CN102561079A

CN102561079A - Sulfate pulping method for compressed bamboo chips

Info

Publication number: CN102561079A
Application number: CN201110442216XA
Authority: CN
Inventors: 吴晨; 葛少章; 葛少朝; 田超; 曹春昱; 聂怡; 杨小博
Original assignee: BEIJING CHENFENG INVESTEMENT HOLDINGS CO LTD; China National Pulp and Paper Research Institute
Current assignee: Beijing Chenfeng Investement Holdings Co.,Ltd.
Priority date: 2011-12-27
Filing date: 2011-12-27
Publication date: 2012-07-11
Anticipated expiration: 2031-12-27
Also published as: CN102561079B

Abstract

The invention discloses a method for compressing papermaking bamboo chips into square blocks facilitating transportation and then implementing sulfate pulping, and relates to a drying and compression method for bamboo chips and a sulfate pulping technology for the compressed bamboo chips. The bamboo chips are compressed into high-density cubes by a mechanical method, so that the problems of small volume weight, low transport efficiency, large storage space and the like of bulk bamboo chips are solved; and a specific sulfate pulping process scheme is provided for the compressed bamboo chips, so that the pulp forming quality of the compressed bamboo chips is ensured. The volume of the compressed bamboo chips is reduced to below 1/3 of the volume of the naturally stacked non-compressed bamboo chips; under the same sulfate digestion process condition, the sieve residue rate of the formed pulp is reduced by 20 to 40 percent; and when the bamboo chips are beaten to the same beating degree, the beating time is shortened by 15 to 30 percent, and the beating energy consumption can be obviously reduced.

Description

A kind of sulfate pulping method of compressing bamboo chip

Technical field

The invention belongs to the pulping and paper-making field, is a kind of the paper grade (stock) bamboo chip to be compressed into the method that the square of being convenient to transport carries out sulfate pulping then, relates to oven dry and the compression method of bamboo chip, the sulfate pulping technology of compression bamboo chip.

Background technology

Along with the develop rapidly and the reinforcement of country to natural forest protection of resources dynamics of China's pulping and paper-making industry, the sufficient supplies that how to satisfy paper making raw material has become the strategic problem that concerns China's enterprises in pulp and paper industry living or death.Bamboo is exactly a kind of important pulping and paper-making raw material since ancient times, and regional reserves such as each province and South Asia, the South Asian Subcontinent are huge on the south China the Changjiang river.But, add that the natural bulk density of bamboo chip is less, so a poor efficiency of bamboo chip transportation becoming again, expensive process because mostly the above-mentioned bamboo place of production be the mountain area or the network of waterways in length and breadth.How improving efficient, the reduction raw material cost of transportation of bamboo chip transportation, is the difficult problem that enterprises in pulp and paper industry is anxious for solution.

Though bamboo has higher density in natural plants; But it is as a kind of plant tissue; To sustain damage inevitably during through powerful mechanical compress, thereby its pulping and paper-making performance will be produced certain influence, how negative effect reduced to minimum; Guaranteeing that enterprises in pulp and paper industry produces qualified slurry paper product, also is the key point that can the compression bamboo chip obtain the industry approval.

The object of the invention is to solve difficult problems such as bamboo chip unit weight in bulk is little, conevying efficiency is low, memory space is big, simultaneously the bamboo chip through mechanical compress is proposed sulfate pulping process program targetedly, guarantees the pulp quality of compression bamboo chip.

Summary of the invention

After bamboo chipped, make it become the high density cuboid of regular shape from loose low unit weight state through oven dry, compression, carry out slurrying with sulfate process then, specific embodiments is following:

(1) gets the raw materials ready:, screen out wherein disintegrating slag and silt the bamboo chip of bamboo with chipping machine cutting growth 15～30mm, wide 20～30mm size;

(2) oven dry: with bamboo chip with rotary drying kiln or mesh-belt drier at 70～230 ℃ of oven dry 20～40min down, to the bamboo chip moisture content be 10～20%;

(3) compression: the bamboo chip after will drying with full-automatic extruder at 400～1000kg/cm ²The pressure lower compression grow into 150-340mm, wide for 75-340mm, high be the cuboid of 60-140mm;

(4) boiling: adopt sulfate process that the compression bamboo chip is carried out boiling, (percentage that is equivalent to the over dry raw material weight is in NaOH for total alkali consumption 15～22%; Down together); Sulphidity 15～30%, liquor ratio 1: 6～1: 2.5,150～175 ℃ of maximum temperatures; Heating-up time 120～250min, temperature retention time 80～180min;

(5) making beating: the NBSK to the compression bamboo chip is pulled an oar, and beating consistency, following cutter weight are principle to reduce fibre cutting as far as possible.

