CN101587054A - Method for measuring first pass retention of wet end rapidly - Google Patents

Abstract

The primary retention rate of paper stock is the main index to evaluate the retention of fibers and other solids on the forming wire during the sheet forming process in the wet end of papermaking. It is one of the important indicators of routine inspection in the production process of paper mills, and directly reflects whether the wet end is running normally or not. The method for quickly measuring the primary retention rate of the papermaking wet end of the present invention comprises the following steps: firstly, preparing the paper stock concentration; secondly, measuring the filtrate concentration; then measuring the filtrate turbidity; finally, according to the paper stock concentration, the filtrate concentration and the filtrate turbidity Calculate the primary retention rate according to the relevant formula. However, when the retention rate is tested according to the Tappi standard, the operation process is cumbersome, and relatively expensive testing equipment is required, which is very inconvenient. After several experiments and combined with relevant data, the inventor found that there is a good correlation between the filtrate concentration of the paper material after water filtration and the turbidity of the filtrate, and the paper material can be directly calculated from the filtrate concentration and the paper material concentration. retention rate.

Description

A kind of method of fast measuring first pass retention of wet end

One, technical field

The present invention relates to the detection method in the paper making wet part page forming process, specifically relate to the assay method of a retention in the paper making wet part page forming process.

Two, background technology

A retention is meant that the solid content that stays after paper stock is by the wire-cloth dehydration in page accounts for the percent of the total solid in the paper stock.And carry out with the paper machine that a large amount of to keep experiment be uneconomic, assess the influence of retention agent and the various chemical parameters of explanation so have only for a retention with experiment.Laboratory Britt dynamic drainage instrument commonly used carries out the detection research that paper stock is kept at present.But when carrying out the retention detection with the dynamic drainage instrument, operating process is more loaded down with trivial details, and the manual operation error is bigger, and need be equipped with relatively expensive detection equipment, and is very inconvenient.

When at present a retention that carries out the wet end paper stock in paper industry relevant enterprise and scientific research institutions is measured, be to carry out according to the Tappi standard basically, the method for a retention of Tappi standard test is as follows: the concentration 0.5% of at first preparing paper stock; Measure the concentration of filtrate then, get the paper stock that 500ml prepares and pour the dynamic drainage jar into, speed of agitator with 1500rpm fully stirs, then rotating speed is transferred to 750rpm, add the retention agent PAMC, after 10 seconds, 100ml filtrate before collecting, take by weighing the weight of this 100ml filtrate, counting its quality is G1, uses the filter paper filtering of constant weight, claim that its quality is G2, claim to be trapped in filter cake on the filter paper weight after together with the filter paper constant weight, remember that its quality is G3, obtains filter liquor concentration by following formula:

$c=\frac{(G_3-G_2)100}{G_1}\%$

C-filter liquor concentration in the formula, %,

G1-100ml filtrate quality, g,

Quality after the G2-filter paper constant weight, g,

G3-filters the quality after back filter cake and the filter paper process constant weight, g,

So repeat 3 times, get its mean value.

Calculate retention of paper stock according to the TAPPI standard method.TAPPI standard method computing formula is:

$\mathrm{FPR}(\%)=(1-\frac{c}{c_0})\×100$

Wherein: 100ml filter liquor concentration before the c-, %;

c ₀-paper stock concentration, %;

Three, summary of the invention

The object of the present invention is to provide a kind of method of fast measuring first pass retention of wet end.

The objective of the invention is to realize by following technical scheme:

The turbidity that detects web part of paper machine plain boiled water is very convenient quick, and personal error is less, can reflect the reservation situation of wet end paper stock qualitatively, but can't quantize.Can only so, turbidity index that a retention of qualitative reflection be carried out quantification?

