阅读说明：本技术 余热回收系统 (Waste heat recovery system ) 是由 竹中幸弘 宫内宽太 槙健良 山本修示 野副拓朗 田中寿典 雪冈敦史 李大明 张皓 于 2019-03-29 设计创作，主要内容包括：本发明提供一种余热回收系统。在AQC内的排气温度发生变动的情况下,也能利用AQC锅炉高效回收热。余热回收系统具有：锅炉,从AQC发生的排气中回收热；第1排气管,将从AQC的规定的高温部排出的排气向锅炉入口引导；排放设备,将由锅炉回收热之后的排气排放到大气中；排放管,将从锅炉出口排出的排气向排放设备引导；第2排气管,使从位于搬送烧结物的方向上的比高温部靠下游侧的位置的AQC的低温部排出的排气与排放管合流；温度计,设置于第1排气管；至少1个流量调节装置,对在第1排气管和第2排气管的至少一方流动的排气流量进行调节；以及指令生成装置,生成用于以使温度计的测量值接近规定设定值的方式对至少1个流量调节装置进行调节的指令值。(The invention provides a waste heat recovery system. The disclosed boiler can efficiently recover heat using an AQC boiler even when the exhaust gas temperature in the AQC fluctuates. The waste heat recovery system is provided with: a boiler recovering heat from the exhaust generated by the AQC; a 1 st exhaust pipe for guiding exhaust gas discharged from a predetermined high temperature part of the AQC to a boiler inlet; an exhaust device that exhausts the exhaust gas after heat is recovered by the boiler to the atmosphere; a discharge pipe guiding the exhaust gas discharged from the outlet of the boiler to a discharge device; a 2 nd exhaust pipe configured to join exhaust gas discharged from a low-temperature part of the AQC located downstream of the high-temperature part in a direction in which the sinter is conveyed, with the exhaust pipe; the thermometer is arranged on the 1 st exhaust pipe; at least 1 flow rate adjustment device for adjusting the flow rate of the exhaust gas flowing through at least one of the 1 st exhaust pipe and the 2 nd exhaust pipe; and a command generation device that generates a command value for adjusting at least 1 flow rate adjustment device so that the measurement value of the thermometer approaches a predetermined set value.)

1. A waste heat recovery system for recovering heat from exhaust gas generated by an Air Quenching Cooler (AQC) in a cement sintering facility having a kiln for sintering a cement raw material and the AQC as the AQC, the AQC being an air quenching cooler for conveying and rapidly cooling a sinter charged from the kiln, the waste heat recovery system comprising:

a boiler recovering heat from exhaust gas generated by the AQCs;

a 1 st exhaust pipe for guiding exhaust gas discharged from a predetermined high temperature part of the AQC to an inlet of the boiler;

an exhaust device that exhausts the exhaust gas after heat is recovered by the boiler to the atmosphere;

an exhaust pipe guiding exhaust gas discharged from an outlet of the boiler to the exhaust device;

a 2 nd exhaust pipe configured to join exhaust gas discharged from a low-temperature portion of the AQC located downstream of the high-temperature portion in a direction in which the sinter is conveyed, with the exhaust pipe;

a thermometer provided in the 1 st exhaust pipe;

at least 1 flow rate adjustment device that adjusts a flow rate of the exhaust gas flowing through at least one of the 1 st exhaust pipe and the 2 nd exhaust pipe; and

and an instruction generating device that generates an instruction value for adjusting the at least 1 flow rate adjusting device so that a measurement value of the thermometer approaches a predetermined set value.

2. The waste heat recovery system of claim 1,

the command generation device generates the command value for reducing at least the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe when the measured value is higher than the set value, and generates the command value for increasing at least the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe when the measured value is lower than the set value.

3. The waste heat recovery system according to claim 1 or 2,

the instruction generating means controls the at least 1 flow rate adjusting means according to the generated instruction value.

4. The heat recovery system according to claim 1 or 2, characterized by further having:

an operation device that receives an operation by an operator and generates an operation command;

the control device is used for controlling the at least 1 flow regulating device according to the operation instruction; and

an output device that outputs an operation instruction corresponding to the instruction value generated by the instruction generation device.

