关键词: 甲醇制烯烃, 废水处理, 微通道分离, 旋流再生, 化学需氧量

Abstract:

In the methanol to olefins (MTO) process, the defects of the original design leads aromatic hydrocarbons and heavy components in the process water cannot to be proposed by steam, resulting in a certain amount of suspended and colloidal pollutants in the purified water at the bottom of the sewage stripper. The high content of chemical oxygen demand (COD) has become an obstacle to the reuse of wastewater. In view of the shortcomings of the current MTO wastewater treatment technology, this paper proposed a new type of cyclone regeneration microchannel separator series process based on field experiments, which was used to classify and treat MTO purified water. The primary separator was used to remove non-dissolved pollutants in purified water and reduce some COD content, and the secondary separator was used to deeply remove COD. The first-stage adsorbent MC-1 and the second-stage adsorbent MC-4 had the best adsorption efficiency, and the cross-sectional flow rate of the bed was most suitable to be controlled at 2.5mm/s. The average turbidity of the purified water after treatment was reduced from 18.3NTU to 2NTU, the suspended solids content was reduced from 18mg/L to 2.79mg/L, the separation efficiency was basically higher than 80%, and the chemical oxygen demand COD content was reduced by 318mg/L on average. The separation and purification effect was obvious. The purified water after treatment can replace the turbine condensate for olefin separation water washing tower or reuse to other water units. The process had the characteristics of low cost, high removal efficiency of suspended particles, colloidal particles and small molecular organic matter, and complete regeneration of separation media. It effectively solved the problem of difficult reuse of wastewater in the process of methanol to olefins (MTO). It was of great significance to reduce environmental pollution and save water resources.

Key words: methanol to olefins, wastewater treatment, microchannel separation, swirl regeneration, chemical oxygen demand (COD)