EP0110887A1 - Procede de fractionnement de la tourbe - Google Patents

Procede de fractionnement de la tourbe

Info

Publication number
EP0110887A1
EP0110887A1 EP83900210A EP83900210A EP0110887A1 EP 0110887 A1 EP0110887 A1 EP 0110887A1 EP 83900210 A EP83900210 A EP 83900210A EP 83900210 A EP83900210 A EP 83900210A EP 0110887 A1 EP0110887 A1 EP 0110887A1
Authority
EP
European Patent Office
Prior art keywords
peat
suspension
concentration
passed
fibre
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.)
Withdrawn
Application number
EP83900210A
Other languages
German (de)
English (en)
Inventor
Lars Ake Mansson
Hans Ove Karlsson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HB TORVFIBER
Original Assignee
HB TORVFIBER
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by HB TORVFIBER filed Critical HB TORVFIBER
Publication of EP0110887A1 publication Critical patent/EP0110887A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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

Definitions

  • the present invention relates to a method of fraction ⁇ ing peat in order to make possible an efficient and econom ⁇ ical utilization of one or more of the constituents of the raw peat.
  • a strong flow of water is directed to the peat as it is resting ⁇ in the moss. This brings about a cutting and desintegration of the peat layer, and a washing of the valuable fibres from roots and lumps, and the fibres are held in suspension in the utilized water.
  • the water is preferably directed in such a manner that there is formed a channel which leads to the place where the apparatus is disposed which takes up the water which holds the fibres suspended.
  • This water, which holds the fibres in suspens ⁇ ion forms a material container from which one is permitted to take the material in a suitable way, which material is thus held in a workable condition.
  • a further step is taken by the Swedish patent 45 361 from April 23, 1918, which discloses a method for treating peat by which the raw peat, having been cut up and de- watered, is moved into a basin containing a solution of an agent which has the ability to coagulate blood, such as calcium chloride or iron chloride, and is then moved further on into a rotary sorting apparatus, which sorts out the vegetable fibres which are collected in a collecting apparatus wit the aid of a flushing apparatus. Then, the flowing peat mass is caused to pass through a plurality of similar sorting apparatuses having ever finer meshes, and is subsequently passed into a suitable sorting apparatus wherein impurities are removed. Finally, the peat mass is subjected to washing and drying in air, and a heat drying, whereby a pulverous, agglomerable mass is obtained.
  • an agent which has the ability to coagulate blood such as calcium chloride or iron chloride
  • the patent defines a method of separating water from peat or the like whereby the amount of water is first increased in order to facilitate the separation, which method comprises disperging raw or soaked • peat in such a great amount of water that the solid material does not exceed 2%, then in a first step, separating the solid peat constituents from the gel or mecous constituents and the surplus water by filtering, • • sedimentation, decanting or other methods, without using pressure, preferably continously, and pressing the separated fibre material in a press, which preferably works continuously, and transfering the material into a plurality of thin layers.
  • the peat material suspension should be concentration adjusted in dependence of the initial degree of humidifi- cation of the raw peat, and also that the suspension should be passed to a screening member which should have a perme ⁇ ability which, to ensure a maximum gain from the suspens ⁇ ion, should be dependent on the peat fiber concentration of the suspension after the concentration adjustment.
  • the raw peat is extracted from the moss in any conveni ⁇ ent manner, e.g. by digging or milling, and is placed in a intermediate tank 10.
  • the peat may also be made pumpable alread at the m ss b m so called hydrapulper so that it may be pumped to the intermediate tank 10.
  • this intermediate tank 10 which may also be called a homogenizing vessel, process water is admixed to the peat and the content of the vessel is agitated in a suitable manner so that a comparatively homogeneous suspension having a mean concentration of about 1,5-5 per cent, preferably about 2,0-3,0 per cent is obtained.
  • the mean dwell time of the peat fibre suspension in the intermediate tank should be sufficient to permit particles and objects of higher density than that of the peat suspension itself, particularly gravel, sand and possibly some clays, to sediment to the bottom of the intermediate tank 10 to be removed from time to another.
  • the peat suspension having the said concentration of e.g. 1,5-4% is passed to a coarse screen 11 in which coarser components of the suspension, such as pieces of stumps and roots, are screened off, which pieces in a manner not shown are removed from the process as reject or a so called
  • the necessary process water is fed to the coarse screen through a pipe 12 whereby one can use pure or less pure water, depending on the economic circumstances.
  • the accept. in the shape of a very homogenous suspen- sion having a concentration of e.g. 1,5-4% is passed through a pipe 1 ⁇ to a hole or slot screen 14 of suitable - design wherein the concentration of the suspension is increased to up around the double original value, i.e. to about 3-8% and preferably to the range of about 4,0-6,0%.
  • the accept in question may be moved to a screw or roller press for dewatering to a dryness of about 50%, from which press the accept may be mixed with accept from other presses which will be disclosed below so that a slurry having a concentration of e.g. about 25% is 6b- tained.
  • the screening members of the hole or slot screen 14 have holes or slots dimensioned in dependence of the kind of peat suspension which should be treated and, naturally, also in dependence of the desired concentration of the reject from the screen in question.
  • a hole diameter or a slot width of from about 0,30 to about 1,0 mm and preferably of the order of about 0,5-0,7 is to be preferred at a concentration of 1*5-2,5% on the ingoing suspension and about 4-6% on the outgoing suspension.
