An intermediate substrate includes a handle substrate bonded to a thin layer suitable for epitaxial growth of a compound semiconductor layer, such as a III-nitride semiconductor layer. The handle substrate may be a metal or metal alloy substrate, such as a molybdenum or molybdenum alloy substrate, while the thin layer may be a sapphire layer. A method of making the intermediate substrate includes forming a weak interface in the source substrate, bonding the source substrate to the handle substrate, and exfoliating the thin layer from the source substrate such that the thin layer remains bonded to the handle substrate.

Bonded intermediate substrate and method of making same

Process for gas-phase polymerization carried out in two interconnected polymerization zones, to which one or more α-olefins CH2=CHR are fed in the presence of catalyst under reaction conditions and from which the polymer product is discharged. The process is characterized in that the growing polymer flows through a first polymerization zone under fast fluidization conditions, leaves said first zone and enters a second polymerization zone through which it flows in a densified form under the action of gravity, leaves said second zone and is reintroduced into the first polymerization zone, thus establishing a circulation of polymer around the two polymerization zones. The novel process allows olefins to be polymerized in the gas phase with high productivity per unit volume of the reactor without incurring the problems of the fluidized-bed technologies of the known state of the art.

Process and apparatus for the gas-phase polymerization of alpha-olefins

A multi-junction solar cell includes a silicon solar subcell, a GaInP solar subcell, and a GaAs solar subcell located between the silicon solar subcell and the GaInP solar subcell. The GaAs solar subcell is bonded to the silicon solar subcell such that a bonded interface exists between these subcells.

GaInP/GaAs/Si TRIPLE JUNCTION SOLAR CELL ENABLED BY WAFER BONDING AND LAYER TRANSFER

Apparatuses and methods are provided for producing liquefied gas, such as liquefied natural gas. In one embodiment, a liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream may sequentially pass through a compressor and an expander. The process stream may also pass through a compressor. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. A portion of the liquid gas may be used for additional cooling. Gas produced within the system may be recompressed for reintroduction into a receiving line.

Apparatus for the liquefaction of natural gas and methods relating to same

Process for the gas-phase polymerization of one or more alpha-olefins in the presence of a catalyst system, the process comprising: contacting in a continuous way one or more of said alpha-olefins with said catalyst system in a prepolymerization reactor, wherein the reaction is carried out in a liquid medium at a temperature ranging from 23° to 500C; feeding in continuous the prepolymer obtained in step a) into a gas-phase reactor having interconnected polymerization zones, where the growing polymer particles flow upward through a first polymerization zone (riser) under fast fluidization or transport conditions, leave said riser and enter a second polymerization zone (downcomer) through which they flow downward under the action of gravity, leave said downcomer and are reintroduced into said riser; wherein the prepolymer obtained from step a) is continuously fed at a section of said riser characterized by an upwardly gas velocity higher than 3.0 m/s.

Process for the gas-phase polymerization of olefins

A process and a device for the catalytic dehydrogenation of a C 2+ paraffinic hydrocarbon charge is applicable to the synthesis of methyl tert-butyl ether. Effluent coming from the dehydrogenation reactor and containing olefins and water is cooled in at least one heat exchanger (41), saturated with water in a column (3) and sent to a stripping column (10) where it is at least partly put in contact with a recycled aqueous liquid phase containing a solvent, preferably methanol. The compressed gaseous effluent in which the water is thereby inhibited from freezing by the methanol is cooled in a heat exchanger (13) then separated in separator (8) into olefins and into hydrogen. An aqueous liquid phase with methanol is decanted at (8) and recycled in column (10).

Process and device for catalytic dehydrogenation of a C2+ paraffinic charge comprising means for inhibiting the freezing of water in the effluent

The specification describes a method and a fixed bed apparatus for producing olefinic hydrocarbons from a charge of saturated aliphatic hydrocarbons with 2 to 20 carbon atoms and hydrogen in a chamber 1 comprising a plurality of parallel tubes 3 filled with a catalyst and arranged in rows. A so-called reaction phase and a catalyst-regenerating phase are carried out in the tubes of the chamber. The tubes are heated by appropriate radiant heating means 6 , arranged in layers substantially perpendicular to the tubes. These layers heat a first part of the tubes (at the feed side) with a heat flux greater than the mean heat flux of the chamber and a second, subsequent part with a mean flux no more than equal to the mean heat flux, so that the isothermicity of the catalyst is substantially maintained, using appropriate control means.

Method and apparatus for the dehydrogenation of aliphatic hydrocarbons to olefinic hydrocarbons.

Process for catalytic conversion of a feed stock containing a major part of at least one oxygen-containing compound into olefinic hydrocarbons. This process comprises a thermal control of the fluidised catalyst beds with the aid of a heat exchanger. The catalyst circulates essentially from the base of a vessel (1) into a heat exchanger (6) comprising an internal separating partition which defines two elongate and adjacent compartments communicating via their lower part. In the compartment where the catalyst flows downwards the rate of fluidisation is between 0.1 cm/s and 2 m/s, while in the compartment where the catalyst rises in the heat exchanger (6) the fluidisation velocity is between 0.1 and 6 m/s.

Process for the conversion in a fluidized bed of a feed consisting mainly of an oxygenated compound.

A process and a device for catalytic dehydrogenation of a C2+ paraffinic cut with an improved system for cooling the effluent is applicable, for example, to the synthesis of methyl tert-butyl ether. Liquid charge 12 is evaporated in the calandria of a heat exchanger 13 in the optional presence of at least one part recycled hydrogen 15, then optionally compressed in a compressor 14 before being preheated in an exchanger 41 by effluent 1 and introduced into a dehydrogenation reactor 40. The effluent cooled in the tubes of exchanger 13 can be mixed with a cryogenic phase 17 resulting from the isentropic expansion of a hydrogen-rich phase separated in a separator 8, the hydrogen optionally being recycled to the calandria of the heat exchanger. The olefins recovered with the unconverted paraffins are stabilized in a column 20.

Process and device for catalytic dehydrogenation of a c2+ paraffinic charge comprising a self-cooling system

The invention concerns an isomerisation process for n-olefins containing at most 20 carbon atoms, consisting of bringing a feed containing the olefins into contact with an alumina based catalyst impregnated with 0.03% to 0.6% by weight of titanium and 0.05% to 5% by weight of an oxide of an element from group IIIA. The process can then be carried out in the presence of a small quantity of steam or it can be carried out in the absence of steam.

Burzynski Jean-Pierre

Papers

Process and device for catalytic dehydrogenation of a C2+ paraffinic charge comprising means for inhibiting the freezing of water in the effluent

Method and apparatus for the dehydrogenation of aliphatic hydrocarbons to olefinic hydrocarbons.

Process for the conversion in a fluidized bed of a feed consisting mainly of an oxygenated compound.

Process and device for catalytic dehydrogenation of a c2+ paraffinic charge comprising a self-cooling system

Olefin isomerisation process