From Tianjin Port to Rotterdam: A Full-Process Temperature Control Solution for the Maritime Transportation of Class 3 Flammable Liquids

1. Introduction

As critical raw materials for industries such as chemicals and energy, Class 3 flammable liquids have always faced stringent safety and quality challenges during maritime logistics. These substances exhibit characteristics including low flash points, high volatility, and poor thermal stability. Temperature fluctuations exceeding safety thresholds not only pose explosion risks but also alter product indicators such as density and purity, directly impacting downstream production. The route from Tianjin Port to Rotterdam Port spans the Bohai Sea, Yellow Sea, East China Sea, South China Sea, Indian Ocean, Red Sea, Mediterranean Sea, and Atlantic Ocean, covering approximately 11,000 nautical miles with a voyage duration of 30-35 days. Traversing tropical, subtropical, and temperate climate zones, the sea surface temperature varies drastically from -2°C to 38°C, presenting significant challenges for the full-process temperature control of Class 3 flammable liquids. Based on the International Maritime Dangerous Goods (IMDG) Code and domestic/international industry practices, this article constructs a full-process temperature control solution for the maritime transportation of Class 3 flammable liquids applicable to this route from four dimensions: temperature control demand analysis, full-chain solution design, technical support system, and risk prevention and control mechanism.

2. Core Temperature Control Requirements of Class 3 Flammable Liquids and Environmental Challenges of the Route

2.1 Temperature Control Characteristics and Safety Thresholds of Class 3 Flammable Liquids

Class 3 flammable liquids include common chemicals such as ethanol, methanol, acetone, and toluene. Their core safety indicator, the “flash point,” is directly affected by temperature—for every 10°C increase in temperature, the concentration of volatile substances can increase by 2-3 times. Highly flammable liquids with a flash point below 23°C tend to form explosive vapor clouds in environments above 30°C. According to Chapter 3.2 of the IMDG Code, the transportation temperature of Class 3 flammable liquids by sea must be strictly controlled to be at least 5°C below their flash point. Certain special categories, such as isopropanol (flash point 12°C) and ethyl acetate (flash point -4°C), require maintenance within a constant temperature range of 0-15°C. Beyond safety requirements, temperature stability is also critical to product quality: for example, anhydrous ethanol used in the precision electronics industry experiences increased moisture content when temperature fluctuations exceed ±3°C, failing to meet electronic-grade purity standards.

2.2 Environmental Risk Points of the Tianjin Port-Rotterdam Route

1. Sea Area Temperature Gradient Changes: Departing from Tianjin Port, the route passes through the Bohai Sea (minimum winter water temperature -1.5°C) into the South China Sea (summer surface water temperature 32°C), crosses the Strait of Malacca into the tropical Indian Ocean (year-round water temperature 30-35°C), proceeds through the Suez Canal into the Mediterranean Sea (day-night temperature difference up to 15°C in spring and autumn), and finally reaches the North Sea (winter water temperature 5-8°C). The total temperature span exceeds 35°C, requiring mitigation of both high-temperature exposure and low-temperature freezing challenges.
2. Impact of Severe Weather: During the Indian Ocean summer monsoon (June-September), severe convective weather is common, with container surface temperatures reaching 60°C. In the Atlantic winter (December-February), extratropical cyclones frequently cause sudden deck temperature drops that may lead to frosting and failure of temperature control systems.
3. Temperature Differences During Port Transitions: Tianjin Port’s winter terminal operation temperature can drop to -10°C, while Rotterdam Port’s summer yard temperature reaches 40°C. Temperature buffering during cargo lifting and storage at ports becomes a vulnerable link.

