Method for accounting carbon emission and carbon fixation in co-production of gas and charcoal from flue-cured tobacco stalks

Abstract

The present application belongs to the technical field of biomass resource utilization, and particularly relates to a flue-cured tobacco stalk gas-char cogeneration method for simultaneous carbon sequestration and carbon emission accounting. Through flue-cured tobacco stalk collection, storage, transportation, pretreatment, pyrolysis gasification, product separation and high-value utilization, the pyrolysis temperature is controlled at 600, the heating rate and the oxygen volume fraction are controlled, and the combustible gas power generation and heating and the modified biochar field carbon sequestration are simultaneously realized to construct a carbon emission accounting model. Based on the measured data of each link, the genetic algorithm is improved to optimize the carbon sequestration contribution coefficient, and the process parameter correction mechanism is combined to accurately quantify the system net emission reduction. The present application can solve the problems of poor scene adaptability of the flue-cured tobacco stalk gas-char cogeneration technology and the lack of carbon emission accounting method in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of biomass resource utilization technology, and in particular relates to a method for co-production of gas and carbon from flue-cured tobacco straw, synergistic carbon sequestration, and carbon emission accounting. Background Technology

[0002] Against the backdrop of global climate change, controlling carbon emissions and advancing the "dual carbon" goals have become a global consensus. Agriculture, as a significant source of carbon emissions, possesses enormous potential for emission reduction and carbon sequestration, making it a key sector for achieving these goals. Flue-cured tobacco is a core economic crop in my country, with a wide planting area and a large-scale straw production. Currently, open-air burning is the main method of tobacco straw disposal in my country, accounting for over 60%. This method not only causes a serious waste of biomass resources but also releases large amounts of... , , Greenhouse gases, such as those posed by the virus, cause a series of problems including air pollution, soil structure damage, and decreased soil fertility, which seriously restrict the sustainable development of agriculture.

[0003] Gas-to-biochar co-production technology, as a novel biomass pyrolysis utilization technology, can pyrolyze biomass under oxygen-limited conditions, simultaneously producing combustible gas (for energy utilization) and biochar (for carbon sequestration and resource utilization). It combines the dual effects of energy recovery and carbon sequestration / emission reduction, making it a core technological direction for the resource utilization of agricultural waste. However, existing technologies have the following prominent technical shortcomings in the application of flue-cured tobacco straw: 1. Insufficient adaptability of specialized technologies: The existing gas-coal cogeneration process parameters are poorly matched with the characteristics of cellulose, hemicellulose, and lignin components in flue-cured tobacco straw, making it impossible to balance the efficiency of combustible gas production and the carbon sequestration performance of biochar. The system's "energy recovery-carbon sequestration" coordinated operation capability is insufficient, and research on specialized gas-coal cogeneration technologies for flue-cured tobacco straw is extremely scarce. 2. Poor adaptability to scenarios: Existing gas-coke cogeneration equipment is mostly industrial-grade large-scale equipment with low levels of miniaturization, modularization, and intelligence. It cannot adapt to the scenarios of scattered planting in rural areas and small-scale applications in villages and towns. The equipment investment and operation and maintenance thresholds are high, making it difficult to promote on a large scale in rural areas. 3. Lack of accounting system: The existing carbon emission accounting methods for biomass gasification and biochar cogeneration systems have problems such as vague accounting boundary definition and inaccurate selection of emission factors. They generally ignore the long-term carbon sequestration effect of biochar returning to the field, and there is no dedicated full life cycle accounting model for flue-cured tobacco straw gasification and biochar cogeneration systems. It is impossible to scientifically quantify the carbon sequestration and emission reduction benefits of the system, and it is difficult to support carbon sink trading and the construction of zero-carbon villages and towns. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a method for co-production of flue-cured tobacco straw for synergistic carbon sequestration and carbon emission accounting, so as to solve the problems of poor adaptability of flue-cured tobacco straw co-production technology and lack of carbon emission accounting methods in the prior art.

[0005] The basic solution provided by this invention is a method for synergistic carbon sequestration and carbon emission accounting through co-production of flue-cured tobacco straw gas and charcoal, including: S1: After harvesting and crushing the flue-cured tobacco straw, transport it to a temporary storage warehouse using enclosed diesel freight vehicles; record the carbon emission sources from the harvesting, storage, and transportation. S2: Retrieve the harvested and crushed flue-cured tobacco straw from the temporary storage warehouse, perform vibration screening, and then use a hot air dryer for drying. After drying, the flue-cured tobacco straw is crushed a second time to 3-5mm. Finally, a mixer is used to mix the crushed flue-cured tobacco straw raw material evenly; record the carbon emission sources of the pretreatment. S3: A pyrolysis furnace is used to pyrolyze and gasify the uniformly mixed straw raw material. During the pyrolysis and gasification process, the pyrolysis temperature is controlled at 600°C. The heating rate is controlled at The oxygen volume fraction is controlled at Record the carbon emission sources from pyrolysis gasification; S4: Use a separator to separate crude biochar and mixed gas from pyrolysis gasification products and record the crude biochar yield; use a gas purification device to purify the mixed gas to obtain combustible gas and record the total combustible gas yield; and separate and recover liquid tar. S5: Call the combustible gas utilization unit for power generation and heating, and record the carbon emission source of combustible gas utilization; call the biochar utilization and carbon sequestration unit, and use a modifier to mix crude biochar with modifier for directional modification according to soil requirements. After modification, the biochar is returned to the field, and the actual amount of biochar returned to the field is recorded to characterize the core carbon sequestration source. S6: Construct a carbon emission accounting model, using the carbon emission sources from collection, storage and transportation, pretreatment, pyrolysis and gasification, combustible gas utilization and core carbon sequestration from S1-S5 as inputs to the carbon emission accounting model, and output the carbon emission accounting results.

[0006] Furthermore, S6 includes: S6-1: Based on the steps of S1-S5, extract the basic parameter system of the carbon emission accounting model, including carbon emission parameters, carbon sequestration parameters, process parameters and correlation coefficient parameters; S6-2: Based on the preset segmented carbon emission-carbon sequestration coupling calculation algorithm, the independent carbon emission of each segment is first calculated according to the basic parameter system, and then the total carbon sequestration is decomposed to each segment according to the carbon sequestration contribution coefficient. Segment-level carbon emission-carbon sequestration coupling offset is performed to obtain the coupled net carbon emission of each segment and the total net carbon emission of the system. S6-3: Based on the process parameters, establish the carbon emission coefficient and carbon sequestration factor to obtain the process parameter correction coefficient. Then, use the process parameter correction coefficient to calculate the corrected carbon emissions of each stage and the total carbon sequestration of the system under different process parameters. Substitute these into the calculation formulas for the coupled net carbon emissions of each stage and the total net carbon emissions of the system to obtain the total net carbon emissions of the system under different combinations of process parameters.

[0007] Furthermore, in S6-1, the carbon emission parameters are obtained based on the results of each step in S1-S5, specifically as follows: The carbon emission parameters for step S1 include the weight of flue-cured tobacco straw processed. Diesel consumption per unit of straw collection, storage and transportation Carbon emissions from diesel combustion ; The carbon emission parameters for step S2 include the total power consumption of the pretreatment process. Carbon emission factors of power grid ; The carbon emission parameters for step S3 include the total electricity consumption of the pyrolysis gasification process. Carbon emissions from incomplete combustion of flue-cured tobacco straw ; The carbon emission parameters for step S4 include total combustible gas emissions. ; The carbon emission parameters for step S5 include the carbon emission factor from combusted gas. ; Carbon emission parameters also include those from each stage. or Conversion Equivalent coefficient ; In S6-1, the carbon fixation parameters include the total yield of crude biochar. Biochar fixed carbon content Annual mineralization loss rate of biochar Carbon and Conversion coefficient Actual amount of biochar returned to the field ; In step S6-1, the process parameters include the particle size of the straw material in steps S1 and S2. The pyrolysis temperature of the S3 pyrolysis gasification process heating rate oxygen volume fraction ; In S6-1, the correlation coefficient parameter includes the carbon sequestration contribution coefficient of the collection, storage and transportation process. carbon sequestration contribution coefficient of pretreatment stage Carbon sequestration contribution coefficient in pyrolysis gasification process Carbon sequestration contribution coefficient in combustible gas utilization The above correlation coefficient parameters were obtained through iterative optimization based on an improved genetic algorithm.

