Drying brown coal The adoption of suitable drying technologies could enable brown coal to be exported and compete directly in black coal markets as an energy and feedstock resource. Potential coal derivative products Solid fuel products In its raw form, brown coal can be used for boiler fuel in power generation. Drying technologies can transform the product into high energy briquettes and pellets that may compete with black coal as an exportable fuel.
Chars and cokes may potentially be derived from brown coal for pyrometallurgical applications, to produce reductants and carbonising chemicals and as a general carbon source for other applications. Calcium loaded char can be used in water and waste treatment and as an ion-exchange medium. Brown coal can also be refined into a purer form of carbon for use in production of a number of carbon products including carbon fibres, carbon anodes, activated carbons, filter aids, pigments, graphite lubricants and conductors and formed carbon materials.
Gaseous products Gasification can be used to convert solid coal into a gaseous feedstock, which can be used to make a range of other products. Gasification produces synthesis gas or syngas, a mixture of mostly carbon monoxide and hydrogen. The process can also help with separation of carbon dioxide for use of sequestration. Victoria has had a long history of brown coal gasification. It provided town gas in the Latrobe Valley before natural gas from Bass Strait became available in the 1960s. Liquid products Liquid products from coal can be produced either from syngas via gasification or by the direct liquefaction of brown coal.
Gasification can produce liquid fuel products such as diesel, methanol, fuel gasoline blends, and high octane gasoline extenders. Liquefaction generally produces lower quality products, such as synthetic crude oil. Further processing may be used to produce fuel oil, diesel, motor fuel blends, kerosene and heating oil. Non-fuel products may also be produced including solvents, polymers, surfactants, lubricants and a suite of other carbon-based chemicals. Waxes, resins and polymers A range of waxes may be produced using products derived from brown coal, as well as phenolic resins and plastics, composites, low strength structural and building materials. Agricultural products
Raw brown coal can be used as a soil conditioner by providing a source of humic acids for potting mixtures and market gardens and as an ad-mixture to other fertilisers and soil conditioners. Syngas manufactured from coal can be used to produce ammonia, the key pre-cursor to nitrogenous fertilisers such as urea. At present these fertilisers are more commonly made from oil and natural gas based feedstocks.
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The shift in coal’s economics have led innovators to look for new uses for the mineral, and Randy Atkins, CEO of Ramaco Carbon in Sheridan, is among those leading the push locally. Atkins said that while coal is best known today as fuel for power plants and as a reducing agent in the steelmaking process, it was once believed to have potential far beyond just those uses.
“There used to be a thing called the ‘coal tree’ in the early part of the 20th century. In Germany and even the U.S. they had these tree drawings, it was all the various things you could make from coal,” Atkins said. “We were making all sorts of chemical products, drugs, cosmetics, you name it; all from coal.”
That changed following the invention of catalytic cracking, the process by which crude oil is broken up into smaller molecules that are then made into refined products like gasoline, plastics, and a myriad of other uses. From then on, Atkins said, exploration of coal’s alternative uses effectively evaporated.
“I wouldn’t even say it was left by the wayside, it’s just all the technology advanced through the use of petroleum,” he said. “If you go back to the ’80s there were a couple attempts to make coal to fuels, and that involved making what looked like a refinery for processing coal. … But it’s really been the last three years that some of this stuff has started to come together in ways that began to make the argument that coal needs to be given a second look for uses beyond combustion.”
Since coal is primarily composed of carbon, Atkins and like-minded researchers have been looking at coal’s potential as a source for carbon fiber, a high-strength, low-weight material used primarily in aircraft and the aerospace field, but with the potential for many other uses.
“What we’re trying to do with carbon fiber is to make it dramatically less expensive than today’s use of carbon fiber from petroleum,” Atkins said. “Right now prices are $25 to $45 a pound for (carbon fiber) precursor made from petroleum. We think we can get that down to five bucks.”
In fact, Atkins, along with other members of the National Coal Council, contributed to a report published earlier this spring at the behest of the Department of Energy, “Coal in a New Carbon Age: Powering a Wave of Innovation in Advanced Products and Manufacturing.”