JP7209814B2 - Exhaust heat recovery system - Google Patents

Description

TECHNICAL FIELD The present invention relates to an exhaust heat recovery system for recovering heat from exhaust gas in a cement manufacturing process.

The cement manufacturing process can be broadly divided into the raw material process of drying, pulverizing, and blending the cement raw materials, the firing process of firing the raw materials into clinker, an intermediate product, and the finishing process of adding gypsum to the clinker and pulverizing it into cement. consists of Among these, in the firing process, the cement raw material is first preheated with a preheater, then calcined in a calcining furnace, then calcined in a kiln furnace, and finally in an air quenching cooler (hereinafter "AQC"). cooled in AQC generates a large amount of exhaust gas at 250 to 300°C. BACKGROUND ART Conventionally, there has been known an exhaust heat recovery system that introduces exhaust gas generated by an AQC into a boiler, recovers the exhaust heat, and generates power using the recovered heat.

For example, FIG. 3 of Patent Document 1 discloses an exhaust heat recovery system including a high temperature exhaust gas line connected to a high temperature section of AQC and a low temperature exhaust gas line connected to a low temperature section of AQC. The high temperature exhaust gas line discharges the relatively high temperature (eg 360° C. on average) exhaust gas in the AQC, and the low temperature exhaust gas line discharges the relatively low temperature (eg 110° C. on average) exhaust gas in the AQC. The flue gas discharged from the AQC through the hot flue gas line is led to the boiler. In the boiler, superheated steam is generated by the heat of the exhaust gas, and the superheated steam is used for power generation in the steam turbine generator. Exhaust gas from which heat has been recovered by the boiler joins the exhaust gas discharged from the AQC through the low-temperature exhaust gas line, passes through the dust collector, and is released into the atmosphere through the chimney.

Japanese Patent No. 5897302

By the way, clinker fired in a kiln is usually dropped from the kiln into the AQC by its own weight. Therefore, the amount of clinker supplied to the AQC fluctuates, and as a result, the temperature of the exhaust gas generated in the AQC fluctuates. Such fluctuations in the temperature of the exhaust gas within the AQC affect the increase or decrease in the amount of heat recovered by the boiler. Therefore, a system capable of efficiently recovering heat without depending on temperature fluctuations in the AQC is desired.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an exhaust heat recovery system capable of efficiently recovering heat in an AQC boiler even when the temperature of the exhaust gas in the AQC fluctuates.

In order to solve the above problems, an exhaust heat recovery system according to one aspect of the present invention includes a kiln for firing cement raw materials and an air quenching cooler (hereinafter referred to as , AQC), an exhaust heat recovery system for recovering heat from the exhaust gas generated in the AQC, a boiler for recovering heat from the exhaust gas generated in the AQC, and a predetermined high temperature of the AQC A first exhaust gas line that guides the exhaust gas discharged from the unit to the inlet of the boiler, a release facility that releases the exhaust gas after heat is recovered by the boiler into the atmosphere, and a release facility that releases the exhaust gas discharged from the outlet of the boiler. and a second exhaust gas line that joins the exhaust gas discharged from the low temperature part of the AQC located downstream from the high temperature part in the direction of conveying the baked product to the release line, and the first exhaust gas line a provided thermometer, at least one flow control device for adjusting the flow rate of the exhaust gas flowing through at least one of the first exhaust gas line and the second exhaust gas line, and bringing the measured value of the thermometer close to a predetermined set value. and a command generating device for generating a command value for adjusting the at least one flow control device such that:

According to the above system, even if the temperature of the exhaust gas in the AQC fluctuates, by adjusting the at least one flow control device according to the command value generated by the command generation device, the temperature of the gas flowing into the boiler is kept constant. (that is, at the set value). As a result, even when the temperature of the exhaust gas in the AQC fluctuates, heat can be efficiently recovered by the boiler.

