JP5761932B2 - Filter device regeneration method and filter device regeneration system - Google Patents

Description

  The present invention relates to a filter device regeneration method and a filter device regeneration system, and more particularly, to a filter device regeneration technique for collecting particulates from generated gas generated in a coal gasification furnace.

  In a coal gasification facility, it is known that a filter device is provided in a flow path of a product gas generated in a coal gasification furnace to collect particles contained in the product gas. The filter device is composed of a container provided with an opening that communicates with the upstream and downstream flow paths of the product gas, and a metal filter element that collects powder particles across the opening of the container. Is done.

  When the particulate matter is collected in the filter element, the ventilation resistance of the generated gas increases, so that the filter differential pressure ΔP on the upstream side and downstream side of the filter element measured by the differential pressure gauge installed in the filter device increases. To do. If the filter differential pressure ΔP continues to be collected, the pressure of not only the filter device but also the upstream device increases, and there is a possibility that the operation of the entire facility cannot be continued. Therefore, at a preset time interval or when the filter differential pressure ΔP reaches a preset set value, the backwash gas supply valve for supplying the backwash gas from the downstream side to the upstream side of the filter element is opened momentarily, In general, the granular material collected in the filter element is washed off by the flushing gas. The filter differential pressure ΔP recovered after the powder particles are removed by this backwash operation is referred to as a recovery differential pressure.

  However, a part of the granular material collected by the filter element enters into the place where it enters a little from the surface of the filter element to form a permanent layer. The particles in the permanent layer are not easily washed away by backwashing. As the powder particles are collected and backwashed repeatedly by the filter element, the particles in the permanent layer accumulate and are washed back. However, the recovery differential pressure of the filter may gradually increase.

  As described above, Patent Document 1 and Patent Document 1 disclose one of the means for regenerating the filter element in which the filter differential pressure ΔP does not recover even after backwashing, and the recovery differential pressure is increased by the granular material deposited on the permanent layer. Two techniques are known. In the technique of Patent Document 1, a gas adjusted to an oxygen concentration of 5 to 15 Vol.% Under normal pressure is supplied to a filter device, and the filter element is heated to 400 to 450 ° C. in the gas, thereby providing a permanent layer. The unburned carbon (carbon) contained in the granular material is oxidized (burned) and removed.

  On the other hand, the technique of Patent Document 2 takes out part of the combustion exhaust gas under normal pressure, adjusts the oxygen concentration to 5 to 20 Vol.%, And heats it to 80 to 400 ° C. to supply it to the filter device. According to this, it is said that unburned carbon (carbon) in the granular material adhering to the filter element can be removed by a so-called “external combustion” process having a slow oxidation reaction rate.

JP 2006-192337 A JP-A-8-309151

  By the way, the container in which the filter element is accommodated is usually manufactured as a pressure vessel, and the material of the pressure vessel is Cr-Mo steel, which is heat-resistant steel. In general, when the heat resistant steel is 400 ° C. or higher, the strength is lowered and the life of the container is shortened.

  Therefore, in the technique described in Patent Document 1, since the internal temperature of the container is set to 400 to 450 ° C., there is a concern that the life of the container may be shortened every time the filter device is regenerated. In particular, the heat effect on the tube plate to which the filter element is attached is large, and there is a risk that distortion after the regeneration processing of the filter element will increase.

  On the other hand, the technique described in Patent Document 2 is a method for removing carbon that is unburned in the granular material under conditions of a heat treatment temperature of 80 to 400 ° C. and an oxygen concentration of 5 to 20 vol. Therefore, the oxidation reaction rate of carbon is particularly slow under conditions of low temperature and low oxygen concentration, and it takes a very long time (days) to completely remove the carbon and regenerate the filter device. .

  Therefore, an object of the present invention is to regenerate the filter device by removing carbon adhering to the filter element in a shorter time while suppressing the thermal effect on the container of the filter device.

The filter device regeneration method of the present invention is basically provided in a flow path of a product gas generated in a coal gasification furnace that partially combusts coal to gasify it. A filter device having a container provided with an opening communicating with each of the passages and a filter element that collects powder particles in the generated gas across the two openings of the container. The filter device is regenerated by introducing a regeneration gas for burning carbon contained in the granular material.

  In particular, in a state where the internal pressure of the container is set to a preset pressure higher than atmospheric pressure, the temperature of the regeneration gas is controlled in the container so that the internal temperature of the container becomes a preset temperature of less than 400 ° C. It is characterized by being thrown in.

According to this, since the temperature of the regeneration gas is controlled so that the internal temperature of the container becomes a preset temperature of less than 400 ° C., it is possible to suppress the thermal influence (life reduction) on the container. it can. In addition to this, since the internal pressure of the container is set to a preset pressure higher than atmospheric pressure, carbon adhering to the filter element can be removed in a shorter time. That is, the carbon adhering to the filter element undergoes an oxidation reaction with oxygen in the regeneration gas, becomes a gas of carbon monoxide (CO) or carbon dioxide (CO ₂ ), and is removed from the permanent layer. At this time, if there is a large amount of oxygen around the carbon, an oxidation reaction between the carbon and oxygen tends to occur. In this respect, by increasing the atmospheric pressure inside the container and increasing the oxygen partial pressure as in the present invention, the number of oxygen molecules in the container, in other words, the number of oxygen molecules around the carbon can be increased. As a result, the oxidation (combustion) reaction of carbon can be promoted, so that the carbon adhering to the filter element can be removed in a shorter time.

  In the present invention, in addition to the above conditions, the oxygen concentration of the regeneration gas introduced into the container can be controlled to a preset concentration of 30 Vol. In addition, at least one of the oxygen concentration and the temperature of the regeneration gas charged into the container can be increased stepwise. Furthermore, one of the oxygen concentration and the temperature of the regeneration gas charged into the container can be increased stepwise and the other can be decreased stepwise.

