CN109312537A - Dual alkali charging for tablet dipping - Google Patents
Dual alkali charging for tablet dipping Download PDFInfo
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- CN109312537A CN109312537A CN201780031762.XA CN201780031762A CN109312537A CN 109312537 A CN109312537 A CN 109312537A CN 201780031762 A CN201780031762 A CN 201780031762A CN 109312537 A CN109312537 A CN 109312537A
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- China
- Prior art keywords
- sieve
- alkali
- maceration extract
- charging
- steeper
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C1/00—Pretreatment of the finely-divided materials before digesting
- D21C1/06—Pretreatment of the finely-divided materials before digesting with alkaline reacting compounds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C3/00—Pulping cellulose-containing materials
- D21C3/22—Other features of pulping processes
- D21C3/24—Continuous processes
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C7/00—Digesters
- D21C7/06—Feeding devices
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C7/00—Digesters
- D21C7/12—Devices for regulating or controlling
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Abstract
The present invention relates to a kind of method and steepers, wherein a large amount of maceration extracts being added are the hot black liquor forms with remaining alkali content.Hot black liquor is added in central upper portion pipe, supply hot black liquor as maceration extract and flashes off steam to exorcise air from the cellulosic material of size degradation.During the first time steam treatment, it takes out from the timber acidity discharged in material and useless maceration extract with timber acidity content from top extraction sieve to recycle, lower part takes out sieve and remaining maceration extract is recycled to the second lower central pipe, with balanced alkali content well before the remaining retention time in steeper.According to the present invention, it is flat that the additional alkali being added in hot black liquor and recycling maceration extract is respectively depending on the gentle buck established below lower part taking-up sieve of the buck for taking out from top and establishing in the liquid that sieve takes out.
Description
Technical field
The present invention relates generally to wood chip is impregnated in the production process of chemical pulp, more particularly in not preparatory steam
The method for receiving the normal pressure steeper of tablet in the case where processing and carrying out alkali charging in this steeper, more specifically
The method for being related to steeper and carrying out dual alkali charging (double alkali charging) in normal pressure steeper.
Background technique
In traditional continuously cooking, wood chip is initially subjected to steam pre-treatment before being supplied to practical digestion process.Pre- place
Reason includes the temperature that tablet is heated to 70-100 DEG C first using low-pressure steam, is then steamed using flash-off steam or low pressure circulation
Tablet is again heated to 110-120 DEG C of temperature by vapour.Then the tablet Jing Guo thorough steam treatment is converted in tablet slot
Slurry is then fed to digestion process.In general, heating for the first time, second of heating and slurry are formed in different separated appearances
It is carried out in device.During the steam treatment, timber acidity is released, and the steam condensate formed during steam pre-treatment
The pH that can achieve about 4-5 is horizontal.Kamyr AB is tested to take out this acid vapors condensate in the factory of Sweden,
Because acidic condensate volume forms parasitic static load volume, which only just needs a large amount of alkali for its neutralization.
This acidic condensate and unsuccessful is discharged from vapor vessel, because outlet will soon be by the viscous precipitate from timber
Object blocking.Therefore, in the conventional decoction system with vapor vessel, acid static load volume, which only passes through, additionally to add a base to keep away
Exempt from.
In the U.S. Patent No. 8,647,469 (WO2012/026856) of Trolin et al., the steam of wood chip is eliminated
Pretreatment, but proposes a kind of method, this method include a) not to tablet carry out preparatory steam treatment and by its continuously into
The tablet by dipping is confessed from the bottom of the normal pressure steeper in the top for expecting normal pressure steeper；It b) will be hot by pipe
Maceration extract (black liquor) is added in steeper, and the outlet of the pipe is located under the tablet horizontal position established in steeper
Side；C) liquid level of the maceration extract of addition is established in steeper, so that tablet horizontal position is higher than at least 1-2 meters of the liquid level；
D) it is taken out from steeper in the horizontal position of liquid level and recycles the first maceration extract；E) at the first sieve row (screen row)
The second maceration extract is taken out in the horizontal position of lower section, wherein the second taking-up liquid is by for returning to the steeper below the first sieve row
Center, the second taking-up liquid may be diluted with alkaline detergent solution.The patent document is using Valmet ImpBinTMDipping
The improved example of the standard practices of system.In ImpBinTMIn system, usually using the however, residual base in hot black liquor on the first top
Whole alkali charging of the addition for tablet dipping at identical outlet height in central tube.System described in the patent document is also
Disclose how the first taking-up sieve ensures to take out most of parasitic timber acidity of release, followed by second takes out sieve,
Taken out maceration extract is recycled to be sufficiently mixed tablet and maceration extract in whole cross section, but without most timber
Acidity is taken out from taking-up sieve before.The top that sieve is preferably arranged to relatively close steeper is taken out, with
Just the remaining impregnation technology to occur in a low temperature of starting for 100 DEG C establishes uniform buck and puts down (due to non-pressure vessel), this is needed
It is lot more time to the core for making alkali penetrate into tablet.
