An organic gas explosion-proof safety detection system and a method of using the same

Abstract

The application discloses an organic gas explosion-proof safety detection system and a use method thereof. The system comprises an air inlet pipeline, a pre-combustion unit, a three-way valve, a waste gas purification unit and an emergency treatment unit. The emergency treatment unit comprises an emergency discharge pipeline. The air inlet pipeline is connected with the inlet of the three-way valve. The first outlet of the three-way valve is connected with the waste gas purification unit. The second outlet of the three-way valve is connected with the emergency discharge pipeline. The pre-combustion system comprises a pre-combustion air inlet pipeline, a sampling pump and a pre-combustion chamber. The pre-combustion chamber is a heatable pressure container. The air inlet of the pre-combustion chamber is communicated with the air inlet pipeline through the pre-combustion air inlet pipeline. According to the waste gas flow direction, the communication position of the pre-combustion air inlet pipeline and the air inlet pipeline is located in front of the three-way valve. The sampling pump is arranged on the pre-combustion air inlet pipeline. The application has the advantages of fast response speed, low system energy consumption and intrinsic safety.

Description

Technical Field

[0001] This invention belongs to the field of waste gas treatment, and relates to a waste gas purification system, and more particularly to an organic gas explosion-proof safety detection system and its usage method. Background Technology

[0002] VOCs as PM 2.5 As a key precursor to O3, VOCs have become a significant constraint on improving air quality. Statistics show that in key industries such as pharmaceuticals and petrochemicals, accidents caused by the combustion and explosion of organic gases account for over 40% of all accidents. The safety of VOCs treatment has become a major issue restricting the development of related industries; explosions of organic waste gas treatment devices occur frequently, and existing explosion-proof safety detection systems are insufficient to guarantee completely safe operation.

[0003] Regenerative thermal combustion and regenerative catalytic combustion are among the most widely used and effective technologies in VOCs treatment. However, due to the high-temperature combustion involved, safety remains a significant challenge in VOCs treatment. The conventional approach is to ensure the peak inlet concentration is below 25% LEL (Less than 25% of the total energy consumption level). Currently, the most common method is to use instruments such as PID (Polymer Detection), FID (Fixed Intake), FAT (Fixed Atmosphere Test), and LEL to monitor the inlet concentration of exhaust gas. When the exhaust gas concentration is too high, dilution and buffering measures are used to prevent combustion and explosion accidents. The accuracy and stability of VOCs concentration detection are crucial. However, VOCs exhaust gases are complex, especially in industries such as pharmaceuticals and chemicals, where VOCs components are complex and concentrations fluctuate significantly. Instruments based on a single detection principle show large differences in response factors for different substances, leading to misjudgments due to instruments not responding to some substances or responding too highly to others. Conversely, if the detected concentration is higher than the actual concentration, excessive dilution will result in an excessively low exhaust gas concentration, causing the combustion device to be unable to maintain self-heating combustion, requiring the addition of large amounts of fossil fuels such as natural gas, resulting in high energy consumption. If the detected concentration is lower than the actual concentration, system safety cannot be guaranteed.

[0004] The fundamental cause of an explosion in an exhaust gas combustion device is that the concentration of VOCs is too high (when it reaches the lower explosive limit). When VOCs decompose in the combustion chamber, they release a large amount of heat, causing the system temperature and pressure to rise sharply, which in turn leads to an explosion. Summary of the Invention

[0005] This invention provides an organic gas explosion-proof safety detection system and its usage method to overcome the defects of the prior art.

[0006] To achieve the above objectives, the present invention provides an organic gas explosion-proof safety detection system, characterized by comprising an inlet pipeline, a pre-combustion unit, a three-way valve, an exhaust gas purification unit, and an emergency treatment unit; the emergency treatment unit includes an emergency discharge pipeline; the inlet pipeline is connected to the inlet of the three-way valve, the first outlet of the three-way valve is connected to the exhaust gas purification unit, and the second outlet of the three-way valve is connected to the emergency discharge pipeline; the pre-combustion system includes a pre-combustion inlet pipeline, a sampling pump, and a pre-combustion chamber; the pre-combustion chamber is a heatable pressure vessel; the inlet of the pre-combustion chamber is connected to the inlet pipeline through the pre-combustion inlet pipeline, and the connection point between the pre-combustion inlet pipeline and the inlet pipeline is located before the three-way valve according to the exhaust gas flow direction; the sampling pump is installed on the pre-combustion inlet pipeline.

