Evaluation of dual fluidized bed biomass gasification plants generating electricity, valuable gases, and district heat

Im Zuge des Klimagipfels in Paris haben sich die unterzeichnenden Länder dazu verpflichtet ihre CO2 Emissionen zu verringern, um die globale Erwärmung auf 1.5 °C zu beschränken. Um dieses Ziel zu erreichen, ist der vermehrte Einsatz von erneuerbaren Energieträgern erforderlich. Erneuerbare Energieträger spielen bereits heute eine wichtige Rolle in Österreichs Stromsektor. Über 70 % des Elektrizitätsbedarfs werden mittels erneuerbaren Energien erzeugt. Im Gegensatz dazu sind der Transportsektor und die Industrie sehr stark von fossilen Energieträgern abhängig. Biomasse, besonders feste Biomasse wie Hackschnitzel, besitzt noch großes Potential für verschiedene Anwendungen und kann einen Beitrag zur Reduktion der CO2 Emissionen leisten. Um dieses Potential zu nutzen, bietet sich die Zweibett-Wirbelschicht-Dampfvergasung an. Diese bietet hohe Effizienz und Flexibilität hinsichtlich der Produkte. Aus diesem Grund werden in dieser Arbeit verschiedene Prozesse zur Erzeugung von Elektrizität, hochwertigen Gasen (Wasserstoff, synthetisches Erdgas und eine Gasmischung bestehend aus Wasserstoff und Methan) und Fernwärme untersucht. In weiterer Folge wurde die techno-ökonomische Machbarkeit sowie deren wichtigsten Einflussgrößen ermittelt. Ausgangspunkt für die Berechnungen war eine belastbare Datenbasis bestehend aus Daten kommerzieller Vergasungsanlagen, Experimenten, die im Laufe dieser Arbeit entstanden sind, und einer umfangreichen Literaturstudie. Mit diesen Daten wurden Massen - und Energiebilanzen der untersuchten Prozesse berechnet. Um die technische Machbarkeit zu untersuchen, wurde die Wärmeintegration der Prozesse untersucht, bevor die techno-ökonomische Machbarkeit für Anlagen mit Brennstoffwärmeleistungen von 10, 50, und 100 MW evaluiert wurde. Die Ergebnisse zeigen, dass gezielte Fördermaßnahmen notwendig sind, damit die untersuchten Prozesse wirtschaftlich betrieben werden können. Den größten Einfluss auf die Wirtschaftlichkeit hat der energetische Wirkungsgrad vor den jährlichen Betriebsstunden, den Investitionskosten und dem Holzpreis.Global warming led to the Paris agreement which was signed by the majority of all countries in order to reduce the CO2 emission to keep the global temperature increase below 1.5 °C. Therefore, a shift towards renewable energy carriers is necessary. Renewable energy carriers already have a high share in Austria's electricity sector. More than 70 % of the electricity demand is met by renewable sources. However, the industrial sector and the transportation sector highly depend on fossil energy carriers. In contrast, biomass, especially solid biomass like wood chips, has still a high utilization potential for different processes in Austria. In order to use this potential and to reduce the CO2 emissions, dual fluidized bed biomass steam gasification with its high efficiency and product flexibility can be employed. Therefore, different processes for the production of electricity, valuable gases (hydrogen, synthetic natural gas, and a gas mixture composed of hydrogen and methane), and district heat were investigated in this thesis. The techno-economic feasibility of the investigated processes was evaluated as well as its most significant influencing parameters. Therefore, a robust and reliable data basis derived from commercial gasification plant data, experimental work carried out as part of this thesis, and an extensive literature review was used. With this data basis, mass and energy balances of the investigated processes were calculated. Subsequently, pinch analyses were carried out in order to prove the technical feasibility of the process layouts before the techno-economic assessments for fuel capacities of 10, 50, and 100 MW were evaluated. The results show that governmental support and subsidies are necessary for an economically feasible operation of the investigated processes. The most significant influencing parameters of the economic feasibility are the production efficiency, the annual operating hours, the investment costs, and the feedstock price.26

