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 Sulfur Recovery Talk about a Tough Application!! Imagine designing a gas tight - zero emissions, high temperature, high pressure blower for intermittent duty which must handle toxic gas and which must be capable of being brought on line immediately upon demand! Here's the story: Hydrogen Sulfide (H2S) is a major source of elemental sulfur. In high concentrations, it can be lethal! It occurs in natural gas, crude oil, volcanic emissions, and certain mineral springs. In the oil refining process its presence is undesirable, therefore it must be removed. The Clause Process is one method used to remove the hydrogen sulfide, and while doing so, recover elemental sulfur. This process requires an HPRB exhaust blower with the following requirements:
These are special features we must provide: Casing Double walled construction. Steam flows between the walls to maintain a uniform 285°- F. gas temperature inside the fan. Below 285°- F. the sulfur will change from a gaseous to a solid state and will "freeze" to the blower surfaces. Build-up on the blower will occur, causing damage or destruction. Then a costly, time consuming cleanup is necessary to remove the solid sulfur and repair or replace the blower. Our unique steam jacketed construction prevents this from happening! Shaft Seal Because care must be taken to avoid local cooling, even the mechanical shaft seal is heat traced and purged with air or nitrogen. Centerline Support Assures tight tolerances between the shaft and shaft seal will be maintained. The housing is supported at the centerline, and grows concentric to the fan shaft when exposed to heat. Since this support isolates the housing from the drive and mounting bases, housing thermal growth does not cause forces to be applied to these bases. Thus alignment of the drive train is always maintained even when thermal excursions occur.
To prevent the shaft from taking a permanent set when the blower is idle but still exposed to the high temperature, a turning gear can be provided to keep the blower rotating at a very slow speed—usually 25 to 30 rpm. This slow rotation prevents thermal distortion of the rotor so the fan can be brought on stream at full speed without undue vibration. A recent trend is the use of a variable frequency drive which can be set to operate the blower at low speed when it is taken off stream. The VFD precludes having additional elements in the drive train as would be present with a turning gear arrangement (double extended main motor shaft, clutch coupling, gear train and motor and interlocking controls) which are costly and may present alignment and balance problems.
Careful analysis is performed for the selection of high strength steel rotor material to assure that the proper mechanical properties are maintained even at elevated temperatures. Testing: 1. Since gas tight construction is essential, IBI tests the housing twice to verify the soundness of the welds, and to assure there are no leakages at the flanges. First, a pneumatic test is performed using 15-150 psi air. Then, the housing is hydrostatic tested to 1 1/2 to 2 times the design pressure. 2. Shaft tolerances are closely monitored during machining. 3. Wheel is statically and dynamically balanced. 4. After complete assembly, fan is RUN TEST to verify no interference between stationary and moving parts, balance is acceptable and bearing temperatures are within acceptable limits. We developed this design in 1985 and have successful installations at many plants including Exxon, Marathon, Aramco, and Mobil Oil facilities. We maintain an edge over the competition with this special HPRB! They usually offer two stage blowers which are more costly and less efficient. Illinois Blower—the fan company which makes it easy for customers with tough applications!
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Turning Gear
Design Analysis