Tobacco sheet stem liquid wastewater thermal pretreatment device and method

Abstract

The invention discloses a thermal pretreatment device and method for tobacco sheet stem liquid wastewater, and the method comprises the steps: carrying out the thermal pretreatment of the stem liquid wastewater, collecting the spectral information of the stem liquid wastewater in the process in real time through a spectroscopy sensor, and carrying out the treatment of the collected spectral information, the concentrations of total organic matters, suspended particulate matters, proteins and humic acid in the stem liquid wastewater in the thermal pretreatment process are obtained, whether thermal pretreatment is completed or not is judged according to the concentration information of each substance, and then the thermal pretreatment time is controlled according to the judgment result. The wastewater treatment efficiency of a subsequent biological treatment unit can be effectively improved through thermal pretreatment, a monitoring index system is constructed by combining multiple spectroscopy sensors, the change of key substances and the progress of the treatment process in the thermal pretreatment process are quantified, the treatment flow is controlled accordingly, and the controllability and efficiency of thermal pretreatment are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of tobacco sheet production, and in particular relates to a device and method for thermal pretreatment of tobacco sheet stem liquid wastewater. Background Art

[0002] Stem liquid wastewater is the wastewater produced during the tobacco flake production process, where stem and leaf extracts are purified through sedimentation before concentration. Because it contains chromophores such as unsaturated conjugated double bonds, its structure is stable and complex, giving the water a black color. Due to the lack of appropriate pretreatment technology, most tobacco flake production companies treat stem liquid wastewater along with other production wastewaters by sending it into the sewage treatment system for biochemical and physicochemical treatment. However, stem liquid discharge is large, has high chroma, high chemical oxygen demand, and contains a high amount of suspended fiber matter, which can easily impact subsequent biochemical treatment units. Therefore, efficient pretreatment of stem liquid wastewater is key to ensuring the stable operation of the flake wastewater treatment system. Summary of the Invention

[0003] In order to solve the problem that tobacco sheet stem liquid wastewater is prone to impact or inhibit the subsequent biological wastewater treatment system, the present invention provides a tobacco sheet stem liquid wastewater thermal pretreatment device and method, aiming to improve the biodegradability of the main components in the stem liquid wastewater through a thermal pretreatment method, and to use a spectroscopic method to quickly detect key substances that affect the thermal pretreatment effect online, so as to improve the controllability and efficiency of the thermal pretreatment.

[0004] The present invention has found that heating stem fluid wastewater can increase the solubility of particulate matter in the wastewater and promote the hydrolysis, denaturation, and chemical bond cleavage of high-molecular compounds, thereby improving the biodegradability of stem fluid. Currently, there are no reports on thermal pretreatment of stem fluid.

[0005] The present invention also found that the main factors affecting the effect of heat treatment of stem liquid are temperature and heating time, and the aforementioned representative substances and their reaction processes can be quickly estimated through absorption spectroscopy and fluorescence spectroscopy, thereby guiding the operation of the thermal pretreatment process, especially the control of treatment time. By acquiring and quantitatively calculating spectral information, process information of thermal pretreatment can be obtained, such as the conversion amount of macromolecular substances or the increase in solubility of particulate matter, thereby guiding the regulation of thermal pretreatment temperature and time. The use of spectral detection methods for wastewater component analysis has been maturely applied, but there has been no report on the process control and parameter optimization of stem liquid pretreatment by correlating several spectral methods and directly integrating them for application.

[0006] To achieve the purpose, the present invention adopts the following technical solutions:

[0007] The present invention first provides a tobacco sheet stem liquid wastewater thermal pretreatment device, including a stem liquid storage container, a wastewater transport pump, a thermal pretreatment container, a heating system, a spectroscopic sensor and a control system; the stem liquid storage container and the thermal pretreatment container have a cavity inside, and both are connected to the inlet and outlet of the wastewater transport pump respectively; the heating system acts in the thermal pretreatment container, the spectroscopic sensor collects spectral information in the thermal pretreatment container, and the heating system and the spectroscopic sensor are both data-connected to the control system.

[0008] The stem liquid storage container and the heat pretreatment container are preferably stainless steel containers, concrete containers, or containers formed into fiberglass modular shapes.

