GRAPHALLOY^®
Bushings and Wear Parts for Molten Sulfur Pumps

95% of all sulfur handling in North America is in a molten state. Typical applications for molten sulfur pumps include oil refineries, mining, sour natural gas and oil, sulfur re-melt piles, and truck or rail car loading and unloading.

GRAPHALLOY^® has various advantages for use in molten sulfur pump:

• Self-lubricating: GRAPHALLOY bushings are lubricated by the pumpage and need no additional lubrication. Graphalloy runs dry and keeps on running.

• Non-Galling: Permits closer running clearances between rotating parts resulting in lower shaft vibration. Survives high speed contact that would gall metal parts.

• High-temperatures: Iron grade Graphalloy operates to 750°F (400°C) - well beyond required temperatures for molten sulfur!

• Submerged: Maintains dimensional stability when submerged under load and over wide temperature swings. Provides constant running clearances. Will not swell.

Graphalloy Success Stories in Molten Sulfur Applications

Graphalloy Reduces Pump Vibration at a Petroleum Refinery:

There are eight vertical column pumps in this refinery's sulfur pit, four of which are "quite the trouble-makers" when it comes to high vibration. Vibration data usually indicates some sort of imbalance. Pumps were fitted with nickel-chromium (NI-Cr) bearings to handle the high temperature environment. To avoid seizing and galling, the line shaft and volute bearings were fit with 0.020-0.025' running clearance. However the pumps were experiencing high vibration, approaching 1.0 inches/second peak. When the pump was dissassembled, the bearing clearances had opened up to 0.030-0.034".

The pump was rebuilt using Iron Grade Graphalloy bushings with a shaft to bushing clearance of 0.006-0.007". The tighter clearances were possible due to the non-galling properties of Graphalloy. The overall high vibration level decreasead to a maximum of .21 inches/second peak. The pump worked so well that the refinery has since rebuilt three additional pumps to the same standards using GRAPHALLOY bushings.

Graphalloy Meets Molten Sulfur Pump Delivery Needs after a Hurricane Shutdown

Due to Hurricane Harvey, several large refineries in Texas/Louisiana had to shut down quickly. During the shutdown, tanks of molten sulfur cooled and solidified. The pumps that are used to transfer the sulfur to tank trucks for removal and sale also froze up. These pumps are normally always heated by steam jackets but when there is a sudden shutdown, they will freeze up. When the pumps freeze up, they have to be pulled and rebuilt.

GRAPHALLOY is a standard material for many types of molten sulfur pumps due to it's ability to handle high temperatures and dry run. The shop needed to repair the pumps quickly so they ordered iron-grade GRAPHALLOY bushings which were delivered within a few days of ordering.

They rebuilt 27 pumps in a 6 month period and Graphite Metallizing was able to expedite all of the GRAPHALLOY bushing shipments to meet customer target dates and get the refineries back up and running.

Click to download the informational sheet

Feb 27, 2020