A system and method for preparing carbon-fixing, non-fired ceramsite based on comprehensive utilization of sludge

Abstract

This invention discloses a carbon-fixing, non-fired ceramsite preparation system and method based on comprehensive utilization of sludge. The preparation system includes an anaerobic digester, a first pressure swing adsorption (PSA) tower, a second PSA tower, a carbon dioxide storage tank, a methane storage tank, a methane generator set, a dryer, a ball mill, a mixer, a granulator, a carbonization chamber, and a control system. The preparation method is as follows: Step 1, pretreated sludge is fed into the anaerobic digester; Step 2, purified crude biogas is distributed along pipelines to the first and second PSA towers; Step 3, high-temperature waste heat is transferred to the dryer for drying the biogas residue; Step 4, the residue is pressurized and returned to the carbon dioxide storage tank for recycling via a third gas compressor. Beneficial effects: Effectively reduces carbon emissions while improving the performance of the non-fired ceramsite, enabling its widespread application in building aggregates, roadbed fillers, and other scenarios, achieving multiple goals of resource recycling, energy conservation, and environmental protection.

Description

Technical Field

[0001] This invention relates to a system and method for preparing carbon-fixed, non-fired ceramsite, and particularly to a system and method for preparing carbon-fixed, non-fired ceramsite based on the comprehensive utilization of sludge. Background Technology

[0002] Currently, with the acceleration of urbanization and the advancement of projects such as river dredging, a large amount of silt is generated. If not properly handled, the large-scale dumping of silt will occupy valuable land resources, especially restricting the construction and development of areas surrounding cities. Furthermore, the organic matter inside the silt will release methane and carbon dioxide through microbial decomposition, increasing carbon emissions. Therefore, silt treatment is receiving increasing attention.

[0003] Non-fired ceramsite typically uses solid waste materials such as sludge, which is cured and shaped by adding cementitious materials and activators at room temperature or low temperature. It boasts advantages such as low investment and low cost, and is energy-saving and environmentally friendly, aligning with the concept of green development. Currently, the co-production of non-fired ceramsite using sludge with solid wastes such as fly ash, steel slag, and mine slag has become an important approach to the resource utilization of sludge. This type of non-fired ceramsite contains active components required for carbonization reactions, which can react with carbon dioxide to generate stable products such as calcium carbonate. This not only improves the performance and durability of the ceramsite but also enables carbon dioxide sequestration.

[0004] Existing technologies in the preparation of non-fired ceramsite from sludge, while focusing on the efficient utilization of sludge raw materials and the improvement of ceramsite performance, have neglected the optimization of energy consumption during the preparation process. This results in high overall energy consumption, falling short of the requirements for low-carbon production. In the carbonization stage, current carbonization devices mostly use carbon dioxide cylinders as the gas source, but no system for recovering and recycling the remaining carbon dioxide after carbonization has been designed. The direct emission of unreacted carbon dioxide not only wastes gas resources but also increases carbon emissions, violating the core goal of "carbon sequestration and reduction." More importantly, existing technologies have not established a synergistic technology system for the full utilization of sludge components, the preparation of non-fired ceramsite, and carbon sequestration. Sludge treatment is only used as a raw material supply link and is not linked with the energy consumption optimization of the non-fired preparation process and the carbon recycling of the carbonization process. Ultimately, the energy-saving and emission-reduction effects of the entire process are lower than expected, failing to achieve a balance between environmental, economic, and carbon sequestration benefits.

[0005] Therefore, designing a carbon-fixing, non-fired ceramsite preparation system and method based on the comprehensive utilization of sludge has become a pressing technical challenge in the field of building materials. This invention is proposed against this backdrop, aiming to achieve deep resource utilization of sludge through innovative design, reduce energy consumption in the ceramsite preparation process, form a closed-loop carbon dioxide recycling system, and achieve dual reduction of process carbon emissions, significantly improving the carbon fixation and reduction effect. Summary of the Invention

[0006] The main purpose of this invention is to solve the problem that existing sludge disposal methods are too simplistic, with organic components only undergoing simple fermentation to produce gas and inorganic components not being efficiently utilized, resulting in low comprehensive utilization of sludge and easy secondary pollution.

[0007] Another objective of this invention is to address the problems of high energy consumption, large carbon emissions, and high costs associated with existing non-fired ceramsite preparation methods that rely on fossil fuels for energy supply, require the purchase of industrial CO2 for carbonization and fixation, and do not recycle the carbon dioxide after carbonization.

[0008] Another objective of this invention is to address the existing problems of disconnect between sludge resource utilization and ceramsite preparation processes, the lack of an integrated preparation system, and the difficulty in achieving synergistic resource recycling and energy consumption optimization.

[0009] In order to achieve the above objectives and solve the above problems, the present invention provides a carbon-fixing non-fired ceramsite preparation system and method based on the comprehensive utilization of sludge.

[0010] The carbon-fixing, non-fired ceramsite preparation system based on comprehensive utilization of sludge provided by this invention includes an anaerobic fermenter, a first pressure swing adsorption (PSA) tower, a second PSA tower, a carbon dioxide storage tank, a methane storage tank, a methane generator set, a dryer, a ball mill, a mixer, a granulator, a carbonization chamber, and a control system. The input end of the parallel connection of the first and second PSA towers is connected to the anaerobic fermenter via a gas supply pipe. The output end of the parallel connection of the first and second PSA towers is connected to the carbon dioxide storage tank and the methane storage tank respectively via gas supply pipes. The methane generator set is connected to the methane storage tank, which provides methane for power generation. The methane generator set is connected to the dryer, ball mill, mixer, granulator, and carbonization chamber via power transmission lines. The methane generator set serves as the power source for the dryer, ball mill, and methane storage tank. The mixer, granulator, and carbonization chamber are powered by electricity. The anaerobic digester is connected to the dryer via a feed pipe. The material processed in the anaerobic digester is transported to the dryer via the feed pipe. The dryer is connected to the ball mill, mixer, granulator, and carbonization chamber in sequence via pipelines. The methane generator set is also connected to the control system via power lines. The methane generator set provides power to the control system. The control system is connected to the anaerobic digester, the first pressure swing adsorption tower, the second pressure swing adsorption tower, the carbon dioxide storage tank, the methane storage tank, the methane generator set, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber. The control system controls the operation of the anaerobic digester, the first pressure swing adsorption tower, the second pressure swing adsorption tower, the carbon dioxide storage tank, the methane storage tank, the methane generator set, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber.

[0011] The anaerobic digester is equipped with temperature and humidity sensors and pressure sensors. The connecting pipeline between the anaerobic digester and the first and second pressure swing adsorption towers is sequentially equipped with a first control valve, a biogas water seal tank, and a biogas purifier. The parallel pipeline connecting the biogas purifier to the first and second pressure swing adsorption towers is equipped with a second control valve and a third control valve, respectively. The temperature and humidity sensors, pressure sensors, first control valve, second control valve, and third control valve in the anaerobic digester are all connected to the control system. The temperature and humidity sensors and pressure sensors can transmit the collected data to the control system in real time. The control system controls the operation of the first control valve, second control valve, and third control valve based on the data transmitted by the temperature and humidity sensors and pressure sensors.