[0009] Furthermore, the heating system includes a steam pump, a steam pipe and a pipe valve; the steam pipe is located in the thermal pretreatment container, and both ends extend outside the thermal pretreatment container; the inlet end of the steam pipe is connected in sequence from the inlet to the outlet direction with the steam pump for gas supply and the pipe valve for controlling the on-off of the steam pipe.

[0010] Furthermore, the middle section of the steam pipe is a serpentine tubular structure and is evenly distributed in the pretreatment container.

[0011] Furthermore, the spectral sensor includes a transmission spectrum sensor, a scattering spectrum sensor, and a fluorescence spectrum sensor. The transmission spectrum sensor can be selected at wavelengths of 254 and 564 nm. By processing the information collected by the transmission spectrum, the changes in the total amount of dissolved organic matter during the thermal pretreatment process can be obtained. The scattering spectrum sensor can be selected at a wavelength of 860 nm. By processing the information collected by the scattering spectrum, the changes in suspended particulate matter during the thermal pretreatment process can be obtained. The fluorescence spectrum sensor can be selected at an excitation wavelength of 280 nm. By processing the information collected by the fluorescence spectrum, the changes in protein and humic acid substances during the thermal pretreatment process can be obtained.

[0012] Furthermore, the control system is used to process the spectral information collected by the spectral sensor, determine whether the thermal pretreatment has been completed, and then control the heating time of the heating system according to the determination result.

[0013] The present invention further provides a method for thermal pretreatment of tobacco sheet stem liquid wastewater, which utilizes the above-mentioned thermal pretreatment device, firstly transports the stem liquid wastewater stored in the stem liquid storage container to the thermal pretreatment container through a wastewater transport pump, turns on the heating system, and starts heat preservation after reaching the set temperature, and thermally pretreats the stem liquid wastewater, and collects the spectral information of the stem liquid wastewater in real time during the thermal pretreatment process through a spectroscopic sensor, processes the spectral information collected by the spectroscopic sensor through a control system, obtains the concentrations of total organic matter, suspended particulate matter, protein and humic acid in the stem liquid wastewater during the thermal pretreatment process, and judges whether the thermal pretreatment has been completed based on the concentration information of each substance, and then controls the time of the thermal pretreatment based on the judgment result.

[0014] Furthermore, waste heat from the tobacco sheet manufacturing process can be used as a steam source, which is pumped into a steam pipe through a steam pump to heat the stem liquid.

[0015] Furthermore, the spectral information includes transmission spectrum information, scattering spectrum information and fluorescence spectrum information:

[0016] 1. Calculate the total organic matter concentration in the stem liquid wastewater using the absorbance value of the stem liquid wastewater in the transmission spectrum information.

[0017] Preferably, the dual wavelength method is used to detect the absorbance of the stem liquid wastewater by a transmission spectrum sensor with a wavelength of 254 nm, and the transmission spectrum sensor with a wavelength of 546 nm is used as a reference to calibrate the results. According to formula C COD =K1*A λ254 -K2*A λ564 , calculate the COD concentration in the stem wastewater, where C COD is the concentration of total organic matter COD in the stem liquid wastewater, K1 and K2 are the proportional coefficients at 254nm wavelength and 546nm wavelength respectively, A λ254 With A λ564 These are the absorbance values ​​of stem liquid wastewater at wavelengths of 254nm and 564nm respectively.

[0018] 2. Calculate the concentration of suspended particulate matter in the stem liquid wastewater using the scattered signal in the scattered spectrum information:

[0019] Preferably, the concentration of suspended particulate matter in the stem liquid wastewater is determined by scattering spectroscopy based on an 860 nm wavelength. The scattering signal generated by irradiating the stem liquid wastewater with an 860 nm wavelength light source is calculated according to the Rayleigh scattering theory formula I. S =K3*N*I0 / λ^4, calculate the concentration of suspended particles N in the stem wastewater, where I S is the scattered light intensity, I0 is the incident light intensity, λ is the incident light wavelength, N is the suspended particle concentration (i.e. the number of particles per unit volume of water), and K3 is the proportional coefficient.

[0020] 3. Calculate the protein concentration and humic acid concentration in the stem liquid wastewater using the intensity of the fluorescent emission light in the fluorescence spectrum information:

[0021] The concentrations of protein and humic acid in wastewater were estimated using fluorescence excited at a wavelength of 280 nm.

