Sludge drying treatment system with precise control of oxygen content

Abstract

The present application relates to sludge drying treatment technical field, especially to a kind of sludge drying treatment system of precise control oxygen content;The system includes oxygen content monitoring module, safety state discrimination module, inert gas protection module, protective effect monitoring module and safety state analysis module.The present application is by setting multiple oxygen content probes, to monitor the oxygen concentration of different regions in real time, when there is risk, immediately start inert gas protection module control nitrogen injection valve opens, simultaneously, by executing continuous leak diagnosis, different coping strategies are executed, and by analyzing the matching degree of induced draft fan air volume and system state, automatically adjust operating parameters, so that the system is always maintained in optimal, most energy-saving safe state, when real-time oxygen content is low, analyze whether there is false appearance of temporary reduction of oxygen content reading due to combustible gas dilution, to improve the judgment ability of system to complex working conditions, nip in the bud, guarantee system safety and energy saving.

Description

Technical Field

[0001] This invention relates to the field of sludge drying technology, and more particularly to a sludge drying system for precise control of oxygen content. Background Technology

[0002] Powdered sludge is combustible dust. When dispersed in the air to form a dust-air mixture, it poses a dust explosion hazard upon contact with an ignition source. Dust generated after sludge drying is suspended in the air at an appropriate concentration, forming a dust cloud. If the dust concentration exceeds the lower explosive limit, there is a risk of dust explosion. A certain oxygen content is essential for dust combustion; when the oxygen concentration reaches a sufficient level, a dust explosion risk exists. In the sludge drying process, the stages most prone to dust explosion accidents are: the main dryer, the dust collection and treatment device, granulation, and the final treatment device. The causes of dust explosions are often the result of the cumulative effect of multiple factors.

[0003] Chinese Patent Publication No. CN103034184A discloses a safety control system for a sludge thermal drying silo. The system includes an online instrument group comprising: an online temperature sensor, an online pressure transmitter, an online oxygen content probe, an online carbon monoxide detection probe, a guided wave radar level gauge for measuring the material level in the silo, and an online level switch. The silo also includes a nitrogen pipeline and self-regulating valves. A PLC control unit and a host computer controller are also included. Control methods include: 1) micro-positive pressure inertial environment control; 2) smoldering warning control; 3) material level control; and 4) alarm operation. It is evident that existing drying system control technologies lack a mechanism that, based on real-time oxygen content monitoring, proactively diagnoses leaks and predicts combustible gas risks to identify false decreases in oxygen content caused by combustible gas accumulation. Furthermore, when false safety signals occur, the system should diagnose whether the root cause is excessively low rotation speed leading to sludge overheating or system seal failure, and implement targeted measures to address the problem at its source. This avoids the vulnerability of the safety barrier caused by a single oxygen content alarm, resulting in low intelligence in safety protection. Summary of the Invention

[0004] To address this, the present invention provides a sludge drying treatment system for precise control of oxygen content, thereby overcoming the problems in existing technologies that fail to identify false reductions in oxygen content caused by the accumulation of combustible gas through proactive leak diagnosis and combustible gas risk prediction, resulting in passive safety protection strategies and an inability to automatically eliminate hidden dangers at the source, leading to a low level of system intelligence.

[0005] To achieve the above objectives, the present invention provides a sludge drying treatment system for precise control of oxygen content, comprising:

[0006] An oxygen content monitoring module includes oxygen content probes installed at multiple monitoring points inside the drying equipment to obtain the real-time oxygen content at the monitoring points.

[0007] A safety status determination module, which is connected to the oxygen content monitoring module, is used to output a first prevention and control status signal or a second prevention and control status signal based on the comparison result between the real-time oxygen content and the first preset threshold.

[0008] An inert gas protection module, which is connected to the safety status determination module, is used to activate an emergency protection mode in response to the first prevention and control status signal, so as to inject inert gas into the drying equipment;

[0009] The protection effect monitoring module is connected to the oxygen content monitoring module and the inert gas protection module respectively. It is used to perform continuous leakage diagnosis after the inert gas protection module is activated, locate the leakage area based on the diagnosis results, and perform corresponding parameter optimization.

[0010] The safety status analysis module, which is connected to the safety status discrimination module, is used to respond to the second prevention and control status signal, perform explosion risk analysis based on real-time oxygen content and combustible gas concentration, and issue early warning prompts.

[0011] Furthermore, the security status determination module includes a first determination module and a second determination module;

[0012] The first discrimination module is used to issue a first prevention and control status signal when the real-time oxygen content monitored by any of the oxygen content probes is greater than a first preset threshold.

