CA1103967A - Method of producing a fibrous mass from peat and means for carrying out the method - Google Patents
Method of producing a fibrous mass from peat and means for carrying out the methodInfo
- Publication number
- CA1103967A CA1103967A CA332,522A CA332522A CA1103967A CA 1103967 A CA1103967 A CA 1103967A CA 332522 A CA332522 A CA 332522A CA 1103967 A CA1103967 A CA 1103967A
- Authority
- CA
- Canada
- Prior art keywords
- peat
- suspension
- fiber
- sorting operation
- humidification
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01B—MECHANICAL TREATMENT OF NATURAL FIBROUS OR FILAMENTARY MATERIAL TO OBTAIN FIBRES OF FILAMENTS, e.g. FOR SPINNING
- D01B1/00—Mechanical separation of fibres from plant material, e.g. seeds, leaves, stalks
- D01B1/50—Obtaining fibres from other specified vegetable matter, e.g. peat, Spanish moss
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10F—DRYING OR WORKING-UP OF PEAT
- C10F5/00—Drying or de-watering peat
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10F—DRYING OR WORKING-UP OF PEAT
- C10F7/00—Working-up peat
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Textile Engineering (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Paper (AREA)
- Absorbent Articles And Supports Therefor (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to a method of producing a fibrous mass from peat.
It has not been possible in the past to produce an easily dewaterable fibrous mass from peat when using in the production a continuous process which (1) could be carried out with a minimum amount of manpower, (2) enables a higher yield from the peat moors than had been the case before, (3) enables an efficient separation of colloids and particles smaller than 0.2 mm, and (4) enables the use of a simple equipment which, by a quickly made replacement of a screening member, can be changed to match the nature of the digged-up peat.
The object of the present invention was to obviate this problem which, according to the invention is realized substan-tially by the features that, after a primary sorting operation, the peat material suspension is liquid-concentration regulated by supplying thereto an amount of liquid depending on the degree of humidification of the digged-up peat, and then supplying the suspension under pressure to at least one screening member having a permeability depending on the peat-fibre concentration of the peat material after said concentration regulation.
The present invention relates to a method of producing a fibrous mass from peat.
It has not been possible in the past to produce an easily dewaterable fibrous mass from peat when using in the production a continuous process which (1) could be carried out with a minimum amount of manpower, (2) enables a higher yield from the peat moors than had been the case before, (3) enables an efficient separation of colloids and particles smaller than 0.2 mm, and (4) enables the use of a simple equipment which, by a quickly made replacement of a screening member, can be changed to match the nature of the digged-up peat.
The object of the present invention was to obviate this problem which, according to the invention is realized substan-tially by the features that, after a primary sorting operation, the peat material suspension is liquid-concentration regulated by supplying thereto an amount of liquid depending on the degree of humidification of the digged-up peat, and then supplying the suspension under pressure to at least one screening member having a permeability depending on the peat-fibre concentration of the peat material after said concentration regulation.
Description
~1~3~i7 The present invention relates to a method of producing a fibrous mass from peat, comprising carefully exposing the fibres of the peat-fibre material and transferring the same into a peat-material suspension which is subjected to a grading (or: screening, classifying, assorting) operation.
It has not been possible in the past to produce an easily de-watered fibrous mass from peat while using in the pro-duction a continuous process which (1) could be carried out with a minimum of manpower requirements, (2) enables a greater yield from the peat-moors than had been the case before, (3) enables an efficient separating out of colloids and particles less than 0.2 mm, and (4) enables the employment of a simple installation, which, by a quickly made replacement of a screening member, can be changed to match the character of the digged-up peat.
The present invention has for its object to obviate these problems, and this, according to the invention is mainly realized by the fact that, after a primary sorting step, the peat-material suspension is subjected to a liquid concentration (or consistency) regulation by supplying thereto an amount of liquid ~20 depending~on the degree of humidi~icationof the digged-up peat, and ;:
then ~supplying the suspension under pressure to at least one ~ screening member having a permeability depending on the peat-fibre ~ concentration of the peat-material suspension after said concen-- ~ ~
tratlon regulation, The present invention therefore provides a method of producing a peat fiber concentrate comprising the steps of:
a) measuring the degree of humldification of raw peat . on~a~peat moor;
: b) excavating peat from the peat moor;
c) suspending the excavated peat in water;
1: ` . .
i, ~, : . -- 1 --, . . . . :
.
35~7 d) subjecting the peat suspension from step b) to a primary sorting operation wherein oversize material is removed from said suspension;
e) adjusting the peat fiber concentration of the sorted peat suspension from step d) by adding to said suspension an amount of water sufficient to provide a selected peat fiber concentration one percent by weight or less depending upon the initial degree of humidification of the raw peat whereby the consistency of the peat suspension is adjusted to a desired level;
f) providing a screening member having a selected per-meability depending upon the adjusted peat fiber concentration of the peat suspension from step e); and g) subjecting the peat suspension from step f) to a secondary sorting operation by passing the suspension through said screening member to produce a concentrated peat fiber suspension and a substantially fiber-free effluent containing colloids and particles less than 0.2 mm in si~e.
