Method and apparatus for reducing decomposition byproducts in a methanol to olefin reactor system

Abstract

Disclosed is a method and apparatus for reducing the amount of metal catalyzed side-reaction byproducts formed in the feed vaporization and introduction system of a methanol to olefin reactor system by monitoring and / or maintaining the temperature of at least a portion of the feed vaporization and introduction system and / or of the feedstock contained therein below about 400° C., 350° C., 300° C., 250° C., 200° C. or below about 150° C. The temperature can be maintained in the desired range by jacketing at least a portion of the feed vaporization and introduction system, such as at least a portion of the feed introduction nozzle, with a thermally insulating material or by implementing a cooling system.

Description

FIELD OF THE INVENTION [0001] This invention is to an apparatus and method for reducing methanol decomposition byproducts in a methanol to olefin reactor system. BACKGROUND OF THE INVENTION [0002] Light olefins, defined herein as ethylene and propylene, serve as feeds for the production of numerous important chemicals and polymers. Light olefins traditionally are produced by cracking petroleum feeds. Because of the limited supply and escalating cost of petroleum feeds, the cost of producing olefins from petroleum sources has increased steadily. Efforts to develop and improve olefin production technologies, particularly light olefins production technologies, have increased. [0003] The petrochemical industry has known for some time that oxygenates, especially alcohols, are convertible into light olefin(s). There are numerous technologies available for producing oxygenates including fermentation or reaction of synthesis gas derived from natural gas, petroleum liquids, carbonaceous mate...

AI Technical Summary

Benefits of technology

"The present invention provides a method for making light olefins from oxygenate-containing feedstocks with reduced production of metal catalyzed side reaction byproducts. This is achieved by maintaining the inner surface of the nozzle through which the feedstock passes at a temperature below about 400°C, 350°C, or 300°C, and by using a thermally insulating material to cover at least a portion of the nozzle. The resulting light olefins stream contains less metal catalyzed side reaction byproducts, reducing olefin separation and purification costs. The invention also includes a method for making an olefin product from an oxygenate-containing feedstock by heating the feedstock and directing it through a feed nozzle into an MTO reactor while maintaining the nozzle at a temperature below about 400°C. The nozzle is optionally covered with a thermally insulating material."

Problems solved by technology

Because of the limited supply and escalating cost of petroleum feeds, the cost of producing olefins from petroleum sources has increased steadily.

In a typical MTO reactor system, undesirable byproducts may be formed through side reactions.

If the methanol contacts the metal reactor wall at sufficient temperature and pressure, the methanol may be converted to undesirable methane and / or other byproducts.

Byproduct formation in an MTO reactor is undesirable for several reasons.

First, increased investment is required to separate and recover the byproducts from the desired light olefins.

In other words, the production of byproducts is undesirable because methanol feed is consumed to produce the byproducts.

Further, although the relative concentrations of metal catalyzed side reaction byproducts are generally quite low, the total amount of byproducts produced on an industrial scale can be enormous.

Although passivating chemicals have proven effective in reducing metal catalyzed side reactions, the introduction of deactivating or passivating chemicals increases production costs because these chemicals or their products must be separated from the desired product.

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