In the above system, when the measured value is higher than the set value, the command generation device generates the command value for reducing the flow rate of exhaust gas flowing through at least the second exhaust gas line, and the measured value If it is lower than the set value, the command value may be generated to increase the flow rate of exhaust gas flowing through at least the second exhaust gas line.

For example, in the system described above, the command generator controls the at least one flow regulator based on the generated command value.

Alternatively, for example, the above system includes an operation device that receives an operator's operation and generates an operation command, a control device that controls the at least one flow control device based on the operation command, and the command generation device. and an output device for outputting an operation instruction corresponding to the given command value. According to this configuration, in a system in which at least one flow control device is adjusted by an operator's operation, the operation instruction corresponding to the command value generated by the command generation device is output to the output device. Therefore, the operator can be guided to operate the operating device to keep the temperature of the gas flowing into the boiler constant.

The above system includes an introduction line that is connected to the first exhaust gas line and introduces a low-temperature gas having a lower temperature than the exhaust gas discharged from the high-temperature part of the AQC into the first exhaust gas line; and a switching device, wherein the command generation device generates a command value to keep the switching device closed when the measured value of the thermometer is equal to or lower than a predetermined threshold value higher than the set value. A command value for opening the switching device may be generated when the temperature measured by the thermometer exceeds the threshold value. According to this configuration, by adjusting the third damper according to the generated opening command, it is possible to prevent gas exceeding the allowable temperature from flowing into the boiler.

In the above system, the thermometer is a first thermometer, and a second thermometer is provided upstream in the direction in which the baked product is conveyed from the high temperature section of the AQC, and the command generation device may predict the temperature of the flue gas at the inlet of the boiler after a predetermined time has elapsed from the present time based on the measured value of the second thermometer.

ADVANTAGE OF THE INVENTION According to this invention, even when the temperature of the waste gas in AQC fluctuates, the exhaust heat recovery system which can collect|recover heat efficiently by a boiler can be provided.

FIG. 1 is a diagram showing a schematic configuration of a cement burning plant including an exhaust heat recovery system according to one embodiment of the present invention. FIG. 2 is a block diagram of damper control in the exhaust heat recovery system shown in FIG. FIG. 3 is a block diagram of damper control in the exhaust heat recovery system according to Modification 1. As shown in FIG. FIG. 4 is a block diagram of damper control in the exhaust heat recovery system according to Modification 2. As shown in FIG.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a cement burning facility 1 including an exhaust heat recovery system 2 according to this embodiment.

[Cement firing equipment]
As mentioned above, the cement manufacturing process consists of a raw material process, a calcining process and a finishing process. The cement firing equipment 1 shown in FIG. 1 is responsible for the firing process of these, and powder raw materials obtained by drying, pulverizing, and blending limestone, clay, etc. in the raw material process (hereinafter referred to as "cement raw materials") ) to burn clinker, which is an intermediate product. The cement firing facility 1 includes a preheater 11, a calciner 12, a rotary kiln 13, and an AQC 14.

The preheater 11 includes multiple stages of cyclones connected in series. In the preheater 11, exhaust heat from the rotary kiln 13 moves from the bottom cyclone to the top cyclone, and the cement raw material moves from the top cyclone to the bottom cyclone. The lowermost cyclone of the preheater 11 is connected to the calcining furnace 12 .

In the calcining furnace 12, the cement raw material coming out of the preheater 11 is calcined in an atmosphere of about 900°C. The calcining furnace 12 is connected to a calcining furnace bleed line 12 a for sending exhaust heat from the AQC 14 to the calcining furnace 12 and a fuel supply line 12 b for supplying fuel and the like to the calcining furnace 12 . An outlet of the calcining furnace 12 is connected to an inlet of the rotary kiln 13 .

The rotary kiln 13 is a horizontally long cylindrical rotary kiln, and is installed with a slight slope from the raw material inlet toward the raw material outlet. In the rotary kiln 13 , the cement raw material preheated and calcined by the preheater 11 and the calcining furnace 12 is calcined by exhaust heat of the AQC 14 and combustion gas of the burner 100 . The outlet of the rotary kiln 13 is connected to the inlet 14a of the AQC 14.

