A waste gas treatment system and method for a rotary kiln for recycling and calcining waste lithium batteries

Abstract

The application discloses a waste gas treatment system and method of a rotary kiln for waste lithium battery recycling calcination, the waste gas treatment system comprises dry defluorination devices, incineration devices, denitration devices, alkali liquor spraying devices and water purification treatment devices which are sequentially connected, when the waste gas treatment system performs incineration treatment on waste gas, by correlating the incineration purification rate with the waste gas temperature, it can be realized that whether the preset incineration purification rate is reached is evaluated by detecting the waste gas temperature, and by establishing the relationship between the heating power of the incineration device and the target temperature value of waste gas heating, the heating power of the incineration device is controlled, so that the heating power of incineration can be accurately controlled, and then the waste gas can be effectively prevented from being incinerated at too high a temperature by the incineration device.

Description

Technical Field

[0001] The present invention relates to the technical field of waste lithium battery recycling, and in particular to an exhaust gas treatment system and method of a rotary kiln for recycling and calcining waste lithium batteries. Background Art

[0002] With the widespread use of lithium-ion batteries in electric vehicles, portable electronic devices, and other applications, the recycling and disposal of waste lithium-ion batteries has become an increasingly important environmental and resource recovery issue. The recycling process typically involves multiple steps to extract valuable materials and process hazardous substances to minimize environmental pollution.

[0003] The recycling process for spent lithium batteries requires a rotary kiln for calcining, effectively decomposing and removing organic components from the batteries. A key piece of equipment for high-temperature material processing, the rotary kiln's primary feature is its ability to continuously and uniformly process materials at high temperatures. With its simple structure, easy operation, and high thermal efficiency, the rotary kiln is widely used in industries such as cement, metallurgy, chemicals, and environmental protection.

[0004] During the recycling and calcination of waste lithium batteries in a rotary kiln, waste gases including fluorides, sulfur oxides, nitrogen oxides and other harmful gases will be generated. If these waste gases are not effectively treated, they will not only pollute the environment, but also endanger the health of operators. Therefore, the treatment of waste gases is particularly necessary. At present, the waste gases generated during the recycling and calcination of waste lithium batteries are usually treated in the following five steps: dry defluorination → incineration → denitrification → alkali spraying → water purification treatment. Each step uses a corresponding device to treat the waste gas, such as using a dry defluorination device, an incineration device, a denitrification device, an alkali spraying device, and a water purification treatment device to treat the waste gas, as shown in the attached figure. Figure 1 As shown, the exhaust gas can be treated to meet the emission standards before being discharged, thus not endangering the health of the workers and not polluting the environment.

[0005] However, in the prior art, during the dry defluorination treatment process of the waste gas by the dry defluorination device, due to the lack of effective evaluation and prediction of the service life of the defluorination medium and timely reminders, the staff are unable to replace the defluorination medium in time, thereby affecting the working efficiency of the dry defluorination device and increasing costs; at the same time, since the waste gas to be treated is not preheated to a corresponding appropriate temperature before being input into the dry defluorination device for treatment, the efficiency of the dry defluorination device is low during treatment.

[0006] In addition, when the incineration device is incinerating the waste gas, in order to achieve a certain incineration purification rate and ensure the purification effect of the incineration, the incineration temperature of the incineration device will be increased as much as possible to burn the harmful substances in the waste gas at high temperature for a sufficient time, so as to decompose the harmful organic substances in the waste gas as much as possible and ensure that the preset incineration purification effect is achieved. In order to detect whether the incineration device has achieved the preset incineration purification rate, it needs corresponding detection sensors to detect the exhaust gas components and adjust the heating power of the incineration device accordingly to avoid the waste of combustion and excessive combustion costs caused by excessively high temperature combustion of the waste gas. However, by regulating the heating power of the incineration device in this way, the control system is relatively complex and its maintenance cost is high.

[0007] In view of this, it is necessary to optimize and improve the waste gas treatment scheme generated during the existing recycling and calcination process of waste lithium batteries. Summary of the Invention

[0008] The purpose of the present invention is to provide an exhaust gas treatment system and method for a rotary kiln for recycling and calcining waste lithium batteries to solve at least one technical problem existing in the prior art.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] In a first aspect, the present invention provides an exhaust gas treatment system for a rotary kiln used for recycling and calcining waste lithium batteries, the exhaust gas treatment system comprising a dry defluorination device, an incineration device, a denitration device, an alkali solution spraying device, and a water purification device connected in sequence, and a main control system for controlling the working states of the dry defluorination device, the incineration device, the denitration device, the alkali solution spraying device, and the water treatment device, characterized in that:

[0011] The main control system includes an exhaust gas treatment system main control module, a dry defluorination device control module, an incineration device control module, a denitrification device control module, an alkali solution spraying device control module, and a water purification device control module respectively connected to the exhaust gas treatment system main control module;

[0012] The incineration device control module includes:

[0013] Incineration main control module;

[0014] a second detection module connected to the incineration main control module, configured to detect and obtain the flow rate S2 and temperature T2 of the exhaust gas in the incineration device, and transmit the detected flow rate S2 and temperature T2 to the incineration main control module;

[0015] a second valve control module connected to the incineration main control module, for controlling the on / off state of the second valve module, the second valve module being used as a switch for allowing the waste gas to be treated to enter the incineration device for treatment, and as a switch for discharging the waste gas in the incineration device;

[0016] A heating power control module, connected to the incineration main control module, for controlling the heating power of the incineration device;

[0017] Wherein, the heating power control module is based on the formula P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incinerator, where k is a constant, T 2初始温度 is the initial temperature of the exhaust gas entering the incineration device, T 2目标温度 The target temperature value for the incineration device to heat the exhaust gas at high temperature.

[0018] Preferably, the target temperature value T 2目标温度 The target incineration purification rate PE to be achieved by the incineration device 2达标 The target temperature value T is obtained by the following method: 2目标温度 :

[0019] Establishing an incineration purification rate database that corresponds to the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2, and establishing a relationship PE2[n]=f2(T2[n]) based on the relationship between the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2;

[0020] Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature;

[0021] According to the curve law of the curve diagram, the relationship PE2 [n] = f2 (T2 [n]) is fitted using the fitting form of the logarithmic function to obtain the relationship PE2 [n] = alog b T2[n]+c;

[0022] Let n 2S To achieve the target incineration purification rate PE 2达标 The lowest temperature value, n 2L To achieve the target incineration purification rate PE 达标 The maximum temperature value is selected in the range of n as [n 2S ,n 2L 】, the data is fitted using the logarithmic function, and the relationship PE2

n

[0023] Preferably, the dry defluorination device control module includes:

[0024] Dry defluorination main control module,

[0025] a first detection module connected to the dry defluorination main control module, for detecting and obtaining the flow rate S1 and HF concentration Q1 of the exhaust gas in the dry defluorination device, and transmitting the detected flow rate S1 and HF concentration Q1 to the dry defluorination main control module;

[0026] a first valve control module connected to the dry defluorination main control module, for controlling the on / off state of the first valve module, the first valve module being used as a switch for allowing the waste gas to be treated to enter the dry defluorination device for treatment, and as a switch for discharging the waste gas in the dry defluorination device;

[0027] A defluorination medium replacement reminder module is connected to the dry defluorination main control module and is used to send a reminder signal to replace the defluorination medium;

[0028] The dry defluorination main control module records the total fluoride load W according to the formula W=∑S1*Q1, wherein the parameter S1 is the flow rate of the exhaust gas in the dry defluorination device, and the parameter Q1 is the HF concentration of the exhaust gas in the dry defluorination device; when the dry defluorination main control module determines that the total fluoride load W is greater than or equal to the preset value A, the dry defluorination main control module outputs a corresponding control signal to control the defluorination medium replacement reminder module to issue the reminder signal.

