Abstract: The invention disclosed here is a process or system for treating the effluent from a BCTMP pulp mill. The effluent is evaporated to produce a water condensate and a remaining waste product concentrate. The condensate is recycled for use in the BCTMP mill, or is dumped into the environment. The concentrate is incinerated in a recovery boiler. Incineration results in the recovery of certain reusable chemicals. At least some of such chemicals are fed back into the effluent while it is being evaporated, to buffer it, and thereby prevent the carryover of undesirable organic acids into the condensate. This ensures sufficient condensate purity for recycling it in the BCTMP process, or for otherwise dumping it into the environment.

Abstract: Recovery boiler wind boxes are upgraded by providing an air nozzle and damper installation where the nozzle crosses through the inside of the wind box. Air is channeled from the box into the nozzle by the damper. The nozzle is convergent and jets air into the boiler's combustion chamber. The typical boiler has a plurality of combustion air ports leading into the chamber. Modifying each air port by using the nozzle and damper installation creates a surrounding arrangement of air jets about the chamber which creates turbulent mixing in the boiler's furnace gases.