The AQC 14 quenches the high temperature (for example, about 1400° C.) baked product from the rotary kiln 13 . Specifically, the baked material dropped into the AQC 14 from the outlet of the rotary kiln 13 is conveyed toward the outlet 14b by a conveyor (not shown) inside the AQC 14 . The baked product is cooled by blowing cooling air from below the conveyor while it is conveyed by the conveyor. After being cooled by the AQC 14, the clinker, ie, the clinker, is conveyed to a clinker silo by a clinker conveyor (not shown) after coming out of the outlet 14b.

The cooling air blown against the high-temperature fired product in the AQC 14 becomes high-temperature exhaust gas. The gas temperature in the AQC 14 forms a distribution that becomes lower as it approaches the exit 14b along the conveying direction of the baked product. For example, the gas temperature near the inlet 14a of the AQC 14 is approximately 1350°C, and the gas temperature near the outlet 14b of the AQC 14 is approximately 100°C. However, since the amount of clinker supplied to the AQC 14 fluctuates as described above, the temperature of the exhaust gas in the AQC 14 fluctuates.

[Exhaust heat recovery system]
The cement burning facility 1 further includes an exhaust heat recovery system 2 that recovers heat from the exhaust gas from the high temperature part 14 c of the AQC 14 and the exhaust gas generated by the preheater 11 . The exhaust heat recovery system 2 includes an air quenching cooler boiler (hereinafter referred to as AQC boiler) 30 , a control device 50 and a steam turbine generator 60 .

The AQC boiler 30 is a boiler that uses exhaust gas generated by the AQC 14 as a heating medium. The AQC boiler 30 comprises a boiler body 31 having a gas inlet 31a and a gas outlet 31b. In the boiler main body 31, a superheater 32, an evaporator 33, and a preheater (economizer) 34, which are heat exchangers, are installed in this order from a gas inlet 31a toward a gas outlet 31b. A steam drum 35 is attached to the boiler main body 31 .

A gas inlet 31 a of the boiler main body 31 is connected to a first exhaust gas line 43 extending from the high temperature portion 14 c of the AQC 14 . The high-temperature portion 14c of the AQC 14 is a portion of the AQC 14 where the exhaust gas temperature is relatively high (for example, approximately 350°C). For example, the average temperature of the high temperature part 14 c of the AQC 14 is within the allowable temperature range of the AQC boiler 30 . Since the upstream end of the first exhaust gas line 43 is positioned in the high temperature portion 14c of the AQC 14, the relatively high temperature exhaust gas is guided from the AQC 14 to the AQC boiler 30 through the first exhaust gas line 43, and the heating medium of the AQC boiler 30 used as

The AQC 14 is connected to the calciner bleed line 12a described above. The calcination furnace bleed line 12a is connected to the AQC 14 upstream of the position where the first exhaust gas line 43 and the AQC 14 are connected in the conveying direction of the fired material. Therefore, exhaust gas having a higher temperature (for example, about 600° C.) than the temperature of the exhaust gas discharged from the first exhaust gas line 43 is extracted from the calciner extraction line 12a.

Further, a thermometer 101 (corresponding to the "second thermometer" of the present invention) is provided on the upstream side of the high temperature portion 14c of the AQC 14 in the conveying direction of the baked product. The measured value of thermometer 101 is sent to control device 50 .

A gas outlet 31b of the boiler main body 31 is connected to a second release line 44 (corresponding to the "release line" of the present invention). The second discharge line 44 is provided with a dust collector 36, an exhaust fan 37, and a chimney 38 (corresponding to the "discharge equipment" of the present invention) in this order from upstream to downstream of the exhaust gas flow. Exhaust gas after heat exchange in the AQC boiler 30 passes through the dust collector 36 and is released to the atmosphere from the chimney 38 .

