Abstract:
Polishing compositions are described that are appropriate for fine polishing to very low tolerances. The polishing compositions include particles with small diameters with very narrow distributions in size and effectively no particles with diameters several times larger than the average diameter. Furthermore, the particles generally have very high uniformity with respect to having a single crystalline phase. Preferred particles have an average diameter less than about 200 nm. Laser pyrolysis processes are described for the production of the appropriate particles including metal oxides, metal carbides, metal sulfides, SiO2 and SiC.
Abstract:
A method for storing and releasing hydrogen fuel includes providing a hydrogenated material in a chamber, introducing a catalyst into the chamber, heating the chamber to about 190.degree. C., separating at least part of the material into dehydrogenated material and hydrogen and releasing the hydrogen from the chamber. A preferred catalyst is a transition metal complex, such as the iridium based complex IrH.sub.4 {2,6C.sub.6 H.sub.3 (CH.sub.2 P(C(CH.sub.3).sub.3).sub.2).sub.2 }. To reverse the process, a hydrogen pressure of about 10 atmospheres or more is provided, and the dehydrogenated material and hydrogen are combined at about or at least 100.degree. C. to regenerate the hydrogenated material. The small, lightweight system for carrying out the present method includes a chamber containing hydrogenated material and a catalyst, and having an outlet with a selectively permeable membrane for releasing hydrogen and containing hydrogenated material and a homogenous catalyst. A heat source for heating the material is positioned in, proximate to or remote from the chamber. A pressurizing hydrogen source delivers hydrogen gas to the chamber to regenerate the hydrogenated material. Vehicular apparatus or other devices requiring fuel sources may be retrofitted or equipped with the present system.
Abstract translation:用于储存和释放氢燃料的方法包括在室中提供氢化物质,将催化剂引入室中,将室加热至约190℃,将至少部分材料分离成脱氢材料和氢,并释放氢 从房间。 优选的催化剂是过渡金属络合物,例如铱基络合物IrH 4 {2,6 C 6 H 3(CH 2 P(C(CH 3)3)2)2}。 为了逆转该方法,提供约10个大气压或更高的氢气压力,并且脱氢的材料和氢气在约或至少100℃下合并以再生氢化材料。 用于实施本方法的小而轻的系统包括含有氢化材料和催化剂的室,并且具有用于释放氢气并含有氢化材料的选择性渗透膜的出口和均匀的催化剂。 用于加热材料的热源位于,靠近或远离室。 加压氢源将氢气输送到室以再生氢化材料。 可以对需要燃料源的车辆装置或其他装置进行改装或配备本系统。
Abstract:
A process is described for the catalytic cracking of ammonia present in a fluid containing hydrogen sulphide, in which the fluid is introduced into a reactor comprising a suitable catalyst and a catalytic cracking effluent is recovered. The temperature in the reaction zone is 1000.degree. C. to 1400.degree. C. and a reactor for carrying out the process comprises at least one heating chamber (3, 4) and at least one catalysis chamber (11) in which the ammonia is cracked without cracking the hydrogen sulphide. In a further variation, the reactor comprises at least one catalyst in the spaces defined between the heating elements.
Abstract:
A thermal reactor system that produces nanoscale powders by ultra-rapid thermal quench processing of high-temperature vapors through a boundary-layer converging-diverging nozzle. A gas suspension of precursor material is continuously fed to a thermal reaction chamber and vaporized under conditions that minimize superheating and favor nucleation of the resulting vapor. According to one aspect of the invention, the high temperature vapor is quenched using the principle of Joule-Thompson adiabatic expansion. Immediately after the initial nucleation stages, the vapor stream is passed through the nozzle and rapidly quenched through expansion at rates of at least 1,000.degree. C. per second, preferably greater than 1,000,000.degree. C. per second, to block the continued growth of the nucleated particles and produce a nanosize powder suspension of narrow particle-size distribution. According to another aspect of the invention, a gaseous boundary-layer stream is injected to form a blanket over the internal surface of the nozzle to prevent vapor condensation in the throat of the nozzle and its potential failure.