The inventive method will be described more in detail hereinafter with reference to the accompanying drawing which is a diagrammatic illustration of a plant for producing a fibrous mass from peat. The diagrammatically illustrated plant comprises a carriage 1 or the like which can be moved on a peat-moor. The carriage 1 carries a pump 2 having at least one spray nozzle tnot shown) emitting a water jet for defibrating peat material ~ on the moor. ~he pumpable peat material suspension thus obtained ; ~ (having a peat-fibre concentration of 1 to 6% by wèight) is taken up by rneans of a take-up pump 3 and is conveyed by the latter ; through a conduit 4 to a primary sorting assembly 5 comprising, for exàmple, at least one rotary, perforated screen having a central intake for the incoming stuff, or inject. In the primary 9~7 sorting assembly 5, material greater than about 10 mm in si~e is separated, involving that about 10 to 20~ of the peat material of the suspension is separated out (through conduit 6 in the drawing). The material separated out (i.e. the rejected stuff, or reject) has a peat fibre concentration of about 6% and is suitable, for example, for burning or for soil-improvement purposes.
The accepted stuff, or accept, obtained after the primary sorting assembly 5 is a suspension with pumpable consistency because a very small proportion only of the liquid has been re-moved in the primary sorting assembly 5. This suspension, whichcontains fibre particles smaller than about 10 mm, including col-loids and particles smaller than 0.2 mm, is passed through a conduit 7 to a liquid supplying assembly 8 comprising, for example, a collecting tank with a water inlet 9.
In the liquid supply assembly 8 a liquid, suitably water, is supplied in an amount such as to impart to the peat material suspension a peat-fibre concentration less than 1% by weight.
The higher degree of humidification of the peat-material of the moor, the more water is supplied in order to obtain a lower peat-20~ fibre concentration.
From the table below it will be seen what peat-fibre concentration is aimed at by supplying water at different degrees of humidification (H) of the raw peat material from the moor:
;Degree of Humidification (H) Water supplied in the Water Supply as measured on the peat moor: Assembly to reach the following peat-fibre concentration of the suspension:
0~ o 3 max about 1% by weight 3~to 6 max about 0.75% by weight 30 above 6 max abou~ 0.5% by weight , ~ :
; - 3 -~ ' : ' ~ . . , . ~ .: - . . .
The consistency regulated peat-fibre suspension, which thus has a peat-fibre concentration lower than about 1~ by weight, is supplied through a conduit 10 to an assembly 11 for separating colloids and particles smaller than about 0.2 mm. This assembly 11 comprises for instance a screening member having through-flow perforations about 1 mm in diameter, or smaller.
The size of the through-flow perforations of the screen-ing member of the assembly 11 is determined in relation to the concentration of the suspension and the degree of humidification of the peat material. The more humidified peat in the suspension and the lower its concentration, the smaller the perforations of the screening member should be in order to obtain the greatest possible yield of accept, i.e. the maximum possible amount of easily drainable peat-fibre material.
From the following table, it is seen what yield of easily drainable peat-fibre mass can be obtained at various degrees of humidification, various peat-fibre concentrations and various per-foration or mesh sizes of the screening member of the assembly 11:
Degree of humidification Peat-fibre con- Hole or mesh Yield %
20 (H)(according to von centration in % size of sc~n Post's scale) by weight 0 to 3 0.75 - 1 about 1 ~, 3 - 6 0.5 - 0.75 0.5~- 1 about 80-90 above 6 0.1 - 0.5 max. 0.5 about 70-90 - fine-mesh net or cloth It is seen from this table, that it i5 possible to obtain a very high yield (i.e. usable proportion of the completely treated peat), independently of the degree of humidification of the peat moor simply by supplying a suitable amount of water ; 30 to obtain a suitable peat-fibre concentration, and by using in ; ' ~ .
.
D3~7 the assembly 11 a screening member having an adequate hole or mesh size.
At a peat fibre concentration in excess of about 1~
by weight and a larger mesh size of the screening member than 1 mm, an essentially lower yield will be obtained, and at higher peat-fibre concentra-tions and constant mesh si~e, for example, there will be a great danger of clogging the plant, resulting in a breakdown of the operation of the mill.
By utilizing in the process the values listed in the last mentioned table, a peat-fibre concentration increase of at least 100% will be obtained in the assembly 11, involving that about 50~ of the water supplied is removed, thereby removing also at least 50% of the colloids and particles smaller than about 0 2 mm (through the condult 12, possibly for returning to the moor).
The peat-fibre concentration of the suspension after the assembly 11 has a maximum of about 2% by weight, and the suspension now has a character such that it can be passed ~through a conduit 13) to and received by a take-up assembly 14 comprising an ordinary take-up filter, whereby the peat-fibre concentration can be increased in a simple way to about 10% by welght and, in ,~
addition, at least 75% of the remaining colloids and particles ; smaller than about 0.2% are carried away with the effluent Water which flows away through the conduit 15, possibly for returning to~the or) The accept stuff obtained is carried away through a~conduit 16 to be used, for instance, for papermaking, as a substance for cleaning purposes, for increasing the dry-substance content of various reject stuffs, as a fuel or as a soil improve-ment substance, or fertilizer.
