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Loading and unloading operations between ships and storage tank terminals

Safety and efficiency in hydrocarbon storage tank terminals.

Published: May 30, 2024

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Introduction

Loading and unloading operations between ships and storage tank terminals consist of a series of procedures and precautions of great importance in the global energy supply chain. These operations are fundamental to the distribution of hydrocarbons and to the security of the world’s energy supply. The efficiency and safety of these processes are imperative, involving risk management in port operations that can generate incidents and affect both the infrastructure and the environment.

This article aims to provide a detailed overview of the procedures to be followed in oil loading and unloading operations between ships and storage tank terminals. In addition, it will analyse the main associated risks and the mitigation strategies necessary to prevent incidents that may compromise both the infrastructure and the natural environment.

Storage tank terminals

Storage tank terminals are port facilities for the hydrocarbon industry, serving as reception, temporary storage and distribution points for liquid products. These terminals vary in size and capacity, accommodating different types of products, from crude oil to refined products, and are often located at strategic points to facilitate distribution. In addition to storage tanks, the terminal includes infrastructure for the safe handling and operation of petroleum products, such as pumping, metering, loading and unloading systems, safety and environmental control measures.

General process of loading and unloading operations

Loading and offloading operations require precise coordination and the use of advanced technologies to minimise risks and ensure efficiency. This distribution of oil is governed by international and local protocols that stipulate safety and operational practices to be followed, including transfer rate control, tank level monitoring and spill prevention.

For loading onto ships, the following general processes must be executed in parallel and perfectly coordinated:

Inventory maintenance: It is essential to maintain sufficient inventory of the required product at the storage tank terminal. This inventory can come from the refining area, the production area or even from other vessels.
Pumping process: Once sufficient inventory has been secured and operational and safety requirements have been met, the product is pumped from the tank terminal to the loading docks.
Loading onto ships: Finally, the product is loaded from the quayside onto the ships, thus completing the transfer.

Product loading process from storage tanks to the docks

This process involves a series of carefully coordinated steps to ensure the efficient and safe transfer of product to the vessel. The main steps are outlined below:

Preparation of the storage tank: Before loading begins, the level and quality of the product in the storage tanks is checked; this includes checking the temperature and chemical composition of the product, if necessary. The tanks should also be inspected to ensure that they are in proper condition and free of contaminants.
Preparation of the pumping station: The pumping station, which is responsible for moving the product from the storage tanks to the docks, must be prepared: check pumps, valves and flow meters, as well as ensure that all safety systems are operational.
Connection of the transfer lines: The automatic or manual block valves are then opened, allowing the fluid to circulate within the lines that transport the product from the storage tank terminal to the docks.
Start of pumping: Once all checks and connections have been completed, pumping of the product begins. The pumps are set to operate at a rate that maintains a stable pressure in the transfer line, appropriate for the type of product and the distance to the dock.
Continuous monitoring: During the loading operation, the flow rate, pressure, and temperature are continuously monitored. It checks for unexpected variations that could indicate problems, such as leaks or blockages in the line.
Vessel communication: Vessel liaison should communicate regularly with personnel on board the vessel to ensure that they are prepared to receive the product and that transfer rates are appropriate for their storage systems.
Completion of loading: Once the product has been transferred, valves are closed to stop the flow, lines are drained or purged depending on the product to minimise residues in the pipelines.
Disconnection of lines: The transfer lines are safely blocked by closing the automatic or manual valves, ensuring that there are no spills or leaks during the process.
Documentation and recording: Finally, the necessary documentation is completed, including the exact amount of product transferred and any relevant observations during the process. This documentation must be kept for accounting, invoicing and compliance with environmental and safety regulations.

This process must be supervised by qualified personnel trained to handle the specific products and to act quickly in case of any anomaly during the transfer.

