CN111747667B - Waste heat recovery system - Google Patents
Waste heat recovery system Download PDFInfo
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- CN111747667B CN111747667B CN201910250059.9A CN201910250059A CN111747667B CN 111747667 B CN111747667 B CN 111747667B CN 201910250059 A CN201910250059 A CN 201910250059A CN 111747667 B CN111747667 B CN 111747667B
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- exhaust gas
- thermometer
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- boiler
- temperature
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/36—Manufacture of hydraulic cements in general
- C04B7/43—Heat treatment, e.g. precalcining, burning, melting; Cooling
- C04B7/47—Cooling ; Waste heat management
- C04B7/475—Cooling ; Waste heat management using the waste heat, e.g. of the cooled clinker, in an other way than by simple heat exchange in the cement production line, e.g. for generating steam
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/36—Manufacture of hydraulic cements in general
- C04B7/43—Heat treatment, e.g. precalcining, burning, melting; Cooling
- C04B7/44—Burning; Melting
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/36—Manufacture of hydraulic cements in general
- C04B7/43—Heat treatment, e.g. precalcining, burning, melting; Cooling
- C04B7/47—Cooling ; Waste heat management
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Abstract
The invention provides a waste heat recovery system. Even when the exhaust temperature in the AQC fluctuates, the AQC boiler can be used to efficiently recover heat. The waste heat recovery system has: a boiler for recovering heat from exhaust gas generated by the AQC; a 1 st exhaust pipe for guiding the exhaust gas discharged from the predetermined high temperature part of the AQC to the boiler inlet; an exhaust device that exhausts the exhaust gas after heat is recovered by the boiler to the atmosphere; a discharge pipe guiding exhaust gas discharged from the boiler outlet to a discharge device; a 2 nd exhaust pipe for merging exhaust gas discharged from the low-temperature part of the AQC located downstream of the high-temperature part in the direction of conveying the sintered product with the exhaust pipe; the thermometer is arranged on the 1 st exhaust pipe; at least 1 flow rate adjusting means for adjusting the flow rate of exhaust gas flowing through at least one of the 1 st exhaust pipe and the 2 nd exhaust pipe; and a command generating device for generating command values for adjusting at least 1 flow rate adjusting device in such a manner that the measured value of the thermometer approaches a prescribed set value.
Description
Technical Field
The present invention relates to a waste heat recovery system for recovering heat from exhaust gas of cement manufacturing process.
Background
The cement manufacturing process is generally 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 a raw material; and a finishing step of adding gypsum to the clinker, pulverizing, and finishing the clinker to obtain 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 AQCs, exhaust gas is produced in large amounts at 250-300 ℃. Conventionally, there is known a waste heat recovery system that introduces waste gas generated in AQCs into a boiler to recover waste heat and uses the recovered heat to generate power.
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 AQC and a low-temperature exhaust pipe connected to a low-temperature portion of AQC. The high temperature exhaust pipe exhausts exhaust gas having a higher temperature (e.g., an average of 360 ℃) in the AQCs, and the low temperature exhaust pipe exhausts exhaust gas having a lower temperature (e.g., an average of 110 ℃) in the AQCs. The 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, which has recovered heat in the boiler, merges with the exhaust gas discharged from the AQCs through the low-temperature exhaust pipe, and is discharged from the stack to the atmosphere through the dust collector.
Prior art literature
Patent literature
Patent document 1: japanese patent No. 5897302
Disclosure of Invention
Problems to be solved by the invention
However, in general, clinker burned in a kiln is dropped from the kiln to AQC due to its own weight. Accordingly, the clinker supply amount to the AQCs varies widely, and as a result, the temperature of the exhaust gas generated in the AQCs fluctuates. Such a temperature fluctuation of exhaust gas in AQCs affects increase or decrease of heat recovered in a boiler, and therefore, it is desired to propose a system capable of efficiently recovering heat regardless of the temperature fluctuation in 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 fluctuates.