  In other words, the oxidation reaction of carbon is an exothermic reaction, and the granular material contains oxides such as tar in addition to carbon. There is a risk of extending the service life. In this regard, by setting at least one of the oxygen concentration and the temperature of the regeneration gas to be low at the initial stage of the regeneration process, it is possible to suppress the oxidation reaction at the early stage of regeneration and suppress rapid heat generation. In addition to this, since carbon adhering to the filter element decreases as the regeneration process proceeds, a sudden exothermic reaction is caused by gradually increasing at least one of the oxygen concentration and temperature of the regeneration gas accordingly. Carbon can be removed in a shorter time while suppressing.

  Further, after the regeneration gas is introduced into the container and the regeneration of the filter device is started, the temperature of the regeneration gas on the inlet side of the container and the temperature of the regeneration gas on the outlet side of the container are detected, and the detected inlet When the difference between the side temperature and the outlet side temperature becomes smaller than a preset threshold value, the regeneration of the filter device can be finished.

  The filter device regeneration system according to the present invention includes a coal gasification furnace that partially gasifies coal to gasify, a generated gas flow path through which a generated gas generated in the coal gasification furnace flows, and this generation And a filter device that is provided in the gas flow path and collects the particulates in the generated gas flowing through the flow path. The filter device includes a container provided with an opening that communicates with the upstream and downstream flow paths of the product gas, and a filter element that collects the particulates across the two openings of the container. Is done. The regeneration system for the filter device also includes a regeneration gas input flow path for supplying a regeneration gas for burning the carbon in the granular material collected by the filter element to regenerate the filter device, and the container. A regeneration gas discharge passage for discharging the regeneration gas that has passed through the filter element, an inlet side temperature detector provided upstream of the filter element with respect to the flow of the regeneration gas inside the container, and a regeneration A temperature regulator provided in the gas input channel for heating or reducing the regeneration gas flowing through the channel, a pressure detector for detecting the internal pressure of the filter device, and a regeneration gas discharge channel. The regeneration gas outlet valve and a regeneration controller for performing regeneration control of the filter device are provided.

  Then, the regeneration controller controls the heating amount or heat reduction amount in the temperature regulator so that the internal temperature of the filter device detected by the inlet side temperature detector becomes a preset temperature less than 400 ° C., and pressure detection The opening degree of the regeneration gas outlet valve is controlled so that the internal pressure of the filter device detected by the vessel becomes a preset pressure higher than the atmospheric pressure.

  Further, instead of controlling the temperature controller in accordance with the temperature detected by the inlet side temperature detector, the flow of the regeneration gas inside the container is downstream of the filter element or the outlet side of the regeneration gas. An outlet side temperature detector is installed in the path, and the amount of heating or heat reduction in the temperature regulator is controlled so that the internal temperature of the filter device detected by the outlet side temperature detector becomes a preset temperature of less than 400 ° C. It can also be configured.

  That is, since the oxidation reaction of carbon is an exothermic reaction, there is a possibility that the outlet side may be 400 ° C. or higher even if the temperature on the inlet side of the regeneration gas is less than 400 ° C. Therefore, it is preferable to detect the temperature on the outlet side and control the temperature regulator so that the detected temperature is less than 400 ° C. When controlling the temperature regulator according to the temperature detected by the inlet side temperature detector, the preset temperature lower than 400 ° C. is set in consideration of the increase in the outlet side temperature of the regeneration gas due to the oxidation reaction of carbon. Is done.

  According to the present invention, it is possible to regenerate the filter device by removing carbon adhering to the filter element in a shorter time while suppressing the thermal effect on the container of the filter device.

It is a figure which shows the whole structure of the coal gasification equipment containing the filter reproduction | regeneration system of this embodiment. It is a figure explaining an example of the structure of a filter apparatus. It is a figure which shows the example of a behavior of filter differential pressure (DELTA) P at the time of dust collection and backwashing of a timer type backwash control system filter apparatus. It is a figure which shows the principle of dust collection and backwashing by a filter element. It is a figure which shows the structure of the reproduction | regeneration system of the filter apparatus of this embodiment. It is a figure which shows the heating regeneration conditions with respect to the atmospheric pressure change of a filter element. It is a figure which shows the heating regeneration conditions with respect to the oxygen concentration change of a filter element. It is the figure which represented the result by an example of the regeneration method of the filter apparatus of this embodiment in time series. It is a figure which shows the mode of the filter element before and behind a heat reproduction process. It is the figure which represented the result by an example of the regeneration method of the filter apparatus of this embodiment in time series. It is the figure which represented the result by an example of the regeneration method of the filter apparatus of this embodiment in time series.

  Hereinafter, embodiments of a filter device regeneration system and a filter device regeneration method to which the present invention is applied will be described. In the following description, the same functional parts are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is a diagram showing an overall configuration of a coal gasification facility including a filter device regeneration system of the present embodiment. As shown in FIG. 1, the coal gasification facility 100 is provided in a flow path of a coal gasification furnace 10 that partially gasifies and gasifies coal and a product gas 28 generated in the coal gasification furnace 10. The heat recovery boiler 12 that recovers the heat of the gas 28, the cyclone 14 that collects the particulate matter in the generated gas 28, and the filter device 16 are configured. In addition to unburned carbon (C), ash is present in the granular material. Ash is composed of oxides such as silicon (Si), aluminum (Al) and calcium (Ca), silica oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), calcium oxide (CaO) and the like.

  The coal gasification facility 100 also has a hopper 18 that collects the granular material collected by the cyclone 14 and the filter device 16, and a transport pipe that circulates the granular material collected by the hopper 18 to the coal gasification furnace 10. 20 and a rotary valve 22 provided in the transport pipe 20.

The coal gasification furnace 10 is provided with a gasification burner 24 and a char burner 26. Mainly carbon monoxide (CO) and hydrogen (H ₂ ) are used for pulverized fuel such as char containing pulverized coal and carbon at a high temperature. It gasifies into the product gas 28 used as a component. On the other hand, a cooling water pool 30 is provided at the bottom of the coal gasification furnace 10, and the granulated slag 32 generated by the cooling water pool 30 is discharged from the bottom of the coal gasification furnace 10.

