Shell cleans up with coal

Two of the world’s biggest mining and energy groups joined forces last week in an attempt to capitalise on the emerging area of clean coal technology.

Shell and Anglo American aim to maximise the commercial benefits from the fast-growing field by taking joint stakes in coal conversion projects, combining Anglo American’s extensive coal reserves and mining capabilities with Shell’s leading-edge technologies.

The aim is to extract, gasify then convert coal into, among others, hydrogen and liquid hydrocarbons. Burning the synthesis gas generated by coal gasification emits far lower quantities of greenhouse gases and pollutants than standard coal burning and is the cleanest way to harness its energy potential.

Coal gasification is the partial combustion of carbonaceous materials such as coal and petroleum coke and requires only 20-30 per cent of the oxygen needed for complete combustion.

The primary product is syngas, a mixture of carbon monoxide and hydrogen, which still contains 80 per cent of the original energy in the coal. Another 15 per cent of energy is recovered in the form of steam. Energy losses in total as a result of gasification are just five per cent.

As well as being as clean to burn as natural gas, Syngas can also be used in combined power plants (operating on both gas and steam turbines), which are more efficient than conventional coal-fired power stations, and can be used directly as a fuel to generate heat, steam and electricity.

Syngas can also be used to manufacture pure hydrogen or synthesise ammonia, methanol and their derivatives.

None of the coal’s constituents are wasted; sulphur is recovered and sold as feedstock to the chemical industry, while ash is recovered as clean slag and used to make ceramic tiles and bricks.

The two partners hope to incorporate Anglo American’s Monash Energy Project, based in Australia, into the alliance. Monash Energy is applying advanced drying and gasification technologies to brown coal to produce large volumes of ultra-clean synthetic diesel.

This enables separation of a concentrated CO2 stream that can be transported to injection wells in deep underground geological formations for secure storage. Central to the project is a large-scale commercial drying plant in Victoria‘s LatrobeValley, which dries and gasifies coal from the Monash mine for conversion into transport fuels.

Anglo American chief executive Tony Trahar said: ‘The ability of Anglo American and Shell to form a clean coal energy alliance,with the potential to develop multiple projects, will create a sustainable competitive advantage, while creating value for the shareholders of both partners.’