阅读说明：本技术 一种针对垢样含有磷灰石或/和磷酸钙垢且系统含有奥氏体钢的清洗剂及其应用 (Cleaning agent for scale containing apatite or/and calcium phosphate scale and system containing austenitic steel and application thereof ) 是由 杜越 盛丽雯 张建斌 姜波 于 2019-10-18 设计创作，主要内容包括：本发明公开一种针对垢样含有磷灰石或/和磷酸钙垢且系统含有奥氏体钢的清洗剂,由清洗剂A和清洗剂B组成,所述清洗剂A由柠檬酸、氨水、2-巯基苯并噻唑、氢氧化钠、乙二醇、十二烷基苯磺酸钠、D-异抗坏血酸钠、磷酸三丁酯和去离子水组成；所述清洗剂B由乙二胺四乙酸、氨水、咪唑啉季胺盐、水合肼、磷酸三丁酯和去离子水组成。同时,本发明还公开将所述清洗剂用于发电厂中垢样含有磷灰石或/和磷酸钙垢且系统含有奥氏体钢/的锅炉的化学清洗,包括以下步骤：(1)清洗剂A清洗；(2)清洗剂B清洗。清洗后不会对奥氏体钢产生晶间腐蚀,对磷灰石和磷酸钙垢的清洗效果好,经过两步清洗就可完成清洗钝化,形成的钝化膜保护性能较好。(The invention discloses a cleaning agent for a scale sample containing apatite or/and calcium phosphate scale and a system containing austenitic steel, which consists of a cleaning agent A and a cleaning agent B, wherein the cleaning agent A consists of citric acid, ammonia water, 2-mercaptobenzothiazole, sodium hydroxide, glycol, sodium dodecyl benzene sulfonate, D-sodium erythorbate, tributyl phosphate and deionized water; the cleaning agent B consists of ethylene diamine tetraacetic acid, ammonia water, imidazoline quaternary ammonium salt, hydrazine hydrate, tributyl phosphate and deionized water. Meanwhile, the invention also discloses the use of the cleaning agent in the chemical cleaning of boilers in power plants, wherein the scale sample contains apatite or/and calcium phosphate scale and the system contains austenitic steel, and the cleaning agent comprises the following steps: (1) cleaning by using a cleaning agent A; (2) and cleaning by using a cleaning agent B. After cleaning, intergranular corrosion to austenitic steel can not be generated, the cleaning effect to apatite and calcium phosphate scale is good, cleaning passivation can be completed through two-step cleaning, and the formed passivation film has good protection performance.)

1. A cleaning agent for scale-like apatite or/and calcium phosphate scale and system containing austenitic steel, which is characterized in that: consists of a cleaning agent A and a cleaning agent B,

the cleaning agent A comprises the following raw materials in percentage by weight based on 100 percent by weight:

3.00 to 6.00 percent of citric acid

0.75 to 1.50 percent of ammonia water

0.05 to 0.09 percent of 2-mercaptobenzothiazole

0.02 to 0.04 percent of sodium hydroxide

0.20 to 0.40 percent of glycol

0.01 to 0.03 percent of sodium dodecyl benzene sulfonate

0.10 to 0.30 percent of D-sodium erythorbate

0.02 to 0.10 percent of tributyl phosphate

The balance of deionized water;

the cleaning agent B comprises the following raw materials in percentage by weight based on 100 percent by weight:

2.00 to 3.00 percent of ethylenediamine tetraacetic acid

0.50 to 0.75 percent of ammonia water

Imidazoline quaternary ammonium salt 0.03% -0.06%

0.10 to 0.20 percent of hydrazine hydrate

0.02 to 0.10 percent of tributyl phosphate

The balance of deionized water.

2. The use of the cleaning agent according to claim 1, wherein: the application is that the cleaning agent is used for chemical cleaning of boilers in power plants, wherein scale samples contain apatite or/and calcium phosphate scale, and systems contain austenitic steel, and the method comprises the following steps:

(1) cleaning by using a cleaning agent A:

(11) putting a part of deionized water in the cleaning agent A in a dispensing box, adding sodium hydroxide into the dispensing box, then sequentially adding 2-mercaptobenzothiazole, sodium dodecyl benzene sulfonate and ethylene glycol, and uniformly stirring to form an A1 solution;

(12) injecting the residual deionized water in the cleaning agent A into the boiler system, starting a cleaning pump to circulate, starting a heater, adding an A1 solution when heating to 85 ℃, adding citric acid after uniform circulation, adding ammonia water after dissolution, adjusting the pH of the system to 3.5-4.0, and then adding tributyl phosphate; controlling the temperature of the cleaning system to be 90 +/-5 ℃, and circularly cleaning;