A second exhaust gas line 45 extends from the low temperature portion 14d of the AQC 14 . The low-temperature portion 14d of the AQC 14 is a portion of the AQC 14 where the exhaust gas temperature is relatively low (for example, about 150° C.), and is located downstream of the high-temperature portion 14c of the AQC 14 in the conveying direction of the baked product. Relatively low-temperature exhaust gas is discharged from the AQC 14 through the second exhaust gas line 45 by positioning the upstream end of the second exhaust gas line 45 in the low temperature portion 14 d of the AQC 14 . A downstream end of the second exhaust gas line 45 is connected between the AQC boiler 30 and the dust collector 36 in the second discharge line 44 . That is, the exhaust gas discharged from the low temperature part 14d of the AQC 14 passes through the second exhaust gas line 45, joins the exhaust gas emitted from the outlet 31b of the AQC boiler 30, passes through the dust collector 36, and is released to the atmosphere from the chimney 38. be done.

The first exhaust gas line 43 is provided with a thermometer 51 (corresponding to the “thermometer” and “first thermometer” of the present invention) for measuring the temperature of the exhaust gas led to the AQC boiler 30 . A first damper 52 is provided upstream of the thermometer 51 in the first exhaust gas line 43 . A second damper 53 is provided in the second exhaust gas line 45 . An introduction line 46 is connected between the first damper 52 and the thermometer 51 in the first exhaust gas line 43 . A third damper 54 is provided in the introduction line 46 . In this embodiment, the first damper 52, the second damper 53, and the third damper 54 are controlled by the control device 50 to adjust their opening degrees. The details of the control method by the control device 50 will be described later.

The steam turbine generator 60 has a steam turbine 61 and a generator 62 . The steam turbine 61 is driven by the supplied steam.

The control device 50 controls the first damper 52 , the second damper 53 and the third damper 54 based on the temperature measured by the thermometer 51 . FIG. 2 shows a block diagram of damper control in the exhaust heat recovery system 2. As shown in FIG. Controller 50 includes a processor and volatile and non-volatile memory. The processor is composed of a CPU, an MPU, a GPU, etc., and reads out and executes various programs stored in the memory to realize control according to the control target and various functional units to be described later.

FIG. 2 shows the functional configuration of the control device 50. As shown in FIG. The control device 50 includes an opening degree command generation unit 50a and a damper control unit 50b, and these functional units 50a and 50b are constructed by combining hardware such as the CPU and software stored in the ROM or the like. . The control device 50 may not be composed of one unit, and may be composed of a plurality of units. The opening degree command generation unit 50 a generates opening degree command values, which are opening degree information of the first damper 52 , the second damper 53 and the third damper 54 , based on the measured value of the thermometer 51 . The damper control unit 50b controls the first damper 52, the second damper 53 and the third damper 54 based on the opening command generated by the opening command generating unit 50a.

The damper control by the control device 50 will be described in more detail below.

Assuming that the opening degrees of the first damper 52 and the second damper 53 are constant, the temperature of the exhaust gas led to the AQC boiler 30 through the first exhaust gas line 43 also fluctuates depending on the temperature fluctuation of the exhaust gas in the AQC 14. do. In this embodiment, the control device 50 controls at least one of the first damper 52 and the second damper 53 so that the temperature of the exhaust gas led to the AQC boiler 30 is maintained at a predetermined temperature.

Specifically, the opening degree command generation unit 50a generates a command value ( opening command value). That is, the control device 50 functions as the "command generation device" of the present invention. Here, the predetermined set value T1 is set to a value (for example, 360°C) that is lower than the allowable upper limit (for example, 400°C) of the AQC boiler 30 and as close as possible to the allowable upper limit so that the heat of the exhaust gas in the AQC 14 can be recovered as much as possible. set.

