Apparatus and methods are provided for converting methane in a feed stream to acetylene. A hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process.

Methane conversion apparatus and process using a supersonic flow reactor

Design of a nickel-base superalloy using a neural network

In a process for converting methane to aromatic hydrocarbons, a feed containing methane is supplied to one or more reaction zone(s) containing catalytic material operating under reaction conditions effective to convert at least a portion of the methane to aromatic hydrocarbons; the reaction zone(s) being operated with an inverse temperature profile.

Production of aromatics from methane

The microstructure stability during δ sub-solvus annealing in Inconel 718 was investigated, focusing on the conditions that may lead to the development of very large grains (about 100 μm) in a recrystallized fine grained matrix (4 to 5 μm) despite the presence of second-phase particles. Microstructure evolution was analyzed by EBSD (grain size, intragranular misorientation) and SEM (δ phase particles). Results confirm that, in the absence of stored energy, the grain structure is controlled by the δ phase particles, as predicted by the Smith–Zener equation. If the initial microstructure is strained (e < 0.1) before annealing, then low stored energy grains grow to a large extent, despite the Zener pinning forces exerted by the second-phase particles on the grain boundaries. Those selectively growing grains could be those of the initial microstructure that were the least deformed, or they could result from a nucleation process. The balance of three forces acting on boundary migration controls the growth process: if the sum of capillarity and stored energy driving forces exceeds the Zener pinning force, then selective grain growth occurs. Such phenomenon could be simulated, using a level set approach in a finite element context, by taking into account the three forces acting on boundary migration and by considering a realistic strain energy distribution (estimated from EBSD measurements).

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Selective Growth of Low Stored Energy Grains During δ Sub-solvus Annealing in the Inconel 718 Nickel-Based Superalloy

A new computational tool has been developed to model, discover, and optimize new alloys that simultaneously satisfy up to eleven physical criteria. An artificial neural network is trained from pre-existing materials data that enables the prediction of individual material properties both as a function of composition and heat treatment routine, which allows it to optimize the material properties to search for the material with properties most likely to exceed a target criteria. We design a new polycrystalline nickel-base superalloy with the optimal combination of cost, density, gamma' phase content and solvus, phase stability, fatigue life, yield stress, ultimate tensile strength, stress rupture, oxidation resistance, and tensile elongation. Experimental data demonstrates that the proposed alloy fulfills the computational predictions, possessing multiple physical properties, particularly oxidation resistance and yield stress, that exceed existing commercially available alloys.

Nickel-chromium alloys consisting essentially of from 30-75 nickel, 12-30% chromium, up to 10% molybdenum, up to 8% tungsten, up to 15% cobalt, up to 5% of niobium and/or tantalum, titanium plus aluminum up to 5%, and carbon nitrogen and silicon in correlated percentages to thereby improve low cycle and thermal fatigue strength, the balance being from 0 to 50% iron.

Nickel-chromium alloy of improved fatigue strength

The stress-rupture strength of a nickel-chromium-molybdenum-cobalt alloy is enhanced by reason of a special morphological microstructure which in terms of carbides present is characterized by a predominant amount of the M6C carbide.

Nickel-base alloy

Cobalt-base alloys

A composite tube structure having an inner substrate alloy and an outer, corrosion resistant alloy suitable for use in fluid-bed coal combustion reactors to form a water wall around at least a portion of the periphery of the fluid bed zone. The outer, corrosion resistant alloy centers around a composition of 0.1% carbon, 0.2% silicon, 0.5% manganese, 22% chromium, 3.8% aluminum, 0.4% titanium, 0.05% nitrogen, 0.2% molybdenum, 32% nickel, balance iron.

Alloy for composite tubing in fluidized-bed coal combustor

A mechanically alloyed composition of matter or alloy containing 30-40% chromium, 5-25% cobalt, 0.5-10% iron, 0.2-0.6% aluminum, 0.3-1.2% titanium, up to 0.15% carbon, about 0.2-1% yttria, up to about 0.3% nitrogen, the % titanium being at least about 1.4 times the % nitrogen, minor amounts of optional elements, the balance being essentially nickel. The consolidated and hot worked alloy with coarse grains produced by heat treatment at about 1300° C. is useful in service requiring hot strength along with extraordinary resistance to oxidation, sulfidation and hot corrosive media. Specific utilization of the alloy of the invention is contemplated in handling molten glass and in utensils adapted to be used in contact with molten glass, e.g. spinners.

Gaylord D. Smith

Papers

Nickel-chromium alloy of improved fatigue strength

Nickel-base alloy

Cobalt-base alloys

Alloy for composite tubing in fluidized-bed coal combustor

Mechanically alloyed nickel-cobalt-chromium-iron composition of matter and glass fiber method and apparatus for using same