  The product gas 28 sent to the heat recovery boiler 12 is recovered by heat in a medium 34 such as water supplied to the heat recovery boiler 12 and then sent to the cyclone 14 through the flow path of the product gas 28. On the other hand, the medium 34 such as water recovered by the heat recovery boiler 12 is discharged from the heat recovery boiler 12 as steam 35. The produced gas 28 sent to the cyclone 14 is collected by the cyclone 14 in the form of particles contained in the produced gas 28, and further sent to the filter device 16 through the flow path of the produced gas. In the produced gas 28 sent to the filter device 16, fine powder particles that could not be collected by the cyclone 14 are collected by the filter device 16. The produced gas 28 in which the powder particles are collected is discharged from the filter device 16 as a dedusting gas 36. On the other hand, the granular material collected by the cyclone 14 and the filter device 16 is collected by the hopper 18, then cut out by the rotary valve 22, and again fed into the coal gasification furnace 10 through the transport pipe 20.

  Here, an example of the structure of the filter device 16 will be described with reference to FIG. As shown in FIG. 2, the filter device 16 includes a container 40 provided with openings that communicate with the upstream and downstream flow paths of the product gas, and powder contained in the product gas across both openings of the container 40. And a metal filter element 42 for collecting particles. In addition, a backwash gas supply valve 46 is provided for removing powder particles adhering to the filter element 42 with the backwash gas 44. During operation of the gasification facility 100, the product gas 28 obtained by gasifying coal is input from the lower part of the filter device 16. The filter element 42 collects the particulate matter in the product gas 28 and removes the solid content in the product gas 28 to obtain a clean dust removal gas 36.

  Here, on the upstream side of the filter element 42 with respect to the flow of the product gas 28 in the container 40, an inlet-side pressure gauge 48 for measuring the pressure inside the container 40 is provided, and upstream of the product gas inside the container 40. An inlet-side thermometer 50 and an outlet-side thermometer 51 for measuring the temperature on the side and the downstream side are provided. When the particulate matter is collected, the filter differential pressure ΔP measured by the differential pressure gauge 52 installed in the filter device 16 increases when the ventilation resistance of the filter element 42 increases. When the filter differential pressure ΔP reaches a predetermined set value or every set time interval, the backwash gas supply valve 46 opens momentarily, and the powder and particles collected in the filter element 42 by the backwash gas 44 are removed. It will be paid off. By this operation, the filter element 42 is cleaned, and the filter differential pressure ΔP is restored to the differential pressure before collecting the particulates.

  Subsequently, a change in differential pressure during collection and backwashing of the powder particles by the filter device 16 and a principle of collecting the powder particles by the filter element 42 will be described in detail. FIG. 3 is a diagram illustrating the behavior of the filter differential pressure ΔP during the dust collection / backwashing of the filter device 16, and FIG. 4 is a diagram illustrating the principle of dust collection and backwashing by the filter element 42.

  When the granular material 54 is collected from the generated gas 28, the filtration area of the filter element 42 is reduced and the airflow resistance is gradually increased, so that the filter differential pressure ΔP gradually increases. At this time, the granular material 54 is collected on the surface of the filter element 42 as shown in FIG. Here, the granular material 54 enters a place slightly entering from the surface of the filter element 42 to form a permanent layer 56. As the powder particles 54 are further collected, the differential pressure ΔP of the filter element 42 increases. If the differential pressure ΔP continues to rise, stable operation of the coal gasification facility 100 becomes difficult. Therefore, a backwash operation is performed at the preset timer time or when the preset filter differential pressure ΔP is reached. FIG. 3 shows an example of the behavior of the filter differential pressure ΔP in the timer type backwashing method in which the backwashing operation is repeated at set time intervals.

  As shown in FIG. 4 (b), the granular material 54 collected by this operation is removed from the filter element 42, but the permanent layer 56 remains in the filter element 42. Immediately after the start of use of the filter element 42, the filter differential pressure ΔP substantially recovers to the differential pressure immediately after the collection of the powder particles 54. However, as the collection and backwashing of the powder 54 are repeated, the powder 54 that cannot be removed by the backwash operation remains in the permanent layer 56, and the differential pressure ΔP of the filter element 42 does not recover.

  On the other hand, for example, a gas adjusted to an oxygen concentration of 5 to 15 Vol.% Under normal pressure is supplied to the filter device, and the filter element is heated in the gas at 400 to 450 ° C. It is known to oxidize and remove carbon. Further, a filter element is extracted by a so-called “external combustion” process in which a part of the combustion exhaust gas is taken out under normal pressure and the oxygen concentration is adjusted to 5 to 20 vol. A method for removing unburned carbon adhering to the surface is also known.

  However, the container 40 in which the filter element 42 is accommodated is usually manufactured as a pressure container, and the material of the pressure container is Cr-Mo steel, which is heat-resistant steel. In general, when the heat resistant steel is 400 ° C. or higher, the strength is lowered and the life of the container 40 is shortened. Therefore, if the filter element 42 is heat-treated at 400 to 450 ° C., the life of the container 40 may be shortened every time the filter device is regenerated. In particular, the heat effect on the tube plate to which the filter element 42 is attached is large, and there is a risk that the distortion of the filter element 42 after the regeneration process will increase. In this regard, it is conceivable to remove the filter element 42 from the container 40 at the time of regeneration, but in this case, it is necessary to manage the corrosion of the filter element 42 due to moisture absorption in the atmosphere and the thermal strain deformation of the tube plate attached to the filter element 42. Since it is not preferable, regeneration in a container is desired.

  On the other hand, in the case of long combustion, there is little risk of the life of the vessel being short, but the oxidation reaction rate of carbon is particularly slow under conditions of low temperature and low oxygen concentration, and the filter device is regenerated by completely removing the carbon by burning. It takes a lot of time (days) to be unfavorable.

  The regeneration system for the filter device of the present embodiment has been made in view of this point, and removes carbon adhering to the filter element 42 in a shorter time while suppressing the thermal influence on the container 40 of the filter device 16. Thus, the filter device 16 is regenerated. Hereinafter, details of the regeneration system of the filter device 16 will be described.

