthesis of heat exchanger networks, which is aimed at overcoming the shortcomings associated with the use of shortcut models to represent individual exchangers in the synthesis network. The new approach entails the use of a number of correction factors to get networks which are based on the use of shortcut models, such as the mixed integer non-linear programming (MINLP) stage-wise superstructure (SWS) of Yee and Grossmann (1990) to more closely represent physically achievable heat exchangers and ensure that the MINLP network topology optimisation step of these models converge on a real design, rather than an approximated one. In this paper, the SWS formulation is used for the generation of an initial network after which its objective function is modified to include the correction factors that force its objective function towards the cost of a network whose individual exchangers are designed using methods such as Bell-Delaware and heuristics. The modified objective function includes parameters that modify the areas obtained by the shortcut based MINLP model so as to more closely represent the areas obtained by the detailed models and also includes a novel method for including the number of shells required for each exchanger duty. The correction factors account for pressure drops, F t correction factors, number of shells, TEMA considerations, and changes to the overall heat transfer coefficient of each stream match. The methodology is applied to two examples and the solutions are comparable with other solutions obtained in literature and were shown to produce good solutions. The reason that the method is effective is because many potential networks are evaluated during the iterative procedure and the best network, based on the detailed exchanger designs, is chosen. In this way it is possible to use the detailed exchanger designs to "guide" the MINLP optimisation towards more realistic networks and also to generate many different potential networks.

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...

Climate change is increasing as an effect of human activities around the world. The reduction of CO2 emissions by human activities would be the most important measure to reduce this negative effect. Recently, many countries around the world have committed to reduce his CO2 emissions over time. In this context, the world has been struggling to balance the growth in energy requirement and environment conservation for a sustainable future, mainly due the adverse environmental, social and economic impacts of global warming that are associated with greenhouse gas emissions. In the last decade, some methodologies based on Pinch Analysis (Linnhoff et al., 1982) were developed as a tool for carbon emission reductions and planning. Thus, the concepts of Pinch Analysis were applied to solve carbon transfer, maximum carbon recovery, minimum carbon targets and the design of carbon exchange networks. Focusing in planning for the power generation sector, a new methodology is presented based in th...

This paper presents a simple methodology for cost estimation of a near optimal heat exchanger network, which comprises mixed materials of construction. In traditional pinch technology and mathematical programming it is usually assumed that all heat exchangers in a network obey a single cost model. This implies that all heat exchangers in a network are of the same type and use the same materials of construction (an assumption that is unwarranted). The method introduced in this article enables the designer to decomposes the total cost of a heat exchanger into two elements, namely cost of the tubes and cost of the shell, thereby predict a more reliable cost for the network. By subsequent use of the binary variables and evaluation of the physical conditions of the streams, one can assign the streams to pass either through shell or tubes. Whereby, shell and tubes can be of different materials and therefore different cost models can be applied. Another advantage of the approach is that the pressure drop in each side of the exchanger (shell or tubes) can be assessed leading to more accurate evaluation of corresponding heat transfer coefficient for each individual stream. Finally an objective function (total cost) can be defined based on mixed materials of construction and different values of heat transfer coefficients. The proposed model has been utilized in three different case studies and the results are compared with those of a commercially available software (SUPERTARGET). The comparison shows reductions of more than 17% and 14% in total annual costs in the two cases, and 2.5% reduction in third, confirming the fact that more accurate evaluation of heat transfer coefficient for each individual stream can lead to better network design.

The specification design of this heat exchanger has been taken from a real project executed by Clough. The process data given matches the real application exactly and was used to design the heat exchanger. The Regeneration Gas Heater was manufactured in Malaysia, and was shipped to a fabrication yard in Thailand for installation within a pre-assembled module. This paper illustrates fully thermal and mechanical design for this heat exchanger. Here, the redesign takes place to improve the design by reselect different parameters which can enhance the heat transfer through the exchanger. As well as, new correlation is developed to predict Nusselt number for tube side which reduces the error percent with Kern's method from 15.25% to 12.64% based on simulation data. Where, the proposed and Kern's correlations compared against experimental data to show that the proposed correlation is quite accurate. After many iterations, the new design suggested that four tubes passes need to be used with 1.38 m tube length. In addition, the tube arrangement chosen to be square type with 0.9 m shell diameter. With these parameters, the exchanger achieves high enough heat transfer coefficient and the pressure drop within specification.

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...

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.

