气化灰水pH与氯离子波动原因及控制措施OA

To address the risks of equipment corrosion,scaling,and non-compliance with environmental standards caused by fluctuations in ash water pH(deviating from the control index of 7.0～9.0)and chloride ion concentration(exceeding the limit of 500 mg/L)in coal-water slurry gasification units in severe cold areas,a multi-nozzle opposed coal-water slurry gasification unit of a local enterprise was selected as the research object.The core factors causing the fluctuations were identified through on-site data monitoring,process parameter tracing,and raw material characteristic analysis,and corresponding control measures were formulated.The results indicated that pH fluctuation was attributed to changes in the quality of urea wastewater,adjustments in the blending ratio of high-alkali metal Q coal,excessive dosage of coal slurry additives,and fluctuations in water quality during the pulping process.Chloride ion fluctuation was caused by the addition of calcium chloride antifreeze in winter,changes in the blending ratio of raw coal,and analytical deviations of the chloride ion titrator.After the implementation of the proposed control measures,the pH value of ash water was stably controlled within 8.5～8.9,and the chloride ion concentration was effectively controlled below 400 mg/L,which not only eliminated the problems of equipment corrosion and scaling but also ensured compliance with environmental protection standards for both normal and potential ash water discharge scenarios.The proposed control measures can provide a reference for ash water treatment and environmental compliance of similar gasification units in severe cold areas.