The Design Of The Desulphurization Control System In The Thermal Power Plants

In China, the annual emissions of sulfur dioxide currently ranks first in the world, and the mount of sulfur dioxide emissions has reached21.176million tons during2012, of which more than50%of the sulfur dioxide is derived from nationwide coal-fired power plant units. Up to2012, China’s installed capacity of thermal power plants has reached819million kilowatts, which accounts for71.55%of total installed capacity. The thermal power plant desulfurization currently is still the main way to control sulfur dioxide emissions in China. To protect the environment and reduce acid rain pollution caused by sulfur dioxide, thermal power plant FGD device and its control system will play an important role of making the SO2emissions meeting the national standard.This paper mainly focuses on the design and application of flue FGD control system on power plants. First, we state the process techniques of FGD applied in power plants, especially the process of limestone-gypsum wet FGD control system. Then we introduce the design principles and rules of wet flue FGD control system used in power plants, and details the basis principles, structure and design of DCS.Through the full aware of wet limestone-gypsum desulfurization technology and distributed control systems, and combined the actual situation of desulfurization project’s in Fuzhou power plant, the desulfurization control system for2×1000MW ultra-supercritical units in Fuzhou power plant was designed. The structure of the whole desulfurization control system was discussed in detail. While Hollias MACS control system was designed and applied, the hardware and software configuration of desulfurization control system and control methods and strategies of all kinds of functional modules were described, especially for the desulfurization control system of anti-interference design, so as to the ensurence of stable and reliable operation of the system.Finally, this paper has described FGD control system on its debugging and management methods, and summarized the design experience of FGD control system. Based on the actual requirements and problems, the control level of DCS control system is optimized to enhance the availability to FGD control system, which can not only ensure the economical efficiency and stability, but also meet the environment requirements.