Making Dense Briquettes from Fine Dust

Background:

The General Electric Lighting Division produces a variety of lighting products. At its glass plant, GE produces borosilicate glass for over a hundred different lens covers and reflectors.

During glass production, each day more than 650 bounds of mostly borax and salt dust are collected. GE uses the recovered dust as a minor ingredient in making new glass, but working with the dust is difficult.

Challenge:

GE initially used a pelletizing process to prepare the dust for recycling. But after each batch run, the equipment had to be washed to prevent salty residue from corroding the pelletizer during idle periods – which was fairly labor intensive according to Henry Dietzel, Manager of Furnace and Facilities at GE’s Somerset plant.

Plus, the process introduced water into the dry material handling system, which meant the pellets had to be dried before they could join the production cycle.

Solution:

After seeing briquetters in action at a nearby Kingsford charcoal plant, GE saw the potential for briquetters in their own operation. They sent captured flue dust to K.R. KOMAREK Inc.’s research lab for a test, which showed that the dust could be pressed into small briquettes without water or another binder.

Dietzel says that the positive test results at the research lab convinced them to move forward. “We knew KOMAREK was a leader in the briquetting equipment field and we decided that was the direction we wanted to head.”

General Electric installed a KOMAREK low-speed roll-press briquetter, which forms chalk-shaped sticks through the use of two vertically opposed, counter-rotating rolls. A screw feeder in the briquetter’s inlet feed hopper delivers dust into the rolls’ nip region, where the rolls come together. As the rolls turn, the upper and lower pockets join to form each briquette-shaped cavity. Pressure applied to the dust as the pockets close creates the stick-shaped briquette.

Adjustments were made to accommodate differences between hot dust and dust that had cooled. KOMAREK made new rolls that included two rows of pockets in a staggered pattern and that were about half the original briquette size. This allowed the rolls to produce briquettes at various roll speeds, which in turn matches the briquetting process with the captured dust volume.

Results:

Since installing the briquetter, Dietzel said operators have spent less time attending to the dust handling equipment. “It has reduced the number of work-hours that we put in to recycle dust…and it has eliminated the environmental concerns we had when cleaning the pelletizer with water.”

According to Dietzel, “the briquetter has met all of GE’s expectations.”