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Acid-cleaning inhibiter for cleaning boiler and use method thereof

A pickling corrosion inhibitor and boiler cleaning technology, which is applied in the direction of boiler cleaning equipment, etc., can solve the problems of inconvenient application on site, excessive foam, and affecting the pickling process, etc., and achieve the effects of easy source, simple preparation method, and convenient use and operation

Active Publication Date: 2011-03-30
湖南省湘电试验研究院有限公司 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, IS-129, a commonly used corrosion inhibitor for hydrochloric acid pickling, has high corrosion inhibition efficiency and moderate toxicity, but there are many foams, which will affect the pickling process in severe cases.
[0004] In addition, sulfamic acid, nitric acid, hydrofluoric acid, phosphoric acid and sulfuric acid are also used in the chemical cleaning of large-scale thermal power plants, especially the pre-furnace systems of some infrastructure units are usually cleaned with citric acid, while the boiler body is often cleaned with hydrochloric acid Cleaning, in the current situation, two different corrosion inhibitors are required, which brings inconvenience to field application

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The pickling corrosion inhibitor used for boiler cleaning of the present invention adopts the formula of the following mass percentages:

[0029] Hydrochloric acid 3.0%, methenamine 0.08%, xylene thiourea or thiourea 0.04%, thiocyanate 0.05%, dodecyl-hexadecyl benzyl chloride or bromide 0.12%, surfactant 0.12% , the balance is water, and the surfactant is dodecyl dihydroxyethyl betaine.

Embodiment 2

[0031] The pickling corrosion inhibitor used for boiler cleaning of the present invention adopts the formula of the following mass percentages:

[0032] Hydrochloric acid 8.0%, methenamine 0.25%, xylene thiourea or thiourea 0.15%, thiocyanate 0.01%, dodecyl-hexadecyl benzyl chloride or bromide 0.03%, surfactant 0.05% , the balance is water, and the surfactant is dodecyl dihydroxyethyl betaine.

Embodiment 3

[0034] The pickling corrosion inhibitor used for boiler cleaning of the present invention adopts the formula of the following mass percentages:

[0035] Hydrochloric acid 5.0%, methenamine 0.16%, xylene thiourea or thiourea 0.10%, thiocyanate 0.03%, dodecyl-hexadecyl benzyl chloride or bromide 0.08%, surfactant 0.09% , the balance is water, and the surfactant is lauryl betaine.

[0036] The using method of above-mentioned each hydrochloric acid pickling corrosion inhibitor comprises the following steps:

[0037] (1) Connect the boiler cleaning system, adjust the water pressure of the boiler to meet the requirements, isolate the system irrelevant to cleaning, including the valves connected to the equipment and pipelines within the cleaning range, which must be closed tightly, and the devices in the steam drum that are not suitable for cleaning, such as cyclone separators, It must be dismantled, and the water level gauge and all instruments, sampling, dosing and other pipelines...

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PUM

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Abstract

The invention discloses an acid-cleaning inhibiter for cleaning a boiler and a use method thereof. The acid-cleaning inhibiter comprises the following components by weight percent: 2.0%-10.0% of acid liquor, 0.08-0.25% of urotropine, 0.04-0.15% of dimethylbenzene thiourea or thiourea, 0.01-0.05% of thiocyanate, 0.03-0.12% of dodecyl-cetyl phenmethyl chloride or bromide, 0.05-0.12% of a surface active agent and the balance of water. Acids suitable for the acid-cleaning inhibiter include hydrochloric acid, citric acid, sulphuric acid, hydrofluoric acid, aminosulfonic acid and phosphoric acid, which are suitable for boiler steel, mild steel, alloy steel and steam steel. The inhibition effect of the invention is over 98% with less toxicity under the boiler chemical cleaning condition, the value of LD50 (orally taken by mice) is 5.74 g / kg. The invention can be stored for 2 years, resistant Fe<3+> ion is 800 mg / kg in the acid cleaning. The preparation method has simple steps, easily obtained raw materials and convention operation.

Description

technical field [0001] The invention belongs to chemical preparations and methods for boiler cleaning, in particular to a pickling corrosion inhibitor for boiler cleaning and a use method thereof. Background technique [0002] In recent years, citric acid pickling corrosion inhibitor is a special corrosion inhibitor urgently needed in the chemical cleaning of large thermal power plants. Shaanxi Chemical Industry Design Institute in China made SH-405 citric acid pickling corrosion inhibitor by using pyrazolone drug by-product FAA colloid, etc. The performance is not stable enough, the shelf life is short, and it has a strong pungent smell. The Lan-826 corrosion inhibitor commonly used in China has precipitated after storage, the corrosion inhibition efficiency has decreased, and its toxicity is relatively high, LD 50 (Mice orally): 1130mg / kg. [0003] Hydrochloric acid has a strong ability to dissolve iron oxides. After pickling, the surface is in good condition without res...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F22B37/52C23G1/06
Inventor 张玉福冯兵许文
Owner 湖南省湘电试验研究院有限公司