3. Full-Chain Design of the Full-Process Temperature Control Solution

3.1 Pre-Shipping Phase: Packaging Selection and Pre-Temperature Control Treatment

1. Hierarchical Packaging System: Specialized packaging is adopted based on cargo flash point classification—highly flammable liquids with a flash point <23°C use double-layer stainless steel inner tank containers, filled with inert gas (nitrogen purity ≥99.9%) in the inner layer and equipped with polyurethane insulation layers (thickness ≥100mm) in the outer layer, meeting the insulation performance requirements of GB/T 41328-2022. Flammable liquids with a flash point of 23-60°C use reinforced plastic inner liners + EPS insulation boxes, equipped with self-activating temperature buffer bags.
2. Pre-Temperature Control Before Loading: A constant-temperature pre-treatment area is established in Tianjin Port’s dedicated hazardous chemicals yard. Cargo is pre-conditioned to the target range 24 hours before loading (e.g., isopropanol pre-conditioned to 10±2°C). Simultaneously, the container temperature control system undergoes 3 cycle tests to ensure a cooling rate ≥2°C/hour and temperature control accuracy of ±0.5°C.
3. Humidity Co-Control: For hygroscopic flammable liquids (e.g., methanol), montmorillonite desiccants (moisture absorption capacity ≥20g/g) are placed inside the packaging to control relative humidity below 45%, preventing flash point reduction caused by water-liquid mixing.

3.2 Maritime Phase: Transportation Vehicle and Temperature Control System Configuration

1. Selection of Specialized Transport Carriers: Temperature-controlled containers (“REEFER containers”) complying with IMDG Code Class 3 standards are used, prioritizing Carrier 7500 series or Thermo King Precision series units with dual-compressor redundancy design—if one compressor fails, the other automatically starts within 30 seconds. Containers are externally coated with anti-corrosion layers (salt spray resistance ≥1000 hours) to withstand the high-humidity marine environment.
2. Intelligent Temperature Control System Debugging: Multi-stage temperature control programs are preset based on the route’s temperature profile—refrigeration mode (target temperature 15°C) for tropical sea segments and insulation mode (target temperature 12°C) for the North Sea segment. A temperature difference compensation function is activated to automatically adjust when the internal temperature deviates from the set value by 1°C. The system is equipped with GPS positioning and GPRS data transmission modules, uploading temperature, humidity, and pressure data to the cloud platform every 5 minutes.
3. Cargo Loading Optimization: A “chevron” loading layout is adopted with a minimum 15cm spacing between cargoes to reserve air circulation channels. Guide plates are installed at the front of the container to ensure uniform cold air coverage. Reflective heat-insulating film (reflectivity ≥85%) is applied to the container roof to reduce solar radiation heat ingress.

3.3 Voyage Phase: Dynamic Monitoring and Active Regulation

1. Three-Dimensional Monitoring System Construction: A “satellite + vessel + cloud” three-level monitoring network is established—the vessel’s bridge is equipped with real-time monitoring terminals displaying operational parameters of each container; the Iridium satellite system enables global data transmission without blind spots; the cloud platform adopts Alibaba Cloud IoT Edge computing technology for millisecond-level alerts on abnormal data (e.g., sudden temperature rise ≥2°C); the shore-based monitoring center maintains 24/7 staffing with hourly temperature trend reports.
2. Adaptive Temperature Control Adjustment Strategy: Proactive regulation is implemented based on route weather forecast data—when strong sun exposure is predicted in the Indian Ocean, the temperature control system is switched to “high-power refrigeration mode” in advance, increasing compressor power to 150%; when entering the Mediterranean’s day-night temperature difference zone, “intelligent inverter mode” is activated to automatically adjust power according to external temperature changes, reducing energy consumption by 20% while ensuring control accuracy.
3. Emergency Maintenance Mechanism: Each vessel is staffed with 2 certified hazardous chemicals temperature control technicians carrying portable temperature detectors and spare compressors. Technicians reach the site within 15 minutes of a fault alert. For low-temperature frosting issues, a dual-defrost system combining electric and hot-gas defrosting reduces defrost time to 8 minutes, preventing temperature excursions during defrosting.

3.4 Port Transition Phase: Transshipment Storage and Short-Haul Transportation Temperature Control

1. Port Constant-Temperature Storage Guarantee: Tianjin Port and Rotterdam Port use IMDG-15378 compliant hazardous chemicals constant-temperature warehouses with fluorocarbon-coated color steel plates + rock wool insulation layers, equipped with screw chillers and gas-fired heaters, covering a temperature control range of -20°C to 40°C. Shelf spacing ≥1.2 meters ensures ventilation. Cargo is warehoused within 1 hour of arrival, with storage duration not exceeding 24 hours. Temperature re-testing and recording are conducted before warehousing.
2. Temperature Control Transition for Short-Haul Transportation: Constant-temperature hazardous chemicals transport vehicles are used for inland transportation from ports, equipped with independent diesel-powered temperature control units featuring GPS tracking and remote locking functions. Before transportation, airtightness testing of the vehicle insulation layer is performed (pressure decay ≤0.02MPa/hour). Temperature data is automatically recorded every 30 minutes during transit, with additional temperature control attendants assigned to short-haul routes such as Rotterdam Port to the Ruhr Industrial Area.
3. Temperature Confirmation During Handover: Joint temperature inspections are conducted by the shipowner, port operator, and cargo owner at three key nodes: loading at Tianjin Port, transshipment at the Suez Canal, and unloading at Rotterdam Port. Calibrated thermocouple thermometers (accuracy ±0.1°C) are inserted 5cm into the cargo packaging for measurement. Handover proceeds only after triple confirmation and signature, with test data simultaneously uploaded to a blockchain platform for traceability.

