By: E&P Staff
The Ecocool/T dryer, the latest model from Goss International, features a new integrated afterburner and pollution-control system that increases heat-exchange efficiency and reduces energy consumption — for both drying and afterburning — up to 40%.
The latest Ecocool technology maximizes use of evaporated ink solvents, according to Goss Product Manager Rob Bosman. “Instead of releasing solvent-laden exhaust air to a separate pollution-control device, we are burning it and using the energy to fuel the dryer in a closed-loop system,” Bosman said in a statement.
Afterburning is not new, but Bosman attributed increased heat-exchange efficieny to Goss advanced technology, which reduces the amount of gas needed solvent fumes emitted. Solvent hydrocarbons are reduced to carbon dioxide and water. “The air that is eventually emitted to the atmosphere is about 99.9% clean,” said Bosman.
As the printed web enters the Ecocool dryer, burners typically heat it to 284 ?F, driving solvents out of the ink and extracting them along with the air just before the dryer’s cooling section. In the upper and lower burner units, solvent-laden air passes through a heat exchanger, which typically heats it to 1,020 ?F, creating combustion energy.
The air then passes into the primary burner chamber where it is heated to even higher temperatures of approximately 1454?F. By the time the air reaches the end of the first burner chamber, the solvents have been incinerated. Up to 40% of this clean air is channeled back into the dryer through a hot-air valve that automatically opens or closes, depending on the energy needed to dry a web. The rest flows through the secondary burner chamber and is expelled through the dryer exhaust outlet as carbon dioxide.
Ecocool’s integrated chill rolls (which improve print quality by preventing solvent condensate from developing between chill rolls and the cooling web) also have a positive environmental impact. Free of condensate, the rolls need no cleaning, eliminating associated VOC cleaner waste and operator exposure. And their immediate proximity allows any remaining ink solvents released in the chill section to be drawn back into the dryer.
The chill stand can be equipped with an infrared camera to measure web temperature after the chill section and to vary the chill power as needed, helping reduce the energy used for cooling. In contrast, conventional systems’ fixed chill power can unnecessarily over-cool light stock.