Waste heat recovery and reuse system and control method thereof

Abstract

The present invention provides a waste heat recovery and reuse system and a control method thereof, which belongs to the technical field of production process parameter control. The waste heat recovery and reuse system includes a heat exchanger, a firing kiln, a spray tower drying furnace, a green body drying furnace, an air volume regulating baffle, a fan, and temperature, pressure, flow measurement elements and transmitters. The high-temperature exhaust gas in the refining kiln is extracted by the fan, and the waste heat of the high-temperature flue gas is exchanged to the air through the heat exchanger. Then the hot air is used as the combustion-supporting air of the spray tower drying furnace and introduced into the green body drying furnace for drying ceramic green bodies, thereby reducing the fuel consumption in the spray tower drying furnace and the green body drying furnace, achieving the purpose of saving fuel, reducing carbon emissions, and improving corporate benefits. The control method is used to automatically control the process parameters of the waste heat recovery and reuse system, and according to the needs of on-site production, the waste heat derived from the exhaust gas is reasonably distributed to the spray tower drying furnace and the green body drying furnace to achieve the optimal distribution ratio and improve the efficiency of heat utilization.

Description

Technical Field

[0001] The present invention relates to the technical field of production process equipment, and in particular to a waste heat recovery and reuse system and a control method thereof. Background Art

[0002] At present, due to the efficiency constraints of the heat exchanger and system design defects in the ceramic firing production process, only a small part of the flue gas that has been fired at high temperature is extracted from the middle section of the firing kiln. After heat exchange in the heat exchanger, the heat is sent to the drying kiln to dry the green body. The remaining flue gas continues to fire the ceramic in the firing kiln, and is directly discharged into the desulfurization tower for spray cooling and then discharged into the air, which wastes a lot of energy. The temperature of the flue gas discharged into the desulfurization tower is relatively high. After the exhaust heat is recovered, it is used in the slurry and green body drying process in the ceramic manufacturing process. The value of flue gas waste heat recovery is huge. Summary of the invention

[0003] In view of this, an object of the present invention is to overcome the deficiencies in the prior art and to provide a waste heat recovery and reuse system and a control method thereof.

[0004] The present invention provides the following technical solutions: a waste heat recovery and reuse system, comprising a heat exchanger, a spray tower drying furnace, a green body drying furnace, a firing kiln, a first fan assembly, a second fan assembly, a first airflow duct, a second airflow duct, a third airflow duct, an exhaust fan, a first temperature closed-loop control circuit, an air pressure closed-loop control circuit, a second temperature closed-loop control circuit, a negative pressure closed-loop control circuit and an air volume open-loop control circuit;

[0005] The air outlet of the first fan assembly is connected to the air inlet of the heat exchanger through a pipeline, and the smoke inlet of the heat exchanger is connected to the smoke exhaust port of the firing kiln; the hot air outlet of the heat exchanger is connected to the air inlets of the second air flow pipeline and the third air flow pipeline respectively through the first air flow pipeline;

[0006] A first temperature sensor is installed on the first airflow pipeline, and a first pressure transmitter is installed on the third airflow pipeline;

[0007] The air outlet of the second air flow duct is connected to the combustion air inlets on both sides of the spray tower drying furnace through the first branch pipe and the second branch pipe, respectively, and the first branch pipe is equipped with a first air volume regulating baffle, and the second branch pipe is equipped with a second air volume regulating baffle;

[0008] The second fan assembly includes a second fan and a third fan;

[0009] The air outlet of the second fan is connected to the first branch pipe through a pipeline, and the air outlet of the second fan is located between the first air volume adjustment baffle and the combustion air inlet of the spray tower drying furnace;

[0010] The air outlet of the third fan is connected to the second branch pipe through a pipeline, and the air outlet of the third fan is located between the second air volume adjustment baffle and the combustion air inlet of the spray tower drying furnace;

[0011] The air outlet of the third air flow duct is connected to the green body drying furnace;

[0012] The third air flow duct is provided with a first pressure transmitter, a second flow transmitter, a second isolation baffle and a third air volume adjustment baffle;

[0013] The third air volume regulating baffle is located between the air inlet of the third air flow duct and the second isolation baffle, and the first pressure transmitter and the second flow transmitter are located between the air inlet of the third air flow duct and the third air volume regulating baffle;

[0014] The combustion chamber smoke outlet of the spray tower drying furnace is equipped with a second pressure transmitter and a second temperature sensor;

[0015] The air inlet of the exhaust fan is connected to the smoke outlet of the spray tower through a pipeline;

[0016] The first temperature closed-loop control circuit is electrically connected to the first fan assembly to control the rotation speed of the first fan assembly, thereby controlling the temperature of the hot air in the first airflow duct;

[0017] The wind pressure closed-loop control circuit is electrically connected to the first wind volume regulating damper and the second wind volume regulating damper respectively to control the opening of the first wind volume regulating damper or the second wind volume regulating damper, thereby controlling the pressure in the third air flow duct;

[0018] The second temperature closed-loop control circuit is electrically connected to the second fan assembly to control the rotation speed of the second fan assembly, thereby controlling the temperature of the smoke outlet of the combustion chamber of the spray tower drying furnace;

[0019] The negative pressure closed-loop control circuit is electrically connected to the exhaust fan to control the rotation speed of the exhaust fan, thereby controlling the pressure in the combustion chamber of the spray tower drying furnace;

[0020] The air volume open-loop control circuit is electrically connected to the third air volume adjustment baffle to control the air volume in the third air flow duct.

[0021] In some embodiments of the present invention, the first fan assembly includes a first fan and at least one first backup fan;

[0022] The first fan and the first standby fan are respectively connected to the air inlet of the heat exchanger through pipelines;

[0023] The first temperature closed-loop control circuit includes a first temperature sensor, a first PID temperature controller, a first switching component, a first frequency converter, a first standby frequency converter, the first fan and the first standby fan;

[0024] The input signal port of the first PID temperature controller is electrically connected to the first temperature sensor;

[0025] The output signal of the first PID temperature controller is electrically connected to the first frequency converter and the first standby frequency converter respectively through the first switching component;

[0026] The first frequency converter is electrically connected to the first fan, and the first standby frequency converter is electrically connected to the first standby fan;

[0027] The first frequency converter and the first standby frequency converter are electrically connected to a power source respectively.

[0028] Further, the wind pressure closed-loop control circuit includes a first pressure transmitter, a second PID controller, a second switching component, a first air volume regulating baffle and a second air volume regulating baffle;

[0029] The input signal port of the second PID controller is connected to the first pressure transmitter;

[0030] The output signal of the second PID controller is electrically connected to the first air volume regulating baffle and the second air volume regulating baffle respectively through the second switching component.