  FIG. 5 is a diagram showing the configuration of the regeneration system for the filter device of the present embodiment. The description of the same configuration as that described in FIG. 4 is omitted. As shown in FIG. 5, the regeneration system of the filter device 16 is a regeneration in which a regeneration gas 58 that regenerates the filter device 16 by burning carbon in the granular material collected by the filter element 42 is put into the container 40. A regenerative gas discharge passage 62 for discharging the regenerative gas 58 introduced into the container 40 and passed through the filter element 42 is provided.

  The regeneration gas input channel 60 is connected to a product gas channel 64 that inputs the product gas 28 into the container 40, and the regeneration gas 58 is part of the regeneration gas input channel 60 and the product gas channel 64. To be supplied to the container 40. A product gas inlet valve 66 is provided upstream of the connection portion of the regeneration gas input channel 60 in the product gas channel 64. On the other hand, the regeneration gas discharge flow path 62 is branched from a generated gas flow path 68 through which the generated gas (dust removal gas 36) discharged from the container 40 flows. A product gas outlet valve 70 is provided downstream of the branch portion of the regeneration gas discharge channel 62 in the product gas channel 68. When the char filter element regeneration process is performed after the operation of the coal gasification facility 100 is stopped, the product gas inlet valve 66 and the product gas outlet valve 70 are closed so that the regeneration gas 58 does not flow to others. . Moreover, the granular material piping which discharges the collected granular material is provided in the bottom part of the container 40, and the granular material outlet valve 71 is provided in the granular material piping.

  In addition, the regeneration system for the filter device is provided in the regeneration gas input channel 60, and a temperature regulator 73 that heats or reduces the regeneration gas 58 that flows through the channel, and the regeneration gas input channel 60. An oxygen concentration analyzer 72 provided in the gas generator, and an adjustment gas input channel 78 for supplying oxygen 74 and nitrogen 76 as adjustment gases upstream of the oxygen concentration analyzer 72 of the regeneration gas input channel 60; A regeneration gas inlet valve 80 provided in the regeneration gas input passage 60, a regeneration gas outlet valve 82 provided in the regeneration gas discharge passage 62, and a regeneration controller 84 that performs regeneration control of the filter device 16. And. The regeneration gas input flow path 60 on the downstream side of the container 40 and the temperature regulator 73 of the filter device 16 is covered with a heat insulating material 75, so that the temperature of the regeneration gas 58 is hardly lost.

  In this embodiment, since the flow direction of the product gas 28 and the flow direction of the regeneration gas 58 are the same direction, the above-described inlet-side thermometer 50 corresponds to the flow of the regeneration gas 58 inside the container 40. It is provided upstream of the filter element 42 and serves as a container inlet gas temperature detector for the regeneration gas 58. The inlet side pressure gauge 48 serves as a pressure detector that detects the internal pressure of the filter device 16.

  The regeneration controller 84 is supplied with the temperature detected by the inlet-side thermometer 50, the pressure detected by the inlet-side pressure gauge 48, and the oxygen concentration detected by the oxygen concentration analyzer 72. . The regeneration controller 84 controls the heating amount or heat reduction amount in the temperature regulator 73, the valve opening degree of the regeneration gas outlet valve 82, and the flow rate of the regulating gas based on the three input detection values. is there.

By the way, in order to regenerate the filter element 42, it is necessary to remove the particulates collected in the permanent layer 56 on the surface of the filter element 42. In addition to carbon (C), ash is present in the granular material. Ash is composed of oxides such as silicon (Si), aluminum (Al) and calcium (Ca), silica oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), calcium oxide (CaO) and the like. These melting points are SiO ₂
About 1700 ° C., Al ₂ O ₃ about 2050 ° C., and CAO about 2570 ° C. are very high and thermodynamically very stable. Therefore, it cannot be easily removed at temperatures below 400 ° C. Therefore, the filter element is regenerated by paying attention to removing the carbon collected in the permanent layer 56. The following equations (1) and (2) show the reaction formula of carbon and oxygen.

_{C + 1 / 2O 2 → CO} -111MJ / kmol ··· (1)
C + O ₂ → CO ₂ −394 MJ / kmol (2)

The carbon undergoes an oxidation reaction with oxygen in the gas, becomes carbon monoxide (CO) or carbon dioxide (CO ₂ ) gas, and is removed from the permanent layer 56. At this time, if there is a large amount of oxygen around the carbon, the probability that the carbon meets the oxygen increases and an oxidation reaction is likely to occur. For this purpose, there is a method in which the atmospheric pressure is increased to increase the oxygen partial pressure. That is, the number of oxygen molecules in the container 40 is increased to increase the number of oxygen molecules around the carbon. Therefore, by increasing the atmospheric pressure, the oxidation reaction between carbon and oxygen can be promoted, and the heating temperature during regeneration can be lowered.

  In view of this point, the regeneration controller 84 of the present embodiment uses the temperature regulator 73 so that the internal temperature of the filter device 16 detected by the inlet-side thermometer 50 becomes a preset temperature of less than 400 ° C. The amount of heating or heat reduction is controlled, and the opening degree of the regeneration gas outlet valve 82 is controlled so that the internal pressure of the filter device 116 detected by the inlet side pressure gauge 48 becomes higher than the atmospheric pressure and set in advance. To do. The lower limit of the internal temperature is, for example, 300 ° C., and the upper limit of the internal pressure is, for example, 3.0 MPa (Gage). In addition, the regeneration controller 84 controls the flow rate of the adjustment gas so that the oxygen concentration of the regeneration gas 58 detected by the oxygen concentration analyzer 72 becomes a preset concentration of 30 Vol. The lower limit of the oxygen concentration is, for example, 2 Vol.%. In addition, when the heating amount or the heat reduction amount in the temperature regulator 73 is controlled according to the temperature detected by the inlet side thermometer 50, the preset temperature lower than 400 ° C. is the temperature of the regeneration gas 58 by the carbon oxidation reaction. It is set in consideration of the rise in outlet side temperature.