Loading and unloading process between storage tank terminals and ships

This is a complex operation involving a series of carefully coordinated steps to ensure safety, efficiency and environmental protection. The main steps involved in this process are described below:

Vessel arrival: The vessel to be loaded or unloaded arrives at the port and is met by tugboats that help manoeuvre and position the vessel safely on the terminal quay.
Mooring: Once in position, the vessel is moored using special cables and ropes to secure it firmly to the quay. This phase is significant to avoid unwanted movements during the loading or unloading operation.
Connection of hoses or loading arms: After securing the vessel, the hoses or loading arms are connected between the vessel and the terminal facilities. These connections must be watertight to prevent leakage and ensure safety. The type of connection depends on the product to be transferred (oil, chemicals, gas, etc.).
Safety tests and checks: Before liquid transfer commences, pressure tests are carried out and safety systems are checked both on the vessel and at the terminal. This includes checking emergency valves, leak detectors, and spill containment systems.
Start of transfer: Once everything is safe and the tests are satisfactory, the transfer of the liquid begins. Operations must be constantly monitored and flow rates adjusted to ensure adequate pressure and to avoid excessive stress on the hoses or loading arms.
Constant monitoring: During the transfer, the process is continuously monitored by trained personnel, weather conditions, vessel stability, and adjustments are made as necessary to maintain safe operation.
Completion of the loading and unloading operation: Once the product transfer is complete, the valves are closed and the hoses or loading arms are disconnected. Ensure that there is no product residue on the connections.
Disconnecting and unmooring: After ensuring that all connections are clean and secure, the vessel is unmoored and prepared to leave the dock under the assistance of the tugs.
Documentation and reporting: Finally, all necessary documents are completed, including the cargo manifest and the quantity and quality certificates. These documents are necessary for tracking, invoicing and legal compliance.

This process must comply with strict international and local regulations to ensure the safety of the operation, the protection of the environment and the integrity of the transported product.

Security of supply

Security of supply is maintained through effective management of storage terminals, ensuring that sufficient operational and strategic reserves are in place. This involves careful logistics planning and constant assessment of market demand and supply.

Port security

Port security is regulated by a number of international standards and criteria designed to protect ports and maritime operations from security-related threats and risks. These are the main regulations and organisations that govern port security:

International Maritime Organisation (IMO): The IMO is a specialised agency of the United Nations responsible for regulating maritime security at the international level. The IMO developed the ISPS Code and continues to oversee its implementation and updating.
International Ship and Port Facility Security Code (ISPS Code): This is the main standard for port security worldwide. It was adopted by the International Maritime Organisation (IMO) in December 2002 in response to the attacks of 11 September 2001. The code establishes a framework for assessing risks and security threats to ships and port facilities and for implementing appropriate security measures.
National Port Authorities: Each country has its own port authority or authorities that regulate and oversee operations and security in its ports. These authorities are responsible for ensuring compliance with international and local regulations in the ports under their jurisdiction.
Customs and Border Protection: Customs and border protection agencies also play an important role in port security, especially in the inspection of cargo and the prevention of smuggling and other illegal activities.
International and regional organizations: There are other international and regional organisations that can influence port security policies, such as the European Union, which has specific regulations for the ports of its member states. The ILTA (International Liquid Terminals Association) is a non-profit trade association representing liquid storage terminal operators worldwide, among others.

These standards and organisations work together to create a safe and secure environment for shipping, commerce and port operations, protecting both the infrastructure and the people who work or make use of these facilities.

Risk management in port operations

Risk management in port operations includes the assessment of potential hazards, such as oil spills, fires, and occupational accidents. Preventive measures range from the safe design of facilities to the continuous training of personnel and the implementation of emergency detection and rapid response systems.

Case studies

Through the analysis of real cases, areas for improvement can be identified and best practices in the industry can be reinforced. These cases serve as reminders of the importance of following rigorous safety and operational standards.

Conclusions

Loading and unloading operations between storage tank terminals and vessels are complex and require constant attention to detail and safety. Investment in technology, training and best practices are critical to mitigate risks and ensure the efficiency of these essential operations.