CN1350091A - Pan grinder bleaching process of italian poplar APMP pulp and process optimizing method - Google Patents

Abstract

The present invention discloses an optimized disc-grinding and bleaching process of Italian poplar pulp, and is mainly characterized by that in first stage of disc grinding adding bleaching agent to make disc grinding and bleaching to make pulp, and optimizing the processes of wood chips washing, presteaming, extruding, soaking, second-stage grinding, screening and bleaching so as to reduce the consumption of chemicals for making Italia poplar APMP pulp and raise its quality. Said invention uses 20-50% matched quantity of APMP pulp, and can make high-grade colored printing news-paper, offset printing book-magazine paper, double gummed paper and LWC (light weight coating) paper, etc.

Description

Italy's poplar APMP pulp mill bleaching and process optimization method

Technical field

The present invention relates to a kind of cellulose containing raw material italian poplar APMP pulping process, especially APMP association with pulp bleaching.

Background technology

Chemical-mechanical pulping is a pulping process very flexibly, shows that especially it can adopt different Chemical Pretreatment flow processs.At present, generally adopt cold alkali pre-impregnating process (CCS), alkaline sulfite pretreating process (CTMP) and alkaline peroxide pretreating process (APMP).APMP technology grows up on CTMP technology basis, and its slurrying characteristics are that slurrying and bleaching are united two into one, and finish bleaching process in the time of slurrying; Because of not using sulphite in the pulping process, waste water is the compound of sulfur-bearing not, and environment protection treating is relatively easy; Can select to flood hop count, NaOH, H according to assortment and the desired intensity of slurry and whiteness ₂O ₂Consumption; Adaptability to raw material is wider, is the very fast promising chemical mechanical pulp-making method of a kind of development.

APMP pulping process route is generally operations such as wood chip washing, presteaming, two sections extruding, two sections dippings, two sections normal pressure defibrinations, screening, bleaching.The raw material northern China generally adopts white poplar, Cathay poplar, birch, and leaf wood fast growing woods such as Eucalyptus, italian poplar are adopted in south.Our company is a raw material to abound with in the italian poplar of Lake Dongting area, adopts operation production APMP such as wood chip washing, presteaming, one section extruding, one section dipping, two sections defibrinations (a section is that normal pressure grinds for pressure mill, two sections), screening, bleaching to starch.Because this production line is a domestic first bar italian poplar APMP pulping production line, there is not experience to use for reference, understand not enough to abounding with in the italian poplar property of raw material of Lake Dongting area in addition, a period of time output, quality, consumption did not reach technological requirement after this production line was gone into operation, and had seriously restricted the purposes of change machine slurry.

Summary of the invention

For overcoming above-mentioned defective, the purpose of this invention is to provide a kind of Italian poplar APMP pulp mill bleaching and process optimization method, it can reduce the chemicals consumption, can improve soup preimpregnation effect again, improves the paper pulp light scattering coefficient, improves pulp quality.

For achieving the above object, technical scheme of the present invention is as follows: a kind of Italian poplar APMP pulp mill bleaching and process optimization method, comprise wood chip washing, presteaming, extruding, dipping, two sections defibrinations, screening, bleaching and APMP quality testings, and it is characterized in that:

(1) temperature of steaming the storehouse in advance is 90～100 ℃, adopts one section extruding, and wood chip extrusion spiral compression ratio is 4: 1;

(2) adopt one section dipping, the chemicals consumption during dipping/bleaching is to the percentage by weight of oven dry stock: NaOH4.0～6.0/1.5～2.5, H ₂O ₂2～4/1.5～2.5, Na ₂SiO ₃3.5/2.4, MgSO ₄7H ₂O0.3/0.4;

(3) one sections defibrinations are the pressure mill, and two sections defibrinations are the normal pressure mill, add bleaching agent and carry out the mill bleaching in one section mill, float agent and add at the afterbody of pressure conveyor screw, enter in one section pressure mill through board-like feeder;

(4) pressurized screen is a slotted screen, and sieve seam width is 0.15～0.45mm;

(5) pulp quality is: beating degree 〉=50 ° SR, tear index 〉=3.5mN.m ²/ g, fracture length 〉=2.6Km floats preceding whiteness/whiteness 56～62%/72～74% after floating.

Can join with the adapted amount of 20～50%APMP slurry and to be ferreted out high-grade newsprint for color printing, offset paper, wood-free paper, LWC paper kinds such as (light weight coated papers).