[0013] The second discrimination module is used to issue a second prevention and control status signal when the real-time oxygen content monitored by each of the oxygen content probes is less than or equal to the first preset threshold.

[0014] Furthermore, the protection effect monitoring module includes a leakage analysis unit and a parameter optimization unit;

[0015] The leakage analysis unit is used to determine whether there is a continuous leakage point based on the comparison result between the real-time oxygen content and the first preset threshold, and if there is a continuous leakage point, to determine the area where the continuous leakage point is located based on the real-time oxygen content and real-time response time of each oxygen content probe.

[0016] The parameter optimization unit is used to issue a location alarm signal based on the area type where the continuous leakage point is located, or to optimize the operating parameters of the induced draft fan based on the comparison between the operating air volume and the theoretical air extraction volume of the induced draft fan.

[0017] Furthermore, the leakage analysis unit includes a leakage determination subunit, a marking subunit, and a leakage point location subunit;

[0018] The leakage determination subunit is used to determine whether there is a first recovery moment and a second exceeding moment on the corresponding oxygen content recovery curve based on the comparison result between the real-time oxygen content of any monitoring point and the first preset threshold, so as to determine whether there is a continuous leakage point.

[0019] The marking subunit is used to mark the monitoring point as a target monitoring point when a persistent leak point exists;

[0020] The leak point location subunit determines the area where the continuous leak point is located based on the real-time oxygen content and real-time response time of the oxygen content probes at each of the target monitoring points.

[0021] Furthermore, the parameter optimization unit includes a matching analysis subunit and a parameter optimization subunit;

[0022] The matching analysis subunit is used to analyze the real-time matching degree between the induced draft fan and the theoretical air extraction volume required for the current evaporation of moisture and leakage gas, and obtain the analysis results;

[0023] The parameter optimization subunit is used to determine whether to adjust the induced draft fan speed based on the analysis results.

[0024] Furthermore, the safety status analysis module includes a combustible gas analysis unit and a risk analysis unit;

[0025] The combustible gas analysis unit is used to obtain the concentration of combustible gas and to perform explosion risk analysis based on real-time oxygen content and combustible gas concentration in order to identify whether there are false safety signals.

[0026] The risk analysis unit is used to analyze the root cause of the risk and generate an early warning when false security signals are present.

[0027] Furthermore, the combustible gas analysis unit includes an oxygen content change curve monitoring subunit, a curve analysis subunit, and a combustible gas concentration analysis subunit;

[0028] The oxygen content change curve monitoring subunit is used to obtain the real-time oxygen content change curve over time, thus obtaining the oxygen content change curve.

[0029] The curve analysis subunit is used to obtain the absolute value of the slope of the oxygen content change curve, obtain the real-time slope, and compare the real-time slope with the standard slope.

[0030] The combustible gas concentration analysis subunit is used to determine whether the operating status is normal or a false safety signal exists based on the comparison between the real-time combustible gas concentration and the first standard combustible gas concentration when the real-time slope is greater than the standard slope.

[0031] Furthermore, the risk analysis unit includes a combustible gas discrimination subunit, a rotation speed discrimination subunit, and a micro-negative pressure discrimination subunit;

[0032] The combustible gas discrimination subunit is used to compare the real-time combustible gas concentration with the second standard combustible gas concentration when a false safety signal is present.

[0033] The speed discrimination subunit is used to respond to the real-time combustible gas concentration being less than the second standard combustible gas concentration, and to determine whether to adjust the induced draft fan speed based on the comparison result between the real-time speed and the standard speed range;

[0034] The micro-negative pressure discrimination subunit is used to verify the micro-negative pressure in the drying equipment in response to the real-time rotation speed being within the standard rotation speed range, and to determine whether to reduce the preset heat source temperature or reduce the induced draft fan speed based on the verification result.

[0035] Furthermore, the risk analysis unit also includes an early warning subunit;

[0036] The early warning subunit includes a first early warning subunit, a second early warning subunit, and a third early warning subunit;

[0037] The first early warning subunit issues an alarm prompt for combustible gas release in response to a real-time combustible gas concentration being greater than or equal to the second standard combustible gas concentration.

[0038] The second early warning subunit issues an alarm indicating a seal failure when the real-time drying pressure exceeds the maximum value of the preset drying pressure range.

[0039] If the real-time rotational speed is greater than the second preset rotational speed, the third early warning subunit will issue an emergency stop alarm.

