The efficiency of selecting the optimal feedstock, increasing the process severity, improving the catalysts activity, and using alternative catalytic routes are compared, taking into account the specific issues related to deep hydrodesulfurization/hydrodenitrogenation/ hydrodeoxygenation, i.e., chemical aspects, kinetics and catalysts.
The proposed thermoplastic extrusion pretreatment favored cellulose decrystallization and increased the surface area and porosity of the feedstock increasing the amount of soluble fiber [ 6, 8].
The depletion in fossil feedstocks, increasing oil prices, and the ecological problems associated with CO2 emissions are forcing the development of alternative resources for energy, transport fuels, and chemicals: the replacement of fossil resources with CO2 neutral biomass.
Nonetheless, land use and related challenges need to be considered as the demand for AD feedstocks increases with the fast growth of the sector.
The net loss of dry mass which concentrates the phosphorus in the final feedstocks of vermicomposting also increases the phosphorus content (Ravindran and Sekaran 2010).
The solar process saves biomass resource because partial combustion of the feedstock is avoided, it increases the energy conversion efficiency because the calorific value of the feedstock is upgraded by the solar power input, and it also reduces the need for downstream gas cleaning and separation because the gas products are not contaminated by combustion by-products.
Production of exotic species for feedstock may increase the risk of escape from agriculture and invasion into natural ecosystems.
Adding Al2O3 to the feedstock powder increased the overall deposition efficiency, though the Al2O3 itself deposited less efficiently than the stainless steel.
The mechanical pretreatment was carried out with the purpose of enhancing the biodegradability of the macroalgal feedstock by increasing the specific surface area available during the anaerobic co-digestion.
For example, the use of lignocellulosic sugar can help a corn or grain-based ethanol plant by supplementing its feedstock to increase the value of the ethanol by making use of the Renewable Fuel Standard incentives or to maintain feedstock options in the face of variations in corn prices.
