Clean combustion is a major challenge for mill operators.
Power and recovery boilers produce steam and energy by reducing black liquor to a molten smelt in order to reclaim spent chemicals in the pulping process. The power boiler typically burns hog fuel to produce steam that can be used to heat the process or generate electricity in a turbine driven generator. The power produced can be used in the mill or exported to the electricity grid. Working with chemicals with a high percentage of solids, high steam pressures and temperatures, large pressure drops, as well as meeting environmental regulations for clean combustion are challenges for mill operators.