CN103321080A - ECF bleaching technology of fast growing poplar by sulfate pulp bio-chemical method - Google Patents

Abstract

The invention discloses an ECF bleaching technology of fast growing poplar by a sulfate pulp bio-chemical method. The technology provided by the invention is characterized by comprising the following steps: (1) boiling: taking fast growing poplar chips, stewing the fast growing poplar chips in a digester to obtain virgin pulp, washing, and screening to obtain paper pulp; (2) xylanase pretreatment; and (3) ECF bleaching: bleaching the above paper pulp which has undergone enzyme treatment, wherein the bleaching process is one of three bleaching processes, namely ODQP, OPDQP or O1O2PDQP. According to the invention, xylanase is used to pretreat the paper pulp, and one of the three bleaching processes, namely ODQP, OPDQP or O1O2PDQP, is carried out for bleaching so as to obtain the paper pulp with higher whiteness and viscosity. In comparison with paper pulp which is directed bleached without xylanase pretreatment, the paper pulp produced by the ECF bleaching technology has the following advantages: beating whiteness loss is less, folding strength is averagely higher by 40 times, burst index is averagely higher by 0.45N.m.g<-1>, breaking length is averagely higher by 0.35KM, and tear index difference is very little.

Description

The sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar

Technical field

The present invention relates to the sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar, belong to pulp technology for making paper.

Background technology

The fast-growing poplar is the chief species that the northern area of China woods paper My Perspective On The Co-building adopts, belong to the fast-growing leaf wood, they have fast growth, strong adaptability, the nature whiteness is high, material loose, the absorbability of liquid is good, and lignin content is lower, and the content of cellulose and hemicellulose is higher, can be used for producing chemical pulp, semi-chemical pulp and mechanical pulp etc., is one of main high-quality paper making raw material of northern China.The fast-growing poplar in Northern Europe, the northern area of North America and China is widely cultivated, it has comprised a plurality of kinds, representational have black poplar, Triploid of Populus Tomentosa, a middle forest poplar etc., the growth characteristic of these fast-growing poplars, constituent are all very approaching.

In recent years, the high yield pulp development is swift and violent, and refining energy consumption is large, the shortcomings such as pulping intensity is lower and retention of whiteness is poor, easy brightness reversion but high yield pulp exists, and causes high yield pulp to be difficult to the paper that some paper strengths are high, be difficult for brightness reversion, Heat stability is good of manufacturing paper with pulp.Therefore within the from now on quite a long time, the manufacture paper with pulp superiority of high-grade paper of chemical pulp can not become.The fast-growing poplar is as a kind of good paper making raw material, its yield of producing chemical pulp is higher, generally about 51%, and the own whiteness of fast-growing poplar is high, through the former pulp brightness behind the chemical pulping generally about 30%ISO, former pulp brightness than other leaf woods exceeds about 3-5%ISO, and the fast-growing poplar is as a kind of broad-leaved wood paper making raw material of high-quality, the black liquor that produces in its digestion process, ripe treatment technology has been arranged, can be to environment.

Fast-growing poplar chemical pulp is to adopt chemical agent, under specific conditions of cooking, with the most of lignin stripping in the plant fiber material, keep cellulose and the paper pulp of the reservation hemicellulose of different degree as much as possible.The yield of chemical pulp is relatively low, and generally between 40-55%, but the content of cellulose in the chemical pulp is high, paper strength greatly, easily bleach, be difficult for brightness reversion, good endurance.Therefore adopt the biological enzyme formulation bio-bleaching to bleach the Bleaching Technology that combines with chemical method, the low oligosaprobic chemical pulp production technology of the easy beating energy consumption of high-whiteness high-strength of preparation fast-growing poplar is one of important channel of China's pulping and paper-making development.

Summary of the invention

For above-mentioned prior art, the objective of the invention is to change the technique of traditional pure chemistry method association with pulp bleaching, the technique that adopts bio-bleaching to combine with chemical bleaching, when reaching identical pulp brightness, thereby the chemical bleaching liquor that consumes still less further reduces bleaching waste liquor to the pollution of environment, when perhaps consuming identical chemical bleaching liquor, makes the more Gao Gengyi making beating of whiteness of paper pulp, further reduce the beating energy consumption of paper pulp, realize the low consumption high efficiency bleaching of fast-growing poplar sulfate pulp.

The present invention is achieved by the following technical solutions: the concentration of following related slurry is mass percent if no special instructions; Related reagent, the consumption of medicine if no special instructions, all are for oven dry stock.

The sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar, step is as follows:

(1) boiling: get the quick growth poplar wood sheet, put into the digester boiling, get magma, then wash fully, screen, get paper pulp, the Kappa number of paper pulp is 16～21;

(2) xylanase pretr eatment;

(3) ECF bleaching: the above-mentioned paper pulp of processing through enzyme is bleached, and bleaching process is ODQP, O _PDQP or O ₁O _2PThree kinds of DQP float one of order, and the step of bleaching process is: at first, the paper pulp of processing through enzyme is carried out the deoxidation lignin or strengthens the deoxidation lignin; Oxygen delignification washs paper pulp after finishing, and then carries out D section ClO 2 bleaching; D section ClO 2 bleaching washs paper pulp after finishing, and then carries out Q section chelation treatment; Q section chelation treatment is washed paper pulp after finishing, and then carries out P section H ₂O ₂Bleaching is finished.

Further, the concrete mode of described boiling is: the quick growth poplar wood sheet of getting length 15～25mm, width 10～20mm, thickness 3～5mm, behind the natural air drying, in 15L electric heating rotating autoclave, carry out boiling, make fast-growing poplar sulfate magma, the condition of boiling is: alkali charge 20%(is to over dry raw material, Na ₂The O meter), sulphidity 24%, liquor ratio 1:4,165 ℃ of boiling maximum temperatures are carried out little venting 15min, heating-up time 120min, temperature retention time 90min in the time of 105 ℃; Fully wash after the boiling, screen, get paper pulp, the Kappa number of paper pulp is 16～21.

Further, the concrete mode of described xylanase pretr eatment is: adjusting pulp density is 10%, then uses zytase X ₁, X ₂Or X ₃Process, in processing procedure, every interval 10～15min rubs once, to guarantee that enzyme mixes with the even of paper pulp; Take out after processing, put into boiling water bath 10min, make zytase inactivation cessation reaction, with entering next step bleaching process behind the running water cleaning paper pulp.

Described zytase X ₁Provide (the letter zytase Pulpzyme HC of trade name Novi, article number CKN00117 and CDN00429) by Novozymes Company, liquid state, the cellulose-less enzyme is lived; Zytase X ₂, X ₃Biological Co., Ltd provides (trade name zytase, article number LV-1 and LV-2) by the green little health in Shenzhen, is the white powder solid, and all cellulase is not lived.

Described zytase X ₁, X ₂Or X ₃The concrete technology condition of processing is as follows: X ₁The process conditions of processing: enzyme dosage 8IU/L(is for the cumulative volume of paper pulp), 50～55 ℃ of temperature, pH8, time 120min; X ₂The process conditions of processing: enzyme dosage 6IU/g(is for the quality of exhausted paper pulp), 55～60 ℃ of temperature, pH8～9, time 120min; X ₃The process conditions of processing: enzyme dosage 8IU/g(is for the quality of exhausted paper pulp), temperature 50 C, pH8～9, time 120min.

Further, the concrete mode of described ODQP bleaching process is: Oxygen Delignification of Fast-Growing is: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 80min, MgSO ₄Consumption 0.5%; D section: ClO ₂Consumption is 0.7%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA(Chinese diethylene triamine pentacetic acid (DTPA)) consumption 0.5%, temperature 70 C, time 60min, pH value 4～5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

Further, described O _PThe concrete mode of DQP bleaching process is: strengthening the Oxygen Delignification of Fast-Growing condition is: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, MgSO ₄Consumption 0.5%, Na ₂SiO ₃Consumption 0.7%, H ₂O ₂Consumption 3%, time 80min; D section: ClO ₂Consumption is 0.5%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA consumption 0.5%, temperature 70 C, time 60min, pH value 4-5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

Further, described O ₁O _2PThe concrete mode of DQP bleaching process is: first paragraph oxygen delignification and second segment are strengthened the process conditions of oxygen delignification: first paragraph O ₁: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 20min, MgSO ₄Consumption 0.5%; Second segment O _2P: replenish 0.5% NaOH, add 3% H ₂O ₂, Na ₂SiO ₃Consumption 0.7%, oxygen is pressed 0.5MPa, time 60min; D section: ClO ₂Consumption is 0.5%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA consumption 0.5%, temperature 70 C, time 60min, pH value 4-5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

The present invention adopts zytase that paper pulp is carried out preliminary treatment, then by ODQP, O _PDQP or O ₁O _2PThree kinds of DQP float one of order and bleach, and have obtained the higher paper pulp of whiteness and viscosity, (X refers to xylanase pretr eatment) specific as follows:

XODQP floats order at ClO ₂In the situation of total consumption 0.7%, the whiteness of bleached pulp is up to 87.0%ISO, minimum 86.5%ISO; The whiteness of ODQP bleached pulp is 84.5%ISO, through enzyme process than not with enzyme process float after the whiteness of slurry exceed 2.0-2.5%ISO, and kept higher pulp viscosity and lower Kappa number.

XO _PDQP floats order at ClO ₂Total consumption 0.5%, H ₂O ₂In the situation of total consumption 5%, the whiteness of bleached pulp is up to 89.7%ISO, minimum 89.3%ISO; O _PThe whiteness of DQP bleached pulp is 87.2%ISO, through enzyme process than not with enzyme process float after the whiteness of slurry exceed 2.1-2.5%ISO, and kept higher pulp viscosity and lower Kappa number; This floats the ClO of order ₂Consumption further reduces, and more meets environmental requirement.

