In the present work, we carry out evaluation of gas flow maldistribution in different types of gas distributing devices (GDD) and packings by using experimental data for the output velocity profiles for both the absorption pilot column and industrial column. Two GDD construction types—with circular and with local tube gas feed, together with their modifications—are investigated. Two pilot columns—with random packing RSRM 1.5″ and with structured ceramic Honey-comb packing, and one industrial contact economizer with Honey-comb and inclined rings—have been studied. Six types of quantitative estimations of GDD and packings maldistribution are determined by the help of MATHCAD. Then, their sensitivity toward several factors, such as the type of GDD and packing, the initial gas flow velocity, the number and dimension of measuring cells on the column cross-section, the measurement error, and so on, is investigated. It is found that only two of the quantitative maldistribution estimations take into account the formation of maldistribution clusters, which deteriorates the uniform gas distribution. A novel method for quantitative determination of these clusters and also for identification of the zones at column cross-section, in which they appeared, has been developed. It is established that the measurement error and the dimension of measuring cell deeply influence the number, the area, and spatial distribution of these zones on the cross-section, as well as the values of maldistribution estimates.