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:
Provided is a method for efficiently preparing alkali cellulose having a uniform alkali distribution. More specifically, provided are a method for preparing alkali cellulose comprising a contact filtration step of bringing a pulp into contact with an alkali metal hydroxide solution on a moving filtration plane for vacuum filtration to collect a contact product remaining on the filtration plane, and a draining step of draining the contact product; and a method of preparing cellulose ether by using the alkali cellulose. Also provided is an apparatus for preparing alkali cellulose comprising a continuous horizontal vacuum filter type contactor comprising a horizontal filtration plane moving in a horizontal direction, a pulp inlet for introducing pulp onto the moving filtration plane, a spray port for spraying an alkali metal hydroxide solution to the introduced pulp, a vacuum pump enabling vacuum suction of the moving filtration plane, and an outlet for collecting a contact product remaining on the filtration plane after bringing the pulp into contact with the alkali metal hydroxide solution on the moving filtration plane for vacuum filtration.
摘要:
Provided is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, pulp and an excess alkali metal hydroxide solution are introduced continuously in a screw conveyor type contactor and brought into contact with each other in the screw conveyor type reactor. By changing at least one factor selected from the group consisting of a rotation speed of the screw conveyor, a screw pitch and a length of immersion zone, a ratio of an alkali to cellulose in the alkali cellulose obtained by draining is controlled. The alkali cellulose thus obtained is etherified into the corresponding cellulose ether.
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.