XO ₁O _2PDQP floats order at ClO ₂Total consumption 0.5%, H ₂O ₂In the situation of total consumption 5%, the whiteness of bleached pulp is up to 89.6%ISO, minimum 89.2%ISO; O ₁O _2PThe whiteness of DQP bleached pulp is 87.1%ISO, through enzyme process than not with enzyme process float after the whiteness of slurry exceed 2.1-2.5%ISO, and kept higher pulp viscosity and lower Kappa number; This floats the ClO of order ₂Consumption further reduces, and more is conducive to environmental protection.

With respect to not using xylanase pretr eatment, directly bleach for the paper pulp that obtains, making beating loss of whiteness value of the present invention still less, folding strength on average exceeds 40 times, burst index on average exceeds 0.45Nmg ^-1, fracture length on average exceeds 0.35KM, and it is very little that tear index differs.The present invention has also compared the correspondence of three kinds of xylanase treatment paper pulp and has floated the bleaching effect of order, and find: the effect of the pulp treatment of three kinds of enzymes is difference to some extent, from the initial effect that affects oxygen delignification, has influence on the bleaching results that ECF respectively floats order always.Wherein help float effect best be X ₂, secondly be X ₁, be X at last ₃But on the whole, these three kinds of enzymes helps that to float effect all apparent in view.When reaching identical or close beating degree, the former required making beating revolution still less can be saved beating energy consumption about 20%.

Description of drawings

Fig. 1: KP magma fiber properties schematic diagram.

Fig. 2: through zytase X ₁The paper pulp fiber characteristic schematic diagram of processing.

Fig. 3: through zytase X ₂The paper pulp fiber characteristic schematic diagram of processing.

Fig. 4: through zytase X ₃The paper pulp fiber characteristic schematic diagram of processing.

Fig. 5: the AFM two dimensional image of fast-growing poplar KP slurry.

Fig. 6: fast-growing poplar X ₁The AFM two dimensional image of ODQP slurry.

Fig. 7: fast-growing poplar X ₂The AFM two dimensional image of ODQP slurry.

Fig. 8: the AFM 3-D view of fast-growing poplar KP slurry.

Fig. 9: fast-growing poplar X ₁The AFM two dimensional image of ODQP slurry.

Figure 10: fast-growing poplar X ₂The AFM two dimensional image of ODQP slurry.

The specific embodiment

The present invention is further illustrated below in conjunction with embodiment.The conventional method in field under the method for detailed description is not among the embodiment, raw materials used, reagent etc. is existing product in the prior art.

The process optimization of embodiment 1 xylanase treatment fast-growing poplar sulfate pulp

Zytase is a kind of protein with single-minded catalytic, and it is stricter to the requirement of environment, that is to say that each enzyme has its specific optimal environmental condition.Zytase is all being obtained obvious effect aspect chemical pulping and the bleaching preliminary treatment.According to pertinent literature, the factor that affects xylanase pretr eatment mainly contains enzyme dosage, temperature, pH value and time etc., and these factors have in various degree impact to oxygen delignification effect and follow-up bleaching.In these influence factors, temperature is relevant with the characteristic of zytase itself with the pH value, and relatively less to the property effect of slurry.This experiment is inquired into the only preliminary treatment fast-growing of different xylanase preparations poplar sulfate pulp process conditions by the conversion experiment condition.

The below adopts identical Oxygen Delignification of Fast-Growing condition when different xylanase preparations is discussed in consumption, temperature, pH value, the optimum value of time, this is with reference in the past better oxygen delignification condition: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 80min, MgSO ₄All drug dosages of consumption 0.5%(are all for oven dry stock, and are as follows).

The used raw material sources of this experiment are:

Experiment is to mix the quick growth poplar wood sheet with the quick growth poplar wood sheet, takes from Shandong sun Paper Co., Ltd.Chip dimensions length 15-25mm, width 10-20mm, thickness 3-5mm, the qualification rate of wood chip is more than 90%, and is after wood chip is fetched from the stock ground, for subsequent use behind the natural air drying equilibrium water conten.

Zytase X ₁Provided by Novozymes Company, liquid state, the cellulose-less enzyme is lived; Zytase X ₂, X ₃All have Shenzhen biological Co., Ltd of green little health to provide, be the white powder solid, all cellulase is not lived.

During experiment, the fast-growing poplar is carried out boiling, obtain paper pulp after, carry out again xylanase pretr eatment.Digestion process is: carry out boiling in 15L electric heating rotating autoclave, make fast-growing poplar sulfate magma.The condition of boiling is: alkali charge 20%(is to over dry raw material, Na ₂The O meter), sulphidity 24%, liquor ratio 1:4,165 ℃ of boiling maximum temperatures are carried out little venting 15min, heating-up time 120min, temperature retention time 90min in the time of 105 ℃.The boiling disposed slurry is through fully washing, screening.Paper pulp yield 49.3%, the Kappa number 18.5 of paper pulp, viscosity 842.7mL/g, whiteness 36.5%ISO.

Behind the xylanase pretr eatment, carry out oxygen delignification, the oxygen delignification experiment is carried out in JF-DSTE polymerization reaction kettle (have and stir and the automatic constant-temperature function).Its Oxygen Delignification of Fast-Growing is: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 80min, MgSO ₄Consumption 0.5%.

1.1 the consumption of zytase is on the impact of fast-growing poplar sulfate pulp oxygen delignification

In order to obtain best enzyme treatment effect, the consumption of zytase must carry out optimization selection.This is because the content of different paper pulp kind xylans is different, the xylan content of hardwood pulp is higher than the content of softwood pulp, xylan content such as Eucalyptus Kraft Pulp is higher than masson s pine pulp, and xylan is easier to be reached, so the consumption of enzyme is less, in the situation that pH value and temperature suit, the consumption with zytase of greater activity just lacks than common zytase consumption.Starch the low required enzyme dosage of dense mistake and also want corresponding increase.Therefore, the effect that how much affects enzyme processing fast-growing poplar sulfate pulp oxygen delignification of zytase consumption, affect whiteness and the Kappa number of oxygen delignification paper pulp, also affect following bleaching effect and the production cost of paper pulp behind the oxygen delignification, the consumption of therefore inquiring into three kinds of different zytases has important practical significance.Three kinds of Novel xylanase X ₁, X ₂, X ₃The consumption experimental studies results see Table 1,2,3.

Table 1 zytase X ₁Consumption is on the impact of the oxygen delignification performance of pretreating paper pulp

Annotate: zytase X ₁Other conditions of processing: 55 ℃ of temperature, time 120min, starch dense 10%, pH value 8-9.

As can be seen from Table 1, along with zytase X ₁The increase of consumption, the whiteness of the paper pulp behind the oxygen delignification tends towards stability after progressively increasing, and the Kappa number of paper pulp reduces amplitude and no longer changes from large to small, and the viscosity of paper pulp descends after rising to some extent first slightly, as zytase X ₁When consumption was 8IU/L, the better effects if of oxygen delignification was a little.Can find out from the experimental data of table 1, compare than untreated paper pulp through the paper pulp of xylanase treatment, the whiteness of paper pulp raises and viscosity also slightly raises, and the pulp property behind the oxygen delignification increases.

Table 2 zytase X ₂Consumption is on the impact of the oxygen delignification performance of pretreating paper pulp

Annotate: zytase X ₂Other conditions of processing: temperature 50 C, time 120min, starch dense 10%, pH value 8-9.

As can be seen from Table 2, along with zytase X ₂The increasing of consumption, the whiteness of paper pulp progressively increases behind the oxygen delignification, and when waiting zytase to be increased to 10IU/g, pulp brightness no longer changes; The viscosity of paper pulp increases first and tends towards stability afterwards and slightly reduce; The Kappa number of paper pulp reduces amplitude with the increase of zytase consumption and strengthens first and be tending towards afterwards constant.It can also be seen that from table 2, as zytase X ₂When consumption was 6IU/g, the performance of paper pulp was best behind the oxygen delignification.

Table 3 zytase X ₃Consumption is on the impact of the oxygen delignification performance of pretreating paper pulp

Annotate: zytase X ₃Other conditions of processing: temperature 50 C, time 120min, starch dense 10%, pH value 8-9.

As can be seen from Table 3, along with zytase X ₃The increase of consumption, the whiteness of paper pulp raises first and is tending towards afterwards constant behind the oxygen delignification; The Kappa number of paper pulp descends first to tending towards stability afterwards and no longer changes; The viscosity elder generation of the paper pulp to some extent rear increasing degree of increase slows down and tends towards stability.It can also be seen that from table 3, work as X ₃When consumption was 8IU/g, the performance improvement effect of the paper pulp behind the oxygen delignification was best.

Can find out from table 1,2,3, three kinds not the cellulase zytase of living when improving the pulp oxygen delignification performance, show some common characteristics: along with the increase of enzyme dosage, the whiteness of paper pulp progressively improves, and finally can improve pulp brightness 1.3-1.5%ISO; The Kappa number of paper pulp reduces amplitude at 1-1.2; The viscosity rise amplitude of paper pulp is about 30mL/g.The improvement of oxygen delignification pulp property provides good precondition to the improvement of follow-up bleached pulp performance behind the xylanase treatment.Simultaneously, because the production unit of three kinds of zytases and technique is different, when having caused three kinds of enzyme pulp treatment, produce an effect is also incomplete same, is mainly manifested in: when reaching the same treatment effect, the consumption of enzyme is different.

1.2 reaction temperature is on the impact of fast-growing poplar sulfate pulp oxygen delignification

Zytase is a kind of biocatalyst, and in certain active temperature scope, the reaction speed of enzyme and paper pulp is accelerated along with the rising of temperature, if temperature reduces, then its reaction speed descends.But when temperature surpasses a certain boundary, the activity decreased of enzyme even inactivation.Generally speaking, the effect of zytase and paper pulp mainly contains two aspects: the one, and when temperature raise, the speed of reaction was accelerated, and the 2nd, along with the rising enzyme of temperature loses activity gradually, so that the functioning efficiency of the reaction speed of enzyme and enzyme reduces.Therefore select suitable reaction temperature, the usefulness of giving full play to zytase is significant.Temperature is to three kinds of Novel xylanase X ₁, X ₂, X ₃The result of study that affects on fast-growing poplar NaOH anthraquinone slurry oxygen delignification effect sees Table 4,5,6.

