JPH0360707A - Filter for high viscosity material - Google Patents

Abstract

PURPOSE:To smoothly and uniformly release cake when a filter medium is backwashed by using the filter having a cylindrical filter element of a duplex- pipe structure. CONSTITUTION:A high viscosity material having 10-5000 poise viscosity at 300 deg.C is filtered by the filter, in which the cylindrical filter element is hung from its upper part and fixed to remove tiny solids, and the element is backwashed and regenerated. The filter is provided with at least the one element, and the element is a duplex-pipe structure consisting of an outer cylinder 1 and an inner cylinder 2. As a result, cake is smoothly and uniformly released when the filter medium is backwashed.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to the field of producing pitch for fibers in large quantities from petroleum-based or coal-based pitch, or of high viscosity materials such as polymers (in this case, the viscosity at 300"C It can be used in the field of refining (with a diameter of about 10 to 5,000 voids).

(Conventional technology) Conventional filtration methods use cylindrical filter media (filter elements)
This is a method in which the
It is disclosed in Japanese Patent No. 150378. In this method, the undiluted solution is supplied from the bottom via a valve, and the filtrate that has passed through the filter medium is collected at the top and recovered from the filtrate extraction valve.In the case of backwashing, after extracting the undiluted solution from the filtration container, Furthermore, the filtrate inside the filter medium is extracted, and pressurized gas is blown into it from the backwashing gas valve on the filtrate side for backwashing and regeneration. In this case, when filtrating low viscosity substances such as water, the liquid inside the filter medium is easily drained out as well as the liquid from the filter container, making it possible to backwash and there is no problem, but when high viscosity substances such as pitch polymers are being The remaining liquid is not drained smoothly, and the cake may peel off as the liquid is drained, and this progresses only unevenly. As a result, the backwashing gas does not act uniformly on the adhered cake, so that the backwashing effect cannot be sufficiently achieved.

(Problems to be Solved by the Invention) As mentioned above, in the conventional system, the filter element is suspended downward, so that backwashing of the filter element when filtering high viscosity substances such as pitch is difficult. When extracting the stock solution in the container, it is extremely difficult to extract the liquid in the filter medium under normal pressure due to its high viscosity. If you try to drain the liquid by applying pressure, the cake attached to the outer wall of the filter medium will peel off, but in that state, the cake peeling will not proceed uniformly.
A peeled part and a stuck part appear, and the pressurized gas during the next step of backwashing does not act evenly on the cake (this is because it leaks from the peeled part of the cake), resulting in uneven cake peeling. Regeneration becomes insufficient.

If backwashing and regeneration are insufficient, the filtration work will stall, and in some cases, the device will have to be disassembled and the filter media will have to be forcibly washed, resulting in a significant drop in operating efficiency.

On the other hand, in order to solve this problem, the present inventors have previously devised a method and device for filtering highly viscous substances (Japanese Patent Application No. 63-325974). With these methods and devices, the filtrate in the filter medium is reliably drained, and the backwash gas can uniformly and effectively act on the wall of the filter medium. For this reason, backwashing and regeneration can be performed quickly and reliably, making it possible to increase the operating rate in the filtration process, but it is somewhat difficult to recover the cake. That is, the cake accumulates on the filter medium attachment pipe (header), etc., and a separate step of washing and removing it with a solvent is added, which complicates the equipment such as the solvent tank and pressure pump.

Therefore, the purpose of the present invention is to make it possible to smoothly recover the cake while hanging the filter medium downward, and at the same time, to ensure that the remaining liquid inside the filter medium can be removed in preparation for backwashing, and to make it possible for the backwash gas to more effectively clean the filter medium. The object of the present invention is to provide a filtering device for high viscosity substances having a structure that acts on the wall.

(Means for solving the problem) An essential requirement for smooth backwashing and regeneration of filter media (filter elements) is to ensure that the liquid inside the filter media is completely drained when filtration is completed.

If backwashing is performed with filtrate remaining inside the filter medium, gas pressure will not directly act on the cake due to the resistance of the liquid in the residual liquid portion, resulting in insufficient peeling. On the other hand, if the liquid is removed reliably, the backwashing gas will act instantly on the entire filter media, and the gas pressure will be applied evenly to the adhering cake, achieving the purpose of backwashing and regeneration quickly and reliably. .

Based on this knowledge, the present invention has a structure in which the residual liquid inside the filter material can be easily extracted by special devising the filter material (filter element) itself.

That is, in the present invention, after filtering a high viscosity substance having a viscosity of 10 to 5000 voids at 300°C to remove minute solids,
A cylindrical filter element top-fixed hanging type filtration device capable of backwashing and regeneration is provided with at least one cylindrical filter element, and the cylindrical filter element has a two-piece structure consisting of an outer cylinder and an inner cylinder. The present invention relates to a filtration device for high viscosity substances characterized by having a double tube structure.

In the present invention, since the outer cylinder of the cylindrical filter element forms the filtration layer, the core outer cylinder is made of steel mesh, metal nonwoven fabric, or the like. The one-way cylinder is a thin-walled cylinder, and its surface is provided with a plurality of pores that function as a throttle valve to prevent the backwashing gas from directly exerting pressure on the outer cylinder. Due to the action of these pores, pressurization progresses slowly during draining for backwashing, and draining is performed without damaging the cake layer of the outer cylinder. Furthermore, since the lower part of the cylinder has an open surface communicating with the outer cylinder, it serves as a passage for gas after the liquid is drained.

