Abstract: A drainer for a feed system for a cellulose digester has a substantially open and hollow inlet (devoid of a spiral flow imparter or a like flow restriction) and a substantially annular screen within an elongated housing having a flow direction between the housing inlet and outlet. The screen is slotted and the slots are at an angle &agr; between 5-90° with respect to the flow direction, so as to minimize passage of cellulose material through the slots, or clogging of the slots.

Abstract: A feed system for a cellulose pulp treating vessel (such as a continuous digester) is not limited by the required L/W ratio of the pump feeding a wood chip slurry to a high pressure transfer device, the feed system may be kept at a low temperature to minimize flashing of liquid into steam, and a return conduit from the treatment vessel to the transfer device high pressure inlet may be eliminated. Some of the liquid is removed from the slurry just before the low pressure inlet to the transfer device, and/or just after the high pressure outlet, to reduce the L/W ratio of the slurry by at least 0.25, e.g. from 3.0:1 to 2.25:1 just before the low pressure inlet, and from, 7.0:1 to 5.0:1 substantially immediately after the high pressure outlet.

Abstract: A feed system for a cellulose pulp treating vessel (such as a continuous digester) is not limited by the required L/W ratio of the pump feeding a wood chip slurry to a high pressure transfer device, the feed system may be kept at a low temperature to minimize flashing of liquid into steam, and a return conduit from the treatment vessel to the transfer device high pressure inlet may be eliminated. Some of the liquid is removed from the slurry just before the low pressure inlet to the transfer device, and/or just after the high pressure outlet, to reduce the L/W ratio of the slurry by at least 0.25, e.g. from 3.0:1 to 2.25:1 just before the low pressure inlet, and from 7.0:1 to 5.0:1 substantially immediately after the high pressure outlet.

Abstract: A feed system for a cellulose pulp treating vessel (such as a continuous digester) is not limited by the required L/W ratio of the pump feeding a wood chip slurry to a high pressure transfer device, the feed system may be kept at a low temperature to minimize flashing of liquid into steam, and a return conduit from the treatment vessel to the transfer device high pressure inlet may be eliminated. Some of the liquid is removed from the slurry just before the low pressure inlet to the transfer device, and/or just after the high pressure outlet, to reduce the L/W ratio of the slurry by at least 0.25, e.g. from 3.0:1 to 2.25:1 just before the low pressure inlet, and from 7.0:1 to 5.0:1 substantially immediately after the high pressure outlet.

Abstract: In a pulp treatment vessel, such as a kraft pulp continuous vertical digester, a cellulose slurry is caused to flow in the vessel interior in a flow path. A substantially annular void is formed at at least one point along the flow path, and dilution or treatment liquor is introduced into the substantially annular void so that the liquor is substantially uniformly distributed about the periphery of or into the slurry. The annular void may be formed by a step out in the vessel, and the uniform introduction of dilution liquor may be accomplished utilizing one or more openings, such as a plurality of openings substantially evenly spaced around the substantially annular void, e.g. using a screen surface. The screen surface may be substantially vertical or conical.

Abstract: A chip bin construction, ideally suited for bins having a maximum diameter of twelve feet or more, uniformly discharges chips, after steaming, without the necessity of a vibratory discharge. A hollow transition portion is provided between a hollow substantially right circular cylindrical main body and a rectangular discharge. The hollow transition may have a substantially circular cross-section open top and a substantially rectangular cross-section open bottom and opposite non-vertical gradually tapering side walls. At least one feed screw may be mounted at the open bottom of the transition for cooperation with the discharge, and the feed screw(s)--or the equivalent--may provide for metering of the chips. Alternatively, the hollow transition portion may provide one dimensional convergence and side relief, and no screw feeders need be provided, in which case a conventional chip meter is used.

Abstract: Located within the annular screen of the pressure diffuser is a tubular baffle hung from adjacent the top of the vessel. The baffle has two headers disposed on its inner surface, with openings in the tube providing communication between the exterior of the tube and the headers. A conduit extends from each header to an arm at the top of the vessel, to allow extracted liquid to be discharged. Another extraction conduit is provided at the bottom of the vessel, in communication with the screen interior and the tubular baffle interior. Treatment liquid, such as wash liquid, may be introduced at two, three, or more positions along the vessel with the liquid extracted from the first and second headers being introduceable at different positions along the vessel. A flexible, elastomeric material, sealing element with integral annular skirt may extend from the bottom end of the tubular baffle and engage the screen to provide a seal minimizing mixing between stages.