` 30 Thus, by utilizing the method described, a peat-fibre ` I
:.: '1 ~,, ~ , ' '. : :' : - ' . . : .. : ' . :
concentration increase from lower than 1% by weight to about 10%
by weight will be obtained. In practicing the production method of the invention, of course, more than one primary sorting assembly or unit 5 and more than one secondary sorting assembly or unit 11 can come into use.
It is advantageous to add the water (or other suitabl~
liquid) after the primary sorting unit 5. It is essential that the water supplied through the conduit from the water supply unit is devoid of suspended particles. In other words, it is not suitable to use water directly from the peat moor, but this water will have to be cleaned from suspended particles, since otherwise the effect of the following separation process would be reduced.
To provide an extremely simple equipment-for carrying out the method of the invention, the primary sorting unit 5 comprises a screening member, preferably in the form of a rotary drum 5a with perforations 5b of a diametrical size of about 10 mms. The peat-material suspension is passed into this drum by the conduit 4, the rejected stuff being passed out from the drum -~5a through the conduit 6, while the accept stuff is obtained by 20~ retaining the suspension passing through the perforations 5b.
.
This accepted stuff is carried away through the conduit 7 and :: ~
th~rough~the liquld supply unit 8 after supplying liquid through the ~conduit 10 to the secondary sorting unit 11. The latter comprises at least one stationary screening member lla having perforatiOns or holes llb the sizes of which can vary as stated -~
in~the~table reerred to hereabove. In the present case the portion of~the su~pension which cannot pass through the screening member ll~a is retalned as accepted stuff and is passed further through conduit 13, whereas the portion of the suspension passing `; ::
t~rough the screening member lla is removed as rejected stuff through conduit 12.
j: ~
1 :
~ - 6 -. , , . ~ . .
.
Peat material treated according to the inventive method, and preferably with the employment of the inventive equipment, can, without any difficulties, by mechanical drainage and without any s~lpply of heat have imparted to it a peat-fibre concentra-tion of about 40 to 45% by weight.
The sorting or classifying operation can comprise more than one primary sorting step and more than one secondary sorting step. The primary and secondary sorting steps may be carried out in one single sorting or classifying unit, for instance at different positions in one single screening assembly.
The circuitry of the plant may be provided with or re-placed by pressurizing elernents (not shown and not described in detail, since pressurizing elements of any type previously known to those skilled in the art may be used) to supply the diluted suspension under pressure to the screening unit ll (preferably being a so-called arc screen).
It may be mentioned, finally, that the expression "par-ticles smaller than about 0.2mms." involves particles which totalIy are of sizes smaller than 0.2 mms, but preferably also ~20 particles whose smallest outer measures are about 0.2 mm, but ;:
whose largest outer measures may be larger. Thus, for instance, a particle comprised by this conception may have a length sub-stantially larger than about 0.2 mm, but a width less than about 0~ 2 ~mm~
Von~Post's scale is described in: -"Planeringsrapport, Torv i Sverige 1977:1", a planning report made by the "Namnden for Energiproduktions:s Planning Board for Peat".
The suspension effluent through conduit 12 and/or conduit 15 and contalning organic materials (predominantly colloids and particles smaller than 0.2mm) from the peat moor, ~' which remain after the primary sorting step and the fibre - 7 ~
~ ~ v ., .
separation following thereafter, is subjected to a separation process in which the organic matter is separated out from the fibre-free suspension, after which the dry substance content of the organic matter is increased by dewatering the same. The organic matter thus dewatered, after storage and/or transport may suitably again be mixed with water to be spread out over a ground area, for instance, to serve as a soil melioration agent and/or to form a covering layer serving, i.a., to preserve humidity in the underlying soil.
The organic matter is suitably separated out of the fibre-free suspension by a sedimentation process, the sedimenta-tion being brought about by causing the peat-fibre concentration of the peat material suspension to be less than about 0.5~ by weight when the degree of humidification of the digged-up peat is higher than 6 according to von Post's scale. In the last sedimentation step it may be suitable to add a flocculent, pre-ferably a polymer, alum or other salts, in order to accelerate the sedimenting effect.
