Sodium bicarbonate is highly hygroscopic and prone to caking. Being moisture-absorptive by nature, it absorbs moisture and forms lumps under high ambient humidity. Once caked, even if the powder meets all specifications at factory dispatch, it will lead to poor silo discharge and nozzle blockage upon arrival, directly shutting down the entire flue gas treatment system. For overseas tender projects such as those in Poland, this poses a major challenge across the supply chain and logistics chain.
Packaging Selection (Compatible with Discharge Conditions at European Plants)
Most European sludge incineration plants use big bags (1000–1200 kg) suitable for pneumatic unloading; 25 kg small bags are adopted in a small number of scenarios. Key requirements: Big bags must be laminated PP woven bags with an inner PE liner. Ordinary woven bags are prohibited. Large temperature fluctuations inside shipping containers during ocean transit easily cause condensation (commonly known as "container rain"). Without the barrier of an inner liner, the cargo absorbs moisture and cakes at sea, rendering it unusable upon arrival at the port, with all losses borne by the supplier. If wooden pallets are used for shipments to the EU, pallets must be fumigated with a fumigation certificate provided; otherwise, the cargo will be detained at the destination port during customs clearance.
Key Risk Control Measures for Ocean Freight
Sodium bicarbonate is classified as general cargo for ocean shipment, with three critical points to note:
① Containers shall not be overfilled. Compaction of powder caused by vessel motion at sea, combined with condensation inside the container, will significantly increase the risk of hard caking;
② Prioritise dry and sound containers. Reject leaky, corroded and aged containers. Avoid stowing containers close to cold or hot pipelines in the hold to reduce condensation induced by temperature differences;
③ The cargo must not be shipped in the same container alongside acidic chemicals. If packaging ruptures and the material comes into contact with acidic substances, a chemical reaction will occur to generate carbon dioxide gas.
Inland Haulage at Destination Port and On-site Storage Control
After discharge at the port, goods are transported by land to the sludge incineration plant. Humidity tends to be high in Europe during autumn and winter, so transport trucks shall be properly covered against rain. After unloading, the material is transferred to an airtight on-site silo. Silos must be kept dry and sealed and fitted with arch-breaking devices. Even if test results at factory release are fully compliant, prolonged open storage on site will allow continuous moisture uptake from ambient air and result in caking and material failure.
Many suppliers focus solely on factory test reports while neglecting moisture control across the entire logistics chain. This often results in non-conforming material on site and represents a frequently overlooked hidden risk in overseas sodium bicarbonate tender projects.
Information Sources
- Material physicochemical properties: Hygroscopic characteristics of inorganic sodium bicarbonate powder, technical documents on chemical powder storage and transportation
- EU wooden packaging quarantine: EU Regulation (EU) 2016/2031 on plant health, IPPC fumigation requirements
- Container condensation and ocean stowage segregation rules: Practical guidelines for international container transport, IMDG general cargo compatibility guidance
- Discharge methods at European sludge incineration plants, PE liner requirements for big bags, silo storage solutions: Engineering experience from comparable Poland/EU flue gas deacidification EPC export projects
- Project risk cases: Lessons learned from logistics failure reviews of overseas tender projects adopting sodium bicarbonate dry flue gas cleaning
Explore More