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 AQCs in a cement sintering plant including a kiln for sintering cement raw materials and an AQCs which is an air-cooled quenching cooler for conveying and quenching a sinter fed from the kiln, the system comprising: a boiler that recovers heat from exhaust gas generated by the AQCs; a 1 st exhaust pipe for guiding the exhaust gas discharged from the predetermined high temperature part of the AQC to the inlet of the boiler; an exhaust device that exhausts exhaust gas after heat recovery by the boiler to the atmosphere; a discharge pipe guiding exhaust gas discharged from an outlet of the boiler toward the discharge apparatus; a 2 nd exhaust pipe that merges with the exhaust pipe an exhaust gas discharged from the low-temperature portion of the AQC located downstream of the high-temperature portion in a direction of conveying the sintered product; a thermometer provided in the 1 st exhaust pipe; at least 1 flow rate adjustment device that adjusts a flow rate of 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 the measured value of the thermometer approaches a prescribed set value.
According to the above system, even when the temperature of the exhaust gas in the AQC fluctuates, the at least 1 flow rate adjustment device is adjusted in accordance with the command value generated by the command generation device, so that the temperature of the gas flowing into the boiler can be kept constant (i.e., kept at the set value). Thus, even when the temperature of the exhaust gas in the AQC fluctuates, heat can be efficiently recovered in the boiler.
In the above system, the command generating means may be configured to generate the command value that decreases 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 to generate the command value that increases 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 above system is configured such that, for example, the command generating means controls the at least 1 flow rate adjusting means based on the generated command value.
Alternatively, the system is configured to further include: an operation device that receives an operation by an operator and generates an operation instruction; control means for controlling the at least 1 flow rate adjustment means in accordance with the operation instruction; and an output device that outputs an operation instruction corresponding to the instruction value generated by the instruction generating device. According to this configuration, in a system in which at least 1 flow rate adjustment device is adjusted by an operation of an operator, an operation instruction corresponding to the instruction value generated by the instruction generation device is output to the output device. Therefore, the operator can be guided to perform an operation for maintaining the temperature of the gas flowing into the boiler to be constant with respect to the operation device.
The system may further include: an introduction pipe connected to the 1 st exhaust pipe, for introducing a low-temperature gas having a temperature lower than that of the exhaust gas discharged from the high-temperature part of the AQC into the 1 st exhaust pipe; and an opening/closing device provided in the introduction pipe, wherein the command generating device generates a command value for maintaining a 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 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 the gas 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 on an upstream side of the AQC in a direction of conveying the sinter from the high temperature part, and the instruction generator may predict a temperature of the exhaust gas at the inlet of the boiler after a predetermined time from a current time based on a measured value of the 2 nd thermometer.
Effects of the invention
According to the present invention, it is possible to provide a heat recovery system capable of efficiently recovering heat in a boiler even when the temperature of exhaust gas in AQCs fluctuates.
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 damper control in the waste heat recovery system shown in FIG. 1.
Fig. 3 is a block diagram of damper control in the waste heat recovery system of modification 1.
Fig. 4 is a block diagram of damper control in the waste heat recovery system of modification 2.
Description of the reference numerals
1: cement sintering equipment; 2: a waste heat recovery system; 13: a converter; 14: an air-cooled quenching cooler; 30: AQC boilers (boilers); 43: a 1 st exhaust pipe; 44: a 2 nd discharge pipe (discharge pipe); 45: a 2 nd exhaust pipe; 46: an ingress pipe; 50: control means (instruction generation means); 51: thermometer (1 st thermometer); 52: 1 st damper (flow regulator); 53: a 2 nd damper (flow rate adjusting device); 54: 3 rd damper (opening/closing device); 71: instruction generating means; 72: an output device; 73: an operating device; 74: a control device; 100: a burner; 101: thermometer (thermometer 2).
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 manufacturing process includes the raw material process, the calcination process, and the finishing process. The cement sintering equipment 1 shown in fig. 1 performs a sintering process in which clinker as an intermediate product is sintered from a powder raw material (hereinafter, referred to as "cement raw material") obtained by drying, pulverizing, blending limestone, clay, and the like in a raw material process. The cement sintering plant 1 comprises a preheater 11, a calciner 12, a rotary kiln 13 and an AQC14.
