Pencil "Lead" from Generator Brushes
by Justin Thomas, Virginia on 10.19.05
Tokyo Electric Power (TEPCO) and Tombow Pencil recently announced that they have jointly developed mechanical pencil "leads" recycled from generator brushes used in TEPCO's thermal power plants. Generator brushes are made from highly pure graphite (over 97 percent), and are crushed to form graphite particles. Generator brushes transmit electricity to rotating shafts and must be replaced on a regular basis because they get worn out from friction with the rotating shafts. Discarded brushes used to be disposed of as industrial waste in landfill.
Having examined the cost and effectiveness of recycling generator brushes, TEPCO decided to recycle the brushes into mechanical pencil leads in collaboration with Tombow. TEPCO estimates that about 300kg of used brushes are replaced in its thermal plants annually. Recycling all these brushes could produce 24 million refill leads (1.5 million packages of 16 leads each). Tombow plans to put the recycled leads on the market during 2005. :: Triple Pundit and Japan For Sustainability
I have to wonder why they don't adopt proper sustainability protocol. They should process worn-out brushes back into new brushes. The pencil lead approach is really just down-cycling, it doesn't prevent this commodity from going to landfill, it only postpones it.
To answer "Theyjust Dontgetit", I'm not sure you get it either. If Generator brushes aren't turned into pencil lead, you get twice as much waste, as pencil leads are otherwise made from 'new' carbon. Recycling them into pencil leads reduces the amount of 'new' carbon used.
Okay, now how do we get it? I went to their site and there is no way to order it yet. Please advise. Also, does anyone look at how bad is pencil lead in the first place? Is there a healthier source to lead?
_-_sheepdan: They'd generate twice as much carbon waste 'only' if they maintain status quo. However, this is not what I proposed (re-read my second sentence). We're discussing two options for old brushes: 1) Make old brushes into new pencil leads, using new carbon to make new brushes. 2) Make old brushes into new brushes, using new carbon to make pencil leads. Either option yields the same volume of waste carbon (whether graphite is recovered from recycled paper or not). The biggest difference lies in how each commodity is processed. Which process requires more energy, new pencil leads or new brushes? Which has higher emissions? Which generates more solid waste? If Tepco moved toward a brushless design, they might achieve even better overall lifecycle costs. Unfortunately this would likely be rejected due to considerable capital expense. _-_-_-_-_-_- Dorrie Grace: The name "lead" is actually a misnomer, they actually use a form of carbon called "graphite." The following link provides a nice overview and assorted references. http://science.howstuffworks.com/quest
Dorrie Grace:
My last post about "lead" got truncated, here is the full web address >> http://science.howstuffworks.com/question465.htm