Suggestions towards Energy-Saving for Refining at Stock Preparation

Abstract

In this paper, two topics are to be described how to reduce energy consumption at stock preparation. In general, refining process requires lots of electricity. Therefore, it can be mentioned that there are still some big possibilities left for energy-savings.
One of these two topics is newly developed conical type refiner (OptiFiner Pro). With its unique refining mechanism, the refining efficiency is highly improved by comparison with previous generation of conical refiners (for example, OptiFiner RF). Due to the high refining efficiency, we have experienced some installation cases indicating that previous generation of two or three conical refiners can be replaced by only one OptiFiner Pro. In addition, there is also one installation case that successfully ended by the replacement from conventional type of three double disc refiners with only one OptiFiner Pro. Our customers are satisfied with not only energy savings but also reduction of maintenance cost for stopped refiners. By choosing suitable fillings (i. e. refiner segments), OptiFiner Pro is available for virgin pulp refining (i. e. hardwood and softwood) as well as recycled pulp nowadays.
The other topic is refiner segments with much narrower bars and grooves than ones from conventional refiner segments. We have finally succeeded to manufacture these refiner segments (MicroBar) by casting and MicroBar is now widely used for hardwood refining at stock preparation as a good tool for energy-savings. The refining intensity of MicroBar is so high that the motor load for double disc refiners can be lowered by using MicroBar.
There is also possibility that one double disc refiner can be stopped from where there are two double disc refiners installed in series. For softwood refining, we have found a very effective pattern throughout test runs with a customer in 2014. This new pattern for softwood refining is also to be briefly described in this paper.