All floating roof tanks provide safe, efficient storage of volatile products with minimum environmental vapor loss. They're particularly useful in the petrochemical industry for products with high vapor pressure, such as naphtha, gasoline, and crude oil.
Reducing filling and breathing losses benefits the bottom line and helps to meet environmental regulations for the emission of volatile organic compounds (VOC) and air pollutants.
Floating Roof Tank Overview
Floating roof tanks are suitable for storage up to a vapor pressure of 11.1 psi. The roof comprises a steel, aluminum, or fiberglass deck that floats on the contents. A full-contact roof lies directly on top of the contents, whereas a skin and pontoon roof floats above it.
Guide on Floating Roof Tanks
A floating roof is a passive system. As the tank's liquid product level varies due to filling, emptying, contraction, and expansion, its buoyant roof rises or falls automatically to adjust to these changes. The floating roof maintains contact with the tank's sidewall as it slides up or down.
The presence of a floating roof covering the contents can reduce evaporation loss by over 90%. It also prevents the collection of harmful gasses and vapors that can burn or explode when mixed with air. Furthermore, floating roof tanks drastically reduce shell corrosion by eliminating vapors.
Types of Floating Roof Tanks
Internal Floating Roof Tank (IFR)
This all-weather tank has an exterior domed or conical roof shielding the floating roof from loading by sand, rain, or snow. It separates the contents from the environment, reducing air pollution and combustion dangers. The gas phase layer in the vapor space has a heat insulation effect, further reducing evaporation.
IFRs offer a practical way to store volatile liquids with the least amount of environmental damage. IFRs provide all-weather protection for the floating roof by shielding it from outside elements like sand, rain, or snow with an exterior domed or conical roof.
These tanks reduce the chance of combustion accidents and the possibility of air pollution by erecting a barrier between the environment and the contents being held.
Reduced evaporation rates are also a result of the gas phase layer in the vapor space acting as a type of thermal insulation. This design element improves the efficiency and safety of storing hazardous materials. IFRs frequently have sophisticated monitoring and control systems installed as well to guarantee peak performance and adherence to regulations.
External Floating Roof Tank (EFR)
It consists of an open-topped cylindrical steel shell with a single or double deck that floats on the surface of the stored liquid. A rim seal system between the tank shell and roof reduces evaporation and prevents contaminants from entering.
For the safe storage of volatile liquids, external floating roof tanks, or EFRs, offer a reliable option. EFRs, like Internal Floating Roof Tanks, have an open-topped cylindrical steel shell that ensures endurance and structural integrity. Optimizing storage capacity and operational efficiency, the floating roof, usually with a single or double deck, stays afloat on the liquid's surface.
The rim seal system, which is strategically fitted between the tank shell and the roof, is an important part of EFRs. By acting as a crucial barrier against evaporation, this seal reduces product loss and preserves the quality of liquids that are being stored.
The seal keeps outside impurities from entering the tank to further guarantee the integrity and purity of the contents being held. Because of their well-established ability to reduce environmental risks and adhere to strict regulations, EFRs are the material of choice for companies that handle hazardous products.
Two Basic Components of a Floating Roof Tank
Regardless of their design, all floating roof tanks have two basic components:
- The roof itself: This is the pan-like or pontoon deck that floats on the liquid.
- A peripheral seal: A flexible curtain-like seal called the shoe closes off the rim where the floating roof meets the sidewall.
Advantages of a Floating Roof Tank
A floating roof tank is the safest option for storing highly volatile petrochemical products. This type of tank is:
- Flexibility in storage capacity: Provides flexible use of storage capacity by adjusting to the volume of the contents.
- Economical and efficient vapor emission reduction: The most economical and efficient solution for reducing vapor emissions and product loss is offered.
- Environmental compliance: Reduces harmful VOC and pollutants entering the atmosphere to comply with environmental regulations.
- Protection against adverse weather and contamination: Protects the stored product from adverse weather such as wind, rain, and snow and prevents the entry of sand, dust, or other contaminants.