[0040] Furthermore, the oxygen content monitoring module also includes a combustible gas detector and a pressure sensor;

[0041] The combustible gas detector is installed on the upper part of the drying equipment or on the exhaust gas outlet pipe to monitor the concentration of combustible gas;

[0042] The pressure sensor is installed inside the drying equipment to monitor the real-time drying pressure inside the drying equipment.

[0043] Compared with existing technologies, the beneficial effects of this invention are as follows: by setting multiple oxygen content probes inside the drying equipment to monitor the oxygen concentration in different areas in real time, when any real-time oxygen content exceeds a first preset threshold, a risk is identified, and the inert gas protection module is immediately activated to control the opening of the nitrogen injection valve to inject nitrogen into the drying equipment. That is, the nitrogen interlock device will immediately inject nitrogen into the drying equipment to dilute and replace oxygen, quickly restoring the environment to an inert state. At the same time, by performing continuous leak diagnosis, the recovery curve of oxygen content is continuously analyzed. If it rises rapidly again after recovery, a continuous leak is identified, and the leak point is located. Different response strategies are implemented according to the location of the leak point. By analyzing the matching degree between the induced draft fan air volume and the system state, the operating parameters are automatically adjusted to keep the system in the optimal and most energy-efficient safety state. When the real-time oxygen content is less than or equal to the first preset threshold, it is analyzed whether there is a false appearance of a temporary decrease in oxygen content reading due to the dilution of combustible gas, thereby improving the system's ability to judge complex operating conditions, preventing problems before they occur, and ensuring system safety and energy saving. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the sludge drying system for precise oxygen content control according to an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the security status determination module according to an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of the protective effect monitoring module according to an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of the security status analysis module in an embodiment of the present invention. Detailed Implementation

[0048] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0049] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0050] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0051] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] Please see Figure 1 As shown, this is a schematic diagram of the sludge drying system for precise oxygen content control according to an embodiment of the present invention. The present invention provides a sludge drying system for precise oxygen content control, comprising:

[0053] An oxygen content monitoring module includes oxygen content probes installed at multiple monitoring points inside the drying equipment to obtain the real-time oxygen content at the monitoring points.

[0054] A safety status determination module, which is connected to the oxygen content monitoring module, is used to output a first prevention and control status signal or a second prevention and control status signal based on the comparison result between the real-time oxygen content and the first preset threshold.

[0055] An inert gas protection module, which is connected to the safety status determination module, is used to activate an emergency protection mode in response to the first prevention and control status signal, so as to inject inert gas into the drying equipment;

[0056] The protection effect monitoring module is connected to the oxygen content monitoring module and the inert gas protection module respectively. It is used to perform continuous leakage diagnosis after the inert gas protection module is activated, locate the leakage area based on the diagnosis results, and perform corresponding parameter optimization.

[0057] The safety status analysis module, which is connected to the safety status discrimination module, is used to respond to the second prevention and control status signal, perform explosion risk analysis based on real-time oxygen content and combustible gas concentration, and issue early warning prompts.

[0058] In this embodiment, multiple oxygen content probes are installed inside the drying equipment to monitor the oxygen concentration in different areas in real time. When any real-time oxygen content exceeds a first preset threshold, a risk is identified, and the inert gas protection module is immediately activated to control the nitrogen injection valve to inject nitrogen into the drying equipment. The nitrogen interlock device immediately injects nitrogen into the drying equipment to dilute and replace the oxygen, quickly restoring the environment to an inert state. Simultaneously, continuous leak diagnosis is performed, and the oxygen content recovery curve is continuously analyzed. If the oxygen content rises rapidly again after recovery, a continuous leak is identified, and the leak point is located. Different response strategies are implemented based on the leak location. Furthermore, by analyzing the matching degree between the induced draft fan airflow and the system state, operating parameters are automatically adjusted to ensure the system always remains in an optimal, energy-efficient, and safe state. When the real-time oxygen content is consistently less than or equal to the first preset threshold, the system analyzes whether there is a temporary decrease in oxygen content reading due to the dilution of combustible gas, thus improving the system's ability to judge complex operating conditions, preventing problems before they occur, and ensuring system safety and energy conservation.

[0059] See Figure 2 As shown, it is a structural schematic diagram of the security status discrimination module in an embodiment of the present invention;

[0060] Specifically, the security status determination module includes a first determination module and a second determination module;

[0061] The first discrimination module is used to issue a first prevention and control status signal when the real-time oxygen content monitored by any of the oxygen content probes is greater than a first preset threshold.

[0062] The second discrimination module is used to issue a second prevention and control status signal when the real-time oxygen content monitored by each of the oxygen content probes is less than or equal to the first preset threshold.

