Method for processing hydrocarbon pyrolysis effluent

By using a gas-liquid separator and rectifier system in a hydrocarbon pyrolysis unit to cool and separate steam cracking effluents, the problem of difficult cooling and tar removal of heavy feed effluents is solved, energy recovery efficiency is improved and equipment costs are reduced operational complexity and investment costs.

CN101218325AInactive Publication Date: 2008-07-09EXXONMOBIL CHEMICAL PATENTS INC
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2008-07-09
Estimated Expiration
Not applicable · inactive patent
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Abstract

A method and apparatus are disclosed for treating the effluent from a hydrocarbon pyrolysis unit employing a small primary fractionator, i.e., a rectifier. The method comprises cooling the gaseous effluent, e.g., by direct quench and / or at least one primary heat exchanger, and then cooling the gaseous effluent to a temperature at which tar, formed by reactions among constituents of the effluent, condenses, e.g., in a secondary exchanger. The resulting mixed gaseous and liquid effluent is passed through a rectifier, to cleanly separate quench oil from the gaseous effluent comprising a pyrolysis gasoline fraction, whose boiling point can be lowered as a result of the rectifier treatment. The effluent is then cooled to condense a liquid effluent comprising pyrolysis gasoline and water condensed from steam, which fractions are separated in a distillate drum. The cooled gaseous effluent is directed to a recovery train to recover light olefins. At least a portion of the pyrolysis gasoline-containing fraction can be recycled to the rectifier to enhance separation of the quench oil from the pyrolysis gasoline fraction.
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Description

[0001] Cross references to related applications

[0001] This application is hereby expressly incorporated by reference the entire disclosures of the following applications: Attorney Docket No. 2005B060, titled "Processing Method for Hydrocarbon Pyrolysis Emissions"; Attorney Docket No. 2005B061, titled "Hydrocarbon Pyrolysis Emissions" "Cooling method"; Agent file number 2005B062, titled "Processing method of hydrocarbon pyrolysis effluent"; Agent file number 2005B063, titled "Processing method of hydrocarbon pyrolysis effluent"; and Agent file number 2005B065, The title is "Processing Methods of Hydrocarbon Pyrolysis Emissions"; they are all incorporated herein by reference and filed at the same time as this application. Invention field

[0002] The present invention relates to a method for processing gaseous effluents from hydrocarbon pyrolysis plants, especially those plants that use feedstocks heavier than naphtha. Background of the invention

[0003] The preparation of light...

Examples

Embodiment Construction

[0049] The present invention provides a low-cost processing method for the gaseous effluent stream from a hydrocarbon pyrolysis reactor, thereby removing and recovering heat from the stream and separating C 5 + Hydrocarbons to provide separated pyrolysis gasoline and gas oil fractions (which may be suitable for use as quench oil), and the required C in the effluent 2 -C 4 Olefins without the need for a primary fractionator.

[0050] Generally, the effluent used in the process of the present invention is prepared by pyrolyzing a hydrocarbon feedstock (such as naphtha or gas oil) boiling in the temperature range of, say, about 40 to about 704°C (104-1300°F). For example, the effluent used in the process of the present invention is prepared by pyrolyzing hydrocarbon feedstocks (such as feedstocks heavier than naphtha) having a final boiling point greater than about 180°C (356°F). These raw materials include those that boil in the range of about 177 to about 538°C (350-1000°F), for ex...