Turning waste cardboard into fuel

CSIRO has developed an innovative solution to two very different problems confronting two industries in the remote community of King Island in the Bass Strait - by transforming waste cardboard into an abundant fuel source.

Finding alternative fuel sources on a small remote island was a big problem for industrial seaweed processor Kelp Industries. The company dries seaweed and exports extracts to be used as thickening agents in food and industrial products worldwide.

Faced with a future shortage of wood, a rising cost of shipping in liquified petroleum gas (LPG) and the importance of the island's environmental reputation, Kelp Industries found an ally in the famous King Island Dairy (owned by National Foods).

Kelp Industries general manager John Hiscock says: "We had a fuel problem and they had a cardboard problem. The dairy had mentioned how much waste cardboard they had that was too expensive to ship back to the mainland, and were wondering how else they could use it on the island. "Then I remembered the briquettes made from cardboard I'd seen for sale in a shop somewhere."

The result was an idea to recycle King Island's excess cardboard packaging - about three 400 L bins a week - into dense briquettes to help fuel the kelp furnaces and drying kilns.

As an expert in furnaces and coal briquetting, CSIRO Minerals principal research scientist Bob Flann was called to check if the idea was scientifically practical.

"It was a project from left field with a natty solution, and I really liked the idea that CSIRO could assist the island people in facilitating a good outcome," Mr Flann says.

Key scientific elements that CSIRO needed to resolve were the correct density of the cardboard briquettes for use in the furnace, the optimal ratio of cardboard to wood burning to sustain the process, and ash analysis to ensure impurities from the cardboard did not contaminate the drying seaweed.

Mr Flann's team found that solid briquettes - the size of a house brick - made from shredded cardboard waste work well in the furnace as a 30 to 50% component of the total fuel mix.

"It's been a really satisfying project, both technically and in being able to help the community so practically and in two such important ways," Mr Flann says.

"There are still financial aspects of the project to be resolved, but it has been a great example of how applied technology developed in the coal industry can assist a remote community."