5. A heat recovery system according to any one of claims 1-4, characterized in that the heat recovery system further has:

an introduction pipe connected to the 1 st exhaust pipe and introducing a low-temperature gas having a temperature lower than a temperature of the exhaust gas discharged from the high-temperature portion of the AQC into the 1 st exhaust pipe; and

an opening/closing device provided in the introduction pipe,

the instruction generating device generates an instruction value for maintaining the state of closing the opening/closing device when a measured value of the thermometer is equal to or less than a predetermined threshold value higher than the set value, and generates an instruction value for opening the opening/closing device when a temperature measured by the thermometer exceeds the threshold value.

6. A waste heat recovery system according to any one of claims 1-5,

the thermometer is a 1 st thermometer and,

a 2 nd thermometer is arranged on the upstream side of the AQC in the direction of conveying the sinter from the high temperature part,

the command generation device predicts the temperature of the exhaust gas at the inlet of the boiler after a predetermined time has elapsed from the current time, based on the measurement value of the 2 nd thermometer.

Technical Field

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

Background

The cement manufacturing process is substantially composed of the following steps: a raw material step of drying, pulverizing and blending a cement raw material; a firing step of firing clinker as an intermediate product from the raw material; and a finishing step of adding gypsum to the clinker, grinding the mixture to finish the mixture into cement. In the firing step, the cement raw material is first preheated in a preheater, then calcined in a calciner, then fired in a kiln, and finally cooled in an air-cooled quench cooler (hereinafter referred to as "AQC"). In AQC, exhaust gas at 250-300 ℃ is generated in large amount. Conventionally, an exhaust heat recovery system is known that recovers exhaust heat by introducing exhaust gas generated in AQCs into a boiler and generates power by using the recovered heat.

For example, fig. 3 of patent document 1 discloses a waste heat recovery system including a high-temperature exhaust pipe connected to a high-temperature portion of an AQC and a low-temperature exhaust pipe connected to a low-temperature portion of the AQC. The high temperature exhaust pipe discharges exhaust gas having a relatively high temperature (e.g., 360 ℃ on average) in the AQC, and the low temperature exhaust pipe discharges exhaust gas having a relatively low temperature (e.g., 110 ℃ on average) in the AQC. Exhaust gas discharged from the AQCs through the high temperature exhaust pipe is directed to the boiler. In the boiler, superheated steam is generated due to heat of exhaust gas, and the superheated steam can be used in power generation of a steam turbine generator. The exhaust gas having been recovered in the boiler is merged with the exhaust gas discharged from the AQC through the low-temperature exhaust pipe, and then discharged to the atmosphere through the chimney via the dust collector.

Prior art documents

Patent document

Patent document 1: japanese patent No. 5897302

Disclosure of Invention

Problems to be solved by the invention

However, in general, clinker burned in the kiln falls from the kiln to the AQC due to its own weight. Therefore, the amount of clinker supplied to the AQCs varies, and as a result, the temperature of the exhaust gas generated in the AQCs fluctuates. Since such a variation in the temperature of the exhaust gas in the AQCs affects an increase or decrease in the heat recovered by the boiler, it is desirable to provide a system capable of efficiently recovering heat regardless of the variation in the temperature of the AQCs.

Accordingly, an object of the present invention is to provide a waste heat recovery system capable of efficiently recovering heat in an AQC boiler even when the temperature of exhaust gas in the AQC varies.

Means for solving the problems

In order to solve the above problems, an exhaust heat recovery system according to an aspect of the present invention is a system for recovering heat from exhaust gas generated by an AQC in a cement sintering facility including a kiln for sintering a cement raw material and the AQC as an air-cooled quench cooler for conveying and quenching a sinter charged from the kiln, the system including: a boiler recovering heat from exhaust gas generated by the AQCs; a 1 st exhaust pipe for guiding exhaust gas discharged from a predetermined high temperature part of the AQC to an inlet of the boiler; an exhaust device that exhausts the exhaust gas after heat is recovered by the boiler to the atmosphere; an exhaust pipe guiding exhaust gas discharged from an outlet of the boiler to the exhaust device; a 2 nd exhaust pipe configured to join exhaust gas discharged from a low-temperature portion of the AQC located downstream of the high-temperature portion in a direction in which the sinter is conveyed, with the exhaust pipe; a thermometer provided in the 1 st exhaust pipe; at least 1 flow rate adjustment device that adjusts a flow rate of the exhaust gas flowing through at least one of the 1 st exhaust pipe and the 2 nd exhaust pipe; and an instruction generating device that generates an instruction value for adjusting the at least 1 flow rate adjusting device so that a measurement value of the thermometer approaches a predetermined set value.

