摘要
煤气化过程中产生的NH3和CO2,在煤气洗涤、灰水处理、变换和热回收工段与水形成NH3-CO2-H2O三元体系,通过三元体系相平衡的热力学模型,能够预测NH3在系统中的分布,解决煤气化装置普遍存在的铵盐结晶、废水氨氮超标等问题。提出了NH3和CO2在水中的解离反应和酸碱反应,是造成Aspen中NH3-CO2-H2O三元体系电解质NRTL模型与实验数据产生偏差的原因。利用系统压力0—1.2 MPa条件下NH3-CO2-H2O三元体系的气液平衡实验数据,回归了NH3-CO2-H2O三元体系电解质NRTL模型的二元交互作用参数和亨利系数,得到修正的NH3-CO2-H2O三元体系电解质NRTL模型。模型计算结果与实验数据间的平均相对误差小于2.9%,能够准确地预测煤气化装置中低压含NH3系统的气液相平衡,对工程设计和装置运行具有一定指导意义。
Coal gasification process produces NH3 and CO2,which forms NH3-CO2-H2 O ternary system with water in the gas washing,gray water treatment,shift and heat recovery section. An accurate ternary system phase equilibrium model can predict NH3 distribution in gasification and solve the problem of crystallization of ammonium salt and excessive ammonia in waste water. It is proposed that the ionization and acid-based reactions between NH3 and CO2in aqueous solution cause the bias of experimental data and Aspen electrolyte NRTL model predicted value. The binary interaction parameters of electrolyte NRTL model and Henry＇s coefficient were regressed by using vapor-liquid equilibrium experimental data of NH3-CO2-H2 O ternary system. The modified electrolyte NRTL model was established. The average relative error between modified model calculated result and experimental data is less than 2. 9%. The modified model can accurately predict NH3-CO2-H2 O ternary system vapor-liquid equilibrium of coal gasification equipment operated in low pressure,which has great importance in engineering design and plant operation.
出处
《化学工程》
CAS
CSCD
北大核心
2014年第11期61-65,共5页
Chemical Engineering(China)