Table 4 temperature is to zytase X ₁The impact of the oxygen delignification performance of pretreating paper pulp

Annotate: enzyme dosage is 8IU/L, time 120min, starch dense 10%, pH value 8-9.

As can be seen from Table 4, along with the rising of temperature, zytase X ₁The usefulness of performance increases afterwards first and weakens, and when temperature during at 55 ℃, the whiteness of paper pulp reaches 60.1%ISO, reaches maximum, and the Kappa number of paper pulp is down to minimum, and viscosity remains on best level; When temperature surpassed 60 ℃, pulp brightness began to reduce, and the viscosity of paper pulp descends obviously.This shows zytase X ₁Enzyme activity in the time of 55 ℃, be more satisfactory.But consider zytase X from actual production ₁Select treatment temperature be 50-55 ℃ relatively good, the practical operation that is conducive to produce and reduce the adjusting difficulty of temperature is conducive to reduce production costs and increase economic efficiency.

As can be seen from Table 5, along with temperature raises, zytase X ₂The effect of performance increases afterwards first and weakens.As can be seen from Table 5, along with the rising of pretreatment temperature, the pulp brightness behind the oxygen delignification begins to improve, but when temperature surpassed 55 ℃, the whiteness of paper pulp began to reduce behind the oxygen delignification; When temperature was lower than 55 ℃, the Kappa number of paper pulp reduced along with the rising of temperature, but when temperature surpasses 55 ℃, and the rising that Kappa number begins no longer to reduce on the contrary with temperature raises; When temperature during at 55 ℃-60 ℃, the viscosity of paper pulp becomes along with the rising of temperature greatly, but when temperature surpassed 60 ℃, the viscosity decrease speed was obvious.These experimental results show zytase X ₂The usefulness of preliminary treatment fast-growing poplar sulfate pulp performance is maximum when temperature is 55-60 ℃.

Table 5 temperature is to zytase X ₂The impact of the oxygen delignification performance of pretreating paper pulp

Annotate: enzyme dosage is 6IU/g, time 120min, starch dense 10%, pH value 8-9.

As can be seen from Table 6, as zytase X ₃When being 50 ℃ with the temperature of paper pulp effect, the pulp brightness behind the oxygen delignification is the highest, reaches 60%ISO, and it is minimum 7.2 that the Kappa number of paper pulp reaches, and the viscosity of paper pulp reaches maximum 731mL/g.Also can find out from table 6, along with the further rising of temperature, the whiteness of paper pulp begins to reduce behind the oxygen delignification, and Kappa number begins to raise, and the viscosity of paper pulp descends.This shows, zytase X ₃Performance helps that to float effect best when temperature is 50 ℃.

Table 6 temperature is to zytase X ₃The impact of the oxygen delignification performance of pretreating paper pulp

Annotate: enzyme dosage is 8IU/g, time 120min, starch dense 10%, pH value 8-9.

Can find out from table 4,5,6, the character of paper pulp is better behind the oxygen delignification of the temperature of three kinds of zytases preliminary treatment fast-growing poplar sulfate pulp when 50-60 ℃ of scope.Zytase X ₁The usefulness of enzyme is better when temperature is 50-55 ℃, zytase X ₂The efficient of enzyme is comparatively desirable when temperature is 55-60 ℃, zytase X ₃Enzyme is most effective when temperature is 50 ℃.When respectively three kinds of zytases being carried out zymologic property research, as substrate, the optimum temperature of three kinds of zytases is 55-60 ℃ with pure xylan, but in the actual experiment, zytase X ₁And X ₃During pretreating paper pulp, when reaching optimum efficiency, decrease than ideal temperature, this may with paper pulp in xylan and the structure of pure xylan or character there are differences and cause.But zytase X ₂The optimal temperature of pretreating paper pulp is consistent with the temperature of zymologic property research, and this may be relevant with the characteristic of enzyme self.

1.3pH value is on the impact of fast-growing poplar sulfate pulp oxygen delignification

The scope of application difference of different zytase pH is also very large, and the pH value that they are fit to can be divided into acidity, neutrality and alkaline.The activity of most of zytase need to competence exertion effect in the pH value scope that is fit to, and pH value is crossed to exceed to hang down all can affect the conformation of zymoprotein, even zytase is lost activity, thereby directly has influence on the effect of xylanase treatment paper pulp.The zytase of the paper pulp after the most suitable processing boiling is alkaline enzyme, the present invention first three kinds of enzymes that Novel xylanase all is meta-alkalescence of usefulness.Different pH values see Table 7,8,9 to the experimental data of these three kinds of xylanase treatment fast-growing poplar sulfate pulp oxygen delignification effects.

Table 7pH value is to zytase X ₁Pretreating paper pulp is on the impact of oxygen delignification effect

Annotate: enzyme dosage is 8IU/L, temperature 50 C, and time 120min starches dense 10%.

As can be seen from Table 7, zytase X ₁The whiteness of paper pulp is along with the increase of pH value increases first rear reduction behind the preliminary treatment fast-growing poplar sulfate pulp oxygen delignification, and when pH value 8, the whiteness of paper pulp is up to 60.1%ISO; The Kappa number of paper pulp is along with the increase of pH value reduces first rear increase, when pH value 8, and Kappa number minimum 7.1; The viscosity of paper pulp is along with the increase of pH value increases first rear reduction, and when pH value 8, the viscosity of paper pulp reaches maximum 740mL/g.As can be seen from Table 7, the pH value when 9-10, zytase X ₁Usefulness also good, kept higher whiteness, lower Kappa number and higher viscosity.Consider from the angle of actual production, using zytase X ₁The time pH value the best be modulated to 8, if but be modulated at the scope of 8-10, also can bring into play better and more stable effect and usefulness.

As can be seen from Table 8, zytase X ₂The whiteness of paper pulp is along with the increase of pH value increases first rear reduction behind the preliminary treatment fast-growing poplar sulfate pulp oxygen delignification, and when pH value 8, the whiteness of paper pulp is up to 60.2%ISO; The Kappa number of paper pulp is along with the increase of pH value reduces first rear increase, when pH value 9, and Kappa number minimum 7.2; The viscosity of paper pulp is along with the increase of pH value increases first rear reduction, and when pH value 9, the viscosity of paper pulp reaches maximum 740mL/g.This shows zytase X ₂Effect when the pH value is 8-9 is best, has kept the highest whiteness of paper pulp, minimum Kappa number and maximum viscosity.The pH value be 7 and 10 o'clock pretreating effect when being 8-9 than the pH value effect slightly poor, but from the angle of actual production, zytase X ₂The pH value that is fit to be that alkalescent or neutrality are fine, but best pH value is in the scope of 8-9.

Table 8pH value is to zytase X ₂Pretreating paper pulp is on the impact of oxygen delignification effect

Annotate: enzyme dosage is 6IU/g, 55 ℃ of temperature, and time 120min starches dense 10%.

As can be seen from Table 9, zytase X ₃The whiteness of paper pulp is along with the increase of pH value increases first rear reduction behind the preliminary treatment fast-growing poplar sulfate pulp oxygen delignification, and when pH value 8, the whiteness of paper pulp is up to 60.2%ISO; The Kappa number of paper pulp is along with the increase of pH value reduces first rear increase, when pH value 8, and Kappa number minimum 7.1; The viscosity of paper pulp is along with the increase of pH value increases first rear reduction, and when pH value 8, the viscosity of paper pulp reaches maximum 734mL/g.When pH value 9, the whiteness 60%ISO of paper pulp, Kappa number 7.2, the viscosity 731 of paper pulp, effect gap a little during with pH value 8, but gap is very little, can draw thus, zytase X ₁The better pH value of pretreating paper pulp is 8-9.

Table 9pH value is to zytase X ₃Pretreating paper pulp is on the impact of oxygen delignification effect

Annotate: enzyme dosage is 8IU/g, temperature 50 C, and time 120min starches dense 10%.

Can find out from table 7,8,9, the pH value of three kinds of zytases treatment effect to paper pulp in the 8-10 scope is all more satisfactory.Zytase X ₁Best pH value is 8, zytase X ₂Optimal pH be 8-9, zytase X ₃Optimal pH be 8.When respectively three kinds of zytases being carried out zymologic property research, as substrate, the optimum pH value of three kinds of zytases all is 8, zytase X for the treatment of paper pulp the time with pure xylan ₁And X ₃Only pH value all is 8, and the zymologic property of this and they matches.And zytase X ₂The optimum value of pulp treatment is 8 and 9, and is not quite identical with its zymologic property, and alkali resistance increases when pulp treatment, can reduce like this number of times of pulp washing after the boiling, and saving water resource and reduce energy consumption is conducive to the application of actual production.

1.4 the time is on the impact of fast-growing poplar sulfate pulp oxygen delignification effect

There is certain influence time to xylanase treatment fast-growing poplar sulfate pulp, if the time is too short, then the performance of enzyme can't be performed to ultimate attainment, if overlong time is unfavorable for enhancing productivity.Based on this, in immobilized enzyme consumption, temperature, pH value with starch and studied the impact of time on the pretreatment effect under the dense condition.Experimental result sees Table 10,11,12.

Table 10 time is to zytase X ₁Pretreating paper pulp is on the impact of oxygen delignification effect

Annotate: enzyme dosage is 8IU/L, temperature 50 C, and pH value 8-9 starches dense 10%.

