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.

L'optimisation technico-économique des procédés industriels requiert de nouvelles techniques assurant un meilleur rendement énergétique et une protection accrue de l'environnement. Parmi celles-ci, l'échangeur de chaleur et de matière à parois poreuses proposé par l'Institut Français du Pétrole (IFP) est destiné aux opérations de séparation de mélanges gazeux contenant au moins un produit condensable. La première application assurée par Chaudières Seccacier SA concerne le chauffage au gaz industriel ou collectif. Le procédé consiste à effectuer le transfert de chaleur et d'eau entre fumées et air de combustion à travers une paroi poreuse qui assure la séparation des deux fluides par le film d'eau retenu par capillarité dans ses pores. Après la phase probatoire qui a concerné une chaudière de 200 kW, le développement en cours, avant la diffusion commerciale, s'effectue sur des chaudières de 500 kW. Le rendement énergétique est accru de 5 à 10 % si l'on se réfère aux chaudières à condensation, ce qui induit une réduction des émissions de CO2 de 20 à 50 % selon les installations et l'énergie déplacée. La réduction des émissions de NOx imputable à l'utilisation d'un air comburant saturé d'eau est de 65 % environ. The increase in the energy efficiency of processes is now a constant preoccupation that is included in all procedures aiming for the technico-economic optimization of industrial production. This trend is leading to the designing of systems integrating several simultaneous functions : chemical reaction, separation and heat transfer. In addition to the energy increase there is often a reduction in the bulk of installations, an improvement in reliability and better control of how the process operates. The porous-wall heat and mass exchanger (ECMP) proposed by Institut Français du Pétrole (IFP) for this purpose, which is covered by a basic patent, aims to separate gaseous mixtures containing at least one condensable product. The first application under the responsibility of Chaudières Seccacier SA involved industrial or district heating. The aim was to transfer part of the heat and water from the flue gases of a condensation boiler to the air of combustion. The ECMP was substituted for a heat exchange system based on patents held by Chaudières Seccacier SA and Gaz de France. Its job was to perform heat and mass transferts between the two fluids in two successive phases in two direct combustion air/water and flue-gas/water contact columns (Fig. 1a). The simplification made possible by the ECMP (Fig. 1b) stems from the performing of both operations in a single module. The two gases between which the heat and mass exchanges occur circulate on either side of a porous membrane, which, because of its hydrophilic nature and porous structure (pore diameters and porosity in particular), separates the two gases by a film of condensed water held in place by capillarity in its pores. In addition to the advantages of compactness and reliability thus obtained, this design defines the circulation spaces of the fluids (distance between two porous membranes, with both fluids being acted upon alternately) according to the pressure drops requested by the user. This technique is thus based mainly on the choice of the porous medium (nature of the constituent material, structure) so as to give the membrane the right properties for it to fulfill its heat and mass transfer and physical separation functions of the two fluids. In addition to these purely operational aspects, the membrane must also meet the technological constraints required by the manufacturing and the physical operating conditions. The analysis of the functional roles (heat and mass transfer, separation) leads to a definition of the range of pore diameters capable of ensuring both mass transfer according to a kinetics compatible with the flow rates required by the evaporation and condensation phases and the capillary retention of water to create a film resisting the pressure variations that may occur on either side of the wall. The values to which this analysis leads obviously depend on the specific conditions chosen by the user. However, it can be assumed that the pore diameters must not exceed 150 µm for applications of the type considered. The choice of the nature of the material making up the porous medium is very large : metals, polymers, glass or composites. The way they are implemented also covers a wide range : sintering, felting, weaving. The obvious simplification resulting from the use of the ECMP for the applications developed by Chaudières Seccacier SA (Figs. 4 and 5) gives access to this means of recovery for the market for medium-powered boilers of around 500 kW, which, to date, has been inaccessible for systems implementing two coupled heat-exchange columns. The increase in the energy efficiency of boilers equipped with the ECMP and technological improvements making for optimum boiler operating (now fed With saturated air at a temperature close to that of the flue gases) is between 5 and 10% when referring to conventional condensation boilers and between 1 and 5% compared to boilers equipped with the device including the two heat-exchange columns (Fig. 6). Likewise, the impact on the environment resulting from the increase in efficiency and the use of water-saturated oxidizer air results during operating in a reduction of emissions, which, for CO2, is between 20 and 50% depending on the installations and the energy displaced, and about 65% for NOx (Fig. 7). After probatory tests performed on a 200 kW boiler, thus confirming the proper choice of the porous medium, development is continuing on 500 kW boilers (Fig. 8) designed for district heating. This achievement displayed at EXPOTHERM 92 was the reason why Chaudières Seccacier SA received the Super Oscar for Innovation.