[0031] Further, the second temperature closed-loop control loop includes a second temperature sensor, a third PID temperature controller, a third switching component, a second frequency converter, a third frequency converter, the second fan and the third fan;

[0032] The input signal port of the third PID temperature controller is electrically connected to the second temperature sensor;

[0033] The output signal of the third PID temperature controller is electrically connected to the second frequency converter and the third frequency converter respectively through the third switching component;

[0034] The second frequency converter is electrically connected to the second fan, and the third frequency converter is electrically connected to the third fan;

[0035] The second frequency converter and the third frequency converter are electrically connected to a power source respectively.

[0036] Further, the negative pressure closed-loop control circuit includes a second pressure transmitter, a fourth PID controller, a fourth frequency converter and an exhaust fan;

[0037] The input signal port of the fourth PID controller is electrically connected to the second pressure transmitter;

[0038] The output signal of the fourth PID controller is electrically connected to the exhaust fan through the fourth frequency converter, and the air inlet of the exhaust fan is connected to the smoke exhaust port of the spray drying tower through a pipeline;

[0039] The fourth frequency converter is electrically connected to the power supply;

[0040] The air volume open-loop control circuit includes the second flow transmitter, the air volume manual controller and the third air volume adjustment damper;

[0041] The input signal port of the manual air volume controller is electrically connected to the second flow transmitter;

[0042] The output signal of the manual air volume controller is electrically connected to the third air volume adjustment baffle.

[0043] Some embodiments of the present invention further provide a control method, including the waste heat recovery and reuse system, and further comprising:

[0044] PID controller is a proportional, integral and differential controller, which is any combination of P, PI, PD or PID;

[0045] The first PID temperature controller is a temperature controller, the regulated variable is the hot air temperature in the second air flow duct, the regulated variable is the output air volume of the first fan assembly, the air volume is controlled by the PID output signal to control the motor frequency of the first fan assembly, and the outlet air volume is adjusted by adjusting the speed of the first fan assembly; the regulated variable is monitored by the first temperature sensor;

[0046] The second PID controller is a pressure controller, the regulated variable is the hot air pressure in the second air flow duct, and the regulating variable is the hot air flow in the second air flow duct. The flow size is controlled by the PID output signal to control the opening of the first air volume regulating damper or the second air volume regulating damper to adjust the hot air flow size in the second air flow duct; the regulated variable is monitored by the first pressure transmitter;

[0047] The third PID temperature controller is a temperature controller, the regulated variable is the outlet smoke temperature of the spray tower drying combustion chamber, the regulated variable is the outlet air volume of the second fan or the third fan, the air volume is controlled by the PID output signal to control the frequency of the second fan or the third fan, and the outlet air volume of the spray tower drying combustion chamber is adjusted by adjusting the speed of the second fan or the third fan; the regulated variable is monitored by the second temperature sensor;

[0048] The fourth PID controller is a negative pressure controller. The regulated variable is the negative pressure in the combustion chamber of the spray tower drying furnace. The regulated variable is the exhaust flow rate of the spray drying tower. The exhaust flow rate is controlled by the PID output signal to control the output frequency of the exhaust fan inverter. The exhaust flow rate is adjusted by adjusting the exhaust fan speed. The regulated variable is monitored by the second pressure transmitter.

[0049] Furthermore, the PID controller is a differential regulator, which performs P, I, and D operations on the deviation between the controlled variable and the set value, and then outputs a corresponding control signal;

[0050] The PID controller has the functions of LSP and RSP switching, A / M switching and disturbance-free switching;

[0051] LSP and RSP switching: The set value of the PID controller is switched between LSP and RSP through the L / R switch button on the controller. When switching to LSP, the LSP value is set on the PID controller; when switching to RSP, the set value is set remotely;

[0052] A / M switch: The PID controller has automatic and manual control functions, which are switched through the A / M switch button on the PID controller. When switched to manual mode, the PID controller output is manually changed by pressing the output signal increase and decrease buttons on the PID controller; when switched to automatic mode, the controller output is controlled by the PID controller.

[0053] Disturbance-free switching: The PID controller has a disturbance-free switching function. When switching between manual and automatic, the output signals track each other. That is, when the PID controller is in manual mode, the PID output tracks the manual output value. When it is switched to automatic mode, the PID controller output starts to adjust from the manual output value before switching. When the PID controller is in automatic mode, the manual output value tracks the PID output value. When it is switched to manual mode, the initial value of the PID controller output is the PID controller output value before switching.

[0054] Further, according to the heat demand of the green body drying furnace, the opening of the third air volume regulating damper is adjusted through the air volume open-loop control circuit to adjust the flow rate of hot air entering the green body drying furnace, so as to achieve the purpose of adjusting the heat introduced into the green body drying furnace;

[0055] The pressure in the third air flow duct is controlled to be stable by the first air volume regulating baffle or the second air volume regulating baffle to ensure that the hot air flow entering the green body drying furnace corresponds to the opening of the third air volume regulating baffle, thereby ensuring that the heat and air volume entering the green body drying furnace are controllable.

[0056] Furthermore, the third PID temperature controller and the second fan or the third fan are used to supplement the insufficient amount of combustion air input into the spray tower drying furnace through the second air flow duct, thereby controlling the flue gas temperature after the fuel in the spray tower drying furnace is burned, so that the flue gas temperature meets the slurry drying requirements in the spray tower.

[0057] Furthermore, the fourth PID controller and the exhaust fan are used to control the pressure in the spray tower drying furnace, so as to maintain negative pressure combustion in the spray tower drying furnace, ensure that the smoke and heat in the spray tower drying furnace do not overflow, and timely discharge the wet smoke in the spray drying tower.

[0058] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0060] Figure 1 A structural schematic diagram showing a perspective of a waste heat recovery and reuse system provided by some embodiments of the present invention;

[0061] Figure 2 Shows Figure 1 Enlarged view of part A in the middle;

[0062] Figure 3 A control principle diagram of a first temperature closed-loop control loop of a waste heat recovery and reuse system provided by some embodiments of the present invention is shown;

[0063] Figure 4 A control principle diagram of a wind pressure closed-loop control circuit in a waste heat recovery and reuse system provided by some embodiments of the present invention is shown;

[0064] Figure 5 A control principle diagram of a second temperature closed-loop control loop in a waste heat recovery and reuse system provided by some embodiments of the present invention is shown;

[0065] Figure 6 A control principle diagram of a negative pressure closed-loop control circuit in a waste heat recovery and reuse system provided by some embodiments of the present invention is shown;

[0066] Figure 7 A control principle diagram of the air volume in a green body drying furnace in a waste heat recovery and reuse system provided by some embodiments of the present invention is shown;

[0067] Figure 8 Shows Figure 1 Enlarged view of part B in the middle.

