摘要:
Provided is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, provided are a method for preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution in a bucket conveyor type contactor to generate a contact mixture, and draining the contact mixture; a method for preparing a cellulose ether comprising use of the alkali cellulose thus prepared; and an apparatus for preparing alkali cellulose comprising a bucket conveyor contactor comprising at least one inlet port for introducing pulp and an alkali metal hydroxide solution at one end and at least one outlet port for discharging a contact mixture wherein the pulp and the alkali metal hydroxide solution can be moved from one end to the other end while bringing them into contact with each other to generate the contact mixture; and a drainer for separating a cake from the contact mixture discharged from the outlet port.
摘要:
Es wird ein Verfahren (200, 201, 202) zur Rückgewinnung von alkalischer Lösung (1) aus mit Hemicellulosen (22) verunreinigter wässriger alkalischer Lösung (2), sowie eine Vorrichtung (100, 101) zur Durchführung des Verfahrens (200, 201, 202) gezeigt, bei dem die wässrige alkalische Lösung (2) als Feedstrom (14) und Prozesswasser (10) als Gegenstrom (15) über eine lonentauscher-Diffusionsdialyse (3, 31) mit zumindest einer Dialysemembran (4, 41, 42, 43, 44, 45) zwischen Feedstrom (14) und Gegenstrom (15) geführt werden und dabei in ein alkalisch angereichertes Diffusat (13) als rückgewonnene alkalische Lösung (1) und ein mit Hemicellulosen (22) angereichertes Dialysat (9) umgesetzt werden. Um den Wartungsaufwand des Verfahrens der eingangs erwähnten Art zu reduzieren und dessen Standzeit zu erhöhen, wird vorgeschlagen, dass vor dem Zuführen zur lonentauscher-Diffusionsdialyse (3, 31) Gaskomponenten (28) aus dem Prozesswasser (10) des Gegenstroms (15) entfernt werden.
摘要:
The objective of the present invention is to provide a method for easily and efficiently producing cellulose beads which have pore shape suitable for an adsorbent and of which adsorption performance is excellent without using highly toxic and highly corrosive auxiliary raw material and without industrially disadvantageous cumbersome step. The method for producing porous cellulose beads according to the present invention is characterized in comprising (a) the step of preparing a fine cellulose dispersion by mixing a low temperature alkaline aqueous solution and cellulose, (b) the step of preparing a mixed liquid by adding a crosslinking agent to the fine cellulose dispersion, (c) the step of preparing an emulsion by dispersing the mixed liquid in a dispersion medium, (d) the step of contacting the emulsion with a coagulating solvent.
摘要:
The present invention relates to a process for the production of alkali cellulose for the production of alkali cellulose and, optionally, cellulose ethers from cellulose in the presence of alkali and, if applicable, with alkylating and/or hydroxyalkylating agent(s) comprising the reaction of a cellulose with an alkali metal hydroxide, wherein the alkali metal hydroxide is mixed with cellulose in a mixing apparatus, the mixing apparatus (1) having an upper region (20, 102a, 202a) with a first cross-section and a lower region (21, 102b, 202b) with a second cross-section, the second cross-section being the same as or smaller than the first cross-section and comprising at least one non-horizontally oriented mixing device (23, 27, 121, 221, 224).
摘要:
Provided is an efficient method for preparing alkali cellulose having the low water content and a uniform alkali distribution therein. More specifically, provided is a method for continuously preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution to generate a contact mixture and then draining the contact mixture by a centrifugal separator. Also provided is a method for preparing cellulose ether comprising a step of etherifying the alkali cellulose.