[0007] Furthermore, the present invention provides an organic gas explosion-proof safety detection system, which may also have the following feature: wherein the pre-combustion chamber is equipped with a pressure sensor and a temperature sensor.

[0008] Furthermore, the present invention provides an organic gas explosion-proof safety detection system, which may also have the following features: wherein the pre-combustion system further includes an intake one-way valve, a pre-combustion unit flame arrester, and a mass flow meter disposed on the pre-combustion intake pipeline.

[0009] Furthermore, the present invention provides an organic gas explosion-proof safety detection system, which may also have the following features: wherein the pre-combustion chamber includes, from the outside to the inside, an outer casing, an insulation layer and an inner casing, and an electric heater is provided between the insulation layer and the inner casing; the pre-combustion system also includes a pre-combustion exhaust pipe connected to the gas outlet of the pre-combustion chamber, and an exhaust one-way valve is provided on the pre-combustion exhaust pipe;

[0010] The pre-combustion chamber is equipped with a safety valve and a rupture disc; when the pressure exceeds 1 / 4, 1 / 3 or 1 / 2 (preferably 1 / 2) of the maximum pressure that the inner chamber can withstand, the safety valve opens to release pressure, and the sampling pump and the air inlet check valve are closed at the same time; when the pressure exceeds 2 / 3 of the pressure in the inner chamber, the rupture disc bursts to release pressure.

[0011] Furthermore, the present invention provides an organic gas explosion-proof safety detection system, which may also have the following feature: wherein the emergency treatment unit further includes an emergency fan installed on the emergency discharge pipeline.

[0012] Furthermore, the present invention provides an organic gas explosion-proof safety detection system, which may also have the following features: wherein the exhaust gas purification unit includes a purification pipeline, an exhaust gas treatment device, and a purification exhaust pipeline; the air inlet of the exhaust gas treatment device is connected to the first outlet of a three-way valve through the purification pipeline; the air outlet of the exhaust gas treatment device is connected to an emergency discharge pipeline through the purification exhaust pipeline; the exhaust gas treatment device is an RTO device or an RCO device; when the exhaust gas treatment device is an RTO device, the temperature in the pre-combustion chamber is controlled at 760~850℃; when the exhaust gas treatment device is an RCO device, the temperature in the pre-combustion chamber is controlled at 300~450℃.

[0013] Furthermore, the present invention provides an organic gas explosion-proof safety detection system, which may also have the following features: wherein the exhaust gas purification unit further includes a main fan and a purification unit flame arrester installed on the purification pipeline.

[0014] Furthermore, the present invention provides an organic gas explosion-proof safety detection system, which may also have the following features: it further includes a pre-processor disposed on the intake pipe, and the pre-processor is located before the pre-combustion intake pipe according to the direction of exhaust gas flow.

[0015] This invention also provides a method for using an organic gas explosion-proof safety detection system, characterized by the following: exhaust gas enters the system through an inlet pipe, passes through a three-way valve, and enters an exhaust gas purification unit for treatment; before the exhaust gas enters the exhaust gas purification unit for treatment, a sampling pump extracts a fixed flow rate of air from the exhaust gas and enters the pre-combustion chamber for combustion; when the temperature and pressure in the pre-combustion chamber change drastically (pressure increase rate exceeds 1~10 MPa / s), the three-way valve is switched in an emergency, and the exhaust gas is safely discharged through an emergency discharge pipe.

[0016] Pressure and temperature sensors are interlocked with the three-way valve, sampling pump, and inlet check valve for control. The sampling, reaction, and interlock control response time is 1-3 seconds. The pipeline length from the pre-combustion unit to the three-way valve is sufficient to ensure that exhaust gases with combustion and explosion risks are switched to the emergency treatment unit before entering the exhaust gas purification unit.

[0017] Furthermore, the present invention provides a method for using an organic gas explosion-proof safety detection system, which may also have the following features: when the composition of the exhaust gas is determined, the pressure change of exhaust gas of different concentrations entering the pre-combustion chamber is obtained through experiments, and the pressure value lower than that before the pressure change is directly set as the emergency discharge pressure. When the pressure of the exhaust gas in the pre-combustion chamber reaches the emergency discharge pressure, the three-way valve is switched in an emergency to allow the exhaust gas to be safely discharged through the emergency discharge pipeline.