Using Valmets ImpBinTMIn the most systems of technology installation, not using according to US8,647,469 pair
The separated processing of the maceration extract of taking-up mixes the liquid of taking-up because separated sieve row has been connected to single removal piece
Body.In addition, being added to ImpBinTMHot black liquor (i.e. part used beat cooking liquor) in steeper is early from boiling vessel is located at
It is taken out in the taking-up sieve of phase, this causes relatively high however, residual base horizontal, is enough to consume the alkali in steeper.It is described to disappear
Consumption is related with alkaline impregnation dipping tablet with neutralization and then.
But this method is along with some problems.Since the charging of entire alkali adds in the horizontal position of the first taking-up sieve
Material, and since liquid has the very big radial flow from the center of steeper to the taking-up sieve being arranged in chamber wall
It is dynamic, therefore in the presence of the risk that very big high-alkali residue evaporates in extraction.For example, when the boiling cork in boiling vessel, when
When high-alkali charging for dipping is conducive to improve entire slurry yield, high alkali loss is caused due to extracting there are sizable
Risk.This is equally applicable to have high-alkali charging or the high hardwood application for extracting flow.The high alkali loss of evaporation causes to recycle pot
The inorganic load of height on furnace.In the early stage of digestion process, high alkali loss is also required to the charging by increasing white liquor to mend
It repays, this typically results in unfavorable alkaline curve and also has to the ability of causticization again of a part usually as pulp mill negative
It influences.
Such as US 8, described in 647,469, the recycling for taking out sieve from second can be diluted with alkaline detergent solution and is impregnated
Liquid.But the system becomes insensitive for the variation of the technique, because the first taking-up may establish some conditions, such as low
PH, causes the blocking of the first taking-up sieve, and the second taking-up and recycling can be the dipping occurred below the second taking-up sieve
It is flat to establish nonideal buck.
The natural trend of tablet and the change of moisture content of tablet change the condition of the first taking-up, this takes out to by second
The alkalinity analysis established with recycling, which has, to be directly affected.In addition, if the condition in dipping or subsequent digestion process changes,
Then the variation of tablet is also the however, residual base level variation of hot black liquor.
Therefore, general purpose of the invention is to be reduced by realizing the charging of alap alkali during dipping and tablet
The relevant operating cost of impregnation technology.However, a purpose is in response to variation and the tablet of the wood material in being fed in technique
Bring water makes feed conditions adapt to the smallest alkali charging.The amount of water can change within one hour or shorter time, because
It is likely to be dependent on which portion collection of the tablet from timber heap for it, and may be long due to the storage time of snow, rain or tablet
It spends and changes.Another purpose is in response to the variation of the however, residual base level in the hot black liquor of supply dipping, adapts to feed conditions
The smallest alkali charging.In general, during the cooking process, in the continuous steamer in the screen portion of boiling vessel by the black liquor of heat from
Fixed position is taken out, wherein however, residual base is on close level stabilization during regular cook.However, the however, residual base level in hot black liquor can
It can change, because timber may have the different content of lignin of consumption alkali.In addition, if increasing of the digestion process due to production
Add or reduce and change, this may need to change the temperature of boiling and/or alkali charging, then however, residual base level will fluctuate.Another
Purpose is to reduce whole white liquor charging, to reduce the fuel consumption in limekiln.The purpose is to reduce the remnants of evaporation for another
Alkali number, this causes to recycle the inorganic load reduction in boiler.Another purpose is the alkalinity provided in steeper more evenly
Distribution, so as to cause improved, stock quality especially more evenly.
Summary of the invention
Above-mentioned purpose is realized by a kind of method and steeper, and this method and steeper are used for according to independence
Two positions of the impregnation technology of claim carry out additional alkali charging.It elaborates preferably to implement in the dependent claims
Mode.
