CN101798687A - Environment friendly gas phase corrosion inhibitor used for direct air cooling system - Google Patents

Abstract

The invention discloses an environment-friendly gas-phase corrosion inhibitor for direct air-cooling system, which is composed of the following raw materials in weight percentage: 30%-40% of organic amine, 20%-30% of inorganic ammonium, and 20%-30% of sodium benzoate %, D-isoascorbate sodium 10% to 20%. The organic amine is hexamethylenetetramine, thiourea or carbonamide, and the inorganic ammonium is diammonium hydrogen phosphate, ammonium bicarbonate or ammonium carbonate. Sodium benzoate is usually used in food preservatives; diammonium hydrogen phosphate is used in medicine, feed additives, etc.; D-sodium erythorbate is a new type of biological food anti-oxidation, anti-corrosion and fresh-keeping color aid; the toxicity of the remaining ingredients is extremely low or non-toxic. It is harmless to the environment and human body, has the advantages of convenient production, use, environmental friendliness, high corrosion inhibition efficiency and long-lasting effect, and can effectively prevent corrosion of direct air cooling systems.

Description

Environmentally friendly gas phase corrosion inhibitor for direct air cooling system

technical field

The invention belongs to the production technical field of anticorrosion preparations, and relates to an environment-friendly gas phase corrosion inhibitor used to prevent direct air cooling systems of thermal power plants.

Background technique

Coal resources are abundant in northern my country, but water resources are relatively scarce, which is suitable for the promotion and application of direct air-cooled thermal power generating units. Practice has shown that after the direct air cooling system is out of service, the internal water vapor will severely corrode the steel material on the inner surface of the air cooling tower. After the unit is started, before and after hot flushing and flushing, the condensed water turns red and yellow, and the iron ion content can reach up to about 600-800ug/L, resulting in prolonged flushing time and greater loss of fuel and desalted water.

Vapor phase inhibitor (Vapor phase inhibitor, VCI), also known as volatile corrosion inhibitor (volatile corrosion inhibitor, VCI) or vapor phase rust inhibitor. In the process of metal use, only a small amount of this substance needs to be added, relying on the effect of its volatilized corrosion inhibitor molecules or corrosion inhibitor groups on the metal surface, the metal can be protected from atmospheric corrosion or the corrosion rate can be reduced. It is widely used in Corrosion protection of metals. Vapor-phase corrosion inhibitors can be used to prevent corrosion in direct air cooling systems. However, although the commonly used gas-phase corrosion inhibitors have excellent corrosion inhibition performance, most of them have high toxicity, which seriously affects the health of operators and pollutes the environment. .

The most commonly used gas-phase corrosion inhibitor cyclohexylamine nitrite has been proved to be a highly toxic substance; the patent No. CN1537179A discloses a gas-phase corrosion inhibitor containing 0.1-40% of nitrite, and nitrite has Carcinogenic effect; Invention patent (ZL200310101610.2) discloses a gas-phase corrosion inhibitor for industrial equipment protection, which contains cyclohexylamine or morpholine, which are highly toxic.

The above-mentioned corrosion inhibitors are difficult to popularize due to strong harm to the human body and are strongly resisted by users. Therefore, it is necessary to develop an environment-friendly gas-phase corrosion inhibitor, which can meet the needs of anti-corrosion without causing harm to the health of operators.

Contents of the invention

The purpose of the present invention is to provide a gas-phase corrosion inhibitor for direct air cooling systems with reasonable composition, convenient production and use, environmental friendliness and long-lasting effect.

In order to achieve the above purpose, the technical solution of the present invention is to select non-toxic or low-toxic substances to the human body and configure them in consideration of the synergistic effect of the anti-corrosion microcosmic mechanism between the components. It consists of the material raw materials in the following weight percentages:

Organic amine 30%～40%,

Inorganic ammonium 20%～30%,

Sodium Benzoate 20%～30%,

Sodium D-isoascorbate 10% to 20%.

