Flammable liquids are substances that can catch fire easily when exposed to heat, sparks or flames. They are widely used in various industries, such as chemical, pharmaceutical, oil and gas, and transportation. However, transporting flammable liquids poses significant challenges and risks, as they may cause fire, explosion, leakage, or environmental pollution if not handled properly. Therefore, it is essential to choose the appropriate containers and methods for transporting flammable liquids safely and efficiently.
In this article, we will focus on two common types of flammable liquids: butane and isobutane. Butane and isobutane are both liquid hydrocarbons, belonging to the third class of dangerous goods². They are mainly used as fuels, refrigerants, propellants, and solvents. They have similar chemical properties, but different molecular structures. Butane has a straight-chain structure, while isobutane has a branched-chain structure. This difference affects their physical properties, such as boiling point, vapor pressure, and density.
We will introduce the characteristics and applications of butane and isobutane, and explain how they can be transported using ISOTank containers, which are specially designed for carrying liquid or gas cargoes. We will also compare the advantages and disadvantages of different types of ISOTank containers, and provide some tips and suggestions for choosing and using them.
What are Butane and Isobutane?
Butane and isobutane are both colorless and odorless liquids at room temperature and atmospheric pressure. They have low viscosity and high volatility, meaning that they can easily flow and evaporate. They are also highly flammable and explosive, meaning that they can ignite and explode when mixed with air in certain proportions. They have low toxicity and low corrosivity, meaning that they have little harmful effects on human health and metal materials.
Butane and isobutane have many industrial and domestic applications, such as:
- As fuels for cooking, heating, and camping. They are often stored in pressurized cylinders or cartridges, and burned in stoves, heaters, or lanterns.
- As refrigerants for cooling and freezing. They are often used in refrigerators, freezers, air conditioners, and heat pumps, as they have good thermodynamic properties and low environmental impact.
- As propellants for aerosols and foams. They are often used in spray cans, such as hairsprays, deodorants, paints, and whipped creams, as they can create high pressure and fine mist.
- As solvents for extraction and purification. They are often used in chemical processes, such as oil refining, natural gas processing, and pharmaceutical manufacturing, as they can dissolve and separate various substances.
How to Transport Butane and Isobutane?
Butane and isobutane can be transported by various modes, such as pipelines, trucks, trains, ships, and planes. However, each mode has its own limitations and challenges, such as capacity, cost, safety, and environmental impact. Therefore, it is important to choose the most suitable mode for different situations and destinations.
One of the most common and convenient modes for transporting butane and isobutane is using ISOTank containers, which are standardized and modularized containers that can carry liquid or gas cargoes. ISOTank containers are made of stainless steel, and have a cylindrical tank inside a rectangular frame. They have various valves, fittings, and accessories, such as heating, insulation, pressure relief, and inert gas systems, to ensure the safety and quality of the cargoes. They can be easily loaded and unloaded, and transferred between different modes, such as trucks, trains, ships, and planes, without changing the containers.
ISOTank containers are classified into different types according to the International Maritime Dangerous Goods (IMDG) Code, which regulates the transportation of dangerous goods by sea. The types of ISOTank containers are based on the design pressure, the minimum and maximum temperatures, and the test pressure of the containers. The main types of ISOTank containers are:
- IMO 1: for transporting substances with a vapor pressure of less than 1.5 bar at 50°C, and a test pressure of at least 6 bar.
- IMO 2: for transporting substances with a vapor pressure of less than 4 bar at 50°C, and a test pressure of at least 4 bar.
- IMO 5: for transporting refrigerated liquefied gases, such as ammonia, carbon dioxide, and nitrous oxide, with a test pressure of at least 1.8 bar.
- IMO 7: for transporting cryogenic liquefied gases, such as liquid nitrogen, oxygen, and helium, with a test pressure of at least 10 bar.
According to the IMDG Code, butane and isobutane should be transported using IMO 1 or IMO 2 ISOTank containers, as they have a vapor pressure of about 2.3 bar and 3.1 bar at 50°C, respectively³. These types of ISOTank containers have the following features:
- The tank is made of stainless steel, which can resist the corrosion and leakage of butane and isobutane.
- The tank has a steam or electric heating system, which can maintain the suitable temperature and pressure of butane and isobutane.
- The tank has an inert gas protection system, which can prevent the self-ignition or explosion of butane and isobutane.
- The tank has a pressure relief system, which can avoid the overpressure or vacuum of butane and isobutane.
- The tank has a protective and lifting frame, which can facilitate the multimodal transportation of butane and isobutane.