METHOD AND APPARATUS FOR MANUFACTURING FIBER PULP

Abstract: A refiner for manufacturing fiber pulp from lignocellulose-containing material, comprising a pressure-proof refiner housing (20) with opposed refining members (21, 22) rotating relative to each other. Steam is separated from the fiber pulp in the refiner housing (20) at the counter-effect of a fiber separating rotor (30) provided with wing members (31) and located on the rear side of a rotatable refining member (22). The steam is thereafter compressed in at least one step by means of this rotor (30) and possibly subsequent turbine wheels (34).

Description: ethod and apparatus for manufacturing fibre pulp This invention relates to a method and an apparatus for entirely or partially recovering supplied heat and electric energy at the manufacture of fibre pulp from lignocellulose-containing material, such as chips from softwood or hardwood, bamboo, straw, bagasse etc. The invention comprises mechanical disintegration of chemically processed or unprocessed material at increased temperature to fibre state in a refiner. The refiner comprises at least two opposed refining members rotary relative to each other and enclosed in a pressure-proof refiner housing and having refining surfaces, which are plane, conic, spherical or a combination thereof. The opposed refining members, thus, can be rotatable in opposite directions or one member may be rotatable and the other one stationary. The mechanical disintegration of the material is effected in that the material is supplied to the inlet opening of the refining members and successively discharged from there through an adjustable gap maintained between the. refining members. - This disinetration or refining of the material requires, depending on the type of fibre pulp manufactured, a varying amount of electric and steam energy (50 - 3500 kWh/ton ), usually at a processing temperature of 100-250 C. The fibre pulp manufactured at the disintegration and the steam generated or supplied can be separated, according to a method described previously in Swedish patent applic¬ ation No. 8300961-3, .already in the.-refiner housing operating under pressure, where fibre pulp and steam separately are discharged from the refiner individ- uaiiy. The separation of steam and fibres is effected in that steam generated at the process or supplied is forced by the steam pressure generated at the process to pass from the space outside the periphery of the refining members against the effect of the centrifugal force inward on the rear side of a rotatable refining member. This refining member, therefore, is provided with wing members preventing the fibre pulp from flowing inward. At this passage through the wing members the steam amount going off from the process and the fibres thereby suspended and following along are caused to assume a rotation speed corresponding to that of the refining member and thereby are subjected to a centri gating cleaning. By the effect of the centrifugal force the fibres and particles following along with the steam are returned to the fibre outlet of the refiner, and at the same time the cleaned steam is discharged separately from the refiner housing for further use. The aa±d steam thus discharged, by being fed in radial direction to the rotation centre against the effect of the centrifugal force, s subjected to a small pressure reduction. Therefore,- a sealing " device is required -to - - prevent frterse passage between the periphery of the wing members and the space outside said members where the cleaned steam is collected for being discharged. This sealing requirement is eliminated according to the invention, at the same time as the high rotation speed of the refining member is utilized for bringing about by one or several compression steps an increase in the pressure of the discharged steam. The present invention, thus, renders it possible that the steam amount discharged from the process is transferred to a higher energy level OMPI by means of turbine wheels in connection to the rotor or axle of the refiner. The pressure can be increased to a level, which renders it possible to use the steam for more qualified application fields, papermaking machines, . drying plants etc. Such installations usually require a steam pressure higher than normally permissible at the fibre manufacturing process. The characterizing features of the invention become apparent from the attached claims. An embodiment of the invention is described in greater detail in the following, with reference to the accompanying Figure, which is a schematic section of a refiner applicable in the process and provided with fibre separating rotor and with steam pressure increasing turbine wheels directly connected thereto. The refiner shown in the Figure comprises a pressure-proof refiner housing 20 and a feed-in conveyor 10 with a conveyor screw 11 for feeding the material to refining members 21 and 22 enclosed in the refiner housing 20. At the embodiment shown, the refining member 21 is stationary in respect' of rotation, but axially movable for adjusting the distance between the refining members. This adjustment is effected by adjusting means 27, which are controlled simultaneously by a control member 28 via a drive chain ' 29 surrounding all adjusting means 27. The refining member 22 is rotary and connected to a rotor 2-4. The rotor 2k is supported on an axially fixed drive axle 25 3 which is sealed by a sealing.-device 26 at the entrance in the refiner, housing 20 operating under pressure. The material processed in the refiner is collected in the space ~ -. in the refiner housing 20 outside the refining members together with generated or supplied steam. The processed refiner produce is transferred by one or several dogs 52 connected circumferentially to the rotor 2 through an opening 23 in the refiner housing 20 to a pressure-proof connected discharge device 50, which does not permit steam passage. The fibre pulp thereby is discharged without or only with a small amount of steam following along. The rotor 2- is provided on its rear side with a fibre- -separating rotor 30 comprising wing members 31 , which between themselves form passageways extending first substantially radially inward and thereafter substantially radially outward to an annular space 37. The passageways preferably open into the space 37 on a greater diameter than the inlet from the space 5 . The steam amount generated at or supplied to the process is forced by the steam pressure generated in the process in the space 5 to flow in radial direction inward to the rotation centre through the separating rotor 30, where the steam and fibres and particles following along are caused to assume a rotation speed corresponding to that of the refining member 22 and there are subjected to a centrifugating cleaning. By means of the centrifugal force generated at the rotation, the fibres and solid particles are returned to the space ~ -\ outside the refining members 21,22 while the cleaned steam is transferred to said annular space 37- At the embodiment shown, a s ' econd annular space 38 is located after the first annular space 37. These spaces inter¬ communicate through stationary guide bars 32, which are capable to pass the steam inward from the first space 37, and a turbine wheel 3 rotating together with the refining member 22, which turbine wheel is capable to pass the steam with increased pressure outward to the second space 38 The steam pressure in the annular space 37 at the outlet of the steam from the separating rotor 30 with its greater diameter and efficiently designed wing members 31 is higher than the steam pressure in the space 54. This eliminates according to the invention the risk of leakage of fibre fragments and other solid particles from the refiner housing 20 to the space 37 for the cleaned steam. The compressed steam leaving the turbine wheel 3 is collected in the second annular space 38. The steam is discharged from there through an outlet 39 and a control valv-e 44 located there, by which valve the pressure in the refiner is controlled. At the embodiment shown this control is effected by means of a pressure sensing member 42 and an adjusting member 40, which controls the valve 44, so that the desired pressure can be maintained in the space 5 outside the refining members 21,22. The invention can be varied within wide limits, in respect of number, diameters and type of compression steps. The pressure increasing part, thus, can be separated from the refining member 22 and fibre separating rotor 30 there attached and be placed in a space separated from the refiner housing, -driven directly or indirectly from the axle 25 carrying the refining member 22. The pressure increasing turbine also can be provided with intake for steam drained at other places in the process, for example at the inlet to the refining members. The pressure increasing means also can be divided into diff¬ erent groups of turbine wheels with a different number of steps for increasing the pressure of steam from different take-offs with different pressure to a common higher level. The invention is not restricted, either, to the embodiments set forth, but can be varied additionally within the scope of the invention idea. OMPI

