JP2535175B2 - Quantitative determination of pitch for preventing pitch damage in pulp and paper manufacturing process - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for easily predicting a pitch (resin) obstacle, a so-called pitch trouble, which occurs in a manufacturing process of pulp or paper, and a pitch for preventing the pitch trouble based on it. Regarding the quantitative method of.

2. Description of the Related Art Pitches in the manufacturing process of pulp or paper (the term "pitch" as used herein usually means a natural resin or a gummy pitch released from wood cells in the manufacturing process of paper or pulp, and other additives). (Means small spherical sticky agglomerates mainly consisting of organic substances derived from the treatment of waste paper and waste paper)
Such pitches are agglomerated and adhered to various places in the paper manufacturing machine equipment such as the cost, beater, and wire in the above manufacturing process, which lowers the work efficiency, or mixes in the product to cause stains or holes in the pulp sheet or paper. It causes various pitch troubles such as the cause.

Conventionally, various methods have been adopted as measures for preventing such pitch troubles, but the most effective and general method is, for example, an adsorbent such as fine talc or kaolin, or a sulphate sulfate or polyphosphorus. Acid salts, various surfactants, emulsifiers, etc. are used.

By adding these adsorbents, surfactants or emulsifiers to the process water in appropriate places in the pulp and paper manufacturing process, the pits precipitate in the liquid and aggregate into particles of a certain size. It has a remarkable effect in suppressing the adhesion to the mechanical equipment or the detachment of the mechanical equipment to adhere to the paper.

However, in this method, each inhibitor described above is added at the stage when a pitch trouble occurs during the operation of the manufacturing process, or the necessity of the addition of the inhibitor is grasped in advance based on the experience in the past operation. Since it is used, because it does not predict the pitch trouble in the process water in the manufacturing process of pulp and paper, and does not use the inhibitor,
There is a problem in that it is not possible to use the proper amount of inhibitor.

That is, these conventional methods cannot prevent pitch troubles.

Generally, the occurrence of pitch trouble is said to be greatly affected by the difference in the type of manufacturing raw material, but the occurrence of the pitch trouble also has a delicate influence due to the difference in manufacturing equipment and manufacturing conditions. Furthermore, in the multi-step and long-term pulp and paper manufacturing processes, the occurrence of this problem is extremely diverse, such as the location and amount of pitch deposited on equipment and products are not constant. ,
Even if the inhibitor is used according to the occurrence of trouble, its addition is also estimated, so that it is difficult to perform appropriate inhibition.

In addition, as a preventive measure against pitch trouble, a method of washing the process water with fresh water after the conventional cooking or bleaching step has also been performed, in which case the number of washings and / or the amount of water is increased, or the step is contaminated. Although the above troubles can be effectively prevented by increasing the amount of water used for blowing, on the other hand, there are problems such as the saving of fresh water, the cost of cleaning equipment, and the complexity of work, which is not practical.

For the above reasons, various methods for predicting the occurrence of the pitch trouble have been proposed from the viewpoint that it is advantageous to predict the occurrence of the pitch trouble and appropriately prevent the occurrence of the trouble based on the above.

Among these prediction methods, the amount of extract containing pits in the process water by Soxhlet extraction, the propeller made of copper or stainless steel, the amount of pits attached to the shaft, and the amount of pits attached to the felt for papermaking are measured. Quantity measurement,
Furthermore, the number of colloidal pitches in process water has been measured, and among them, as an easy-adhesive quantitative determination method for pitches that causes pitch troubles, the amount of adhesion on stainless steel or papermaking felt can be measured. It is the most common because it is simple and directly meets the purpose of measurement. However, these quantitative methods have a difficulty in accuracy because the absolute amount of adhered pitch is extremely small on the scale of a test apparatus. For that reason, various improvements have been tried, but at present, it cannot be said that they have been sufficiently successful.

