Conference talk on investigating tar formation at low pressures in wood gasification systems, applying a novel thermo-chemical simulation model

Boiger, Gernot Kurt; Buff, Vincent; Zubiaga, Asier; Caels, Pedro

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DC Field	Value	Language
dc.contributor.author	Boiger, Gernot Kurt	-
dc.contributor.author	Buff, Vincent	-
dc.contributor.author	Zubiaga, Asier	-
dc.contributor.author	Caels, Pedro	-
dc.date.accessioned	2020-02-17T15:35:46Z	-
dc.date.available	2020-02-17T15:35:46Z	-
dc.date.issued	2019-11-18	-
dc.identifier.isbn	978-3-9503671-1-9	de_CH
dc.identifier.uri	https://digitalcollection.zhaw.ch/handle/11475/19478	-
dc.description.abstract	Introduction and Short Description: The method of gasifying wood via pyrolysis, gas purification, feeding a gas motor and producing electricity via a generator, has been applied for decades. Even-though wood gasification remains a promising technology regarding de-centralized sustainable energy supply, its main limitations, namely the issues of unsteady operation, excessive tar-formation and consequential high maintenance requirements, have never been fully overcome. In order to tackle these deficiencies and to increase the understanding of thermo-chemical wood-gas phase reaction dynamics, a numerical model has been created. After validating the simulator against comparable software, it has been applied to predict and thus understand tar-formation phenomena within a small experimental co-current gasification system. A particular focus within this work is laid on the investigation and minimization of tar-formation phenomena within low-pressure zones (e.g. downstream of valves) at temperatures T≤500K. Model-based analysis has led to a range of recommended process modifications to reduce the occurrence of tars. Methodology, Results and Discussion: The novel thermo-chemical wood-gas model is inspired by a unifying perspective on physical phenomena, based on Gibbs fundamental equation. The tool considers coal C(s), water H2O(v), methane CH4, carbon-dioxide CO2, carbon-monoxide CO, hydrogen H2 and tar represented by naphthalene C10H8 as interacting chemical species i. Within the applied simulation concept, any chemical reaction k such as, but not exclusively the hetero-/homogeneous Boudouard-, Methanation- or Water-Gas-Shift reaction is driven by non-zero molar Gibbs free energies of reaction ΔGR,k. The solver has been validated by comparison to a well-known approach based on minimizing global Gibbs free energy within a LaGrange function. Graphs compare respective results of calculated wood-gas equilibria compositions over a process-relevant temperature range, and clearly shows 1:1 correspondences between the solvers. Applying the solver and accounting for decreasing temperature and pressure along the wood-gas flow path, shifts in species concentrations can be qualitatively predicted. On this basis the following measures can be recommended to minimize tar occurrence in low-pressure zones: i) Decrease gas residence time and ii) increase temperatures. iii) Increase hydrogen to carbon ratio RH/C as well as iv) oxygen to carbon ratio RO/C in the wood gas, either by v) removing coal from the reaction zone or by adding either vi) water or vii) process air. Graphs show the comparison of three simulation runs where wood-gas with varying RH/C ratios is exposed to temperature and pressure drop. According to this prediction the amount of naphthalene decreases strongly at increasing RH/C. Conclusion and Outlook: The full paper will contain more detailed insights into the physical and methodical principles behind the dynamic wood-gasification solver and will provide more detailed insights into predicted gas compositions as well as investigations leading to the “recommendations for minimizing tar formation under low-pressure conditions” formulated in 2.	de_CH
dc.language.iso	en	de_CH
dc.rights	Not specified	de_CH
dc.subject	Wood gas	de_CH
dc.subject	Simulation	de_CH
dc.subject	Thermodynamics	de_CH
dc.subject	Tar	de_CH
dc.subject.ddc	540: Chemie	de_CH
dc.title	Conference talk on investigating tar formation at low pressures in wood gasification systems, applying a novel thermo-chemical simulation model	de_CH
dc.type	Konferenz: Sonstiges	de_CH
dcterms.type	Text	de_CH
zhaw.departement	School of Engineering	de_CH
zhaw.organisationalunit	Institute of Computational Physics (ICP)	de_CH
zhaw.conference.details	ICPS19 - 5th International Conference on Polygeneration Strategies, Vienna, 18-20 November 2019	de_CH
zhaw.funding.eu	No	de_CH
zhaw.originated.zhaw	Yes	de_CH
zhaw.publication.status	publishedVersion	de_CH
zhaw.volume	5	de_CH
zhaw.publication.review	Peer review (Abstract)	de_CH
zhaw.title.proceedings	Proceedings of the ICPS19 : 5th international conference on polygeneration strategies	de_CH
zhaw.webfeed	Chemieingenieurwesen	de_CH
zhaw.author.additional	No	de_CH
Appears in collections:	Publikationen School of Engineering

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Boiger, G. K., Buff, V., Zubiaga, A., & Caels, P. (2019). Conference talk on investigating tar formation at low pressures in wood gasification systems, applying a novel thermo-chemical simulation model [Conference presentation]. Proceedings of the ICPS19 : 5th International Conference on Polygeneration Strategies, 5.

Boiger, G.K. et al. (2019) ‘Conference talk on investigating tar formation at low pressures in wood gasification systems, applying a novel thermo-chemical simulation model’, in Proceedings of the ICPS19 : 5th international conference on polygeneration strategies.

G. K. Boiger, V. Buff, A. Zubiaga, and P. Caels, “Conference talk on investigating tar formation at low pressures in wood gasification systems, applying a novel thermo-chemical simulation model,” in Proceedings of the ICPS19 : 5th international conference on polygeneration strategies, Nov. 2019, vol. 5.

BOIGER, Gernot Kurt, Vincent BUFF, Asier ZUBIAGA und Pedro CAELS, 2019. Conference talk on investigating tar formation at low pressures in wood gasification systems, applying a novel thermo-chemical simulation model. In: Proceedings of the ICPS19 : 5th international conference on polygeneration strategies. Conference presentation. 18 November 2019. ISBN 978-3-9503671-1-9

Boiger, Gernot Kurt, Vincent Buff, Asier Zubiaga, and Pedro Caels. 2019. “Conference Talk on Investigating Tar Formation at Low Pressures in Wood Gasification Systems, Applying a Novel Thermo-Chemical Simulation Model.” Conference presentation. In Proceedings of the ICPS19 : 5th International Conference on Polygeneration Strategies. Vol. 5.

Boiger, Gernot Kurt, et al. “Conference Talk on Investigating Tar Formation at Low Pressures in Wood Gasification Systems, Applying a Novel Thermo-Chemical Simulation Model.” Proceedings of the ICPS19 : 5th International Conference on Polygeneration Strategies, vol. 5, 2019.