Changing the way we think about brown coal

In a post a few months back, i talked about a few clean coal technologies coming out of Australia, and a fairly broad overview of the tech areas. I recently met with Bill Stevens from Latrobe Lignite Developments (LLD) who gave me some more detailed insight into the potential of brown coal as an energy and carbon product resource.

Brown coal (Lignite) is essentially made up of around 60% water, 20% petrochemical volatiles and 20% carbon base. The high water content and low carbon content traditionally has meant that this form of coal is primarily used for steam-electricity energy production. The large amounts of water in the fuel mean that a large amount of heat is wasted in heating this water up, and loosing it into the atmosphere as water vapour.

Prior to my discussion my understanding was that the brown coal discussion essentially was that you can improve the efficiencies of burning coal to reduce CO2 emissions through removing water content, and improve the efficiency of energy generation. However this has its econimic and emission reduction problems.

Efforts to reduce the water content of lignite have been either to chemically separate it, mechanically squeeze it, or dry it through using byproduct heat or spread the material out in the sun. The challenge is all these approaches required energy, as a result any real greenhouse benefit is reduced through all the toil involved.

Also the power stations in the Latrobe Valley in Victoria, Australia are designed to be as efficient as possible to burn brown coal, not dry brown coal. Hence in reality you could partially mix some dry coal into the feedstock for the generators, but probably only about 5%. Thus you need a new power station if you want to burn the new dry brown coal.

LLD has produced a technology which takes advantages of a few other factors in the economic equation around brown coal, namely carbon products and water. First the stats:

  • The prices a, la trobe valley brown coal costs about A$5 and Antracite and coking coal costs about A$50
  • New energy generation emissions limits: Brown coal must generate at most 1.2T C02 per MW, black coal power plant must generate at most 0.9T C02 per MW. In comparison a gas plant must generate at most 0.5T C02 per MW.
  • Water: for every 2000T per hour of brown coal at Loyang (Latrobe valley) power station, over 12million T of water is removed annually from the local river.

LLDs tech uses the above economic and emission factors to turn the traditional generation mechanism around. The tech drys the brown coal recovering the water, removes the volatile component for energy generation, and produces high quality carbon for steel production or other carbon products.

Thus a A$5 feedstock produces a A$50 value product at around $15 cost, Produces volatiles that can produce energy at 0.5T Co2 per megawatt and for every Tonne of Coal returns around 660kg of water.

By way of example an existing 1000T per hour brown coal plant that costs around A$2B to build produces 1000MW for around A$130m annual rev

A 3000T per hour LLD tech and gas power plant that can produce the same amount of power and costs less to build can return in carbon products can produce over A$1B in total revenues a year due to carbon products, and returns over 20million T of water to the local area per year.

Given that China and India are requiring coking coal for their steel industies, this can potentially provide for this, bearing in mind ideally we would like to capture the emissions from these furnaces some how.

Now if plants like this were instituted in Victoria for our power generation, the interesting thing is this could completely provide for the emission reductions that Australia needs under the Kyoto Protocol. Makes you think.

Nick Bruse is the General Manager of Clean Technology AustralAsia Pty Ltd, the organiser of the AustralAsian Cleantech Forums and Dealer Forums, and the leading advocate of Cleantech in Australia. Nick does a weekly blog column on Cleantechblog profiling innovative Australian cleantech, energy, water and environmental technology companies.

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