The method according to the present invention that tablet is impregnated in chemical pulp production process, method includes the following steps: a)
Tablet is continuously sent to the top of normal pressure steeper in the case where not preparatory steam treatment, by dipping tablet from
It sends out the bottom of the normal pressure steeper；B) the first maceration extract charging comprising hot black liquor is added by dipping by the first central tube
The center of container, first central tube, which has, is located at the outlet that screening level position is taken out on top, and sieve is taken out on the top
Near the maceration extract liquid level established in steeper, and from steam is discharged in hot black liquor in maceration extract liquid level
The tablet of side carries out steam treatment；C) sieve is taken out by top and takes out a certain amount of useless maceration extract from steeper, and will
Useless maceration extract with release timber acidity content sends to recycling from tablet steam treatment；D) measurement is taken out sieve by top and is taken out
Useless maceration extract in alkali content, and the alkali content of the measurement is compared with the target value of alkali content；E) according to measurement
Comparison between alkali content and target alkali content adjusts and is added by the first maceration extract that steeper center is added in the first central tube
The alkali content of material, so that the alkali content taken out in the liquid that sieve takes out by top reaches minimum target value, the minimum mesh
Scale value avoids to be precipitated in useless maceration extract；F) sieve is taken out by lower part and takes out a certain amount of remaining leaching from steeper
Stain liquid, and the maceration extract of taking-up is returned to by steeper by the second central tube, which, which has, is located at lower part taking-up
The outlet of screening level position；The lower part is taken out sieve and is located at top taking-up sieve following distance, and the distance is than leaching
The diameter of stain container is short, and the reservation region of tablet, remote super dipping are established in the maceration extract for taking out sieve lower than the lower part
The 70% of total retention time in container；G) alkali content in the maceration extract of sieve taking-up is taken out in measurement by lower part, and by the survey
The alkali content of amount is compared with the target value of alkali content；H) according to the comparison between the alkali content of measurement and target alkali content,
The alkali content that the maceration extract that sieve takes out is taken out by lower part is adjusted, so that the alkali taken out in the liquid that sieve takes out by lower part contains
Amount reaches target value, for example, minimum target value, the target value provides foot for the remaining impregnation technology that lower part is taken out below sieve
Enough bucks are flat.
These step a) are to h) minimizing alkali loss in the following manner:
Top can be efficiently controlled in and take out the useless maceration extract taken out in sieve and its release timber acidity content, and
Alkali content is kept, taking-up sieve is avoided to be blocked.
The hot black liquor added in central tube can have different alkali residual contents, and additional alkali charging corrects for
Alkali content.Therefore, impregnation technology not will receive the influence for generating the variation of the subsequent digestion process of waste cooking liquid of heat.
It can be by controlling the remaining maceration extract for add aing base to adjust into recycling below top taking-up sieve, it is ensured that
It is taken out in the entire dip time below sieve in lower part and establishes alkali concentration appropriate.
These step a) are to h) further improving impregnation technology:
Impregnation technology becomes insensitive to the different cellulosic materials different in terms of timber acidity release of addition.
The different moisture content that impregnation technology becomes in the cellulosic material to addition is insensitive, and this different moisture content can
Can be due to storage during natural moisture variation and it is different, or due to during cold-weather operation and using routine
The increase for the snow and ice being concomitantly introduced into the open stacking storage of cellulosic material with cellulosic material.Add with cellulosic material
The pH that the water per ton added often influences during the release of timber acidity is horizontal.
In one preferred embodiment, the first maceration extract charging feeds comprising additional lye, lye charging
Alkali concentration is higher than the remaining alkali concentration of hot black liquor.Therefore, it is possible to use the lye from pulp mill's different piece, such as: it comes from
The alkaline washing filtrate of boiling vessel washing or paper pulp bleaching washing, the weak liquid from causticization and the green liquor from causticization.
In another preferred embodiment, additional lye charging also may include white liquor, wherein the first leaching is added
The amount of white liquor in the charging of stain liquid is conditioned, so that taking out the alkali content that sieve takes out by top reaches target value.It can make
Use white liquor as the source with highest alkali concentration, because of the charging small volume of this needs.The white liquor can also be white with aoxidizing
Liquid replaces.
In another alternate embodiments, the charging of the second maceration extract feeds comprising additional lye, lye charging
Alkali concentration is higher than the remaining alkali concentration that the maceration extract that sieve takes out is taken out by lower part.In addition, lye may include white liquor or alkali
Concentration is higher than any liquid that the alkali concentration for the maceration extract that sieve takes out is taken out by lower part, and the second dipping is added wherein adjusting
The amount of lye in liquid charging is so that the alkali content that lower part takes out below sieve reaches target value.
In the preferred embodiment of the method for the present invention, it can be surveyed being taken out in the dipping liquid stream taken out in sieve from lower part
The alkali content that amount is established in maceration extract by second maceration extract charging.The alkali content of the liquid of taking-up and close steeper
Remaining alkali content in the tablet of wall is identical, therefore also identical as the lower part taking-up alkali content of lower section of sieve is adjacent to.But
It is the best applications of sensor that sensor is applied in taking out pipe.
Alternatively, the outlet of the steeper at sieve following distance can be taken out in steeper or in lower part
The alkali content that place's measurement is established in maceration extract by second maceration extract charging.This measurement can by steeper or
The sensor in steeper exit or the liquid of steeper bottommost take out the sensor in pipeline and carry out.Sensor this
Kind positioning can effectively monitor the pH in entire impregnation stage and keep sufficiently high.But due to low temperature dipping area (most 100
DEG C start) delignification react caused by alkali consumption it is very low because of the low H factor, lower part taking-up sieve in biography
Sensor position may be enough highly precisely to estimate final ph.
