LNG is expected to become a key source of energy in the coming decades. It is the cleanest fossil fuel and is relatively abundant. The market for LNG is expanding at a time of peak global energy demand.
The storage of LNG is the most important issue when applying this energy source. Next we will learn what exactly LNG is, and the several types of its storage equipment.
Liquefied natural gas (also known as LNG) is natural gas that is cooled to a liquid state for ease of storage and transportation. When the temperature is lowered to approximately -260 degrees Fahrenheit, LNG can become 600 times smaller than its gaseous state through a liquefaction process using a cryogenic heat exchanger. This greatly saves storage and transportation space, facilitates its management, and is one of the main advantages of LNG.
Thanks to liquefaction technology, long-distance transportation of natural gas energy (e.g. import and export between countries) has become easier. LNG can be kept in tank containers and transported by LNG trailers or sailing ships without the use of natural gas pipelines that are difficult to build over long distances.
The demand for LNG has been growing over the past few years and is expected to continue to grow.
The main advantages of liquefied natural gas include:
-Generally available on a global scale compared to other fossil fuels
-Ease of distribution and storage capacity to easily respond to changing demand patterns.
-Cleaner combustion products compared to other fossil fuels, making it a more environmentally friendly option.
LNG is a clear, non-corrosive liquid, less dense than water, and composed of at least 85% methane. Based on these characteristics, the storage methods and equipment for LNG have been an important concern in the industry.
Today, most of the LNG storage is done in tanks. There are three main types of storage containment systems for LNG tanks: single, double or full containment.
A single containment system consists of an inner and outer container. The inner vessel is liquid-tight and designed to contain liquid natural gas. The outer vessel is designed for the vapor pressure of the product. It protects the insulation, but cannot contain the liquid. Therefore, when the inner vessel ruptures, the single storage system leaks.
The double storage system has a liquid and vapor sealed main tank system. This system is built into a liquid-tight secondary vessel. This secondary liquid vessel is liquid sealed, but not vapor sealed.
Finally, a fully enclosed system consists of a liquid-sealed primary vessel and a liquid- and vapor-sealed secondary vessel. Both are capable of holding product independently. The secondary vessel controls vapor release in the event of a primary product leak. Another design feature of this containment system is the Thermal Corner Protection (TCP). The TCP protects the bottom of the outer tank where it meets the wall. In the event of a primary vessel leak, the TCP provides liquid tightness and thermally isolates the joint from the cold liquid.
Storage tank systems are an important part of the LNG infrastructure. Although they are a small component of the overall LNG infrastructure, selecting the storage tank and containment configuration for an LNG facility is the first step in the design and engineering process.
CIMC ENRIC is a specialist in LNG transportation and infrastructure. Whether you need LNG ISO containers, trailers, or above ground storage tanks, we have the most professional and reliable products. Contact us today to learn more.