Assessment of the pyrolysis products from halophyte Salicornia bigelovii cultivated in a desert environment

The development of bioenergy in marginal environments has been hampered by the lack of sustainable sources of biomass. The halophyte Salicornia bigelovii, has been found to adapt extremely well in a desert climate. In this study, the S. bigelovii seed and the seedless-plant have been assessed, for the first time, for biofuel and biochar production through thermochemical conversion (pyrolysis) in an auger reactor operated at 550 °C. Both feedstocks showed significant differences in chemical composition, with the seed being closer to the characteristics of seeds from common oilseed crops. The S. bigelovii seed produced high bio-oil yield (79.9% of total liquid) of high pH predominated with fatty acids commonly found in vegetable oils. The S. bigelovii seedless-plant produced a liquid of significantly low bio-oil (10% of total liquid) with an aqueous phase of pH and salinity close that of brackish water. The biochars were of moderate heating value and limited potentials for soil amendment due to the high ash content in the biomass, but are reasonably stable for long term carbon sequestration due to their low O/C and H/C ratios (<0.1 and <1.0, respectively). Comparative assessment in terms of the conversion efficiency and renewability indicated that pyrolysis of the S. bigelovii seed offers a good opportunity for biofuel production in arid/semi-arid saline regions against the alternative option of transesterification conversion.