JP6584464B2 - Stoker-type incinerator and control method thereof - Google Patents

Description

  The present invention relates to a stoker-type incinerator and a control method thereof.

  Conventionally, as shown in FIG. 13, the stoker type incinerator is generated in the unburned rich gas C having a high concentration of carbon monoxide and hydrocarbons generated upstream of the dry stoker 5x and the combustion stoker 5y and the post-combustion stoker 5z. The air-rich gas D enters the secondary combustion chamber 2b and is mixed and stirred by the secondary air supplied through the secondary air supply system 10 to be completely combusted. The conventional stoker combustion technology has been developed with an emphasis on promoting the combustion by efficiently mixing and stirring the unburned rich gas C and the air rich gas D. In FIG. 13, the code | symbol S shows the superheater and the code | symbol E has shown the economizer.

  As such a stoker combustion technique, for example, a technique (Patent Document 1) is known in which combustion is promoted by drawing an air-rich gas from above the post-combustion stoker 5z and blowing the drawn gas into the secondary combustion chamber 2b. .

  For mixing and stirring in the secondary combustion chamber 2b, in addition to blowing air as secondary air at several tens of meters / second, as described above, the gas above the post-combustion stoker 5z and further exhaust gas treatment equipment (not shown) The technology using the exhaust gas removed from the dust is known (Patent Documents 2 to 4 etc.).

JP 2006-250377 A JP 2001-241629 A Japanese Patent Laid-Open No. 2004-20071 JP 2010-249478 A

  However, the conventional stoker combustion technology described above is a technology that mixes and stirs combustion gas generated from waste, and does not contribute to stabilization of garbage combustion on the stoker. Therefore, there is a technology that stabilizes waste combustion on the stoker. It has been demanded.

  On a combustion stoker, waste that is hard to burn and a lot of plastic is mixed with waste that is easy to burn, and the dust is supplied while fluctuating over time. Therefore, it is difficult to say that the combustion is stable. Combustion in a stoker incinerator has a primary air ratio of about 0.7 to 1.2, and if this is taken as an index representing the amount of combustion in the primary combustion chamber, 70% or more of the combusted material is 1 It is burning in the next combustion chamber. Therefore, improving primary combustion to more uniform combustion is a means for suppressing the generation of nitrogen oxides and dioxins.

  Then, this invention sets it as the main objective to provide the stoker type incinerator which can control the combustion in a primary combustion chamber, and its control method.

To achieve the above object, a stoker-type incinerator according to the present invention includes a grate temperature measuring means for measuring a temperature distribution of a grate arranged in the stoker, and a fire gage measured by the grate temperature measuring means. A control device for controlling at least one of the supply amount of the primary air from the lower part of the stoker to each of the plurality of supply locations, the stoker speed, and the waste supply amount based on the temperature distribution information of the lattice temperature; Bei example, the temperature distribution information, the temperature distribution of the measured grate includes a mapping diagram mapped in shade or color to visualize the temperature distribution information of the grate temperature, the temperature of the grate temperature It includes distribution change information over time, and the change information includes a plurality of mapping diagrams arranged in time series at predetermined time intervals .

In another embodiment, the stoker type incinerator according to the present invention is measured by a grate temperature measuring means for measuring a temperature distribution of a grate arranged in the stoker, and the grate temperature measuring means. A control device that controls at least one or more of the supply amount of the primary air from the lower part of the stoker to each of a plurality of supply locations, the stoker speed, and the waste supply amount based on the temperature distribution information of the grate temperature; The temperature distribution information includes a graph that graphs the temperature distribution in the flow direction of the garbage to visualize the temperature distribution of the measured grate, and the temperature distribution information of the grate temperature includes the grate It includes the time-dependent change information of the temperature distribution of the temperature, and the time-change information includes a plurality of the graphs arranged in time series at predetermined time intervals .

  In one embodiment, the grate temperature measuring means includes a thermocouple attached to the lower surface of the grate.

  In one embodiment, the grate temperature measuring means includes a radiation thermometer that measures a lower surface temperature of the grate.

