Dynamic characteristics of deposit fracture and impacts of operating pressure during sootblowing in the radiant syngas cooler

摘要

During the operation of entrained-flow gasifiers, the ash deposits located on the wall tubes in the radiant syngas coolers (RSC) reduce the heat transfer efficiency. Syngas sootblowing is an effective method to remove the slag deposits in the RSC. In this study, a 3D numerical model was developed by combining the cohesive zone method (CZM) and the coupled Eulerian-Lagrangian analysis to investigate the deposit fracture process in RSC during sootblowing. The quasi-static analysis using ABAQUS obtained the stress-strain curve of the slag sample, which agreed well with the experimental tests and provided the detailed mechanical parameters to the CZM model. The dynamic characteristics of deposit fracture were discovered. The main fracture occurred between 1.0 and 1.5 ms, and the shape of the fracture area was not round but elliptical. The RSC operating pressure (P) was also investigated. The study found that higher pressure led to lower fracture speed, longer sootblowing time, and more syngas consumption. Based on the same extent of deposit fracture, syngas consumption increased when P < 3.5 MPa, and the density of syngas (rho(syngas)) has a more significant influence on the syngas consumption than the velocity of sootblowing syngas flow (v(avg)), especially when the sootblowing time is small.