Reinhard Rauch

The FICFB — Gasification Process

A novel fluidized bed gasification reactor has been developed to get a product gas with a high calorific value (up to 15 MJ/Nm3) and nearly free of nitrogen. The gasification process is based on an internally circulating fluidized system and consists of a gasification zone fluidized with steam and a combustion zone fluidized with air. The circulating bed material acts as heat carrier from the combustion to the gasification zone. Gas mixing between these two zones is avoided by construction measures. Furtheron, the apparatus is characterized by a very compact design.

Fluidized Bed Steam Gasification of Solid Biomass - Performance Characteristics of an 8 MWth Combined Heat and Power Plant

The work focuses on a dual fluidized bed gasification technology that is successfully operated for combined heat and power production at a scale of 8 MWth in Guessing/Austria since 2002. The reactor concept consists of a circulating fluidized bed system with a steam-fluidized bubbling bed integrated into the solids return loop. Accompanying the operation of the commercial scale plant, parameter models have been developed and validated by comparison to measured data. As the models naturally fulfill mass and energy balances, the simulation also allows the validation of measurement data. The behaviour of the plant is studied by carrying out variations of selected parameters. Evaluation of different plant operation cases yields correlations between process variables. The solids circulation rate is shown versus riser exit velocity. Fuel water content and gasification temperature significantly influence global plant performance. Simulation predicts the efficiency of the existing power plant in optimized operation. Finally, part load behaviour is investigated and performance maps of the CHP plant are presented. High fuel water content at high gas engine load results in high gas velocities in the riser (erosion limit) and higher heat ratio in the produced energy. It is concluded that CHP-concepts based on fluidized bed steam gasification can reach high electric efficiencies and high overall fuel utilization rates even at small plant capacities of about 10 MWth.

COUPLING OF BIOMASS STEAM GASIFICATION AND AN SOFC - GAS TURBINE HYBRID SYSTEM FOR HIGHLY EFFICIENT ELECTRICITY GENERATION

An energetic model of an internal reforming solid oxide fuel cell (IRSOFC) is developed. It is integrated in a process coupling fluidized bed steam gasification of biomass and an IRSOFC-gas turbine hybrid cycle. Process simulation is performed using the software package IPSEpro. The model of the gasification and gas conditioning section is based on data from the 8 MW (fuel power) plant in Guessing/Austria, while the fuel cell is modeled based on recent literature data. Heat utilization for power generation is considered covering both hybrid cycle exhaust and heat from the gasification process. Electric efficiencies up to 43% are expected for combined heat and power application even at small plant capacities in the range of 8 MW fuel power.Copyright

Fluidized Bed Steam Gasification of Solid Biomass: Analysis and Optimization of Plant Operation Using Process Simulation

Fluidized bed steam gasification of solid biomass yields a high quality producer gas, which can be used for efficient combined heat and power production (CHP) and as an intermediate product for chemical syntheses. In order to study the behavior of an 8 MW (fuel power) CHP plant, which has been in successful operation since 2001, a comprehensive model library has been developed for the equation-oriented process simulation software IPSEpro. The models are validated with measured data from the commercial scale plant. Because every model is based on the conservation of mass and energy, the simulation also allows the validation of measured data. By solution of a system describing the entire process, which uses measured data as input, a reference case for actual plant operation can be defined. In a next step, the behavior of the plant is studied during variations of selected parameters. Therefore, a model of the gasification reactor, which is able to describe the behavior during parameter variation, is necessary. It can be shown that fuel water content and gasification temperature significantly influence the global plant performance. The simulation predicts the efficiency of the existing power plant in optimized operation. Finally, part load behavior is investigated and a performance map of the CHP plant is presented. The results show that CHP-concepts based on fluidized bed steam gasification can reach high electric efficiencies and high overall fuel utilization rates even at small plant capacities of 10 MW fuel power.Copyright

Fischer-Tropsch Synthesis to Biofuels (BtL Process)

Fischer-Tropsch (FT) synthesis is one option to produce liquid transportation fuels from carbon-containing feedstocks. In the past, FT synthesis was used mainly to convert coal or natural gas to diesel and gasoline. In the last decade, much RD the types of FT reactors; and also the reaction conditions including kinetic laws and mechanistic proposals.

