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LPG BULK STORGE SYSTEM DESIGN SERVICES.

 

  • When it comes to storing Liquefied Petroleum Gas (LPG) in bulk (example 2,00,000 m3) , two main types of storage systems are commonly used: pressurized tanks and cryogenic tanks

  • Both methods are designed to maintain LPG in its liquid form for efficient storage and distribution,

  • but they rely on different physical principles and have distinct advantages and disadvantages based on operational, safety, and cost considerations.

PRESSURIZED TANKS


•    Storage at High Pressure: In pressurized tanks, LPG is stored at a pressure that is high enough to keep the gas in a liquid state at ambient temperatures.

 

Typically, LPG is stored in these tanks at pressures ranging from 8 to 20 bar (115 to 290 psi).
 

 temperature.


    For butane, pressures can go higher (up to 20 bar) since it has a higher boiling point than propane.


 •  Tank Design: These tanks are typically made from carbon steel, and they are designed to withstand the pressure exerted by the liquefied LPG.

 

 •  Vaporization Control: Pressurized storage systems allow for the gradual release of LPG as a vapor when needed, and the remaining liquid is kept under pressure.


SPHERICAL LPG TANKS

 

  • Spherical LPG tanks, also known as Horton spheres, are designed to store large volumes of liquefied petroleum gas efficiently., can have a maximum capacity ranging from 300 to 5,000 cubic meters (m³) .

 

  • For very large storage needs, some spherical tanks can hold up to 8,000 m³. 

 


  • To Storing 100,000 m³  & above multiple Spherical LPG tanks are require.


  • The maximum capacity of these tanks can vary, but they typically range from 10,000 to 75,000 barrels (approximately 300,000 to over 2,000,000 gallons). 

  • Spherical LPG tanks typically operate at pressures ranging from 8 to 25 bar (approximately 116 to 362 psi),

  •  

  • depending on the specific application and the type of LPG . The exact pressure can vary based on factors such as temperature and the design of the tank.


Bullet Tanks


Bullet tanks, also known as horizontal pressure vessels, 


•    Description: These are horizontal cylindrical tanks used for storing LPG under pressure. Bullet tanks are often used for smaller to medium volumes of LPG.
•    Capacity: Each bullet tank can typically store between 200 and 1,000 m³ of LPG. For

CRYOGENIC TANKS


Storage at Low Temperature: In cryogenic tanks, LPG is stored at very low temperatures (below the boiling point.

 

LPG, which is around -42°C for propane and -0.5°C for butane to maintain the liquid state.

 

This is achieved by cooling the LPG to cryogenic temperatures and storing it in insulated, double-walled tanks.


Temperature: The LPG must be cooled to cryogenic temperatures to convert it into a liquid at atmospheric pressure.


Tank Design: Cryogenic tanks are heavily insulated to maintain the low temperatures and prevent heat influx.

 

These tanks are typically double-walled with a vacuum or insulating material between the walls to reduce heat transfer.


 Vaporization: Cryogenic tanks store LPG at low pressure (close to atmospheric pressure), and the temperature must be maintained to keep the LPG in liquid form.

 

When LPG is needed, it is vaporized by applying heat or using vaporizer systems to bring it back to a gas state


 Regulations and Compliance


Codes and Standards: LPG storage systems are regulated by national and international safety standards, 

API 620 for cryogenic tanks.


 NFPA 58 (Liquefied Petroleum Gas Code) – Governs the design and installation of LPG systems in the U.S.


 ASME Boiler and Pressure Vessel Code (Section VIII) – For pressure vessels. pressurized tanks.


 International Fire Code (IFC) – Includes guidelines for storing flammable gases.


 API 2510 – Recommended practices for bulk LPG storage.

 Local Permits: Ensure you have all necessary permits from local regulatory bodies, such as the Environmental Protection Agency (EPA), Department of Transportation (DOT), and local fire safety authorities.


 Monitoring and Control Systems


 Level Monitoring: Automated level monitoring systems should be in place to track the amount of LPG in each tank, using sensors like radar or ultrasonic.


Pressure and Temperature Control: Tanks should be equipped with pressure-relief valves and temperature sensors to ensure safe storage conditions.


Leak Detection: Regular monitoring systems (e.g., gas detectors, visual inspection) should be installed to detect any leaks or signs of failure.


