Method for removing mercury from liquid hydrocarbon

Abstract

A process for removing mercury of the present invention is characterized in that an ionic mercury-containing liquid hydrocarbon placed in a container equipped with a circulating means is effectively contacted with a sulfur compound represented by the general formula (I): M1-S-M2 (I) wherein M1 and M2 may be the same or different and are each independently a hydrogen atom, an alkali metal or an ammonium group, by introducing the sulfur compound into a suction side and / or a discharge side of the circulating means while circulating the ionic mercury-containing liquid hydrocarbon into the container through the circulating means. By the process for removing mercury of the present invention, the ionic mercury is effectively removed from the liquid hydrocarbon in simple manner.

Description

[0001] The present invention relates to a process for removing mercury from a liquid hydrocarbon, and more particularly to an industrially useful process for removing an ionic mercury from an ionic mercury-containing liquid hydrocarbon placed in a container in a simple and efficient manner.[0002] As known in the art, natural gas liquid (NGL) recovered by removing liquefied petroleum gas from natural gases obtained from gas field contains mercury in an amount of from several tens to several hundreds ppb although it varies depending upon the production area. When such a liquid hydrocarbon containing mercury is used as a raw material for producing ethylene, etc., the activity of hydrogenation catalysts are reduced or the apparatus is corroded or it mechanical strength is reduced, because the mercury forms amalgams with platinum, palladium, copper or aluminum. For this reason, it has been strongly demanded to develop a technique for removing mercury from the liquid hydrocarbon.[0003] Ja...

AI Technical Summary

Benefits of technology

[0005] It is an object of the present invention to provide an industrially useful process for removing ionized mercury from an ionized mercury-containing liquid hydrocarbon using a specific sulfur compound in simple and effective manner.

[0021] In the process of the present invention, the ionic mercury-containing liquid hydrocarbon fed into the container is contacted with the sulfur compound of the formula (I) to convert the ionic mercury to a solid mercury compound insoluble to the liquid hydrocarbon. Then, the solid mercury compound is removed from the liquid hydrocarbon by filtration, sedimentation, etc. To efficiently contact the sulfur compound with the ionic mercury, the ionic mercury-containing liquid hydrocarbon in the container is circulated through a circulating means, while introducing the sulfur compound to a suction side and / or a discharge side of the circulating means. The circulating means comprises a pump which pumps up the liquid hydrocarbon by suction from the container and discharges the pumped-up liquid hydrocarbon into the container, and a conduit for passing through the liquid hydrocarbon. Generally, a suction inlet is disposed around the vicinity of the container bottom, and a discharge outlet is disposed around the vicinity of the container top. The circulating rate is preferably 1 to 5,000 m.sup.3 / h.

[0026] In the process of the present invention, the contact between the ionic mercury with the sulfur compound is further enhanced by mechanically stirring the liquid hydrocarbon in the container.

Problems solved by technology

Therefore, the proposed method is complicated in its operation and has drawbacks of requiring a complicated adsorbent preparation and strictly controlled operation conditions because of involving the adsorption process.