Comprehensive solution for coalfield safety monitoring system

1.The need for environmental monitoring of closed coal sites

In coal mines, thermal power plants, cogeneration plants and other places where coal needs to be stored and turned around, coal in long-term contact with air will undergo oxidation reactions and release heat. Although the heat in the outer layer of the coal pile can be distributed, due to the slow air flow and poor ventilation inside the pile, resulting in the accumulation of internal heat, the temperature inside the pile becomes higher and higher, and when the temperature exceeds the spontaneous combustion point of coal, spontaneous combustion will occur, causing great damage to personnel and equipment. At the same time, along with the spontaneous combustion of coal will also produce carbon monoxide, methane and other toxic and harmful gases, in the current form of national vigorous implementation of environmental management, real-time effective monitoring of coal pile temperature has huge social and economic benefits, is an important part of the implementation of the "electronic coal yard", has a great need.

2.Existing ways of monitoring coal pile temperature

1）Manual inspection: The manual handheld thermometer patrol is used. Disadvantages: 24-hour real-time monitoring cannot be implemented, and the effective measurement density cannot be achieved. Due to the harsh environment of the site and the large equipment, the safety of the inspectors is also affected.

2）Use infrared thermal imager with 360° head rotation to collect temperature changes on the surface of the coal pile and monitor a wide range.

3）Plug-in pyrometer, plug-in pyrometer probe rod length 2 meters, built-in 3 temperature measurement points, through the wireless way to monitor the temperature data transmitted to the host and the host computer, to achieve 24-hour real-time monitoring. If the site operation equipment or harsh environment can choose 485 wired transmission method, detect the temperature between the coal and the wall, and equipment attached to the coal retaining wall can be.

3.Monitoring methods for combustible gases in closed coal yards

Coal dust and gas explosion caused by the material is often mixed in the air in suspension, the explosion occurs instantaneously, so it is very important for the prevention of this disaster in advance. In addition, for the working yard, water dust removal device should be used to reduce the dust concentration at the drop point, and set up a dust concentration detector to monitor the concentration of dust in the coal yard. In the early stage of spontaneous combustion, carbon monoxide will be produced due to low temperature oxidation, and the concentration of oxygen also changes, so it is necessary to set up carbon monoxide and oxygen detection devices for real-time monitoring, so that early detection and timely measures can be taken. In order to ensure the safety of the working environment, the concentration of oxygen should be above 18% VOL; the content of combustible methane (CH4) in the air should be below 1.5%, and the methane concentration detector should be installed in the upper part of the coal yard where the exhaust airflow is concentrated to monitor the methane concentration in real time.

4.Working Principle and Product Introduction of Environmental Online Monitoring System for Enclosed Coal Yard

4.1 Schematic diagram of environmental online monitoring system for closed coal yard

Figure 1 Online environmental monitoring system for closed coal yard

4.2 Installation diagram of environmental online monitoring system equipment in closed coal yard

Figure 2 Installation of environmental online monitoring system equipment in the closed coal yard

4.3Equipment Introduction

4.3.1 XKCON-MT-W-156 explosion-proof main control cabinet

Figure 3 Main control cabinet

Product description

Model XKCON-MT-W-156 main control cabinet is a multi-functional intelligent monitoring host developed by our company for application sites with explosion-proof requirements. It supports various communication methods such as Ethernet, RS485, RS232, 4-20mA, 0-5V, etc. It has functions such as switch input, relay output, audible and visual alarm, historical record memo query, alarm record query, data packing transmission, etc.

The host control board adopts our self-developed XKCON-MC-B-V41 type main control board, which has the patent and software copyright certificate of independent intellectual property rights (registration number: 2018SR382811).

• The main control board meets industrial grade design standards to meet various industrial site use conditions

• Adopt embedded real-time operating system with high reliability and system stability

• Integrated PID, fuzzy control, artificial neural network, Kalman filter, multi-level sensor combination positioning algorithm and other industrial advanced algorithm library

• 2 x 485 interfaces, both configurable as Modbus RTU masters or slaves, with access to all types of our 485 transmitters

• With 1 RJ45 network port, you can upload the monitoring data from the host to the remote monitoring software platform

• With 1 channel 232 interface, can parse messages according to customer needs

• Automatic identification of RS485 interface from the device is working properly

• 8 expandable switch isolated input interfaces

• 6 way relay contact output, support normally open, normally closed output

• 6 analog signal inputs, support 4-20mA, 0-5V signal

• 1-channel audible and visual alarm output interface

• Support TCP/IP, UDP, Modbus RTU and other industrial communication protocols

• Message parsing and control function development can be customized according to customer needs

• The host interaction adopts large size color industrial touch screen with high resolution and fast refresh speed, which is very convenient and comfortable to operate and browse. Touch screen can set the alarm threshold, if the data exceeds the threshold will issue an acoustic and optical alarm. Support historical data and alarm record memorial query. Operation interface and functions support custom development.

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• Figure 4 Host display interface

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• Functional Features

• 1）220V AC power supply with circuit breaker and fuse protection

• 2）Built-in industrial-grade power supply module, can provide 24V/10A stable DC power output

• 3）Host unique ID number, easy to manage identification, can be matched with a variety of transmitters and software platforms provided by our company

• 4）2 x 485 interfaces, both configurable as Modbus RTU masters or slaves, with access to all types of our 485 transmitters

• 5）With 1 RJ45 network port, you can upload the monitoring data from the host to the remote monitoring software platform

• 6）With 1 channel 232 interface, can parse messages according to customer needs

• 7）Automatic identification of RS485 interface from the device is working properly

• 8）8-channel switch isolated dry contact input

• 9）6 way relay contact output, support normally open, normally closed output

• 10）6 analog signal inputs, support 4-20mA, 0-5V signal

• 11）1-channel audible and visual alarm output interface

• 12）12" color touch screen display, simple and friendly interface

• 13）Built-in data storage, 4G storage capacity

• 14）Support historical data memo query, alarm record query

• 15）Support alarm threshold setting, alarm site and remote confirmation

• Main Applications

• It is applied to industrial sites with explosion-proof requirements such as coal mines, power plants, petrochemicals, etc. It is used for collecting, processing, displaying and transmitting on-site environmental transmitter data, and providing real-time alarms according to the set threshold values.

