JP2005296757A - Filter cleaning device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous-filter cleaning device with a small drainage amount. <P>SOLUTION: The filter cleaning device is equipped with a cleaning solution transfer section (12, 13) for forcing a cleaning solution into a filter element (2) from its downstream side, a pressure adjusting section (9, 10) for controlling the pressure of the cleaning solution splashed on the filter element (2), a flowmeter for measuring the flow rate of the cleaning solution forced into the filter element (2), and an arithmetic unit (14) which calculates a fouling factor K and judges the state of cleaning of the filter element (2) on the basis of the fouling factor K. The fouling factor K is calculated by the formula: K=(P/Q)×A/μ (wherein P and Q are the pressure and flow rate of the cleaning solution, respectively; A is the filtration area of the filter element (2); and μ is the viscosity coefficient of the cleaning solution). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a filter cleaning device, and more particularly to a filter element cleaning device that removes dust by filtering dust-containing gas through a porous filter.

  2. Description of the Related Art Porous (porous) filters that remove dust by filtering porous gas using porous ceramic or metal are used. An overview of the porous filter in operation is described with reference to FIG.

A plurality of filter elements 2 are installed on the filter tube plate 5 in the pressure vessel 1. The filter element 2 has a cylindrical shape (including a hollow cylindrical shape, a box shape, and a cone), and has an opening at the top, a hole in the filter tube plate 5 and a gap between the filter tube plate 5 and gas bypass. Installed so as not to.
The filter element 2 is made of a porous material typified by ceramic or metal, and dust is filtered and removed when dust-containing gas passes through the holes.

During operation, the dust-containing gas is injected from the dust-containing gas inlet nozzle 3, and the dust-containing gas is removed through the filter element 2 and is discharged from the clean gas outlet nozzle 4 as a clean gas. At this time, dust adheres to the outer surface of the filter element.
When a porous filter is used for a long time, the adhering dust increases, the holes are clogged, and the pressure loss increases, so it is necessary to periodically clean the filter element

During operation, a method of backwashing with a high-pressure inert gas from the downstream side of the filter element 2 may be taken. However, the cleaning of the filter element 2 for fundamentally restoring the capacity of the increase in pressure loss due to clogging over time during operation is performed when the operation is stopped.
As a typical cleaning method, there is a method in which the manhole 6 is opened, the filter element 2 is removed, and the pressure vessel 1 is cleaned with a cleaning liquid. Most inexpensively, water is used as the cleaning liquid. Depending on the adhered substance, a cleaning solution for removing the adhered substance is used.

Since removing the filter element 2 is laborious, a method of cleaning without removing the filter element 2 may be employed. A conventional method for cleaning without removing the filter element 2 is shown in FIG.
The cleaning jig 8 is attached to the upper part of the filter element 2, and the cleaning liquid is made to flow from the downstream side (clean) side of the filter in normal operation by the cleaning liquid pump 13, thereby removing the dirt on the filter element 2. The cleaning liquid after cleaning is discharged from the drain nozzle 7 to the drain tank.
As the cleaning liquid, it is preferable to use a liquid that has a higher density and viscosity than gas and has a cleaning effect.
An invention relating to a cleaning liquid is disclosed in Patent Document 1.
Further, Patent Document 2 discloses a method for improving the cleaning power in combination with a high-pressure gas.
JP-A-5-309221 JP-A-5-285354

In order to sufficiently clean the filter element and reduce the cost required for cleaning the filter element, it is important to accurately detect when the cleaning should be finished. Continuing the cleaning despite the sufficient cleaning being performed increases the amount of waste water generated and the amount of cleaning liquid necessary for the cleaning, and increases the cost of cleaning. On the other hand, it is not preferable to end the cleaning of the filter element 2 in spite of insufficient cleaning.
It is desirable to provide a technique for accurately knowing when to finish cleaning the filter element.

  An object of the present invention is to provide a technique for accurately knowing when the cleaning of a filter element should be finished.

  In order to achieve the above object, the present invention employs the following means. In order to clarify the correspondence between the description of [Claims] and the description of [Best Mode for Carrying Out the Invention], the technical matters included in the means include [for carrying out the invention]. The number / symbol used in the best form] is added. However, the added numbers and symbols shall not be used for the interpretation of the technical scope of the invention described in [Claims].

