DE102006024034A1 - Production of mixed, recycled fiber suspension for papermaking machine, employs sufficient stages to maximize fibrous content in waste portion used for thermal and electrical energy generation - Google Patents

Abstract

The number of suspension preparation stages selected, is sufficient to generate a given waste portion (5) at their end. This portion has a fibrous content exceeding that which would be generated by an even larger number of stages. The waste portion (5) is devoted to thermal- or electrical energy generation. This energy is partially or entirely supplied: for production of fibrous mixture, to the papermaking machine (14) or to a connected paper finishing plant. A flotation plant (12) is used. The method produces graphic- or packing paper. The portion used for energy production (5) has a fiber content exceeding 8%, 20%, 30% or 50%. At most, only a single stage is used in the sorting plant (10), cleaning plant (11), flotation plant (12) or washing plant. From the waste portion (5) used to produce energy, a fuel is obtained using a biogas plant (13). The fuel recovered is hydrogen, hydrocarbons, methane, alcohols or methanol. It is oxidized or burned to produce thermal and/or electrical energy. Further biological waste is added to the waste portion (5). At least some heat obtained from combustion, is sent to one or more processing stages, the papermaking machine (14) and/or to paper finishing. The fuel may be used in a fuel cell, to produce electrical energy and/or process heat. Heat arising from combustion is converted at least in part, into electrical energy. This is supplied to one or more processing stages, the papermaking machine and/or to paper finishing stages.

Description

The The invention relates to a method for producing a fiber mixture for one Paper machine from a raw material for paper production, in particular from a waste paper mixture.

The Generation of a fiber mixture for a paper machine has been perfected over the decades so it's possible nowadays is, almost all Fibers from a raw material for paper production, in particular from a waste paper pile, sever and a paper machine supply. For this purpose, the stock preparation is very elaborately designed, and a Variety of treatment stages with similar treatment plants, such as sorting plants, cleaner plants, flotation plants and car washes are switched one behind the other, in order to still the "last remainder" of the fibers from the To extract raw material and feed it to the paper machine. sorting and washing systems work with sieves, flotation systems with foaming for the separation of fine substances and cleaner systems with hydrocyclones. The series connection in several preparation stages means in this context, that in a first preparation stage the raw material is passed, for example, through a flotation plant, which divides this raw material into two parts, namely the so-called Acceptance and the reject, the latter under the present Invention is generally referred to as waste content. This one will in a second stage by a second treatment plant mostly of the same type, in the example mentioned again a flotation plant, reprocessed, so that from the waste content again a share of acceptances which is usually obtained with the accepts of the first preparation stage together and can be supplied together to the paper machine. The waste content the second stage can in other downstream treatment stages again be subjected to the same or a different treatment, so as to extract the fibers still contained and as accepts also to feed the paper machine.

today Processing plants with a variety of treatment stages enable Thus, that the waste content of the last stage a pulp content of less than 5%, because the remaining fibers as accept previously through the advanced processing technology from the raw material were extracted.

The publication DE 10 2004 006 516 A1 proposes to use the waste generated during the production and / or refining of a fibrous web for the production of process heat and / or electrical energy by generating a gas with the highest possible hydrogen content from the resulting waste products.

Consequently So far one could assume that the utilization of the raw material for paper production is considered optimal, at least as long as until further technical developments allow even more fibers Extract the existing raw material so that the waste content even less fiber is.

Of the Invention is based on the object, a method for generating a fiber mixture for a paper machine from a raw material for paper production, in particular from a pile of paper, to represent, which at least from economic point of view the known method is improved and at the same time the supplied raw material in terms of saving natural resources completely or largely in stock preparation, in paper production the paper machine and / or a subsequent paper finishing uses.

The inventive task is achieved by a method having the features of claim 1. The dependent claims describe advantageous and particularly expedient embodiments of the invention.

The Invention is based on the recognition that the technical development Although in the last decades to a maximum pulp yield the supplied Raw material for paper production led has, however, the technical and financial effort for this Maximization is now considerable, and especially the cost to extract the last recoverable Fibrous content from the waste content behind several treatment stages increase exponentially. Here, pulp is the entirety understood the organic pulp, ie long fibers, short fibers and fiber fines (fiber fragments).

The The invention therefore provides for the processed fraction of the raw material to reduce paper production compared to the known methods and so that the non-processed share, that is to increase the proportion of waste, and this did not increase processed portion for generating thermal and / or electrical To use energy, which in turn is used in one of the treatment stages, used the paper machine and / or a subsequent paper finishing becomes.