Betrieb einer PEM-Brennstoffzelle und Anwendungen für BioH2

Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in dt. SpracheToday, hydrogen is mostly produced from fossil fuels like methane and coal. In order to decrease the world's carbon dioxide emissions several sustainable ways of hydrogen generation exist. One of them is electrolysis of water. If it is powered by renewable electricity like solar, hydro or eolic energy it can depict an environmentally friendly and carbon dioxide emission poor way to produce hydrogen with a high purity. Another possibility for sustainable hydrogen production is from biomass. Especially, wood gasi fication with further gas processing seems to be a promising technology which could be realized with the current and proven technology (water gas shift, absorption, membrane separation and adsorption). For gasifi cation, the already industrially applied dual fluidized bed technology has shown advantages which still has room for improvement by means of sorption enhanced reforming (SER). Fuel cells are devices which are able to convert hydrogen directly into electricity and heat without the limits of the Carnot cycle. Several fuel cell technologies exist with its own advantages and disadvantages. A proton exchange membrane (PEM) fuel cell, MobixaneTM, was tested in experiments with Alphagaz 1TM H2 hydrogen (pure hydrogen from a gas cylinder), from Air LiquideTM, and BioH2 acquired from wood gas from biomass gasifi cation. The wood gas from the biomass gasifi cation plant was subsequently processed in a water gas shift unit, in a RME gas scrubbing unit and in a pressure swing adsorption unit in order to achieve high purity BioH2. The experimental results showed that the operation with those two different hydrogen sources made no differences regarding the performance of the PEM fuel cell. A flawless fuel cell operation with BioH2 was possible. The experimental approach with detailed information is part of two papers which can be reviewed in Appendix C of this work. Past experiments using a process chain employing a RME scrubbing unit, a membrane separation unit and a pressure swing adsorption unit showed that a more than 100 hours lasting flawless operation of a PEM fuel cell with hydrogen generated from wood gas was possible. Today hydrogen is needed for several applications. Therefore storage of hydrogen is an important aspect, especially in context with Power to Gas concepts. Different possibilities exist like storage in pressure vessels, storage as liquid and in metal hydrids. A future project for hydrogen is the addition to the natural gas grid in order to reduce dependence of energy imports. This could be realized without issues because the Wobbe index of natural gas and hydrogen is quite similar. If the materials for hydrogen applications are chosen properly no signi cant damages or risks are expected. Several car manufacturers see fuel cells fed by hydrogen as possible future for locomotion being an alternative to combustion engines which could also be powered by hydrogen. Another possible hydrogen application is the utilization in households by fuel cells for satisfying heat and electricity demands which would enhance fuel use efficiency. This seems to be especially the case if several fuel cells are interconnected to a Virtual Power Plant" which is assumed to be able to replace large centralized power plants. Furthermore, hydrogen is an substance which is also needed in very high amounts in re neries, metal and chemical industry.8

Development and experimental validation of a water gas shift kinetic model for Fe-/Cr-based catalysts processing product gas from biomass steam gasification

This paper introduces an improved kinetic model for the water gas shift reaction catalyzed by an Fe-/Cr-based catalyst. The improved model is based on a former model which was developed previously in order to consider the composition and the catalyst poisons (H2S) of product gas derived from dual fluidized bed biomass steam gasification. r(φi,T)=117.8 molg Pa1.71 s⋅exp(−126.6 kJmolR⋅T)⋅p1.77CO⋅p0.23H2O⋅p−0.17CO2⋅p−0.12H2(1−KMALKg). Furthermore, this improved model has been validated with experimental data. The data was generated by a WGS reactor which employed a commercial Fe-/Cr-based catalyst and which processed real product gas from the dual fluidized bed biomass steam gasification plant in Oberwart, Austria. Basically, the validation showed good agreement of the measured and the calculated values for the gas composition (absolute errors of the volumetric fractions of up to 1.5 %) and the temperature profile (absolute errors of up to 21 °C) of the WGS reactor. Of all considered gas components, the CO concentration showed the highest error.The results qualify the improved kinetic model for basic design and engineering of a WGS reactor employing a commercial Fe-/Cr-based catalyst which processes product gas from an industrial scale biomass steam gasification plant.Bioenergy2020+GmbH project (BC20005 Polygeneration III)Austria Research Promoting Agency (FFG

Oxiddispersionsgehaertete Chrombasislegierungen fuer Anwendungen in der Energietechnik Abschlussbericht

