Experimental evaluation of biomass gasifier integrated solar hybrid dryer using shrimps: Gasifier performance, modelling of drying behaviour and quality analysis

Abstract

The study was carried out to evaluate the performance of a biomass gasifier as a backup heating source to a solar dryer and to analyze the drying characteristics and the quality attributes of shrimps (Metapenaeus dobsoni) drying in the solar-gasifier hybrid dryer. The coconut shell was used as a biomass feedstock for the operation of a downdraft gasifier to generate producer gas. The shrimp samples were dried in a solar-gasifier hybrid dryer to the final moisture contents of 18% (d.b.), 16% (d.b.), and 17% (d.b.) within 6 h, 9 h, and 6 h under hybrid, solar, and gasifier modes, respectively. The thermal efficiency of the downdraft gasifier was estimated to be 73% and 67.5% for the coconut shell feedstock during hybrid and gasifier modes of operation. Modeling of drying data revealed that page model was the best fit for solar and hybrid modes of operation, whereas Midili model accurately predicted the drying behavior of shrimp in the gasifier mode. Proximate composition of shrimps was not affected by different drying modes. Total volatile basic nitrogen (TVB-N), trimethylamine (TMA), and thiobarbituric acid reactive substance (TBARS) values of shrimps were found to be within the safe limit. The rehydration ratio of dried shrimps for hybrid, solar, and gasifier modes was 2.39, 2.52, and 2.49, respectively. The shrinkage (%) observed under the hybrid, solar, and gasifier modes was 20.71%, 19.95%, and 25.45%, respectively. The drying modes positively affected the color development in shrimps.