Thé separation of organic matter from the fibre-free suspension may suitably be carried out in a plant of the type shown in Fig. 3. This plant comprises a settling basin 17 into which the fibre-free suspension is supplied through the conduit 12 and/or 15. In this settling basin the organic matter is allowed to settle to the bottom, and the water, in a well--known manner, is allowed to flow off at the top edge of the basin 17 and is carried away through gutters or chutes 18. The organic matter coll cted in the bottom portion of the basin 17 is pumped by a pumping equipment l~ through a conduit 20 into a second settling basin 21, the pumped suspension containing 4 to 10% dry substance by weight, preferably 5 to 7% dry substance. In order to obtain "~
.
e-Lficient sedimentation, the settling basin 21 is provided at its top with laminae22 arranged in a manner previously known per se over which water can pass before flowing over the top edges of the basin 21 to be passed away in a purified state through effluent channels 23. In order to accelerate the sedimentation efficiency in the basin 21, a flocculating agent, for instance a polymer, alum or other salts may be supplied from a stora~e 24 to increase the weight of the organic particles so that they will sink at a greater velocity. The organic matter collected in the bottom portion of the basin is pumped out from the basin 21 by a pump equipment 25, and the pumpable suspension is furnished through a pipe line 26 to a dewatering station 27. At this station the suspension is dewatered, for instance by a pressing and/or centrifuging process, until the accepted stuff, the accept, has a dry substance content of at least 10~ by weight and up to 2~%
dry substance. The high dry substance content now obtained has the advantage that the accept (shown as a block and designated by 28) will be handy, that it can be stacked in a space-saving manner -without any need of particular storage equipments, and that it 20 can be transpor~ed at low cost for further use. -~
.
The material blocks 28 are conveyed in their "dry condition" to a utilization area 29 where it is mixed with water . . ~ .
so as to be spread out together therewith. At the utilization area 29 the blocks 28 may be supplied into a container 30 with ; water in which the blocks 28 readily dissolve. The container 30 i: : .: . .
; is connected through a conduit 31 to a water-carrying conduit 32 of a conventional irrigation plant 33, whereby organic-matter-containing water will be drawn up by ejector action from the ; container 30 and supplied to the stream of water flowing in ~30 conduit 32. The water admixed with organic matter is sprayed _ g _ .
.
: , . - .': ,- ' ' ' ' : ' :
through noæzles 34 over a field 35 and is deposited as a thin film 36 on this field. When this film has dried, it may be continuously tight if the concentration of organic matter is maintained sufficiently high. The film 36 thus formed may be utilized for preventing wind erosion and for preserving h~midity in the underlying soil. It further has soil melioration proper-ties and thus can be used as a soil melioration agent, in which case it is mixed with the organic dry substance in a manner to cause 10 to 20 g dry substance to be spent on each square meter of the field surface. The film also is well adapted to coat sown seeds, particularly when they lie superficially and are especially sensitive during the germination period.
In order to increase the dry substance content of the accept stuff obtained from the separation process, the latter may have dry substance 37 added to it, for instance peat substance from the same peat moor 38 from which the peat fibres, too, have been taken. 5aid dry substance 37 may be added instead of pres-` sing and/or centrifuging or in combination therewith.
-~ Portions of the dewatered accept stuff can be used for producing material for combustion purposes or for lubrication purposes, or as raw materials for chemical industry or as additives in casting.
The separation process described hereinbefore is suitably a sedimentation process, but other methods for separating the organi~c material can also be applied. The different stages and units of the plant illustrated in Figure 3 can be varied within wide llmits without departing from the general scope of the invention.
s, The inventive methodology implies the advantage that not only the peat fibres, but also smaller particles are made use of so that the peat-fibre extraction will only reject roots and other larger components of the peat moor and pure or sub-stantially pure water. These remnant products may be disposed of (for example returned into the peat moor) without any danger ~ - -of interference with the natural environment.
~ .
,; ' .
. - i ... ,............. ~ , - - ': : , - -
It has not been possible in the past to produce an easily de-watered fibrous mass from peat while using in the pro-duction a continuous process which (1) could be carried out with a minimum of manpower requirements, (2) enables a greater yield from the peat-moors than had been the case before, (3) enables an efficient separating out of colloids and particles less than 0.2 mm, and (4) enables the employment of a simple installation, which, by a quickly made replacement of a screening member, can be changed to match the character of the digged-up peat.
The present invention has for its object to obviate these problems, and this, according to the invention is mainly realized by the fact that, after a primary sorting step, the peat-material suspension is subjected to a liquid concentration (or consistency) regulation by supplying thereto an amount of liquid ~20 depending~on the degree of humidi~icationof the digged-up peat, and ;:
then ~supplying the suspension under pressure to at least one ~ screening member having a permeability depending on the peat-fibre ~ concentration of the peat-material suspension after said concen-- ~ ~
tratlon regulation, The present invention therefore provides a method of producing a peat fiber concentrate comprising the steps of:
a) measuring the degree of humldification of raw peat . on~a~peat moor;
: b) excavating peat from the peat moor;
c) suspending the excavated peat in water;
1: ` . .
i, ~, : . -- 1 --, . . . . :
.
35~7 d) subjecting the peat suspension from step b) to a primary sorting operation wherein oversize material is removed from said suspension;
e) adjusting the peat fiber concentration of the sorted peat suspension from step d) by adding to said suspension an amount of water sufficient to provide a selected peat fiber concentration one percent by weight or less depending upon the initial degree of humidification of the raw peat whereby the consistency of the peat suspension is adjusted to a desired level;
f) providing a screening member having a selected per-meability depending upon the adjusted peat fiber concentration of the peat suspension from step e); and g) subjecting the peat suspension from step f) to a secondary sorting operation by passing the suspension through said screening member to produce a concentrated peat fiber suspension and a substantially fiber-free effluent containing colloids and particles less than 0.2 mm in si~e.
