Awards Book

Towards Zero Gas Emission (pdf 1.2Mb)

Bristol and South West Section

South Wales Section

Towards Zero Gas Emission

A distinguished metallurgist, originally from Australia, Professor Noel Warner received the Robert Horne award from Diane Brown, Chair of the SCI Awards Committee, at a Joint Meeting of the Bristol and South West and the South Wales Sections.

Prof Warner then presented the 2004 Robert Horne lecture, 'Towards Zero Gas Emission', in which he outlined novel technology for the production of iron and steel with very low emissions, of carbon dioxide in particular. Such technology should also be applicable to the equally efficient production of non-ferrous metals. Click here for the full presentation (pdf 1.2Mb)

The lecture opened with a brief resume of the urgent necessity to establish the zero emission principle in relation to carbon dioxide and other traditional 'smoke stack' emissions from metallurgical processing such as sulphur dioxide, nitrogen oxides and toxic particulates. Prof Warner estimated that present energy sources such as fossil fuels (oil, coal and gas), nuclear-based power, hydrogen power, and other renewables would become scarce by 2020. Sequestration might add 15 years to this but costs would be similar to renewables.

Hydrogen is attractive technically, but using current technology would be too expensive as a prime source for electricity generation. Displacement of methane from coal deposits, followed by partial oxidation to hydrogen and carbon dioxide is a possibility using the Texaco non-catalytic process, but removal of toxic mercury is a major problem.

Turning now to the specific emission problems of iron and steel processes, the industry consumes approximately 350 million tonnes of coke per annum and currently accounts for approximately 6% of world fossil fuel consumption, energy costs representing 15-25% of total steel manufacturing costs. Including non-ferrous processing, the metallurgical industries emit only about 10% of man-made carbon dioxide emissions world-wide, but this quantity must be eliminated, or at least substantially reduced, together with that arising from fossil-fuel power generation (about a third of the overall total) to ameliorate the global
warming problem.

Any new reactor concept must eliminate the extremely rapid reactions taking place just below the molten iron/steel surface known as Bessemer 'volcanoes'. Aided by the use of electro-magnetic levitation techniques to study the kinetics of the underlying reactions, Warner feels that, after 80 not wholly-successful attempts to eliminate these 'volcanoes' he is now near to success, and has achieved very low concentrations of emitted carbon dioxide.

For the vacuum degassing of steel, the group at Birmingham led by Prof Warner has devised a new type of reactor, termed Generic Melt Circulation Technology, which provides oxidising conditions on one side of the circulating metal and reducing conditions on the other. These clean surfaces have achieved 100% post-combustion efficiency.

Large scale experiments at Birmingham with copper matte have shown this system to work successfully for several hours, but conclusive trials await further funding.

Professor Warner foresees the further development of this system to one converting virgin ore and/or scrap material, pulverised coal and lime flux into iron, and then primary and secondary steel including ultra-low carbon steels. Probably three separate but linked reactor loops would be required contained in a steel, rather than a refractory-lined vessel. At present he sees no reason why such a system should not be extended to non-ferrous smelting, all processes achieving virtually zero-gas emissions.

The evening ended with a dinner attended by 42 people, including seven colleagues who had worked with Prof Warner at Avonmouth between 1969 and 1971.