The Design And Implamentation Of CFB Limestone Injection Desulfurization System Based On DCS Control

Circulating fluidized bed (CFB) is a new kind of clean coal combustion technology, and it can significantly reduce the concentration of SO₂ emissions. With large-capacity boilers, high parameters of development and improvement of environmental protection requirements, in particular attention should be given to the effect of CFB Desulphurization. At the same time, because the existing CFB boilers did not have a considerable portion of desulphurization, the exploration for CFB furnace desulphurization technology and the research for desulphurization system have practical significance.In this paper, starting from practical conditions, as the reconstruction engineering to a power plant 75t/h circulating fluidized bed boiler furnace CaCO3 spout desulphurization for the background, the main research work carried out as the following:Firstly, through analysis of the circulating fluidized bed boiler combustion process, expatiated the mechanism of its desulphurization, and discussed desulphurization characteristics and the impact of factors. Combining with the actual working condition, selected the way to the limestone feedstock and designed system technics process.Secondly, in this paper, through many locale research and practical experience, according to system design requirements and the comparison of various control devices, selected the desulphurization control system's main control equipment. According to conditions of circulating fluidized bed furnace CaCO3 spout desulphurization process, implemented the locale process of decentralized control and centralized management of information. The overall control system structure and function of the design was brought forward.Thirdly, according to the system structure and function, designed a set of desulphurization DCS system to meet the requirements. The system should meet the power regulations and criterion, in accordance with the overall control level of power plant and meet the power plant operation and management requirements. DCS control and continuous monitoring of flue gas was implemented.Finaly, the aim of the paper was to control the let concentration of SO₂. Combined with system process and main factors of the impact of desulphurization efficiency, studied the control of quantity of the feed to the limestone and boiler bed temperature control strategy.The design of DCS control system in this paper was a new effective system, on-site testing results indicated that the circulating fluidized bed boiler desulphurization control reached the design requirements, the system was running stable. The design of programs and methods the article outlined has a certain reference for the future similar to circulating fluidized bed furnace CaCO3 spout desulphurization design and the transformation of the old power plant.