[0022] The concentration of protein is quantified by collecting the light signal intensity at an emission wavelength of 350 nm, and the formula is C Pr =K4*F Em350 +C1, where C Pr is the protein concentration, K4 is the proportionality coefficient, F Em350 is the intensity of the fluorescent emission light at 350 nm, and C1 is a constant.

[0023] The concentration of humic acid is quantified by collecting the light signal intensity at emission wavelengths of 420, 450, and 480 nm, and the formula is C HA =K5*F Em420 +K6*F Em450 +K7*F Em480 +C2, where C HA is the humic acid concentration, K5, K6 and K7 correspond to the proportional coefficients of fluorescence intensity at different wavelengths, F Em420 、F Em450 、F Em480 are the intensities of the fluorescent emission light at 420, 450 and 480 nm respectively, and C2 is a constant.

[0024] Furthermore, the method for judging whether the thermal pretreatment is completed according to the concentrations of total organic matter, suspended particulate matter, protein and humic acid in the stem liquid wastewater during the thermal pretreatment process is as follows:

[0025] a. According to the set temperature and time conditions of thermal pretreatment, the thermal pretreatment data of the stem liquid wastewater to be treated is monitored for one month, and the average initial concentrations of COD, suspended particulate matter, protein and humic acid in the stem liquid wastewater before thermal pretreatment are obtained, which are recorded as C 1 0.C 2 0.C 3 0.C 4 0, and obtain the average concentration after heat pretreatment, respectively recorded as C 1 T 、C 2 T 、C 3 T 、C 4 T .

[0026] b. During the actual thermal pretreatment operation, the initial concentrations of COD, suspended particulate matter, protein and humic acid in the stem wastewater are recorded as c1 0, c 2 0, c 3 0, c 4 0, and the real-time values ​​at time t are recorded as c 1 t 、c 2 t 、c 3 t 、c 4 t The progress of the thermal pretreatment effect is quantitatively estimated at time t using the following formula:

[0027]

[0028] When η t When ≥80%, it can be judged that the thermal pretreatment is complete, heating is stopped and water is discharged; if η t <80%, continue heating.

[0029] Occasionally, there is a problem that this value cannot be reached. From a practical point of view, if this value is always lower than 80% and the total heat pretreatment time exceeds 1.0h, heating is stopped and water is discharged.

[0030] Furthermore, the temperature is set to 70-90°C. After heating to the set temperature, spectrum data collection is started until the "η" calculated based on the spectrum data is t "When the heat pretreatment rate is ≥80%, the heat pretreatment process ends. Multiple tests in the early stages of the present invention have shown that the heat pretreatment can achieve the best effect within 0.5-1.0 hours. If the time is shortened, the effect is poor, and if it is extended further, the effect is difficult to further improve.

[0031] The beneficial effects of the present invention are:

[0032] This invention proposes a novel method for improving the efficiency of stem slurry treatment. Through thermal pretreatment, it can effectively improve the wastewater treatment efficiency of subsequent biological treatment units, such as increasing methane yield in anaerobic systems. During the thermal pretreatment process, the invention combines multiple spectroscopic sensors to construct a monitoring indicator system. Combined with the construction of corresponding algorithms, this system quantifies the changes in key substances and the progress of the treatment process during the thermal pretreatment process. This information is then used to control the treatment process, significantly improving the controllability and efficiency of the thermal pretreatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a system architecture diagram of the thermal pretreatment device provided by the present invention, with the following numbers in the figure: 1. stem liquid storage container; 2. wastewater transport pump; 3. steam pump; 4. thermal pretreatment container; 5. heating system; 6. spectroscopy sensor; 7. control system.

[0034] Figure 2is the change of the process value η during the thermal pretreatment process and the contribution rate of each component to it;

[0035] Figure 3 To control the signal acquisition and process identification process of the control system;

[0036] Figure 4 It is through the thermal pretreatment that the anaerobic unit produces methane to improve the overall effect; DETAILED DESCRIPTION

[0037] The following is a detailed description of the specific embodiments of the present invention with reference to the accompanying drawings and examples. The following is merely an example and illustration of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described, or replace them with similar methods. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0038] like Figure 1 As shown, this embodiment provides a tobacco sheet stem liquid wastewater thermal pretreatment device, including a stem liquid storage container 1, a wastewater transport pump 2, a thermal pretreatment container 4, a heating system 5, a spectroscopic sensor 6 and a control system 7.

