Sulfur Recovery Units
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The demands on these units have dramatically increased over just the last few years. The need to handle more sulfur along with the high cost of adding new equipment leads many to utilize oxygen enrichment to increase production. This normally results in higher operating temperatures that can have a significant impact on the refractory lining system. New emission limits prevent flaring of acid gas during unexpected outages which frequently results in reduced production through an entire refinery. The result is more severe operating conditions combined with a demand for reliability that old operating units and improperly designed new units cannot provide. Add to this the need in some plants to operate at times on air (low temperature) and when needed on oxygen (high temperature). These severe operating temperature swings combined with the vessel corrosion concerns creates complex thermomechanical issues for the refractory requiring careful consideration to maximize refractory reliability and performance.
Critical factors that can affect the reliability and life cycle cost of the refractory system can include:
- Air operation &/or O2 enrichment
- Vessel size or diameter
- Shape or geometry (ie: heads, cones, transitions, flat walls, etc)
- Lining construction
- Hotface material quality & thickness
- Backup material quality & thickness
- Shell corrosion points (high and low)
- Burner harmonics &/or flame impingement
- High temperature refractory deformation
- Checkerwall/choke ring construction details
- Material (science) selection
- Reducing atmospheres
- Shroud design
- Expansion accommodation (radially and linearly)
- Hoop stresses
- Keying action (self supported lining designs)
- Upset conditions (thermal and pressure related)
- Temperature measurement means (internal and external)
- Quality and skill of the installation
Reaction furnaces have the capability of melting the best refractory materials available today. This includes air operated units during upset conditions or uncontrolled operation. The goal is therefore to maximize the lining system beginning with the best materials available. Engineering considerations must be based upon the size, geometry and environments that are unique to each unit. Finally, the lining, as designed, must be installed properly. We call this the Three Keys to Reliability.
Thorpe has been designing and installing linings for Sulfur Recovery Units since the mid 1950’s.
Call Thorpe for a review of your refractory system
and for help identifying the weak links in your lining system;
the areas most likely to fail first.