Substitute
natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
(SNG), or synthetic natural gas, is a fuel gas (predominantly
methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...
, CH
4) that can be produced from
fossil fuels such as
lignite coal
Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat ...
,
oil shale
Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitut ...
, or from
biofuels (when it is named
bio-SNG) or using electricity with
power-to-gas
Power-to-gas (often abbreviated P2G) is a technology that uses electric power to produce a gaseous fuel. When using surplus power from wind generation, the concept is sometimes called windgas.
Most P2G systems use electrolysis to produce hydrogen ...
systems.
SNG in the form of
LNG or
CNG can be used in road, rail, air and marine transport vehicles as a substitute for costly diesel, petrol, etc. The
carbon footprint of SNG derived from coal is comparable to petroleum products. Bio-SNG has a much smaller carbon footprint when compared to petroleum products.
LPG can also be produced by synthesising SNG with partial reverse
hydrogenation
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organ ...
at high pressure and low temperature. LPG is more easily transportable than SNG, more suitable as fuel in two wheeler or smaller
HP vehicles /engines and also fetches higher price in international market due to short supply.
Renewable electrical energy can also be used to create SNG (methane) via for example electrolysis of water or via a PEM fuel cell in reverse to create hydrogen which is then reacted with from for example CSS/U Utilisation in the
Sabatier reaction.
: + 4H
2 → CH
4 + 2H
2O
Distribution
It is advantageous to distribute SNG and bio-SNG together with natural gas in a gas grid. In this way, the production of renewable gas can be phased in at the same rate as the production capacity is increased. The gas market and infrastructure the natural gas has contributed with is a condition for large scale introduction of renewable biomethane produced through anaerobic digestion (biogas) or gasification and methanation bio-SNG.
Projects
The
Great Plains Synfuels Plant injects approximately 4.1 million m
3/day of SNG from lignite coal into the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
national gas grid. The production process of SNG at the Great Plains plant involves
gasification, gas cleaning, shift, and
methanation
Methanation is the conversion of carbon monoxide and carbon dioxide (COx) to methane (CH4) through hydrogenation. The methanation reactions of COx were first discovered by Sabatier and Senderens in 1902.
CO''x'' methanation has many practical ap ...
. China is constructing nearly 30 nos massive SNG production plants from coal / lignite with aggregate annual capacity of 120 billion standard cubic meters of SNG.
See also
*
Landfill gas
*
Renewable natural gas
*
Oil shale gas Oil shale gas (also: retort gas or retorting gas) is a synthetic non-condensable gas mixture (syngas) produced by oil shale thermal processing (pyrolysis). Although often referred to as shale gas, it differs from the natural gas produced from shale ...
*
Power to gas
Power-to-gas (often abbreviated P2G) is a technology that uses electric power to produce a gaseous fuel. When using surplus power from wind generation, the concept is sometimes called windgas.
Most P2G systems use electrolysis to produce hydrogen ...
References
External links
SGC Rapport 187 Substitute natural gas from biomass gasificationSGC-rapport on gasification and methanation{{fuel gas
Natural gas
Synthetic fuel technologies