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Clean energy recovery from biomass waste & residues (BIOWARE)

Exploitable results

The focus of this work-package is the techno- and socio economic assessment of biomass and biowastes co-combustion with coal in power plants from 2-100 MWe. Compliance of the novel gas cleaning technology with EU directives and other relevant environmental legislation will be made. The results from the work will be: - Modular approach to the assessment of conventional gas cleaning technologies in biomass and wastes combustion, allowing a range of gas cleaning systems to be evaluated both technically and economically up to 100 MWth. - Costs of electricity for biomass and wastes co-combustion with coal up to 100MWth with a variety of gas cleaning and pollutant options evaluated for particulates, NOx, SOx, HCl and CO. - Assessment of cost reductions, emissions compliance and benefits of the novel systems on electricity production costs. - Overall system efficiencies will be calculated from the WP1-5 and compared with conventional systems for gas cleaning unit operations. The results of the techno-economic assessment will allow the cost reduction potential, waste reducion and process improvements to be clearly quantified. It is expected that for particular fuels, which do not have unusual contaminants that a single step combined particle/pollutant removal system will have a significant impact on the installed capital costs of the system and allow retrofitting of existing installations. The techno-economic assessment will be accompanied by a socio-economic assessment to see whether manpower requirements are affected and ensure that emissions are lower and that the environmental advantages of the technology are highlighted.
Leather waste is easier to ignite and to burn than coal due to the high volatile matter and the combustion is expected to be fast and difficult to control. Besides, the fuel has unusually high nitrogen content (14.1% d.b.) because of its origin. Also the presence of sulphur (2%) is important. Finally, The presence of chromium makes it necessary to study the combustion conditions to prevent Cr(VI) formation. As it is well know, fluidised bed technology permits the use a sorbent for the reduction of SO2 emissions, however in the case of leather wastes when limestone is used for reducing SO2 emissions, Cr (VI) is present in the flue gas. So a post combustion technology to reduce this emission must be applied. The application of the new combined dry cleaning systems improves the application of combustion of the leather wastes as a consequence of decreasing the NOx, SO2 emissions. Moreover the study of the combustion ash recycling, is important from the economical and environmental point of view. The ash from leather wastes has high chromium content. Thus the ability to recover this chromium is very important, since this element is not available in the EU and must be imported mainly from South Africa. The co-firing programs carried out in the United States and Europe have demonstrated that co-firing biomass with coal can be beneficial to the utilities as well to the environment. Co-combustion technology, however, faces some technological problems. These problems are related to the alkaline content in the ashes and chlorine content. The application of the new combined dry cleaning system improves the combustion of coal/biomass mixtures as a consequence of decreasing the particulate matter and HCl emissions. Also in the framework of this project the study of the effect of ash characteristics on the SCR and filters process could be studied.
For the leather industry the main goal of this project is to improve the efficiency of the flue gases cleaning after the treatment of leather wastes in a fluidised bed combustion boiler. Thus, the project looks for the development of a cost effective combined dry gas cleaning and particle removal system based on ceramic filter candles to minimise the main pollutants from biomass and bio waste combustion, namely SO2, HCl, NOx and fly ash particles. Waste combustion plants are not a new technology in the Energetic European map and also not an extended technology, mainly because society regrets secondary effects of combustion processes: atmospheric pollutants. The filtration system developed in this project will result in lower capital investment, maintenance and running costs than conventional multi-step flue gas cleaning systems for small to medium scale waste combustion plants. As an expected project result, partners will disseminate the technology developed and benefits that represents the new and ecologic process for the flue gas cleaning among footwear and tannery industries in the European Union, demonstrating that well-carried leather wastes combustion can be an advantageous process in clean-energy production, apart from the economic benefit obtained of the leather waste, which nowadays is usually dumped.