[0018] The beneficial effects of this invention are as follows: This invention provides an organic gas explosion-proof safety detection system and its usage method, which determines the risk of VOCs explosion by monitoring changes in temperature and pressure during the VOCs combustion process. Specifically, this invention extracts a small amount of waste gas for pre-combustion, and by monitoring changes in temperature and pressure in the pre-combustion chamber, it can accurately predict whether there is a risk of combustion and explosion in the waste gas treatment equipment (RTO equipment or RCO equipment), possessing inherent safety characteristics and fundamentally avoiding the risk of combustion and explosion due to low concentration monitoring. It also solves the problem of energy waste caused by excessively high detection concentrations.

[0019] This invention replaces online exhaust gas concentration monitoring instruments with a pre-combustion unit, which can accurately predict whether the exhaust gas entering the exhaust gas treatment equipment (RTO or RCO equipment) poses an explosion risk. It also avoids the energy waste caused by the difference in response factors of online monitoring instruments to different pollutant components, leading to measured concentrations far exceeding actual concentrations. In existing technologies, concentration detection instruments often use the 25% lower explosive limit (LEL) as the concentration control point to ensure system safety. However, this system can operate above 25% LEL but below the LEL, meaning that when the exhaust gas concentration is above 25% but below the LEL with no risk of combustion or explosion, the system can be kept safe without offset dilution, further reducing the energy waste caused by reducing exhaust gas concentration through offset dilution.

[0020] The pre-combustion chamber is a pressure vessel equipped with a safety valve and a rupture disc to cope with multiple combustion and explosion of pre-combustion gases. The inlet check valve and the pre-combustion unit flame arrester can completely isolate the pre-combustion chamber from the exhaust gas inlet pipeline to prevent the impact of the combusted exhaust gas on the main system.

[0021] This invention features fast response speed, low system energy consumption, and intrinsic safety. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an organic gas explosion-proof safety detection system;

[0023] Figure 2 It is a graph showing the pressure / temperature of the exhaust gas in the pre-combustion chamber as a function of concentration. Detailed Implementation

[0024] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, the present invention provides an organic gas explosion-proof safety detection system, including an air inlet pipe 1, a pre-combustion unit, a three-way valve 3, an exhaust gas purification unit, and an emergency treatment unit.

[0026] The intake pipe 1 is connected to the inlet of the three-way valve 3, the first outlet of the three-way valve 3 is connected to the exhaust gas purification unit, and the second outlet of the three-way valve 3 is connected to the emergency treatment unit.

[0027] The exhaust gas purification unit includes a purification pipeline 41, an exhaust gas treatment device 42, and a purified exhaust pipeline 43. The inlet of the exhaust gas treatment device 42 is connected to the first outlet of the three-way valve 3 via the purification pipeline 41. The outlet of the exhaust gas treatment device 42 is connected to the emergency discharge pipeline 51 via the purified exhaust pipeline 43. The exhaust gas treatment device 42 is either an RTO (Regenerative Thermal Oxidizer) device or an RCO (Regenerative Control Unit).

[0028] In a preferred embodiment, the exhaust gas purification unit further includes a main fan 44 and a purification unit flame arrester 45 disposed on the purification pipeline 41.

[0029] The emergency response unit includes an emergency discharge pipeline 51 connected to the second outlet of the three-way valve 3, and an emergency fan 52 installed on the emergency discharge pipeline 51.

[0030] The pre-combustion system includes a pre-combustion inlet pipe 21, a sampling pump 22, and a pre-combustion chamber 23. The pre-combustion chamber 23 is a heatable pressure vessel, comprising an outer casing, an insulation layer, and an inner casing from the outside in. An electric heater is installed between the insulation layer and the inner casing. The inlet of the pre-combustion chamber 23 is connected to the intake pipe 1 via the pre-combustion inlet pipe 21. Following the exhaust gas flow direction, the connection point between the pre-combustion inlet pipe 21 and the intake pipe 1 is located before the three-way valve 3. The sampling pump 22 is mounted on the pre-combustion inlet pipe 21.

[0031] The pre-combustion system also includes a pre-combustion exhaust pipe 28 connected to the exhaust port of the pre-combustion chamber 23, and the pre-combustion exhaust pipe 28 is equipped with an exhaust check valve.