Hydrogen production from biomass: The behavior of impurities over a CO shift unit and a biodiesel scrubber used as a gas treatment stage

Most of the hydrogen produced is derived from fossil fuels. Bioenergy2020+ and TU Wien have been working on hydrogen production from biomass since 2009. A pilot plant for hydrogen production from lignocellulosic feedstock was installed onsite using a fluidized bed biomass gasifier in Güssing, Austria. In this work, the behavior of impurities over the gas conditioning stage was investigated. Stable CO conversion and hydration of sulfur components could be observed. Ammonia, benzene, toluene, xylene (BTX) and sulfur reduction could be measured after the biodiesel scrubber. The results show the possibility of using a commercial Fe/Cr-based CO shift catalyst in impurity-rich gas applications. In addition to hydrogen production, the gas treatment setup seems to also be a promising method for adjusting the H2 to CO ratio for synthesis gas applications.

Biokerosene Production from Bio-Chemical and Thermo-Chemical Biomass Conversion and Subsequent Fischer-Tropsch Synthesis

Synthetic fuels derived from synthesis gas provided from gasification of solid fuels using the Fischer-Tropsch Synthesis are well-known and used since the 1920’s. The initial process used coal as feedstock to produce mainly diesel like fuels when crude oil was not at hand. Nowadays and especially in the context of alternative and climate friendly fuels new process chains are taken into consideration based on this overall principle. This includes the production of “green” syngas by biomass gasification or reforming of bio-methane from e.g. biogas plants based on a biochemical biomass conversion. Against this background the overall goal of this paper is to give an overview of the current state of these two syngas provision pathways and the subsequent synthesis options, mainly focusing on the Fischer-Tropsch Synthesis. The overall process chains can be categorized into the Biomass-to-Liquids (BtL) and the Biogas-to-Liquids (Bio-GtL) pathways.

Possibility of industrial scale BioH 2 production from product gas in existing dual fluidized bed biomass gasification plant

Conceptual solution of production of pure renewable hydrogen from wood gas or product derived from the commercial biomass steam gasification plant Güssing, Austria was carried out. The proposed process of product gas upgrading consisted of tree basic operations: (I) catalyzed water-gas shift (WGS) reaction, (II) gas drying and cleaning in a wet scrubber and (III) hydrogen purification by pressure swing adsorption. The tail gas or adsorbate can be used like fuel for gas engine for electrical energy production or like a boiler fuel for hot water-heat production.

Characterization of Biomass Used for Fischer-Tropsch Diesel Synthesis

The characteristics of biomass used at Combined Heat and Power (CHP) plant Gussing (Austria) were determined over three samples taken from the wood chips, including proximate analysis: moisture, ash, cellulose and lignin content, and ultimate analysis: total organic carbon, concentration of H, S, N, and O, high and low heating value and FT-IR. Based on the characteristics of biomass, investigation of the syngas composition has been performed. The results showed that most of the proximate and ultimate analysis, as well as FT-IR analysis of wood chips were comparable with the standards and with other results found in literature. Extrinsic moisture higher than the standard value was obtained due to high humidity in the atmosphere during harvesting, causing difficulties of the feeding inside the fluidized bed gasifier and affecting the quality of the syngas. Low concentrations of S and N determined low emissions of NH3 and H2S, providing a synthesis gas suitable for Fischer-Tropsch synthesis.

Mathematical Modeling and Experimental Study of Hydrogen Production by Catalytic Steam Reforming of Methane

Steam reforming of methane in a packed bed reactor filled with Nickel based catalyst supported on Alumina, (Al2O3) is theoretically and experimentally studied and analyzed. State of the art Finite Element Method software, COMSOL Multiphysics is used to simulate a steady state two dimensional heterogeneous model, coupled with detailed reaction mechanisms modeling surface and gas-phase kinetics that takes into account the diffusion reaction phenomena inside the particles. The simulation results are compared favorably with experimental data. It is shown that strong axial and radial temperature gradients exist near the reactor wall The obtained results are important in design and optimizing of commercial reactors.Copyright