An example of damper control by the control device 50 will be described. In the example described here, an example in which the control device 50 adjusts only the opening degree of the second damper 53 of the first damper 52 and the second damper 53 will be described. That is, in the example described here, the opening degree of the first damper 52 is fixed at a predetermined opening degree. In this example, the second damper 53 functions as a flow control device that controls the flow rate of the exhaust gas flowing through the second exhaust gas line 45, and corresponds to "at least one flow control device" of the present invention.

The damper control unit 50b adjusts the opening degree of the first damper 52 to a predetermined opening degree (for example, fully open). Further, during operation of the AQC boiler 30, the opening degree command generation unit 50a reduces the opening degree of the second damper 53 by a command value (open degree command). Then, the damper control unit 50b adjusts the opening degree of the second damper 53 based on the generated command value. By reducing the opening degree of the second damper 53, the amount of relatively low-temperature exhaust gas discharged from the AQC 14 through the second exhaust gas line 45 is reduced. As a result, the temperature of the exhaust gas discharged from the AQC 14 through the first exhaust gas line 43 is reduced, and the measured value T of the thermometer 51 can be brought close to the predetermined set value T1.

Further, the opening command generation unit 50a generates a command value (opening command) for increasing the opening of the second damper 53 when the measured value T of the thermometer 51 is lower than the predetermined set value T1. Then, the damper control unit 50b adjusts the opening degree of the second damper 53 based on the generated command value. As the degree of opening of the second damper 53 increases, the amount of relatively low-temperature exhaust gas discharged from the AQC 14 through the second exhaust gas line 45 increases. As a result, the temperature of the exhaust gas discharged from the AQC 14 through the first exhaust gas line 43 increases, and the measured value T of the thermometer 51 can be brought closer to the predetermined set value T1.

However, the damper control described above is merely an example. For example, the control device 50 may adjust the opening degrees of both the first damper 52 and the second damper 53 . In this case, the first damper 52 functions as a flow rate adjusting device that adjusts the flow rate of exhaust gas flowing through the first exhaust gas line 43, and the second damper 53 functions as a flow rate adjusting device that adjusts the flow rate of exhaust gas flowing through the second exhaust gas line 45. It works as a device. The first damper 52 and the second damper 53 correspond to "at least one flow control device" of the present invention.

When the control device 50 adjusts the opening degrees of both the first damper 52 and the second damper 53, the opening command generation unit 50a sets the , to generate a command value (opening command) for decreasing the opening of the second damper 53 and increasing the opening of the first damper 52 . Then, the damper control unit 50b adjusts the opening degrees of the first damper 52 and the second damper 53 based on the generated command value. Further, when the measured value T of the thermometer 51 is lower than the predetermined set value T1, the opening command generation unit 50a increases the opening of the second damper 53 and decreases the opening of the first damper 52. Generate command value (opening command). Then, the damper control unit 50b adjusts the opening degrees of the first damper 52 and the second damper 53 based on the generated command value.

Alternatively, the degree of opening of the second damper 53 may be fixed at a predetermined degree of opening, and the controller 50 may adjust only the degree of opening of the first damper 52 out of the first damper 52 and the second damper 53 . In this case, the first damper 52 functions as a flow rate adjusting device that adjusts the flow rate of the exhaust gas flowing through the first exhaust gas line 43 . The first damper 52 corresponds to "at least one flow control device" of the present invention.

When the control device 50 adjusts only the opening degree of the first damper 52, the opening degree command generation unit 50a adjusts the opening degree of the first damper 52 when the measured value T of the thermometer 51 is higher than the predetermined set value T1. Generates a command value (opening command) to increase the degree of opening. Then, the damper control unit 50b adjusts the opening of the first damper 52 based on the generated command value (opening command). Further, the opening command generation unit 50a generates a command value (opening command) to reduce the opening of the first damper 52 when the measured value T of the thermometer 51 is lower than the predetermined set value T1. . Then, the damper control unit 50b adjusts the opening degree of the first damper 52 based on the generated command value.