The inventive method will be described more in detail hereinafter with reference to the accompanying drawing which is a diagrammatic illustration of a plant for producing a fibrous mass from peat. The diagrammatically illustrated plant comprises a carriage 1 or the like which can be moved on a peat-moor. The carriage 1 carries a pump 2 having at least one spray nozzle tnot shown) emitting a water jet for defibrating peat material ~ on the moor. ~he pumpable peat material suspension thus obtained ; ~ (having a peat-fibre concentration of 1 to 6% by wèight) is taken up by rneans of a take-up pump 3 and is conveyed by the latter ; through a conduit 4 to a primary sorting assembly 5 comprising, for exàmple, at least one rotary, perforated screen having a central intake for the incoming stuff, or inject. In the primary 9~7 sorting assembly 5, material greater than about 10 mm in si~e is separated, involving that about 10 to 20~ of the peat material of the suspension is separated out (through conduit 6 in the drawing). The material separated out (i.e. the rejected stuff, or reject) has a peat fibre concentration of about 6% and is suitable, for example, for burning or for soil-improvement purposes.
The accepted stuff, or accept, obtained after the primary sorting assembly 5 is a suspension with pumpable consistency because a very small proportion only of the liquid has been re-moved in the primary sorting assembly 5. This suspension, whichcontains fibre particles smaller than about 10 mm, including col-loids and particles smaller than 0.2 mm, is passed through a conduit 7 to a liquid supplying assembly 8 comprising, for example, a collecting tank with a water inlet 9.
In the liquid supply assembly 8 a liquid, suitably water, is supplied in an amount such as to impart to the peat material suspension a peat-fibre concentration less than 1% by weight.
The higher degree of humidification of the peat-material of the moor, the more water is supplied in order to obtain a lower peat-20~ fibre concentration.
From the table below it will be seen what peat-fibre concentration is aimed at by supplying water at different degrees of humidification (H) of the raw peat material from the moor:
;Degree of Humidification (H) Water supplied in the Water Supply as measured on the peat moor: Assembly to reach the following peat-fibre concentration of the suspension:
0~ o 3 max about 1% by weight 3~to 6 max about 0.75% by weight 30 above 6 max abou~ 0.5% by weight , ~ :
; - 3 -~ ' : ' ~ . . , . ~ .: - . . .
The consistency regulated peat-fibre suspension, which thus has a peat-fibre concentration lower than about 1~ by weight, is supplied through a conduit 10 to an assembly 11 for separating colloids and particles smaller than about 0.2 mm. This assembly 11 comprises for instance a screening member having through-flow perforations about 1 mm in diameter, or smaller.
The size of the through-flow perforations of the screen-ing member of the assembly 11 is determined in relation to the concentration of the suspension and the degree of humidification of the peat material. The more humidified peat in the suspension and the lower its concentration, the smaller the perforations of the screening member should be in order to obtain the greatest possible yield of accept, i.e. the maximum possible amount of easily drainable peat-fibre material.
From the following table, it is seen what yield of easily drainable peat-fibre mass can be obtained at various degrees of humidification, various peat-fibre concentrations and various per-foration or mesh sizes of the screening member of the assembly 11:
Degree of humidification Peat-fibre con- Hole or mesh Yield %
20 (H)(according to von centration in % size of sc~n Post's scale) by weight 0 to 3 0.75 - 1 about 1 ~, 3 - 6 0.5 - 0.75 0.5~- 1 about 80-90 above 6 0.1 - 0.5 max. 0.5 about 70-90 - fine-mesh net or cloth It is seen from this table, that it i5 possible to obtain a very high yield (i.e. usable proportion of the completely treated peat), independently of the degree of humidification of the peat moor simply by supplying a suitable amount of water ; 30 to obtain a suitable peat-fibre concentration, and by using in ; ' ~ .
.
D3~7 the assembly 11 a screening member having an adequate hole or mesh size.
At a peat fibre concentration in excess of about 1~
by weight and a larger mesh size of the screening member than 1 mm, an essentially lower yield will be obtained, and at higher peat-fibre concentra-tions and constant mesh si~e, for example, there will be a great danger of clogging the plant, resulting in a breakdown of the operation of the mill.
By utilizing in the process the values listed in the last mentioned table, a peat-fibre concentration increase of at least 100% will be obtained in the assembly 11, involving that about 50~ of the water supplied is removed, thereby removing also at least 50% of the colloids and particles smaller than about 0 2 mm (through the condult 12, possibly for returning to the moor).
