How replacing a choke ring with a VectorWall removed the vibration that capped a refinery sulfur recovery unit.
Vibration and noise set the limit on throughput, not the burner and not the boiler.
The cause sat in the middle of the furnace
In the Claus reaction furnace of a refinery sulfur recovery unit in Asia, vibration limited how much acid gas the unit could process while the furnace had a choke ring. After the choke ring was replaced with a VectorWall, the unit ran at higher capacity, destroyed ammonia better, and no more furnace vibration was observed. A later CFD study traced the vibration to how the flame and pressure waves behaved in front of the choke ring.
A Claus reaction furnace converts about two thirds of the sulfur in its thermal stage and destroys ammonia and hydrocarbons in the feed. Internals such as checker walls and choke rings are there to mix the gas and hold it at temperature long enough.
When those internals let the flow jet or pulse, the furnace starts to shake. Operators then hold back throughput to protect the furnace. Brick checker walls loosen and crack under the same vibration, and walls in that state make it worse.
The vibration was not a fault of the brick lining but of the flow, so the cure was a wall that shapes the flow instead of one that only stands in its way.
An independent engineering firm modeled the furnace with the choke ring and with the VectorWall for Blasch.
A VectorWall in place of the choke ring: interlocking hexagonal blocks, stacked without mortar, with vectoring tiles that turn the flow into a swirl with a long path and a narrow residence time distribution. The tiles also reflect radiant heat back into zone 1.
| Before, with choke ring | After, with VectorWall |
|---|---|
| capacity limited by vibration | higher acid gas throughput |
| ammonium salts in downstream equipment | better ammonia destruction |
| furnace vibration | no vibration observed |
The furnace no longer sets its own limit, and the throughput that was held back for vibration is available again. The wall itself has no mortar joints for vibration to work loose.
Hexagonal blocks with vectoring tiles that shape the flow in reaction furnaces.
The Claus process and the parts that decide how the thermal stage runs. Sulfur recovery
Temperatures and sour water stripper gas rates before and after a VectorWall revamp.
No. In this unit the CFD study linked it to the flame and pressure waves in front of the choke ring. Damaged brick walls can add to it.
In this furnace it lowered it, by about 900 Pa compared with the choke ring.
Yes. It is built into a slot in the lining or against the hot face, with a course of brick on each side, in the position of the old internal.
Send the furnace dimensions, the current internals and the feed composition. A Blasch engineer looks at the flow and at what a mixing wall could change.
