Upgrade of coal mine air compressor control system Di Chuanmin (Baodian Coal Mine of Yankuang Group, Jining 273500, Shandong Province) 1 Project Introduction Baodian Coal Mine Machine Room has 6 sets of L250 screw air compressors of compare company, each screw air compressor There are Delcos3100 controllers. The main functions of the Delcs3100 controller include: control air compressor operation, automatic switching of loading and unloading, online display of air compressor operating status and process data, anti-reverse protection, low oil level, exhaust temperature, Oil filter blockage, air intake filter blockage and various maintenance time alarms.
However, this control system has the following shortcomings: (1) Remote centralized control is not realized, and the controllers and related intelligent meters of each air compressor are distributed and monitored on the spot, resulting in inconvenient use and waste of human resources.
(2) Closed-loop continuous control of unrealized pressure is easy to cause air compressor idling and pressure fluctuation, which makes energy consumption large and control precision low.
(3) There are few parameters that can be monitored. Once a fault occurs, it is difficult to locate the fault.
(4) The lack of monitoring and display of electrical parameters does not meet the requirements for on-site observation and maintenance.
(5) The display of the controller is a monochrome display, and the information shown is abstract, which is not conducive to the use of the operator.
(6) Without the LAN function, the operating data of the system cannot be uploaded to the company management network in real time.
In order to solve the above problems, the original control system has been upgraded.
Before the transformation, the six sets of equipment were operated independently. Each set of air compressors needed to be operated locally by the operators on their respective Delcos3100 controllers to achieve start-stop control. All real-time operational data can only be read by the operator. The instrument is obtained, it is very inconvenient to use, and the data is acquired in real time. After the transformation, all equipment can be centrally controlled through the network. The operational data and alarm information can be displayed on the touch screen. The Ethernet process data can also be uploaded to the company management network. The automation level is greatly improved, and the operation and maintenance costs are greatly reduced. Can save a lot of money for the company.
2 upgraded control system constitutes 2.1 equipment selected by the control system (2) man-machine interface: Siemens MP277 touch screen.
Data exchange between the 3100 controller and the smart meter and the main controller.
Uploaded to the company management network to meet the requirements of the company's information management. 2.2 The function of the main equipment is the system configuration and network structure diagram. PROFIBUSDP and MODBUS are used as the main communication network to connect the various parts of the system. The functions of the main equipment are as follows: system 1/0 signal, realize logic control and network communication function, for its 2012.07* Zhong 1 Decoration 4 New Domain Shui Gong also provides instructions or process data for his equipment, which is the core of the control system.
The DP network is connected with the PLC, and the monitoring functions of the six sets of air compressors are displayed together to realize the functions of remote control, remote setting, remote data acquisition and remote alarm recording of the air compressor, which is convenient for the use of operators.
The controller and various intelligent meters all have MODBUS communication interface. The conversion module converts the MODBUS protocol into the standard PROFIBUS DP protocol, which is convenient for the S7-300 system to read. This greatly enhances the compatibility of the system and improves the system integration. degree.
The 011 integrates a 1.1 communication interface, and converts the MPI protocol into a TCP/IP protocol through the ETH-MPI module to implement connection with the management network.
Ethernet field instrument system configuration and network structure diagram The whole system fully embodies the concept of Siemens TIA (Total Integrated Automation), and unifies the original independent discrete units into the same network, realizing remote centralized control.
3 Control system completed functions Air compressors have been operated on the spot. This method has many drawbacks, and it does not meet the trend of today's electrical automation technology development. It can be ideally solved by PLC expansion and programming capabilities. this problem. First, at the physical layer, the devices that need to be networked are connected according to the technical requirements; then, specific communication programs for different devices need to be loaded in the PLC to realize real data access, so that they become dispersed and concentrated, and the operator does not have to go again. The device is separately controlled by the machine, and only one touch screen can control the start and stop of all devices, monitor the running status of all devices, and read the required process data. The application of new technology not only reduces the labor intensity, but also improves the working efficiency of the operators. At the same time, it also facilitates the maintenance and maintenance of the equipment and provides stable and reliable power support for the gas equipment. Example of actual monitoring screen: Monitoring screen example 4 Future improvement and upgrading The loading and unloading control of the existing system needs to be controlled by the internal pressure switch. The exhaust pressure of the air compressor changes with the load, and the gas consumption increases. The pressure will decrease. When it is lower than the lower limit, the air compressor will start to carry the load; after the air compressor runs through the load, the pressure will rise. When it is higher than the upper limit, the air compressor will start to be unloaded. The whole work process is in the process. Repeated switching between the "loaded" and "unloaded" states. The working current when loading is close to the rated current of the motor. The idle current during unloading is about 30% and 50% of the rated current. This part of the energy is not effectively utilized by the air compressor, but the idle loss of the motor at the rated speed. This method of pressure regulation by means of pressure switch can meet the working requirements of gas equipment, but its adjustment precision is low, pressure fluctuation is large, air compressor always works at rated speed, mechanical wear is large, power consumption Yet.