Furthermore, the control device 50 controls a third damper 54 provided in the introduction line 46 . The introduction line 46 is for introducing into the first exhaust gas line 43 a low temperature gas having a temperature lower than that of the exhaust gas discharged from the high temperature section 14 c in the AQC 14 . The low-temperature gas introduced into the first exhaust gas line 43 through the introduction line 46 is, for example, outside air.

The third damper 54 functions as an opening/closing device that opens and closes the introduction line 46 . The third damper 54 is normally closed during operation of the AQC boiler 30 . The third damper 54 is opened when the temperature of the exhaust gas led to the AQC boiler 30 is likely to exceed the allowable upper limit of the AQC boiler 30 despite the adjustment of the degree of opening of the second damper 53 . Specifically, when the measured value T of the thermometer 51 is equal to or lower than a predetermined threshold value T2 higher than the set value T1, the control device 50 keeps the third damper 54 closed. That is, when the measured value T of the thermometer 51 is equal to or less than the threshold value T2, the opening command generation unit 50a generates a command value (opening command) to fully close the third damper 54, and the damper control unit 50b closes the third damper 54 based on the generated command value. Here, the predetermined threshold value T2 is set between the allowable upper limit value and the set value T1 (for example, 390° C.) so that the temperature of the exhaust gas flowing into the boiler body 31 does not exceed the allowable upper limit value (for example, 400° C.) of the AQC boiler 30, for example. ). However, the predetermined threshold value T2 may be set to the allowable upper limit value of the AQC boiler 30.

Also, when the measured value T of the thermometer 51 exceeds the threshold value T2, the control device 50 opens the third damper 54 . That is, when the measured value T of the thermometer 51 exceeds the threshold value T2, the opening command generation unit 50a generates a command value (opening command) to fully open the third damper 54 or open it to a predetermined opening. Then, the damper control unit 50b opens the third damper 54 based on the generated command value. For example, the opening command generation unit 50a may generate a command value for opening the third damper 54 to the opening based on the measured value T when the measured value T of the thermometer 51 exceeds the threshold value T2.

As described above, according to the exhaust heat recovery system 2 according to the present embodiment, the opening command generator 50a controls the first damper 52 so that the measured value T of the thermometer 51 approaches the predetermined set value T1. and a command value (opening command value) for adjusting at least one of the second damper 53 and the second damper 53 . Then, the damper control unit 50b adjusts at least one of the first damper 52 and the second damper 53 based on the generated command value. Thereby, the temperature of the gas flowing into the AQC boiler 30 can be kept constant (that is, at the set value). As a result, heat can be efficiently recovered by the AQC boiler 30 even when the temperature of the exhaust gas in the AQC 14 fluctuates.

Further, in the present embodiment, when the measured value T of the thermometer 51 is equal to or lower than a predetermined threshold value T2 higher than the set value T1, the control device 50 keeps the third damper 54 closed and the thermometer 51 When the measured value T of exceeds the threshold value T2, the third damper 54 is opened. Thereby, it is possible to prevent the gas exceeding the allowable temperature from flowing into the AQC boiler 30 .

(Modification 1)
In the above embodiment, the control device 50 controls at least one of the first damper 52 and the second damper 53 so that the measured value T of the thermometer 51 approaches the predetermined set value T1, that is, performs so-called feedback control. explained. In addition to such feedback control, the control device 50 performs feedforward control for controlling at least one of the first damper 52 and the second damper 53 prior to temperature change in the measured value T of the thermometer 51. good too.

FIG. 3 is a block diagram of damper control in the exhaust heat recovery system according to Modification 1. As shown in FIG. The control device 50 includes an opening degree command generator 50a, a damper controller 50b, and a temperature predictor 50c. The temperature prediction unit 50c is constructed by combining hardware such as the CPU of the control device 50 and software stored in the ROM or the like.