  FIG. 6 is a diagram showing a heating regeneration condition with respect to a change in atmospheric pressure of the filter element 42, and FIG. 7 is a diagram showing a heating regeneration condition with respect to a change in oxygen concentration of the filter element 42. These figures are an example of the results obtained by the inventors of the test by determining the relationship between the carbon reaction rate and the atmospheric pressure, the heating temperature and the oxygen concentration, and calculating the element heating regeneration conditions from the carbon reaction rate.

  FIG. 6 shows the relationship between the heating temperature and the number of regeneration days when the atmospheric pressure of the filter element 42 is changed at an oxygen concentration of 21 Vol. In FIG. 6, curves a, b, c, d, e, f, and g indicate that the atmospheric pressure is 0 MPa (Gage), 0.5 MPa (Gage), 1.0 MPa (Gage), 1.5 MPa (Gage), The relationship between the heating temperature and the number of regeneration days at 2.0 MPa (Gage), 2.5 MPa (Gage), and 3.0 MPa (Gage) is shown. On the other hand, FIG. 7 shows the relationship between the heating temperature and the number of regeneration days when the oxygen concentration of the filter element 42 is changed at an atmospheric pressure of 2.5 MPa (Gage). In FIG. 7, curves h, i, j, k, and l indicate the relationship between the heating temperature and the number of regeneration days when the oxygen concentration is 2 Vol.%, 5 Vol.%, 10 Vol.%, 21 Vol.%, And 30 Vol.%, Respectively. Is shown.

For example, in FIG. 6, when the regeneration process is performed for 48 hours (2 days) at an oxygen concentration of 21 Vol.%, The heating temperature is about 410 ° C. under normal pressure, whereas the atmospheric pressure is 2.5 MPa (Gage). It can be seen that the heating temperature can be reduced by 343 ° C, that is, about 345 ° C and 65 ° C. In addition, if the heat treatment is performed under normal pressure conditions at this heating temperature of 345 ° C., a regeneration time of 648 h (27 days) is required. Therefore, it can be seen that, in the heat filter heat regeneration process, it is very effective when the atmosphere is set to a pressurized condition.

FIG. 7 shows the relationship between the heating temperature and the regeneration time (days) when the oxygen concentration is changed to 2 to 30 Vol.% At an atmospheric pressure of 2.5 MPa (Gage). In the case of 120 hours (5 days) of heat regeneration, the filter element can be regenerated by removing carbon at a heating temperature of 366 ° C., that is, about 370 ° C., even under a low oxygen concentration condition of 2 Vol.%. I understand that I can do it. Also in this figure, it can be seen that setting the atmosphere to a pressurized condition is effective for heat treatment regeneration, and that the char filter can be regenerated even at a low oxygen concentration. Here, when the oxygen concentration is increased, the heating temperature is lowered and the regeneration time (days) can be reduced. However, it is clear that the effect, that is, the width between the lines indicating the tendency of each concentration in the figure gradually decreases when the oxygen concentration is 2 Vol.%, 10 Vol.%, 21 Vol.%, And 30 Vol.%. It is. From this tendency, it is presumed that the effect of shortening the reproduction time (days) is not so great under the condition of 30 Vol. Therefore, in this embodiment, the upper limit of the oxygen concentration is set to 30 Vol.%. Moreover, the oxidation reaction of carbon in char is slow when the heating temperature is 400 ° C. or less, and as shown in FIGS. 6 and 7, the regeneration time (day) tends to increase rapidly. Required for processing. However, even if the oxygen concentration is 2 Vol.%, The filter element can be regenerated in a relatively short period of less than 14 days if the atmosphere is set to a pressure of 2.5 MPa (Gage) and the heating temperature is 340 ° C. or higher. Therefore, in this embodiment, the lower limit of the oxygen concentration is set to 2 Vol.%.

When carbon oxidizes, it turns out that it is an exothermic reaction as shown to said Formula (1) and (2). In addition to carbon, the particles contain oxides such as tar. If a sudden exothermic reaction occurs during the regeneration process of the filter element, it is not preferable in terms of reducing the life of the container 40. However, when the gasification facility is stopped, if the backwashing and purging of the filter device 16 are sufficient, it is considered that the amount of the granular material remaining on the filter element 42 is small. Assuming a regeneration time of oxygen pressure of 21 Vol.%, Atmospheric pressure of 2.5 MPa (Gage), and 240 h (10 days), the heating temperature is 308 ° C., that is, about 310 ° C. from FIG. Temperature cause rapid oxidation reaction of carbon generates heat, that is a result of inventors combustion start temperature of carbon was measured, since under the same conditions of about 430 ° C., rapid heat generation of the carbon with the proviso that this about 310 ° C. It is estimated that no reaction occurs.

  Next, the procedure of the regeneration method of the filter device 16 will be described. First, when the regeneration of the filter element 42 is started, the product gas inlet valve 66, the product gas outlet valve 70, and the granular material outlet valve 71 are closed. Next, the regeneration gas inlet valve 80 is opened and the regeneration gas 58 is introduced into the container 40, and the temperature of the input regeneration gas 58 is measured by the inlet side thermometer 50. Then, the regeneration gas 58 is heated by the temperature regulator 73 so that the measured value becomes a preset heating temperature at the time of element regeneration.

  The temperature regulator 73 can be constituted by a heat exchanger, for example. In this case, a high-temperature combustion gas obtained by burning fuel can be supplied as a heat source for the heat exchanger. Moreover, the temperature regulator 73 can also be comprised using an electric heater. Further, the high-temperature combustion gas may be used as the regeneration gas 58 as it is. In this case, the temperature regulator 73 can be omitted.

  Next, the oxygen concentration in the regeneration gas 58 is measured by the oxygen concentration analyzer 72. For example, when the oxygen concentration of air or the like is known as the regeneration gas 58, or when a mixed gas of nitrogen and oxygen prepared in advance is used as the regeneration gas 58, the oxygen concentration analyzer 72 is unnecessary. When a gas with unknown oxygen concentration, such as combustion gas, is used as the regeneration gas 58, the oxygen 74 and nitrogen are adjusted so that the oxygen concentration is set to a preset regeneration condition based on the value measured by the oxygen concentration analyzer 72. A flow rate of 76 is determined.

