Investigation on the ash deposition of a radiant syngas cooler using critical velocity model

Abstract

Coal gasification technology is a very important industrial technology, in which the Radiant Syngas Cooler (RSC) plays a pivotal role in the heat storage and heat recovering process. Ash deposit in RSC is a critical factor which may seriously affect the performance of RSC or even result in a shutdown. Therefore, conducting research on the deposit process of RSC is extremely worthwhile. In this study, we create an RSC model with the application of an optimized Critical Velocity Model (CVM) and perform simulations using the CFD method. With the simulating method, we conduct a series of analysis to obtain a more detailed description of the ash distribution and heat transfer in the RSC. Research shows that the CVM proposed in this paper can be precisely applied to the heat transfer process in a RSC, and not only can this method obtain the distribution of ash deposit similar to other methods but also determine the conversion of the ash deposit thickness to heat resistance, which makes the forecast of the overall heat exchange more accurate. According to the study, the ash thickness changes with the vertical height of RSC. For the division wall and panels, the ash thickness increased from the bottom, and then reached a maximum value at about 2/3 of total height. Under the influence of ash deposition, the total heat transfer rate of RSC decreased by 10.4%, and the outlet temperature of syngas increased by 5.7%. This result can provide a reference for the predictive analysis of RSC.

Keywords

• Radiant syngas cooler
• Ash deposit
• CFD
• Critical velocity model