The Competence in Dust Less Blends
In accordance with their name, the Dust Less Blends commonly have very low levels of dust associated with them. This leads to a numer of key benefits, particularly during the additive handling stages.
From a health safety viewpoint there is no risk of explosion resulting from a powder of dust dispersion in air. In addition, apart from a general improvement in plant hygiene, the use of DLB virtually eliminates the irritation and toxicity problems which face workers assigned ot handling operations.
The reduction in overall dust levels in a plant has several other benefits, for example, the risk of cross contamination of one type of additive with another is significantly reduced. For the same reason, the risk of the final polymer having quality problems is also much lower. The net effect is a contribution towards the consistency of the final polymer quality. A further benefit of the reduction in dust levels is that the cleaning of equipment betweeen campaigns or grades is substantially shorter (sometimes less than half of that when powders are used). This has a direct contribution to productivity as it means less equipment 'down time'.
Examples of products which are dusty in the powder form, have some health issues associated with them (irritant, harmful, toxic ...) or can cause cross contamination are sodium benzoate, nickel quenchers, fumed silica, some clarifiying agents, talc, HALS etc.
Finally, a very direct cost saving achieved when using DLB's rather than powders, or even granules, is in the amount of product lost via the dust extraction system during handling and feeding activities. Depending upon the exact nature of the powdered or granulated additive, an amount of between 1 - 7 % is usually lost into the extraction system in the form of dust. As additives are generally rather expensive relative to polymer prices, the use of an DLB can amount to a substantial cost saving.
In addition to the direct cost of the physical loss of additive powder there is an additional cost of disposal of the material which is caught in the extraction system. In Europe this cost can easily be of the order of US $ 550/T or more. Hence, for a polyolefin plant which uses around 2,000 TPA of additives, around 60 TPA of waste product due to dust extraction can be expected, which will have an associated disposal cost of over US $ 30,000.