Graded inerting device and method based on dynamic risk discrimination

Abstract

The invention discloses a graded inerting device and method based on dynamic risk discriminating.The device comprises a continuous inerting system, a dust removal system and an efficient inerting system, the dust removal system comprises a dust removal main pipeline and a dust remover which are connected, the continuous inerting system comprises an inerting dust bin and feeding equipment, and the feeding equipment is connected with the dust removal main pipeline; the efficient inerting system comprises an efficient inerting powder tank; and the efficient inerting powder tank is connected with a dust remover. According to the method, the continuous inerting system and the efficient inerting system are used in a combined mode, the explosion risk of the main dust removal pipeline can be reduced through the continuous inerting system under the condition that the dust remover does not break down, and meanwhile the combustible dust explosion risk caused by the fault of the dust remover can be effectively controlled; the efficient inerting system is only triggered under the abnormal condition that the dust concentration of the dust remover is abnormally increased or explosion is generated, so that the energy consumption of fixed threshold inerting and the consumption of an inerting medium are effectively reduced, and more efficient inerting is realized.

Description

Technical Field

[0001] This invention relates to the field of dust inerting technology, and in particular to a graded inerting device and method based on dynamic risk assessment. Background Technology

[0002] In many industrial sectors such as petrochemicals, coal chemicals, and metal processing, there are large-scale production, storage, and handling processes involving combustible dust. Once this dust mixes with air and reaches its explosive limit, it can easily cause catastrophic accidents such as fires and explosions upon encountering an ignition source, seriously threatening the safety of people and property. Inerting technology, as an important means of active explosion prevention and suppression, eliminates or significantly reduces the explosion risk of combustible mixtures by injecting inert gas or inert dust into the protected space.

[0003] In current industrial production, the inerting of combustible dust mainly adopts a fixed threshold inerting system. This system continuously injects a fixed concentration of inert dust or inert gas into the protected area during operation by setting a single inerting medium concentration threshold. However, the traditional fixed threshold mode can hardly meet the requirements of precision and efficiency in modern dust explosion prevention and control.

[0004] Based on the above analysis, the problems and shortcomings of the existing technology are as follows:

[0005] (1) The currently widely used fixed threshold control system continuously injects inert dust or inert gas under normal operating conditions. The consumption of inert dust and inert gas is large and energy is high. Moreover, when the dust concentration changes significantly or exceeds the lower explosion limit, it is difficult to quickly achieve inertization and there is still an explosion risk.

[0006] (2) At present, the inerting scheme of the dust removal system can only control the operating concentration in the conventional pipeline, and the control of dust cloud caused by dust accumulation or dust collector failure is weak. Summary of the Invention

[0007] The first objective of this invention is to propose a hierarchical inertization device based on dynamic risk assessment.

[0008] The present invention adopts the following technical solution:

[0009] A graded inerting device based on dynamic risk assessment includes a continuous inerting system, a dust removal system, and a high-efficiency inerting system. The dust removal system includes a main dust removal pipeline and a dust collector connected to each other. The continuous inerting system includes an inerting dust silo and a feeding device connected to the main dust removal pipeline. The high-efficiency inerting system includes a high-efficiency inerting powder tank connected to the dust collector.

[0010] Preferably, the main dust removal pipeline is connected to multiple dust removal branch pipes, each dust removal branch pipe is equipped with a first dust concentration sensor, the end of the main dust removal pipeline near the dust collector is equipped with a second dust concentration sensor, one end of the main dust removal pipeline is connected to the feeding equipment through a check valve, and the end of the main dust removal pipeline near the check valve is equipped with a third dust concentration sensor; a pressure sensor is installed in the dust collector.

[0011] Preferably, the inerting dust silo is equipped with a stirring motor and a stirring vessel, and the feeding equipment includes a screw feeder connected to the bottom of the inerting dust silo. The screw feeder is connected to a Venturi injector, which is connected to a high-pressure blower. The Venturi injector is connected to a check valve through a pipeline.

[0012] Preferably, multiple high-efficiency inerting powder tanks are provided, each containing high-pressure inert gas and inert dust, and the high-efficiency inerting powder tanks are connected to the dust collector via pneumatic valves.

