JPH02172506A - Method and apparatus for filtering material of high viscosity - Google Patents

Abstract

PURPOSE:To improve the rate of operation in a filtration process by surely drawing out liquids to be filtered held in filter materials to apply gases for back-washing uniformly and effectively to a filter-material wall, performing thereby back-washing and regeneration rapidly and surely. CONSTITUTION:In a filter container 1 provided with a raw-liquid-for-filtration inlet valve 3 and a cake-discharge valve 6, a plurality of cylindrical filter materials 2 with their upper ends being closed are mounted vertically on a header 8 made up of pipes, to which header 8 discharge pipes provided with a filtered liquid drawing-out valve 4 are connected so as to discharge the filtered liquids flowing from the inside of the container 1 into the header 8 to the outside of said container 1 from the lower section thereof. A gas feed pipe for back-washing of filter materials with a gas valve 5 for back-washing of filter materials is connected to the discharge pipes. As a result, filtered liquids held in the filter materials are surely drawn out and gases for back-washing are applied to the walls of filter materials uniformly and effectively, so that back- washing and regeneration can be performed rapidly and surely, achieving thereby an improved rate of operation in the filtration process.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to the field of manufacturing pitch for fibers in large quantities from petroleum-based or coal-based pitch, or the field of producing pitch for fibers in large quantities from petroleum-based or coal-based pitch, or the field of producing pitch for fibers in large quantities from petroleum-based or coal-based pitch, or for high-viscosity materials such as polymers (here, viscosity at 300°C). (100 Boies viscosity) can be used in the field of purification processing.

(Prior art) All conventional filtration methods are methods in which a cylindrical filter medium (filter element) is suspended from the top.
As in the filtration container 1 shown in FIG. 2 disclosed in Japanese Patent No. 3-150378, the stock solution is supplied from the lower part through the valve 3, the filtrate that has passed through the filter medium 2 is accumulated in the upper part, and the filtrate is collected through the filtrate extraction valve 4. In the case of backwashing, after extracting the raw solution in the filtration container, the filtrate in the filter medium is further extracted, and pressurized gas is blown from the backwashing gas cylinder 5 on the filtrate side to perform backwashing and regeneration. It is something to do. In this case, when filtrating low-viscosity substances such as water, the liquid inside the filter medium is easily drained as well as the liquid from the filter container, making it possible to backwash the liquid and causing no problem. 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, making it difficult to backwash the filter element when filtering high viscosity substances such as pitch. When extracting the stock solution in the filter 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 adhering to the outer wall of the filter medium will peel off, but in that state, the cake peeling will not proceed uniformly, and a peeled part and an adhered part will appear, which will cause the cake to peel off in the next step. The pressurized gas during washing does not act evenly on the adhered cake (this is because it leaks from the peeled portion of the cake), resulting in uneven cake peeling and insufficient regeneration.

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.

Therefore, an object of the present invention is to ensure that when filtering high viscosity substances such as pitch, the liquid in the filter element is reliably drained and the backwash gas acts more effectively on the wall of the filter element. The purpose of the present invention is to provide a technology that can increase the operating rate in a filtration process by performing backwashing and regeneration quickly and reliably.

(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. .

The present invention was made based on this knowledge, with the idea that the above object could be achieved by installing the filter medium upward in the filter container so that the filtrate could be drawn out at the bottom.

That is, when filtering a highly viscous substance to remove minute solids, the present invention applies a constant pressure or constant pressure to a filtration container in which a plurality of cylindrical filter media with a closed top end are vertically installed. Filtration is performed by introducing the filtrate downstream and guiding the filtrate through the hollow interior of each filter medium to the lower part of the filtration container. When backwashing is performed, the stock solution in the filtration container and the filtrate in the filter medium are extracted. The present invention relates to a method for filtrating a high viscosity substance, which is characterized in that backwashing and regeneration are performed by injecting backwashing gas into each filter medium.

In the method of the present invention, when backwashing is performed, the gas pressure should be 5 kg/cm2 or more, preferably 8 kg, because if the gas pressure is low, the peelability of the cake will decrease and the peeling will be uneven.
The gas amount is preferably 60J!10+" or more per filter medium surface area in order to uniformly remove the gas, and more preferably 65 N/m" to 200 I! , / m”.

Furthermore, the present invention provides a filtration device that can be used in such a method, in which a plurality of cylindrical filter media each having a closed top end are configured by pipes in a filtration container equipped with a filtration stock solution inlet valve and a cake discharge valve. The header is installed vertically on the header (filter media mounting pipe), and the header is equipped with a discharge pipe equipped with a filtrate withdrawal valve so that the filtrate inside the header that has flowed from inside the filter media can be discharged from the bottom of the filtration container to the outside of the filtration container. The present invention relates to a filtration device characterized in that a gas supply pipe for backwashing the filter medium is connected to the discharge pipe, and a gas supply pipe for backwashing the filter medium is connected to the discharge pipe.

In the filtration device of the present invention, the ladder has several filter media (3
The filter media can be attached to the hengoo using a screw-in method.

The header piping has an outer diameter comparable to that of the filter medium, and its projected area is made as small as possible to prevent cake from remaining in the filter container or hanging on a shelf after backwashing.

Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

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

A filter medium attachment tube (header) 8 assembled with piping having a diameter of 25 to 85 a+m is installed inside the filtration container body 1, and the filter medium 2 is screwed upward into the header. This filter medium is composed of a wire mesh consisting of three layers: a protective layer, a filtration layer, and a support layer.The nominal filtration accuracy is several microns, and the material is Su.
It is made by S. In addition, the top (tip) of the filter medium is attached to the filter medium support frame 7.
Fix the filter media so that they are spaced evenly apart. Each header blocks three to six filter media, and the filtrate passes through each header valve 9 and is recovered by the filtrate extraction valve 4. A backwashing gas inlet valve 5 is connected to the header valve.

To explain the process, a stock solution such as pitch is introduced into a filtration container 1 under a constant pressure or a constant flow rate through a filtration stock solution inlet valve 3, and is filtered by a filter medium 2, and the filtrate passes through a header 8 and a header valve 9, and then is It is recovered by the extraction valve 4. When backwashing and regenerating the filter medium 2, the valve 4 is closed, the backwashing gas valve 5 is opened, and the header valves 9 are sequentially opened and closed to perform backwashing and regeneration for each block.

(Example) Next, the present invention will be specifically explained using examples.

Implementation ■Soil A header (filter medium attachment pipe) constructed with a width of 50n + m in diameter inside a filtration container 1 with a diameter (D) of 450mm as shown in Figure 3.
8, with a diameter (d) of 50 mm and a length (L)
Eighteen filter media 2 of 9001III were attached by screwing upward. The filter media were arranged on two concentric circles, a small circle and a large circle, with 6 on the inside and 12 on the outside, with a mutual spacing of 45 mm or more. The filter medium attachment pipe 8 was a single collecting pipe to collect the filtrate to the outside, and a N2 gas blowing nozzle 5 was attached for backwashing the filter medium. Pitch melted at about 300°C was charged into this apparatus through the stock solution inlet valve 3, and constant pressure filtration was performed at a pressure of 3 kg/cta''.

In such filtration, the filtrate flowed downward through the filter medium, resulting in good fluidity and the filtrate was collected smoothly.

After filtration, the filtrate extraction valve 4 is closed, and preheated N2 gas is supplied from the backwashing gas valve 5 at a pressure of 8 kg/cm.
The adhering cake was removed by blowing at a blowing amount of 6517 m per surface area of the filter medium.

The cake was collected by opening the cake discharge valve 6 at the bottom of the filter container and discharging the cake to the outside. Some of the cake adhered to the header etc. in the filter container, but this cake can be removed by charging the heated solvent into the filter container, bubbling it with Ng gas, and then extracting it from the lower discharge valve 6. I was able to reliably recover it.

The process was carried out in the same manner as in Example 1, except that the backwash gas pressure and gas amount were changed. The results obtained are shown in Table 1.

Table 1 From Table 1, it can be seen that when the gas pressure was low, the peelability of the cake decreased, and when the gas pressure was less than 6 kg/cm2, the peeling became uneven. Although it was confirmed, it became non-uniform at 50Q/m2.

From the above 5, it was found that the gas pressure is preferably 6 kg/cm2 or more, more preferably 8 kg/cm'' or more, and the lower limit of the gas amount is considered to be 6042/m''.

Table 2 shows the backwashing results when the filter medium in Example 1 was oriented downward as in the filter device shown in FIG. 2.

Table 2 If the filter media is facing downward, it is difficult to remove the filtrate from the filter media.
Even if the gas amount was increased at a pressure of 8 kg/cub'', the cake peeled off unevenly and reliable backwashing was not possible.

(Effects of the Invention) As explained above, in the high viscosity substance filtration method and filtration device of the present invention, the filtrate inside the filter medium is reliably drained and the backwash gas acts uniformly and effectively on the filter medium wall. Therefore, backwashing and regeneration can be performed quickly and reliably, and the operating rate in the filtration process can be increased.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a filtration device as an example of the present invention, FIG. 2 is a sectional view of a conventional filtration device, and FIG. 3 is a perspective view of another filtration device of the invention. 1... Filter body 2... Filter medium (cylindrical filter element) 3...
Filtration stock solution inlet valve 4...Filtrate extraction valve 5...Gas valve for backwashing filter media 6...Cake discharge valve after backwashing 7...Filter media support frame 8...Filter media attachment pipe (Hesogu) 9.・Header valve

Claims (1)

[Claims] 1. When filtering a highly viscous substance to remove minute solids, the stock solution is placed under constant pressure in a filtration container in which a plurality of cylindrical filter media with a closed top end are vertically installed. Alternatively, filtration is performed by introducing the filtrate at a constant flow rate and guiding the filtrate through the hollow interior of each filter medium to the lower part of the filter container. When backwashing is performed, the undiluted solution in the filter container and the filter medium are A method for filtrating a high viscosity substance, characterized in that after extracting the filtrate, backwashing and regeneration are performed by injecting backwashing gas into each filter medium. 2. In a filtration device that can perform backwashing and regeneration quickly and reliably after filtration of high viscosity substances, multiple filters with closed tops are installed in a filtration container equipped with a filtration stock solution inlet valve and a cake discharge valve. A cylindrical filter medium is installed vertically on a header formed by a pipe, and the header is provided with a filtrate extraction valve so that the filtrate inside the header that has flowed from inside the filter medium can be discharged from the bottom of the filtration container to the outside of the filtration container. 1. A filtration device, characterized in that a discharge pipe is connected to the exhaust pipe, and a gas supply pipe for backwashing the filter medium is connected to the discharge pipe, and the gas supply pipe is connected to the discharge pipe. 3. The filtration device according to claim 2, wherein the header is divided into blocks for every number of filter media, and the discharge pipe is connected to each block.