The preheater 11 comprises a plurality of cyclone separators connected in series. In the preheater 11, the waste heat from the converter 13 moves from the cyclone at the lowest stage to the cyclone at the highest stage in sequence, and the cement raw material moves from the cyclone at the highest stage to the cyclone at the lowest stage in sequence. The lowest cyclone of the preheater 11 is connected to the calciner 12.
In the calciner 12, the cement raw material from the preheater 11 is calcined under an atmosphere of about 900 ℃. The calciner 12 is connected to a calciner exhaust pipe 12a for supplying waste heat from the AQC14 to the calciner 12 and a fuel supply pipe 12b for supplying fuel or the like to the calciner 12. The outlet of the calciner 12 is connected to the inlet of the rotary kiln 13.
The rotary kiln 13 is a horizontally long cylindrical rotary kiln, and is provided with a slope slightly decreasing from a raw material inlet to a 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 using 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 AQC14.
In AQC14, the high temperature (e.g., about 1400 ℃) sinter exiting from converter 13 is rapidly cooled. Specifically, the sinter dropped from the outlet of the converter 13 into the AQC14 is conveyed to the outlet 14b by a conveyor belt, not shown, in the AQC14. During the period of conveying the sintered product by the conveyor belt, cooling air is blown from below the conveyor belt to cool the sintered product. After the burned product cooled by the AQCs 14, i.e., clinker comes out of the outlet 14b, the burned product is transported to a clinker silo by a clinker conveyor not shown.
The cooling air blown out of the high-temperature sintered product in the AQC14 becomes high-temperature exhaust gas. The gas temperature in the AQCs 14 is distributed so as to become lower as the temperature gets closer to the outlet 14b in the conveying direction of the sinter. For example, the gas temperature near the inlet 14a of the AQC14 is about 1350 ℃ and the gas temperature near the outlet 14b of the AQC14 is about 100 ℃. However, as described above, since the clinker supply amount to the AQCs 14 varies in a wide range, the temperature of the exhaust gas in the AQCs 14 varies.
(waste heat recovery System)
The cement sintering plant 1 is further provided with a waste heat recovery system 2, and the waste heat recovery system 2 recovers heat from the exhaust gas of the high temperature portion 14c of the AQC14 and the exhaust gas generated by the preheater 11. The waste heat recovery system 2 includes an air-cooled quench cooler boiler (hereinafter, referred to as an 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. A superheater 32, an evaporator 33, and a preheater (economizer) 34, which are heat exchangers, are provided in this order from a gas inlet 31a to a gas outlet 31b in the boiler body 31. A steam drum 35 is attached to the boiler body 31.
A 1 st exhaust pipe 43 extending from the high temperature portion 14c of the AQC14 is connected to the gas inlet 31a of the boiler body 31. The high temperature portion 14c of the AQC14 is a portion of the AQC14 where the exhaust temperature is relatively high (e.g., about 350 ℃). For example, the average temperature of the high temperature portion 14c of the AQC14 is within the allowable temperature range of the AQC boiler 30. By positioning the upstream end 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 used as a heating medium for the AQC boiler 30.
The exhaust pipe 12a for the calciner is connected to the AQC14. The calciner exhaust pipe 12a is connected to the AQC14 at a position upstream of the connection position of the 1 st exhaust pipe 43 and the AQC14 in the conveying direction of the sinter. Therefore, 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 calciner exhaust pipe 12a.
Further, a thermometer 101 (corresponding to "the 2 nd thermometer" of the present invention) is provided on the AQC14 upstream side in the conveying direction of the sintered product than the high temperature portion 14 c. The measured value of the thermometer 101 is sent to the control device 50.
A 2 nd discharge pipe 44 (corresponding to the "discharge pipe" of the present invention) is connected to the gas outlet 31b of the boiler body 31. In the 2 nd discharge pipe 44, a dust collector 36, an exhaust fan 37, and a stack 38 (corresponding to the "discharge apparatus" of the present invention) are provided in this order from the upstream to the downstream of the exhaust gas flow. The exhaust gas after heat exchange in the AQC boiler 30 is discharged to the atmosphere from the stack 38 through the dust collector 36.
