SRU (sulfur recovery unit)

Sulphur recovery refers to the conversion of hydrogen sulfide (H2S) to elemental sulphur

(solid state)

Hydrogen sulfide (H2S) is a by-product of:

1. Processing natural gas and

2. Refining high-sulphur crude oils.

SRU (sulphur recovery unit)

The Claus process is the most significant gas desulfurizing process, recovering

elemental sulfur from gaseous hydrogen sulfide

First patented in 1883 by the chemist Carl Friedrich Claus

the Claus process has become the industry standard.

SRU (sulfur recovery unit)

The multi-step Claus process recovers sulphur from the gaseous hydrogen sulfide

found in raw natural gas and from the by-product gases containing hydrogen sulfide

derived from refining crude oil and other industrial

Gases with an H2S content of over 25% are suitable for the recovery of sulphur in

straight-through Claus plants while alternate configurations such as a split-flow set up

or feed and air preheating can be used to process leaner feeds.

SRU (sulfur recovery unit)

All sulphur recovery units (SRU’s) require some means of sealing the sulphur rundown

lines between condensers and temporary storage.

• The purpose of a sulphur sealing device is to prevent process vapour (with remaining

H2S and SO2) from escaping with liquid sulphur.

• Refineries and gas plants have two options for achieving a vapour seal in sulphur

rundown lines.

• One option is the in-ground device, commonly referred to as a conventional seal leg.

• The other option is an aboveground sealing device, often called a sulphur trap or

sulphur seal, which uses a float-trap design to seal an orifice.

• As an example, one of the largest US refineries (located in Houston, TX) has employed

both seal legs and above-ground sulphur traps.

• Based on experience with seal-leg plugging and the consequent downtime and costly

repairs, this Houston refinery embraced the concept of an above-ground sealing

device.

• However, the sulphur trap they implemented had its own issues.

• The refinery’s Consulting Engineer for Process Design and Technology reported that

the sulphur trap’s spherical float was prone to cracking, causing the unit to fail in a

closed position.

• The Consulting Engineer also reported issues with sealing integrity due to

misalignment of the float plug

• CSI came out with the solution of their above ground sulphur seal than can avoid all

the above issues

CSI above ground sulphur seal