[0039] The stem liquid storage container 1 and the thermal pretreatment container 4 have internal cavities, both of which are connected to the inlet and outlet of the wastewater transport pump 2, respectively. A heating system 5 acts on the thermal pretreatment container 4, and a spectroscopic sensor 6 collects spectral information within the thermal pretreatment container 4. The heating system 5 and the spectroscopic sensor 6 are both in data communication with a control system 7. The heating system 5 includes a steam pump 3, a steam pipe, and a pipe valve.

[0040] The steam pipe is located in the heat pretreatment container 4, with both ends extending outside the heat pretreatment container 4; the inlet end of the steam pipe is connected in sequence from the inlet to the outlet with a steam pump 3 for gas supply and the pipe valve for controlling the on-off of the steam pipe; the middle section of the steam pipe is a serpentine tubular structure and is evenly distributed in the pretreatment container 4.

[0041] The spectroscopy sensor 6 includes a transmission spectrum sensor, a scattering spectrum sensor, and a fluorescence spectrum sensor.

[0042] The present invention further provides a method for thermal pretreatment of tobacco sheet stem liquid wastewater, specifically: first, the stem liquid wastewater stored in the stem liquid storage container 1 is transported to the thermal pretreatment container 4 through the wastewater transport pump 2, the heating system 5 is turned on, and after reaching the set temperature, insulation is started to perform thermal pretreatment on the stem liquid wastewater, and the spectral information of the stem liquid wastewater during the thermal pretreatment process is collected in real time by the spectroscopic sensor 6, the spectral information collected by the spectroscopic sensor is processed by the control system 7 to obtain the concentrations of total organic matter, suspended particulate matter, protein and humic acid in the stem liquid wastewater during the thermal pretreatment process, and whether the thermal pretreatment has been completed is judged based on the concentration information of each substance, and then the heating time of the heating system is controlled based on the judgment result.

[0043] Spectral information includes transmission spectrum information, scattering spectrum information and fluorescence spectrum information;

[0044] 1. Calculate the total organic matter COD concentration in the stem liquid wastewater using the absorbance value of the stem liquid wastewater in the transmission spectrum information:

[0045] Preferably, the dual wavelength method is used to detect the absorbance of the stem liquid wastewater by a transmission spectrum sensor with a wavelength of 254 nm, and the transmission spectrum sensor with a wavelength of 546 nm is used as a reference to calibrate the results. According to formula C COD =K1*A λ254 -K2*A λ564 , calculate the COD concentration in the stem wastewater, where C COD is the concentration of total organic matter COD in the stem liquid wastewater, K1 and K2 are the proportional coefficients at 254nm wavelength and 546nm wavelength respectively, A λ254 With A λ564 The absorbance values ​​of stem liquid wastewater at wavelengths of 254nm and 564nm are respectively. By collecting actual stem liquid wastewater, the actual COD concentration is calibrated using the potassium dichromate method, and the A λ254 With A λ564 , obtain a series of concentration and absorbance values, as shown in Table 1.

[0046] Table 1

[0047] <![CDATA[A λ254 (L / (g·cm))]]> 8.312 7.921 7.214 6.552 5.834 4.325 3.412 2.121 <![CDATA[A λ564 (L / (g·cm))]]> 10.101 9.013 7.121 6.521 5.693 5.091 4.821 3.977 COD (mg / L) 45000 41000 32000 28000 23000 16000 12000 8000

[0048] Then, the least squares method is used to perform binary linear regression fitting to obtain K1 and K2, and the quantitative formula is obtained:

[0049] C COD =2717.7*A λ254 +3563.6*A λ564 -13210.5

[0050] This relationship can be used for quantitative analysis of the subsequent thermal pretreatment process.

[0051] 2. Use the scattered signal in the scattered spectrum information to calculate the concentration of suspended particulate matter in the stem liquid wastewater.

[0052] Preferably, the concentration of suspended particulate matter in the stem liquid wastewater is determined by scattering spectroscopy based on an 860 nm wavelength. The scattering signal generated by irradiating the stem liquid wastewater with an 860 nm wavelength light source is calculated according to the Rayleigh scattering theory formula I. S =K3*N*I0 / λ^4, calculate the concentration of suspended particles N in the stem wastewater, where I S is the scattered light intensity, I0 is the incident light intensity, λ is the incident light wavelength, N is the suspended particle concentration (i.e. the number of particles per unit volume of water), K3 is the proportional coefficient, and the formula is used to convert N = λ^4*I S / (K3*I0). Actual stem cell wastewater was collected and the scattered light intensity was measured using a scattered light intensity sensor. The actual particulate matter concentration was filtered using a 0.22 μm pore size filter membrane, and then dried and weighed to obtain the accurate particulate matter content value, as shown in Table 2.