 Automated Controls: Systems to regulate and control the pressure and temperature inside storage tanks to maintain optimum conditions for LPG.
 

Transport and Distribution design services


For a bulk LPG storage facility, you will also need efficient transport and distribution systems, 


Pipeline Systems for transferring LPG from the storage tanks to refueling stations or distribution points.


 LPG Carriers and Trucks for transportation of LPG to end-users or other facilities.


Loading and Unloading Facilities for safe transfer of LPG to and from transport vehicles.


Risk Assessment and Safety Measures


Hazard Analysis: A thorough hazard analysis, such as a HAZOP (Hazard and Operability Study), should be conducted before construction.


Fire Safety: Install fire suppression systems (e.g., water sprays, foam systems) and ensure the facility meets safety distance requirements from nearby populated areas.


Training and Emergency Response: Regular training for personnel and emergency drills should be conducted to ensure swift response in case of an accident.


Long-Term Considerations


 Maintenance: Regular inspection and maintenance of storage tanks, valves, pressure systems, and safety equipment are essential for safe and efficient operations.


 Upgrades: The facility should be designed with the flexibility to expand in the future, should demand for storage increase.

LPG TANK FORM DESIGN


LPG tank form design considerations are crucial for ensuring the safety and efficiency of LPG storage. Here are some key factors to consider:


Tank Type:

 

Spherical Tanks: 
Ideal for large-scale storage due to their high strength-to-weight ratio.
Can withstand high internal pressures.
 

 Horizontal Cylindrical Tanks:

 
o    Commonly used for smaller storage capacities.
o    Easier to install and maintain.
o    May require more land area than spherical tanks.

 

Vertical Cylindrical Tanks: 


o    Often used for medium-sized storage.
o    Offer a good balance between strength and cost.
o    Require less height compared to spherical tanks.

Additional Considerations:
•    Foundation Design: The foundation should be strong enough to support the tank weight and withstand seismic loads.
•    Corrosion Protection: Tanks should be protected against corrosion, especially in harsh environments.
•    Insulation: Insulation may be required to maintain product temperature and reduce heat loss.
•    Environmental Impact: Consider the environmental impact of tank construction and operation, including potential leaks and emissions.


Case Study: LPG Storage Facility Design and Engineering for GBP Tanzania Ltd

Client Overview:


GBP Tanzania Ltd is a locally registered Tanzanian petroleum marketing company in the private sector. The company is actively engaged in the marketing and distribution of a wide range of refined petroleum products including Petrol, Diesel, Jet A1, Kerosene, Fuel Oil, and Industrial Diesel Oil across Tanzania.

As part of their expansion into the LPG (Liquefied Petroleum Gas) distribution business, GBP Tanzania Ltd. embarked on the development of a state-of-the-art LPG storage facility. This facility aims to bolster the country’s infrastructure for LPG supply and ensure safe and efficient handling of LPG products.

Project Overview:


Project Name: 20,000 MT LPG Storage Facility
Location: Tanzania
Client: GBP Tanzania Ltd
Engineering Design & Consultancy: Sandhya Engineering Consultancy


Project Scope:

 

Complete design, engineering, and provision of technical services for the construction and commissioning of a modern LPG storage facility, with all required support systems and infrastructure.

Facility Specifications and Scope of Work:


The proposed LPG storage facility is designed to handle and store a total of 20,000 metric tons (MT) of LPG. The facility includes a variety of critical infrastructure components aimed at ensuring efficient, safe, and reliable storage and distribution of LPG to meet local demand.

1. Storage Tanks


The facility features four (4) LPG storage tanks, each with a capacity of 3,000 MT, totaling 12,000 MT of LPG storage. The tanks are designed as Horten spherical tanks, renowned for their efficiency in storing liquefied gases and ensuring the integrity of the product under varying pressure conditions.

2. Tanker Loading and Offloading Bays


To facilitate the distribution of LPG to various regions, the facility includes 8 tanker loading and offloading bays. These bays allow for the seamless transfer of LPG from storage to road tankers for onward distribution. The bays are equipped with state-of-the-art equipment to ensure safe and efficient operations.

3. Vessel Loading and Receiving from Sea


The facility is designed with a CBM/Jetty for receiving LPG shipments from vessels. This enables efficient offloading and delivery of large quantities of LPG directly from sea-bound tankers to the storage facility.