[0063] In this embodiment, the first preset threshold is the oxygen content safety threshold, set at 2%, requiring the oxygen content inside the drying equipment to be below 2% to avoid the possibility of dust explosion; the first prevention and control status signal is to activate the inert gas protection module to control the opening of the nitrogen injection valve to inject nitrogen into the drying equipment; the second prevention and control status signal is to proactively analyze potential risks by cross-validating the oxygen content and combustible gas concentration.

[0064] See Figure 3 As shown, it is a structural schematic diagram of the protection effect monitoring module of an embodiment of the present invention;

[0065] Specifically, the protection effect monitoring module includes a leakage analysis unit and a parameter optimization unit;

[0066] The leakage analysis unit is used to determine whether there is a continuous leakage point based on the comparison result between the real-time oxygen content and the first preset threshold, and if there is a continuous leakage point, to determine the area where the continuous leakage point is located based on the real-time oxygen content and real-time response time of each oxygen content probe.

[0067] The parameter optimization unit is used to issue a location alarm signal based on the area type where the continuous leakage point is located, or to optimize the operating parameters of the induced draft fan based on the comparison between the operating air volume and the theoretical air extraction volume of the induced draft fan.

[0068] Specifically, the leakage analysis unit includes a leakage determination subunit, a marking subunit, and a leakage point location subunit;

[0069] The leakage determination subunit is used to determine whether there is a first recovery moment and a second exceeding moment on the corresponding oxygen content recovery curve based on the comparison result between the real-time oxygen content of any monitoring point and the first preset threshold, so as to determine whether there is a continuous leakage point.

[0070] The marking subunit is used to mark the monitoring point as a target monitoring point when a persistent leak point exists;

[0071] The leak point location subunit determines the area where the continuous leak point is located based on the real-time oxygen content and real-time response time of the oxygen content probes at each of the target monitoring points.

[0072] The real-time response time is the time from the first recovery to the second time the threshold is exceeded.

[0073] The target monitoring point is the monitoring point closest to the point of continuous leakage among all monitoring points;

[0074] The first recovery time is the moment when the real-time oxygen content is less than or equal to the first preset threshold after the inert gas protection module is activated;

[0075] The second time exceeding the standard is the moment when the real-time oxygen content is greater than the first preset threshold after the first recovery time.

[0076] In this embodiment, by plotting the real-time oxygen content change curves of each monitoring point over time, a corresponding oxygen content recovery curve is obtained. The leakage determination subunit analyzes any oxygen content change curve. If the oxygen content recovery curve shows both an initial recovery time and a second time exceeding the limit, it is determined that a continuous leakage point exists at the monitoring point. The leakage point location subunit sequentially determines the area where the continuous leakage point corresponding to each target monitoring point is located according to the location analysis sequence, including:

[0077] The real-time oxygen content of each oxygen content probe is obtained, and the positioning and analysis order is determined according to the real-time oxygen content from high to low. The oxygen content probes are analyzed in sequence according to the positioning and analysis order.

[0078] Among them, the probe with the highest real-time oxygen content value is selected as the probe to be analyzed, and the area where the continuous leakage point is located is determined based on the real-time response time of the probe to be analyzed.

[0079] After the probe to be analyzed is completed, the oxygen content probes of the next priority in the sequence are analyzed one by one.

[0080] In this embodiment, by performing continuous leakage diagnosis, the readings and change sequence of multiple probes are analyzed, that is, the first recovery time and the second exceedance time on the oxygen content recovery curve are continuously analyzed to distinguish between random fluctuations and continuous leakage. For continuous leakage, the approximate leakage area is located, providing maintenance personnel with accurate maintenance guidance and improving the maintainability and operating efficiency of the system.

[0081] Specifically, the parameter optimization unit includes a matching analysis subunit and a parameter optimization subunit;

[0082] The matching analysis subunit is used to analyze the real-time matching degree between the induced draft fan and the theoretical air extraction volume required for the current evaporation of moisture and leakage gas, and obtain the analysis results;

[0083] The parameter optimization subunit is used to determine whether to adjust the induced draft fan speed based on the analysis results.

[0084] Specifically, the analysis examines the real-time matching degree between the induced draft fan and the theoretical extraction volume required for the current evaporation of moisture and leakage gas:

[0085] If the real-time matching degree is less than the first standard matching degree, the air volume is determined to be insufficient. The speed of the induced draft fan is increased by a preset step size until the real-time matching degree enters the standard matching degree range.