1. this paper intends probing into the turbidity of the filtrate of collecting after the paper stock process dynamic drainage and the correlativity of its filter liquor concentration, thereby sets up the working curve of filtrate turbidity and its filter liquor concentration.And this curve carried out regretional analysis, draw corresponding math equation.Like this, we can be according to the filtrate turbidity, finds out the concentration data of filtrate under this turbidity by working curve, according to filter liquor concentration and known paper stock concentration, can ask a retention of calculating paper stock.Thereby making directly to be asked by turbidity index qualitatively calculates a quantitative retention index and is achieved.

A kind of method of measuring first pass retention of wet end is characterized in that the step of assay method is as follows:

(1) preparation of paper stock concentration:

To in the standard fibers fluffer, discongest by 2% concentration to the bleached reed pulp of degree Schopper-Riegler 58 degree through pulling an oar, add 25% winnofil then, after stirring again thin up to paper stock concentration be 0.5%, standby;

(2) mensuration of filtrate turbidity:

Get the paper stock that 500ml prepares and pour the dynamic drainage jar into, fully stir, then rotating speed is transferred to 750rpm with the speed of agitator of 1500rpm, add the retention agent PAMC, after 10 seconds, 100ml filtrate before collecting is with the turbidity of turbidimeter mensuration filtrate;

(3), can calculate the concentration of filtrate by the regression equation of correspondence according to the correlativity of filtrate turbidity and filter liquor concentration:

Collect the turbidity of step (2), by the filtrate turbidity regression equation y=(9 * 10 corresponding with the working curve of filter liquor concentration with turbidimeter mensuration filtrate ^-8) x2-(5 * 10 ^-5) x+0.0857, calculate the concentration of filtrate by the filtrate nephelometer of measuring, wherein the y=c in the regression equation;

(4) according to paper stock concentration, filter liquor concentration, by following formula, calculate one time retention FPR,

$\mathrm{FPR}(\%)=(1-\frac{c}{c_0})\×100$

The concentration of C-filtrate in the formula,

The concentration of Co-paper stock,

Perhaps:

Press the regression equation y=(9 * 10 of the working curve correspondence of filtrate turbidity and filter liquor concentration ^-8) x2-(5 * 10 ^-5) x+0.0857 calculates a retention FPR, y=c wherein, the substitution following formula is:

$\mathrm{FPR}(\%)=[1-\frac{(9\×{10}^{-8})X^2-(5\×{10}^{-5})X+0.0857}{c_0}]\×100$

X is the filtrate turbidity in the formula, and Co is a paper stock concentration.

The inventive method is compared with traditional assay method, has the following advantages:

From the method for a retention of Tappi standard test as can be seen, the present invention has the following advantages by comparison:

1. during retention of Tappi standard test, every survey once all need through weighing, filter, dry (4h in 105 ℃ the baking oven) thereby, constant weight records the concentration of filtrate, and is quite loaded down with trivial details; The concentration of 100ml filtrate before the present invention just need measure when the working curve of match filtrate turbidity and filter liquor concentration, after the working curve match is come out, only need get its preceding 100ml filtrate at every turn when measuring retention of paper stock again and survey its turbidity, find out the concentration of filtrate under this turbidity condition again by working curve, put things right once and for all;

2. retention of Tappi standard detection is consuming time longer relatively, because the concentration of 100ml filtrate before retention of Tappi standard test must be measured, we know that the mensuration filter liquor concentration will pass through and weigh, filters, dries operations such as (4h in 105 ℃ the baking oven), constant weight, and is consuming time oversize.And the present invention only need measure before 100ml filtrate turbidity, so the present invention to compare the Tappi standard method fast and simple many;

3. the used instrument of the present invention is simple and easy to, and can ask and calculates a corresponding retention because only need measure the filtrate turbidity, and the relative classic method of manual operation error reduces greatly.

