RU2814436C1 - Cellulose and cellulose-based materials fluffing device - Google Patents

Abstract

FIELD: cellulose industry.

SUBSTANCE: invention relates to a device for processing cellulose in the form of sheets, namely for producing fluff pulp, cellulose-based materials. Device for fluffing cellulose consists of a rotary grinder of sheets or layers of cellulose of impact or impact-abrasive action, mechanical classifier of fluffing products, pneumatic transport of fluffing products, a device for separation of fluffing products and waste air, a collector of fluffed cellulose, an air blower and a device for cleaning waste air emitted into the atmosphere. At that, at least one settling and/or filtering chamber is used as one of the stages of the device for separation of fluffing products and waste air. Settling chamber is connected to the grinder through the material line and has a detachable or hinged cover, or a hatch for removal or installation of a removable collector of fluffed cellulose, and the device additionally contains a feeder for supply of cellulose sheets with adjustment of speed of linear supply of sheets. Air duct branches after blowing machine, thus forming an air duct for recirculation of part of exhaust air and a device for controlling the amount of exhaust air emitted into the atmosphere or the ratio of exhaust air emitted into the atmosphere and directed for recirculation.

EFFECT: invention increases efficiency, improves quality of fluffed cellulose and reduces power consumption.

10 cl, 1 dwg

Description

The invention relates to devices for producing fluff pulp, cellulose-based materials, c. incl. production of thermal insulation, for example, ecowool, for the preparation of cellulose in the production of chemical derivatives of cellulose, for example, cellulose ethers, in the production of cellulose materials used as reinforcing fillers of polymer composite materials, as well as in the pneumatic transportation of fluff cellulose.

Cellulose-based materials, incl. thermal insulation, made from cellulose or cellulose-containing raw materials, incl. from recycled materials. In this case, the feedstock can be in a dense form - in the form of compressed bales, rolled paper or flat sheets - the so-called (so-called) cellulose folder.

One of the characteristic properties of cellulose as a material is its fibrous form, due to the natural structure of the feedstock. Cellulose in plant raw materials is in the form of plant fibers - elongated particles with a round or multifaceted cross-section and pointed ends. In this case, the length of the fiber is many times greater than its thickness. A feature of cellulose fibers is the ease and spontaneity of aggregation. In a free state, the fibers begin to interact with each other and form hydrogen bonds, weak in nature, but in huge quantities. Therefore, cellulose-based materials have the so-called. coherent and form aggregates - flakes or lumps. These aggregates can be destroyed and disaggregated under certain mechanical, aerodynamic or hydrodynamic influences, separating individual fibers. In the absence of such influence, as a rule, the fibers of cellulose and cellulose-based materials tend to spontaneously form a network structure. This structure underlies the flakes and lumps of cellulose raw materials.

The flocculent and lump-like structure of cellulose and cellulose materials is preferable or acceptable in the form of materials for end use - in thermal insulation layers of building structures of building manufacture, thermal insulation products, for example, slabs. When using cellulose as the reinforcing filler of a polymer composite material, the fluff form may also be preferred. Also, this form may be appropriate when carrying out chemical modification - processing cellulose with chemical reagents. The developed surface area contributes to the good reactivity of the raw material. This is useful when preparing cellulose ethers, for example, carboxymethylcellulose, polyanionic cellulose, cellulose nitrates, etc. Moreover, in the process of technological processing, it is often necessary to have cellulose in the form of dispersed particles, i.e. in the form when cellulose aggregates are destroyed and cellulose fibers are more or less separated from each other. This is due to maintaining the required concentration gradient of chemical reagents, water, solvents during chemical processing of cellulose, during washing, impregnation with binders, filtration, dehydration, drying, hydraulic or pneumatic transportation, etc. That is, during processes associated with the formation and maintenance of gradients - concentrations, temperature, pressure, for mass transfer processes, heat transfer and hydrodynamic processes.

In this regard, for processing, cellulose and cellulosic materials are subjected to dispersion into fibers using methods of mechanical loosening or mechanical defibration or aerodynamic fluffing, as well as hydrodynamic breaking. Several analogues of the proposed device are known from the prior art.

For example, a checker is known (Zabelin, L.V. Cotton cellulose: a textbook. / L.V. Zabelin, A.P. Zakoshchikov, V.K. Postnikov - M.: TsNIINTI and TEI, 1976. -280 p. ), used for loosening baled cotton linters, the raw material for pulp production. The checker contains a housing with a peg rotor installed inside and a sieve deck, and also has a suction pneumatic transport with an air blower, a cyclone separator, and a collection of loosened cellulose for transporting loosening products. The disadvantage of the checker is the large volume of exhaust air emitted into the atmosphere, and the large required productivity for cleaning this exhaust air, the lack of productivity adjustment for the loosened product, manual supply of raw materials, large peak loads on the rotor drive when loosening layers of cotton linters, low quality of loosened cellulose.

