Kelair supplied a Day pump to a major refinery in Australia. After pumping molten sulfur at 135̊C plus, they came back needing a replacement, 15 years after purchasing the initial pump.
Elemental sulfur is an amorphous yellow solid used as a raw material for manufacture of sulfur dioxide, sulfuric acid and related products. It is also used to formulate sulfur cement for some corrosive services.
When transporting Molten Sulfur in liquid form, it is important to take the liquid properties into consideration. Abnormal variations in viscosity only allow Molten Sulfur to be pumped satisfactory in the range of 135̊C to 155̊C.
Horizontal pumps have been used for this service but the success rate has been limited because of problems keeping the Sulfur in the stuffing box in the molten state. Vertical sump pumps with steam jacketing or heat tracing are ideally suited for this difficult application.
Labour Taber series is the pump of choice. Speeds of 950, 1450, or 2950 rpm are available depending upon the service conditions. Remember that a slower speed pump can be more competitive in this service because of the lesser intermediate bearings.
Our service condition was 360 LPM at 12m head. We selected a pump running at 1450 rpm.
The material of construction that is normally used with Molten Sulfur:
- Material of construction: All wetted parts should be constructed of Ductile Iron, 304 Stainless steel or all 316 Stainless steel. The impeller should be 304 or 316 Stainless steel. The support column and discharge pipe should be schedule 80 (not 40) steel pipe. The shaft should be cold rolled steel.
- Bearing material. All metallic bearings (typically Cast iron or Ductile iron) are required, with special clearances to allow for expansion and for the molten lead to flow between the shaft and sleeve.
- Couplings: all metallic non-spacer couplings (such as Falk Steelflex T20 or Thomas DBZ) are preferred because of the high service temperature.
The pump specification that Kelair has offered:
- Material of construction: Ductile iron casing, 316 Stainless steel impellers, wetted end parts with steel support column and discharge pipe.
To insure best reliability, Kelair offered non-witnessed performance tested in factory.
Kelair supplied the best technical support, sales support and customer service to the refinery, as we do to all our clients. This service is what keeps them coming back over and over again for more pumps.