The 2 nd exhaust pipe 45 extends from the low temperature portion 14d of the AQC14. The low temperature portion 14d of the AQC14 is a portion of the AQC14 where the exhaust gas temperature is low (for example, about 150 ℃) and is located at a position of the AQC14 downstream in the sinter conveying direction than the high temperature portion 14 c. By positioning the upstream end of the 2 nd exhaust pipe 45 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 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 portion 14d of the AQC14 is merged with the exhaust gas discharged from the outlet 31b of the AQC boiler 30 through the 2 nd exhaust pipe 45, and then discharged to the atmosphere from the stack 38 through the dust collector 36.
A thermometer 51 (corresponding to the "thermometer" and "1 st thermometer" of the present invention) is provided on 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 the 1 st exhaust pipe 43 upstream of the thermometer 51. Further, the 2 nd damper 53 is provided in the 2 nd exhaust pipe 45. Further, an introduction pipe 46 is connected between a 1 st damper 52 and a 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 so as 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 damper control in the waste heat recovery system 2. The control device 50 includes a processor, volatile memory, and nonvolatile memory. The processor is configured by CPU, MPU, GPU and the like, 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 the 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 and the like. The control device 50 may be constituted not by one unit but 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 measured 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 based on the opening command generated by the opening command generation unit 50 a.
The damper control by the control device 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 AQC14. In the present embodiment, the control device 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 measured value T of the thermometer 51 approaches the predetermined set value T1. That is, the control device 50 functions as "command generating means" of the present invention. Here, the predetermined set value T1 is set to a value (for example, 360 ℃) which is equal to or less than the allowable upper limit value (for example, 400 ℃) of the AQC boiler 30 and as close to the allowable upper limit value as possible so that the heat of the exhaust gas in the AQC14 can be recovered as much as possible.
An example of damper control by the control device 50 will be described below. In the example described here, the control device 50 is described as an example of adjusting 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 in the 2 nd exhaust pipe 45, corresponding 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 AQC boiler 30 is stopped, and the 1 st damper 52 is opened by 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 the predetermined set value T1 during 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 based on the generated command value. As the opening degree of the 2 nd damper 53 decreases, the amount of exhaust gas discharged from the AQC14 through the 2 nd exhaust pipe 45 decreases. Accordingly, the temperature of the exhaust gas discharged from the AQC14 through the 1 st exhaust pipe 43 is reduced, and the measured value T of the thermometer 51 can be made to approach the predetermined set value T1.
When the measured value T of the thermometer 51 is lower than the predetermined set value T1, the opening command generation 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 based on the generated command value. As the opening degree of the 2 nd damper 53 increases, the amount of exhaust gas discharged from the AQC14 through the 2 nd exhaust pipe 45 increases. As a result, the temperature of the exhaust gas discharged from the AQC14 through the 1 st exhaust pipe 43 increases, and the measured value T of the thermometer 51 can be made closer to the predetermined set value T1.
However, the damper control described above is only one example. For example, the control device 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 for adjusting 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 for adjusting the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe 45. Further, 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 control device 50 adjusts the opening degrees of both the 1 st damper 52 and the 2 nd damper 53, the opening degree command generation 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 the 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 according to the generated command value. When the measured value T of the thermometer 51 is lower than the predetermined set value T1, the opening command generation 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 according to the generated command value.
Alternatively, the opening degree of the 2 nd damper 53 may be fixed to a predetermined opening degree, and the control device 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. Further, the 1 st damper 52 corresponds to "at least 1 flow rate adjusting means" of the present invention.
When the control device 50 adjusts only the opening degree of the 1 st damper 52, the opening degree command generation 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 the predetermined set value T1, the opening command generation 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.