Thus, compared to the current state of the art, the invention initially takes a step backwards as far as the technical possible extraction of fiber material from the raw material for paper production is concerned, and deliberately does not use the technical possibilities for the "last" fiber content Extract the raw material and only use the remaining amount of waste to generate energy. The proportion of fibers that can no longer be recovered in production plants depends on the raw material and quality requirements. For example, a newsprint paper production using flotation has a fiber loss of about 3 to 7% and in the production of tissue paper about 10 to 20% based on the solid in the feed suspension. In contrast, a waste fraction is specifically formed with the new method, which in comparison to the prior art has a significantly higher fiber content, in particular of more than 8%, in special cases up to 50%.

at A cleaner or a sorting system are the fiber losses significantly smaller than in flotation. They are lying (every facility considered individually) at about 1% or below. Because such investments are often time-consuming and can also be found here with a project-related multi-level structure the new process economic Achieve improvements.

Of the Waste content is used to generate thermal and / or electrical Used energy, which then, in particular directly or indirectly, one or more stages of preparation, the paper machine or a subsequent Paper refining supplied and used there. The raised Proportion of organic matter in waste improves its calorific value.

The In fact, inventors have realized that it makes more economic sense to last To abandon percentage points of a yield of the raw material and instead the resulting (in comparison to the prior art larger) biomass to utilize the waste content thermally, even if they are still recoverable fibers contains. This is particularly well possible in the context of paper production because there just thermal energy, for example, to dry the paper anyway needed will, and this the energy used from the thermal utilization of the waste component can be.

One Another advantage of the solution according to the invention is that in the subsequent papermaking process the more suitable fibers of the raw material used for paper production can be. Depending on the type of treatment process is in succession following treatment stages not only the actual waste is concentrated, but in the contained fiber material often a certain Fiber type. Thus, for example, in the reject of flotation plants increased Proportion of short fibers and fiber fines for certain paper strengths unfavorable are. Also, the frequent treatment in separation stages as the last back recovered fibers under unfavorable conditions contaminate or permanently damage. The prior art has also used a thermally used according to the invention Share of raw material still used for paper production. This Inferior proportion can according to the invention by other higher quality Fibers of the supplied for paper production raw material are replaced.

The thermal utilization of the discharged as waste shares improved In addition, the energy efficiency of the entire system.

The possibly additional costs due to any necessary larger supply of raw materials can by considerable Lower costs in the investment and operation of the treatment plants be covered. The less of that compared to the prior art recycled raw material produced paper has a higher quality, in particular improved optical properties and greater strength. Alternatively, you can even when compared to the prior art constant optical and mechanical properties, the basis weight ("basis weight") are reduced, resulting in appropriate ecological and economic Benefits.

According to the inventive method is from the raw material for paper production, in particular from a waste paper mixture, in at least a first processing stage of a sorting plant, deinking plant, Washer or a Cleaneranlage a fibrous waste content Separated, wherein the fibers of the waste content in at least one of first treatment stages downstream further treatment stage be obtained from the waste content, that the further treatment stage charged with the waste content from the first treatment stage becomes. This preferably, but not necessarily, includes the same Plant like the first treatment stage.

According to one other design goes through the invention however, the fraction of waste from the first treatment stage is none further preparation stage, at least no such, which the same Plant type such as the first processing stage, ie the raw material paper production is maximized by a single-stage sorting system, Deinkinganlage and / or Cleaneranlage out. In particular, it is possible to Waste content from the first treatment stage not at all but immediately all or part of it to use energy to produce energy then in the paper mill, in particular during processing, in the paper machine and / or in paper finishing is being used.

Due to the fact that, according to the invention, only a smaller number of processes are involved in total As has hitherto been customary in the prior art, the proportion of fibers in the waste portion remaining after the treatment stages is greater. This waste fraction from the various one-stage treatment plants is used to generate thermal and / or electrical energy, which, as shown, is fed to and used in one or more of the treatment plants and / or the paper machine and / or a subsequent paper finishing.