(13) detecting and analyzing the concentration of citric acid and Fe in the cleaning liquid in the boiler at fixed intervals³⁺Concentration, total iron ion concentration, when Fe is detected³⁺Concentration of>When the concentration is 300mg/L, adding D-sodium erythorbate into the boiler system, and continuously and circularly cleaning; when the concentration change of the total iron ions detected in the two previous and next steps is not more than 100 mg/L and the concentration change of the citric acid is not more than 0.1wt%, continuously and circularly cleaning for 1h, discharging the cleaning agent A, and finishing the first-step cleaning;

(2) cleaning by using a cleaning agent B:

(21) washing the boiler system by using deionized water, discharging while washing the boiler system by using water until the pH value of the washing water is more than 5, and discharging the washing liquid; then adding deionized water in the cleaning agent B into the boiler system, starting a cleaning pump to circulate, starting a heater, when the temperature is heated to 85 ℃, sequentially adding imidazoline quaternary ammonium salt, ammonia water, ethylene diamine tetraacetic acid and hydrazine hydrate, adjusting the pH value of the system to 9.5-10.0, and then adding tributyl phosphate; controlling the temperature of the cleaning system to be 90-120 ℃, and circularly cleaning;

(22) detecting and analyzing the concentration of the ethylene diamine tetraacetic acid and the concentration of total iron ions in the cleaning liquid in the boiler at fixed intervals, when the total iron ions detected at the previous and subsequent times do not exceed 100 mg/L and the change of the ethylene diamine tetraacetic acid does not exceed 0.1wt%, continuing to circularly clean for 1h, discharging the cleaning agent B, naturally ventilating and drying the boiler, and forming a complete and compact passive film on the inner surface of the boiler to finish cleaning.

3. Use according to claim 2, characterized in that: in the step (13) and the step (22), every fixed time is 1 h.

4. Use according to claim 2 or 3, characterized in that: the boiler is a drum furnace or a direct current furnace.

Technical Field

The invention belongs to the technical field of chemical cleaning of equipment in the electric power or chemical industry, and particularly relates to a cleaning agent for a scale sample containing apatite or/and calcium phosphate scale and a system containing austenitic steel and a chemical cleaning process for a power plant boiler.

Background

The heating power equipment boiler of the thermal power plant inevitably causes scaling of the heating surface of the boiler when running for a certain time in a high-temperature high-pressure water vapor environment, and when the scaling amount reaches a certain degree, the heat transfer efficiency of the boiler is affected, the quality of steam and water is deteriorated, so that the problems of coal consumption rise, corrosion of the heating surface and the like are caused, and the occurrence of boiler tube explosion accidents is seriously caused. In order to keep the inner surface of the heating surface clean, improve the quality of steam and water, prevent the occurrence of pipe explosion accidents caused by scaling and corrosion of the heating surface and ensure the safe and economic operation of a unit, the most effective solution is to adopt the chemical cleaning measure of the thermal equipment.

The chemical cleaning guideline for boilers in thermal power plants DL/T794-2012 stipulates the cleaning conditions and the ages of boilers with different pressure grades, and also lists different chemical cleaning processes. Generally, for steam drum furnaces of carbon steel and low alloy steel, the cleaning process which adopts hydrochloric acid as a main medium is the most economical and has the best effect; for a drum furnace and a direct current furnace containing austenitic steel, a furnace containing F such as hydrochloric acid or hydrofluoric acid cannot be used^-、Cl^-And the like, and the ionic medium sensitive to the austenitic steel material is cleaned by organic acid or organic composite acid such as citric acid, formic acid, glycolic acid, ethylene diamine tetraacetic acid and the like, so that intergranular corrosion on the austenitic steel is avoided, and the stress of a heated surface of a boiler is not influenced.

Subcritical unit boilers generally contain austenitic steel, so that organic acid or organic composite acid is required to be adopted for chemical cleaning. The components of scaling and corrosion products of the subcritical unit boiler mainly comprise iron oxides, namely ferroferric oxide and ferric oxide, and a small amount of other metal oxides, but for the subcritical unit boiler with calcium and magnesium ions contained in steam water for a long time due to leakage of a condenser in the operation process and phosphate treatment adopted for boiler water treatment, high-content calcium phosphates (Ca) are inevitably generated on the heating surface of the boiler₃(PO₄)₂) And apatite scale of which molecular formula is Ca₅(PO₄)₃F, the two substances are both insoluble in water and have low solubility, and through different organic acid cleaning process experiments, the apatite scale cannot be completely cleaned by one-step cleaning with single organic acid.

Therefore, in the technical field of boiler cleaning in power plants, the method for cleaning apatite or/and calcium phosphate scale of austenitic steel in a cleaning system and the cleaning method thereof have important significance.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a cleaning agent which is used for cleaning scale samples containing apatite or/and calcium phosphate scale and a system containing austenitic steel and application thereof, wherein the cleaning agent can clean the apatite or/and calcium phosphate, ferric oxide and other components in the system and does not generate intergranular corrosion on the austenitic steel.