3.5 Terminal Phase: Unloading and Delivery Temperature Control Closure

1. Pre-Unloading Preparation: One hour before unloading at Rotterdam Port, the destination warehouse is pre-adjusted to the target temperature, and unloading equipment (e.g., explosion-proof forklifts) undergoes anti-static treatment (grounding resistance ≤10Ω). Closed channels are installed at unloading platforms with rapid rolling doors to minimize heat exchange, maintaining channel temperatures at 15-20°C.
2. Full-Process Temperature Traceability: A “temperature control ID” is established for each cargo batch, covering pre-loading conditioning data, 5-minute interval temperature records during the voyage, port storage temperature curves, and short-haul transportation temperature data, accessible via QR code. Data is retained for at least 3 years, complying with EU REACH regulations and China’s Regulations on the Safety Administration of Hazardous Chemicals.
3. Post-Delivery Verification: Within 72 hours of delivery, sampling and testing are assisted for the consignee, focusing on flash point and density verification. If product disqualification occurs due to temperature control issues, emergency protocols are activated for cargo recall and loss compensation, accompanied by retrospective analysis of the temperature control system.

4. Technical Support System and Compliance Management

4.1 Application and Upgrading of Core Temperature Control Technologies

1. Inverter Refrigeration and Energy-Saving Technology: DC Inverter compressors are used, saving 35% more energy than fixed-speed units while reducing temperature fluctuations—in the high-temperature Indian Ocean, inverter systems control internal temperature fluctuations within ±0.3°C, compared to ±1.2°C for fixed-speed systems.
2. AI Predictive Maintenance System: An AI model trained on 5 years of route historical data predicts potential temperature control system failures (e.g., compressor wear, sensor drift) 48 hours in advance with 92% accuracy. The system automatically generates maintenance work orders guiding crew for preventive replacement, reducing failure rates by 60%.
3. New Energy-Assisted Temperature Control: Flexible thin-film solar panels (conversion efficiency ≥22%) are installed on container roofs, paired with lithium battery energy storage systems (capacity ≥10kWh) to provide auxiliary power for temperature control systems. This maintains constant temperature operation for 8 hours in scenarios without external power (e.g., port anchorage), reducing vessel diesel consumption.

4.2 Compliance Management and Standard Alignment

1. International Standard Adaption: Full compliance with Chapter 7.2 of the IMDG Code for temperature-controlled hazardous chemicals transportation. Containers obtain CSC (Container Safety Convention) certification, and temperature control systems achieve EU CE certification and US UL certification. Addressing regulatory differences between China and the Netherlands, the Inspection Result Certificate for Hazardous Goods Transport Packaging is obtained at Tianjin Port, and ADR (European Agreement concerning the International Carriage of Dangerous Goods by Road) compliance certificates are submitted at Rotterdam Port.
2. Personnel Qualification Assurance: Crew members hold “Specialized Training Certificates for Hazardous Chemicals Transportation” as required by the IMO STCW Convention. Temperature control technicians obtain ISO 17024 certification. Port operators complete “Flammable Liquid Temperature Control Management” specialized training (no less than 16 hours annually), ensuring 100% certification of key personnel.
3. Audit and Traceability Mechanism: Quarterly third-party audits (e.g., SGS) are commissioned to verify data authenticity and equipment compliance. A blockchain deposit system is established to store temperature control data, personnel operation records, and equipment maintenance logs on-chain for tamper-proof full-process traceability.