[0068] Description of main component symbols:

[0069] 10-heat exchanger; 20-spray tower drying furnace; 30-green drying furnace; 40-first fan assembly; 50-first airflow duct; 60-second airflow duct; 70-third airflow duct; 80-first temperature sensor; 90-first pressure transmitter; 100-second temperature sensor; 110-second pressure transmitter; 40a-first fan; 40b-first standby fan; 120-first branch pipe; 130-second branch pipe; 140-first air volume regulating baffle; 150-second fan assembly; 151-second fan; 152-third fan; 160-second air volume regulating baffle; 170-exhaust fan; 180-first flow transmitter; 190-first isolation baffle; 200-second flow Volume transmitter; 210-second isolation baffle; 220-third air volume adjustment baffle; 230-manual air volume controller; 240-first temperature closed-loop control circuit; 241-first PID temperature controller; 242-first switching component; 243-first frequency converter; 244-first standby frequency converter; 250-wind pressure closed-loop control circuit; 251-second PID controller; 252-second switching component; 260-second temperature closed-loop control circuit; 261-third PID temperature controller; 262-third switching component; 263-second frequency converter; 264-third frequency converter; 270-negative pressure closed-loop control circuit; 271-fourth PID controller; 272-fourth frequency converter; 280-firing kiln. DETAILED DESCRIPTION

[0070] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0071] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0072] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0074] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of the template are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0075] like Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, some embodiments of the present invention provide a waste heat recovery and reuse system, which is mainly used for the recovery and utilization of heat in the flue gas generated in the ceramic firing process in the ceramic industry. The waste heat recovery and reuse system includes a heat exchanger 10, a spray tower drying furnace 20, a green body drying furnace 30, a firing kiln 280, a first fan assembly 40, a second fan assembly 150, a first airflow duct 50, a second airflow duct 60, a third airflow duct 70, an exhaust fan 170, a first temperature closed-loop control circuit 240, a wind pressure closed-loop control circuit 250, a second temperature closed-loop control circuit 260, a negative pressure closed-loop control circuit 270 and an air volume open-loop control circuit. Specifically, the heat exchanger 10 is a device used to transfer heat from a hot fluid to a cold fluid to meet the specified process requirements, and is an industrial application of convective heat transfer and heat conduction. The spray tower drying furnace 20 is a device that can simultaneously complete drying and granulation, and the green body drying kiln is used to dry the ceramic green bodies generated in the ceramic production process in the ceramic industry.

[0076] It should be noted that the heat exchanger 10 described in some embodiments of the present invention is connected to the exhaust pipe of the firing kiln 280. Specifically, the flue gas inlet of the heat exchange is connected to the exhaust pipe after the fuel is burned during the ceramic firing process, and the flue gas outlet of the heat exchanger 10 is connected to the desulfurization tower through a pipe.

[0077] The smoke exhaust duct mentioned here is the smoke exhaust duct at the rear of the firing kiln 280. The heat of the smoke in the smoke exhaust duct is extracted by the cold air flowing through the air duct of the heat exchanger 10, which is used to increase the initial temperature of the combustion air of the spray tower drying furnace 20 for fuel combustion. At the same time, the hot air is introduced into the green body drying furnace 30 to dry the ceramic green bodies, thereby achieving the purpose of saving fuel, reducing emissions and improving enterprise benefits.

[0078] The air outlet of the first fan assembly 40 is connected to the air inlet of the heat exchanger 10 through a pipeline, and the air outlet of the heat exchanger 10 is respectively connected to the air inlet of the second airflow duct 60 and the air inlet of the third airflow duct 70 through the first airflow duct 50. That is, the air outlet of the heat exchanger 10 is connected to the air inlet of the first airflow duct 50, and the air outlet of the first airflow duct 50 is respectively connected to the air inlet of the second airflow duct 60 and the air inlet of the third airflow duct 70.

[0079] A first temperature sensor 80 is installed on the first airflow duct 50. It is understandable that the first temperature sensor 80 monitors the temperature of the hot air in the first airflow duct 50, that is, the temperature of the air discharged through the air outlet of the heat exchanger 10.

[0080] At the same time, the air outlet of the second air flow duct 60 is connected to the combustion air inlets on both sides of the spray tower drying furnace 20 through the first branch branch 120 and the second branch branch 130 respectively, and the first branch branch 120 is equipped with a first air volume regulating baffle 140, and the second branch branch 130 is equipped with a second air volume regulating baffle 160, and the opening of the first air volume regulating baffle 140 is controlled to adjust the flow rate of the gas flowing through the first branch branch 120 into the spray tower drying furnace 20, or the opening of the second air volume regulating baffle 160 is controlled to adjust the flow rate of the gas flowing through the second branch branch 130 into the spray tower drying furnace 20.

[0081] In some embodiments of the present invention, the second fan assembly 150 includes a second fan 151 and a third fan 152 .

[0082] The air outlet of the second fan 151 is connected to the first branch pipe 120 through a pipeline, and the air outlet of the second fan 151 is located between the first air volume adjustment baffle 140 and the combustion air inlet of the spray tower drying furnace 20.

[0083] In addition, the air outlet of the third fan 152 is connected to the second branch pipe 130 through a pipeline, and the air outlet of the third fan 152 is located between the second air volume adjustment baffle 160 and the combustion air inlet of the spray tower drying furnace 20.

[0084] It should be noted that the second fan 151 and the third fan 152 are used to adjust the flow rate of cold air entering the spray tower drying furnace 20, thereby adjusting the flue gas outlet temperature of the combustion chamber of the spray tower drying furnace 20 to meet the slurry drying needs in the spray tower drying furnace 20.

[0085] In addition, the second fan 151 and the third fan 152 serve as supplements to the combustion-supporting air volume in the first branch branch 120 and the second branch branch 130. When the combustion-supporting air volume in the first branch branch 120 and the second branch branch 130 is insufficient to support the required fuel combustion air volume (the outlet temperature of the combustion chamber of the spray tower drying furnace 20 is low), the insufficient combustion-supporting air volume can be supplemented by adjusting the load of the second fan 151 and the third fan 152.

[0086] In addition, the air outlet of the third airflow duct 70 is connected to the green body drying furnace 30. It is understandable that the high-temperature hot air discharged from the first airflow duct 50 can flow into the green body drying furnace 30 through the third airflow duct 70.

[0087] At the same time, a second pressure transmitter 110 and a second temperature sensor 100 are installed at the smoke outlet of the combustion chamber of the spray tower drying furnace 20, which are used to monitor the pressure of the smoke outlet of the combustion chamber of the spray tower drying furnace 20 through the second pressure transmitter 110, and monitor the temperature of the smoke outlet of the combustion chamber of the spray tower drying furnace 20 through the second temperature sensor 100.

