The environmental and safety concerns associated with unscheduled downtime are enormous.

How asset optimization gives your company an advantage

The chemical industry is mostly a process industry and geared drives are therefore to be found in pumping, agitation and extrusion applications. These applications are all three very different in their contribution to the process, but also have things in common. The loads and duty cycle for these applications usually are uniform and often times it is therefore wrongly assumed that not as strict of an optimization routine is needed. The environmental impacts and safety concerns associated with unscheduled downtime however are enormous and for this reason, downtime needs to be prevented at all cost and maintenance scheduled tight and just-in-time.  Another challenge is the great variety of complexity on-site. What a good optimization routine is, therefore differs asset to asset. It is very likely that a mix of all services that GBS offers, is needed.

Extruders deserve extra attention at a chemical plant. Single screw extruder gear units are usually parallel gear units with an additional lubrication system and a thrust bearing, to absorb reaction forces coming out of the process. In terms of maintenance tasks, these are very similar to those for a standard industrial gear unit, with some added attention to leakage and the thrust bearing. Extruder gear units are sensitive to process changes, for instance a lower product temperature which increases viscosity and therewith leads to a higher thrust force, or start up with residual and hardened material in the screw which results in a high breakaway torque. An optimization routine unfortunately cannot prevent these events from happening, but early detection of trends as results of these evens do have added value.

Twin-screw extruders, co- and counter rotating, are extra complicated in a way that the timing of the two screws needs to be very precise in order to produce a final product as homogenous as possible. In particular with counter-rotating extruders this is difficult, as these require an extra gear stage to mechanically change the rotating direction of one of the two screws. Twin-screw extruders are designed to match the center distance between the screws per customer specification and are for that reason often custom, resulting in long lead times on parts when ordered from the OEM. In particular the thrust bearing arrangement is special; typically there is one large bearing on the one shaft, and a series of smaller on the other. It is very important to frequently check the timing on the screws as mis-timing results in quality issues, as well as the condition of the thrust bearings for reliability purposes.

Soon, you will find success stories for chemical industry customers here.