In order to achieve the above object, a method for controlling a stoker-type incinerator according to the present invention includes a step of measuring a temperature distribution of a grate arranged in the stoker, and a visualization of the measured temperature distribution of the grate. Obtaining a mapping diagram mapped in shades or colors, obtaining a plurality of the mapping diagrams at a predetermined time interval, obtaining a plurality of the mapping diagrams arranged in time series for each predetermined time interval, and a predetermined Based on the plurality of mapping diagrams arranged in time series after each time interval , at least one of the supply amount of the primary air from the lower portion of the stoker to each of the plurality of supply locations, the stoker speed, and the waste supply amount Controlling one or more. In one embodiment, a method for controlling a stoker-type incinerator according to the present invention includes a step of measuring a temperature distribution of a grate arranged in the stoker, and a waste stream for visualizing the measured temperature distribution of the grate. Obtaining a graph in which the temperature distribution is graphed in a direction, obtaining a plurality of the graphs at predetermined time intervals, obtaining a plurality of graphs arranged in time series at each predetermined time interval, and at each predetermined time interval A step of controlling at least one or more of a supply amount, a stalker speed, and a waste supply amount of primary air from a lower portion of the stoker to each of a plurality of supply locations based on the plurality of graphs arranged in time series. And including.

  According to the present invention, by measuring the temperature distribution of the grate of the stoker-type incinerator, the combustion state on the grate can be grasped, and the primary combustion chamber can be controlled to a desired combustion state. It becomes possible and stable combustion becomes possible.

It is a schematic block diagram which shows the stoker type incinerator which concerns on this invention. It is a partial cross section side view of a movable grate and a fixed grate of a stoker type incinerator. It is a fragmentary sectional side view which shows the state which has the movable grate of FIG. 2 in another operation position. It is a partial section perspective view showing a stoker type incinerator. It is the top view which represented typically the stoker of the stoker type incinerator. It is the top view which showed the range which supplies the primary air of the combustion stoker of FIG. 5 by dividing into four. It is a mapping figure which shows the grate temperature distribution of a stalker corresponding to the shade of a gray scale for every temperature. It is the mapping figure which added description to the mapping of FIG. FIG. 8 is a mapping diagram in which the mapping diagrams of FIG. 7 are arranged in time series. FIG. 8 is a mapping diagram in which the mapping diagram of FIG. 7 is arranged in another time series. FIG. 6 is a plan view in which a description for graphing the stoker's grate temperature distribution is added to the plan view of FIG. 5. It is the graph which graphed the grate temperature distribution of the stoker compared with the mapping figure. It is a longitudinal cross-sectional view which shows the internal structure of the conventional stoker type incinerator.

  Embodiments of the present invention will be described below with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same same or similar component through all drawings and all embodiment including a prior art.

  As shown in FIG. 1, a stoker type incinerator 1 includes a furnace body 2, a hopper 3, a dust feeder 4, a stoker 5, a main ash chute 6, a waste heat boiler 7, a primary air supply system 8, and a secondary air supply. System 10 etc. are provided.

  The illustrated stalker 5 is a stepped stalker in which a movable grate 5a and a fixed grate 5b are alternately arranged in a staircase, and the trash is agitated by reciprocating the movable grate 5a by a stalker driving device 5c. Transport while. The speed at which the movable grate 5 a reciprocates, that is, the stalker speed, is controlled by the control device 11. The stalker 5 is divided into a dry stoker 5x in the drying zone, a combustion stoker 5y in the combustion zone, and a post-combustion stoker 5z in the post-combustion zone from the upstream side to the downstream side.

  Air boxes 12a, 12b, 12c, 12d, 12e, and 12f for supplying primary air are provided at the lower portions of the dry stoker 5x, the combustion stoker 5y, and the post-combustion stoker 5z, respectively. A primary air supply system 8 is connected to each of the wind boxes 12a to 12f.

  The primary air supply system 8 is a device that feeds primary air required for combustion into the furnace, and is configured by a forced air blower 8a, an air preheater 8b, an air duct 8c, an air volume control means 8d such as a damper, and the like. . The secondary air is sent to the secondary combustion chamber 2b above the primary combustion chamber 2a through the secondary air supply system 10.

  The control device 11 controls the supply amount of the primary air by the control of the flow rate control means 8d or the rotational speed control of the electric motor of the forced air blower 8a. The control device 11 individually controls a plurality of flow rate control means 8a, for example, changing the primary air supply amount between the combustion zone and the post-combustion zone. Air can be supplied.

  The dust feeding device 4 in the illustrated example is a pusher system that pushes the dust in the hopper 3 into the furnace by the reciprocation of the pusher 4a, and the control device 11 controls the stroke, operating speed, and operating interval of the pusher 4a. Thus, the amount of dust supply is controlled. The pusher 4a reciprocates by a pusher drive device 4b such as a hydraulic cylinder.