When the liquid has been drained, the gas pressure acts evenly on the outer cylinder, so that the cake can be peeled off smoothly.

The present invention will be specifically explained below based on the drawings.

FIG. 1 shows an example of the main parts of the filtration device of the present invention.

The cylindrical filter element is composed of an outer cylinder 1 and an inner cylinder 2, a screw 3 for mounting the cylindrical filter element, and a tip M4 of the cylindrical filter element. The outer cylinder 1 forming the filtration layer is made of mesh, metal hand-woven cloth, or the like. Moreover, a plurality of pores are provided in the inner cylinder 2 at equal intervals, and an opening communicating with the outer cylinder is provided in the lower part.

(Function) The function of the present invention will be explained below with reference to the filtration device shown in FIG. 1 mentioned above.

The filtered stock solution enters the filtration container 5 through the nozzle 6, passes through the outer tube (filtration layer) 1 of the cylindrical filter element, flows into the inner tube through the pores drilled in the inner tube 2, and the bottom of the inner tube 2, The filtrate is collected outside through the filtrate outlet nozzle 7.

If you want to start backwashing after filtration has been performed with a cylindrical filter element that is installed facing downwards, the cylindrical filter element is filled with droplets and the filtrate outlet nozzle (also backwash gas inlet) is It will be pressurized by washing gas. Here, the gas pressure is slowly transmitted from the pores of the inner cylinder 2 and the lower part of the inner cylinder to the outer cylinder of the cylindrical filter element, and the liquid remaining in the cylindrical filter element gradually oozes out from the outer cylinder 1 and is extracted to the outside. comes out. When the level of the residual liquid in the cylindrical filter element decreases, the backwashing gas finally acts evenly on the inner wall of the outer cylinder from the lower part of the cylinder, and the cake is smoothly peeled off.

(Example) Next, the present invention will be explained based on examples.

As shown in Fig. 1, an outer cylinder l (diameter D = 50 mm) and an inner cylinder 2 (diameter d
A cylindrical filter element having a length L = 700 mm and having a length L = 20 mm) was attached downward to perform filtration. That is, the pitch melted at about 300"C is charged through the stock solution charging nozzle 6, and after constant pressure filtration is performed at a pressure of 3 kg/cm", the residual liquid in the container 5 is extracted from the residual liquid extraction nozzle 8. I did a backwash.

Note that the backwashing gas was preheated N2 gas and introduced from the filtrate outlet nozzle (also serving as backwashing gas inlet) 7. Pressurization was carried out in two stages. That is, at first, low pressure (1 to 3 k
g/cm2) for several minutes, and when the draining was completed (sensed by a decrease in pressure), N2 gas was blown at a predetermined pressure. The amount of blowing was 6 i/- per surface area of the filter medium.

Table 1 below shows the results of processing by changing the backwash gas pressure and gas amount.

The gas pressure and gas amount in a relatively low pressure area to promote liquid removal is 1 to 3 kg/Cm2+ 25017
The fluid was drained smoothly at m2, and then 6 to 3 kg/cm”
.

By blowing relatively high pressure N2 gas of 65 to 1801/m'', the cake was peeled off smoothly.Also, even if the liquid could be drained in the low pressure range, if the high pressure blowing amount was insufficient, Experimental Example 3 As a result, the cake peeling was insufficient, and in the low pressure range, 4 kg/
It has been found that if a pressure of 1.5 cm or more is applied, the cake peels off unevenly during draining, and sufficient backwashing is not possible. ” ,
Preferably, the gas amount is less than 2 kg/cm" and 2501/m", and the pressurization in the high pressure region during backwashing is 6 kg/c- or more, and the gas amount is 61! /m” is considered to be the lower limit.

Table 2 below shows the backwashing results when using a conventional filter medium that does not have a double tube structure in the stopper example.

When the filter medium has a single-tube structure, backwashing when the filter medium is installed facing downwards causes the pressurized gas to act directly on the cake layer during draining, causing the cake to peel off from the top after draining, resulting in backwashing. Due to gas leakage, the cake peeled off unevenly and reliable backwashing was not possible.

(Effect of the invention) In the filtration and refining of high viscosity substances such as petroleum-based or coal-based pitch or polymers, by using the filtration device having a cylindrical filter element with a double-tube structure according to the present invention, cakes are eliminated during backwashing of the filter medium. The effect is that peeling can be performed smoothly and uniformly.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of a filtration device according to the present invention. 1... Outer cylinder (filter element filtration layer) 2...
Inner cylinder 3... Mounting screws 4... Tip cap 5... Filtration container 6... Stock solution inlet nozzle 7 Filtrate output nozzle (also serves as backwash gas port) 8... Residual liquid extraction nozzle (also serves as cake dispenser) Exit) Figure 1

Claims (1)

[Claims] 1. A cylindrical filter element with a fixed upper hanging type that can perform backwashing and regeneration after filtering a highly viscous substance with a viscosity of 10 to 5000 poise at 300°C and removing minute solids. A filtration device for high viscosity substances, comprising at least one cylindrical filter element, the cylindrical filter element having a double tube structure composed of an outer cylinder and an inner cylinder. . 2. The filtration device according to claim 1, wherein the outer cylinder of the cylindrical filter element forms a filtration layer, and a plurality of pores are provided in the side wall of the inner cylinder.