JP2020082032A - Pulp sludge dehydration apparatus - Google Patents

Abstract

To dehydrate and reuse pulp sludge without adding any additives or other substances.SOLUTION: A pulp sludge dehydration apparatus has a device that receives input of a type of pulp sludge in pulp sludge and selects any collection box having a filter part corresponding to the type of pulp sludge from the information; and a plurality of the collection boxes each having a filter part corresponding to the type of pulp sludge.SELECTED DRAWING: None

Description

The present invention relates to a technique for dehydrating and recovering solids contained in pulp sludge, which is industrial waste.

In the papermaking process, the pulp residue (hereinafter referred to as pulp sludge) contained in the wastewater derived from the pulp selection process such as the pulp beating process or the papermaking process after the stock preparation is a paper produced by the fiber length or the like. The paper was not made into paper because it was too short to meet the standard. These pulp sludges are usually appropriately dehydrated.

As the dehydration treatment, it is common to introduce wastewater into a sedimentation tank to precipitate the pulp sludge, and then discharge excess water as a supernatant to recover the pulp sludge. Since this method requires a long time for precipitation and dehydration, the pulp sludge can be used for other purposes due to the inclusion of impurities during the precipitation or after the precipitation, and the deterioration of the properties due to rot etc. before the collection after the precipitation. It becomes difficult to divert to. For this reason, the pulp sludge after dehydration is generally recovered as waste paper or sludge as industrial waste, and incinerated or landfilled.

Further, in recent years, as a method for suppressing the above property deterioration and dehydrating pulp sludge more rapidly, a method of mixing with a phenolic substance and a polyalkylene oxide aggregating agent to agglomerate (for example, refer to Patent Document 1), a specific method A cationic water-soluble polymer containing 5 to 100 mol% of one selected from cationic structural units and 0 to 95 mol% of each of nonionic structural units, and one selected from specific cationic structural units. A method of using a mixture of an anionic water-soluble polymer and a mixture of an amphoteric water-soluble polymer each containing 5 to 70 mol% and an anionic structural unit of 5 to 50 mol% (for example, see Patent Document 2). Is proposed.

Japanese Patent Publication No. 2002-500104 JP, 2003-181500, A

The methods of the prior art documents are all aimed at adding an additive to pulp sludge to obtain a dehydrated cake having a low water content, and do not mention reuse of the dehydrated cake. Further, by using an additive such as a coagulant for dehydration, the component becomes different from the original papermaking raw material. Further, it is extremely difficult to separate the flocculant from the pulp sludge containing the flocculant. Further, it is difficult to disintegrate the dehydrated cake that has been aggregated by adding the coagulant, and even if it is possible to disintegrate, it is difficult to stably disperse the pulp as a papermaking raw material, which is a great barrier to reuse. Therefore, an object of the present invention is to dehydrate and reuse pulp sludge without adding an additive such as a flocculant.

The present invention to achieve the above object, the type of pulp sludge in the pulp sludge is input, a device for selecting a recovery box having a filter unit that matches the type of pulp sludge from the information, and matched the type of pulp sludge It is composed of a plurality of collection boxes having a filter section.

According to the present invention, it is possible to dehydrate pulp sludge and reuse solid contents without adding additives or the like.

Embodiments of the present invention will be described below. The pulp sludge described in the present invention is a suspension generated in the manufacturing process of a paper mill or the wastewater of a paper mill.

The present invention inputs a type of pulp sludge in pulp sludge, selects from the information a collection box having a filter unit that matches the type of pulp sludge, and a plurality of units having a filter unit that matches the type of pulp sludge. It consists of a collection box.

In recovering the solid content in the pulp sludge, the operator inputs the type of pulp sludge in the pulp sludge into a device that selects a recovery box having a filter unit that matches the type of pulp sludge. A keyboard for a computer or the like can be used as the input means to the device for selecting the collection box having the filter part that matches the type of pulp sludge.