The control device 50 controls the 3 rd damper 54 provided in the introduction pipe 46. The introduction pipe 46 is for introducing 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. In addition, although the opening degree of the 2 nd damper 53 is adjusted, the 3 rd damper 54 is opened when the exhaust gas temperature introduced into the AQC boiler 30 exceeds the allowable upper limit value of the AQC boiler 30. Specifically, when the measured value T of the thermometer 51 is equal to or smaller than the predetermined threshold T2 higher than the set value T1, the control device 50 maintains the state of closing the 3 rd damper 54. That is, when the measured value T of the thermometer 51 is equal to or less than the threshold value T2, the opening command generating unit 50a generates a command value (opening command) for fully closing the 3 rd damper 54, and the damper control unit 50b sets the 3 rd damper 54 to the closed state based on the generated command value. Here, for example, the predetermined threshold T2 is set between the allowable upper limit value and the set value T1 (e.g., 390 ℃) so that the temperature of the exhaust gas flowing into the boiler body 31 does not exceed the allowable upper limit value (e.g., 400 ℃) of the AQC boiler 30. However, the predetermined threshold T2 may be set as the allowable upper limit value of the AQC boiler 30.
In addition, when the measured value T of the thermometer 51 exceeds the threshold T2, the control device 50 opens the 3 rd damper 54. That is, when the measured value T of the thermometer 51 exceeds the threshold value T2, 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, and the damper control unit 50b opens the 3 rd damper 54 based on the generated command value. For example, the opening degree command generating unit 50a may generate a command value for opening the 3 rd damper 54 to an opening degree 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 measured 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 according to the generated command value. Thereby, the temperature of the gas flowing into the AQC boiler 30 can be kept constant (i.e., kept at the set value). Accordingly, even when the temperature of the exhaust gas in the AQC14 fluctuates, heat can be efficiently recovered in the AQC boiler 30.
In the present embodiment, when the measured value T of the thermometer 51 is equal to or smaller than the predetermined threshold T2 higher than the set value T1, the control device 50 maintains the state of closing the 3 rd damper 54, and when the measured value T of the thermometer 51 exceeds the threshold T2, opens the 3 rd damper 54. This prevents gas exceeding the allowable temperature from flowing into the AQC boiler 30.
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, that is, performs so-called feedback control so that the measured value T of the thermometer 51 approaches the predetermined set value T1 has been described. In addition to performing such feedback control, the control device 50 may perform feedforward control for controlling at least one of the 1 st damper 52 and the 2 nd damper 53 before the temperature of the measured value T of the thermometer 51 changes.
Fig. 3 is a block diagram of damper control in the waste heat recovery system of modification 1. The control device 50 includes a temperature prediction unit 50c in addition to the opening command generation unit 50a and the damper control unit 50 b. The temperature predicting unit 50c is constructed by combining hardware such as the CPU and the like provided in the control device 50 with software stored in the ROM and the like.
The temperature predicting unit 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) from the current time based on the measured value of the thermometer 101 provided in the AQC14 on the upstream side in the conveying direction of the sintered product than the high temperature unit 14 c. The prediction result may be used for correcting the command value generated by the opening command generating unit 50 a.
The opening command generating unit 50a corrects the command value for bringing the measured value T of the thermometer 51 at the current time to the predetermined set value T1 based on the prediction result of the temperature predicting unit 50c. This correction is a correction for suppressing the deviation of the measured value T of the thermometer 51 from the predetermined set value T1, which may occur from the current time.
Specifically, when the temperature predicted by the temperature predicting unit 50c is higher than the predetermined set value T1, for example, it is predicted that the measured value T of the thermometer 51 will be shifted in a direction higher than the predetermined set value T1 thereafter. Accordingly, 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 reduced, in other words, so as to reduce the opening of the 2 nd damper 53 and/or increase the opening of the 1 st damper 52. When the temperature predicted by the temperature predicting unit 50c is lower than the predetermined set value T1, for example, the measured value T predicted as the thermometer 51 is shifted in a direction lower than the predetermined set value T1. Accordingly, 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 increases, in other words, corrects the opening of the 2 nd damper 53 and/or reduces the opening of the 1 st damper 52.
