In daily production, the fuel composition and heat load vary greatly with the seasons, so the amount of air required for boiler fuel also varies greatly. Therefore, more than 80% of the time of the year, the fan runs under low load. How to properly configure the operating conditions of exhaust air, blast, induced air and water pump motors will greatly help save energy, improve working environment and labor intensity. Therefore, the DCS system composed of industrial control computers is used to sample the fuel system and closed-loop control has been widely used in boiler automatic control systems.

    The SXMC-110 series coal-fired boiler DCS automatic monitoring system designed and developed by our company uses a microcomputer-based programmable controller to complete data collection and system control. The control system conducts centralized monitoring, management, and automatic sequence control of the entire process system. The logic design of sequence control ensures that it meets the control requirements of the process system. Ensure the safe, reliable and economical operation of the start-up boiler. At the same time, the control system can be connected to the upper-level public DCS system of the whole plant through communication, so as to realize the centralized control of the entire process system in the centralized control room, which can meet the requirements of unattended on-site.
Working Principle of DCS Automatic Monitoring System for Coal-fired Boiler
    1. There is a substantial difference between the DCS control system and the use of an ordinary single inverter. The former is inputted into the control system by a set pressure (or temperature) signal, and after data retrieval, instructions are issued to enable the operation of the air supply, induced air, and grate motors. , It can continuously adjust the speed according to the change of steam consumption, coordinate operation, and achieve optimized energy-saving combustion. The latter is controlled by human will, with large deviations in mastering data, and the effect is not as good as the former.
    2. The DCS control system is equipped with a special operating program for the boiler to track steam flow, feed water flow, steam pressure, feed water pressure, steam drum level, furnace temperature, furnace negative pressure, and exhaust gas temperature in real time. It has real-time display values such as ultra-high/ultra-low water level, ultra-high pressure, ultra-positive/ultra-negative negative pressure, ultra-high/ultra-low flow, and limit water level.
    3. The system sets the steam working pressure value; when the power-on command button is activated, the system first retrieves the current steam working pressure value. When the pressure value is less than (or equal to) the rated value, the system starts to work, first start the induced draft fan at a low speed for a few seconds (this The value can be set at will) After the blower motor and grate motor are started, in order to meet the negative pressure requirements of the boiler furnace, the operation between the blower motor and the induced draft fan motor is pre-set to perform macro-control, and the furnace patrols the combustion status in the furnace. Make fine adjustments to the boiler position, that is, adjust the thickness of the coal seam, distribute the air volume of the air distribution chamber, etc., to make the combustion more perfect and the vapor pressure more stable.
    4. With the operation of the boiler system, the steam pressure gradually increases, and the system command operation frequency decreases accordingly. The DCS system continuously adjusts after receiving the information during operation, finds the appropriate energy-saving operation point, and maintains a relative balance between the use of steam and the steam supply system.