Four, description of drawings

The relation curve of Fig. 1-filter liquor concentration and filtrate turbidity

Five, embodiment

Embodiment: the method for fast measuring first pass retention of wet end

1. experimental raw and mainly experimental apparatus

1.1 experimental raw and auxiliary material

Commodity bleaching KP reed pulp plate,

Filler winnofil (PCC), granularity is less than granule content＞98% of 2 μ m,

PAMC (it is standby to be made into 0.01% concentration), percol182,

1.2 experimental apparatus

Trough-style pulp beater ZQS2 type, machine works of Xibei College of Light Industry; DDJ dynamic drainage instrument electro-craft, motomatic; Turbidimeter 2100P type, U.S. HACH company; The circulation ability of swimming is used vacuum pump SHB-III type, Zhengzhou Greatwall Scientific Industrial ﹠ Trading Co., Ltd. more; The standard fibre device GBJ-A type that dissociates, Changchun small-scale test machine factory.

1.3 research step and method

1.3.1 the preparation of paper stock concentration

To in the standard fibers fluffer, fully discongest by 2% concentration to the bleached reed pulp of degree Schopper-Riegler 58 degree through pulling an oar, add 25% PCC then, after stirring again thin up to pulp density be 0.5% standby.

1.3.2 dynamically keep experiment

Get the paper stock that 500mL prepares in advance and pour the dynamic drainage jar into, the speed of agitator with 1500rpm fully stirs simultaneously, then speed of agitator is transferred to 750rpm.The CPAM that under this rotating speed, adds different additions, after 10 seconds, 100mL filtrate before collecting.Calculate a retention according to filter liquor concentration and paper stock concentration then, the computing method of a retention FPR are as follows ^{[2] ()}: (Liu Wenxia, Qiu Huayu. paper making wet part chemistry [M]. Chemical Industry Press, 104-106).

$\mathrm{FPR}(\%)=(1-\frac{c}{c_0})\×100$

In the formula: c, c ₀Be respectively the concentration (%) of filtrate and paper stock;

1.3.3 the mensuration of filter liquor concentration

Get 100ml filtrate collected among the 1.3.2, take by weighing this 100ml filtrate weight, remember that its quality is G ₁(weigh and remember that its quality is G with the filter paper of constant weight ₂) filter, (title is trapped in filter cake on the filter paper weight after together with the filter paper constant weight to constant weight, remembers that its quality is G ₃), can obtain filter liquor concentration;

Computing formula: $c=\frac{(G_3-G_2)100}{G_1}\%$

The c-filter liquor concentration, %,

G ₁-100ml filtrate quality, g,

G ₂Quality after the-filter paper constant weight, g,

G ₃Quality after-filtration back filter cake and the filter paper process constant weight, g,

So triplicate is got its mean value.

1.3.4 the mensuration of filtrate turbidity

Collect among the 1.3.2 filtrate of remainder except that 100ml, with the turbidity of filtrate under the HACH 2100P type turbidimeter mensuration different condition.

2. experimental result and discussion

2.1 bleaching KP reed pulp adds the corresponding relation of PCC system filter liquor concentration and turbidity

As can be seen from the above table, there is tangible corresponding relation in paper stock really through filter liquor concentration and its filtrate turbidity after the dynamic drainage, and along with the increase of filtrate turbidity, the filtrate turbidity also increases thereupon.So, whether the two exists certain mathematical relation, and it is the working curve of horizontal ordinate that the author attempts simulating with filtrate turbidity and concentration by regretional analysis.

See shown in Figure 1 2.2 bleaching KP reed pulp adds the working curve of PCC system filter liquor concentration and filtrate turbidity.

From the regretional analysis result of filtrate turbidity and filter liquor concentration, there are tangible two correlations in paper stock filtrate turbidity and filter liquor concentration, and related coefficient reaches 0.9936.A few groups of data substitution regression equations that fetch data in showing check, and calculated value and practical measurement result are very nearly the same.As with filtrate turbidity 1372NTU substitution equation y=(9 * 10 ^-8) x ²-(5 * 10 ^-5) x+0.0857, trying to achieve the filter liquor concentration value is 0.186%, and measured value is 0.181%, relative error only about 2%.With filtrate turbidity 277NTU substitution equation y=(9 * 10 ^-8) x ²-(5 * 10 ^-5) x+0.0857, trying to achieve the filter liquor concentration value is 0.07876%, and measured value is 0.08%, relative error only about 1.5%.