[0013] Preferably, it also includes a main controller, which is electrically connected to the first dust concentration sensor, the second dust concentration sensor, the third dust concentration sensor, the pressure sensor, the stirring motor, and the high-pressure blower.

[0014] The second objective of this invention is to propose a graded inerting method based on dynamic risk assessment to address the problems of high consumption of inerting powder or gas, high system energy consumption, and untimely inerting under high-risk conditions in existing dust removal system inerting methods. This will improve the safety of the dust removal process, reduce the operating cost of the inerting system, and increase inerting efficiency.

[0015] A hierarchical inertia method based on dynamic risk assessment, applied to the aforementioned hierarchical inertia device based on dynamic risk assessment, includes the following steps:

[0016] Step 1: The main controller acquires the value from the first dust concentration sensor. , Let i be the dust concentration value of the first dust concentration sensor, according to The average dust concentration in the main dust collection pipeline was calculated. ;

[0017] (1);

[0018] in, The air volume of the main dust removal duct is in m³ / h. Let be the air volume of the i-th dust removal branch pipe, in m³ / h;

[0019] Set the threshold for graded dust concentration , , , , respectively:

[0020] (2);

[0021] (3);

[0022] (4);

[0023] Where MEC is the lower explosive limit concentration of dust, in g / m³;

[0024] When the main controller detects When the continuous inertization system does not start; when At that time, the continuous inerting system starts, and inerting dust is fed into the main dust collection duct. The continuous inerting system performs the first stage of continuous inerting, and the concentration of inerting dust in the first stage is [missing information]. ;

[0025] (5);

[0026] Minimum inert dust concentration, wt% The dust concentration safety factor is greater than 1;

[0027] when At that time, the continuous inerting system performs secondary continuous inerting, and the inerting dust concentration during the secondary continuous inerting is... ;

[0028] (6);

[0029] when At that time, the continuous inerting system performs three-stage continuous inerting, and the inerting dust concentration during the three-stage continuous inerting is... ;

[0030] (7);

[0031] , and Detected by a third dust concentration sensor;

[0032] Step 2: The main controller calculates the concentration difference of combustible dust in the main dust removal duct. Specifically:

[0033] (8);

[0034] in, The dust concentration near the dust collector end is detected by the second dust concentration sensor, whereby... for or or ;

[0035] Set the risk threshold for combustible dust concentration as for:

[0036] (9);

[0037] when At that time, the high-efficiency inerting system is activated to fill the dust collector with high-pressure inert gas and inert dust from at least one high-efficiency inerting powder tank;

[0038] Step 3: The main controller acquires the pressure sensor values ​​in real time. Set pressure threshold ,when At this time, the efficient inertization system is not activated;

[0039] when At that time, the rate of pressure increase With the set pressure rise rate threshold In contrast, when When the high-efficiency inerting system is activated, the high-pressure inert gas and inert dust from at least one high-efficiency inerting powder tank are introduced into the dust collector; when At this time, the efficient inertization system is not activated;

[0040] in, for:

[0041] (10);

[0042] in, This represents the maximum floating pressure during normal operation of the dust collector, in MPa. Safety margin pressure, MPa;

[0043] (11);

[0044] in, The safety factor for the rate of pressure rise is <0.5; For the volume of the dust collector, m 3 ; The dust explosion index is expressed in bar·m / s.

[0045] It can be obtained by the main controller through the change value of the pressure sensor per unit time.

[0046] The beneficial effects of this invention are:

[0047] The present invention relates to a graded inerting method based on dynamic risk assessment. This method uses dust sensors installed on the main and branch pipes of the dust collector to monitor dust concentration in real time, and pressure sensors installed on the dust collector to monitor pressure within the dust collector in real time. The main controller analyzes and judges the system's hazard level using the proposed graded inerting calculation and comparison method. When the continuous inerting system is activated, graded continuous inerting can be performed. When the difference in combustible dust concentration in the main dust collector pipe is greater than or equal to a set risk threshold, the high-efficiency inerting system is activated to achieve complete inerting in a very short time, preventing an explosion. Alternatively, when the pressure sensor value exceeds the set risk threshold, the pressure rise rate is further assessed. If the pressure rise rate also exceeds the set risk threshold, the high-efficiency inerting system is activated, improving the accuracy of the assessment and achieving inerting and explosion suppression in a very short time, reducing the risk of explosion. The activation and deactivation of the continuous inerting system have no effect on the activation of the high-efficiency inerting system; the two are relatively independent. It has a feedback mechanism. If the continuous inertia system is turned on, it will continuously conduct a new round of monitoring, comparison and judgment. If the judgment result changes, it can shut down the continuous inertia system or increase the continuous inertia level in a timely manner, so as to reduce resource waste while achieving effective inertia.