  • the just mentioned values may require a slight variation in adaptation to the actual conditions, such as the degree of humidification of the treated peat.
  • the screen may be pressure-fed and of the open or closed type depending 'on the requirements as to capacity and/or field of use of the screen in question.
  • the releasing of the reject, i.e. the fibre rich suspension, from the screening member for transport further on, both with the hole or slot screen 14 and with other screens that will be disclosed further below, may be promoted by addition of a certain amount of spray water which then, to reduce the water volume, is preferably admitted only intermittently, under certain conditions it may be found to prefer to use compressed air or a brush for the same purpose.
  • the fibre rich sus ⁇ pension having a fibre concentration of the order of e.g. 4-6% is passed through a pipe 15 to a dehydration means, generally denoted 16.
  • This dehydration means may consist of a known centrifuge, which is normally able to thicken the suspension to such an extent that the resulting pulp has a fibre concentration or dryness of the order of about 15-20%, which can oftentimes be regarded as sufficient if the pulp is to be used comparatively immediately and must not be stored for an extended period or transported longer distances.
  • the dehydration means 16 may also consist of a screw press or a so called screen band press, by means of which a dryness of the order of 30% may be obtained with no difficulties.
  • the fibre poor accept from the hole or slot screen 14 is passsed through a pipe 17 to one or more fine screens, in the present case two parallel coupled fine screens 18, 19, which may be provided with screen clothes having a mesh of 30-500 urn, preferably 80-100 urn.
  • the chosen mesh of the screen clothes of the fine screens is very important for the result which may be achieved in the subsequent process step, viz. in that a significant flocculation to bring about a sedimentation or flotation can only be secured at a comparatively high degree of screening in the fine screen or screens, e.g. so that there is a dry substance concentration of about 0.7 per cent by weight, as a maximum.
  • the relative fibre richer reject from the fine screens 18, 19 has a concentration of about 10-20%, normally about 1,5%.
  • the fibre poor accept which nearly has the character of a somewhat impure water, is preferably passed to a vessel 20 from where it is taken to suitable points to serve as process water.
  • the relatively fibre richer reject from the fine screens 18, 19 is in the present case passed through a pipe 21 to a dehydration means, generally denoted 22, which may consist of a known screen band press, a centrifuge or the like.
  • this suspension is preferably admixed with some quantity of an additive, preferably a polymer, where the kind of polymer and the necessary amount thereof are dependent on the actual conditions, particularly the acidity and the concentration of the suspension.
  • the dehydrated pulp obtained from the dehydration means 22 is very dark colored, and differs to its consistency entirely from the light, fibre rich pulp which is obtained from the dehydra- tion means 16 (fraction I) .
  • the dark colored pulp (fraction II) from the dehydration means 22 has a rather high heat value, viz.
  • the fraction II is extremely well suited to be utilized as fuel in various connections. Further, it has a number of advantageous properties in connection with its use as fuel, e.g. in that the ash content is normally comparatively small.
  • the just mentioned values may vary from one moss to another and vary with the degree of humification.
  • a not insignificant flow of a next to entirely fibre free suspension which through a pipe 23 is passed to a separator, generally denoted 24, which may consist of a sedimentation or flotation means.
  • the separation is contemplated to be a sedimentation means, preferably in the shape of a known so called lamella sedimentation means.
  • the suspension is admixed with suitable additives to promote the agglomeration of the agglomerable constinuents into sedimentable flocks.
  • suitable additives are, for instance, iron chloride, which may be
  • agent which agent may be added in such a small amount as about 4-8 g/m 3 of the suspension, preferably about 6 g/m3.
  • the "clear" phase is passed througn a. pipe 25, 26 to the vessel 20 to be returned to the process as process water, or is the "clear" phase passed back to the recipient through the pipe 25, 27.
  • the "clear" phase from the sedimentation means has been found so free from impurities that the amount of dry substance has been less than between 10 and 100 mg/1 of the liquid in 0MPI analysis of the clear water has given the following values, viz. :
  • the flocks sedimented in the sedimentation means are passed, in the lowermost portion of the sedimentation means, to a thickener, generally denoted 28, wherein a thickening of the suspension to a dry substance content of the order of 2,5-7, preferably 5-6 per cent by weight is carried out.
  • This thickened suspension is then passed to a dehydration means of suitable' esign, e.g. in the shape of a press or a centrifuge, from which an extremely black mass having a dry substance content of 15-25 per cent by weight is obtained.
  • this mass has such a high heat value as of the order of about 28,9 MJ/kg and is useful per se to be utilized as fuel, and may be used for other purposes in that the properties of the mass.
  • the mass can also advanta ⁇ geously be mixed with the above mentioned peat fraction O and II in a suitable mixer.
  • a calculation of existing flows, and gains, i.e. establishing a flow balance reveals that, apart from plant residues and stones, gravel, sand and possible clays, close to all the solid material within the moss is gained in one or another fraction whereas that which is returned to the moss is only entirely pure water.
  • a certain heating of the suspension e.g. to about 60°C but not above 100°C facilitates the dehydration and permits an all around the year extraction.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Paper (AREA)
  • Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Abstract

