A kind of optimal control method for furnace desulfurization of circulating fluidized bed

Abstract

The invention belongs to the technical field of circulating fluidized bed boilers and discloses a furnace desulphurization optimization control method for a circulating fluidized bed. An optimization control system of the furnace desulphurization optimization control method comprises a data communication subsystem, a sulfur content online correction subsystem, a sulfur dioxide prediction subsystem and a limestone control subsystem; data interaction is performed on the data communication subsystem and OPC server communication software of a DCS system; the sulfur content online correction subsystem is connected with the data communication subsystem; the sulfur dioxide prediction subsystem is connected with the sulfur content online correction subsystem and the data communication subsystem; the limestone control subsystem is connected with the sulfur dioxide prediction subsystem and the data communication subsystem. According to the furnace desulphurization optimization control method for the circulating fluidized bed, a sulfur dioxide prediction model and a coal sulfur content self-adaptive correction method are established and accordingly the feeding amount of the limestone can be timely and dynamically adjusted, the excess emissions of the sulfur dioxide and the excessive use of the limestone and other resources are avoided, and the practical value in engineering is high.

Description

technical field [0001] The invention belongs to the technical field of circulating fluidized bed boilers, and in particular relates to an optimal control method for desulfurization in a circulating fluidized bed furnace. Background technique [0002] Circulating fluidized bed combustion technology is one of the clean coal combustion technologies. This technology adds coal and desulfurizer to the bed of the combustion chamber, and blasts air from the bottom of the furnace to suspend the bed for fluidized combustion. Today, when environmental protection is attracting attention, fluidized bed combustion has low NO due to low-cost desulfurization technology in the furnace and low-temperature combustion x The inherent characteristics of emissions make circulating fluidized bed boilers the preferred thermal equipment in high-sulfur coal areas. As the largest developing country in the world, my country currently ranks third in energy production and second in basic energy consumpti...

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Problems solved by technology

Obviously, this concentration adjustment method has serious hysteresis and cannot fundamentally play the role of adjustment and control; secondly, due to the increasingly stringent requirements of the country on flue gas emission indicators, the desulfurization efficiency of most CFB boilers in China is still only At about 80%, if you want to achieve a higher desulfurization efficiency, you need to add a large amount of desulfurizer, a large amount of limestone will decompose in the material layer, causing the bed temperature to drop, affecting the load of the boiler, and the large consumption of limestone will make Ca The / S molar ratio increases, and the operating cost increases

Moreover, excessive desulfurizer will bring a large amount of additional ash and physical heat loss, and at the same time increase the wear of the furnace, affect the combustion conditions and the efficiency of the boiler, thereby increasing the cost and affecting the economy of the boiler; thirdly, the coal quality Poor adaptability to changes, resulting in high limestone consumption and high operating costs

After the change of coal quality, the fixed Ca / S ratio is still used to adjust the feeding amount of limestone, resulting in a serious waste of limestone raw materials and a substantial increase in cost

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