[0012] The bottom of the first pressure swing adsorption tower is connected to the top of the second pressure swing adsorption tower by a branch pipe. A bypass pipe is also connected between the first and second pressure swing adsorption towers. The bypass pipe is equipped with a fourth control valve and a fifth control valve. Both the fourth and fifth control valves are connected to the control system. The fourth and fifth control valves can transmit the collected data to the control system in real time. The control system controls the first and second pressure swing adsorption towers to work alternately according to the data transmitted by the fourth and fifth control valves. When one tower is in the adsorption and pressurization state, the other tower is in the desorption and regeneration state, thereby realizing the continuous separation and purification of biogas.

[0013] The carbon dioxide output ends at the bottom of the first and second pressure swing adsorption (PSA) towers are connected to parallel pipelines, on which a sixth and seventh control valve are installed. A first gas compressor and a first gas flow meter are sequentially installed on the connecting pipeline between the parallel pipeline and the carbon dioxide storage tank. A bypass pipe is connected to the methane output ends of the first and second PSA towers, and this bypass pipe is connected to the methane storage tank. A fourth and fifth control valve are installed on the bypass pipe. A second gas compressor and a second gas flow meter are sequentially installed on the connecting pipeline between the bypass pipe and the methane storage tank. An eighth control valve and a pressure reducing valve are sequentially installed on the connecting pipeline between the methane storage tank and the methane generator set. The fourth, fifth, sixth, and seventh control valves, the first gas compressor, the first gas flow meter, the second gas compressor, the eighth control valve, and the pressure reducing valve are all connected to and controlled by the control system.

[0014] The transmission lines connected to the methane generator set are also connected to the external power grid. These transmission lines are equipped with intelligent power distribution switchgear, which serves as the core power distribution hub. The intelligent power distribution switchgear has three access channels at its power input end: the first channel connects to the power output end of the methane generator set via cable; the second channel connects to the low-voltage side of the external power grid's distribution transformer via a dedicated power grid access cable; and the third channel is reserved for emergency backup power. The intelligent power distribution switchgear has a built-in power monitoring module that collects real-time data on the external power grid's voltage, current, frequency, and the methane generator set's output power, transmitting the signals to the control system. The intelligent power distribution switchgear also has a built-in dual-power automatic transfer switch, which is linked to both the methane generator set's power supply circuit and the external power grid's power supply circuit, and is also connected to the control system signal, enabling automatic switching between self-powered and external power grid-powered systems. The intelligent power distribution switchgear's power output end connects to all electrical equipment in the sludge fermentation system, the ceramsite preparation system, and the control system via branch cables, achieving unified power distribution.

[0015] The anaerobic digester, methane generator set, and dryer are all connected to the waste heat recovery device via pipelines. The waste heat generated during the power generation process of the methane generator set can be collected in real time by the waste heat recovery device and then transferred to the anaerobic digester and dryer for use.

[0016] A screw conveyor is installed on the conveying pipe connecting the anaerobic fermenter and the dryer. The screw conveyor is connected to the control system and is controlled by the control system.

[0017] The carbonization chamber and the carbon dioxide storage tank are connected via a circulation pipeline. A ninth control valve is installed on the inlet pipe between the carbon dioxide storage tank and the carbonization chamber. A tenth control valve, a gas-liquid separator, and a third gas compressor are sequentially installed on the outlet pipe between the carbonization chamber and the carbon dioxide storage tank. A vacuum pump is also connected to the carbonization chamber. The interior of the carbonization chamber is equipped with several layers of detachable support frames and temperature and humidity control elements. A carbon dioxide sensor and a temperature and humidity sensor are also installed inside the carbonization chamber. A carbon dioxide inlet is located within the carbonization chamber, which is connected to the outlet of the carbon dioxide storage tank via a gas delivery pipeline and the ninth control valve. A vacuum extraction port is also located within the carbonization chamber, which is connected to the inlet of the vacuum pump. The carbonization chamber is connected to the inlet of the carbon dioxide storage tank via the tenth control valve, gas-liquid separator, and third gas compressor on the gas pipeline. The carbon dioxide sensor, temperature and humidity sensor, ninth control valve, tenth control valve, gas-liquid separator, third gas compressor, and vacuum pump installed inside the carbonization chamber are all connected to the control system. The carbon dioxide sensor and temperature and humidity sensor installed inside the carbonization chamber can transmit the collected data to the control system in real time. The control system controls the operation of the ninth control valve, tenth control valve, gas-liquid separator, third gas compressor, and vacuum pump based on the data transmitted from the carbon dioxide sensor and temperature and humidity sensor.

[0018] The control system includes a data acquisition terminal, an analog-to-digital converter (ADC), a programmable logic controller (PLC), an industrial display screen, a data storage platform, a digital-to-analog converter (DAC), and actuators. The data acquisition terminal is connected to the ADC, which in turn is connected to the PLC. The PLC is connected to both the DAC and the data storage platform. The DAC is also connected to the industrial display screen and the actuators. The data acquisition terminal transmits real-time production process parameter data collected from the anaerobic digester, the first pressure swing adsorption (PSA) tower, the second PSA tower, the carbon dioxide storage tank, the methane storage tank, the methane generator set, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber to the ADC. The ADC converts the acquired analog signals into digital signals and transmits them to the PLC. The PLC analyzes and processes the digital signals, and the resulting real-time system operating status, data change curves, and anomaly warning information are visualized on the industrial display screen. Simultaneously, this processed data is stored on the data storage platform for subsequent process data traceability and model optimization training. The PLC then edits the processed control logic into digital control signals and transmits them to the DAC. The digital control signal is converted into an analog drive signal by a digital-to-analog converter (DAC). The analog drive signal is transmitted to the actuator through the DAC, and then the actuator starts the components in the anaerobic digester, the first pressure swing adsorption tower, the second pressure swing adsorption tower, the carbon dioxide storage tank, the methane storage tank, the methane generator set, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber according to the preset process logic, so as to realize the automated and precise control of the production process. The control flow of the programmable logic controller is as follows: during the system power initialization stage, the automatic switching switch is prioritized to connect to the external power grid, and the external power grid is used to power the anaerobic digester. The system supplies power to the fermentation tank, the first pressure swing adsorption tower, the second pressure swing adsorption tower, the carbon dioxide storage tank, the methane storage tank, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber, completing system startup and status self-checks. During operation, it analyzes the methane storage capacity, power generation, and process load requirements in real time, intelligently decides the optimal power supply mode, and regulates the power supply of the methane generator set and the external power grid by controlling the automatic switching switch to achieve grid-connected and off-grid operation. In self-powered mode or when the power supply capacity is limited, it automatically switches non-critical loads through actuators according to the preset power supply priority to ensure the safe and stable operation of the system.

[0019] The present invention provides a method for preparing carbon-fixing, non-fired ceramsite based on comprehensive utilization of sludge, the method comprising the following steps:

[0020] Step 1: The pretreated sludge is put into the anaerobic digester. The control system monitors the fermentation environment in real time through temperature and humidity sensors and pressure sensors inside the digester. When the parameters deviate from the set range, the system automatically adjusts the heat delivered to the digester by the waste heat recovery device to maintain a constant temperature anaerobic state. The organic matter in the sludge decomposes under the action of microorganisms, continuously producing biogas. The biogas accumulates in the anaerobic digester and generates pressure. It is discharged from the pipe at the top of the anaerobic digester, passes through the first control valve, and enters the biogas water seal tank and biogas purifier in sequence to remove hydrogen sulfide, moisture and impurities that are harmful to subsequent equipment, and obtain clean crude biogas.