[0086] If the real-time matching degree is greater than or equal to the first standard matching degree and less than or equal to the second standard matching degree, the air volume is determined to be matched, and the current fan speed is maintained, which can achieve optimal operation in terms of safety and energy efficiency.

[0087] If the real-time matching degree is greater than the second standard matching degree, reduce the speed of the induced draft fan by the preset step size;

[0088] The theoretical air extraction capacity is the sum of the amount of steam generated by the current evaporation of moisture and the minimum amount of leakage air compensation required to maintain a slight negative pressure.

[0089] The minimum leakage air compensation is the product of the current amount of vapor generated by evaporating moisture and the leakage coefficient. The leakage coefficient is set between 3% and 10%, preferably 5%. The preset step size is 3% of the rated air volume of the induced draft fan, in m³ / h.

[0090] Real-time matching degree is the ratio of actual air extraction volume to theoretical air extraction volume;

[0091] In this embodiment, the areas where the continuous leakage point is located include the inlet area, the outlet area, the vicinity of the main shaft seal, the upper, middle, and lower parts of the internal space of the equipment, the downstream of the airflow path, and the area before the induced draft fan inlet. The types of areas where the continuous leakage point is located include Class I and Class II areas. Class I areas are high-risk monitoring areas where potential leakage points are located, including the inlet area, the outlet area, and the vicinity of the main shaft seal. Class II areas are areas other than the inlet area, the outlet area, or areas other than the vicinity of the main shaft seal. If the area where the continuous leakage point is located is determined to be a Class I area, an alarm is triggered. If the area where the continuous leakage point is located is determined to be a Class II area, the operating airflow of the induced draft fan is analyzed, and the operating parameters of the induced draft fan are optimized based on the analysis results. The first standard matching degree is 1.05, the second standard matching degree is 1.20, and when the real-time matching degree is greater than... When the real-time matching degree is equal to the first standard matching degree and less than or equal to the second standard matching degree, it means that the air volume of the induced draft fan is slightly greater than the amount of air required to evaporate moisture and a small amount of leaked gas. At this time, the induced draft fan can just remove the water vapor generated by the process and draw in just enough air to maintain the set micro negative pressure, thus theoretically controlling the external leakage to the minimum and most controllable amount. If the real-time matching degree is less than the first standard matching degree, it means that the air volume is insufficient and cannot reliably maintain the micro negative pressure. The initial induced draft fan speed needs to be increased. The increased induced draft fan speed is the sum of the initial induced draft fan speed and the preset step size. If the real-time matching degree is greater than the second standard matching degree, it means that the air volume is too large and the energy consumption is too high. In this case, the initial induced draft fan speed is reduced to save energy. The reduced induced draft fan speed is the difference between the initial induced draft fan speed and the preset step size, which responds more precisely to different operating states and achieves the best balance between safety, stability and energy efficiency.

[0092] See Figure 4 As shown, it is a structural schematic diagram of the security status analysis module in an embodiment of the present invention;

[0093] Specifically, the safety status analysis module includes a combustible gas analysis unit and a risk analysis unit;

[0094] The combustible gas analysis unit is used to obtain the concentration of combustible gas and to perform explosion risk analysis based on real-time oxygen content and combustible gas concentration in order to identify whether there are false safety signals.

[0095] The risk analysis unit is used to analyze the root cause of the risk and generate an early warning when false security signals are present.

[0096] In this embodiment, the false safety signal is a signal generated by the illusion of a temporary decrease in oxygen content reading due to the dilution of combustible gas. In areas with a high concentration of combustible gas release, the oxygen in the air will be locally diluted, causing the oxygen content reading to temporarily decrease. However, since the area is actually filled with a combustible mixture, the risk of explosion is higher. Therefore, when the oxygen content is normal, proactively analyzing potential risks and cross-validating the oxygen content and combustible gas concentration can effectively identify the dangerous illusion of a temporary decrease in oxygen content reading due to the dilution of combustible gas, thereby improving the system's ability to judge complex operating conditions and preventing problems before they occur.

[0097] Specifically, the combustible gas analysis unit includes an oxygen content change curve monitoring subunit, a curve analysis subunit, and a combustible gas concentration analysis subunit;

[0098] The oxygen content change curve monitoring subunit is used to obtain the real-time oxygen content change curve over time, thus obtaining the oxygen content change curve.

[0099] The curve analysis subunit is used to obtain the absolute value of the slope of the oxygen content change curve, to obtain the real-time slope, and to compare the real-time slope with the standard slope:

[0100] If the real-time slope is less than or equal to the standard slope, the operation is considered normal.