The peat-fibre concentration of the suspension after the assembly 11 has a maximum of about 2% by weight, and the suspension now has a character such that it can be passed ~through a conduit 13) to and received by a take-up assembly 14 comprising an ordinary take-up filter, whereby the peat-fibre concentration can be increased in a simple way to about 10% by welght and, in ,~
addition, at least 75% of the remaining colloids and particles ; smaller than about 0.2% are carried away with the effluent Water which flows away through the conduit 15, possibly for returning to~the or) The accept stuff obtained is carried away through a~conduit 16 to be used, for instance, for papermaking, as a substance for cleaning purposes, for increasing the dry-substance content of various reject stuffs, as a fuel or as a soil improve-ment substance, or fertilizer.
` 30 Thus, by utilizing the method described, a peat-fibre ` I
:.: '1 ~,, ~ , ' '. : :' : - ' . . : .. : ' . :
concentration increase from lower than 1% by weight to about 10%
by weight will be obtained. In practicing the production method of the invention, of course, more than one primary sorting assembly or unit 5 and more than one secondary sorting assembly or unit 11 can come into use.
It is advantageous to add the water (or other suitabl~
liquid) after the primary sorting unit 5. It is essential that the water supplied through the conduit from the water supply unit is devoid of suspended particles. In other words, it is not suitable to use water directly from the peat moor, but this water will have to be cleaned from suspended particles, since otherwise the effect of the following separation process would be reduced.
To provide an extremely simple equipment-for carrying out the method of the invention, the primary sorting unit 5 comprises a screening member, preferably in the form of a rotary drum 5a with perforations 5b of a diametrical size of about 10 mms. The peat-material suspension is passed into this drum by the conduit 4, the rejected stuff being passed out from the drum -~5a through the conduit 6, while the accept stuff is obtained by 20~ retaining the suspension passing through the perforations 5b.
.
This accepted stuff is carried away through the conduit 7 and :: ~
th~rough~the liquld supply unit 8 after supplying liquid through the ~conduit 10 to the secondary sorting unit 11. The latter comprises at least one stationary screening member lla having perforatiOns or holes llb the sizes of which can vary as stated -~
in~the~table reerred to hereabove. In the present case the portion of~the su~pension which cannot pass through the screening member ll~a is retalned as accepted stuff and is passed further through conduit 13, whereas the portion of the suspension passing `; ::
t~rough the screening member lla is removed as rejected stuff through conduit 12.
j: ~
1 :
~ - 6 -. , , . ~ . .
.
Peat material treated according to the inventive method, and preferably with the employment of the inventive equipment, can, without any difficulties, by mechanical drainage and without any s~lpply of heat have imparted to it a peat-fibre concentra-tion of about 40 to 45% by weight.
The sorting or classifying operation can comprise more than one primary sorting step and more than one secondary sorting step. The primary and secondary sorting steps may be carried out in one single sorting or classifying unit, for instance at different positions in one single screening assembly.
The circuitry of the plant may be provided with or re-placed by pressurizing elernents (not shown and not described in detail, since pressurizing elements of any type previously known to those skilled in the art may be used) to supply the diluted suspension under pressure to the screening unit ll (preferably being a so-called arc screen).
It may be mentioned, finally, that the expression "par-ticles smaller than about 0.2mms." involves particles which totalIy are of sizes smaller than 0.2 mms, but preferably also ~20 particles whose smallest outer measures are about 0.2 mm, but ;:
whose largest outer measures may be larger. Thus, for instance, a particle comprised by this conception may have a length sub-stantially larger than about 0.2 mm, but a width less than about 0~ 2 ~mm~
Von~Post's scale is described in: -"Planeringsrapport, Torv i Sverige 1977:1", a planning report made by the "Namnden for Energiproduktions:s Planning Board for Peat".
The suspension effluent through conduit 12 and/or conduit 15 and contalning organic materials (predominantly colloids and particles smaller than 0.2mm) from the peat moor, ~' which remain after the primary sorting step and the fibre - 7 ~
~ ~ v ., .
separation following thereafter, is subjected to a separation process in which the organic matter is separated out from the fibre-free suspension, after which the dry substance content of the organic matter is increased by dewatering the same. The organic matter thus dewatered, after storage and/or transport may suitably again be mixed with water to be spread out over a ground area, for instance, to serve as a soil melioration agent and/or to form a covering layer serving, i.a., to preserve humidity in the underlying soil.
The organic matter is suitably separated out of the fibre-free suspension by a sedimentation process, the sedimenta-tion being brought about by causing the peat-fibre concentration of the peat material suspension to be less than about 0.5~ by weight when the degree of humidification of the digged-up peat is higher than 6 according to von Post's scale. In the last sedimentation step it may be suitable to add a flocculent, pre-ferably a polymer, alum or other salts, in order to accelerate the sedimenting effect.
