ASHES –Recycling of nutrients from residues of thermo-chemical processing of bagasse/sugar cane straw
The project “ASHES –Recycling of nutrients from residues of thermo-chemical processing of bagasse/sugar cane straw” is coordinated by the Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT in Sulzbach-Rosenberg. The project started on 1 April 2015 and the duration of the German-Brazilian research project is three years. The Federal Ministry of Education and Research (BMBF) is funding the project with two million euros. Six German institutes, four Brazilian research partners and two industrial companies are involved in the project Ashes: This includes Fraunhofer UMSICHT, the Karlsruhe Institute of Technology (KIT), the Federal Institute for Materials Research and Testing (BAM), Fraunhofer IGB, Forschungszentrum Jülich, the Cutec Institute, the Brazilian Center for Research in Energy and Materials (CNPEM), the Federal Institute of Goiás (IFG), Laboratório Nacional Agropecuario (LANAGRO) and the Universidade Federal de Goiás (UFG), as well as the companies Tecnaro and Outotec.
Dry lignocellulosic biomass (straw, bagasse) is increasingly utilized in thermochemical processes like combustion or gasification. The task of the German-Brazilian collaboration project ASHES is to improve these processes with the aim to increase energy efficiency and to enable the recycling of process ashes to close the material cycles. For this purpose low-pollution ashes, which contain silica and variable amounts of other nutrients like phosphorus and potassium are produced and processed to gain adequate and competitive recycling fertilizers as well as (functional) fillers in (bio-)polymer compounds. In cooperation with the Brazilian partners concepts for a sustainable reuse of ashes will be identified.
At this, different possibilities for an optimum combustion of the bagasse are investigated at Fraunhofer UMSICHT and the Karlsruhe Institute of Technology. After preliminary tests in a laboratory reactor at KIT, pilot tests on a larger scale are carried out in different furnaces in the combustion technology center at Fraunhofer UMSICHT. The aim is to optimize the thermal decomposition to produce nutrient-rich ashes. Particularly the nutrients phosphorus and potassium are in the focus of scientists. This main nutirents should remain in the ashes in the highest possible concentration. After the incineration steps the produced ash is pelletized or granulated to fertilizer, in order to enable a simple application to agricultural land in Brazil. Different handling tests will be performed at Fraunhofer UMSICHT in Oberhausen to get information about the ideal handling of the produced types of fertilizer. Findings on the fertilizing effect of various bagasse ashes on plant growth should provide targeted and integrated recommendations for the treatment and burning of bagasse to improve the nutrient availability.