Chemical cleaning agent for superheater heat exchange pipe of station boiler

A technology for power station boilers and superheaters, which is applied in the field of chemical cleaning agents and chemical cleaning agents for heat exchange tubes of power station boiler superheaters, can solve problems such as failure to achieve cleaning effects, cleaning failures, and unit ring damage, and achieve excellent cleaning characteristics. Effect

Active Publication Date: 2012-10-10
XIAN THERMAL POWER RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 1) Most power boilers adopt a π-shaped arrangement, and the superheater contains a large number of vertically arranged U(W)-shaped tubes. The cleaning residue is easy to deposit and block at the bottom of the U(W)-shaped tubes, resulting in cleaning interruption or cleaning failure;
[0004] 2) The heat exchange tubes of the superheater involve a variety of metal materials, including various ferritic steels (such as T22, T23, T91, etc.) Therefore, during chemical cleaning, intergranular corrosion and stress corrosion of austenitic stainless steel, as well as corrosion of welded joints of dissimilar steels, may cause crack damage at the corrosion site or decrease in the mechanical properties of the material, thus causing damage to the unit. or cause safety hazards;
[0005] 3) Since the boiler superheater operates under high temperature and high pressure steam conditions, the oxides formed on the inner wall of the heat exchange tube of the superheater have the characteristics of large amount, dense structure, and multi-layer structure, so the oxides are difficult to dissolve. Cannot achieve good cleaning effect

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] According to the mass percentage, it contains 1.0% MAC, 0.3% corrosion inhibitor, 0.5% reducing agent sodium isoVC, 0.1% surfactant sodium dodecylbenzene sulfonate, and the balance is desalinated water.

[0015] Among them, MAC is composed of the following substances in mass percentage: methanesulfonic acid accounts for 5%, nitrilotriacetic acid accounts for 20%, diethylenetriaminepentaacetic acid accounts for 20%, ethylenediaminetetraacetic acid accounts for 10%, and the balance is pH Regulator ammonia water;

[0016] The corrosion inhibitor is composed of the following substances in mass percentage: 25% hexamethyleneamine, 10% urotropine, 20% hydrazine, 20% mercaptobenzothiazole, 20% benzotriazole, and the balance for desalinated water;

[0017] Take 100mL of the cleaning agent of this example, raise the temperature to 95°C, and under airtight conditions, clean 1.5g of the peeled off scale of the austenitic stainless steel superheater after operation for 24 hours, an...

Embodiment 2

[0019] According to the mass percentage, it contains 10% MAC, 0.3% corrosion inhibitor, 1.5% reducing agent hydrazine, 0.1% surfactant alkylphenol polyoxyethylene ether, and the balance is desalted water.

[0020] Among them, MAC is composed of the following mass percentages: methanesulfonic acid accounts for 10%, nitrilotriacetic acid accounts for 30%, diethylenetriaminepentaacetic acid accounts for 30%, ethylenediaminetetraacetic acid accounts for 15%, and the balance is pH Regulator ammonia water;

[0021] The corrosion inhibitor is composed of the following substances in mass percentage: hexamethyleneamine accounts for 5%, urotropine accounts for 30%, hydrazine 25%, mercaptobenzothiazole 10%, benzotriazole 5%, and the balance for desalinated water;

[0022] Take 180mL of the cleaning agent of this example, raise the temperature to 85°C, and clean the T23 steel and austenitic stainless steel TP347 superheater tube samples after operation under airtight conditions. After 50...

Embodiment 3

[0024] Contains 20% MAC, 0.3% corrosion inhibitor, 1.5% reducing agent isopropyl ketone oxime, 0.1%wt surfactant alkylphenol polyethylene oxide ether by mass percentage, and the balance is desalted water.

[0025] Among them, MAC is composed of the following mass percentages: methanesulfonic acid accounts for 15%, nitrilotriacetic acid accounts for 40%, diethylenetriaminepentaacetic acid accounts for 25%, ethylenediaminetetraacetic acid accounts for 12%, and the balance is pH Regulator ammonia water;

[0026] The corrosion inhibitor is composed of the following substances in mass percentage: 10% hexamethyleneamine, 15% urotropine, 40% hydrazine, 15% mercaptobenzothiazole, 10% benzotriazole, and the balance for desalinated water;

[0027] Get the cleaning agent of 180mL present embodiment, and add 50mg / LCl - and 2.4g of oxide scale, heated to 65°C, under airtight conditions, after cleaning, the TP347 and Super304H stainless steel corrosion indicator test pieces had no corrosi...

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PUM

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Abstract

The invention relates to a chemical cleaning agent of a superheater heat exchange pipe of a station boiler, which comprises the components by mass percent: 1.0-50.0% of MAC, 0.1-0.5wt% of corrosion inhibitor, 0.05-1.5wt% of reducing agent, 0.05-0.2wt% of surfactant and de-mineralized water, wherein the MAC is a key component, and the other components are auxiliary components. The process condition is to control pH at 1.0-7.0. The cleaning formula has an excellent dissolving and dispersing effect on scale of various superheater heat exchange pipes, and simultaneously can control the material corrosion within a safety range and standard set value. The chemical cleaning agent is suitable for chemical cleaning of superheater heat exchange pipes of various station boilers, boilers and other equipment.

Description

technical field [0001] The invention belongs to the chemical cleaning agent in the field of chemical industry, and in particular relates to a chemical cleaning agent for heat exchange tubes of superheaters of power plant boilers. Background technique [0002] The peeling and clogging of the steam side of the superheater heat exchange tube of supercritical and ultra (super) critical unit boilers have become increasingly prominent, seriously affecting the safe and stable operation of thermal power plants. The chemical cleaning technology can remove the scale on the water vapor side of the heat exchange tube of the superheater, and can greatly improve the thermal efficiency of the boiler. However, due to the great difference between the structure, material and operating conditions of the superheater and the boiler body, there are the following technical problems in the chemical cleaning of the heat exchange tubes of the superheater using the existing formula and process for cle...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23G1/06C23G1/08
Inventor 邓宇强张祥金曹杰玉龙国军林卫丽倪瑞涛祁东东宋飞
Owner XIAN THERMAL POWER RES INST CO LTD
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