A bale ripper is known for loosening bales of cellulose (Osin, A.I. Equipment for the production of energy-saturated materials. Textbook / A.I. Osin, A.S. Pivovarov, N.N. Volkova; Alt. State Technical University, BTI. - Biysk: Publishing House of Alt. State Technical University, 2010. - 94 p.), which consists of a body with a ripening chamber, inside of which there are three ripening drums with a drive, a belt conveyor for supplying raw materials for loosening, a suction pneumatic transport with a blower for transporting loosened cellulose, a cyclone separator, and a collector of loosened cellulose. The disadvantage of this bale ripper is its unsuitability for crushing flat sheets of cellulose or cellulose raw materials, high air consumption, and high required productivity for cleaning this exhaust air. It is also possible for large pieces of raw material to slip through.

A known machine for de-fibering (Chaschilov, D.V. Experience in studying the process of de-fibering cellulose materials and analysis of equipment operation: from a laboratory bench to an industrial installation / D.V. Chaschilov // From chemistry to technology step by step. - 2021. - T 2. - No. 1. - P. 29-39. - DOI 10.52957/27821900_2021 01_29. - EDN TIQZYB) containing a housing with a chamber for de-fibering, a pegging rotor with a drive, a sieve, a collection of de-fibered cellulose, and a suction chamber. The disadvantages of the de-fiber machine are the low productivity of the device, the inability to transport de-fiber products, manual supply of raw materials and manual unloading of de-fiber products.

A known defibre plant (Chaschilov, D.V. Experience in researching the process of defibration of cellulose materials and analysis of equipment operation: from a laboratory bench to an industrial installation / D.V. Chaschilov // From chemistry to technology step by step. - 2021. - Vol. 2. - No. 1. - pp. 29-39. - DOI 10.52957/27821900__2021_01_29. - EDN TIQZYB), containing a mill with a sieve deck, a material pipeline, a cyclone unloader, a filter, a fan. The disadvantages of a defletting installation are high air consumption, high required productivity for cleaning this exhaust air, high energy costs, high peak loads when grinding large pieces or layers of raw materials.

The closest device is a device for fluffing cellulose from compressed bales (Utility model patent RU 149010. Device for fluffing cellulose from pressed bales. Shamin K.I., Chernov A.A., Zotov V.G., Smirnov A.V. , Chizhevsky O.T. U1, 12/20/2014. Application No. 2014123134/12 dated 06/09/2014). This device contains a roller conveyor with a mechanism for feeding raw materials between counter-rotating toothed rollers, radially rotating combs made in the form of a package of removable cutters, and a discharge belt conveyor. The disadvantage of this device is its unsuitability for fluffing flat sheets of cellulose. This device is accepted as a prototype.

The technical objective of the present invention is to develop a device for fluffing cellulose, improving the quality of processed materials, increasing productivity, reducing losses of raw materials and reducing energy costs for the process.

The stated technical problem is solved by the fact that in a device for fluffing cellulose, including a rotary shredder of sheets or layers of cellulose with impact or shock-abrasive action, a mechanical classifier of fluff products, pneumatic transport of fluff products, a device for separating fluff products and exhaust air, a collection of fluff pulp, an air blower machine, a device for purifying exhaust air emitted into the atmosphere, at least one settling and/or filtering chamber is used as at least one of the stages of the device for separating fluff products and exhaust air, a centrifugal dust fan is used as an air blower, in As a grinder, a hammer mill with a sieve deck is used, or the grinder has a peg rotor as a working body, and also additionally contains a feeder for feeding cellulose sheets, for example, a roller type, with adjustable speed of linear feeding of sheets, an air duct for recirculating part of the exhaust air, a device for control the amount of exhaust air emitted into the atmosphere, and also use one of the types of soft industrial or transport containers with air-filtering walls as a settling chamber, for example, a woven bag or a soft folding container with walls, or additionally implement the placement of a woven bag or a soft folding container with filtering air walls inside a chamber with airtight walls; the device may also contain at least two settling and/or filtering chambers with switching shut-off valves, which can operate alternately according to the cycle “loading: separation of fluff products and exhaust air - unloading”.

Figure 1 shows a diagram of the device.

