Lectures 19 applied heat transfer cm3110 1232019 3 t, outer bulk temperature t, inner bulk temperature l but. With the hi project, you can specify various process and utility stream. Heat exchanger tl heat exchanger for systems with thermal liquid and controlled flows. A heat integration hi project can be used to design multiple heat exchanger networks. The exchange can take place between a process stream and a utility stream cold water, pressurized steam, etc, a process stream and a power source electric heat, or between two process streams resulting in energy integration and reduction of external heat sources. Following figure details the boundary conditions for the heat exchanger.
Nptel chemical engineering process design decisions and. We extend the formulation of the stagessubstages model described in the first part of this series to account for variable heat capacity with temperature, whose influence on heat exchanger network design was not studied. The tutorials are designed to bring the student to a level where he or she can solve problems ranging from basic level to dealing with practical heat. In industrial experience, the calculation of the minimum heating and cooling. Tutorial i composite curves, problem table algorithm and enthalpy intervals pdf unavailable. Pinch technology 2 and mathematical programming 3 have been the two. E1mnl032a design and rating of shell and tube heat. Heat exchangers heat exchangers are used to transfer heat between two sources. With complex dynamic nature, heat exchanger networks hens should be operated successfully throughout the whole time horizon even facing the stochastic and the timevarying disturbances.
An educational software for heat exchanger network design. Tutorial format each tutorial is divided into multiple steps, and each step is presented in its own topic. In the shell of the heat exchanger, air enters at a velocity of 1ms and a temperature of 5c. The following slides present an overview of heat exchangers in supercritical co. Step by step for designing an optimum heat exchanger network. The notes are intended to describe the three types of heat transfer and provide. The costs for the heat exchanger network hen are defined as the sum of the individual hex cost chex. Learn to optimize heat exchanger designs using aspen shell. Phase transitions are possible, for example in evaporators or condensors and some applications involving solids. The heat exchanger layout depends on the heat transfer area hta so an initial estimate is required based on a trial value of the ohtc.
The different modes of heat transfer across the heat exchanger under ideal condition i. Heat transfer processes are classified into three types. Heat exchanger network design, monitoring and optimization. We propose a new strategy to synthesize heat exchanger networks with detailed designs of individual heat exchangers.
This work presents noncommercial software for the design of heat exchanger networks with the pinch method called hint heat integration. Introduction to engineering heat transfer these notes provide an introduction to engineering heat transfer. How to obtain energy targets by the construction of composite curves. At either side of the pinch, the divided heat loads on each stream are combined and then matched according to a systematic procedure derived from simple pinch analysis. Heat exchanger heat recovery pinch point heat exchanger network heat transfer equipment these keywords were added by machine and not by the authors. Mar 01, 2001 then is a heat exchanger network synthesis program that was developed by professor knopf at louisiana state university knopf,1989. Reason for heat exchangers a heat exchanger is a piece of equipment built for efficient heat transfer from one medium to. Introduced a user manual and tutorial of hen, where it integrates the networks of heat exchangers, boilers, condensers and furnaces for best utilization by using. The three rules of the pinch principle by which energy efficient heat exchanger network.
Combining each of these resistances in series gives. Simultaneous synthesis of heat exchanger networks with. The proposed model utilizes a simple principle based on setting the nodes on streams such that to achieve optimization of a heat exchanger network synthesis hens. However, it is not a good choice to find the tradeoff between. Heat exchanger tlma models heat exchange between a moist air network and a thermal liquid network. This step is essential to the network optimisation. Mer network evolution with temperature violationleft and loop. Selection of process, design of flowsheet and materials balance. Finally, we examine the interactions between the hen and the men associated with a distillation network, and show how this novel conceptual framework can be used to design energyefficient distillation networks.
Determine the heat exchanger network above and below the pinch 2. Also, the networks involving heat transfer across the pi. A hydraulic oil system with a thermal control using simscape fluids thermal liquid blocks. It uses pinch technology as the basis for designing a network. During the second stage, heat exchangers are allocated and the practical sequence between the equipment is found, aiming the goals fixed in the first stage. Also remove the heat exchanger from the network using loop breaking and restore the original. Mod05 lec06 tutorial ii heat exchanger network synthesis. Learn to import thermal data of process and utility streams from aspen plus into. Pressure loss generated by the heat exchanger for the primary flow heat transfer between the primary and auxiliary flows. A kepsilon turbulence model is used to analyze both the air and water flow profiles. Heat exchanger network synthesis has been one of the most researched areas within the process industry for. Pinch analysis of heat exchanger networks in the crude.
Heat exchanger network synthesis hens involves the computation of a cost effective network that exchanges heat among a set of process streams, where any heating and cooling not satisfied by exchange among these streams must be provided by external utilities e. Problem table these are the minimum values of heating utility needed at each temperature level. Process design and economic ii semester i heat exchanger networks 1. Processes free fulltext a nodesbased nonstructural. I can say that this work is specific and simple course for designing a. Massheatexchange network representation of distillation. Preparing ansys workbench go to start menuall programssimulationansys 12.
