Chloride enters the mill in wood chips, caustic, and generator spent acid and can cause corrosion and plugging of the recovery boiler, leading to minimized steam generation and costly shutdowns. The PDP Precipitator Dust Purification System is a chloride removal system that selectively removes chloride from electrostatic precipitator (ESP) dust in a Kraft mill. Based on the SSU™ system, the highly selective ion exchange resin separates chloride from sulfate salts while also recovering valuable cooking chemicals.
A large portion of potassium salts can be found in ESP ash and can build up and cause corrosion and other process upsets. The PRU system controls potassium levels in a Kraft mill by selectively removing potassium from the ash solution via ion exchange under specific operating conditions. This method offers a more cost-effective solution compared to purging excess ash to control potassium levels. The PRU system also helps recover valuable cooking chemicals and reduces the need for costly shutdowns due to boiler corrosion and plugging.
Based on the APU® system, the GAP system operates on chlorine dioxide generators in Kraft mills. During chlorine dioxide generation, sodium sulfates are also produced and can accumulate to cause problems. The GAP system separates the sulfuric acid solution containing chlorine dioxide from the sodium sulfate, allowing for reduced caustic and sulfuric acid purchases, fewer shutdowns, and low salt loss.