Ammonia spraying apparatus based on sound wave measuring temperature field and flow field and working method of ammonia spraying apparatus

Abstract

The invention discloses ammonia spraying apparatus based on a sound wave measuring temperature field and a flow field. The ammonia spraying apparatus comprises the sound wave measuring temperature field, a flow field component, an intelligent feed-forward controller, a first comparator, a second comparator, a third comparator, a proportional integral (PI) regulator, an ammonia spraying main valve,a selective catalytic reduction (SCR) reactor, an unpredictable disturbance observer, an NOx concentration prediction controller and a multi-model predictive controller; the sound wave measuring temperature field and the flow field assembly comprise an acoustic wave sensor, a data acquisition device and an industrial control computer. According to the apparatus provided by the invention, an acoustic wave method is adopted to measure the smoke temperature field and the flow field, the intelligent feed-forward controller is designed according to the change of the NOx concentration at an inlet,the NOx concentration at a desulfurization outlet and the flow field of flue gas, and parameters of the feed-forward controller are dynamically modified so as to realize accurate compensation of totalworking conditions for measurable disturbance, so that ammonia spraying control is more timely and accurate.

Description

technical field [0001] The invention relates to the technical field of exhaust gas treatment, in particular to an ammonia injection device and a working method thereof based on sound wave measurement of temperature field and flow field. Background technique [0002] Many foreign scholars have added a feed-forward link to the traditional PID control loop when conducting research on the control of SCR denitrification systems, and introduced the NOx flow rate at the inlet and outlet of the SCR reactor as the correction of the required ammonia amount. The principle is similar to the fixed molar ratio control method. The NOx flow at the reactor inlet is obtained by multiplying the NOx concentration at the inlet of the SCR reactor by the flue gas flow, and then the required ammonia flow is calculated by using the molar ratio. [0003] Most of the above studies on the control methods of SCR denitrification systems are based on traditional PID control. Traditional PID control has b...

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Problems solved by technology

Since the denitrification system is a nonlinear system with a large lag, PID-based post-control will cause problems such as high ammonia slip rate and large NOx fluctuations under variable load conditions.

[0004] The traditional control method will cause the following problems: high ammonia escape at the denitrification outlet, easy to cause blockage of the air preheater, frequent action of the ammonia injection master valve, and large fluctuations in NOx emission data, which will bring difficulties to the economic and safe operation of the power plant

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