  The stoker-type incinerator 1 includes a grate temperature measuring unit that measures the temperature distribution of the lower surfaces of the movable grate 5a and the fixed grate 5b. The grate temperature measuring means can be configured, for example, by attaching a thermocouple (not shown) to appropriate locations on the lower surfaces of the movable grate 5a and the fixed grate 5b over the entire area of the stoker 5. Alternatively, the grate temperature measuring means can be constituted by a radiation thermometer (not shown) that measures the lower surface temperature of the movable grate 5a and the fixed grate 5b. The temperature of both the movable grate 5a and the fixed grate 5b may be measured, or the temperature of only the fixed grate 5b or only the movable grate 5a may be measured.

  Although dust is burning on the grate, the lower surface (back side surface) of the grate is only supplied with primary air, and the grate temperature can be easily measured from the lower surface of the grate. .

  Although not shown, the grate temperature measuring means is not limited to the lower surface of the grate, for example, by embedding a thermocouple in a high-temperature anti-corrosive metal material constituting the grate, etc. It is also possible to measure the temperature.

  FIG. 5 is a plan view of the stoker 5 as viewed from above. The stalkers 5 are stepped when viewed from the side, and are arranged like a grid in plan view. FIG. 6 shows an example of division of primary air supplied from under the stoker 5 (see FIG. 1), and the primary air supplied to the combustion stoker 5y is divided into four by the wind boxes 12b, 12c, 12d, and 12e. This is an example. The thick frame in FIG. 5 corresponds to the partition walls of the wind boxes 12b, 12c, 12d, and 12e.

  FIG. 7 is a diagram in which the temperature of all of the grate (movable grate 5a and fixed grate 5b) is measured and mapped to visualize the temperature distribution of the grate by associating grayscale shades for each temperature. It is. In this gray scale mapping diagram, the color is darker as the temperature is lower, and the color is lighter (lighter) as the temperature is higher. Instead of grayscale mapping, it can also be displayed with color mapping.

  The part where the combustion is most active becomes the highest temperature, and the combustion state of the entire stoker can be grasped from this temperature distribution. That is, the information shown in FIG. 8 can be read from this temperature distribution.

  By measuring the grate temperature in this way, the combustion state on the stoker can be read directly. Therefore, for example, if a large amount of primary air is supplied to a portion that is actively burning or a portion that begins to burn, the portion that is actively burning can be moved upstream of the garbage flow.

  The primary air supply position and the supply amount are controlled by controlling each of the air volume control means 8d for controlling the primary air supply quantity to each of the wind boxes 12a to 12f as a plurality of primary air supply locations. This can be done.

  In addition, by measuring the grate temperature over time, it becomes possible to detect changes in the combustion state from the state before the current combustion state to the current state, thereby optimizing the combustion state. be able to.

  FIG. 9 shows an example of the temporal change of the grate temperature distribution. In FIG. 9, “the state one hour ago” was the most active combustion state (combustion center) near the center of the combustion stalker, but “the state 30 minutes ago” moved the combustion center slightly downstream, The state of "is a state in which the combustion center is lowered from the most downstream of the combustion stalker to the vicinity of the upstream of the post-combustion stalker.

  Here, when the temperature distribution of the dry stoker shown in FIG. 9 is observed, the area of the dark portion (low temperature portion) indicated by the arrow G of the dry stoker is large from “the state before 1 hour” to “the state before 30 minutes”. It turns out that the nature of the garbage has changed to a non-burnable garbage rich in moisture.

  For example, if it is desired to maintain the “state 30 minutes before” in FIG. 9, air is supplied near the combustion center and near the start of combustion (combustion stoker air b and c in FIG. 6) in the “30 minutes ago” stage. By supplying a large amount, the combustion of that portion is made more vigorous, and the “current state” combustion center in FIG. 9 does not move downstream, and the “state 30 minutes ago” can be maintained.

  In the above example, the air supply amount is controlled to optimize the combustion state. However, if the waste quality is deteriorated (waste that is hard to burn with much moisture), the residence time of the waste in the furnace is increased. Therefore, it is possible to maintain the combustion state by slowing the stalker speed or reducing the amount of dust supply. Of course, it is also possible to control by combining the primary air blowing position, the primary air supply amount, and the stalker speed.

