Abstract: The heat recovery boiler (1) is operated, at least temporarily, by feeding its combustion system with air (13) and with a stream (15) of flue gases (4) recycled to a level of at least 45%, typically between 50 and 65%, so as to allow the efficiency of the boiler to be increased and to decouple it, at least temporarily, from the combustion engine (8) driving a generator (9), the exhaust gases from which are burnt in post-combustion mode in the boiler in cogeneration mode.

Abstract: The heat recovery boiler (1) is operated, at least temporarily, by feeding its combustion system with air (13) and with a stream (15) of flue gases (4) recycled to a level of at least 45%, typically between 50 and 65%, so as to allow the efficiency of the boiler to be increased and to decouple it, at least temporarily, from the combustion engine (8) driving a generator (9), the exhaust gases from which are burnt in post-combustion mode in the boiler in cogeneration mode.

Abstract: A macroporous adsorbent comprising pores having a pore volume (Vm) and a mean pore diameter (dm) such that: Vm≧1 cc.g−1 and dm≧1 &mgr;m, Vm and dm being determined by mercury porosimetry; their manufacturing process using a spheronization and freeze-drying technique; and their use for separating or purifying gases, such as air, synthesis gases or hydrocarbons, especially olefins.

Abstract: A PSA, especially VSA, process for separating a stream of gas, such as air, containing at least one first compound, such as nitrogen, which is preferentially adsorbed on at least one adsorbent and at least one second compound, such as oxygen, which is adsorbed less preferentially on the adsorbent than the first compound. The adsorbent comprises at least particles of a zeolite having a Si/Al ratio of less than or equal to 5 and chosen from zeolites of X or A type, the zeolite having a kinetics coefficient (ak) and an intrinsic strength (&agr;), with: ak>0.5 s−1 and 0.10<&agr;<2. The invention also relates to an adsorbent for the non-cryogenic separation of gases, especially the gases from air and from syngas.

Abstract: A process for manufacturing particles of type X zeolite exchanged with at least lithium cations and having an Si/Al ratio less than or equal to 1.5, in which (a) at least one mother liquor containing lithium salts having a molar purity in excess of 95% is percolated through a bed of zeolite particles, the mother liquor making it possible to obtain a limit exchange factor (LEF) for the zeolite particles of between 90 and 100%, (b) the percolation of the mother liquor is stopped when an amount of mother liquor has been used which makes it possible to obtain a mean real exchange factor (REF) such that: REF=LEF−2%±1%; and (c) the lithium-exchanged zeolite particles are recovered. The particles of faujasite, preferably X, zeolite exchanged to at least 88% with lithium cations and having an Si/Al ratio less than or equal to 1.5 which are obtained by such a manufacturing process can be used as adsorbent in a PSA, preferably VSA, process for separating or purifying a gas flow.

Abstract: A PSA or VSA process for separating a gas flow, such as air, containing at least one first gas compound, such as nitrogen, which is preferentially adsorbed on at least one adsorbent, and at least one second gas compound, such as oxygen, which is adsorbed less preferentially on at least the one adsorbent than the first gas compound. The adsorbent used comprises particles of faujasite zeolite having a Si/Al ratio <1.5, such as a LSX zeolite, and containing 80 to 99% Li+ cations, 0.01 to 25% Na+ cations, 0.01% to 10% Mg2 cations, 0.01% to 10% Ca2+ cations and 0 to 3% K+ cations.

Abstract: A PSA process for separating a gas flow, such as air, containing a first gas compound, such as nitrogen, which is adsorbed preferentially on an adsorbent, and a second gas compound, such as oxygen, which is adsorbed less preferentially on the adsorbent than the first gas compound. The adsorbent is formed by an aggregate comprising a zeolite phase and a binder, and contains elements Si, Al, Li, Na, Mg, K and Ca, the total proportions of these elements in the adsorbent being such that the Si/Al ratio is between 1 and 2.4, the Na/Li ratio is between 0.012 and 0.300, the Mg/Li ratio is between 0.012 and 0.400, the Ca/Li ratio is between 0.012 and 0.200, and the K/Li ratio is between 0.001 and 0.060.

Abstract: Aggregated absorbent particles having a shape similar to an ellipsoid, which has a first axis (A—A) of length (a), a second axis (B—B) of length (b) and a third axis (C—C) of length (c), the first, second and third axes being orthogonal. The lengths of the first, second and third axes are such that: a>b≧c, and the ratio (a/b) of the length (a) of the first axis (A—A) to the length (b) of the second axis (B—B) is such that: 1.05<a/b<2.50. These aggregated absorbent particles are used in a gas production unit, in particular a PSA unit with radial geometry, for implementing a process of separating a gas flow, such as air or a syngas, with a view to producing, in particular, oxygen with a purity of at least 90%, hydrogen or purified air which can subsequently be separated by cryogenic distillation.

Abstract: A PSA process for the separation of a feed gas, for example air, containing at least one first component, such as nitrogen, and a second component, such as oxygen, by preferential adsorption of the first component at a high adsorption pressure, on at least one bed of particles of an adsorbent material and recovery of a gas flow enriched in the second component, with desorption of the first component at a low desorption pressure. The ratio (.mu./.sigma.) of the mean granulometry (.mu.) of the adsorbent particles contained in the bed, to the breadth of granulometric distribution (.sigma.) of the particles, is comprised within the range 1.5 to 15, the particles of adsorbent material being particles of zeolite, such as zeolite X or zeolite LSX, exchanged by metallic cations, preferably cations of lithium and/or calcium.

Abstract: A heterogeneous adsorbent for the separation of gases, comprising particles of at least one zeolite containing at least one exchanged metal cation selected from monovalent, divalent and/or trivalent cations, the zeolite having an exchange-factor distribution of given mean having a standard deviation for the exchange-factor distribution of between about 0.3% and 5%, and a PSA, VSA or TSA process for separation of a gas flow, such as air, containing at least a first compound, such as nitrogen, which is adsorbed preferentially on the heterogeneous adsorbent, and at least a second compound, such as oxygen, which is less preferentially adsorbed on the heterogeneous adsorbent than the first compound.

Abstract: For the separation of nitrogen from oxygen in air, an adsorbent is used which preferentially adsorbs the nitrogen. The adsorbent is a heterogeneous zeolite whose particles have a distribution of the capacity to adsorb nitrogen relative to oxygen, with a ratio (.sigma..sub.c /.mu..sub.c) comprised between 0.02 and 0.15, and/or having a distribution of selectivity of adsorption of nitrogen relative to oxygen with a ratio (.sigma..sub.s /.mu..sub.s) comprised between 0.02 and 0.25.

Abstract: Each adsorber (1, 2) is dimensioned in such a way that it operates in substantially adiabatic mode and its production dead volume (27), which is the free volume in permanent communication with the outlet side end of the mass of adsorbent (6), is between about 10% and 60% of the volume of the mass of adsorbent. Oxygen may thus be produced from atmospheric air.

Abstract: A process for the separation of a gas mixture containing oxygen and nitrogen, including bringing the mixture into contact in an adsorption zone with a first selective adsorbent for nitrogen of faujasite type exchanged to at least 80% with lithium, in which the Si/Al ratio is lower than 1.5 and a second selective adsorbent for nitrogen of zeolite type exchanged with divalent cations such as the alkaline-earth metal or transition metal cations. The second adsorbent is characterized by a nitrogen adsorptivity C.sub.2 lower than the nitrogen adsorptivity C.sub.1 characterizing the first adsorbent, and an adsorption selectivity for nitrogen in relation to oxygen (1.times.10.sup.5 Pa, 20.degree. C.) higher than or equal to 3.