Compare with traditional bamboo chip sulfate pulping technology, characteristics of the present invention are:

(1) bamboo chip is through after oven dry and compressing; When volume reduces to the nature accumulation 1/3～1/4 can significantly be dwindled transportation and memory space, improves conevying efficiency, reduced cost of transportation, and the block-shaped rule of compressed bamboo; Pile up easily and pile up, also can improve the operating efficiency of short-haul operation.

(2) bamboo chip by enough mechanism compression moulding, does not add any adhesive fully, and natural environment is not increased any pollution, can expand behind the bamboo piece chance water at once and scatter, and need not to increase the relevant equipment that cracks.

(3) bamboo chip is through after the mechanical presses, and original physical arrangement receives destruction to a certain degree, for the infiltration of digestion process herb liquid provides advantage, boiling screening reject rate is obviously reduced, the boiling of this bamboo material of will going a long way greatly.Based on same reason, reaching under the prerequisite of identical pulping hardness number, the comparable bamboo chip that do not compress of boiling of compression bamboo chip is practiced thrift a certain amount of chemicals, can reduce the pollutional load of slurrying cost and pulping waste liquor like this.

(4) owing to original cell membrane interlayer structure after absorbing mechanical energy is damaged; The NBSK of compression bamboo chip is done the time spent and can be realized the outer field wire-dividing broom purification of abolishing with internal layer of cell membrane receiving less making beating; Beating time obviously shortens, and is very beneficial for the reduction of beating energy consumption.

(5) with the compressed bamboo piece be the sulfate pulping of raw material, only need finely tune, need not to change production equipment and technological process, can not bring investment risk for enterprises in pulp and paper industry to pulping chemical consumption and beating process parameter

Description of drawings

Fig. 1 is a bamboo chip compression pulping process flow of the present invention, and Fig. 2 is traditional bamboo chip pulping process flow.

Embodiment

Sinocalamus latiflorus and mao bamboon to represent thin-walled class bamboo wood and heavy wall class bamboo wood respectively are raw material, and compression bamboo chip and the sulfate pulping performance of not compressing bamboo chip are compared, and explain for the present invention does more specifically:

Embodiment 1

The process conditions that the sinocalamus latiflorus bamboo chip is dried, compressed: get the sinocalamus latiflorus bamboo chip, under 105 ℃, dry to moisture content be 15%, then at 500kg/cm ²Pressure under the sinocalamus latiflorus bamboo chip is compressed into the cuboid of 15cm * 7.5cm * 6cm.

Respectively pressure contract with unpressed sinocalamus latiflorus bamboo chip 2kg (over dry) carry out sulfate pulping with following process conditions: total alkali 16%, sulphidity 25%, solid-to-liquid ratio 1: 4; 170 ° of maximum temperatures; Heating-up time 120min, temperature retention time 120min, screening sieve seam 0.35mm.

Pulping adopts Valley beater making beating, beating consistency 1.7%, and 45 ± 2 ° of SR of target beating degree, the making beating back is used Germany to produce the Rapid-Kothen page device of embarking on journey and is copied the system handsheet, quantitatively 60g/m ², 97 ℃ of bake out temperatures, the sheet pulp performance all detects according to the paper industry standard method.

Under identical conditions of cooking, the compression bamboo chip is as shown in table 1 with the pulpability contrast of not compressing bamboo chip.