Procédé de fractionnement de la tourbe dans lequel de la tourbe brute est extraite d'une tourbière d'une façon appropriée et est envoyée à un récipient d'homogénéisation dans lequel la tourbe est mélangée à de l'eau de traitement et est agitée de manière à obtenir une suspension homogène possédant une concentration moyenne d'environ 1,5-5,0 %. Après l'homogénéisation la suspension de tourbe traverse un tamis à mailles grossières, où les composants grossiers sont enlevés, et d'ici, la suspension, présentant une concentration de 1,5-4,0 %, traverse un tamis à trous ou à fentes où la concentration est augmentée jusqu'à environ 3,0-6,0 % en poids. Le produit provenant du tamis à trous ou à fentes est ensuite envoyé à un organe de déshydratation où il est déshydraté jusqu'à obtenir une teneur en substances sèches de l'ordre de 15-20 %, ou de l'ordre d'environ 30 % si l'organe de déshydratation est une vis ou une tresse à bande de tamis ou analogue. La faible quantité de fibres provenant du tamis à trous ou à fentes est envoyée de préférence à un tamis à mailles fines permettant d'obtenir un produit présentant une teneur maximum en substances sèches de l'ordre d'environ 0,7 % en poids.
EP83900210A 1981-12-30 1982-12-30 Procede de fractionnement de la tourbe Withdrawn EP0110887A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8107878A SE8107878L (sv) 1981-12-30 1981-12-30 Sett att fraktionera torv
SE8107878 1981-12-30

Publications (1)

Publication Number Publication Date
EP0110887A1 true EP0110887A1 (fr) 1984-06-20

Family

ID=20345407

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83900210A Withdrawn EP0110887A1 (fr) 1981-12-30 1982-12-30 Procede de fractionnement de la tourbe

Country Status (5)

Country Link
EP (1) EP0110887A1 (fr)
FI (1) FI840372A0 (fr)
NO (1) NO833099L (fr)
SE (1) SE8107878L (fr)
WO (1) WO1983002284A1 (fr)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3603643A (en) * 1968-12-30 1971-09-07 Mitsui Toatsu Chemicals Method of separating peat into fibrous substance and humic substance
GB1399508A (en) * 1972-08-08 1975-07-02 Recognition Devices Ultrasonic tracking and locating systems
FI792299A7 (fi) * 1978-07-28 1981-01-01 Evald Gottfried Schmidt Tapa valmistaa kuitumassaa turpeesta ja laite tavan soveltamiseksi.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8302284A1 *

Also Published As

Publication number Publication date
FI840372A7 (fi) 1984-01-30
SE8107878L (sv) 1983-07-29
WO1983002284A1 (fr) 1983-07-07
FI840372A0 (fi) 1984-01-30
NO833099L (no) 1983-08-29

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Inventor name: KARLSSON, HANS OVE

Inventor name: MANSSON, LARS AKE