The temperature prediction unit 50c is based on the measured value of the thermometer 101 provided on the upstream side in the conveying direction of the baked product from the high temperature part 14c in the AQC 14, after a predetermined time has elapsed from the current time (for example, 10 minutes later). predict the temperature of the exhaust gas at the inlet 31a of the . The prediction result is used to correct the command value generated by the opening degree command generator 50a.

The opening degree command generation unit 50a corrects the command value for bringing the current measurement value T of the thermometer 51 closer to the predetermined set value T1 based on the prediction result by the temperature prediction unit 50c. This correction is for suppressing deviation of the measured value T of the thermometer 51 from the predetermined set value T1 that may occur after the present time.

Specifically, when the temperature predicted by the temperature predicting unit 50c is higher than a predetermined set value T1, for example, the measured value T of the thermometer 51 will be displaced in a direction higher than the predetermined set value T1. is expected. Therefore, the opening degree command generation unit 50a reduces the temperature of the exhaust gas at the inlet 31a of the AQC boiler 30, in other words, reduces the opening degree of the second damper 53 and/or Alternatively, correction is made to increase the opening of the first damper 52 . For example, when the temperature predicted by the temperature prediction unit 50c is lower than the predetermined set value T1, the measured value T of the thermometer 51 is expected to become lower than the predetermined set value T1. Therefore, the opening degree command generation unit 50a increases the temperature of the exhaust gas at the inlet 31a of the AQC boiler 30, in other words, increases the opening degree of the second damper 53 and/or Alternatively, the opening degree of the first damper 52 is corrected to be reduced.

According to Modification 1, it is possible to quickly suppress the deviation of the measured value T of the thermometer 51 from the predetermined set value T1 even when the temperature of the exhaust gas in the AQC 14 suddenly fluctuates.

(Modification 2)
Further, in the above embodiment, the control device 50 generates a command value for adjusting at least one of the first damper 52 and the second damper 53 so that the measured value T of the thermometer 51 approaches the predetermined set value T1. and at least one of the first damper 52 and the second damper 53 is controlled based on the command value, but the present invention is not limited to this. For example, in the exhaust heat recovery system of the present invention, the degree of opening of at least one of the first damper 52 and the second damper 53 may be adjusted manually by the operator.

FIG. 4 is a block diagram of damper control in the exhaust heat recovery system according to Modification 2. As shown in FIG. In this exhaust heat recovery system, the degree of opening of at least one of the first damper 52 and the second damper 53 is adjusted by an operator's manual operation. This exhaust heat recovery system includes a command generation device 71 , an output device 72 , an operation device 73 and a control device 74 . Command generation device 71 generates a command value for adjusting at least one of first damper 52 and second damper 53 so that measured value T of thermometer 51 approaches predetermined set value T1. The output device 72 outputs operation instructions corresponding to the command values generated by the command generation device 71 . The operation device 73 receives an operator's operation and generates an operation command. The control device 74 controls at least one of the first damper 52 and the second damper 53 based on the operation command generated by the operation device 73 .

The output device 72 and the operating device 73 are arranged in the same space (for example, the operator's room of the cement burning equipment 1 ) 70 so that the operator can operate the operating device 73 according to the output of the output device 72 . The output device 72 may be an output mode capable of transmitting an operation instruction to the operation device 73 to the operator. There may be. For example, the output device 72 and the operation device 73 may be configured integrally, and may be touch screens, for example. Also, the command generation device 71 may be configured integrally with the output device 72 .

According to the exhaust heat recovery system according to Modification 2, the operation instruction corresponding to the command value generated by the command generation device 71 is output to the output device 72 . Therefore, the operator can be guided to operate the operating device 73 to keep the temperature of the gas flowing into the AQC boiler 30 constant. Therefore, in this modification 2 as well, heat can be efficiently recovered by the AQC boiler 30 as in the above-described embodiment.

The present invention is not limited to the embodiments and modifications described above, and various modifications are possible without departing from the gist of the invention.

