Geometrical features of corrugated structured packings

Corrugated structured packings are fabricated from thin, corrugated (crimped) metal sheets, arranged in parallel to each other. The surface of the corrugated sheets can be grooved, lanced, textured, or smooth. The corrugated sheets may be perforated or unperforated. The corrugated sheets are assembled into an element, typically 8 to 12 in talL The sheets in each element are arranged at a fixed angle to the vertical. Adjacent elements are rotated so that sheets of one element are at a fixed angle to the layer below. Table 8.1 contains geometrical data for several corrugated packings.

Crimp geometry (Fig. 8.9). The crimp size defines the opening between adjacent corrugated layers. The smaller B, h, and S are, the narrower the openings, the more sheets (and therefore, more surface area) per unit volume, and the more efficient the packing. On the other hand, narrowing of the interlayer openings reduces void space and reuses resistance to gas upflow, leading to a lower capacity and to enhanced sensitivity to plugging and fouling.

The relative ratio of B to h, S to h, and the crimp angle (angle between side S and base B) define the geometry of the flow channel and of the vapor-liquid contact zone. This geometry stays relatively uniform within a single packing family, but varies from one packing family to another. Crimp angles vary from 28 to 45° and base-to-height <B-to-h) ratios range from 2:1 to 4:1. In some packings, the sides of the triangle shown on Fig. 8.9 are rounded, giving a round top apex, Rounding of the triangle apex reduces friction and prevents concentration of liquid at the corners (27).

Triangular cross section

Triangular cross section

(a) Flow channel cross section

(t>) Flow channel arrangement

Figure 8.9 Crimp geometry in structured packings. (a) Flow channel cross section; (b) flow channel arrangement. (From J. R. Fair and J. L. Bravo, Chem. Eng. Progr., January 1990, p. 19, reproduced courtesy of the American Institute of Chemical Engineers.)

(t>) Flow channel arrangement

Figure 8.9 Crimp geometry in structured packings. (a) Flow channel cross section; (b) flow channel arrangement. (From J. R. Fair and J. L. Bravo, Chem. Eng. Progr., January 1990, p. 19, reproduced courtesy of the American Institute of Chemical Engineers.)

table 8.1 Geometric Characteristics of Common Metal Corrugated-Sheet Structured Packings

Crimp geometry Element geometry table 8.1 Geometric Characteristics of Common Metal Corrugated-Sheet Structured Packings

Crimp geometry Element geometry

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