 |
 |
|
|
|
Use
of Biomass as a Fossil Fuel Replacement in Australian
Cement Kilns
Presented at the Bioenergy Australia 2003 Conference
Held 8-10 December in Sydney
by Matthew Warnken and co-authored by Damien Giurco
Cement and cement products are essential
materials in the Australian construction and building
industry of today. The cement industry in Australia
comprises Adelaide Brighton Ltd, Blue Circle Southern
Cement Ltd and Cement Australia Pty Ltd. These
three companies operate ten cement works, which
together account for 100 per cent of integrated
clinker and cement supplies in the country.
Environmental issues have taken on an increasing
importance in the Australian Cement Industry,
as evidenced by plant upgrades to improve energy
efficiency and to reduce emissions, the release
of a second Cement Industry Environment Report
and a growing uptake of alternative raw materials
and alternative fuels offering environmental benefits.
Alternative fuels that are being used by cement
kilns to replace traditional fossil fuels include
tyres, carbon anode dust & spent pot linings
from the aluminium industry, a blend of recovered
oils, dewatered sludges and grease trap emulsions
and solvent based fuel. These alternative fuels
currently account for approximately 6 per cent
of thermal energy requirements for the Australian
Cement Industry.
There are also a range of biomass-based alternative
fuels that are able to be used by cement kilns
including wood, tallow, dried biosolids, wheat
residues, rice hulls, the woody component from
composted organics, grape marc (residual skins
from winemaking) and some types of process engineered
fuel (for example, residual paper from material
recovery facilities - MRFs).
The uptake of biomass-based alternative fuels
is in its infancy, but is poised to increase in
the coming year to similar tonnages as for existing
alternative fuels. This would put biomass fuel
use at 45,000 tonnes per annum (tpa) out of a
total alternative fuel use of approximately 100,000
tpa. (However, biomass-based alternative fuels
generally provide less thermal energy per tonne
when combusted than the average for existing alternative
fuels, meaning that the 'energy delivered' difference
will be greater than the 'tonnes delivered'.)
Advantages of using biomass as a replacement fuel
include conservation of non-renewable fossil fuels,
reduction in greenhouse gas emissions by offsetting
fossil fuel use, recovery of a higher resource
value from previously wasted materials, conservation
of landfill space in some instances, a reduction
in Nitrogen Oxide (NOx), ability to utilise complementary
alternative materials owing to reduction in ash
content (coal replacement), less concerns regarding
the composition of the fuel from a technical and
community perspective (as compared against other
alternative
fuels) and an overall improved environmental performance.
Additional benefits of a financial nature in terms
of lower cost of fuel are also realised.
Barriers to the use of biomass include the capital
cost for new processing and handling equipment
(both on and off site), transport and logistics
arising from the dispersed nature of the sources
of the biomass fuel, process issues such as managing
the quality of the fuel, wear on refractory brick
linings, kiln ring build-up, lower productions
rates and changed material recipe.
As the use of biomass-based alternative fuels
is just beginning, there are still challenges
to overcome in order to harness all of the advantages
that biomass fuels have to offer the cement industry.
These include gaining a 'community licence to
operate', gaining regulatory approval and gaining
access to potential supply that achieves the right
balance of economic benefits for the fuel supplier
and user.
Overall there is a growing interest within the cement
industry regarding the use of alternative fuels
(with specific attention given to biomass-based
alternative fuels), as a means of achieving economic
and environmental goals. Biomass in particular,
has many advantages to offer the cement industry
in Australia. The use of biomass is set to increase
in the short term, provided that the technical barriers
can be overcome in an economic manner and that fossil
fuel replacement projects can gain the support of
both the community and regulators.
>>
Click here to download the conference paper
|
|
| |
|
|
|
|