According to modification 1, even for a sudden temperature change of the exhaust gas in the AQC14, the deviation of the measured value T of the thermometer 51 from the predetermined set value T1 can be promptly suppressed.
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 thereto. For example, in the waste heat recovery system of the present invention, the opening degree of at least one of the 1 st damper 52 and the 2 nd damper 53 may be adjusted by a manual operation of an operator.
Fig. 4 is a block diagram of damper control in the waste heat recovery system of 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 control device 74 controls at least one of the 1 st damper 52 and the 2 nd damper 53 in accordance with the operation instruction 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 room of the cement sintering apparatus 1) 70 so that an operator can operate the operation device 73 based on an output of the output device 72. The output device 72 may be any output type that can transmit an instruction to the operator for the operation of the operation device 73, and may be, for example, a display or the like that can output an operation instruction screen, or a speaker or the like that can output an operation instruction by sound. For example, the output device 72 and the operation device 73 may be integrally formed, and may be a touch panel, for example. The command generating device 71 may be integrally formed with the output device 72.
According to the waste heat recovery system of modification 2, the operation instruction corresponding to the instruction value generated by the instruction generating device 71 is output to the output device 72. Therefore, the operator can be guided to perform an operation for maintaining the temperature of the gas flowing into the AQC boiler 30 to be constant with respect to the operation device 73. Therefore, this modification 2 can efficiently recover heat in the AQC boiler 30 as in the above embodiment.
The present invention is not limited to the above-described embodiments and modifications, and various modifications can be made without departing from the scope of the present invention.
For example, the 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) from the current time based on the measured value of the thermometer 101 provided on the AQC14 on the upstream side in the conveying direction of the sintered product than the high temperature portion 14c, and may correct the command value for bringing the measured value T of the thermometer 51 at the current time to the predetermined set value T1 based on the prediction result.
In the above embodiment, the 1 st damper 52 and the 2 nd damper 53 are described as the flow rate adjusting devices for adjusting the flow rate of the exhaust gas flowing through the 1 st exhaust pipe 43 and the 2 nd exhaust pipe 45, and the 3 rd damper 54 is described as the opening/closing device for opening/closing the inlet pipe 46, however, 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.
Claims (5)
1. In a cement sintering plant having a kiln for sintering cement raw materials and an air-cooled quenching cooler (AQC) for conveying and rapidly cooling a sinter fed from the kiln, a waste heat recovery system for recovering heat from exhaust gas generated by the AQC, the waste heat recovery system comprising:
a boiler that recovers heat from exhaust gas generated by the AQCs;
a 1 st exhaust pipe for guiding the exhaust gas discharged from the predetermined high temperature part of the AQC to the inlet of the boiler;
an exhaust device that exhausts exhaust gas after heat recovery by the boiler to the atmosphere;
a discharge pipe guiding exhaust gas discharged from an outlet of the boiler toward the discharge apparatus;
a 2 nd exhaust pipe that merges with the exhaust pipe an exhaust gas discharged from the low-temperature portion of the AQC located downstream of the high-temperature portion in a direction of conveying the sintered product;
a thermometer provided in the 1 st exhaust pipe and configured to measure a temperature of gas introduced into the boiler;
at least 1 flow rate adjustment device that adjusts a flow rate of exhaust gas flowing through at least one of the 1 st exhaust pipe and the 2 nd exhaust pipe; and
a command generating device that generates a command value for adjusting the at least 1 flow rate adjusting device so that a measured value of the thermometer approaches a prescribed set value, thereby being capable of maintaining a temperature of gas flowing into the boiler at the set value,
the thermometer is the 1 st thermometer,
a 2 nd thermometer is arranged on the upstream side of the AQC in the direction of conveying the sintered material relative to the high temperature part,
the command generating means 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 measured value of the 2 nd thermometer, and the predicted result is used for correcting the command value generated by the command generating means.