[0029] Preferably, the denitration device control module includes:

[0030] Denitrification main control module;

[0031] a third detection module, connected to the denitration main control module, for detecting and obtaining one or more parameters of the exhaust gas in the denitration device, including temperature, flow, pressure or NOx concentration, and transmitting the detected parameters to the denitration main control module;

[0032] a third valve control module connected to the denitration main control module, for controlling the on / off state of the third valve module, the third valve module being used as a switch for allowing the waste gas to be treated to enter the denitration device for treatment, and as a switch for discharging the waste gas in the denitration device;

[0033] The alkali solution spraying device control module includes:

[0034] Alkali solution spraying main control module;

[0035] a fourth detection module, connected to the alkali solution spray main control module, for detecting and obtaining one or more parameters of the exhaust gas in the alkali solution spray device, including temperature, flow rate, air pressure or acid gas concentration, and transmitting the detected parameters to the alkali solution spray main control module;

[0036] a fourth valve control module connected to the alkali solution spray main control module, for controlling the on / off state of the fourth valve module, the fourth valve module being used as a switch for allowing the waste gas to be treated to enter the alkali solution spray device for treatment, and as a switch for discharging the waste gas or liquid in the alkali solution spray device;

[0037] The water purification device control module includes:

[0038] Water purification processing main control module;

[0039] a fifth detection module, connected to the water purification treatment main control module, for detecting and obtaining one or more parameters of the temperature, flow rate, TDS or solid impurities of the liquid in the water purification treatment device, and transmitting the detected parameters to the water purification treatment main control module;

[0040] The fifth valve control module is connected to the water purification treatment main control module and is used to control the switching state of the fifth valve module. The fifth valve module is used as a switch for the wastewater to be treated to enter the water purification treatment device for treatment, and is used as a switch for discharging the liquid in the water purification treatment device.

[0041] Preferably, the first detection module includes an HF concentration detection module, a flow detection module and a temperature detection module connected to the dry defluorination main control module;

[0042] The second detection module includes a VOCs concentration detection module, a NOx concentration detection module, an air pressure detection module, a flow detection module and a temperature detection module connected to the incineration main control module.

[0043] In a second aspect, the present invention further provides a method for treating waste gas from a rotary kiln for recycling and calcining waste lithium batteries, which is applied to a waste gas treatment system, wherein the waste gas treatment system comprises a dry defluorination device, an incineration device, a denitrification device, an alkali solution spraying device, and a water purification device connected in sequence. The waste gas treatment method comprises:

[0044] Step S10, dry defluorination: the waste gas to be treated is input into a dry defluorination device for dry defluorination treatment to remove fluoride in the waste gas;

[0045] Step S20, incineration: the waste gas after the dry defluorination step is fed into the incineration device for incineration treatment to decompose and oxidize harmful organic matter and volatile organic compounds in the waste gas at high temperature;

[0046] Step S30, denitration: the waste gas treated in the incineration step is input into the denitration device for denitration treatment to remove nitrogen oxides in the waste gas;

[0047] Step S40, alkali solution spraying: The waste gas treated in the denitrification step is input into the alkali solution spraying device for alkali solution spraying treatment to neutralize the acidic gas in the waste gas, prevent the acidic substances from polluting the environment, and ensure that the waste gas treated by the alkali solution spraying meets the emission standards before being discharged;

[0048] Step S50, water purification: purifying the wastewater generated by the alkali solution spraying treatment to ensure that the purified wastewater meets the discharge standards before being discharged;

[0049] The step S10 further includes:

[0050] Control the exhaust gas temperature at the preset target temperature value T 1目标温度 The target temperature value T is then input into the dry defluorination device. 1目标温度 The value range of is obtained according to the following method:

[0051] Establishing a defluorination purification rate database that corresponds to the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1, and establishing a relationship PE1 [n] = f1 (T1 [n]) based on the relationship between the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1;

[0052] Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature;

[0053] According to the curve law of the curve diagram, the data is fitted using the polynomial fitting form to obtain the relationship PE1 [n] = K1 * T1 [n] 2 +K2*T1

n

[0054] Let n 1S To achieve the target defluorination purification rate PE 1达标 The lowest temperature value, n 1L To achieve the target defluorination purification rate PE 1达标 The maximum temperature value; the value range of n is selected as [n 1S ,n 1L】, use the polynomial fitting form to fit the data and get the relationship PE1

n

n

n

[0055] Preferably, the step S10 further includes:

[0056] The temperature of the exhaust gas input into the dry defluorination device is detected. When it is detected that the temperature of the exhaust gas input into the dry defluorination device is not within the preset target temperature value T 1目标温度 When the temperature is within the range of the target temperature, the corresponding reminder signal is output so that the staff can control the waste gas to be treated within the preset target temperature value T in time. 1目标温度 The value is then input into the dry defluorination device for treatment within the range of .

[0057] Preferably, the step S10 further includes:

[0058] In step S10, during the dry defluorination treatment of the exhaust gas, when the dry defluorination device detects that the total fluoride load W is greater than or equal to the preset value A, the dry defluorination device sends a reminder signal for replacing the defluorination medium to remind the staff to replace the defluorination medium in time;

[0059] The dry defluorination device records the total fluoride load W according to the formula W=∑S1*Q1, wherein the parameter S1 is the flow rate of the exhaust gas in the dry defluorination device, and the parameter Q1 is the HF concentration of the exhaust gas in the dry defluorination device.

[0060] Preferably, in step S20, during the incineration process of the waste gas, the heating power control module of the incineration device controls the heating power of the incineration device according to the formula P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incinerator, where k is a constant, T 2初始温度 is the initial temperature of the exhaust gas entering the incineration device, T 2目标温度 The target temperature value for the incineration device to heat the exhaust gas at high temperature.

[0061] Preferably, the target temperature value T 2目标温度 The target incineration purification rate PE to be achieved by the incineration device 2达标 The target temperature value T is obtained by the following method: 2目标温度 :

[0062] Establishing an incineration purification rate database that corresponds to the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2, and establishing a relationship PE2[n]=f2(T2[n]) based on the relationship between the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2;

[0063] Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature;

[0064] According to the curve law of the curve diagram, the relationship PE2 [n] = f2 (T2 [n]) is fitted using the fitting form of the logarithmic function to obtain the relationship PE2 [n] = alog b T2[n]+c;

[0065] Let n 2S To achieve the target incineration purification rate PE 2达标 The lowest temperature value, n 2L To achieve the target incineration purification rate PE 达标 The maximum temperature value is selected in the range of n as [n 2S ,n 2L 】, the data is fitted using the logarithmic function, and the relationship PE2

n

[0066] Compared with the prior art, the beneficial effects of the present invention include at least:

[0067] (1) When the waste gas is subjected to dry defluorination treatment, the present invention records the total fluoride load W of the dry defluorination device and determines whether the total fluoride load W reaches or approaches the total defluorination load of the defluorination medium. If so, a corresponding control signal is issued to cause the defluorination medium replacement reminder module to issue a reminder signal to remind the staff to replace the defluorination medium in time, thereby effectively improving the working efficiency of the dry defluorination device;

[0068] (2) When the present invention performs dry defluorination treatment on the waste gas, it establishes a defluorination purification rate database corresponding to the defluorination purification rate PE1 of the dry defluorination device and the waste gas temperature T1, and finally obtains the relationship between the defluorination purification rate PE1 that the dry defluorination device needs to achieve and the input waste gas temperature T1 based on the relationship between the defluorination purification rate PE1 and the waste gas temperature T1, so that the waste gas temperature can be controlled at the preset target temperature value T 1目标温度 Within the value range of , the defluorination treatment of the waste gas in the dry defluorination device can be made more efficient;

[0069] (3) When the present invention incinerates the waste gas, an incineration purification rate database is established to show the corresponding relationship between the incineration purification rate PE2 of the incineration device and the waste gas temperature T2, and the relationship between the incineration purification rate PE2 and the waste gas temperature T2 is calculated according to the relationship between the incineration purification rate PE2 [n] = alog b T2[n]+c, thus associating the incineration purification rate PE2 with the exhaust gas temperature T2, and then using the exhaust gas temperature to evaluate whether the preset incineration purification rate has been achieved, which has the advantages of low maintenance cost and strong operability, and also by establishing the heating power P of the incineration device 加热 The target temperature value T that the exhaust gas needs to be heated 2目标温度 The relationship P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incineration device, so as to achieve precise control of the heating power of incineration, and thus effectively avoid the incineration device from incinerating the waste gas at too high a temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 A schematic diagram of the structure of an exhaust gas treatment system for treating exhaust gas from a rotary kiln used for recycling and calcining waste lithium batteries in the prior art;

[0071] Figure 2 This is a schematic block diagram of the circuit structure of the main control system of the exhaust gas treatment system according to Example 1 of the present invention;

[0072] Figure 3 This is a schematic block diagram of the circuit structure of the dry defluorination main control module described in Example 1 of the present invention;

[0073] Figure 4 This is a schematic block diagram of the circuit structure of the incineration main control module described in Example 1 of the present invention;

[0074] Figure 5 This is a schematic block diagram of the circuit structure of the denitration main control module described in Example 1 of the present invention;

[0075] Figure 6This is a schematic block diagram of the circuit structure of the alkali solution spraying main control module described in Example 1 of the present invention;

[0076] Figure 7 This is a schematic block diagram of the circuit structure of the water purification main control module described in Example 1 of the present invention;

[0077] Figure 8 This is a schematic diagram of the method flow of the waste gas treatment method according to Example 2 of the present invention;

[0078] Figure 9 Schematic diagram of a curve showing the exhaust gas temperature values ​​and their corresponding defluorination purification rate values ​​obtained by sampling data in the defluorination purification rate database in Example 2 of the present invention;

[0079] Figure 10 For the general Figure 9 The data in the figure are sorted in ascending order according to the exhaust gas temperature value, and the curve diagram of the relationship between the defluorination purification rate and the exhaust gas temperature is obtained after reorganization;

[0080] Figure 11 For attachment Figure 10 Simplified schematic diagram of data fitting to the data in .