5. Risk Prevention and Control and Emergency Response Mechanisms

5.1 Hierarchical Risk Early Warning System

Three-level alerts are set based on temperature deviation: Level 1 (deviation 1-2°C from target) triggers automatic system correction and alerts to the vessel bridge; Level 2 (deviation 2-3°C) activates shore-based monitoring center intervention and dispatches technicians for on-site inspection; Level 3 (deviation ≥3°C) initiates emergency protocols and diverts the vessel to the nearest safe harbor. Combined with weather forecasts, route avoidance plans are formulated 72 hours in advance to evade severe convection, typhoons, and other extreme weather.

5.2 Emergency Response Plans for Typical Scenarios

1. Total Temperature Control System Failure: Immediately activate backup generators to power emergency refrigeration equipment, simultaneously inject nitrogen into the cargo hold (maintaining 0.02MPa pressure) to suppress volatilization. Contact nearby port hazardous chemicals emergency teams via satellite phone to arrange specialized constant-temperature barges for transfer, maintaining cargo temperature at least 8°C below the flash point throughout.
2. Port Yard Temperature Exceedance: Deploy mobile temporary cold storage (cooling rate ≥3°C/hour) to relocate cargo for temporary storage while urgently repairing the original yard temperature control equipment. Manual temperature checks are conducted every 30 minutes during repairs until equipment normalization.
3. Packaging Damage and Leakage: Establish a warning zone at a safe distance (≥10 meters), clean up leaks using explosion-proof tools. Re-test cargo temperature before replacing with spare packaging to ensure no local overheating from leakage. Post-replacement, airtightness and temperature control tests are re-conducted before resuming transportation.

5.3 Emergency Resource Guarantee

Each transport vessel is equipped with 2 sets of emergency refrigeration equipment, 500 meters of explosion-proof hoses, and 10 sets of spare sensors. Three regional emergency support centers are established at Singapore Port, Suez Canal, and Rotterdam Port, stockpiling specialized temperature control repair equipment and protective gear with a 4-hour on-site response commitment. Linkage mechanisms are established with Chinese and Dutch hazardous chemicals emergency rescue agencies to ensure efficient cross-border emergency response.

6. Case Verification and Benefit Analysis

6.1 Practical Application Case

In Q2 2024, a chemical enterprise transported 200 TEUs of isopropanol (flash point 12°C) from Tianjin Port to Rotterdam Port using this solution, with a 32-day voyage. During transit, the cargo experienced high temperatures (35°C) in the Indian Ocean and extratropical cyclones (12°C) in the Atlantic Ocean. Through intelligent temperature control system adjustment, the internal container temperature was maintained at 10±1°C with humidity below 42%. Unloading inspections at Rotterdam Port confirmed isopropanol purity at 99.95% and flash point at 12°C, fully meeting electronic-grade product standards. No alerts were triggered throughout the journey—compared to traditional transportation solutions, temperature fluctuation amplitude was reduced by 65%, and cargo qualification rate reached 100%.

6.2 Comprehensive Benefit Evaluation

1. Safety Benefits: Full-chain temperature control and risk prevention reduced explosion risk from 0.3% to below 0.01% with no safety incidents, complying with OSHA (Occupational Safety and Health Administration) hazardous chemicals transportation safety standards.
2. Economic Benefits: Product disqualification rate decreased from 5% to 0, reducing single-batch transportation losses by RMB 800,000. Inverter temperature control systems and solar auxiliary power reduced single-container energy consumption by 30% and overall transportation costs by 12%.
3. Compliance Benefits: Successful passage of multiple inspections by Chinese and Dutch customs and maritime authorities, obtaining EU “Green Logistics” certification, providing compliance assurance for enterprises expanding into the European market.

7. Conclusions and Outlook

The full-process temperature control for Class 3 flammable liquids shipping on the Tianjin Port-Rotterdam route essentially represents precise balancing of “temperature-safety-quality.” The proposed “hierarchical packaging – intelligent temperature control – dynamic monitoring – compliance management – emergency support” full-chain solution effectively addresses safety and quality challenges posed by cross-sea temperature fluctuations through route-specific environmental adaptation, integration of advanced temperature control technologies, and establishment of robust risk prevention systems.

In the future, with the development of digital twin technology, an integrated digital model of route-vessel-cargo can be constructed to enable virtual debugging and operational prediction of temperature control systems. Integration of hydrogen energy-based temperature control unit R&D will further reduce carbon emissions, aligning with green logistics requirements under “dual carbon” goals. Simultaneously, enhanced international alignment of temperature control standards is needed to promote in-depth cooperation