I. Industrial Valve Corrosion Background

Industrial valves are important components in industrial pipelines, used to control the flow of various media such as air, water, steam, various corrosive substances, slurry, oil, molten metals, and radioactive media. Valve corrosion is typically understood as the degradation of the valve's metallic materials due to chemical or electrochemical environmental factors. Metal corrosion has a significant impact on the valve's operational lifespan, reliability, and service life.

The combined effects of mechanical and corrosive factors greatly increase the overall wear on the contact surfaces. During operation, the valve's friction surfaces experience wear due to the simultaneous mechanical action and the chemical or electrochemical interaction between the metal and the environment, leading to wear and damage. For valves, the complexity of climatic conditions and the presence of hydrogen sulfide, carbon dioxide, and certain organic acids in media such as oil, natural gas, and oilfield water exacerbate the destructive impact on metal surfaces, causing them to lose their functionality quickly.

I. Reference Standards

Current national standards, relevant regulations, and mandatory standard provisions;

"Code for Construction and Acceptance of Building Anti-corrosion Engineering" (GB50212-2002)

"Standard for Corrosion and Rust Removal Levels of Steel Surface Before Coating" (GB8923-1988)

"Safety Regulations for Coating Operations and Safety Management Rules" (GB6514-1995)

"Quality Requirements for Anti-corrosion Coatings" (GB6514-1991)

"Safety Regulations for Coating Operations, Paint Process Safety, and Ventilation Purification" (DJ/T6931-1999)

"Code for Construction and Acceptance of Industrial Equipment and Pipeline Anti-corrosion Engineering" (HGJ229-91)

"Safety Regulations for Coating Operations and Safety of Surface Preparation Process" (GB7692-87)

"Noise Limits at Construction Sites" (GB12523-90)

ISO9001 Quality Management System Documents

ISO14001 Environmental Management System Documents

GB/T28001 Occupational Health and Safety Management System Documents

I. Design Basis

Environmental Conditions: The corrosion level of atmospheric environments on steel structures can be determined according to Table 1.

I. Butterfly Valve Corrosion Protection Scheme

Corrosion is a common problem encountered during the use of butterfly valves and is also a manifestation of valve material damage caused by environmental or other factors. Since the corrosion of butterfly valves is triggered by factors such as the environment, to achieve corrosion protection for the butterfly valve, measures must be taken from both the environment and the valve itself. In a butterfly valve, the valve body accounts for a significant proportion, making the corrosion of the valve more severe during the corrosion process. The causes of corrosion are generally divided into two types: chemical corrosion and electrochemical corrosion. The rate of these two types of corrosion depends on the temperature, pressure, and chemical properties of the corrosive medium in the environment, and partly on the inherent chemical properties of the valve body material. Therefore, DreamZinc Technology has developed a corrosion protection scheme using both water-based and oil-based coatings for the butterfly valve corrosion issue.

Table 1: Valve Inner Wall Corrosion Protection Scheme

I. Ball Valve External Corrosion Protection Scheme

Corrosion is a common issue encountered during the operation of ball valves. It is a form of damage caused by environmental or other factors affecting the valve materials. Since the corrosion of ball valves is triggered by external factors like the environment, and considering that the valve body occupies a large proportion of the valve, the degree of corrosion is typically significant. The causes of corrosion are generally divided into two types: chemical corrosion and electrochemical corrosion. The rate of corrosion for both types depends on factors such as environmental temperature, pressure, the chemical properties of the corrosive medium, and to some extent, the inherent chemical properties of the valve body materials. To address this, Mengneng Technology has developed a corrosion protection scheme using water-based and oil-based coatings for ball valves.

Oil-based Coating Corrosion Protection Scheme

Water-based Coating Corrosion Protection Scheme

1. Ball Valve Corrosion Protection Plan

Ball valves are widely used in industries such as oil refining, long-distance pipelines, chemicals, paper-making, pharmaceuticals, water, energy, municipalities, steelmaking, and more, playing a vital role in the national economy.

During the use of ball valves, corrosion issues often occur. Typically, corrosion of the valve body is understood as the damage to the metal caused by the chemical or electrochemical effects of the environment. Since the phenomenon of "corrosion" results from the spontaneous interaction between metal and the surrounding environment, the focus in corrosion prevention is on how to separate the metal from the environment or the use of more non-metallic composite materials.

Corrosion Protection Plan Using Oil-Based Coatings

Corrosion Protection Plan Using Water-Based Coatings

I. Corrosion Protection Plan for the Inner Wall of the Regulating Valve

A regulating valve, also known as a control valve, is the final control element in industrial automation process control. It adjusts process parameters such as flow rate, pressure, temperature, and liquid level by receiving control signals from the regulating control unit and using power operation. Since the regulating valve directly contacts the medium, it may experience corrosion or wear due to temperature, pressure, viscosity, solid particles, or corrosive media. The corrosion or wear can take many forms, with the valve plug and valve seat being particularly vulnerable to severe corrosion or wear due to high-speed scouring by the medium.