It is essentially all that the useless leaching that sieve takes out is taken out by top in another preferred embodiment of the method for the present invention
Stain liquid can be conveyed to recycle.This solution will extract the parasitism of the timber acidity discharged from impregnation technology as much as possible
Static load volume, to reduce the amount of the additional alkali added in compared with low circulation.
It is essentially all that the liquid that sieve takes out is taken out by lower part in the last preferred embodiment of the method for the present invention
It can collect in the second trapped volume, then return to leaching by being connected to the pipe of the second trapped volume and the second central tube
In stain container.This will reinforce taking out the radial balanced stream established between sieve in the outlet of the second central tube and lower part, impregnate
Also uniform alkali distribution is established in the whole cross section (from center to wall) of container.
The physical Design of normal pressure steeper of the present invention for impregnating tablet in chemical pulp production process includes:
Sieve is taken out on top, is arranged at the first level position in the chamber wall of steeper；
First central tube, one end are connected to the source of supply hot black liquor, and the outlet of the other end is located at top and takes out sieve
At first level position；
Pipe, one end are connected to alkali source, and the outlet of the other end is connected to the first central tube, and is equipped with the first regulating valve, uses
It feeds in the alkali for adjusting additional in the first maceration extract charging being added in steeper by the first central tube；
Sieve is taken out in lower part, is arranged the second horizontal position in chamber wall (2), and second horizontal position is lower than the
One takes out the first level position of sieve (3)；With
Second central tube, one end are connected to lower part and take out sieve, and export and the level that sieve is taken out in lower part is arranged in
At position.The design further include:
One pipe, one end are connected to alkali source, and the outlet of the other end is connected to the first central tube, and is equipped with first and adjusts
Valve, for adjusting alkali charging additional in the first maceration extract charging being added in steeper by the first central tube；
One pipe, one end are connected to alkali source, and the outlet of the other end is connected to the second central tube, and is equipped with second and adjusts
Valve, for adjusting the additional alkali charging that the second central tube is added；
The first regulating valve pair is adjusted for detecting the alkali content taken out in the useless maceration extract that sieve takes out by top and passing through
The device that additional alkali charging in the charging of first maceration extract is adjusted；With
For detecting the alkali content in the maceration extract that lower part takes out below sieve and by adjusting the second regulating valve to the
The device that additional alkali charging in the charging of two maceration extracts is adjusted.
Brief Description Of Drawings
Non-limiting example will be passed through below and the present invention is explained further making reference to the attached drawings, in which:
Fig. 1 is the schematic diagram for the top for impregnating the steeper of wood chip in chemical pulp production process；With
Fig. 2 is that liquid road is substituted in the top of the steeper for impregnating wood chip in the production process of chemical pulp
The schematic diagram of line.
Preferred embodiment is described in detail
The normal pressure steeper for impregnating wood chip in the production process of chemical pulp is schematically shown in Fig. 1
The embodiment on 1 top.Steeper 1 includes substantially cylindrical chamber wall 2, wherein the first taking-up sieve 3 is set
At first level position, the second taking-up sieve 4 is arranged on the second horizontal position lower than first level position.Due to
One horizontal position is higher than the second horizontal position, so first takes out the also referred to as top taking-up sieve 3 of sieve 3, and second takes out
Sieve 4 is also referred to as lower part and takes out sieve 4.It takes out the liquid that sieve 3 takes out and collects in first be arranged in chamber wall 2 in top
In trapped volume 5, and the liquid that sieve 4 takes out is taken out by lower part and is collected in the second trapped volume 6.Steeper 1 further includes
The first central tube 7 with outlet 8, in the embodiment shown in figure 1, outlet 8, which is arranged in, takes out the first of sieve 3 than first
The slightly higher position in horizontal position.However, outlet 8 can be arranged in the position more slightly lower than the first level position of the first taking-up sieve 3
It sets, or is arranged in horizontal position identical with the first taking-up first level position of sieve 3.The outlet of first central tube is opposite
In first taking-up sieve horizontal position accurate location for successfully realize advantage of the invention be not it is vital, only
Want the outlet of the first central tube be located substantially at first or top take out sieve horizontal position be sufficient.
Steeper 1 further includes the second central tube 9 with outlet 10, and in Fig. 1,10 setting of outlet is being taken out than second
The slightly higher position in second horizontal position of sieve 4, still, such as the outlet 8 of the first central tube 7, outlet 10 is located substantially at second
The second horizontal position for taking out sieve 4 is sufficient.Without using single first central tube, such as the first central tube 7, taken on top
The horizontal position of sieve terminates out, but multiple central tubes or the first central tube with a smaller size can be used
Outlet, such as outlet 8 of the first central tube 7, are segmented into several outlets, pass through the heat of the first maceration extract addition more with acquisition
Good distribution, and generation alkali gradient due to caused by neutralization reaction during the radial displacement of maceration extract can also be reduced.For
Similar reason can also replace the second central tube 9 with multiple central tubes of smaller size, and second central tube 9 is lower
The horizontal position for taking out sieve terminates or the outlet of the second central tube, such as the outlet 10 of the second central tube 9, is segmented into
Several outlets.