  By measuring the grate temperature as described above, it is possible to detect the combustion state, and it is possible to predict the state of the waste quality (whether it is easy to burn or difficult to burn) from the change over time, and stable combustion Can be realized.

  FIG. 10 shows another example of the change over time in the grate temperature distribution. In FIG. 10, the “state one hour ago” was the most prominent combustion state (combustion center) in the vicinity of the most downstream of the combustion stalker, but the “state 30 minutes ago” moved the combustion center slightly upstream, In the state of "," the combustion center has shifted to the upstream side up to the vicinity of the combustion stalker center.

  Here, the temperature distribution of the dry stoker shown in FIG. 10 shows that the area of the low temperature portion (G) of the dry stoker is decreasing from “1 hour ago” to “30 minutes ago”. It can be seen that the properties are changing to flammable garbage with low moisture and high plastic content. If it is desired to maintain the “state 30 minutes before” in FIG. 10, the supply amounts near the combustion center and near the start of combustion (combustion stoker air b and c in FIG. 6) are set in the “state 30 minutes ago” stage. By supplying less, it becomes possible to suppress the combustion of the part. As described above, the stalker speed and the waste supply amount may be controlled. Needless to say, the control may be a combination of the primary air feeding position, the primary air supply amount, and the stalker speed.

  In the above embodiment, the grate temperature is measured and the temperature distribution by mapping is expressed to express the data. However, as another embodiment, as shown in FIGS. It is also possible to graph the temperature distribution in the flow direction and predict the combustion center from the average value of the plurality of graphs (FIG. 12). A plurality of thin line graphs in the graph of FIG. 12 are the temperature distributions of the plurality of chain lines shown in FIG. 11, and a thick line graph of the graph of FIG. 12 shows an average value thereof. Thus, even if it represents with a graph, since it can understand that the combustion center is moving temporally, calculation of the position which supplies primary air is attained.

  In the said embodiment, although the example which measures the temperature of all the grate was shown, since it is sufficient if a temperature distribution can be measured, for example, it measures with the odd number row (one skip row) of the fixed grate 5b. Preferably, the temperature may be measured in the range of at least 50% or more for each of the drying zone, the combustion zone, and the post-combustion zone.

  In the illustrated example, the air supplied to the combustion stoker is supplied from four divided sections. However, if the number of divisions for supplying primary air is increased, more stable control is possible. For example, by dividing in a direction (stoker width direction) intersecting with the direction of dust flow and dividing into eight parts, it is possible to cope with a case where the combustion state is different in the stalker width direction.

  Although not shown in detail, the steam temperature, combustion chamber gas temperature, exhaust gas analysis value, etc. of the waste heat boiler 7 are detected, and these detection data are also controlled together with the grate temperature information measured by the grate temperature measuring means. Supplied to the device 11.

  The control device 11 is set with a target incineration amount, a target evaporation amount, an excess air ratio, and the like, and a desired grate temperature distribution is set, so-called automatic combustion control (fuzzy control system, autoregressive model control system, etc.) ACC (Automatic Combustion Control) can be performed. In automatic combustion control, the stoker speed, dust supply amount, and primary air supply are set so that the desired grate temperature distribution is set based on the grate temperature distribution information measured by the grate temperature measuring means. The position and / or primary air supply is controlled.

  The desired grate temperature distribution can be set, for example, by providing an appropriate temperature range for each zone, that is, for each section of the wind box. For example, referring to FIG. 6, zone I for supplying dry stoker air is 100 to 200 ° C., zone II for supplying combustion stoker air a is 150 to 250 ° C., and zone III for supplying combustion stoker air b is 250 to 350 ° C., Zone IV to which combustion stoker air c is supplied is 250 to 350 ° C., Zone V to which combustion stoker air d is supplied is 200 to 300 ° C., and Zone VI to which post combustion stoker air is supplied is 150 to An appropriate temperature range such as 250 ° C. is set. In this case, for example, the average temperature for each zone measured by the grate temperature measuring means can be controlled as an index, or the maximum temperature and the minimum temperature among the measurement points in the zone can be controlled as an index. it can.

