How does borate affect the recovery boiler superheater fouling?
The superheater fouling is related to either the high quantity or the melting temperatures of carryover particles. With proper control of boiler operating conditions, no effect is expected on the carryover quantity. However, the carryover melting behavior may be affected because borates are expected to be present in carryover. The melting behavior of carryover can be affected by many factors including the borate content of the liquor. Normally, at low autocausticizing levels and at medium or high Cl content in the liquor, no effect is expected from borate. At Cl contents lower than 0.5 wt% in black liquor and higher AC levels, a shift in the sticky temperature zone in the superheater could occur. Recognizing this potential and monitoring the boiler operation is the key in controlling the superheater fouling during an autocausticizing applications. A number of successful applications of autocausticizing encountered initial impacts on superheater fouling, but managed to control it by pro
