The vertical pulp digester is the core equipment in the batch cooking of paper pulp. This type of pulp digester has many advantages, including large digester volume, large production capacity, high productivity, and small floor area compared with the steam ball of the same volume. But it also has some shortcomings, such as more accessory equipment, complex structure, high manufacturing requirements, and high investment costs.
Paper Pulp Digesters from Anyang Machinery
Paper pulp digester series are our leading products. We can manufacture various specifications of pulp digesters, including 50m3, 75m3, 110m3, 135m3, 175m3, 225m3, 250m3, and 400m3 pulp digesters used in paper mills. The maximum size of the pulp digester is 5.8m in diameter and 400m3 in volume. According to different production technologies of alkaline pulping and acid pulping, digester series can be made of different raw materials, for example, carbon steel structure, composite steel structure, or dual-phase stainless steel. The pulp digester series is mainly used in the chemical pulp and dissolved fiber steaming section. Our pulp digesters can compare favorably with similar productions made by GLV or other famous international companies of chemical pulp production line equipment, so they are widely used in China.
Pulp Digester Design Structure
Kraft pulp cooking digesters are thin-walled pressure vessels welded by steel plates. It is mainly composed of digester body, cover, loading device, spray valve, chemicals heating circulation device, and support.
The digester body can be divided into three parts: the upper part, the middle part, and the lower part. The upper part and the lower part are usually formed to cone shape or ball shape, the digester body is usually formed to a cylinder shape.
The height and diameter of the pulp digester and the size of the upper and lower cone angles are important indicators of its shape. If the ratio of height to diameter is too large, the cooking digester will be too high, which will increase the investment in plant construction. If the ratio is too small, it is easy to cause uneven distribution of circulating chemicals in the cross-section of the whole digester, which will lead to the uneven temperature rise of materials, and eventually lead to unstable pulp quality and poor pulp yield. Generally, the ratio of height to diameter of Kraft pulp digester is between 3.3 and 4.
The upper cone angle of a pulp digester is generally about 90 ° and the lower cone angle is about 60 °. The size of the upper and lower cone angle has a certain impact on the operation of the digester such as feeding, discharging, and ventilation. If the upper cone angle is too large, it is difficult to compact the materials on the top of the digester and reduce the loading capacity; if the lower cone angle is too large, it is easy to cause incomplete discharging and uneven heating during direct ventilation.
Main clients of our paper pulping digester production
- Chongqing Papermaking Company: Annual 200,000 tons of chemical pulp production line
- Chongqing Lee & Man Papermaking Company: Annual 100,000 tons of dissolving pulp production line
- Fujian Qingshan Papermaking Company: Annual 100,000 tons of dissolving pulp production line
- Hunan Juntai Papermaking Company: Annual 300,000 tons of dissolving pulp production line
- Huatai Papermaking Company: Annual 200,000 tons of wood pulp production line and annual 100,000 tons of dissolving pulp production line