[0053] Table 2

[0054]

[0055]

[0056] Then, the least squares method is used to perform binary linear regression fitting to obtain K3 and the quantitative formula:

[0057] I S =7.41*10^7*N*I0 / λ^4

[0058] This relationship can be used for quantitative analysis of the subsequent thermal pretreatment process.

[0059] 3. Use the intensity of the fluorescent emission light in the fluorescence spectrum information to calculate the protein concentration and humic acid concentration in the stem liquid wastewater.

[0060] The concentrations of protein and humic acid in wastewater were estimated using fluorescence excited at a wavelength of 280 nm.

[0061] The concentration of protein is quantified by collecting the light signal intensity at an emission wavelength of 350 nm, and the formula is C Pr =K4*F Em350 +C1, where C Pr is the protein concentration, K4 is the proportionality coefficient, F Em350 is the intensity of the fluorescence emission light at 350nm, C1 is a constant; the humic acid concentration is quantified by collecting the light signal intensity at emission wavelengths of 420, 450 and 480nm, and the formula is C HA =K5*F Em420+K6*F Em450 +K7*F Em480 +C2, where C HA is the humic acid concentration, K5, K6 and K7 correspond to the proportional coefficients of fluorescence intensity at different wavelengths, F Em420 、F Em450 、F Em480 The fluorescence emission intensity at 420, 450, and 480 nm is respectively, and C2 is a constant. Actual stem wastewater was collected and the fluorescence peak intensity at the corresponding wavelength was measured using a fluorescence intensity sensor. The actual protein concentration and humic acid concentration were quantified using the modified Lowery method, as shown in Table 3.

[0062] Table 3

[0063] <![CDATA[F Em350 ]]> 6308 4893 3219 2010 1201 Protein concentration (mg / L) 302.8 245.1 187.5 119.7 55.2 <![CDATA[F Em420 ]]> 2543 1896 1452 1207 698 <![CDATA[F Em450 ]]> 7065 5552 3101 2545 1254 <![CDATA[F Em480 ]]> 4454 4201 3501 2650 2065 Humic acid concentration (mg / L) 601.4 550.2 355.8 278.9 150.9

[0064] Then, the least squares method was used to perform binary linear regression fitting to obtain K4 and C1, and the quantitative formula of protein was obtained:

[0065] C Pr =0.0465*F Em350 +17.99

[0066] Similarly, the least squares method was used to perform binary linear regression fitting to obtain K4, K5, K6, K7 and C1, and the quantitative formula of humic acid was obtained:

[0067] C HA =0.102*F Em420 +0.060*F Em450- 0.081*F Em480 -66.17

[0068] This relationship can be used for quantitative analysis of the subsequent thermal pretreatment process.

[0069] The steps to determine whether the thermal pretreatment is completed according to the concentration of total organic matter, suspended particulate matter, protein and humic acid in the stem liquid wastewater during the thermal pretreatment process are as follows:

[0070] a. According to the set heat pretreatment temperature (90°C) and time conditions (90 minutes, to ensure the complete reaction, the time here is longer than the actual treatment time of 45 minutes later), the heat pretreatment data of the stem liquid wastewater to be treated was monitored for one month (tested once every two days, a total of 15 batches), and the average initial concentrations of COD, suspended particulate matter, protein and humic acid in the stem liquid wastewater before heat pretreatment were obtained, which were recorded as C 1 0.C 2 0.C 3 0.C 4 0, and obtain the average concentration after heat pretreatment, respectively recorded as C1 T 、C 2 T 、C 3 T 、C 4 T The data are shown in Table 4.

