Claus plants in refineries process concentrated hydrogen sulphide (H2S) fractions converting them into elemental sulphur. They can also remove pollutants, particularly by decomposing ammonia.
Stricter environmental regulation leads to products with lower sulphur content. As a result Claus plant loadings with hydrogen sulphide and ammonia are increasing and the Claus plant may become a bottleneck.
The problem can be overcome by oxygen enrichment of the combustion air. This increases the capacity significantly. A new type of burner ensures excellent mixing of hydrogen sulphide and oxygen enriched air over a wide load range.
Benefits of oxygen enrichment:
- Increased Claus plant capacity
- Increased productivity without changing the pressure drop
- More effective treatment of ammonia containing feeds
Less effort for tail gas purification (reduced nitrogen flow)
The Double Combustion process illustrated here has been operating since 1990 at KOA Oil, Japan.
A novel approach has used the benefits of a multi-pass Waste Heat Boiler (WHB) for plants with restricted plot space. The zone between the first and second passes of the boiler is utilised as the second reaction furnace of the Double Combustion process.
Oxygen enrichment levels
