JP2001323286A - Deposited ash prediction system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system intended to grasp initial deposited ash status and predict the ash deposition progress on e.g. the surface of a heat-transfer tube. SOLUTION: This system is such one as to be installed on a gasifier furnished with an equipment made up of a gasification furnace 13 for gasifying a carbonaceous fuel 17 such as coal to produce the resulting gas, a gas cooler 14 for cooling the gas thus produced and recovering heat, and a dust collector for removing ash 10 in the gas thus cooled, and be composed of an electroconductivity measuring device 3 for ash 10 deposited on a heat-transfer tube 18 or a filter element, or the like, in the above equipment and a soot blow nozzle 12 as a means for removing the ash 10 thus deposited. The system works as follows: by the aid of the electroconductivity measuring device 10, the change in the measurements with time is recorded on a chart as shown in the figure 2, and based on the record, the ash deposition progress is predicted, and in response to the prediction, a removing means such as the soot blow nozzle 12 is operated under control under the condition set in advance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the prediction of deposited ash adhering to equipment such as gasification equipment, and more particularly, to measure the conductivity of the deposited ash to predict the progress of the deposited ash and control the removal device. The present invention relates to a fouling ash prediction system.

[0002]

2. Description of the Related Art Carbon-containing fuel represented by coal is an important energy source with abundant reserves,
Ash (alumina, silica, calcium, etc.) and harmful metals (Cr, Hg, etc.), the treatment method was difficult and narrowed the applicable range. However, in spouted bed coal gasifiers, coal is partially burned at high temperatures with a gasifying agent such as oxygen to generate useful gas, and ash is melted out to remove harmful components from the system as slag that is difficult to elute. be able to. For this reason, the field of application has been expanded, and it is particularly promising as a fuel for power generation equipment or a raw material for industrial equipment.

FIG. 5 shows a conventional gasification system. In this system, the ash 10 containing unburned carbon generated in the gasifier 13 is cooled together with the generated gas 16 via the gas cooler 14 and then cooled by the cyclone 15.
Then, the dust is removed by the dust collecting device including the filter container 6 having the filter element 4 built therein. In the filter container 6, when the generated gas 16 passes through the filter element 4, the ash 10 contained in the generated gas 16 is collected on the outer surface of the filter element 4, and discharged to the downstream side as a clean gas. The collected ash 10 is timely removed by a pulse jet gas discharged from the blow nozzle 12 in a direction opposite to the gas flow (hereinafter, referred to as backwashing), and collected in a dust collection hopper (not shown) or the like.

[0004] Since the removed ash 10 contains a large amount of unburned carbon, gasification efficiency can be improved by charging the ash 10 again into the gasification furnace 13 after collecting dust. The gasification furnace 13 and the gas cooler 14 each have a built-in heat transfer tube 18, and heat transfer is performed by generating steam from the sensible heat of the high-temperature generated gas 16 or exchanging heat with a cold gas. And collect them.

A heat transfer tube that comes into contact with the high-temperature generated gas 16
Due to improper operating conditions, etc., the adhesion of the ash 10 on the surface of the heat transfer tube 18 increases, causing it to collide with the gas flow on the surface of the heat transfer tube 18 or deposit on the surface when falling. There is a problem that heat transfer is hindered, and the attached ash may progress and agglomerate or melt to form a hard clinker, which may cause a serious problem such as stopping the operation of the gasification facility. . Further, in the filter element 4, the properties of the ash 10 change due to improper operating conditions, and the ash 10 does not drop even when the filter element 4 is backwashed.
There is a problem that the filter element 4 is broken due to adhesion and growth of the ash 10 between the filter element 4 and the filter element 4 being fixed or being subjected to stress.

[0006]

In the prior art,
At the surface of the heat transfer tube that comes in contact with the high-temperature generated gas, the adhesion of the ash increases, and there is a problem that the gas collides with the surface of the heat transfer tube along with the gas flow, or adheres to the surface when it falls and deposits and hinders it. In addition, the attached ash may progress and agglomerate or melt to form a hard clinker, which may cause a serious problem such as stopping the operation of the gasification facility. Furthermore, in the filter element, the properties of the ash change, the ash does not drop even when the filter element is backwashed, and the filter element is fixed or the filter element is broken. Has occurred.

[0007] An object of the present invention is to review the operating conditions of a soot blow for a heat transfer tube and a filter element installed beforehand or to enhance the operation before the occurrence of a problem due to ash. An adhering ash prediction system that grasps the initial adhering ash situation or predicts the progress of ash adhering so as to prevent it before it occurs and to take advance measures such as changing the gasification equipment operating conditions to prevent problems. To provide.