[0081] Figure 12 In order to select the effective exhaust gas temperature value [n 1S ,n 1L 】(90℃≤n≤132℃) for the relationship PE1

n

n

n

[0082] Figure 13 A schematic diagram of a curve showing exhaust gas temperature values ​​and corresponding incineration purification rate values ​​obtained by sampling data in the incineration purification rate database in Example 2 of the present invention;

[0083] Figure 14 For the general Figure 13 The data is sorted in ascending order according to the exhaust gas temperature value, and the curve diagram of the relationship between the incineration purification rate and the exhaust gas temperature is obtained after reorganization;

[0084] Figure 15 For attachment Figure 14 Simplified schematic diagram of data fitting to the data in .

[0085] Figure 16 After selecting the effective exhaust gas temperature value [740℃,∞], the relationship PE2 [n] = alog b Schematic diagram of the curve obtained by data fitting of T2[n]+c;

[0086] Figure 17This is a schematic diagram of the device structure of the exhaust gas treatment system described in Example 3 of the present invention. DETAILED DESCRIPTION

[0087] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0088] Example 1

[0089] Embodiment 1 of the present invention provides an exhaust gas treatment system for a rotary kiln used for recycling and calcining waste lithium batteries, the exhaust gas treatment system comprising a dry defluorination device, an incineration device, a denitration device, an alkali solution spraying device, and a water purification device connected in sequence, and a main control system for controlling the working states of the dry defluorination device, the incineration device, the denitration device, the alkali solution spraying device, and the water treatment device;

[0090] The waste gas treatment system is used to treat waste gas generated when the rotary kiln is used to recycle and calcine waste lithium batteries. These waste gases include hydrofluoric acid (HF), volatile organic compounds (VOCs), nitrogen oxides (NOx), hydrogen chloride (HCL), sulfur dioxide (SO2), hydrogen sulfide (H2S) and other harmful gases;

[0091] The dry defluorination device is used to defluorinate waste gas, and is mainly used to remove fluoride from the waste gas. This is because waste lithium batteries may contain fluoride, which will be converted into gaseous hydrogen fluoride (HF) during the calcination process. In the dry defluorination device, a defluorination medium (adsorbent) such as limestone, calcium hydroxide (Ca(OH)2) or activated alumina is usually used to adsorb and neutralize hydrogen fluoride (HF) in the waste gas. After defluorination treatment by the dry defluorination device, the fluoride concentration in the gas is significantly reduced, and it can enter the incineration device for treatment;

[0092] The incineration device is used to further treat organic matter and other combustible substances in the waste gas. During the calcination of waste lithium batteries, some organic volatile substances (VOCs) or other harmful gases may be generated. The incineration device is used to burn these gases at high temperatures to decompose the harmful components and convert them into relatively harmless carbon dioxide, water vapor and other simple gases.

[0093] The denitrification device is mainly used to remove nitrogen oxides (NOx) from the exhaust gas. Nitrogen oxides are typical pollutants produced during the calcination process and can cause acid rain and air pollution. The denitrification device can reduce NOx to nitrogen (N2) and water through technologies such as selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR), thereby reducing the emission of nitrogen oxides.

[0094] The alkali solution spraying device is mainly used to neutralize acidic gases in the exhaust gas, such as hydrogen chloride (HCl), sulfur dioxide (SO2), hydrogen sulfide (H2S) and other acidic gases. The alkali solution spraying device sprays an alkaline solution (such as sodium hydroxide solution or calcium hydroxide slurry) into the exhaust gas flow to react with the acidic gas to form soluble salts, thereby reducing the concentration of acidic pollutants;

[0095] The water purification treatment device is mainly used to treat the wastewater generated by the alkali solution spraying device and other waste liquids generated during the exhaust gas purification process. These wastewater and waste liquids may contain solid impurities, soluble harmful substances, heavy metals, etc., and need to be purified through precipitation, filtration, neutralization and other processes to ensure that the discharged wastewater meets environmental protection standards.

[0096] The exhaust gas is comprehensively treated in sequence through a dry defluorination device, an incineration device, a denitrification device, an alkali spray device, and a water purification device, which can gradually remove harmful components in the exhaust gas and thus meet environmental emission standards.

[0097] In the embodiment of the present invention, it mainly optimizes and improves the main control system for controlling the working status of the dry defluorination device, the incineration device, the denitrification device, the alkali liquid spraying device, and the water treatment device in the exhaust gas treatment system, and does not involve the mechanical structure of the treatment devices such as the dry defluorination device, the incineration device, the denitrification device, the alkali liquid spraying device, and the water purification treatment device. The specific working principles of these devices belong to the prior art. Those skilled in the art can select the corresponding devices and equipment in the prior art as needed to implement them. For example, the dry defluorination device can use a dry scrubber (vertical flow packed bed adsorption device), the incineration device can use an incinerator, the denitrification device can use a selective catalytic reduction (SCR) device or a selective non-catalytic reduction (SNCR) device, the alkali liquid spraying device can use a spray tower, and the water purification treatment device can use a sedimentation tank with chemical precipitation and filtration functions. Therefore, the specific composition of the mechanical structure of these devices will not be described in detail here.

[0098] The following is a further detailed description of the optimized and improved main control system in the solution of the present invention:

[0099] As attached Figure 2 - Figure 7As shown, the main control system includes a waste gas treatment system main control module, a dry defluorination device control module, an incineration device control module, a denitrification device control module, an alkali solution spraying device control module, and a water purification device control module respectively connected to the waste gas treatment system main control module; wherein, the present invention mainly relates to optimizing and improving the dry defluorination device control module and the incineration device control module in the main control system, which are described in detail below.

[0100] As attached Figure 4 As shown, the incineration device control module includes:

[0101] Incineration main control module;

[0102] A second detection module is connected to the incineration main control module, and is used to detect and obtain the flow rate S2 and temperature T2 of the exhaust gas in the incineration device, and transmit the detected flow rate S2 and temperature T2 to the incineration main control module; preferably, the second detection module includes a VOCs concentration detection module, a NOx concentration detection module, an air pressure detection module, a flow detection module and a temperature detection module connected to the incineration main control module, wherein the VOCs concentration detection module, the NOx concentration detection module and the air pressure detection module are respectively used to detect the VOCs concentration, NOx concentration and air pressure of the exhaust gas in the incineration device, the flow detection module is used to detect the flow rate S2, and the temperature detection module is used to detect the temperature T2;

[0103] a second valve control module connected to the incineration main control module, for controlling the on / off state of the second valve module, the second valve module being used as a switch for allowing the waste gas to be treated to enter the incineration device for treatment, and as a switch for discharging the waste gas in the incineration device;

[0104] A heating power control module, connected to the incineration main control module, for controlling the heating power of the incineration device;

[0105] Wherein, the heating power control module is based on the formula P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incinerator, where k is a constant, T 2初始温度 is the initial temperature of the exhaust gas entering the incineration device, T 2目标温度 The target temperature value for the incineration device to heat the exhaust gas at high temperature.

