Thermodynamic equilibrium analysis of entrained flow gasification of spent pulping liquors

Abstract

The main goal of this work is to investigate if thermodynamic equilibrium calculations can be useful for understanding and predicting process performance and product composition for entrained flow gasification of spent pulping liquors, such as black liquor. Model sensitivity to input data is studied and model results are compared to published pilot plant data. The high temperature and the catalytic activity of feedstock alkali make thermodynamic equilibrium a better predictor of product composition than for many other types of biomass and gasification technologies. Thermodynamic equilibrium calculations can predict the flows of the main syngas and slag products with high accuracy as shown by comparison with experimental data with small measurement errors. The main process deviations from equilibrium are methane formation and sulfur distribution between gas and slag. In order to study real process deviations from equilibrium, it is very important to use consistent experimental data. Relatively small errors in the model input, primarily related to fuel composition, can lead to grossly erroneous conclusions. The model sensitivity to fuel composition also shows that the gasification process is sensitive to naturally occurring feedstock variations. Simulations of a commercial-scale gasification process show that cold gas efficiency on sulfur-free basis can reach over 80 % and that greatly improved efficiency can be obtained by reducing ballast present in the form of water or inorganics.

Techno-economic feasibility study on the application of downdraft gasifier in small-scale red clay bricks industries

“…Moreover, the observed flame temperature confirms that the kiln could be kept above 800 °C for the verification of bricks (Phonphuak et al 2013). The average CGE is found as 68-79% which is on par with the values reported in the literature (Furusjö and Jafri 2018). Thus, the optimum operation of the gasifier and temperature inside the kiln were assured.…”

“…Cold Gas Efficiency (CGE) plays a vital role in the economic advantages of any application of biomass gasifier. Though the major performance parameters of the proposed system have been studied to check the experimental uncertainties, the procedure followed to calculate the error in CGE alone is taken in this study and presented as follows (Furusjö and Jafri 2018). m pg -mass flowrate of the producer gas CV pg -calorific value of producer gas m b -mass flowrate of the biomass CV pg -calorific value of biomass…”

Optimal Renewable Energy Distribution Between Gasifier and Electrolyzer for Syngas Generation in a Power and Biomass-to-Liquid Fuel Process

“…The Gibbs reactor block in Aspen Hysys is used for simulating gasification (GBR-100). As the entrained flow gasification occurs at high temperatures, the assumption of equilibrium for all reactions is reasonable, and the same Gibbs reactor was used in several studies in the literature to simulate the gasifier (Weiland, 2015;Jafri, 2016;Yakaboylu, 2016;Pala et al, 2017;Brachi et al, 2018;Furusjö and Jafri, 2018;Gambarotta et al, 2018;Hillestad et al, 2018;Naidoo, 2018;Ferreira et al, 2019;Khonde et al, 2019;Ostadi et al, 2019;Safarian et al, 2019;Tauqir et al, 2019). Devolatilization is endothermic, and the heat duty required will be supplied from the gasifier.…”

Slag Formation during Entrained Flow Gasification: Calcium-Rich Bark Fuel with KHCO3 Additive

“…Thermodynamic equilibrium calculations on alkali-enriched fuels aiming to predict slag properties have been previously published , and sodium has received significant focus, especially in regard to black liquor gasification. − Similarly, slag removal when using calcium rich fuels could in theory be achieved by forming large amounts of low-viscosity potassium–calcium carbonates at relatively low reactor temperatures. Publications from empirical studies of such carbonate formation in entrained flow gasification are scarce whereas the silicate system has been published by several groups. , …”