L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des

Other

American Air Liquide, Inc.

Air Liquide America, L.p.

Sogemi - Societa Generale Macchine Impianti

Jansen Combustion and Boiler Technologies, Inc.

Eric L Duchateau

Philippe Queille

Yannick Rancon

Arie Verloop

Louis C Philippe

Edward C Dye

David R Scheeff

Pierre Karinthi

Thierry Sindzingre

Pierre Claverie

Sylvie Mellul

Olivier Charon

Jean-Pierre Zumbrunn

Eberhard Kloers

Sophie Drogue

Tom Nilsson

Pascal Baldo

Benoit Lhote

Angelo Vigorelli

Methods of increasing the throughput of recovery boilers equipped with at least three levels of injection of air with oxygen enrichment of the air in at least one air level. In one method, a black liquor recovery boiler has three levels of air injection, and oxygen enrichment is applied to at least the secondary and the tertiary air injection levels. In another method, a black liquor recovery boiler has four levels of air injection, and oxygen enrichment is applied to one or more of the tertiary or quaternary air injection levels. In another method, a black liquor boiler has three levels of air injection, with oxygen enrichment applied to at least two air injection levels. After combustion, the oxygen concentration in the resultant flue gas is sensed. The oxygen injection is then adjusted in order to maintain the sensed oxygen concentration at the previously selected oxygen set point.

Methods of improving productivity of black liquor recovery boilers

Methods are presented to increase the throughput of a recovery boiler equipped with at least primary and secondary levels of injection of air. The methods comprise operating the recovery boiler with a third level of oxidant injection below or at the same level as the secondary level, and oxygen enrichment applied to at least the secondary level and said third level.

Methods of increasing the throughput of recovery boilers equipped with at least two levels of injection of air, the methods improving the thermal efficiency of the boiler with oxygen enrichment of the air in at least one level of the combustion air system, at or above the secondary air level. In one method, a black liquor recover boiler having two levels of air injection is retrofitted with a third level of oxidant injection below or at the same level as the original secondary air, and oxygen enrichment is applied to at least the original secondary air stream and the third level air stream. A preferred method is for the third level to be placed at or close to the same level as the black liquor injector ports.

A process for the vitrification of products in the form of solid pieces or particles without the release of dust as a pollutant, according to which there is used a furnace (3) provided with a burner (15). There are introduced into the furnace the products to be vitrified, and the products are permitted to heat in the furnace until they form a liquid or pasty vitreous mass, then this vitreous mass is removed from the furnace and permitted to cool. The internal walls of the furnace are preheated with the burner to a temperature exceeding the temperature at which the products to be vitrified can form a liquid or pasty vitreous mass, then the energy supplied by the burner is reduced substantially or even cut off, before introducing waste into the furnace. The products are heated principally by receiving the heat transmitted from the internal walls of the furnace until all of the product is in the form of a liquid or pasty mass, the burner being maintained at reduced power or even shut off at least until this time. Then the products are discharged from the furnace. If desired, when all of the product has achieved the form of a pasty mass, the power of the burner is again increased until the product will be fairly fluid to permit its easy evacuation.

Process for the vitrification of products in the form of solid pieces or

A process for combustion in an industrial furnace (1), using at least one burner (2; 3) supplied with combustible (4) and combustion supporting (5) fluids. The flow rate of at least one of the fluids is pulsed at a frequency comprised between 0.1 and 3 Hz. There is provided in the furnace (1) at least one pair of two burners (2A, 2B; 3A, 3B) disposed substantially confronting each other; and the fluid of the burners of a pair is pulsed in offset phase from one burner to the other. The frequency of pulsation is between 0.1 and 1 Hz. The flow rates of fluids are substantially identical for each burner (2A, 2B; 3A, 3B) of the pair. The power of the pair of burners is greater than 300 KW.

Process for combustion in an industrial furnace

In a method of dry process fluxing at least one surface of a metallic article, the surface to be fluxed is treated with a plasma at atmospheric pressure of a gaseous mixture comprising hydrogen and optionally at least one inert gas. The invention also concerns an apparatus, particularly for practicing the process, as well as a process for soldering or plating.

