Recycling in a Paper Mill

You would think recycling in a paper mill would be very simple, but it can be difficult at times.  Most waste paper from the paper machine is recycled through the broke system.  However, there are areas where it is not feasible to feed the paper back to the broke system. 

I had the opportunity to optimize production in the converting area of a mill.  During this optimization I noticed that there was lots of waste generated in this area that could be recycled.  However, due to the mix of the paper and the location it was not ideal to sort the paper and feed it back through the broke system.  The trash bins contained a few layers of paper from the rolls that were to be converted, cores, core plugs, cardboard, and other general trash.

The core plugs can be easily recylced by simply sending them back the line to be reused.  The cores generally had some paper left on them and could not easily be sent back up the line to be used.  So I contacted a recycler to come and do a study to see if there was enough waste for him to install a baler and provide a trailer to load the paper waste.  His study concluded that the paper waste was of relatively good quality to him, and that he could install a baler and trailer at his cost and also pay the company for the paper waste that he was taking away to be recycled.  This was not a large sum of money, but we would have been happy with him simply installing the baler and taking the waste away.  The managers and employees were very happy with the result of the project.  After the baler was installed the employees no longer had to take the waste to the compacter.  The waste was compacted and baled on the floor which reduced the number of trips the forklift driver had to make from five or six per shift to just one or two.  The trip was also shorter since the trailer was placed closer than where the baler location. 

So look around for these opportunities.  Companies are looking to be more green and sustainable, why not get paid a little bit for it.  Just a thought.

Troubleshooting Tip: Sealed Sheet

I know it has been a while since my last post, but I'm still here.  I've just been busy.  Anyhow, without further ado, sealing the sheet can be a very big problem.  This is basically when the sheet is not draining properly.  It seals itself and does not allow the water to drain.  This problem can be quickly diagnosed by just looking at the sheet as it moves along the table. 

Once the situation has been assessed, what do you do?  There are several options.  The simplest thing to do is to remove some broke.  Broke contains lots of fines so reducing broke can alleviate the sealing.  Another thing you can do is refine less mainly with the hardwood refiners.  You can also adjust your furnish to increase softwood.

Those were the simple solutions.  If none of those options helped then you've got to dig deeper.  These are more machine specific options.  You can increase the amount of water going to the headbox.  This seems counter intuitive but in many cases this added water will create channels in the sheet to allow for improved drainage.  Another option is to adjust the jet to wire ratio.  This will change the fiber orientation which may help.  One more option is to adjust the slice position which will change the delivery angle.  This will effect other parameters such as the jet to wire ration, so be cautious when adjusting the slice.  This will change where the jet lands on the forming board as well.   Just be aware of the adjustments.  Remember these are machine specific and may not apply to all machines.

I hope that helps.  I know some of it is a little vague and general.  Consult your process engineer and wet end operators before making these changes.  They may have some insights that could prove useful in troubleshooting.