[0048] This method combines a continuous inerting system with a high-efficiency inerting system. The continuous inerting system reduces the explosion risk of the main dust collection duct when the dust collector is functioning correctly, while effectively controlling the risk of combustible dust explosions caused by dust collector malfunctions. The high-efficiency inerting system is only triggered in cases of abnormally high dust concentration or when an explosion has already occurred. This effectively reduces the energy consumption and inerting medium consumption of fixed-threshold inerting, achieving more efficient inerting. The high-efficiency inerting system uses high-pressure inert gas and inert dust. During activation, both are simultaneously introduced into the dust collector for synergistic inerting, resulting in a more significant and efficient inerting effect. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the startup process of the continuous inertization system and the efficient inertization system of this invention.

[0050] Figure 2 This is a flowchart of the real-time monitoring and hierarchical inertization process of the present invention.

[0051] Figure 3 This is a schematic diagram of the hierarchical inertization device based on dynamic risk assessment according to the present invention.

[0052] Figure 3The components are as follows: 1. Agitator motor; 2. Inerting dust hopper; 3. Powder level sensor; 4. Stepper motor; 5. High-pressure blower; 6. Screw feeder; 7. Venturi ejector; 8. Check valve; 9. Main controller; 10. Dust collection main pipeline; 11. First dust concentration sensor; 12. Second dust concentration sensor; 13. Dust collector; 14. Pressure sensor; 15. High-efficiency inerting powder tank; 16. Pneumatic valve; 17. Pressure gauge; 18. Third dust concentration sensor. Detailed Implementation

[0053] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and specific examples:

[0054] Example 1

[0055] Combination Figure 3 A graded inerting device based on dynamic risk assessment includes a continuous inerting system, a dust removal system, and a high-efficiency inerting system.

[0056] The dust removal system includes a main dust removal pipeline 10 and a dust collector 13 connected together. The continuous inerting system includes an inerting dust silo 2 and a feeding device. The feeding device is connected to the main dust removal pipeline 10. The high-efficiency inerting system includes a high-efficiency inerting powder tank 15, which is connected to the dust collector 13.

[0057] Multiple dust collection branch pipes are connected to the main dust collection pipe 10. Each branch pipe is equipped with a first dust concentration sensor 11. A second dust concentration sensor 12 is installed near the dust collector end of the main dust collection pipe 10. One end of the main dust collection pipe is connected to the feeding equipment via a check valve 8, and a third dust concentration sensor 18 is installed near the check valve end of the main dust collection pipe. A pressure sensor 14 is installed inside the dust collector to monitor the pressure inside the dust collector in real time. The changes.

[0058] The inerting dust silo 2 contains inerting dust. The inerting dust silo 2 is equipped with a stirring motor 1 and a stirring vessel. The stirring motor 1 drives the stirring vessel to stir the inerting dust, so that the inerting dust in the inerting dust silo 2 can enter the screw feeder 6.

[0059] The feeding equipment includes a screw feeder 6, which is connected to the bottom of the inerting dust silo. The screw feeder 6 is connected to a Venturi ejector 7. The screw feeder 6 is driven to rotate by a stepper motor 4, feeding the inerting powder into the Venturi ejector 7. The Venturi ejector 7 is connected to a high-pressure blower 5, and the Venturi ejector 7 is connected to a check valve through a pipeline. The air blown by the high-pressure blower 5 blows the inerting dust in the Venturi ejector 7 into the main dust collection pipeline 10.

[0060] When the continuous inerting system is turned on, the check valve 8 is turned on; when the continuous inerting system is turned off, the check valve 8 is turned off, to prevent combustible dust in the main dust removal pipeline 10 from flowing back into the continuous inerting system.