Without restriction to a single similar treatment stage, that is, without the restriction that in a rejektseitigen series connection maximum a single sorting plant, Deinkinganlage and Cleaneranlage provided is, is according to one alternative version the inventive method characterized in that the waste fraction behind the last Preparation stage has a fiber content of more than 8%. The last preparation stage with regard to the direction of movement of waste refers to the possible series connection several processing stages, such as a first, second and third, optionally pretreated (e.g., sorted) Raw material for paper production first the first processing stage is supplied, the waste content from this first treatment stage of the second treatment stage is fed the waste content from the second treatment stage of the third treatment stage supplied will, and finally the waste content of the third treatment stage, which in the example mentioned is the waste content "behind the last processing stage", for the production is used by thermal and / or electrical energy. The Numbering of the treatment stages in the context of the present Accordingly, the description of the invention does not refer to the way of the Acceptable material, on which usually also several treatment plants be connected in series, for example, as later with Referring to the figure will be described, a sorting system, a cleaner and a deinking plant.

These Processing plants on the way of the accept, which not are loaded with a waste content, all present in the present case referred to as the first preparation stage.

Especially is used for thermal or electric power generation Waste component from the last stage of preparation used to Fuels, in particular hydrogen, hydrocarbons such as methane, Alcohol or methanol to produce, which optionally treated and subsequently at one or more points of the paper preparation, production and or refining process are oxidized or burned. In the biogas plant can in addition to the fibers not used for papermaking also other biological scraps added be such as foliage, bark or the like, the Example in the raw material production of the raw material for paper production attack.

The Gases obtained in the biogas plant are used in particular in fuel cells used to generate electrical energy and / or process heat.

The Heat generated from the waste portion of the last stages can directly or indirectly in the raw material processing, papermaking or Paper finishing process can be used, especially in combination with catalytic combustion. In catalytic combustion are all heat transfer mechanisms possible, such as radiation, convection, direct heat transfer or indirect heat transfer via intermediary Heat transfer medium (for Example water or oil). Also a combination of different heat transfer mechanisms is conceivable.

The in the preparation stages, in particular exclusively first Processing stages obtained fiber mixture for a paper machine is advantageous directly, that is without further treatment and in particular without intermediate storage, one Supplied to paper machine, usually directly to the headbox of the same.

The 1 shows a schematic representation of the inventive method and the 2 a variant of the method.

A raw material for paper production 1 , which consists in particular of a waste paper mixture or comprises such, is first a sorting plant 10 fed. In this sorting plant 10 For example, in one of a take-up drum for waste paper downstream sorting drum accepts a share 2 from the raw material 1 won and the remainder of the raw material 1 as waste content 5 dissipated. The dissolution can also be effected by suspending in a so-called pulper, to which water and optionally chemicals are added to the raw material 1 soften and suspend the fibers in water. The subsequent sorting system can then consist of pressure sorters in which the already dissolved and placed in suspension waste paper material is sorted by sieving.

The accepted share 2 becomes a cleaner system 11 supplied, for example, a heavy-duty cleaner or light-dirt cleaner. In this cleaner system 11 is the still polluted Faserstoffsus pension accelerated in a vortex. Fabrics that are lighter than the paper suspension, the eddy current transported to the inside and heavier materials to the outside. The waste content 5 from the cleaner system is, as shown schematically in the 1 is shown, with the waste content from the sorting system 10 mixed and transported on.

A series of connected screens and slots can remove substances such as adhesive and plastic residues. The accepts 3 from the cleaner system 11 is now fed to a deinking plant to remove printing inks and fine contaminants. Even if such systems have been developed for the removal of printing inks ("ink"), today they are used to remove all fine impurities, in particular stickies, for example, the deinking plant can be used as a flotation plant 12 be carried out in which in a single or in a plurality of flotation cells the accept 3 from the cleaner system 11 or generally the paper pulp water, such as caustic soda and soap, is added, and with air bubbles, a foam is generated, with which drive the paint components to the surface, where they are skimmed off. Of course, other deinking processes can be used, for example washing deinking, which mechanically removes the fibers from the impurities entering the filtrate.

The accepts 4 from the flotation plant 12 can now, optionally after further processing or directly, the paper machine 14 be fed, for example, the headbox of the same, so that from the accepts 4 the paper 6 is produced. Subsequently, a paper finishing can follow (not shown).

The waste content 5 from the flotation plant 12 will with the waste shares 5 from the sorting plant 10 and the cleaner system 11 merged and then in a biogas plant 13 used to generate at least one fuel. This fuel is then burned, for example, in particular by catalytic combustion, or oxidized to generate electrical energy in a fuel cell. The thermal energy obtained from the combustion can either be used to generate electrical energy, for example in a gas-fired power station, or directly to the paper machine 14 or one of the processing stages for the raw material 1 , here the sorting plant 10 , the cleaner system 11 or the flotation plant 12 be supplied. Also, the electrical energy which is generated by a fuel cell directly from the fuel produced in the biogas plant or indirectly via combustion of the fuel produced in the biogas plant, the paper machine 14 or for the operation of the production hall with the paper machine 14 or one or more of the treatment stages as shown, and used there. Alternatively, the waste content 5 conventionally burned for energy.