Table 1

Visible by table 1, bamboo chip through oven dry and compression after, 0.28 air dried tonne/m that transportation unit weight can be when not compressing ³Be increased to 0.93 air dried tonne/m ³, transportation volume has reduced 70%; Under identical kraft cooking process conditions, the pulping screening reject rate of compression bamboo chip does not reduce 27% than compressing bamboo chip, and permanganate number descends 2.1, and whiteness improves 2.35 units, becomes the pulp yield loss very little; When pulling an oar to 45 ± 2 ° of SR equally, the beating time of compression bamboo chip NBSK does not shorten 24% than compressing bamboo chip, and the sheet pulp performance does not have marked change simultaneously.

Embodiment 2

The process conditions that bamboo chip to mao bamboon is dried, compressed: get the mao bamboon bamboo chip, under 120 ℃, dry to moisture content be 10%, then at 600kg/cm ²Pressure press down the cuboid that shortens 15cm * 7.5cm * 6cm into.

The bamboo chip 2kg (over dry) that contracts with uncompressed of pressure carries out sulfate pulping with following conditions respectively; Total alkali 18%, sulphidity 25%, solid-to-liquid ratio 1: 5,170 ° of maximum temperatures, heating-up time 110min, temperature retention time 100min, screening, sieve seam 0.35mm.

Pulping adopts Valley beater making beating, and 45 ± 2 ° of SR of beating degree use Germany to produce the Rapid-Kothen page device of embarking on journey and copy the system handsheet, quantitatively 60g/m ², 97 ℃ of bake out temperatures, the sheet pulp performance all detects according to the paper industry standard method.

Experimental result is as shown in table 2.

Visible by table 2, bamboo chip is through after oven dry and compressing, and transportation unit weight is by 0.25 original air dried tonne/m ³Below bring up to 0.94 air dried tonne/m ³, transportation volume has reduced 73%; Under identical kraft cooking process conditions, the pulping screening reject rate of compression bamboo chip does not reduce 36% than compressing bamboo chip, and permanganate number descends 1.2, and whiteness improves 1.32 units, becomes the pulp yield loss less; When pulling an oar to 45 ± 2 ° of SR equally, the beating time of compression bamboo chip NBSK does not shorten 25% than compressing bamboo chip, and other performances do not have marked change.

Claims

1. sulfate pulping method of compressing bamboo chip; It is characterized in that, after bamboo is chipped, make it become the high density cuboid of regular shape from loose low-density state through oven dry and mechanical compress; Carry out slurrying with sulfate process then, specifically may further comprise the steps:

(1) gets the raw materials ready: the bamboo raw material is cut into the qualified wood chip of size with chipping machine, screen out wherein disintegrating slag and silt;

(2) oven dry: bamboo chip is dried 20～40min with rotary drying kiln or mesh-belt drier down at 70-230 ℃, make bamboo chip moisture content optimum carry out mechanical compress;

(3) compression: the bamboo chip after will drying with full-automatic extruder at 400-1000kg/cm ²Lower compression grow into 150-340mm, wide for 75-340mm, high be the cuboid of 60-140mm;

(4) boiling: adopt sulfate process that the compression bamboo chip is carried out boiling; Total alkali consumption 15～22% (percentage that is equivalent to the over dry raw material weight is in NaOH), sulphidity 15～30%; Liquor ratio 1: 6～1: 2.5; 150～175 ℃ of maximum temperatures, heating-up time 120～250min, temperature retention time 80～180min;

2. a kind of sulfate pulping method of compressing bamboo chip as claimed in claim 1 is characterized in that, bamboo raw material described in the step (1) is cizu, sinocalamus latiflorus, presss from both sides in bamboo, bambusa textile, green bamboo, red bamboo, mao bamboon and the huge bamboo any one in vain.

3. a kind of sulfate pulping method of compressing bamboo chip as claimed in claim 1 is characterized in that the temperature that bamboo chip is dried in step (2) is 100～180 ℃, and the moisture content that the bamboo chip optimum carries out mechanical compress is 10～20%.

4. a kind of sulfate pulping method of compressing bamboo chip as claimed in claim 1 is characterized in that, to be compressed the mechanical pressure of moulding be 400～1000kg/cm to bamboo chip in step (3) ²

5. a kind of sulfate pulping method of compressing bamboo chip as claimed in claim 1 is characterized in that, the NBSK making beating principle of compression bamboo chip is high dense, heavy beating in step (5).