[0061] A powder level sensor 3 is installed on the inerting dust hopper 2 to monitor the remaining amount of inerting dust in the hopper. When the level falls below the set value, an alarm is triggered, allowing operators to replenish the inerting powder in a timely manner. The output concentration of inerting dust is mainly controlled by the rotation speed of the screw feeder 6 by the stepper motor 4 and the air volume by the high-pressure blower 5. The stirring motor 1, powder level sensor 3, stepper motor 4, and high-pressure blower 5 are connected to the main controller 9 for real-time monitoring and control of the equipment.

[0062] The high-efficiency inerting powder tank contains high-pressure inert gas and inert dust, and is connected to the dust collector 13 via a pneumatic valve 16.

[0063] The high-efficiency inerting powder tank 15 is also connected to a pressure gauge 17. The pneumatic valve can be opened quickly, and the powder inerting agent is quickly charged into the dust collector by the high-pressure inert gas in the tank. The pressure gauge 17 monitors the pressure in the high-efficiency inerting powder tank 15 to ensure that the pressure is within the effective range.

[0064] Multiple high-efficiency inerting powder tanks 15 can be set according to actual inerting needs. In this specific embodiment, two high-efficiency inerting powder tanks are set, one of which is a spare powder tank to prevent the other powder tank from malfunctioning and to prevent the risk of explosion again after one of the powder tanks has been used. The pneumatic valve 16 and pressure gauge 17 are connected to the main controller 9 to facilitate real-time monitoring and control of the high-efficiency inerting equipment.

[0065] The main controller 9 is electrically connected to the first dust concentration sensor 11, the second dust concentration sensor 12, the third dust concentration sensor 18, and the pressure sensor 14.

[0066] Example 2

[0067] Combination Figures 1 to 3 A hierarchical inertia method based on dynamic risk assessment, applied to the hierarchical inertia device based on dynamic risk assessment described in Example 1, includes the following steps:

[0068] Step 1: The main controller acquires the value from the first dust concentration sensor. , Let i be the dust concentration value of the first dust concentration sensor, according to The average dust concentration in the main dust collection pipeline was calculated. ;

[0069] (1);

[0070] in, The air volume of the main dust removal duct is in m³ / h. Let be the air volume of the i-th dust removal branch pipe, in m³ / h.

[0071] In this embodiment, the combustible dust is aluminum powder, and there are three dust collection branch pipes. The aluminum dust concentration values ​​C1, C2, and C3 detected by the three first dust concentration sensors are used to determine the branch pipe airflow and Q1, Q2, and Q3. main The average aluminum dust concentration in the main dust collector duct is calculated using the main air volume and formula (1). .

[0072] Set the threshold for graded dust concentration , , , , respectively:

[0073] (2).

[0074] (3).

[0075] (4).

[0076] Wherein, MEC is the lower explosive limit concentration of dust, in g / m³. In this embodiment, the minimum explosive concentration (MEC) of aluminum powder is 30-50 g / m³, and the minimum value is taken for safety considerations. .

[0077] Calculated according to formulas (2) to (4): .

[0078] In this embodiment, when the main controller detects At this time, the continuous inertization system will not start.

[0079] In this embodiment, when At that time, the continuous inerting system starts, and inerting dust is fed into the main dust collection duct. The continuous inerting system performs the first stage of continuous inerting, and the concentration of inerting dust in the first stage is [missing information]. ;

[0080] (5).

[0081] Minimum inert dust concentration, wt% The dust concentration safety factor is greater than 1.

[0082] In this embodiment, when inerting is performed using dust, the inerting concentration is usually expressed as the mixing ratio of inert dust and combustible dust. The most commonly used specific parameter is the minimum inert dust concentration (MIC), which refers to the minimum mass fraction of inert dust required to completely prevent the combustible dust-air mixture from exploding under specific conditions. Its unit is mass fraction (wt%) or mass ratio. Calcium carbonate (CaCO3) is widely available, low in cost, and non-toxic. CaCO3 is selected as the inert dust, and the MIC is set to 60%.

[0083] It should be noted that the minimum inert dust concentration (MIC) is not a fixed value. It varies depending on factors such as the characteristics of aluminum powder, the particle size of calcium carbonate, and experimental conditions. The approximate reference range may be above 50% (mass fraction). The finer the particle size, the lower the required MIC may be. However, it is essential to determine the exact value through experiments.