As can be seen from Table 10, along with the prolongation of time, zytase X ₁Fast-growing poplar sulfate pulp after the processing begins after the whiteness of paper pulp progressively improves to reduce behind oxygen delignification, and when the time was 120min, the whiteness of paper pulp reached peak 60.1%ISO; The Kappa number of paper pulp begins to raise after progressively reducing first, when time during at 120min, and Kappa number near minimum 7.1; Begin after the viscosity of paper pulp progressively raises to reduce, when the time was 120min, the viscosity of paper pulp reached maximum 740mL/g.Also can find out from the experimental data of table 10, along with the prolongation of time, the action effect of enzyme begins to descend, and this may be because zytase and paper pulp be long action time, and enzymolysis product has produced certain inhibitory action to the reaction of enzyme and paper pulp.So zytase X ₁The time 120min of pulp treatment is advisable.

As can be seen from Table 11, along with the prolongation of time, zytase X ₂Fast-growing poplar sulfate pulp after the processing is behind oxygen delignification, and the whiteness of paper pulp also is the rear reduction that raises first, and when the time was 120min, the whiteness of paper pulp was up to 60.2%ISO; The Kappa number of paper pulp descends first and begins afterwards to uprise, and when the time reached 120min, the Kappa number of paper pulp was minimum to 7.2; The viscosity of paper pulp begins to reduce after becoming first greatly, and when the time was 120min, the viscosity of paper pulp was up to 745mL/g.The experimental data of consolidated statement 11 can draw, zytase X ₂The time of pulp treatment is not that the longer the better, and after the time surpassed 120min, the action effect of enzyme began to weaken, so zytase X ₃The time 120min of pulp treatment is advisable.

Table 11 time is to zytase X ₂Pretreating paper pulp is on the impact of oxygen delignification effect

Annotate: enzyme dosage is 6IU/g, 55 ℃ of temperature, and pH value 8-9 starches dense 10%.

As can be seen from Table 12, along with the prolongation of time, zytase X ₃Fast-growing poplar sulfate pulp after the processing behind oxygen delignification, the rear reduction that raises first of the viscosity of paper pulp, when the processing time was 120min, the viscosity of paper pulp reached maximum 731mL/g; The whiteness of paper pulp also is the rear reduction that raises first, and when the processing time was 120min, the whiteness of paper pulp also was to improve first rear reduction, and when the processing time was 120min, the whiteness of paper pulp reached maximum 60%ISO; It is large that the Kappa number of paper pulp reduces first rear change, and when the processing time was 120min, the Kappa number of paper pulp was down to minimum 7.2.Also can find out from table 12, when reaching the highest whiteness, minimum Kappa number and the highest viscosity, zytase X ₃The pulp treatment time is 120min, surpasses this time treatment effect and just begins to weaken, and this may be because zytase and paper pulp be long action time, and enzymolysis product has produced certain inhibitory action to the reaction of enzyme and paper pulp.

Table 12 time is to zytase X ₃Pretreating paper pulp is on the impact of oxygen delignification effect

Annotate: enzyme dosage is 8IU/g, temperature 50 C, and pH value 8-9 starches dense 10%.

Can find out that from table 10,11,12 these three kinds of zytases are basically identical to the treatment effect of paper pulp: the one, along with the prolongation of time, the rear reduction that raises first of the whiteness of paper pulp, the Kappa number of paper pulp reduces first rear rising, and the viscosity of paper pulp increases afterwards first and diminishes; The 2nd, the time of continuing these three kinds of xylanase treatment paper pulp of prolongation, the whiteness of paper pulp begins to reduce, Kappa number begins to raise, pulp viscosity begins to descend.Be advisable when therefore the optimization process time all is controlled at 120min.Table 10,11,12 experimental result also show, be not that the longer the better action time for zytase and paper pulp, but there is a better time, if overlong time, may affect the activity of enzyme, also may make the part lignin of stripping begin again to deposit on the fiber, reduce the usefulness of zytase, overlong time also is unfavorable for enhancing productivity simultaneously.Therefore it is very important selecting the time of suitable xylanase treatment paper pulp.

Comprehensive above-mentioned experimental technique analysis result can draw the process conditions of the better processing fast-growing poplar sulfate pulp of three kinds of zytases: zytase X ₁The preferred process condition be: enzyme dosage 8IU/L, temperature 50 C, pH8, time 120min; Zytase X ₂The preferred process condition be: enzyme dosage 6IU/g, 55 ℃ of temperature, pH8-9, time 120min; Zytase X ₃The preferred process condition be: enzyme dosage 8IU/g, temperature 50 C, pH8-9, time 120min.

The optimization of embodiment 2 bleaching conditions

2.1.1 raw material

Experiment is to mix the quick growth poplar wood sheet with the quick growth poplar wood sheet, takes from Shandong sun Paper Co., Ltd.Chip dimensions length 15-25mm, width 10-20mm, thickness 3-5mm, the qualification rate of wood chip is more than 90%, and is after wood chip is fetched from the stock ground, for subsequent use behind the natural air drying equilibrium water conten.

Zytase X ₁Provided by Novozymes Company, liquid, the cellulose-less enzyme is lived; Zytase X ₂, X ₃All have Shenzhen biological Co., Ltd of green little health to provide, be the white powder solid, all cellulase is not lived.

2.1.2 boiling experiment

In 15L electric heating rotating autoclave, carry out boiling, make fast-growing poplar sulfate magma.The condition of boiling is: alkali charge 20%(is to over dry raw material, Na ₂The O meter), sulphidity 24%, liquor ratio 1:4,165 ℃ of boiling maximum temperatures are carried out little venting 15min, heating-up time 120min, temperature retention time 90min in the time of 105 ℃.The boiling disposed slurry is through fully washing, screening.Paper pulp yield 49.6%, the Kappa number 18.9 of paper pulp, viscosity 950ml/g, whiteness 36.5%ISO.

2.1.3 xylanase pretr eatment

Three kinds of xylanase pretr eatment experiments are all finished in polyethylene plastic bag.Poplar sulfate pulp and the enzyme good washing after the boiling mix in plastic bag, enzyme treatment process condition and experimental procedure according to embodiment 1 optimization, regulate the pH value and starch zytase liquid that dense rear handle modulates put into bag and evenly mix after, put into the water-bath that sets temperature and carry out constant temperature and process.In processing procedure, every interval 10-15min rubs once with hand, to guarantee that enzyme mixes with the even of paper pulp.Slurry takes out after processing the stipulated time, then puts into boiling water bath 10min, makes zytase inactivation cessation reaction, with entering the following bleaching operation behind the running water cleaning paper pulp.

2.1.4 oxygen delignification and the experiment of reinforcement oxygen delignification

The experiment of fast-growing poplar sulfate pulp oxygen delignification is carried out in JF-DSTE polymerization reaction kettle (have and stir and the automatic constant-temperature function).Its Oxygen Delignification of Fast-Growing is: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 80min, MgSO ₄All drug dosages of consumption 0.5%(are all for oven dry stock, and are as follows).

The process conditions of two sections oxygen delignifications: first paragraph O ₁: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 20min, MgSO ₄Consumption 0.5%; Second segment O ₂: replenish 0.5% NaOH, oxygen is pressed 0.5MPa, time 60min.

Fast-growing poplar sulfate pulp is strengthened oxygen delignification O _pProcess conditions be: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, MgSO ₄Consumption 0.5%, Na ₂SiO ₃Consumption 0.7%, H ₂O ₂Consumption 3%, time 80min.

First paragraph oxygen delignification and second segment are strengthened the process conditions of oxygen delignification: first paragraph O ₁: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 20min, MgSO ₄Consumption 0.5%; Second segment O _2P: replenish 0.5% NaOH, add 3% H ₂O ₂, Na ₂SiO ₃Consumption 0.7%, oxygen is pressed 0.5MPa, time 60min.

Two sections process conditions of strengthening oxygen delignification: first paragraph O _1P: starch dense 10%, NaOH consumption 2.5%, H ₂O ₂Consumption 1%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 20min, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%; Second segment O _2P: replenish 0.5% NaOH, add 2.5% H ₂O ₂, oxygen is pressed 0.5MPa, time 60min.

2.1.5 the bleaching experiment of paper pulp

The bleachings such as D, E, Q, P or processing section carry out in polyethylene plastic bag respectively.Get the 30g oven dry stock at every turn, according to the experimental procedure of drafting, pour in the plastic bag after required liquid evenly mixed, put into thermostat water bath after slurry and liquid are mixed and bleach or process.In the process of bleaching or processing, every interval 15min takes out and rubs even mixing once with hand, guarantees paper pulp and the even mixing of floating agent.

2.1.6 analytical method

The mensuration of viscosity: the method according to standard GB/T 1548-1989 regulations is carried out.

The mensuration of Kappa number: according to GB1546-1989 standard test.

The mensuration of whiteness: paper pulp is discongested after device discongests through fiber, copies into the scraps of paper at Buchner funnel, air-dry measure with YQ-Z-48B whiteness instrument afterwards.

Folding number: domestic MIT folding strength tester is measured in using.

Burst index: use swedish company L﹠amp; The bursting strength tester that W produces is measured.

Fracture length: use swedish company L﹠amp; The anti-tester that W produces is measured.

Tear index: measure with the tearability tester that the TMI of u s company produces.

2.1.7 the mensuration of making beating and beating energy consumption

Slurry behind the defibrination adopts KRK company to produce the PFI mill and pulls an oar, and beating consistency is 10%, and beater roll(er) and beater chamber gap are 0.2mm, and beating pressure is 3.4Nmm ^-1The beating degree of making beating disposed slurry is measured and is adopted Xiao Baier-Rui Gele YQ-Z-13 beating degree analyzer to measure.

The revolution of making beating specific energy consumption: PFI mill is linear with beating energy consumption within the specific limits, and this experiment required making beating revolution when reaching identical beating degree calculates the energy loss-rate.Bleached pulp making beating revolution * 100% of the beating energy consumption reduction rate in this experiment=(enzyme is processed the bleached pulp making beating revolution of after bleaching slurry making beating revolution-do not process with enzyme)/do not process with enzyme.