[0021] Step 2: The purified crude biogas is distributed to the first and second pressure swing adsorption (PSA) towers via pipelines through the second and third control valves. The control system precisely controls the pressure switching cycle of the first and second PSA towers and the opening and closing sequence of the second, third, fourth, fifth, sixth, and seventh control valves, allowing the first and second PSA towers to alternately perform adsorption and desorption operations for continuous production. During the adsorption stage, the adsorbent selectively adsorbs carbon dioxide, and the enriched high-purity methane gas is discharged from the top of the tower. After being pressurized by the second gas compressor via the fourth and fifth control valves, it is then discharged through the second gas compressor. The gas is metered and transported to the methane storage tank by a flow meter. During the desorption stage, the enriched high-purity carbon dioxide gas is discharged from the bottom of the tower and pressurized by the first gas compressor after passing through the sixth and seventh control valves. It is then metered and transported to the carbon dioxide storage tank by the first gas flow meter. The control system monitors the gas production efficiency and the storage capacity of the carbon dioxide and methane storage tanks in real time based on the data from the first and second gas flow meters, and intelligently allocates the airflow path. At the same time, the control system starts the screw conveyor according to the fermentation cycle or the material level signal in the anaerobic digester to stably and continuously transport the biogas residue deposited at the bottom of the anaerobic digester to the dryer, completing the material transfer.

[0022] Step 3: When system equipment starts up or power demand increases, the control system receives the power load signal from the intelligent power distribution switchgear, as well as the voltage, frequency, and phase status of the external power grid. During system initialization, if the methane generator set is not started or its self-generated power is insufficient to support the total load, the control system prioritizes controlling the automatic power transfer switch in the intelligent power distribution switchgear to switch to the external power grid supply mode. The external power grid then supplies power to all subsystems in the system, ensuring safe startup and stable operation. When the control system detects sufficient methane storage in the methane tank and determines that the conditions for starting power generation are met, it controls the methane generator set to start. After its output voltage and frequency synchronize with the external power grid, the control system automatically switches to the grid-connected power supply mode, allowing the methane generator set and the external power grid to share the load, or optimizes the power generation mode according to a preset scheduling strategy. When the system needs to operate off-grid or conditions permit, the control system automatically switches to self-powered mode: controlling the automatic transfer switch to disconnect from the external power grid, and simultaneously opening the eighth control valve at the methane storage tank outlet. A pressure reducing valve regulates fuel supply. Methane gas is transported via pipeline to the methane generator set for combustion and power generation. The electricity generated by the methane generator set is uniformly distributed and dispatched by the intelligent power distribution switch cabinet to power the equipment that needs power within the system. Throughout the operation, the control system monitors the total load, power generation, and grid status of the intelligent power distribution switch cabinet in real time, dynamically adjusting the output power of the methane generator set and the opening of the gas valve to achieve "on-demand power generation" and intelligent load management, preventing overload. If an unexpected power outage is detected in the external power grid, the control system can complete a seamless switch to self-powered mode within milliseconds to ensure the continuity of the production process. When the external power grid is restored, the control system automatically performs synchronization and switches back to grid-connected power supply mode. The waste heat generated during the power generation process of the methane generator set is recovered by the waste heat recovery device. The control system intelligently allocates the waste heat flow according to the real-time heat demand of the anaerobic digester and the drying process requirements of the dryer: medium and low temperature waste heat is given priority to maintain the fermentation temperature of the anaerobic digester, and high temperature waste heat is transported to the dryer to dry the biogas residue, realizing the cascade utilization of thermal energy.

[0023] Step 4: After the wet biogas residue fed into the dryer is dried using waste heat, it is successively ground in a ball mill, mixed in a mixer, and shaped into raw non-fired ceramsite blanks by a granulator. The raw non-fired ceramsite blanks are then sent into the carbonization chamber, where they are layered and aged for a set time. The control system then starts the vacuum pump to evacuate the carbonization chamber to the vacuum level set for the carbonization process. Subsequently, according to the preset carbonization process requirements, the control system automatically opens the ninth control valve to introduce carbon dioxide from the carbon dioxide storage tank into the carbonization chamber through a pipeline, and activates the temperature and humidity control elements in the carbonization chamber to coordinate the control of the temperature, humidity, and carbon dioxide concentration within the carbonization chamber, stabilizing them within the set reaction range. Under the set conditions, the carbon dioxide reacts with the active components in the raw material blanks to generate high-strength, high-stability non-fired ceramsite products. After the carbonization reaction is completed, the control system opens the tenth control valve to purify the remaining carbon dioxide gas in the carbonization chamber through a gas-liquid separator, and then pressurizes it through the third gas compressor and returns it to the carbon dioxide storage tank for recycling, achieving efficient carbon sequestration and near-zero emissions.

[0024] The aforementioned anaerobic digester, first pressure swing adsorption tower, second pressure swing adsorption tower, carbon dioxide storage tank, methane storage tank, methane generator set, dryer, ball mill, mixer, granulator, carbonization chamber, first control valve, biogas water seal tank, biogas purifier, second control valve, third control valve, bypass pipe, fourth control valve, fifth control valve, sixth control valve, seventh control valve, first gas compressor, first gas flow meter, second gas compressor, second gas flow meter, eighth control valve, pressure reducing valve, intelligent power distribution switch cabinet, waste heat recovery device, screw conveyor, ninth control valve, tenth control valve, gas-liquid separator, third gas compressor, vacuum pump, data acquisition terminal, analog-to-digital converter, programmable logic controller, industrial display screen, data storage platform, digital-to-analog converter, and actuator are all assemblies of existing equipment; therefore, specific models and specifications are not detailed.

[0025] The beneficial effects of this invention are:

[0026] The carbon-fixing, non-fired ceramsite preparation system and method based on comprehensive utilization of sludge provided by this invention utilizes different components of sludge for deep resource utilization. It not only converts the organic matter in the sludge into electricity and carbon resources through fermentation and gas production, but also uses the inorganic residue after fermentation as raw material for ceramsite preparation. This not only makes large-scale use of sludge, reducing the land occupation and environmental pollution caused by sludge stockpiling, but also uses fermentation gas methane power generation to replace fossil energy for the preparation of non-fired ceramsite, significantly reducing energy consumption. Furthermore, through the carbonization and carbon fixation process of non-fired ceramsite, carbon dioxide in the fermentation gas is recovered and utilized, achieving carbon sequestration of carbon dioxide and effectively reducing carbon emissions. At the same time, it improves the performance of non-fired ceramsite and can be widely used in building aggregates, roadbed fillers, and other scenarios, taking into account multiple goals of resource recycling, energy conservation, and environmental protection. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the carbon-fixing, non-fired ceramsite preparation system described in this invention.

[0028] Figure 2 This is a block diagram of the control system structure described in this invention.

