Abstract: A nuclear reactor includes a vessel having an outer wall and vessel bottom, and an enclosure delimited by a cylindrical inner wall disposed inside the vessel such that the inner wall and outer wall define a circuit with an annular cross-section. A support element is located adjacent the bottom of the enclosure to hold control elements of the core. A flow diffusion element is positioned between the support element and the vessel bottom and has a circular flat surface portion including disc shaped orifices of the same diameter. The space between the flat portion and the vessel bottom forms an unobstructed mixing zone to allow uniform distribution of flow rates of fluid circulated through the enclosure.

Abstract: The invention relates to a flow calming assembly for a nuclear reactor comprising a vessel (2), an enclosure (5) located in the vessel (2), a fluid being circulated between the vessel (2) and the enclosure (5) in order to then circulate in the enclosure (5) after a reversal of its direction of circulation, a diffusion element (9) being configured to limit the formation of swirling flows in the enclosure (5) and make the distribution of the flow rates uniform over the cross-section of the enclosure (5), a diffusion element (9) and a flow calming method in such a reactor.

Abstract: A method and apparatus for steam cracking hydrocarbons, which method consists in heating a mixture of hydrocarbons and steam to a desired temperature that is high enough to crack the hydrocarbons and transform them into olefins, the source of energy needed for heating the mixture is supplied essentially by cogeneration using combustion of a fuel to produce simultaneously both heat energy and mechanical work which is transformed into electricity by an alternator, and wherein the mixture is initially subjected to preheating using the heat energy supplied by the cogeneration and is subsequently heated to the desired cracking temperature by means of electrical heating using the electricity supplied by the cogeneration.

Abstract: A method and apparatus for steam cracking hydrocarbons, which method consists in heating a mixture of hydrocarbons and steam to a desired temperature that is high enough to crack the hydrocarbons and transform them into olefins, the method being characterized in that the source of energy needed for heating the mixture is supplied essentially by cogeneration using combustion of a fuel to produce simultaneously both heat energy and mechanical work which is transformed into electricity by an alternator, and in that the mixture is initially subjected to preheating using the heat energy supplied by the cogeneration, and is subsequently heated to the desired cracking temperature by means of electrical heating using the electricity supplied by the cogeneration.

Abstract: The technical field of the invention is that of manufacturing heat treatment apparatuses such as furnaces for thermally cracking chemical substances, in particular hydrocarbons.

Abstract: The present invention relates to a method of manufacturing one or more chemical products in which a chemical reaction is performed by causing one or more reagents to flow along the inside of a tube disposed in a radiation zone of a furnace. In the method, at least a portion of the tube is caused to vibrate so as to limit the deposition of reaction by-products on the inside wall of the tube. More particularly, the tube can be vibrated at a frequency lying in the range 50 Hz to 2000 Hz. The invention also provides apparatus for performing the method of the invention, which apparatus comprises a furnace including a radiation thermal enclosure through which at least one tube passes, which tube is provided with at least one excitation means suitable for generating tube vibration.

Abstract: The technical field of the invention is the field of methods and apparatus for thermally cracking chemicals. The present invention provides a method and apparatus for measuring the vibration of a duct in which there flows at least one fluid and which is disposed inside a thermal enclosure at high temperature, wherein a vibration sensor is used that is located inside the enclosure.

Abstract: The present invention relates to a method of manufacturing one or more chemical products in which a chemical reaction is performed by causing one or more reagents to flow along the inside of a tube disposed in a radiation zone of a furnace. In the method, at least a portion of the tube is caused to vibrate so as to limit the deposition of reaction by-products on the inside wall of the tube. More particularly, the tube can be vibrated at a frequency lying in the range 50 Hz to 2000 Hz. The invention also provides apparatus for performing the method of the invention, which apparatus comprises a furnace including a radiation thermal enclosure through which at least one tube passes, which tube is provided with at least one excitation means suitable for generating tube vibration.

Abstract: Apparatus for the cracking of hydrocarbons in the presence of steam for the production of olefins and diolefins which includes a thermal radiation enclosure enclosing at least one cracking tube having an inlet to which the hydrocarbons and steam are supplied and having an outlet for the cracking products. The internal diameter of the tube diminishes continuously or discontinuously from the inlet to the outlet and the ratio between the internal diameters of the tube at the inlet and the outlet is between 1.2 and 3. The ratio of the length of the tube within the enclosure to the mean internal diameter of the tube is between 200 and 600. Heat is supplied to the tube by burners within the enclosure so that the thermal power applied along the length of the tube increases in the direction from the inlet to the outlet and so that the ratio between the thermal power applied to the half of the tube extending from the inlet to the thermal power applied to the remaining half of the tube is between 40/60 and 15/85.

Abstract: The present invention relates to a process for the preparation of olefins by the cracking of hydrocarbons consisting in passing a mixture of hydrocarbons and steam flowing in a cracking tube disposed inside a radiation zone of a furnace. The process is characterized in that an increase of the cracking temperature of the mixture between the inlet and the outlet of the radiation zone is associated to a non-homogeneous distribution of the thermal power of the furnace, greater at the beginning of the cracking tube than at the end, and to a reaction volume which is greater in the second half of the length tube than in the first one. The present invention relates also to a cracking furnace in which between the inlet and the outlet of the radiation zone the diameter of the cracking tube increases and the thermal power of the burners used to heat the cracking tube decreases.

Abstract: The present invention relates to a process for the preparation of olefins and diolefins by the cracking of hydrocarbons in the presence of steam, consisting in passing a mixture of hydrocarbons and steam flowing in a cracking tube disposed inside a radiation zone of a furnace. The process is characterized in that the mean dwell time of the mixture of flowing in the cracking tube between the inlet and the outlet of the radiation zone is from 300 to 1800 milliseconds, and the reaction volume is greater in the first half of the tube length than in the second one. The present invention relates also to a cracking furnace in which the ratio between the length and the mean diameter of the cracking tube is from 200 to 600, and the tube diameter decreases from the inlet to the outlet of the radiation zone.

Abstract: The present invention relates to a process for the preparation of olefins by the cracking of hydrocarbons consisting in passing a mixture of hydrocarbons and steam flowing in a cracking tube disposed inside a radiation zone of a furnace. The process is characterized in that an increase of the cracking temperature of the mixture between the inlet and the outlet of the radiation zone is associated to a non-homogeneous distribution of the thermal power of the furnace, greater at the beginning of the cracking tube than at the end, and to a reaction volume which is greater in the second half of the length tube than in the first one.The present invention relates also to a cracking furnace in which between the inlet and the outlet of the radiation zone the diameter of the cracking tube increases and the thermal power of the heating means decreases.