[0008]

In order to achieve the above-mentioned object, a system for predicting attached ash according to the present invention comprises: a gasifier for gasifying a carbon-containing fuel to generate a product gas; Ash attached to a heat transfer tube or a filter element in a gas cooler and a dust collector that removes ash contained in the cooled product gas. A conductivity measuring device;
It consists of means for removing attached ash.
It is configured to record the change over time of the measured value, predict the progress of the attached ash based on the record, and control the removing means according to the prediction.

The removing means is a soot blow, and the conductivity measuring device is such that the electrode is installed near the surface of the heat transfer tube in the gas cooler together with the soot blow. The electrode of the measuring device is installed near the filter element in the dust collecting device, and the soot blow of the removing means and the electrode of the conductivity measuring device are installed in the dust collecting hopper of the dust collecting device. A plurality of pairs of electrodes of the configuration and conductivity measuring device are provided, and each pair of electrodes is disposed so as to be displaced from each other in a direction substantially perpendicular to or substantially parallel to the ash adhesion surface, and the measured value of each electrode is measured. Over time is
A configuration that is recorded is also possible.

[0010] The above-mentioned object is achieved by combining a conductivity measuring device and means for removing ash between measurement electrodes of the conductivity measuring device, and configuring an attached ash detection system. As means for removing ash deposited between the electrodes, soot blow using an inert gas such as a nitrogen gas and a compressed gas obtained by recycling a generated gas, or a mechanical removing means such as a vibrator or a knocker method may be used.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 5,
Gasification furnace 13 that gasifies carbon-containing fuel 17 such as coal to generate product gas, gas cooler 14 that cools and recovers heat of product gas 16, and removes ash 10 contained in the cooled product gas Provided in gasification equipment equipped with equipment consisting of a dust collector, as a conductivity measuring device 3 for ash 10 attached to the heat transfer tube 18 or filter element in the equipment, and as a means for removing the attached ash 10 The soot blow nozzle 12 is used to record the time-dependent change of measured values on the conductivity measuring device 3, for example, on the recording paper shown in FIG. 2, and compare this record with actual results to predict the progress of the attached ash 10. The operation of the removing means such as the soot blow nozzle 12 is controlled under conditions set in advance according to the prediction.

[0012] The removing means is a soot blow nozzle.
A configuration that is a soot blow that releases gas from 12, the conductivity measuring device 3 is a configuration in which the electrode is installed near the surface of the heat transfer tube 18 in the gas cooler 14 together with the soot blow, and a soot blow nozzle 12 of removal means, Conductivity measuring device
The electrode 1 of 3 is configured to be installed near the filter element 4 in the dust collector, and the soot blow nozzle 12 of the removing means, and the electrode 1 of the conductivity measuring device 3 is a diagram of the dust collector.
4, a plurality of pairs of electrodes 1 of the conductivity measuring device 3 are provided, and each pair of the electrodes 1 is attached to a surface to which the ash 10 is attached (the heat transfer tube 18 or the filter element 4). ) Are arranged so as to be displaced from each other in a substantially orthogonal direction or a substantially parallel direction, and the change with time of the measured value of each electrode 1 may be recorded on a recording paper as shown in FIG.

FIG. 1 shows the prior art gas cooler 14 shown in FIG.
FIG. 2 is an enlarged view of the vicinity of a heat transfer tube 18 installed in the inside. In this system, one pair of electrodes 1 of the conductivity measuring device 3 is installed near the surface of the heat transfer tube 18, and both electrodes 1 are connected to the conductivity measuring device 3 by a conductor 2.
Connect by. In addition, in the vicinity of the electrode 1 of the conductivity measuring device 3, a soot blow nozzle 12 for blowing a pressurized gas such as a recycle gas obtained by compressing nitrogen or a generated gas is installed,
The ash adhering to the surface of the heat transfer tube 18 is intermittently removed.

The effect of the present embodiment will be described with reference to FIG. This figure illustrates a change with time of the conductivity between the electrodes of the conductivity measuring device near the heat transfer tube of the gas cooler during the operation of the gasifier. The upper (I) shows the case where the amount of coal supplied to the gasifier gradually decreased and the supplied oxygen gradually exceeded the appropriate value, so that the attached ash advanced and the clinker grew on the heat transfer tube surface. The middle (II) shows the case where the amount of gasified oxygen is appropriate, the operation is performed stably, and no ash adheres to the surface of the heat transfer tube. It is.