In one aspect, the filter cleaning apparatus according to the present invention controls a cleaning liquid transfer section (12, 13) for press-fitting cleaning liquid from the downstream side of the filter element (2), and a pressure of the cleaning liquid applied to the filter element (2). A contamination coefficient K is calculated on the basis of the pressure and the flow rate, a pressure meter (9, 10), a flow meter for measuring the flow rate of the cleaning liquid press-fitted into the filter element (2), and the contamination And an arithmetic unit (14) for determining the cleaning situation of the filter element (2) based on a coefficient K. The contamination coefficient K is expressed by the following formula (1) expressed using the pressure P, the flow rate Q, the filtration area A of the filter element (2), and the viscosity coefficient μ of the cleaning liquid:
K = (P / Q) · A / μ, (1)
Is calculated by

  The contamination coefficient K calculated using the equation (1) is a good index indicating the degree of progress of cleaning the filter element (2). Since the filter cleaning apparatus determines the cleaning situation of the filter element (2) using the contamination coefficient K, it is possible to accurately grasp whether or not the cleaning should be completed.

  The arithmetic unit (14) preferably generates a cleaning end output indicating that the cleaning of the filter element (2) has ended when the contamination coefficient K becomes smaller than a predetermined threshold.

  The present invention provides a technique for accurately knowing when the cleaning of the filter element should be finished.

DESCRIPTION OF EMBODIMENTS Embodiments of a porous filter cleaning device according to the present invention will be described below with reference to the accompanying drawings.
The porous filter of the present embodiment is installed upstream of the gas turbine in the process of supplying the combustion gas generated by incomplete combustion of coal to the gas turbine in the coal gasification combined power generation apparatus, and removes dust in the combustion gas. However, the present invention is not limited to this type.

1. Configuration of Porous Filter Cleaning Device The outline of the porous filter cleaning according to the first embodiment will be described with reference to FIG.
The porous filter includes a pressure vessel 1, a filter element 2, a dust-containing gas inlet nozzle 3, a clean gas outlet nozzle 4, a filter tube plate 5, a manhole 6, and a drain nozzle 7.

  The pressure vessel 1 is a container for the outer shell of a porous filter, and is manufactured to withstand internal pressure. FIG. 1 shows a vertical pressure vessel in which the upper head portion has a flat hemispherical shape, the barrel portion has a cylindrical shape, and the lower head portion has a conical shape with a downward direction. The shape is not limited.

  The filter element 2 is made of a porous material typified by ceramic or metal, and has a cylindrical shape (including a hollow cylindrical shape, a box shape, and a conical shape). The filter element 2 is attached to the hole of the filter tube plate 5 with the opening portion at the top so that a gap is formed between the filter element 2 and the dust-containing gas. When the dust-containing gas passes from the outside to the inside of the filter element 2 through the pores, the dust is filtered and removed.

  During operation, the dust-containing gas is injected from the dust-containing gas inlet nozzle 3, and the clean gas filtered by the filter element 2 is discharged from the clean gas outlet nozzle 4.

  The filter tube plate 5 is a plate having a body cross-sectional shape installed so as to divide the inside of the pressure vessel 1 horizontally. A space between the filter tube plate 5 and the inner wall of the pressure vessel 1 is sealed by welding or packing. The filter tube plate 5 is provided with a hole for attaching the filter element 2. The filter tube plate 5 is installed so as to withstand the weight of the filter element 2 or the pressure difference generated in the filter element 2.

The manhole 6 is an opening for allowing a person to enter the tank for maintenance while the porous filter is stopped, or for carrying the cleaning jig 8 and the cleaning liquid pipe 12 into the porous filter. The removed filter element may be carried out / in from the manhole 6. The manhole 6 is closed with a manhole cover during operation.
In FIG. 1, the manhole 6 is attached to the top portion of the head, but is not limited to the top portion as long as it is above the filter tube sheet 5.

  The drain nozzle 7 is a nozzle for discharging the cleaning liquid (drain liquid) after cleaning. For drainage, the drain nozzle 7 is usually installed at the lowermost part of the pressure vessel 1.

  The porous filter cleaning device includes a cleaning jig 8, a pressure gauge 9, a regulating valve 10, a flow meter 11, a cleaning liquid pipe 12, a cleaning liquid pump 13, and an arithmetic unit 14.