According to the above system, even when the temperature of the exhaust gas in the AQC varies, the temperature of the gas flowing into the boiler can be kept constant (i.e., at the set value) by adjusting the at least 1 flow rate adjusting device in accordance with the command value generated by the command generating device. This enables efficient heat recovery in the boiler even when the temperature of the exhaust gas in the AQC fluctuates.

The above system may be configured such that the command generating device generates the command value for decreasing at least the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe when the measured value is higher than the set value, and generates the command value for increasing at least the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe when the measured value is lower than the set value.

The system is configured such that, for example, the command generation device controls the at least 1 flow rate adjustment device based on the generated command value.

Alternatively, the system may further include: an operation device that receives an operation by an operator and generates an operation command; the control device is used for controlling the at least 1 flow regulating device according to the operation instruction; and an output device that outputs an operation instruction corresponding to the instruction value generated by the instruction generation device. According to this configuration, in the system in which at least 1 flow rate adjustment device is adjusted by the operation of the operator, 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 perform the operation for keeping the temperature of the gas flowing into the boiler constant on the operation device.

The system may further include: an introduction pipe connected to the 1 st exhaust pipe and introducing a low-temperature gas having a temperature lower than a temperature of the exhaust gas discharged from the high-temperature portion of the AQC into the 1 st exhaust pipe; and an opening/closing device provided in the introduction tube, wherein the command generation device generates a command value for maintaining a state in which the opening/closing device is closed when a measured value of the thermometer is equal to or less than a predetermined threshold value that is higher than the set value, and generates a command value for opening the opening/closing device when a temperature measured by the thermometer exceeds the threshold value. According to this configuration, the 3 rd damper is adjusted in accordance with the generated opening command, and thus, the gas having a temperature exceeding the allowable temperature can be prevented from flowing into the boiler.

In the above system, the thermometer may be a 1 st thermometer, a 2 nd thermometer may be provided upstream of the AQC in a direction in which the hot product is conveyed from the high temperature section, and the command generating device may predict the temperature of the exhaust gas at the inlet of the boiler after a predetermined time has elapsed from a current time, based on a measurement value of the 2 nd thermometer.

Effects of the invention

According to the present invention, it is possible to provide a waste heat recovery system capable of efficiently recovering heat in a boiler even when the temperature of exhaust gas in an AQC varies.

Drawings

Fig. 1 is a diagram showing a schematic configuration of a cement sintering facility including a waste heat recovery system according to an embodiment of the present invention.

Fig. 2 is a block diagram of a damper control in the waste heat recovery system shown in fig. 1.

Fig. 3 is a block diagram of damper control in the heat recovery system according to modification 1.

Fig. 4 is a block diagram of damper control in the exhaust heat recovery system according to modification 2.

Description of the reference symbols

1: cement sintering equipment; 2: a waste heat recovery system; 13: a converter; 14: an air-cooled quenching cooler; 30: AQC boilers (boilers); 43: 1 st exhaust pipe; 44: 2 nd discharge pipe (discharge pipe); 45: a 2 nd exhaust pipe; 46: an introducing pipe; 50: a control device (instruction generation device); 51: a thermometer (1 st thermometer); 52: 1 st damper (flow rate adjusting device); 53: the 2 nd damper (flow rate adjusting device); 54: the 3 rd damper (opening and closing device); 71: an instruction generating device; 72: an output device; 73: an operating device; 74: a control device; 100: a burner; 101: thermometer (2 nd thermometer).

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing a schematic configuration of a cement sintering facility 1 including a waste heat recovery system 2 according to the present embodiment.

(Cement sintering equipment)

As described above, the cement production process includes the raw material step, the calcination step, and the finishing step. The cement sintering facility 1 shown in fig. 1 is a facility which carries out a sintering step therein, and sinters clinker as an intermediate product from a powdery raw material (hereinafter referred to as "cement raw material") obtained by drying, pulverizing, blending limestone, clay, and the like in a raw material step. The cement sintering plant 1 comprises a preheater 11, a calciner 12, a converter 13 and an AQC 14.

The preheater 11 includes a plurality of stages of cyclones connected in series. In the preheater 11, the waste heat from the converter 13 moves from the lowermost cyclone to the uppermost cyclone in sequence, and the cement raw material moves from the uppermost cyclone to the lowermost cyclone in sequence. The cyclone separator of the lowermost stage of the preheater 11 is connected to the calciner 12.

