EDTA (Ethylene Diamine Tetraacetic Acid) low-temperature cleaning aid and application thereof

A cleaning aid and low-temperature technology, applied in the coating process of metal materials, etc., to achieve the effects of reduced corrosion speed, simple process, and flexible heating methods

Active Publication Date: 2012-03-07
兰州陇能电力科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The present invention aims to solve the technical problem that the traditional EDTA cleaning process can only be carried out at 135-140°C, and provides an EDTA low-temperature cleaning aid and its application

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The production steps of EDTA low temperature cleaning aid are as follows:

[0021] 1. Inject 350 kg of water into the reactor;

[0022] 2. Under continuous stirring, add 450 kg of nonylphenol polyoxyethylene ether to 350 kg of desalinated water, and continue stirring until uniformly mixed;

[0023] 3. Under continuous stirring, add 200 kg of octylphenol polyoxyethylene ether to the mixed solution prepared in the second step, and stir evenly to obtain EDTA low-temperature cleaning aid.

[0024] Wherein, nonylphenol polyoxyethylene ether is commercially available NP-10, its degree of polymerization is 10, HLB value 14;

[0025] Octylphenol polyoxyethylene ether is commercially available OP-10, its degree of polymerization is 10, HLB value 14.

Embodiment 2

[0027] The EDTA low-temperature cleaning aid prepared in Example 1 was applied to a 300MW infrastructure unit, and the scope of cleaning was: the water supply system in front of the furnace, the economizer system, and the boiler body system. Use cycle cleaning. The chemical cleaning system is designed as follows: cleaning tank→cleaning pump→temporary pipeline→low pressure water supply pipeline at the outlet of condensate pump→shaft seal heater→low pressure heater→deaerator inlet pipe→temporary bypass pipe→deaerator downpipe→ Feed water pump inlet pipe → temporary bypass pipe → feed water pump outlet pipe → high pressure heater → economizer → steam drum → surrounding water cooling wall → surrounding water cooling wall lower header → temporary pipeline → temporary liquid return main pipe → liquid return valve → cleaning box.

[0028] EDTA cleaning solution: 1.0-1.5% EDTA low-temperature cleaning aid, 3-5% EDTA disodium salt (i.e. Na 2 EDTA), 0.3-0.5% corrosion inhibitor IS-136...

Embodiment 3

[0030] The EDTA low-temperature cleaning aid prepared in Example 1 was applied to the boiler body of the 660MW infrastructure unit. The scope of cleaning is: high heating system, economizer, water wall system, start separator. The chemical cleaning circuit system is designed as: cleaning tank→cleaning pump→temporary pipeline→high pressure water supply chemical cleaning interface→high pressure heater→main water supply pipeline→coal economizer→water wall→start separator→temporary interface for chemical cleaning before atmospheric expansion →Temporary pipeline→Liquid return door→Cleaning tank.

[0031] EDTA cleaning solution: 1.0-1.5% EDTA low-temperature cleaning aid, 3-5% EDTA disodium salt, 0.3-0.5% corrosion inhibitor SH-255, 0.03% MBT, 0.15-0.2% hydrazine, The rest is water. Start the heating system at the bottom of the boiler, the steam heating system of the cleaning box, and the heating system of the high-pressure heater to heat the cleaning liquid to 75-85°C, and the cl...

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Abstract

The invention belongs to the field of chemical cleaning of boilers, and provides an aid for reducing chemical cleaning temperature of EDTA (Ethylene Diamine Tetraacetic Acid) and application of the aid. The EDTA low-temperature cleaning aid comprises the following components in percent by weight: 43-47 percent of nonylphenol polyethylene glycol ether, 18-22 percent of octylphenol polyoxyethylene ether and the balance of water, wherein the polymerization degree of the nonylphenol polyethylene glycol ether is 9-11, and the polymerization degree of the octylphenol polyoxyethylene ether is 9-11. After 1-1.5 percent of EDTA low-temperature cleaning aid provided by the invention is added to an EDTA cleaning solution, the cleaning temperature is reduced to 75-85 DEG C from 135-140 DEG C of the traditional process, so that the heating more is more flexible and heating is more uniform, and the average corrosion speed is reduced by 50 percent. The EDTA low-temperature cleaning aid provided by the invention is simple, convenient and safe in process.

Description

technical field [0001] The invention belongs to the field of chemical cleaning of boilers, and in particular relates to an auxiliary agent for reducing the temperature of EDTA chemical cleaning and its application. Background technique [0002] According to the requirements of "Guidelines for Chemical Cleaning of Boilers in Thermal Power Plants" (DL / T 794-2001), the boiler body, economizer, and water supply system in front of the furnace should be chemically cleaned separately for infrastructure and operating units. Among them, for the boiler body and economizer system, the cleaning process of inorganic acids such as hydrochloric acid, hydrofluoric acid and sulfuric acid and the cleaning process of organic acids such as sulfamic acid, EDTA and glycolic acid are generally used, and citric acid is generally used for the water supply system in front of the furnace. Organic acid cleaning process. [0003] The EDTA cleaning process should be used for new units that are mainly en...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23G1/00C23C22/62
Inventor 张振达张福祥李兴德
Owner 兰州陇能电力科技有限公司
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