The cleaning liquid pump 13 and the cleaning jig 8 are connected by a cleaning liquid pipe 12.
An adjustment valve 10 is set in the middle of the cleaning liquid pipe 12. A pressure gauge 9 is set downstream of the regulating valve 10. A flow meter 11 is installed on the cleaning liquid pipe 12.

The cleaning jig 8 is a jig for connecting the cleaning liquid pipe 12 and the filter element 2. The cleaning jig 8 is installed so that the cleaning liquid flows from the downstream side (clean side / inside) to the filter element 2. The cleaning jig 8 is attached so that the cleaning liquid does not leak from between the filter element 2 or the filter tube plate 5 even when a predetermined pressure is applied. The cleaning jig 8 may have a shape that covers all the filter elements 2 or a shape that allows the cleaning liquid to flow through a plurality of or one filter element 2. In the case of a shape in which the cleaning liquid is allowed to flow through the plurality of filter elements 2, the connection portion of the cleaning jig 8 with the filter element 2 may be branched so as to be connected to each filter element 2, or can be supplied to the plurality of filter elements 2. Shape may be sufficient.
The number of filter elements 2 to be cleaned at a time is related to the capacity of the cleaning liquid pump 13, the pressure to be cleaned, and the size of the filter element 2.

  The pressure gauge 9 detects the pressure of the cleaning liquid that is press-fitted into the filter element 2. The pressure signal is transmitted to the regulating valve 10 and the arithmetic device 14.

  The adjustment valve 10 adjusts the flow rate of the cleaning liquid based on a signal from the pressure gauge 9 so that the pressure of the cleaning liquid press-fitted into the filter element 2 becomes the set pressure instructed by the arithmetic unit 14.

  The flow meter 11 measures the flow rate of the cleaning liquid. The flow rate signal is transmitted to the computing device 14.

  The cleaning liquid pipe 12 is a pipe that connects the cleaning liquid pump 13 and the cleaning jig 8 to transfer the cleaning liquid. A pressure gauge 9, a regulating valve 10, and a flow meter 11 are installed in the middle of the cleaning liquid pipe 12.

  The cleaning liquid pump 13 is a pump for press-fitting the cleaning liquid into the filter element 2. As long as the cleaning liquid can be injected at a target pressure, the pump is not limited to a pump, and a cleaning liquid tank installed at a high place can also be used.

  The arithmetic device 14 determines a set pressure of the cleaning liquid that is press-fitted into the filter element 2 and transmits the determined pressure to the regulating valve 10. Further, the arithmetic unit 14 receives information on the pressure information detected by the pressure gauge 9 and the flow rate measured by the flow meter 11, calculates the contamination coefficient K of the filter element 2, and determines that the cleaning is completed. To do. The method for calculating the contamination coefficient K will be described in detail later.

  The drainage tank 15 is a container for storing the drainage discharged from the porous filter.

2. Cleaning operation The porous filter cleaning device described above cleans the filter element 2 while actively controlling the pressure of the cleaning liquid applied to the filter element 2. Usually, the pressure of the cleaning liquid is not controlled at the time of cleaning, and cleaning may continue even if the pressure becomes ineffective for cleaning. Specifically, at the start of cleaning with much dirt, the pressure loss of the filter element 2 is high so that the pressure of the cleaning liquid is high. The pressure drops. Even if the cleaning is continued as it is, since the pressure is reduced, the pressure applied to the pores of the filter element 2 is reduced in the portion where the dirt is not removed, and at the same time, the speed of the cleaning liquid passing through the pores is reduced. For this reason, the cleaning effect is reduced. If the cleaning is continued as it is, the amount of the cleaning liquid to be used increases.

  As described above, the cleaning effect of the cleaning liquid has a correlation with the pressure of the cleaning liquid applied to the pores of the filter element 2 and the flow rate of the cleaning liquid through the pores. That is, in the backwashing of the porous filter as in the present embodiment, the dirt clogged in the pores is removed by applying pressure, and at the same time, the dirt is washed away with a cleaning liquid having an effective flow rate in the pores. Therefore, effective cleaning cannot be performed unless a pressure higher than the effective pressure is applied.

