The sugarcane bagasse is a by-product of the sugar industry and a fine material of paper pulp production. It is a kind of fibrous waste containing lignin and cellulose after the juice of sugarcane is squeezed out by the press.
The color of the bagasse is grayish yellow to light green. It is a mixture of hard fiber and soft parenchyma (bagasse pith). The bagasse contains rich cellulose. The main chemical components are about 50% cellulose (C6H10O5)n, about 25% hemicelluloses (C5H804)n, and about 25% lignin.
Bagasse pulp paper has good evenness, smoothness, and strong ink absorption ability, so it has a broad application prospect. The bleached bagasse pulp mixed with a certain amount of long fibers can be used to produce high-grade printing paper, writing paper, paper tissue, coated paper, etc.
Bagasse Pulp Advantages
As a type of paper making material, the bagasse has its own features compared with wood and straw materials:
1. The source of bagasse supply is stable. Large-scale sugar industry can produce a large number of bagasse, and the bagasse is convenient to store and transport.
2. The content of cellulose in bagasse is generally 50% ~ 55%, which is higher than straw and equivalent to wood; the lignin content is about 20%, higher than straw and lower than wood, so bagasse pulp is easy to cook; silicon content is lower than straw and higher than wood, so alkali recovery of bagasse pulping black liquor is easier than that of straw pulp.
3. Bagasse is a kind of mixed fiber material with heterogeneous structure and different size particles. The pith ratio of bagasse is about 35%~40%, which is the reason why bagasse has strong absorption ability. However, the bagasse pith has no interlacing force, so it should be removed from the bagasse before the pulping process.
Bagasse Pulp Making Process
The making process of bagasse pulp can be divided into four steps: pulp cooking, pulp washing, screening, and pulp bleaching.
Bagasse Pulp Cooking Equipment
The bagasse pulp cooking process uses the continuous alkaline cooking and cold spray pulping methods. The equipment used in this process is the horizontal tube continuous cooking digester. Compared with the traditional batch digester, it has the following advantages:
1) The pulp cooking is quicker, and consumes less alkaline and steam;
2) The yield of pulp is 5% higher than that of other pulp cooking procedures at the same K value, and the pulp has more uniform quality and higher strength;
3) It is conductive to heat recovery, and the steam peak load problem encountered in batch digester cooking will not occur.
4) Its designed structure is compact and easy to operate and manage;
5) Continuous cooking has low failure rate and low labor cost, which is suitable for large-scale modern pulp production.
Bagasse Pulp Washing Equipment
The most used pulp washing equipment in the bagasse pulp making process is the vacuum drum washer, which has many advantages such as low production cost, easy operation, and high extraction rate of black liquor and so on.
Bagasse Pulp Screening Equipment
Traditional bagasse pulping plants often use open low consistency screening systems to screen pulp. The screening concentration of this system is 0.8 ~ 1.0%. This system uses CX screen and low concentration desander, it consumes as high as 100m3 water to screen each ton of pulp, and discharges 75m3 wastewater.
Modern bagasse pulping plants mostly use the close medium consistency screening system. Compared with the traditional system, this system improves the screened pulp quality and consumes less water, and produces less wastewater during the pulp screening process.
Bagasse Pulp Bleaching Equipment
The basic configuration of the pulp bleaching section is: washing and concentration equipment, pulp conveying equipment, pulp mixing equipment, bleaching agent and auxiliary agent, bleaching reaction tower, etc.
The bagasse pulp is relatively easy to bleach; the CEH three-phase bleaching system is able to bleach the bagasse pulp to 80%ISO. The equipment in this system includes pulp pump, mixer, chlorination tower, alkaline treatment tower, hypo tower, and pulp thickening machine.
Conclusion
Bagasse is a kind of papermaking resource with high quality and strong regeneration. Making full use of bagasse for papermaking can alleviate the current global wood shortage and help worldwide environmental protection.
CNBM affiliate Anyang Machinery has been focused on the development and manufacturing of paper pulping machines for five decades. We have rich experience in the design and construction of bagasse pulp mill plant. Please feel free to drop us an e-mail to tell us your needs in the paper pulp industry!