  Subsequently, the internal pressure of the filter device 16 is measured by the inlet side pressure gauge 48. The opening degree of the regeneration gas outlet valve 82 is adjusted so that this value becomes the pressure of the regeneration condition set in advance. In this way, conditions of temperature, pressure and oxygen concentration necessary for the regeneration of the filter element 42 are adjusted. Thereafter, this condition is maintained for a time required for element regeneration, and the filter element 42 is regenerated.

  FIG. 8 is a diagram showing a result of an example of the regeneration method of the filter device of the present embodiment in time series. In FIG. 8, the horizontal axis takes time, and from above the internal pressure of the filter device 16 (internal pressure of the container 40), the oxygen concentration in the regeneration gas, the internal temperature of the container, the amount of carbon adhering to the filter element, and the filter differential pressure ΔP. Show. FIG. 8 shows the change over time when the internal pressure of the filter device 16 is 2.5 MPa (Gage), the oxygen concentration is 21 Vol.%, The heating temperature is 310 ° C., and the regeneration time is 240 h (10 days). The time when the three conditions of the internal pressure of the filter device 16, the oxygen concentration, and the inlet gas temperature of the filter element become the regeneration conditions is the start of the filter element regeneration process.

As shown in FIG. 8, the internal pressure of the filter device 16, the oxygen concentration in the regeneration gas, and the filter element inlet gas temperature are constant until the point A where the regeneration process is completed. As shown in the formulas (1) and (2), carbon in the granular material is removed as a CO or CO ₂ gas by an oxidation reaction with oxygen in the regeneration gas. Therefore, the amount of carbon adhering to the filter element gradually decreases with the passage of time. When the carbon in the granular material is removed, the differential pressure ΔP of the filter element decreases, and the element regeneration process is completed at point A after the regeneration process time has elapsed.

  FIG. 9 is a diagram illustrating a state of the filter element before and after the heat regeneration process. FIG. 9 shows the state of the permanent layer 56 in the surface layer portion of the filter element 42, the granular material 54 entering the permanent layer 56, the ash content 90 in the granular material 54, and the carbon 92. FIG. 9A shows a state before regeneration, in which ash 90 and carbon 92 are present in the permanent layer 56. FIG. 9B shows a state after heat regeneration, in which the carbon 92 is removed by the heat regeneration process, and only the ash content 90 in the granular material 54 remains. When the carbon 92 is removed, the volume of the portion where the carbon 92 was present becomes a space, so that the flow path area increases, and the element differential pressure ΔP decreases as shown in FIG.

  The permanent layer 56 from which the carbon 92 in the granular material 54 has been removed by the heat regeneration treatment is in a fragile state due to an increase in voids, and easily passes through the backwash gas 44. Therefore, the ash 90 in the permanent layer 56 remaining after the heat regeneration process can be removed by backwashing operation. FIG. 9C shows how the ash 90 in the permanent layer 56 is removed. After the heat regeneration treatment, the filter element is more effectively removed by opening the backwash gas supply valve 46 for a moment and allowing the backwash gas 44 to pass through the filter element 42 to remove the ash 90, as in the normal backwash operation. 42 playbacks can be performed.

  Also, instead of backwashing after the element regeneration process, the regeneration gas is flowed in the backwash direction, that is, in the direction opposite to the gas flow direction described in this embodiment, to regenerate the element. Processing may be performed. However, in that case, if foreign matter is mixed in the regeneration gas, the foreign matter may adhere to the inside of the filter element 42. Therefore, it is necessary to take care such as attaching a filter so that foreign matter does not enter the regeneration gas.

  By the way, as in the carbon oxidation reaction formulas shown in the above formulas (1) and (2), the carbon oxidation reaction is an exothermic reaction. Therefore, as shown in FIG. 8, the filter outlet gas temperature is slightly higher than the inlet gas temperature. As the heat regeneration process proceeds and the amount of adhering carbon decreases, the filter outlet gas temperature gradually decreases. When the amount of carbon in the granular material disappears, the oxidation reaction is completed, so the amount of heat generation becomes 0, and the filter inlet gas temperature and the filter outlet gas temperature become the same gas temperature. Thus, when the inlet gas temperature and the outlet gas temperature are the same, it can be used as a guideline for determining that the heat regeneration process has ended.

  Note that the regeneration controller 84 is set in advance so that the detected temperature at the outlet side thermometer 51 is less than 400 ° C. instead of controlling the temperature regulator 73 according to the detected temperature at the inlet side thermometer 50. It is also possible to control the amount of heating or the amount of heat reduction in the temperature regulator 73 so that the temperature is reached.

  In other words, since the oxidation reaction of carbon is an exothermic reaction, the gas temperature on the outlet side may be 400 ° C. or higher even if the gas temperature on the inlet side of the filter container is less than 400 ° C. Therefore, it is preferable to detect the gas temperature on the outlet side and control the temperature regulator 73 so that the detected temperature is less than 400 ° C.

  FIG. 10 is a diagram showing the results of an example of the regeneration method of the filter device of this embodiment in time series. Similar to FIG. 8, time is taken on the horizontal axis, and from the top, the internal pressure of the filter device 16, the oxygen concentration in the regeneration gas 58, the container internal temperature, the amount of carbon attached to the filter element, and the filter differential pressure ΔP are shown. In this example, at least one of the flow rate of the adjustment gas and the temperature in the temperature regulator 73 is controlled so that at least one of the oxygen concentration of the regeneration gas 58 introduced into the container and the temperature inside the container increase stepwise. Is. More specifically, the heating temperature of the regeneration gas 58 is adjusted to increase the container internal temperature stepwise. Instead of adjusting the heating temperature of the regeneration gas 58 to increase the container internal temperature stepwise, the oxygen concentration may be increased stepwise, or both may be increased stepwise. .

  Here, a method for heat-treating the container internal temperature in two stages of Step 1 and Step 2 will be described. The container internal temperature in Step 1 was 310 ° C., and the container internal temperature in Step 2 was 345 ° C. The regeneration heat treatment time, which is the carbon oxidation reaction end time under these heating temperature conditions, is 240 h (10 days) and 48 h (2 days), respectively, from FIG. Here, since the heat treatment is performed in two stages, the heating time is set to half of the time for completing the oxidation reaction of carbon in both steps, that is, 120 h (5 days) and 24 h (1 day), respectively.

