Kentaro Umeki

Kinetic Study of Catalytic Steam Gasification of Biomass by Using Reactive Flash Volatilisation

Reactive flash volatilisation is an autothermal process to convert biomass into tar‐free synthesis gas under steam‐rich conditions. This article studies the kinetics of reactive flash volatilisation by using Ni, PtNi, RuNi, ReNi, and RhNi catalysts supported on alumina. The rates of mass loss of cellulose, xylan, and lignin were measured and compared with those of the synthetic biomass mixture and pinewood sawdust. The kinetic parameters were calculated with and without catalysts by using a wire‐mesh isothermal thermogravimetric analyser in an equimolar steam/N2 atmosphere and high heating rates of 8.6×102, 1.1×103, and 1.3×104 °C min−1 at 700, 750, and 800 °C, respectively. The results revealed three distinct regimes of the rate of mass loss: pyrolytic decomposition, reforming, and char gasification. The catalysts increased the rate of mass loss in the reforming regime. RhNi and RuNi supported catalysts showed higher reforming rates than other catalysts. This study provides direct evidence of the in situ catalytic removal of tar during gasification of biomass.

Catalytic hydrothermal liquefaction of biomass with K2CO3 for production of gasification feedstock

ABSTRACT The introduction of alkali catalyst during hydrothermal liquefaction (HTL) improves conversion and allows the aqueous liquid product to be used as gasification feedstock. This study investigates the effect of reaction temperature (240–300°C), sawdust mass fraction (9.1–25%) and reaction time (0–60 min) during K2CO3-catalytic HTL of pine sawdust. The highest biomass conversion (75.2% carbon conversion and 83.0% mass conversion) was achieved at a reaction temperature of 270°C, 9.1% sawdust mass fraction and 30 min reaction time; meanwhile, the maximum aqueous product (AP) yield (69.0% carbon yield and 73.5% mass yield) was found at a reaction temperature of 300°C, 9.1% sawdust mass fraction and 60 min reaction time. Based on the main experimental results, models for carbon and mass yields of the products were developed according to face-centered central composite design using response surface methodology. Biomass conversion and product yields had a positive correlation with reaction temperature and reaction time, while they had an inverse correlation with sawdust mass fraction. Further investigation of the effects of biomass/water and biomass/K2CO3 ratios revealed that both high water loading and high K2CO3 loading enhanced conversion and AP yield.

Biomass gasification fundamentals to support the development of BTL in forest industry

The Nordic forest industry creates new concepts and provides solutions to mitigate climate challenge. One of the most interesting concepts is the integrated production of pulp and paper products and transportation fuels. The Finnish and Swedish activities are aiming to the same objective increased profitability of pulp and paper industry by using their by-products for producing high-quality renewable fuels. The technical approaches are different. For the technologies the scientific co-operation in the R & D consortium of VTT-ETC-LTU-SINTEF created background know-how through experiments and modelling in NORDSYNGAS project realised between 2010–2014. The objective of the project was to create new scientific knowledge on fluidised-bed and entrained-flow gasification of biomass residues and black liquor in order to support the Nordic industrial development and demonstration projects. In addition, close co-operation between the Finnish, Swedish and Norwegian R&D organisations was organised. ISBN, ISSN ISBN 978-951-38-8220-4 (URL: http://www.vtt.fi/publications/index.jsp) ISSN-L 2242-1211 ISSN 2242-122X (Online)