27 technologies to produce lower carbon fuels from “second chance carbon” — and its practicioners. Who’s doing what, where, when, why and how?

Fuels produced from natural gas

Case example:

Siluria (USA) (TRL 6-7 )
Silura’s OCM catalyst alsallows for co-feeding of ethane alongside  methane tproduce ethylene. Siluria has developed a catalytic process for the conversion of ethylene togasoline. Siluria has a demonstration plant in Texas, which began operation in 2015. It is operated by Braskem and can produce approximately 350 t/year of ethylene.

Liquefied Natural Gas by cooling

Natural gas is cleaned and purified and then cooled until it reaches its liquid phase in large scale commercial processes (TRL 9), which are operating globally today. The main purpose of this practice is tenable shipping via tanker over long distances, but LNG can also be used as a transport fuel in vehicles, either in dual-fuel engines or dedicated gas engines. LNG vehicles can generally travel further than CNG vehicles before needing trefuel, therefore LNG is often favoured for larger HGVs and for use in ships.

Compressed Natural Gas (CNG) by compression

The compression of natural gas is practiced globally at TRL 9, and CNG can be used either in dual-fuel or dedicated gas engines. As CNG vehicles generally have a smaller range than LNG vehicles, priority markets tend tbe smaller road vehicles and ‘back tdepot’ type operations.

Liquefied Petroleum Gas (LPG) by separation

Natural gas liquids, alsknown as condensates, are produced alongside methane when natural gas is extracted. Natural gas liquids make up between 1% and 10% of the unprocessed natural gas stream. Propane, butane and isobutane are separated from this stream and sold as LPG (TRL 9). Currently LPG is used in around 150,000 UK vehicles, all of which can run on both LPG and conventional gasoline.

There is a small cost associated with conversion of the engine to run on LPG, generally between £1000 and £2000. As well as road transport vehicles, around a third of all fork lift trucks in the UK alsrun on LPG. LPG is subject to lower fuel duties in the UK than conventional gasoline or diesel, and is therefore cheaper at the pump, although this cost saving is partially offset by the additional fuel volume that is required for an equivalent mileage. Nevertheless LPG remains a cheaper fuel option than gasoline or diesel at present.

Gasoline by oxidative coupling of methane and catalytic conversion of ethylene to liquids

In oxidative coupling of methane (OCM), methane reacts with oxygen over a catalyst in an exothermic reaction tform ethylene, water and heat. The ethylene is an intermediate product that has many uses in the chemicals industry, but it can also be oligomerised using another catalytic process tproduce liquids such as gasoline.

Diesel, jet and gasoline by catalytic synthesis of syngas

The gas-to-liquid process involves conversion of natural gas to syngas by sulfur removal followed by partial oxidation, steam reforming or autothermal reforming. This is then followed by Fischer-Tropsch synthesis, which is a catalytic process that can be tailored tproduce fuel products such as diesel, jet fuel, naphtha and other products such as waxes from syngas. Available from: LPG, biopropane and low-carbon transport  GtL plants with capacities of 430,000 – over 22,250,000 L/day are located in Malaysia (Shell), Qatar (Shell, Sasol/Chevron), South Africa (Sasol) and Nigeria (Chevron/Sasol).

Case study companies:

Velocys (TRL 7)

Focusing on smaller scale plant which allows for targeting stranded  natural gas and/or landfill gas. It is the possibility of designing smaller units that might make processing stranded natural gas economically viable that is particularly relevant in the context of this report.  Demonstration plant in Oklahoma, USA, is operating, processing landfill and natural gas intFT diesel, naphtha and waxes.

Methanol by catalytic synthesis of syngas

Methanol is an important primary chemical product, which can alsbe used directly as a fuel (blended with gasoline) or it can be converted tdimethyl ether (DME) for combustion in diesel engines or tgasoline via the ExxonMobil methanol-to-gasoline (MTG) process, or tmethyl-tert-butyl-ether (MTBE) for combustion in gasoline engines.

It is produced by converting the natural gas ta syngas by sulfur removal followed by partial oxidation, steam reforming or autothermal reforming. Catalysts are then used tpromote the methanol synthesis reactions. Methanol production from natural gas-derived syngas is a commercial technology (TRL 9) with plants globally yielding 2,000 – 5,000 t/d.

More hydrogen is produced in the syngas than is used in the production of methanol. It is possible tincrease the yield of methanol by injecting additional CO2 intthe vessel treact with this ‘excess’ hydrogen. This is practiced by some methanol producers.

Hydrogen by water-gas-shift conversion of syngas

Natural gas can be converted tsyngas by partial oxidation, steam methane reforming or autothermal reforming. This syngas can subsequently be converted inthydrogen via the water-gas-shift reaction. This is a very common process which is used today tproduce 95% of the hydrogen used in the USA and is therefore at TRL 9.5 This is how the hydrogen used in HV production is usually produced.