2.1.8 ESEM

To under the identical experiment condition of embodiment 1 " oxygen delignification experiment ", carry out respectively oxygen-delignified pulp from magma through the paper pulp that different enzymes are processed, carry out the different orders of floating subsequently and bleach gained paper pulp etc., after the running water washing, utilizing the quick handshcet former of triumphant match to copy the formulation amount is 60g/m ²The l Water Paper page or leaf then with l Water Paper page or leaf in vacuum drier dry 48 hours, after metal spraying is processed, is that the ESEM of QUANTA200 is observed and taken pictures in model, and accelerating potential is 10kV.

2.1.9 atomic force microscope observation

Getting slurry sample 0.1g to be measured is distributed in the distilled water of 200mL, break up with dispersing device, fiber is evenly distributed in the water, then getting a droplet with pipette is put on the mica sheet, so that single fiber is distributed on the mica sheet, then air-dry 24h under the room temperature uses MultiMode SPM model AFM (AFM) produced in USA to carry out scanning and photograph, and the model of probe is NP-20.

2.1.10 xylanase activity is measured

Adopt the DNS method to measure (being conventional determining method of the prior art).

2.1.11 enzyme preparation characteristic is determined

Zytase X ₁, X ₂, X ₃Enzyme activity determination measure according to the DNS method, it the results are shown in Table 13 and table 14.

The characteristic of table 13 liquid xylanase preparation

The characteristic of table 14 solid xylanase preparation

2.2 result and discussion

2.2.1 xylanase treatment is to the effect of fast-growing poplar sulfate pulp ECF bleaching

Zytase is used for the preliminary treatment before the association with pulp bleaching, has the consumption that reduces chlorine-containing bleaching, further alleviates the pollution to environment, improve filterability and the fragility of paper pulp, increase fiber separating degree, improve the whiteness of floating rear paper pulp, reduce beating energy consumption, the advantage such as save production cost.The fast-growing poplar is the important paper making raw material of northern China, and it has higher whiteness, long fibre length and material density is moderate, and easily the easy characteristics of bleaching of boiling are fit to the high whiteness of preparation and high-intensity chemical pulp.For this reason, the present invention carries out bleaching research to the fast-growing poplar sulfate pulp that three kinds of Novel wooden glycan are used for different bleaching process, inquire into the whiteness of Xylanase-aided Bleaching paper pulp, the fibre morphology variation etc. that becomes the physical strength index of paper and float rear slurry, for novel commercial xylanase provides theoretical foundation in fast-growing poplar kraft bleaching industrial applications and popularization.

The present embodiment contains all bleaching process of oxygen delignification section bleaching, all carries out before oxygen delignification during xylanase treatment paper pulp, and its process conditions are the xylanase treatment process conditions of optimizing among the embodiment 1.

2.2.1.1 three kinds of xylanase pretr eatments are on the impact of fast-growing poplar sulfate pulp ODQP bleaching results

Adopt zytase X ₁, X ₂And X ₃Before fast-growing poplar sulfate pulp ODQP floats the order bleaching, carry out preliminary treatment, inquire into xylanase treatment to the impact of fast-growing poplar kraft bleaching performance.

The process conditions of three kinds of xylanase treatment fast-growing poplar sulfate pulp oxygen delignification best results optimizing according to embodiment 1 carry out this experiments in conjunction with the ODQP bleaching conditions.Concrete process conditions are as follows: X ₁The process conditions of processing: enzyme dosage 8IU/L, temperature 50-55 ℃, pH8, time 120min; X ₂The process conditions of processing: enzyme dosage 6IU/g, temperature 55-60 ℃, pH8-9, time 120min; X ₃The process conditions of processing: enzyme dosage 8IU/g, temperature 50 C, pH8-9, time 120min.

ODQP floats the process conditions of order bleaching: the process conditions of oxygen delignification section are seen 2.1.4.D section: ClO ₂Consumption is 0.7%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA consumption 0.5%, temperature 70 C, time 60min, pH value 4-5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

Through and do not carry out simultaneously the ODQP bleaching through the poplar sulfate pulp of xylanase treatment, to guarantee the comparativity of bleaching results, xylanase pretr eatment sees Table 15 to fast-growing poplar sulfate pulp ODQP bleaching results.Paper pulp after the bleaching is pulled an oar with the PFI mill, and the making beating revolution of controlling various slurries is controlled at about 41 ° of SR its beating degree, then copies and makes quantitative 60g/m ²Paper, then the physical properties such as its folding strength, bursting strength, tear index, fracture length are detected its result such as table 16.

Table 15 xylanase pretr eatment is on the impact of fast-growing poplar sulfate pulp ODQP bleaching results

As can be seen from Table 15, fast-growing poplar sulfate pulp is floated bleaching results that order finishes through XODQP and is better than ODQP and floats order.X wherein ₂The final bleaching whiteness that ODQP floats order is the highest, reaches 87.0%, and the final whiteness of floating order than ODQP exceeds 2.5%ISO, and floats the pulp viscosity 791mLg that has kept the highest in the order at these four kinds ^-1Next is X ₁The bleaching results that ODQP floats order is comparatively desirable, and the final whiteness of paper pulp reaches 86.7%ISO, and the final whiteness of floating order than ODQP exceeds 2.2%ISO, and has kept higher pulp viscosity 786mLg ^-1That the enzyme action effect is relatively weak is X ₃ODQP floats order, but the final whiteness of floating rear slurry has also reached 86.5%ISO, and the final whiteness that the ODQP that does not more process with enzyme floats order exceeds 2.0%ISO, and the viscosity of paper pulp also exceeds 12mLg than the viscosity of the paper pulp of not processing with enzyme ^-1

As can be seen from Table 15, through xylanase treatment and do not pass through the paper pulp of xylanase treatment, float the order bleaching through ODQP after, the final Kappa number of paper pulp is also different, X ₂It is minimum 2.1 that ODQP floats the Kappa number of order, floats low 0.5 unit of Kappa number of order than ODQP, secondly is X ₁The Kappa number that ODQP floats order is 2.2, floats low 0.4 unit of Kappa number of order than ODQP, is X at last ₃The Kappa number that ODQP floats order is 2.3, floats low 0.3 unit of Kappa number of order than ODQP.These show, paper pulp through enzyme is processed floats in the order bleaching process at ODQP, more is conducive to removing of lignin, further reduce the Kappa number of paper pulp, and kept than the conventional higher pulp viscosity of order bleaching that floats, this may be that cellulase is alive because of three kinds of zytases, and the effect of zytase is so that paper pulp fiber shows the degraded of part hemicellulose, liquid impregnate property is better, remove more lignin, reduced the Kappa number that floats rear slurry, improved the whiteness of floating rear paper pulp.

Also can find out from table 15, after paper pulp process ODQP and the XODQP bleaching, copy the quantitative 60g/m of being that makes through making beating ²Paper, the whiteness of paper has decline in various degree.Wherein, it is at most 2.1%ISO that the whiteness of floating order through the ODQP of xylanase treatment reduces, the X that processes through enzyme ₂The whiteness reduction minimum that ODQP floats order is 1.8%ISO, through X ₁ODQP and X ₃The loss of whiteness that ODQP floats order is 1.9%ISO, these show through the loss of whiteness of the paper pulp of three kinds of xylanase treatments paper pulp after making beating still less, this may be because the Kappa number of slurry is lower after the floating after processing through enzyme, lignin content still less, paper pulp is difficult for brightness reversion.

As can be seen from Table 16, the pulp beating after the paper pulp after the XODQP bleaching is bleached than ODQP is easier.When reaching close 41 ° of SR of beating degree, required making beating revolution still less, the beating energy consumption reduction rate is greatly about about 20%, this may be because the processing of paper pulp process zytase, sub-fraction hemicellulose degraded in the paper pulp, the bleaching liquid more easily is impregnated in the gap of cellulose and hemicellulose, when impelling more lignin strippings, so that fiber softening makes making beating easier to be more energy-conservation.

The comparison of table 16ODQP/XODQP bleached pulp physical properties of paper

The physical indexs such as the folding strength of the paper pulp after as can be seen from Table 16, the paper pulp after the XODQP bleaching is bleached than ODQP, bursting strength, fracture length are better.The bleached pulp that XODQP and ODQP float order is all copied and made quantitatively is 60g/m ²Paper, through X ₂Physical property of pulp after the ODQP bleaching is best, and with exceeding 55 times that enzyme is processed, fracture length has not improved 0.34Km to the folding strength ratio, and burst index exceeds 0.6Nmg ^-1, several slurry tear indexes are very approaching, but X ₂It also is that this severally floats rear slurry and copy the peak of making paper that ODQP floats rear slurry.Through X ₁ODQP and X ₃ODQP floats the rear slurry of floating of order, has shown equally good physical property: these two kinds of bleached pulps are copied the paper folding strength made than the ODQP bleached pulp and are improved 40 times, and fracture length improves respectively 0.29 and 0.3Km.But through X ₁ODQP and X ₃ODQP floats rear slurry than the tear index decline 0.14 and the 0.18mNm that float rear slurry of ODQP ²G ^-1, this may be because the bleaching liquid soaks into more fully, to fiber also to some extent damage, also may be that the reason such as the slightly different or error of beating degree causes when removing more lignins.

In sum, after floating order bleaching through XODQP, can improve the final whiteness 2.1-2.5%ISO of paper pulp, XODQP floats rear slurry and floats rear slurry than ODQP and kept higher pulp viscosity, also keep better bleaching selectivity, improved more significantly the physical property of floating rear slurry.

2.2.1.2 three kinds of xylanase pretr eatments are to fast-growing poplar sulfate pulp O _PThe impact of DQP bleaching results

Adopt zytase X ₁, X ₂And X ₃At fast-growing poplar sulfate pulp O _PDQP carries out preliminary treatment before floating the order bleaching, inquires into xylanase treatment to fast-growing poplar sulfate pulp O _PDQP floats the impact of order bleachability.