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.

Cet article fait le point, sous forme résumée, des travaux de recherches et de développement menés par l'Institut Français du Pétrole (IFP) depuis vingt ans dans le domaine des piles à combustible : sélection des filières directes conduisant au choix de la pile hydrogène-air basse température à électrolyte basique, mise au point des générateurs à hydrogène alimentés en méthanol. On présente les résultats obtenus et les conclusions des enquêtes effectués dans le domaine des groupes électrogènes et des applications spéciales, dans celui de la traction automobile et dans celui de la production massive d'électricité. This article reviews and sums up the research and development done by Institut Français du Pétrole (IFP) in the last 20 years in the field of fuel cells, including the selection of direct methods leading to the choice of low-temperature basic-electrolyte hydrogen/air cells and the development of methanol-powered hydrogen generators. The results obtained are desceibed along with the conclusions of surveys made in the field of electric generators and special applications in the fields of automotive traction and massive electricity production.

L'echangeur a membrane poreuse de la chaudiere ALTAREX constitue une nouvelle approche technologique de la pompe a vapeur d'eau, echangeur massique et thermique qui utilise l'air comburant comme source froide annexe pour recycler l'energie sensible et latente residuelle habituellement rejetee a la cheminee. Ceci signifie que la chaudiere ALTAREX peut recuperer la totalite du pouvoir calorifique superieur du combustible gaz naturel. Aux performances energetiques du procede s'ajoutent les qualites ecologiques d'une combustion avec de l'air fortement enrichi en vapeur d'eau, combustion qui aboutit a une tres faible formation d'oxydes d'azote. Son efficacite energetique et ecologique font de la chaudiere ALTAREX un generateur de chaleur de reference mondiale.

L'optimisation technico-économique des procédés industriels requiert de nouvelles techniques assurant un meilleur rendement énergétique et une protection accrue de l'environnement. Parmi celles-ci, l'échangeur de chaleur et de matière à parois poreuses proposé par l'Institut Français du Pétrole (IFP) est destiné aux opérations de séparation de mélanges gazeux contenant au moins un produit condensable. La première application assurée par Chaudières Seccacier SA concerne le chauffage au gaz industriel ou collectif. Le procédé consiste à effectuer le transfert de chaleur et d'eau entre fumées et air de combustion à travers une paroi poreuse qui assure la séparation des deux fluides par le film d'eau retenu par capillarité dans ses pores. Après la phase probatoire qui a concerné une chaudière de 200 kW, le développement en cours, avant la diffusion commerciale, s'effectue sur des chaudières de 500 kW. Le rendement énergétique est accru de 5 à 10 % si l'on se réfère aux chaudières à condensation, ce qui induit une réduction des émissions de CO2 de 20 à 50 % selon les installations et l'énergie déplacée. La réduction des émissions de NOx imputable à l'utilisation d'un air comburant saturé d'eau est de 65 % environ.

