Fast-mode alternating cyclic operation in trickle beds at elevated temperature for foaming systems

An alternating gas/liquid fast-mode cyclic operation procedure was explored for reducing the occurrence of foaming flow regime in trickle-bed reactors at elevated temperature and moderate pressure. The effects of temperature and split ratio on the electrical conductance and pressure drop time series were analyzed for the air-aqueous cetyltrimethylammoniumbromide (CTAB) foaming and air-water systems. For the split ratios studied, it was found that fast-mode alternating cyclic operation could enlarge the operational domain of the low interaction regime at elevated temperature. Hence, increased reactor temperature was suggested to allow faster foam drainage and breakdown which was reflected in the lower pressure drop levels as well as in the faster collapse in pressure drop when the flow was switched from gas to liquid feed. Also, by adjusting the split ratios it was possible to reduce the two-phase pressure drops in cyclic operation below the levels corresponding to the equivalent barycentric constant-throughput operation.