Method for prolonging storage period of steel drum
By combining degreasing, water washing, silane treatment, drying, and vapor phase rust inhibitors, the problem of traditional rust prevention methods being unable to balance protective effect and economy is solved, achieving long-term rust prevention for high-cleanliness steel drums, reducing costs and extending the shelf life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-15
AI Technical Summary
Traditional rust prevention methods cannot balance protective effectiveness and cost-effectiveness, making it difficult to meet the short-term rust prevention needs of open steel drums used in high-cleanliness petrochemical industries.
The process involves degreasing, washing, silane treatment, drying, and filling with dry air and vapor phase rust inhibitor to form a dense silane film. The vapor phase rust inhibitor is then introduced to form a monomolecular protective layer, combining the deep dehumidification of dry air with the long-lasting protection of the vapor phase rust inhibitor.
Without the need for a protective coating, the shelf life of open steel drums can be extended to 3 months, reducing costs by 20%-40%, improving production flexibility, ensuring no rust on the inner wall, and adapting to the long-cycle turnover of the petrochemical industry.
Smart Images
Figure CN122039062A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of steel drum rust prevention technology, and specifically to a method for extending the storage period of steel drums. Background Technology
[0002] In the fields of petrochemicals, food, and high-end manufacturing, the cleanliness of the inside of steel drums used to hold raw materials or products directly affects product quality and safety. Therefore, steel drums must undergo strict internal surface treatment before leaving the factory. This treatment process usually includes key steps such as degreasing, washing, and silanization. Degreasing removes grease from the inner wall of the steel drum, washing removes residual chemicals, and silanization improves the compatibility of the steel drum for subsequent use by forming a conversion film.
[0003] While the above processes can thoroughly remove contaminants from the inner wall of the steel drum and meet high cleanliness requirements, they also completely strip away the temporary protective and rust-preventing oil film that comes with the steel at the factory, leaving the inner wall of the drum in a highly reactive "bare steel" state. In this state, the inner wall of the steel drum is extremely sensitive to humid air and is highly susceptible to electrochemical corrosion and rusting. This severely affects the storage, transportation, and use of the steel drum, and may even lead to contamination of the contained products and the scrapping of the drum.
[0004] Currently, two methods are commonly used for short-term rust prevention of high-cleanliness open-top steel drums. One is the dry air filling method, which reduces internal humidity by filling the treated steel drum with dry air to prevent rust. However, since open-top steel drums rely solely on simple sealing devices and the sealing is insufficient, dry air is prone to leakage and external humid air can easily penetrate. This method can only provide short-term protection for no more than one week, after which rust will appear. The other method is the internal spraying of protective coatings, which forms an isolation barrier by spraying special protective coatings. This can extend the rust prevention period to more than six months, but it will significantly increase production costs, and the coating may affect the sensitive chemicals subsequently contained or produce odors.
[0005] The single physical isolation method (coating method) is highly effective but also expensive, while the single environmental control method (dry air filling method) is low in cost, but its effectiveness is extremely low due to the limited sealing performance of the packaging itself. Neither of the two rust prevention methods can achieve both protective effect and economy, making it difficult to meet the short-term rust prevention needs of open steel drums for high-cleanliness petrochemical applications. Therefore, we propose a method to extend the storage period of steel drums to solve the above problems. Summary of the Invention
[0006] The present invention aims to provide a method for extending the storage period of steel drums, in order to solve the problem that traditional rust prevention methods cannot simultaneously achieve both protective effect and economy, and are difficult to meet the short-term rust prevention needs of open steel drums used in high-cleanliness petrochemical industries.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: a method for extending the storage period of steel drums, comprising the following steps: Step 1, Degreasing: Use an alkaline degreasing agent to soak or spray the steel drum at a temperature of 50-60℃ to remove all the grease from the inner wall of the steel drum. Step 2, Water washing: Continuously spray the steel drum with deionized water to remove residual degreasing agent and impurities; Step 3, Silane treatment: The steel drum is sprayed with a silane coupling agent at room temperature to form a dense silane film on the steel drum; Step 4: Drying: Place the steel drum in a drying oven to dry it, ensuring that there is no residual moisture on the inner wall of the steel drum; Step 5: Fill with dry air: Fill the steel drum with dry air until the dry air replacement rate in the steel drum reaches more than 80%; Step 6: Fill with vapor phase rust inhibitor: Fill the steel drum with vapor phase rust inhibitor until the vapor phase rust inhibitor diffuses inside the steel drum and fills the entire steel drum; Step 7: Seal and store: After filling with vapor phase rust inhibitor, immediately tighten the lid completely.
[0008] Preferably, as an improvement, the alkaline degreasing agent is set as a sodium carbonate composite degreasing agent with a concentration of 8-10 g / L and a total alkalinity of 10-12 pt.
[0009] Preferably, as an improvement, the dew point of the inflated dry air is ≤ -45℃, the inflation pressure is set to 0.3-0.4MPa, and the inflation time is set to 4-5 seconds.