The proposed device contains a feeder 1, an impact or impact-abrasive type shredder 2, a material pipeline 3, a collection of fluff pulp 4, a settling chamber 5, a filter 6, a control valve 7, a damper 8, an air blower 9, a recirculation air duct 10. The material pipeline connects the grinder and settling chamber. The settling chamber has a detachable lid on which a removable collection container for fluff pulp is attached. After the blower machine, the air duct branches, forming a loop for recirculating exhaust air and a branch for releasing exhaust air into the atmosphere. The damper on the air duct is intended, for example, to facilitate switching on the device.

The regulating damper serves to control the flow of air released into the atmosphere.

The device works as follows. Sheet raw materials are fed by a roller feeder into the working chamber of the shredder. The required productivity is ensured by adjusting the linear feed speed of raw materials. In the shredder, the pulp sheets are crushed and fluff pulp is formed. The fluff pulp is separated from the unshredded pulp pieces by a mechanical classifier, such as a shredder screen deck. The fluffy cellulose is sucked into the material pipeline due to the vacuum created by the blower. Fresh air is also sucked in and recirculated air is supplied to the working chamber of the chopper. The fluff pulp, together with the air, moves to the settling chamber, where the fluff pulp is separated from the air thanks to a collector, the breathable walls of which retain fluff pulp particles and allow exhaust air to pass through. A certain amount of cellulose dust passes through the walls of the collection chamber along with the exhaust air. The exhaust air then passes through a blower. Part of the exhaust air is returned to the shredder through the air duct. The other part passes through a filter, where dust is removed, and is released into the atmosphere. To regulate the amount of exhaust air emitted into the atmosphere or the ratio of exhaust air emitted into the atmosphere and sent for recirculation, a control damper is used, which can be made on the basis of a standard dust-gas-air pipeline valve with an MEO drive.

The device is comparatively simple, does not emit waste air in large quantities, and reduces energy consumption for transporting air and overcoming the hydraulic resistance of the filter. The quality of fluff pulp is also improved due to the uniform supply of raw materials by the feeder with adjustable speed of linear feeding of sheets, the absence of local overloads of the chopper drive, and the slippage of pieces of insufficiently fluffed pulp. The absence of overloads reduces energy consumption for processing raw materials in the grinder, and also allows you to increase productivity due to uniform processing of raw materials.

The movement of exhaust air during recirculation is ensured by the pressure difference between the air collection chamber and the cellulose fluffing chamber created by the fan. Regulation of the ratio of the flow rates of the emitted and recirculated exhaust air is ensured using, for example, a rotary valve that provides throttling of the recirculated air. Due to incomplete tightness of the joints of pneumatic transport material pipelines, air is sucked in, which eliminates the possibility of complete recirculation of exhaust air. Also, the need to release part of the exhaust air is determined by the need to let fresh air into the fluffing chamber, which eliminates the accidental release of contaminated exhaust air into the production room. The return of recirculated exhaust air occurs in the area of the fluffing chamber.

Recirculation of exhaust air reduces the need for fresh air, reduces losses of raw materials with exhaust air, reduces air pollution in the production area and in the ambient air, and reduces losses of raw materials. It also reduces the amount of exhaust air sent for final cleaning before being released into the atmosphere, which allows the use of air purification devices, such as a filter, with a lower throughput. This also reduces the loss of cellulose raw materials carried away with recirculated exhaust air.

In another embodiment, soft production or transport containers with a breathable body can be used as a collection of fluff pulp. This container is fixed to the neck of the lid of the settling or filtering chamber, through which fluff pulp can be supplied along with transport air. Air passes through the walls, and the fluffy cellulose is retained inside the collection. A woven bag or a soft folding container made of fabric can be used as a collection. The use of a woven bag or soft collapsible container with filter walls can effectively capture cellulose fibers and separate them from the exhaust air, which reduces the loss of fluff pulp. The placement of this woven bag or collapsible soft container with air-filtering walls inside a chamber with airtight walls, the body of which has a detachable or hinged lid, or a hatch for removing or installing a collector, makes it technically possible to collect and remove exhaust air for its subsequent recirculation.

In another embodiment, it is proposed to use in the device at least two settling and/or filtering chambers installed parallel to each other with switching shut-off valves, which can operate alternately according to the cycle “loading: separation of fluff products and exhaust air - unloading”. This technical solution allows for continuity in the operation of the device, which allows increasing the productivity of fluff pulp. When the first chamber is filling, the second is unloading. Then, using switching shut-off valves, the chambers are switched. The first chamber is unloaded, and the second one is filled with fluff pulp. Then the work cycle is repeated again.