[0008] Furthermore, in S6-2, based on a preset segmented carbon emission-carbon sequestration coupling calculation algorithm, the independent carbon emissions of each segment are first calculated according to the basic parameter system. Then, the total carbon sequestration is decomposed to each segment according to the carbon sequestration contribution coefficient, and segment-level carbon emission-carbon sequestration coupling offset is performed to obtain the net carbon emission of each segment and the total net carbon emission of the system as follows: Based on the actual carbon sequestration amount of biochar returned to the field, and after deducting mineralization losses, the total carbon sequestration amount of the system is calculated using the following expression:

[0009] in, This represents the total carbon sequestration of the system. This represents the total yield of crude biochar. To fix the carbon content in biochar; The annual mineralization loss rate of biochar; For carbon and Conversion coefficient; Carbon emissions from the four stages of collection, storage, transportation, pretreatment, pyrolysis and gasification, and combustible gas utilization should be calculated separately. , , , The expression is:

[0010] in, This indicates carbon emissions during the collection, storage, and transportation process; Indicates the processed weight of flue-cured tobacco straw; This indicates the amount of diesel fuel consumed per unit of straw collection, storage, and transportation. Indicates the carbon emission factor of diesel combustion; express or Conversion Equivalent coefficient ;

[0011] in, This indicates carbon emissions during the pretreatment process; This indicates the total power consumption of the pretreatment stage; Indicates the local power grid carbon emission factor;

[0012] in, This indicates carbon emissions during the pyrolysis and gasification process; This indicates the carbon emission factor from the incomplete combustion of flue-cured tobacco straw; This indicates the total power consumption during the pyrolysis and gasification process;

[0013] in, This indicates carbon emissions during the utilization of combustible gas; Indicates the carbon emission factor of combustible gas combustion; Total carbon sequestration in the system Based on the carbon sequestration contribution coefficient of each link in the correlation coefficient parameters , , , The carbon sequestration amount is obtained by breaking it down into each carbon emission stage. , , , Then calculate the net carbon emissions of each coupled process. , , , The expression is: ; ; ; ; in, Carbon sequestration during the collection, storage, and transportation process; This refers to the amount of carbon fixed during the pretreatment process. This refers to the amount of carbon fixed during the pyrolysis gas process. Carbon sequestration during the utilization of combustible gas; ; ; ; ; in, Couple net carbon emissions to the collection, storage, and transportation processes; To couple net carbon emissions to the pretreatment process; This is to couple net carbon emissions to the pyrolysis gas process; This is to couple net carbon emissions to the combustible gas utilization process; The total net carbon emissions of the system are calculated based on the coupling of each stage, and the expression is as follows:

[0014] in, This represents the system's total net carbon emissions.

[0015] Furthermore, in step S6-3, based on the process parameters, the carbon emission coefficient and carbon sequestration factor are quantified to obtain the process parameter correction coefficient. The corrected carbon emissions of each stage and the total carbon sequestration of the system under different process parameters are then calculated using this correction coefficient. Substituting these values ​​into the calculation formulas for the coupled net carbon emissions of each stage and the total net carbon emissions of the system, the specific total net carbon emissions of the system under different combinations of process parameters are obtained as follows: Process parameters: straw material particle size pyrolysis temperature heating rate oxygen volume fraction As dynamic input variables, a quantitative correlation is established between process parameters and carbon emission coefficients and carbon sequestration factors to obtain process parameter correction coefficients. The expression is:

[0016] in, This represents the correlation coefficient between pyrolysis temperature and carbon emission and fixation. This represents the reference value for pyrolysis temperature; This represents the correlation coefficient between the heating rate and carbon emissions and carbon sequestration. This represents the baseline value for the heating rate; This represents the correlation coefficient between oxygen volume fraction and carbon emissions and carbon sequestration. This indicates the baseline value for oxygen volume fraction; This represents the correlation coefficient between material particle size and carbon emission and carbon sequestration. Indicates the reference value for material particle size; Correction coefficient for process parameters By introducing the calculation formulas for carbon emissions at each stage and total carbon sequestration in the system, the corrected carbon emissions and total carbon sequestration under different combinations of process parameters are obtained. The expressions for the corrected carbon emissions at each stage are as follows: ; ; ; ; The revised expression for total solid carbon content in the system is:

[0017] in, , , , These represent the corrected carbon emissions from the collection, storage, and transportation process, the corrected carbon emissions from the pretreatment process, the corrected carbon emissions from the pyrolysis and gasification process, and the corrected carbon emissions from the combustible gas utilization process, respectively. This indicates the total carbon sequestration in the system after correction. Based on the corrected carbon emissions of each stage and the corrected total carbon sequestration of the system, substituting these values ​​into the calculation formulas for the coupled net carbon emissions of each stage and the total net carbon emissions of the system, the total net carbon emissions of the system under different combinations of process parameters are obtained, as expressed in the following expression:

[0018] in, This represents the corrected total net carbon emissions of the system.

[0019] Furthermore, the parameters of each correlation coefficient are obtained through iterative optimization using an improved genetic algorithm, specifically as follows: Based on the carbon sequestration contribution coefficients of each link in the correlation coefficient parameters and their constraints, an objective function for minimizing the accounting error and an objective function for maximizing the system's net emission reduction are constructed. The expression for the objective function for minimizing the accounting error is as follows:

[0020] in, This represents the calculated net emission reduction value of the system. , This represents the measured net emission reduction of the system. The objective function expression for maximizing the system's net emission reduction is:

[0021] Normalize the two objective functions to obtain the processed objective function. , Then, the adaptive weights of each objective function are dynamically calculated based on the number of iterations. , The expression is:

[0022]

[0023] in, To calculate the weights of the objective function that minimizes the accounting error, The weights of the objective function for maximizing the system's net emission reduction are given; then the fitness function expression is:

[0024] in, The fitness function; Determine whether the current iteration meets the convergence termination condition. If yes, output the optimal solution. If no, extract the global elite individuals and local elite individuals from the current population. The global elite individuals are directly copied to the next iteration, and the local elite individuals are stored in the elite pool. The tournament selection method is used to randomly select k individuals from the population, and the individual with the smallest fitness value is selected to enter the crossover stage; Simulated binary crossover is employed, based on a preset adaptive crossover probability operator. New individuals are generated by randomly selecting one individual from the elite pool for crossover, using a preset adaptive crossover probability operator. The expression is:

[0025] in, , represent the upper and lower bounds of the crossover probability, respectively. The smaller fitness value among the two individuals to be crossed. This represents the average fitness value of the current population. This represents the minimum fitness value of the current population. Polynomial mutation is employed, based on a pre-defined adaptive mutation probability operator. For new individual gene perturbations, genes exceeding the range are corrected according to corresponding constraints, using a pre-defined adaptive mutation probability operator. The expression is:

[0026] in, , These represent the upper and lower limits of the mutation probability. The fitness value of the individual to be mutated; The new individuals generated through crossover and mutation are combined with the global elite individuals to form a new generation of population, and fitness values ​​are calculated. After iterative convergence, the result with the minimum fitness value in the population is output, and the optimal carbon fixation contribution coefficient set is obtained after decoding. ; The decoded optimal carbon sequestration contribution coefficient set is substituted into the carbon emission accounting model for verification. After verification, it is directly input into the carbon emission accounting model for accounting. Real-time monitoring of process parameter correction coefficients The range of change, if If the change exceeds the preset change threshold, the improved genetic algorithm will be directly triggered to iterate again to obtain the optimal set of carbon fixation contribution coefficients adapted to the new process parameters.

