CN1094414C - Method and arrangment for the continuous production of lignocellulose-containing boards - Google Patents

Abstract

The present invention relates to a method and to an arrangement for the continuous production of lignocellulosic boards, wherein material is disintegrated into particles and/or fibres, glued, dried and formed into a mat (1). The mat is pressed in a continuous steam-injection press (2) into board form (3) and then passed through an after-conditioning unit (4). Gaseous emissions and steam occurrent in the press process are captured. Hot air is supplied to prevent condensation of the gaseous emissions and the steam when leakage air from the surroundings is admixed therewith and also to transport the steam and emissions to a combustion plant for combustion.

Description

Produce the method and apparatus of the plate of lignocellulose-containing continuously

The present invention relates to a kind of as claimed in claim 1 as described in the preamble, be used for producing continuously the method for the plate that contains lignocellulosic and the device that is used for implementing this method.

Using raw material based on lignocellulosic to come the method for making sheet is being well-known in the art, and widely-used in practice.The method of making this plate comprises following key step: raw material are resolved into fiber and/or have the particle of appropriate size; With particle and/or the predetermined humidity ratio of fiber drying to; And before or after described drying process, carry out gluing to described material; Making gluing material forming is a cushion block, and which floor described cushion block can comprise; And optional, described cushion block is carried out cold prepressing, described cushion block is preheated, water sprays cushion block surface etc., and in a discontinuous press or a continuous press, described cushion block is carried out hot pressing, simultaneously pressure and heat are acted on described material, thereby can obtain a production board.

No matter be to adopt continuous press or adopt discontinuous press, present manufacturing technology has a well-known problem,, in the pressing process of carrying out with high temperature, can produce gas in press that is.These gases comprise steam (steam), decompose the different volatile materials that come out from timber and glue is so-called VOC (VOC), and the gaseous state phenol etc. that comes from timber and glue.People find that long term exposure can cause stimulation in these materials, and when the concentration of these materials is higher, also are harmful to health.Therefore, the administrative authority that much utilizes preceding method to make the country of plate has worked out series of rules and regulations, has stipulated emanation concentration that is allowed in the workplace and the permissible concentration that allows to be dispersed into the emanation in the atmosphere.

Because comprising, present compact technique adopts even heating plate or steel plate, therefore, the gas that produces in compacting has only a very little part can pass the edge of each plate in press process and leave each plate, and the major part of these gases is all just left plate when plate leaves press.Though since the size of press more greatly thereby the air that normally will be in room temperature as transporting air,, these gases can be with the use of protecting sheathing and cover cap for the influence of working environment and restriction to some extent.Therefore, this air volume usually will be above the requirement of the combustion air in the standard firing equipment of factory.Most of like this complicated and expensive equipment of the just essential installation of device of producing wood fibre cellulose sheet and plate.For example, described equipment generally includes and is used for purifying the compacting so-called RTO of gas (regenerated heat oxidant) device or air-washing system.

The object of the present invention is to provide a kind of method and apparatus that is used for producing lignocellulosic board, it can not arrive relevant zone, workshop and surrounding environment with VOC or formaldehyde emission, and no longer needs to install expensive cleaning equipment.This purpose can be realized by the inventive method and the device that have as the listed characteristic feature of each claim.

Below in conjunction with accompanying drawing the present invention is more specifically described, this accompanying drawing is vertical cross-sectional schematic of apparatus of the present invention.

Equipment shown in the drawings is that these two patents have been described two kinds of continuous steam pressing process based on the equipment that is disclosed in Swedish patent 502 272 and the Swedish patent 504 638.In a continuous vapor injection press 2 to one in manufacture process preformed fiber mat 1 suppress to form a plate or sheet material 3, make then its pass one the back humidity control device 4.When fiber mat 1 enters two roll gaps between the vapor injection roller 5, steam is carried and injected in the fiber mat by wire rod 6.Temperature very rapidly rises to more than 100 ℃; Usually this temperature is more than 120 ℃.Thus fiber mat is made a kind of solid slab.When described solid slab left roll gap between the vapor injection roller 5, pressure descended, and temperature also very rapidly falls to about 100 ℃ down thereupon.This is owing to evaporating rapidly of moisture of part sealing taken place.VOC emanation and formaldehyde emission thing are accompanied by this steam that leaves.