2. The waste heat recovery system according to claim 1, wherein,
the command generating means generates the command value that decreases at least the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe when the measured value of the 1 st thermometer is higher than the set value, and generates the command value that increases at least the flow rate of the exhaust gas flowing through the 2 nd exhaust pipe when the measured value of the 1 st thermometer is lower than the set value.
3. The waste heat recovery system according to claim 1 or 2, wherein,
the instruction generating means controls the at least 1 flow rate adjusting means according to the generated instruction value.
4. The waste heat recovery system according to claim 1 or 2, further comprising:
an operation device that receives an operation by an operator and generates an operation instruction;
control means for controlling the at least 1 flow rate adjustment means in accordance with the operation instruction; and
and an output device that outputs an operation instruction corresponding to the instruction value generated by the instruction generating device.
5. The waste heat recovery system according to claim 1 or 2, further comprising:
an introduction pipe connected to the 1 st exhaust pipe, for introducing a low-temperature gas having a temperature lower than that of the exhaust gas discharged from the high-temperature part of the AQC into the 1 st exhaust pipe; and
an opening/closing device provided in the introduction pipe,
the command generating means generates a command value for maintaining the state of closing the opening/closing device when the measured value of the 1 st thermometer is equal to or lower than a predetermined threshold value higher than the set value, and generates a command value for opening the opening/closing device when the temperature measured by the 1 st thermometer exceeds the threshold value.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910250059.9A CN111747667B (en) | 2019-03-29 | 2019-03-29 | Waste heat recovery system |
| JP2021511409A JP7209814B2 (en) | 2019-03-29 | 2020-03-18 | Exhaust heat recovery system |
| PCT/JP2020/011901 WO2020203280A1 (en) | 2019-03-29 | 2020-03-18 | Waste heat recovery system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910250059.9A CN111747667B (en) | 2019-03-29 | 2019-03-29 | Waste heat recovery system |
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| CN111747667A CN111747667A (en) | 2020-10-09 |
| CN111747667B true CN111747667B (en) | 2023-05-16 |
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| JP (1) | JP7209814B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS5969452A (en) * | 1982-10-07 | 1984-04-19 | 株式会社神戸製鋼所 | Use of exhaust gas of cement clinker cooling device |
| CN201706902U (en) * | 2010-06-30 | 2011-01-12 | 成都四通新能源技术有限公司 | Waste heat single-pressure recovery power generating system of dry method cement production line |
| CN101871732B (en) * | 2010-06-30 | 2012-02-01 | 成都四通新能源技术有限公司 | Dry method single-pressure recovery generating system of waste heat for cement production line |
| CN201787824U (en) | 2010-09-01 | 2011-04-06 | 西安思安新能源有限公司 | Waste heat generating device with waste heat taking port adjusting device and waste heat utilization system |
| CN201819571U (en) | 2010-09-21 | 2011-05-04 | 广东开能环保能源有限公司 | Kiln head exhaust device for cement exhaust-heat power generation |
| CN201876151U (en) * | 2010-10-20 | 2011-06-22 | 成都四通新能源技术有限公司 | Control system of smoke heat energy stepped utilization system |
| CN101949651B (en) * | 2010-10-20 | 2012-12-12 | 成都昊特新能源技术有限公司 | Afterheat double-voltage recovery and generation system of dry cement production line |
| US9551241B2 (en) * | 2012-07-02 | 2017-01-24 | Kawasaki Jukogyo Kabushiki Kaisha | Waste heat recovery power generation plant for sintering facility |
| CN104048500A (en) * | 2014-06-28 | 2014-09-17 | 陈霍旺 | Kiln head waste heat generating system of dry method rotary kiln device |
| CN206488639U (en) | 2017-01-16 | 2017-09-12 | 山东东华水泥有限公司 | Clinker line grate-cooler hot blast regulating system |
| CN206817995U (en) | 2017-05-26 | 2017-12-29 | 合肥水泥研究设计院 | A kind of online integral system of cement kiln waste heat recovery |
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| JPWO2020203280A1 (en) | 2021-11-04 |
| WO2020203280A1 (en) | 2020-10-08 |
| JP7209814B2 (en) | 2023-01-20 |
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