As described above, by top take out sieve 3 take out and collect the waste liquid in the first trapped volume 5 be conveyed to evaporation with
REC is recycled, this is carried out in Fig. 1 by pipe 11, and pipe 11 takes out 3 fluid connection of sieve with top by the first trapped volume 5.It will
The taking-up of sieve 4 is taken out by lower part and collects the liquid in the second trapped volume 6 and is sent into pipe 12, pipe 12 passes through the second trapped volume
6 take out 4 fluid connection of sieve with lower part.
It is not conveyed to recycle by the liquid that the taking-up of sieve 4 is taken out in lower part and introduces pipe 12, but pipe 12 is connected in second
Heart pipe 9, therefore the liquid being contained in pipe 12 returns in steeper 1 (as shown in phantom in fig. 1).Therefore, including under
Portion's taking-up sieve 4, pipe 12 and the second central tube 9 and its system for exporting 10 are mainly used for the circulation of liquid, and preferably, by
Lower part takes out the liquid that sieve 4 takes out and is not all conveyed to recycle, but within the scope of the invention, it can will be taken out by lower part
The sub-fraction liquid that sieve 4 takes out sends to recycling.Liquid is taken out by the second taking-up sieve 4 and the taking-up liquid passes through pipe
12 and second the size of central tube 9 back to circular flow caused by steeper 1 should be preferably sufficiently large, theoretically can be with
Replace the amount of the free fluid of timber per ton.
Other than other details of Fig. 1 illustrated embodiment, some of the operation of steeper 1 are shown below and show
Example property figure.Being added to the maceration extract in tablet by the first central tube 7 can be the mixture of black liquor and black liquor.It is remaining in black liquor
The amount of effective alkali can be about 10-30g/l (as EANaOH), and in white liquor the amount of effective alkali can be about 100-120g/l (as
EA NaOH).Black liquor is fed by the first charge pipe 13, and the first charge pipe 13 is connected to the first center by the first regulating valve 14
Pipe 7, and white liquor is fed by the second charge pipe 15, the second charge pipe 15 is connected to the first central tube 7 by the second regulating valve 16.
In another kind arrangement (not shown), the second charge pipe may be coupled to the first charge pipe, so that only one charge pipe
Directly it is connect with the first central tube.
Now, according to the present invention, remaining alkali number can be very low in the waste liquid taken out by top taking-up sieve 3, and can
With down to about 3-5g/l.This may be to have brought excessive water into tablet as caused by many reasons, such as a), reduce alkali
Concentration；B) due to the variation of timber, the release of timber acidity may be bigger than normal condition；C) or since the condition of cooking zone changes,
However, residual base level in hot black liquor is likely lower than normal level.It preferably, should in the liquid taken out by top taking-up sieve 3
There are a small amount of alkali residues, to ensure the blocking for having the alkali of sufficient amount to take out sieve to avoid first, but also for first
The horizontal position for taking out sieve 3 carries out initial tablet dipping.It can be at least about in general, taking out enough alkali contents in liquid
8g/l, but exact alkali concentration can differ ± 2g/l, and this depends on the type of the timber of dipping.
The alkali number in the liquid that sieve 3 takes out can be taken out by top by standard device and method measurement, and is led to
The amount for crossing the white liquor of the second charge pipe 15 addition is controlled via the second regulating valve 16 so as to be fed in pipe 11 and be evaporated
Alkali residual volume in liquid reaches target value.That is, if the alkali number in the liquid taken out by the first taking-up sieve 3 is higher than
Less white liquor is then added in target value into central tube 7, and if alkali residual volume is lower than target value, by more white liquors
It is added in central tube 7.
System can have fixed target value, such as during operation 20-60 hours, the fixation target value with 8g/l,
But it can also change in about 1-5 hours and arrive slightly higher target value, during this period, if it is desired, can be carried out to sieve is taken out
Cleaning.Clean needs can be detected by taking out the pressure drop monitoring above sieve, wherein sieve blocking often generates more
Big pressure drop.However, residual base level in extract is maintained close to floor level can save a large amount of alkali at any time, and subtract
Technical load in few removal process.The effective alkali number of residue, that is, use needed for providing further dipping by third charge pipe 17
Tablet impregnation section below the horizontal position for occurring mainly in lower part and taking out sieve 4, the third charge pipe 17 have the
Three regulating valves 18 are simultaneously connected to the second central tube 9, make to take out the maceration extract recycling that sieve takes out by lower part, so that this is remaining
Alkali charging can be added to the center of steeper 1 by the second central tube 9, and be distributed in the radial direction that sieve is taken out towards lower part
In the whole cross section of displacement.It is preferably white liquor form by the alkali that third charge pipe 17 is added；From the point of view of a viewpoint, the present invention
A kind of steeper and a kind of method are provided, white liquor total amount needed for thus effectively impregnating tablet in steeper is in two steps
It is added in first level position and the second horizontal position, restrictive condition is the alkali in the liquid that first level position periphery is taken out
Content should keep lower, but be higher than floor level, and the alkali content in the maceration extract below the second horizontal position should
It is sufficiently high, to meet entire impregnation technology.