4. LPG Loading Pumps


The facility includes 5 LPG loading pumps, with 4 working pumps and 1 standby. These pumps facilitate the transfer of LPG from storage tanks to tankers for distribution. The system is designed for high reliability, with the inclusion of a backup pump to ensure operations continue smoothly in case of any failure.

5. Bottling Pumps


A 25 cubic meter centrifugal bottling pump is included in the design, with 1 working pump and 1 standby. This system is essential for loading smaller quantities of LPG into cylinders for domestic and industrial use.

6. Vapor Compressors


The facility features 2 vapor compressors, with 1 working and 1 standby, to maintain pressure levels within the storage tanks and other related systems.

7. LPG Piping and Layout


Comprehensive LPG piping has been designed to ensure safe and efficient transportation of LPG between storage tanks, loading bays, and the vapor recovery system. Detailed P&ID (Piping and Instrumentation Diagrams) and layout drawings were provided to ensure correct implementation of the system.

8. Safety Systems


Given the hazardous nature of LPG, a strong focus has been placed on safety systems throughout the design. Key components of the safety system include:

Safety Area Layout:

 

Proper zoning of the facility to minimize the risk of accidents and exposure to hazardous areas.


Fire Pump House and Shed:

 

A dedicated fire pump house equipped with fire-fighting pumps to ensure rapid response in case of a fire.


Fire Fighting Deluge Valve System:

 

A fully integrated fire suppression system with deluge valves, ensuring swift and effective suppression of fires in high-risk areas.


Fire Fighting Water Calculations:

 

Detailed water calculation sheets to ensure adequate water supply for fire fighting needs.


Fire Water Tank Drawings:

 

Design and layout for a dedicated fire water storage tank.


9. Other Critical Infrastructure

 


In addition to the technical infrastructure, the facility design includes several essential support systems to ensure smooth day-to-day operations:

Office Building:

 

A centralized office space for staff operations and administration.
Electrical Room: A dedicated electrical room housing the power distribution system and equipment.


Empty Trucks Parking Facility:

 

A parking area designed for empty trucks, ensuring smooth traffic flow and reducing congestion in the facility.


Key Design and Engineering Features:


The design and engineering for the LPG storage facility was meticulously crafted to ensure optimal safety, operational efficiency, and compliance with industry standards.

The major engineering features include:

Modular Tank Design:

 

The Horten spherical tanks are modular in design, ensuring they are both cost-effective and capable of being easily maintained.


Advanced Control Systems:

 

The facility is equipped with advanced control and monitoring systems for both safety and operational efficiency. Automated systems ensure the smooth transfer of LPG between storage and distribution points.


Fire Protection Integration:

 

All components, including tanks, pipelines, and loading areas, are equipped with integrated fire suppression systems. This includes the installation of deluge systems, fire alarms, and water tanks to provide comprehensive fire protection.


Challenges and Solutions:


1. Safety Regulations Compliance


Given the highly flammable nature of LPG, ensuring strict compliance with safety regulations was a primary concern. The design team worked closely with local and international regulatory bodies to ensure that all safety standards were met or exceeded. Special attention was given to the layout of safety zones and fire suppression systems to minimize the risk of accidents.

2. Land Space Optimization


The available land for the storage facility was limited, which required an innovative approach to maximize storage capacity while maintaining necessary safety buffers. The spherical tank design was chosen for its compactness and efficiency in utilizing space.

3. Coordination with Multiple Stakeholders


The project required seamless coordination between different stakeholders, including the client (GBP Tanzania Ltd.), suppliers, contractors, and regulatory bodies. Regular meetings, detailed design reviews, and progress updates ensured that the project stayed on track and within budget.

Conclusion:


The LPG storage facility built for GBP Tanzania Ltd. is a cutting-edge facility designed to meet Tanzania's growing demand for LPG. With a total storage capacity of 20,000 MT and a full suite of state-of-the-art equipment for safe handling, storage, and distribution, the facility will play a crucial role in the growth of the LPG sector in Tanzania. The comprehensive design by Sandhya Engineering Consultancy ensures that the facility meets the highest standards of safety, efficiency, and reliability.

This project not only strengthens the local infrastructure for LPG distribution but also demonstrates the capacity of GBP Tanzania Ltd. to provide a steady and safe supply of LPG to meet the needs of households, industries, and businesses across the region.

 

 


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