[0027] Furthermore, S5 includes: S5-1: The combustible gas obtained in step S4 is transported to the combustible gas utilization unit through a sealed insulated pipeline. It is then divided into two paths by a branch regulating valve, one path being transported to the gas power generation module and the other path being transported to the gas heating module. S5-2: The crude biochar obtained from step S4 is transported to the raw material buffer bin of the biochar utilization and carbon fixation unit. Metal impurities in the crude biochar are removed by magnetic separation equipment, and fine powder biochar with a particle size of less than 1 mm and coarse block biochar with a particle size of more than 20 mm are removed by screening equipment, leaving uniform crude biochar raw material with a particle size of 1-20 mm. S5-3: Based on the soil requirements of the flue-cured tobacco planting area, a modifier is used to perform targeted modification of the crude biochar; S5-4: Apply the modified biochar evenly to the surface of the flue-cured tobacco planting field and till the soil to fully mix the biochar with the topsoil. S5-5: Record the actual amount of biochar returned to the field and the carbon emission sources from combustible gas utilization.

[0028] The principles and advantages of this invention are as follows: Firstly, based on the principles of biomass pyrolysis and gasification conversion, and the principles of graded utilization and storage of carbon elements, a fully closed-loop technical system encompassing process implementation, product utilization, carbon flow tracking, and precise accounting is constructed. Secondly, using flue-cured tobacco straw as raw material, a continuous process of graded pretreatment, precise pyrolysis, and product purification is employed to utilize biomass at 600... The thermochemical transformation characteristics under oxygen-limited conditions break the original chemical bond structure of cellulose, hemicellulose, and lignin in straw. Through a combination of separation, recovery, and adsorption processes, the crude biochar, combustible gas, and liquid tar are efficiently separated, laying the material foundation for subsequent high-value utilization and carbon sequestration. Next, the purified combustible gas is used to replace fossil fuels for power generation and heating, reducing carbon emissions from fossil fuel combustion and achieving carbon sequestration through substitution and emission reduction. The crude biochar from the pyrolysis products is then directionally modified and returned to the field. Utilizing the stability of the aromatic carbon structure of biochar, carbon elements are retained in the soil for a long time, achieving carbon sink-type carbon sequestration. Finally, the carbon emission sources and carbon sequestration sources in each of the above steps are tracked throughout the entire process. An improved genetic algorithm is used to calculate the carbon sequestration contribution coefficient of each step. The dynamically solved contribution coefficient is coupled with the carbon flow data of each step, combined with a linkage mechanism of process parameter correction coefficients, to achieve accurate calculation of the system's net emission reduction, ensuring a high degree of matching between the calculation results and actual process conditions.

[0029] The advantages are: 1. Advantages of technological innovation: On the one hand, it changes the traditional single mode of "direct combustion for power generation" and "simple return to the field" of flue-cured tobacco straw, and realizes the full-component cascade utilization of "biochar carbon fixation + combustible gas energy + tar chemical raw materials" through pyrolysis and gasification, thereby improving the comprehensive utilization rate of straw; on the other hand, it standardizes core parameters such as pyrolysis temperature, heating rate, and oxygen volume fraction, and combines "secondary crushing" and "waste heat drying" processes in the pretreatment stage to ensure stable pyrolysis reaction and uniform product quality, thus solving the pain points of low product yield and large quality fluctuations in traditional processes. 2. Improved carbon sequestration efficiency: On the one hand, it simultaneously achieves "dynamic emission reduction by replacing fossil energy with combustible gas" and "static storage of biochar by returning it to the field." Compared with the traditional direct return of straw to the field, the carbon sequestration efficiency of the biochar returned to the field after targeted modification is improved. Compared to direct straw combustion, this invention uses biochar to long-term sequester carbon, increasing the annual carbon sequestration by 50-80 kg of CO2 equivalent per acre of flue-cured tobacco field. This data was verified by comparative experiments on three groups of flue-cured tobacco planting plots, and is the average value measured over two consecutive years. On the other hand, the coarse biochar is modified in a targeted manner according to the soil requirements for flue-cured tobacco planting, which not only improves the soil improvement effect of biochar but also strengthens the stability of carbon sequestration, achieving a win-win situation of "carbon sequestration + increased agricultural production". 3. Advantages of the accounting technology: On the one hand, the improved genetic algorithm's encoding method, fitness function, and genetic operators are all designed specifically for the characteristics of flue-cured tobacco straw gas-carbon cogeneration process, solving the problems of standard algorithms easily generating invalid solutions and premature convergence, and significantly improving the accuracy of the carbon fixation contribution coefficient calculation; on the other hand, a linkage mechanism for process parameter correction coefficients is introduced. When process parameters such as pyrolysis temperature and heating rate change, the coefficients are automatically updated, realizing a complete closed loop of "process condition change - carbon flow data update - accounting coefficient optimization", solving the problem of the traditional accounting model being disconnected from the process. Attached Figure Description

[0030] Figure 1 This is a flowchart of an embodiment of the present invention. Detailed Implementation

[0031] The following detailed description illustrates the specific implementation method: The basic implementation examples are as follows: Figure 1 As shown: the method for synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gasification and charcoal production includes: S1: After harvesting and crushing the flue-cured tobacco straw, transport it to a temporary storage warehouse using enclosed diesel freight vehicles; record the carbon emission sources during harvesting, storage, and transportation; specifically: After the flue-cured tobacco has matured and been harvested, a mobile field straw crusher is used directly in the field to simultaneously harvest and initially crush the tobacco straw. The gap between the crusher's blades is adjusted to 10-20mm, so that the tobacco straw is crushed into straw fragments with a particle size of 10-20mm. This particle size avoids the problems of tangling and accumulation during transportation caused by excessively long straw, and also reduces the energy consumption of secondary crushing in subsequent pretreatment stages. During the harvesting and crushing process, it is ensured that the straw fragments are free from obvious mold and impurities. Soil, stones, and substandard tobacco leaves and other non-straw impurities are removed from the straw to ensure the basic quality of the raw materials.

[0032] Next, the crushed tobacco straw from the field is transferred using enclosed diesel freight vehicles. The cargo compartments of these vehicles are equipped with sealed anti-scattering covers, which are kept closed throughout the transportation process to prevent straw fragments from scattering and to avoid dust pollution. Considering the dispersed layout of tobacco planting villages and towns, the transportation radius is controlled within 5km to meet the raw material supply needs of village and town-level tobacco straw processing. Before transportation, the cargo compartments of the vehicles are cleaned to prevent foreign pollutants from mixing into the straw raw materials. After transportation, the weight of straw fragments and the total diesel consumption for each trip are recorded.

[0033] Finally, the tobacco straw fragments transported to the designated site are placed in a ventilated and moisture-proof steel structure temporary storage warehouse for standardized temporary storage. The warehouse is equipped with tiered material stacking racks, with the straw fragments stacked no more than 2.5m high and spaced at least 0.5m apart to ensure air circulation. Temperature and humidity monitoring sensors are installed inside the warehouse to monitor the ambient temperature and humidity in real time. The forced ventilation system regulates the internal humidity to ensure the moisture content of the tobacco straw fragments is stably controlled within a certain range. Within this range, it is necessary to prevent straw fragments from becoming moldy or rotten during temporary storage, and to ensure the stability of raw material supply for subsequent pyrolysis and gasification processes.

[0034] During the above process, carbon emission data for the collection, storage, and transportation stages are simultaneously completed, including the weight of flue-cured tobacco straw processed. Diesel consumption per unit of straw collection, storage and transportation Carbon emissions from diesel combustion It serves as the sole input for carbon emission parameters in the storage and transportation stages of the S6 stage carbon emission accounting model.

[0035] S2: Retrieve harvested and shredded tobacco straw from the temporary storage warehouse, perform vibration screening, and then dry it using a hot air dryer. After drying, the tobacco straw is shredded a second time to 3-5mm. Finally, the shredded tobacco straw is mixed evenly. Record the pretreatment carbon emission sources. Specifically: First, a quantitative amount of harvested and pulverized flue-cured tobacco straw is quantitatively retrieved from the ventilated and moisture-proof steel structure temporary storage warehouse in step S1 via a belt conveyor. The raw material is continuously conveyed to a ZS-515 vibrating screen for vibration screening. The vibrating screen is equipped with upper and lower double-layer screens; the upper screen has an aperture of 25mm, and the lower screen has an aperture of 8mm. The screen vibration frequency is adjusted to 30Hz. Vibration screening removes inorganic impurities such as soil, stones, and tobacco roots, as well as moldy and clumped straw, ensuring a high impurity removal rate. The qualified flue-cured tobacco straw raw materials after screening are transported to the subsequent drying process through a feeding chute. The impurities screened out are collected and treated in a harmless manner to avoid mixing into the subsequent processes and affecting the product quality and equipment operation stability.

