Coking waste-gas desulfurization process optimized control method

Abstract

The present invention relates to a coking waste-gas desulfurization process optimized control method applied to a desulfurization and denitrification integrated process device. The method includes the following steps that: a current working condition is determined through using a fuzzy identification algorithm according to flue gas temperature, flue gas flow rate, flue gas oxygen content and sulfur dioxide concentration at the entrance of the desulfurization and denitrification integrated process device; the optimal pH value of a desulfurization absorption liquid under the current working condition is determined by using a variable step size progressive decrease method; the amount of ammonia compensation under the current working condition is determined through using a neural network model; the amount of ammonia control under the current working condition is determined through using an inner membrane control method and according to the sulfur dioxide concentration at the entrance of the desulfurization and denitrification integrated process device; and the pH value of the desulfurization absorption liquid is controlled according to the amount of ammonia compensation and the amount of ammonia control and based on the optimal pH value of the desulfurization absorption liquid. With the coking waste-gas desulfurization process optimized control method provided by the embodiments of the invention adopted, the fastness and accuracy of control are improved, and the desulfurization and denitrification integrated process device can operate under a most economical and environmentally friendly state, and the operating cost of the desulfurization and denitrification integrated process device can be reduced.

Description

technical field [0001] The invention relates to the technical field of industrial control, in particular to an optimal control method for coking waste gas desulfurization process. Background technique [0002] Sulfur dioxide and nitrogen oxides are the main air pollutants and the main factors affecting air quality. my country is the largest coking producer in the world. Due to historical reasons, for a long time, the coking flue gas in the domestic coking industry has not been desulfurized and denitrified, and has been directly discharged into the atmosphere, which has become one of the important sources of air pollution. The "Emission Standard of Coking Chemical Pollutants", which was officially implemented on January 1, 2015, puts forward strict and clear quantitative requirements for the emission indicators of sulfur dioxide and nitrogen oxides in the coking chemical industry. [0003] A coking plant took the lead in adopting the wet ammonia forced turbulent desulfurizat...

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Problems solved by technology

However, the control of the desulfurization process at this stage has the following problems: 1. The controlled variable is directly the SO in the purified flue gas 2 Concentration, and only adopt simple PID (proportional-integral-derivative control, P stands for proportional, I stands for integral, D stands for differential) control, the overshoot and hysteresis are extremely large, and the stability and accuracy of the control cannot be guaranteed at all; 2. The coking process has very complex production conditions, resulting in its multi-working condition characteristics. The temperature, flow rate, concentration and other indicators of flue gas vary greatly under different working conditions; 3. The process requirements only stipulate that the pH value is 4.5- 6.5, the range is too large and the difference under different flue gas conditions is not considered, resulting in a large waste of raw materials and even ammonia escape, which is not conducive to the economical and environmentally friendly operation of the desulfurization and denitrification integrated process device

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