Mauritius’ leading sugar producer Omnicane has obtained the authorisation of the Environment Ministry for the development of its Carbon Burn-Out Unit at La Baraque, L’Escalier. This project could, eventually, reduce the price of the cement because the company is planning to use ashes of its thermal power plant as additive for cement.
Moreover, the group has already initiated negotiations with local cement workers whose reaction was “very positive”, according to management.
The burning of coal in grid boilers in the power plants of La Baraque and St Aubin produces fly ash and bottom ash, and these are presently buried in land cavities and depressions. Such sites are limited, and it was imperative to seek alternative modes of disposal. Various research projects have been carried out across the world on how fly ash and bottom ash might be put to good use in the construction industry.
The idea behind Omnicane’s Carbon Burn-Out (CBO) project is to burn the extra carbon in the power plants’ fly ash and bottom ash – and in the process, reduce their carbon content from 20% to 5%.
Hence, the final product obtained may advantageously be mixed with bulk cement for the construction industry, even as the process produces extra electricity and steam for Omnicane’s sugar refinery at La Baraque. “What returns from the ashes after burn-out is capable of application as additive for cement,” indicated Omnicane.
A technician from the construction sector explained that the quantity of additive in the cement will have to abide certain standards, already established by the Mauritius Standards Bureau, because when a cement contains more additive, it is less strong.
Further to a feasibility study of a CBO unit with a Thermax circulating fluidised-bed boiler in 2009, it was decided to perform a combustion test in May 2010, on a pilot plant scaled ¼ of the demonstration unit (30 t/h of steam), with two containers of 15 tonnes of coal, bottom ash and fly ash.
Besides, the group signed a collaborative-research agreement with Swiss-based construction major Holcim in December 2009 to assess the feasibility of bulk-cement blends with a CBO final product content of up to 15%.
It may be noted that Omnicane’s main activities currently include the production of refined sugar (about 150,000 tonnes per year) and the generation of energy from bagasse and coal.
Additionally, the company has ventured into property development with the ambitious Mon Trésor Airport City project, with the first link, the Holiday Inn Mauritius Airport hotel, already in place.
Earlier this year, Omnicane CEO Jacques d’Unienville outlined his vision to transform Omnicane into an integrated agro-industrial cluster over the last decade, starting with the launch of the bioethanol distillery, followed by the Carbon Burn-Out unit project.
Image (PMI Ash): The idea behind Omnicane’s Carbon Burn-Out (CBO) project is to burn the extra carbon in the power plants’ fly ash and bottom ash – and in the process, reduce their carbon content from 20% to 5%.
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