To explain this figure in detail, first, the conductivity gradually increases with the attachment of ash, but the attached ash is removed by operating a soot blow at point a.
There is a tendency that the conductivity once decreases and then increases again with the adhesion of ash. However, when the gasification conditions are not appropriate (I), the change in conductivity gradually decreases, and eventually The adhesion of the ash has progressed strongly, and a portion that has not changed since the point c has appeared, and the adhesion of the ash that cannot be removed by soot blowing has been detected. That is, according to the present invention, in the vicinity of the surface of the heat transfer tube, by measuring the time change of the electrical conductivity between the electrodes in combination with soot blowing, the progress of the attached ash that cannot be removed is measured within the period of b in FIG. It becomes possible to predict by the decreasing tendency of the value, and therefore, before the point c where the trouble occurs, the operating pressure of the soot blow for the heat transfer tube and the filter element installed in advance is increased or the number of times of operation is enhanced. In addition, by reviewing the operating conditions of the gasification facility, such as correcting the oxygen amount to an appropriate value, it is possible to take advance measures to prevent problems such as heat transfer inhibition due to the growth of attached ash. For example, a plurality of operating conditions of the removing means such as soot blow may be stored in the control device, and the removing means may be controlled by inputting the selected operating conditions.

[0016] Further, a plurality of pairs of electrodes of the conductivity measuring device are installed at another location near the surface of the heat transfer tube and connected to the conductivity measuring device by a conducting wire, so that the ash adheres in the same manner as described above. The progress can be detected, and the range of the deposited ash and the prediction accuracy can be improved.

Alternatively, a plurality of pairs of electrodes of the conductivity measuring device are arranged so as to be shifted from each other in a direction perpendicular to the surface of the heat transfer tube, and are connected to the conductivity measuring device by a conductor.
In a pair near the tube surface, after the same conductivity change as described above appeared and the conductivity change disappeared, 2 provided above it
Since a similar change appears with a time delay after the pair, it is possible to detect the degree of clogging of the ash between the heat transfer tubes accompanying the progress of the ash adhesion. In the present embodiment, an example has been shown in which soot blow for an existing heat transfer tube is diverted as a means for removing ash attached to a measurement electrode tube. However, originally, soot blow dedicated to between electrodes and other mechanical removal are used. Even if means and the like are provided, the effects obtained by the present embodiment are the same.

FIG. 3 shows another embodiment of the present invention, which is an adhering ash prediction system for a filter system. FIG. 3 shows a filter element of the filter container 6 in FIG. 5 of the prior art.
4 is an enlarged view of the vicinity of FIG. In the dust collector using the filter element 4, when the generated gas passes through the surface layer of the filter element 4, dust adheres to the surface and is separated, but as the thickness increases, the differential pressure increases, and the operation control increases. Because of the above problems, backwashing usually involves installing a blow nozzle directly above the filter element 4,
Blow gas is ejected intermittently to blow off dust adhering to the surface to prevent clogging. According to this other embodiment, near the filter element 4 together with the blow nozzle, a pair of electrodes 1 of the conductivity measuring device is installed,
The two electrodes 1 are connected to the conductivity measuring device 3 by a conducting wire 2.

Here, the operation of the embodiment of the present invention will be described. The carbon contained in the ash is known as a good conductor that conducts electricity, and the reciprocal of the electrical resistance of the attached ash, that is, when the conductivity is measured by a conductivity measuring device using one or more electrodes, the carbon concentration in the ash is approximately It has been found that the conductivity increases in proportion to. By measuring the conductivity between the heat transfer tube surface and the filter element by this conductivity measuring device, the conductivity increases when ash starts to adhere. It has been observed that when the ash attached between the electrodes is removed by an intermittent blow gas or the like during the measurement of the conductivity, the conductivity decreases. However, when the carbon concentration in the ash decreases, the carbon begins to adhere between the heat transfer tubes and the filter elements.
As described above, when the attached ash is not easily removed due to the decrease in the carbon concentration, the value of the electrical conductivity gradually decreases, and the change with time decreases, so that it can be understood that the attachment is beginning to progress. Further, by setting two or more pairs of electrodes so as to be shifted from each other in the vertical direction or the horizontal direction with respect to the adhesion surface, it is possible to detect the degree of blockage and the adhesion range to the adhesion surface. In addition, by installing this system in a storage container such as a dust collection hopper, the carbon concentration in the attached ash can be measured, and the progress of the attached ash caused by the decrease in the carbon concentration can be predicted.