[0084] SF (safety factor) is a dimensionless number used to measure the safety margin of a system, structure, or component; it is the ratio between the system's ultimate capacity and the expected maximum workload. The larger the value, the higher the safety margin. The value can be appropriately selected based on the level of system risk. Here, it is set to... =1.1.

[0085] According to formula (5), the result is: .

[0086] In this embodiment, when At that time, the continuous inerting system performs secondary continuous inerting, and the inerting dust concentration during the secondary continuous inerting is... ;

[0087] (6).

[0088] Calculated .

[0089] In this embodiment, when At that time, the continuous inerting system performs three-stage continuous inerting, and the inerting dust concentration during the three-stage continuous inerting is... ;

[0090] (7).

[0091] At this point, because the aluminum powder concentration exceeds the lower explosive limit, the risk is high. Therefore, the continuous inerting system no longer uses a fixed inerting dust concentration for inerting, but instead calculates the required inerting dust concentration in real time according to formula (7). It is not a fixed value. The value varies with the concentration of combustible dust in the main pipeline. It changes with the changes.

[0092] , and The concentration was determined by the third dust concentration sensor.

[0093] After each monitoring, calculation, judgment, and instruction issuance, a new round of monitoring and judgment will be carried out to monitor the changes in dust concentration in the pipeline in real time, and to promptly turn the continuous inerting system on or off or change the continuous inerting level according to the changes in dust concentration, so as to achieve dynamic and efficient inerting.

[0094] Step 2: The main controller calculates the concentration difference of combustible dust in the main dust removal duct. Specifically:

[0095] (8).

[0096] in, The dust concentration near the dust collector end is detected by the second dust concentration sensor, whereby... for or or .

[0097] Set the risk threshold for combustible dust concentration as for:

[0098] (9).

[0099] when When the high-efficiency inerting system is activated, the high-pressure inert gas and inert dust from at least one high-efficiency inerting powder tank are introduced into the dust collector.

[0100] Will With set value In comparison, in this embodiment, when The efficient inerting system is activated when the dust concentration difference is not reached, and otherwise the dust concentration difference is monitored and judged.

[0101] Step 3: The main controller acquires the pressure sensor values ​​in real time. Set pressure threshold ,when At that time, the efficient inertization system is not activated.

[0102] in, for:

[0103] (10).

[0104] in, This represents the maximum floating pressure during normal operation of the dust collector, in MPa. For safety margin pressure, MPa.

[0105] In this embodiment, the maximum floating pressure during normal operation of the dust collector is... Based on actual observations, this is taken here. Safety margin pressure Considering the pressure fluctuations caused by the activation of the high-efficiency inerting system, and to prevent the activation of the high-efficiency inerting system from triggering further damage, here we take... .

[0106] when At that time, the rate of pressure increase With the set pressure rise rate threshold Comparison. In this embodiment, when At that time, a dual-judgment process is initiated to further determine the real-time pressure rise rate. Is it greater than .

[0107] when When the high-efficiency inerting system is activated, the high-pressure inert gas and inert dust from at least one high-efficiency inerting powder tank are introduced into the dust collector; when At this time, the efficient inertization system is not activated;

[0108] (11).

[0109] in, The safety factor for the rate of pressure rise is <0.5; For the volume of the dust collector, m 3 ; The dust explosion index is expressed in bar·m / s.

[0110] It can be obtained by the main controller through the change value of the pressure sensor per unit time.

[0111] In this embodiment, a safety factor for the pressure rise rate is used. Dust collector volume Aluminum dust explosion index The explosion pressure is related to various factors such as aluminum powder particle size, concentration, and ignition energy. In practical applications, the explosion pressure will vary depending on the specific circumstances. Table 1 shows the Kst values ​​of some aluminum powders under specific laboratory conditions. Here, we select a relatively common general industrial aluminum powder for calculation. (Note: 1 MPa·m / s = 10 bar·m / s).

[0112] Table 1. Kst values ​​of some aluminum powders under specific laboratory conditions.

[0113]

[0114] In this embodiment, when When the pressure reaches MPa / s, the efficient inerting system is activated; otherwise, pressure monitoring and judgment continue.

