Praxair Technology, Inc.

Union Carbide Industrial Gases Technology Corporation

Alan R Barlow

Michael F Riley

Sudhir K Sharma

Mark S Nowotarski

Jaak S Van Den Sype

Ronald Joseph Selines

Paul J Schaffer

Allen H Chan

An endogenerator is provided in which CO and H.sub.2 are generated as primary products of hydrocarbon oxidation. Noble metal catalysts such as platinum (Pt) and particularly rhodium (Rh), are loaded on a porous ceramic support, of example, an alumina carrier. In the endogenerator reactor little or no CO and H.sub.2 are produced by the slow and energy-intensive reforming reactions and this allows for a compact reactor which operates autothermally without auxiliary heating means, and with high space velocities wherein space velocity is defined as the number of standard cubic feet per hour of output gas per cubic foot of the catalyst carrier. Preferred hydrocarbons are methane or propane, preferred oxidants are nitrogen/oxygen mixtures with from 5% oxygen up to 100% oxygen. The endogenerator of the present invention provides a process and apparatus that generates the required reducing gases CO and H.sub.2 for heat treating applications which require leaner atmospheres and lower carbon potentials. The present invention provides a reactor which operates autothermally and in which very high space velocities are achieved. The reactors of the present invention also provide inexpensively the reducing elements required to obtain buffered atmospheres in heat treating furnaces and thereby allow the introduction of inexpensive nitrogen produced by membranes or PSA into such furnaces.

Process and apparatus for producing heat treatment atmospheres

An apparatus and method for providing a selected atmosphere at and within an opening to the interior volume of a furnace. Two or more paralleled diffusers adjacent to the furnace opening laminarly emit different fluids and provide a multilayer fluid curtain over the opening. The curtain has a composite modified Froude number from 0.05 to 10, and a thickness at emission of at least 5% of its extent in the flow direction. Partially covering the outside of the curtain is an optional, substantially flat, outer shield with an aperture coinciding with the furnace opening, which reduces the necessary flow rates of fluids. Optional side shields around the sides of the curtain also reduce the necessary fluid flow. A preferred diffuser comprises a porous tube in a housing with an outlet directed to emit fluid across the furnace opening. The outlet is covered with a screen to disperse the fluid flow and to protect the porous tube.

Multi-layer fluid curtains for furnace openings

An apparatus and method for providing a selected atmosphere at and within an opening to the interior volume of a furnace. Two or more paralleled diffusers adjacent to the furnace opening laminarly emit different fluids and provide a multi-layer fluid curtain over the opening. The curtain has a composite modified Froude number from 0.05 to 10, and a thickness at emission of at least 5% of its extent in the flow direction. Partially covering the outside of the curtain is an optional, substantially flat, outer shield with an aperture coinciding with the furnace opening, which reduces the necessary flow rates of fluids. Optional side shields around the sides of the curtain also reduce the necessary fluid flow. A preferred diffuser comprises a porous tube in a housing with an outlet directed to emit fluid across the furnace opening. The outlet is covered with a screen to disperse the fluid flow and to protect the porous tube.

A tuyere and method for discharging an agitating gas into the molten contents of an electrically heated furnace to reduce temperature and composition variations in its contents. The tuyere comprises a refractory plug and sleeve for installation into the refractory wall and shell of the furnace, and a dielectric section in the tuyere pipe outside the furnace shell to prevent electrical arcing and current flow into the gas supply piping and external supports.

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Stamford, CT, United States of America

Alan R Barlow