Thé separation of organic matter from the fibre-free suspension may suitably be carried out in a plant of the type shown in Fig. 3. This plant comprises a settling basin 17 into which the fibre-free suspension is supplied through the conduit 12 and/or 15. In this settling basin the organic matter is allowed to settle to the bottom, and the water, in a well--known manner, is allowed to flow off at the top edge of the basin 17 and is carried away through gutters or chutes 18. The organic matter coll cted in the bottom portion of the basin 17 is pumped by a pumping equipment l~ through a conduit 20 into a second settling basin 21, the pumped suspension containing 4 to 10% dry substance by weight, preferably 5 to 7% dry substance. In order to obtain "~
.
e-Lficient sedimentation, the settling basin 21 is provided at its top with laminae22 arranged in a manner previously known per se over which water can pass before flowing over the top edges of the basin 21 to be passed away in a purified state through effluent channels 23. In order to accelerate the sedimentation efficiency in the basin 21, a flocculating agent, for instance a polymer, alum or other salts may be supplied from a stora~e 24 to increase the weight of the organic particles so that they will sink at a greater velocity. The organic matter collected in the bottom portion of the basin is pumped out from the basin 21 by a pump equipment 25, and the pumpable suspension is furnished through a pipe line 26 to a dewatering station 27. At this station the suspension is dewatered, for instance by a pressing and/or centrifuging process, until the accepted stuff, the accept, has a dry substance content of at least 10~ by weight and up to 2~%
dry substance. The high dry substance content now obtained has the advantage that the accept (shown as a block and designated by 28) will be handy, that it can be stacked in a space-saving manner -without any need of particular storage equipments, and that it 20 can be transpor~ed at low cost for further use. -~
.
The material blocks 28 are conveyed in their "dry condition" to a utilization area 29 where it is mixed with water . . ~ .
so as to be spread out together therewith. At the utilization area 29 the blocks 28 may be supplied into a container 30 with ; water in which the blocks 28 readily dissolve. The container 30 i: : .: . .
; is connected through a conduit 31 to a water-carrying conduit 32 of a conventional irrigation plant 33, whereby organic-matter-containing water will be drawn up by ejector action from the ; container 30 and supplied to the stream of water flowing in ~30 conduit 32. The water admixed with organic matter is sprayed _ g _ .
.
: , . - .': ,- ' ' ' ' : ' :
through noæzles 34 over a field 35 and is deposited as a thin film 36 on this field. When this film has dried, it may be continuously tight if the concentration of organic matter is maintained sufficiently high. The film 36 thus formed may be utilized for preventing wind erosion and for preserving h~midity in the underlying soil. It further has soil melioration proper-ties and thus can be used as a soil melioration agent, in which case it is mixed with the organic dry substance in a manner to cause 10 to 20 g dry substance to be spent on each square meter of the field surface. The film also is well adapted to coat sown seeds, particularly when they lie superficially and are especially sensitive during the germination period.
In order to increase the dry substance content of the accept stuff obtained from the separation process, the latter may have dry substance 37 added to it, for instance peat substance from the same peat moor 38 from which the peat fibres, too, have been taken. 5aid dry substance 37 may be added instead of pres-` sing and/or centrifuging or in combination therewith.
-~ Portions of the dewatered accept stuff can be used for producing material for combustion purposes or for lubrication purposes, or as raw materials for chemical industry or as additives in casting.
The separation process described hereinbefore is suitably a sedimentation process, but other methods for separating the organi~c material can also be applied. The different stages and units of the plant illustrated in Figure 3 can be varied within wide llmits without departing from the general scope of the invention.
s, The inventive methodology implies the advantage that not only the peat fibres, but also smaller particles are made use of so that the peat-fibre extraction will only reject roots and other larger components of the peat moor and pure or sub-stantially pure water. These remnant products may be disposed of (for example returned into the peat moor) without any danger ~ - -of interference with the natural environment.
~ .
,; ' .
. - i ... ,............. ~ , - - ': : , - -
Claims (12)
1. A method of producing a peat fiber concentrate com-prising the steps of:
a) measuring the degree of humidification of raw peat on a peat moor;
b) excavating peat from the peat moor;
c) suspending the excavated peat in water;
d) subjecting the peat suspension from step b) to a primary sorting operation wherein oversize material is removed from said suspension;
e) adjusting the peat fiber concentration of the sorted peat suspension from step d) by adding to said suspension an amount of water sufficient to provide a selected peat fiber concentration one percent by weight or less depending upon the initial degree of humidification of the raw peat whereby the consistency of the peat suspension is adjusted to a desired level;
f) providing a screening member having a selected permeability depending upon the adjusted peat fiber concentration of the peat suspension from step e); and g) subjecting the peat suspension from step f) to a secondary sorting operation by passing the suspension through said screening member to produce a concentrated peat fiber suspension and a substantially fiber-free effluent containing colloids and particles less than 0.2 mm in size.
a) measuring the degree of humidification of raw peat on a peat moor;
b) excavating peat from the peat moor;
c) suspending the excavated peat in water;
d) subjecting the peat suspension from step b) to a primary sorting operation wherein oversize material is removed from said suspension;
e) adjusting the peat fiber concentration of the sorted peat suspension from step d) by adding to said suspension an amount of water sufficient to provide a selected peat fiber concentration one percent by weight or less depending upon the initial degree of humidification of the raw peat whereby the consistency of the peat suspension is adjusted to a desired level;
f) providing a screening member having a selected permeability depending upon the adjusted peat fiber concentration of the peat suspension from step e); and g) subjecting the peat suspension from step f) to a secondary sorting operation by passing the suspension through said screening member to produce a concentrated peat fiber suspension and a substantially fiber-free effluent containing colloids and particles less than 0.2 mm in size.
