Analysis on the coupling of biomass gasification processes with a parabolic trough concentrating solar plant

The energy needed from gasification processes to convert a solid fuel, the biomass, into a gaseous one is usually supplied by the partial oxidation of the fuel in the gasification reactor. However, the use of solar power as an external thermal input is attractive to improve the energy content and the quality of the product gas. Solar parabolic trough (PT) technology, using molten salt both as heat transfer fluid and thermal storage medium can provide an energy input to a gasification reactor in a stable and continuous way throughout the whole process. The gas produced by a reactor supplied by solar energy has a better quality in terms of Low Heat Value, “cold gas efficiency”, “carbon efficiency” and tar content. Molten salt, acting as thermal fluid in the heat exchanger within the reactor (in the place of hot gas) increases reliability and avoids unsafe service interruptions for the facility. At the same time, the abovementioned Concentrating Solar Plant (CSP) plant can benefit from the syngas. In particular this latter may be profitable for covering the CSP nocturnal losses, decreasing the use of fossil fuel, allowing power production in cogeneration to be used as heat for salts heating up, in order to have a power generation extension. To sum up, this paper investigates the benefits ensured by this coupling to both plant technologies and explains the method to be used in case of agro-industrial residuals used as feed