Assignee: Andritz-Ahlstrom Inc.

Location: GlensFalls, NY
No. of patents: 28

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Number	Title	Issue Date
6375795	Minimization of malodorous gas release from a cellulose pulp mill feed system The release of malodorous TRS-containing gases from a comminuted cellulosic fibrous material feed system for a digester is minimized utilizing a particular arrangement associated with a pressure isolation device. Material is fed through the pressure isola...	04/23/2002
6346166	Flash tank steam economy improvement By the utilization of a jet ejector (such as a thermocompresser) in a cellulose chemical pulp mill, it is possible to effectively increase the utilization of steam. The volume of steam from a flash tank which flashes black liquor from a pulp digester may ...	02/12/2002
6346167	Dissolved solids control in pulp production Kraft pulp of increased strength and bleachability may be produced with decreased consumption of effective alkali, and at a lower H factor, by keeping the dissolved organic material (DOM) concentration low substantially through the entire kraft cook, incl...	02/12/2002
6344112	Screen having inclined slots for a digester A screen used in the production of cellulose pulp may be mounted in a digester to minimize traditional screen problems (including clogging) without introducing new problems. The screen comprises a screen plate having a plurality of slots formed in it with...	02/05/2002
6336573	Hopper, or bin, screw feeder construction controlling discharge velocity profile A bin or hopper, preferably with one-dimensional convergence, has a slot outlet at its bottom for discharging bulk solid particulate material (such as coal, wood chips, sugar, plastic pellets, etc.) to a screw in a trough. The screw has varying flight dia...	01/08/2002
6336993	Metal removal from comminuted fibrous material during feeding A system and method for feeding a slurry of comminuted cellulosic fibrous material such as wood chips to the top of a treatment vessel such as a continuous digester also treat the material to remove metals before digestion. During pumping of the slurry wi...	01/08/2002
6332542	Tramp material removal from pulp feed system Dense, tramp material, is efficiently separated in a comminuted cellulosic fibrous material feed system, for example in a chemical cellulose digester feed system, in a simple but effective matter. By merely utilizing a generally vertical conduit and a slu...	12/25/2001
6325890	Feeding comminuted fibrous material 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 transfe...	12/04/2001
6325888	Method for pulping sawdust 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° F., is produced. The heated slurry is, at supe...	12/04/2001
6315128	Tramp material removal from pulp feed systems Dense, tramp material, is efficiently separated in a comminuted cellulosic fibrous material feed system, for example in a chemical cellulose digester feed system, in a simple but effective matter. By merely utilizing a generally vertical conduit and a slu...	11/13/2001
6306252	Heat recovery from spent digester cooking liquor Steam (preferably clean steam) having less noncondensible gases than steam produced by conventional black liquor flashing is produced from hot black liquor from a digester of a pulp mill. A heat exchanger is utilized and the hot black liquor is passed thr...	10/23/2001
6284095	Minimization of malodorous gas release from a cellulose pulp mill feed system The release of malodorous TRS-containing gases from a comminuted cellulosic fibrous material feed system for a digester is minimized utilizing a particular arrangement associated with a pressure isolation device. Material is fed through the pressure isola...	09/04/2001
6280569	Compression rings for column relief in continuous cooking vessels The flow of a liquid slurry of comminuted cellulosic fibrous material (e.g. wood chips) in a vertical vessel is made more uniform by providing a plurality of vertically spaced sets of either substantially continuous or discontinuous protrusions which exte...	08/28/2001
6280568	Dissolved organic material control in a cellulose pulp continuous digester Kraft pulp of increased strength and bleachability may be produced with decreased consumption of effective alkali, and at a lower H factor, by keeping the dissolved organic material (DOM) concentration low substantially through the entire kraft cook, incl...	08/28/2001
6280575	Frusto-conical outlet for a cellulose material treatment vessel In a cellulose pulp handling vessel having a first diameter material storing or treating portion above a second diameter discharge which is at least 20% less than the first diameter, reduced compression of the material and reduced power requirements of an...	08/28/2001