By carrying out the mill bleaching to adding an amount of agent of floating in one section mill of italian poplar alkaline hydrogen peroxide CTMP (APMP); Improve wood chip squeezing effect and soup preimpregnation effect, improve the preliminary treatment effect; Change and optimize the input that the abrasive disc profile of tooth improves mechanical energy; Adjust screening concentration and pressure and optimize the screening quality of slurry, make and float 2 percentage points of the total consumption reductions of agent, the quality of APMP slurry can satisfy LWC, wood-free paper, colored offset printing newsprint etc. and copy joining of multiple paper.Outside guaranteeing that paper pulp certain intensity and whiteness are constant, the paper pulp light scattering coefficient is by 33m ²/ kg brings up to 44m ²More than/the kg, beating degree is brought up to 50 ° more than the SR by 35 ° of SR, and ton slurry cost is reduced to present about 2300 yuan by 3500 yuan, reaches output and benefit doulbe-sides' victory.Because the APMP slurry not only has the strength character advantage of long fiber chemical pulp, and has a chemi-mechanical pulp optical property advantage, the Italian poplar APMP pulp that adopts this technology to produce is joined paper kinds such as copying high-grade newsprint for color printing, offset paper and LWC paper by 20～50% adapted amounts.Prepared paper product whiteness is good, the opacity height, and printing performance is good, is greatly favored by consumers, and wherein joins the LWC paper wad of copying and has mended domestic blank, obtains national new product, and has successfully exported to Japan; Adopt this technology, existing production line is brought up to more than 80 ton per days from 50 ton per days, ton slurry production cost has reduced 386 yuan, and 8,940,000 yuan of year saving production costs have good economic benefit; This Study on Technology and successful implementation when obtaining obvious economic benefit, have reduced the slurrying pollutional load, and China's development fast growing wood pulping and paper-making is had great guidance and reference function, have remarkable social benefit and ecological benefits.

The specific embodiment

The over dry wood chip that embodiment 1:1000kg conforms to quality requirements, through the hot wash of wood chip rinsing maching, after removing silt, ironware and part wood chip, entering pre-steaming storehouse again adds low-pressure steam and steams in advance, make the wood chip temperature in the storehouse reach 90～100 ℃, it is to push in 4: 1 the wood chip extruder that the wood chip after pre-the steaming enters compression ratio.Wood chip after the extruding enters the preimpregnation device, adds admixing medical solutions and H at preimpregnation device place ₂O ₂Admixing medical solutions: NaOH50kg, Na ₂SiO ₃30kg, MgSO ₄7H ₂O4kg, H ₂O ₂30kg.Wood chip enters reaction warehouse absorb soup in the preimpregnation device after, and the wood chip that goes out reaction warehouse enters the decatize pipe behind punishment in advance plug spiral extruding part raffinate, and the wood chip process single-screw discharger in the decatize pipe is to the pressure conveyor screw.Floating agent adds at the afterbody of pressure conveyor screw, through entering one section pressure mill behind the board-like feeder, the whiteness that goes out one section pressurized refining can reach 60%, screening behind two sections normal pressure mills again, pressurized screen is a slotted screen, and sieve seam width is 0.2mm, makes paper pulp 900kg, its pulp quality is: beating degree 〉=55 ° SR, tear index 〉=3.8mN.m ²/ g, fracture length 〉=3.0Km floats preceding whiteness/whiteness 56%/74% after floating.

Claims (1)

1. an Italian poplar APMP pulp mill is bleached and the process optimization method, comprises wood chip washing, presteaming, extruding, dipping, two sections defibrinations, screening, bleaching and APMP quality testings, it is characterized in that:

(1) temperature of steaming the storehouse in advance is 90～100 ℃, adopts one section extruding, and wood chip extrusion spiral compression ratio is 4: 1;

(2) adopt one section dipping, the chemicals consumption during dipping/bleaching is to the percentage by weight of oven dry stock: NaOH4.0～6.0/1.5～2.5, H ₂O ₂2～4/1.5～2.5, Na ₂SiO ₃3.5/2.4, MgSO ₄7H ₂O0.3/0.4;

(3) one sections defibrinations are the pressure mill, and two sections defibrinations are the normal pressure mill, add bleaching agent and carry out the mill bleaching in one section mill, float agent and add at the afterbody of pressure conveyor screw, enter in one section pressure mill through board-like feeder;

(4) pressurized screen is a slotted screen, and sieve seam width is 0.15～0.45mm;

(5) pulp quality is: beating degree 〉=50 ° SR, tear index 〉=3.5mN.m ²/ g, fracture length 〉=2.6Km floats preceding whiteness/whiteness 56～62%/72～74% after floating.