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: An improved heated fluidized bed reactor and method for the production of high purity polycrystalline silicon by silane pyrolysis wherein silicon seed particles are heated in an upper heating zone of the reactor and admixed with particles in a lower zone, in which zone a silane-containing gas stream, having passed through a lower cooled gas distribution zone not conducive to silane pyrolysis, contacts the heated seed particles whereon the silane is heterogeneously reduced to silicon.

Abstract: This invention relates to the manufacture of high-purity polycrystalline silicon rods by the pyrolysis of silane. More specifically, the present invention relates to an improved method for pyrolyzing monosilane to form high-quality polycrystalline rods of uniform diameter and to an improved pyrolysis reactor system for forming high-quality polycrystalline silicon rods of uniform diameter at high production rates.

Abstract: An integrated pressure swing adsorption/membrane separation process is disclosed for the separation and purification of at least one gas component of a feed gas in which the purge effluent from the pressure swing adsorption part of the system is passed through a membrane separation unit to produce a non-permeate which is utilized as a displacement gas in the pressure swing adsorption part of the system. Desirably, the permeate is also utilized as a purge gas or repressurization gas. The apparatus for carrying out the process is also disclosed.

Abstract: This invention relates to an improved more energy efficient process for the separation of aromatic and non-aromatic hydrocarbons from a mixed carbon feed which comprises the following steps:(a) contacting said feed in an extraction zone with an extraction solvent to provide an aromatic-rich solvent phase and a raffinate phase;(b) cooling said aromatic-rich solvent and raffinate phases;(c) introducing said cooled aromatic-rich solvent phase to a separation zone containing aromatic hydrocarbons and a solvent-rich phase containing mixed extraction solvent and water;(d) introducing said cooled raffinate phase to a separation zone in the presence of water as based on the total weight of water and the raffinate phase to provide a raffinate phase containing non-aromatic hydrocarbons and a solvent/water phase;(e) adjusting the water present in the solvent-rich phase of step (c) and the solvent/water phase of step (d);(f) recycling at least or portion the phases in step (e) to step (a);(g) separately contacting the ra

Abstract: The present invention is directed to an improvement in an alkylation process involving effluent refrigeration in which an enhanced boiling surface heat exchanger is utilized in the alkylation reaction zone so as to carry out the reaction at its optimum reaction temperature and at a positive compressor suction pressure.

Abstract: The present invention provides a method and apparatus for automatically controlling product repressurization in a pressure swing adsorption (PSA) process. According to the invention the same valve employed for withdrawing product from a bed during adsorption is employed to feed product gas to that bed during product repressurization. This enables the elimination of several valves, including a system-dependent valve, thereby improving system reliability. The same controllable valve may also be used to control the pressure in the PSA system.

Abstract: An apparatus for the production of ammonia synthesis gas comprises a hydrocarbon convertor for converting a hydrocarbon feed to an effluent containing hydrogen and carbon monoxide by reaction with air which hydrocarbon convertor includes means to provide air in excess of the stoichiometric amount of nitrogen required for ammonia synthesis. The effluent from the hydrocarbon convertor is in communication with a water gas shift convertor for converting the carbon monoxide in the effluent to carbon dioxide. The water gas shift convertor is in communication with a pressure-swing adsorption system capable of selectively adsorbing carbon dioxide, carbon monoxide, methane and other impurities from hydrogen and a portion of the nitrogen fed in the gas mixture to the pressure swing adsorption system. The pressure swing adsorption system is provided with a conduit for discharging a partially purified ammonia synthesis gas mixture of hydrogen and nitrogen and a conduit for discharging purge gas.

Abstract: Method for treating waste slurries containing solid impurities, e.g. in the form of metal chlorides, and silicon tetrachloride and trichlorosilane by evaporation and separation techniques to recover more of the silicon tetrachloride and trichlorosilane.

Abstract: Carbon monoxide is recovered as the intermediate component of a reformer effluent containing hydrogen, carbon monoxide and carbon dioxide in a pressure swing adsorption system by the introduction of a gas displacement step before, simultaneous with or subsequent to pressure equalization between beds of a multi-bed adsorption system, with a cocurrent depressurization step being employed to recover said CO product. The carbon dioxide-rich countercurrent depressurization and/or purge effluent is recycled to the reformer for reaction with natural gas or other feed gas, with no carbon dioxide scrubbing step being employed before passage of the reformer effluent to the pressure swing adsorption system.