[0101] The combustible gas concentration analysis subunit is used to determine whether the operating status is normal or there is a false safety signal when the real-time slope is greater than the standard slope, based on the comparison between the real-time combustible gas concentration and the first standard combustible gas concentration.

[0102] Compare the real-time combustible gas concentration with the first standard combustible gas concentration:

[0103] If the real-time combustible gas concentration is less than the first standard combustible gas concentration, the operating status is determined to be normal.

[0104] If the real-time combustible gas concentration is greater than or equal to the first standard combustible gas concentration, it is determined that a false safety signal exists.

[0105] In this embodiment, the standard slope is the threshold value for a rapid decrease in the instantaneous rate of oxygen content change, set at 0.1% / s. When the real-time slope is greater than the standard slope, it is determined that the oxygen content is rapidly decreasing. By comparing the real-time combustible gas concentration with the first standard combustible gas concentration, fluctuations are distinguished from risks. The first standard combustible gas concentration is a false safety confirmation threshold used to confirm whether the abnormal decrease in oxygen content is caused by combustible gas release, thus distinguishing fluctuations from risks. The monitored combustible gas is methane, and the first standard combustible gas concentration is set at 0.5% VOL. When the real-time combustible gas concentration is greater than or equal to the first standard combustible gas concentration, it indicates that the decrease in oxygen content is due to combustible gas dilution, and the severity of combustible gas release needs to be further determined.

[0106] Specifically, the risk analysis unit includes a combustible gas discrimination subunit, a rotation speed discrimination subunit, and a micro-negative pressure discrimination subunit;

[0107] The combustible gas discrimination subunit is used to compare the real-time combustible gas concentration with the second standard combustible gas concentration when a false safety signal is present.

[0108] The speed discrimination subunit is used to respond to the real-time combustible gas concentration being less than the second standard combustible gas concentration, and to determine whether to adjust the induced draft fan speed based on the comparison result between the real-time speed and the standard speed range;

[0109] The micro-negative pressure discrimination subunit is used to verify the micro-negative pressure in the drying equipment in response to the real-time rotation speed being within the standard rotation speed range, and to determine whether to reduce the preset heat source temperature or reduce the induced draft fan speed based on the verification result.

[0110] In this embodiment, when a false safety signal is present, the combustible gas discrimination subunit compares the real-time combustible gas concentration with the second standard combustible gas concentration: if the real-time combustible gas concentration is greater than or equal to the second standard combustible gas concentration, the first early warning subunit issues an alarm prompt for combustible gas release; if the real-time combustible gas concentration is less than the second standard combustible gas concentration, the speed discrimination subunit compares the standard speed range with the real-time speed: if the real-time speed is within the standard speed range, the micro-negative pressure discrimination subunit initiates micro-negative pressure verification.

[0111] The micro-negative pressure verification process is as follows: The real-time drying pressure is obtained by a pressure sensor installed inside the thin-layer drying equipment. The real-time drying pressure is judged according to the preset drying pressure range: If the real-time drying pressure is within the preset drying pressure range, the preset heat source temperature is reduced; if the real-time drying pressure is not within the preset drying pressure range, the real-time drying pressure is compared with the preset drying pressure range: If the real-time drying pressure is greater than the maximum value of the preset drying pressure range, the seal is judged to be in failure; if the real-time drying pressure is less than the minimum value of the preset drying pressure range, the induced draft fan speed is appropriately reduced.

[0112] The preset heat source temperature is 160℃. Lowering the preset heat source temperature uses a stepped cooling method. First, the heat source temperature is reduced by 10℃ from the current value to 150℃. The combustible gas concentration is continuously monitored. If the concentration does not show a significant decreasing trend within 3-5 minutes, the heat source temperature is reduced again by 10℃ to 140℃. The minimum lower limit is 130℃. When the temperature drops to the lower limit but the combustible gas concentration is still not under control, the system will upgrade to an emergency shutdown alarm. Reducing the induced draft fan speed uses a small step adjustment. The preset step size is 3% of the rated airflow of the induced draft fan. If the rated airflow is 20,000 m³ / h, the step size is 600 m³ / h. The current induced draft fan speed is 1200 rpm. Converting the airflow step size to the speed step size, 100 m³ / h corresponds to 6 rpm, and a step size of 600 m³ / h corresponds to a reduction of 36 rpm. The induced draft fan speed is reduced by 36 rpm from the current value to 1164 rpm. After adjustment, the pressure is continuously monitored. If the pressure still does not return to above -500Pa, it will be reduced by 36 rpm again in the next control cycle (1 minute later) until the slight negative pressure returns to the normal range.

