Simulation analysis of instantaneous impact on the radiant syngas cooler by rapping vibrators

Abstract

Slag or ash removal from water wall tubes in a radiant syngas cooler (RSC) is a routine task in operation, which can effectively increase the overall thermal efficiency. Rapping ash removal is one of the valid methods for shedding off the ash deposits in the high‐pressure surroundings of the RSC. In this study, the model of a real RSC was established by a numerical simulation based on the finite element software ABAQUS, and modal analysis and instantaneous response analysis (IRA) were researched to reveal the natural vibration characteristics of the RSC and aid the design of rapping ash removal. On the basis of the results of natural vibration characteristics and a subsequent harmony response, 16 Hz was set as the impact frequency, balancing off the vibrator number and the water‐tube displacement effect. It was indicated that ash deposit in the area around 1/2 longitudinal position was easy to remove due to great response to rapping action. Moreover, rapping at ½ position generally obtained greater displacement response in the whole RSC. A rapping design was proposed with six vibrators at the ½ longitudinal position and 16 Hz frequency, and then two rapping intervals were investigated comparatively. The case with a half‐cycle interval had a slightly larger response than the one‐cycle case, with a larger displacement in more circumferential tubes as well as with a greater sound pressure response in the RSC.

Optimization of a Sootblowing System for Effective Deposit Removal in Radiant Syngas Cooler Using Numerical Simulation

“…The primary approach to reduce the impact caused by deposition is through two aspects. The deposition and growth of slag on membrane wall surfaces can be minimized to control the operating temperature of RSC and use coal with lower ash content for gasification. , External mechanical forces can also be used to remove deposits on membrane walls through sootblowing, sonic soot cleaning, and vibrating tapping. − Sootblowers utilize high-pressure gas medium to achieve deposit removal by surpassing either the internal cohesion of a deposit or an adhesion strength between the deposit and membrane wall tubes. The sootblowing intensity is determined by factors including airflow velocity and pressure, sootblowing distance and angle, and nozzle shape and size.…”