The increase in the energy efficiency of processes is now a constant preoccupation that is included in all procedures aiming for the technico-economic optimization of industrial production. This trend is leading to the designing of systems integrating several simultaneous functions: chemical reaction, separation and heat transfer. In addition to the energy increase there is often a reduction in the bulk of installations, an improvement in reliability and better control of how the process operates.The porous-wall heat and mass exchanger (ECMP) proposed by Institut Francais du Petrole (IFP) for this purpose, which is covered by a basic patent, aims to separate gaseous mixtures containing at least one condensable product. The first application under the responsibility of Chaudieres Seccacier SA involved industrial or district heating. The aim was to transfer part of the heat and water from the flue gases of a condensation boiler to the air of combustion. The ECMP was substituted for a heat exchange system based on patents held by Chaudieres Seccacier SA and Gaz de France. Its job was to perform heat and mass transferts between the two fluids in two successive phases in two direct combustion air/water and flue-gas/water contact columns (Fig. 1a). The simplification made possible by the ECMP (Fig. 1b) stems from the performing of both operations in a single module. The two gases between which the heat and mass exchanges occur circulate on either side of a porous membrane, which, because of its hydrophilic nature and porous structure (pore diameters and porosity in particular), separates the two gases by a film of condensed water held in place by capillarity in its pores. In addition to the advantages of compactness and reliability thus obtained, this design defines the circulation spaces of the fluids (distance between two porous membranes, with both fluids being acted upon alternately) according to the pressure drops requested by the user.This technique is thus based mainly on the choice of the porous medium (nature of the constituent material, structure) so as to give the membrane the right properties for it to fulfill its heat and mass transfer and physical separation functions of the two fluids. In addition to these purely operational aspects, the membrane must also meet the technological constraints required by the manufacturing and the physical operating conditions.The analysis of the functional roles (heat and mass transfer, separation) leads to a definition of the range of pore diameters capable of ensuring both mass transfer according to a kinetics compatible with the flow rates required by the evaporation and condensation phases and the capillary retention of water to create a film resisting the pressure variations that may occur on either side of the wall. The values to which this analysis leads obviously depend on the specific conditions chosen by the user. However, it can be assumed that the pore diameters must not exceed 150 mum for applications of the type considered. The choice of the nature of the material making up the porous medium is very large: metals, polymers, glass or composites. The way they are implemented also covers a wide range: sintering, felting, weaving.The obvious simplification resulting from the use of the ECMP for the applications developed by Chaudieres Seccacier SA (Figs. 4 and 5) gives access to this means of recovery for the market for medium-powered boilers of around 500 kW, which, to date, has been inaccessible for systems implementing two coupled heat-exchange columns. The increase in the energy efficiency of boilers equipped with the ECMP and technological improvements making for optimum boiler operating (now fed with saturated air at a temperature close to that of the flue gases) is between 5 and 10% when referring to conventional condensation boilers and between 1 and 5% compared to boilers equipped with the device including the two heat-exchange columns (Fig. 6).Likewise, the impact on the environment resulting from the increase in efficiency and the use of water-saturated oxidizer air results during operating in a reduction of emissions, which, for CO2, is between 20 and 50% depending on the installations and the energy displaced, and about 65% for NO(x) (Fig. 7).After probatory tests performed on a 200 kW boiler, thus confirming the proper choice of the porous medium, development is continuing on 500 kW boilers (Fig. 8) designed for district heating. This achievement displayed at EXPOTHERM 92 was the reason why Chaudieres Seccacier SA received the Super Oscar for Innovation.

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 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.

Cet article fait le point, sous forme résumée, des travaux de recherches et de développement menés par l'Institut Français du Pétrole (IFP) depuis vingt ans dans le domaine des piles à combustible : sélection des filières directes conduisant au choix de la pile hydrogène-air basse température à électrolyte basique, mise au point des générateurs à hydrogène alimentés en méthanol. On présente les résultats obtenus et les conclusions des enquêtes effectués dans le domaine des groupes électrogènes et des applications spéciales, dans celui de la traction automobile et dans celui de la production massive d'électricité.