If you use variable frequency speed regulation, you can not only save energy, but also improve control accuracy. The frequency converter enables the motor to be “soft-startedâ€, which reduces mechanical wear and equipment loss. The maintenance cycle and service life of the air compressor are greatly extended, and the combined operation cost is significantly reduced.
4.1 Function of the inverter in energy saving (1) The air compressor will meet the minimum pressure required by the production equipment as the lower limit of the set pressure. The inverter adjusts the speed of the air compressor according to the difference between the pressure feedback and the pressure setting. Even the unloading operation of the air compressor is no longer needed, saving energy.
(2) Since the conventional air compressor cannot eliminate the possibility of long-term operation under full load conditions, the capacity of the motor can only be determined according to the maximum demand, so the selection capacity is generally large. In actual operation, the proportion of light load operation time is very high. On the medium-deep hole blasting technology of coal mine excavation Liu Xiaogang (Nanjing Coal Mine of Yanzhou Coal Mining Co., Ltd., Zoucheng 273515, Shandong Province speeds up the operation progress. Article first The medium-deep hole blasting technology and its advantages and disadvantages are summarized. The parameters of the medium-deep hole blasting technology and the construction precautions are introduced in detail. The causes of the explosion-preventing and the treatment measures are analyzed, and the blasting operations can be carried out for the relevant operators. Provide certain.
As an extension of shallow-eye blasting, the medium-deep hole blasting technology can not only accurately control the blasting output, but also the lumps generated by the blasting are generally scattered on the edge and surface of the blasting pile, which is easy to perform secondary crushing in time, and the technical advantage is very obvious. In the process of coal mining and mining, due to the long-term use of some roadways, it is greatly affected by the mine pressure in the mine. The medium-deep hole blasting technology can effectively improve the cycle footage and shorten the time of auxiliary operations. Through the medium-deep hole blasting technology, it is possible to improve the construction schedule and construction quality without changing the way of excavation and the excavation equipment, and ensure that the coal mine excavation production is carried out quickly, safely and smoothly.
1 Study of medium-deep hole blasting technology 1.1 Setting of blasthole in deep hole operation For the determination of blasthole depth in medium-deep hole blasting, comprehensive consideration should be given to the nature of underground rock mass, the form and size of roadway section, and the use of variable frequency speed regulation for blasting to improve operating efficiency. ,reduce waste.
(3) The original adjustment method can not reduce the operating power of the motor even when the demand is small. After the frequency conversion speed regulation is adopted, when the demand is small, the rotation speed of the motor can be reduced, and the operating power of the motor can be reduced, thereby further realizing energy saving.
4.2 The adjustment system consisting of PLC, frequency converter, pressure sensor and motor can make the air compressor output pressure stable compressed air user setting and pressure feedback through the PID program calculation in PLC, and transmit the frequency setting value to the inverter. The adjustment of the motor speed is achieved, which in turn affects the exhaust pressure, and finally the exhaust pressure is consistent with the user set pressure. The system is always performing calculations and dynamic adjustments, which greatly reduces or even eliminates pressure fluctuations and improves the quality of the gas supply.
5 Project Experience The implementation and commissioning of this project is a successful application of Siemens Totally Integrated Automation in the field of coal mine air compressors. Through the upgrading and modification of the control system, the automatic control level of the air compressor is greatly improved, and the running cost is saved.
The rich functionality and high flexibility of Siemens products are impressive. The smooth implementation of this project also benefits from the high flexibility of the S7-300PLC. The various communication protocols are unified by programming to achieve integrated control.
Things are not perfect, there are still some areas for improvement in the project. We believe that through continuous technological innovation, we will be able to see the air compressor control system with more powerful functions, more advanced performance and more convenient use.
(Responsible editor: Wensen) 2012.07* 1 decoration 4 new domain Shuigong also
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