[0036] Next, the qualified flue-cured tobacco straw raw material after vibration screening is conveyed to a CT-C-1 type hot air dryer for continuous drying. The dryer adopts a co-current drying process, and the hot air temperature is controlled at [temperature range missing]. The residence time of the raw materials in the dryer is adjusted to 40-60 minutes. The hot air source for the dryer is provided by the waste heat from the pyrolysis furnace in the subsequent S3 pyrolysis and gasification stage. The high-temperature flue gas generated by the pyrolysis furnace is introduced into the hot air generator of the dryer through the waste heat recovery pipeline, realizing the utilization of waste heat resources without additional fossil fuel consumption. During the drying process, the moisture content of the straw raw materials is monitored in real time by an online moisture content detection device at the dryer outlet. The moisture content of the raw materials is adjusted from the moisture content after temporary storage in S1. Precisely reduced to The dried straw raw material is cooled to room temperature in the cooling section and then transported to the secondary crushing process to meet the moisture content requirements of the subsequent secondary crushing and pyrolysis gasification process.

[0037] The dried and cooled tobacco straw is then fed into a 9FQ-400 hammer mill for secondary crushing. The mill is equipped with wear-resistant alloy hammers and a grading screen with a mesh size of 3-5mm. The main shaft speed of the mill is adjusted to... The crusher uses hammering and shearing to pulverize straw raw materials into uniform 3-5mm straw powder. During the pulverizing process, the crusher is equipped with a negative pressure dust removal device to collect the straw dust generated during pulverization, preventing dust from escaping and causing air pollution. The collected straw dust is centrally recycled and remixed into the straw powder to improve the utilization rate of raw materials. The straw powder after secondary pulverization is transported to the mixing process through a closed pipeline to ensure that the particle size of the powder meets the heat and mass transfer efficiency requirements of the pyrolysis and gasification process, while also taking into account the energy consumption economy of the pulverizing process.

[0038] Finally, the 3-5mm straw powder after secondary crushing is conveyed to a horizontal ribbon mixer for homogenization and mixing. The effective volume of the mixer is [missing information]. The spindle speed is adjusted to The single mixing loading is 600 kg, and the mixing time is set to 15 min. Through the pushing and stirring action of the screw conveyor, the flue-cured tobacco straw powder from different batches and parts is mixed evenly, eliminating local differences in raw material composition and particle size, and ensuring the consistency of reaction conditions and the stability of product yield and quality in the subsequent S3 pyrolysis and gasification process. The standardized flue-cured tobacco straw raw material after being mixed evenly is temporarily stored in the raw material buffer silo. The buffer silo is equipped with a material level monitoring device to achieve continuous and quantitative supply of raw materials for the S3 pyrolysis and gasification process, completing all process operations in the pretreatment stage.

[0039] During step S2 above, the carbon emission sources recorded include the total power consumption of the pretreatment process. Carbon emission factors of power grid ,as well as or Conversion Equivalent coefficient All recorded carbon emission source data from the pretreatment stage are entered into a dedicated data acquisition system for co-production of flue-cured tobacco straw gas and carbon sequestration and carbon emission accounting. After data entry, it is double-checked to ensure that there are no missing items, no errors, and no duplications. After the check is passed, the data is classified and archived, serving as the sole input basis for the carbon emission parameters of the pretreatment stage in the S6 stage carbon emission accounting model, thereby achieving synchronization and standardization of the pretreatment stage process operation and carbon emission source data acquisition.

[0040] S3: A pyrolysis furnace is used to pyrolyze and gasify the uniformly mixed straw raw material. During the pyrolysis and gasification process, the pyrolysis temperature is controlled at 600°C. The heating rate is controlled at The oxygen volume fraction is controlled at Record the carbon emission sources from pyrolysis gasification; specifically: First, a belt feeder continuously and quantitatively extracts uniformly mixed 3-5mm flue-cured tobacco straw powder from the raw material buffer bin in step S2. The feeder's feeding rate is adjusted to 40-50. The feed is designed to match the capacity of the pyrolysis furnace. Raw materials are transported to the furnace inlet via a closed-loop feeding pipeline equipped with a blockage monitoring device to monitor the feed status in real time, preventing interruptions in the pyrolysis furnace feed due to pipeline blockage and ensuring the continuous and stable operation of the pyrolysis gasification reaction. Before feeding, the furnace cavity is purged with inert gas (nitrogen) to pre-reduce the oxygen volume fraction within the furnace cavity to a level that is compatible with the furnace's design capacity. The following lays the foundation for subsequent oxygen-limited pyrolysis reactions.

[0041] Next, the FY-1000 type small fixed-bed pyrolysis furnace was used as the core reaction equipment. The effective volume of this pyrolysis furnace is... Suitable for the scale of flue-cured tobacco straw processing in villages and towns, the furnace body is equipped with a thickened aluminum silicate insulation layer with a thickness of not less than 100mm to reduce heat loss and ensure a stable temperature field inside the furnace. The pyrolysis furnace is equipped with a temperature control system, an oxygen regulation system, and a pressure monitoring system. Each system is debugged before formal feeding. Temperature control system debugging: Adjust the temperature control accuracy of the intelligent temperature controller of the pyrolysis furnace to [the appropriate level]. Preset pyrolysis target temperature heating rate To verify the linkage response between the temperature controller and the furnace heating element; Oxygen regulation system debugging: Adjust the flow regulation accuracy of the small air flow meter of the pyrolysis furnace to [value missing]. Preset range for adjusting oxygen volume fraction in the furnace To verify the coordinated controllability of the flow meter and the furnace inlet valve; Pressure monitoring system debugging: Adjust the monitoring range of the furnace pressure monitor to... The alarm threshold is set to This ensures that an alarm can be triggered promptly and the overpressure relief device can be activated when the pressure inside the furnace is abnormal.

[0042] Finally, after the quantitatively delivered flue-cured tobacco straw powder is fed into the preheated pyrolysis furnace chamber, the pyrolysis and gasification reaction program is started. The entire process is precisely controlled according to the preset process parameters to ensure that the reaction process conforms to the pyrolysis law of the flue-cured tobacco straw component characteristics. Heating phase control: The power of the furnace heating elements is controlled by the temperature control system to achieve the desired heating effect. A constant heating rate raises the furnace temperature from room temperature to During the heating process, the temperature values ​​of different areas inside the furnace are monitored in real time to ensure a uniform temperature field and a temperature difference not exceeding [a certain value]. ; Isothermal pyrolysis stage control: furnace temperature reaches Afterwards, the pyrolysis is maintained at a constant temperature, while a precise metered amount of air is precisely introduced into the furnace through the oxygen regulation system to stably control the oxygen volume fraction inside the furnace. This achieves oxygen-limited pyrolysis of tobacco straw, preventing complete combustion; the pressure inside the furnace is maintained at a constant temperature during the isothermal pyrolysis stage. This ensures that the mixed gas generated by the pyrolysis reaction is stably discharged, and that the reaction duration matches the raw material feeding rate, thus ensuring the complete pyrolysis of straw powder. During the pyrolysis and gasification process, the flue-cured tobacco straw undergoes staged pyrolysis, successively completing the drying, main pyrolysis and carbonization reactions, simultaneously producing crude biochar, combustible gas and liquid tar mixture. The reaction products are discharged through the char outlet at the bottom of the furnace and the gas outlet at the top, respectively, and enter the subsequent S4 product separation and purification stage.

