Compound boiler scale and corrosion inhibitor as well as preparation method and application of thereof

A scale and corrosion inhibitor, a composite technology, applied in descaling and water softening, chemical instruments and methods, special treatment targets, etc., can solve the scaling and pipeline corrosion of steam turbines in steam systems, and the limited pH buffering capacity of boiler water , shortening the service life of boilers, etc., to achieve excellent scale inhibition, increase critical salt content, and delay metal corrosion.

Active Publication Date: 2017-09-19
SHENYANG DREAMLAND ENVIRONMENTS TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are many technical problems in ordinary acid cleaning boilers: firstly, the acid is highly corrosive, which shortens the service life of the boiler; secondly, the amount of acid is not easy to control, and the amount of acid can not only remove the scale on the inner wall of the boiler, but also cause corrosion on the boiler wall; Thirdly, acid can only remove the scale of specific components, it is ineffective for insoluble scale, and the removal efficiency is low
[0004] At present, the boiler water system is treated with trisodium phosphate, which has obvious treatment shortcomings due to its own properties: (1) PO 4 3- There is no low-dose (threshold) effect on scale inhibition, so it has no inhibitory effect on scale and can only generate Ca 10 (OH) 2 (PO 4 ) 6 Water slag, which is formed according to stoichiometry, has a large amount of sewage, otherwise there will inevitably be supersaturated deposition of phosphate in the furnace, which will increase the tendency of entrainment; (2) PO 4 3- It is a scale-forming group, which cannot provide effective passivation protection for boilers under high temperature and high pressure, because the combined iron phosphate salt is the corrosive ion Fe 3+ Formed; (3) PO 4 3- The pH buffering capacity of the boiler water is limited, and the "temporary disappearance" of phosphate is prone to occur when the boiler load changes, resulting in excessive addition of sodium phosphate; (4) The generated salts are easily entrained into the steam system, causing steam Fouling of system turbines and corrosion of pipelines
However, aminotrimethylene phosphonic acid is used in this invention. During use, organic phosphine will increase the amount of pollutant discharge, which is not conducive to environmental protection.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Composite boiler scale and corrosion inhibitor, including by weight percentage: polyaspartic acid 10%, carbohydrazide 5%, carboxylic acid-sulfonate copolymer 7%, alkanolamine 12% and water 66%, The molecular weight of the polyaspartic acid is 4000.

[0038] The preparation process of the above composite boiler scale and corrosion inhibitor is as follows: first add 660kg of water to the reactor, heat the water temperature to 20°C, add 100kg of polyaspartic acid, 70kg of carboxylic acid-sulfonate copolymer and alkanolamine 120kg, stirred for 8 minutes, then added 50kg of carbohydrazide, stirred for 60 minutes, left to cool, and the composite boiler scale and corrosion inhibitor was obtained.

[0039] The obtained composite boiler scale and corrosion inhibitor was applied to the power boiler device of a chemical fertilizer factory, the steam generation was 400 tons / h, the boiler feed water was filtered and ion exchanged for primary desalination, pH6.5, conductivity 0.4 μs...

Embodiment 2

[0042]Composite boiler scale and corrosion inhibitor, including by weight percentage: polymethacrylic acid 2%, carbohydrazide 10%, carboxylic acid-sulfonic acid-nonionic terpolymer 12%, alkanolamine 5% and water 71%, the molecular weight of the polymethacrylic acid is 15000.

[0043] The preparation process of the above composite boiler scale and corrosion inhibitor is as follows: first add 710kg of water to the reactor, heat the water temperature to 25°C, add 20kg of polymethacrylic acid, 120kg of carboxylic acid-sulfonic acid-nonionic terpolymer and alkane 50 kg of alkanolamine, stirred for 20 minutes, then 100 kg of carbohydrazide was added, stirred for 30 minutes, left to cool, and the composite boiler scale and corrosion inhibitor was obtained.

[0044] The obtained composite boiler scale and corrosion inhibitor was applied to the high-pressure boiler device of the thermal power plant, with a steam generation of 400 tons / h, and the boiler feed water was filtered, ion-exch...

Embodiment 3

[0047] Composite boiler scale and corrosion inhibitor, including by weight percentage: 15% of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid copolymer, 3% of acetaldehyde oxime, 2% of carboxylic acid-sulfonate copolymer, Cycloalkanolamine 2% and water 69%.

[0048] The preparation process of the above composite boiler scale and corrosion inhibitor is as follows: first add 690kg of water to the reactor, heat the water to 22°C, add 15kg of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid copolymer, carboxylic acid- 20kg of sulfonate copolymer and 20kg of alkanolamine were stirred for 15 minutes, then 30kg of acetaldehyde oxime was added, stirred for 30 minutes, left to cool, and the composite boiler scale and corrosion inhibitor was obtained.

[0049] The obtained composite boiler scale and corrosion inhibitor was applied to a medium-pressure boiler device in a plastic factory, with a steam generation of 150 tons / h, and the boiler feed water was filtered, i...

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Abstract

The invention provides an organic polymer scale inhibitor in a compound boiler scale and corrosion inhibitor. Particularly, poly(aspartic acid) has a good scale inhibition function on calcium carbonate and magnesium hydrate and has good biodegradability, no impurities are introduced into a boiler system, the clinical salt content of boiler water is increased, and the boiler blowdown rate is reduced; an organic polymer dispersant has a dispersion function and can stabilize calcium and magnesium ions in water and inhibit formation of silica scale, ferric scale, cooper scale and magnesium scale; the corrosion inhibitor has very high reductivity, a black Fe3O4 passivation film can be formed on the surface of the inner wall of a boiler, and the boiler is prevented from being further corroded. According to the compound boiler scale and corrosion inhibitor, negative influences of trisodium phosphate are eliminated, the discharge capacity is effectively reduced, and environment burden is reduced. A water treatment agent is applied to low-pressure, medium-pressure and high-pressure boilers by adjusting the pH value, inhibiting scaling and preventing corrosion, pH of boiler water is effectively buffered, the hydrogen brittleness phenomenon caused by excessive acid and alkali in the boiler is prevented, and boiler metal is protected.

Description

technical field [0001] The invention belongs to the field of chemical industry and water treatment, and in particular relates to a composite boiler scale and corrosion inhibitor, its preparation method and application. Background technique [0002] After the boiler has been in operation for a long time, scale and rust will inevitably appear on the inner wall of the boiler. After the boiler is scaled, the heat transfer performance of the heating surface is deteriorated, the heat released by the fuel combustion cannot be transferred to the boiler water in time, and a large amount of heat is taken away by the flue gas, causing the exhaust gas temperature to be too high and the loss of the exhaust gas to increase. Boiler thermal efficiency decreases and boiler fuel usage increases. A scaled boiler can easily cause overheating, deformation, bulging or even explosion on the heat transfer surface of the boiler during use. Scale containing high-priced iron can easily cause corrosi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F5/12
CPCC02F5/12C02F2303/08C02F2303/22
Inventor 沈红新
Owner SHENYANG DREAMLAND ENVIRONMENTS TECH
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