Method for preparing bamboo pulp with full liquid phase pre-hydrolytic sulfate rapid displacement cooking

Abstract

The invention discloses a method for preparing bamboo pulp with full liquid phase pre-hydrolytic sulfate rapid displacement cooking. The method comprises the following steps of preparing for materials, washing the materials, pre-hydrolyzing, cooking, washing, selecting, bleaching, regulating the polymerization degree, dechlorinating and acid-treating. According to the method, after the cooking stage is finished, the obtained pulp has alpha cellulose content of not less than 95%, pentosan of not more than 4% and average polymerization degree of 550-700; and after the acid treating is finished, the obtained pulp has alpha cellulose content of not less than 93%, pentosan content of not more than 4.0%, average polymerization degree of 500-650 and whiteness of 82-86%. The processes of full liquid phase hydrolysis, full liquid phase cooking, hydrolysate recycling, recycled black liquor displacement cooking and chlorine dioxide clean bleaching are adopted in the method disclosed by the invention. The method has the characteristics of high whiteness, low viscosity and high polymerization degree of products, thus wastewater pollution is greatly reduced, the temperature rise time and steam are saved, the triple effects of energy saving, emission reduction and production increasing are achieved, and the problems of large wastewater pollution, high energy consumption and low capacity existing in the traditional pre-hydrolytic sulfate method for preparing pulp.

Description

technical field

[0001] The invention belongs to the technical field of chemical fibers, and in particular relates to a method for preparing bamboo pulp by full-liquid phase prehydrolysis sulfate replacement cooking. Background technique

[0002] In recent years, as the global energy shortage problem has become increasingly prominent, the prices of non-renewable resources such as coal and oil have continued to rise, causing the price of petrochemical synthetic fibers to rise. Therefore, looking for renewable fibers has become a new trend in the future. Although cotton-like natural fibers have excellent spinnability and regeneration properties, their prices are still rising due to limited production capacity, which is far from meeting the huge fiber market demand. Therefore, another type of renewable fiber - viscose fiber is emerging and has become the mainstream of recycled fiber.

[0003] In the viscose fiber category, the viscose fiber produced by dissolving spinning techn...

Examples

Embodiment 1

[0021] Material preparation: Bamboo is cut into 20-50mm long rectangular bamboo slices by a bamboo cutting machine, and the pass rate is required to reach more than 80%.

[0022] Washing: The bamboo slices are washed by a washing machine to remove surface impurities and excess water, and then enter the cooking pot.

[0023] Pre-hydrolysis: After washing, the bamboo chips are packed in a pot according to the packing density of 200kg / m3, and then the hydrolysis medium is filled into the cooking pot. Keep at 165°C for 180 minutes. After the hydrolysis is completed, the hydrolyzate is pumped into the hydrolyzate storage tank as the next pot of hydrolysis medium.

[0024] Cooking: using sulfate full liquid phase cooking. The amount of alkali used is Na 2 O is 22% to the absolute dry bamboo weight, and the degree of sulfidation is based on Na 2 O is 25%, rising to 160°C for 120 minutes, discharging after completion of terminal replacement, yielding a slurry yield of 34%, a cellul...

Embodiment 2

[0031] Material preparation: Bamboo is cut into 20-50mm long rectangular bamboo slices by a bamboo cutting machine, and the pass rate is required to reach more than 80%.

[0032] Washing: The bamboo slices are washed by a washing machine to remove surface impurities and excess water, and then enter the cooking pot.

[0033] Pre-hydrolysis: after washing, the bamboo chips are packed in a pot according to the packing density of 200kg / m3, and then the cooking pot is filled with hydrolysis medium and then the temperature is raised. Keep at ℃ for 180 minutes. After the hydrolysis is completed, the hydrolyzate is pumped into the hydrolyzate storage tank as the next pot of hydrolysis medium.

[0034] Cooking: using sulfate full liquid phase cooking. The amount of alkali used is Na 2 O is 22% to the absolute dry bamboo weight, and the degree of sulfidation is based on Na 2 O is 25%, rising to 165°C for 140 minutes, discharging after completion of terminal replacement, yielding a sl...

Embodiment 3

[0041] Material preparation: Bamboo is cut into 20-50mm long rectangular bamboo slices by a bamboo cutting machine, and the pass rate is required to reach more than 80%.

[0042] Washing: The bamboo slices are washed by a washing machine to remove surface impurities and excess water, and then enter the cooking pot.

