L'échangeur gaz-gaz en matériau polymère, développé conjointement par la Société d'Équipements Thermiques et de Récupérateurs Métalliques (SETREM) et l'Institut Français du Pétrole (IFP), fait ici l'objet d'une description de son principe de base et des méthodes de modélisation développées par I'IFP. Le caractère modulaire de sa conception et les avantages spécifiques des matériaux polymères (inertie chimique, mise en oeuvre aisée, non adhérence des salissures, légèreté) constituent les principaux arguments des développements potentiels de cet échangeur. Parmi ceux-ci figure la récupération sur fumées de chaudière alimentée en fuel lourd n°2 dont l'intérêt a été démontré sur un prototype essayé au Centre d'Études et de Développement Industriels de I'IFP. Il est également fait état de la première application effective de cet échangeur pour la déshumidification des fumées issues de chaudières à gaz à condensation. On évite ainsi le tubage des conduits de fumées qui constitue un obstacle économique majeur à la diffusion de telles installations en chauffage collectif. Sont présentées enfin les caractéristiques d'un échangeur de ce type (surface d'échange : environ 5000 m²) assurant le séchage d'air humide dans une application du secteur agroalimentaire en cours de projet. The gas-gas heat exchanger made of polymer material, developed jointly by Société d'Equipements Thermiques et de Récupérateurs Métalliques (SETREM) and the Institut Français du Pétrole, (IFP), is described here in its basic principle together with the modeling methods developed by IFP. The modular nature of its design and the specific advantages of polymer materials (chemical inertia, ease of implementation, nonadherence of fouling, lightness) make up the principal arguments for the potential development of this heat exchanger. Among these arguments is heat recovery from the flue gas from a furnace fired by No. 2 heavy fuel oil, for which the advantage has been demonstrated with a prototype tested a the IFP Centre d'Etudes et de Développement Industriels. Mention is also made of the first effective application of this heat exchanger for the dehumidification of flue gas issuing from condensation gas furnaces. The installation of linings in flues can thus be avoided, because this is one of the major economic obstacles in the way of the widespread use of such installations for apartment-block heating. The article ends with a description of the characteristics of a heat exchanger of this type (heat-exchange surface = about 5000m²) for use in drying the damp air in an application that is being planned in the agri-food business.

Cet article porte sur la mise au point d'une méthode d'optimisation du système de production d'utilités d'un ensemble industriel et l'étude de dispositifs destinés à économiser l'énergie. Le programme d'optimisation fait appel à la programmation linéaire. Un programme générateur de matrice et un programme de traduction des résultats ont été mis au point. On dispose ainsi d'un programme d'optimisation adapté à tout système de production d'utilités. Différents dispositifs permettant d'économiser l'énergie ont été étudiés. L'étude a porté, d'une part, sur des dispositifs classiques tels que les dispositifs de récupération de chaleur sur les fumées et, d'autre part, sur des dispositifs nouveaux. Des solutions nouvelles ont été recherchées dans deux domaines qui sont apparus essentiels : production combinée de travail et de chaleur et valorisation de calories à bas niveau. Enfin la méthode d'optimisation a été appliquée au cas d'une raffinerie réelle dont l'étude avait été effectuée récemment. L'optimisation sur une base économique a permis de dégager une économie de 9,3 % sur la consommation d'énergie, mais a surtout démontré les larges possibilités de la méthode dans son application à un cas concret. This article describes the development of a method for optimizing utilities production systems for on industrial installation and the study of energy-saving systems. The optimization program makes use of linear programming. A matrix-generating program and a result-translating program were developed. The result is an optimization program suited for any utilities production system. Different energy-saving systems were examined, including conventional systems such as heat-recovery devices as well as new systems. New solutions were sought for in two fields which appear essential, i. e. the combined production of work and heat and the valorization of low-level calories. The optimization method was applied to the case of an actual refinery on which a study had recently been carried out. Optimization on on economic basis revealed a 9,3 % saving in energy consumption as well as, and in particular, the extensive possibilities of the method in its application to a concrete case.

