Corrosion inhibition method for non-passive metal and boiler

A corrosion-inhibiting, metal-body technology, applied in corrosion-reducing boiler components, chemical instruments and methods, boiler cleaning devices, etc., capable of solving problems such as corrosion and damage of heat transfer tubes

Inactive Publication Date: 2003-05-21
MIURA COMPANY LIMITED
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] However, when once-through boilers are operated in accordance with the boiler water management standards recommended in JIS B 8223: 1999, and the progress of corrosion of heat transfer tubes is evaluated based on the above indicators, even heat transfer tubes that can be judged to be in contact with boiler water When the corrosion condition does not reach damage, sometimes this part of the heat transfer tube will be accidentally damaged due to corrosion

Method used

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  • Corrosion inhibition method for non-passive metal and boiler
  • Corrosion inhibition method for non-passive metal and boiler
  • Corrosion inhibition method for non-passive metal and boiler

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Embodiment

[0049] While supplying feed water with different concentrations of citric acid, it was operated to supply the boiler manufactured by the patent applicant company. At this time, adjust the concentration ratio of boiler water so that: the M alkalinity (acid consumption (PH4.8)) of boiler water is 300mg CaCO 3 / l, chloride ion concentration 200mg / l, sulfate ion concentration 400mg / l, dissolved oxygen concentration 4.0ppm and citric acid concentration 70mg / l. The pH of the boiler water is adjusted to 11.5% by properly injecting an aqueous sodium hydroxide solution into the feed water. The operating conditions of the boiler are set as follows: the operating time is 48 hours, the operating pressure is 0.29MPa and the feed water temperature is 50°C.

[0050] The relationship between the concentration of citric acid in the boiler water and the maximum depth of corrosion pits (μm) generated in the heat transfer tubes was investigated for boilers operated under the above conditions. T...

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Abstract

To suppress corrosion causing in a nonpassivated metallic body such as a heat transfer pipe of a boiler by the influence of water. The method of suppressing corrosion includes a stage where the concentration of citric acid contained in water influencing on a nonpassivated metallic body such as a heat transfer pipe of a boiler is set in at least 50 mg / l. Suppressible corrosion by this method is, e.g. local corrosion occurring in the thickness direction of a nonpassivated metallic body.

Description

[technical field] [0001] The invention relates to a method for inhibiting corrosion, in particular to a method for inhibiting corrosion on non-passivated metal bodies such as boiler heat transfer tubes due to the influence of moisture. [Background technique] [0002] Once-through boilers that fall under the category of special circulation boilers specified in Japanese Industrial Standards (JIS) are equipped with heat transfer tubes that heat feed water to generate steam. This type of heat transfer tube is made of carbon steel and other non-passive metals, so the parts in contact with the boiler water are corroded and damaged by the boiler water, which often has a fatal impact on the life of the once-through boiler. For this reason, in order to make the once-through boiler run stably for a long time, it is necessary to effectively suppress the corrosion of the heat transfer tube. [0003] Therefore, JIS B 8223:1999 sets various management items concerning the water quality o...

Claims

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Application Information

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IPC IPC(8): F22B37/52C02F5/10C23F11/04C23F11/12F22D11/00F28F19/00
CPCC23F11/124F22B37/025
Inventor 中岛纯一野上康雄加藤润一米加田勇
Owner MIURA COMPANY LIMITED
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