  The grate temperature distribution preset (stored) in the control device 11 has appropriate temperature range information, and the control device 11 basically eliminates it if it deviates from the appropriate temperature range. The primary air (dry stoker air, combustion stoker air a to d, and post-combustion stoker air) is increased or decreased as described above. Further, the control device 11 calculates the peak position of the measured temperature, and returns the peak position to each of a plurality of primary air supply locations from the lower part of the stoker so as to return the peak position to an appropriate (preset) position. At least one of the supply amount, the stoker speed, and the waste supply amount.

  Further, the control device 11 calculates a time (moving time) in which the peak position of the temperature measured by the grate temperature measuring means (for example, the peak position in the graph of the average temperature in FIG. 12) shifts, and moves the garbage from the obtained time. It is also possible to obtain the speed and adjust the stalker speed so that the peak position of the measured temperature is an appropriate (preset) position.

  Moreover, the control apparatus 11 calculates the degree (inclination) of the rise or fall of the temperature of each grate measured by the grate temperature measuring means, and the primary air from the lower part of the stoker is calculated according to the degree (inclination). At least one of the supply amount, the stalker speed, and the waste supply amount to each of the plurality of supply points is controlled steeply when the inclination is large, and slowly controlled when the inclination is small. You can also.

  The present invention is not construed as being limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention is applicable not only to waste incineration but also to a stoker-type incinerator for biomass boilers and sewage sludge treatment.

DESCRIPTION OF SYMBOLS 1 Stoker type incinerator 2a Primary combustion chamber 2b Secondary combustion chamber 4 Dust supply device 5 Stoker 5a Movable grate 5b Fixed grate 5c Stoker drive device 11 Control device

Claims (6)

Grate temperature measuring means for measuring the temperature distribution of the grate arranged in the stalker,
Based on the temperature distribution information of the grate temperature measured by the grate temperature measuring means, at least a supply amount of the primary air from the lower part of the stoker to each of a plurality of supply locations, a stoker speed, and a dust supply amount A control device for controlling one or more;
Bei to give a,
The temperature distribution information includes a mapping diagram mapped in shading or color to visualize the temperature distribution of the measured grate,
The temperature distribution information of the grate temperature includes time-dependent change information of the temperature distribution of the grate temperature,
The stoker-type incinerator characterized in that the time-dependent change information includes a plurality of the mapping diagrams arranged in time series at predetermined time intervals . Grate temperature measuring means for measuring the temperature distribution of the grate arranged in the stalker,
Based on the temperature distribution information of the grate temperature measured by the grate temperature measuring means, at least a supply amount of the primary air from the lower part of the stoker to each of a plurality of supply locations, a stoker speed, and a dust supply amount A control device for controlling one or more;
Bei to give a,
The temperature distribution information includes a graph that graphs the temperature distribution in the direction of garbage flow in order to visualize the temperature distribution of the measured grate,
The temperature distribution information of the grate temperature includes time-dependent change information of the temperature distribution of the grate temperature,
The stoker-type incinerator , wherein the time-dependent change information includes a plurality of the graphs arranged in time series at predetermined time intervals .   The stoker-type incinerator according to claim 1 or 2, wherein the grate temperature measuring means includes a thermocouple attached to a lower surface of the grate.   The stoker-type incinerator according to claim 1 or 2, wherein the grate temperature measuring means includes a radiation thermometer that measures a lower surface temperature of the grate. Measuring the temperature distribution of the grate arranged in the stalker;
Obtaining a mapping diagram mapped in shades or colors to visualize the temperature distribution of the measured grate;
Obtaining a plurality of the mapping diagrams at a predetermined time interval and obtaining a plurality of the mapping diagrams arranged in time series at a predetermined time interval;
Based on the plurality of mapping diagrams arranged in time series at predetermined time intervals, at least one of the supply amount of the primary air from the lower portion of the stoker to each of the plurality of supply locations, the stoker speed, and the waste supply amount A method for controlling a stoker incinerator, comprising the step of controlling one or more. Measuring the temperature distribution of the grate arranged in the stalker;
Obtaining a graph graphing the temperature distribution in the direction of garbage flow in order to visualize the temperature distribution of the measured grate;
Obtaining a plurality of the graphs at a predetermined time interval, obtaining a plurality of the graphs arranged in time series for each predetermined time interval; and
Based on the plurality of graphs arranged in time series at predetermined time intervals, at least one of the supply amount of the primary air from the lower part of the stoker to each of the plurality of supply locations, the stoker speed, and the waste supply amount A method for controlling a stoker-type incinerator, comprising the steps of controlling the above .