La mise en oeuvre à la fois de cycles thermodynamiques et de fluides adaptés permet d'élargir considérablement les possibilités de récupération et de valorisation de la chaleur à bas niveau contenue dans les rejets thermiques industriels, l'eau géothermale, le rayonnement solaire ou le milieu environnant. Ceci permettra une meilleure préservation des ressources énergétiques dans les principaux secteurs consommateurs d'énergie : résidentiel, tertiaire et industriel. On décrit les possibilités que présentent : - Les cycles thermodynamiques directs (pompes de chaleur à compression ou à absorption) dans le domaine du chauffage résidentiel et tertiaire où elles sont déjà bien implantées et dont les applications commencent à pénétrer le secteur industriel. - Les cycles thermodynamiques inverses (thermotransformateurs et cycles moteurs à fluide organique) pour lesquels les progrès techniques accomplis et l'accroissement du prix de l'énergie devraient permettre d'en assurer la diffusion progressive dans le secteur industriel. The implementation of both thermodynamic cycles and suitable fluids makes for a considerable widening of the capacity to recover and upgrade the low-level heat contained in industrial heat wastes, geothermal water, solar radiation or the surrounding environment. This will make for better conservation of energy resources in the leading sectors of energy consumption, i. e. residential, tertiary and industrial. This article describes these possibilities in the form of: (a) Direct thermodynamic cycles (compression or absorption heat pumps) in the field of home and tertiary heating where they have already obtained a solid foothold and for which applications are beginning te penetrate into the industrial sector. (b) Reverse thermodynamic cycles (heat transformers and organic-fluid motor cycles) for which the technical advances made and the increase in energy prices should enable them to spread progressively throughout the industrial sector.

Un accroissement important de la demande de gaz naturel est prévu dans les années à venir. En Europe, cet accroissement de la demande ne va pas pouvoir être entièrement couvert par les sources d'approvisionnement actuelles et il sera de plus en plus nécessaire de faire appel à de nouveaux fournisseurs. Le recours à ces nouvelles sources d'approvisionnement va exiger des investissements considérables et devrait se traduire par une progression des coûts. Des progrès techniques sont nécessaires pour réduire les coûts tout en assurant la protection de l'environnement et une sécurité accrue. Le recours à des solutions innovantes dans les domaines de la production, du traitement, du transport et de la conversion chimique devrait dans l'avenir élargir les options et les débouchés offerts à l'exploitant. A considerable increase in natural gas demand has been forecast for the coming years. Present-day supply sources will be unable to cover the growing demand in Europe and new suppliers will need to be called on more and more. Diversifying to new supply sources will entail heavy investments and is bound to mean rising costs. Technical progress is necessary to reduce costs, while protecting the environment and providing improved safety conditions. Innovative solutions in the areas of production, processing, transportation and chemical conversion should in the future widen the options and outlets available to operators.

Cet article présente une méthode d'optimisation des procédés de séparation basée sur une analyse thermodynamique. Cette analyse s'appuie sur un bilan exergétique qui est établi dans le cas général d'un système quelconque opérant en régime permanent. Les facteurs qui conditionnent le rendement exergétique d'un procédé de séparation sont ensuite examinés. Il en résulte une méthode d'optimisation basée sur une réduction des irréversibilités thermodynamiques. Des exemples concrets d'application en raffinage et en traitement de gaz naturel sont présentés, et on montre comment cette analyse peut déboucher sur la conception de procédés innovants. The optimization of separation units in refining and natural-gas processing must take into consideration new needs and constraints that may seem incompatible. New installations must be designed not only on the basis of energy optimization but also by seeking to minimize investments and to respect new rules concerning environmental protection. The optimization described in this article is based on a thermodynamic analysis of different material and energy exchanges, The energybalance provides a suitable basis for making this analysis. It leads to the defining of an exergy efficiency that is all the higher as the thermodynamic irreversibilities are reduced, and that tends toward one for an ideal reversible system. For a separation process, a separation exergyterm is defined that correspond to the minimum separation work . Distillation is the basic separation operation. The exergy efficiency of this operation is low, and we show that, even in a relatively favorable cas, it is no greater than a value of about 6%. For an atmospheric distillation operation of crude oil, the exergy efficiency is about 4%. This overall exergy efficiency is the product of an external exergy efficiency and an internal exergy efficiency. The external exergy efficiency can be improved by better thermal integration among the units or by using cogeneration for supplying heat to the reboiler. Another possibility, that is sometimes used for superfractionation, consists in providing the heat required by the reboiler by overhead steam condensation after recompression. The internal exergy efficiency depends on the number and arrangement of the plates as well as on the composition of the mixture. In particular, it is found that separation by distillation of a component present in low concentration is very inefficient. The use of a separation agent -solvent or adsorbent - serves to separate a constituent that cannot be separated directly by distillation under satisfactory conditions. The separation process is optimized in this case by applying a procedure similar to the one followed for distillation. The integration of several functions in the same piece of equipment or of several transformation steps in the same process often reduces both the energy expenditures and the investments required. Several examples are developed in the text - case of an exchanger-dephlegmator, reactive distillation and absorption, integrated process for treating natural gas. These examples show how a thermodynamic analysis aiming to reduce irreversibilities leads to the designing of innovating processes.