The process conditions of three kinds of xylanase treatment fast-growing poplar sulfate pulp oxygen delignification best results optimizing according to embodiment 1 are in conjunction with O _PThe DQP bleaching conditions carry out this experiment.Concrete process conditions are as follows: X ₁The process conditions of processing: enzyme dosage 8IU/L, temperature 50-55 ℃, pH8, time 120min; X ₂The process conditions of processing: enzyme dosage 6IU/g, temperature 55-60 ℃, pH8-9, time 120min; X ₃The process conditions of processing: enzyme dosage 8IU/g, temperature 50 C, pH8-9, time 120min.

O _PDQP floats the process conditions of order bleaching: the process conditions of strengthening the oxygen delignification section are seen 2.1.4.D section: ClO ₂Consumption is 0.5%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA consumption 0.5%, temperature 70 C, time 60min, pH value 4-5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

Pass through and do not pass through the poplar sulfate pulp of xylanase treatment and carry out simultaneously O _PThe DQP bleaching, to guarantee the comparativity of bleaching results, xylanase pretr eatment is to fast-growing poplar sulfate pulp O _PThe DQP bleaching results sees Table 17.Paper pulp after the bleaching is pulled an oar with the PFI mill, and the making beating revolution of controlling various slurries is controlled at about 45 ° of SR its beating degree, then copies and makes quantitative 60g/m ²Paper, then the physical properties such as its folding strength, bursting strength, tear index, fracture length are detected its result such as table 18.

Table 17 xylanase pretr eatment is to fast-growing poplar sulfate pulp O _PThe impact of DQP bleaching results

As can be seen from Table 17, fast-growing poplar sulfate pulp is through XO _PDQP floats the bleaching results that order finishes and is better than O _PDQP floats order.X wherein ₂O _PThe final bleaching whiteness that DQP floats order is the highest, reaches 89.7%ISO, than O _PThe final whiteness that DQP floats order exceeds 2.5%ISO, and is these four kinds of maximum 760mLg that float pulp viscosity in the order ^-1Next is X ₁O _PIt is better that DQP floats the bleaching results of order, and the final whiteness of paper pulp reaches 89.3%ISO, than O _PThe final whiteness that DQP floats order exceeds 2.1%ISO, and has kept higher pulp viscosity 759mLg ^-1X ₃O _PDQP floats order and floats the final whiteness of rear slurry and reached 89.3%ISO, the O that does not more process with enzyme _PThe final whiteness that DQP floats order exceeds 2.1%ISO, and the viscosity of paper pulp also exceeds 11mLg than the viscosity of the paper pulp of not processing with enzyme ^-1

As can be seen from Table 17, through paper pulp xylanase treatment and that do not pass through xylanase treatment, at process O _PAfter DQP floated order bleaching, the final Kappa number of paper pulp was also different, X ₂O _PIt is minimum 1.3 that DQP floats the Kappa number of order, than O _PDQP floats low 0.5 unit of Kappa number of order, secondly is X ₁O _PThe Kappa number that DQP floats order is 1.4, than O _PDQP floats low 0.4 unit of Kappa number of order, is X at last ₃O _PThe Kappa number that DQP floats order is 1.5, than O _PDQP floats low 0.3 unit of Kappa number of order.These experimental datas show, through the paper pulp of enzyme processing, at O _PDQP floats in the order bleaching process, more be conducive to removing of lignin, further reduce the Kappa number of paper pulp, improve the whiteness of paper pulp, kept than the conventional higher pulp viscosity of order bleaching that floats, this may be that cellulase is alive because of three kinds of zytases, the effect of zytase is so that paper pulp fiber shows the degraded of part hemicellulose, and liquid impregnate property is better, has removed more lignin, reduce the Kappa number that floats rear slurry, improved the whiteness of floating rear paper pulp.

Also can find out from table 17, paper pulp is through O _PDQP and XO _PAfter the DQP bleaching, copy the quantitative 60g/m of being that makes through making beating ²Paper, the whiteness of paper has decline in various degree.Wherein, do not pass through the O of xylanase treatment _PThe whiteness reduction that DQP floats order is at most 2.0%ISO, through the X of enzyme processing ₂O _PDQP, X ₁O _PDQP and X ₃O _PThe whiteness reduction value that DQP floats order all is 1.7%ISO, these show through the loss of whiteness of the paper pulp of three kinds of xylanase treatments paper pulp after making beating still less, this may be because the Kappa number of slurry is lower after the floating after processing through enzyme, lignin content still less, paper pulp more is difficult for brightness reversion.

Can find out from table 15 and 17, through XO _PDQP and XODQP, O _PDQP and ODQP float the paper pulp of order bleaching, and the former whiteness is higher, and the loss of viscosity is larger; Generally speaking, it is relatively more difficult that the whiteness of paper pulp reaches 88%ISO, but through XO _PDQP floats the bleaching of order, has all reached more than the 89.3%ISO, and these experimental datas show that the preliminary treatment of zytase helps to solve the practical difficulty that the final whiteness of paper pulp is difficult to raising, and this will be conducive to the application of zytase in actual production.

Can find out XO from 18 _PPaper pulp after the DQP bleaching compares O _PPulp beating after the DQP bleaching is easier.When reaching close 45.5 ° of SR of beating degree, required making beating revolution few 3000 turns, save beating energy consumption about 20%, this may be because the processing of paper pulp process zytase, sub-fraction hemicellulose degraded in the paper pulp, the bleaching liquid more easily is impregnated in the gap of cellulose and hemicellulose, when impelling more lignin strippings, so that fiber softening makes making beating easier to be more energy-conservation.Comparison sheet 16 and 18 can be found out XO _PDQP and XODQP, O _PDQP and ODQP float rear slurry making beating revolution when identical, and the former beating degree is about 45.5 ° of SR, and the latter's beating degree is about 41 ° of SR, and this shows strengthens oxygen delignification O _PWhen improving pulp brightness and further removing lignin reduction paper pulp kappa number, fiber also has been subject to larger damage than O section, so that fiber average degree of polymerization or length shorten more easily making beating.

Table 18O _PDQP/XO _PThe comparison of DQP bleached pulp physical properties of paper

As can be seen from Table 18, XO _PPaper pulp after the DQP bleaching compares O _PThe physical indexs such as the folding strength of the paper pulp after the DQP bleaching, bursting strength, fracture length are better.XO _PDQP and O _PThe bleached pulp that DQP floats order is all copied and is made quantitative 60g/m ²About paper, through X ₂O _PPhysical property of pulp after the DQP bleaching is best, and with exceeding 50 times that enzyme is processed, fracture length has not improved 0.43Km to the folding strength ratio, and burst index exceeds 0.5Nmg ^-1, several slurry tear indexes are very approaching, but X ₂O _PIt also is that this severally floats rear slurry and copy the maximum 5.77mNm that makes paper that DQP floats rear slurry ²G ^-1Through X ₁O _PDQP and X ₃O _PDQP floats the rear slurry of floating of order, has shown equally good physical property: these two kinds of bleached pulps are than O _PThe DQP bleached pulp is copied the paper folding strength of making and is improved more than 40 time, and fracture length improves respectively 0.33 and 0.35Km.But through X ₁O _PDQP and X ₃O _PDQP floats rear slurry than O _PThe tear index decline 0.05 and the 0.16mNm that float rear slurry of DQP ²G ^-1, this may be because the bleaching liquid soaks into more fully, to fiber also to some extent damage, also may be slightly different causing of beating degree when removing more lignins.That is to say XO _PDQP and O _PThe DQP bleaching may diminish on the paper tear index afterwards but affect little.

In sum, through XO _PAfter DQP floated the order bleaching, the whiteness maximum of paper pulp reached 89.7%ISO, and kept relatively high viscosity, than O _PThe paper pulp of DQP bleaching can improve the final whiteness 2.1-2.5%ISO of paper pulp, XO in the situation that consumes identical chemicals _PDQP floats rear slurry than O _PDQP floats rear slurry and has kept higher pulp viscosity, has also kept better bleaching selectivity, has improved more significantly the physical property of floating rear slurry.

2.2.1.3 three kinds of xylanase pretr eatments are to fast-growing poplar sulfate pulp O ₁O _2PThe impact of DQP bleaching results

Adopt zytase X ₁, X ₂And X ₃At fast-growing poplar sulfate pulp O ₁O _2PDQP carries out preliminary treatment before floating the order bleaching, inquires into xylanase treatment to fast-growing poplar sulfate pulp O ₁O _2PDQP floats the impact of order bleachability.

The process conditions of three kinds of xylanase treatment fast-growing poplar sulfate pulp oxygen delignification best results optimizing according to embodiment 1 are in conjunction with O _PThe DQP bleaching conditions carry out this experiment.Concrete process conditions are as follows: X ₁The process conditions of processing: enzyme dosage 8IU/L, temperature 50-55 ℃, pH8, time 120min; X ₂The process conditions of processing: enzyme dosage 6IU/g, temperature 55-60 ℃, pH8-9, time 120min; X ₃The process conditions of processing: enzyme dosage 8IU/g, temperature 50 C, pH8-9, time 120min.

O _PDQP floats the process conditions of order bleaching: the process conditions of oxygen delignification and reinforcement oxygen delignification section are seen 2.1.4.D section: ClO ₂Consumption is 0.5%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA consumption 0.5%, temperature 70 C, time 60min, pH value 4-5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

Pass through and do not pass through the poplar sulfate pulp of xylanase treatment and carry out simultaneously O ₁O _2PThe DQP bleaching, to guarantee the comparativity of bleaching results, xylanase pretr eatment is to fast-growing poplar sulfate pulp O ₁O _2PThe DQP bleaching results sees Table 19.Paper pulp after the bleaching is pulled an oar with the PFI mill, and the making beating revolution of controlling various slurries is controlled at about 43 ° of SR its beating degree, then copies and makes quantitative 60g/m ²Paper, then the physical properties such as its folding strength, bursting strength, tear index, fracture length are detected its result such as table 20.

