纯MDI精馏塔生产MDI-50产品质量稳定性研究

Quality stability of MDI-50 produced by MDI refinery column

纯MDI精馏塔直接生产MDI-50产品保质期仅有3个月,提升其保质期到6个月有极大的经济效益。对MDI-50产品用色谱定性分析,确定浑浊物质组成为二聚体A,B,C等。通过对比实验确定MDI-50中二聚体A饱和溶解度最低,异构体质量分数在65%—70%时二聚体生成速率最低,采出温度越低二聚体生成速率越低,采出停留时间越长二聚体生成速率越快,MDI-50在25—35℃区间二聚体生成速率最低。总结出纯MDI精馏塔生产MDI-50产品采出温度、异构体质量分数、停留时间以及产品储存最佳温度等控制参数,按此参数生产的MDI-50产品保质期提升到6个月。影响MDI-50保质期的主要物质是二聚体,最优的解决方案是将MDI-50初始产品中二聚体质量分数降低至0.1%以下,可以进一步延长保质期到1年。

MDI-50 produced by MDI refinery column has 3 months quality guarantee period.Extending this guarantee period up to 6 months has great economic benefit.Turbid substance contains di-polymers of A,B,and C was confirmed by chromatography analysis.Comparative experiments show following:di-polymer A has the lowest solubility;di-polymers have lowest generation rate under 65%-70%isomer mass fraction;lower extraction temperature leads to lower di-polymers generation rate;longer residence duration leads to higher di-polymer generation rate;di-polymers have lowest generation rate when MDI-50 is stored under 25-35℃.Optimized parameters of extraction time,isomer concentration,residence duration,and storage temperature were summarized,and MDI-50 guarantee period was extended to 6 months by those optimized parameters.Di-polymers is the key factor affecting MDI-50 guarantee period.One year guarantee period can be achieved if the mass fraction of di-polymers is lower than 0.1%in the initial MDI-50 product.