[0010] Preferably, as an improvement, the concentration of the silane coupling agent is set to 5-10 g / L.
[0011] Preferably, as an improvement, the drying temperature of the drying oven for the steel drum is set to 200°C.
[0012] Preferably, as an improvement, the time for spraying deionized water onto the steel drum is set to 5-8 minutes.
[0013] The beneficial effects of this solution are as follows: During the filling process, the vapor-phase rust inhibitor molecules are evenly distributed throughout the entire internal cavity in the form of aerosol, and are rapidly adsorbed onto all metal surfaces, including complex structures such as welds and rolled edges, forming a monomolecular protective layer. Since the barrel opening is not absolutely sealed, dry air inside will slowly leak out, and humid air outside will slowly seep in. This is an unavoidable dynamic process. In traditional methods that only fill with dry air, this process directly leads to the failure of protection. However, in this invention, the volatile vapor-phase rust inhibitor molecules are continuously and slowly released from the adsorption carrier or the initially deposited micro-liquid throughout the storage period, constantly "replenishing" the vapor phase space. Even if a small amount of moisture seeps in, the vapor-phase rust inhibitor molecules inside the steel barrel can preferentially adsorb onto the metal active sites before water molecules, thereby continuously maintaining the integrity of the protective film. This solution extends the shelf life of open steel drums from one week to three months using the traditional dry air method without internal spraying. Compared to spray rust prevention, it eliminates the need for paint procurement, investment in spraying equipment, waste gas and wastewater treatment, manual construction, and drying and curing, reducing the unit cost of steel drums by 20%-40%. This significantly reduces the cost burden on enterprises and downstream customers. The deep dehumidification of dry air and the long-term protection of vapor phase rust inhibitors work synergistically to ensure that the inner wall of the steel drums remains rust-free during the three-month shelf life. This eliminates the need for emergency turnover in the short term, greatly improving the flexibility of enterprise production plans, reducing warehousing turnover pressure, and meeting the long-cycle turnover needs of materials in the petrochemical industry. Attached Figure Description
[0014] Figure 1 This is a flowchart illustrating a method for extending the storage period of steel drums according to an embodiment of the present invention. Detailed Implementation
[0015] The following detailed description illustrates the specific implementation method: Example The basic implementation examples are as follows: Figure 1 As shown, in this embodiment, all steel drums are open-faced steel drums used in petrochemical industries, with a volume of 216.5L and a height of 880mm. An EPDM rubber sealing ring is installed between the drum lid and the steel drum, and the drum lid is sealed to the opening of the steel drum using a wrench-type V-shaped drum hoop.
[0016] like Figure 1 The method for extending the storage period of steel drums, as shown, includes the following steps: Step 1, Degreasing: Use an alkaline degreasing agent to soak or spray the steel drum at a temperature of 50-60℃ to remove all grease from the inner wall of the steel drum. The alkaline degreasing agent is a sodium carbonate composite degreasing agent with a concentration of 8-10 g / L and a total alkalinity of 10-12 pt. In this embodiment, the concentration of the alkaline degreasing agent is set to 9 g / L and the total alkalinity is 10 pt. The spraying temperature is set to 55℃ and the spraying time is set to 5 minutes. Step 2, water washing: continuously spray the steel drum with deionized water for 5-8 minutes to remove residual degreasing agent and impurities. In this embodiment, the spraying time is set to 5 minutes. Step 3, Silane Treatment: Place the steel drum into the silane treatment tank, with both the top and bottom of the drum located within the top and bottom troughs. Spray the steel drum with a silane coupling agent at room temperature. The concentration of the silane coupling agent sprayed in the top and bottom troughs is set to 5 g / L, and the concentration of the silane coupling agent sprayed in the silane treatment tank is set to 10 g / L, so that a dense silane film forms on the steel drum. In this embodiment, the spraying time of the silane coupling agent is set to 3 minutes. Step 4: Drying: Place the steel drum in a drying oven and set the drying temperature of the drying oven to 200℃ and the drying time to 2 minutes to ensure that there is no residual moisture on the inner wall of the steel drum. Step 5: Fill with dry air: Insert the air filling tube of the dry air generator into the steel drum to a depth of 300mm. Start the dry air generator to fill the steel drum with dry air until the dry air replacement rate in the steel drum reaches more than 80%. The dew point of the filled dry air should be ≤ -45℃, the filling pressure should be 0.3-0.4MPa, and the filling time should be 4-5 seconds. In this embodiment, the dew point of the filled dry air is set to -50℃. Petrochemical steel drums have poorer corrosion resistance after degreasing and require a lower humidity environment. This parameter can ensure that the humidity inside the drum is reduced to below 3%, avoiding early corrosion caused by trace moisture. If the dew point is too high, deep dehumidification cannot be achieved, and the rust prevention effect will be significantly reduced. The filling pressure is set to 0.3MPa, and the filling time is set to 5 seconds. During the filling process, the original humid air in the steel drum is discharged through the gap between the drum lids. After filling is completed, tighten the drum lids. Step 6: Fill with vapor phase rust inhibitor: Open the lid and fill the steel drum with vapor phase rust inhibitor. In this embodiment, the vapor phase rust inhibitor is set as Shan Yi Chemical PART2 oil-free vaporization rust inhibitor. Fill the drum with vapor phase rust inhibitor until it diffuses and fills the entire drum. In this example, the amount of vapor phase rust inhibitor is 3-4 mL and the continuous filling time is 2 seconds. Step 7: Seal and store: After filling with vapor phase rust inhibitor, immediately tighten the lid completely.