An apparatus that inputs the type of pulp sludge and selects a recovery box having a filter unit that matches the type of pulp sludge from the information selects a recovery box that has a filter unit that matches the type of pulp sludge. As a method of flowing the pulp sludge into the selected recovery box, a method of selecting a water passage for each recovery box, for example, a method of changing the water passage by a valve device can be preferably used. The device that selects the recovery box having the filter unit that matches the type of pulp sludge sets the running water path to the recovery box that has the filter unit that matches the type of pulp sludge, and then starts passing water through the pulp sludge.

A plurality of collection boxes having a filter section that matches the type of pulp sludge has a filter section on the side surface of the collection box. The type of pulp sludge is selected according to the fiber length of the contained pulp. In the case of softwood pulp, since the fiber length is long, it is preferable that the size of each opening of the filter portion of the side plate is a square of about 1.5 mm in both length and width. This corresponds to a woven wire mesh defined by JIS G 3555, having a mesh of 10 to 16 and an opening of 1.35 to 1.65 mm. In the case of hardwood pulp, the fiber length is short, so it is preferable that the size of each opening in the filter portion of the side plate is a square having a length and width of about 0.6 mm. This corresponds to a woven wire mesh defined by JIS G 3555 and having a mesh of 24 to 30 and an opening of 0.55 to 0.65 mm. In the case of waste paper pulp, since the fiber length is usually shorter than that of hardwood pulp, it is preferable that the size of each opening of the filter portion of the side plate is a square of about 0.4 mm in length and width. This corresponds to a woven wire mesh defined by JIS G 3555, which has a mesh of 30 to 50 and an opening of 0.35 to 0.45 mm.

Further, in the case of pulp sludge containing at least two kinds of the above-mentioned softwood pulp, hardwood pulp and waste paper pulp, the type of pulp having the shortest pulp fiber length, for example, pulp sludge containing softwood pulp and hardwood pulp. If so, select a recovery box that has a filter part that matches hardwood pulp, or use a mesh (open) of the filter part that matches the type of pulp with the shortest pulp fiber length contained in the pulp sludge. Even if they are matched, the type of pulp having the shortest pulp fiber length may be selected as a dedicated recovery box separately from a single recovery box.

Inorganic components such as calcium carbonate, kaolin, silica, alumina and titanium dioxide contained in the pulp sludge as a filler are much smaller than the size of the pulp and pass through the filter of the recovery box according to the present invention. For this reason, when the filler is collected and used effectively, the wastewater that has passed through the collection box is collected again, and the collection is performed by the method described in JP2007-015874A and JP2005-329392A. Preferably.

Since the recovery box used in the present invention contains the solid content containing water, it is preferable to take measures to prevent corrosion or rust, or be formed of a material that is unlikely to cause corrosion or rust. As a method, it is preferable to manufacture each member of the recovery box from a plastic material or a stainless material, to apply rust preventive coating to each member, and to subject the material to a plating treatment having corrosion resistance.

The pulp concentration in pulp sludge is very low, and the specific gravity of pulp is almost the same as water, and dehydration does not proceed.Therefore, after the pulp sludge is put into the collection box, filter the inside of the collection box or centrifuge it. A mechanical dehydration treatment may be carried out by separation or the like.

Pulp fiber and filler are contained in the solid content obtained by dehydration recovery. When the pulp or other organic component in the recovered solid content is mainly used, it is used as a raw material for corrugated cardboard raw materials, containers, etc., paper clay, etc. Alternatively, it is preferable to thermally recycle the fuel for the boiler or the like. When the filler is to be recovered from the waste water after the solid content is recovered, it is preferable to collect it by a method such as adding an additive suitable for the filler separately and causing it to aggregate.

Claims (1)

By inputting the type of pulp sludge in the pulp sludge and selecting a collection box that has a filter section that matches the type of pulp sludge from that information, and a plurality of collection boxes that have a filter section that matches the type of pulp sludge Composed pulp sludge dewatering device.