The arithmetic unit 14 determines the pressure effective for cleaning as follows.
First, the pressure of the cleaning liquid is gradually increased by the adjusting valve 10 within a range of the allowable pressure of the filter element 2 or the like. Normally, if the pressure loss of the filter element 2 is substantially constant, the value of the pressure gauge 9 and the value of the flow meter 11 change with correlation.
If dirt is removed at a certain pressure, the pressure loss is changed, the relationship between the value of the pressure gauge 9 and the value of the flow meter 11 is changed, and the flow rate change is increased with respect to the pressure change. The computing device 14 determines that the pressure when the flow rate is large relative to the pressure change is a pressure with high cleaning efficiency, and maintains the pressure or a pressure determined based on the pressure. In this way, the computing device 14 can determine a pressure effective for cleaning.

  As described above, the cleaning device according to the present embodiment has a degree of contamination of the filter element 2 that changes during cleaning (a portion clogged with a pore, a portion that penetrates the pore, and a stain around the pore due to contamination. The effective pressure is maintained regardless of the size of the small area, etc., and the pressure of the cleaning liquid and the flow velocity at the pores are applied.

  Furthermore, in this embodiment, by maintaining the pressure effective for cleaning, cleaning is performed at a pressure having a higher cleaning effect, and effective cleaning is performed, thereby reducing the amount of cleaning liquid used. it can.

3. Determination of Completion of Cleaning The arithmetic unit 14 calculates the contamination coefficient K of the filter element 2 using the cleaning liquid pressure P detected by the pressure gauge 9 and the cleaning liquid flow rate Q measured by the flow meter 11, and is calculated. Using the dirt coefficient K, it is determined that the cleaning has been completed to the target state. Specifically, the soil coefficient K is expressed by the following formula (1):
K = (P / Q) · A / μ, (1)
Is calculated by Here, A is the filtration area of the filter element 2, and μ is the viscosity coefficient of the cleaning liquid.

  Determining the completion of cleaning of the filter element 2 according to the ratio of the cleaning liquid pressure P to the cleaning liquid flow rate Q is effective for determining whether or not the cleaning should be completed more accurately. This is because the ratio of the cleaning liquid pressure P to the cleaning liquid flow rate Q is a good index indicating whether or not cleaning is in progress. If the filter element 2 is dirty, the cleaning liquid pressure P becomes higher with a smaller cleaning liquid flow rate Q, so the ratio P / Q of the cleaning liquid pressure P to the cleaning liquid flow rate Q increases. As the removal of the dirt of the filter element 2 proceeds, the ratio P / Q of the cleaning liquid pressure P to the cleaning liquid flow rate Q decreases. By determining the completion of cleaning of the filter element 2 using the ratio P / Q showing such a property, an accurate determination can be made.

As understood from the equation (1), the contamination coefficient K is proportional to the ratio P / Q of the cleaning liquid pressure P to the cleaning liquid flow rate Q. Accordingly, as shown in FIG. 2, as the cleaning progresses, the ratio P / Q of the cleaning liquid pressure P to the cleaning liquid flow rate Q decreases. Therefore, the contamination coefficient K proportional to the ratio P / Q is also an overall tendency. As it decreases. The soil coefficient K having such properties is expressed by the following conditional expression (2):
K ≦ K _TH ,
Is satisfied, the arithmetic unit 14 determines that the cleaning is completed. Here, K _TH is a predetermined threshold value and is determined so that the dirt is sufficiently removed. When the arithmetic unit 14 determines that the cleaning is completed, the arithmetic unit 14 generates a cleaning completion output indicating that the cleaning is completed. Specifically, the arithmetic device 14 displays a cleaning completion message on a display device (not shown). Alternatively, or in addition, the computing device 14 can generate a sound indicating that the cleaning is complete.

  The filtration area A of the filter element 2 in the equation (1) is a factor introduced to determine the completion of cleaning more accurately. Regardless of the progress of cleaning, if the filtration area A of the filter element 2 increases, the cleaning liquid flow rate Q increases. In order to cancel this effect, the ratio P / Q is multiplied by the filtration area A in the calculation of the contamination coefficient K. Multiplying the filtration area A is equivalent to obtaining the cleaning liquid flow rate per unit area of the filter element 2 and determining the contamination coefficient K according to the cleaning liquid flow rate per unit area.

