FI67102B - SAETT OCH ANORDNING VID DEFIBRERING - Google Patents

Description

M ^ ANNOUNCEMENT, π.λλ

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Pxarti och tegisterstyralsaM '' AmMcm ad * d odt wcUfcrift · * pmUtcmnd 28.09.84 (32K33M31) nryd ^ Fierfc * 21.04.78 Sweden-Sweden (SE) 7804602-6 (71) AB Bahco Ventilation, S — 199 01 Enköping, Sweden -Sverige (SE) (72) Agne Torvald Mattsson, Enköping, Sweden-Sverige (SE) (74) Oy Hei nänen Ab (54) Method and device in defibering - Sätt och anordning vid defibrering

The invention relates to a method for transporting a chipped pulp from a fiberizer to a separator to separate the pulp and steam when defibering the chips in steam. The invention also relates to a device for carrying out this method.

To transport the pulp from the fiberizer to the separator, it is common to utilize a somewhat significant overpressure of steam in the fiberizer, often 0.5-1 MPa, allowing the steam to expand to ambient pressure and not infrequently allowing it to flow into the ambient air after transport, resulting in significant energy loss. Although in some cases the steam is recovered after the separator, due to its reduced pressure and reduced temperature, it constitutes a less valuable source of energy than the steam in the fiberizer.

It is an object of the present invention to provide a method and apparatus for conveying pulp between a fiberizer and a separator, which method and apparatus make it possible to recover all excess steam at high pressure and high temperature.

The desired result is achieved by giving the method and the device in question the features which appear from claim 1 and claim 2, respectively.

'67102

The invention will be described in more detail below with reference to the installation diagram shown in the accompanying drawing.

The raw chips, which may possibly be somewhat preheated, are fed to a screw feeder 1 which compresses the chips into the preheater 3 of the defiberist 2. A fresh steam supply line 4 is connected to the preheater 3 to heat the chips at least at the beginning of the defibering process. The chips heated to the defibering temperature are fed to the fiberizer 2 by means of a second screw feeder 5. The pulp produced in the defibrator is taken out together with the steam supplied and produced in the defibrator by means of an ejector 6, the suction side 7 of which is connected to the fiberizer outlet 8.

The operating flow of the ejector is formed by steam and the combined flows leaving through the ejector outlet 9 thus consist of pulp and steam which the ejector carries to a separator 10, to the inlet 11 of which the ejector outlet 9 is connected by a pipeline. The separator consists of two cyclones 12 connected in series.

The mass separated from the steam in the cyclones 12 is taken out for use in a conventional manner via outlet devices such that they seal the outlets 13 of the cyclones so that the cyclones can be pressurized.

The steam released from the pulp is taken out of the gas outlet 14 of the last cyclone 12 and passed through a line to the suction side of the fan 15, the pressure side of which is connected via a second line to the operating flow inlet 16 of the ejector 6.

The ejector 6, the separator 10 and the fan 15 thus belong to a circulating system in a closed system, in which the separator is also pressurized to the same order of magnitude as the pressure prevailing in the fiberizer. The operating flow of the ejector is formed by steam separated from the pulp and taken out of the separator 10 and raised to the required pressure in the fan 15. The supply of fresh steam through line 4 can be varied, usually reduced after the start-up phase and the steam addition to preheater 3 is circulated. The grinding energy produces additional steam from the moisture of the chips in the fiberizer, which can be taken out at high pressure and high temperature via the second line 18 due to the pressure of the whole system, as a result of which the device according to the invention can also serve as an energy source for many purposes.

Claims (2)

3 67102 A method of fiberizing wood chips in steam to transport the prepared fibrous pulp from the fiberizer (2) to a separator (10) for separating pulp and steam, characterized in that the steam stream separated from the pulp is taken out of the separator (10) and pressurized and forced to an ejector (6). the ejector is used to extract the mass and steam flow from the fiberizer and both said combined flows in the ejector are passed to a separator (10) which is kept pressurized by steam to isolate it from the outside air, while limited excess steam is returned to the fiberizer (2) as an energy source for other purposes. Apparatus for carrying out the method according to claim 1, comprising a conduit connection between the defiberizer (2) and the separator (10), the latter being arranged to separate the pulp and steam received from the defiberer, characterized by a pressure-increasing steam conveying member (15), for example a fan with a pressure-boosting member. is connected to the steam outlet (14) of the separator (10) and on the other hand to the ejector (6), the pressure side of the pressure-raising member (15) being connected to the operating medium inlet (16) in the ejector (6), while the inlet (7) in the ejector is connected to the pulp and steam outlet (8) in the fiberizer (2), and the ejector outlet (9) is connected to the inlet (11) of the separator (10), in addition to the pressure boosting member (15), the ejector (6) separator (10) and the connecting lines. -circuit forms a closed system in which the separator (10) also remains pressurized by steam by suitably draining the excess ä-steam, which is returned to the chip preheater (3) of the fiberizer (2) and / or used as an energy source for other purposes.