2091results about How to "Low selectivity" patented technology

A process for selective formation of ethanol from acetic acid includes contacting a feed stream containing acetic acid and hydrogen at an elevated temperature with catalyst comprising platinum and tin on a high surface area silica promoted with calcium metasilicate. Selectivities to ethanol of over 85% are achieved at 280° C. with catalyst life in the hundreds of hours.

The present invention discloses fluoropolymer coated membranes and methods for making and using these membranes. The fluoropolymer coated membranes described in the current invention are prepared by coating a porous asymmetric membrane layer with a thin layer of fluoropolymer coating. The porous asymmetric membrane layer comprises an asymmetric cellulosic membrane, an asymmetric polymer membrane, or an asymmetric molecular sieve/polymer mixed matrix membrane with a low selectivity and high permeance. The fluoropolymer coating improves the selectivity of the porous asymmetric membrane layer and maintains the membrane performance with time. The fluoropolymer coated membranes are suitable for a variety of liquid, gas, and vapor separations such as desalination of water by reverse osmosis, non-aqueous liquid separation such as deep desulfurization of gasoline and diesel fuels, ethanol/water separations, pervaporation dehydration of aqueous/organic mixtures, CO₂/CH₄, CO₂/N₂, H₂/CH₄, O₂/N₂, olefin/paraffin, iso/normal paraffins separations, and other light gas mixture separations.

This invention relates to methods for reacting a hydrocarbon, molecular oxygen, and optionally water and/or carbon dioxide, to form synthesis gas. The preferred embodiments are characterized by delivering a substochiometric amount of oxygen to each of a multitude of reaction zones, which allows for optimum design of the catalytic packed bed and the gas distribution system, and for the optimization and control of the temperature profile of the reaction zones. The multitude of reaction zones may include a series of successive fixed beds, or a continuous zone housed within an internal structure having porous, or perforated, walls, through which an oxygen-containing stream can permeate. By controlling the oxygen supply, the temperatures, conversion, and product selectivity of the reaction can be in turn controlled and optimized. Furthermore the potential risks of explosion associated with mixing hydrocarbon and molecular oxygen is minimized with increased feed carbon-to-oxygen molar ratios.

A concurrent on-line analytical processing (OLAP)-oriented database query processing method is described, for performing, on the basis of predicate vector-based memory OLAP star-join optimization, concurrent OLAP query processing based on a batch query predicate vector bit operation. The concurrent query processing optimization technology is implemented for I/O performance and parallel OLAP processing performance in a database management system, and setting of concurrent OLAP processing load in an optimized way catering to the I/O performance is supported, thereby improving predictable processing performance oriented to diversified OLAP queries and implementing concurrent query star-join bitmap filtering processing based on predicate vector arrays.

The present invention provides methods, systems and apparatus in which one fluid passes through an orifice or orifices and mixes with another fluid as it flows through a microchannel.

A catalyst for preparing low-carbon olefins by one-step conversion of synthetic gas and a preparation method thereof relate to catalysts; the catalyst is made from 20-60% of a zirconium-based solid solution,30-70% of a double-micropore zeolite molecular sieve and 0.1-10% of metal oxides; the preparation method comprises: adding salt compounds of at least one element from IA, IIIA, VIIB, IB, IIB and the like into deionized water or alcohol to obtain solution A having a mass concentration of 0.1-15%; adding the zirconium-based solid solution into the solution A, heating, drying by distillation, and drying to obtain solid powder; adding the solid powder and the double-micropore zeolite molecular sieve into ethylene glycol, ultrasonically dispersing, and moving a filtered and washed sample to a vacuum drying box, drying at 50-100 DEG C for 2-24 h, calcining in a muffle furnace, and tableting obtained solid sample to obtain the catalyst.

Provided are a photonic crystal type color filter and a reflective liquid crystal display (“LCD”) device having the same. The photonic crystal type color filter includes a substrate, and a photonic crystal disposed on the substrate and having a two-dimensional (2D) grating structure.

A quadrifilar antenna having helical windings is fed by a phase shift feed network, each winding having an open circuit termination element, the phase shift feeding network having forward directional phase shift paths from a feed input to phase shift feed output ports, and having a first reverse directional transmission path from one or more of the phase shift feed output ports back to a first isolation port, and a second reverse directional transmission path from another one or more of the phase shift feed output ports back to a second isolation port, the first and second isolation ports isolated from the forward directional phase shift paths, and a differential termination impedance, floating from ground, connected the first and second isolation ports. Optionally, the differential termination impedance is frequency selective.

The invention provides a cobalt-based compounded catalyst and preparing method and application thereof, comprising a carrier component and a metal component; the carrier uses spherical powder Al2O3; the metal component comprises a first metal component Co; a second metal component is one of Ce, La and Zr; a third metal component is one of Pt, Ru, Rh and Re; the weight percentage of each metal component in the finished catalyst is as follows: the first metal component is 10-35%; the second metal component is 0.5-10%; the third metal component is 0.05-3%; and the rest is aluminum oxide carrier. The invention is cobalt-based compounded catalyst with the diesel oil and paraffin as the main products; and the catalyst is applied for slurry bubble column reactor or continuous-stirring reactor with simple preparing method, less selectivity in methane, high reacting activity and good selectivity in C5+.