[0106] In the solution of the present invention, the target temperature value T 2目标温度 The target incineration purification rate PE to be achieved by the incineration device 2达标 The target temperature value T can be obtained by the following method: 2目标温度 :

[0107] Establishing an incineration purification rate database that corresponds to the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2, and establishing a relationship PE2[n]=f2(T2[n]) based on the relationship between the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2;

[0108] Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature;

[0109] According to the curve law of the curve diagram, the relationship PE2 [n] = f2 (T2 [n]) is fitted using the fitting form of the logarithmic function to obtain the relationship PE2 [n] = alog b T2[n]+c;

[0110] Let n 2S To achieve the target incineration purification rate PE 2达标 The lowest temperature value, n 2L To achieve the target incineration purification rate PE 达标 The maximum temperature value is selected in the range of n as [n 2S ,n 2L 】, the data is fitted using the logarithmic function, and the relationship PE2

n

[0111] In the embodiment of the present invention, a database of the incineration purification rate PE2 and the exhaust gas temperature T2 of the incineration device is established, and a corresponding relationship PE2[n]=f2(T2[n]) is established between the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2, thereby associating the incineration purification rate PE2 with the exhaust gas temperature T2. Then, a curve diagram of the relationship between the incineration purification rate and the exhaust gas temperature T2 is drawn by collecting data from the incineration purification rate database and sorting the temperature values ​​from small to large. Then, according to the curve law of the curve diagram, the fitting form of the logarithmic function is selected to perform data fitting on the relationship PE2[n]=f2(T2[n]), and the relationship PE2[n]=alog b T2[n]+c, and finally the least square method is used to fit the data to obtain the corresponding values ​​of a, b, and c, thereby finally obtaining the target temperature value T 2目标温度 .

[0112] In the prior art, in order to detect whether the incineration device has reached the preset incineration purification rate, it is necessary to use corresponding detection sensors to detect the exhaust gas components to confirm and adjust the heating power of the incineration device accordingly to avoid combustion waste and excessive combustion costs caused by high-temperature combustion. However, by regulating the heating power of the incineration device in this way, the control system is relatively complex, the control accuracy is not high, and its maintenance cost is high.

[0113] In the embodiment of the present invention, the incineration purification rate PE2 is associated with the exhaust gas temperature T2, and the exhaust gas temperature can be detected to evaluate whether the preset incineration purification rate is reached. Since temperature detection is highly mature and has low maintenance costs, compared with directly detecting the incineration purification rate of the exhaust gas treated by the incineration device through the corresponding exhaust gas component detection sensor, its maintenance cost is much higher. Therefore, compared with the existing technology, the scheme of the present invention has very considerable economy and operability after promotion and implementation, especially after promotion and application, its cost will be greatly reduced.

[0114] Furthermore, in the embodiment of the present invention, the heating power P of the incineration device is established. 加热 The target temperature value T that the exhaust gas needs to be heated 2目标温度 Establish the relationship P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incineration device, which can accurately control the heating power of the incineration, thereby effectively heating the exhaust gas to the required temperature value, and effectively avoiding the incineration device from incinerating the exhaust gas at too high a temperature.

[0115] It should be noted that the hardware components of the incineration main control module can be implemented using existing technologies, and the second valve control module, the heating power control module, the VOCs concentration detection module, the NOx concentration detection module, the air pressure detection module, the flow detection module, and the temperature detection module in the second detection module can all be implemented using existing technologies. For example, the NOx concentration detection module can utilize an electrochemical sensor, a non-dispersive infrared (NDIR) sensor, or a differential absorption spectroscopy (DOAS) sensor that are well-established in the existing technologies; the flow detection module can utilize a thermal mass flow sensor or a differential pressure flow sensor that are well-established in the existing technologies; and the temperature detection module can utilize a thermocouple or an infrared temperature sensor that are well-established in the existing technologies. The specific composition and working principles of the above functional modules will not be described in detail here.

[0116] In one preferred embodiment, the dry defluorination device control module is as shown in the attached Figure 3 As shown, it includes:

[0117] Dry defluorination main control module,

[0118] A first detection module is connected to the dry defluorination main control module, and is used to detect and obtain the flow rate S1 and HF concentration Q1 of the exhaust gas in the dry defluorination device, and transmit the detected flow rate S1 and HF concentration Q1 to the dry defluorination main control module; specifically, the first detection module includes an HF concentration detection module, a flow detection module, and a temperature detection module connected to the dry defluorination main control module; wherein, the HF concentration detection module is used to detect the HF concentration Q1 of the exhaust gas in the dry defluorination device, the flow detection module is used to detect the flow rate S1 of the exhaust gas in the dry defluorination device, and the temperature detection module is used to detect the temperature of the exhaust gas in the dry defluorination device;

[0119] a first valve control module connected to the dry defluorination main control module, for controlling the on / off state of the first valve module, the first valve module being used as a switch for allowing the waste gas to be treated to enter the dry defluorination device for treatment, and as a switch for discharging the waste gas in the dry defluorination device;

[0120] A defluorination medium replacement reminder module is connected to the dry defluorination main control module and is used to send a reminder signal to replace the defluorination medium;

[0121] The dry defluorination main control module records the total fluoride load W according to the formula W = ∑S1*Q1, wherein the parameter S1 is the flow rate of the exhaust gas in the dry defluorination device, and the parameter Q1 is the HF concentration of the exhaust gas in the dry defluorination device; when the dry defluorination main control module determines that the total fluoride load W is greater than or equal to the preset value A, the dry defluorination main control module outputs a corresponding control signal to control the defluorination medium replacement reminder module to issue the reminder signal. Specifically, in the formula W = ∑S1*Q1, W is the sum of the products of the flow rate S1 of the exhaust gas in the dry defluorination device and the HF concentration Q1, which represents the total fluoride load W in the dry defluorination device. After the defluorination medium is replaced, the dry defluorination main control module re-records the total fluoride load W according to the formula W = ∑S1*Q1.

[0122] When the dry defluorination device performs dry defluorination treatment on the exhaust gas, a defluorination medium (such as limestone, calcium hydroxide (Ca(OH)2) or activated alumina) is usually used to adsorb or remove fluorides in the exhaust gas. Assuming that the total defluorination load of the defluorination medium (the total load of adsorbed or removed fluorides) is B, the preset value A is equal to or slightly less than the total defluorination load B. In actual application, A is slightly less than B, so that when the defluorination medium is about to reach its maximum total defluorination load, the defluorination medium replacement reminder module can promptly issue the reminder signal. In a specific embodiment, the defluorination medium replacement reminder module can be a sound reminder module and / or a light reminder module, so the reminder signal can be a sound reminder signal and / or a light reminder signal.

[0123] In the embodiment of the present invention, the dry defluorination main control module records the total fluoride load W of the dry defluorination device and determines whether the total fluoride load W reaches or is close to the total defluorination load of the defluorination medium. If so, a corresponding control signal is issued to enable the defluorination medium replacement reminder module to issue a reminder signal to remind the staff to replace the defluorination medium in time, thereby effectively improving the working efficiency of the dry defluorination device.

[0124] It should be noted that the hardware part of the dry defluorination main control module can be implemented by existing technology, and the first valve control module, the HF concentration detection module, the flow detection module and the temperature detection module in the first detection module can all be implemented by corresponding sensors in the existing technology. For example, the HF concentration detection module can use an electrochemical sensor or an infrared spectrum sensor that is mature in the existing technology, the flow detection module can use a thermal mass flow sensor or a differential pressure flow sensor that is mature in the existing technology, and the temperature detection module can use a thermocouple or an infrared temperature sensor that is mature in the existing technology. The specific composition and working principle of the above functional modules will not be described in detail here.

[0125] In the embodiment of the present invention, there is no optimization or improvement of the denitrification device control module, the alkali solution spraying device control module, and the water purification treatment device control module in the main control system. Those skilled in the art can select corresponding functional modules as needed. The following describes a more preferred implementation of each functional module of the denitrification device control module, the alkali solution spraying device control module, and the water purification treatment device control module.

[0126] In one specific embodiment, the denitrification device control module is as shown in the attached Figure 5 As shown, it includes:

[0127] Denitrification main control module;

[0128] a third detection module connected to the denitration main control module, configured to detect and obtain one or more parameters of the exhaust gas in the denitration device, including temperature, flow rate, air pressure, or NOx concentration, and transmit the detected parameters to the denitration main control module; specifically, the third detection module includes one or more detection modules selected from the group consisting of a temperature detection module, a flow rate detection module, an air pressure detection module, and a NOx concentration detection module;

[0129] The third valve control module is connected to the denitrification main control module and is used to control the switching state of the third valve module. The third valve module is used as a switch for the waste gas to be treated to enter the denitrification device for treatment, and is used as a switch for discharging the waste gas in the denitrification device.