In the calciner 12, the cement raw material discharged from the preheater 11 is calcined in an atmosphere of about 900 ℃. An exhaust duct 12a for the calciner for conveying the waste heat from the AQC14 to the calciner 12 and a fuel supply duct 12b for supplying fuel or the like to the calciner 12 are connected to the calciner 12. The outlet of the calciner 12 is connected to the inlet of the converter 13.

The converter 13 is a horizontally long cylindrical rotary kiln and is provided at a slight inclination descending from the raw material inlet to the raw material outlet. In the rotary kiln 13, the cement raw materials preheated and calcined in the preheater 11 and the calciner 12 are sintered by the waste heat of the AQC14 and the combustion gas of the burner 100. The outlet of the rotary kiln 13 is connected to the inlet 14a of the AQC 14.

In AQC14, the sinter at a high temperature (for example, about 1400 ℃) discharged from converter 13 is rapidly cooled. Specifically, the sinter dropped into AQC14 from the outlet of converter 13 is transported to outlet 14b by a conveyor belt, not shown, in AQC 14. The sinter is cooled by blowing cooling air from below the conveyor while being conveyed by the conveyor. The burned product, i.e., clinker cooled by AQC14 is discharged from outlet 14b, and then transported to a clinker silo by a clinker conveyor, not shown.

The cooling air blown out of the AQC14 to the hot sinter becomes high-temperature exhaust gas. The gas temperature in the AQCs 14 forms a distribution that becomes lower as it approaches the outlet 14b along the direction of conveyance of the sinter. For example, the gas temperature near the inlet 14a of AQC14 is about 1350 deg.C and the gas temperature near the outlet 14b of AQC14 is about 100 deg.C. However, as described above, the amount of clinker supplied to AQC14 fluctuates, and therefore the temperature of the exhaust gas in AQC14 fluctuates.

(waste heat recovery System)

The cement sintering facility 1 further includes a waste heat recovery system 2, and the waste heat recovery system 2 recovers heat from the exhaust gas of the high-temperature section 14c of the AQC14 and the exhaust gas generated by the preheater 11. The heat recovery system 2 includes an air-cooled quench 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 using exhaust gas generated in 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 31 b. In the boiler main body 31, a superheater 32, an evaporator 33, and a preheater (economizer) 34 as heat exchangers are provided in this order from the gas inlet 31a to the gas outlet 31 b. Further, a steam drum 35 is attached to the boiler main body 31.

A 1 st exhaust pipe 43 extending from the high temperature portion 14c of AQC14 is connected to the gas inlet 31a of the boiler main body 31. The high temperature section 14c of AQC14 is a section of AQC14 where the exhaust gas temperature is relatively high (e.g., about 350 ℃). For example, the average temperature of the high temperature section 14c of the AQC14 is within the allowable temperature range of the AQC boiler 30. By locating the upstream side end portion of the 1 st exhaust pipe 43 at the high temperature portion 14c of the AQC14, exhaust gas having a relatively high temperature is guided from the AQC14 to the AQC boiler 30 through the 1 st exhaust line 43 and is used as a heating medium of the AQC boiler 30.

Further, the exhaust gas pipe 12a for the calciner described above is connected to the AQC 14. The extraction pipe 12a for the calciner is connected to the AQC14 on the upstream side in the sinter conveyance direction from the connection position of the 1 st exhaust pipe 43 and the AQC 14. Therefore, the exhaust gas having a temperature higher than that of the exhaust gas discharged from the 1 st exhaust pipe 43 (for example, about 600 ℃) is extracted from the exhaust pipe 12a for the calciner.

Further, in the AQC14, a thermometer 101 (corresponding to the "2 nd thermometer" in the present invention) is provided on the upstream side in the sintered product conveying direction than the high temperature section 14 c. The measurement value of the thermometer 101 is sent to the control device 50.

A 2 nd discharge pipe 44 (corresponding to "discharge pipe" of the present invention) is connected to the gas outlet 31b of the boiler main body 31. In the 2 nd exhaust pipe 44, a dust collector 36, an exhaust fan 37, and a stack 38 (corresponding to the "exhaust device" of the present invention) are provided in this order from the upstream to the downstream of the exhaust flow. The exhaust gas heat-exchanged in the AQC boiler 30 passes through the dust collector 36 and is discharged to the atmosphere through the stack 38.