[0088] It should be noted that a pressure transmitter is a device that converts pressure into an electrical signal. It can convert the physical pressure of gas, liquid, etc. sensed by the pressure measuring element sensor into a standard electrical signal (such as 4-20mADC, etc.) output to supply secondary instruments such as remote indication alarms, recorders, regulators, etc. to measure, indicate and adjust the monitored pressure.

[0089] By connecting the air inlet of the exhaust fan 170 to the smoke outlet of the spray tower drying furnace 20 through a pipeline, the pressure in the combustion chamber of the spray tower drying furnace 20 is adjusted by the exhaust fan 170, thereby improving the stability of the pressure in the combustion chamber of the spray tower drying furnace 20.

[0090] In some embodiments of the present invention, the second airflow duct 60 is provided with a first isolation baffle 190 and a first flow transmitter 180, and the first flow transmitter 180 is located between the first isolation baffle 190 and the air inlet of the second airflow duct 60. It can be understood that the flow rate of the hot air flowing through the second airflow duct 60 is monitored by the first flow transmitter 180.

[0091] It should be noted that when the first isolation baffle 190 is closed, no gas in the second air flow duct 60 flows toward the spray tower drying furnace 20 .

[0092] When the first isolation baffle 190 is opened, the gas in the first air flow duct 50 can flow into the spray tower drying furnace 20 through the second air flow duct 60 .

[0093] Among them, a second flow transmitter 200, a second isolation baffle 210, a first pressure transmitter 90 and a third air volume adjustment baffle 220 are provided on the third air flow duct 70, and the third air volume adjustment baffle 220 is located between the air inlet of the third air flow duct 70 and the second isolation baffle 210, and the second flow transmitter 200 and the first pressure transmitter 90 are located between the air inlet of the third air flow duct 70 and the third air volume adjustment baffle 220.

[0094] Specifically, when the second isolation baffle 210 is closed, no gas in the third air flow duct 70 flows into the green body drying furnace 30 .

[0095] When the second isolation baffle 210 is opened, the gas in the first airflow duct 50 can flow into the green drying furnace 30 through the third airflow duct 70, and the air flow in the third airflow channel can be adjusted by adjusting the opening of the third air volume adjustment baffle 220.

[0096] It should be noted that the first temperature closed-loop control circuit 240 is electrically connected to the first fan assembly 40 to control the rotation speed of the first fan assembly 40 , thereby controlling the temperature of the hot air in the first airflow duct 50 .

[0097] Among them, the wind pressure closed-loop control circuit 250 is electrically connected to the first air volume regulating baffle 140 and the second air volume regulating baffle 160 respectively, and the air volume in the second air flow duct is adjusted by controlling the opening of the first air volume regulating baffle 140 or the second air volume regulating baffle 160, so as to adjust the pressure in the third air flow duct 70.

[0098] In addition, the second temperature closed-loop control circuit 260 is electrically connected to the second fan assembly 150 to control the rotation speed of the second fan assembly 150 and adjust the amount of combustion air entering the spray tower drying furnace 20, thereby adjusting the flue gas temperature at the combustion chamber outlet of the spray tower drying furnace 20.

[0099] At the same time, the negative pressure closed-loop control circuit 270 is electrically connected to the exhaust fan 170 to control the rotation speed of the exhaust fan 170 and adjust the smoke exhaust volume of the spray tower drying furnace 20, thereby controlling the pressure in the combustion chamber of the spray tower drying furnace 20.

[0100] In some embodiments of the present invention, the air volume open-loop control circuit includes the second flow transmitter 200, the air volume manual controller 230 and the third air volume adjustment damper 220. The input signal port of the air volume manual controller 230 is electrically connected to the second flow transmitter 200, and the output signal of the air volume manual controller 230 is electrically connected to the third air volume adjustment damper 220.

[0101] It is understandable that the opening of the third air volume regulating damper 220 can be controlled by the air volume manual controller 230, so as to adjust the flow rate of the gas flowing through the third air flow duct 70.

[0102] like Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the first fan assembly 40 includes a first fan 40a and at least one first standby fan 40b. It can be understood that the first fan assembly 40 includes a first fan 40a and one first standby fan 40b. Or the first fan assembly 40 includes a first fan 40a and multiple first standby fans 40b, wherein the number of first standby fans 40b can be two or more of any value, which can be specifically set according to actual conditions.

[0103] Specifically, in some embodiments of the present invention, the first fan assembly 40 includes a first fan 40a and a first standby fan 40b, and the two fans are used as a backup for each other. It should be noted that when the operating fan fails, the standby fan can be switched to operate, thereby improving the stability and safety of the first fan assembly 40 during operation.

[0104] The first fan 40a and the first standby fan 40b are connected to the air inlet of the heat exchanger 10 through pipes, respectively, so that the cold air enters the heat exchanger 10 through the first fan 40a or the first standby fan 40b through the pipe and the air inlet of the heat exchanger 10. The cold air entering the heat exchanger 10 is heated by the high-temperature flue gas in the heat exchanger 10 to form hot air, and flows into the first air flow channel from the air outlet of the heat exchanger 10. The air volume entering the heat exchanger 10 can be adjusted by adjusting the operating load of the first fan 40a, thereby adjusting the air temperature at the air outlet of the heat exchanger 10. Figure 1 , Figure 3As shown, in some embodiments of the present invention, the first temperature closed-loop control circuit 240 includes a first temperature sensor 80, a first PID temperature controller 241, a first switching component 242, a first frequency converter 243, a first standby frequency converter 244, the first fan 40a and the first standby fan 40b.

[0105] The input signal port of the first PID temperature controller 241 is electrically connected to the first temperature sensor 80 , and the output signal of the first PID temperature controller 241 is electrically connected to the first frequency converter 243 and the first standby frequency converter 244 respectively through the first switching component 242 .

[0106] In addition, the first frequency converter 243 is electrically connected to the first fan 40a, and the power frequency of the first fan 40a is adjusted by the first frequency converter 243, and the first standby frequency converter 244 is electrically connected to the first standby fan 40b, and the power frequency of the first standby fan 40b is adjusted by the first standby frequency converter 244, and the first frequency converter 243 and the first standby frequency converter 244 are electrically connected to the power supply, respectively.

[0107] Specifically, the first temperature sensor 80 is used to monitor the gas temperature in the first airflow duct 50 in real time, and the monitored temperature value is sent to the first PID temperature controller 241 through a signal. The first PID temperature controller 241 receives the temperature value signal and performs PID operation. The first PID temperature controller 241 controls the frequency of the output power of the first frequency converter 243 or the first standby frequency converter 244 according to the operation result to adjust the rotation speed of the first fan 40a or the first standby fan 40b, so as to achieve the purpose of adjusting the gas temperature in the first airflow duct 50.

