阅读说明：本技术 粉尘层阴燃模拟研究装置及其用途 (Dust layer smoldering simulation research device and application thereof ) 是由 张* 张 霍明甲 王睿 于 2019-04-04 设计创作，主要内容包括：本发明涉及一种粉尘层阴燃模拟研究装置及其用途,主要解决现有技术中缺乏能对涉及粉尘层阴燃的几个主要影响因素进行全面评估的装置的问题。本发明通过采用一种粉尘层阴燃模拟研究装置,包括数字采集控制系统、粉尘层阴燃试验炉、气体采样分析系统、进气控制系统,数字采集控制系统包括电脑、热电偶、电磁阀、阴燃拍摄点,气体采样分析系统包括气体成分分析仪、储气装置,进气控制系统包括鼓风机、风量控制阀、空气湿度控制器；粉尘层阴燃试验炉包括炉体、炉盖、保温层、加热盘、排气口、温度传感器、进气口的技术方案较好地解决了上述问题,可用于粉尘层阴燃模拟研究中。(The invention relates to a simulation research device for smoldering of a dust layer and application thereof, and mainly solves the problem that a device capable of comprehensively evaluating a plurality of main influence factors related to smoldering of the dust layer is lacked in the prior art. The invention adopts a dust layer smoldering simulation research device, which comprises a digital acquisition control system, a dust layer smoldering test furnace, a gas sampling analysis system and an air inlet control system, wherein the digital acquisition control system comprises a computer, a thermocouple, an electromagnetic valve and a smoldering shooting point, the gas sampling analysis system comprises a gas component analyzer and an air storage device, and the air inlet control system comprises an air blower, an air volume control valve and an air humidity controller; the smoldering test furnace for the dust layer comprises a furnace body, a furnace cover, a heat insulation layer, a heating plate, an exhaust port, a temperature sensor and an air inlet, and can be used for the smoldering simulation research of the dust layer.)

1. A simulation research device for smoldering of a dust layer comprises a digital acquisition control system, a smoldering test furnace of the dust layer, a gas sampling analysis system and an air inlet control system, wherein the digital acquisition control system comprises a computer, a thermocouple, an electromagnetic valve and a smoldering shooting point, the gas sampling analysis system comprises a gas component analyzer and an air storage device, and the air inlet control system comprises an air blower, an air volume control valve and an air humidity controller; the smoldering test furnace for the dust layer comprises a furnace body, a furnace cover, a heat preservation layer, a heating plate, an exhaust port, a temperature sensor and an air inlet, wherein the heating plate is arranged on a liftable porous tray, the vertical cylindrical combustion chamber made of refractory materials is covered with a stainless steel protective shell, a rock wool heat preservation layer is arranged on the outer surface of the vertical cylindrical combustion chamber, the furnace cover is sealed with the furnace body, an adjustable exhaust hole is formed in the center and one side of the furnace cover, and the exhaust hole of the side edge is connected with a gas composition analyzer.

2. The device for simulating and researching smoldering in dust layer according to claim 1, characterized in that the gas composition analyzer, the gas storage tank, the smoldering test furnace and the air blower are connected through gas pipelines and are controlled by the electromagnetic valve to be communicated, air is introduced, waste gas is discharged or collected according to a test process in the whole test process, and the gas composition analyzer is used for analyzing the discharged waste gas.

3. The smoldering simulation study device of claim 1, wherein the dust sample used in the test is fed into the smoldering test furnace through an openable furnace cover, and the smoldering test furnace has at least two sets of temperature sensors, one set is used for testing the temperature of the outer edge of the dust layer, and the other set is used for testing the temperature of the center of the dust layer; in the test process, the entering position and the entering speed of air are determined by controlling the lifting of the heating plate tray support and the opening and closing of the top and bottom air valves, and equipment can respectively simulate downwind smoldering and upwind smoldering at different airflow flow rates.

4. The device for simulating and researching smoldering dust layer of claim 1, wherein the air humidity controller is turned on before the test is started, and the test can be performed after the air humidity reaches a set value.

