Experimental Bench-Scale Study of Residual Biomass Syngas Desulfurization Using ZnO-Based Adsorbents

Abstract

Dry-bed adsorptive desulfurization of biomass-based syngas with a low- to medium sulfur content using ZnO was studied as an alternative to conventional wet-scrubbing processes for a small- to medium-scale biomass-to-liquid process concept. Following laboratory-scale long-term H2S breakthrough experiments in a previous study, desulfurization tests were scaled-up to bench-scale with actual bio-syngas to verify the lab-scale results under more realistic process conditions. A desulfurization unit was constructed and connected to a steam-blown atmospheric pilot-scale fluidized bed gasifier. Two successful 70+ h test campaigns were conducted with H2S removal below the breakthrough limit using full-sized ZnO adsorbent particles. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy elemental analysis, and Brunauer–Emmett–Teller (BET) surface area characterization of the fresh and spent adsorbent pellets were performed. SEM micrographs displayed the outward enlarging particle size in the sulfided layer. Characterization showed significant core–shell sulfidation behavior with a few hundred micron-thick sulfided layer leaving the majority of ZnO unutilized. Adsorbents lost most of their porosity in use, which was evident from BET surface area results. Simultaneous COS removal was found possible by the hydrolysis reaction to H2S. Furthermore, evidence of minor chlorine adsorption was found, thus highlighting the need for a dedicated HCl removal step upstream of desulfurization.

Advanced Biofuels Based on Fischer–Tropsch Synthesis for Applications in Gasoline Engines

“…This measurement provides a full-scale analysis of the fuel properties so that an informed decision can be made as to the circumstances under which the blended fuel can be used. Fischer–Tropsch fuel was produced in a state-of-the-art atmospheric/vacuum distillation column in UniCRE laboratories within the COMSYN project [ 4 ].…”

“…The FT-naphtha distillation fraction by mass (BP 30–180 °C) was produced in an atmospheric/vacuum distillation column in UniCRE laboratories from FT products created within the COMSYN project [ 4 ].…”

“…The directive supports the development of renewable energy sources over the next decade with a binding EU-wide target of at least 32% for renewable energy by 2030, to be achieved jointly by the Member States. To this end, the Directive contains a number of sectoral measures to promote the further use of energy from renewable sources in the electricity, heating, cooling and transport sectors, with the general aim of contributing to reducing greenhouse gas emissions, improving energy security, and strengthening Europe’s leadership in technologies and industry in terms of renewable energy and job creation and growth [ 3 , 4 ].…”

Activated Carbons for Syngas Desulfurization: Evaluating Approaches for Enhancing Low-Temperature H2S Oxidation Rate

“…The gasification facility consisted of a bubbling fluidized bed (BFB), a hot filtration unit, and a reformer unit (Ni-based catalyst) [20]. The modified bench-scale unit [21], shown in Figure 1, was connected to the reformer slipstream.…”

“…The gasification facility consisted of a bubbling fluidized bed (BFB), a hot filtration unit, and a reformer unit (Ni-based catalyst) [20]. The modified bench-scale unit [21], shown in Figure 1, was connected to the reformer slipstream. The bench-scale system consisted of the following units: (1) water scrubbing column with optional formic acid and fresh water feeding, (2) jacketed water cooling tube for gas temperature control, (3) metallic packed-bed reactor with flow distributor before the bed, (4) Masterflex peristaltic pump, and (5) flow meter (pressure-difference method).…”