Table 19 xylanase pretr eatment is to fast-growing poplar sulfate pulp O ₁O _2PThe impact of DQP bleaching results

As can be seen from Table 19, fast-growing poplar sulfate pulp is through XO ₁O _2PDQP floats the bleaching results that order finishes and is better than O ₁O _2PDQP floats order.X wherein ₂O ₁O _2PThe final bleaching whiteness that DQP floats order is the highest, reaches 89.6%, than O ₁O _2PThe final whiteness that DQP floats order exceeds 2.5%ISO, and is these four kinds of maximum 782mLg that float pulp viscosity in the order ^-1, than O ₁O _2PThe rear slurry viscosity that floats of DQP exceeds 20mLg ^-1Next is X ₁O ₁O _2PIt is better that DQP floats the bleaching results of order, and the final whiteness of paper pulp reaches 89.3%ISO, than O ₁O _2PThe final whiteness that DQP floats order exceeds 2.2%ISO, and has kept higher pulp viscosity 779mLg ^-1, than O ₁O _2PThe rear slurry viscosity that floats of DQP exceeds 17mLg ^-1X ₃O ₁O _2PDQP floats order and floats the final whiteness of rear slurry and reached 89.2%ISO, the O that does not more process with enzyme ₁O _2PThe final whiteness that DQP floats order exceeds 2.1%ISO, and the viscosity of paper pulp is 776mLg ^-1, than O ₁O _2PThe rear slurry viscosity that floats of DQP exceeds 14mLg ^-1

As can be seen from Table 20, through paper pulp xylanase treatment and that do not pass through xylanase treatment, at process O ₁O _2PAfter DQP floated order bleaching, the final Kappa number of paper pulp was also different, X ₂O ₁O _2PIt is minimum 1.3 that DQP floats the Kappa number of order, than O ₁O _2PDQP floats low 0.5 unit of Kappa number of order, secondly is X ₁O ₁O _2PDQP and X ₃O ₁O _2PThe Kappa number that DQP floats order all is 1.4, than O ₁O _2PDQP floats low 0.4 unit of Kappa number of order.These experimental datas show, through the paper pulp of enzyme processing, at O ₁O _2PDQP floats in the order bleaching process, more is conducive to removing of lignin, further reduces the Kappa number of paper pulp, improves the whiteness of paper pulp, has kept than the conventional higher pulp viscosity of order bleaching that floats.

Also can find out from table 20, paper pulp is through O ₁O _2PDQP and XO ₁O _2PAfter the DQP bleaching, copy the quantitative 60g/m of being that makes through making beating ²Paper, the whiteness of paper has decline in various degree.Wherein, do not pass through the O of xylanase treatment ₁O _2PThe whiteness reduction that DQP floats order is at most 1.9%ISO, through the X of enzyme processing ₂O ₁O _2PThe whiteness reduction value that DQP floats order is 1.6%ISO, X ₁O ₁O _2PDQP and X ₃O ₁O _2PThe whiteness reduction value that DQP floats order all is 1.7%ISO, these show through the loss of whiteness of the paper pulp of three kinds of xylanase treatments paper pulp after making beating still less, this may be because the Kappa number of slurry is lower after the floating after processing through enzyme, lignin content still less, paper pulp more is difficult for brightness reversion.

Contrast table 17 and 19 can be found out, through XO _PDQP and XO ₁O _2PDQP, O _PDQP and XO ₁O _2PDQP floats the paper pulp of order bleaching, and both corresponding whiteness are basic identical, and Kappa number is also very near identical, but the differences in viscosity of paper pulp is apart from relatively large.Through one section oxygen delignification O ₁With one section reinforcement oxygen delignification O _2PPaper pulp strengthen oxygen delignification O through simple one section of the ratio of viscosities after the DQP bleaching _PViscosity after slurry is bleached through DQP exceeds 17-22mLg ^-1So, XO ₁O _2PDQP floats order and is better than XO _PDQP, O ₁O _2PDQP floats order and is better than O _PDQP.In the actual production, if when the intensity of consideration paper pulp and whiteness are taken into account simultaneously, can select XO ₁O _2PDQP floats order.

As can be seen from Table 20, XO ₁O _2PPaper pulp after the DQP bleaching compares O ₁O _2PPulp beating energy consumption after the DQP bleaching is lower.When reaching close 43 ° of SR left and right sides of beating degree, required making beating revolution few 3000 turns, save beating energy consumption about 20%, this may be because of the effect of paper pulp process with zytase, sub-fraction hemicellulose degraded in the paper pulp, the bleaching liquid more easily is impregnated in the gap of cellulose and hemicellulose, when impelling more lignin strippings, so that fiber softening, required beating energy consumption is lower.Comparison sheet 18 and 20 can be found out XO _PDQP and XO ₁O _2PDQP, O _PDQP and O ₁O _2PDQP floats rear slurry making beating revolution when identical, and the former beating degree is about 45.5 ° of SR, and the latter's beating degree is about 43.2 ° of SR, and this shows one section oxygen delignification O ₁With one section reinforcement oxygen delignification O _2PStrengthen oxygen delignification O than one section _PAfter the DQP bleaching identical through postorder, when pulp brightness is identical with Kappa number or close, O ₁O _2PCompare O _PThe damage that the better effects if of oxygen delignification, fiber are subject to is less, and the viscosity of paper pulp is higher, and the fiber average degree of polymerization is larger.

Table 20O ₁O _2PDQP/XO ₁O _2PThe comparison of DQP bleached pulp physical properties of paper

As can be seen from Table 20, XO ₁O _2PPaper pulp after the DQP bleaching compares O ₁O _2PPaper pulp after the DQP bleaching has the physical indexs such as better folding strength, bursting strength, fracture length.XO ₁O _2PDQP and O ₁O _2PThe bleached pulp that DQP floats order is all copied and is made quantitative 60g/m ²About paper, through X ₂O ₁O _2PPhysical property of pulp after the DQP bleaching is best, and with exceeding 54 times that enzyme is processed, fracture length has not improved 0.41Km to the folding strength ratio, and burst index exceeds 0.5Nmg ^-1, several slurry tear indexes are very approaching.Wherein, X ₂O ₁O _2PDQP floats rear slurry, and to copy the tear index maximum of making paper be 5.83mNm ²G ^-1Through X ₁O ₁O _2PThe folding strength of floating rear slurry that DQP floats order is than with exceeding 42 times that enzyme is processed, the brisement 0.36Km that grows up, the large 0.5Nmg of burst index ^-1, tear index is close.Through X ₃O ₁O _2PThe folding strength of floating rear slurry that DQP floats order is than with exceeding 39 times that enzyme is processed, the brisement 0.35Km that grows up, the large 0.5Nmg of burst index ^-1, tear index slightly reduces but amplitude is very little.

The experimental data of comparison sheet 18 and table 20 can be found out, XO ₁O _2PDQP floats rear slurry and compares XO _PDQP floats the one-tenth paper of rear slurry, and O ₁O _2PDQP floats rear slurry and compares O _PIt is all better in the corresponding physical index such as folding strength, bursting strength, fracture length, tear index that DQP floats the one-tenth paper of rear slurry.This further shows two sections oxygen delignification O ₁O _2PBe better than one section and strengthen oxygen delignification O _P, enzyme is processed and to be better than the paper pulp do not processed with enzyme, and after this showed that further enzyme is processed, the bleaching liquid soaked into more abundant, and is when destroying more half fiber and remove more lignin and reduce Kappa number, less to the fiber loss of paper pulp.

(X) ODQP, (X) O relatively _PDQP and (X) O ₁O _2PThree kinds of DQP float order, can find, all float the bleaching results that has X to process in the order, and the correspondence that all is better than processing with X on the physical property of the whiteness of paper pulp, viscosity, one-tenth paper and anti-aging degree is not floated order.Three kinds are floated in the order, and (X) totally applied chlorine of ODQP floats rear pulp brightness and reaches more than the 84.5%ISO 0.7%, and (X) O _PDQP and (X) O ₁O _2PThe totally applied chlorine of DQP is 0.5%, but the whiteness of paper pulp can reach more than the 87%ISO.The fewer pollution to environment of chlorine dosage just still less when paper pulp reaches identical whiteness after floating, utilizes the paper pulp of the processing of zytase, can further reduce the consumption that floats agent, reduces the pollution to environment.

The effect of three kinds of xylanase treatment paper pulp is difference to some extent, from the initial effect that affects oxygen delignification, has influence on the bleaching results that ECF respectively floats order always.Wherein help float effect best be X ₂, secondly be X ₁, be X at last ₃But overall relatively, it is all comparatively desirable that the helping of this three kinds of enzymes floated effect.Because the market price of three kinds of enzymes is different, applicable environment is also different, can be as required in the actual production, and the enzyme that alternative costs are suitable, process conditions and production adapt.

2.2.3 scanning electron microscope analysis

For the variation of fiber exterior appearance after further three kinds of xylanase treatments front and back of understanding and bleaching are finished, observe with the bleached pulp that environmental scanning electronic microscope is processed slurry and correspondence to magma, enzyme.

2.2.3.1ECF bleached pulp scanning electron microscopic observation

Choose KP magma, process X ₁The KP slurry of processing, process X ₂The KP slurry of processing, process X ₃The KP slurry of processing obtains Fig. 1～stereoscan photograph shown in Figure 4 according to the requirement of 2.1.8.

Under 1600 times environmental scanning electronic microscope, Aspen KP is starched, X from Fig. 1,2,3,4 ₁The KP slurry, the X that process ₂The KP slurry and the X that process ₃The electromicroscopic photograph on the KP pulp fibres surface of processing can be found out significantly, does not pass through zytase X ₁, X ₂, X ₃The fiber surface of the KP slurry of processing is smooth, and close structure exists without tiny or microfibre.Fiber surface through the KP of three kinds of xylanase treatments slurry becomes loose, soft, and cavity and slit appear in fiber surface, fiber fines is arranged like free state, and the surface area of fiber increases.