Among the raw material components of the above materials, the organic amine is hexamethylenetetramine, thiourea or carbonamide, and the inorganic ammonium is diammonium hydrogen phosphate, ammonium bicarbonate or ammonium carbonate. Sodium benzoate is usually used in food preservatives; diammonium hydrogen phosphate is used in medicine, feed additives, etc.; D-sodium erythorbate is a new type of biological food anti-oxidation, anti-corrosion and fresh-keeping color aid; the toxicity of the remaining ingredients is extremely low or non-toxic.

The principle of action of the vapor phase corrosion inhibitor of the present invention is: organic amine and sodium benzoate can simultaneously form a hydrophobic film on the metal surface to isolate the oxidative gas and increase the pH value to realize anti-corrosion effect, which has a slow volatilization speed and long-lasting effect. The advantages of strong protection ability; inorganic ammonium salts are easy to decompose, which can quickly increase the alkalinity of the system and achieve the purpose of slowing down corrosion; D-sodium erythorbate can undergo redox reactions with oxygen in the system to reduce the oxygen concentration in the system; see the above Several substances have a synergistic effect with each other.

Compared with the existing similar technologies, the advantages of the present invention are: 1. The corrosion inhibitor adopts a green formula, has no harm to the environment, has the advantage of being environmentally friendly, and conforms to the development trend of corrosion inhibitors; 2. The corrosion inhibitor has High corrosion inhibition efficiency and long-lasting effect.

When in use, pipe valves are used to connect the protected direct air cooling system, the container with the corrosion inhibitor and the fan to form a closed cycle. Through air circulation, the corrosion inhibitor vapor is continuously carried into the direct air cooling system to achieve the purpose of preventing corrosion.

Detailed ways

Example 1:

Take 40 parts of hexamethylenetetramine, 20 parts of ammonium carbonate, 20 parts of sodium benzoate, and 20 parts of sodium D-isoascorbate, and mix them uniformly under dry conditions to form a gas phase corrosion inhibitor. The carbon steel test piece was placed in 10% sodium chloride vapor at 60°C for 209 hours, and the corrosion inhibition efficiency reached 93.97%.

Example 2:

Take 20 parts each of hexamethylenetetramine and thiourea; 15 parts each of diammonium hydrogen phosphate and ammonium carbonate, 10 parts of sodium benzoate, and 20 parts of sodium D-isoascorbate, and mix them uniformly under dry conditions to form a gas phase corrosion inhibitor. agent. The carbon steel test piece was placed in 10% sodium chloride vapor at 60°C for 209 hours, and the corrosion inhibition efficiency reached 90.71%.

Example 2:

Take 20 parts of hexamethylenetetramine, thiourea and carbonamide; 10 parts of ammonium carbonate, 10 parts of sodium benzoate, and 20 parts of D-sodium erythorbate, and mix them uniformly under dry conditions to form a gas phase corrosion inhibitor . The carbon steel test piece was placed in 10% sodium chloride vapor at 60°C for 209 hours, and the corrosion inhibition efficiency reached 97.07%.

Claims (3)

1. an environment-friendly gas-phase corrosion inhibitor for direct air-cooling system, it is characterized in that, it is made up of the material raw material of following percentage by weight: Organic amine 30%～40%, Inorganic ammonium 20%～30%, Sodium Benzoate 20%～30%, Sodium D-isoascorbate 10% to 20%. 2. The environment-friendly gas-phase corrosion inhibitor for direct air-cooling system according to claim 1, wherein said organic amine is hexamethylenetetramine, thiourea, carbonamide or cyclohexylamine nitrite. 3. The environment-friendly gas-phase corrosion inhibitor for direct air-cooling system according to claim 1, wherein said inorganic ammonium is diammonium hydrogen phosphate, ammonium bicarbonate or ammonium carbonate.