A method for heat integration in a sulfur recovery unit, the method comprising the steps of reacting the acid gas stream and the air stream in the reaction furnace to produce a reaction effluent, where the reaction effluent comprises elemental sulfur, reducing the temperature of the reaction effluent in the heating extension to produce an effluent stream, reducing the temperature of the reaction effluent in the waste heat boiler to produce a cooled effluent stream, reducing the temperature of the cooled effluent in the sulfur condenser to produce a liquid sulfur stream and a cooled gases stream, where the liquid sulfur stream comprises the elemental sulfur, and increasing a temperature of the cooled gases stream to produce a hot gases stream, where the heating extension is configured to capture heat from the reaction effluent and release the heat to the cooled gases stream.

The present invention is directed to a process for the removal of aromatic hydrocarbons from a lean acid gas containing less than 20 mol. % of H.sub.2S, comprising:

a) contacting the lean acid gas stream (1) with a H.sub.2S-selective liquid absorbent solution (29) in a first absorption zone (2) to produce a gas stream depleted in H.sub.2S (3) and an absorbent solution enriched in H.sub.2S (4),

b) introducing the absorbent solution (4) into a non-thermic stripping zone (8) where it is contacted with a stripping gas stream (7) to obtain an absorbent solution depleted in C.sub.4.sup.+ aliphatic and aromatic hydrocarbons (9) and a stripping gas stream enriched in aromatic and C.sub.4.sup.+ aliphatic hydrocarbons (10),

c) contacting the stripping gas stream (10) obtained in step b) with a H.sub.2S-selective liquid absorbent solution (28) in a second absorption zone (12) to obtain a stripping gas stream depleted in H.sub.2S (13), and an absorbent solution enriched in H.sub.2S (14)

d) introducing the absorbent solution (9) obtained in step b) into a desorption zone (16) wherein the H.sub.2S-selective liquid absorbent solution (17) is recovered and a lean acid gas is produced.

Sour syngas treatment apparatuses and processes for treating a sour syngas stream are provided herein. In an embodiment, a process for treating a sour syngas stream that includes sulfur components and carbon dioxide includes absorbing the sulfur components and carbon dioxide from the sour syngas stream in a primary liquid/vapor phase absorption stage with a solvent to produce a liquid absorbent stream. The liquid absorbent stream includes the solvent, the sulfur components, and carbon dioxide. A portion of the sulfur components from the liquid absorbent stream is directly oxidized in the presence of a direct oxidation catalyst to produce elemental sulfur and a recycle stream. The recycle stream includes an unconverted portion of the sulfur components and carbon dioxide. The recycle stream is recycled for further absorption of the unconverted portion of the sulfur components and carbon dioxide through liquid/vapor phase absorption.