A high temperature drop-tube and packed-bed solar reactor for continuous biomass gasification

Abstract

Development and experimental study for hydrogen production from the thermochemical two-step water splitting cycles with a CeO 2 coated new foam device design using solar furnace system AIP Conference Proceedings 1850, 100003 (2017) Abstract. Biomass gasification is an attractive process to produce high-value syngas. Utilization of concentrated solar energy as the heat source for driving reactions increases the energy conversion efficiency, saves biomass resource, and eliminates the needs for gas cleaning and separation. A high-temperature tubular solar reactor combining drop tube and packed bed concepts was used for continuous solar-driven gasification of biomass. This 1 kW reactor was experimentally tested with biomass feeding under real solar irradiation conditions at the focus of a 2 m-diameter parabolic solar concentrator. Experiments were conducted at temperatures ranging from 1000°C to 1400°C using wood composed of a mix of pine and spruce (bark included) as biomass feedstock. The aim of this study was to demonstrate the feasibility of syngas production in this reactor concept and to prove the reliability of continuous biomass gasification processing using solar energy. The study first consisted of a parametric study of the gasification conditions to obtain an optimal gas yield. The influence of temperature and oxidizing agent (H 2 O or CO 2 ) on the product gas composition was investigated. The study then focused on solar gasification during continuous biomass particle injection for demonstrating the feasibility of a continuous process. Regarding the energy conversion efficiency of the lab scale reactor, energy upgrade factor of 1.21 and solar-to-fuel thermochemical efficiency up to 28% were achieved using wood heated up to 1400°C.

Solar Hydrogen Production by Thermochemical Reaction: Development of a Packed-Bed Reactor

“…Packed beds are used in a large industrial thermal-fluid systems applications, such as nuclear reactors [40,41], catalysts [42], and in cryogenics [43,44]. A number of exploratory studies investigated solar thermochemical reaction in packed bed reactor [45][46][47][48]. In Figure 4 a 5 kW solar reactor, subjected to solar radiation up to 2953 suns and operated at temperatures up to 1490 K was demonstrated at PSI [49].…”

Solar-hybrid Thermochemical Gasification of Wood Particles and Solid Recovered Fuel in a Continuously-Fed Prototype Reactor

“…Cavity-type solar gasifiers were extensively studied in many laboratories across the globe [13,14]. They can be directly [15][16][17][18][19] or indirectly [20][21][22][23] irradiated. Directly irradiated solar reactors expose the reactants directly to solar irradiation thanks to a transparent glass window.…”

“…It showed promising results with more than 20% of the incoming sunlight effectively stored as fuel calorific value in the product gas. Since then, other reactor designs, including packed beds [20,25], fluidized beds [18,26], spouted beds [15,27], vortex flow [21,28], drop tube [16,29], and molten salt [10,30] reactors were tested to convert a wide variety of feedstocks such as biomass, coal and different kinds of waste with either steam or CO 2 as an oxidizing agent. Recent exploratory work on hybrid solar gasification makes use of O 2 as a means to maintain the process temperature during sun-lacking periods thanks to combined solar heating and in-situ oxy-combustion [31][32][33][34].…”