A kind of medium and low pressure boiler phosphate dosing control method

Abstract

The invention provides a dosing control method of phosphate in a middle-low pressure boiler. The dosing control method of phosphate in the middle-low pressure boiler is especially suitable for water quality monitoring of a middle-low pressure waste heat type boiler, wherein the steam pressure at the boiler outlet of the boiler is below 6.0 MPa; and the method can be used for controlling the automatic dosing amount of phosphate according to an electrical conductivity value. According to the dosing control method of phosphate in the middle-low pressure boiler, the adding amount of phosphate meets the requirement under any condition.

Description

technical field [0001] The present invention relates to the field of water quality monitoring for medium and low pressure boilers. Specifically, the present invention relates to a phosphate dosing control method for medium and low pressure boilers. Water quality monitoring for medium and low pressure waste heat boilers below 6.0 MPa, and the automatic dosing of phosphate can be controlled according to the conductivity value. Background technique [0002] In the boiler water treatment process, phosphate dosing is the most common treatment method. Phosphates prevent scaling and corrosion in drum boilers. However, the content of phosphate in the drum boiler needs to be clearly regulated, and the addition of too much or too little will increase scaling and corrosion. At present, the phosphate content is still judged by sampling analysis or online phosphate analyzer, and then the dosing amount is adjusted according to the phosphate content. [0003] The prior art generally has...

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Problems solved by technology

[0006] However, because the above method is limited by the analysis time and frequency, it is difficult to ensure that the dosing amount meets the regulations around the clock

[0007] Because, among the two methods mentioned above, the first method is more accurate in analysis accuracy, but because the operating conditions of the unit will change at any time, such as changes in water supply; changes in steam drum blowdown; heating start and stop; power generation load fluctuations; Changes in the concentration of the medicine box during dispensing; both will cause a large change in the phosphate content in the system

On the other hand, it is obviously difficult to achieve time tracking by adjusting the dosing amount after manual analysis in the laboratory.

[0008] In addition, the second method is generally less used because it requires capital and maintenance personnel investment, and the analysis of the online instrument also takes 8 minutes.

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