基于粒度分布的MRU脱盐闪蒸罐工艺参数优选

Optimization of parameters for MRU desalination flash drum process based on particle size distribution

乙二醇再生脱盐装置是深水天然气开发中的核心装置之一,常采用蒸发结晶和重力沉降原理来实现高溶解度盐(如NaCl)的脱除。对脱盐闪蒸罐的主要工艺参数,过去主要从能耗的角度进行优选,只能反映工艺参数对蒸发的影响,难以直接反映对结晶与颗粒沉降分离的影响。从晶体粒度分布的角度出发,利用激光粒度仪研究了温度、压力和停留时间等因素对NaCl在乙二醇溶液中晶体粒度分布的影响规律,并据此优选工艺参数。结果表明,在同等条件下,温度越高,晶体的粒度分布越分散,平均粒度越小;真空度越高,晶体的粒度分布越分散,平均粒度越小;停留时间过长或过短都将导致晶体的平均粒度变小。对所讨论的介质,优选后的工艺参数为:闪蒸温度140℃,压力-80kPa,停留时间5min。经研制的连续实验装置验证,优选后的参数能实现稳定的沉降分离和脱盐。

Monoethylene glycol regeneration ga desalination system is one of key units in deepwater gas development, often using evaporative crystallization and sedimentation theory to achieve high solubility salt （such as NaCI） removal. The main process parameters on the desalting flash tank, mainly optimized from the perspective of energy in the past, can only show the effects of process parameters on evaporation, but not directly show the effects on the crystallization and particles settling ~ separation. To study the main process parameters of flash separator as a crystallizer, the influence of temperature, pressure, and residence time on the crystal size distribution of NaC1 in ethylene glycol solution was studied by laser diffraction particle size analyzer. The results showed that under the same conditions, the higher temperature, the more dispersive crystal size distribution and the smaller average particle size; the higher degree of vacuum, the more dispersive crystal size distribution and the smaller average particle size; too long or too short of residence time would cause the average crystal size to become small. For discussed solutions, optimized process parameters are that flash temperature is 140℃, pressure is --80 kPa, and the residence time is 5 minutes. The optimized parameters can achieve stable sedimentation separation and desalination by the verification of developed continuous experimental apparatus.