In Situ Sub- and Supercritical Water Gasification of Nano-Nickel (Ni2+) Impregnated Biomass for H2 Production

With the rapid consumption of fossil fuels, along with the ever-increasing environmental pollution, it is becoming a top priority to explore efficient photocatalysts for the production of renewable hydrogen and degradation of pollutants. Here, we fabricated a composite of g-C3N4/TiO2 via an in situ growth method under the conditions of high-temperature calcination. In this method, TiO2 nanowires with a large specific surface area could provide enough space for loading more g-C3N4 nanoparticles to obtain C3N4/TiO2 composites. Of note, the g-C3N4/TiO2 composite could effectively photocatalyze both the degradation of several pollutants and production of hydrogen, both of which are essential for environmental governance. Combining multiple characterizations and experiments, we found that the heterojunction constructed by the TiO2 and g-C3N4 could increase the photocatalytic ability of materials by prompting the separation of photogenerated carriers. Furthermore, the photocatalytic mechanism of the g-C3N4/TiO2 composite was also clarified in detail.

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Supercritical water gasification (SCWG) as a potential tool for the valorization of phycoremediation-derived waste algal biomass for biofuel generation

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2021.126278 ◽

2021 ◽

pp. 126278

Author(s):

Yoong Kit Leong ◽

Wei-Hsin Chen ◽

Duu-Jong Lee ◽

Jo-Shu Chang

Keyword(s):

Supercritical Water ◽

Algal Biomass ◽

Supercritical Water Gasification ◽

Potential Tool

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Gasification of Biomass in Supercritical Water, Challenges for the Process Design—Lessons Learned from the Operation Experience of the First Dedicated Pilot Plant

Processes ◽

10.3390/pr9030455 ◽

2021 ◽

Vol 9 (3) ◽

pp. 455

Author(s):

Nikolaos Boukis ◽

I. Katharina Stoll

Keyword(s):

Organic Matter ◽

Supercritical Water ◽

Process Design ◽

Pilot Plant ◽

Lessons Learned ◽

Present Contribution ◽

Flow Process ◽

Combustible Gas ◽

Supercritical Water Gasification ◽

Robust Process

Gasification of organic matter under the conditions of supercritical water (T > 374 °C, p > 221 bar) is an allothermal, continuous flow process suitable to convert materials with high moisture content (<20 wt.% dry matter) into a combustible gas. The gasification of organic matter with water as a solvent offers several benefits, particularly the omission of an energy-intensive drying process. The reactions are fast, and mean residence times inside the reactor are consequently low (less than 5 min). However, there are still various challenges to be met. The combination of high temperature and pressure and the low concentration of organic matter require a robust process design. Additionally, the low value of the feed and the product predestinate the process for decentralized applications, which is a challenge for the economics of an application. The present contribution summarizes the experience gained during more than 10 years of operation of the first dedicated pilot plant for supercritical water gasification of biomass. The emphasis lies on highlighting the challenges in process design. In addition to some fundamental results gained from comparable laboratory plants, selected experimental results of the pilot plant “VERENA” (acronym for the German expression “experimental facility for the energetic exploitation of agricultural matter”) are presented.

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