[0043] During step S3 above, the carbon emission sources recorded include the total electricity consumption of the pyrolysis gasification process. Carbon emissions from incomplete combustion of flue-cured tobacco straw Carbon emission factors of power grid The value is consistent with that of step S2; and or Conversion Equivalent coefficient ; All recorded carbon emission source data from the pyrolysis gasification process are entered into a dedicated data acquisition system for the synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gasification and carbon sequestration. After data entry, it is double-checked to ensure that there are no missing items, no errors, and no duplications. After the check is passed, the data is classified and archived, serving as the sole input basis for the carbon emission parameters of the pyrolysis gasification process in the S6 process carbon emission accounting model, thereby achieving synchronization and standardization of the pyrolysis gasification process operation and carbon emission source data acquisition.

[0044] S4: A separator is used to separate crude biochar and mixed gas from the pyrolysis gasification products, and the crude biochar yield is recorded; a gas purification device is used to purify the mixed gas to obtain combustible gas, and the total combustible gas yield is recorded; and liquid tar is separated and recovered; specifically: First, the mixture of crude biochar, combustible gas, and liquid tar continuously discharged from the S3 pyrolysis gasification furnace is transported through a sealed, insulated pipeline to a CLT / A-100 cyclone separator for efficient solid-gas separation; the inlet velocity of the separator is adjusted to... The separator utilizes centrifugal force to separate coarse biochar particles from the gas phase in the mixed gas. The separated coarse biochar is continuously discharged from the closed-loop discharger at the bottom of the separator. The discharge frequency of the closed-loop discharger is matched with the feed rate of the pyrolysis furnace to ensure that there is no gas leakage due to entrainment in the coarse biochar, thus maximizing the solid-gas separation efficiency of the separator. .

[0045] After the crude biochar is discharged, its weight is measured in real time using a belt weighing scale, with a measurement accuracy of [insert accuracy here]. The total crude biochar production in a single batch / cycle is accurately recorded in kilograms. The recorded data is uploaded to a dedicated data acquisition system in real time. The separated combustible gas and liquid tar mixture is discharged from the top outlet of the separator and transported to the subsequent gas purification process through a closed pipeline. During the separation process, the separator is equipped with a negative pressure monitoring device to ensure that the system operates under slight negative pressure and that no mixture escapes. Next, the combustible gas and liquid tar mixture after solid-gas separation is transported to an XSC-500 activated carbon adsorption tower for deep purification. The adsorption tower is filled with columnar activated carbon adsorbent with a particle size of 3-5mm. The empty gas velocity of the mixture in the adsorption tower is adjusted to... Duration of stay Activated carbon removes impurities such as tar droplets and dust from the gas mixture through physical adsorption, thus purifying the combustible gas and reducing its impurity content. ,purity This meets the combustion requirements for subsequent power generation and heating.

[0046] The purified combustible gas is flowed using a Roots flow meter, with a measurement accuracy of [insert accuracy here]. Accurately record the total output of combustible gas in a single cycle, measured in cubic meters. The recorded data is uploaded to a dedicated data acquisition system in real time and archived in conjunction with the crude biochar production data. The activated carbon adsorption tower is equipped with an adsorbent replacement reminder device. When the adsorbent is saturated, it should be replaced in time to ensure stable gas purification effect. The replaced waste activated carbon can be mixed with crude biochar for subsequent modification treatment to achieve resource reuse.

[0047] Finally, an LN-200 indirect condenser tar recovery unit is installed before the mixed gas purification process to condense the mixed gas after solid-gas separation, achieving efficient separation and recovery of liquid tar. The tar recovery unit adopts an indirect condensation process using cooling water, with the condensate temperature controlled at [temperature range missing]. The condensation temperature of the gas mixture in the recovery unit drops to The liquid tar droplets in the gas mixture condense into liquid tar, which is then collected in a tar storage tank at the bottom of the recoverer by gravity settling. This process achieves a high tar recovery efficiency. .

[0048] S5: Utilize the combustible gas utilization unit for power generation and heating, and record the carbon emission sources from combustible gas utilization; utilize the biochar utilization and carbon sequestration unit to modify the crude biochar according to soil requirements, and then return the modified biochar to the field, recording the actual amount of biochar returned to the field to characterize the core carbon sequestration source; S5 includes: S5-1: The combustible gas obtained in step S4 is transported to the combustible gas utilization unit through a sealed, insulated pipeline. It is then divided into two streams by a regulating valve: one stream goes to the gas-fired power generation module, and the other goes to the gas-fired heating module. The flow distribution ratio between the two streams is dynamically adjusted according to the actual electricity and heating needs of the village / town. The total transport flow rate is kept in balance with the total combustible gas production in step S4. The pipeline is equipped with a pressure stabilizing device to maintain the combustible gas transport pressure at a certain level. This ensures the stable operation of the power generation and heating modules.

[0049] In the entire process of combustible gas power generation and heating, the online equipment monitoring and data acquisition system completes the real-time and accurate recording of carbon emission sources from combustible gas utilization. The recorded data serves as the core input parameter for the S6 carbon emission accounting model, ensuring the data's authenticity, completeness, and traceability. Specific recorded content includes: carbon emission factors from combustible gas combustion. , or Conversion Equivalent coefficient ; S5-2: The crude biochar obtained from step S4 is transported to the raw material buffer bin of the biochar utilization and carbon fixation unit. Metal impurities in the crude biochar are removed by magnetic separation equipment, and fine powder biochar with a particle size of less than 1 mm and coarse block biochar with a particle size of more than 20 mm are removed by screening equipment, leaving uniform crude biochar raw material with a particle size of 1-20 mm. S5-3: Based on the soil requirements of the tobacco planting area, a modifying machine is used to perform targeted modification treatment on the crude biochar; for example, a JBM-500 type stirred modifying machine is used for targeted modification treatment of crude biochar, with an effective volume of [missing information]. spindle speed The specific modification process is adapted to soil requirements: if the soil is acidic, add an appropriate amount of alkaline mineral powder to the modifyer and mix with coarse biochar to enhance the acid-base regulation capacity of the biochar; if the soil has low organic matter content, add an appropriate amount of well-rotted organic fertilizer to the coarse biochar and mix with it to strengthen the soil fertility-enhancing effect of the biochar; the modification treatment time is set to... The high-speed stirring of the modifier achieves uniform mixing of crude biochar and modifier, and the modified biochar has stronger soil improvement and carbon sequestration performance.

[0050] S5-4: Apply the modified biochar evenly to the surface of the flue-cured tobacco planting field and till the soil to fully mix the biochar with the topsoil. S5-5: Record the actual amount of biochar returned to the field and the carbon emission sources from combustible gas utilization; including the actual amount of biochar returned to the field. Biochar fixed carbon content Annual mineralization loss rate of biochar Carbon and Conversion coefficient ; S6: Construct a carbon emission accounting model, using the carbon emission sources from collection, storage, and transportation, pretreatment, pyrolysis and gasification, combustible gas utilization, and core carbon sequestration as inputs to the model, and outputting carbon emission accounting results; where S6 includes: S6-1: Based on the steps in S1-S5, extract the basic parameter system for the carbon emission accounting model, including carbon emission parameters, carbon sequestration parameters, process parameters, and correlation coefficient parameters; among which, the carbon emission parameters are obtained based on the steps in S1-S5, specifically as follows: The carbon emission parameters for step S1 include the weight of flue-cured tobacco straw processed. Diesel consumption per unit of straw collection, storage and transportation Carbon emissions from diesel combustion ; The carbon emission parameters for step S2 include the total power consumption of the pretreatment process. Carbon emission factors of power grid ; The carbon emission parameters for step S3 include the total electricity consumption of the pyrolysis gasification process. Carbon emissions from incomplete combustion of flue-cured tobacco straw ; The carbon emission parameters for step S4 include total combustible gas emissions. ; The carbon emission parameters for step S5 include the carbon emission factor from combusted gas. ; Carbon emission parameters also include those from each stage. or Conversion Equivalent coefficient ; In S6-1, the carbon fixation parameters include the total yield of crude biochar. Biochar fixed carbon content Annual mineralization loss rate of biochar Carbon and Conversion coefficient Actual amount of biochar returned to the field ; In S6-1, the process parameters include the particle size of the straw material in steps S1 and S2. The pyrolysis temperature of the S3 pyrolysis gasification process heating rate oxygen volume fraction ; In S6-1, the correlation coefficient parameters include the carbon sequestration contribution coefficient of the collection, storage, and transportation stages. carbon sequestration contribution coefficient of pretreatment stage Carbon sequestration contribution coefficient in pyrolysis gasification process Carbon sequestration contribution coefficient in combustible gas utilization The above correlation coefficient parameters are obtained through iterative optimization based on an improved genetic algorithm; specifically: Based on the carbon sequestration contribution coefficients of each link in the correlation coefficient parameters and their constraints, an objective function for minimizing the accounting error and an objective function for maximizing the system's net emission reduction are constructed. The expression for the objective function for minimizing the accounting error is as follows:

[0051] in, This represents the calculated net emission reduction value of the system. , This represents the measured net emission reduction of the system. The objective function expression for maximizing the system's net emission reduction is:

[0052] The constraints include mathematical hard constraints and carbon flow physical constraints. The mathematical hard constraints are: , , , All values ​​are greater than or equal to 0, and their sum is 1; simultaneously, physical constraints on carbon flow are constructed based on the contribution levels of different stages, specifically:

[0053] Simultaneously, mathematical hard constraints and carbon flow physical constraints are directly embedded into the coding structure, employing a 3D independent variable coding method combined with a 4D constraint derivation method. , , , Encode, where: Chromosome coding structure: The four coefficients are encoded into a real chromosome of length 3, and the gene values ​​directly match the physical constraints. ,in, ; ; ; Derivation of the fourth-dimensional constraint: Derived from the first three coefficients, it satisfies ; Normalize the two objective functions to obtain the processed objective function. , Then, the adaptive weights of each objective function are dynamically calculated based on the number of iterations. , The expression is:

[0054]

[0055] in, To calculate the weights of the objective function that minimizes the accounting error, The weights of the objective function for maximizing the system's net emission reduction are given; then the fitness function expression is:

[0056] in, The fitness function; Determine whether the current iteration meets the convergence termination condition. If yes, output the optimal solution. If no, extract the global elite individuals and local elite individuals from the current population. The global elite individuals are directly copied to the next iteration, and the local elite individuals are stored in the elite pool. The tournament selection method is used to randomly select k individuals from the population, and the individual with the lowest fitness value is selected to enter the crossover stage; in this embodiment, k=5. Simulated binary crossover is employed, based on a preset adaptive crossover probability operator. New individuals are generated by randomly selecting one individual from the elite pool for crossover, using a preset adaptive crossover probability operator. The expression is:

[0057] in, , These represent the upper and lower bounds of the crossover probability, respectively, in this embodiment. , , The smaller fitness value among the two individuals to be crossed. This represents the average fitness value of the current population. This represents the minimum fitness value of the current population. Polynomial mutation is employed, based on a pre-defined adaptive mutation probability operator. For new individual gene perturbations, genes exceeding the range are corrected according to corresponding constraints, using a pre-defined adaptive mutation probability operator. The expression is:

[0058] in, , In this embodiment, the upper and lower limits of the mutation probability are defined. , , The fitness value of the individual to be mutated; The new individuals generated through crossover and mutation are combined with the global elite individuals to form a new generation of population, and fitness values ​​are calculated. After iterative convergence, the result with the minimum fitness value in the population is output, and the optimal carbon fixation contribution coefficient set is obtained after decoding. In this embodiment, the genetic algorithm population size is set to 100, the maximum number of iterations is 200, and the iteration convergence is determined when the fitness value change rate is less than or equal to 0.001 for 20 consecutive iterations.

[0059] The decoded optimal carbon sequestration contribution coefficient set is substituted into the carbon emission accounting model for verification. After verification, it is directly input into the carbon emission accounting model for accounting. Real-time monitoring of process parameter correction coefficients The range of change, if If the change exceeds a preset threshold, such as 5%, the improved genetic algorithm is directly triggered to iterate again, obtaining the optimal set of carbon fixation contribution coefficients adapted to the new process parameters; process parameter correction coefficients The calculation method is to use the process parameter straw particle size pyrolysis temperature heating rate oxygen volume fraction As dynamic input variables, a quantitative correlation is established between process parameters and carbon emission coefficients and carbon sequestration factors to obtain process parameter correction coefficients. The expression is:

[0060] in, The coefficient representing the correlation between pyrolysis temperature and carbon emission and fixation is 0.08 in this example. This represents the reference value for pyrolysis temperature; The coefficient representing the correlation between the heating rate and carbon emissions / carbon sequestration is 0.06 in this embodiment. This represents the baseline value for the heating rate; The coefficient representing the correlation between oxygen volume fraction and carbon emissions and carbon sequestration is 0.12 in this embodiment. This indicates the baseline value for oxygen volume fraction; This represents the correlation coefficient between material particle size and carbon emission and carbon fixation; in this example, it is 0.04. Indicates the reference value for material particle size; S6-2: Based on a pre-defined segmented carbon emission-carbon sequestration coupling calculation algorithm, the independent carbon emissions of each segment are first calculated according to the basic parameter system. Then, the total carbon sequestration is decomposed into each segment according to the carbon sequestration contribution coefficient, and segment-level carbon emission-carbon sequestration coupling offset is performed to obtain the coupled net carbon emissions of each segment and the total net carbon emissions of the system; specifically: Based on the actual carbon sequestration amount of biochar returned to the field, and after deducting mineralization losses, the total carbon sequestration amount of the system is calculated using the following expression:

[0061] in, This represents the total carbon sequestration of the system. This represents the total yield of crude biochar. To fix the carbon content in biochar; The annual mineralization loss rate of biochar; For carbon and Conversion coefficient; Carbon emissions from the four stages of collection, storage, transportation, pretreatment, pyrolysis and gasification, and combustible gas utilization should be calculated separately. , , , The expression is:

[0062] in, This indicates carbon emissions during the collection, storage, and transportation process; Indicates the processed weight of flue-cured tobacco straw; This indicates the amount of diesel fuel consumed per unit of straw collection, storage, and transportation. Indicates the carbon emission factor of diesel combustion; express or Conversion The equivalent coefficient is 0.005 in this embodiment;

[0063] in, This indicates carbon emissions during the pretreatment process; This indicates the total power consumption of the pretreatment stage; Indicates the local power grid carbon emission factor;

[0064] in, This indicates carbon emissions during the pyrolysis and gasification process; This indicates the carbon emission factor from the incomplete combustion of flue-cured tobacco straw; This indicates the total power consumption during the pyrolysis and gasification process;

[0065] in, This indicates carbon emissions during the utilization of combustible gas; Indicates the carbon emission factor of combustible gas combustion; Total carbon sequestration in the system Based on the carbon sequestration contribution coefficient of each link in the correlation coefficient parameters , , , The carbon sequestration amount is obtained by breaking it down into each carbon emission stage. , , , Then calculate the net carbon emissions of each coupled process. , , , The expression is: ; ; ; ; in, Carbon sequestration during the collection, storage, and transportation process; This refers to the amount of carbon fixed during the pretreatment process. This refers to the amount of carbon fixed during the pyrolysis gas process. Carbon sequestration during the utilization of combustible gas; ; ; ; ; in, Couple net carbon emissions to the collection, storage, and transportation processes; To couple net carbon emissions to the pretreatment process; This is to couple net carbon emissions to the pyrolysis gas process; This is to couple net carbon emissions to the combustible gas utilization process; The total net carbon emissions of the system are calculated based on the coupling of each stage, and the expression is as follows:

[0066] in, This represents the system's total net carbon emissions.