Exhaust 2-th pipe 45 extends from low temperature portion 14d of AQC 14. The low temperature part 14d of AQC14 is a part of AQC14 where the exhaust gas temperature is relatively low (for example, about 150 ℃), and is located on the downstream side in the sinter conveying direction of the high temperature part 14c in AQC 14. When the upstream end portion of the 2 nd exhaust pipe 45 is positioned at the low temperature portion 14d of the AQC14, exhaust gas having a relatively low temperature is discharged from the AQC14 through the 2 nd exhaust pipe 45. The downstream side end of the 2 nd exhaust pipe 45 is connected between the AQC boiler 30 and the dust collector 36 in the 2 nd exhaust pipe 44. That is, the exhaust gas discharged from the low temperature part 14d of the AQC14 joins the exhaust gas discharged from the outlet 31b of the AQC boiler 30 through the 2 nd exhaust pipe 45, and then passes through the dust collector 36 and is discharged to the atmosphere from the stack 38.

A thermometer 51 (corresponding to the "thermometer" and the "1 st thermometer" of the present invention) is provided to the 1 st exhaust pipe 43, and the thermometer 51 measures the temperature of the exhaust gas introduced into the AQC boiler 30. Further, a 1 st damper 52 is provided in a portion of the 1 st exhaust pipe 43 on the upstream side of the thermometer 51. In addition, the 2 nd exhaust pipe 45 is provided with a 2 nd damper 53. The introduction pipe 46 is connected between the 1 st damper 52 and the thermometer 51 in the 1 st exhaust pipe 43. The 3 rd damper 54 is provided in the introduction pipe 46. In the present embodiment, the 1 st damper 52, the 2 nd damper 53, and the 3 rd damper 54 are controlled by the control device 50 to adjust the opening degrees thereof. The control method of the control device 50 will be described in detail later.

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

The control device 50 controls the 1 st damper 52, the 2 nd damper 53, and the 3 rd damper 54 according to the temperature measured by the thermometer 51. Fig. 2 shows a block diagram of a damper control in the waste heat recovery system 2. The control device 50 includes a processor, a volatile memory, and a non-volatile memory. The processor is configured by a CPU, an MPU, a GPU, and the like, and reads and executes various programs stored in the memory, thereby realizing control corresponding to a control target and various functional units described later.

Fig. 2 shows a functional structure of the control device 50. The control device 50 includes an opening command generating 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 constituted by one unit, but may be constituted by a plurality of units. The opening command generating unit 50a generates opening command values as opening information of the 1 st damper 52, the 2 nd damper 53, and the 3 rd damper 54 based on the measurement values of the thermometer 51. The damper control unit 50b controls the 1 st damper 52, the 2 nd damper 53, and the 3 rd damper 54 in accordance with the opening command generated by the opening command generation unit 50 a.

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

Assuming that the opening degrees of the 1 st damper 52 and the 2 nd damper 53 are constant, the temperature of the exhaust gas guided to the AQC boiler 30 through the 1 st exhaust pipe 43 also fluctuates depending on the temperature fluctuation of the exhaust gas in the AQC 14. In the present embodiment, the controller 50 controls at least one of the 1 st damper 52 and the 2 nd damper 53 to maintain the temperature of the exhaust gas introduced into the AQC boiler 30 at a predetermined temperature.

Specifically, the opening command generating unit 50a generates a command value (opening command value) for adjusting at least one of the 1 st damper 52 and the 2 nd damper 53 so that the measurement value T of the thermometer 51 approaches a predetermined set value T1. That is, the control device 50 functions as the "command generating device" of the present invention. Here, the predetermined set value T1 is set to a value (e.g., 360 ℃) that is equal to or lower than the allowable upper limit (e.g., 400 ℃) of the AQC boiler 30 and as close to the allowable upper limit as possible in order to recover the heat of the exhaust gas in the AQC14 as possible.

Next, an example of damper control by the control device 50 will be described. In the example described here, an example will be described in which the controller 50 adjusts only the opening degree of the 2 nd damper 53 out of the 1 st damper 52 and the 2 nd damper 53. That is, in the example described here, the opening degree of the 1 st damper 52 is fixed to a predetermined opening degree. In this example, the 2 nd damper 53 functions as a flow rate adjustment device that adjusts the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe 45, and corresponds to "at least 1 flow rate adjustment device" of the present invention.