[0071] Table 4

[0072]

[0073] From the above table we can calculate:

[0074] C 1 0=40006.2;C 2 0=5002.7;C 3 0=183.9;C 4 0=390.6;

[0075] C 1 T =43225.1;C 2 T =3845.7; C 3 T =122.1; C 4 T =333.7;

[0076] b. During the actual thermal pretreatment operation, the initial concentrations of COD, suspended particulate matter, protein and humic acid in the stem liquid wastewater are recorded as c 1 0, c 2 0, c 3 0, c 4 0, and the real-time values ​​at time t are recorded as c 1 t 、c 2 t 、c 3 t 、c 4 t The progress of the thermal pretreatment effect is quantitatively estimated at time t using the following formula:

[0077]

[0078] Specifically, taking a batch of thermal pretreatment detection and calculation process data as an example, the corresponding data is shown in Table 5:

[0079] Table 5

[0080] Thermal pretreatment time (min) 0 15 30 45 <![CDATA[A λ254 (L / (g·cm))]]> 8.512 8.742 9.089 9.208 <![CDATA[A λ564 (L / (g·cm))]]> 8.271 8.513 8.612 8.621 COD concentration (mg / L) 39397.1 40884.6 42180.4 42535.9 <![CDATA[Is(W / m 2 )]]> 181 165 149 117 Suspended particulate matter concentration (mg / L) 5239.8 4776.6 4313.4 3387 <![CDATA[F Em350 ]]> 6252 6123 5609 5169 Protein concentration (mg / L) 308.7 302.7 278.8 258.3 <![CDATA[F Em420 ]]> 2354 2010 1997 1806 <![CDATA[F Em450 ]]> 6567 6007 5551 4891 <![CDATA[F Em480 ]]> 4201 3808 3605 3428 Humic acid concentration (mg / L) 227.7 190.8 178.6 133.8 <![CDATA[η COD (%)]]> 0 11.2 21.6 24.5 <![CDATA[η SS (%)]]> 0 8.5 15.4 24.1 <![CDATA[η Pr (%)]]> 0 2.2 10.2 15.9 <![CDATA[η HA (%)]]> 0 12.6 15.8 22.6 <![CDATA[η t (%)]]> 0 34.5 62.9 87.1

[0081] in:

[0082] The COD concentration value is calculated according to the following formula: COD =2717.7*A λ254 +3563.6*A λ564 -13210.5

[0083] The suspended particulate matter concentration is calculated as follows: S =7.41*10^7*N*I0 / λ^4

[0084] The protein concentration was calculated as follows: C Pr =0.0465*F Em350 +17.99

[0085] The humic acid concentration is calculated as follows: HA =0.102*F Em420 +0.060*F Em450- 0.081*F Em480 -66.17

[0086] The initial concentration values ​​of COD, suspended particulate matter, protein and humic acid in the stem wastewater (i.e., the values ​​at 0 min of heat pretreatment) can be obtained through the above calculations, which are respectively denoted as c 1 0, c 2 0, c 3 0, c 4 0; and the real-time value at time t, respectively denoted as c 1 t 、c 2 t 、c 3 t 、c 4 t ;

[0087] The overall progress of thermal pretreatment is calculated by the formula:

[0088] Where C 1 0=40006.2;C 2 0=5002.7;C 3 0=183.9;C 4 0=390.6;C 1 T =43225.1;C 2 T =3845.7; C 3 T =122.1; C 4 T =333.7.

[0089] The treated wastewater with different heat pretreatment times was pumped into a normally operating UASB reactor. The methane production efficiency of the UASB system was then tested, measured in terms of volumetric efficiency (i.e., the volume of methane produced per liter of reactor volume). The comparison showed the effect of heat pretreatment on the biodegradability of the wastewater. Figure 4 As shown, thermal pretreatment of wastewater can improve the efficiency of anaerobic treatment units.

[0090] The above data demonstrate that the present invention, through thermal pretreatment of stem slurry, can effectively improve the wastewater treatment efficiency of subsequent biological treatment units. During the thermal pretreatment process, the present invention utilizes a combination of multiple spectroscopic sensors to construct a monitoring indicator system. Combined with the construction of corresponding algorithms, this system quantifies the changes in key substances and the progress of the treatment process during the thermal pretreatment process. This information is then used to control the treatment process, significantly improving the controllability and efficiency of the thermal pretreatment.

Claims

1. A device for thermal pretreatment of tobacco sheet stem liquid wastewater, characterized by: It includes a stem liquid storage container (1), a wastewater transport pump (2), a heat pretreatment container (4), a heating system (5), a spectroscopy sensor (6) and a control system (7); The stem liquid storage container (1) and the heat pretreatment container (4) have cavities therein, and are respectively connected to the inlet and outlet of the wastewater transport pump (2); The heating system (5) acts on the thermal pretreatment container (4), the spectral sensor (6) collects spectral information in the thermal pretreatment container (4), and the heating system (5) and the spectral sensor (6) are both in data communication with the control system (7).

