Catalyst polishing Flow scheme

This process is designed to sweeten small sour gas flows. The catalyst is an absorbent which removes H2S. Iron water is a waste product of a sewage plant. Gazpack has developed, in co-operation with manufacturers of sewage plants, an application that transforms the iron water into granular beads. These beads absorb the H2S from sour gas. Fe2O3 + 3 H2S to Fe2 S3 + 3 H2O. The process is not reversible and creates heat during absorption.

Catalyst polishing Flow scheme

The package consists of one compressor, a cooler, a scrubber and two towers with Sulago® beads.

To operate successfully the following precautions are necessary.

Design criteria:

  1. Diameter (low contact speed causes insufficient absorption).
  2. Height (crushing pressure)
  3. Two vessels (heat transfer)
  4. Stainless steel (hot H2S + H2O is aggressive)
  5. Drain water is acid, toxic and explosive in contact with water (dangerous: add water not inverse).

This system is suitable for small capacities (<1000 Nm3/h) and low H2S values (<250 ppmv H2S).

Production costs are high due to:

  1. The saturated absorbent is a chemical waste product and processing it as such is expensive.
  2. Cleaning of the vessel is dirty and risky work, environmental precautions are required.
  3. Price per kilo is high.

The waste absorbent is toxic and is easily flammable and should be stocked under a nitrogen blanket.

For higher capacities, the Sulaway ® system is the best choice. The investment costs are lower and the system is environment friendly. The H2S is transformed into acid water (0% H2SO4), which is marketable as an environmental friendly product.


Flare Desulfurization Whitepaper