2. A method according to Claim 1, wherein in the primary sorting operation, material greater than about 10 mm in size-is removed from the peat suspension.
3. A method according to claim 1 wherein the initial degree of humidification of the raw peat according to VonPost's scale is from 0 to 3; the amount of water added to the peat suspension after the primary sorting operation is sufficient to adjust the peat fiber concentration to between about 0.75 and about 1 weight percent, and the screen member is selected to have perforations about 1 mm in diameter.
4. A method according to claim 1 wherein the initial degree of humidification of the raw peat according to VonPost's scale is from 3 to 6; the amount of water added to the peat suspension after the primary sorting operation is sufficient to adjust the peat fiber concentration to between about 0.5 and about 0.75 weight percent, and the screen member is selected to have perforations between about 0.5 and about 1 mm in diameter.
5. A method according to claim 1 wherein the initial degree of humidification of the raw peat according to VonPost's scale is greater than 6; the amount of water added to the peat suspension after the primary sorting operation is sufficient to adjust the peat fiber concentration to between about 0.1 to about 0.5 weight percent, and the screen member is selected to have perforations not greater than 0.5 mm in diameter.
6. A method according to claim 1 wherein said secondary sorting operation is effected by passing the suspension under pressure through said screening member.
7. A method according to claim 1 further comprising the steps of:
h) separating organic matter from the substantially fiber-free effluent produced in step g), and i) dewatering the separated organic matter.
h) separating organic matter from the substantially fiber-free effluent produced in step g), and i) dewatering the separated organic matter.
8. A method according to claim 7 wherein the separated organic matter consists essentially of colloids and particles smaller than 0.2 mm.
9. A method according to claim 8 wherein the separation of the organic matter from the effluent is effected in a two stage sedimentation process comprising a first sedimentation stage from which a suspension containing from 4 to 10 weight percent dry substance is obtained and a second sedimentation stage from which a suspension is obtained that after dewatering has a dry substance content of from 12 to 25 weight percent.
10. A method according to claim 9 wherein a flocculating agent is added to said second sedimentation stage to enhance the separation of the organic matter from the effluent.
11. A method according to claim 10 wherein said flocculating agent is a polymeric flocculating agent.
12. A method of treating soil comprising mixing fiber-free organic matter obtained according to any one of claims 6, 7 or 8 with water and spraying the resulting fiber-free aqueous mixture on the soil.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7808215-3 | 1978-07-28 | ||
| SE7808215A SE440792B (en) | 1978-07-28 | 1978-07-28 | SET TO WATCH PURPOSES CONTINUOUSLY AND WITH HIGH YIELD PRODUCING FIBER MASS |
| SE7905855A SE426325B (en) | 1979-07-04 | 1979-07-04 | Process for the preparation of a fibre-free material for use as a soil cover |
| SE7905855-8 | 1979-07-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1103967A true CA1103967A (en) | 1981-06-30 |
Family
ID=26657087
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA332,522A Expired CA1103967A (en) | 1978-07-28 | 1979-07-25 | Method of producing a fibrous mass from peat and means for carrying out the method |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA1103967A (en) |
| DE (1) | DE2930299A1 (en) |
| FI (1) | FI792299A (en) |
| FR (1) | FR2433596A1 (en) |
| NO (1) | NO792439L (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE8107878L (en) * | 1981-12-30 | 1983-07-29 | Hb Torvfiber | PUT TO FRACTION POW |
| RU197206U1 (en) * | 2019-12-25 | 2020-04-13 | Федеральное государственное бюджетное научное учреждение "Федеральный научный агроинженерный центр ВИМ" (ФГБНУ ФНАЦ ВИМ) | Hydromechanical multifunctional peat, biohumus, sapropel cleaner |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE127393C (en) * | ||||
| DE810976C (en) * | 1948-04-29 | 1951-08-16 | Holzspar Ges M B H | Process for the extraction of peat fibers from bog and materials made from it |
| US3603643A (en) * | 1968-12-30 | 1971-09-07 | Mitsui Toatsu Chemicals | Method of separating peat into fibrous substance and humic substance |
-
1979
- 1979-07-23 FI FI792299A patent/FI792299A/en not_active Application Discontinuation
- 1979-07-24 NO NO792439A patent/NO792439L/en unknown
- 1979-07-25 CA CA332,522A patent/CA1103967A/en not_active Expired
- 1979-07-25 FR FR7919198A patent/FR2433596A1/en active Pending
- 1979-07-26 DE DE19792930299 patent/DE2930299A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE2930299A1 (en) | 1980-02-14 |
| FR2433596A1 (en) | 1980-03-14 |
| FI792299A (en) | 1980-01-29 |
| NO792439L (en) | 1980-01-29 |
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