[0017] Fifteen open-face steel drums with a specification of 216.5L for petrochemical use were selected and randomly divided into three groups of five. One group is an embodiment of the present application, and the other two groups are comparative examples 1 and 2. The initial material, specifications and storage environment (normal temperature, dry, ventilated, no corrosive gases, avoidance of direct sunlight and rain) of the three groups of steel drums were kept consistent. Only the rust prevention treatment methods were different. The condition of the inner wall of the steel drums under different storage periods was subsequently tested simultaneously.
[0018] Example: Five 216.5L open-face steel drums for petrochemical use were selected, and the method for extending the storage period of the steel drums in this example was used for the entire process.
[0019] Comparative Example 1 (dry air filling method): Five 216.5L open-face steel drums for petrochemical use were selected, and steps one to five were performed according to the method for extending the storage period of steel drums, while keeping the other storage conditions consistent.
[0020] Comparative Example 2 (Protective Coating Method): Five 216.5L open-faced steel drums for petrochemical use were selected. After performing steps one to four of the method for extending the storage period of steel drums, a special anti-corrosion coating for petrochemicals was sprayed inside the steel drums and cured at high temperature for 25 minutes. Finally, the drum lids were completely locked, and the remaining storage conditions were kept consistent.
[0021] The corrosion of the inner wall of the steel drums was tested after 1 week, 1 month, 2 months, and 3 months of storage (rust spots were observed and the percentage of rust area was measured). The cleanliness of the inner wall of the steel drums in Example 1 and Comparative Example 2 (residues detected by gas chromatography) and the unit cost were also tested. The results are shown in the table below:
[0022] Conclusion: The proposed solution achieves a similar rust-proof preservation period to traditional internal spraying of protective coatings on steel drums, while avoiding issues such as paint residue and high curing energy consumption associated with spraying. Furthermore, it effectively addresses the shortcomings of traditional dry air methods, such as short preservation periods and susceptibility to rust. This solution significantly extends the effective rust-proof preservation time of open-faced steel drums used in petrochemicals. The unit cost of this solution is 151 yuan per drum, compared to 200 yuan per drum for the traditional spraying method, representing a cost reduction of approximately 25%, while maintaining excellent rust-proof performance. This solution perfectly meets the comprehensive requirements of the petrochemical industry for cleanliness, rust-proof reliability, and cost control of open-faced steel drums.
[0023] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.
Claims
1. A method for extending the shelf life of steel drums, characterized in that: Includes the following steps: Step 1, Degreasing: Use an alkaline degreasing agent to soak or spray the steel drum at a temperature of 50-60℃ to remove all the grease from the inner wall of the steel drum. Step 2, Water washing: Continuously spray the steel drum with deionized water to remove residual degreasing agent and impurities; Step 3, Silane treatment: The steel drum is sprayed with a silane coupling agent at room temperature to form a dense silane film on the steel drum; Step 4: Drying: Place the steel drum in a drying oven to dry it, ensuring that there is no residual moisture on the inner wall of the steel drum; Step 5: Fill with dry air: Fill the steel drum with dry air until the dry air replacement rate in the steel drum reaches more than 80%; Step 6: Fill with vapor phase rust inhibitor: Fill the steel drum with vapor phase rust inhibitor until the vapor phase rust inhibitor diffuses inside the steel drum and fills the entire steel drum; Step 7: Seal and store: After filling with vapor phase rust inhibitor, immediately tighten the lid completely.
2. The method for extending the storage period of steel drums according to claim 1, characterized in that: The alkaline degreasing agent is set as a sodium carbonate compound degreasing agent with a concentration of 8-10 g / L and a total alkalinity of 10-12 pt.
3. The method for extending the storage period of steel drums according to claim 2, characterized in that: The dew point of the dry air to be filled should be ≤ -45℃, the filling pressure should be set to 0.3-0.4MPa, and the filling time should be set to 4-5 seconds.
4. The method for extending the storage period of steel drums according to claim 3, characterized in that: The concentration of the silane coupling agent was set to 5-10 g / L.
5. The method for extending the storage period of steel drums according to claim 4, characterized in that: The drying temperature of the drying oven for the steel drum is set to 200℃.
6. The method for extending the storage period of steel drums according to claim 5, characterized in that: The time for spraying deionized water onto the steel drum is set to 5-8 minutes.