[0067] S6-3: Based on the process parameters and the quantification of carbon emission coefficients and carbon sequestration factors, process parameter correction coefficients are obtained. These correction coefficients are then used to calculate the corrected carbon emissions of each stage and the total carbon sequestration of the system under different process parameters. Substituting these coefficients into the formulas for calculating the coupled net carbon emissions of each stage and the total net carbon emissions of the system, the total net carbon emissions of the system under different combinations of process parameters are obtained. Specifically: Process parameters: straw material particle size pyrolysis temperature heating rate oxygen volume fraction As dynamic input variables, a quantitative correlation is established between process parameters and carbon emission coefficients and carbon sequestration factors to obtain process parameter correction coefficients. The expression is:

[0068] in, The coefficient representing the correlation between pyrolysis temperature and carbon emission and fixation is 0.08 in this example. This indicates the baseline value for pyrolysis temperature, which is 600 degrees Celsius. The coefficient representing the correlation between the heating rate and carbon emissions / carbon sequestration is 0.06 in this embodiment. This represents the baseline value for the heating rate. ; The coefficient representing the correlation between oxygen volume fraction and carbon emissions and carbon sequestration is 0.12 in this embodiment. The reference value for oxygen volume fraction is: ; This represents the correlation coefficient between material particle size and carbon emission and carbon fixation; in this example, it is 0.04. This indicates the standard particle size value for the material, which is 4 mm. Correction coefficient for process parameters By introducing the calculation formulas for carbon emissions at each stage and total carbon sequestration in the system, the corrected carbon emissions and total carbon sequestration under different combinations of process parameters are obtained. The expressions for the corrected carbon emissions at each stage are as follows: ; ; ; ; The revised expression for total solid carbon content in the system is:

[0069] in, , , , These represent the corrected carbon emissions from the collection, storage, and transportation process, the corrected carbon emissions from the pretreatment process, the corrected carbon emissions from the pyrolysis and gasification process, and the corrected carbon emissions from the combustible gas utilization process, respectively. This indicates the total carbon sequestration in the system after correction. Based on the corrected carbon emissions of each stage and the corrected total carbon sequestration of the system, substituting these values ​​into the calculation formulas for the coupled net carbon emissions of each stage and the total net carbon emissions of the system, the total net carbon emissions of the system under different combinations of process parameters are obtained, as expressed in the following expression:

[0070] in, This represents the corrected total net carbon emissions of the system.

[0071] After completing the above accounting process, the system automatically outputs a standardized accounting result report, the core contents of which include: Basic Parameter Summary Table: Lists the optimized results of measured parameters and correlation coefficients for each stage from S1 to S5; Detailed breakdown of carbon emissions and carbon sequestration by stage: carbon emissions at each stage, allocated carbon sequestration, and coupled net carbon emissions data; Total net carbon emissions of the system: Total net carbon emissions (net emission reductions) under baseline process parameters and dynamic accounting results under different combinations of process parameters.

[0072] Therefore, this step, through the deep integration of the three-level accounting model and the measured data, achieves the accurate quantification of carbon emissions and carbon sequestration and emission reduction benefits of the flue-cured tobacco straw gas-coal cogeneration system. The accounting process relies entirely on the measured data of S1-S5, without any generalized assumptions, and the results have strong credibility and engineering applicability. They can directly support practical application scenarios such as carbon sink trading, project acceptance, and policy application, while providing a scientific quantitative tool for the continuous optimization of technology and processes.

[0073] The above are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gasification and charcoal production, characterized in that: include: S1: After harvesting and crushing the flue-cured tobacco straw, transport it to a temporary storage warehouse using enclosed diesel freight vehicles; record the carbon emission sources from the harvesting, storage, and transportation. S2: Retrieve the harvested and crushed flue-cured tobacco straw from the temporary storage warehouse, perform vibration screening, and then use a hot air dryer for drying. After drying, the flue-cured tobacco straw is crushed a second time to 3-5mm. Finally, the crushed flue-cured tobacco straw raw material is mixed evenly; record the carbon emission sources of the pretreatment. S3: A pyrolysis furnace is used to pyrolyze and gasify the uniformly mixed straw raw material. During the pyrolysis and gasification process, the pyrolysis temperature is controlled at 600°C. The heating rate is controlled at The oxygen volume fraction is controlled at Record the carbon emission sources from pyrolysis gasification; S4: Use a separator to separate crude biochar and mixed gas from pyrolysis gasification products and record the crude biochar yield; use a gas purification device to purify the mixed gas to obtain combustible gas and record the total combustible gas yield; and separate and recover liquid tar. S5: Call the combustible gas utilization unit for power generation and heating, and record the carbon emission source of combustible gas utilization; call the biochar utilization and carbon sequestration unit, and use a modifier to mix crude biochar with modifier for directional modification according to soil requirements. After modification, the biochar is returned to the field, and the actual amount of biochar returned to the field is recorded to characterize the core carbon sequestration source. S6: Construct a carbon emission accounting model, using the carbon emission sources from collection, storage and transportation, pretreatment, pyrolysis and gasification, combustible gas utilization and core carbon sequestration from S1-S5 as inputs to the carbon emission accounting model, and output the carbon emission accounting results.

2. The method for synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gas co-production according to claim 1, characterized in that: S6 includes: S6-1: Based on the steps of S1-S5, extract the basic parameter system of the carbon emission accounting model, including carbon emission parameters, carbon sequestration parameters, process parameters and correlation coefficient parameters; S6-2: Based on the preset segmented carbon emission-carbon sequestration coupling calculation algorithm, the independent carbon emission of each segment is first calculated according to the basic parameter system, and then the total carbon sequestration is decomposed to each segment according to the carbon sequestration contribution coefficient. Segment-level carbon emission-carbon sequestration coupling offset is performed to obtain the coupled net carbon emission of each segment and the total net carbon emission of the system. S6-3: Based on the process parameters, establish the carbon emission coefficient and carbon sequestration factor to obtain the process parameter correction coefficient. Then, use the process parameter correction coefficient to calculate the corrected carbon emissions of each stage and the total carbon sequestration of the system under different process parameters. Substitute these into the calculation formulas for the coupled net carbon emissions of each stage and the total net carbon emissions of the system to obtain the total net carbon emissions of the system under different combinations of process parameters.

3. The method for synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gas co-production according to claim 2, characterized in that: In S6-1, the carbon emission parameters are obtained based on the results of each step in S1-S5, specifically as follows: The carbon emission parameters for step S1 include the weight of flue-cured tobacco straw processed. Diesel consumption per unit of straw collection, storage and transportation Carbon emissions from diesel combustion ; The carbon emission parameters for step S2 include the total power consumption of the pretreatment process. Carbon emission factors of power grid ; The carbon emission parameters for step S3 include the total electricity consumption of the pyrolysis gasification process. Carbon emissions from incomplete combustion of flue-cured tobacco straw ; The carbon emission parameters for step S4 include total combustible gas emissions. ; The carbon emission parameters for step S5 include the carbon emission factor from combusted gas. ; Carbon emission parameters also include those from each stage. or Conversion Equivalent coefficient ; In S6-1, the carbon fixation parameters include the total yield of crude biochar. Biochar fixed carbon content Annual mineralization loss rate of biochar Carbon and Conversion coefficient Actual amount of biochar returned to the field ; In step S6-1, the process parameters include the particle size of the straw material in steps S1 and S2. The pyrolysis temperature of the S3 pyrolysis gasification process heating rate oxygen volume fraction ; In S6-1, the correlation coefficient parameter includes the carbon sequestration contribution coefficient of the collection, storage and transportation process. carbon sequestration contribution coefficient of pretreatment stage Carbon sequestration contribution coefficient in pyrolysis gasification process Carbon sequestration contribution coefficient in combustible gas utilization The above correlation coefficient parameters were obtained through iterative optimization based on an improved genetic algorithm.