A shell and tube heat exchanger (ST) is analyzed numerically and experimentally using various configurations of baffles. The baffles used are segmental baffle (SB) with baffle cut of 30 0 (SB-30), 50 0 (SB-50), Align baffle with baffle cut of 30 0 (AB-30) and 50 0 (AB-50). The numerical study of ST with different configurations shows that AB-30 has superior effectiveness than other configurations. The comparison of numerical and experimental results of AB-30 shows a deviation of 10.1%. The study also includes a comparison of the segmental baffle (STs) with continuous helical baffles with a helix angle of 25 0 (STc) experimentally. The comparative analysis, drawn between STs and STc shows that STs have better effectiveness at all considered mass flow rates varied between 0.00005 to 0.00018 m 3 /s. Lower mass flow rate had shown better effectiveness than STs by 27.7%. The fixed helix angle of 25°was provided to helical baffles, results in increased heat transfer coefficient (HTC) at the lower pressure drop. The flow pattern in the shell for both STs and STc maintained forced helical and rotational due to the geometry pattern of the baffles, respectively. Based on the experimental data, the non-dimensional parameters for HTC and pressure drop (ΔP o) is calculated for both the configurations. However, for the optimal design of the heat exchanger, the maximum heat recovery rate has also been computed using the composite hot and cold diagram for different configurations.

Now days, All new device applications in oil refinement, chemical, petro-chemical, and power generation area unit accommodated through the utilization of typical shell and tube sort heat exchangers. The elemental basis transfer necessities. However, there are a unit limitations related to the technology that embrace inefficient usage of shell facet pressure drop, dead or low flow zones round the baffles wherever fouling and corrosion will occur, and flow evoked tube vibration, which may ultimately lead to breakdown. We would like to presents a recent innovation and development of a brand new technology, referred to as Twisted Tube technology, which has been able to overcome the limitations of the traditional technology. This analysis compares the development, performance, and economic science of Twisted Tube exchangers against typical styles for copper materials as well as reactive metals for this datum is shell and tube technology is a price effective, tried resolution for a good t...

A shell and tube heat exchanger (ST) is analyzed numerically and experimentally using various configurations of baffles. The baffles used are segmental baffle (SB) with baffle cut of 30 0 (SB-30), 50 0 (SB-50), Align baffle with baffle cut of 30 0 (AB-30) and 50 0 (AB-50). The numerical study of ST with different configurations shows that AB-30 has superior effectiveness than other configurations. The comparison of numerical and experimental results of AB-30 shows a deviation of 10.1%. The study also includes a comparison of the segmental baffle (STs) with continuous helical baffles with a helix angle of 25 0 (STc) experimentally. The comparative analysis, drawn between STs and STc shows that STs have better effectiveness at all considered mass flow rates varied between 0.00005 to 0.00018 m 3 /s. Lower mass flow rate had shown better effectiveness than STs by 27.7%. The fixed helix angle of 25°was provided to helical baffles, results in increased heat transfer coefficient (HTC) at the lower pressure drop. The flow pattern in the shell for both STs and STc maintained forced helical and rotational due to the geometry pattern of the baffles, respectively. Based on the experimental data, the non-dimensional parameters for HTC and pressure drop (ΔP o) is calculated for both the configurations. However, for the optimal design of the heat exchanger, the maximum heat recovery rate has also been computed using the composite hot and cold diagram for different configurations.

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.

An experimental investigation on comparative heat transfer study on a solvent and solution were made using 1-1 Shell and Tube Heat Exchanger. Steam is the hot fluid, whereas Water and Acetic acid-Water miscible solution serves as cold fluid. A series of runs were made between steam and water, steam and Acetic acid solution. In addition to, the volume fraction of Acetic acid was varied and the experiment was held. The flow rate of the cold fluid is maintained from 120 to 720 lph and the volume fraction of Acetic acid is varied from 10-50%. Experimental results such as exchanger effectiveness, overall heat transfer coefficients were calculated. A mathematical model was developed for the outlet temperatures of both the Shell and Tube side fluids and was simulated using MATLAB program. The model was compared with the experimental findings and found to be valid.

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 requirement of energy in any processing industry is not only a need but it is indeed a most wanted utility. In a typical processing or manufacturing industry the most common utility are steam and cooling water. However the cost of these utility are no longer cheap, in fact they are expensive. Therefore saving these utility or minimizing the usage of these utilities is one of the most needed practice in a processing industry. Pinch technology is the most common method, which is aimed at minimizing the requirement of utilities by maximizing the process to process heat transfer. In the present study temperature interval diagram or TID is used to identify the targets for minimum utility requirement and maximum process to process heat transfer in a processing facility. The targets for heat exchanger network are presented and minimization of number of heat exchangers are provided using stream splitting technique.

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.

