Research on Ash Removal for the Water Wall of Coal Gasifier under Impact Loadings

Abstract

Vibration responses of the water wall of coal gasifier under impact loads were investigated. The influences of different diameters of water walls and impact loads on the effectiveness of ash removal were further considered. The results showed that the peak acceleration along the axial direction of the water wall is greater than 80% of the peak acceleration at the impact point when rapping devices are installed at the 1/4, 1/2 and 3/4 heights. Moreover, rapping devices should be staggered 30 degree in the hoop direction at different heights to avoid the dead zone of ash removal. Furthermore, vibration accelerations increase with increasing the diameter of water wall, while the impact time should be as short as possible for higher efficiency of ash removal.

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

“…Yang et al [ 21 ] developed a model to predict the particle sticking efficiency for ash deposition at high temperature and evaluated the sticking behaviours of synthetic ash in a drop tube furnace. Aimed to research the rapping ash effect, Zheng et al [ 12 ] considered the vibration responses of water tube under impulsive loads and investigated the influences of various diameters of water walls and impulsive loads on the effectiveness of ash removal. Jing et al [ 22 ] built a vibration model of a mechanical rapping ash‐removal device based on the one‐dimensional wave equation and deduced the displacement, velocity, and stress distribution of the stricken rod impacted by a transitive rod, according to the boundary conditions of the stricken rod.…”

“…Rapping ash removal instead becomes one of the effective methods with advantages of strong operability and high dependability. [11][12][13] The rapping action provides some striking for tubes, and then, the ash layer and tubes are influenced by the different-level inertia effect. The ash layer will be destroyed and split when the inertia force difference between the ash layer and the tube surface reaches the critical value.…”

Experimental and numerical modal analysis of wall tubes in the coal‐fired boiler or radiant syngas cooler

“…[1][2][3] The pressure in some high-pressure boilers and RSCs is high, and common cleaning methods such as steam sootblowing, acoustic sootblowing, and gas pulse cannot effectively remove slag deposits. [4] The overall layout and height of the whole wall tubes have some differences between the boiler and RSC due to different operating environments and types. The configuration of the wall tubes, including the shapes and fixation method, are similar between the two cases, and the material of the wall tubes is also the same.…”

“…The research on rapping‐off‐ash in the gasifiers is rare in literature. Zheng et al [ 4 ] investigated vibration responses of the wall tube in the coal gasifier under impact loads, and the influences of different diameters of wall tubes and impact loads on the effectiveness of ash removal were also investigated.…”

Study on the Stress Distribution of the Piston Rod Fillet Based on the Nonlinear Finite Element Method

“…Thus, the impact of the piston rod is more than the design value, the piston rod fracture often happens, leading to failure of rapping device. Through the analysis it was found that the stress concentration phenomenon is obvious in the fillet of the piston rod [2] . In order to further analyze the impact of fillet shape on the life of the piston rod, this paper simulated different fillet radius of the piston rod under the same load, study the force of the piston rod, and provide the basis to optimize the performance of rapping device.…”