5. The smoldering simulation research device of a dust layer according to claim 1, wherein the digital acquisition control system functions are realized by various temperature sensors, electromagnetic valves, gas flow meters and cameras connected with a computer, the temperature and airflow change conditions of each part in the system are monitored in real time, relevant data are fed back in time, and test parameters are controlled according to a preset program.

6. The smoldering simulation research device of dust layer of claim 1, wherein the heating plate is a porous powered heating plate, which is used as a heat source for smoldering dust layer and is placed on a porous ceramic tray capable of being lifted, and when the ceramic tray is lowered, airflow entering from the bottom is uniformly distributed in the combustion chamber; when the ceramic tray is lifted to be tightly attached to the heating plate, airflow cannot enter from the bottom of the combustion chamber; the heating plate is internally provided with a metal thermal resistor, the heating temperature is controlled within the range of room temperature to 500 ℃, and the precision is 0.1 ℃.

7. The device for simulating and researching smoldering of dust layer of claim 1, wherein a nickel-chromium thermocouple with a diameter not greater than 1mm is used to record smoldering temperature rise courses of dust layers with different thicknesses, and the temperatures of the center and the outer edge of the dust layer are respectively tested.

8. The device for simulating and researching smoldering of dust layer of claim 1, wherein the gas composition analyzer is disposed on top of the smoldering test furnace of the dust layer, and the detecting comprises O₂、N₂、CO、CO₂、SO₂The concentration of (c).

9. The smoldering simulation study device of dust layer of claim 1, wherein the air blower continuously blows air into the smoldering test furnace through the air inlet hole, and the air flow speed can be controlled by the control valve; the air humidity controller mainly comprises a sensor, a controller and a heater, is placed in a fume hood for equipment work and is used for controlling the humidity of gas entering the smoldering furnace; the smoldering shooting point is that a camera is connected on the computer, and when the dust sample to be measured smolders, the test phenomenon can be obviously observed.

10. A simulation study device for smoldering of dust layer as claimed in claims 1-9, used in the simulation study of smoldering of dust layer.

Technical Field

The patent relates to a study device is fired in shade in dust layer belongs to industry dust explosion protection technical field, and mainly used evaluates the smoldering danger of various industry dust in production and storage, can comprehensively record the change condition of temperature, humidity, air current, combustion products in whole dust layer smoldering process.

Background

With the development of modern industry, the variety of dust is continuously enlarged, the use amount is continuously increased, and the potential danger of dust explosion is greatly increased. According to statistics, dust explosion accidents happen on average every day in the world. The smoldering combustion of dust is a slow oxidative exothermic reaction of combustible dust under certain conditions, and is an important factor for inducing dust explosion accidents.

How to test the smoldering temperature of the dust layer with a specific thickness is specified in two standards of GB/T16430-1996 method for measuring the minimum ignition temperature of the dust layer and VDI 2263. However, there is no device for comprehensively evaluating several main influence factors related to smoldering of the dust layer, and the smoldering risk of the dust layer cannot be conveniently researched.

Disclosure of Invention

One of the technical problems to be solved by the invention is the problem that the prior art lacks a device capable of comprehensively evaluating a plurality of main influence factors related to smoldering of a dust layer, and the invention provides a novel simulation and research device for smoldering of the dust layer, which has the advantage of the device capable of comprehensively evaluating the plurality of main influence factors related to smoldering of the dust layer. The invention also provides the application of the simulation research device for the smoldering of the dust layer corresponding to the technical problem to be solved.

In order to solve one of the problems, the technical scheme adopted by the invention is as follows: a simulation research device for smoldering of a dust layer comprises a digital acquisition control system, a smoldering test furnace of the dust layer, a gas sampling analysis system and an air inlet control system, wherein the digital acquisition control system comprises a computer, a thermocouple, an electromagnetic valve and a smoldering shooting point; the smoldering test furnace for the dust layer comprises a furnace body, a furnace cover, a heat preservation layer, a heating plate, an exhaust port, a temperature sensor and an air inlet, wherein the heating plate is arranged on a lifting porous tray, the vertical cylindrical combustion chamber made of refractory materials is covered with a stainless steel protective shell, the inner lining rock wool heat preservation layer is covered on the vertical cylindrical combustion chamber, the furnace cover is sealed with the furnace body, an adjustable exhaust hole is formed in the center and one side of the furnace cover, and the exhaust hole of the side edge is connected with a gas composition analyzer.