The damper control unit 50b controls the 1 st damper 52 such that the 1 st damper 52 is fully closed when the operation of the AQC boiler 30 is stopped, and the opening degree of the 1 st damper 52 is a predetermined opening degree (for example, fully opened) when the AQC boiler 30 is operated. When the measured value T of the thermometer 51 is higher than a predetermined set value T1 during the operation of the AQC boiler 30, the opening command generating unit 50a generates a command value (opening command) for decreasing the opening of the 2 nd damper 53. The damper control unit 50b adjusts the opening degree of the 2 nd damper 53 in accordance with the generated command value. As the opening of the 2 nd damper 53 decreases, the amount of lower temperature exhaust gas discharged from the AQC14 through the 2 nd exhaust pipe 45 decreases. Thus, the temperature of the exhaust gas discharged from the AQC14 through the 1 st exhaust pipe 43 is lowered, and the measurement value T of the thermometer 51 can be brought close to the predetermined set value T1.

When the measured value T of the thermometer 51 is lower than a predetermined set value T1, the opening command generating unit 50a generates a command value (opening command) for increasing the opening of the 2 nd damper 53. The damper control unit 50b adjusts the opening degree of the 2 nd damper 53 in accordance with the generated command value. As the opening of the 2 nd damper 53 increases, the amount of lower temperature exhaust gas discharged from the AQC14 through the 2 nd exhaust pipe 45 increases. Thus, the temperature of the exhaust gas discharged from the AQC14 through the 1 st exhaust pipe 43 increases, and the measurement value T of the thermometer 51 can be brought close to the predetermined set value T1.

However, the damper control described above is merely an example. For example, the controller 50 may adjust the opening degrees of both the 1 st damper 52 and the 2 nd damper 53. In this case, the 1 st damper 52 functions as a flow rate adjustment device that adjusts the flow rate of the exhaust gas flowing through the 1 st exhaust pipe 43, and the 2 nd damper 53 functions as a flow rate adjustment device that adjusts the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe 45. Also, the 1 st damper 52 and the 2 nd damper 53 correspond to "at least 1 flow rate adjusting means" of the present invention.

When the controller 50 adjusts the opening degrees of both the 1 st damper 52 and the 2 nd damper 53, the opening degree command generating unit 50a generates a command value (opening degree command) for decreasing the opening degree of the 2 nd damper 53 and increasing the opening degree of the 1 st damper 52 when the measured value T of the thermometer 51 is higher than a predetermined set value T1. The damper control unit 50b adjusts the opening degrees of the 1 st damper 52 and the 2 nd damper 53 in accordance with the generated command value. When the measured value T of the thermometer 51 is lower than a predetermined set value T1, the opening command generating unit 50a generates a command value (opening command) for increasing the opening of the 2 nd damper 53 and decreasing the opening of the 1 st damper 52. The damper control unit 50b adjusts the opening degrees of the 1 st damper 52 and the 2 nd damper 53 in accordance with the generated command value.

Alternatively, the opening degree of the 2 nd damper 53 may be fixed to a predetermined opening degree, and the controller 50 may adjust only the opening degree of the 1 st damper 52 out of the 1 st damper 52 and the 2 nd damper 53. In this case, the 1 st damper 52 functions as a flow rate adjustment device that adjusts the flow rate of the exhaust gas flowing through the 1 st exhaust pipe 43. Also, the 1 st damper 52 corresponds to "at least 1 flow rate adjusting means" of the present invention.

When the controller 50 adjusts only the opening degree of the 1 st damper 52, the opening degree command generating unit 50a generates a command value (opening degree command) for increasing the opening degree of the 1 st damper 52 when the measured value T of the thermometer 51 is higher than the predetermined set value T1. The damper control unit 50b adjusts the opening degree of the 1 st damper 52 based on the generated command value (opening degree command). When the measured value T of the thermometer 51 is lower than a predetermined set value T1, the opening command generating unit 50a generates a command value (opening command) for decreasing the opening of the 1 st damper 52. The damper control unit 50b adjusts the opening degree of the 1 st damper 52 based on the generated command value.

Further, the control device 50 controls the 3 rd damper 54 provided in the introduction pipe 46. The introduction pipe 46 is used to introduce a low-temperature gas having a temperature lower than that of the exhaust gas discharged from the high-temperature portion 14c in the AQC14 into the 1 st exhaust pipe 43. The low-temperature gas introduced into the 1 st exhaust pipe 43 through the introduction pipe 46 is, for example, outside air.

