Is the recovery boiler steam production affected by borate autocausticizing?
The effect of borate autocausticizing on the recovery boiler steam production is small at low autocausticizing levels. Although autocausticizing increases the inorganic solids load in the liquor cycle, it does not affect the total heat input to the boiler (per ton of pulp); therefore, the effect on steam production is small. Principally some decrease in steam production is expected mainly due to the heat loss associated with the higher smelt flow, the endothermic AC reaction, and the higher water evaporation load. These extra heat losses are partly compensated by a decrease in the recycled dust load, and may also be affected by changes in digester operations such as the level of alkali charge and pulp yield. In most AC applications, no decrease in the boiler steam production is observed at autocausticizing levels of up to about 10%.