Problem to be Solved by the Invention The present invention has been made in view of the above situation,
An object of the present invention is to provide a method for predicting the occurrence of pitch troubles and effectively preventing the occurrence of pitch troubles based on the method, for quantifying the pitches in the process water in the pulp or paper manufacturing process.

That is, the present invention, by adsorbing and quantifying the easily adhering pitch in the process water, predicts the pitch trouble by continuously and accurately measuring the amount of adhered pitch, thereby appropriately preventing the pitch trouble. Is what makes it possible.

 The present invention will be described in detail below.

Composition of the Invention The feature of the present invention is to adsorb and quantify pitch in the process water in the production of pulp or paper by adsorbing it on the carbon fiber material or activated carbon fiber material.

Means for Solving the Problems The present invention, in the production of pulp or paper, a pulping process in which pitch troubles are likely to occur, a bleaching process, a waste paper treatment process, a papermaking process, etc. The amount of carbon fiber is measured by adsorbing it on a material or activated carbon fiber material, and the carbon fiber material used here is carbon fiber itself and a woven fabric, felt, carbon net, carbon plate obtained by processing it. , Carbon rods, etc.
In addition, as the activated carbon fiber material, activated carbon materials can be used. These materials preferably have a large surface area from the viewpoint of adsorption ability, and they are used alone or reinforced with a support.

Since these materials selectively adsorb the easily adhering pitches in the above process water, in order to measure the amount of adhering pitches using them, test pieces of carbon fiber material or activated carbon fiber material are used for pulp and paper. Immersed in water for the manufacturing process of
Selectively adhere the water-adhesive pitch for the process to a test piece, measure the weight change of the test piece, and measure the amount of pitch recovered by the solvent from the test piece after measurement or the difference between the amount of pitch before and after measurement. It is advisable to quantify the above-mentioned easily-adhesive pitch, and the quantitative value is used for prediction of pitch trouble.

In actually quantifying the easily attachable pitch in the process water by the test piece, the pulping step in which a lot of pitch troubles occur in the manufacturing process of pulp or paper, the step before the bleaching step and the papermaking step, For example, it is preferable that the inlet of the completed tower after the washing step and the cheest of the adjusting step be the measurement points, and the measurement points may be two or more points if necessary.

Next, the amount of attached pitch in the process water is measured, and when the risk of pitch trouble is predicted, preventive measures against the occurrence of pitch trouble are taken.

The steps for carrying out the above preventive measures in the pulp and paper manufacturing process are steps in which pitch trouble is likely to occur or steps before it, such as an inlet of the bleaching step, an outlet of the completed tower after the washing step, and a control step Etc.

The preventive treatment can be carried out by addition of the above-mentioned pitch trouble suppressor, for example, talc, kaolin, sulphate, polyphosphate, various surfactants, emulsifiers, etc. By predicting the occurrence of pitch troubles in this manner, it becomes possible to appropriately perform the addition location and addition amount of these inhibitors.

Further, as the above-mentioned preventive measures, a conventionally used method of washing process water with fresh water, a method of blowing a part of the process water, or the like can also be used. It should be noted that these preventive measures may be appropriately selected depending on the degree of occurrence of a pitch disorder, that is, the size of the easily adhesive pitch measurement amount.

Furthermore, by measuring the amount of easily adhering pitches, it is possible to determine whether or not there is a possibility that a pitching trouble will occur, or its low level, so it becomes possible to appropriately carry out preventive measures, and perform extra preventive measures as in the past. This is a good idea in terms of resource saving and economy.

In addition, since the pit particles are strongly negatively charged in the process water, applying a direct current voltage to the conductive carbon fiber material or activated carbon fiber material to make it positive charge increases the pit attachment rate and attachment amount. To do. The above-mentioned application in the present invention is such that these materials do not cause electrolysis, particularly 10 to 20 V.
Is desirable.

Hereinafter, the present invention and its effects will be specifically described with reference to examples.

