Novel Technology for Removal of Sulfides From Condensate, 1999 Engineerging Conference Proceedings

A novel technology (patent pending) has been developed to treat contaminated condensate from black liquor evaporation plants. This is a new technology involving a closed loop concept that is comprised of three process steps:

1. Stripping of sulfides from condensate

2. Regenerative Thermal Oxidation (RTO) of Stripper Off Gases (SOG)

3. Absorption of sulfur dioxide and pH control of the condensate

By integrating these three process steps in a closed loop cycle, the cleaning of condensates can be done with a very high efficiency, good heat economy, and minimal impact on the environment. In order to reduce the total water consumption in the mill, the metal and sulfide free condensate can be recirculated into the bleach plant.

The main component in this cleaned condensate, methanol, does not consume any bleaching chemicals under normal conditions. Methanol is even proposed to act as a radical scavenger in many bleaching stages, reducing the reactions with carbohydrates.