Canadian Liquid Air Ltd - Air Liquidecanada Ltee

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Canadian Liquid Air Limited

Canadian Liquid Air Ltd./air Liquide Canada

American Air Liquide, Inc.

Canadian Liquid Air/air Liquide Canada Ltee

Derek Hornsey

Robert G Lee

Guy Savard

V S Meenakshi Sundaram

Jose M Dieguez

Steven A Fisher

Sebastien Corbeil

John R Ayton

Guillermo F Garrido

Gordon H Homer

Arthur S Perkins

Michel Epiney

Sebastien Corbiel

Provided is a process for bleaching pulp with ozone. The process involves preparing a slurry of cellulosic pulp having a consistency in fibers of from 1-5 weight %. Such a low consistency slurry is then mixed with ozone under high shear conditions. The ozone is then maintained in contact with the cellulosic fibers to effect bleaching of the fibers. The present process offers the advantages of bleaching using a low consistency slurry, with the added advantages of employing ozone.

Ozone bleaching of low consistency pulp

Provided is a process for bleaching pulp with ozone. The process involves preparing a slurry of cellulosic pulp having a consistency in fibers of from 1 up to 5 weight %. Such a low consistency slurry is then mixed with high partial pressure ozone under high shear conditions. The ozone is then maintained in contact with the cellulosic fibers to effect bleaching of the fibers. The present process offers the advantages of bleaching using a low consistency slurry, with the added advantages of employing ozone.

Process for the bleaching of low consistency pulp using high partial pressure ozone

Process for ozone bleaching of low consistency pulp

A method of bleaching a pulp at low consistency employs chlorine dioxide and/or chlorine, to partially bleach the pulp. The aqueous partially bleached pulp flows along a sinuous flow path providing a high ratio of flow path of aqueous pulp to length of effective travel of the aqueous pulp. Ozone is introduced to the aqueous pulp at spaced apart locations in the flow path so that a low partial pressure of ozone is established in the flow path which favors chemical oxidation of the lignin and low chemical attack on cellulose. In this way effective bleaching is achieved with reduced use of chlorine or chlorine dioxide and reduced production of chlorinated compounds.

Method for ozone bleaching of cellulosic pulp at low consistency

A method and installation for bleaching a lignocellulosic pulp with ozone, while recovering an oxygen-rich gas which may be recycled or re-used. Bleaching of the pulp with ozone is preferably carried out under conditions in which ingress of air is prevented. In a multi-step bleaching process, an oxygen-rich vent gas typically containing at least 90%, by weight, of oxygen may be recovered from a second contactor for potential use in different oxygen-consuming operations in a pulp mill.

Method of monitoring and recovering oxygen-rich gas from ozone bleaching

In the non-acidic sizing of paper reaction between alkylketene dimer sizing agent and cellulose of cellulosic paper-making fibers is catalyzed by dissolving carbon dioxide in an aqueous vehicle of an aqueous pulp of the paper-making fibers; the carbon dioxide provides bicarbonate ions which catalyse the reaction; the bicarbonate ions may be generated by dissociation of the carbon dioxide in water, or by reaction of the carbon dioxide with calcium carbonate incorporated in the pulp as a filler for the paper, or with some other alkali present.

Carbon dioxide in neutral and alkaline sizing processes

A process and apparatus for leaching metal values from a particulate mineral ore containing metal values employs a fluidized bed of the particles; a leaching agent solution containing dissolved oxygen flows upwardly of the bed in a lower leaching zone, to an upper clarification zone; a velocity profile is maintained to promote settling of particles so that the particulate solids remain in the leaching zone and a clarified leachant-containing liquid low in suspended solids rises and collects in the clarification zone; the process is carried out with a minimum of undissolved gas and avoids the need for mechanical agitation, but the kinetics of the chemical leaching reaction is improved and heat loss via escaping gases is avoided.

Hydrometallurgical leaching process and apparatus

A gas, for example, oxygen which has low solubility in water is efficiently dissolved and reacted with a substance in a flowing liquid medium by injecting the gas into the flowing liquid at spaced apart points such that a bubble flow condition is maintained and the injected gas is dissolved and substantially consumed by reaction with the substance in the interval between adjacent injection points; in this way the gas is injected at a point at which the aqueous liquid has maximum dissolving capacity and the number of injection points can be minimized; in another embodiment oxygen injection is controlled to maintain a desired oxygen:liquid ratio effective for efficient dissolving of the oxygen while maintaining the bubble flow condition, however, this requires more injection points.

Pipeline reactor and method

An inert gas such as helium is employed as a tracer gas in a pulp and paper mill to determine the utilization of oxygen by an aqueous cellulosic pulp particularly, as well as other parameters, in an oxygen delignification or extraction in which oxygen is dissolved in the pulp and reacted to solubilize lignins and reduce the requirement for chlorine-based bleaching chemicals.