II. Oil-Based Coating Corrosion Protection Plan

III. Water-Based Coating Corrosion Protection Plan

I. Corrosion Protection Scheme for the Outer Wall of the Regulating Valve

The corrosion damage to metal has a significant impact on the service life, reliability, and longevity of the regulating valve. The mechanical and corrosive factors greatly increase the total wear on the contact surface of the valve. The total wear of the friction surface during the operation of the regulating valve. During operation, the friction surface experiences wear and damage due to simultaneous mechanical action as well as chemical or electrochemical interactions between the metal and the environment. For regulating valves, the climatic conditions of pipeline engineering are complex: the presence of hydrogen sulfide, carbon dioxide, and some organic acids in media such as oil, natural gas, and formation water increases the destructive power on the metal surface, thus quickly impairing its working ability.

Oil-Based Coating Corrosion Protection Scheme

Water-Based Coating Corrosion Protection Scheme

1. Gate Valve Internal Wall Corrosion Protection Plan

The gate valve has a gate as its closing element, with the movement direction of the gate perpendicular to the flow direction of the fluid. A gate valve can only be fully opened or fully closed, but not used for regulation or throttling. The gate has two sealing surfaces, and the most commonly used type has a wedge-shaped sealing surface, with the wedge angle varying according to the valve parameters, typically 5°, or 2°52' when the medium temperature is low. Corrosion of the gate valve is generally understood as the damage caused to the valve's metal materials due to chemical or electrochemical environments. Since corrosion occurs from the spontaneous interaction between the metal and the surrounding environment, the key to preventing corrosion is isolating the metal from the surrounding environment or using more non-metallic synthetic materials.

Oil-based Coating Corrosion Protection Plan

Water-based Coating Corrosion Protection Plan

1. Gate Valve Exterior Anti-Corrosion Plan

The corrosion of gate valves is usually understood as the damage caused to the valve's metal materials under chemical or electrochemical environmental effects. Since the chemical corrosion of metals depends on factors like temperature, mechanical load of friction parts, sulfur compounds in lubricants, their acid resistance stability, the duration of contact between metal and medium, the catalytic effect of metals on nitriding processes, and the molecular conversion speed of corrosive substances, DreamEnergy Technology has developed anti-corrosion plans using both water-based and oil-based coatings for gate valve corrosion.

Oil-Based Coating Anti-Corrosion Plan

Water-Based Coating Anti-Corrosion Plan

I. CORROSION PROTECTION FOR THE INNER WALL OF GATE VALVE

A gate valve is a forced-sealing valve primarily used to control the flow of water, air, steam, and various corrosive media, and it has a highly reliable shut-off function. The change in the valve seat opening is directly proportional to the valve disc travel, making it highly suitable for flow regulation. Corrosion of the gate valve manifests in two forms: chemical corrosion and electrochemical corrosion. The corrosion rate is determined by factors such as the medium's temperature, pressure, chemical properties, and the corrosion resistance of the valve body material.

Oil-Based Coating Corrosion Protection Plan

Water-Based Coating Corrosion Protection Plan

I. Anti-corrosion Protection for the Outer Surface of the Gate Valve

The corrosion of a gate valve is generally understood as the damage caused to the metal material of the valve, such as the V-type regulating ball valve, under the influence of chemical or electrochemical environments. Since the phenomenon of "corrosion" occurs due to the spontaneous interaction between metal and the surrounding environment, the focus of anti-corrosion protection is to isolate the metal from the surrounding environment or to use more non-metallic synthetic materials. The valve body (including the valve cover) accounts for most of the weight of the valve and is in constant contact with the medium, so the selection of the valve is often based on the material of the valve body.

Anti-corrosion Protection Using Oil-based Coatings

Anti-corrosion Protection Using Water-based Coatings

I. Check Valve Internal Wall Anti-Corrosion Plan

A check valve is a valve that opens and closes automatically depending on the flow of the medium, primarily used to prevent the reverse flow of the medium. It is also known as a non-return valve, one-way valve, reverse flow valve, and back pressure valve. The check valve is an automatic valve whose main function is to prevent backflow, prevent pump and motor reversal, and prevent the discharge of medium from the container.

Oil-based Coating Anti-Corrosion Plan

Water-based Coating Anti-Corrosion Plan

I. Check Valve Exterior Corrosion Protection Plan

The corrosion issue of check valves significantly affects the product's service life and can impact its performance. During operation, the valve's friction surfaces experience wear and damage due to mechanical action and chemical reactions. For the valve body, the complexity of the pipeline's working climate conditions, as well as the presence of hydrogen sulfide, certain organic acids in media like petroleum, natural gas, and oilfield water, increases the destructive power on the metal surface, causing it to quickly lose its operational capacity.

Oil-based Coating Corrosion Protection Plan

Water-based Coating Corrosion Protection Plan