[0032] The pre-combustion chamber 23 is equipped with a pressure sensor 24 and a temperature sensor 25 to detect the pressure and temperature inside the pre-combustion chamber 23.

[0033] When the exhaust gas treatment equipment 42 is an RTO (Regenerative Thermal Oxidizer) device, the temperature inside the pre-combustion chamber 23 is controlled at 760~850℃. When the exhaust gas treatment equipment 42 is an RCO (Regenerative Combustion Organism) device, the temperature inside the pre-combustion chamber 23 is controlled at 300~450℃.

[0034] In a preferred embodiment, the pre-combustion system further includes an intake check valve 26 and a pre-combustion unit flame arrester 27 disposed on the pre-combustion intake pipe 21. The pre-combustion chamber 23 is equipped with a safety valve and a rupture disc. When the pressure exceeds 1 / 4, 1 / 3, or 1 / 2 (preferably 1 / 2) of the maximum pressure that the inner chamber can withstand, the safety valve opens to release pressure, while the sampling pump 22 and the intake check valve 26 are closed to prevent the exhaust gas from exploding in the pre-combustion chamber 23 and impacting the exhaust gas purification unit. When the pressure exceeds 2 / 3 of the pressure in the inner chamber, the rupture disc bursts to release pressure, enabling rapid pressure relief and further improving system safety.

[0035] In a preferred embodiment, the pre-combustion system further includes a mass flow meter disposed on the pre-combustion intake line 21 to detect the sampled flow rate 29.

[0036] The system also includes a pre-processor 6 installed on the intake pipe 1, which is located before the pre-combustion intake pipe 21 according to the exhaust gas flow direction. The pre-processor 6 performs pre-combustion treatment on the exhaust gas, such as filtration.

[0037] The operating method of the organic gas explosion-proof safety detection system is as follows: Exhaust gas enters the system through inlet pipe 1, passes through three-way valve 3, and then enters the exhaust gas purification unit for treatment. Before the exhaust gas enters the purification unit, sampling pump 22 extracts a fixed flow rate of gas from the exhaust gas, controls the gas volume through a mass flow meter, and then allows combustion to occur inside the pre-combustion chamber 23. During combustion within the pre-combustion chamber 23, the temperature and pressure inside the chamber change, with the magnitude of these changes depending on the properties and concentration of the combustible components in the exhaust gas. Specifically, when the exhaust gas concentration is below the explosion limit, the temperature and pressure change little with the exhaust gas concentration; however, when the lower explosion limit is reached, the temperature and pressure change drastically. Figure 2 As shown, the concentration of combustible gas in the exhaust gas at point A is 0, and point C is close to the lower explosive limit of the combustible gas. When the exhaust gas concentration is between points A and C at point B, the exhaust gas purification system is in a relatively safe state. When the exhaust gas concentration is at point D, it is higher than the explosive limit, and the exhaust gas purification system has a risk of combustion and explosion. When the temperature and pressure in the pre-combustion chamber 23 change drastically (the pressure increase rate exceeds 1~10 MPa / s), the emergency switching three-way valve 3 is activated, and the exhaust gas is safely discharged through the emergency discharge pipeline 51.

[0038] Pressure sensor 24 and temperature sensor 25 are interlocked with three-way valve 3, sampling pump 22 and inlet one-way valve 26 for control. The sampling, reaction and interlock control response time is 1~3 s. The pipeline length from the pre-combustion unit to the three-way valve 3 is sufficient to ensure that the exhaust gas with the risk of combustion and explosion is switched to the emergency treatment unit before entering the exhaust gas purification unit.

[0039] When the exhaust gas composition is determined, the pressure changes of exhaust gas with different concentrations entering the pre-combustion chamber 23 are obtained through experiments. The pressure value below the level before the rapid pressure change (i.e., point C) is directly set as the emergency discharge pressure. When the pressure of the exhaust gas in the pre-combustion chamber 23 reaches the emergency discharge pressure, the three-way valve 3 is switched on in an emergency, allowing the exhaust gas to be safely discharged through the emergency discharge pipeline 51. This method of determining the composition can reduce the combustion and explosion reactions of the exhaust gas in the pre-combustion chamber 23 and increase the service life of the pre-combustion chamber 23.