For example, a combination of Modification 1 and Modification 2 is also included in the present invention. That is, in Modification 2, the command generating device 71 detects the temperature after a predetermined time (for example, 10 minutes later), the temperature of the exhaust gas at the inlet 31a of the AQC boiler 30 may be predicted. can be corrected.

Further, in the above-described embodiment, the first damper 52 and the second damper 53 are described as the flow control devices for controlling the flow rate of the exhaust gas flowing through the first exhaust gas line 43 and the second exhaust gas line 45, respectively. Although the third damper 54 has been described as an opening/closing device for opening/closing 46, the "flow control device" and "opening/closing device" in the present invention are not limited to dampers. For example, the "flow control device" and the "opening/closing device" in the present invention may be replaced with dampers, and known flow control devices such as valves and blowers may be used.

1: Cement firing equipment 2: Exhaust heat recovery system 13: Rotary kiln 14: Air quenching cooler 30: AQC boiler (boiler)
43: first exhaust gas line 44: second release line (release line)
45: Second exhaust gas line 46: Introduction line 50: Control device (command generation device)
51: Thermometer (first thermometer)
52: 1st damper (flow control device)
53: Second damper (flow control device)
54: Third damper (switching device)
71: command generation device 72: output device 73: operation device 74: control device 100: burner 101: thermometer (second thermometer)

Claims (5)

In a cement firing facility comprising a kiln for firing cement raw materials and an air quenching cooler (hereinafter referred to as AQC) for rapidly cooling the fired material fed from the kiln while conveying it, heat is recovered from the exhaust gas generated in the AQC. An exhaust heat recovery system,
a boiler that recovers heat from the exhaust gas generated by the AQC;
a first exhaust gas line that guides the exhaust gas discharged from the predetermined high temperature section of the AQC to the inlet of the boiler;
a discharge facility for discharging exhaust gas after heat is recovered by the boiler into the atmosphere;
a discharge line that guides the exhaust gas discharged from the outlet of the boiler to the discharge equipment;
a second exhaust gas line for joining the exhaust gas discharged from the low temperature part of the AQC located downstream from the high temperature part in the direction of conveying the fired product to the release line;
a thermometer provided in the first exhaust gas line;
at least one flow control device for controlling a flow rate of exhaust gas flowing through at least one of the first exhaust gas line and the second exhaust gas line;
a command generation device for generating a command value for adjusting the at least one flow control device such that the thermometer reading approaches a predetermined setpoint;
The thermometer is a first thermometer,
A second thermometer is provided on the upstream side in the direction of conveying the baked product from the high temperature part of the AQC,
The exhaust heat recovery system, wherein the command generating device predicts the temperature of the exhaust gas at the inlet of the boiler after a predetermined time has elapsed from the present time based on the measured value of the second thermometer. When the measured value of the first thermometer is higher than the set value, the command generation device generates the command value for reducing the flow rate of the exhaust gas flowing through at least the second exhaust gas line, and the first thermometer 2. The exhaust heat recovery system according to claim 1, wherein when the measured value of is lower than the set value, the command value is generated to increase the flow rate of exhaust gas flowing through at least the second exhaust gas line. 3. The exhaust heat recovery system according to claim 1, wherein said command generation device controls said at least one flow control device based on said generated command value. an operation device that receives an operator's operation and generates an operation command;
a control device for controlling the at least one flow control device based on the operational command;
3. The exhaust heat recovery system according to claim 1, further comprising an output device that outputs an operation instruction corresponding to the command value generated by the command generation device. an introduction line that is connected to the first exhaust gas line and introduces into the first exhaust gas line a low-temperature gas having a lower temperature than the exhaust gas discharged from the high-temperature portion of the AQC;
and an opening/closing device provided in the introduction line,
When the measured value of the first thermometer is equal to or lower than a predetermined threshold value higher than the set value, the command generation device generates a command value to keep the switching device closed, and The exhaust heat recovery system according to any one of claims 1 to 4, wherein when the temperature measured by the meter exceeds the threshold value, a command value for opening the switchgear is generated.

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