Nippon Paper Industries Co., Ltd.

Other

Permelec Electrode Ltd.

Hitachi-johnson Controls Air Conditioning, Inc.

Kawasaki Kasei Chemicals Ltd.

Asahi Glass Company, Limited

Keigo Watanabe

Shisei Goto

Hiromichi Tsuji

Yasunori Nanri

Takeshi Iimori

Tatsuya Andoh

Takanori Miyanishi

Junji Tanaka

Makoto Nakao

Isao Onodera

Tetsuji Shimohira

Takamichi Kishi

Kazuhiro Kurosu

Kazuaki Sakai

Yasuyuki Kamijo

Isamu Tsubono

Yohji Tuji

Kenji Takesawa

Naohiro Tsuchiya

Yasuhiro Kishi

Hirokatsu Kosokabe

A rolling cylinder displacement compressor including a minimum pressure bypass port as an opening of a minimum pressure bypass valve flow path, which is connected to a compression chamber formed in the compression portion in a lowest pressure state, of the bypass valve flow path is arranged such that a compression chamber faces an opening of the discharge flow path or the minimum pressure bypass port. The minimum pressure bypass port may be configured such that a minimum pressure port center as the center of the minimum pressure bypass port is arranged in a rotation advanced-side region with respect to an advanced radius line as a line connecting a cylinder advanced corner point of the compression chamber at the start of a compression stroke and the rotation center of the rolling cylinder.

Rolling cylinder displacement compressor

A continuous cooking process making use of a digester, which includes therein, from a top toward a bottom of the digester, a top zone, an upper cooking zone, a lower cooking zone and a cooking/washing zone and also includes strainers provided at the bottom of the respective zones and wherein a cooking black liquor extracted from at least one of the strainers is discharged to outside a digestion system, a process for cooking a lignocellulose characterized by feeding, upstream of the top of the digester, a first cooking liquor containing an alkaline cooking liquor having a specified composition, feeding a second cooking liquor of an alkaline cooking liquor made mainly of sodium hydroxide to the upper cooking zone, and feeding a third cooking liquor of an alkaline cooking liquor similar to the second cooking liquor to the cooking/washing zone.

Cooking process of lignocellulose material

The first invention aims to provide a method for preparing stiffer bulky pulp at a freeness level comparable to that obtained by mechanical treatments to improve the bulkiness of product paper by searching for a method capable of adjusting freeness while suppressing damage to pulp fibers and internal fibrillation in a process for producing pulp. The second invention aims to strip contaminants deposited on pulp fibers and/or inorganic particles to reduce adhesion of the contaminants and decrease microorganisms in a treatment of process water containing long pulp fiber fractions used in a process for producing pulp and paper, thereby clarifying process water and thus preparing high-quality pulp and paper. According to the first invention, cavitation is generated in a pulp suspension preferably by a liquid jet and the resulting fine bubbles are introduced into the pulp suspension to adjust the pulp suspension to a desired freeness by means of the impact force induced by collapse of the fine bubbles in a process for producing pulp. According to the second invention, process water containing 50% by weight or less, based on total solids, of long pulp fiber fractions used in a process for producing pulp and/or paper is treated by cavitation generated by a liquid jet and then returned to the process for producing pulp and/or paper and reused.

Methods for beating pulp, methods for treating process waters, and methods for producing pulp and paper

A papermaking raw material processor capable of reforming pulp in papermaking a process using cavitation includes a first pumpjets jet liquid and second pumpjets suspension containing; e.g., pulp fibers into a processing unit inside which cavitation is generated by generation of a jet stream. Inside processing unit, a jet stream generates cavitation to carry out a reforming processing in which ink, or the like, is removed from the fibers by a blast resulting from collapse of cavitation bubbles generated there. The liquid after reforming processing is returned to second tank, except for a part of it fed to downstream steps, while the suspension is processed, as circulated between processing unitand second tank

Apparatus for treating papermaking feedstock

Pulp processing equipment used to produce high-quality recycled pulp with little damage to fibers, high brightness and low residual ink by means of a force selectively acting on fiber surfaces during the process of recycling waste paper is disclosed. Moreover, fiber surfaces are modified by means of a force acting on only the fiber surfaces to obtain high-quality pulp and to render harmless dirts deteriorating pulp quality. A jet system is provided having one or more nozzles for jetting an aqueous slurry containing a material comprising cellulose into a vessel.