It takes out, can be brought by tablet by having the non-blocking sieve of minimum alkali loss effectively take out by first
Most of timber acidity and water, this in itself reduces the alkali chargings in the second horizontal position.
Minimum water may remain in for the alkali charging into dipping main part occurred below the second horizontal position
It is flat, because neutralizing the alkali for only needing fraction for any remaining timber acidity, and cause since delignification reacts
The consumption of alkali be inappreciable because temperature is only about 100 DEG C.The purpose of dipping is to arrive alkaline impregnation infiltration tablet
In its core, alkali is consumed in process of osmosis without reacting due to delignification.This leads to the tablet and steaming being sufficiently impregnated
Volume of waste after boiling is reduced, that is, reduces uncooked tablet fragment.
In order to obtain uniform alkalinity distribution in the tablet content of steeper 1, it is shown below in steeper 1 not
Some exemplary values of the liquid wood than (liquor-to-wood ratio) at same level position.Sieve 3 is taken out first
Horizontal position can establish the liquid wood ratio of about 4-7, and in the region for taking out between sieve 3 and the second taking-up sieve 4 first,
Liquid wood ratio can be about 3-5, and can be in the liquid wood ratio for the horizontal position foundation about 3-6 for taking out sieve 4 lower than second.This
Outside, it is taken out higher than first between sieve 3 and the second taking-up sieve 4 if the liquid wood of the horizontal position of the first taking-up sieve 3 compares
Region in liquid-wood ratio, then should take out more waste liquids by the first taking-up sieve 3, and recycling is sent by pipe 11；Such as
Fruit first takes out water of the liquid-wood than taking out 4 lower section of sieve less than second in the region between sieve 3 and the second taking-up sieve 4
Prosposition sets the liquid wood ratio at place, then more white liquors should be added into tablet object by third charge pipe 17 and the second central tube 9.
The invention mainly relates to a kind of normal pressure steeper and a kind of methods, thus will be added to the material by steeper
Total alkali charging in piece object is divided into two steps, so that by alkali addition steeper and wherein at two different level positions
In contained tablet.
It is believed that passing through the alkali content and and alkali in the waste liq that first takes out sieve taking-up at measurement upper level position
The target value of content is compared, and allows to adjust (such as iteratively adjusting) and adjustment in the horizontal position of the first taking-up sieve
For the amount for the alkali that the place of setting is added by the first central tube when reaching target value, advantage of the invention obtains best realization.
It is automatically or manually controlled
As shown in Figure 1, this measurement can be completed online with sensor S1 and S2, for example, with measuring device AM300TMWith
Kemotron is carried out, they are based on conductivity measurement, and by Valmet AB companies market.Sensor may be coupled to
Local control unit CPU or factory control system DCS.
As disclosed in fig. 2, the measurement for the alkali content in the liquid that sieve takes out being taken out by first can be alternatively
It is offline in the lab to carry out, such as the sample of the taking-up liquid extracted in position X1 and X2 is sent to for periodic analysis
Laboratory, such as daily or analyzed according to normal frequency.Fig. 2 also discloses the fluid route of substitution, wherein
The liquid taken out from the first sieve 3 is connect using branch with the liquid taken out from the second sieve 4, and the balance of liquid flowing can
To be controlled by pump P1 and P2.When P1 is connected near pipe 11, the body volume for being sent to recycling will be the body from sieve 3
Product, and the body volume for being sent to central tube 9 will be the volume from sieve 4.This connection using branch is so that from each
A withdrawal amount for taking out sieve can keep total withdrawal amount constant with temporary variations.
However, having taken out the alkali content in the liquid that sieve takes out by first without actual measurement, the present invention is provided
A possibility that alkali charging is divided into casings in twice (mainly in the form of white liquor), significant advantage has been provided in this, for example,
In terms of the total alkali distribution in the alkali loss and steeper of extraction operation.It does not measure and is taken out by first in the liquid that sieve takes out
Alkali content, and can be based on the lumber consumption tested in the lab to estimate through the first central tube in upper water prosposition
Set the amount for the alkali that place is added, such as the tablet retention time based on the horizontal position for taking out sieve on top and from steeper
Center to the radial fluid flow of its wall, and be used to further impregnate remaining alkali needed for tablet object and existed by the second central tube
At lower horizontal position, i.e., the horizontal position that sieve is taken out in lower part is added.
