JPH01306693A - Dehydration accelerator and dehydration accelerating method for pulp slurry - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a dehydration accelerator and a method for accelerating the dehydration of pulp slurry in various pulp manufacturing processes.

B. Conventional Technology In the pulp manufacturing process, numerous filters are installed for purposes such as cleaning, S reduction, and manufacturing of valve seats. In this case, if the dehydration properties of the pulp slurry are poor, the cleaning properties will be reduced, and for example, in bleaching process filters, in addition to increasing the cost of bleaching chemicals and heating steam, pitch in the process water etc. The deposit-forming material is carried over to subsequent processes, causing serious pitch problems. Other than this.

Poor dehydration of pulp slurry is often an important factor limiting pulp production capacity.1 For example, poor dehydration in a valve seat manufacturing machine can cause sheet breakage due to crushed edges in the press part, which can only significantly reduce productivity. First, the rise in sheet moisture may lead to non-standard products, and if drying equipment is available, the amount of steam used will increase.

For the reasons mentioned above, there has been a strong desire for an effective method to improve the dewatering properties of pulp slurry.One example is the cationic polymer coagulants and flocculants used as dehydrating properties improvers in the paper manufacturing process. Polyethyleneimines, polyamide polyamines, polyamines, acrylamide polymers, etc. are not effective against pulp in the pulp manufacturing process.

Or it shows only a small effect. The reason for this is thought to be that the pulp fibers are unbeaten or only slightly beaten in the pulp manufacturing process, and are therefore in a coarse fiber state with almost no fibrillation or fineness. In other words, the main mechanisms of action of the above-mentioned polymer coagulants and flocculants used in the paper manufacturing process are (I) agglomeration of fine fibers on the fiber surface, which increases water permeability; and (2) neutralization of charges on the fiber surface. This is said to be due to the fact that 2-ipryl leans back and the hydraulic surface area decreases, but the reason why the pulp fibers in the pulp manufacturing process do not have an effective effect is that they do not have fine fibers or fibrils to act on. Another reason is that these polymer coagulants and flocculants cannot be expected to have a blocking effect on coarse fibers due to the rigidity of the fibers, the large distance between fibers, and other reasons.

C1 Objective of the Invention The objective of the present invention is to solve the aforementioned unresolved problems. The inventors have promoted the dewaterability of pulp slurry using an economical method, thereby reducing the utility requirements of pulp production.

In order to prevent the formation of pitch, etc., and ultimately improve productivity and pulp quality, we are conducting intensive research based on theory and experiment2.
As a result of repeated efforts, the present invention was completed.

D1 Structure of the Invention The dehydration accelerator for pulp slurry of the present invention is a compound represented by the following general formula (I): R-0(-C,H,O)nH...-curve=-CI)?
The method for promoting dehydration, which is constituted as an active ingredient, is also constituted by adding the compound of -formation (I) during the upstream process of the filter for pulp slurry.

The amount of the pulp slurry dehydration accelerator of the present invention varies depending on the type of pulp, slurry characteristics (temperature and pH, etc.), filter characteristics, etc., but usually 50 to 8
About 0.00 ppm is preferable.

The preferred addition location is a location before the filter where it can be thoroughly mixed into the pulp slurry.

It should be noted that, as long as it does not impede the achievement of the object of the present invention, any other optional component 1, such as a solvent, may be used in combination.Next, the present invention will be explained in more detail with reference to Examples.

E. Example Using a pulp slurry (pulp concentration 111.7%) collected from a chlorine bleach stage filter vat of a certain raft factory, the dehydration effect of the dehydration accelerator of the present invention and a comparative reference product was investigated. The results are shown in Table 1.

Experiments Nos. 1 to 4 in the table are products corresponding to the present invention, and Nos. 5 to 8 are comparative examples. The dehydration test equipment test conditions were as follows, and the pulp yield in the valve seat after dehydration was calculated using the following formula.

O dehydration test equipment Kanmoto Seisakusho vacuum dehydration equipment (MODEL VR-22)
It was used with a Y connection (Buchnerrow) with plastic wire stretched over it.

O Dehydration test conditions Depressurization degree: 10 cmHg (P Over-dehydration time: 30 seconds Slurry temperature: 50℃ At the time, we were producing 200 tons/day, but due to the cracking of the edges in the press part due to poor dehydration, sheet breakage occurred frequently, resulting in a decrease in productivity.

The experiment number of Example 1 is placed in the level box in front of the circular mesh bat.
, Compounds corresponding to 3.4? 500 per ton of bone dry bulb
When ppm was added, immediately after the addition, a reduction in the level of circular mesh butt due to the effect of improving dehydration was observed, and there was no sheet breakage due to edge breakage in the press part, which had previously occurred frequently. It was confirmed that stable operation was possible even when the production amount was further increased to 230 tons/day, and the moisture content of the final valve seat product did not increase.

F0 Effects of the invention According to the valve slurry dehydration accelerator and dehydration accelerating method of the present invention, it is possible to improve the dehydration properties of pulp slurry, reduce the required amount of utilities, and prevent pitch troubles, etc., using safe chemicals and a simple method that are cost-effective. Not only is this achieved in terms of efficiency, but it also has a significant effect on increasing valve productivity and improving the quality of the final pulp product.

Claims (1)

[Claims] 1. A dehydration accelerator for pulp slurry, characterized by containing a compound represented by the following general formula (I) as an active ingredient. R-O■C_2H_4O)_nH......(I) [In the formula, R represents an alkyl group or alkenyl group having 8 to 22 carbon atoms, and n represents an integer of 1 to 4. 2. A method for promoting dewatering of a pulp slurry, which comprises adding the compound according to claim 1 during a process upstream of a filter for pulp slurry.