• 4.3.2XKCON-TIS explosion-proof monitoring and temperature measurement infrared thermal imager

  

• Figure 5 Infrared thermal imager

• Product description

• XKCON-TIS series explosion-proof monitoring and temperature measurement type infrared thermal imager is a real-time monitoring and surveillance equipment integrating infrared thermal imaging, visible light and embedded processing system, this equipment can automatically inspect the running equipment, real-time monitoring, automatic warning and real-time access to equipment fault status thermal information, and automatically generate the corresponding temperature change report, built-in analysis function, automatically send the analysis results. It can also be shared to the main control cabinet on site according to the analysis results for alarm and control of external equipment, with the characteristics of non-stop, long-distance, safe and reliable, high detection accuracy, is one of the very effective means to achieve online monitoring and equipment status maintenance.

• Infrared thermal imager with Ethernet and 485 interface, can output the highest temperature of the site through the network port or 485 port, convenient to connect the control cabinet installed in the field real-time display of temperature information.

• Infrared thermal imager adopts uncooled infrared detector, mainly used for night, rain and fog weather conditions and harsh environment monitoring, can work around the clock, in the day and night and smoke, fog, rain, snow, dust and other conditions also have better performance.

• XKCON-TIS series explosion-proof monitoring and temperature measurement infrared thermal imager is suitable for places with ⅡA, ⅡB, ⅡC combustible gases, the ignition temperature group is T1-T6 group of zone 1, zone 2, combustible gases or vapors and air forming explosive mixtures, also suitable for the ignition temperature group is T1-T6 group of zone 20, zone 21, zone 22, containing combustible dust mixtures places. Such as: petroleum, chemical, mining, military, pharmaceutical, oil depots, ships, drilling platforms, gas stations, artillery production, food processing and storage.

• Functional Features

• 24V DC power supply

• High-level explosion-proof certification for a variety of harsh and high-risk locations

• Low power consumption, low power consumption, convection type heat dissipation design inside the body, can work uninterruptedly for a long time

• Made of 304 stainless steel, suitable for use in strong corrosive environments

• Explosion-proof, waterproof, dustproof design, suitable for indoor and outdoor installation, all-weather use

• Maximum temperature can be output via Ethernet and 485 interface

• Main Applications

• It is applied to video and temperature monitoring sites with explosion-proof requirements, such as petroleum, chemical, mining, military, pharmaceutical, oil depot, ship, drilling platform, gas station, flower artillery production, grain processing and storage, etc.

• 4.3.3 XKCON-MT-W-001 Probe rod type pyrometer

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• Figure 6 Probe Pyrometer

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• Specific parameters:

• 1）Operating voltage: 24VDC

• 2）Transmission mode: RS485, wireless transmission

• 3）Temperature measurement range: -55℃~125℃

• 4）Temperature measurement accuracy: ±1℃

• 5）Temperature measurement resolution: 0.1℃

• 6）Temperature probe rod length: 2 meters

• 7）Temperature measurement points in a single probe rod: 3

• 8）The meter head is designed with aluminum explosion-proof housing, and the probe rod is made of 304 stainless steel

• 9）Explosion-proof grade: Ex ib IIC T4 Gb

• 4.3.5XKCON-G600-CH4-001 Methane Concentration Detector

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• Figure 7 Methane concentration detector

• Specific parameters：

• 1）Detection method: Diffusion type

• 2）Measuring range: 0-100% LEL

• 3）Resolution: 0.1% LEL

• 4）Output form: RS485 communication

• 5）Linearity error: ≤±2%

• 6）Protection grade: IP65

• 7）Explosion-proof grade: Exd IIC T6 Gb

• 4.3.6XKCON-G600-CO-001 carbon monoxide concentration detector

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• Figure 8 Carbon monoxide detector

• Specific parameters：

• 1）Detection mode: Diffusion type

• 2）Measuring range: 0-2000PPM

• 3）Resolution: 1PPM

• 4）Output form: RS485 communication

• 5）Linearity error: ≤±2%

• 6）Protection grade: IP65

• 7）Explosion-proof grade: Exd IIC T6 Gb

• 4.3.7XKCON-G600-O2-001 oxygen concentration detector

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• Figure 9 Oxygen concentration detector

• Specific parameters：

• 1）Detection method: Diffusion type

• 2）Measuring range: 0-30%VOL

• 3）Resolution: 0.1%VOL

• 4）Output form: RS485 communication

• 5）Linearity error: ≤±2%

• 6）Protection grade: IP65

• 7）Explosion-proof grade: Exd IIC T6 Gb

• 4.3.8 GCG1000 dust concentration detector specific parameters

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• Figure 10 Dust concentration detector

• 1）Measuring range：（0-1000）mg/m3

• 2）Output signal: RS485

• 3）Measurement error: ±10%

• 4）Resolution: 0.1 mg/m3

• 5）Sampling flow error: ≤2.5%

• 6）Sampling flow stability: ≤±5%

• 7）Sampling flow rate: 2L/min

• 8）Operating voltage: 24V DC

• 9）Operating current: ≤200mA

• 10）Explosion-proof type: Intrinsically safe for mining