Les échangeurs gaz-liquide et gaz-gaz respectivement développés par la Société Nationale Elf Aquitaine (SNEA) et l'institut Français du Pétrole (IFP) dans le cadre d'un contrat AFME d'aide à l'innovation permettent, grâce au recours à des matériaux plastiques, de s'affranchir du seuil de condensation sulfurique, 180°C, en deçà duquel apparaissent les problèmes de corrosion sur les récupérateurs classiques. Il en résulte un accroissement de chaleurs sensible et latente récupérées permettant, en moyenne, de doubler l'économie habituellement réalisée. Ces travaux ont démontré la faisabilité technique des solutions proposées dont la pénétration sur le marché doit être favorisée par leur faible coût d'insertion dans les installations existantes et leur temps de retour voisin de 2 ans. The gas-liquid and gas-gas heat exchangers developed respectively by the Société Nationale Elf Aquitaine (SNEA) and the Institut Français du Pétrole (IFP), within the framework of an AFME contract to promote innovation, make use of plastics to overcome the sulfuric condensation threshold of 180°C. Beyond this threshold, corrosion problems appear for conventional heat recovery processes. This results in an increase in the recovery of sensible and latent heat, so that the saving normally achieved can be doubled, on the average. This research has shown the technical feasibility of the solution proposed. The market penetration of these solutions should be enhanced by their low cost of insertion in existing installations and their payout time of about two years.

L'utilisation de mélanges non-azéotropiques comme fluides frigorigènes présente différents avantages en ce qui concerne le fonctionnement des installations de réfrigération / conditionnement / chauffage mettant en oeuvre des cycles thermodynamiques à compression avec changement de phase. En outre, de tels mélanges représentent une alternative intéressante aux corps purs actuellement recherchés pour résoudre les problèmes d'environnement liés à la destruction de la couche d'ozone. Cet article analyse les connaissances acquises concernant la mise en oeuvre d'une telle solution. The use of non-azeotropic mixtures as refrigerants has various advantages concerning the operating of refrigeration / air-conditioning / heating installations implementing thermodynamic compression cycles with a phase change. Likewise, such mixtures represent an interesting alternative to pure components which are now being looked to as a solution to environmental problems linked to the destruction of the ozone layer. This article analyzes what is known about the implementation of such a solution.

Six widely differing, novel capture processes, currently under development in Europe are described. These processes cover the range of postcombustion, precombustion and denitrogenation and show favourable possibilities for integration with power plants. They can be regarded as potential break-throughs in technical performance and/or costs.

A considerable increase in natural gas demand has been forecast for the coming years.Present-day supply sources will be unable to cover the growing demand in Europe and new suppliers will need to be called on more and more.Diversifying to new supply sources will entail heavy investments and is bound to mean rising costs.Technical progress is necessary to reduce costs, while protecting the environment and providing improved safety conditions. Innovative solutions in the areas of production, processing, transportation and chemical conversion should in the future widen the options and outlets available to operators.

The optimization of separation units in refining and natural-gas processing must take into consideration new needs and constraints that may seem incompatible. New installations must be designed not only on the basis of energy optimization but also by seeking to minimize investments and to respect new rules concerning environmental protection.The optimization described in this article is based on a thermodynamic analysis of different material and energy exchanges. The ''energy'' balance provides a suitable basis for making this analysis. It leads to the defining of an exergy efficiency that is all the higher as the thermodynamic irreversibilities are reduced, and that tends toward one for an ideal reversible system.For a separation process, a separation ''exergy'' term is defined that correspond to the ''minimum separation work''.Distillation is the basic separation operation. The exergy efficiency of this operation is low, and we show that, even in a relatively favorable cas, it is no greater than a value of about 6%. For an atmospheric distillation operation of crude oil, the exergy efficiency is about 4%. This overall exergy efficiency is the product of an external exergy efficiency and an internal exergy efficiency. The external exergy efficiency can be improved by better thermal integration among the units or by using cogeneration for supplying heat to the reboiler. Another possibility, that is sometimes used for superfractionation, consists in providing the heat required by the reboiler by overhead steam condensation after recompression. The internal exergy efficiency depends on the number and arrangement of the plates as well as on the composition of the mixture. In particular, it is found that separation by distillation of a component present in low concentration is very inefficient. The use of a separation agent - solvent or adsorbent - serves to separate a constituent that cannot be separated directly by distillation under satisfactory conditions. The separation process is optimized in this case by applying a procedure similar to the one followed for distillation.The integration of several functions in the same piece of equipment or of several transformation steps in the same process often reduces both the energy expenditures and the investments required. Several examples are developed in the text - case of an exchanger-dephlegmator, reactive distillation and absorption, integrated process for treating natural gas.These examples show how a thermodynamic analysis aiming to reduce irreversibilities leads to the designing of innovating processes.