[0130] In one specific embodiment, the alkali solution spraying device control module is as shown in the attached Figure 6 Shown, including:

[0131] Alkali solution spraying main control module;

[0132] a fourth detection module connected to the alkali liquid spray main control module, configured to detect and obtain one or more parameters of the exhaust gas in the alkali liquid spray device, including temperature, flow rate, air pressure, or acid gas concentration, and transmit the detected parameters to the alkali liquid spray main control module; specifically, the fourth detection module includes one or more detection modules selected from the group consisting of a temperature detection module, a flow rate detection module, an air pressure detection module, and an acid gas concentration detection module;

[0133] The fourth valve control module is connected to the alkali solution spray main control module and is used to control the switching state of the fourth valve module. The fourth valve module is used as a switch for the waste gas to be treated to enter the alkali solution spray device for treatment, and is used as a switch for discharging the waste gas or liquid in the alkali solution spray device.

[0134] In one specific embodiment, the water purification device control module is as shown in the attached Figure 7As shown, it includes:

[0135] Water purification processing main control module;

[0136] a fifth detection module connected to the water purification treatment main control module, configured to detect and obtain one or more parameters of the temperature, flow rate, TDS or solid impurities of the liquid in the water purification treatment device, and transmit the detected parameters to the water purification treatment main control module; specifically, the fifth detection module includes one or more detection modules selected from the group consisting of a temperature detection module, a flow rate detection module, a TDS detection module and a solid impurity detection module;

[0137] The fifth valve control module is connected to the water purification treatment main control module and is used to control the switching state of the fifth valve module. The fifth valve module is used as a switch for the wastewater to be treated to enter the water purification treatment device for treatment, and is used as a switch for discharging the liquid in the water purification treatment device.

[0138] It should be noted that the embodiments of the present invention do not involve optimization and improvement of the denitrification main control module, the alkali solution spray device control module, and the water purification treatment device control module. Those skilled in the art may select corresponding functional modules in the prior art according to actual needs, such as the detection modules in the third detection module, the fourth detection function module, and the fifth detection function module, and may select corresponding sensors in the prior art for implementation. For example, the NOx concentration detection module, the flow detection module, and the temperature detection module may all be implemented by corresponding sensors in the prior art. For example, the NOx concentration detection module may be an electrochemical sensor or a non-dispersive infrared (NDIR) sensor that is well-known in the prior art. The acid gas concentration detection module may be an electrochemical sensor that is well-known in the prior art. The flow detection module may be a thermal mass flow sensor or a differential pressure flow sensor that is well-known in the prior art. The temperature detection module may be a thermocouple or an infrared temperature sensor that is well-known in the prior art. The specific composition and working principle of the denitrification main control module, the alkali solution spray device control module, and the water purification treatment device control module will not be described in detail here.

[0139] The working principle or working process of the exhaust gas treatment system described in the embodiment of the present invention will be further explained in Example 2.

[0140] Example 2

[0141] This embodiment 2 provides a waste gas treatment method for a rotary kiln used for recycling and calcining waste lithium batteries, which is applied to a waste gas treatment system. The waste gas treatment system includes a dry defluorination device, an incineration device, a denitrification device, an alkali solution spraying device, and a water purification device connected in sequence, as shown in the attached figure. Figure 8As shown, the exhaust gas treatment method includes:

[0142] Step S10, dry defluorination: the waste gas to be treated is input into a dry defluorination device for dry defluorination treatment to remove fluoride in the waste gas;

[0143] Step S20, incineration: the waste gas after the dry defluorination step is fed into the incineration device for incineration treatment to decompose and oxidize harmful organic matter and volatile organic compounds in the waste gas at high temperature;

[0144] Step S30, denitration: the waste gas treated in the incineration step is input into the denitration device for denitration treatment to remove nitrogen oxides in the waste gas;

[0145] Step S40, alkali solution spraying: The waste gas treated in the denitrification step is input into the alkali solution spraying device for alkali solution spraying treatment to neutralize the acidic gas in the waste gas, prevent the acidic substances from polluting the environment, and ensure that the waste gas treated by the alkali solution spraying meets the emission standards before being discharged;

[0146] Step S50, water purification treatment: purifying the wastewater generated by the alkali solution spraying treatment to ensure that the purified wastewater meets the discharge standards before being discharged.

[0147] In Example 2 of the present invention, the optimization and improvement of steps S10 to S20 are mainly carried out, and the optimization and improvement of steps S30 to S50 are not involved. Therefore, steps S30 to S50 belong to the prior art and are not described in detail here. The following is a further detailed description of the optimized and improved steps S10 to S20 in Example 2 of the present invention.

[0148] In order to improve the efficiency of dry defluorination, the present invention controls the temperature of the waste gas to be treated within a preset value range before inputting it into the dry defluorination process in the existing step S10. Specifically,

[0149] In the step S10, it further includes:

[0150] Control the exhaust gas temperature at the preset target temperature value T 1目标温度 The target temperature value T is then input into the dry defluorination device. 1目标温度 The value range of is obtained according to the following method:

[0151] Establishing a defluorination purification rate database that corresponds to the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1, and establishing a relationship PE1 [n] = f1 (T1 [n]) based on the relationship between the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1;

[0152] Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature;

[0153] According to the curve law of the curve diagram, the data is fitted using the polynomial fitting form to obtain the relationship PE1 [n] = K1 * T1 [n] 2 +K2*T1

n

[0154] Let n 1S To achieve the target defluorination purification rate PE 1达标 The lowest temperature value, n 1L To achieve the target defluorination purification rate PE 1达标 The maximum temperature value; the value range of n is selected as [n 1S ,n 1L 】, use the polynomial fitting form to fit the data and get the relationship PE1

n

n

n

n

[0155] In Example 2 of the present invention, a defluorination purification rate database of the defluorination purification rate PE1 and the exhaust gas temperature T1 of the dry defluorination device is established, and a relationship PE1 [n] = f1 (T1 [n]) is established based on the relationship between the defluorination purification rate PE1 and the exhaust gas temperature T1. Then, the exhaust gas temperature values ​​and their corresponding defluorination purification rate values ​​in the defluorination purification rate database are sampled, and the temperature values ​​are sorted from small to large to draw a curve diagram of the relationship between the defluorination purification rate and the exhaust gas temperature. According to the curve law of the curve diagram, a polynomial fitting form is selected for data fitting, thereby finally obtaining the target temperature value T 1目标温度 The range of values ​​can be used to control the temperature of the exhaust gas to the preset target temperature value T 1目标温度 Within the value range of , the defluorination treatment of waste gas in the dry defluorination device can be made more efficient.

[0156] The following is a further description of the specific implementation method: Specifically, in the dry defluorination process of step S10, by sampling data in the defluorination purification rate database, the sampled exhaust gas temperature value and its corresponding defluorination purification rate value are plotted as shown in the attached figure. Figure 9 Then, sort the temperature values ​​from small to large and draw a curve diagram of the relationship between the defluorination purification rate and the exhaust gas temperature, as shown in the attached figure. Figure 10 In the embodiment of the present invention, the defluorination purification rate PE1 of the dry defluorination device is equal to or greater than 90% as the target defluorination purification rate PE 1达标 , let n 1S To achieve the target defluorination purification rate PE 1达标 The lowest temperature value, n 1L To achieve the target defluorination purification rate PE 1达标 The maximum temperature value is given by Figure 10 It can be seen that n 1L About 90℃, n 1S About 132℃, that is, the value range of n [n 1S ,n 1L 】 is 90℃≤n≤132℃. Since the value range of n is [90℃, 132℃], according to Figure 10 The curve law of the curve diagram shown in the figure is that the data obtained by fitting the data in the form of polynomial fitting will be more accurate. Therefore, according to Figure 10 The curve law of the curve diagram shown in the figure is fitted by using the polynomial fitting form to obtain the relationship PE1[n]=K1*T1[n] 2 +K2*T1

n

[0157] When selecting an effective exhaust gas temperature value [n 1S ,n 1L 】(90℃≤n≤132℃), use the least square method to solve the above relationship PE1

n

n

n

n

n

n

[0158] In a preferred embodiment, the step S10 further includes:

[0159] The temperature of the exhaust gas input into the dry defluorination device is detected. When it is detected that the temperature of the exhaust gas input into the dry defluorination device is not within the preset target temperature value T 1目标温度 When the temperature is within the range of the target temperature, the corresponding reminder signal is output so that the staff can control the waste gas to be treated within the preset target temperature value T in time. 1目标温度 In practical application, a temperature sensor for detecting the exhaust gas temperature and a temperature display device for displaying the exhaust gas temperature can be provided near the exhaust gas inlet of the dry defluorination device.

