Two stage contact cooler design for hot water generation (UOP)

CATEGORY: OLEFINS
PATENT
Two stage contact cooler design for hot water generation (UOP)
Publication date May 27, 2014
Also published as US20090326301
Inventors Adam Kanyuh
Original Assignee Uop Llc
Abstract
Systems and methods are provided herein for cooling an olefin cracking reactor effluent stream. One provided method includes reacting a hydrocarbon feedstock including C4+ olefins in an olefin cracking reactor to produce an olefin cracking reactor effluent stream, providing the olefin cracking reactor effluent stream to an inlet of a contact cooler, contacting the olefin cracking reactor effluent stream with a first quench liquid in a first contact zone in the contact cooler to produce a first bottoms stream and an intermediate vapor stream, contacting the intermediate vapor stream with a second quench liquid in a second contact zone in the contact cooler to produce a second bottoms stream and a cooled vapor stream, and removing the cooled vapor stream from an outlet of the contact cooler. The method can also include cooling the first bottoms stream to provide a cooled first bottoms stream, and cooling the second bottoms stream to provide a cooled second bottoms stream.
Description
TECHNICAL FIELD
This disclosure relates to the production of light olefins and, more particularly, to the production of light olefins via the cracking of heavier olefins.
DESCRIPTION OF RELATED ART
Light olefins are essential building blocks for the petrochemical and chemical industries, and can be use in the production of numerous important chemical products via polymerization, oligomerization, alkylation and other well-known chemical reactions. The term “light olefins” generally refers to C2 and C3 olefins, i.e., ethylene and propylene.
Olefin conversion technologies may be employed to produce light olefins from olefin containing feedstocks. Such olefin conversion processes can be combined or integrated with other olefin producing technologies such as, for example, steam or fluid catalytic cracking processes or oxygenate to olefin processes, to provide increased light olefin production.
There are two primary types of olefin conversion technologies for producing light olefins, metathesis and olefin cracking. Metathesis processes typically produce propylene by reacting ethylene with 2-butenes. Olefin cracking processes typically produce ethylene and propylene by cracking or converting feed streams containing C4+ olefins, such as, for example, C4-C8 olefin containing feedstocks, to produce effluent streams containing predominantly C2-C6 compounds along with some hydrogen and other lighter gases. Such effluent streams are subsequently separated into various product streams such as, for example, product streams containing ethylene and propylene.
Olefin cracking processes are generally conducted in a catalytic reactor at elevated temperatures, and typically produce effluent streams having temperatures in excess of 930° F. (500° C.). Typically, such olefin cracking reactor effluent streams are subsequently cooled and compressed to facilitate separation into individual product streams.
SUMMARY
This disclosure relates to systems and processes for cooling an olefin cracking reactor effluent stream.
In one aspect, a process for cooling an olefin cracking reactor effluent stream is provided that includes reacting a hydrocarbon feedstock including C4+ olefins in an olefin cracking reactor to produce an olefin cracking reactor effluent stream and providing the olefin cracking reactor effluent stream to an inlet of a contact cooler. In the contact cooler, the olefin cracking reactor effluent stream is contacted with a first quench liquid in a first contact zone to produce a first bottoms stream and an intermediate vapor stream. The intermediate vapor stream is contacted with a second quench liquid in a second contact zone in the contact cooler to produce a second bottoms stream and a cooled vapor stream. The first quench liquid and second quench liquid can each be a quench oil. The cooled vapor stream is removed from an outlet of the contact cooler. Preferably, the intermediate vapor stream is passed through an accumulator tray prior to contacting the intermediate vapor stream with the second quench liquid in a second contact zone. The cooled vapor stream can also be through a mesh blanket before being removed from the contact cooler. Additionally, the first bottoms stream is cooled to provide a cooled first bottoms stream, and the second bottoms stream is cooled to provide a cooled second bottoms stream. A first exchanger and a second heat exchanger can be used for the cooling of the first bottoms stream and the second bottoms stream, respectively. At least a portion of the cooled first bottoms stream can be returned to the contact cooler as at least a portion of the first quench liquid. Similarly, at least a portion of the cooled second bottoms stream can be returned to the contact cooler as at least a portion of the second quench liquid.
In another aspect, a system for cooling an olefin cracking reactor effluent stream is provided that includes an olefin cracking reactor, a contact cooler, a first heat exchanger, and a second heat exchanger. The olefin cracking reactor receives a hydrocarbon feedstock including C4 to C8 olefins and produces an olefin cracking reactor effluent stream. The contact cooler has an inlet that receives the olefin cracking reactor effluent stream. The contact cooler also includes a first contact zone where the olefin cracking reactor effluent stream contacts a first quench liquid to produce an intermediate vapor stream and a first bottoms stream, an accumulator tray, a second contact zone where the intermediate vapor stream contacts a second quench liquid to produce a cooled vapor stream and a second bottoms stream, and an outlet through which the cooled vapor stream is removed from the contact cooler. The first heat exchanger that removes heat from the first bottoms stream by indirect heat exchange with a first cooling liquid. The second heat exchanger that removes heat from the second bottoms stream by indirect heat exchange with a second cooling liquid.
Free Full Text Source: http://www.google.com/patents/US8735642