Abstract: Isobutane in a C.sub.4 hydrocarbon feed stream is converted to methacrolein in an integrated two-step process. Isobutane is dehydrogenated in a first step to isobutylene, hydrogen, and by-products and the reaction effluent is passed directly into a second step where isobutylene is oxidized to methacrolein without significant oxidation of the hydrogen and by-products. Any normal butenes present are converted to butadiene. The methacrolein and by-products may be separated and the unreacted isobutylene and isobutane recycled to the first step. Alternatively, the effluent from the second step may be used as feed to a further oxidation step for conversion of methacrolein to methacrylic acid.

Abstract: A mixing device for combining a quench or catalyst stream with the main fluid stream in an upflow gas-liquid contactor, such as a reactor. A gas-liquid stream is passed through a reduced size passage wherein the quench or catalyst streams are injected. The combined stream then is mixed and redistributed.

Abstract: A process for the liquefaction of natural gas which employs a multi-component refrigerant system and a second independent refrigeration system. The process differs from the prior art processes in that the feed gas is cooled only by the independent refrigeration system until it has been freed of those components which could precipitate as solids at the low temperatures of the liquefaction process and thereafter is cooled by the multi-component refrigeration system. The multi-component refrigerant system is a self-contained cycle and does not reject heat to the independent refrigeration system, but directly to the ambient temperature surroundings.

Abstract: NO.sub.x produced by combustion of nitrogen-containing fuels is reduced by a forced draft burner operating with below stoichiometric mixtures of air and fuel in a primary combustion chamber, combustion being completed by controlled injection of secondary air near the outlet of the chamber.

Abstract: Resistance of iron, iron-chromium and iron-chromium-nickel alloys to corrosive attack by sulfur compounds at temperatures above 500.degree. F. is improved by pretreating the metal under controlled conditions to form an extremely thin submicroscopic oxide film which serves as a corrosion resistant barrier.

Abstract: A self-contained probe for testing of buried pipe by analyzing acoustic emissions produced under increasing stress which comprises an elongated tubular body with a hardened metallic point at one end which is placed against the pipe. The body of the probe also contains an acoustic transducer, a preamplifier, and an integral power supply. The probe receives acoustic emissions from the pipe under test, transforms acoustic signals into electrical voltages, preamplifies those voltages, and transmits them to associated facilities for computer analysis.

Abstract: A wash liquid distributor for a rotary drum filter which distributes liquid uniformly across the filter cake and provides very effective washing. The distributor apparatus in its preferred embodiment comprises an elongated hollow pipe, one or more being used in parallel operation, each pipe having a multiplicity of evenly spaced and axially aligned small holes. Each hole imposes a substantial pressure drop on the fluid passing therethrough and creates a uniform distribution of the wash liquid along the distributor pipe. To avoid damage to the filter cake from the jets of liquid produced, a diffusion channel is provided which damps the kinetic energy of the jets and subdivides the liquid entering the channel. Upon leaving the diffusion channel the liquid is collected and redistributed from drip points spaced at intervals which are generally narrower than those of the holes in the distributor pipe.

Abstract: A method and apparatus for measuring particulates contained in the exhaust gases from internal combustion engines which dilutes the exhaust gases with prefiltered and precooled air to produce a constant volume mixture which may be sampled for exhaust gas emissions as well as for particulates. After mixing of the exhaust gases and the pretreated air, sampling of the mixture by isokinetic probes produces a uniform sample of particulate matter which is collected on temperature controlled filters for analysis.

Abstract: A trough-type scale trap for use with a refinery or chemical plant reactor having a catalyst bed subject to plugging by fine particles. Compared to prior art traps, the trough-type scale trap of the invention is characterized by a larger volumetric capacity and screen area and is substantially easier to construct and to install or remove from closed reactor vessels than conventional traps. Its typical embodiment is as a series of parallel troughs having rectangular openings and disposed chordally across the reactor normal to the direction of flow. In one embodiment, the trough is a rectangular parallelepiped; in another embodiment, the substantially rectangular opening is reduced by tapering to a bottom significantly smaller than the inlet opening.