[0029] The annotations in the diagram are as follows:

[0030] 1. Anaerobic fermenter; 2. First pressure swing adsorption tower; 3. Second pressure swing adsorption tower.

[0031] 4. Carbon dioxide storage tank; 5. Methane storage tank; 6. Methane generator set.

[0032] 7. Dryer; 8. Ball mill; 9. Mixer; 10. Granulator; 11. Carbonization chamber.

[0033] 12. Control system; 13. First control valve; 14. Biogas water seal tank; 15. Biogas purifier.

[0034] 16. Second control valve; 17. Third control valve; 18. Bypass pipe; 19. Fourth control valve.

[0035] 20. Fifth control valve; 21. Sixth control valve; 22. Seventh control valve; 23. First gas compressor.

[0036] 24. First gas flow meter; 25. Second gas compressor; 26. Second gas flow meter.

[0037] 27. Eighth control valve; 28. Pressure reducing valve; 29. ​​External power grid; 30. Intelligent power distribution switchgear.

[0038] 31. Waste heat recovery device; 32. Screw conveyor; 33. Ninth control valve; 34. Tenth control valve.

[0039] 35. Gas-liquid separator; 36. Third gas compressor; 37. Vacuum pump; 38. Data acquisition terminal.

[0040] 39. Analog-to-digital converter; 40. Programmable logic controller; 41. Industrial display screen.

[0041] 42. Data storage platform; 43. Digital-to-analog converter; 44. Actuator. Detailed Implementation

[0042] Please see Figures 1 to 2 As shown:

[0043] The carbon-fixing, non-fired ceramsite preparation system based on comprehensive utilization of sludge provided by this invention includes an anaerobic fermenter 1, a first pressure swing adsorption (PSA) tower 2, a second PSA tower 3, a carbon dioxide storage tank 4, a methane storage tank 5, a methane generator set 6, a dryer 7, a ball mill 8, a mixer 9, a granulator 10, a carbonization chamber 11, and a control system 12. The input end of the parallel connection of the first PSA tower 2 and the second PSA tower 3 is connected to the anaerobic fermenter 1 via a gas supply pipe. The output of the adsorption tower 2 and the second pressure swing adsorption tower 3, connected in parallel, is connected to the carbon dioxide storage tank 4 and the methane storage tank 5 respectively via gas pipelines. The methane generator set 6 is connected to the methane storage tank 5, which provides methane for power generation. The methane generator set 6 is connected to the dryer 7, ball mill 8, mixer 9, granulator 10, and carbonization chamber 11 via power transmission lines. The methane generator set 6 serves the dryer 7, ball mill 8, mixer 9, and granulator 10. The anaerobic digester 10 and carbonization chamber 11 are powered. The anaerobic digester 1 is connected to the dryer 7 via a feed pipe. The material processed by the anaerobic digester 1 is transported to the dryer 7 via the feed pipe. The dryer 7 is connected to the ball mill 8, mixer 9, granulator 10 and carbonization chamber 11 in sequence via pipelines. The methane generator set 6 is also connected to the control system 12 via a power transmission line. The methane generator set 6 provides power to the control system 12. The control system 12 is connected to the anaerobic digester 1, the ball mill 8, the mixer 9, the granulator 10 and carbonization chamber 11 respectively. The anaerobic digester 1, the first pressure swing adsorption tower 2, the second pressure swing adsorption tower 3, the carbon dioxide storage tank 4, the methane storage tank 5, the methane generator set 6, the dryer 7, the ball mill 8, the mixer 9, the granulator 10, and the carbonization chamber 11 are connected. The control system 12 controls the operation of the anaerobic digester 1, the first pressure swing adsorption tower 2, the second pressure swing adsorption tower 3, the carbon dioxide storage tank 4, the methane storage tank 5, the methane generator set 6, the dryer 7, the ball mill 8, the mixer 9, the granulator 10, and the carbonization chamber 11.

[0044] The anaerobic digester 1 is equipped with a temperature and humidity sensor and a pressure sensor. The connecting pipeline between the anaerobic digester 1 and the first pressure swing adsorption tower 2 and the second pressure swing adsorption tower 3 is sequentially equipped with a first control valve 13, a biogas water seal tank 14, and a biogas purifier 15. The parallel pipeline connecting the biogas purifier 15 and the first pressure swing adsorption tower 2 and the second pressure swing adsorption tower 3 is equipped with a second control valve 16 and a third control valve 17, respectively. The temperature and humidity sensor, the pressure sensor, the first control valve 13, the second control valve 16, and the third control valve 17 in the anaerobic digester 1 are all connected to the control system 12. The temperature and humidity sensor and the pressure sensor can transmit the collected data to the control system 12 in real time. The control system 12 controls the operation of the first control valve 13, the second control valve 16, and the third control valve 17 according to the transmitted data from the temperature and humidity sensor and the pressure sensor.

[0045] A branch pipe connects the bottom of the first pressure swing adsorption tower 2 to the top of the second pressure swing adsorption tower 3. A bypass pipe 18 also connects the first pressure swing adsorption tower 2 and the second pressure swing adsorption tower 3. A fourth control valve 19 and a fifth control valve 20 are installed on the bypass pipe 18. Both the fourth control valve 19 and the fifth control valve 20 are connected to the control system 12. The fourth control valve 19 and the fifth control valve 20 can transmit the collected data to the control system 12 in real time. The control system 12 controls the first pressure swing adsorption tower 2 and the second pressure swing adsorption tower 3 to work alternately according to the data transmitted by the fourth control valve 19 and the fifth control valve 20. When one tower is in the adsorption and pressurization state, the other tower is in the desorption and regeneration state, thereby realizing the continuous separation and purification of biogas.

[0046] The carbon dioxide output ends of the first pressure swing adsorption (PSA) tower 2 and the second PSA tower 3 are connected to parallel pipelines. A sixth control valve 21 and a seventh control valve 22 are installed on the parallel pipelines. A first gas compressor 23 and a first gas flow meter 24 are sequentially installed on the connecting pipeline between the parallel pipelines and the carbon dioxide storage tank 4. A bypass pipe 18 is connected to the methane output ends of the first and second PSA towers. The bypass pipe 18 is connected to the methane storage tank 5. A fourth control valve 19 and a fifth control valve 20 are installed on the bypass pipe 18. The second gas compressor 25 and the second gas flow meter 26 are sequentially installed on the connecting pipeline between the methane storage tank 5 and the methane generator set 6. The eighth control valve 27 and the pressure reducing valve 28 are sequentially installed on the connecting pipeline between the methane storage tank 5 and the methane generator set 6. The fourth control valve 19, the fifth control valve 20, the sixth control valve 21, the seventh control valve 22, the first gas compressor 23, the first gas flow meter 24, the second gas compressor 25, the eighth control valve 27 and the pressure reducing valve 28 are all connected to the control system 12 and are controlled by the control system 12.

