Claus process

The Claus process is a process for the industrial production of sulfur from hydrogen sulfide. Hydrogen sulfide produced, for example in the production of coke as a part of the coke oven gas, or in the desulfurization of crude oil in refineries. The process was patented in 1883 by the scientist Carl Friedrich Claus from Marburg ( worked in Middlesbrough and London).

Chemical Reaction

The basic chemical process consists of two steps:

Process engineering

The technical process can be divided into four stages:

Compliance with the stoichiometry is extremely important, otherwise excess SO2 or H2S (hereinafter Incinerator burned to SO2) pollutes the environment.

To increase the degree of sulfur removal further, various methods have been developed to clean the exhaust gas downstream of the catalytic levels of sulfur compounds. The most famous is the so-called SCOT process (Shell Claus off-gas Treating ).

SCOT process

SO2 which has not been converted to sulfur in the Claus process, is hydrogenated in the SCOT process for H2S:

And together with the unreacted H2S also the second catalytic step removed via amine scrubbing of the exhaust stream. The absorbed H 2 S is released and returned again to the use of the Claus plant. The exhaust gas is then due to the - also burned traces of H2S - albeit small. A good degree of sulfur removal Claus / SCOT combination is 99.8 %.

Regenerative FGD

In regenerative process for flue gas desulfurization (eg, Wellman - Lord process ) is formed SO2, which can be fed directly into an (existing) Claus plant. This additional investment for SO2 workup ( hydrogenation) is saved. Especially for refineries this is an interesting solution.