[0108] like Figure 1 , Figure 4 As shown, in some embodiments of the present invention, the wind pressure closed-loop control circuit 250 includes a first pressure transmitter 90 , a second PID controller 251 , a second switching component 252 , a first air volume regulating damper 140 and a second air volume regulating damper 160 .

[0109] Among them, the input signal port of the second PID controller 251 is connected to the first pressure transmitter 90, and the output signal of the second PID controller 251 is electrically connected to the first air volume adjustment baffle 140 and the second air volume adjustment baffle 160 respectively through the second switching component 252, and the opening of the first air volume adjustment baffle 140 or the second air volume adjustment baffle 160 is adjusted by the second switching component 252, and the pressure in the third air flow duct 70 is adjusted by adjusting the air flow in the second air flow duct.

[0110] Specifically, the pressure in the third air flow duct 70 is monitored in real time by the first pressure transmitter 90, and the monitored pressure value is sent to the second PID controller 251 through a signal. The second PID controller 251 receives the pressure value signal and performs PID operation. The second PID controller 251 controls the opening of the first air volume adjustment baffle 140 or the second air volume adjustment baffle 160 according to the operation result.

[0111] like Figure 1 , Figure 5 As shown, in some embodiments of the present invention, the second temperature closed-loop control circuit 260 includes a third PID temperature controller 261, a third switching component 262, a second frequency converter 263, a third frequency converter 264, the second fan 151 and the third fan 152.

[0112] Among them, the input signal port of the third PID temperature controller 261 is connected to the second temperature sensor 100, and the output signal of the third PID temperature controller 261 is electrically connected to the second frequency converter 263 and the third frequency converter 264 respectively through the third switching component 262, the second frequency converter 263 is electrically connected to the second fan 151, and the power frequency of the second fan 151 is adjusted by the second frequency converter 263, the third frequency converter 264 is electrically connected to the third fan 152, and the power frequency of the third fan 152 is adjusted by the third frequency converter 264.

[0113] In addition, the second frequency converter 263 and the third frequency converter 264 are electrically connected to a power source, respectively.

[0114] The monitored temperature signal is sent to the third PID temperature controller 261 through the second temperature sensor 100, and the third PID temperature controller receives the temperature value signal to perform PID operation. The operation result controls the output power frequency of the second frequency converter 263 or the third frequency converter 264, thereby controlling the power frequency of the second fan 151 and the third fan 152 to adjust the rotation speed of the second fan 151 or the third fan 152, so as to achieve the purpose of adjusting the combustion-aiding air volume.

[0115] like Figure 1 , Figure 6 As shown, in some embodiments of the present invention, the negative pressure closed-loop control circuit 270 includes a second pressure transmitter 110 , a fourth PID controller 271 , a fourth frequency converter 272 and an exhaust fan 170 .

[0116] The input signal port of the fourth PID controller 271 is electrically connected to the second pressure transmitter 110, the output signal of the fourth PID controller 271 is electrically connected to the exhaust fan 170 through the fourth frequency converter 272, and the fourth frequency converter 272 is electrically connected to the power supply. The air inlet of the exhaust fan 170 is connected to the smoke exhaust port of the spray drying tower through a pipeline.

[0117] The monitored pressure signal is sent to the fourth PID temperature controller through the second pressure transmitter 110, and the fourth PID controller 271 receives the pressure value signal to perform PID operation. The operation result controls the output power frequency of the fourth inverter 272 and adjusts the rotation speed of the exhaust fan 170, thereby adjusting the exhaust volume of the spray tower drying furnace to achieve the purpose of adjusting the pressure in the drying furnace.

[0118] like Figures 1 to 8 As shown, some embodiments of the present invention further provide a control method, wherein the waste heat recovery and reuse system described in any one of the above embodiments comprises the following contents:

[0119] PID controller is a proportional, integral and differential controller, which is any combination of P (proportion), PI (proportion integral), PD (proportion derivative) or PID (proportion integral derivative).

[0120] It should be noted that the first PID temperature controller 241 is a temperature controller, the regulated variable is the hot air temperature in the first airflow duct 50, the regulated variable is the output air volume of the first fan assembly 40, and the air volume is controlled by the PID output signal to control the motor speed of the first fan assembly 40, thereby adjusting the air volume at the machine outlet and thus adjusting the temperature; the regulated variable of the first PID temperature controller 241 is monitored by the first temperature sensor 80.

[0121] Specifically, when the first temperature sensor 80 detects that the hot air temperature value in the first airflow duct 50 is greater than or less than the set temperature, the first PID temperature controller 241 automatically adjusts the size, direction and increase or decrease speed of the output signal of the first PID temperature controller 241 through the size, direction and change speed of the deviation signal through PID operation, thereby adjusting the output power frequency of the first frequency converter 243 or the first standby frequency converter 244, controlling the rotation speed of the first fan 40a and the first standby fan 40b, thereby adjusting the hot air flow in the first airflow duct 50, so that the hot air temperature in the first airflow duct is maintained at the set value of the first PID temperature controller 241.

[0122] When the first temperature sensor 80 detects that the hot air temperature in the first airflow duct 50 is equal to the set temperature value of the first PID temperature controller 241, the controller output signal remains unchanged, the motor frequency and speed of the first fan assembly 40 remain unchanged, and the air volume in the first airflow duct 50 remains unchanged, so the temperature remains unchanged; when the smoke flow rate decreases or the smoke temperature decreases, the first temperature sensor 80 detects that the hot air temperature value in the first airflow duct 50 is less than the set temperature value, the first PID temperature controller 241 automatically reduces the first PID controller output signal according to the size and change speed of the deviation between the measured value and the set value, reduces the output power frequency of the first inverter 243 and the first standby inverter 244, thereby reducing the motor speed of the first fan assembly 40, reducing the air flow in the first airflow duct 50, and maintaining the hot air temperature in the first airflow duct 50 at the set value; when the smoke flow rate increases or the smoke temperature rises, the output of the first PID controller, the inverter power output frequency, the motor speed, and the air volume change in the opposite direction.

[0123] Among them, the second PID controller 251 is a pressure controller, the regulated variable is the hot air pressure in the third air flow duct 70, and the regulating variable is the hot air flow in the second air flow duct 60. The flow rate is controlled by the PID output signal to control the opening of the first air volume regulating baffle 140 or the second air volume regulating baffle 160, and the hot air flow in the second air flow duct 60 is adjusted to maintain the hot air pressure in the third air flow duct 70 at the set pressure; the regulated variable of the second PID controller 251 is monitored by the first pressure transmitter 90.

