Abstract: A relatively large volume horizontal liquid separation chamber is provided as an intermediate part of the downcomers used to transfer the denser liquid phase between contiguous trays of a countercurrent liquid-liquid extraction column. The downcomers also include two smaller vertical conduits which carry the liquid into and out of the opposing ends of the chamber. The downward flowing denser liquid phase is thereby subjected to a separation step within the downcomers to produce a stream of the less dense liquid released above the upper tray.

Abstract: A relatively large volume horizontal liquid separation chamber is provided as an intermediate part of the downcomers used to transfer the denser liquid phase between contiguous trays of a countercurrent liquid-liquid extraction column. The downcomers also include two smaller vertical conduits which carry the liquid into and out of the opposing ends of the chamber. The downward flowing denser liquid phase is thereby subjected to a separation step within the downcomers to produce a stream of the less dense liquid released above the upper tray.

Abstract: Water is removed from an alkaline solution used to extract relatively high concentrations of mercaptans from a hydrocarbon stream by stripping the alkaline solution with a hydrocarbon vapor stream. The vapor stream is then admixed with the oxygen-containing off-gas stream of the process to enrich the off-gas stream above its explosive limit.

Abstract: High efficiency in liquid-liquid extraction operations, such as extracting mercaptans from hydrocarbons with caustic, is obtained over a wide range of flow rates through a single extraction column by the provision of an intermediate product drawoff means located between a downstream section of extraction trays having greatest efficiency at low throughputs and an upstream section of trays having peak efficiency at high throughputs. A second product stream is removed after passing through the low flow rate trays and is blended with the stream from the intermediate drawoff means.

Abstract: Water is removed from an alkaline solution used to extract relatively high concentrations of mercaptans from a hydrocarbon stream by stripping the alkaline solution with a hydrocarbon vapor stream. The vapor stream is then admixed with the oxygen-containing off-gas stream of the process to enrich the off-gas stream above its explosive limit.

Abstract: High efficiency in extraction operations, such as extracting mercaptans from hydrocarbons with caustic, is obtained over a wide range of flow rates through a single extraction column by the provision of an intermediate product drawoff means located between a downstream section of extraction trays having greatest efficiency at low throughputs and an upstream section of trays having peak efficiency at high throughputs. A second product stream is removed after passing through the low flow rate trays and is blended with the stream from the intermediate drawoff means.