Abstract: A process for the purification of a fluid stream containing a sulphur contaminant, such as hydrogen sulphide, and mercury, phosphine, stibine, and/or arsenic compounds as a second contaminant wherein said fluid stream is passed through a bed of a particulate absorbent containing a sulphide of a variable valency metal, especially copper, that is more electropositive than mercury, to remove said second contaminant and then the sulphur contaminant is removed from at least part of the effluent from that bed by passing that part of the effluent through a bed of a particulate sulphur absorbent comprising a compound selected from oxides, hydroxides, carbonates and basic carbonates of said variable valency metal is disclosed. The removal of the sulphur contaminant converts said variable valency metal compound to the corresponding sulphide. The resulting bed of variable valency metal sulphide is subsequently used for the removal of the second contaminant.

Abstract: A double-loop process for the removal of specified gas or gases from a process gas by absorption with a liquid absorbent for said specified gas or gases wherein the process gas is contacted counter-currently in a first absorption stage with semi-lean absorbent liquid and then in a second absorption stage with lean absorbent liquid to give a sweet process gas and the absorbed gases are stripped from the laden absorbent liquid in a first stage giving a semi-lean absorbent liquid. Part of the semi-lean absorbent is recycled to the first absorption stage while the remainder is subjected to further stripping by counter-current contact with an auxiliary gas that has a concentration of the specified gas or gases that is lower than the concentration of the specified gas or gases in the process gas to give the lean absorbent liquid which is recycled to the second absorption stage.

Abstract: A process for the purification of a fluid stream containing a sulphur contaminant, such as hydrogen sulphide, and mercury, phosphine, stibine, and/or arsenic compounds as a second contaminant wherein said fluid stream is passed through a bed of a particulate absorbent containing a sulphide of a variable valency metal, especially copper, that is more electropositive than mercury, to remove said second contaminant and then the sulphur contaminant is removed from at least part of the effluent from that bed by passing that part of the effluent through a bed of a particulate sulphur absorbent comprising a compound selected from oxides, hydroxides, carbonates and basic carbonates of said variable valency metal is disclosed. The removal of the sulphur contaminant converts said variable valency metal compound to the corresponding sulphide. The resulting bed of variable valency metal sulphide is subsequently used for the removal of the second contaminant.

Abstract: Regeneration of an adsorbent bed on to which impurity compounds, e.g. sulphur compounds, have been adsorbed by means of a gas stream to desorb the impurity compounds. The gas stream containing the desorbed impurity compounds is then passed over a catalyst, e.g. a hydro-desulphurisation catalyst, effective to cause the reaction of at least some of the desorbed impurity compounds with hydrogen to give a reaction product which is then removed by absorption using a bed of non-regenerable absorbent. At least some of the gas stream is then recycled to the adsorbent bed undergoing regeneration. Hydrogen is added in approximately the stoichiometric amount required for the reaction with the impurity compounds before the regeneration gas enters the catalyst.