Claims

1. A method for detecting the explosion-proof safety of organic gases, characterized in that: Implemented through an organic gas explosion-proof safety detection system; The system includes an intake duct, a pre-combustion unit, a three-way valve, an exhaust gas purification unit, and an emergency treatment unit; The emergency response unit includes emergency discharge piping; The intake pipe is connected to the inlet of the three-way valve, the first outlet of the three-way valve is connected to the exhaust gas purification unit, and the second outlet of the three-way valve is connected to the emergency discharge pipe. The pre-combustion unit includes a pre-combustion intake pipe, a sampling pump, and a pre-combustion chamber; The pre-combustion chamber is a heatable pressure vessel; the air inlet of the pre-combustion chamber is connected to the air intake pipe through the pre-combustion air intake pipe, and the connection point between the pre-combustion air intake pipe and the air intake pipe is located before the three-way valve according to the direction of exhaust gas flow. The sampling pump is installed on the pre-combustion intake pipe; The pre-combustion chamber is equipped with pressure and temperature sensors; The method is as follows: exhaust gas enters the system through the intake pipe, passes through the three-way valve and enters the exhaust gas purification unit for treatment; before the exhaust gas enters the exhaust gas purification unit for treatment, the sampling pump extracts a fixed flow rate of air from the exhaust gas and enters the pre-combustion chamber for combustion; when the temperature and pressure in the pre-combustion chamber change drastically, the three-way valve is switched in an emergency, and the exhaust gas is safely discharged through the emergency discharge pipe.

2. The method for detecting explosion-proof safety of organic gases according to claim 1, characterized in that: in, The pre-combustion unit also includes an intake check valve, a pre-combustion unit flame arrester, and a mass flow meter installed on the pre-combustion intake pipe.

3. The method for detecting explosion-proof safety of organic gases according to claim 2, characterized in that: in, The pre-combustion chamber comprises, from the outside to the inside, an outer casing, an insulation layer, and an inner casing, with an electric heater installed between the insulation layer and the inner casing. The pre-combustion unit also includes a pre-combustion exhaust pipe connected to the exhaust port of the pre-combustion chamber, and the pre-combustion exhaust pipe is equipped with an exhaust check valve; The pre-combustion chamber is equipped with a safety valve and a rupture disc; When the pressure exceeds 1 / 4, 1 / 3 or 1 / 2 of the maximum pressure that the inner chamber can withstand, open the safety valve to release the pressure, and at the same time close the sampling pump and the air inlet check valve. When the pressure exceeds 2 / 3 of the pressure inside the chamber, the rupture disc bursts and releases pressure.

4. The method for detecting the explosion-proof safety of organic gases according to claim 1, characterized in that: in, The emergency response unit also includes an emergency fan installed on the emergency discharge pipeline.

5. The method for detecting explosion-proof safety of organic gases according to claim 1, characterized in that: in, The exhaust gas purification unit includes purification pipelines, exhaust gas treatment equipment, and purified exhaust pipelines; The air inlet of the exhaust gas treatment equipment is connected to the first outlet of the three-way valve through a purification pipeline; the air outlet of the exhaust gas treatment equipment is connected to the emergency discharge pipeline through a purification exhaust pipeline. The waste gas treatment equipment is either an RTO (Regenerative Thermal Oxidizer) or an RCO (Regenerative Control Unit). When the exhaust gas treatment equipment is an RTO equipment, the temperature in the pre-combustion chamber is controlled at 760~850℃; When the exhaust gas treatment equipment is an RCO equipment, the temperature in the pre-combustion chamber is controlled at 300~450℃.

6. The method for detecting the explosion-proof safety of organic gases according to claim 5, characterized in that: in, The exhaust gas purification unit also includes a main fan installed on the purification pipeline and a purification unit flame arrester.

7. The method for detecting the explosion-proof safety of organic gases according to claim 1, characterized in that: It also includes a pre-processor installed on the intake pipe, which is located before the pre-combustion intake pipe according to the direction of exhaust flow.

8. The method for detecting explosion-proof safety of organic gases according to claim 1, characterized in that: in, When the composition of the exhaust gas is determined, the pressure change of exhaust gas with different concentrations entering the pre-combustion chamber is obtained through experiments. The pressure value below the pressure before the rapid pressure change is directly set as the emergency discharge pressure. When the pressure of the exhaust gas in the pre-combustion chamber reaches the emergency discharge pressure, the three-way valve is switched in an emergency to allow the exhaust gas to be safely discharged through the emergency discharge pipeline.

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