A dehydration unit using triethylene glycol absorption is a common process in natural gas processing. In its regeneration section, the regenerated lean glycol needs to be cooled before entering the glycol absorber, while the rich glycol is to be preheated before entering the regenerator. This is a good candidate for heat exchanger network (HEN) optimization. In this work, the HEN was revisited using pinch analysis (PA) and mathematical programming (MP) using superstructure. The optimized networks were evaluated using simplified total annual cost (TAC). The PA method using small Tmin (minimum temperature approach) led to the configuration of three exchangers, a heater and a cooler, with minimized utilities. At larger Tmin, the configuration became into two exchangers, two heaters, and a cooler. The minimum calculated TAC is $60,351/year at Tmin = 12.5 o C. Furthermore, it was revealed that one heater and one exchanger were two small. Therefore, they were omitted, and the heat load were redistributed to the network. The calculated TAC became $59,224/year. The superstructure approach resulted in two exchangers, a heater, and a cooler; with a calculated minimum TAC of $57,597/year. The two approaches have resulted in very similar minimized TAC.

A dehydration unit using triethylene glycol absorption is a common process in natural gas processing. In its regeneration section, the regenerated lean glycol needs to be cooled before entering the glycol absorber, while the rich glycol is to be preheated before entering the regenerator. This is a good candidate for heat exchanger network (HEN) optimization. In this work, the HEN was revisited using pinch analysis (PA) and mathematical programming (MP) using superstructure. The optimized networks were evaluated using simplified total annual cost (TAC). The PA method using small Tmin (minimum temperature approach) led to the configuration of three exchangers, a heater and a cooler, with minimized utilities. At larger Tmin, the configuration became into two exchangers, two heaters, and a cooler. The minimum calculated TAC is $60,351/year at Tmin = 12.5 o C. Furthermore, it was revealed that one heater and one exchanger were two small. Therefore, they were omitted, and the heat load were redistributed to the network. The calculated TAC became $59,224/year. The superstructure approach resulted in two exchangers, a heater, and a cooler; with a calculated minimum TAC of $57,597/year. The two approaches have resulted in very similar minimized TAC.

Process and manufacturing industries today are under pressure to deliver high quality outputs at lowest cost. The need for industry is therefore to implement cost savings measures immediately, in order to remain competitive. Organizations are making strenuous efforts to conserve energy and explore alternatives. This paper explores the development of an intelligent system to identify the degradation of heat exchanger system and to improve the energy performance through online monitoring system. The various stages adopted to achieve energy performance assessment are through experimentation, design of experiments and online monitoring system. Experiments are conducted as per full factorial design of experiments and the results are used to develop artificial neural network models. The predictive models are used to predict the overall heat transfer coefficient of clean/design heat exchanger. Fouled/real system value is computed with online measured data. Overall heat transfer coefficient of clean/design system is compared with the fouled/real system and reported. It is found that neural net work model trained with particle swarm optimization technique performs better comparable to other developed neural network models. The developed model is used to assess the performance of heat exchanger with the real/fouled system. The performance degradation is expressed using fouling factor, which is derived from the overall heat transfer coefficient of design system and real system. It supports the system to improve the performance by asset utilization, energy efficient and cost reduction in terms of production loss. This proposed online energy performance system is implemented into the real system and the adoptability is validated.

In present day shell and tube heat exchanger is the most common type heat exchanger widely used in oil refinery and other large chemical process, because it suits high pressure application. The process in solving simulation consists of modelling and meshing the basic geometry of shell and tube heat exchanger using CFD package ANSYS 12.0. The objective of the project is design of shell and tube heat exchanger with helical baffle using catia software and study the flow and temperature field inside the shell using ANSYS software tools. The heat exchanger contains 27 tubes and 5490 mm length shell diameter 540 mm. The helix angle of helical baffle will be varied from 0 to 200 degree. In simulation, we will show how the temperature and heat flux vary throughout the surface of the condenser. The flow pattern in the shell side of the heat exchanger with continuous helical baffles was forced to be rotational and helical due to the geometry of the continuous helical baffles, which results in...

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.

The main aim of this work is to check the bio fouling in cooling tower and its effect on power generation. The way to reduce bio fouling is necessary issue within the thermal power station, as it results in reduction of the heat transfer rate and ultimately reduction in the power generation rate of plant. So as to attenuate the energy consumption in process plant equipped with device network. In various branches of chemical industries fouling builds up on heat transfer surfaces is a heat transfer equipment burning extra fuel to compensate for a reduced heat recovery accepting reduction of plant output due to periodic equipment cleaning and recovering the cost of cleaning interventions. Microbiological fouling can cause energy losses and loss of tower efficiency. The pilot plant is very useful in the thermal power plant to test the cooling water and then it is used in the thermal power plant to reduce the losses due to the bio fouling. In large power plant they having pilot plant wit...

