Monoethylene glycol reclamation based on chemical precipitation process

The key step in reclamation of monoethylene glycol (MEG) is chloride removal from the rich MEG solution containing high Cl concentration. Chloride removal from MEG reclamation operation has been investigated in this wok through the chemical precipitation of insoluble Friedel's salt, created by the addition of calcium and aluminum compounds. Response surface methodology has been used to design experiments and optimize the effect of independent variables. The selected ranges of various factors were: initial concentration of chloride (1500-4500 mg/l), molar ratio of Al: Cl (0.5-3), molar ratio of Ca: Cl (1-6), Temperature (25-80 degrees C), and wt.% of MEG (30-70). It was found that at higher starting Cl concentrations, the reaction for forming Friedel's salt is superior to other reactions. The efficiency of multi-stage Cl removal has also been investigated. It was found that, under assumed operating conditions, a 70% removal efficiency at each step and a 97% chloride removal can be achieved by the end of stage 3.

Automated summary

In this study, chloride removal from rich MEG solution was achieved through the chemical precipitation of insoluble Friedel's salt. Response surface methodology was used to optimize independent variables, showing that the reaction for forming Friedel's salt is most effective at higher starting Cl concentrations. Multi-stage Cl removal efficiency was investigated, concluding that a 97% chloride removal can be achieved by the end of stage 3 with 70% removal efficiency at each step.