A cleaning agent for scale containing apatite or/and calcium phosphate scale and system containing austenitic steel is composed of cleaning agent A and cleaning agent B,

the cleaning agent A comprises the following raw materials in percentage by weight based on 100 percent by weight:

3.00 to 6.00 percent of citric acid

0.75 to 1.50 percent of ammonia water

0.05 to 0.09 percent of 2-mercaptobenzothiazole

0.02 to 0.04 percent of sodium hydroxide

0.20 to 0.40 percent of glycol

0.01 to 0.03 percent of sodium dodecyl benzene sulfonate

0.10 to 0.30 percent of D-sodium erythorbate

0.02 to 0.10 percent of tributyl phosphate

The balance of deionized water;

the cleaning agent B comprises the following raw materials in percentage by weight based on 100 percent by weight:

2.00 to 3.00 percent of ethylenediamine tetraacetic acid

0.50 to 0.75 percent of ammonia water

Imidazoline quaternary ammonium salt 0.03% -0.06%

0.10 to 0.20 percent of hydrazine hydrate

0.02 to 0.10 percent of tributyl phosphate

The balance of deionized water.

The cleaning agent is applied to chemical cleaning of boilers in power plants, wherein scales in power plants contain apatite or/and calcium phosphate scales, and systems contain austenitic steel, and comprises the following steps:

(1) cleaning by using a cleaning agent A:

(11) putting a part of deionized water in the cleaning agent A in a dispensing box, adding sodium hydroxide into the dispensing box, then sequentially adding 2-mercaptobenzothiazole, sodium dodecyl benzene sulfonate and ethylene glycol, and uniformly stirring to form an A1 solution;

(12) injecting the residual deionized water in the cleaning agent A into the boiler system, starting a cleaning pump to circulate, starting a heater, adding an A1 solution when heating to 85 ℃, adding citric acid after uniform circulation, adding ammonia water after dissolution, adjusting the pH of the system to 3.5-4.0, and then adding tributyl phosphate; controlling the temperature of the cleaning system to be 90 +/-5 ℃, and circularly cleaning;

(13) detecting and analyzing the concentration of citric acid and Fe in the cleaning liquid in the boiler at fixed intervals³⁺Concentration, total iron ion concentration, when Fe is detected³⁺Concentration of>When the concentration is 300mg/L, adding D-sodium erythorbate into the boiler system, and continuously and circularly cleaning; when the concentration change of the total iron ions detected in the two previous and next steps is not more than 100 mg/L and the concentration change of the citric acid is not more than 0.1wt%, continuously and circularly cleaning for 1h, discharging the cleaning agent A, and finishing the first-step cleaning;

(2) cleaning by using a cleaning agent B:

(21) washing the boiler system by using deionized water, discharging while washing the boiler system by using water until the pH value of the washing water is more than 5, and discharging the washing liquid; then adding deionized water in the cleaning agent B into the boiler system, starting a cleaning pump to circulate, starting a heater, when the temperature is heated to 85 ℃, sequentially adding imidazoline quaternary ammonium salt, ammonia water, ethylene diamine tetraacetic acid and hydrazine hydrate, adjusting the pH value of the system to 9.5-10.0, and then adding tributyl phosphate; controlling the temperature of the cleaning system to be 90-120 ℃, and circularly cleaning;

(22) detecting and analyzing the concentration of the ethylene diamine tetraacetic acid and the concentration of total iron ions in the cleaning liquid in the boiler at fixed intervals, when the total iron ions detected at the previous and subsequent times do not exceed 100 mg/L and the change of the ethylene diamine tetraacetic acid does not exceed 0.1wt%, continuing to circularly clean for 1h, discharging the cleaning agent B, naturally ventilating and drying the boiler, and forming a complete and compact passive film on the inner surface of the boiler to finish cleaning.

Preferably, step (13) and step (22) are performed every 1h at fixed time intervals.

Preferably, the power plant boiler is a drum furnace or a once-through furnace.

The cleaning agent disclosed by the invention has the advantages that the raw materials of all the formulas exist independently, and are prepared in the application process. The addition amount of the cleaning agent A and the cleaning agent B is matched with the water volume of the boiler system.

The cleaning agent provided by the invention is used for cleaning scale which contains austenitic steel in a boiler system and contains apatite or/and calcium phosphate in a scale sample.

The invention has the advantages that:

the cleaning agent provided by the invention does not contain F^-、Cl^-Ions sensitive to the austenitic steel material are not subjected to intergranular corrosion, the cleaning effect on apatite and calcium phosphate scale is good, economic and reasonable, the cleaning time is short, cleaning passivation can be completed through two-step cleaning, and the labor intensity of field operators is reduced; the formed passive film has better protective performance, greatly shortens the water washing time in the starting stage of the boiler, and has faster qualified water vapor quality.

Drawings

FIG. 1 photographs before and after washing.

Detailed Description