It's said that one man's trash can be another man's treasure. And for our paper mills, sometimes one machine's waste can become a treasure when it's reused.
The team at our Cedar Springs, Georgia, mill recently completed a project that turns what used to be waste into real cost savings. The Waste Heat Recovery Project was designed to capture the heat in condensate, a byproduct of the black liquor evaporation process. (Black liquor is an industry term for the material that's left over from the pulp washing process.)
This hot material, before being disposed of, now transfers its heat to de‐mineralized (or boiler feed) water, resulting in a significant stream of savings per year. How's that for turning trash into treasure?
Process Engineer Ramsey Phillips explained how the new setup equates to savings. “It takes fuel to make steam. So if we don't make as much steam, we don't use as much fuel. If we don't use as much fuel, we save money.” The project, which took about six months to complete once construction began, is an example of reducing waste and increasing the efficiency of the manufacturing process.
“What we're here to do is to make the best out of what we've got. We are always looking at ways to operate our equipment and processes more efficiently and to capture the most energy that we can,” said Phillips.
Did you know? Black liquor is the material that's left over from the pulp washing process. It's burned for fuel in the recovery boiler. But before that happens, its moisture level needs to be reduced. Coming out of the washer, black liquor is less than 20 percent solids. It's put through the evaporation process to increase the solids to around 75 percent, so that it can be burned.