Open aspen energy analyzer verify the units for your simulation through tools preferences variables tab units page. There are various heat exchangers such as shell and tubes heat exchanger, plate heat, and others. Streams are matched and heat exchangers are added until all required heat transfer is accomplished. The same procedure is done below the pinch, except that the criterion is 9. If the flow pattern is more complex such as the case with most shell and tube heat exchangers, then a correction factor term is used and the. Below is a tutorial provided by aspen technology aspen, 2011. Two examples are provided to illustrate this procedure.
The proposed strategy uses a multistep approach by first obtaining a heat exchanger network topology through solving a modified version of the mixed integer nonlinear programming minlp stage. The temperature difference between the fluid and the wall varies along the length of the heat exchanger. Pdf step by step for designing an optimum heat exchanger. Types of heat exchangers doehdbk1018193 heat exchangers. Using mer targets and pinch point determined in prior screencast, setup a heat exchanger network with utilities.
It offers a stepbystep explanation of how an equipment designer would use the standalone program. From the energy point of view, an overall process system can be viewed as three main interactive components see figure 11 that can be integrated into an operable plant aaltola, 2002. Heat exchanger network synthesis with detailed exchanger. Heat exchanger is equipment that deals with transfer of heat between two fluids.
Fluid engine oil sea water inlet temperature, c 65 20 outlet temperature, c 55 25 heat. This work proposes an optimization model for heatexchanger network synthesis that includes a heatexchanger design model. Construct the hot and cold composite curve draw the hot composite curve and leave it fixed draw the cold composite curve in such a way that the smallest. Heat exchanger network hen retrofitting improves heat recovery and. An educational software for heat exchanger network. Equation is used when simple counter or cocurrent flows exist. Tmin throughout the network using a heat flow path. Heat exchanger network design pinch and minimum values. Pinch analysis is a methodology for minimising energy consumption of chemical processes by calculating thermodynamically feasible energy targets or minimum energy consumption and achieving them by optimising heat recovery systems, energy supply methods and process operating conditions. We then employ this framework to provide an interacting heat mass exchanger network representation of a distillation net work. Optimizationbased framework for designing dynamic flexible.
The individual heat transfer coefficients depend on the nature of the heat transfer process, the stream properties and the heat transfer surface arrangements. Energy conservation is important in process design. Design a double pipe heat exchanger with bare inner multitubes that can be used to cool engine oil with cold sea water. Methodologies for designing optimal heat exchanger network hen can be accomplished using pinch analysis or mathematical programming, ravagnani et al.
In some of the examples, we compare the results after making geometry and setup changes. Because heat exchangers come in so many shapes, sizes, makes, and models, they are categorized according to common characteristics. The design manual is the comprehensive reference for htris thermal design recommendations for all types of. It integrates the networks of heat exchangers, boilers, condensers and furnaces for best energy utilization.
Introduction the heat exchanger network hen design method is a. Review of heat exchanger network retrofitting methodologies and. Heat transfer tutorial 1 conduction this is the first of a series of tutorials on basic heat transfer theory plus some elements of advanced theory. Pdf heat exchanger network synthesis and optimisation using. Cctherm is fully integrated with the chemcad suite so process data is automatically. Paper open access related content design and simulation. They range from basic topics that are necessary to write your own codes to some pretty advanced topics regarding details of numerical methods. The heat exchanger network, abbreviated as then, is a hen synthesis program that was developed by knopf et al. Exploring aspen energy analyser to improve processes global. A heat exchanger network obtained using the pinch design method is a network where no heat is transferred from a hot stream whose temperature is above the. Large heat exchangers entail high investment costs. However, it is not a good choice to find the tradeoff between the. One common characteristic that can be used to categorize.
Heat transfer processes set limits to the performance of aerospace components and systems and the subject is one of an enormous range of application. Before designing the heat exchanger network, one needs to know the extent to which heat recovery is economically justified, as well as the kinds. Mathematical programming model for heatexchanger network. Fluid engine oil sea water inlet temperature, c 65 20 outlet temperature, c 55 25 heat load, kw 117. Heat integration pinch technology freeware educational software heat exchanger network retro. It is also known as process integration, heat integration, energy integration or pinch technology. Process design decisions and project economics by dr. Hydraulic design and heat transfer in supercritical fluids. Most of papers published in literature present the heat exchanger network synthesis without taking into account dt min optimisation. Heat exchanger network hen, cost estimation, optimum hen. Most solvers laminar flow, turbulence, heat transfer are illustrated with at least one. In this case, the steam is hot fluid and air is acts as a cold fluid. To develop simulation model for heat exchanger network, single heat exchanger simulation model is developed by using energy balance equations and effectivenessntu method.
