Liquified Natural Gas - LNG

Characteristics of LNG

LNG – Liquefied Natural Gas – is a clear, odorless, colorless, non-corrosive and non-toxic, cryogenic fuel which is composed primarily of methane and be stored below methane’s boiling point, -161ºC, at near atmospheric pressure. At this temperature and pressure the methane exists as a liquid. Depending on the composition of the feed gas, the volume ratio between the gaseous state and the liquid state is about 600:1. This makes LNG suitable for storage and transportation in large quantities. The heating value of LNG is estimated to a lower heating value of about 21000 MJ/m3. LNG is very efficient as energy carrier and so there are some advantages to use it.

• Environmentally friendly - methane, a dangerous greenhouse gas, is captured and processed instead of vented to the atmosphere.

• Cost-effective fuel source - processed gas powers onsite equipment or can be sold to nearby gas pipelines.

• Potential for carbon credit trading as a qualified emissions reduction.

Processes of coal mine methane (CMM) upgrade and liquefication

The properties of CMM depend on the coal bed source and the method of its recovery. They may vary over time and depend on the conditions of its extraction. The typical components of CMM include methane, carbon dioxide and nitrogen. Substances as hydrocarbons of longer chains, water vapor, oxygen, hydrogen, carbon monoxide, helium, hydrogen sulfide, chlorine hydrogen, fluoride hydrogen, ammonium and mercury may occur in smaller or trace amounts. Similarly as in the case of other mine gases e.g. natural gas, CMM requires purification before any application or processing including liquefaction in order to remove the undesired substances.