Purification process

A cyclic process to remove pollutant from fluid which comprises at least three concurrent steps:

• (a) passing input fluid comprising pollutant through at least one adsorber to produce a polluted adsorber and a purified fluid stream of reduced pollutant content, which leaves the adsorber, stopping the flow into said adsorber to leave residual fluid therein, and separating said residual fluid from said adsorber to leave the polluted adsorber of reduced residual fluid content;
• (b) heating a polluted adsorber with a heated regeneration gas to produce a hot adsorber of reduced pollutant content and cooler regeneration gas of increased pollutant content;
• (c) contacting a heated adsorber of reduced pollutant content with a regeneration gas of a lower temperature than that of said adsorber to produce a cooler adsorber and a warmer regeneration gas, which gas is further heated to produce said heated regeneration gas which is passed to step (b);
• said process comprising at least 3 adsorbers, at least one of which is being subjected to step (a), at least one different adsorber to step (b) and at least one further different adsorber being subjected to step (c), and after completion of one step the adsorber produced is subjected to the next step in the cyclic sequence (a)-(b)-(c)-(a).