The 3 rd damper 54 functions as an opening/closing device for opening/closing the introduction pipe 46. When the AQC boiler 30 is operating, the 3 rd damper 54 is normally closed. When the opening degree of the 2 nd damper 53 is adjusted, but the temperature of the exhaust gas introduced into the AQC boiler 30 exceeds the allowable upper limit value of the AQC boiler 30, the 3 rd damper 54 is opened. Specifically, when the measured value T of the thermometer 51 is equal to or less than a predetermined threshold value T2 which is higher than the set value T1, the controller 50 maintains the state in which the 3 rd damper 54 is closed. That is, the opening command generating unit 50a generates a command value (opening command) for fully closing the 3 rd damper 54 when the measurement value T of the thermometer 51 is equal to or less than the threshold value T2, and the damper control unit 50b sets the 3 rd damper 54 in the closed state based on the generated command value. Here, the predetermined threshold T2 is set between the allowable upper limit and the set value T1 (e.g., 390 ℃) so that the temperature of the exhaust gas flowing into the boiler main body 31 does not exceed the allowable upper limit (e.g., 400 ℃) of the AQC boiler 30. However, the predetermined threshold T2 may be set to the allowable upper limit value of the AQC boiler 30.

In addition, when the measured value T of the thermometer 51 exceeds the threshold value T2, the control device 50 opens the 3 rd damper 54. That is, the opening command generating unit 50a generates a command value (opening command) for fully opening or opening the 3 rd damper 54 to a predetermined opening degree when the measured value T of the thermometer 51 exceeds the threshold value T2, and the damper control unit 50b opens the 3 rd damper 54 based on the generated command value. For example, the opening command generating unit 50a may generate a command value for opening the 3 rd 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 waste heat recovery system 2 of the present embodiment, the opening command generating unit 50a generates a command value (opening command value) for adjusting at least one of the 1 st damper 52 and the 2 nd damper 53 so that the measurement value T of the thermometer 51 approaches the predetermined set value T1. The damper control unit 50b adjusts at least one of the 1 st damper 52 and the 2 nd damper 53 in accordance with the generated command value. This can keep the temperature of the gas flowing into the AQC boiler 30 constant (i.e., at a set value). This enables efficient heat recovery in the AQC boiler 30 even when the temperature of the exhaust gas in the AQC14 varies.

In the present embodiment, the controller 50 maintains the state of closing the 3 rd damper 54 when the measured value T of the thermometer 51 is equal to or less than the predetermined threshold value T2 which is higher than the set value T1, and opens the 3 rd damper 54 when the measured value T of the thermometer 51 exceeds the threshold value T2. This can prevent gas having a temperature exceeding the allowable temperature from flowing into the AQC boiler 30.

(modification 1)

In the above embodiment, the case where the control device 50 controls at least one of the 1 st damper 52 and the 2 nd damper 53 so that the measured value T of the thermometer 51 approaches the predetermined set value T1, that is, performs the so-called feedback control, has been described. In addition to performing the feedback control, the controller 50 may perform feed-forward control for controlling at least one of the 1 st damper 52 and the 2 nd damper 53 before the temperature change of the measurement value T of the thermometer 51.

Fig. 3 is a block diagram of damper control in the heat recovery system according to modification 1. The control device 50 includes a temperature predicting unit 50c in addition to the opening degree command generating unit 50a and the damper control unit 50 b. The temperature predicting unit 50c is configured by combining hardware such as the CPU included in the control device 50 and software stored in the ROM or the like.

The temperature predicting section 50c predicts the temperature of the exhaust gas at the inlet 31a of the AQC boiler 30 after a predetermined time (for example, after 10 minutes) has elapsed from the current time, based on the measurement value of the thermometer 101 provided at the AQC14 on the upstream side in the sinter conveying direction than the high temperature section 14 c. The prediction result can be used for correcting the command value generated by the opening command generating unit 50 a.

The opening command generating unit 50a corrects a command value for bringing the measured value T of the thermometer 51 at the present time closer to a predetermined set value T1, based on the prediction result of the temperature predicting unit 50 c. This correction is for suppressing a deviation of the measured value T of the thermometer 51 from the predetermined set value T1 that may occur from the present time.

