Wellman-Lord procedure

The Wellman-Lord process is a regenerative process for flue gas desulphurisation . In addition to the lime washing process, this process has retained its importance, particularly at refinery sites.

In this process, the flue gases are passed through a scrubbing liquid made from sodium sulphite solution (Na ₂ SO ₃ ) in an exhaust gas scrubber . There the sulfur dioxide (SO ₂ ) from the flue gas reacts with the sodium sulfite to form sodium hydrogen sulfite .

${\displaystyle \mathrm {Na_{2}SO_{3}+SO_{2}+H_{2}O\rightleftharpoons 2\ NaHSO_{3}} }$

The washing liquor is freed from sulfur dioxide by heating in the regenerator. The remaining sodium sulfite solution is then fed back into the scrubber (absorber) (cycle process).

Pure sulfur can be obtained from the concentrated sulfur dioxide gas . Two thirds of the sulfur dioxide are reduced to hydrogen sulfide (H ₂ S) in a hydrogenation reactor with synthesis gas (produced by partial oxidation of natural gas) . The hydrogen sulfide is combined with the remaining sulfur dioxide and then converted into sulfur in three catalytic stages (see Claus process ). This process makes sense in those companies that have little or no hydrogen sulfide available from other sources (pure power plants ). Refineries have enough hydrogen sulfide from hydrodesulfurization plants. The expensive reduction step can be omitted here.

Individual evidence

1. ^ Worley Parsons: Total Sulfur Management - Capability and Experience ( Memento October 18, 2012 in the Internet Archive ). (PDF; 1.5 MB).