For heating the extrusion granulator in your facility, is steam or heat transfer oil used? And what is the effectiveness of each method?
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Powders such as polyethylene are heated and melted in an extrusion granulator, after which they are granulated and packaged. Which type of heat source is suitable for use in an extrusion granulator? Which one requires more investment? Which one is easier to maintain? What are the main issues involved?
I’ve never used steam heating; the investment cost for heat transfer oil is relatively high, but it’s more cost-effective in the long run
Steam heating is probably possible only when there is steam available on-site; steam isn’t available everywhere in large petrochemical plants
Steam also costs money; it represents an energy expense. Steam is quite expensive – 120 yuan per ton for 3.5-pressure steam
There is excess steam; using steam is the best option, but if that’s not possible, oil has to be used instead
Previously, small-scale PVC granulation used electric heating, while large-scale operations used steam heating. Currently, most cable factories use steam for heating; heat transfer oil is also an option, though the approval process is rather complicated
Why is it smart? Is it a fire safety issue?
Heat transfer oil requires a heat transfer oil furnace (or electric heating for the oil); given the current strict environmental regulations, it is difficult to obtain approval for such projects. We have now banned boilers with a capacity of less than 10 tons; those over 10 tons are required to be converted to gas boilers within a set deadline, and new coal-fired boilers are not approved for installation.
If an extruder is heated using hot oil, there is no need for an oil furnace; a dedicated hot oil system is used instead. Although using hot oil requires a higher investment, it allows for more stable temperature control. In contrast, steam-based temperature control is not as stable, especially when the steam traps do not function properly. This can lead to uneven temperatures in the die, as well as a situation where the die and cutting tool are not perpendicular to each other, which damages both the die and the cutting tool. The particles produced also end up having an unsatisfactory appearance.
Does that mean that imported extruders basically use a hot oil system?