Advanced dual fluidized bed steam gasification of wood and lignite with calcite as bed material

Gasification of biomass is an attractive technology for combined heat and power (CHP) production. A dual fluidized bed steam gasifier is in commercial operation at the biomass CHP plant in Guessing/Austria since 2002. For circulating fluidized bed applications the bed material consumption is economically crucial. Thus, cyclones for circulating fluidized beds need to be designed properly. Some erosion and caking in the cyclone of the gasifier could be observed with increasing hours of operation. The influences of these effects as well as the influence of the solid circulation rate between the two units on the separation efficiency were investigated by fluid-dynamic investigations using a scaled cold model. The results show that due to erosion and caking elutriation rates are increased, especially for smaller particles. However, the cyclone achieves fractional separation efficiencies of more than 99.9%.

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In-Situ CO2-Absorption in a Dual Fluidized Bed Biomass Steam Gasifier to Produce a Hydrogen Rich Syngas

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1395 ◽

2007 ◽

Vol 5 (1) ◽

Cited By ~ 41

Author(s):

Christoph Pfeifer ◽

Bernhard Puchner ◽

Hermann Hofbauer

Keyword(s):

Fluidized Bed ◽

Renewable Energy Sources ◽

Steam Gasification ◽

Co2 Absorption ◽

Producer Gas ◽

High Hydrogen ◽

Selective Transport ◽

Operation Conditions ◽

Dual Fluidized Bed ◽

Bed Material

Within the last years renewable energy sources came more and more into the public focus. Steam gasification of solid biomass yields high quality producer gases that can be used for efficient combined heat and power production (CHP) and as a renewable resource for chemical syntheses. The dual fluidized bed steam gasification technology provides the necessary heat for steam gasification by circulating hot bed material that is heated in a second fluidized bed reactor by combustion of residual biomass char. The hydrogen content in producer gas of such gasifiers is about 40vol% (dry basis). Addition of carbonates to the bed material and adequate adjustment of operation conditions in the reactors allow selective transport of CO2 from gasification to combustion zone (Absorption Enhanced Reforming AER concept). An 8MW (fuel power) CHP plant successfully demonstrates gasification in Guessing, Austria since 2002. A process development unit (100 kW fuel power) has been recently operated to investigate the potential of the selective CO2 transport achieving a H2 content of up to 75vol% (dry basis) in the producer gas. No significant increase in tar formation occurs despite the low gasification temperatures (600-700°C). It can be shown, that the selective transport of CO2 yields high hydrogen contents in the producer gas and the possibility of operating at lower temperatures increases the efficiency of energy conversion.

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The mechanism of bed material coating in dual fluidized bed biomass steam gasification plants and its impact on plant optimization

Powder Technology ◽

10.1016/j.powtec.2013.04.022 ◽

2013 ◽

Vol 245 ◽

pp. 94-104 ◽

Cited By ~ 44

Author(s):

Friedrich Kirnbauer ◽

Hermann Hofbauer

Keyword(s):

Fluidized Bed ◽

Steam Gasification ◽

Plant Optimization ◽

Dual Fluidized Bed ◽

Bed Material

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Investigations on Bed Material Changes in a Dual Fluidized Bed Steam Gasification Plant in Güssing, Austria

Energy & Fuels ◽

10.1021/ef200746c ◽

2011 ◽

Vol 25 (8) ◽

pp. 3793-3798 ◽

Cited By ~ 80

Author(s):

Friedrich Kirnbauer ◽

Hermann Hofbauer

Keyword(s):

Fluidized Bed ◽

Steam Gasification ◽

Dual Fluidized Bed ◽

Gasification Plant ◽

Bed Material

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Influence of different bed material mixtures on dual fluidized bed steam gasification

Energy ◽

10.1016/j.energy.2018.05.158 ◽

2018 ◽

Vol 157 ◽

pp. 957-968 ◽

Cited By ~ 28

Author(s):

A.M. Mauerhofer ◽

F. Benedikt ◽

J.C. Schmid ◽

J. Fuchs ◽

S. Müller ◽

...

Keyword(s):

Fluidized Bed ◽

Steam Gasification ◽

Dual Fluidized Bed ◽

Bed Material

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Parametric Study on the Adjustability of the Syngas Composition by Sorption-Enhanced Gasification in a Dual-Fluidized Bed Pilot Plant

Energies ◽

10.3390/en14020399 ◽

2021 ◽

Vol 14 (2) ◽

pp. 399

Author(s):

Selina Hafner ◽

Max Schmid ◽

Günter Scheffknecht

Keyword(s):

Fluidized Bed ◽

Ghg Emissions ◽

Space Velocity ◽

Synthesis Process ◽

Wood Pellets ◽

High Hydrogen ◽

Syngas Production ◽

Dual Fluidized Bed ◽

Bed Material ◽

Gasification Temperature

Finding a way for mitigating climate change is one of the main challenges of our generation. Sorption-enhanced gasification (SEG) is a process by which syngas as an important intermediate for the synthesis of e.g., dimethyl ether (DME), bio-synthetic natural gas (SNG) and Fischer–Tropsch (FT) products or hydrogen can be produced by using biomass as feedstock. It can, therefore, contribute to a replacement for fossil fuels to reduce greenhouse gas (GHG) emissions. SEG is an indirect gasification process that is operated in a dual-fluidized bed (DFB) reactor. By the use of a CO2-active sorbent as bed material, CO2 that is produced during gasification is directly captured. The resulting enhancement of the water–gas shift reaction enables the production of a syngas with high hydrogen content and adjustable H2/CO/CO2-ratio. Tests were conducted in a 200 kW DFB pilot-scale facility under industrially relevant conditions to analyze the influence of gasification temperature, steam to carbon (S/C) ratio and weight hourly space velocity (WHSV) on the syngas production, using wood pellets as feedstock and limestone as bed material. Results revealed a strong dependency of the syngas composition on the gasification temperature in terms of permanent gases, light hydrocarbons and tars. Also, S/C ratio and WHSV are parameters that can contribute to adjusting the syngas properties in such a way that it is optimized for a specific downstream synthesis process.

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