JP2009056354A - Dust shakedown control method of high-temperature dust collector and dust shakedown control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent the clogging of a ceramic filter while suppressing the temperature drop of a combustion gas. <P>SOLUTION: The temperature of the combustion gas at the inlet of a high-temperature dust collector 3 is detected by a temperature detector 16 and, when the detected temperature of the combustion gas becomes a preset predetermined temperature or above, a predetermined amount of compressed air is blown in the ceramic filter of the high-temperature dust collector 3 from a compressed air supply device 5 to shake down the dust adhered to the surface of the ceramic filter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dust removal control method and a control device for a high-temperature dust collector that removes dust in a high-temperature combustion gas generated by combustion of waste by a cylindrical ceramic filter.

  As a dust collector that collects high-temperature combustion gas generated in a waste incinerator or incineration ash melting furnace, a high-temperature dust collector using a heat-resistant cylindrical ceramic filter is used ( Patent Document 1). Since the ceramic filter can be used even in a high-temperature atmosphere due to its characteristics, the ceramic filter can be installed upstream of the boiler. In this way, by removing dust in the combustion gas upstream of the boiler, dust adhesion to the boiler can be suppressed, corrosion of the superheated tube can be prevented, and the boiler steam temperature can be increased, thereby improving the heat recovery efficiency. Can be improved.

  By the way, in this type of high-temperature dust collector, high-temperature combustion gas containing dust is supplied from the outside of the cylindrical ceramic filter, and dust is removed and purified by a ceramic layer having pores of the ceramic filter. Gas is exhausted through the inner space of the ceramic filter. Since it is such a dust removal mechanism, if the combustion gas is circulated continuously, dust adheres and accumulates on the outer surface of the ceramic filter and clogs the pores. By supplying compressed air to the inner space (reverse cleaning), dust is removed (see Patent Document 2).

  FIG. 4 shows a system configuration diagram of a conventional dust removal control device. As shown in the figure, a high-temperature dust collector 53 having a ceramic filter is installed in the combustion gas passage 51 of the incinerator 50 on the upstream side of the boiler 52. A compressed air supply device 54 is connected to the high temperature dust collector 53, and compressed air is supplied from the compressed air supply device 54 to the inner space of the ceramic filter by a command signal from the control device 55. Further, a differential pressure detecting device 56 for calculating the differential pressure between the inlet side and the outlet side of the high temperature dust collecting device 53 is provided. Based on a signal from the differential pressure detecting device 56, the control device 55 detects the differential pressure. When the predetermined value is exceeded, it is determined that the ceramic filter is clogged, and a command signal is transmitted to the compressed air supply device 54 to supply compressed air for backwashing the filter.

  However, the conventional dust removal control device supplies compressed air when the differential pressure between the inlet side and the outlet side of the high-temperature dust collector 53 increases, in other words, when the filter is clogged. Therefore, there is a case where dust clogged in the filter cannot be effectively removed, and it is necessary to increase the amount of compressed air, increase the compressed air pressure, or increase the supply frequency. When the amount of air for dust removal, the number of times of dust removal, etc. are increased in this way, the combustion gas temperature decreases, and the heat recovery efficiency in the boiler 52 disposed downstream of the high temperature dust collector 53 decreases. There is a problem that it will.

JP 2001-108216 A JP 2001-179024 A

  The present invention has been made in view of the above-described problems, and dust removal of a high-temperature dust collector that can effectively prevent clogging of a ceramic filter while suppressing a decrease in combustion gas temperature. It is an object of the present invention to provide a control method and a control device.

  The present inventors have found that clogging of the ceramic filter at the outlet of the incinerator is caused by the action of components such as Na, K, and Ca contained in dust and fume in the combustion gas. Alkali metals such as Na, K, and Ca, and chlorides of alkaline earth metals have a low melting point, and therefore melt as the combustion gas temperature increases. The molten chloride or the like enters and adheres to the pores of the ceramic filter, causing clogging of the pores. For these reasons, the present inventors have obtained the knowledge that clogging of the ceramic filter depends on the inlet temperature of the high temperature dust collector, and have completed the present invention.

In short, in order to achieve the above object, the dust removal control method of the high-temperature dust collector according to the first invention is:
In a high-temperature dust collector that removes dust in high-temperature combustion gas with a cylindrical ceramic filter,
When the combustion gas temperature at the inlet of the high-temperature dust collector is detected and the detected combustion gas temperature is equal to or higher than a predetermined temperature, the compressed air having a predetermined amount and a predetermined pressure is placed inside the ceramic filter. The dust adhering to the surface of the ceramic filter is blown off.

