The digester is actually a steamer. Vertical digester A type of retort with a large vertical intermittent production of pulp. The top and bottom are semi-spherical or conical, and the middle is cylindrical. It has a large amount of pulp, a small footprint, and a uniform pulp quality. Advantages; suitable for the production of wood pulp, mash, straw pulp, etc. by the sulfate method and the sulfite method.
Features of the rotary vertical digester in the digester equipment:
The volume, transmission mode and cooking operation mode of the rotary vertical digester are similar to those of the steaming ball. This rotary vertical digester used to be used for the cooking of sulphate wood pulp in Europe, with a small volume of only 20 to 50 m. The diameter is generally 2.5~3m, the height is 6~7.5m, the ratio of height to diameter is 2.0~2.5, and the upper and lower cone angles are all 90 degrees. There will also be a steam pipe D in the digester, which is extended to the upper port and connected to an O-shaped pipe at the end for steam charging and steaming. There will also be a valve E on the lower part of the digester for venting air and turpentine, which is 25~30% of the digester volume.
Characteristics of the kraft digester in the digester equipment:
At present, the kraft digester is mainly used in large and medium-sized pulp and paper mills, and the main raw materials for cooking are wood, reed, and bamboo. The digester is a thin-walled pressure vessel welded with 209 boiler steel plates. And the kraft digester is composed of a pot body, a circulation system and a support base. When the device is in use, the temperature is higher and the lower pressure is higher, and the mixing can make the cooking uniform. However, it should be noted that when the liquid suction filter is installed in the lower part of the pot and the slurry having poor water filtration is distilled, the circulation amount of the liquid medicine in the late cooking stage is reduced.
Fixed vertical digester in digester equipment:
Fixed vertical digester, according to the different heating methods, this time will be directly divided into direct heating and indirect heating forced circulation. These two kinds of digester are produced in our country. For example, the Jiamusi paper mill digester belongs to the indirect heating forced circulation and is supplemented by direct heating. The Jilin pulverizer is a direct heating forced circulation mode.
The fixed vertical digester in the digester equipment is relatively large in volume, and the production capacity itself is relatively large, which is adopted for large and medium-sized factories. In terms of this volume, it is generally 50~170m3. At present, the largest vertical digester in the world is 260m3. When actually using it, it is also necessary to pay attention to a vertical digester without a heater, and the steam is directly introduced into the digester to increase the amount of condensed water in the device, and in this respect, Care should be taken to consider that the cooking liquor ratio should be properly reduced.