[0047] The transmission line connected to the methane generator set 6 is also connected to the external power grid 29. The transmission line is also equipped with an intelligent power distribution switch cabinet 30, which serves as the core power distribution hub. The intelligent power distribution switch cabinet 30 has three access channels at its power input end: the first channel connects to the power output end of the methane generator set 6 via a cable; the second channel connects to the low-voltage side of the distribution transformer of the external power grid 29 via a dedicated power grid access cable; and the third channel has a reserved emergency backup power interface. The intelligent power distribution switch cabinet 30 has a built-in power monitoring module that collects real-time data on the external power grid voltage, current, frequency, and the output power of the methane generator set 6, and transmits the signals to the control system 12. The intelligent power distribution switch cabinet 30 also has a built-in dual-power automatic transfer switch, which is linked to both the power supply circuit of the methane generator set 6 and the power supply circuit of the external power grid 29, and is also connected to the control system 12 via a signal connection, enabling automatic switching between self-powered and external power grid 29 powered supply. The power output end of the intelligent power distribution switch cabinet 30 is connected via branch cables to all electrical equipment in the sludge fermentation system, the ceramsite preparation system, and the control system 12, achieving unified power distribution.

[0048] Anaerobic fermenter 1, methane generator set 6 and dryer 7 are all connected to waste heat recovery device 31 through pipelines. The waste heat generated by methane generator set 6 during power generation can be collected by waste heat recovery device 31 in real time and then transferred to anaerobic fermenter 1 and dryer 7 for use.

[0049] A screw conveyor 32 is installed on the conveying pipe connecting the anaerobic fermenter 1 and the dryer 7. The screw conveyor 32 is connected to the control system 12 and is controlled by the control system 12.

[0050] The carbonization chamber 11 is connected to the carbon dioxide storage tank 4 via a circulation pipeline. A ninth control valve 33 is installed on the inlet pipe between the carbon dioxide storage tank 4 and the carbonization chamber 11. A tenth control valve 34, a gas-liquid separator 35, and a third gas compressor 36 are sequentially installed on the outlet pipe between the carbonization chamber 11 and the carbon dioxide storage tank 4. A vacuum pump 37 is also connected to the carbonization chamber 11. The carbonization chamber 11 contains several layers of detachable support frames and temperature and humidity control elements. A carbon dioxide sensor and a temperature and humidity sensor are also installed inside the carbonization chamber 11. A carbon dioxide inlet is located inside the carbonization chamber 11, which is connected to the outlet of the carbon dioxide storage tank 4 via a gas delivery pipeline and the ninth control valve 33. A vacuum extraction port is also located inside the carbonization chamber 11, which is connected to the inlet of the vacuum pump 37. The carbonization chamber 11 is equipped with a carbon dioxide recovery port, which is connected to the inlet of the carbon dioxide storage tank 4 via the tenth control valve 34, gas-liquid separator 35, and third gas compressor 36 on the gas pipeline. The carbon dioxide sensor, temperature and humidity sensor, ninth control valve 33, tenth control valve 34, gas-liquid separator 35, third gas compressor 36, and vacuum pump 37 installed inside the carbonization chamber 11 are all connected to the control system 12. The carbon dioxide sensor and temperature and humidity sensor installed inside the carbonization chamber 11 can transmit the collected data to the control system 12 in real time. The control system 12 controls the operation of the ninth control valve 33, tenth control valve 34, gas-liquid separator 35, third gas compressor 36, and vacuum pump 37 based on the transmitted data from the carbon dioxide sensor and temperature and humidity sensor.

[0051] The control system 12 includes a data acquisition terminal 38, an analog-to-digital converter 39, a programmable logic controller 40, an industrial display screen 41, a data storage platform 42, a digital-to-analog converter 43, and actuators 44. The data acquisition terminal 38 is connected to the analog-to-digital converter 39, which is connected to the programmable logic controller 40. The programmable logic controller 40 is connected to both the digital-to-analog converter 43 and the data storage platform 42. The digital-to-analog converter 43 is also connected to the industrial display screen 41 and the actuators 44. The data acquisition terminal connects the anaerobic digester 1, the first pressure swing adsorption tower 2, the second pressure swing adsorption tower 3, the carbon dioxide storage tank 4, the methane storage tank 5, and the methane generator set. 6. Production process parameter data collected from the dryer, 7. ball mill, 8. mixer, 9. granulator, 10. and carbonization chamber 11 are transmitted in real time to the analog-to-digital converter 39. The analog-to-digital converter 39 converts the collected analog signals into digital signals and transmits them to the programmable logic controller 40. The real-time operating status, data change curves, and abnormal warning information of the system obtained by the programmable logic controller 40 after analyzing and processing the digital signals can be visualized on the industrial display screen 41. At the same time, the processed data is synchronously stored in the data storage platform 42 for subsequent process data traceability and optimization model training. The programmable logic controller 40 edits the processed control logic into digital control signals and... The signal is transmitted to the digital-to-analog converter 43, which converts the digital control signal into an analog drive signal. The analog drive signal is then transmitted to the actuator 44 via the digital-to-analog converter 43. The actuator 44 then starts the components in the anaerobic fermenter 1, the first pressure swing adsorption tower 2, the second pressure swing adsorption tower 3, the carbon dioxide storage tank 4, the methane storage tank 5, the methane generator set 6, the dryer 7, the ball mill 8, the mixer 9, the granulator 10, and the carbonization chamber 11 according to the preset process logic, thereby achieving automated and precise control of the production process. The control flow of the programmable logic controller 40 is as follows: During the system power initialization phase, the automatic switching switch is prioritized to connect to the external power grid 29, utilizing external power... Power grid 29 supplies power to anaerobic digester 1, first pressure swing adsorption tower 2, second pressure swing adsorption tower 3, carbon dioxide storage tank 4, methane storage tank 5, dryer 7, ball mill 8, mixer 9, granulator 10, and carbonization chamber 11, completing system startup and status self-check. During operation, it analyzes methane storage capacity, power generation, and process load requirements in real time, intelligently decides the optimal power supply mode, and controls the power supply of methane generator set 6 and external power grid 29 by controlling the automatic switching switch to achieve grid-connected and off-grid operation. In self-powered mode or when power capacity is limited, it automatically switches non-critical loads through actuator 44 according to the preset power supply priority to ensure safe and stable system operation.

[0052] The present invention provides a method for preparing carbon-fixing, non-fired ceramsite based on comprehensive utilization of sludge, the method comprising the following steps:

[0053] Step 1: The pretreated sludge is put into the anaerobic fermentation tank 1. The control system 12 monitors the fermentation environment in real time through the temperature and humidity sensor and the pressure sensor inside the tank. When the parameters deviate from the set range, the system automatically adjusts the heat delivered to the tank by the waste heat recovery device 31 to maintain a constant temperature anaerobic state. The organic matter in the sludge is decomposed under the action of microorganisms, continuously producing biogas. The biogas produced accumulates in the anaerobic fermentation tank 1 and generates pressure. It is discharged from the pipe at the top of the anaerobic fermentation tank 1, passes through the first control valve 13, and enters the biogas water seal tank 14 and biogas purifier 15 in sequence to remove hydrogen sulfide, moisture and impurities that are harmful to subsequent equipment, and obtain clean crude biogas.

