Kamyr, Inc.

Ahlstrom Machinery, Inc.

Other

Andritz Inc.

J Wayne Chamblee

C Bertil Stromberg

Bruno S Marcoccia

J Robert Prough

Rolf C Ryham

Erwin D Funk

Eskil L Karlson

Jerry R Johanson

Brian F Greenwood

R Fred Chasse

Louis O Torregrossa

John D Weston

Jay J Miele

Marco Marois

Gunther Plattner

Chemical cellulose pulp is made from sawdust utilizing a static down-flow retention vessel. By adding steam and cooking liquor to a flow of sawdust a heated slurry, at a cooking temperature of about 250-350&deg; F., is produced. The heated slurry is, at superatmospheric pressure, moved downwardly in the static down-flow retention vessel while cooking temperature is maintained, for a time period of about 0.5-6 (preferably 1 to 3) hours, the slurry having a consistency of about 5-30%. At superatmospheric pressure, without significant reduction in pressure from the retention vessel, the slurry is cooled to well below cooking temperature by diffusing cooling liquid through it, as in a conventional pressure diffuser. The discharge from the retention vessel is preferably substantially solely gravity action (e.g. using a discharge with single convergence and side relief). Various mixing, diluting, thickening, steaming, and pumping devices are utilized in the system from initial steaming of the sawdust to passage into the top of the retention vessel.

Apparatus for pulping sawdust

A system and method for feeding comminuted cellulosic fibrous material such as wood chips to the top of a treatment vessel such as a continuous digester provide enhanced simplicity, operability, and maintainability by eliminating the high pressure transfer device conventionally used in the prior art. Instead of a high pressure transfer device the steamed and slurried chips are pressurized using one or more slurry pumps located at least thirty feet below the top of the treatment vessel and for pressurizing the slurry to a pressure of at least about 10 bar gauge. A return line from the top of the digester may, but need not necessarily, be operatively connected to the one or more pumps and if connected to the pumps the pressure in the return line may be reduced utilizing a pressure reduction valve and/or a flash tank. During pressurized transferring of the slurry from the pumps to a treatment vessel (which may be as little about 10 feet or as much as about a half a mile away) treatment liquid is provided which contains at least some active pumping chemical including sodium hydroxide, sodium sulfide; polysulfide, anthraquinone or their equivalents or derivatives; surfactants, enzymes, or chelants; or combinations thereof. Pseudo-countercurrent circulation of treatment liquids may be provided between stations.

Method for feeding comminuted fibrous material

A number of distinct parallel digesters are fed with chips from a common steaming vessel. After steaming the chips are slurried and pressurized, and substantially simultaneously the steamed, slurried, and pressurized chips are transferred to at least some of (and typically each of) the distinct parallel digesters. A material stream is split into a number of individually controllable material streams (one for each of the digesters) either at the discharge from the steaming vessel, after slurrying (or at the discharge from a slurrying vessel), or after pressurizing (e.g. in a high pressure transfer device). For example a multi-branch conduit may be connected to the slurry outlet from the high pressure transfer device, the conduit having a branch directly connected to each of the digesters. A distinct return conduit may also be provided from each of the digesters to the high pressure transfer device, each return conduit preferably has a distinct flow control device and/or pump which are individually controlled.

Method and apparatus for feeding multiple digesters

A system and method for feeding comminuted cellulosic fibrous material such as wood chips to the top of a treatment vessel such as a continuous digester provide enhanced simplicity, operability, and maintainability by eliminating the high pressure transfer device conventionally used in the prior art. Instead of a high pressure transfer device the steamed and slurried chips are pressurized using one or more slurry pumps located at least thirty feet below the top of the treatment vessel and for pressurizing the slurry to a pressure of at least about 10 bar gauge. A return line from the top of the digester may, but need not necessarily, be operatively connected to the one or more pumps and if connected to the pumps the pressure in the return line may be reduced utilizing a pressure reduction valve and/or a flash tank. Steam from the flash tank may be used in steaming the chips. Pressure relief prevention may be provided by isolation valves in the lines leading to and from the top of the treatment vessel controlled by a controller which is responsive to the pressure sensed in the slurry line leading to the top of the treatment vessel.

Method and system for feeding comminuted fibrous material

A continuous digester discharges pulp without mechanically engaging the pulp, by using one or more discharge transitions with one dimensional convergence and side relief. The transitions may be mounted within a pre-existing digester shell (after removal of the discharge rotor), and supported by a number of braces and/or a skirt shaped like a truncated cone. The operation of a digester, or other continuous vessel, may be controlled by automatically sensing the level of comminuted cellulosic fibrous material in the vessel and automatically controlling the introduction of dilution liquid into the vessel to discharge the material from the vessel in response to the sensing.

Discharge from pulping vessels without the aid of mechanical agitation

An ozone generator has one or both of the tube type electrodes coated with a dielectric that has high dielectric strength, high dielectric constant, and low piezoelectric activity, and can be applied with a small thickness (less than 0.5 mm). The dielectric has a mixed oxide composition having a dielectric strength of at least about 800 volts/mil, has a dielectric constant that is at least 200, and has low enough piezoelectric activity that it will not ablate, crack, or other otherwise suffer damage as a result of high voltage application over months of use. A metal electrode for use in an ozone generator has a dielectric coating on a surface thereof having a composition comprising: about 30-70% lead oxide, about 2-8% barium oxide, about 2-12% lanthanum oxide, about 3-18% titanium dioxide, about 12-40% zirconium dioxide, and trace materials. A method of coating a metal electrode for use in an ozone generator may include plasma spraying (and the steps leading up to effect of plasma spraying), or dip or spin coating followed by sintering.

Dielectric coating for ozone generator electrodes

Ozone is generated from an oxygen-containing gas utilizing a tube-type ozone generator at significantly greater power efficiency. The oxygen is introduced into the annular passageway between the electrodes of the tube-type ozone generator at an angle (e.g. about 45.degree.-90.degree.) so that it swirls in a cyclonic flow path as it travels from one end of the annular passageway to the other. The amount of power consumed to produce a gas having about 8% ozone is roughly half of the power needed if the same conditions are applied but the oxygen gas is introduced conventionally (without swirling action, so that it travels along the dimension of elongation of the passageway). The swirling action also allows a higher concentration of ozone (e.g. 10% or more) to be achieved in the product gas compared to the same conditions when no swirling is employed. Cooling fluid, such as nitrogen gas, may be passed through an interior passageway and outside the outer electrode either co-current or countercurrent to the general direction of oxygen gas flow.

Swirl flow ozone generating

Liquid process streams--such as white water, pressate, or washer filtrate from a pulp and paper mill--are clarified in an efficient manner using a gas sparged hydrocyclone, which takes up a minimum of floor space. A liquid stream having a consistency of less than about 0.5% solids is introduced into a first end of a vortex. Gas is sparged into the liquid in the vortex to cause particles to attach to gas bubbles and move through a rejects outlet at the first end of the vortex, while clarified liquid is removed from a second end of the vortex. A pedestal is typically provided at the accepts outlet, having a radial clearance with the inside of a porous tube through which the gas is sparged that is about 8-12% the radius of the porous tube.

Growing community of inventors

Queensbury, NY, United States of America

J Wayne Chamblee