Liquefied natural gas (LNG) and compressed natural gas (CNG) are increasingly becoming a normal fuel for vehicles to not only reduce emissions, but reduce fuel cost. An important piece of infrastructure needed to excel this movement is an LCNG fueling station. An LCNG station is a combination LNG and CNG station that uses LNG supplied by tanker trucks and stored onsite for fueling use. In order to use the LNG as a fuel, the liquid first need to be pumped through a saturation coil, typically an ambient type vaporizer, to condition the LNG at saturated temperatures. Once conditioned, the LNG is pumped to a dispenser and into the vehicle. When CNG is needed, the LNG is pumped to high pressure, sent through an ambient type vaporizer to be warmed and sent to a storage cylinder bank to await dispensing.
As the global demand of natural gas increases, the nations who have abundance of gas need to be able to ship to nations that are limited in natural gas resources. Since it is more economical to ship in liquid form, there are an increase of LNG terminals worldwide. LNG terminals are used for both importing and exporting LNG. Export terminals, like the Sabine Pass LNG Terminal in Louisiana, pull natural gas out of the existing pipeline and liquefy onsite into large storage containers. The liquid is then loaded onto a ship for transportation. On the receiving end, an import terminal has storage tanks ready for the arriving liquid to be stored until needed. The liquid is then re-gasified by heat exchangers (vaporizers) and sent into a natural gas pipeline. LNG vaporizers, BOG heaters and Flare Vaporizers are among the large amount of equipment needed onsite at each terminal. Terminals do not need to be land based. A need for relocating a single terminal to different nations is giving rise to shipboard FSRU (Floating Storage and Regasification Units). These have all the basic components of a land based terminal with the ability to relocate.
Marine vessels typically use a variety of fuel oils which are generally residual products of crude oil refining. The problem with this type of fuel is that is generates are variety of harmful pollutants. One way to reduce the pollutants is by using LNG as a second fuel source and substituting a large percentage of the fuel oil. The duel fuel engine market is growing as existing ships are converting and new ships are utilizing the technology. In these systems, LNG is stored on the ship and converted to natural gas by pumping and vaporizing before being injected into the engine. Because LNG is being loaded on the ships, it gives rise to LNG transportation and bunkering on the docks.
LNG peak shaving is a system that aims to reduce price volatility and meet increased demands of natural gas. LNG peak shaving is the operation of storing LNG to be used to during periods of increased natural gas pipeline consumption. During extreme cold or extreme heat, the demand of natural gas increases to feed heating systems or power generation systems respectively. LNG peak shaving plants operate during these high demand (“peak”) periods to ensure the requirements of consumption are met. Peak shaving plants purchase natural gas during off-seasons and liquefy into onsite storage containers. When a peak demand is required, the LNG is re-gasified and injected into the pipeline system.
As the trucking industry continuous to use LNG and CNG as fuel source, the rail and mining sectors are starting to make the same conversion. Rail accounts for nearly 40% of freight ton-miles in America and can account for a large potential for LNG as a fueling source. There are few rail cars running on LNG at the moment and will continue to increase as the infrastructure grows. In the mining sector, more generators are moving to run on natural gas. Due to the remote locations, virtual pipelines can be used to provide natural gas onsite (see virtual pipelines for explanation). With virtual pipelines present, LNG is available to be used as a fuel for mining trucks. This is another way to reduce emissions on large engine vehicles and extensive testing have been done in recent years to achieve this goal.
When natural gas pipelines are unavailable due to a site’s remote location, an LNG virtual pipeline system can be used to supply the site with natural gas by offloading and re-gasifying LNG. Virtual pipelines consist of an LNG storage (either a transport trailer or onsite tank), a vaporization system and control system to monitor gas flows and safety concerns. Asphalt plants, mining operations, and boiler/furnace fueling are all applications that have a potential for an LNG virtual pipeline systems. If a permanent installation is required, an offload pumping system can be added to remove the LNG from ISO containers into onsite storage. Many virtual pipeline systems are mobile, allowing equipment owners to contract temporary projects and follow LNG transport trailer to any site accessible by road. Drill or frack sites utilize mobile virtual pipeline systems to feed natural gas generators for onsite power.