The present invention provides the best applications of lye.In ImpBin beforeTMIn system, the supply of hot black liquor is had been given
The buck of the limit is flat, is enough pH value when taking out first and is maintained on precipitating level, and second takes out the surplus of lower section
The however, residual base level of remaining dipping is higher than floor level.In general, entire decoction system is designed to make to take out sieve in cooking zone
In position certain however, residual base for ensuring to meet the requirements it is horizontal, and not extraly by akaline liquid be added hot black liquor or
In recycling maceration extract in the circulation of lower section.When steady-state operation decoction system blocking first take out sieve when or if tablet
Dipping when not reaching target, usually only consider to add additional akaline liquid into dipping.
Although detailed description of the preferred embodimentsthe present invention has been described by reference to being also shown in the accompanying drawings, for this field skill
For art personnel it is readily apparent that can describe in the description and the scope of the present invention defined in the appended claims in into
The many change and modification of row.In instances, upper and lower part takes out sieve and is respectively shown as single sieve row, but they can be with
It respectively include multiple sieve rows.The present invention other maceration extract can also be supplied (such as AQ- additive etc.) be added to it is any
In central tube.
Claims (10)
1. a kind of method for impregnating tablet in chemical pulp production process, the described method comprises the following steps:
A) tablet is continually fed into the top of normal pressure steeper (1) in the case where not preparatory steam treatment, by leaching
The tablet of stain is sent out from the bottom of the normal pressure steeper；
B) the first maceration extract charging comprising hot black liquor is added to the center of steeper by the first central tube (7), described the
One central tube (7), which has, is located at the outlet (8) that sieve (3) horizontal position is taken out on top, and the top takes out sieve (3) and is located at leaching
Near the maceration extract liquid level established in stain container, and from steam is discharged in hot black liquor to the material being located above maceration extract liquid level
Piece carries out steam treatment；
C) sieve (3) are taken out by top and takes out a certain amount of useless maceration extract from steeper (1), and there will be release timber
The useless maceration extract of acidity content sends to recycling from tablet steam treatment；
D) alkali content taken out in the useless maceration extract that sieve (3) take out by top is measured, and the alkali content of the measurement is contained with alkali
The target value of amount is compared；
E) it according to the comparison between the alkali content of measurement and target alkali content, adjusts and dipping appearance is added by the first central tube (7)
The alkali content of the first maceration extract charging at device (1) center, so as to take out the alkali content in the liquid that sieve (3) take out by top
Reach minimum target value, the minimum target value avoids to be precipitated in useless maceration extract；
F) sieve (4) are taken out by lower part and takes out a certain amount of remaining maceration extract from steeper, and pass through the second central tube
(9) maceration extract of taking-up is returned into steeper, second central tube (9), which has, is located at lower part taking-up sieve (4) horizontal position
The outlet set；The lower part is taken out sieve and is located at top taking-up sieve following distance, and the distance is more straight than steeper
Diameter is short, and the reservation region of tablet, total security in far super steeper are established in the maceration extract for taking out sieve lower than the lower part
Stay the 70% of time；
G) alkali content taken out in the maceration extract that sieve (4) take out by lower part is measured, and the alkali content of the measurement is contained with alkali
The target value of amount is compared；
H) it according to the comparison between the alkali content of measurement and target alkali content, adjusts and the dipping that sieve (4) take out is taken out by lower part
The alkali content of liquid, so that the alkali content taken out in the liquid that sieve (4) take out by lower part reaches target value, the target value is
It is flat that the enough bucks of remaining impregnation technology offer below sieve (4) are taken out in lower part.
2. the method as described in claim 1, which is characterized in that the charging of the first maceration extract feeds comprising additional lye, described
The alkali concentration of lye charging is higher than the remaining alkali concentration of hot black liquor.
3. method according to claim 2, which is characterized in that additional lye charging includes white liquor, wherein the first leaching is added
The amount of white liquor in the charging of stain liquid is conditioned, so that taking out the alkali content that sieve (3) take out by top reaches target value.
4. the method as described in claim 1, which is characterized in that the charging of the second maceration extract feeds comprising additional lye, described
The alkali concentration of lye charging is higher than the remaining alkali concentration that the maceration extract that sieve (4) take out is taken out by lower part.
5. method as claimed in claim 4, which is characterized in that lye includes that white liquor or alkali concentration are higher than through lower part taking-up sieve
Net (4) take out maceration extract alkali concentration any liquid, wherein adjust be added the second maceration extract charging in lye amount with
So that the alkali content that lower part takes out below sieve (4) reaches target value.
6. method as claimed in claim 5, which is characterized in that taken out in the dipping liquid stream taken out in sieve (4) from lower part
The alkali content that measurement is established in maceration extract by second maceration extract charging.
7. method as claimed in claim 5, which is characterized in that in steeper (1) or steeper (1) outlet
The alkali content that place's measurement is established in maceration extract by second maceration extract charging.