Specifically, when the temperature predicted by the temperature predicting unit 50c is higher than, for example, the predetermined set value T1, it is predicted that the measured value T of the thermometer 51 will be shifted to be higher than the predetermined set value T1 thereafter. Therefore, the opening command generating part 50a corrects the generated command value so that the temperature of the exhaust gas at the inlet 31a of the AQC boiler 30 is decreased, in other words, so that the opening of the 2 nd damper 53 is decreased and/or the opening of the 1 st damper 52 is increased. When the temperature predicted by the temperature predicting unit 50c is lower than, for example, the predetermined set value T1, it is predicted that the measured value T of the thermometer 51 will be shifted in a direction lower than the predetermined set value T1 thereafter. Therefore, the opening command generating unit 50a corrects the generated command value so that the temperature of the exhaust gas at the inlet 31a of the AQC boiler 30 is increased, in other words, so that the opening of the 2 nd damper 53 is increased and/or the opening of the 1 st damper 52 is decreased.

According to this modification 1, even with a sudden temperature change of the exhaust gas in the AQC14, it is possible to quickly suppress the deviation of the measured value T of the thermometer 51 from the predetermined set value T1.

(modification 2)

In the above embodiment, the control device 50 generates the command value for adjusting at least one of the 1 st damper 52 and the 2 nd damper 53 so that the measured value T of the thermometer 51 approaches the predetermined set value T1, and controls at least one of the 1 st damper 52 and the 2 nd damper 53 based on the command value, but the present invention is not limited to this. For example, the waste heat recovery system of the present invention may be configured such that the opening degree of at least one of the 1 st damper 52 and the 2 nd damper 53 is adjusted by manual operation of an operator.

Fig. 4 is a block diagram of damper control in the exhaust heat recovery system according to modification 2. In this waste heat recovery system, the opening degree of at least one of the 1 st damper 52 and the 2 nd damper 53 is adjusted by a manual operation of an operator. The waste heat recovery system includes an instruction generating device 71, an output device 72, an operating device 73, and a control device 74. The command generating device 71 generates a command value for adjusting at least one of the 1 st damper 52 and the 2 nd damper 53 so that the measured value T of the thermometer 51 approaches a predetermined set value T1. The output device 72 outputs an operation instruction corresponding to the instruction value generated by the instruction generating device 71. The operation device 73 receives an operation by an operator and generates an operation command. The controller 74 controls at least one of the 1 st damper 52 and the 2 nd damper 53 in accordance with an operation command generated by the operation device 73.

The output device 72 and the operation device 73 are disposed in the same space (for example, an operation chamber of the cement sintering apparatus 1) 70 so that an operator can operate the operation device 73 based on the output of the output device 72. The output device 72 may be of any output type as long as it can transmit an instruction for the operation of the operation device 73 to the operator, and may be, for example, a display capable of outputting an operation instruction screen, or a speaker capable of outputting an operation instruction by voice. For example, the output device 72 and the operation device 73 may be integrally configured, and may be a touch panel, for example. The command generating device 71 may be integrated with the output device 72.

According to the waste heat recovery system of 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 perform the operation of the operation device 73 for maintaining the temperature of the gas flowing into the AQC boiler 30 to be constant. Therefore, in the modification 2, as in the above embodiment, heat can be efficiently recovered in the AQC boiler 30.

The present invention is not limited to the above-described embodiments and modifications, and various modifications can be made without departing from the spirit of the present 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 may predict the temperature of the exhaust gas at the inlet 31a of the AQC boiler 30 after a predetermined time (for example, after 10 minutes) has elapsed from the current time, based on the measured value of the thermometer 101 provided at the upstream side of the high temperature section 14c in the sinter conveying direction in the AQC14, and may correct the command value for bringing the measured value T of the thermometer 51 at the current time close to the predetermined set value T1 based on the prediction result.

In the above-described embodiment, the 1 st damper 52 and the 2 nd damper 53 are described as the flow rate adjusting device for adjusting the flow rate of the exhaust gas flowing through the 1 st exhaust pipe 43 and the 2 nd exhaust pipe 45, respectively, and the 3 rd damper 54 is described as the opening/closing device for opening/closing the introduction pipe 46, but the "flow rate adjusting device" and the "opening/closing device" in the present invention are not limited to the dampers. For example, as the "flow rate adjusting device" and the "opening/closing device" in the present invention, a known flow rate adjusting device such as a valve or a blower may be used instead of the damper.