Abstract: Biomass, such as bagasse, is pre-hydrolyzed, to ultimately effect hydrolysis of hemicellulose to sugars. Biomass is mixed with a mineral acid solution to form a slurry having a consistency of about 8 to 12% so that the acid solution properly wets the biomass. Then the slurry is dewatered to about 35 to 50% consistency, and is heated to reaction temperature (e. g. about 320.degree. F.) by direct contact with steam in the vapor phase of a vertical pressurized reactor, having a pressure of about 40 psig. A fluffer is preferably provided in the top of the reaction vessel. After a reaction time of about 30 minutes, the biomass is diluted and cold blown out of the bottom of the reactor. Pressate from the dewatering has acid added to it and is heated by indirect heat exchange with a sugar solution obtained by washing of the biomass discharged from the reactor, and is then mixed with the biomass as the acid solution.

Abstract: In the production of cellulose pulp (e.g. kraft pulp) utilizing a continuous digester having a number of different feed points for cooking (e.g. white) liquor and utilizing a high pressure feeder, the volume of cool white liquor that is applied to the feed system is reduced compared to conventional processing. This can cause excessive hammering, and damage the high pressure feeder and adjacent piping and equipment. In order to avoid this, liquid being recirculated from the top of the digester back to the high pressure feeder is cooled by passing it into a heat exchanger into heat exchange relationship with a cooler liquid, with the flow of coolant automatically controlled by sensing the temperature of the recirculated liquid. The temperature in the feed system can further be lowered by cooling the cooking liquor before it is added to the pulp slurry, as by passing it to a flash tank so that its temperature is reduced at least 10.degree. C., and the flashed steam can be used in an evaporator.

Abstract: The proper pressure conditions are maintained within an atmospheric pre-steaming chips bin used in the production of paper pulp. Extending upwardly from the top of the chips bin is a vertical section of conduit, an elbow section, and a horizontal section. A door guide with a door opening in it is disposed in the horizontal section and precludes passage of gas through the horizontal section except through the door opening. A pivot pin mounts a door at its top so that it normally assumes a vertical orientation closing off the opening, and it is adjustably biased into that orientation by a counterweight mechanism. The counterweight includes weight discs which mount on a vertical section of rod having external screw threads, and a horizontal section of rod is connected by a flange to a flange of the pivot pin.

Abstract: An assembly and method provide for the simultaneous heating of process inlet water from a clean water source, and condensing of a condensable gas using the process inlet water and a closed loop of condensing water. A plurality of pairs of condenser plates are disposed in an annular array in a vertical cylindrical vessel. First and second liquid inlets are disposed at the top of the vessel separated by a radially extending fixed baffle, and first and second liquid outlets are disposed at the bottom of the vessel separated by a radially extending fixed baffle. A condensable gas passes through the interiors of the pairs of condensing plates. Movable top and bottom baffles are rotatable through arcs to change the number of condensing plates operatively communicating the first liquid inlet with respect to the second liquid inlet, the liquid flowing between the first liquid inlet and outlet being always segregated from the liquid flowing between the second liquid inlet and outlet.

Abstract: An assembly and method provide for the simultaneous heating of process inlet water from a clean water source, and condensing of a condensable gas using the process inlet water and a closed loop of condensing water. A plurality of pairs of condenser plates are disposed in an annular array in a vertical cylindrical vessel. First and second liquid inlets are disposed at the top of the vessel separated by a radially extending fixed baffle, and first and second liquid outlets are disposed at the bottom of the vessel separated by a radially extending fixed baffle. A condensable gas passes through the interiors of the pairs of condensing plates. Movable top and bottom baffles are rotatable through arcs to change the number of condensing plates operatively communicating the first liquid inlet with respect to the second liquid inlet, the liquid flowing between the first liquid inlet and outlet being always segregated from the liquid flowing between the second liquid inlet and outlet.

Abstract: An improved lifting mechanism for an apparatus for continuously feeding solid particles into a pressure vessel of the type disclosed in U.S. Pat. No. 4,125,384, the lifting mechanism comprising an elongated cylindrical housing assembly operatively disposed with its axis extending at an angle to the horizontal and to the vertical. The housing assembly includes end structures closing the upper and lower ends thereof, a water and particle inlet for pressure communication with the pressure vessel of the apparatus leading downwardly into the interior of the housing assembly adjacent the closed lower end thereof and a particle outlet for pressure communication with the container of the apparatus leading downwardly from the interior of the housing assembly adjacent the closed upper end thereof.