Cashing cashew - biobased building blocks from cashew nut shells

The Cashing Cashew project focuses on isolation and purification of Cashew Nut Shell Liquid (CNSL) from Cashew Nut Shells (CNS) in order to fully utilize this valuable by-product of the cashew nut production.
Global cashew nut production is about 4 million mt/ tons/yr. Of the cashew nut, about 70 % is shell that is removed in processing and currently typically burned as a dirty and inefficient fuel or discarded as waste. This is not only creating an environmental issue but also wasting valuable by-products. The shell contains circa 20-30 % brown viscous liquid, Cashew Nut Shell Liquid (CNSL). This natural resin contains valuable chemical components, for example, cardanol, cardol, and anacardic acid. CNSL and its derivatives have several industrial uses as for example biobased additives, polymeric building blocks, and biodiesel.
Part of the CNSL can be extracted during the roasting process prior to separating the shell and nut kernel. The shell waste still has a high CNSL concentration that can be isolated by solvents or pressing (expeller). Expeller process is simple and not capital-intensive; therefore it is commonly used. The main disadvantages of the method are the high energy consumption and that 3-5 % oil remains in the press-cake producing harmful gases in burning. Also, the resulting cake is too dense to be further processed to charcoal or other useful application. The objective of this project is to study the purification of the CNSL obtained from pyrolytic isolation to find the most efficient way of making use of the CNSL oil and the total Cashew Nut Shell biomass. An initial evaluation of potential applications is also performed.