Aim of this three-year MaTech project was the development of oxide dispersion-strengthened chrome master alloys for high-temperature applications in the field of energy technology. Due to a specific problem task in the house of the project leader Siemens AG KWU the works focused on the use as so-called double-polar plate in a high temperature fuel cell. Among numerous investigated alloy variations alloys composed of Cr-Fe-rare-earthoxid-(partially with Al) show the best property profile. These alloys characterise themselves by a low thermal extension, a high solidity and excellent hot gas corrosion resistance. By means of two production routes in terms of powder metallurgy the production of flat tools was successfully demonstrated. In the case of the production route via hot-rolls the range from pre-series production to the complete component was established. (orig.)Inhalt dieses dreijaehrigen MaTech-Projektes war die Entwicklung oxiddispersionsgehaerteter Chrombasislegierungen fuer Hochtemperatur-Anwendungen in der Energietechnik. Aufgrund einer konkreten Problemstellung im Hause des Projektfuehrers Siemens AG KWU, wurde stellvertretend fuer dieses Anwendungsgebiet der Einsatz als sog. bipolare Platte in der Hochtemperaturbrennstoffzelle in den Mittelpunkt der Arbeiten gestellt. Aus einer Vielzahl untersuchter Legierungsvariationen zeigen Legierungen der Zusammensetzungen Cr-Fe-Seltenerdoxid-(z.T. mit Al) das beste Eigenschaftsprofil. Diese Legierungen zeichnen sich z.B. durch eine geringe Waermedehnung, eine hohe Festigkeit und eine ausgezeichnete Heissgaskorrosionsbestaendigkeit aus. Anhand zweier pulvermetallurgischer Herstellrouten konnte erfolgreich die Fertigung von Flachzeug demonstriert werden, und im Falle der Herstellroute ueber Warmwalzen das Niveau einer Vorserienfertigung bis hin zur fertigen Komponente etabliert werden. (orig.)Available from TIB Hannover: F00B134 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman

Techno-economic assessment of biomass-based natural gas substitutes against the background of the EU 2018 renewable energy directive

This paper investigates biomethane and BioSNG production processes against the background of the 2018 renewable fuel directive of the European Union (EU). The investigated biomethane processes use manure, clover grass, and grass silage as feedstock, are based on membrane separation gas upgrading processes, and generate 1.0 and 4.8 MW of biomethane. The investigated BioSNG processes use wood chips as feedstock, are based on the dual fluidized bed steam gasification technology and the VESTA SNG process from Amec Foster Wheeler, and generate 6.1, 12.2, and 49.1 MW BioSNG. The techno-economic assessment shows that the biomethane processes have, in general, a lower break-even price for the generated natural gas substitute. However, their scalability is limited and at larger scale (49.1 MW BioSNG capacity), the BioSNG processes become competitive. The 1.0 MW biomethane and all BioSNG plants meet the 2018 renewable fuel directive of the EU. In contrast, the 4.8 MW biomethane process does not meet the directive as the feedstock, which is mainly based on energy crops, causes significant CH4 and CO2 emissions.Austrian Research Promotion Agency (COMET

CFY-stacks for use in stationary SOFC and SOEC applications

Fraunhofer IKTS and Plansee SE continuously develop SOFC stacks with Chromium based interconnects (CFY) and electrolyte supported cells based on Scandia doped Zirconia. This technology has a great potential for cost-effective manufacturing and rapid up-scaling due to availability of major stack components and essential improvements in manufacturing made last year. The stacks are already available on the market and are in test at several potential customers. The paper gives an overview of the current status of CFY-stack development focused on performance map and system cycling. The results of operation of CFY-stacks in modules with stacks working on different fuels with and without internal steam reforming in partial and full load are presented

Wood Gas Processing To Generate Pure Hydrogen Suitable for PEM Fuel Cells

A test campaign was carried out to generate renewable hydrogen based on wood gas derived from the commercial biomass steam gasification plant in Oberwart, Austria. The implemented process consisted of four operation units: (I) catalyzed water–gas shift (WGS) reaction, (II) gas drying and cleaning in a wet scrubber, (III) hydrogen purification by pressure swing adsorption, and (IV) use of the generated biohydrogen (BioH₂) in a proton exchange membrane (PEM) fuel cell. For almost 250 h, a reliable and continuous operation was achieved. A total of 560 (L_{<i>n</i> dry basis (db)})/h of wood gas were extracted to produce 280 (L_<i>n</i> db)/h of BioH₂ with a purity of 99.97 vol %_db. The catalyzed WGS reaction enabled a hydrogen recovery of 128% (<i>ṅ</i>_BioH₂)/(<i>ṅ</i>_{H₂,wood gas}) over the whole process chain. An extensive chemical analysis of the main gas components and trace components (sulfur, C_<i>x</i>H_<i>y</i>, and ammonia) was carried out. No PEM fuel cell poisons were measured in the generated BioH₂. The only detectable impurities in the product were 0.02 vol %_db of O₂ and 0.01 vol %_db of N₂