For condensation to occur in a container, 3 specific conditions must exist simultaneously:
1. A source of water vapour must be present
2. A temperature difference must occur
3. A pathway must exist to move water vapour to the cold surface.
Main sources of water vapour:
• Water left in the container after cleaning
• Ambient air
• Wooden pallets;
• Timber flooring, dunnage, etc.
Main causes of temperature differentiation:
• Different temperatures of individual cargo pieces in the stow
• Different temperatures between cargo pieces and containers during loading
• Changes of temperature and/or air flow inside the container
• Changes of temperature outside the container
Pathway for migration of water vapour:
• In the container itself
• Between the cargo pieces and the container wall
• Between adjacent cargo pieces
Desiccant, one of the moisture solutions in container:
The main components of the container desiccant are calcium chloride and montmorillonite. Under the condition of 25 °C and relative humidity of 80%, the maximum capacity of adsorbed water vapor can exceed 70%, and the performance of similar products in foreign countries can be reached. The pure montmorillonite desiccant, at 25 ° C, relative humidity of 80%, the adsorption amount is generally not more than 30%. This composite desiccant greatly improves the drying and dehumidifying performance while maintaining the montmorillonite properties.
Without any fillers, pigments and binders do not work for most acids and alkalis. After complete combustion by antistatic storage treatment and discharge treatment, only carbon dioxide and water vapor remain, which is an excellent gas permeability for environmentally friendly products. Liquid and solid molecules can not pass; waterproof, dust-proof, non-toxic and harmless, pure neutral; no mold under the same conditions (temperature 25 ° C, humidity 80%), moisture absorption rate is about 5 times that of ordinary silica gel. The moisture absorption is more than 150g. Compared with the traditional mineral desiccant (such as silica gel), the desiccant is made of natural montmorillonite mineral as the hygroscopic body and refined by special process. This product is 100% degradable.
The container desiccant application method
It can be placed directly in different directions within the container. The specific quantity depends on the type of goods, packaging materials, transportation cycle, weather changes on the way (temperature, humidity change), moisture-proof standards, etc. Generally 20-foot containers (containers) follow the need to absorb 8-16 Kilograms of water vapor must be used. If the desiccant is 70%, then 10-20 kg of desiccant should be placed. The amount of desiccant in a 40-foot container is doubled.
Main purpose of container desiccant
In addition to container ocean transportation, container desiccant can also be applied to container aviation, railway, highway transportation and cargo storage, and can also be directly applied to moisture-proof packaging of large machinery, electronics, communications and other equipment.