Dynamic Modeling of Ash Deposition Growth Based on Comprehensive Melting Mechanisms in a Radiant Syngas Cooler

The dynamic variations in the melting characteristics of ash particles and deposition surfaces pose significant challenges to accurate ash deposition prediction in the radiant syngas cooler (RSC) of entrained-flow coal gasification systems. In this study, by integrating the melting behaviors of ash particles and deposition surfaces, a dynamic ash deposition model (P–W model) incorporating a viscous surface growth mechanism was developed based on one-dimensional energy conservation. The morphology and evolution of ash deposition were investigated, with further analysis on the influence of syngas temperature and wall temperature on deposition characteristics. The simulation results exhibit an agreement with experimental data, with the P–W model demonstrating a calculation error within 13% and a prediction accuracy exceeding twice that without the P–W model. The deposited morphology correlates with flow field distribution, with primary deposition initiating in the stagnation deposition zone and extending to the circumfluence deposition zone. The maximum deposition thickness achieves dynamic equilibrium during the midsimulation periods, fluctuating near 14 mm under the basic conditions. Industrial ash deposition layers exhibit distinct stratification characteristics attributed to dynamic variations in the melting characteristics of the deposited surface, accompanied by angular-dependent thickness distribution patterns that are consistent with simulation predictions. Rising syngas and wall temperatures accelerate the initial ash deposition stage. The influence of syngas temperature on ash deposition is more significant than that of the wall temperature, particularly in deposition thickness and affected zones. The research provides a theoretical reference for dynamic ash deposition prediction in a high-temperature environment of industrial RSC.s.