Abstract: A substantial and increasing problem with the pulping chemical recovery system, is the presence of chloride and potassium in the spent liquor entering the recovery boiler. Chloride and potassium increase the stickiness of carryover deposits and dust particles to the recovery boiler tubes, which accelerate fouling and plugging in the upper part of the recovery boiler. The present invention relates to a process by which the content of potassium ions in a recovery system for pulping chemicals can be reduced. The process comprises bringing spent liquor to a recovery boiler, burning said spent liquor, collecting precipitator dust formed, forming a solution by dissolving the precipitator dust in a liquid, where the solution of precipitator dust is subjected to a treatment with an inorganic ion exchange material in order to remove at least a part of the potassium therein.

Abstract: The invention relates to a method for producing peracetic acid by reacting hydrogen peroxide and acetic acid in a water-based reaction medium in a reactor and continuously distilling off the produced peracetic acid. Thermal energy in an in an amount exceeding about 0.2 kW/kg reaction medium.

Abstract: A cracking catalyst having good resistance to metal poisoning has at least two particle fractions of different particle sizes, the cracking catalyzing zeolite material being concentrated to the coarser particle size fractions, and the finer particle size fractions being formed from material having relatively lower or no or insignificant cracking catalyzing activity. The particles of the finer particle size fractions have a matrix of kaolin and amorphous alumina-silica and may contain for example, an SO.sub.x eliminating additive such as Al.sub.2 O.sub.3, CaO and/or MgO. The coarser particle size fractions having cracking catalyzing effect have a mean particle size of from 80 to 125 .mu.m and the finer particle size fractions a mean particle size of from 30 to 75 .mu.m.