Increased capacity sulfur recovery plant and process for recovering elemental sulfur

A tubular Claus catalytic reaction unit for converting SO2 and H2S to elemental sulfur and water, said reaction unit comprising:

• a sulfur separator comprising a reactant gas channel and a process gas channel, said sulfur separator having a liquid sulfur outlet and at least one liquid sulfur inlet, said process gas channel having a process gas outlet;
• at least one concentric tubular reactor assembly disposed between said reactant gas channel and said process gas channel, wherein the concentric tubular assembly comprises:
• an annular Claus catalytic reaction zone in fluid communication with said reactant gas channel,
• an annular sulfur condensation zone adjacent to and in fluid communication with said catalytic reaction zone, for receiving reacted gases from said reaction zone and for condensing and collecting sulfur, said condensation zone comprising a process gas outlet in fluid communication with said process gas channel and said sulfur separator;
• and
• a temperature control zone in thermal communication with said condensation zone.