According to the description of the present invention, the processing stages shown are with the sorting plant 10 , the cleaner system 11 and the flotation plant 12 referred to as the first processing stage, since they are the first processing plant of a particular type, which is the raw material 1 or the acceptance share 2 or the accept 3 is supplied.

In each of these first treatment stages, one waste component is added 5 produced according to the in the 1 illustrated embodiment, no second downstream treatment stage is supplied, but directly for the production of thermal and / or electrical energy or for the production of fuel in the biogas plant 13 is used. In contrast, according to the prior art, it was customary to use these waste components 5 to undergo a further treatment in order to extract in this waste fraction still contained fibers and fed back as accepts the paper machine. According to 2 the process objective can also be achieved if only one of the treatment plants, in this case the flotation plant particularly suitable for this purpose 12 , operated with reduced pulp production, so an increased waste content 5 is formed. The sorting system 10 is in this case three-stage (project-related) and the cleaner system 11 two stages. Thus, their waste shares 5 ' separated with more effort than fiber in the example according to 1

According to one embodiment of the invention, not all of the waste content is 5 from the various processing plants of the biogas plant 13 fed but in the biogas plant 13 non-recyclable substances in the waste content 5 can be suitably separated out beforehand.

Claims (12)

Method for producing a fiber mixture ( 4 ) for a paper machine ( 14 ) from a raw material ( 1 ) for the production of paper, in particular from a waste paper batch, comprising the following steps: 1 ), in particular the waste paper mixture, is in at least one sorting plant ( 10 ), Cleaneranlage ( 11 ), Flotation plant ( 12 ) or a washing plant or a combination of these plants, in which the accept of an upstream plant is led to a downstream plant, a fibrous waste fraction ( 5 ), the fibers of the waste portion ( 5 ) of the first treatment stage of the treatment plant in one of first treatment stage after connected second treatment stage or a plurality of treatment stages downstream of the first treatment stage by means of in each case at least one further sorting installation, cleaner installation, flotation installation or washing installation from the waste component ( 5 ) are obtainable, characterized in that the number of treatment stages of the treatment plant or treatment plants is selected to be so high that thereby a waste content ( 5 ) is produced at the end of all treatment stages, which has a higher proportion of fiber compared to a treatment with a higher number of treatment stages of the treatment plants and in that this proportion of waste ( 5 ) is used to generate thermal or electrical energy which is wholly or partly for the production of the fiber mixture or the paper machine ( 14 ) or a subsequent paper refining is supplied. Method according to claim 1, characterized in that a flotation plant ( 12 ) is used. A method according to claim 1 or 2 for the production of graphic paper or packaging paper, characterized in that the proportion of waste used for the production of thermal or electrical energy ( 5 ) has a pulp content of more than 8%. Method according to claim 3, characterized in that the proportion of waste used for the generation of thermal or electrical energy ( 5 ) has a pulp content of more than 20%. Method according to Claim 1 or 2, characterized in that the proportion of waste used for generating thermal or electrical energy ( 5 ) has a pulp content of more than 30%. A method according to claim 5, characterized in that the proportion of waste used for the generation of thermal or electrical energy ( 5 ) has a pulp content of more than 50%. Method according to one of the preceding claims, characterized in that a maximum of a single processing stage at sorting plant ( 10 ), Cleaneranlage ( 11 ), Flotation plant ( 12 ) or car wash is used. Method according to one of the preceding claims, characterized in that from the proportion of waste used for the generation of thermal and / or electrical energy ( 5 ) in a biogas plant ( 13 ) Fuels, in particular hydrogen, hydrocarbons, methane, alcohols or methanol, are recovered, which are oxidized or burned to generate the thermal and / or electrical energy. Method according to claim 8, characterized in that the waste fraction ( 5 ) additional biological waste is added. Method according to one of claims 8 or 9, characterized in that the heat produced during the combustion at least partially directly to one or more treatment stages, the paper machine ( 14 ) and / or the paper finishing is supplied. Method according to one of claims 8 or 9, characterized that the fuels in a fuel cell generate electrical energy and / or used by process heat. Method according to one of claims 8 to 10, characterized in that the heat produced during the combustion at least partially converted into electrical energy and that this one or more treatment stages, the paper machine ( 14 ) and / or the paper finishing is supplied.