The invention relates to a chemical reactor with a nanometric superstructure, comprising at least one member wherein at least one reaction chamber is arranged, and said reaction chamber being filled at least partially with a high specific surface area material having a specific surface area greater than 5 m²/g, and characterised in that said high specific surface area material is selected from nanotubes or nanofibres.

These nanotubes or nanofibres are preferably selected in the group consisting of carbon nanofibres or nanotubes, β-SiC nanofibres or nanotubes, TiO₂ nanofibres or nanotubes.

They may be deposited on an intermediate structure selected in the group consisting of glass fibres, carbon fibres, SiC foams, carbon foams, alveolar β-SiC foams, said intermediate structure filling the reaction chamber of said reactor at least partially.

This invention relates to a process for preparing 4-nitrodiphenylamine and 4-nitrosodiphenylamine to be used for 4-aminodiphenylamine as an intermediate of antiozonant, wherein carbanilide is reacted with nitrobenzene in the presence of an appropriate base, while simultaneously adding aniline to the mixture so as to regenerate some amounts of carbanilide as a starting material. According to this invention, 4-nitrodiphenylamine and 4-nitrosodiphenylamine can be prepared in a higher selectivity and conversion rate via a continuous reaction by recycling carbanilide, a starting material, while adding a certain amount of aniline during the process. Further, the amount of waste water can be significantly reduced compared to the conventional method without any corrosive materials harmful to the environment.

The invention relates to a comprehensive recovery process for lithium-containing polymetallic ores with associated fine-grained niobium-tantalum. The process comprises the steps of raw ore crude grinding, settlement for desliming, flotation, agglomeration and magnetic separation, gravity separation and the like. The process provided by the invention is particularly applicable to the comprehensive recovery of lithium-containing polymetallic ores which contain a great amount of slime, are located in mining areas at low temperature all through the year, are low in grade of associated niobium-tantalum minerals and are fine in disseminated grain size, the process is advanced, reliable, simple, reasonable and highly targeted, the requirement on raw ore grinding fineness is not high, the regrinding amount is small, the operation cost is low, the comprehensive recovery rate is higher and the industrialization prospect is good.

An improved process and system for the endothermic dehydrogenation of an alkane stream is described. The process and system of the present invention comprise a back-mixed fluidized bed reactor. The alkane stream is dehydrogenated in a single reactor stage by contacting the alkane stream with a back-mixed fluidized bed of catalyst. Deactivated catalyst is withdrawn from the back-mixed fluidized reactor and heated to produce hot regenerated catalyst. The hot regenerated catalyst is returned to the back-mixed fluidized bed reactor at a rate sufficient to maintain the back-mixed fluidized bed reactor at substantially isothermal conditions.

Catalysts, catalyst systems, and methods for removing ammonia and/or carbon monoxide in flue gases are provided where ammonia is used with a selective catalytic reduction catalyst for reducing oxides of nitrogen. A dual oxidation catalyst generally comprises an alkali component, a transition metal, and a metal oxide support. This catalyst is also substantially free from precious metal components and effective for substantially simultaneously oxidizing ammonia (NH₃) and carbon monoxide (CO) when placed in an exhaust gas stream. The catalyst is effective to provide low ammonia to nitrogen oxides selectivity.

A Fe-based catalyst for the Fischer-Tropsch synthesis contains Re2O3, Fe3O4, La2O3, CuO, K2O and SiO2. It is prepared through using oxidant to oxidize partially the ferrous sulfate to obtain the mixed solution of iron sulfate and ferrous sulfate, mixing with the mixed solution of lanthanum nitrate and copper salt, fast depositing by alkaline compound, washing the deposited slurry, adding potassium silicate-water glass solution, and spray drying.

A process is provided for the epoxidation of an olefin comprising the steps of: contacting a feed comprising an olefin and oxygen with a catalyst comprising a silver component deposited on a fluoride-mineralized carrier; and producing a product mix comprising an olefin oxide, wherein the partial pressure of olefin oxide in the product mix is greater than about 60 kPa. A process is provided for the epoxidation of an olefin comprising the steps of: contacting a feed comprising an olefin and oxygen with a catalyst comprising a silver component and a high-selectivity dopant deposited on a fluoride-mineralized carrier; and producing a product mix comprising an olefin oxide, wherein the partial pressure of olefin oxide in the product mix is greater than about 20 kPa.

The invention relates to a selective hydrodesulfurization catalyst contains cobalt and molybdenum as active components. The selective hydrodesulfurization catalyst is characterized in that silicon oxide and aluminum oxide are used as carriers of the catalyst; based on the total weight of 100%, the catalyst comprises 2-6wt% of cobalt oxide, 9-15 wt% of molybdenum oxide, 2-8wt% of alkaline earth metal oxide, 2-6wt% of phosphorus oxide, 3-5wt% of alkali metal oxide, 2-6wt% of silicon oxide and 54-80 wt% of aluminum oxide; and the catalyst has the specific surface area of 200-300m<2>/g and the pore volume of 0.5-0.7mL/g. The catalyst has high hydrogenation activity and selectivity, good stability, low research octane number loss and high liquid yield. The catalyst is suitable for selective hydrodesulfrization of low-quality gasoline and is particularly suitable for selective hydrodesulfrization of low-quality FCC (Family Car China) gasoline.