[0124] When the first pressure transmitter 90 detects that the pressure in the third airflow duct 70 is equal to the set temperature value of the second PID controller 251, the controller output signal remains unchanged, the openings of the first air volume regulating damper 140 and the second air volume regulating damper 160 remain unchanged, and the air volume in the second airflow duct 60 remains unchanged, so the pressure in the second airflow duct remains unchanged; when the speed of the first fan assembly 40 decreases, or the opening of the third air volume regulating damper 220 increases, the first pressure transmitter 90 detects that the hot air pressure in the third airflow duct 70 is less than the set pressure, the second PID controller 251 According to the size and change speed of the deviation between the measured value and the set value, the output signal of the second PID controller 251 is automatically reduced, and the opening of the first air volume regulating damper 140 or the second air volume regulating damper 160 is reduced, thereby reducing the air flow in the second air flow duct 60, so that the hot air pressure in the third air flow duct 70 is maintained at the set value; when the speed of the first fan assembly 40 increases, or the opening of the third air volume regulating damper 220 decreases, the output of the second PID controller 251 is increased, and the opening of the first air volume regulating damper 140 or the second air volume regulating damper 160 changes in the opposite direction.

[0125] In addition, the third PID temperature controller 261 is a temperature controller, and the regulated variable is the smoke temperature at the outlet of the combustion chamber of the spray tower drying furnace 20, and the regulated variable is the outlet air volume of the second fan 151 or the third fan 152. The air volume is controlled by the output signal of the third PID temperature controller 261 to control the output power frequency of the second frequency converter 263 or the third frequency converter 264, thereby controlling the speed of the second fan 151 or the third fan 152 to adjust the size of the supplementary combustion air volume, so as to achieve the purpose of adjusting the smoke temperature at the outlet of the combustion chamber of the spray tower drying furnace 20; the regulated variable of the third PID temperature controller 261 is monitored by the second temperature sensor 100.

[0126] Specifically, when the second temperature sensor 100 monitors that the outlet smoke temperature of the combustion chamber of the spray tower drying furnace 20 is equal to the set temperature value of the third PID temperature controller 261, the controller output signal remains unchanged, the output power frequency of the second frequency converter 263 and the third frequency converter 264 remains unchanged, the rotation speed of the second fan 151 and the third fan 152 remains unchanged, and the combustion-supporting supplementary air volume of the combustion chamber of the spray tower drying furnace 20 remains unchanged, thereby maintaining the outlet smoke temperature of the combustion chamber of the spray tower drying furnace 20 unchanged; when the opening of the first air volume regulating damper 140 or the second air volume regulating damper 160 is reduced, and the amount of combustion-supporting hot air entering the spray tower drying furnace 20 is reduced, the second temperature sensor 100 monitors that the outlet smoke temperature of the combustion chamber of the spray tower drying furnace 20 is less than the set temperature, the third PID temperature controller 261 adjusts the measured value according to the measured value. The size and change speed of the deviation from the set value automatically increase the output signal of the third PID temperature controller 261, increase the output power frequency of the second frequency converter 263 and the third frequency converter 264, increase the rotation speed of the second fan 151 and the third fan 152, increase the combustion-supporting supplementary air volume of the spray tower drying furnace 20 combustion chamber, thereby maintaining the outlet smoke temperature of the spray tower drying furnace 20 combustion chamber; when the opening of the first air volume regulating damper 140 or the second air volume regulating damper 160 increases, and the combustion-supporting hot air volume entering the spray tower drying furnace 20 increases, the output of the third PID temperature controller 261, the output power frequency of the second frequency converter 263 and the third frequency converter 264 are reduced, and the rotation speed of the second fan 151 and the third fan 152, and the combustion-supporting supplementary air volume entering the combustion chamber of the spray tower drying furnace 20 change in the opposite direction.

[0127] In addition, the fourth PID controller 271 is a negative pressure controller, the regulated variable is the pressure in the combustion chamber of the spray tower drying furnace 20, and the regulated variable is the exhaust flow rate of the spray drying tower. The exhaust flow rate is controlled by the PID output signal to control the power frequency output by the fourth frequency converter 272, and the exhaust flow rate is adjusted by adjusting the speed of the exhaust fan 170; the regulated variable of the fourth PID controller 271 is monitored by the second pressure transmitter 110.

[0128] Specifically, when the second pressure transmitter 110 monitors that the outlet pressure of the combustion chamber of the spray tower drying furnace 20 is equal to the set pressure value of the fourth PID controller 271, the controller output signal remains unchanged, the output power frequency of the fourth frequency converter 272 remains unchanged, the speed of the exhaust fan 170 remains unchanged, and the exhaust flow rate of the spray tower drying furnace remains unchanged, so as to keep the outlet pressure of the combustion chamber of the spray tower drying furnace 20 at the set value; when the speed of the second fan 151 or the third fan 152 increases, or the opening of the first air volume regulating baffle 140 or the second air volume regulating baffle 160 increases, and the flow rate of combustion-supporting air entering the combustion chamber of the spray tower drying furnace 20 increases, the second pressure transmitter 110 monitors that the outlet pressure of the combustion chamber of the spray tower drying furnace 20 increases, and the fourth PID controller 271 adjusts the combustion chamber pressure according to the deviation between the measured value and the set value. The size and change speed of the fourth PID controller 271 are automatically increased, the output signal of the fourth PID controller 271 is increased, the output power frequency of the fourth inverter 272 is increased, the rotation speed of the exhaust fan 170 is increased, and the exhaust volume of the spray tower drying furnace 20 is increased, so as to maintain the outlet pressure of the combustion chamber of the spray tower drying furnace 20 unchanged; when the rotation speed of the second fan 151 or the third fan 152 is reduced, or the opening of the first air volume regulating baffle 140 or the second air volume regulating baffle 160 is reduced, and the flow rate of combustion-supporting air entering the combustion chamber of the spray tower drying furnace 20 is reduced, the second pressure transmitter 110 monitors that the outlet pressure of the combustion chamber of the spray tower drying furnace 20 is reduced, the fourth PID controller 271 outputs a signal, the fourth inverter 272 outputs a power frequency, the rotation speed of the exhaust fan 170, and the exhaust volume of the spray tower drying furnace 20 change in the opposite way.

[0129] It should be noted that the PID controller is a differential regulator, which performs P (proportion), I (integral), and D (derivative) operations on the deviation between the controlled variable and the set value, and then outputs a corresponding control signal.