[0115] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A graded inertia device based on dynamic risk assessment, characterized in that, It includes a continuous inerting system, a dust removal system, and a high-efficiency inerting system. The dust removal system includes a main dust removal pipeline and a dust collector connected to each other. The continuous inerting system includes an inerting dust silo and a feeding device, which is connected to the main dust removal pipeline. The high-efficiency inerting system includes a high-efficiency inerting powder tank, which is connected to the dust collector.

2. The hierarchical inertia device based on dynamic risk assessment according to claim 1, characterized in that, The main dust removal pipeline is connected to multiple dust removal branch pipes, each of which is equipped with a first dust concentration sensor. A second dust concentration sensor is installed at the end of the main dust removal pipeline near the dust collector. One end of the main dust removal pipeline is connected to the feeding equipment through a check valve, and a third dust concentration sensor is installed at the end of the main dust removal pipeline near the check valve. A pressure sensor is installed in the dust collector.

3. The hierarchical inertia device based on dynamic risk assessment according to claim 2, characterized in that, The inerting dust silo is equipped with a stirring motor and a stirring vessel. The feeding equipment includes a screw feeder connected to the bottom of the inerting dust silo. The screw feeder is connected to a Venturi injector, which is connected to a high-pressure blower. The Venturi injector is connected to a check valve through a pipeline.

4. The hierarchical inertia device based on dynamic risk assessment according to claim 3, characterized in that, Multiple high-efficiency inerting powder tanks are provided, each containing high-pressure inert gas and inert dust. The high-efficiency inerting powder tanks are connected to the dust collector via pneumatic valves.

5. A graded inertia device based on dynamic risk assessment according to claim 4, characterized in that, It also includes a main controller, which is electrically connected to the first dust concentration sensor, the second dust concentration sensor, the third dust concentration sensor, the pressure sensor, the stirring motor, and the high-pressure blower.

6. A hierarchical inertia method based on dynamic risk assessment, characterized in that, The graded inertization device based on dynamic risk assessment, as described in claim 5, comprises the following steps: Step 1: The main controller acquires the value from the first dust concentration sensor. , Let i be the dust concentration value of the first dust concentration sensor, according to The average dust concentration in the main dust collection pipeline was calculated. ; （1）； in, The air volume of the main dust removal duct is in m³ / h. Let be the air volume of the i-th dust removal branch pipe, in m³ / h; Set the threshold for graded dust concentration , , They are respectively: （2）； （3）； （4）； Where MEC is the lower explosive limit concentration of dust, in g / m³; When the main controller detects When the continuous inertization system does not start; when At that time, the continuous inerting system starts, and inerting dust is fed into the main dust collection duct. The continuous inerting system performs the first stage of continuous inerting, and the concentration of inerting dust in the first stage is [missing information]. ; （5）； Minimum inert dust concentration, wt% The dust concentration safety factor is greater than 1; when At that time, the continuous inerting system performs secondary continuous inerting, and the inerting dust concentration during the secondary continuous inerting is... ; （6）； when At that time, the continuous inerting system performs three-stage continuous inerting, and the inerting dust concentration during the three-stage continuous inerting is... ; （7）； , and Detected by a third dust concentration sensor; Step 2: The main controller calculates the concentration difference of combustible dust in the main dust collection duct. Specifically: （8）； in, The dust concentration near the dust collector end is detected by the second dust concentration sensor, whereby... for or or ; Set the risk threshold for combustible dust concentration as for: （9）； when At that time, the high-efficiency inerting system is activated to fill the dust collector with high-pressure inert gas and inert dust from at least one high-efficiency inerting powder tank; Step 3: The main controller acquires the pressure sensor values ​​in real time. Set pressure threshold ,when At that time, the efficient inertization system is not activated; when At that time, the rate of pressure increase With the set pressure rise rate threshold In contrast, when When the high-efficiency inerting system is activated, the high-pressure inert gas and inert dust from at least one high-efficiency inerting powder tank are introduced into the dust collector; when At that time, the efficient inertization system is not activated; in, for: （10）； in, This represents the maximum floating pressure during normal operation of the dust collector, in MPa. Safety margin pressure, MPa; （11）； in, The safety factor for the rate of pressure rise is <0.5; For the volume of the dust collector, m 3 ; The dust explosion index is expressed in bar·m / s. It can be obtained by the main controller through the change value of the pressure sensor per unit time.

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