Thermochemical analysis of a flue gas-driven biomass gasification

Abstract

One of the methods of obtaining energy from renewable sources is the technology of indirect cofiring of biomass. It consists in the gasification of secondary fuel and combustion of the generated gas in the boiler together with its primary fuel. The paper presents a thermodynamic analysis of the use of the boiler flue gases as the converting medium in the process of indirect co-firing - a technology which is being developed at the Institute of Power Engineering and Turbomachinery of the Silesian University of Technology. The basis of the analysis are the data resulting from variant calculations conducted with the use of the Gaseq program. The calculations were made for various compositions of gasified fuel and the converting medium, variable fuel/oxidiser ratios and variable gasification temperatures. As a result, the equilibrium composition and the calorific value of the generated gas were obtained. The main optimisation objective adopted here was the nondimensional efficiency coefficient, which is the ratio of the chemical energy of products to the chemical energy of the process reactants.

Numerical modelling of a stoker furnace operated under indirect co-firing of biomass

“…The gasification temperature established based on equilibrium-balance calculations (Litka et al, 2012) was determined taking account of two kinds of losses: the dissipation loss and the heat loss in slag. It is assumed that there is no heat exchange between the boiler and the gasifier through their structural elements.…”

“…The conversion of biomass into fuel gas makes it possible to avoid some technological problems which arise if the secondary fuel is used for energy purposes in other ways. A novel indirect co-firing concept which utilises flue-gas oxidiser has already been presented elsewhere (Litka and Kalisz, 2012) and the aim of present study is to further analyse the applicability of the novelty through CFD modelling.…”

Recommendations for the process of biomass and waste gasification in a rotary reactor

“…Research base on an idea of indirect co-combustion of waste and biomass in power boilers. The developed co-combustion technology was based on patent applications [2][3][4][5] and previous experience [6][7][8][9][10][11][12]. The solution claimed therein is presented on the diagram in Fig.…”