[0160] By detecting the temperature of the waste gas to be treated and judging whether the temperature of the waste gas is within the preset target temperature value T 1目标温度 If the exhaust gas temperature is not within the preset target temperature T 1目标温度 If the temperature of the exhaust gas is within the preset target temperature value T 1目标温度 Then it is input into the dry defluorination device for defluorination.

[0161] Specifically, the target defluorination purification rate PE of the dry defluorination device is 1达标 The exhaust gas temperature needs to be controlled between 106℃ and 115℃, which is the preset target temperature value T 1目标温度 The value range is 106℃~115℃. When it is detected that the input temperature value of the exhaust gas is not in the range of 106℃~115℃, a reminder signal is issued to enable the staff to control the exhaust gas temperature in the temperature range of 106℃~115℃ in time.

[0162] In a preferred embodiment, the step S10 further includes:

[0163] In step S10, during the dry defluorination treatment of the exhaust gas, when the dry defluorination device detects that the total fluoride load W is greater than or equal to a preset value A, the dry defluorination device sends a reminder signal for replacing the defluorination medium to remind the staff to replace the defluorination medium in time; wherein the preset value A is equal to or slightly less than the total defluorination load B, and the total defluorination load B refers to the total load of fluorides that the defluorination medium can adsorb or remove;

[0164] The dry defluorination device records the total fluoride load W according to the formula W=∑S1*Q1, wherein the parameter S1 is the flow rate of the exhaust gas in the dry defluorination device, and the parameter Q1 is the HF concentration of the exhaust gas in the dry defluorination device.

[0165] In an embodiment of the present invention, the total fluoride load W is recorded using the formula W = ∑S1 * Q1 and compared with a preset value A equal to or slightly less than the total defluorination load B. When the total fluoride load W is detected to be greater than or equal to the preset value A, the dry defluorination device issues a reminder signal to replace the defluorination medium, thereby reminding the staff to replace the defluorination medium in a timely manner. The working principle or working process of recording the total fluoride load W using the formula W = ∑S1 * Q1 and comparing it with the preset value A equal to or slightly less than the total defluorination load B can be found in Example 1 for details and will not be repeated here.

[0166] In a specific embodiment, the total defluorination load B of the defluorination medium is 200 kg, the preset value A is equal to or slightly less than 200 kg, such as the preset value A is 198 kg, and the fluoride concentration (HF concentration) Q1 in the exhaust gas is 350 mg / m 3 , the current exhaust gas flow S1 is 6000m 3 / h. Since the concentration and flow rate of the exhaust gas are a set of dynamically changing values, the total fluoride load is continuously recorded by the formula W=∑S1*Q1, and the total fluoride load W is continuously compared with the total defluorination load B. When it is detected that the total fluoride load W is equal to or greater than 198kg, the dry defluorination device sends a reminder signal to replace the defluorination medium, thereby reminding the staff to replace the defluorination medium in time.

[0167] In order to prevent the incineration device from performing excessively high-temperature combustion treatment on the waste gas, it is usually necessary to detect the incineration purification rate of the incineration process. When the detection reaches the preset incineration purification rate, the heating power of the incineration device is controlled to stop heating and incineration or reduce the heating power.

[0168] In the prior art, in the incineration process at step S20, a corresponding exhaust gas component detection sensor is provided to directly detect the exhaust gas after the incineration process to determine whether the incineration purification rate has been achieved. However, this method has the disadvantage of high cost. Therefore, in the embodiment of the present invention, the incineration purification rate is associated with the exhaust gas temperature, and the exhaust gas temperature is detected to assess whether the preset incineration purification rate has been achieved. The heating power of the incineration device is controlled by establishing a relationship between the heating power of the incineration device and the target temperature value of the exhaust gas heating, thereby achieving precise control of the heating power of the incineration, and effectively preventing the incineration device from incinerating the exhaust gas at excessively high temperatures.

[0169] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0170] The step S20 further includes:

[0171] In step S20, during the incineration process of the waste gas, the heating power control module of the incineration device controls the heating power of the incineration device according to the formula P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incinerator, where k is a constant, T 2初始温度 is the initial temperature of the exhaust gas entering the incineration device, T 2目标温度 The target temperature value for the incineration device to heat the exhaust gas at high temperature.

[0172] The k is the proportional coefficient related to [equivalent specific heat capacity of exhaust gas] * [exhaust gas density]. According to the principle of conservation of energy, the input heat is equal to the heat of exhaust gas heating plus the heat loss of the incineration device. Since the structural design of the incineration device is fixed and the energy loss accounts for a small proportion, the calculation model is simplified for the convenience of calculation to obtain the heating power P of the incineration device. 加热 * Time = Volume equivalent heat capacity of the waste gas to be treated * (gas density * gas volume flow rate * time) * (T 2初始温度 -T 2目标温度 ), thus obtaining the formula P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ), and k is a fixed value (or a constant value with very small changes); in practical applications, a k value database for the same incineration device can be established, and more data can be accumulated through the database to optimize the k value, so as to make the heating power of the incineration device more accurately controlled.

[0173] In a preferred embodiment, the target temperature value T 2目标温度 The target incineration purification rate PE to be achieved by the incineration device 2达标The target temperature value T is obtained by the following method: 2目标温度 :

[0174] Establishing an incineration purification rate database that corresponds to the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2, and establishing a relationship PE2[n]=f2(T2[n]) based on the relationship between the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2;

[0175] Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature;

[0176] According to the curve law of the curve diagram, the relationship PE2 [n] = f2 (T2 [n]) is fitted using the fitting form of the logarithmic function to obtain the relationship PE2 [n] = alog b T2[n]+c;

[0177] Let n 2S To achieve the target incineration purification rate PE 2达标 The lowest temperature value, n 2L To achieve the target incineration purification rate PE 达标 The maximum temperature value is selected in the range of n as [n 2S ,n 2L 】, the data is fitted using the logarithmic function, and the relationship PE2

n

[0178] In the embodiment of the present invention, a database of the incineration purification rate PE2 and the exhaust gas temperature T2 of the incineration device is established, and a corresponding relationship PE2 [n] = f2 (T2 [n]) is established by the relationship between the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2, thereby associating the incineration purification rate PE2 with the exhaust gas temperature T2. Then, by collecting data from the incineration purification rate database and sorting the temperature values ​​from small to large, a curve diagram of the relationship between the incineration purification rate and the exhaust gas temperature is drawn. Then, according to the curve law of the curve diagram, the fitting form of the logarithmic function is selected to perform data fitting on the relationship PE2 [n] = f2 (T2 [n], and the relationship PE2 [n] = alog bT2[n]+c, and finally the least square method is used to fit the data to obtain the corresponding values ​​of a, b, and c, thereby finally obtaining the target temperature value T 2目标温度 .

[0179] The target temperature value T is obtained 2目标温度 After that, the heating power control module of the incineration device can be controlled according to the formula P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incineration device so that the exhaust gas in the incineration device is heated to the target temperature value range, thereby achieving precise control of the heating power of the incineration, and effectively avoiding the incineration device from incinerating the exhaust gas at too high a temperature.

[0180] The target temperature value T is obtained by a specific embodiment as follows: 2目标温度 For further explanation:

[0181] In the incineration process of step S20, data is sampled in the incineration purification rate database, and a schematic diagram of the sampled exhaust gas temperature value and its corresponding incineration purification rate value is drawn, as shown in the attached figure. Figure 13 Then, sort the temperature values ​​from small to large and draw a curve diagram of the relationship between the incineration purification rate and the exhaust gas temperature, as shown in the attached figure. Figure 14 In the embodiment of the present invention, the target incineration purification rate PE2 of the incineration device is equal to or greater than 95%. 2达标 , let n 2S To achieve the target incineration purification rate PE 2达标 The lowest temperature value, n 2L To achieve the target incineration purification rate PE 2达标 The maximum temperature value is given by Figure 14 It can be seen that n 2s is about 740℃, and n 2L →∞, since the effective value range of n is [740℃,∞], according to Figure 14 The curve law of the curve diagram shown in the figure is that the data obtained by fitting the logarithmic function will be more accurate. Therefore, according to Figure 14 The curve law of the curve diagram shown in the figure is used to fit the data using the fitting form of the logarithmic function, and the relationship PE2 [n] = alog b T2[n]+c, for easy understanding, please refer to the attached Figure 15 .