The dust removal control device for the high-temperature dust collector according to the second invention is
In a high-temperature dust collector that removes dust in high-temperature combustion gas with a cylindrical ceramic filter,
(A) compressed air supply means for blowing compressed air into the ceramic filter;
(B) temperature detection means for detecting the combustion gas temperature at the inlet of the high-temperature dust collector;
(C) storage means for storing data indicating the relationship between the combustion gas temperature at the inlet of the high-temperature dust collector and the amount of compressed air supplied from the compressed air supply means, the compressed air pressure, and the number of times of compressed air supply;
(D) When the combustion gas temperature detected by the temperature detection means is equal to or higher than a predetermined temperature set in advance, the compressed air amount, compressed air pressure and compressed air supply frequency data corresponding to the combustion gas temperature are And a control means for calculating a command value by reading from the storage means and controlling the compressed air supply means based on the command value.

  According to the first and second inventions, the amount of compressed air, the compressed air pressure, and the number of times compressed air is supplied to remove dust adhering to the surface of the ceramic filter in accordance with the combustion gas temperature at the inlet of the high temperature dust collector. Therefore, the amount of compressed air, compressed air pressure, and the number of times of compressed air supply are appropriately controlled to effectively suppress clogging of the ceramic filter and to suppress a decrease in combustion gas temperature due to compressed air supply. As a result, the reduction in the heat recovery rate can be further suppressed as compared with the conventional one. Moreover, since the compressed air supply means can be operated efficiently, power and electricity consumption can also be reduced.

  Next, specific embodiments of a dust removal control method and a control device for a high-temperature dust collector according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a system configuration diagram of a dust removal control device for a high-temperature dust collector according to an embodiment of the present invention, and FIG. 2 shows a partial cross-sectional view of the high-temperature dust collector of this embodiment. Has been.

  As shown in FIG. 1, in this embodiment, a high-temperature dust collector 3 having a ceramic filter is installed in the combustion gas passage 2 of the incinerator 1, and a boiler 4 is disposed downstream of the high-temperature dust collector 3. Is installed. A compressed air supply device (corresponding to “compressed air supply means” of the present invention) 5 is connected to the high temperature dust collector 3, and the ceramic filter in the high temperature dust collector 3 is supplied from the compressed air supply device 5 when necessary. Is supplied with backwash air.

  As shown in FIG. 2 (the whole figure is omitted), the high-temperature dust collector 3 includes an outer cylinder 6 having a cylindrical body, and an inner cylinder provided concentrically inside the outer cylinder 6. 7, an inner space 8 surrounded by the outer cylinder 6 and the inner cylinder 7 is defined in the casing, and a gas inlet for introducing combustion gas (exhaust gas) is provided above the inner space 8. In addition to being provided, a hopper for collecting and discharging dust is provided below the internal space 8. In addition, a gas outlet for deriving clean gas is provided above the inner space 9 of the inner cylinder 7.

  A plurality of (only one is shown in FIG. 2) cylindrical ceramic filters 10 are suspended between the outer cylinder 6 and the inner cylinder 7. These ceramic filters 10 are arranged radially in the upper and lower stages with the central axis of the inner cylinder 7 as the center.

  Each ceramic filter 10 has one end fitted into and fixed to a through hole 11 drilled in the outer cylinder 6, and the other end is somewhat of the gas passage port 12 drilled in the inner cylinder 7. The outer end portion having a large diameter is fitted and fixed and supported. The diameter of the gas passage port 12 is substantially the same as the inner diameter of the ceramic filter 10.

  A backwash air blowing port 13 is provided at one end of the ceramic filter 10, and a tip of a backwash air blowing tube 15 branched from the pulse tube 14 is inserted into the backwash air blowing port 13. ing.

  In this way, when the ceramic filter 10 is backwashed, compressed air is supplied to the pulse tube 14, so that compressed air (reverse backflow) enters the ceramic filter 10 from the backwash air blowing tube 15 through the backwash air inlet 13. Washing air) is ejected, and dust attached to the outer surface of the ceramic filter 10 is removed. Note that the backwash air travels straight and flows to the gas passage port 12, and at that time, the flow rate is reduced, and a rapid pressure drop does not occur, and the required pressure is maintained inside the ceramic filter 10.