Pinch technology is developing and its application is widening, reaching new horizons. The original concepts of pinch approach were quite clear and, because of numerous ways, application engineer gets confused among these numerous flexibilities. Therefore, there is a need for a rigorous and robust model which could guide the optimisation engineer on deciding the applicability of the pinch approach and direct sequential step of procedure in predefined workflow, so that the precision of approach is ensured. Exploring the various options of a novice handson algorithm development that can be coded and interfaced with GUI and keeping in mind the difficulties faced by designers, an effort was made to formulate a new algorithm for the optimisation activity. As such, the work aims at easing out application hurdles and providing hands-on information to the developer for use during preparation of new application tools. This paper presents a new algorithm, the application which ensures the designer does not violate basic pinch rules. To achieve this, intermittent check gates are provided in the algorithm, which eliminate violation of predefined basic pinch rules, design philosophy, and Engineering Standards and ensure that constraints are adequately considered. On the other side, its sequential instruction to develop the pinch analysis and reiteration promises maximum energy recovery (MER).

The need to develop new and improved ways of reducing energy use and increasing energy intensity in industrial processes is currently a major issue in New Zealand. Little attention has been given to optimisation of noncontinuous processes in the past, due to their complexity, yet they remain an essential and often energy intensive component of many industrial sites. Novel models based on pinch analysis that aid in minimising utility usage have been constructed here through the adaptation of proven continuous techniques. The knowledge has been integrated into a user friendly software package, and allows the optimisation of processes under variable operating rates and batch conditions. An example problem demonstrates the improvements in energy use that can be gained when using these techniques to analyse non-continuous data. A comparison with results achieved using a pseudo-continuous method show that the method described can provide simultaneous reductions in capital and operating costs.

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...

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.

The tertiary-building sector is one of the most important energy consumers in the Morocco, especially thermal energy. Its intensive use of energy is highly related to the building’s inefficient processes. The Moroccan strategy for energy efficiency aims mainly to save 12% of energy consumption by 2020 and 15% by 2030, which reinforce the appearance of many energy saving alternatives ranging from sensitization and construction laws to engineering applications. The present paper addresses the problem of the building complex energy efficiency in order to improve its performance thermally. The proposed approach in this work is based on the pinch technology which is a technique widely used to integrate and optimize the energy of thermal systems and which has demonstrated its successfulness for industrial process. The simulation results reveals that the potential thermal energy saving reaches 21.16%, with heat exchange network design initially proposed to clearly show the potential recove...

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...

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...

Developing a flexible heat exchanger network, that will remain operable in the face of potential variations in stream parameters, or variables, around some nominal values, especially for large problems, are difficult to solve simultaneously. A hybrid synthesis approach that systematically combines sequential and mathematical programming techniques may be more suitable to adopt. The proposed method presented in this paper entails firstly generating two representative single period networks using the Pinch Technology Stream Temperature versus Enthalpy Plot (STEP) approach and the multi-period stage-wise superstructure model for heat exchanger network synthesis. Streams for the representative network are obtained using the largest stream heat demand as criteria. The second stage of the proposed method entails generating a reduced multi-period stage-wise superstructure, using a combination of the matches obtained in the single period representative networks of the first step as initiali...

Inter-plant integration via a heat recovery loop (HRL) is an economic method for increasing total site process energy efficiency of semi-continuous processes. Results show that both the constant storage temperature approach and variable storage temperature approach have merit. Depending on the mix of source and sink streams attached, it may be advantageous to change the operation of an existing HRL from a constant temperature storage to a variable temperature storage. To realise the full benefits of this change in operation, a redistribution of the existing heat exchanger area may be needed.

Heat integration by means of Heat Exchanger Network (HEN) synthesis is fundamental in Process Engineering. There are aspects and design options that so far have been scarcely explored in this area. That is the case of heat and work integration. Recent literature shows that the simultaneous optimization of HEN with pressure recovery units can yield substantial gains. Superstructure based mathematical models for HEN synthesis are usually extended for dealing with heat and work integration formulations. Those models are complex to solve, containing nonlinearities and non-convexities that need to be overcome with simplifying assumptions (e.g., isothermal mixing after stream splitting or limiting the structural possibilities) and efficient solution approaches. An important trend in the heat integration literature is the use of meta-heuristic methods. These have arisen as an interesting alternative to the deterministic approaches. Meta-heuristics are attractive since they do not require a...