Removal of oxygen from feedwater is of paramount importance for safe boiler operation. Insufficient extraction of oxygen in deaeration vessels will lead to limited efficiency of oxygen scavengers and unsafe plant operation. The presented sizing procedure for packed deaeration columns is based on the similarity theory between heat and mass transfer and existing procedures. The goal of the proposed technique is not to achieve optimization of column dimensions, but to ensure that there is no undersizing of the packing height. This approach is justified considering the relatively low capital costs of deaeration columns in boiler plants. The proposed equations are based on an experimental setup involving several hundred operating regimes which have been verified and confirmed to have a high degree of accuracy.
Method presented in the paper is a reconsideration of the already published equations for a quick and reliable verification of experimental results related to direct contact condensers with zero vapor outflow. Both original and reconsidered methods presented by the author are confirmed by a large number of experimental data (more than 1250 total data points) which took over one decade of experiments on four different column types. Both methods draw the background in sound and simple theory and should be considered as very reliable while easy to use in practice.
Paper presents new equations for calculation of stress intensification factors, sustained stress indices and flexibility factors for large diameter-to-thickness ratio elbows (i.e.,[Formula: see text]). The proposed equations overcome the need for pipe stress engineers to use numerical analyses in order to evaluate the piping which falls outside of the scope of typically used piping design codes. Regression analysis of the newly proposed equations is based on an extensive numerical database developed specifically for purposes of this paper, alongside with the data (both numerical and empirical) found in the open literature. Proposed equations prove to be a better fit to the database than the existing equations and have been shown to be applicable not only for large pipes, but also for normal piping (having[Formula: see text]) typically found in industrial plants. In case of the adoption of the proposed procedure, it is implied that the proposed equations should be applied to all the bends within a piping system subject to the analysis and not only to the selected bends.
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