ALM UNDP

Summary:

Carbon dioxide capture and storage (CCS) is considered as a very promising potential technology to mitigate climate change, it involves the separation of CO2 from industrial and energy-related sources, transport to a storage location and long-term isolation from the atmosphere. Renewable CCS (RCCS) from biomass is possible and presents the additional advantage of converting the overall CO2 emission balance from the process into a negative one when deployed in an ethanol producing plant.

This project proposes the development of RCCS from CO2 emitted from sugar fermentation in a demonstration plant at a sugar/ethanol mill in Sao Paulo state. During fermentation, gaseous is released in 100% concentration and free of other gases (Nitrogen, CO) and impurities (e.g. sulphur, hydrocarbons, and acids) for underground storage. Thus, this project aims to store already clean CO2 emissions from sugar fermentation underground in available saline formations.

This project is essentially storage of CO2 since the capture, which is a difficult step performed for CCS from fossil fuel combustion, is not necessary in the sugar fermentation process given the high purity of the CO2 generated and the fact that it flows at almost room temperature from the existing venting port of the fermentation vessel. Another advantage of this process is that it can be replicated in the future for all sugar fermentation process based on corn, sugar beet, cassava or wheat. In addition, the improvement of the proposed technology may be useful for any other CCS projects, even those with fossil fuel gases.

RCCS from sugar fermentation can make a significant contribution to the greenhouse gas (GHG) balance of ethanol-based fuels since the amount of CO2 produced during fermentation is almost the same as ethanol in a weight basis. Therefore, in the production of 1 ton of ethanol, almost 1 ton of CO2 can be captured. Sugar mills operating with sugar cane feedstock and generating electricity with very efficient boilers (100 bars or more) should be able to yield negative GHGs emissions by the application of RCCS.