L'échangeur gaz-gaz en matériau polymère, développé conjointement par la Société d'Équipements Thermiques et de Récupérateurs Métalliques (SETREM) et l'Institut Français du Pétrole (IFP), fait ici l'objet d'une description de son principe de base et des méthodes de modélisation développées par I'IFP. Le caractère modulaire de sa conception et les avantages spécifiques des matériaux polymères (inertie chimique, mise en oeuvre aisée, non adhérence des salissures, légèreté) constituent les principaux arguments des développements potentiels de cet échangeur. Parmi ceux-ci figure la récupération sur fumées de chaudière alimentée en fuel lourd n°2 dont l'intérêt a été démontré sur un prototype essayé au Centre d'Études et de Développement Industriels de I'IFP. Il est également fait état de la première application effective de cet échangeur pour la déshumidification des fumées issues de chaudières à gaz à condensation. On évite ainsi le tubage des conduits de fumées qui constitue un obstacle économique majeur à la diffusion de telles installations en chauffage collectif. Sont présentées enfin les caractéristiques d'un échangeur de ce type (surface d'échange : environ 5000 m²) assurant le séchage d'air humide dans une application du secteur agroalimentaire en cours de projet.

L'utilisation de mélanges non-azéotropiques comme fluides frigorigènes présente différents avantages en ce qui concerne le fonctionnement des installations de réfrigération / conditionnement / chauffage mettant en oeuvre des cycles thermodynamiques à compression avec changement de phase. En outre, de tels mélanges représentent une alternative intéressante aux corps purs actuellement recherchés pour résoudre les problèmes d'environnement liés à la destruction de la couche d'ozone. Cet article analyse les connaissances acquises concernant la mise en oeuvre d'une telle solution.

AIM : Research and development program of compression heat pumps operating with fluid mixtures. This work is being carried out by IFP and LEROY-SOMER.

The European market study carried out by IFP and Creusot-Loire in the present framework has shown that a 2 million tOE/yr saving can be expected from a new gas-gas heat recovery systems in the present industrial context. The main constraint to be overcome is the cost of setting them up in industrial plants. The compactness and modular conception of the new stacked perforated plates (SPP) gas-gas heat exchanger will undoubtedly help in getting this new equipment onto the market. The exchanger consists of a block formed by the stacking of judiciously superpositioned perforated metal plates whose apertures create the fluid flow passages. This compact gas-gas crossflow heat exchanger is easy to manufacture, with low pressure drops and easy-to-clean fumes passages. The different plate performation geometries, tested in laboratoiries on small models (exchange area = 0.35 M2) showed the possibility of attaining specific areas of 125 M2/m3 and heat transfer coefficients up to 70 W/m2 K. The data obtained from these tests serve as a basis for planning industrial devices and have been used to design a prototype (exchange area = 12.5 m2) which includes cleaning devices. The tests of this prototype carried out on a 1.6 MW boiler with fumes flowrates in the range of 2000 m3/h and outlet temperatures of up to 300°C, showed good correlations with the laboratory data. Furthermore these tests showed that specific heat transfer in excess of 5 kW/m3 K can be achieved which is an order of magnitude better than tubular type exchangers. A comparison of the projected cost of the SPP unit with a number of other heat exchangers indicates that the SPP unit is superior in terms of mass, size and cost and therefore will be very competitive in the market for heat recovery systems.

The problem of making use of low-level calories is a general one, in the light of the amount of thermal waste in numerous sectors. It is important both in the utilization of new energy sources available in thermal form and in the industrial field. In these cases, the low-level heat recovered can be utilized by means of systems operating on trithermal absorption cycles without compression and expansion devices. Recent progress in this field suggests that the extensive development of such techniques is likely. The performance attained with a new heat transformer developed by the Institut Français du Petrole is described. Various examples of industrial applications are presented and the economics are discussed.

The development of heat pumps in industry and for home heating appears to be one of the major aspects of energy conservation. Under present conditions, improving the coefficient of performance and lowering the investment are necessary conditions before heat pumps will become very wide-spread. In industry, the use of heat pumps has been very limited up to now. Considering home heating, reversible heat pumps are very common in the United States. This is much less the case in Europe where they are primarily used for heating rather than air conditioning. Nevertheless, the number of heat pumps produced in Europe is growing rapidly (see Table I).