Structured Packing for TEG Contactors - design methods and operating characteristics

Presented at 9th Continental Meeting 14 May 1992 by

P Collins and K Breu, Sulzer Brothers Ltd.

The commonest and generally best way of drying gases is absorption using TriEthyleneGlycol (TEG). Increasingly stringent process requirements, such as ever-lower operating pressures arising from marginal recovery, and the constant search for weight reduction in off-shore operations, require selection of the optimal hardware for this process, and the minimisation of uncertainties associated with its design. In recent years structured packing has become the most-frequently chosen such hardware. The factors underlying this development, and the considerations associated with design for structured packing, are addressed here. Methods/guidelines for determination of column diameter and packed height are introduced in Section 2. In determination of packed height the question arises as to which equilibrium data from the several mutually inconsistent sets in the literature to use; this is discussed in section 3. Current developments aimed at reducing the degree of empiricism, and hence uncertainty, in determination of packed height, are outlined in section 4. Section 5 describes the operating characteristics of structured packings in TEG service. The aspects addressed are the hydrodynamics (capacity/diameter), holdup, glycol losses, plugging/fouling, flexibility (turndown), and column motion. Correct distribution of liquid and gas is crucial to performance of structured packing to its full potential; the hardware to achieve this, and other aspects of column internals construction, are considered in section 6. The conclusions drawn are presented in section 7.