1 API 650 Intro, Design of storage tanks

Summary

This video script focuses on API 653, covering the inspection and repair of above-ground storage tanks. It outlines the design process, emphasizing the tanks' role in storing various commodities like crude oil and LPG. The script discusses design codes to prevent disasters, highlighting the API 650 code's requirements for steel welded tanks, including storage of liquid fluids, support conditions, and pressure and temperature limits. It also explores different tank roof types, their mechanical design implications, and the importance of understanding roof configurations for load determination. The script further delves into floating roofs, their types, and their role in reducing evaporation losses, concluding with considerations for material selection and tank shell thickness calculations.

Takeaways

• 📚 API 653 is a standard for inspecting and repairing above-ground storage tanks, which are crucial for storing various commodities like crude oil, LPG, and water.
• 🔍 The primary purpose of storage tanks is to hold large quantities of fluid at a relatively low installation cost, operating mostly at atmospheric or near-atmospheric conditions.
• 🏗️ Design codes, including API 650, are used to prevent disasters and ensure safety by setting minimum requirements for design, fabrication, material selection, inspection, and installation.
• 🚫 Tanks designed with API 650 can only store liquid fluids, must have a bottom supported by sand, gravel, or concrete, and must operate with internal pressure below 17 kilopascals and temperatures below 93 degrees Celsius.
• 🔧 The API 650 code is divided into two main parts: the first part contains mandatory requirements, and the second part includes annexes with good practices, recommendations, and examples.
• 🛠️ Mechanical design aspects covered by the code include materials, design, and fabrication, with a focus on understanding roof configurations to determine loads and design tank parts.
• 🌡️ Fixed roof tanks are suitable for non-volatile liquids and are the most common in industry, while floating roofs are used for volatile products to minimize evaporation.
• 🏭 Different roof types include conical, dome, and umbrella types, each with specific configurations and suitable for different tank sizes and fluid types.
• 🔄 Floating roofs come in two types: external, which rests on the liquid and is exposed to the environment, and internal, which is not in direct contact with solar radiation and reduces product contamination.
• ⚖️ The design of storage tanks must consider various loads, including operating weight of the fluid, seismic loads, and wind pressure, to ensure structural integrity and safety.
• 🛡️ Material selection for tanks is guided by best practices, client specifications, and metallurgy specialists, with carbon steel, stainless steel, and aluminum being common choices.

Q & A

What is the primary purpose of above ground storage tanks?

Above ground storage tanks are primarily used to store large quantities of various commodities for later use, sale, or further processing.

What types of products are commonly stored in above ground storage tanks?

Products commonly stored include crude oil and its derivatives, butane, propane, LPG, solvents, water, and more.

What are the main characteristics of above ground storage tanks?

They are a buffer between different process stages, easy to build, operate at atmospheric or near atmospheric conditions, and are generally built in situ.

Why are design codes important for storage tanks?

Design codes are important to avoid disasters affecting humans and include a range of experiences and good practices, stating minimum requirements for design, fabrication, material selection, inspection, and installation.

What are the specific requirements for tanks designed with the API 653 code?

Tanks must store only liquid fluids, have bottoms supported by sand, gravel, or concrete, maintain internal pressure below 17 kilopascals, and operate at temperatures below 93 degrees Celsius, or up to 260 degrees if Annex M requirements are met.

What is the difference between atmospheric and low-pressure tanks as defined by the API 650 code?

Atmospheric or low-pressure tanks, as defined by the API 650 code, are those that can only operate with internal pressures below 17 kilopascals.

What are the main sections covered by the mandatory requirements in the API 650 code?

The mandatory requirements are divided into 10 sections covering the complete fabrication and installation cycle of a tank, with the most relevant parts being materials, design, and fabrication.

What are the different types of tank roofs mentioned in the script and how do they differ?

The different types of tank roofs include fixed roofs (cone type, dome type, umbrella type), self-supporting roofs, and supported roofs. Fixed roofs are used for non-volatile liquids, while self-supporting roofs are capable of supporting themselves without any structural element, and supported roofs use a structure to support the roof plates.

What is a floating roof and how does it function?

A floating roof is a circular metal structure with pontoons that allow it to float on the liquid in an open or closed tank, reducing evaporation losses and preventing product contamination.

What are the considerations for selecting a type of storage tank?

Considerations for selecting a type of storage tank include product losses, mainly due to evaporation, and the selection of the roof type, which is crucial from a mechanical design point of view to determine the loads to be supported.

What are the design conditions that need to be defined for a satisfactory design of storage tanks?

Design conditions include ambient temperature or fluid temperature, internal or external loadings, liquid level, corrosion allowance, external requirements like wind, seismic or snow loads, capacity, diameter, height, and fabrication requirements.