[0130] The controller has the functions of LSP and RSP switching, A / M (Automatic / Manual) switching and non-disturbance switching:

[0131] LSP and RSP switching: The setpoint of the PID controller is switched between LSP and RSP through the L / R (LSP / RSP) switch button on the controller. When switching to LSP (local setpoint), the LSP value is set on the controller; when switching to RSP (remote setpoint), the setpoint is set remotely;

[0132] A / M (Automatic / Manual) switching: The PID controller has automatic and manual control functions, which are switched through the A / M switching button on the controller. When switched to manual mode, the controller output is manually changed by controlling the output signal increase and decrease buttons on the controller; when switched to automatic mode, the controller output is controlled by the PID controller.

[0133] Disturbance-free switching: The PID controller has a disturbance-free switching function. When switching between manual and automatic, the output signals track each other. That is, when the controller is in manual mode, the PID output tracks the manual output value. When it is switched to automatic mode, the PID controller output starts to adjust from the manual output value before switching. When the controller is in automatic mode, the manual output value tracks the PID output value. When it is switched to manual mode, the initial value of the controller output is the PID controller output value before switching.

[0134] like Figure 1 and Figure 3 As shown, in some embodiments of the present invention, according to the production temperature requirement of the green body drying furnace 30, the speed of the first fan assembly 40 is adjusted through the first temperature closed-loop control circuit 240, thereby adjusting the air flow in the first air flow duct 50 to achieve the purpose of adjusting the hot air temperature in the first air flow duct 50.

[0135] In addition, the pressure in the third air flow duct 70 is controlled to be stable through the wind pressure closed-loop control circuit 250, ensuring that the hot air flow entering the green body drying furnace 30 and the opening of the third air volume regulating damper 220 are in a corresponding relationship, thereby ensuring that the heat and air volume entering the green body drying furnace 30 are controlled by the third air volume regulating damper 220.

[0136] like Figure 1 and Figure 5 As shown, in some embodiments of the present invention, the second temperature closed-loop control circuit 260 controls the speed of the second fan 151 or the third fan 152, adjusts the amount of combustion air in the spray tower drying furnace 20, and supplements the insufficient amount of combustion air input into the spray tower drying furnace 20 through the second air flow duct 60, thereby adjusting the flue gas temperature after fuel combustion in the spray tower drying furnace 20, so that the flue gas temperature meets the slurry drying in the spray tower.

[0137] like Figure 1 and Figure 6 As shown, in some embodiments of the present invention, the negative pressure closed-loop control circuit 270 is used to control the pressure inside the spray tower drying furnace 20, so that negative pressure combustion is maintained in the spray tower drying furnace 20, ensuring that the smoke and heat in the spray tower drying furnace 20 do not overflow, and at the same time, the wet smoke in the spray drying tower is discharged in time, the internal smoke humidity is reduced, and the negative pressure in the spray tower is maintained, which is more conducive to the vaporization of water in the slurry.

[0138] The opening of the third air volume regulating damper 220 is adjusted through an air volume open-loop control circuit, thereby adjusting the flow rate of hot air entering the green body drying furnace 30 .

[0139] Specifically, according to production needs, when the amount of hot air flowing into the green body drying furnace 30 needs to be increased, the air volume manual controller 230 in the air volume open-loop control circuit is used to increase the opening of the third air volume regulating baffle 220, thereby increasing the flow of hot air entering the green body drying furnace 30; when the amount of hot air flowing into the green body drying furnace 30 needs to be reduced, the air volume manual controller 230 in the air volume open-loop control circuit is used to reduce the opening of the third air volume regulating baffle 220, thereby reducing the flow of hot air entering the green body drying furnace 30.

[0140] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limiting, and thus other examples of the exemplary embodiments may have different values.

[0141] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0142] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A waste heat recovery and reuse system, characterized in that: It includes a heat exchanger, a spray tower drying furnace, a green body drying furnace, a firing kiln, a first fan assembly, a second fan assembly, a first airflow duct, a second airflow duct, a third airflow duct, an exhaust fan, a first temperature closed-loop control circuit, an air pressure closed-loop control circuit, a second temperature closed-loop control circuit, a negative pressure closed-loop control circuit and an air volume open-loop control circuit; The air outlet of the first fan assembly is connected to the air inlet of the heat exchanger through a pipeline, and the smoke inlet of the heat exchanger is connected to the smoke exhaust port of the firing kiln; the hot air outlet of the heat exchanger is connected to the air inlets of the second air flow pipeline and the third air flow pipeline respectively through the first air flow pipeline; A first temperature sensor is installed on the first airflow pipeline, and a first pressure transmitter is installed on the third airflow pipeline; The air outlet of the second air flow duct is connected to the combustion air inlets on both sides of the spray tower drying furnace through the first branch pipe and the second branch pipe, respectively, and the first branch pipe is equipped with a first air volume regulating baffle, and the second branch pipe is equipped with a second air volume regulating baffle; The second fan assembly includes a second fan and a third fan; The air outlet of the second fan is connected to the first branch pipe through a pipeline, and the air outlet of the second fan is located between the first air volume adjustment baffle and the combustion air inlet of the spray tower drying furnace; The air outlet of the third fan is connected to the second branch pipe through a pipeline, and the air outlet of the third fan is located between the second air volume adjustment baffle and the combustion air inlet of the spray tower drying furnace; The air outlet of the third air flow duct is connected to the green body drying furnace; The third air flow duct is provided with a first pressure transmitter, a second flow transmitter, a second isolation baffle and a third air volume adjustment baffle; The third air volume regulating baffle is located between the air inlet of the third air flow duct and the second isolation baffle, and the first pressure transmitter and the second flow transmitter are located between the air inlet of the third air flow duct and the third air volume regulating baffle; The combustion chamber smoke outlet of the spray tower drying furnace is equipped with a second pressure transmitter and a second temperature sensor; The air inlet of the exhaust fan is connected to the smoke outlet of the spray tower through a pipeline; The first temperature closed-loop control circuit is electrically connected to the first fan assembly to control the rotation speed of the first fan assembly, thereby controlling the temperature of the hot air in the first airflow duct; The wind pressure closed-loop control circuit is electrically connected to the first wind volume regulating damper and the second wind volume regulating damper respectively to control the opening of the first wind volume regulating damper or the second wind volume regulating damper, thereby controlling the pressure in the third air flow duct; The second temperature closed-loop control circuit is electrically connected to the second fan assembly to control the rotation speed of the second fan assembly, thereby controlling the temperature of the smoke outlet of the combustion chamber of the spray tower drying furnace; The negative pressure closed-loop control circuit is electrically connected to the exhaust fan to control the rotation speed of the exhaust fan, thereby controlling the pressure in the combustion chamber of the spray tower drying furnace; The air volume open-loop control circuit is electrically connected to the third air volume adjustment baffle to control the air volume in the third air flow duct.