  The internal pressure of the filter device 16 and the oxygen concentration in the regeneration gas are 2.5 MPa (Gage) and 21 Vol.%, Respectively, and are constant until the element regeneration process is completed. When the three items of the internal pressure of the filter device 16, the oxygen concentration in the regeneration gas, and the char filter container inlet gas temperature are the regeneration conditions, the regeneration process of Step 1 is started. After the time 120h (5 days) when the carbon and oxygen in the regeneration gas progress and the amount of carbon attached to the filter element reaches 50%, the heating temperature is changed to 345 ° C., which is the heating condition of Step 2. .

  After changing the set value of the internal temperature of the container, the remaining attached carbon is removed by heat treatment for 24 hours (1 day). In the two-stage heat treatment according to this example, the heat treatment is completed in a total of 144 h (6 days). If the heat regeneration process is performed at a constant heat treatment temperature of 310 ° C., it takes 240 hours (10 days), whereas the element regeneration process is completed in 144 hours (six days). Therefore, it can be shortened for 4 days. When raising the heating temperature step by step, if the temperature is changed from the high temperature condition to the low temperature condition, a large amount of carbon present in the initial stage of the regeneration may react and generate heat. It is a safe way.

  FIG. 11 is a diagram showing the results of an example of the regeneration method of the filter device of this embodiment in time series. Similarly to FIG. 10, the horizontal axis indicates time, and the internal pressure of the filter device 16, the oxygen concentration in the regeneration gas, the container internal temperature, the amount of carbon attached to the filter element, and the filter differential pressure ΔP are shown in order from the top. In this example, at least one of the flow rate of the adjustment gas and the temperature in the temperature regulator 73 is controlled so that one of the oxygen concentration of the regeneration gas 58 introduced into the vessel 40 and the temperature inside the vessel increase stepwise. At the same time, the other one of the flow rate of the adjusting gas and the temperature in the temperature controller 73 is controlled so that the other of the oxygen concentration of the regeneration gas 58 introduced into the container 40 and the other of the container internal temperature decreases stepwise. is there. In the following, an example is described in which the oxygen concentration of the regeneration gas is increased stepwise and the container internal temperature is decreased stepwise. However, the present invention is not limited to this, and the container internal temperature is increased stepwise to increase the oxygen concentration stepwise. Can also be reduced.

  Here, as an example, a method for performing heat treatment by changing the container internal temperature and the oxygen concentration in two stages of Step 1 and Step 2 will be described. The container internal temperature and oxygen concentration in Step 1 were 370 ° C. × 2 Vol.%, And in Step 2, 310 ° C. × 21 Vol.%. The regeneration heat treatment times under these heating temperature conditions are 120 h (5 days) and 240 h (10 days), respectively, from FIG. Similarly to FIG. 10 described above, since the heat treatment is performed in two stages, 60 h (2.5 days) and 120 h (5 days), which are half of the carbon oxidation reaction completion time in both steps, were used as the heat treatment time.

  The internal pressure of the filter device 16 is 2.5 MPa (Gage) and is constant until the heat regeneration process is completed. When the three conditions of the internal pressure of the filter device, the oxygen concentration in the regeneration gas 58, and the char filter container inlet gas temperature are the regeneration conditions, the regeneration process of Step 1 is started. After the oxidation reaction between carbon and oxygen in the regeneration gas proceeds and the amount of carbon attached to the filter element reaches 50% for 60 hours (2.5 days), the oxygen concentration as the heating condition in Step 2 is set to 2 Vol.%. To 21 vol.%, And the internal temperature of the container is lowered from 370 ° C to 310 ° C. After changing the container internal temperature and oxygen concentration, the remaining attached carbon is removed by a heat treatment of 120 h (5 days).

  In this two-stage heat treatment, the heat treatment is completed in a total of 180 hours (7.5 days). When heat regeneration treatment is performed at a constant heat treatment temperature of 310 ° C., it takes 240 hours (10 days), while 60 hours (2.5 days) can be shortened. By the way, it is desirable to set the heating temperature high in order to reliably remove carbon in the char in the heat treatment. However, at the initial stage of the heat treatment, there is a concern about heat generation due to a rapid oxidation reaction of carbon. FIG. 7 shows heating regeneration conditions with respect to changes in oxygen concentration. At the pressure of 2.5 MPa (Gage) and the temperature of 370 ° C., which are the regeneration conditions of this embodiment, the carbon in the char is removed in about 1 day at an oxygen concentration of 21 Vol.% And in about 5 days at an oxygen concentration of 2 Vol.%. I understand that I can do it. Therefore, even if the heat treatment temperature is increased to 370 ° C., the oxygen concentration is 21 Vol. % To 2 Vol. %, The oxidation reaction rate can be reduced to 1/5, and heat generation due to a rapid oxidation reaction of carbon can be suppressed. FIG. 6 shows heating regeneration conditions with respect to pressure changes. In this embodiment, the heat treatment condition of step 2 is a temperature of 310 ° C. and an oxygen concentration of 21 Vol. %, If the pressure is 0 MPa (Gage), which is normal pressure, the number of regeneration days exceeds 30 days. Therefore, the oxygen concentration is 21 Vol. By increasing the ratio to 50%, it is possible to heat and regenerate the filter element in a short time even under a heating temperature condition as low as 310 ° C. As a result, the conditions of the heating temperature and oxygen concentration can be set in a wider range than normal pressure regeneration, and the regeneration process of the char filter element can be performed safely by setting the oxygen concentration low in the initial stage of the regeneration process.

  As described above, according to the regeneration system and regeneration method of the filter device of the present embodiment, the heat regeneration process is performed in a state where the pressure inside the container of the filter device is higher than the atmospheric pressure. Moreover, the oxidation reaction of carbon collected by the filter element can be promoted and removed in a shorter time. As a result, it is possible to regenerate the filter device by removing the carbon adhering to the filter element in a shorter time while suppressing the thermal effect on the container of the filter device.

