Regarding rust prevention treatment inside pressure vessels

Detailed description of VCI anti-rust powder: An anti-rust powder that can be used in both dry and wet conditions. Vapor-phase anti-rust powder is a white, powdery anti-rust material that is soluble in water; it can be used in dry conditions by being sprayed on the inner surfaces of pipes, tanks, containers, etc., to prevent rust, or it can be placed in powder bags to serve as an auxiliary agent for rust prevention. Wet use: After being dissolved in water, it is used for pressure testing of products such as boiler water and water pumps. Specifications: 2.5 grams, 5 grams, 10 grams, 50 grams, 100 grams, 200 grams per non-woven bag; bulk: 25 kilograms per bag. Various specifications can be customized to meet customer requirements. Advantages: 1. It possesses excellent rust prevention properties, with a rust protection period of over 2 years; 2. The rust prevention particles can penetrate into every corner of the packaging, providing effective rust protection in areas that other rust prevention products cannot reach; 3. It saves labor and time, reduces costs, and is environmentally friendly and non-toxic; 4. The chemicals contained in this product are commonly used as food additives, and it does not contain heavy metals such as silicates or phosphates, making it safe to use; 5. When dissolved in water for pressure testing, it remains effective even when reused. Usage amount: For dry use, 50–100 grams of rust prevention powder per cubic meter is required; for wet use, the powder is used in a 2% aqueous solution and can be reused. Application areas: Inner surfaces of pressure vessels, turbines, tanks, boilers, heat exchangers, pipes, fittings, ships, components of hydraulic testing equipment, as well as vehicle bodies, engines, flywheels, brake discs, and various steel parts. machinery, etc. Ship and aviation industries: engines, motors, turbines, and other related components. Others: bearings, hand tools, drills, power tools, etc. Applicable metals: steel, cast iron, stainless steel, electroplated metals, copper and alloys, cadmium and alloys, chromium and alloys, tin and alloys, zinc alloys, nickel alloys

When used in cycles, is it still necessary to add rust prevention powder? Is the cost of using VCI rust prevention powder for rust prevention very high? For example, is it not appropriate to use this method to prevent rust in a 27-cubic-meter carbon steel tank, with the cost of rust prevention exceeding that of the tank itself?