[0182] After selecting the effective exhaust gas temperature value [740℃,∞], the least square method is used to solve the above relationship PE2[n]=alog b T2[n]+c is used to fit the data, and the following is obtained: Figure 16 The curve diagram shown in the figure can finally be used to obtain the relationship PE2 [n] = alog b The coefficients of T2[n]+c are a=0.0213, b=natural logarithm e, c=0.886, so that the target temperature value T can be finally obtained. 2目标温度 According to the above relationship PE2

n

[0183] Example 3

[0184] This embodiment 3 provides an exhaust gas treatment system for a rotary kiln used for recycling and calcining waste lithium batteries. The exhaust gas treatment system includes a dry defluorination device, an incineration device, a denitration device, an alkali solution spraying device, and a water purification device connected in sequence, and a main control system for controlling the working status of the dry defluorination device, the incineration device, the denitration device, the alkali solution spraying device, and the water treatment device. The optimization and improvement of the exhaust gas treatment system in the embodiment of the present invention is that the exhaust gas treatment system also includes an exhaust gas preheating treatment device, which is used to control the temperature of the exhaust gas at a preset target temperature value T 1目标温度 The target temperature value T is then input into the dry defluorination device. 1目标温度 The value range of is obtained according to the following method:

[0185] Establishing a defluorination purification rate database that corresponds to the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1, and establishing a relationship PE1 [n] = f1 (T1 [n]) based on the relationship between the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1;

[0186] Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature;

[0187] According to the curve law of the curve diagram, the data is fitted using the polynomial fitting form to obtain the relationship PE1 [n] = K1 * T1 [n] 2 +K2*T1

n

[0188] Let n 1S To achieve the target defluorination purification rate PE 1达标 The lowest temperature value, n 1L To achieve the target defluorination purification rate PE 1达标 The maximum temperature value; the value range of n is selected as [n 1S ,n 1L 】, use the polynomial fitting form to fit the data and get the relationship PE1

n

n

n

[0189] For the target temperature value T 1目标温度 The principle and process of the method for obtaining the value range of have been described in detail in Example 2 and will not be repeated here.

[0190] The exhaust gas treatment system provided in Example 3 of the present invention can control the temperature of the exhaust gas to a preset target temperature value T by adding an exhaust gas preheating treatment device. 1目标温度 The exhaust gas is then input into the dry defluorination device for dry defluorination treatment within the value range of , which can ultimately make the defluorination treatment of the exhaust gas in the dry defluorination device more efficient.

[0191] Example 4

[0192] This embodiment 4 provides an exhaust gas treatment system for a rotary kiln for recycling and calcining waste lithium batteries. Based on embodiment 3, the dry defluorination device control module in the dry defluorination device in the exhaust gas treatment system is optimized and improved. The optimization and improvement are the same as the optimization and improvement of the dry defluorination device control module in embodiment 1. For specific optimization and improvement, please refer to the specific content of embodiment 1 and will not be repeated here.

[0193] Example 5

[0194] This embodiment 5 provides an exhaust gas treatment system for a rotary kiln used for recycling and calcining waste lithium batteries. Based on embodiment 3, the incineration device control module of the incineration device in the exhaust gas treatment system is optimized and improved. The optimization and improvement are the same as the optimization and improvement of the incineration device control module in embodiment 1. For specific optimization and improvement, please refer to the specific content of embodiment 1 and will not be repeated here.

[0195] Example 6

[0196] This embodiment 6 provides an exhaust gas treatment system for a rotary kiln for recycling and calcining waste lithium batteries. Based on embodiment 3, the dry defluorination device control module in the dry defluorination device in the exhaust gas treatment system and the incineration device control module in the incineration device in the exhaust gas treatment system are optimized and improved. The optimization and improvement are the same as the optimization and improvement of the incineration device control module and the incineration device control module in embodiment 1. For the specific optimization and improvement, please refer to the specific content of embodiment 1 and will not be repeated here.

[0197] It should be noted that all technical features of the technical solutions in Example 1 and Example 2 can be applied to Examples 3 to 6. Those skilled in the art can select corresponding technical features from Example 1 and Example 2 and apply them to Examples 3 to 6 as needed, thereby forming a new technical solution.

[0198] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A waste gas treatment system for a rotary kiln used for recycling and calcining waste lithium batteries, the waste gas treatment system comprising a dry defluorination device, an incineration device, a denitration device, an alkali solution spraying device, and a water purification device connected in sequence, and a main control system for controlling the working states of the dry defluorination device, the incineration device, the denitration device, the alkali solution spraying device, and the water treatment device, characterized in that: The main control system includes an exhaust gas treatment system main control module, a dry defluorination device control module, an incineration device control module, a denitrification device control module, an alkali solution spraying device control module, and a water purification device control module respectively connected to the exhaust gas treatment system main control module; The incineration device control module includes: Incineration main control module; a second detection module connected to the incineration main control module, configured to detect and obtain the flow rate S2 and temperature T2 of the exhaust gas in the incineration device, and transmit the detected flow rate S2 and temperature T2 to the incineration main control module; a second valve control module connected to the incineration main control module, for controlling the on / off state of the second valve module, the second valve module being used as a switch for allowing the waste gas to be treated to enter the incineration device for treatment, and as a switch for discharging the waste gas in the incineration device; A heating power control module, connected to the incineration main control module, for controlling the heating power of the incineration device; Wherein, the heating power control module is based on the formula P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incinerator, where k is a constant, T 2初始温度 is the initial temperature of the exhaust gas entering the incineration device, T 2目标温度 The target temperature value for the incineration device to heat the exhaust gas at high temperature; The exhaust gas treatment system also includes an exhaust gas preheating treatment device, which is used to control the temperature of the exhaust gas at a preset target temperature value T 1目标温度 The target temperature value T is then input into the dry defluorination device. 1目标温度 The value range of is obtained according to the following method: Establishing a defluorination purification rate database that corresponds to the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1, and establishing a relationship PE1 [n] = f1 (T1 [n]) based on the relationship between the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1; Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature; According to the curve law of the curve diagram, the data is fitted using the polynomial fitting form to obtain the relationship PE1 [n] = K1 * T1 [n] 2 +K2*T1【n】 1 +K3, Let n 1S To achieve the target defluorination purification rate PE 1达标 The lowest temperature value, n 1L To achieve the target defluorination purification rate PE 1达标 The maximum temperature value; the value range of n is selected as [n 1S, n 1L 】, use the polynomial fitting form to fit the data and get the relationship PE1【n】=K1*T1【n】 2 +K2*T1【n】 1 + the corresponding values ​​of K1, K2, and K3 in K3, thereby finally obtaining the target temperature value T 1目标温度 The value range of .

2. The exhaust gas treatment system according to claim 1, characterized in that The target temperature value T 2目标温度 The target incineration purification rate PE to be achieved by the incineration device 2达标 The target temperature value T is obtained by the following method: 2目标温度 : Establishing an incineration purification rate database that corresponds to the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2, and establishing a relationship PE2[n]=f2(T2[n]) based on the relationship between the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2; Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature; According to the curve law of the curve diagram, the relationship PE2 [n] = f2 (T2 [n]) is fitted using the fitting form of the logarithmic function to obtain the relationship PE2 [n] = alog b T2[n]+c; Let n 2S To achieve the target incineration purification rate PE 2达标 The lowest temperature value, n 2L To achieve the target incineration purification rate PE 达标 The maximum temperature value is selected in the range of n [n 2S ,n 2L 】, the data is fitted using the logarithmic function, and the relationship PE2【n】=alog b The corresponding values ​​of a, b, and c in T2[n]+c are used to obtain the target incineration purification rate PE 2达标 and the target temperature T 2目标温度 The accurate relationship between them finally obtains the target temperature value T 2目标温度 .

3. The exhaust gas treatment system according to claim 2, characterized in that: The dry defluorination device control module includes: Dry defluorination main control module, a first detection module connected to the dry defluorination main control module, for detecting and obtaining the flow rate S1 and HF concentration Q1 of the exhaust gas in the dry defluorination device, and transmitting the detected flow rate S1 and HF concentration Q1 to the dry defluorination main control module; a first valve control module connected to the dry defluorination main control module, for controlling the on / off state of the first valve module, the first valve module being used as a switch for allowing the waste gas to be treated to enter the dry defluorination device for treatment, and as a switch for discharging the waste gas in the dry defluorination device; A defluorination medium replacement reminder module is connected to the dry defluorination main control module and is used to send a reminder signal to replace the defluorination medium; The dry defluorination main control module records the total fluoride load W according to the formula W=∑S1*Q1, wherein the parameter S1 is the flow rate of the exhaust gas in the dry defluorination device, and the parameter Q1 is the HF concentration of the exhaust gas in the dry defluorination device; when the dry defluorination main control module determines that the total fluoride load W is greater than or equal to the preset value A, the dry defluorination main control module outputs a corresponding control signal to control the defluorination medium replacement reminder module to issue the reminder signal.