4. The method for synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gas co-production according to claim 3, characterized in that: In S6-2, based on a preset segmented carbon emission-carbon sequestration coupling calculation algorithm, the independent carbon emissions of each segment are first calculated according to the basic parameter system. Then, the total carbon sequestration is decomposed into each segment according to the carbon sequestration contribution coefficient, and segment-level carbon emission-carbon sequestration coupling offset is performed to obtain the specific net carbon emissions of each segment and the total net carbon emissions of the system: Based on the actual carbon sequestration amount of biochar returned to the field, and after deducting mineralization losses, the total carbon sequestration amount of the system is calculated using the following expression: in, This represents the total carbon sequestration of the system. This represents the total yield of crude biochar. To fix the carbon content in biochar; The annual mineralization loss rate of biochar; For carbon and Conversion coefficient; Carbon emissions from the four stages of collection, storage, transportation, pretreatment, pyrolysis and gasification, and combustible gas utilization should be calculated separately. , , , The expression is: in, This indicates carbon emissions during the collection, storage, and transportation process; Indicates the processed weight of flue-cured tobacco straw; This indicates the amount of diesel fuel consumed per unit of straw collection, storage, and transportation. Indicates the carbon emission factor of diesel combustion; express or Conversion Equivalent coefficient ; in, This indicates carbon emissions during the pretreatment process; This indicates the total power consumption of the pretreatment stage; Indicates the local power grid carbon emission factor; in, This indicates carbon emissions during the pyrolysis and gasification process; This indicates the carbon emission factor from the incomplete combustion of flue-cured tobacco straw; This indicates the total power consumption during the pyrolysis and gasification process; in, This indicates carbon emissions during the utilization of combustible gas; Indicates the carbon emission factor of combustible gas combustion; Total carbon sequestration in the system Based on the carbon sequestration contribution coefficient of each link in the correlation coefficient parameters , , , The carbon sequestration amount is obtained by breaking it down into each carbon emission stage. , , , Then calculate the net carbon emissions of each coupled process. , , , The expression is: ； ； ； ； in, Carbon sequestration during the collection, storage, and transportation process; This refers to the amount of carbon fixed during the pretreatment process. This refers to the amount of carbon fixed during the pyrolysis gas process. The amount of carbon sequestration during the utilization of combustible gas; ； ； ； ； in, Couple net carbon emissions to the collection, storage, and transportation processes; To couple net carbon emissions to the pretreatment process; This is to couple net carbon emissions to the pyrolysis gas process; Coupled with net carbon emissions in the combustible gas utilization process; The total net carbon emissions of the system are calculated based on the coupling of each stage, and the expression is as follows: in, This represents the system's total net carbon emissions.

5. The method for synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gasification and charcoal production according to claim 4, characterized in that: In step S6-3, based on the process parameters, the carbon emission coefficient and carbon sequestration factor are quantified to obtain the process parameter correction coefficient. The corrected carbon emissions of each stage and the total carbon sequestration of the system under different process parameters are then calculated using this correction coefficient. Substituting these factors into the formulas for calculating the coupled net carbon emissions of each stage and the total net carbon emissions of the system, the specific total net carbon emissions of the system under different combinations of process parameters are obtained as follows: Process parameters: straw material particle size pyrolysis temperature heating rate oxygen volume fraction As dynamic input variables, a quantitative correlation is established between process parameters and carbon emission coefficients and carbon sequestration factors to obtain process parameter correction coefficients. The expression is: in, This represents the correlation coefficient between pyrolysis temperature and carbon emission and fixation. This represents the reference value for pyrolysis temperature; This represents the correlation coefficient between the heating rate and carbon emissions and carbon sequestration. This represents the baseline value for the heating rate; This represents the correlation coefficient between oxygen volume fraction and carbon emissions and carbon sequestration. This indicates the baseline value for oxygen volume fraction; This represents the correlation coefficient between material particle size and carbon emission and carbon sequestration. Indicates the reference value for material particle size; Correction coefficient for process parameters By introducing the calculation formulas for carbon emissions at each stage and total carbon sequestration in the system, the corrected carbon emissions and total carbon sequestration under different combinations of process parameters are obtained. The expressions for the corrected carbon emissions at each stage are as follows: ； ； ； ； The revised expression for total solid carbon content in the system is: in, , , , These represent the corrected carbon emissions from the collection, storage, and transportation process, the corrected carbon emissions from the pretreatment process, the corrected carbon emissions from the pyrolysis and gasification process, and the corrected carbon emissions from the combustible gas utilization process, respectively. This indicates the total carbon sequestration in the system after correction. Based on the corrected carbon emissions of each stage and the corrected total carbon sequestration of the system, substituting these values ​​into the calculation formulas for the coupled net carbon emissions of each stage and the total net carbon emissions of the system, the total net carbon emissions of the system under different combinations of process parameters are obtained, as expressed in the following expression: in, This represents the corrected total net carbon emissions of the system.

6. The method for synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gas co-production according to claim 5, characterized in that: The parameters of each correlation coefficient are obtained through iterative optimization using an improved genetic algorithm, as follows: Based on the carbon sequestration contribution coefficients of each link in the correlation coefficient parameters and their constraints, an objective function for minimizing the accounting error and an objective function for maximizing the system's net emission reduction are constructed. The expression for the objective function for minimizing the accounting error is as follows: in, This represents the calculated net emission reduction value of the system. , This represents the measured net emission reduction of the system. The objective function expression for maximizing the system's net emission reduction is: Normalize the two objective functions to obtain the processed objective function. , Then, the adaptive weights of each objective function are dynamically calculated based on the number of iterations. , The expression is: in, To calculate the weights of the objective function that minimizes the accounting error, The weights of the objective function for maximizing the system's net emission reduction are given; then the fitness function expression is: in, The fitness function; Determine whether the current iteration meets the convergence termination condition. If yes, output the optimal solution. If no, extract the global elite individuals and local elite individuals from the current population. The global elite individuals are directly copied to the next iteration, and the local elite individuals are stored in the elite pool. The tournament selection method is used to randomly select k individuals from the population, and the individual with the smallest fitness value is selected to enter the crossover stage; Simulated binary crossover is employed, based on a preset adaptive crossover probability operator. New individuals are generated by randomly selecting one individual from the elite pool for crossover, using a preset adaptive crossover probability operator. The expression is: in, , represent the upper and lower bounds of the crossover probability, respectively. The smaller fitness value among the two individuals to be crossed. This represents the average fitness value of the current population. This represents the minimum fitness value of the current population. Polynomial mutation is employed, based on a pre-defined adaptive mutation probability operator. For new individual gene perturbations, genes exceeding the range are corrected according to corresponding constraints, using a pre-defined adaptive mutation probability operator. The expression is: in, , These represent the upper and lower limits of the mutation probability. The fitness value of the individual to be mutated; The new individuals generated through crossover and mutation are combined with the global elite individuals to form a new generation of population, and fitness values ​​are calculated. After iterative convergence, the result with the minimum fitness value in the population is output, and the optimal carbon fixation contribution coefficient set is obtained after decoding. ; The decoded optimal carbon sequestration contribution coefficient set is substituted into the carbon emission accounting model for verification. After verification, it is directly input into the carbon emission accounting model for accounting. Real-time monitoring of process parameter correction coefficients The range of change, if If the change exceeds the preset change threshold, the improved genetic algorithm will be directly triggered to iterate again to obtain the optimal set of carbon fixation contribution coefficients adapted to the new process parameters.

7. The method for synergistic carbon sequestration and carbon emission accounting of flue-cured tobacco straw gas co-production according to claim 1, characterized in that: S5 includes: S5-1: The combustible gas obtained in step S4 is transported to the combustible gas utilization unit through a sealed insulated pipeline. It is then divided into two paths by a branch regulating valve, one path being transported to the gas power generation module and the other path being transported to the gas heating module. S5-2: The crude biochar obtained from step S4 is transported to the raw material buffer bin of the biochar utilization and carbon fixation unit. Metal impurities in the crude biochar are removed by magnetic separation equipment, and fine powder biochar with a particle size of less than 1 mm and coarse block biochar with a particle size of more than 20 mm are removed by screening equipment, leaving uniform crude biochar raw material with a particle size of 1-20 mm. S5-3: Based on the soil requirements of the flue-cured tobacco planting area, a modifier is used to perform targeted modification of the crude biochar; S5-4: Apply the modified biochar evenly to the surface of the flue-cured tobacco planting field and till the soil to fully mix the biochar with the topsoil. S5-5: Record the actual amount of biochar returned to the field and the carbon emission sources from combustible gas utilization.

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