Apparatus and method for measuring vent gas flow rates and parameters in

Oil is recovered from an underground formation by the use of steam and a gas rich in oxygen. In a priming stage, high quality saturated steam or superheated steam is injected into the formation to raise the reservoir temperature, in the vicinity of injection, to the combustion temperature of the oil. Then, in a combustion stage, the injection of steam is continued and oxygen-containing gas is injected as well, so that local combustion of oil occurs. This results in further heating of the steam and the generation of hot combustion gases, increasing the mobility of the oil and creating pressure drive. The priming and combustion stages may be part of a cyclic steam stimulation ('huff and puff') method or a steam flooding method. Special expedients are provided for the safe use of oxygen and steam.

Process and device for oil recovery using steam and oxygen-containing gas

In a steam generating boiler having a bottom wall supporting a char bed and sidewalls with ports through which air is admitted for combustion of combustible species in the char bed and emanating therefrom, combustion is improved by introducing an oxygen-containing gas into a lower central zone of the boiler, from at least one point remote from the sidewalls to thereby cause intimate mixing of the oxygen contained in the gas with the combustible species.

Non-peripheral blowing of oxygen-containing gas in steam generating

A biological waste water treatment carried out in a single tank. The conditions in the tank are controlled to provide a biological reaction zone containing waste water and biodegrading organisms and an overlying clarification zone from which an effluent of treated waste water flows. The recycle stream is continuously withdrawn from the biological reaction zone, supplemented with influent waste water, passed through an oxygen-dissolving device, and the supplemented stream returned to the reaction zone. The oxygen is monitored and supplied to satisfy the demands of the organisms and, at the same time, to keep the oxygen in solution. The supplemented recycle stream is continuously injected along the bottom of the biological reaction zone in a horizontal shallow inflow having a width substantially greater than its depth and a flow considerably greater than that of the influent. And, the recycle stream is withdrawn from near the bottom of the reaction zone, at a vicinity remote from the inflow, in an outflow having a substantially greater width than its depth. In this way there is created between the inflow and the outflow a horizontally relatively fast flowing undercurrent having an extensive uninterrupted interface with an overlying relatively quiescent body of mixed liquor flowing upwardly relatively slowly.

Two zone apparatus for biological treatment of waste water

A biological waste water treatment carried out in a single tank. The conditions in the tank are controlled to provide a biological reaction zone containing waste water and biodegrading organisms and an overlying clarification zone from which an effluent of treated waste water flows. The recycle stream is continuously withdrawn from the biological reaction zone, supplemented with influent waste water, passed through an oxygen-dissolving device, and the supplemented stream returned to the reaction zone. The oxygen is monitored and supplied to satisfy the demands of the organisms and, at the same time, to keep the oxygen in solution. According to the invention, the supplemented recycle stream is continuously injected along the bottom of the biological reaction zone in a horizontal shallow inflow having a width substantially greater than its depth and a flow considerably greater than that of the influent. And, the recycle stream is withdrawn from near the bottom of the reaction zone, at a vicinity remote from the inflow, in an outflow having a substantially greater width than its depth. In this way there is created between the inflow and the outflow a horizontally relatively fast flowing undercurrent having an extensive uninterrupted interface with an overlying relatively quiescent body of mixed liquor flowing upwardly relatively slowly.

Two zone process for biological treatment of waste water

An apparatus is provided for treating waste water biologically and clarifying the biologically treated water; considerable economic advantage is obtained by conducting both the biological treatment and the clarification of biologically treated water in a single vessel rather than in separate vessels; it is further found possible to treat in this system water containing much higher concentrations of waste; in the process the supply of oxygen to the biological reaction zone is carefully monitored to meet the biological oxygen demand and avoid the occurrence of undissolved oxygen in the form of gas bubbles in the biological reaction zone or the clarification zone; there is further provided improvements in oxygen dissolving devices rendering them especially suitable for the two zone treatment.

Apparatus for biological treatment of waste water

A process is provided for treating waste water biologically and clarifying the biologically treated water; considerable economic advantage is obtained by conducting both the biological treatment and the clarification of biologically treated water in a single vessel rather than in separate vessels; it is further found possible to treat in this system water containing much higher concentration of waste; in the process the supply of oxygen to the biological reaction zone is carefully monitored to meet the biological oxygen demand and avoid the occurrence of undissolved oxygen in the form of gas bubbles in the biological reaction zone or the clarification zone; there is further provided improvements in oxygen dissolving devices rendering them especially suitable for the two zone treatment.

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Beaconsfield, Canada

Derek Hornsey