  Returning to the system configuration diagram of FIG. 1, the combustion gas passage 2 on the inlet side of the high-temperature dust collector 3 has a temperature detector that detects the temperature of the combustion gas passing through the combustion gas passage 2 (“temperature” of the present invention). (Corresponding to “detection means”) 16 is installed, and a temperature detection signal detected by the temperature detector 16 is transmitted to the control device 17. The control device 17 stores a calculation unit (corresponding to the “control unit” of the present invention) 17a that performs a required calculation based on an input signal or the like and outputs a command signal, data necessary for the calculation, a required program, and the like. And a memory (corresponding to the “storage means” of the present invention) 17b. The calculation unit 17a of the control device 17 performs a required calculation described later, a command signal is transmitted to the compressed air supply device 5 based on the calculation result, and the compressed air supply device 5 is operated.

  By the way, according to the study by the present inventors, clogging of the ceramic filter at the incinerator outlet is caused by melting of chlorides such as Na, K and Ca contained in dust and fume in the combustion gas. It was found that it was caused by intruding into and adhering to the pores. Since alkali metal and alkaline earth metal chlorides such as Na, K, and Ca have a low melting point, they melt as the combustion gas temperature increases, so clogging of the ceramic filter depends on the inlet temperature of the high-temperature dust collector. It is thought to do. Therefore, data (or a relational expression) for preventing clogging of the ceramic filter 10 due to dust is preset and stored in the memory 17b of the control device 17 based on the relationship between the combustion gas temperature and the melting point of dust and fume. By setting it, it becomes possible to drive the compressed air supply device 5 effectively.

  In the present embodiment, as data (or an arithmetic expression) for compressed air supply control, as shown in FIG. 3, the amount of compressed air (L / L) per ceramic filter corresponding to the combustion gas temperature (° C.). The data of the compressed air pressure (MPa) and the number of times of supply (times / h) are stored in the memory 17b, and the data in the memory 17b is referred to based on the combustion gas temperature detected by the temperature detector 16. Then, the calculation unit 17 a calculates the necessary compressed air amount, compressed air pressure, and the number of times of supply, and transmits a command signal to the compressed air supply device 5.

  Here, since the data (or arithmetic expression) shown in FIG. 3 changes according to the waste quality (calorific value, moisture, etc.) put into the incinerator 1, the memory 17b corresponds to the waste quality. A plurality of data is stored.

  Since the dust removal control device of the high-temperature dust collector of the present embodiment is configured as described above, the air amount, air pressure, and number of times of supply of compressed air supplied into the cylindrical ceramic filter 10 are appropriately controlled. Accordingly, clogging of the ceramic filter 10 can be effectively suppressed, and a decrease in the combustion gas temperature due to the supply of compressed air can be suppressed. Therefore, not only can the decrease in the heat recovery rate be suppressed, but also the compressed air supply device 5 can be operated efficiently, so that the power and the amount of electricity used can be reduced. ing.

The system block diagram of the dust removal control apparatus of the high temperature dust collector which concerns on one Embodiment of this invention. Partial sectional view of the high temperature dust collector of this embodiment Graph showing the relationship between combustion gas temperature, compressed air volume, compressed air pressure, and number of supply System configuration diagram of a conventional dust removal control device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Incinerator 2 Combustion gas passage 3 High temperature dust collector 4 Boiler 5 Compressed air supply device 6 Outer cylinder 7 Inner cylinder 10 Ceramic filter 13 Backwash air blowing port 14 Pulse tube 15 Backwash air blowing tube 16 Temperature detector 17 Control device 17a arithmetic unit 17b memory

Claims (2)

In a high-temperature dust collector that removes dust in high-temperature combustion gas with a cylindrical ceramic filter,
When the combustion gas temperature at the inlet of the high-temperature dust collector is detected and the detected combustion gas temperature is equal to or higher than a predetermined temperature, the compressed air having a predetermined amount and a predetermined pressure is placed inside the ceramic filter. A dust removal control method for a high-temperature dust collector, wherein dust attached to the surface of the ceramic filter is removed by blowing air. In a high-temperature dust collector that removes dust in high-temperature combustion gas with a cylindrical ceramic filter,
(A) compressed air supply means for blowing compressed air into the ceramic filter;
(B) temperature detection means for detecting the combustion gas temperature at the inlet of the high-temperature dust collector;
(C) storage means for storing data indicating the relationship between the combustion gas temperature at the inlet of the high-temperature dust collector and the amount of compressed air supplied from the compressed air supply means, the compressed air pressure, and the number of times of compressed air supply;
(D) When the combustion gas temperature detected by the temperature detection means is equal to or higher than a predetermined temperature set in advance, the compressed air amount, compressed air pressure and compressed air supply frequency data corresponding to the combustion gas temperature are A dust removal control device for a high-temperature dust collector, comprising: a control unit that reads out from a storage unit, calculates a command value, and controls the compressed air supply unit based on the command value.

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