- Enhanced safety measures: Floating roof tanks help to provide a safer working environment by lowering the danger of incidents with volatile petrochemical products. The enclosed design reduces exposure to volatile gasses, lowering the risk of fires or explosions.
- Prolonged product lifespan: Floating roof tanks contribute to the preservation of the quality and integrity of stored petrochemical goods, increasing their useable lives and guaranteeing consistent performance. They do this by providing protection from the elements and reducing vapor emissions.
- Operational dependability: Floating roof tanks provide dependable storage options for enterprises that handle volatile liquids, supporting continuous operations and reducing downtime due to maintenance or product losses.
- Adaptable applications: Floating roof tanks offer a flexible and scalable way to store various petrochemical products. They can be tailored to meet diverse storage needs in various industries.
Disadvantages of a Floating Roof Tank
It’s important to note that a floating roof tank is only intended for "stabilized" products that can’t form large quantities of vapor underneath the floating roof.
- Limited suitability: Because floating roof tanks are primarily meant to store "stabilized" items that do not develop considerable vapor beneath the floating roof, they are only suitable for certain types of liquids.
- Maintenance requirements: Frequent inspection and maintenance are necessary for these tanks to maintain the integrity of components, including seals, pontoons, and drainage systems. if maintenance is not performed properly, there can be a risk to public safety and the environment due to leaks, structural deterioration, and operating disturbances.
- Environmental risks: While floating roof tanks can reduce vapor carbon dioxide emissions, there is still the possibility that they will spill products or cause accidents that could contaminate nearby ecosystems. Proper maintenance is crucial to preventing these kinds of hazards.
- Cost consideration: A floating roof tank's initial construction and continuing maintenance costs can be greater than those of other storage choices, which can influence project budgets and financial viability even though they offer advantages like lower vapor emissions and product loss.
- Operating difficulty: Floating roof tanks require specialized procedures for operation, which involve roof adjustment and monitoring systems, which can increase operational complexity and crew training requirements.
Safety Requirements for a Floating Roof Tank
The greatest risks to a floating roof tank are rim fires or incidents that result in the roof sinking or tilting. Safety is paramount when storing volatile petrochemical products. By following the safety procedures listed below, thorough safety considerations will be integrated into the operation and maintenance of floating roof tanks:
- The floating roof may not move past the specified low landing or vertical clearance positions. Conventional floating roof tanks have a low landing position of approximately 3’ (<1m) and require 5’ (1.5m) or more vertical clearance.All primary and secondary seals, adjustable roof supports, mixers, drains, swing lines, rolling ladders, etc. must be designed to operate without compromising the integrity of the floating roof.
- Rolling ladders, roof drains, and fire foam systems must be designed and installed so that the floating roof remains balanced.
- Measures should be taken to prevent the buildup of static electricity from friction around the rim.
- The pontoons must be liquid and vapor-tight, not distorting if the roof deck is loaded with rain or snow.
- Implementing comprehensive emergency response protocols, such as evacuation plans, fire suppression systems, and spill containment measures, is necessary to reduce the impact of crises and mitigate potential mishaps.
- All tank parts, including seals, pontoons, and support structures, should be inspected regularly to help detect possible problems early and avert catastrophic failures that could jeopardize the integrity and safety of the tank.
- Employees operating and maintaining floating roof tanks should receive thorough training to guarantee they have the abilities and know-how to carry out their responsibilities safely and efficiently, lowering the possibility of mishaps and accidents.
- Implementing continuous environmental monitoring systems may ensure regulatory compliance, minimize the influence on nearby ecosystems, and detect and manage any environmental dangers like leaks or emissions.
Take Action Now and Experience the Difference With T BAILEY, INC.
Internal and external floating roof tanks effectively control vapor emissions. T BAILEY, INC. can advise you on the best storage option for volatile petrochemicals, including gasoline, light diesel, crude oil, aviation oil, etc., and noxious chemicals such as benzene, toluene, and xylene.
We provide IFR and EFR tank design, manufacturing, assembly, and after-sales support according to the highest industry standards. Contact us today.
