A grade of sulphur that is often used in industrial processes is the pellet or prill form of the element. Sulphur pellets are used in rubber vulcanization and the production of asphalt and bitumen, detergents, dyes, explosives, fertilizers, insecticides, and other products. Sulphur is also widely used as a bleaching agent in the production of paper. Safely conveying sulphur pellets and prills brings it own unique set of handling challenges.
How are Sulphur Pellets and Prills Produced?
Two recognized methods are used to produce sulphur pellets. In the air prilling method, molten sulphur is sprayed from the top of a tower into an upward flowing stream of air. As the droplets of molten sulphur fall, they cool into prills.
In the wet prilling method (known as the Enersul WetPrill™ process), molten sulphur is pumped onto a perforated tray and passes through the perforations to produce narrow streams of sulphur that fall into an agitated water bath. Pellets or prills form as the sulphur contacts the water. While in contact with the water, the sulphur pellets cool and harden. The solids settle to the bottom of the water tank and flow by gravity to dewatering screens where a high frequency vibrating screen separates out the pellets. The wet prilling process produces spherical, uniformly sized, low moisture pellets.
What are the Challenges in Conveying Sulphur Pellets and Prills?
Conveyors are used in the production of sulphur pellets as well as in facilities that use the pellets and prills as an input material into their own production processes.
Due to the characteristics of the material, conveying sulphur is both a critical and severe service application. Sulphur dust suspended in the air can ignite easily and explode. For this reason, facilities that handle sulphur are required to comply with stringent regulations for the safe handling of the material. Conveyors that handle sulphur pellets and prills should therefore be capable of containing combustible dust and suppressing and ignition sources (i.e., static charge accumulation) that could give rise to an explosion as the material is conveyed.
Sulphur pellets and prills are both extremely corrosive and abrasive, causing additional wear and tear on equipment. In this severe service environment, conveyors for sulphur pellets and prills must be designed and constructed to withstand prolonged exposure to the material. For this reason, stainless steel is the preferred construction material choice for conveyors handling sulphur pellets or prills.
Conveying Sulphur Pellets and Prills: Equipment
Equipment used to convey sulphur pellets and prills must be capable of handling material that is corrosive, potentially explosive, abrasive, and free-flowing. Bucket conveyors, such as the TipTrak™ Monocoque units, are often used within sulphur handling facilities where these requirements must be met.
Compliant to Atex zones 21 and 22, TipTrak™ Monocoque bucket conveyors are an ideal choice for the safe and gentle handling of solid sulphur product, including pellets and prills. TipTrak ™ Monocoque conveyors feature a fully enclosed and sealed gas-tight design that permits safe handling by mitigating the risks associated with product dusting and any resulting fugitive dust emissions that may result in an explosion. A polymer interlocking bucket assembly provides conductive continuous electrical grounding, while an explosion-proof motor and explosion vent panels where required provide additional safety and protection against the risk of explosion. In addition to these features, the stainless steel design of the TipTrak™ Monocoque conveyor provides protection against the effects of corrosion and abrasion resulting from exposure to elemental sulphur.
Where product integrity is a concern, TipTrak™ Monocoque units can gently move sulphur pellets and prills with no damage or degradation. The fully interlocking bucket design and rubber beltchain of TipTrak ensure that pellets or prills have a gentle ride through the conveyor with zero spillage along the way. TipTrak™ rubber beltchains can be made from rubber compounds especially formulated to resist degradation by elemental sulphur.
If you are conveying sulphur pellets and prills, UniTrak has the equipment and experience to move your material safely and efficiently. To find out more about UniTrak equipment options for handling sulfur pellets and prills, please contact our sales team directly.