[0113] If the real-time speed is not within the standard speed range, the speed determination subunit judges the real-time speed based on the first preset speed and the second preset speed to determine whether to adjust the real-time speed: if the real-time speed is less than the first preset speed, the real-time speed is adjusted; if the real-time speed is greater than the second preset speed, the third early warning subunit performs an emergency shutdown to prevent equipment damage and increased risk of dust explosion.

[0114] In this embodiment, the preset drying pressure range represents a micro-negative pressure range. The set value is affected by the specifications of the drying machine and the characteristics of the wet sludge. Generally, the preset drying pressure range is set between -500 Pa and -100 Pa, and is adjusted according to the actual wet sludge processing volume and drying requirements. The second standard combustible gas concentration is used as the decision threshold for determining whether to immediately sound a loud alarm or respond to the risk classification of troubleshooting after confirming false safety. The second standard combustible gas concentration is 2.0% VOL. When the real-time combustible gas concentration is greater than or equal to the second standard combustible gas concentration, it indicates that the combustible gas release is serious and close to the dangerous level. In this case, the highest level of audible and visual alarm for combustible gas release is issued to prompt the operator to intervene urgently. When the real-time combustible gas concentration is less than the second standard combustible gas concentration, it indicates that the risk exists but has not reached the critical point. The rotation speed and micro-negative pressure are checked in sequence, and the root cause of the problem is automatically repaired, which improves the intelligence level and reliability of safety protection.

[0115] Because when the rotor speed is too low, it will cause uneven sludge coating and localized thickening of the sludge, which will worsen heat transfer, cause localized heat accumulation, and cause the temperature of the bottom sludge to rise sharply and exceed the pyrolysis threshold, thus causing the sludge to pyrolyze and release a large amount of combustible gas. This will cause the system to show a false safety signal of oxygen content due to the dilution of combustible gas, which will increase the risk of explosion. Therefore, by checking the rotation speed and verifying the micro-negative pressure when the real-time combustible gas concentration is less than the second standard combustible gas concentration, the generation of combustible gas can be curbed from the source by reducing the heat source temperature.

[0116] Specifically, the risk analysis unit also includes an early warning subunit;

[0117] The early warning subunit includes a first early warning subunit, a second early warning subunit, and a third early warning subunit;

[0118] The first early warning subunit issues an alarm prompt for combustible gas release in response to a real-time combustible gas concentration being greater than or equal to the second standard combustible gas concentration.

[0119] The second early warning subunit issues an alarm indicating a seal failure when the real-time drying pressure exceeds the maximum value of the preset drying pressure range.

[0120] If the real-time rotation speed is greater than the second preset rotation speed, the third early warning subunit will issue an emergency shutdown alarm to prevent equipment damage and increased risk of dust explosion.

[0121] Specifically, the oxygen content monitoring module also includes a combustible gas detector and a pressure sensor;

[0122] The combustible gas detector is installed on the upper part of the drying equipment or on the exhaust gas outlet pipe to monitor the concentration of combustible gas;

[0123] The pressure sensor is installed inside the drying equipment to monitor the real-time drying pressure inside the drying equipment.