6277240	Method for continuously pulping cellulosic fibrous material In the production of chemical pulp, such as kraft pulp, it is possible to reduce the amount of ancillary equipment, and/or the size of the continuous digester vessel, while achieving enhanced uniformity of treatment by avoiding "hang ups". Instead of prov...	08/21/2001
6261412	Regenerative heat recovery for high temperature condensate stripping plants The EPA Cluster Rules for cellulose pulp mills are complied with by first collecting foul condensate including hazardous air pollutants (HAPs), such as methanol, at a temperature of between about 140-180° F., and passing the foul condensate into direct c...	07/17/2001
6248208	Pretreatment of chips before cooking The strength properties of chemical cellulose pulp (particularly kraft pulp) are improved by substituting a cold impregnation soak for conventional impregnation procedures. After steaming, wood chips are soaked in an alkaline liquid at a temperature of ab...	06/19/2001
6241851	Treatment of cellulose material with additives while producing cellulose pulp Chemical cellulose pulp (e.g. kraft pulp) is produced with enhanced strength and/or yield using a strength or yield enhancing additive such as polysulfide or anthraquinone or its equivalents or derivatives, and in a manner that allows effective recovery/r...	06/05/2001
6199299	Feeding of comminuted fibrous material to a pulping process In a chisel-type convergence for a chip bin in a wood chip pulping process and system, an improvement in uniformity of discharge of the chips from a chips bin or the like is provided. The bin includes a conventional hollow substantially right circular cyl...	03/13/2001
6186373	Hopper, or bin, screw feeder construction controlling discharge velocity profile A bin or hopper, preferably with one-dimensional convergence, has a slot outlet at its bottom for discharging bulk solid particulate material (such as coal, wood chips, sugar, plastic pellets, etc.) to a screw in a trough. The screw has varying flight dia...	02/13/2001
6176971	Heat economy enhancements for the recovery and use of energy obtained from spent cooking liquors Useable steam, e.g. substantially clean useable steam, is produced from a chemical cellulose pulping system hot spent treatment liquor (e.g. black liquor) with optimum energy efficiency by passing the spent liquor to a reboiler, and then pressurizing (e.g...	01/23/2001
6174411	Continuous digester with inverted top separator A cellulose pulp continuous digester (e.g. for producing kraft pulp) is operated so that it has an inverted top separator and is hydraulically filled to above the level of the inverted top separator, and may be substantially completely hydraulically full....	01/16/2001
6165323	Screen plate having a plurality of inclined slots in a digester A screen assembly particularly adapted to be used in a continuous or batch digester in the production of cellulose (chemical) pulp utilizes a particular screen plate construction that enhances productivity while minimizing blockage of the screen slots (an...	12/26/2000
6159337	Dissolved organic materials control in cellulose pulp production Kraft pulp of increased strength and bleachability may be produced with decreased consumption of effective alkali, and at a lower H factor, by keeping the dissolved organic material (DOM) concentration low substantially through the entire kraft cook, incl...	12/12/2000
6143134	Chip spreader for air-lock feeder By establishing a relatively flat, for example, non-sharply conical, top profile of wood chips in a treatment vessel (such as a chip bin), the chips will be more uniformly steamed or otherwise treated (or have the treatment time of the chips extended) com...	11/07/2000
6132556	Method of controlling pulp digester pressure via liquor extraction A method of controlling the pressure of a vertical continuous comminuted cellulosic fibrous material (wood chip) digester is provided using a pressure-control extraction in a zone relatively insensitive to changes in the flow rate of liquid introduction o...	10/17/2000
6129816	Tapered screen assembly for a cellulose pulp digester A comminuted cellulosic fibrous material treatment vessel assembly includes a substantially vertical vessel having a top, bottom, and outlet, and through which the material flows in a flow direction. The vessel preferably has a substantially cylindrical w...	10/10/2000

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Assignee: Andritz-Ahlstrom Inc.