According to the present invention, a change in conductivity similar to the conductivity between the electrodes shown in FIG. 3 appears. In other words, the conductivity gradually increases with the progress of ash adhesion on the surface of the filter element, but the conductivity is temporarily reduced by backwashing with a blow gas at point a shown in FIG. Then, the tendency to increase again is shown, and if the gasification or the filter operating conditions are not appropriate, the change in the conductivity gradually decreases during the period of b, and the ash adhesion progresses, and the backwashing causes By detecting the attachment of the ash that cannot be removed, a flat portion with no change appears after the point c. That is, it is detected that the ash has adhered thickly between the filter elements. As described above, during the period b, it is possible to predict the risk of ash clogging between the elements and the risk of breakage from the change in conductivity. In this embodiment, an example in which the existing backwash blow system is used as the means for removing the attached ash between the electrodes has been described, but originally, a removing means such as a soot blow dedicated to the electrodes or other mechanical means is provided. The effect of the present invention is the same because the tendency of the change in the conductivity also indicates the tendency of ash to adhere.

FIG. 5 shows another embodiment of the present invention. Figure 5
Fig. 2 shows a dust collecting hopper in an ash dust collecting device such as a filter system. It is characterized in that the electrode 1 of the conductivity measuring device 3 and the soot blow 11 for removing ash attached to the electrode 1 are installed in the dust collection hopper 9.

According to the present invention, the conductivity of the collected ash is measured in the dust collecting hopper, and the measured value is almost proportional to the carbon concentration in the ash. , Which are extracted by batch operation and recycled to a gasifier. Thus, the conductivity of the ash, ie, the change in carbon concentration, can be measured. By observing the change with time, for example, when the carbon concentration becomes 5 wt% or less, it is possible to predict that the risk of ash adhesion growing has increased and to issue an alarm.

[0023]

According to the present invention, since the conductivity measuring device and the removing means are provided in the vicinity of the surface, a change with time in the conductivity of the attached ash can be detected, and the progress of the attached ash can be predicted.
By selecting the method and timing of the removing means, it is possible to prevent the risk of clogging and breakage of the attached ash between the heat transfer tubes and between the filter elements, etc., and to ensure the safe operation of the equipment.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating the effect of FIG. 1;

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing another embodiment of the present invention.

FIG. 5 is a diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode 2 Conductor 3 Conductivity measuring device 4 Filter element 5 Filter tube plate 6 Filter container 7 Gas inlet nozzle 8 Gas outlet nozzle 9 Dust collection hopper 10 Ash 11 Soot blow nozzle 12 Soot blow nozzle 13 Gasification furnace 14 Gas cooler 15 Cyclone 16 Product gas 17 Carbon-containing raw material 18 Heat transfer tube 19 Purified gas

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3K061 QB01 QB15 QB16 QC40 4D058 JA04 KA29 KB02 MA15 MA52 MA53 MA54 PA01 PA12 PA16 PA20 SA20 UA05 UA13 UA16 4H060 AA03 BB04 BB25 CC01 DD24

Claims (6)

[Claims] 1. A gasifier for gasifying a carbon-containing fuel to generate a product gas, a gas cooler for cooling and recovering heat of the product gas, and a dust collector for removing ash contained in the cooled product gas. The apparatus is provided in a gasification facility provided with equipment comprising equipment, and comprises a conductivity measuring device for ash attached to a heat transfer tube or a filter element in the equipment, and means for removing the attached ash, wherein the conductive material comprises: An adhering ash prediction system, which records a change with time of a measured value in a rate measuring device, predicts the progress of the adhering ash based on the recording, and controls the removing means according to the prediction. 2. The attached ash prediction system according to claim 1, wherein the removing means is a soot blow. 3. The attached ash prediction system according to claim 1, wherein the conductivity measuring device is installed near the surface of the heat transfer tube in the gas cooler together with the soot blow electrode. Forecasting system. 4. The adhesion ash prediction system according to claim 1, wherein the soot blow of the removing means and the electrode of the conductivity measuring device are installed near a filter element in the dust collecting device. Characteristic adhesion ash prediction system. 5. The attached ash prediction system according to claim 1, wherein the soot blow of the removing unit and the electrode of the conductivity measuring device are installed in a dust collecting hopper of the dust collecting device. Adhesion ash prediction system. 6. The adhesion ash prediction system according to claim 1, wherein a plurality of pairs of electrodes of the conductivity measuring device are provided, and each pair of electrodes is substantially formed on an adhesion surface of the ash. An adhering ash prediction system, which is installed so as to be shifted from each other in an orthogonal direction or a substantially parallel direction, and a change with time of a measured value of each electrode is recorded.