Among the above-mentioned technical scheme, preferably, gas composition analysis appearance, gas holder, smoldering test stove, air-blower pass through the gas circuit pipeline and link to each other, are put through by solenoid valve control, and air, discharge or collection waste gas are let in according to the test process in whole testing process, use gas composition analysis appearance to carry out the analysis to exhaust waste gas.

In the technical scheme, preferably, a dust sample used for the test is added into a dust layer smoldering test furnace through an openable furnace cover, the dust layer smoldering test furnace is provided with at least two groups of temperature sensors, one group is used for testing the temperature of the outer edge of the dust layer, and the other group is used for testing the temperature of the center of the dust layer; in the test process, the entering position and the entering speed of air are determined by controlling the lifting of the heating plate tray support and the opening and closing of the top and bottom air valves, and equipment can respectively simulate downwind smoldering and upwind smoldering at different airflow velocities.

In the above technical solution, preferably, before the test starts, the air humidity controller needs to be opened first, and the test can be performed after the air humidity reaches the set value.

In the above technical scheme, preferably, the digital acquisition control system is implemented by each temperature sensor, the electromagnetic valve, the gas flowmeter and the camera which are connected with the computer, the temperature and the gas flow change condition of each part in the system are monitored in real time, relevant data are fed back in time, and the test parameters are controlled according to a preset program.

In the above technical solution, preferably, the heating plate is a porous powered heating plate, which is used as a heat source for smoldering dust layer and is placed on a porous ceramic tray capable of being lifted, and when the ceramic tray is lowered, airflow entering from the bottom is uniformly distributed in the combustion chamber; when the ceramic tray is lifted to be tightly attached to the heating plate, airflow cannot enter from the bottom of the combustion chamber; the heating plate is internally provided with a metal thermal resistor, the heating temperature is controlled within the range of room temperature to 500 ℃, and the precision is 0.1 ℃.

In the technical scheme, preferably, a nickel-chromium thermocouple with the diameter not more than 1mm is used for recording smoldering temperature rise processes of dust layers with different thicknesses, and the temperatures of the center and the outer edge of the dust layer are respectively tested.

In the above technical solution, preferably, the gas composition analyzer is disposed at the top of the smoldering test furnace of the dust layer, and the detecting includes O₂、N₂、CO、CO₂、SO₂The concentration of (c).

In the technical scheme, preferably, the air blower continuously introduces air into the smoldering test furnace through the air inlet hole, and the air flow speed can be controlled through the control valve; the air humidity controller mainly comprises a sensor, a controller and a heater, is placed in a fume hood for equipment work and is used for controlling the humidity of gas entering the smoldering furnace; the smoldering shooting point is that a camera is connected to a computer, and when the dust sample to be tested is smoldered, the test phenomenon can be obviously observed.

In order to solve the second problem, the invention adopts the following technical scheme: the utility model provides a dust layer smoldering simulation research device's use, is arranged in the dust layer smoldering simulation research.

This patent is a set of test device that is used for studying the dust blanket smoldering process specially, and dust blanket smoldering test device in the past can only test this parameter of dust blanket smoldering temperature of specific thickness. And the test device that this patent designed can comprehensively record the dust layer of analysis different thickness and burn the situation of change of in-process temperature, humidity, air current, combustion products in the smoldering, and the dust smoldering under the real environment of simulation not only can carry out effectual research to each factor that influences the dust layer smoldering effectively, and the operation of just being convenient for still, very big development that has made things convenient for relevant scientific research work has made better technological effect.

Drawings

FIG. 1 is a schematic view of a smoldering test furnace for a dust layer according to the present invention.

In FIG. 1, 1. a central exhaust port of a furnace cover; 2. an exhaust port is formed in the side edge of the furnace cover; 3. a furnace cover; 4. a top air intake valve; 5. a heat-insulating layer; 6. a central temperature sensor; 7. an edge temperature sensor; 8. a bottom air intake valve; 9. a heating disc and a bracket; 10. metal filter screens and grates; 11. an air inlet; 12. a camera is provided.