[0124] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0125] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sludge drying system for precise control of oxygen content, characterized in that, include: An oxygen content monitoring module includes oxygen content probes installed at multiple monitoring points inside the drying equipment to obtain the real-time oxygen content at the monitoring points. A safety status determination module, which is connected to the oxygen content monitoring module, is used to output a first prevention and control status signal or a second prevention and control status signal based on the comparison result between the real-time oxygen content and the first preset threshold. An inert gas protection module, which is connected to the safety status determination module, is used to activate an emergency protection mode in response to the first prevention and control status signal, so as to inject inert gas into the drying equipment; The protection effect monitoring module is connected to the oxygen content monitoring module and the inert gas protection module respectively. It is used to perform continuous leakage diagnosis after the inert gas protection module is activated, locate the leakage area based on the diagnosis results, and perform corresponding parameter optimization. A safety status analysis module, which is connected to the safety status discrimination module, is used to respond to the second prevention and control status signal, perform explosion risk analysis based on real-time oxygen content and combustible gas concentration, and issue early warning prompts. The safety status analysis module includes a combustible gas analysis unit and a risk analysis unit; The combustible gas analysis unit is used to obtain the concentration of combustible gas and to perform explosion risk analysis based on real-time oxygen content and combustible gas concentration in order to identify whether there are false safety signals. The risk analysis unit is used to analyze the root cause of the risk and generate an early warning when false security signals are present; The combustible gas analysis unit includes an oxygen content change curve monitoring subunit, a curve analysis subunit, and a combustible gas concentration analysis subunit; The oxygen content change curve monitoring subunit is used to obtain the real-time oxygen content change curve over time, thus obtaining the oxygen content change curve. The curve analysis subunit is used to obtain the absolute value of the slope of the oxygen content change curve, obtain the real-time slope, and compare the real-time slope with the standard slope. The combustible gas concentration analysis subunit is used to determine whether the operating status is normal or there is a false safety signal when the real-time slope is greater than the standard slope, based on the comparison between the real-time combustible gas concentration and the first standard combustible gas concentration. The risk analysis unit includes a combustible gas discrimination subunit, a rotation speed discrimination subunit, and a micro-negative pressure discrimination subunit; The combustible gas discrimination subunit is used to compare the real-time combustible gas concentration with the second standard combustible gas concentration when a false safety signal is present. The speed discrimination subunit is used to respond to the real-time combustible gas concentration being less than the second standard combustible gas concentration, and to determine whether to adjust the induced draft fan speed based on the comparison result between the real-time speed and the standard speed range; The micro-negative pressure discrimination subunit is used to verify the micro-negative pressure in the drying equipment in response to the real-time rotation speed being within the standard rotation speed range, and to determine whether to reduce the preset heat source temperature or reduce the induced draft fan speed based on the verification result. The risk analysis unit also includes an early warning subunit; The early warning subunit includes a first early warning subunit, a second early warning subunit, and a third early warning subunit; The first early warning subunit issues an alarm prompt for combustible gas release in response to a real-time combustible gas concentration being greater than or equal to the second standard combustible gas concentration. The second early warning subunit issues an alarm indicating a seal failure when the real-time drying pressure exceeds the maximum value of the preset drying pressure range. If the real-time rotational speed is greater than the second preset rotational speed, the third early warning subunit will issue an emergency stop alarm.

2. The sludge drying system for precise oxygen content control according to claim 1, characterized in that, The security status determination module includes a first determination module and a second determination module; The first discrimination module is used to issue a first prevention and control status signal when the real-time oxygen content monitored by any of the oxygen content probes is greater than a first preset threshold. The second discrimination module is used to issue a second prevention and control status signal when the real-time oxygen content monitored by each of the oxygen content probes is less than or equal to the first preset threshold.

3. The sludge drying system for precise oxygen content control according to claim 1, characterized in that, The protection effect monitoring module includes a leakage analysis unit and a parameter optimization unit; The leakage analysis unit is used to determine whether there is a continuous leakage point based on the comparison result between the real-time oxygen content and the first preset threshold, and if there is a continuous leakage point, to determine the area where the continuous leakage point is located based on the real-time oxygen content and real-time response time of each oxygen content probe. The parameter optimization unit is used to issue a location alarm signal based on the area type where the continuous leakage point is located, or to optimize the operating parameters of the induced draft fan based on the comparison between the operating air volume and the theoretical air extraction volume of the induced draft fan.

4. The sludge drying system for precise oxygen content control according to claim 3, characterized in that, The leakage analysis unit includes a leakage determination subunit, a marking subunit, and a leakage point location subunit; The leakage determination subunit is used to determine whether there is a first recovery moment and a second exceeding moment on the corresponding oxygen content recovery curve based on the comparison result between the real-time oxygen content of any monitoring point and the first preset threshold, so as to determine whether there is a continuous leakage point. The marking subunit is used to mark the monitoring point as a target monitoring point when a persistent leak point exists; The leak point location subunit determines the area where the continuous leak point is located based on the real-time oxygen content and real-time response time of the oxygen content probes at each of the target monitoring points.

5. The sludge drying system for precise oxygen content control according to claim 3, characterized in that, The parameter optimization unit includes a matching analysis subunit and a parameter optimization subunit; The matching analysis subunit is used to analyze the real-time matching degree between the induced draft fan and the theoretical air extraction volume required for the current evaporation of moisture and leakage gas, and obtain the analysis results; The parameter optimization subunit is used to determine whether to adjust the induced draft fan speed based on the analysis results.

6. The sludge drying system for precise oxygen content control according to claim 1, characterized in that, The oxygen content monitoring module also includes a combustible gas detector and a pressure sensor; The combustible gas detector is installed on the upper part of the drying equipment or on the exhaust gas outlet pipe to monitor the concentration of combustible gas; The pressure sensor is installed inside the drying equipment to monitor the real-time drying pressure inside the drying equipment.

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