Methods for producing recycled pulp, methods for modifying pulp fiber surfaces and dirts, as well as pulp processing equipments

The present invention aims to produce high-quality recycled pulp with little damage to fibers, high brightness and low residual ink by means of a force selectively acting on fiber surfaces during the process of recycling waste paper. Moreover, fiber surfaces are modified by means of a force acting on only the fiber surfaces to obtain high-quality pulp and to render harmless dirts deteriorating pulp quality. A method for producing recycled pulp characterized in that cavitation is generated and used to strip contaminants deposited on fibers and ash during the process of recycling waste paper. Contaminants such as ink deposited on fibers and ash are stripped/fragmented by means of the impact force induced by collapse of fine bubbles by actively introducing bubbles generated by cavitation into a pulp suspension. A jet system having one or more nozzles for jetting an aqueous slurry containing a material comprising cellulose into a vessel.

Methods for producing recycled pulp and methods for modifying pulp fiber surfaces using liquid jet cavitation

Wood chips having low bleachability are impregnated with a chemical liquor at a pH range of 7-12 in aqueous solution and the chemical liquor from the impregnated chips is drained, whereby extractives contained in the chips and consuming bleaching agents can be removed to improve the effect of bleaching agents in a subsequent bleaching step. Bleached mechanical pulp is prepared by defibration by primary refining&#x2014;bleaching&#x2014;beating by secondary refining wherein pulp fibers are washed after defibrating wood chips having low bleachability and before bleaching the pulp fibers, whereby the amount of bleaching agents used can be reduced and bleached mechanical pulp having a Hunter brightness of 45-65% after secondary refining can be obtained.

Process for impregnating, refining, and bleaching wood chips having low bleachability to prepare mechanical pulps having high brightness

A lignocellulose material is cooked by means of an alkaline cooking liquor containing polysulfides in the presence of a quinone-hydroquinone compound, of which the oxidation-reduction potential in the form present during the cooking, which potential is a value calculated as a standard oxidation-reduction potential (Ea) with a hydrogen ion activity of 1, is within a range of from 0.12 to 0.25V to the standard hydrogen electrode potential. It is thereby possible to cook the lignocellulose material with a low Kappa number and in good yield and at the same time, to reduce the amount of the chemical solution used and to reduce the load on a recovery boiler.

Cooking method for pulp

In a process for producing kraft pulp, the process is made closed, the yield of pulp is improved and environmental problems are minimized. An alkaline solution containing Na S which flows in a process of producing kraft pulp, is electrolyzed by an electrolytic oxidation method; a liquid which is formed at an anode side and contains a polysulfide type sulfur in an amount of 6 g/l or more, is added, as it is or after being causticized, to the process before a chip has the maximum temperature, and a NaOH solution formed at a cathode side, is added to at least one step of the process after the chip has the maximum temperature till a final bleaching stage; and at least chemicals in the step wherein NaOH is added, among chemicals discharged in all steps from a cooking step till the final bleaching stage, are recovered and reused.

Method for recovering chemicals in a process of producing pulp by kraft process

The present invention has an object to obtain a cooking liquor containing polysulfide-sulfur at a high concentration by minimizing by-production of thiosulfate ions. The present invention is a method for producing polysulfides, which comprises introducing a solution containing sulfide ions into an anode compartment of an electrolytic cell comprising the anode compartment provided with a porous anode, a cathode compartment provided with a cathode, and a diaphragm partitioning the anode compartment and the cathode compartment, for electrolytic oxidation to obtain polysulfide ions, characterized in that the porous anode is disposed so that a space is provided at least partly between the porous anode and the diaphragm, and the apparent volume of the porous anode is from 60% to 99% based on the volume of the anode compartment.

Growing community of inventors

Tokyo, Japan

Keigo Watanabe