[0054] Step 2: The purified crude biogas is distributed along the pipeline to the first pressure swing adsorption tower 2 and the second pressure swing adsorption tower 3 via the second control valve 16 and the third control valve 17. The control system 12 can precisely control the pressure switching cycle of the first pressure swing adsorption tower 2 and the second pressure swing adsorption tower 3 and the opening and closing sequence of the second control valve 16, the third control valve 17, the fourth control valve 19, the fifth control valve 20, the sixth control valve 21 and the seventh control valve 22, so that the first pressure swing adsorption tower 2 and the second pressure swing adsorption tower 3 alternately perform adsorption and desorption operations to achieve continuous production. In the adsorption stage, the adsorbent selectively adsorbs carbon dioxide, and the enriched high-purity methane gas is discharged from the top of the tower. After being pressurized by the second gas compressor 25 via the fourth control valve 19 and the fifth control valve 20, it is then discharged through the first control valve 16 and the third control valve 27. The gas flow meter 26 measures and delivers the gas to the methane storage tank 5. During the desorption stage, the enriched high-purity carbon dioxide gas is discharged from the bottom of the tower and pressurized by the first gas compressor 23 via the sixth control valve 21 and the seventh control valve 22, respectively. Then, it is measured and delivered to the carbon dioxide storage tank 4 via the first gas flow meter 24. The control system 12 monitors the gas production efficiency and the storage capacity of the carbon dioxide storage tank 4 and the methane storage tank 5 in real time based on the data from the first gas flow meter 24 and the second gas flow meter 26, and intelligently allocates the airflow path. At the same time, the control system 12 starts the screw conveyor 32 according to the fermentation cycle or the material level signal in the anaerobic digester 1 to stably and continuously transport the biogas residue deposited at the bottom of the anaerobic digester 1 to the dryer 7, thus completing the material transfer.

[0055] Step 3: When the system's electrical equipment starts up or the power demand increases, the control system 12 receives the power load signal fed back from the intelligent power distribution switch cabinet 30, as well as the voltage, frequency, and phase status of the external power grid 29. During the system initialization phase, if the methane generator set 6 is not started or its self-generated power is insufficient to support the total load, the control system 12 prioritizes controlling the automatic power transfer switch within the intelligent power distribution switch cabinet 30 to switch to the external power grid 29 power supply mode. The external power grid 29 then supplies power to all subsystems within the entire system, ensuring safe system startup and stable operation. When the control system 12... When the methane storage tank 5 is found to have sufficient gas storage and the conditions for starting power generation are determined, the methane generator set 6 is started. After its output voltage and frequency are synchronized with the external power grid 29, the control system 12 automatically switches to the grid-connected power supply mode, so that the methane generator set 6 and the external power grid 29 share the load, or optimizes the power generation mode according to the preset dispatch strategy. When it is necessary or conditions permit the system to operate off-grid, the control system 12 automatically switches to the self-powered mode: the automatic transfer switch is disconnected from the external power grid 29, and the eighth control valve 2 at the outlet of the methane storage tank 5 is opened. 7 and pressure reducing valve 28 regulate fuel supply. Methane gas is transported through pipelines to methane generator set 6 for combustion and power generation. The electrical energy generated by methane generator set 6 is uniformly distributed and dispatched by intelligent power distribution switch cabinet 30 to supply power to the equipment in the system. During the entire operation, control system 12 monitors the total load, power generation, and grid status of intelligent power distribution switch cabinet 30 in real time, dynamically adjusting the output power and gas valve opening of methane generator set 6 to achieve "on-demand power generation" and intelligent load management, preventing overload. If an unexpected power outage is detected in the external power grid 29, control system 12... It can complete the seamless switching to self-powered mode within milliseconds, ensuring the continuity of the production process; when the external power grid 29 is restored, the control system 12 automatically performs synchronization and switches back to grid-connected power supply mode; the waste heat generated during the power generation of the methane generator set 6 is recovered by the waste heat recovery device 31. The control system 12 intelligently allocates the waste heat flow according to the real-time heat demand of the anaerobic digester 1 and the drying process requirements of the dryer 7: the medium and low temperature waste heat is given priority to maintain the fermentation temperature of the anaerobic digester 1, and the high temperature waste heat is transported to the dryer 7 to dry the biogas residue, so as to realize the cascade utilization of thermal energy;

[0056] Step 4: After the wet biogas residue fed into dryer 7 is dried using waste heat, it is successively ground by ball mill 8, mixed by mixer 9, and shaped by granulator 10 to form non-fired ceramsite raw material blanks. The non-fired ceramsite raw material blanks are sent into carbonization chamber 11, and after being placed in layers for aging for a set time, control system 12 starts vacuum pump 37 to evacuate carbonization chamber 11 to the vacuum level set by the carbonization process. Subsequently, according to the preset carbonization process requirements, control system 12 automatically opens the ninth control valve 33 to input carbon dioxide from carbon dioxide storage tank 4 into carbonization chamber 11 through the pipeline, and starts carbonization chamber 11. The temperature and humidity control element in chamber 11 works together to control the temperature, humidity and carbon dioxide concentration in the carbonization chamber 11, keeping them stable within the set reaction range. Under the set conditions, carbon dioxide reacts with the active components in the raw material blank to produce high-strength and high-stability non-fired ceramsite products. After the carbonization reaction is completed, the control system 12 opens the tenth control valve 34, which purifies the remaining carbon dioxide gas in the carbonization chamber 11 through the gas-liquid separator 35, and then pressurizes it back to the carbon dioxide storage tank 4 through the third gas compressor 36 for recycling, achieving efficient carbon storage and near-zero emissions.

[0057] The aforementioned anaerobic digester 1, first pressure swing adsorption tower 2, second pressure swing adsorption tower 3, carbon dioxide storage tank 4, methane storage tank 5, methane generator set 6, dryer 7, ball mill 8, mixer 9, granulator 10, carbonization chamber 11, first control valve 13, biogas water seal tank 14, biogas purifier 15, second control valve 16, third control valve 17, bypass pipe 18, fourth control valve 19, fifth control valve 20, sixth control valve 21, seventh control valve 22, first gas compressor 23, first gas flow meter 24, second gas... Compressor 25, second gas flow meter 26, eighth control valve 27, pressure reducing valve 28, intelligent power distribution switch cabinet 30, waste heat recovery device 31, screw conveyor 32, ninth control valve 33, tenth control valve 34, gas-liquid separator 35, third gas compressor 36, vacuum pump 37, data acquisition terminal 38, analog-to-digital converter 39, programmable logic controller 40, industrial display screen 41, data storage platform 42, digital-to-analog converter 43, and actuator 44 are all assemblies of existing equipment; therefore, their specific models and specifications are not detailed.

