Draining and oxygen adding device for full-automatic heater

Abstract

The invention discloses a draining and oxygen adding device for a full-automatic heater. The device comprises the following components: a PLC; a pressure detector for collecting a pressure signal in pipeline at an oxygen adding point, and transmitting the pressure signal to the PLC; a dissolved oxygen content detector for collecting a dissolved oxygen content at a detecting point and transmittingthe dissolved oxygen content signal to the PLC; an oxidation-reduction potential detector for collecting an oxidation-reduction potential at the detecting point and transmitting the oxidation-reduction potential signal to the PLC; a hydrogen conductivity detector for collecting hydrogen conductivity at the detecting point and transmitting the hydrogen conductivity signal to the PLC; and a flow controller connected with an oxygen source and for controlling oxygen addition flow according to the PLC command. The invention also discloses a draining and oxygen adding method for the automatic heater. The oxygen adding device of the invention can avoid clogging of a drainage valve on a high-pressure heater shell side pipeline, and maintain safe and economical operation of the unit at an OT working conditions.

Description

technical field [0001] The invention belongs to the technical field of electric power and power engineering control, and in particular relates to a fully automatic heater hydrophobic oxygenation device and method. Background technique [0002] The structures of the water-steam circulation system of the once-through boiler and the drainage system of the high-pressure heater of the existing super (super) critical thermal power generating unit are as follows: figure 1 and figure 2 shown. [0003] Such as figure 1 As shown, in a once-through boiler, after the feed water of the deaerator is boosted by the feed water pump, it flows sequentially through the high-pressure heater tube side, the economizer, and the water wall system to complete the heating and evaporation of the feed water, and go through three stages of superheating The heating surface such as the boiler becomes superheated steam, which is sent out of the boiler and enters the high-pressure cylinder of the steam ...

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Problems solved by technology

[0005] The specific treatment process of the high-pressure heater drain system leads to flow accelerated corrosion (FAC) of the system, which occurs in a specific water vapor temperature range, high flow rate, and specific chemical conditions (reducing treatment and full volatilization treatment) , at this time, the oxidation-reduction potential (ORP) of the hydrophobic medium is very low (less than 0), and the temperature is between room temperature and 300°C. Water and carbon steel form a loose ferroferric oxide magnetic oxide film through an electrochemical reaction, which cannot Let the metal enter the passivation area to form a dense iron oxide protective film

Flow-accelerated corrosion makes the content of iron in the hydrophobic water high. The solubility of this ferroferric oxide film is the highest at about 150°C-200°C, and it has strong magnetism. It is used in valves and holes of some ferromagnetic materials, such as high-pressure heating Deposition and periodic clogging are formed at the outlets of the #1 high-pressure heater, #2 high-pressure heater and #3 high-pressure heater shell side, desuperheating water regulating valve, sampling valve, etc. The adjustment performance of the

[0006] The current oxygenation treatment is mainly aimed at the oxygenation treatment of feed water, and there is no related report on the oxygenation treatment for hydrophobicity

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