8. the method as described in claim 1, which is characterized in that essentially all to take out the useless leaching that sieve (3) take out by top
Stain liquid is all conveyed to recycling (REC).
9. the method as described in claim 1, which is characterized in that essentially all to take out the liquid that sieve (4) take out by lower part
Body is all collected in the second trapped volume (6), then by being connected to the pipe of the second trapped volume (6) and the second central tube (9)
(12) it returns in steeper (1).
10. a kind of for impregnating the normal pressure steeper (1) of tablet in chemical pulp production process comprising:
Sieve (3) are taken out on top, the first level position being arranged in the chamber wall (2) of steeper (1)；
First central tube (7), one end are connected to the source of supply hot black liquor, and the outlet (8) of the other end is located at top and takes out sieve
(3) at first level position；
It manages (15), one end is connected to alkali source (WL), and the outlet of the other end is connected to the first central tube (7), and is equipped with second and is adjusted
Save valve (16), for adjusts by the first central tube (7) be added in steeper (1) the first maceration extract charging in additionally
Alkali charging；
Sieve (4) are taken out in lower part, and the second horizontal position being arranged in chamber wall (2), second horizontal position is lower than
First takes out the first level position of sieve (3)；With
Second central tube (9), one end are connected to lower part and take out sieve (4), and export (10) setting and take out sieve in lower part
(4) horizontal position, which is characterized in that
One pipe (15), one end are connected to alkali source (WL), and the outlet of the other end is connected to the first central tube (7), and are equipped with the
Two regulating valves (16), for adjusting volume in the first maceration extract charging being added in steeper (1) by the first central tube (7)
Outer alkali charging；
One pipe (17), one end are connected to alkali source (WL), and the outlet of the other end is connected to the second central tube (9), and are equipped with the
Three regulating valves (18), for adjusting the additional alkali charging that the second central tube (7) are added；
The second regulating valve (16) are adjusted for detecting the alkali content taken out in the useless maceration extract that sieve (3) take out by top and passing through
The device that additional alkali charging in the charging of first maceration extract is adjusted；With
It is for detecting the alkali content in the maceration extract that lower part takes out below sieve (4) and right by adjusting third regulating valve (18)
The device that additional alkali charging in the charging of second maceration extract is adjusted.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE1650742 | 2016-05-27 | ||
| SE1650742-8 | 2016-05-27 | ||
| PCT/SE2017/050555 WO2017204736A1 (en) | 2016-05-27 | 2017-05-23 | Double alkali charging for chip impregnation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109312537A true CN109312537A (en) | 2019-02-05 |
Family
ID=60412891
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201780031762.XA Withdrawn CN109312537A (en) | 2016-05-27 | 2017-05-23 | Dual alkali charging for tablet dipping |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20190194867A1 (en) |
| EP (1) | EP3464714A4 (en) |
| CN (1) | CN109312537A (en) |
| BR (1) | BR112018070795A2 (en) |
| WO (1) | WO2017204736A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI128975B (en) * | 2018-11-22 | 2021-04-15 | Andritz Oy | An arrangement for installation of monitoring sensors of a treatment vessel for lignocelllulosic material |
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| US20020129911A1 (en) * | 2000-10-16 | 2002-09-19 | Marcoccia Bruno S. | Process and configuration for providing external upflow/internal downflow in a continuous digester |
| SE0104272L (en) * | 2001-12-17 | 2002-11-12 | Kvaerner Pulping Tech | Process and arrangement for impregnating wood chips |
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| SE538452C2 (en) * | 2014-11-07 | 2016-07-05 | Valmet Oy | Method for operating a two vessel digester system |
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- 2017-05-23 CN CN201780031762.XA patent/CN109312537A/en not_active Withdrawn
- 2017-05-23 WO PCT/SE2017/050555 patent/WO2017204736A1/en unknown
- 2017-05-23 BR BR112018070795A patent/BR112018070795A2/en not_active IP Right Cessation
- 2017-05-23 EP EP17803173.8A patent/EP3464714A4/en not_active Withdrawn
- 2017-05-23 US US16/302,851 patent/US20190194867A1/en not_active Abandoned
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|---|---|---|---|---|
| CN1064117A (en) * | 1990-12-17 | 1992-09-02 | 国际专利公司 | Under pressure state, continuous steamer is carried out feed to obtain the method for cellulose pulp |
| US5203963A (en) * | 1991-10-21 | 1993-04-20 | A. Ahlstrom Corporation | Continuous treatment of small chips |
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Also Published As
| Publication number | Publication date |
|---|---|
| US20190194867A1 (en) | 2019-06-27 |
| WO2017204736A1 (en) | 2017-11-30 |
| BR112018070795A2 (en) | 2019-02-05 |
| EP3464714A4 (en) | 2019-12-25 |
| EP3464714A1 (en) | 2019-04-10 |
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Application publication date: 20190205 |