  Further, in the coal gasification facility including the filter device, it is possible to extend the life of the filter device, to stabilize the operation of the coal gasification facility by preventing an increase in the differential pressure for each operation, and to improve the reliability. Further, when the filter differential pressure increases, the operation of the gasification facility is forced to stop. According to this embodiment, the time during the stop period of the coal gasification facility can be shortened, It becomes possible to operate economically.

DESCRIPTION OF SYMBOLS 10 Coal gasifier 16 Filter apparatus 28 Product gas 40 Container 42 Filter element 48 Inlet side pressure gauge 50 Inlet side thermometer 52 Differential pressure gauge 54 Granule 58 Regeneration gas 60 Regeneration gas input flow path 62 Regeneration gas discharge flow Paths 64, 68 Product gas flow channel 66 Product gas inlet valve 70 Product gas outlet valve 72 Oxygen concentration analyzer 73 Temperature controller 74 Oxygen 76 Nitrogen 78 Adjustment gas input flow channel 80 Regeneration gas inlet valve 82 Regeneration gas outlet valve 84 Regeneration controller 90 Ash 92 Carbon 100 Coal gasification facility

Claims (10)

A container provided in a flow path of a product gas generated in a coal gasification furnace for partially combusting and gasifying coal, and provided with openings respectively communicating with the upstream and downstream flow paths of the generated gas; A filter device having a filter element that collects the granular material in the generated gas through both openings of the container burns carbon contained in the granular material collected in the filter element. A method of regenerating the filter device by introducing a regeneration gas,
In a state where the internal pressure of the container is set to a preset pressure higher than atmospheric pressure, the temperature of the regeneration gas is controlled so that the internal temperature of the container becomes a preset temperature of less than 400 ° C. A method for regenerating a filter device to be put into a container. The method for regenerating a filter device according to claim 1,
A regeneration method for a filter device, wherein the oxygen concentration of the regeneration gas charged into the container is controlled to a preset concentration of 30 Vol.% Or less. The method for regenerating a filter device according to claim 2,
A method for regenerating a filter device, wherein at least one of the preset concentration of the oxygen concentration of the regeneration gas introduced into the container and the preset temperature of the internal temperature of the container are increased stepwise. The method for regenerating a filter device according to claim 2,
A filter that gradually increases one of the preset concentration of the oxygen concentration of the regeneration gas introduced into the container and the preset temperature of the internal temperature of the container and gradually decreases the other. Device regeneration method. The method for regenerating a filter device according to any one of claims 1 to 4,
After the regeneration gas is introduced into the container and the regeneration of the filter device is started, the temperature of the regeneration gas on the inlet side of the container and the temperature of the regeneration gas on the outlet side of the container are detected, A method for regenerating a filter device that terminates regeneration of the filter device when a difference between the detected inlet side temperature and outlet side temperature becomes smaller than a preset threshold value. A coal gasification furnace that partially gasifies coal to gasify, a generated gas flow path through which the generated gas generated in the coal gasification furnace flows, and a flow path provided in the generated gas flow path A filter device for collecting powder particles in the produced gas, the filter device comprising: a container provided with openings respectively communicating with the upstream and downstream flow paths of the produced gas; and And a filter element that collects the granular material across both openings,
A regeneration gas input flow path for supplying a regeneration gas for regenerating the filter device by burning carbon in the granular material collected by the filter element into the container, and the filter element introduced into the container A regeneration gas discharge passage for discharging the regeneration gas that has passed through
An inlet side temperature detector provided upstream of the filter element with respect to the flow of the regeneration gas inside the container, and a regeneration device provided in the regeneration gas input flow channel and flowing through the flow channel A temperature regulator for adjusting the gas temperature, a pressure detector for detecting the internal pressure of the filter device, a regeneration gas outlet valve provided in the regeneration gas discharge channel, and regeneration control of the filter device With a regeneration controller,
The regeneration controller controls a heating amount or a heat reduction amount in the temperature regulator so that an internal temperature of the filter device detected by the inlet side temperature detector becomes a preset temperature less than 400 ° C.,
The regeneration system of the filter apparatus which controls the valve opening degree of the said regeneration gas outlet valve so that the internal pressure of the said filter apparatus detected by the said pressure detector may become a preset pressure higher than atmospheric pressure. The regeneration system for a filter device according to claim 6,
An oxygen concentration detector provided in the regeneration gas input flow path, and an adjustment for supplying at least one adjustment gas of oxygen and nitrogen upstream of the oxygen concentration detector in the regeneration gas input flow path A gas input flow path,
The regeneration controller is a regeneration system for a filter device that controls the flow rate of the adjustment gas so that the oxygen concentration of the regeneration gas detected by the oxygen concentration detector becomes a preset concentration of 30 Vol.% Or less. . The regeneration system for a filter device according to claim 7,
The regeneration controller is configured such that at least one of the preset concentration of the oxygen concentration of the regeneration gas introduced into the container and the preset temperature of the internal temperature of the container is increased stepwise. The regeneration system of the filter apparatus which controls at least one of the flow volume of the said adjustment gas, and the temperature in the said temperature regulator. The regeneration system for a filter device according to claim 7,
The regeneration controller is configured such that one of the preset concentration of the oxygen concentration of the regeneration gas introduced into the container and the preset temperature of the internal temperature of the container increase stepwise. The adjustment gas is controlled so that at least one of the flow rate of the adjustment gas and the temperature in the temperature regulator is controlled, and the other of the oxygen concentration and the temperature of the regeneration gas introduced into the container is reduced stepwise. The regeneration system of the filter device controls the other of the flow rate and the temperature in the temperature regulator. The regeneration system for a filter device according to any one of claims 6 to 9,
An outlet side temperature detector provided in the regeneration gas discharge flow path;
The regeneration controller, after injecting the regeneration gas into the container and starting regeneration of the filter device, the temperature detected by the inlet side temperature detector and the temperature detected by the outlet side temperature detector A regeneration system for a filter device that terminates the regeneration of the filter device when the difference between and becomes smaller than a preset threshold value.

Images