Abstract: A pressure swing adsorption process is disclosed wherein binary gas purification is effected from a single adsorbent bed. An adsorbent bed is charged under pressure with a gas mixture having some components that are more adsorbable than others. The process causes the bed to be polarized with one end of the bed containing the more adsorbable components and the other end containing the less adsorbable components. Once charged, the bed is depressurized simultaneously from both ends, thus removing the separated components from their respective ends.

Abstract: Silicon tetrachloride, hydrogen and metallurgical silicon are reacted at about 400.degree.-600.degree. C. and at pressures in excess of 100 psi, and specifically from about 300 up to about 600 psi to form di- and trichlorosilane that is subjected to disproportionation in the presence of an anion exchange resin to form high purity silane. By-product and unreacted materials are recycled, with metallurgical silicon and hydrogen being essentially the only consumed feed materials. The silane product may be further purified, as by means of activated carbon or cryogenic distillation, and decomposed in a fluid bed or free space reactor to form high purity polycrystalline silicon and by-product hydrogen which can be recycled for further use. The process results in simplified waste disposal operations and enhances the overall conversion of metallurgical grade silicon to silane and high purity silicon for solar cell and semiconductor silicon applications.

Abstract: In a steam distillation process for the recovery of aromatic hydrocarbons wherein there is (i) a primary flash zone at the top of the distillation zone in which rich solvent is flashed and/or (ii) provision for the removal of side cut distillate vapors from about the middle of the distillation zone, the improvement comprising (a) heat exchanging flashed rich solvent vapors or side-cut distillate vapors with stripping water to provide stripping water vapors and stripping water at at least about the boiling point of water; (b) passing the stripping water vapors from step (a) to a steam ejector; (c) passing the stripping water from step (a) to a motive steam generator wherein the stripping water is vaporized under pressure; (d) passing the stripping water vapors from step (c) to the steam ejector referred to in step (b); and (e) passing the stripping water vapors, introduced into the steam ejector in accordance with steps (b) and (d), to the lower half of the distillation zone.

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 hydrocarbon feed material for fuel purposes.

Abstract: The number of beds on the adsorption step of a pressure swing adsorption cycle is varied cyclically throughout the cycle. As a result, the final bed repressurization step is separated from the partial repressurization-pressure equalization step, thereby enhancing product recovery, without discontinuity in the flow of product effluent from the adsorption system or the use of an external repressurization storage tank.

Abstract: Ethanolamine is subjected to reductive amination in a continuous process to produce diethylenetriamine with less than 10 weight percent piperazine contained in the reaction products. The reductive amination conditions include the use of a catalyst, an ethanolamine feed rate of at least about 400 kilograms of ethanolamine per hour per cubic meter of catalyst, and a temperature sufficient to react between about 35 and 60 percent of the ethanolamine fed.

Abstract: In the purification of gas streams by contact with a permeable membrane selective for the separation of desired components from impurities, harmful gas stream components are removed by means of a pressure swing adsorption system prior to passage of said gas streams to the permeable membrane. Where the harmful components nevertheless comprise valuable components of said gas streams, the purified portion of said gas stream, either the permeate or the non-permeate from said membrane, is used to supply purge gas to the pressure swing adsorption system for desorption and recovery of said harmful components together with said desired components purified upon contact with said membrane.

Abstract: This invention relates to low shrinking, low viscosity curable polyester resin compositions, which compositions contain a mixture of (i) an unsaturated ester terminally modified with a reactive olefin such as dicyclopentadiene or other Diels-Alder adducts of cyclopentadiene with an olefinic or acetylenic hydrocarbon or alkylated derivative thereof, (ii) a copolymerizable ethylenically unsaturated monomer which serves to crosslink the unsaturated polyester to a thermoset product, and (iii) a thermoplastic polymer low profile additive. Cured articles prepared from these curable polyester resin compositions exhibit reduced surface roughness. Fiber reinforced thermoset articles can be produced from these curable resin compositions.

Abstract: Described herein are compositions which contain a specific group of oligomeric diamine hardeners and epoxy compounds which when combined with structural fibers produce composites which have improved tensile properties, high compressive strengths, and improved impact resistance. These compositions also exhibit low moisture absorption.

Abstract: Described herein is a composition comprising a select group of substituted diamine hardeners and an expoxy resin containing two or more 1,2-epoxide groups per molecule. These compositions exhibit reduced moisture absorption, and controlled reactivity which comprises the processing characteristics of the composition.