Gases ‘Containing H,S or both H,S and Co2 are commonly referred to as sour gases or acid
80388 in the llYQ‘fiamLprocessing industries.
The chemistry involved in the amine treating of such gases varies somewhat with the particular
amine being used. For one of the more common amines, monoethanolamine (MBA) denoted as
RNH» the chemistry may be expressed as:
RNl-I, + lbs RNH’+ SH‘
A typical amine gas treating process (the M35, as shown in the flow diagram
below) includes an absorber unit and a regenerator unit as well as accessory equipment. In the
absorber, the down flowing amine solution absorbs H,S and CO2 from the up flowing sour gas
to produce a sweetened gas stream (i.e., a gas free of hydrogen sulfide and carbon dioxide) as a
product and an amine solution rich in the absorbed acid gases. The resultant “rich” amine is then
routed into the regenerator (a stripper with a reboiler) to produce regenerated or “lean” amine
that is recycled for reuse in the absorber. The stripped W from the regenerator is
concentrated HIS and Co2.
3) For all applicable process parameters, perform a HAZOP study on the:
Re-boiler outlet (lean amine) to Absorber (lean amine)
b) What specific recommendations can you make to improve the safety of this system?