2.3 the dependent equation of retention and filtrate turbidity

Because retention can be according to following Equation for Calculating: $\mathrm{FPR}(\%)=(1-\frac{c}{c_0})\×100$

In the formula: c, c ₀Be respectively the concentration (%) of filtrate and paper stock

And the regression equation y=(9 * 10 corresponding with the working curve of filter liquor concentration according to the filtrate turbidity of match ^-8) x ²-(5 * 10 ^-5) x+0.0857, can calculate filter liquor concentration c, c by the filtrate nephelometer of measuring ₀For known, so can directly calculate retention FPR one time;

$\mathrm{FPR}(\%)=[1-\frac{(9\×{10}^{-8})X^2-(5\×{10}^{-5})X+0.0857}{c_0}]\×100$

X, c in the formula ₀Be respectively filtrate turbidity (NTU) and paper stock concentration (%)

3. conclusion

1. from experimental result, filtrate turbidity and filter liquor concentration have good quadratic dependence, and related coefficient reaches 0.9936.

2. according to the filtrate turbidity of bleached reed pulp and the analysis of reaching the same goal of concentration, the regression equation that draws the two is y=(9 * 10 ^-8) x ²-(5 * 10 ^-5) x+0.0857.

3. according to the equation of reaching the same goal of filtrate turbidity and filter liquor concentration, the work equation that can draw retention of paper stock and filtrate turbidity is $\mathrm{FPR}(\%)=[1-\frac{(9\×{10}^{-8})X^2-(5\×{10}^{-5})X+0.0857}{c_0}]\×100.$

Claims (1)

1. A method for measuring the primary retention rate of the wet end of papermaking, characterized in that the steps of the measuring method are as follows: (1) Preparation of paper stock concentration: The bleached reed pulp that has been beaten to a Shore beating degree of 58 degrees is decomposed in a standard fiber deflaking machine at a concentration of 2%, and then 25% of precipitated calcium carbonate is added, stirred evenly, and then diluted with water to a paper stock concentration of 0.5%. spare; (2) Determination of filtrate turbidity: Take 500ml of the prepared paper material and pour it into the dynamic water filter tank, fully stir at the stirring speed of 1500rpm, then adjust the rotating speed to 750rpm, add the retention aid cationic polyacrylamide, after 10 seconds, collect the first 100ml of filtrate, and use turbidity Measuring the turbidity of the filtrate with a turbidity meter; (3) According to the correlation of filtrate turbidity and filtrate concentration, the concentration of filtrate can be calculated by corresponding regression equation: collection step (2) measure the turbidity of filtrate with turbidimeter, press the ratio of filtrate turbidity and filtrate concentration The regression equation corresponding to the working curve y=(9×10 ^-5 )x2-(5×10 ^-5 )x+0.0857, the concentration of the filtrate is calculated by the measured filtrate turbidity, wherein y=c in the regression equation; (4) Calculate the primary retention rate FPR according to the paper stock concentration and filtrate concentration according to the following formula, $\mathrm{<span\; class="notranslate">\; FPR</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; \%</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; c</span>}}{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}$ In the formula, the concentration of C- filtrate Concentration of Co-paper stock or: According to the regression equation z=(9×10 ^-5 )x2-(5×10 ^-5 )x-0.0857 corresponding to the working curve of the filtrate turbidity and filtrate concentration, calculate the primary retention rate FPR, where y=c is substituted into the above formula for: $\mathrm{<span\; class="notranslate">\; FPR</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; \%</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.0857</span>}}{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}$ In the formula, X is the turbidity of the filtrate, and Co is the concentration of the paper stock.

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