2.2.4 AFM Analysis

Fast-growing poplar KP slurry, XODQP slurry etc. before and after three kinds of xylanase treatments are carried out scanning, the situation of change on single fiber surface in the paper pulp before and after the analysis understanding xylanase treatment under AFM.This is tested and adopts light and handy contact mode to observe the fiber surface situation of change of the bleached pulp of magma, enzyme processing slurry and correspondence.

Choose KP magma, process X ₁And X ₂Process the ODQP bleached pulp and obtain two and three dimensions picture such as the AFM of Fig. 5～10 according to the requirement of 2.1.9.

Find by atomic force microscope observation, in the two dimensional image, magma single fiber surface has or not several more stiff small fine fibres to form, after the paper pulp process bleaching through xylanase treatment, the single fiber surface has or not several soft microfibre groups, and the single fiber surface of process enzyme pulp treatment does not have or not several stiff microfibre groups; In the 3-D view, the concavo-convex degree of the single fiber that enzyme is processed is more obvious than the single fiber of processing without enzyme, and the single fiber surface is more loose, pulp freeness is larger, and micro-flexibility increases, more favourable making beating and reduction energy consumption.These bleaching experiment data with the front are consistent, and these show that further the effect of floating of helping of zytase is significantly, effectively.

2.3 brief summary

2.3.1 xylanase treatment is on the result that affects of fast-growing poplar sulfate pulp ECF bleaching

After bleaching through ECF with the paper pulp of not using xylanase treatment, the former whiteness and viscosity are higher, become the physical property of paper also to make moderate progress, and concrete outcome is as follows:

XODQP floats order at ClO ₂In the situation of total consumption 0.7%, the whiteness of bleached pulp is up to 87.0%ISO, minimum 86.5%ISO; The whiteness of ODQP bleached pulp is 84.5%ISO, through enzyme process than not with enzyme process float after the whiteness of slurry exceed 2.0-2.5%ISO, and kept higher pulp viscosity and lower Kappa number;

XO _PDQP floats order at ClO ₂Total consumption 0.5%, H ₂O ₂In the situation of total consumption 5%, the whiteness of bleached pulp is up to 89.7%ISO, minimum 89.3%ISO; O _PThe whiteness of DQP bleached pulp is 87.2%ISO, through enzyme process than not with enzyme process float after the whiteness of slurry exceed 2.1-2.5%ISO, and kept higher pulp viscosity and lower Kappa number; This floats the ClO of order ₂Consumption further reduces, and more meets environmental requirement.

XO ₁O _2PDQP floats order at ClO ₂Total consumption 0.5%, H ₂O ₂In the situation of total consumption 5%, the whiteness of bleached pulp is up to 89.6%ISO, minimum 89.2%ISO; O ₁O _2PThe whiteness of DQP bleached pulp is 87.1%ISO, through enzyme process than not with enzyme process float after the whiteness of slurry exceed 2.1-2.5%ISO, and kept higher pulp viscosity and lower Kappa number; This floats the ClO of order ₂Consumption further reduces, and more is conducive to environmental protection.

Top XODQP and ODQP, XO _PDQP and O _PDQP, XO ₁O _2PDQP and O ₁O _2PThe ECF bleached pulp of DQP is copied through making beating and is made 60g/m ²Paper, the former making beating loss of whiteness value is than the latter still less; The former folding strength on average exceeds 40 times than the latter, and burst index on average exceeds 0.45Nmg ^-1, fracture length on average exceeds 0.35KM, and it is very little that tear index differs.

Relatively the correspondence of three kinds of xylanase treatment paper pulp is floated the bleaching effect discovery of order: the effect of the pulp treatment of three kinds of enzymes is difference to some extent, from the initial effect that affects oxygen delignification, has influence on the bleaching results that ECF respectively floats order always.Wherein help float effect best be X ₂, secondly be X ₁, be X at last ₃But on the whole, these three kinds of enzymes helps that to float effect all apparent in view.When reaching identical or close beating degree, the former required making beating revolution still less can be saved beating energy consumption about 20%.

2.3.2 ESEM result

Under the environmental scanning electronic microscope of 1600 times and 3000 times, can be clearly seen that: the fiber surface through the KP slurry of xylanase treatment is smoothless, and close structure is without tiny or microfibre existence.The fiber of processing the KP slurry through xylan shows and becomes loose, soft, and cavity and slit appear in fiber surface, fiber fines are arranged like free state, and the surface area of fiber increases.

The Aspen KP slurry attenuates than magma to some extent through ECF bleaching, xylanase treatment and untreated KP paper pulp fiber, curling phenomenon occurs.After the KP slurry bleaching of processing through enzyme, the pulp freeness of paper pulp is larger, and fiber surface is more loose, coarse and mixed and disorderly, and it is more soft that fiber becomes, and this can explain to a certain extent through the bleached pulp of enzyme processing and more easily pull an oar, more energy efficient.

2.3.3 atomic force microscope observation result

Observe under AFM, in the two dimensional image, several more stiff microfibres that have or not on magma single fiber surface form; Through the enzyme processing with after bleaching with the magma of enzyme processing, it is more soft and very thin that the single fiber surface becomes, in the 3-D view, the concavo-convex degree of the single fiber that enzyme is processed is more obvious than the single fiber of processing without enzyme, single fiber surface, surface is more loose, pulp freeness is larger, and more favourable making beating is energy-conservation.

Claims (7)

1. the sulfate pulp biochemical process ECF bleaching process of a fast-growing poplar, it is characterized in that: step is as follows:

(1) boiling: get the quick growth poplar wood sheet, put into the digester boiling, get magma, then wash, screen, get paper pulp;

(2) xylanase pretr eatment;

(3) ECF bleaching: the above-mentioned paper pulp of processing through enzyme is bleached, and bleaching process is ODQP, O _PDQP or O ₁O _2PThree kinds of DQP float one of order, and the step of bleaching process is: at first, the paper pulp of processing through enzyme is carried out the deoxidation lignin or strengthens the deoxidation lignin; Oxygen delignification washs paper pulp after finishing, and then carries out D section ClO 2 bleaching; D section ClO 2 bleaching washs paper pulp after finishing, and then carries out Q section chelation treatment; Q section chelation treatment is washed paper pulp after finishing, and then carries out P section H ₂O ₂Bleaching is finished.

2. the sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar according to claim 1, it is characterized in that: the concrete mode of described boiling is: the quick growth poplar wood sheet of getting length 15～25mm, width 10～20mm, thickness 3～5mm, behind the natural air drying, carry out boiling, make fast-growing poplar sulfate magma, the condition of boiling is: alkali charge 20%, and to over dry raw material, Na ₂The O meter; Sulphidity 24%, liquor ratio 1:4,165 ℃ of boiling maximum temperatures, the 15min that in the time of 105 ℃, exits, heating-up time 120min, temperature retention time 90min; Fully wash after the boiling, screen, get paper pulp, the Kappa number of paper pulp is 16～21.

3. the sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar according to claim 1, it is characterized in that: the concrete mode of described xylanase pretr eatment is: adjusting pulp density is 10%, then uses zytase X ₁, X ₂Or X ₃Process, in processing procedure, every interval 10～15min rubs once; Take out after processing, put into boiling water bath 10min, make zytase inactivation cessation reaction, clean paper pulp with running water.

4. the sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar according to claim 3 is characterized in that: described zytase X ₁, X ₂Or X ₃The concrete technology condition of processing is as follows: X ₁The process conditions of processing: enzyme dosage 8IU/L, 50～55 ℃ of temperature, pH8, time 120min; X ₂The process conditions of processing: enzyme dosage 6IU/g, 55～60 ℃ of temperature, pH8～9, time 120min; X ₃The process conditions of processing: enzyme dosage 8IU/g, temperature 50 C, pH8～9, time 120min.

5. the sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar according to claim 1, it is characterized in that: the concrete mode of described ODQP bleaching process is: Oxygen Delignification of Fast-Growing is: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 80min, MgSO ₄Consumption 0.5%; D section: ClO ₂Consumption is 0.7%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA consumption 0.5%, temperature 70 C, time 60min, pH value 4～5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

6. the sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar according to claim 1 is characterized in that: described O _PThe concrete mode of DQP bleaching process is: strengthening the Oxygen Delignification of Fast-Growing condition is: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, MgSO ₄Consumption 0.5%, Na ₂SiO ₃Consumption 0.7%, H ₂O ₂Consumption 3%, time 80min; D section: ClO ₂Consumption is 0.5%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA consumption 0.5%, temperature 70 C, time 60min, pH value 4-5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

7. the sulfate pulp biochemical process ECF bleaching process of a kind of fast-growing poplar according to claim 1 is characterized in that: described O ₁O _2PThe concrete mode of DQP bleaching process is: first paragraph oxygen delignification and second segment are strengthened the process conditions of oxygen delignification: first paragraph O ₁: starch dense 10%, NaOH consumption 2.5%, oxygen is pressed 0.6MPa, 100 ℃ of temperature, time 20min, MgSO ₄Consumption 0.5%; Second segment O _2P: replenish 0.5% NaOH, add 3% H ₂O ₂, Na ₂SiO ₃Consumption 0.7%, oxygen is pressed 0.5MPa, time 60min; D section: ClO ₂Consumption is 0.5%, original ph 5, temperature 70 C, starch dense 10%, time 120min; The Q section: starch dense 8%, DTPA consumption 0.5%, temperature 70 C, time 60min, pH value 4-5; P section: H ₂O ₂Consumption is 2%, Na ₂SiO ₃Consumption 0.7%, MgSO ₄Consumption 0.5%, original ph 12,90 ℃ of temperature, starch dense 10%, time 90min.

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