The present invention will be further illustrated by the following examples, but is not limited to these examples.

Detailed Description

[ example 1 ]

A simulation research device for smoldering of a dust layer is composed of a digital acquisition control system, a smoldering test furnace of the dust layer, a gas sampling analysis system and an air inlet control system.

1. The system comprises the following components:

the digital acquisition control system comprises: computer, thermocouple, electromagnetic valve, smoldering shooting point, etc.

Dust blanket smoldering test furnace: furnace body, furnace cover, heat-insulating interlayer, porous electric heating plate and the like

Gas sampling analysis system: gas component analyzer, gas storage device, and the like

An air intake control system: a blower, an air volume control valve, an air humidity controller and the like.

2. The connection relation of each component is as follows:

the gas component analyzer, the gas storage tank, the smoldering test furnace and the air blower are connected through steel gas path pipes and are controlled to be communicated by an electromagnetic valve. And introducing air, discharging or collecting waste gas according to the test process in the whole test process. The discharged exhaust gas was analyzed using a gas composition analyzer.

The dust sample used for the test was introduced into the smoldering test furnace through an openable furnace lid. The test furnace is provided with two groups of temperature sensors, one group is used for testing the temperature of the outer edge of the dust layer, and the other group is used for testing the temperature of the center of the dust layer. In the testing process, the entering position and speed of air can be determined by controlling the lifting of the heating plate tray support and the opening and closing of the top and bottom air valves, and the device can respectively simulate downwind smoldering and upwind smoldering at different airflow velocities.

Before the test is started, the air humidity controller needs to be opened, and the test can be carried out after the air humidity reaches a set value.

The digital acquisition control system is realized by various temperature sensors, electromagnetic valves, gas flow meters, cameras and the like which are directly connected with a computer, monitors the temperature and airflow change conditions of each part in the system in real time, feeds back related data in time and controls test parameters according to a preset program.

Introduction of main instruments and equipment of a dust layer smoldering test furnace (shown in figure 1):

1. porous electric heating plate: as a heat source for smoldering dust layers, the diameter of the dust layer is 10cm, and the dust layer is arranged on a porous ceramic tray which can be lifted. When the ceramic tray is lowered, airflow entering from the bottom can be uniformly distributed in the combustion chamber; when the ceramic tray is raised against the heater plate, airflow cannot enter from the bottom of the combustion chamber. The heating plate is internally provided with a metal thermal resistor, the heating temperature can be controlled within the range of room temperature to 500 ℃, and the precision is 0.1 ℃.

2. A temperature sensing device: 40 nickel-chromium thermocouples, no larger than 1mm in diameter, were used to record the smoldering temperature rise history for dust layers of different thicknesses. The 40 thermocouples were divided into 20 groups of 2 each and the temperature of the center and outer edge of the dust layer was measured respectively.

3. Gas composition analyzer: placed at the top of the combustion chamber and can detect O₂、N₂、CO、CO₂、SO₂And the gas concentration is equal. Smoldering furnace body: the vertical cylindrical combustion chamber made of refractory material is covered with a stainless steel protective shell and lined with rock wool heat-insulating material. The furnace body height of the smoldering furnace is 18cm, and the diameter is 15 cm. The furnace cover has good sealing performance with the furnace body, the upper center and one side of the furnace cover are provided with adjustable exhaust holes, and the exhaust holes at the side edges can be connected with a gas component analyzer

4. A blower: air can be continuously introduced into the smoldering furnace through the air inlet hole, and the air flow speed can be controlled through the control valve. The experimental wind speed can be controlled at 0.3 m/s.

5. An air humidity controller: the device mainly comprises a sensor, a controller and a heater. Is arranged in a fume hood for equipment work and is used for controlling the humidity of gas entering the smoldering furnace.

6. Smoldering shooting point: namely, a camera is connected to a computer, and when the dust sample to be tested is smoldered, the test phenomenon can be obviously observed.

