Water spray quantity control system and control method for semi-dry process flue gas desulfurization technology

Abstract

The invention relates to a kind of spraying water-amount controlling system and its method in stack gases desulfurization industrial art with semi-drying way, which belongs to the field of stack gases desulfurization industrial art in form of semi-drying. The feature of the invention is that as follows: in inlet flue, there is a relative humidity probe; according to the data of inlet flue, the data of outlet flue and the data of amount of water spray in desulfurizing tower, the data handling apparatus can calculate the temperature of near adiabatic saturation or the temperature of near-dew port in the outlet of desulfurizing tower, and then compares them with the corresponding setting value. Then by the difference of comparing, it can control the open and shut of electromagnetic valve in order to realize the precise control of spraying water amount. At the same time, the invention raises a full range method of controlling computers. Finally, the invention can prevent from the problem of being stained with dust and the corrosion problem of costly relative humidity probe efficiently, so it has high reliability and high economy.

Description

technical field [0001] The invention belongs to the technical field of semi-dry flue gas desulfurization, and in particular relates to a control system and a control method for the amount of water spraying in the semi-dry flue gas desulfurization process. Background technique [0002] At present, in the semi-dry flue gas desulfurization process, there are three commonly used water injection control systems: the first is to install a relative humidity sensor and a temperature sensor at the outlet of the desulfurization tower. Temperature, calculate the adiabatic saturation temperature of the flue gas, and control the amount of sprayed water by comparing the difference between the actual temperature of the flue gas and the adiabatic saturation temperature - the comparison between the near adiabatic saturation temperature and the set near adiabatic saturation temperature; the second is Install a dew point meter at the outlet of the desulfurization tower to measure the dew point...

AI Technical Summary

Problems solved by technology

[0003] The problems of the first system and the second system are: low reliability and economy

Specific analysis: the flue gas at the outlet of the desulfurization tower has a large dust content and high humidity, and due to unstable operating conditions, it often occurs that the flue gas at the outlet carries water droplets. During the operation, the relative humidity sensor or the sensor of the dew point meter It is easy to be covered by water and stick to smoke and dust. When this happens, the measured data is inaccurate and needs to be cleaned before returning to normal. This situation is unpredictable, so these two control systems are not reliable; and when When water covers the sensor, the sensor is easily corroded. Since the sensor of the relative humidity sensor or the dew point meter is expensive, the economics of these two control systems are not good

[0004] The problem with the third system is: low reliability and timeliness

Specific analysis: the accuracy of wet bulb temperature measurement is affected by the initial water temperature. Only when the initial water temperature is slightly higher than the real value of the measured wet bulb temperature can an accurate measurement be obtained, so the accuracy of the measurement result cannot be guaranteed Therefore, the control system is unreliable; the wet bulb temperature is generally measured manually, not continuous on-line measurement, so it cannot reflect the degree of humidification of the flue gas in the desulfurization tower in time

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