Options to reduce fouling in MTO downstream recovery

摘要

A process is presented for removing the fouling problems associated with the product recovery in a methanol to olefins conversion process. The process includes passing the quenched MTO process stream to a product separator, wherein an intermediate stream is generated and includes water and heavier hydrocarbons. The intermediate stream is processed to remove the buildup of heavier hydrocarbons.

主权项

1. A process for reducing fouling in an MTO process, comprising:
passing a product effluent stream comprising olefins, solid materials, and highly substituted aromatic hydrocarbons including hexamethylbenzene and pentamethyl benzene from an MTO reactor to a quench tower to generate a first overhead stream comprising olefins and said highly substituted aromatics, and a first bottoms stream comprising waste water; passing the first overhead stream to a product separator unit to generate a second overhead stream comprising olefins and water, a second bottoms stream comprising waste water, and an intermediate stream comprising water and highly substituted aromatic hydrocarbons; passing the second overhead stream to a product treatment and recovery system to separate the second overhead stream, in compression and separation steps, into a hydrocarbon stream and a water stream and a light hydrocarbon stream comprising olefins; passing the water stream from the product treatment and recovery system to an oxygenate stripper; cooling a portion of the intermediate stream and passing a portion of the cooled portion of the intermediate stream as reflux to the top of the product separator unit and the remainder to a water stripper to generate a water overhead stream for use in the product separator unit and a water bottom stream for passing to a water treatment unit; passing another portion of the intermediate stream to a second separation unit to generate a hydrocarbon stream containing highly substituted aromatic hydrocarbons a second bottoms stream comprising waste water; passing the first bottoms stream comprising waste water, second bottoms stream comprising waste water, and second bottoms stream comprising waste water to the water stripper; passing the hydrocarbon stream and the stream containing highly substituted aromatic hydrocarbons to wash column to generate and a washed hydrocarbon stream comprising C4 and higher hydrocarbons and a wash stream comprising methanol and water; and passing the washed hydrocarbon stream to an olefin cracking process.