Claims

1. A carbon-fixing, non-fired ceramsite preparation system based on comprehensive utilization of sludge, comprising an anaerobic fermenter, a first pressure swing adsorption (PSA) tower, a second PSA tower, a carbon dioxide storage tank, a methane storage tank, a methane generator set, a dryer, a ball mill, a mixer, a granulator, a carbonization chamber, and a control system. The input end of the parallel connection of the first and second PSA towers is connected to the anaerobic fermenter via a gas supply pipe. The output end of the parallel connection of the first and second PSA towers is connected to the carbon dioxide storage tank and the methane storage tank respectively via gas supply pipes. The methane generator set is connected to the methane storage tank, and the methane storage tank provides methane for power generation to the methane generator set. The methane generator set is connected to the dryer, ball mill, mixer, granulator, and carbonization chamber via power transmission lines. The methane generator set is an integral part of the dryer, ball mill, mixer, and carbonization chamber. The granulator and carbonization chamber are powered by electricity. The anaerobic digester is connected to the dryer via a conveying pipe. The material processed in the anaerobic digester is conveyed to the dryer via the conveying pipe. The dryer is connected to the ball mill, mixer, granulator, and carbonization chamber in sequence via pipelines. The methane generator set is also connected to the control system via power lines, providing power to the control system. The control system is connected to the anaerobic digester, the first pressure swing adsorption tower, the second pressure swing adsorption tower, the carbon dioxide storage tank, the methane storage tank, the methane generator set, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber. The control system controls the operation of the anaerobic digester, the first pressure swing adsorption tower, the second pressure swing adsorption tower, the carbon dioxide storage tank, the methane storage tank, the methane generator set, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber. Its characteristic is that: The anaerobic digester is equipped with temperature and humidity sensors and pressure sensors. A first control valve, a biogas water seal tank, and a biogas purifier are sequentially installed on the connecting pipes between the anaerobic digester and the first and second pressure swing adsorption (PSA) towers. A second control valve and a third control valve are respectively installed on the parallel pipes connecting the biogas purifier to the first and second PSA towers. The temperature and humidity sensors, pressure sensors, and the first, second, and third control valves in the anaerobic digester are all connected to the control system. The temperature and humidity sensors and pressure sensors can transmit the collected data to the control system in real time. The control system controls the operation of the first, second, and third control valves based on the transmitted data. A branch pipe connects the bottom of the first PSA tower to the top of the second PSA tower. A bypass pipe also connects the first and second PSA towers, and a fourth and fifth control valve are installed on the bypass pipe. The fourth and fifth control valves are also connected to the control system and can transmit the collected data to the control system in real time. The control system controls the operation of the fourth and fifth control valves based on the transmitted data. The data transmitted by the fifth control valve controls the alternating operation of the first and second pressure swing adsorption (PSA) towers. While one tower is in adsorption and pressurization mode, the other is in desorption and regeneration mode, thus achieving continuous separation and purification of biogas. The carbon dioxide output terminals at the bottom of the first and second PSA towers are connected to parallel pipelines, on which a sixth and seventh control valve are installed. A first gas compressor and a first gas flow meter are sequentially installed on the connecting pipeline between the parallel pipelines and the carbon dioxide storage tank. The methane output from the first and second PSA towers... A bypass pipe is connected to the outlet, which is connected to the methane storage tank. The bypass pipe is equipped with a fourth control valve and a fifth control valve. The connecting pipe between the bypass pipe and the methane storage tank is equipped with a second gas compressor and a second gas flow meter in sequence. The connecting pipe between the methane storage tank and the methane generator set is equipped with an eighth control valve and a pressure reducing valve in sequence. The fourth control valve, the fifth control valve, the sixth control valve, the seventh control valve, the first gas compressor, the first gas flow meter, the second gas compressor, the eighth control valve, and the pressure reducing valve are all connected to the control system and are controlled by the control system.

2. The carbon-fixing, non-fired ceramsite preparation system based on comprehensive utilization of sludge according to claim 1, characterized in that: The transmission line connected to the methane generator set is also connected to the external power grid. The transmission line is equipped with an intelligent power distribution switchgear, which serves as the core power distribution hub. The intelligent power distribution switchgear has three access channels at its power input end: the first channel connects to the power output end of the methane generator set via a cable; the second channel connects to the low-voltage side of the distribution transformer of the external power grid via a dedicated power grid access cable; and the third channel has a reserved emergency backup power interface. The intelligent power distribution switchgear has a built-in power monitoring module that collects real-time data on the external power grid voltage, current, frequency, and the output power of the methane generator set, and transmits the signals to the control system. The intelligent power distribution switchgear also has a built-in dual-power automatic transfer switch, which is linked to both the methane generator set power supply circuit and the external power grid power supply circuit, and is connected to the control system signal to achieve automatic switching between self-powered and external power grid powered systems. The power output end of the intelligent power distribution switchgear is connected via branch cables to all electrical equipment in the sludge fermentation system, the ceramsite preparation system, and the control system, achieving unified power distribution.

3. The carbon-fixing, non-fired ceramsite preparation system based on comprehensive utilization of sludge according to claim 1, characterized in that: The anaerobic digester, methane generator set, and dryer are all connected to the waste heat recovery device via pipelines. The waste heat generated during the power generation process of the methane generator set can be collected in real time by the waste heat recovery device and then transferred to the anaerobic digester and dryer for use.

4. The carbon-fixing, non-fired ceramsite preparation system based on comprehensive utilization of sludge according to claim 1, characterized in that: A screw conveyor is installed on the conveying pipe connecting the anaerobic fermenter and the dryer. The screw conveyor is connected to the control system and is controlled by the control system.

5. The carbon-fixing, non-fired ceramsite preparation system based on comprehensive utilization of sludge according to claim 1, characterized in that: The carbonization chamber and the carbon dioxide storage tank are connected via a circulation pipeline. A ninth control valve is installed on the inlet pipe between the carbon dioxide storage tank and the carbonization chamber. A tenth control valve, a gas-liquid separator, and a third gas compressor are sequentially installed on the outlet pipe between the carbonization chamber and the carbon dioxide storage tank. A vacuum pump is also connected to the carbonization chamber. The interior of the carbonization chamber is equipped with several layers of detachable support frames and temperature and humidity control elements. A carbon dioxide sensor and a temperature and humidity sensor are also installed inside the carbonization chamber. A carbon dioxide inlet is provided in the carbonization chamber, which is connected to the outlet of the carbon dioxide storage tank via a gas delivery pipeline and the ninth control valve. A vacuum extraction port is also provided in the carbonization chamber, which is connected to the inlet of the vacuum pump. The gas inlet is connected to the carbonization chamber; a carbon dioxide recovery port is set in the carbonization chamber, which is connected to the inlet of the carbon dioxide storage tank through the tenth control valve, gas-liquid separator and third gas compressor on the gas pipeline. The carbon dioxide sensor, temperature and humidity sensor, ninth control valve, tenth control valve, gas-liquid separator, third gas compressor and vacuum pump installed in the carbonization chamber are all connected to the control system. The carbon dioxide sensor and temperature and humidity sensor installed in the carbonization chamber can transmit the collected data to the control system in real time. The control system controls the operation of the ninth control valve, tenth control valve, gas-liquid separator, third gas compressor and vacuum pump according to the data transmitted by the carbon dioxide sensor and temperature and humidity sensor.

