A semi-empirical approach to the thermodynamic analysis of downdraft gasification / Svishchev Denis A.,Kozlov Alexander N.,Donskoy Igor G.,Ryzhkov Alexander F. // FUEL. - 2016. - V. 168, l. . - P. 91-106.

ISSN/EISSN:

0016-2361 / 1873-7153

Type:

Article

Abstract:

For most commercial biomass gasifiers the cold gas efficiency makes up 50-70\%. However, thermodynamic modeling demonstrates the possibility of its increase to 80-85\%. Thermodynamic models predict an optimal composition of flows coming to the gasifier, and a temperature. These parameters are hard to reproduce at gasifier since they often depend on the operating parameters. This paper proposes a semi-empirical approach which makes it possible to carry out a thermodynamic analysis of operating parameters and optimization of gasifier operation. To test the approach we did experiments on charcoal and biomass gasification in a downdraft gasifier. Modeling was done on a non-stoichiometric model maximizing the reaction system entropy. The semi-empirical approach reveals three limitations of the cold gas efficiency of the experimentally observed process. The first limitation is related to the attainment of a carbon boundary line ( which is estimated thermodynamically) by the reaction system. This line corresponds to the maximum cold gas efficiency of the process. The second limitation deals with a shift along the carbon boundary line. The third limitation is a stoichiometric limitation on the formation of combustible gas components. The process of wood gasification is characterized by a number of phenomena which are untypical of the downdraft process. These phenomena underlie the hypothesis about the wood gasification mechanism. According to this hypothesis the process of gasification runs in the layers of individual particles. At the same time there is either no fuel bed stratification or it does not manifest itself. (C) 2015 Elsevier Ltd. All rights reserved.

Author keywords:

Equilibrium model; Semi-empirical approach; Carbon boundary point; Downdraft gasifier; Cold gas efficiency; Biomass gasification mechanism FIXED-BED GASIFICATION; CIRCULATING FLUIDIZED-BED; 2-STAGE EQUILIBRIUM-MODEL; BIOMASS GASIFICATION; STEAM GASIFICATION; AIR GASIFICATION; CO-GASIFICATION; PILOT-PLANT; GASIFIER; GAS

DOI:

10.1016/j.fuel.2015.11.066

Web of Science ID:

ISI:000366758300013

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	MAR 15
Publisher	ELSEVIER SCI LTD
Address	THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND
Language	English
EISSN	1873-7153
Keywords-Plus	FIXED-BED GASIFICATION; CIRCULATING FLUIDIZED-BED; 2-STAGE EQUILIBRIUM-MODEL; BIOMASS GASIFICATION; STEAM GASIFICATION; AIR GASIFICATION; CO-GASIFICATION; PILOT-PLANT; GASIFIER; GAS
Research-Areas	Energy \& Fuels; Engineering
Web-of-Science-Categories	Energy \& Fuels; Engineering, Chemical
Author-Email	denis.svishchev@gmail.com kozlov@isem.irk.ru donskoy.chem@mail.ru af.ryzhkov@mail.ru
ResearcherID-Numbers	Ryzhkov, Alexander/C-3477-2016 Donskoy, Igor/K-5586-2014 Kozlov, Alexander/A-7267-2014
ORCID-Numbers	Donskoy, Igor/0000-0003-2309-8461 Kozlov, Alexander/0000-0002-5983-5884 Ryzhkov, Alexander/0000-0002-0555-7196 Svishchev, Denis/0000-0002-8454-2063
Funding-Acknowledgement	Russian Science Foundation {[}14-19-00524]; Russian Foundation for Basic Research {[}14-08-31666]
Funding-Text	Thermodynamic calculations for gasification processes were carried out at UrFU and supported by the Russian Science Foundation by Grant 14-19-00524 (to D.A.S., I.G.D. and A.F.R.). The other parts of the study are funded by the Russian Foundation for Basic Research (Grant 14-08-31666). Instrumental studies are supported by Baikal Analytical Center of Irkutsk Scientific Center of the Russian Academy of Sciences.
Number-of-Cited-References	84
Usage-Count-Last-180-days	6
Usage-Count-Since-2013	36
Journal-ISO	Fuel
Doc-Delivery-Number	CY9WY