At present, the fiber materials for paper making mainly include wood pulp and straw pulp, wood pulp takes 90% of the whole system, and straw pulp takes the rest 10%. Recently, waste paper pulp capacity increase with the development of waste paper making.
Wood pulp plant is generally in the forested countries and regions, such as northern Europe, North America, and Russia. In recent years, South America and Southeast Asia greatly develop fast growing forest plantation, which provides fiber materials for wood pulp making.
The straw pulp is mostly produced from China, including bagasse pulp, bamboo making, reed pulp, wheat straw pulp, and rice straw pulp, etc. Due to short fiber, most of the straw pulp papers have bad strength compared to wood pulp paper. For example, virgin sugar bagasse pulp can be only used to produce low-grade writing paper and tissue paper. After mixing with long-fiber pulp like softwood pulp or bamboo pulp, bagasse pulp can be applied to printing paper and sanitary paper manufacture. Bamboo is a super fibers materials for paper and pulp making.
Bamboo is one part of gramineae, so bamboo pulp belongs to straw pulp. The stalk of bamboo is strong as wood, so bamboo pulp making is similar to wood pulp making. As for the fiber length, the bamboo pulp is between softwood pulps (long fiber) to hardwood pulp (short fiber), so the bamboo pulp is better than hardwood pulp and worse than softwood pulp.
Comparison of bamboo pulp, wood pulp and bagasse pulp
The pulp property usually refers to the fiber length and length-width ratio of fiber. Like we mentioned above, long fiber is good for high-grade paper making. In general, most of the straw fiber are an annual plant, the fiber length and thickness of cell wall is worse than perennial woody plants. Bamboo is a perennial plant, growing period is about three years. For paper and pulp making, the applicability of materials is depended on the cellulose content and fiber length. We compare the fiber property and composition of various kinds of materials including bamboo, hardwood, softwood and sugarcane bagasse, specifications as follow:
Table1：Composition of fiber materials
| Yellow bamboo | Green bamboo | Masson pine | Eucalyptus | Sugar bagasse | |
| Hemicellulose (%) | 17.97 | 18.70 | 10.83 | 10.27 | 23.51 |
| Lignin (%) | 22.88 | 21.94 | 29.01 | 27.45 | 19.30 |
| Cellulose (%) | 44.96 | 49.21 | 45.51 | 44.25 | 42.16 |
Table2: the property of fibers
| Yellow bamboo | Green bamboo | Masson pine | Eucalyptus | Sugarcane bagasse | |
| Average length | 1.55 | 1.49 | 3.6 | 0.88 | 0.8 |
| Ratio of width and length | 113 | 102 | 72 | 56 | |
| Rating | preferably | preferably | good | general | bad |
Note: the length of sugarcane bagasse fiber is 0.8mm, but the average length of sugarcane fiber is 1.7mm.
From the table1 and table2, we can find the following results:
- Excepting for the sugarcane bagasse, Masson pine, eucalyptus and bamboo all have a high content of cellulose, they will have high pulp yield and reduce the cost.
- Bamboo fiber also has a longer length, long fiber will have good felt properties, so bamboo pulp paper always has high strength.
Table3: the cost of different fiber materials pulp making
| unit | Bamboo pulp | Softwood Pulp | Hardwood pulp | |
| Material (40% water) | t or m3 | 3.7t | 5.2m3 | 4.2t |
| Alkaline consumption(NaOH) | t/t | 0.45 | 0.55 | 0.32 |
| Water consumption | t/t | 150 | 100 | 150 |
| Power consumption | kilowatt | 400 | 450 | 350 |
| Steam consumption | t/t | 4.5 | 5.0 | 3.8 |
| Bleaching agent | cheap | expensive | cheap | |
| Pulp mill size | 30-80 kt | 300-500 kt | 30-50 kt | |
| Pulp mill equipment | Pulp digester, blow tank, vacuum drum washer, etc. | Pulp digester, blow tank, vacuum drum washer, etc. | Pulp digester, blow tank, vacuum drum washer, etc. | |
| Bleaching | 4 or 5 stage bleaching | 5 stage bleaching | 3 or 4 stage bleaching | |
| investment | small | large | small | |
| Investment per unit | ten thousand yuan | 0.5-0.6 | 1.25-1.50 | 0.45-0.6 |
| Pulp cost | Yuan/t | 2750.5 | 3950 | 2260 |
Bamboo pulp production line needs lower cost compared to softwood pulp, and bamboo price is low. Bamboo pulp belongs to long fibers, so it is better than sugarcane bagasse pulp, apply for high-grade paper making. In a word, bamboo pulp has a brighter future.
Advantages of bamboo pulp making
- Bamboo pulp making is beneficial to the ecological environmental protection. Pulp mill always develops the raw material base, bamboo forest increase the forest coverage rate.
- The planting and felling of bamboo are different to the wood fibers, three-year forest establishment period and intermediate cuttings will reduce ecological influence.
- Bamboo planting also improves the economy, pulp mill also bring related employment opportunities.