Because this process is can see through between the wire rod 6 of gas at two to take place, therefore, steam and can pass its whole width with the gas that steam leaves and leave described plate.Steam and gas emanation are hunted down by an aspirator 8 that is arranged on this end of described press inside before entering in zone, workshop or the ambient atmosphere escaping.Temperature is heated the air that surpasses 100 ℃ and is transported to this aspirator.Hot-air is with the carrier gas of those leakage air that leak out from surrounding environment as steam and gas emanation.Hot-air, leakage air, steam and emanation are transported to firing equipment 9 in the factory to burn.Maintenance district 10 in one hot-air conveying device 11 and the press 2 links to each other, and makes the hot-air of being supplied enter aspirator 8 then.

Temperature is remained on the purpose of a higher temperature, is in order to prevent that emanation and steam are condensed to suction system on the one hand, is to increase this fact for the ability (calculating with every kg air) of utilizing air to carry moisture raises with temperature on the other hand.So just can make total air volume and gas volume remain on the value of the factory system that can not be above standard combustion air volume of needed heat and steam when producing this sheet material.Therefore, do not need to install miscellaneous equipment and prevent that emanation is distributed in the surrounding environment.

After in continuous vapor injection press 2, producing described plate, described plate is conveyed in the back humidity control device 4 (referring to Swedish patent 504 638), at this place, see through described plate, those air that have been heated to predetermined temperature and had a predetermined volume of predetermined moisture are aspirated, to obtain desirable sheet material moisture and temperature.The air that leaves the back humidity control device also will contain the emanation of VOC and formaldehyde, but negligible amounts; The measured value that obtains in pilot plant shows that most emanation occurs in the continuous vapor injection press.For this reason, an aspirator 12 is arranged in the humidity control device 4 of back.At 13 places air is aspirated, and heat, then by pipeline 15 supply steam with heater 4.

The air that will leave the back humidity control device with a sucktion fan 16 is transported to hot-air feeding mechanism 11 and its maintenance district 10 of vapor injection press 2.When it enters feeding mechanism 11, give air with additional-energy by the effect of a heat exchanger 17.If from the air excess of back humidity control device 4, excess air is mixed mutually with air-flow from press 2 in an enclosed-ventilated cabinet 18, be sent to firing equipment 9 then.If flow to the lack of air in maintenance district 10, sucktion fan 16 can suck extra air by enclosed-ventilated cabinet 18.Like this, just can the hot input air of the air of back humidity control device 4 as the interior aspirator 8 of continuous vapor injection press will be left.Measurement shows: these volumes are enough to reach the needed necessary transportation volume of continuous vapor injection press.

After by back humidity control device 4, can also randomly plate 3 be transmitted by surface sclerosis press (do not give in the accompanying drawings and illustrating) according to Swedish patent 502272.This surface sclerosis press also comprises a special aspirator, and it can be transported to those combustion apparatus of factory under the help of hot-air emanation is captured in the described press to produce heat and steam.

Claims (6)

1. one kind is used for producing continuously the method for lignocellulosic board, wherein, elder generation is ground into particle with material and/or resolves into the form of fiber, gluing, drying and formation cushion block (1), described cushion block is pressed into the form (3) of plate in a continuous vapor injection press (2), then described plate is transmitted by a back humidity control device (4), it is characterized in that, be captured in the steam and the gaseous state emanation that produce in the pressing process, and hot-air is supplied to described process, prevent gaseous state emanation and described steam generation condensation when mixing mutually with the leakage air that comes from surrounding environment with steam with the described emanation of box lunch, and prevent leakage air generation condensation, and emanation is transported to a combustion apparatus (9) burns from surrounding environment.

2. the method for claim 1 is characterized in that, supplies hot-air and the leakage air that comes from surrounding environment with the supply that equals the required combustion air amount of firing equipment (9) at most.

3. method as claimed in claim 1 or 2 is characterized in that, the air that temperature is surpassed 100 ℃ is supplied to the interior maintenance district (10) of press (2).

4. as the described method of arbitrary claim in the claim 1 to 3, it is characterized in that, energy is supplied to the suction air that comes from back humidity control device (4), thereby make temperature surpass 100 ℃, the delivery air that the emanation that this air is used opposes then comes from vapor injection press (2) transports.

5. be used for implementing device as method as described in arbitrary claim in the claim 1 to 4, described device comprises a continuous vapor injection press (2) and a back humidity control device (4), it is characterized in that, one aspirator (8) is arranged in the vapor injection press (2), catch gaseous state emanation and steam, then described emanation and steam are transported to a combustion apparatus (9), and are used for hot-air is supplied to the device (11) of aspirator (8).

6. device as claimed in claim 5 is characterized in that, hot-air feeding mechanism (11) links to each other with a aspirator (12) in back humidity control device (4) supplying air, and a heater (17) links to each other with the pipeline that transports between the described device.