2. The device for thermal pretreatment of tobacco sheet stem liquid wastewater according to claim 1, characterized in that: The heating system (5) includes a steam pump (3), a steam pipe and a pipe valve; The steam pipe is located in the heat pretreatment container (4), with both ends extending outside the heat pretreatment container (4); the steam pump (3) for gas supply and the pipe valve for controlling the on / off of the steam pipe are sequentially connected at the inlet end of the steam pipe from the inlet to the outlet; the middle section of the steam pipe is in a serpentine tubular structure and is evenly distributed in the pretreatment container (4).

3. The device for thermal pretreatment of tobacco sheet stem liquid wastewater according to claim 1, characterized in that: The spectral sensor (6) comprises a transmission spectrum sensor, a scattering spectrum sensor and a fluorescence spectrum sensor.

4. The device for thermal pretreatment of tobacco sheet stem liquid wastewater according to claim 1, characterized in that: The control system is used to process the spectral information collected by the spectral sensor, determine whether the thermal pretreatment has been completed, and then control the heating time of the heating system according to the determination result.

5. A method for thermal pretreatment of tobacco sheet stem liquid wastewater, characterized in that: By using the device described in any one of claims 1 to 4, the stem liquid wastewater stored in the stem liquid storage container (1) is first transported to the thermal pretreatment container (4) through the wastewater transport pump (2), the heating system (5) is turned on, and after reaching the set temperature, insulation is started to perform thermal pretreatment on the stem liquid wastewater, and the spectral information of the stem liquid wastewater during the thermal pretreatment process is collected in real time by the spectroscopic sensor (6), the spectral information collected by the spectroscopic sensor is processed by the control system (7), and the concentrations of total organic matter, suspended particulate matter, protein and humic acid in the stem liquid wastewater during the thermal pretreatment process are obtained, and whether the thermal pretreatment has been completed is judged based on the concentration information of each substance, and then the time of the thermal pretreatment is controlled based on the judgment result.

6. The method for thermal pretreatment of tobacco sheet stem liquid wastewater according to claim 5, characterized in that: Waste heat from the tobacco sheet manufacturing process is used as a steam source to heat the stem liquid.

7. The method for thermal pretreatment of tobacco sheet stem liquid wastewater according to claim 5, characterized in that: The set temperature for thermal pretreatment is 70-90°C.

8. The method for thermal pretreatment of tobacco sheet stem liquid wastewater according to claim 5, characterized in that: The spectral information includes transmission spectrum information, scattering spectrum information and fluorescence spectrum information; The COD concentration of total organic matter in the stem liquid wastewater is calculated using the absorbance value of the stem liquid wastewater in the transmission spectrum information; The concentration of suspended particles in stem liquid wastewater is calculated using the scattered signals in the scattered spectrum information. The protein concentration and humic acid concentration in the stem liquid wastewater were calculated using the intensity of the fluorescent emission light in the fluorescence spectrum information.

9. The method for thermal pretreatment of tobacco sheet stem liquid wastewater according to claim 5, characterized in that: The method for judging whether the thermal pretreatment is completed is based on the concentration of total organic matter, suspended particulate matter, protein and humic acid in the stem liquid wastewater during the thermal pretreatment process: a. According to the set temperature and time conditions of thermal pretreatment, the thermal pretreatment data of the stem liquid wastewater to be treated is monitored for one month, and the average initial concentrations of COD, suspended particulate matter, protein and humic acid in the stem liquid wastewater before thermal pretreatment are obtained, which are recorded as C 1 0. C 2 0.C 3 0.C 4 0, and obtain the average concentration after heat pretreatment, respectively recorded as C 1 T 、C 2 T 、C 3 T 、C 4 T ; b. During the actual thermal pretreatment operation, the initial concentrations of COD, suspended particulate matter, protein and humic acid in the stem wastewater are recorded as c 1 0, c 2 0, c 3 0, c 4 0, and the real-time values ​​at time t are recorded as c 1 t 、c 2 t 、c 3 t 、c 4 t The progress of the thermal pretreatment effect is quantitatively estimated at time t using the following formula: When η t When ≥80%, it is judged that the thermal pretreatment is complete, heating is stopped and water is discharged; if η t <80%, continue heating.

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