Study On The Properties And Desulfurization Effect Of Pulping Black Liquor Slurry

In this study, air pollution caused by coal combustion in power plant, the main objective is to control the haze caused by coal fired flue gas. To study the effect of sulfur fixation, the black liquor from wood or straw pulping is added to the coal water slurry.Firstly, the slurry performance of black liquor coal slurry was studied, the results showed that adding different proportion in cotton pulp black liquor and straw black liquor CWS, the concentration and viscosity of coal water slurry decreased with the increase of the proportion of black liquor, and the flow performance and the stability is better, however, considering the heat value of coal water slurry combustion and its rheological properties and stability, the appropriate addition ratio of black liquor is at4%, then the cotton pulp black liquor coal slurry concentration is 64.12%, the viscosity is 857mPa·S, straw pulp black liquor coal slurry concentration is 63.16%,the viscosity is 776mPa·S. To detect the flow performance of coal water slurry, adding different kinds of additives to the black liquor coal water slurry, the study found that sodium lignin sulfonate has good dispersion performance, the Zeta potential of slurry is-50 mV, with high stability,study on the modification of sodium lignin sulfonate as the additive of coal water slurry.Secondly, the sodium lignin sulfonate was modified by graft copolymerization,the flow behavior of the modified product of coal water slurry additive was studied under different experimental conditions by single factor experiment, the optimal reaction conditions for the initiator system is FeSO4+H2O2, the monomer dosage is 1g,reaction time is 3.5H, the reaction temperature is 80, and the reaction pH value is 8, it can be seen through the SEM and FTIR analysis, the different groups of stretching vibration peaks appeared in the pure product, at this time, the grafting product was successful, the viscosity of coal water slurry decreased to 985mPa·s when the product was added to the coal water slurry.Finally, this paper studies the combustion performance and sulfur fixation of black liquor coal water slurry, Adding different proportion of cotton pulp black liquor of straw pulping black liquor in coal water slurry, the increase of the proportion of the pulping black liquor, the smaller ash content of the black liquor after combustion, but the proportion of black liquor should be moderate, in order to ensure that the calorific value of black liquor coal water slurry is moderate,when addition of black liquor ratio was 4%, cotton pulp black liquor CWS and black liquor CWS calorific value was18650 kJ*kg-1 and 17934 kJ*kg-1, the combustion performance of coal black liquor slurry is better and flash point advanced, two kinds of black liquor CWS flash temperature were 425℃and 435℃,The combustion process is more stable,And the black liquor CWS self desulfurization rate higher than ordinary water coal slurry, the rate is about12%~15%, the content of high melting point salts in ash is small. After adding desulfurization agent, the desulfurization rate of coal water slurry can be increased by 10%, but the viscosity of coal water slurry increased by 500~700mPa·s,and the stability was reduced to 4~6d, The addition of desulfurizing agent under 1% is appropriate.