Particularly in this design analysis extreme ambient temperature in winters is 28 oc. For a new process, the following process streams must be cooled or heated stream mcp btuhf temperature in f temperature out f 1 2 400 300 2 4 300 100 3 3 90 320 4 2 170 320 the minimum approach temperature is 10f. Then uses pinch analysis for the optimum design of heat exchanger network. Stagewise superstructure of a heat exchanger network hen with two hot and three cold process streams. Heat exchanger network synthesis hens is an important part in the overall chemical process. Unit 571 new smyrna beach, fl 32128 386882ezce3923. Heat exchanger g heat exchanger for systems with gas and controlled flows.
Aspen energy analyzer, heat exchange, pinch analysis, fi2epi, xylitol proces. Heat exchanger network hen is an important technique for maximizing heat. Pressure drop and heat transfer in tubeintube helical heat exchanger under turbulent condition was studied by vimal kumar et al. In this tutorial, there are no ecus considered so the following is used to calculate the total investment costs c inv. Selection of process, design of flowsheet and materials. Pdf global optimization of heat exchanger networks. Use aspen energy analyzer aea to design heat exchanger networks hens. Then is a heat exchanger network synthesis program that was developed by professor knopf at louisiana state university knopf,1989. Heat exchangers 73 individual thermal resistances of the system. The first is conduction, which is defined as transfer of heat occurring through intervening matter without bulk motion of the matter. Therefore, a nodesbased nonstructural model considering a series structure nnm is proposed. Learn cfd from fudamentals to advanced topics using our toolbox here you can find the comprehensive list of tutorials. The use of pinch analysis as a tool for designing optimal heat exchanger networks is.
At the end of the streams a utility heat exchanger may be placed to ensure the desired target temperatures to get reached. Heat integration strategies have been developed to reduce both, capital and operating costs since decades by now. The aim of heat exchanger network synthesis is to design a costeffective network configuration with the maximum energy recovery. Sep, 2020 the accuracy of the solutions and the required computational costs show that the model is well suited for solving heat exchanger network synthesis problems combined with detailed exchanger designs, which is demonstrated in part 2 of the paper. A heat exchanger network obtained using the pinch design method is a network where no heat is transferred from a hot stream. In each stage of the superstructure each hot stream is possibly connected with each cold stream. A solid a block of metal, say has one surface at a high.
Exchanger, the heat exchanger ceases and it would damage the heat exchanger also. Heat exchanger tltl heat exchanger for systems with two thermal liquid flows. Variable heat capacity cp frequently arises when streams of high molecular weight are used, or when temperature ranges are large, such as in petroleum fractionation, where. This process is experimental and the keywords may be updated as the learning algorithm improves. Costoptimal heat exchanger network synthesis based on a. Many difficulties will be alleviated if models were available to compute.
In heat transfer calculation the basic assumption is that heat lost by steam in heating section is used to increase the temperature of process fluid in the same section. Nptel chemical engineering process design decisions. The proposed model utilizes a simple principle based on setting the nodes on streams such that to achieve optimization of a heat exchanger network synthesis hens problem. Tminis the pinch the nonoverlap on the right is the minimum heating utility and the nonoverlap on the left is the minimum cooling utility. In current studies, overdesigning hens is a commonly adopted strategy to deal with the stochastic disturbances and also the flexible design. The interface of the program has been designed focusing on getting a. Heat exchanger geometries are generally complex and cannot be included in the cfd domain due to widely varying spatial length scales. Designing a heat exchangers network hen by application of pinch analysis is an effective technique for energy integration. In order to reduce capital cost, in practice a minimum temperature difference. The following slides present an overview of heat exchangers in supercritical co 2 applications introduction to sco 2 heat exchangers in sco2 cycle applications heat exchanger mechanical design for sco 2 hydraulic design and heat transfer in supercritical fluids 0 200 400 600 800 1200 0 20 40 60 80 100 120 140 c 0 20,000 40,000 60,000.
Pinch technology for heat exchanger network design. Each tutorial features a different application type often solved with autodesk simulation cfd. General 474 2 also batch heat exchangers are widely used. Heat exchanger network an overview sciencedirect topics. Here, we are designing the steam coil for air cooled heat exchanger, for heating the process fluid. The hydraulic oil system consists of an oil storage tank represented by the tank tl block with two inlets, a pump represented by a mass flow rate source tl block, and pipelines represented by pipe tl block. Previously published results have used heat exchangers that have been sized for a placement at a specific location in a heat exchanger network, thereby aiming to provide the lowest cost solution. The ultimate aim of this report is to design an air cooled heat exchanger, preferably of shell and tube type, that can be used to transfer the heat energy generated in the windings of 3phase induction motor working at 800 rpm assumed. It is possible to estimate the heat exchanger area and capital cost, and hence the optimal. The entire network, both above and below the pinch, can then be represented on one diagram. The research presented here shows that equally good or better solutions can be obtained by using standard, modular sizes of the heat exchangers. Tutorial ii heat exchanger network synthesis using pinch technology pdf unavailable.
519 383 902 865 1347 1035 1281 565 112 710 428 794 200 1630 1507 1409 1772 1342 487 1757 967 720 1748 484 1028 1269 1318 1445 1240 956 580 491 1666 1075 1679 1536