[0043]Pre-hydrolysis: After washing, the bamboo chips are packed in a pot according to the packing density of 200kg / m3, and then the cooking pot is filled with hydrolysis medium and then the temperature is raised. The temperature is kept at 120 minutes. After the hydrolysis is completed, the hydrolyzate is pumped into the hydrolyzate storage tank as the next pot of hydrolysis medium.

[0044] Cooking: using sulfate full liquid phase cooking. The amount of alkali used is Na 2 O is 20% of the absolute dry bamboo weight, and the degree of sulfidation is based on Na 2 O is 20%, rise to 170°C and hold for 120 minutes, discharge after completion of end-point replacem...

technical field

[0001] The invention belongs to the technical field of chemical fibers, and in particular relates to a method for preparing bamboo pulp by full-liquid phase prehydrolysis sulfate replacement cooking. Background technique

[0002] In recent years, as the global energy shortage problem has become increasingly prominent, the prices of non-renewable resources such as coal and oil have continued to rise, causing the price of petrochemical synthetic fibers to rise. Therefore, looking for renewable fibers has become a new trend in the future. Although cotton-like natural fibers have excellent spinnability and regeneration properties, their prices are still rising due to limited production capacity, which is far from meeting the huge fiber market demand. Therefore, another type of renewable fiber - viscose fiber is emerging and has become the mainstream of recycled fiber.

[0003] In the viscose fiber category, the viscose fiber produced by dissolving spinning techn...

Examples

Embodiment 1

[0021] Material preparation: Bamboo is cut into 20-50mm long rectangular bamboo slices by a bamboo cutting machine, and the pass rate is required to reach more than 80%.

[0022] Washing: The bamboo slices are washed by a washing machine to remove surface impurities and excess water, and then enter the cooking pot.

[0023] Pre-hydrolysis: After washing, the bamboo chips are packed in a pot according to the packing density of 200kg / m3, and then the hydrolysis medium is filled into the cooking pot. Keep at 165°C for 180 minutes. After the hydrolysis is completed, the hydrolyzate is pumped into the hydrolyzate storage tank as the next pot of hydrolysis medium.

[0024] Cooking: using sulfate full liquid phase cooking. The amount of alkali used is Na 2 O is 22% to the absolute dry bamboo weight, and the degree of sulfidation is based on Na 2 O is 25%, rising to 160°C for 120 minutes, discharging after completion of terminal replacement, yielding a slurry yield of 34%, a cellul...

Embodiment 2

[0031] Material preparation: Bamboo is cut into 20-50mm long rectangular bamboo slices by a bamboo cutting machine, and the pass rate is required to reach more than 80%.

[0032] Washing: The bamboo slices are washed by a washing machine to remove surface impurities and excess water, and then enter the cooking pot.

[0033] Pre-hydrolysis: after washing, the bamboo chips are packed in a pot according to the packing density of 200kg / m3, and then the cooking pot is filled with hydrolysis medium and then the temperature is raised. Keep at ℃ for 180 minutes. After the hydrolysis is completed, the hydrolyzate is pumped into the hydrolyzate storage tank as the next pot of hydrolysis medium.

[0034] Cooking: using sulfate full liquid phase cooking. The amount of alkali used is Na 2 O is 22% to the absolute dry bamboo weight, and the degree of sulfidation is based on Na 2 O is 25%, rising to 165°C for 140 minutes, discharging after completion of terminal replacement, yielding a sl...

Embodiment 3

[0041] Material preparation: Bamboo is cut into 20-50mm long rectangular bamboo slices by a bamboo cutting machine, and the pass rate is required to reach more than 80%.

[0042] Washing: The bamboo slices are washed by a washing machine to remove surface impurities and excess water, and then enter the cooking pot.

[0043]Pre-hydrolysis: After washing, the bamboo chips are packed in a pot according to the packing density of 200kg / m3, and then the cooking pot is filled with hydrolysis medium and then the temperature is raised. The temperature is kept at 120 minutes. After the hydrolysis is completed, the hydrolyzate is pumped into the hydrolyzate storage tank as the next pot of hydrolysis medium.

[0044] Cooking: using sulfate full liquid phase cooking. The amount of alkali used is Na 2 O is 20% of the absolute dry bamboo weight, and the degree of sulfidation is based on Na 2 O is 20%, rise to 170°C and hold for 120 minutes, discharge after completion of end-point replacem...