Method and apparatus for dry process fluxing

The thermal treatment atmosphere is obtained by catalytic reaction of an impure mixture of nitrogen, advantageously obtained by permeation or adsorption, and hydrocarbon, the catalytic reaction being carried out at a temperature between 400.degree. and 900.degree. C., typically between 500.degree. and 800.degree. C., with a noble metal base catalyst, typically platinum or palladium on alumina support. The reaction may be carried out in a reactor placed inside or outside the furnace.

Process of the production of an atmosphere for the thermal treatment of

Substantially all residual oxidizing gas in a treating atmosphere which is inert or reducing, is eliminated by injecting into the atmosphere a gaseous silicon hydride at a temperature between 50 and 1,600.degree. C. and in amount such that the ratio R of the content of hydride to the content of oxidizing gas to be eliminated is within the range of 1.5 to 20. The rapid action of the trace amounts of hydride injected enables one to control with precision heat treatment processes by maintaining the residual oxidizing gas contents below predetermined very low thresholds.

Processes for the production of a controlled atmosphere for heat

Process for heat treating articles by hardening them in a recirculating gas medium which is in contact with the treated articles, the hardening gas being cooled by means of a heat exchanger, of the type in which helium is used as hardening gas, and is stored under holding pressure in a buffer container, wherein at the end of a hardening operation, a helium load is extracted from the treatment enclosure, in final phase by means of pump until a primary vacuum is obtained, the extracted helium is brought to purifying pressure by means of a compressor associated to a mechanical filter, and the helium under purifying pressure is sent to a purifier in which impurities are removed, after which it is transferred, if desired, after recompression in the buffer container.

Process and apparatus for heat treating articles while hardening in

Heat treating metals by continuous longitudinal passage of metallic pieces in an elongated treating zone under controlled atmosphere having a high temperature upstream end where the controlled atmosphere comprises nitrogen and reducing chemical substances, such as hydrogen, possibly carbon monoxide, and a downstream cooling end under an atmosphere essentially formed by introducing nitrogen. In the high temperature upstream end, the nitrogen which constitutes the atmosphere is supplied by introducing nitrogen with a residual oxygen content not exceeding 5%, the reducing chemical substances being present at any moment in amounts at least sufficient to eliminate oxygen introduced with nitrogen. The nitrogen introduced in the downstream cooling end is substantially free of oxygen. Application of the process to the annealing of metallic pieces.

Process for heat treating metals in a continuous oven under controlled

Process for thermal treatment of metals by passage of metallic pieces into an elongated zone under a controlled atmosphere, having an upstream section at an elevated temperature, where the controlled atmosphere comprises nitrogen and reductive chemicals, particularly hydrogen, possibly carbon monoxide; and a downstream section at a lower temperature under a controlled atmosphere. The invention is characterized by the fact that in the upstream section at an elevated temperature, the atmosphere comprises nitrogen having a residual content of oxygen between 0.5% and 5% produced by separation of air using permeation or adsorption techniques. The reductive chemicals are present at all times in a content at least sufficient to eliminate the oxygen admitted with the nitrogen. The controlled atmosphere in the section downstream from the elongated thermal treatment zone is formed by admission of a gaseous flow taken from the upstream section at an elevated temperature and transferred directly into the downstream section at a lower temperature.

Process for thermal treatment of metals

Process for the heat treatment of low-alloy steels at temperatures higher than 600.degree. C., such as annealing or heating before hardening, etc., said treatment being carried out in a protection atmosphere produced by the injection of nitrogen, hydrocarbon C.sub.x H.sub.y and optionally hydrogen, with a control of the atmosphere. According to the invention, the composition of the residual species CH.sub.4, CO, H.sub.2 O, and the temperature of the gaseous mixture in the furnace are controlled in order to control the carburization and the decarburization of the treated steels.

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Gieres, France

Eric L Duchateau