6. The carbon-fixing, non-fired ceramsite preparation system based on comprehensive utilization of sludge according to claim 1, characterized in that: The control system includes a data acquisition terminal, an analog-to-digital converter (ADC), a programmable logic controller (PLC), an industrial display screen, a data storage platform, a digital-to-analog converter (DAC), and actuators. The data acquisition terminal is connected to the ADC, which is connected to the PLC. The PLC is connected to both the DAC and the data storage platform. The DAC is also connected to the industrial display screen and the actuators. The data acquisition terminal transmits real-time production process parameter data collected from the anaerobic digester, the first pressure swing adsorption (PSA) tower, the second PSA tower, the carbon dioxide storage tank, the methane storage tank, the methane generator set, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber to the ADC. The ADC converts the collected analog signals into digital signals and transmits them to the PLC. The PLC analyzes and processes the digital signals, resulting in real-time system operating status, data change curves, and anomaly warning information, which are then visualized on the industrial display screen. Simultaneously, this processed data is stored on the data storage platform for subsequent process data traceability and model optimization training. The programmable logic controller (PLC) edits the processed control logic into digital control signals and transmits them to a digital-to-analog converter (DAC). The DAC converts the digital control signals into analog drive signals. These analog drive signals are then transmitted to the actuators via the DAC. The actuators, according to the preset process logic, start components in the anaerobic digester, first pressure swing adsorption (PSA) tower, second PSA tower, carbon dioxide storage tank, methane storage tank, methane generator set, dryer, ball mill, mixer, granulator, and carbonization chamber, achieving automated and precise control of the production process. The PLC's control flow is as follows: During the system power initialization phase, priority is given to controlling the automatic switching switch. The system connects to the external power grid to power the anaerobic digester, the first pressure swing adsorption tower, the second pressure swing adsorption tower, the carbon dioxide storage tank, the methane storage tank, the dryer, the ball mill, the mixer, the granulator, and the carbonization chamber. This completes the system startup and self-check. During operation, the system analyzes the methane storage capacity, power generation, and process load requirements in real time, intelligently decides the optimal power supply mode, and regulates the power supply of the methane generator set and the external power grid by controlling the automatic switching switch to achieve grid-connected and off-grid operation. In self-powered mode or when the power supply capacity is limited, the system automatically switches non-critical loads according to the preset power supply priority through actuators to ensure the safe and stable operation of the system.

7. A method for preparing carbon-fixing, non-fired ceramsite based on comprehensive utilization of sludge, characterized in that: The method includes the following steps: Step 1: The pretreated sludge is put into the anaerobic digester. The control system monitors the fermentation environment in real time through temperature and humidity sensors and pressure sensors inside the digester. When the parameters deviate from the set range, the system automatically adjusts the heat delivered to the digester by the waste heat recovery device to maintain a constant temperature anaerobic state. The organic matter in the sludge decomposes under the action of microorganisms, continuously producing biogas. The biogas accumulates in the anaerobic digester and generates pressure. It is discharged from the pipe at the top of the anaerobic digester, passes through the first control valve, and enters the biogas water seal tank and biogas purifier in sequence to remove hydrogen sulfide, moisture and impurities that are harmful to subsequent equipment, and obtain clean crude biogas. Step 2: The purified crude biogas is distributed to the first and second pressure swing adsorption (PSA) towers via pipelines through the second and third control valves. The control system precisely controls the pressure switching cycle of the first and second PSA towers and the opening and closing sequence of the second, third, fourth, fifth, sixth, and seventh control valves, allowing the first and second PSA towers to alternately perform adsorption and desorption operations for continuous production. During the adsorption stage, the adsorbent selectively adsorbs carbon dioxide, and the enriched high-purity methane gas is discharged from the top of the tower. After being pressurized by the second gas compressor via the fourth and fifth control valves, it is then discharged through the second gas compressor. The gas is metered and transported to the methane storage tank by a flow meter. During the desorption stage, the enriched high-purity carbon dioxide gas is discharged from the bottom of the tower and pressurized by the first gas compressor after passing through the sixth and seventh control valves. It is then metered and transported to the carbon dioxide storage tank by the first gas flow meter. The control system monitors the gas production efficiency and the storage capacity of the carbon dioxide and methane storage tanks in real time based on the data from the first and second gas flow meters, and intelligently allocates the airflow path. At the same time, the control system starts the screw conveyor according to the fermentation cycle or the material level signal in the anaerobic digester to stably and continuously transport the biogas residue deposited at the bottom of the anaerobic digester to the dryer, completing the material transfer. Step 3: When system equipment starts up or power demand increases, the control system receives the power load signal from the intelligent power distribution switchgear, as well as the voltage, frequency, and phase status of the external power grid. During system initialization, if the methane generator set is not started or its self-generated power is insufficient to support the total load, the control system prioritizes controlling the automatic power transfer switch in the intelligent power distribution switchgear to switch to the external power grid supply mode. The external power grid then supplies power to all subsystems in the system, ensuring safe startup and stable operation. When the control system detects sufficient methane storage in the methane tank and determines that the conditions for starting power generation are met, it controls the methane generator set to start. Once its output voltage and frequency are synchronized with the external power grid, the control system automatically switches to the grid-connected power supply mode, allowing the methane generator set and the external power grid to share the load. Alternatively, it optimizes the power generation mode according to a preset scheduling strategy. When necessary or conditions permit, the system can be disconnected from the grid. When the grid is running, the control system automatically switches to self-powered mode: the automatic switching switch disconnects from the external power grid, and simultaneously opens the eighth control valve and pressure reducing valve at the methane storage tank outlet to regulate fuel supply. Methane gas is transported through pipelines to the methane generator set for combustion and power generation. The electrical energy generated by the methane generator set is uniformly distributed and dispatched by the intelligent power distribution switch cabinet to power the equipment that needs power within the system. Throughout the operation, the control system monitors the total load, power generation, and grid status of the intelligent power distribution switch cabinet in real time, dynamically adjusting the output power and valve opening of the methane generator set to achieve "on-demand power generation" and intelligent load management, preventing overload. If an unexpected power outage is detected in the external power grid, the control system can complete the seamless switch to self-powered mode within milliseconds to ensure the continuity of the production process. When the external power grid is restored, the control system automatically performs synchronization and switches back to grid-connected power supply mode. The waste heat generated during the power generation process of the methane generator set is recovered by the waste heat recovery device. The control system intelligently allocates the waste heat flow according to the real-time heat demand of the anaerobic digester and the drying process requirements of the dryer: the medium and low temperature waste heat is given priority to maintain the fermentation temperature of the anaerobic digester, and the high temperature waste heat is transported to the dryer to dry the biogas residue, so as to realize the cascade utilization of thermal energy. Step 4: After the wet biogas residue fed into the dryer is dried using waste heat, it is successively ground in a ball mill, mixed in a mixer, and shaped into raw non-fired ceramsite blanks by a granulator. The raw non-fired ceramsite blanks are then sent into the carbonization chamber, where they are layered and aged for a set time. The control system then starts the vacuum pump to evacuate the carbonization chamber to the vacuum level set for the carbonization process. Subsequently, according to the preset carbonization process requirements, the control system automatically opens the ninth control valve to introduce carbon dioxide from the carbon dioxide storage tank into the carbonization chamber through a pipeline, and activates the temperature and humidity control elements in the carbonization chamber to coordinate the control of the temperature, humidity, and carbon dioxide concentration within the carbonization chamber, stabilizing them within the set reaction range. Under the set conditions, the carbon dioxide reacts with the active components in the raw material blanks to generate high-strength, high-stability non-fired ceramsite products. After the carbonization reaction is completed, the control system opens the tenth control valve to purify the remaining carbon dioxide gas in the carbonization chamber through a gas-liquid separator, and then pressurizes it through the third gas compressor and returns it to the carbon dioxide storage tank for recycling, achieving efficient carbon sequestration and near-zero emissions.

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