Corrugated paper manufacturers find better uses for black liquor by-product

Two companies have announced that they will commercialize the world’s first low-temperature black liquor gasification system.
Black liquor is the liquid created during the manufacture of corrugated paper. The liquor was traditionally stored in ponds or applied to gravel roads to suppress dust. However, after Canada outlawed its use as a dust suppressant, manufacturers had to find alternative uses for the by-product.
The solution developed by Norampac and ThermoChem Recovery International is to separate the black liquor into inorganic and organic components. The inorganic sodium bicarbonate is recycled and returned to the pulp mill. The organic material is turned into a synthesis gas of carbon monoxide and hydrogen. This gas is in turn converted to steam to help power the plant.
The process was put through a performance test in a mill in Trenton, Ontario and passed performance tests in April 2005 and air emissions tests in October 2006.
J.J. Davis, general manager of the Trenton mill, says they chose the black liquor process based on cost effectiveness and environmental benefits. However, there are still some challenges to overcome. Davis says they are still looking to boost the energy production. Also some of the equipment is still in the Prototype State and has to be re-engineered.
The Trenton plant produces about 80,000 tonnes of corrugated paper from virgin and recycled fibres.
Source: Heads Up CIPEC newsletter from the Office of Energy Efficiency, Natural Resources Canada.