2. The waste heat recovery and reuse system according to claim 1, characterized in that: The first fan assembly includes a first fan and at least one first standby fan; The first fan and the first standby fan are respectively connected to the air inlet of the heat exchanger through pipelines; The first temperature closed-loop control circuit includes a first temperature sensor, a first PID temperature controller, a first switching component, a first frequency converter, a first standby frequency converter, the first fan and the first standby fan; The input signal port of the first PID temperature controller is electrically connected to the first temperature sensor; The output signal of the first PID temperature controller is electrically connected to the first frequency converter and the first standby frequency converter respectively through the first switching component; The first frequency converter is electrically connected to the first fan, and the first standby frequency converter is electrically connected to the first standby fan; The first frequency converter and the first standby frequency converter are electrically connected to a power source respectively.

3. The waste heat recovery and reuse system according to claim 1, characterized in that: The wind pressure closed-loop control circuit includes a first pressure transmitter, a second PID controller, a second switching component, a first air volume regulating baffle and a second air volume regulating baffle; The input signal port of the second PID controller is connected to the first pressure transmitter; The output signal of the second PID controller is electrically connected to the first air volume regulating baffle and the second air volume regulating baffle respectively through the second switching component.

4. The waste heat recovery and reuse system according to claim 1, characterized in that: The second temperature closed-loop control loop includes a second temperature sensor, a third PID temperature controller, a third switching component, a second frequency converter, a third frequency converter, the second fan and the third fan; The input signal port of the third PID temperature controller is electrically connected to the second temperature sensor; The output signal of the third PID temperature controller is electrically connected to the second frequency converter and the third frequency converter respectively through the third switching component; The second frequency converter is electrically connected to the second fan, and the third frequency converter is electrically connected to the third fan; The second frequency converter and the third frequency converter are electrically connected to a power source respectively.

5. The waste heat recovery and reuse system according to claim 1, characterized in that: The negative pressure closed-loop control circuit includes a second pressure transmitter, a fourth PID controller, a fourth frequency converter and an exhaust fan; The input signal port of the fourth PID controller is electrically connected to the second pressure transmitter; The output signal of the fourth PID controller is electrically connected to the exhaust fan through the fourth frequency converter, and the air inlet of the exhaust fan is connected to the smoke exhaust port of the spray drying tower through a pipeline; The fourth frequency converter is electrically connected to the power supply; The air volume open-loop control circuit includes the second flow transmitter, the air volume manual controller and the third air volume adjustment damper; The input signal port of the manual air volume controller is electrically connected to the second flow transmitter; The output signal of the manual air volume controller is electrically connected to the third air volume adjustment baffle.

6. A control method, characterized in that: The waste heat recovery and reuse system according to any one of claims 1 to 5 further comprises: PID controller is a proportional, integral and differential controller, which is any combination of P, PI, PD or PID; The first PID controller is a temperature controller, the regulated variable is the hot air temperature in the second air flow duct, and the regulated variable is the output air volume of the first fan assembly. The air volume is controlled by the PID output signal to control the motor frequency of the first fan assembly, and the outlet air volume is adjusted by adjusting the speed of the first fan assembly; the regulated variable is monitored by the first temperature sensor; The second PID controller is a pressure controller, the regulated variable is the hot air pressure in the second air flow duct, and the regulating variable is the hot air flow in the second air flow duct. The flow size is controlled by the PID output signal to control the opening of the first air volume regulating damper or the second air volume regulating damper to adjust the hot air flow size in the second air flow duct; the regulated variable is monitored by the first pressure transmitter; The third PID temperature controller is a temperature controller, the regulated variable is the outlet smoke temperature of the spray tower drying combustion chamber, the regulated variable is the outlet air volume of the second fan or the third fan, the air volume is controlled by the PID output signal to control the frequency of the second fan or the third fan, and the outlet air volume of the spray tower drying combustion chamber is adjusted by adjusting the speed of the second fan or the third fan; the regulated variable is monitored by the second temperature sensor; The fourth PID controller is a negative pressure controller. The regulated variable is the negative pressure in the combustion chamber of the spray tower drying furnace. The regulated variable is the exhaust flow rate of the spray drying tower. The exhaust flow rate is controlled by the PID output signal to control the output frequency of the exhaust fan inverter. The exhaust flow rate is adjusted by adjusting the exhaust fan speed. The regulated variable is monitored by the second pressure transmitter.

7. The control method according to claim 6, characterized in that: The PID controller is a differential regulator, which performs P, I, and D operations on the deviation between the controlled variable and the set value, and then outputs the corresponding control signal. The PID controller has the functions of LSP and RSP switching, A / M switching and disturbance-free switching; LSP and RSP switching: The set value of the PID controller is switched between LSP and RSP through the L / R switch button on the controller. When switching to LSP, the LSP value is set on the PID controller; when switching to RSP, the set value is set remotely; A / M switch: The PID controller has automatic and manual control functions, which are switched through the A / M switch button on the PID controller. When switched to manual mode, the PID controller output is manually changed by pressing the output signal increase and decrease buttons on the PID controller; when switched to automatic mode, the controller output is controlled by the PID controller. Disturbance-free switching: The PID controller has a disturbance-free switching function. When switching between manual and automatic, the output signals track each other. That is, when the PID controller is in manual mode, the PID output tracks the manual output value. When it is switched to automatic mode, the PID controller output starts to adjust from the manual output value before switching. When the PID controller is in automatic mode, the manual output value tracks the PID output value. When it is switched to manual mode, the initial value of the PID controller output is the PID controller output value before switching.

8. The control method according to claim 6, characterized in that: According to the heat demand of the green body drying furnace, the opening of the third air volume regulating damper is adjusted through the air volume open-loop control circuit to adjust the flow of hot air entering the green body drying furnace, so as to achieve the purpose of adjusting the heat introduced into the green body drying furnace; The pressure in the third air flow duct is controlled to be stable by the first air volume regulating baffle or the second air volume regulating baffle to ensure that the hot air flow entering the green body drying furnace corresponds to the opening of the third air volume regulating baffle, thereby ensuring that the heat and air volume entering the green body drying furnace are controllable.

9. The control method according to claim 6, characterized in that: The third PID temperature controller and the second fan or the third fan are used to supplement the insufficient amount of combustion air input into the spray tower drying furnace through the second air flow duct, thereby controlling the flue gas temperature after the fuel in the spray tower drying furnace is burned, so that the flue gas temperature meets the slurry drying requirements in the spray tower.

10. The control method according to claim 6, characterized in that: The fourth PID controller and the exhaust fan are used to control the pressure in the spray tower drying furnace to maintain negative pressure combustion in the spray tower drying furnace, ensure that the smoke and heat in the spray tower drying furnace do not overflow, and discharge the wet smoke in the spray drying tower in time.

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