Abstract:
An apparatus for the thermal conversion of methane into hydrocarbons of higher molecular weight, comprising a reactor (1) of elongate form, connected on the one hand, at a first end, to an inlet for supplying gaseous mixture containing methane (process gas) and on the other, at the opposite end, to an outlet (10), the reactor comprising on the first end side a plurality of elements disposed in at least two layers disposed between two refractory walls, at least one refractory wall being disposed between the outside walls of the reactor, the layers being substantially parallel to the axis of the reactor, at least one of these layers comprising a series of sheaths (4) inside which there are electric heaters (3) which thus form a layer of heating elements, the elements being disposed in such a way as to define spaces or passages for the circulation of gaseous mixtures and/or effluents, the heaters and the sheaths being adapted to heat the said passages by successive independent cross-sections substantially at right-angles to the axis of the reactor, each cross-section comprising at least one transverse row of elements.
Abstract:
Apparatus suitable for the thermal conversion of methane to hydrocarbons of higher molecular weight, comprising an elongated reactor 1 provided with an inlet 5 for supplying a gas mixture containing methane (process gas) and an outlet at the opposite end, the reactor over a first part towards the inlet end having a plurality of electric heaters 3 surrounded by sheaths 4. The heaters, e.g., electric resistors, which are spaced apart and are substantially parallel with respect to one another, are arranged in substantially parallel rows perpendicular to the axis of the reactor so as to permit circulation of the process gas and/or effluent between the sheaths and/or between the sheaths and walls 22 separating two consecutive rows. The heaters heat the passages by successive independent cross sections substantially perpendicular to the axis of the reaction. Towards the outlet end, the reactor further comprises an injector for supplying cooling fluid, which cools the effluent. The reactor also has a hydrogen inlet for introducing a gas containing hydrogen into the space surrounding the heaters inside the sheaths 4 at an appropriate pressure. The reactor and the sheaths 4 are designed so that hydrogen is diffused from inside the sheaths to outside them and can then be diluted in the process gas.
Abstract:
The invention relates to a process and to an apparatus for the conversion of hydrocarbons. According to the invention, at least one first gas containing at least 20% oxygen by volume and a type of hydrocarbon are first of all circulated in separate streams which are parallel to each other, without their being mixed, according to a spatial distribution such that the first gas is surrounded by the hydrocarbon; these substances are introduced into a mixing/reaction chamber, at a first given circulation level, and while the substances are then allowed to mix, the oxygen and the hydrocarbon are ignited so as to give rise to the conversion reaction and then, at a second given circulation level situated downstream of the first, a quenching of the resultant mixture is performed in a chamber; whereupon, the resultant quenched conversion products are recovered. The invention applies particularly to the manufacture of conversion products such as acetylene and ethylene.
Abstract:
Integrated primary-secondary reforming operations are carried out with the partly reformed product effluent from the reformer tubes of the primary reforming zone passing to a catalyst-free reaction space at the feed end of a catalyst bed in the secondary reforming zone. The exothermic heat of reaction generated in said reaction space supplies the necessary heat for the endothermic reforming reaction that occurs in the catalyst bed of the secondary reforming zone, and the still hot secondary product effluent leaving the secondary reforming zone is passed in the shell side of the primary reformer zone to supply the endothermic heat of reaction required in said primary reforming zone. Essentially autothermal operating conditions are thereby achieved so as to essentially eliminate the necessity for employing an external fuel-fired primary reformer and/or for consuming a portion of the hyrocarbon feed material for fuel purposes.
Abstract:
This invention relates to a modified furnace for treating low-quality acid gas streams (those containing less than fifty percent (50%) hydrogen sulfide) to permit stable operation of combustion to provide a Claus furnace effluent. The system comprises burning a fuel gas and indirectly supplying the heat of this combustion to the hydrogen sulfide oxidant reaction wherein the hydrogen sulfide is converted to sulfur and other sulfur-containing products.
Abstract:
Process and apparatus are provided for preparing finely-divided silicon dioxide having high thickening capacity and good thixotropic properties by reaction of silicon fluoride in the vapor phase with water vapor, combustible gas and free oxygen-containing gas in a flame reaction zone to form silicon dioxide and hydrogen fluoride while cooling the gaseous reaction mixture in that portion of the reaction zone adjacent the base of the flame by contact with a cooling surface maintained at a temperature below 500.degree. C. but above the dew point of the reaction waste gases generated in the flame reaction.