Numerical simulation of GSP gasifier under different swirl angles

Based on chemical equilibrium assumption, a comprehensive three-dimensional numerical model was developed for a GSP gasifier. The Euler-Lagrange approach was applied to describe the multiphase flow in the reactor. The mixture fractions were used to describe the thermochemistry. The probability density function (PDF) of beta-function was used to model the turbulence-chemistry interaction. The stochastic tracking technique was used to model turbulence-particle motion interaction. The predictions were in good agreement with design and other's results, demonstrating the reliability of the model. The simulation results showed that the flow field of the GSP gasifier can be divided into four regions: swirling jet, internal recirculation, external recirculation and plug flow. Oxidation reactions mainly occurred in the swirling jet region and upper part of the internal recirculation region. Gasification reactions dominated the other regions. Unlike the flame profile of the GE Texaco gasifier, the high temperature ''V''-shaped flame directly impinged on the chamber wall (at a height point approximately 1/3 of the gasifier); as such, protection of the refractory at that position was also taken into consideration. In order to optimize the structure of the nozzle, different swirl angles were studied. As the angles increased from 0 degrees to 60 degrees, the flow field of the gasifier changed from the straight jet to the swirling jet. Because of the temperature profiles and DPM distribution, the carbon conversion increased with the increasing swirl number. Therefore, the structure of the nozzle is crucial to the performance of GSP gasifier. (C) 2015 Elsevier Ltd. All rights reserved.