  The reciprocal 1 / μ of the viscosity coefficient μ of the cleaning liquid in the equation (1) is also a factor introduced to determine the completion of cleaning more accurately. If the viscosity coefficient μ of the cleaning liquid increases, the cleaning liquid pressure P increases regardless of the progress of cleaning. In order to cancel this effect, the ratio P / Q is multiplied by the reciprocal of the viscosity coefficient μ in the calculation of the contamination coefficient K.

  As explained above, the contamination coefficient K, which is proportional to the ratio P / Q of the cleaning liquid pressure P to the cleaning liquid flow rate Q and the filtration area A of the filter element 2 and inversely proportional to the viscosity coefficient μ of the cleaning liquid, is calculated. By determining that the cleaning is completed using the coefficient K, the completion of the cleaning can be accurately detected.

It should be noted that the conditional expression (2) used for the arithmetic unit 14 to determine that the cleaning is completed can be changed in various ways. For example, the arithmetic unit 14 calculates an evaluation coefficient K ′ (= 1 / K) that is the reciprocal of the dirt coefficient K, and when the evaluation coefficient K ′ becomes smaller than a predetermined threshold value K _TH ′, the cleaning is completed. It is possible to judge that

4). Other Embodiments As shown in FIG. 3, the cleaning liquid pipe 12 can be directly connected to the manhole 6 without using the cleaning jig 8. In this case, the clean gas outlet nozzle 4 is partitioned. Such an embodiment has an advantage that the operation is easy because it is not necessary for a person to enter the porous filter and attach the cleaning jig 8. The embodiment of FIG. 4 is particularly suitable when the capacity of the cleaning liquid pump 13 is sufficient or when the porous filter is small.

  The cleaning liquid pipe 12 is connected not only to the manhole 6 but also to a clean gas outlet nozzle.

In the above two embodiments, as a porous filter using the porous filter cleaning device of the present invention, a porous filter for dust removal of combustion gas of a coal gasification combined power generation device is exemplified, but this type of porous filter However, the present invention can be applied to any filter that performs filtration using a filter element and a filter medium that can withstand a constant backwash pressure.
Specifically, the present invention can be applied to a dust removal filter for pressurized fluidized bed, a candle type porous filter for dust removal, and the like.

  Furthermore, the method of cleaning the filter element 2 while keeping the pressure of the cleaning liquid constant can be applied even when the filter element 2 is removed from the porous filter body for cleaning.

It is a schematic diagram of one embodiment of porous filter washing of the present invention. It is a graph explaining the judgment method which judges the time of completion | finish of washing | cleaning using the soil coefficient K. FIG. It is a schematic diagram of other forms of implementation of porous filter washing of the present invention. It is an outline figure at the time of operation of a porous filter. It is an outline figure of washing of the conventional porous filter.

Explanation of symbols

1 Pressure Vessel 2 Filter Element 3 Dust Gas Inlet Nozzle 4 Clean Gas Outlet Nozzle 5 Filter Tube Plate 6 Manhole 7 Drain Nozzle 8 Cleaning Jig 9 Pressure Gauge 10 Adjusting Valve 11 Flowmeter 12 Cleaning Fluid Piping 13 Cleaning Fluid Pump 14 Arithmetic Unit 15 Exhaust Aquarium

Claims (2)

A cleaning liquid transfer section for press-fitting cleaning liquid from the downstream side of the filter element;
A pressure adjusting unit that controls the pressure of the cleaning liquid applied to the filter element;
A flow meter for measuring the flow rate of the cleaning liquid press-fitted into the filter element;
A calculation unit that calculates a contamination coefficient K based on the pressure and the flow rate, and that determines the cleaning status of the filter element based on the contamination coefficient K;
The contamination coefficient K is expressed by the following formula (1) expressed using the pressure P, the flow rate Q, the filtration area A of the filter element, and the viscosity coefficient μ of the cleaning liquid:
K = (P / Q) · A / μ, (1)
Calculated by the filter cleaning device. The filter cleaning apparatus according to claim 1,
The arithmetic unit is a filter cleaning device that generates a cleaning end output indicating that the cleaning of the filter element has ended when the contamination coefficient K becomes smaller than a predetermined threshold value.

Images