Solar Gasification of Biomass: A Molten Salt Pyrolysis Study

Abstract

A novel solar process and reactor for thermochemical conversion of biomass to synthesis gas is described. The concept is based on dispersion of biomass particles in a molten inorganic salt medium and, simultaneously, absorbing, storing and transferring solar energy needed to perform pyrolysis reactions in the high-temperature liquid phase. A lab-scale reactor filled with carbonates of potassium and sodium was set up to study the kinetics of fast pyrolysis and the characteristics of transient heat transfer for cellulose particles (few millimeters size) introduced into the molten salt medium. The operating conditions were reaction temperatures of 1073–1188 K and a particle peak-heating rate of 100 K/sec. The assessments performed for a commercial-scale solar reactor demonstrate that pyrolysis of biomass particles dispersed in a molten salt phase could be a feasible option for the continuous, round-the-clock production of syngas, using solar energy only.

Combined molten salt–Ni/Al2O3 as synergistic medium for high-quality syngas production

“…In fact, the effective use of high-temperature solar heat for driving endothermic biomass pyrolysis process provides considerable advantages over conventional processes [1]. The partial combustion of biomass with added O 2 or air, as required in conventional processes, is eliminated, so all the biomass can be converted to http useful syngas [1,2]. In addition, the product gas is neither diluted by extra N 2 from feed air nor contaminated with other combustion by-products.…”

“…However, the application of sole solar energy without supplementary conventional sources (e.g. fossil fuels, or the partial combustion of feedstock) to a continuous biomass pyrolysis process requires the development of a solar-receiver reactor capable of continuous operation [2]. Solar thermal conversion of biomass can be achieved by direct irradiation of concentrated solar energy.…”

Synthesis of Transportation Fuels from Biomass: Chemistry, Catalysts, and Engineering

“…Solar energy is also used to dry wet biomass prior to the gasification process. Figure 7 shows the concept of a solar gasification reactor based on a design by Adinberg et al 84 The reactor is a central spherically or cylindrically shaped reactor. An array of vertical tubes are evenly distributed around the reactor.…”

“…[79][80][81][82][83][84] Solar gasification decreases the amount of biomass that needs to be burned in the gasification process, thus improving the PTE. Heat is provided to the gasification unit using concentrated solar gasifiers and specially designed solar reactors.…”

Analysis of Hybrid Hydrogen Systems: Final Report

“…One interesting option is the use of concentrated solar energy to heat molten salts, which then can be used as a pyrolyzing medium. Preliminary research suggests that, using this approach, a pyrolysis reactor could be run at steady state on solar energy alone (Adinberg, Epstein, and Karni 2004).…”