Techno-economic analysis and life cycle assessment of olive and wine industry co-products valorisation

In this work, a valorisation of olive and wine industry co-products (olive pomace and grape marc, respectively) through different thermochemical processes is studied. The characterization of olive pomace and grape marc is made to evaluate which thermochemical process is more suitable for each type of biomass and a specific application. Then, a life cycle assessment (LCA) of olive pomace value chain is made to assess the environmental impacts. Several scenarios of biomass conversion process were considered: combustion, gasification and hydrothermal carbonization (HTC) followed by gasification to generate electricity; and pyrolysis to produce biochar, bio-oil and syngas. Finally, a techno-economic analysis was performed for each mentioned scenario to evaluate the feasibility and conclude which scenario is more economically advantageous. Results suggest that valorisation of olive pomace might be more suitable through the gasification process and grape marc through the pyrolysis process. From the LCA was possible to conclude that combustion scenario has the highest environmental impact. In comparison, gasification, HTC and pyrolysis presented a lower impact with a value of 69.45%, 50.96% and 40.97%, respectively, considering combustion as 100% impact. Regarding the techno-economic analysis, several scenarios have promising results with some scenarios with payback periods inferior to 5 years. The only exception is HTC followed by gasification which in current days is not competitive with other technologies. Overall gasification and pyrolysis are promising alternatives to the valorisation of olive pomace and grape marc. The drying process has an important role in terms of environmental impact and economic viability.