Example 1 Circulating white water (100 liters) in a paper pulp manufacturing process was collected and circulated in a laboratory at a flow rate of 500 ml / min, and a stainless steel plate (thickness 2 mm) or a mesh of 20 mesh, activated carbon was in the middle of the circulation. Fiber felt (thickness 4 mm), carbon fiber fabric (thickness 1
mm), activated carbon fiber fabric (thickness 0.2 mm), nylon felt (thickness 8 mm)
The weight increase due to the attachment of the pitch after a certain period of time was measured. At the same time, the amount of extract in white water was measured by extraction with ethyl acetate. The weight of each test piece is 10 g for stainless steel plate, 5 g for stainless steel net, 0.5 g for activated carbon fiber felt, 0.5 g for activated carbon fiber fabric, 1.5 g for carbon fiber fabric, 5 g for nylon felt, and they are almost the same. Is the size of.

Table 1 shows the amount of pitch attached to the test piece after 3 hours, 6 hours, and 24 hours when the unbleached kraft / washing process water was used.

As can be seen from Table 1, the amount of adhesion to stainless steel is extremely small, and an accurate amount of adhesion cannot be obtained without careful measurement. In addition, there is almost no difference due to time, and it is difficult to predict the amount of easily attached pitch using stainless steel. On the other hand, the amount of adhesion to the carbon fiber material, especially to the activated carbon fiber material is extremely large, and it is most suitable for tracking the fluctuation of the easy adhesion pitch.

Example 2 Softwood unbleached kraft pulp washing process water (NUKP white water),
Using the circulating water (GP white water) of the groundwood pulp manufacturing process and the final chlorine dioxide stage washing water (LBKP white water) of bleached hardwood kraft pulp, the amount of adhesion to each test piece after 24 hours was measured in the same manner as in Example 1. The results are shown in Table 2.

As seen in Table 2, when the carbon fiber material was used, the amount of adhered pitch was extremely large, and the total amount of pitch (extract amount) was good.
Is proportional to.

Example 3 Pitch particles are strongly negatively charged in process water. Therefore, if a positive charge is applied to the test piece made of a conductive carbon fiber material, it is considered that the attachment speed and the attachment amount of the pitch are increased. Therefore, the same adhesion test as in Example 1 was conducted while applying a positive charge to the carbon fiber test piece. The voltage was applied within a range that does not cause electrolysis. Carbon fiber fabric (1.5 g) was used as a test piece, and GP white water (total pitch amount: 162 mg / l) was used as a white water sample. The adhered amount after each time was measured. The results are shown in Table 3.

As can be seen from Table 3, when a voltage is applied to the test piece, a remarkable increase in deposition rate is observed, and the deposition amount is comparable to that measured at 10 V within 30 minutes for 0 V charging for 3 hours or longer.
That is, the measurement time can be significantly shortened. As a result, pitch troubles can be predicted quickly and countermeasures can be taken promptly.

By the method of the present invention, if an increase in the amount of easily adhering pitches in the process water is observed, it is possible to add the above-mentioned anti-pitch trouble agent or inhibitor, or to take other appropriate measures to prevent the problem. Can be prevented.

As is clear from the above description, the method for preventing pitch troubles in the manufacturing process of the pulp or paper according to the present invention,
It is a method of predicting the occurrence of such obstacles by an extremely simple and reliable measurement value of the easily adhering pitch amount of process water, and preventing pitch troubles accurately without excess, shortage, resource saving, cost reduction It can be said that it is an extremely effective method from above.

Claims (2)

(57) [Claims] 1. A method for preventing pitch trouble in a pulp manufacturing process and a paper manufacturing process, characterized by adsorbing a pitch in water for a process in pulp manufacturing or paper manufacturing to a carbon fiber material or an activated carbon fiber material to quantify the pitch. Method of pitch determination. 2. The quantitative method according to claim 1, wherein a direct current voltage below electrolysis is applied to the carbon fiber material or the activated carbon fiber material to positively charge it to adsorb the pitch.