When the device is used, the test needs to be carried out in a fume hood, an exhaust system is suitable for absorbing toxic smoke, an experimenter needs to wear an explosion-proof helmet, goggles and protective gloves before operation, and then the test is carried out according to the following steps:

1. connecting all parts of the device, opening control software, and presetting parameters such as heating temperature, dust layer thickness, sample quality, airflow direction, airflow flow, airflow humidity and the like.

2. The test furnace cover is opened, and a proper amount of dust sample is added according to the set sample parameters (the height of the added dust sample is not less than 5mm and not more than 100mm, and the diameter of the dust layer is 100 mm).

3. The testing device is started, and the heating furnace disc starts to heat the sample dust.

4. The dust sample temperature was observed at each recording point as a function of time. Smoldering (or self-heating) of the dust was observed and recorded.

5. And opening the gas collecting and analyzing device after the smoldering of the dust layer occurs, and analyzing the components of the collected gas.

6. And (4) readjusting various parameters according to research needs, and repeating the operation steps until a satisfactory test result is obtained.

[ example 2 ]

The device is used for the smoldering simulation of a wheat dust layer with the median particle size of 100um according to the conditions and the steps described in the example 1, and characteristic gases generated after burning are researched and analyzed, and the device comprises the following steps:

1. connecting all parts of the device, opening control software, presetting the heating temperature to be 300 ℃, the dust layer thickness to be 60mm, the sample quality, the airflow direction to be positive, and the airflow velocity to be 15 cm/min.

2. And opening the test furnace cover, and adding a proper amount of wheat dust samples to the 60mm scale mark of the test furnace according to the set sample parameters.

3. The testing device is started, and the heating furnace disc starts to heat the sample dust.

4. The dust sample temperature was observed at each recording point as a function of time. The smoldering condition of the dust was checked and recorded.

5. When the smoldering of the dust layer occurs (when the maximum temperature of the temperature recording point of each dust layer exceeds the heating temperature by 200 ℃, the dust layer is considered to start to smolder), the gas collection and analysis device is opened, and the collected gas is subjected to component analysis.

6. The flow rate of the gas stream was adjusted to 30cm/min as required for the study, the other parameters were unchanged, the above procedure was repeated and the results recorded as shown in table 1.

TABLE 1 characteristic gas composition of wheat dust samples smoldering for 60min at different gas flow rates

Wind speed	N2/％	O2/％	CO2/％	CO/％	CH4/％
						15cm/min	70.1	2.2	19.1	3.0	0.2
30cm/min	70.8	5.8	16.2	3.7	0.4

[ example 3 ]

The apparatus was used for smoldering simulation of 75um median particle size stone pine nut dust blanket, following the conditions and procedures described in example 1, and the temperature variation at different thicknesses of the dust blanket was studied throughout the process, including the following steps:

1. connecting all parts of the device, opening control software, presetting the heating temperature to be 300 ℃, the dust layer thickness to be 60mm, the sample quality, the airflow direction to be positive, and the airflow velocity to be 15 cm/min.

2. And opening the test furnace cover, and adding a proper amount of wheat dust samples to the 60mm scale mark of the test furnace according to the set sample parameters.

3. The testing device is started, and the heating furnace disc starts to heat the sample dust.

4. The dust sample temperature was observed at each recording point as a function of time. The smoldering condition of the dust was checked and recorded.

5. Smoldering occurs when the dust layer (smoldering is considered to begin when the maximum temperature of the temperature recording point of each dust layer exceeds the heating temperature by 200 ℃). The time-dependent temperature profile of the dust sample at each recorded point was obtained and analyzed.

[ COMPARATIVE EXAMPLE ]

The mainstream smoldering test device for the dust layer in the market is only simple and used for meeting the test requirements of two standards of GB/T16430 and 1996, namely, a method for measuring the minimum ignition temperature of the dust layer and VDI 2263, and can only be used for measuring whether smoldering occurs in the dust at a specific temperature and thickness. The invention is far less comprehensive and detailed than the analysis provided by the invention. The change conditions of temperature, humidity, airflow and combustion products in the whole smoldering process of the dust layer can be comprehensively recorded.