Claims: Claims 6 1. A method for entirely or partially recovering steam, which is supplied or generated in a process for manufacturing fibre pulp from lignocellulose-containing material in a refiner comprising at least two opposed refining members rotatable relative to each other and enclosed in a pressure-proof refiner housing, at which method the material is disintegrated while passing outward through a gap between the refining members and thereafter is discharged out of the refiner housing, c h a r a c t e r i z e d i n that steam is separated from the fibre pulp in the refiner housing at the countereffect of centrifugal forces generated by rotation of at least one refining member, that the steam thereafter is compressed by help of the rotation of the refining member, so that the steam is discharged from the refiner at a pressure higher than the pressure prevailing in the refiner housing immediately outside the gap. 2. A method as defined in claim 1, c h a r a c t e r i z e d i n that the steam is compressed in several steps on its way out of the refiner housing. 3. An apparatus for entirely or partially recovering steam, which is supplied or generated in a process for manufacturing fibre pulp from lignocellulose-containing material, comprising at least two opposed re¬ fining members (21, 22) rotatable relative to each other and enclosed in a pressure-proof refiner housing (20), which refining members (21, 22) between themselves form at least one gap, in which the lignocellulose- containing material is intended to be disintegrated to fibre- pulp, c h a r a c t e r i z e d i n that behind a rotatable refining mem¬ ber (22) wing members (31) are located and rotatable together with the re¬ fining member (22), that the wing members (31) between themselves form passageways, which extend first substantially radially inward and there¬ after substantially radially outward to an annular space (37), and that this space (37) communicates with an outlet (39) for steam. 4. An apparatus as defined in claim 3, c h a r a c t e r i z e d i n that the passageways between the wing members (31) open into the annular space (37) at a greater distance from the rotation centre than the opening of the passageways to the refiner housing (20). 5. An apparatus as defined in claims " 3 or 4, c h a r a c t e r i z e d i n that at least one additional annular space (38) is located after the first annular space (37), and the spaces (37, 38) intercommu¬ nicate through stationary guide bars (32) capable to pass the steam inward, and a turbine wheel (34) rotating together with the rotatable refining member (22), which turbine wheel is capable to pass the steam with increased pressure outward. 6. An apparatus as defined in any one of the claims 3 - 5, c h a r a c t e r i z e d i n. that control means (40) are provided to adjust the pressure in the refiner housing (20) by means of a pressure sensing member (42) in the refiner housing (20) and a valve (44) in the steam outlet (39), OMPI

Inventors: JOHANSSON JOHAN GUNNAR INGE, REINHALL ROLF BERTIL, JOHANSSON, JOHAN, GUNNAR, INGE, REINHALL, ROLF, BERTIL
Applicants: SUNDS DEFIBRATOR, SUNDS DEFIBRATOR AKTIEBOLAG
Application year: 1984
Main classification: D21B1
IPC codes: D21B1, D21D1