A storage tank is a large container designed to hold and store liquids, compressed gases, or mediums for the short- or long-term storage of heat or cold. These tanks are utilized in various industries, such as agriculture, manufacturing, and energy. They come in different shapes and sizes, storing water, chemicals, oil, gas, or other substances.
Particularly crucial in industries like petrochemicals, a storage tank functions as a sizable vessel for storing oil, gas, and other petrochemical products. Overall, storage tanks are pivotal in providing a reliable means to store and manage substantial quantities of liquids or gases for later use or distribution.
Storage tanks play a crucial role in various industries by providing a secure and efficient means of storing liquids, gases, and other substances. Selecting an appropriate storage tank type is vital to meet the specific requirements of different applications.
1. Fixed-Roof Tanks
Fixed-roof tanks are a cost-effective and commonly used design for storing liquids. Typically, they consist of a cylindrical steel shell with a cone- or dome-shaped roof permanently attached. Modern versions are usually welded for liquid and vapor tightness. These tanks may have a Breather Valve for pressure-vacuum regulation, but older tanks might not be completely vapor-tight.
| Application |
Advantages |
| Liquid Storage |
Cost-effective construction |
| Petrochemicals |
Simple design for basic storage needs |
| General Industry |
Low maintenance requirements |
| Agriculture |
Easy access for monitoring and maintenance |
2. External Floating Roof Tanks
External floating roof tanks feature a roof that floats on the liquid’s surface, rising and falling with the liquid level. The roof, composed of a deck, fittings, and a rim seal system, covers the liquid surface, minimizing evaporative losses. Floating roof decks come in configurations like pan, pontoon, or double deck, each emphasizing different characteristics.
| Application |
Advantages |
| Liquid Storage |
Minimized evaporative losses |
| Petrochemicals |
Prevents exposure of liquid on tank walls |
| Oil Industry |
Versatile deck configurations for specific needs |
| Environmental Compliance |
Reduces standing storage loss |
3. Internal Floating Roof Tanks
Internal floating roof tanks have a roof that floats on the liquid surface or is supported by pontoons above the liquid. They can have a fixed roof with vertical columns or a self-supporting fixed roof without internal columns. Internal floating roofs rise and lower with the liquid level, providing a barrier between the stored liquid and the atmosphere.
| Application |
Advantages |
| Chemical Storage |
Minimized vapor space and emissions |
| Oil Refineries |
Enhanced environmental and safety compliance |
| Liquid Petrochemicals |
Reduced withdrawal loss |
| Storage of Volatile Substances |
Vapor containment for safety |
4. Domed External Floating Roof Tanks
Domed external floating roof tanks combine a heavy-duty deck with a fixed roof on top of the shell. The fixed roof serves not only as a vapor barrier but also as a wind block. Self-supporting aluminum dome roofs are a popular type, fluidly ventilated similar to internal floating roof tanks.
| Application |
Advantages |
| Petrochemical Storage |
Enhanced vapor containment |
| Oil and Gas Industry |
Wind resistance and stability |
| Environmental Protection |
Reduced vapor emissions |
| Liquid Storage in Adverse Conditions |
Self-supporting dome for added strength |
5. Horizontal Tanks
Horizontal tanks, often used in both above- and below-ground applications, have a horizontal orientation to ensure structural integrity. These steel tanks are equipped with pressure-vacuum vents, gauge hatches, and sampling wells. Cathodic protection may be applied to prevent corrosion in underground tanks.
| Application |
Advantages |
| Liquid Storage |
Space-efficient design |
| Agriculture |
Easy integration into existing systems |
| Petrochemical Industry |
Cathodic protection for corrosion resistance |
| General Industrial Storage |
Structural integrity for diverse applications |
6. Variable Vapour Space Tanks
Variable vapor space tanks are equipped with expandable or flexible sections that adjust the internal vapor space as the liquid level changes. These tanks may feature a flexible diaphragm that expands and contracts with vapor space requirements, ensuring optimized containment.
| Application |
Advantages |
| Liquid Storage |
Flexible vapor space management |
| Volatile Substances |
Optimized vapor containment |
| Environmental Protection |
Minimized vapor loss |
| Chemical Industry |
Adjustable space for varying quantities |
7. LNG (Liquefied Natural Gas) Tanks
LNG tanks are specialized containers designed to hold liquefied natural gas at cryogenic temperatures. These tanks are typically double-walled, with the inner tank holding LNG and the outer tank providing insulation. LNG tanks ensure safe and efficient storage of natural gas in its liquid form.
| Application |
Advantages |
| Natural Gas Storage |
Efficient cryogenic storage |
| Energy Industry |
Double-walled construction for safety |
| Global Distribution |
High capacity for long-term storage |
| Energy Security |
Enhanced insulation and vapor containment |
Bunkering refers to the process of supplying fuel to ships, while a bunker refers to fuel and oil. This fuel is used to run machinery on board the vessel and to power the engines that propel the ship across the ocean. Bunkering can be performed both onshore and offshore.
Types of Bunkering
- Onshore Bunkering: Conducted at ports, where ships dock to receive fuel.
- Offshore Bunkering: Fuel is supplied to ships anchored offshore, often using a barge or tanker.
Bunkering Risks
While essential, bunkering comes with certain risks, including oil spills, fire hazards, and fuel contamination. Adhering to stringent safety standards and protocols is crucial to mitigating these risks during operations.