Alternatively, a hammer crusher or mill can be used as a shredder for fluffing the cellulose sheets. The hammer mill physically breaks down the cellulose sheets, fluffs it, and moves the fluff pulp along the surface of the classifier. The use of a hammer mill as a cellulose grinder provides increased operational reliability, since a standard design element is used, productivity is increased due to the forced movement of fluff pulp along the working surface of the classifier and reducing the possibility of clogging the classifier holes with pieces of fluff pulp.

In another embodiment, a peg rotor is used as a working body - a drum with pointed teeth-protrusions, having, for example, a cone shape. The use of a peg rotor ensures effective fluffing of cellulose due to the impact of pegs on pieces of raw material, which improves the quality of fluffed cellulose and reduces energy costs for fluffing.

In another embodiment, a sieve deck or a spat deck can be used as a classifier. This deck can be integrated into a chopper design or into a hammer mill. The sieve deck may, for example, have round holes made by punching. The sieve deck ensures that poorly fluffed or unfluffed pieces of raw material do not slip through, which improves the quality of the fluff pulp. The sleeper deck may have sleepers, for example, of a trapezoidal cross-section, forming holes that expand as the fluff pulp moves. This allows for easier passage of fluff pulp through the holes and reduces the possibility of clogging of the holes with pieces of fluff pulp. The spat deck has a higher throughput of fluff pulp, which increases the productivity of the device.

Alternatively, a roller feeder may be used as the feeder for feeding the pulp sheets. Rollers can be smooth or grooved. When the rollers rotate, the sheets are forced to be fed into the shredder for fluffing at the required linear feed speed. This eliminates sharp fluctuations in the power consumed by the drive due to the tearing off of large pieces of raw material and their possible pinching between the rotor and the stationary parts of the chopper. The use of a roller feeder ensures uniform processing of raw materials, the absence of peak overloads during operation of the chopper, less power consumption for the operation of the chopper, and improved quality of fluff pulp.

In another embodiment, a centrifugal dust fan can be used as a blower. This increases the reliability of the proposed device. The dust fan is well adapted to work in dusty exhaust air conditions. The dust fan has a larger cross-sectional area of the air channels and is less prone to possible dust clogging. The elimination of clogging ensures uniform delivery of fluff pulp and the absence of aggregation of fluff pulp during these clogging, which improves the quality of fluff pulp.

The proposed device for fluffing cellulose provides increased productivity, improved quality of fluffed cellulose by eliminating the “slippage” of insufficiently fluffed raw materials, reduced losses of raw materials during processing, reduced emissions of polluted air, and reduced energy costs for the process.

Claims (10)

1. A device for fluffing cellulose, consisting of a rotary shredder of sheets or layers of cellulose with impact or shock-abrasive action, a mechanical classifier of fluff products, pneumatic transport of fluff products, a device for separating fluff products and exhaust air, a collection of fluff pulp, an air blower, a cleaning device exhaust air emitted into the atmosphere, characterized in that at least one settling and/or filtering chamber is used as at least one of the stages of the device for separating fluff products and exhaust air, while the settling chamber is connected through a material duct with a shredder and has a detachable or hinged lid, or a hatch for removing or installing a removable collection of fluff pulp, and the device additionally contains a feeder for feeding cellulose sheets, with adjustable speed of linear feeding of sheets, while the air duct after the blower branches, forming an air duct for recirculation of a portion of the exhaust air; and a device for regulating the amount of exhaust air emitted into the atmosphere or the ratio of exhaust air emitted into the atmosphere and sent for recirculation. 2. The device according to claim 1, characterized in that a hammer mill with a sieve deck is used as a rotary grinder and mechanical classifier. 3. The device according to claim 1, characterized in that a peg rotor is used as the working body of the rotary chopper. 4. The device according to claim 3, characterized in that a sieve or spat deck installed inside the chopper is used as a mechanical classifier. 5. Device according to any one of paragraphs. 1-4, characterized in that a roller feeder is used as a feeder for feeding cellulose sheets. 6. Device according to any one of paragraphs. 1-5, characterized in that a centrifugal dust fan is used as a blower. 7. Device according to any one of paragraphs. 1-6, characterized in that soft production or transport containers with a breathable body are used as a collection of fluff pulp. 8. The device according to claim 7, characterized in that a woven bag is used as a collection of fluff pulp. 9. The device according to claim 7, characterized in that a soft folding container is used as a collection of fluff pulp. 10. Device according to any one of paragraphs. 1-9, characterized in that it contains at least two settling and/or filtering chambers installed in parallel with switching shut-off valves, which can operate alternately according to the cycle “loading: separation of fluff products and exhaust air - unloading”.

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