Delta Automation and Monitoring System Enhances Efficiency and Safety for Coal-fired Hot Water Boiler

Since the beginning of the industrial age, the boiler has been an important device for providing heat. Today, boilers are used by most manufacturing and service industries. While based on the same principle, the boiler functions for different purposes in industry such as the dyeing, printing, and drying processes in manufacturing, and for services used in our daily lives, including steaming, water heating, house heating, and more.

A coal-fired hot water boiler uses water as a medium for thermal conduction. The coal-fired furnace heats the water when it flows through the boiler tubes, and the equipment absorbs the heat from the steam produced during the water cooling process. The cooled water is then sent back to the boiler by pump for reheating. The process of water circulation for heat absorbing and dissipating provides a supply of heat.

The control system of the coal-fired boiler sets the outlet water temperature based on the ambient environment temperature. According to the difference between outlet water temperature and designed temperature, the control system adjusts feeding the coal amount to keep a constant outlet water temperature. It also adjusts the draft fan rotate speed by PID algorithm for constant negative hearth pressure with feedback signals for blower rotate speed and hearth pressure value.

A customer uses the Delta High Performance Mid-range Programmable Logic Controller (PLC) AH500 Series for host controller and calculation and the DOP-B Series HMI as the user interface. Based on feedback from sensors and meters on the environmental conditions and the device presets, the AH500 Series controls the operation and calculation for circulating pump, make-up water pump, grate, blower, draft fan and other equipment for boiler operation.

Overall operation data is uploaded to the centralized control room through the Industrial Ethernet Switch DVS Series. Delta's SCADA system DIAView is then used for real-time monitoring of the boiler to ensure proper operation. In addition, Fan/Pump Vector Control Drive CP2000 Series conducts variable frequency pump and fan control to achieve energy savings.

The PLC AH500 series provides multi-parameter input and output to control the multiple devices of the boiler. It also provides an interlock protection function to ensure secure operation by sending out an alarm when the temperature or other critical variables exceed the standard value. The DIAView SCADA system provides real-time monitoring of the boiler operation status to improve safety and historical data analysis to optimize the control system. In addition, Fan/Pump Vector Control Drive CP2000 Series controls the motor speed based on the operation needs and thus saves energy. The Delta solution for the coal-fired hot water boiler is praised by customers and provides a perfect model for energy-efficient boiler applications.