The metal corrosion of the boiler feedwater system in thermal power plants directly affects the safety and economic operation of the boiler and thermal system. Although it does not cause immediate system failure, it can lead to the premature scrapping of thermal system equipment and shorten its service life. The dosing device is designed to meet the needs of water treatment in boilers. It adopts two working modes: on-site manual and remote automatic. Measures such as adding phosphate to the boiler and ammonia to the boiler feedwater are taken to prevent boiler scaling, remove dissolved oxygen from the feedwater, increase the pH value of the feedwater, and prevent metal corrosion of the feedwater. This is of great significance for ensuring the safe and economical operation of power plants.
The lower computer of the system adopts Siemens PLC as the controller, and the upper computer adopts Advantech industrial control computer to achieve fully automated control of the entire dosing process.


1. Hardware composition of microcomputer monitoring system for chemical water treatment in power plants
A typical control system diagram is shown in the above figure. PLC, also known as programmable controller, is installed in the local control cabinet. Its CPU is a redundant structure (optional), stable and reliable. It collects information and issues instructions to each dosing point through remote IO modules. The industrial computer communicates in real-time with the PLC, and the operator monitors the automatic dosing process through the human-machine interface (HMI) of the "Chemical Dosing Automatic Control System" installed in the industrial computer.

2. Working principle diagram of microcomputer monitoring system for chemical water treatment in power plant

3. Example of Interface for Chemical Dosing Automatic Control System