4. The exhaust gas treatment system according to claim 3, characterized in that: The denitrification device control module includes: Denitrification main control module; a third detection module, connected to the denitration main control module, for detecting and obtaining one or more parameters of the exhaust gas in the denitration device, including temperature, flow, pressure or NOx concentration, and transmitting the detected parameters to the denitration main control module; a third valve control module connected to the denitration main control module, for controlling the on / off state of the third valve module, the third valve module being used as a switch for allowing the waste gas to be treated to enter the denitration device for treatment, and as a switch for discharging the waste gas in the denitration device; The alkali solution spraying device control module includes: Alkali solution spraying main control module; a fourth detection module, connected to the alkali solution spray main control module, for detecting and obtaining one or more parameters of the exhaust gas in the alkali solution spray device, including temperature, flow rate, air pressure or acid gas concentration, and transmitting the detected parameters to the alkali solution spray main control module; a fourth valve control module connected to the alkali solution spray main control module, for controlling the on / off state of the fourth valve module, the fourth valve module being used as a switch for allowing the waste gas to be treated to enter the alkali solution spray device for treatment, and as a switch for discharging the waste gas or liquid in the alkali solution spray device; The water purification device control module includes: Water purification processing main control module; a fifth detection module, connected to the water purification treatment main control module, for detecting and obtaining one or more parameters of the temperature, flow rate, TDS or solid impurities of the liquid in the water purification treatment device, and transmitting the detected parameters to the water purification treatment main control module; The fifth valve control module is connected to the water purification treatment main control module and is used to control the switching state of the fifth valve module. The fifth valve module is used as a switch for the wastewater to be treated to enter the water purification treatment device for treatment, and is used as a switch for discharging the liquid in the water purification treatment device.

5. A method for treating waste gas from a rotary kiln used for recycling and calcining waste lithium batteries, applied to a waste gas treatment system comprising a dry defluorination device, an incineration device, a denitrification device, an alkali solution spraying device, and a water purification device connected in sequence, the waste gas treatment method comprising: Step S10, dry defluorination: the waste gas to be treated is input into a dry defluorination device for dry defluorination treatment to remove fluoride in the waste gas; Step S20, incineration: the waste gas after the dry defluorination step is fed into the incineration device for incineration treatment to decompose and oxidize harmful organic matter and volatile organic compounds in the waste gas at high temperature; Step S30, denitration: the waste gas treated in the incineration step is input into the denitration device for denitration treatment to remove nitrogen oxides in the waste gas; Step S40, alkali solution spraying: The waste gas treated in the denitrification step is input into the alkali solution spraying device for alkali solution spraying treatment to neutralize the acidic gas in the waste gas, prevent the acidic substances from polluting the environment, and ensure that the waste gas treated by the alkali solution spraying meets the emission standards before being discharged; Step S50, water purification: purifying the wastewater generated by the alkali solution spraying treatment to ensure that the purified wastewater meets the discharge standards before being discharged; The step S10 further includes: Control the exhaust gas temperature at the preset target temperature value T 1目标温度 The target temperature value T is then input into the dry defluorination device. 1目标温度 The value range of is obtained according to the following method: Establishing a defluorination purification rate database that corresponds to the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1, and establishing a relationship PE1 [n] = f1 (T1 [n]) based on the relationship between the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1; Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature; According to the curve law of the curve diagram, the data is fitted using the polynomial fitting form to obtain the relationship PE1 [n] = K1 * T1 [n] 2 +K2*T1【n】 1 +K3, Let n 1S To achieve the target defluorination purification rate PE 1达标 The lowest temperature value, n 1L To achieve the target defluorination purification rate PE 1达标 The maximum temperature value; the value range of n is selected as [n 1S, n 1L 】, use the polynomial fitting form to fit the data and get the relationship PE1【n】=K1*T1【n】 2 +K2*T1【n】 1 + the corresponding values ​​of K1, K2, and K3 in K3, thereby finally obtaining the target temperature value T 1目标温度 The value range of .

6. The waste gas treatment method according to claim 5, characterized in that: The step S10 further includes: The temperature of the exhaust gas input into the dry defluorination device is detected. When it is detected that the temperature of the exhaust gas input into the dry defluorination device is not within the preset target temperature value T 1目标温度 When the temperature is within the range of the target temperature, the corresponding reminder signal is output so that the staff can control the waste gas to be treated within the preset target temperature value T in time. 1目标温度 The value is then input into the dry defluorination device for treatment within the range of .

7. The waste gas treatment method according to claim 6, characterized in that: The step S10 further includes: In step S10, during the dry defluorination treatment of the exhaust gas, when the dry defluorination device detects that the total fluoride load W is greater than or equal to the preset value A, the dry defluorination device sends a reminder signal for replacing the defluorination medium to remind the staff to replace the defluorination medium in time; The dry defluorination device records the total fluoride load W according to the formula W=∑S1*Q1, wherein the parameter S1 is the flow rate of the exhaust gas in the dry defluorination device, and the parameter Q1 is the HF concentration of the exhaust gas in the dry defluorination device.

8. The waste gas treatment method according to claim 5, 6 or 7, characterized in that: In step S20, during the incineration process of the waste gas, the heating power control module of the incineration device controls the heating power of the incineration device according to the formula P 加热 =k*S2*(T 2初始温度 -T 2目标温度 ) to control the heating power of the incinerator, where k is a constant, T 2初始温度 is the initial temperature of the exhaust gas entering the incineration device, T 2目标温度 The target temperature value for the incineration device to heat the exhaust gas at high temperature.

9. The waste gas treatment method according to claim 8, characterized in that: The target temperature value T 2目标温度 The target incineration purification rate PE to be achieved by the incineration device 2达标 The target temperature value T is obtained by the following method: 2目标温度 : Establishing an incineration purification rate database that corresponds to the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2, and establishing a relationship PE2[n]=f2(T2[n]) based on the relationship between the incineration purification rate PE2 of the incineration device and the exhaust gas temperature T2; Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature; According to the curve law of the curve diagram, the relationship PE2 [n] = f2 (T2 [n]) is fitted using the fitting form of the logarithmic function to obtain the relationship PE2 [n] = alog b T2[n]+c; Let n 2S To achieve the target incineration purification rate PE 2达标 The lowest temperature value, n 2L To achieve the target incineration purification rate PE 达标 The maximum temperature value is selected in the range of n as [n 2S, n 2L 】, the data is fitted using the logarithmic function, and the relationship PE2【n】=alog b The corresponding values ​​of a, b, and c in T2[n]+c are used to finally obtain the target temperature value T 2目标温度 .

10. A waste gas treatment system for a rotary kiln used for recycling and calcining waste lithium batteries, the waste gas treatment system comprising a dry defluorination device, an incineration device, a denitration device, an alkali solution spraying device, and a water purification device connected in sequence, and a main control system for controlling the working states of the dry defluorination device, the incineration device, the denitration device, the alkali solution spraying device, and the water treatment device, characterized in that: The exhaust gas treatment system also includes an exhaust gas preheating treatment device, which is used to control the temperature of the exhaust gas at a preset target temperature value T 1目标温度 The target temperature value T is then input into the dry defluorination device. 1目标温度 The value range of is obtained according to the following method: Establishing a defluorination purification rate database that corresponds to the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1, and establishing a relationship PE1 [n] = f1 (T1 [n]) based on the relationship between the defluorination purification rate PE1 of the dry defluorination device and the exhaust gas temperature T1; Sampling the exhaust gas temperature values ​​and their corresponding exhaust gas purification rate values ​​in the exhaust gas purification rate database, and sorting the exhaust gas temperature values ​​from small to large to draw a curve diagram showing the relationship between the exhaust gas purification rate and the exhaust gas temperature; According to the curve law of the curve diagram, the data is fitted using the polynomial fitting form to obtain the relationship PE1 [n] = K1 * T1 [n] 2 +K2*T1【n】 1 +K3, Let n 1S To achieve the target defluorination purification rate PE 1达标 The lowest temperature value, n 1L To achieve the target defluorination purification rate PE 1达标 The maximum temperature value; the value range of n is selected as [n 1S, n 1L 】, use the polynomial fitting form to fit the data and get the relationship PE1【n】=K1*T1【n】 2 +K2*T1【n】 1 + the corresponding values ​​of K1, K2, and K3 in K3, thereby finally obtaining the target temperature value T 1目标温度 The value range of .

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