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Selective hydrogenation method of acetylene hydrocarbon and dialkene in cracking gas

A technology for selective hydrogenation and diolefins, applied in the field of selective hydrogenation of alkynes and diolefins, which can solve the problems of limited hydrogen, increased energy consumption, and reduced activity of polymerization catalysts, so as to reduce energy consumption and equipment size, and improve selection Safety and safety, and the effect of reducing the number of reaction devices

Active Publication Date: 2009-06-10
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The shortcoming of this patent is: 1, because this patent application places the mixed-phase hydrogenation reactor on the downstream side of the front depropanizer, what enters the mixed-phase hydrogenation reactor is cooled and partially condensed rich in C 3 and lighter component streams, so this patented technology can only hydrogenate low-carbon alkynes in the mixed-phase hydrogenation reactor, and cannot hydrogenate high-carbon alkynes such as butyne and butadiene, so The amount of hydrogen consumed is limited, and a large amount of remaining hydrogen enters the cryogenic part of the cracked gas, resulting in high energy consumption
2. If the remaining high-carbon alkynes and dienes enter the polymerization process, the activity of the polymerization catalyst will be reduced, and the physical properties of the polymer will be deteriorated
3. Since the patent application does not carry out hydrotreating on the stream entering the front depropanizer, the alkynes and diolefins in the stream are likely to cause coking in the tower and increase energy consumption
4. Due to the use of this patent application technology, a series of additional equipment is required to separate the C 3 and C 3 The above components are additionally treated to remove alkynes and diolefins, thereby increasing equipment investment and production energy consumption as a whole
In the mixed-phase hydrogenation reactor, the carbon three components are in the gas phase, and the carbon four and carbon five components are mostly in the gas phase. They cannot fully play the role of flushing the catalyst bed, and at the same time they repeatedly enter the front depropanizer or the front B. Depropanizer, which undoubtedly increases the energy consumption, equipment size and operating cost of the pre-depropanizer or pre-ethanizer
In the case of using the front ethane column, the liquid phase stream recycled back to the mixed-phase hydrogenation reactor contains propylene, which is very detrimental to the selectivity of the mixed-phase hydrogenation, resulting in loss of propylene

Method used

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  • Selective hydrogenation method of acetylene hydrocarbon and dialkene in cracking gas

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Embodiment approach

[0054] As a more specific embodiment of the present invention, comprising the following steps:

[0055] a. Cool the feedstock containing olefins to 10°C to 90°C through a heat exchanger;

[0056] b. Sending the material from step a into the mixed-phase hydrogenation reactor 1, at least partially hydrogenating the highly unsaturated hydrocarbons therein;

[0057] c. the effluent from the mixed-phase hydrogenation reactor 1 is cooled by a cooler, and the cooled stream is sent to the condensing fractionator 2, and is separated into an uncondensed stream and a condensed stream comprising carbon six and heavier components, and A part of the condensate stream rich in C6 and heavier components is sent to the mixed-phase hydrogenation reactor 1, and the remaining part is withdrawn;

[0058] d. Include the C 5 And the stream of lighter components is sent to the front depropanizer 3, separated into C-rich 3 and gas phase streams of lighter components and containing C 4 And the liqui...

Embodiment 1

[0062] see figure 1 , the gas-phase raw material containing olefins obtained from the steam cracking unit is mixed with the condensate stream from the fractionator, then heat exchanged in the heat exchanger, and then enters the mixed-phase hydrogenation reactor 1. Mixed-phase hydrogenation reactor 1 uses BC-L-83A hydrogenation catalyst (Sinopec Produced by the company's Beijing Research Institute of Chemical Industry) to operate in the presence of, for example, the reaction temperature is 60 ° C, the reaction pressure is 2.0 MPa, and the volume space velocity of the gas phase raw material is 1100 h -1 , the volumetric space velocity of the liquid stream is 3h -1, the acetylene in it can be hydrogenated to 100-200ppm, the conversion rate of propyne and propadiene is 50%, and the conversion rate of dienes with carbon four or more is more than 80%. The reaction product from the mixed-phase hydrogenation reactor is cooled by a cooler and enters the condensing fractionator 2, whe...

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Abstract

The invention discloses a selective hydrogenation method for acetylene hydrocarbon and diene in pyrolysis gas and belongs to the technical field of selective hydrogenation of unsaturated hydrocarbon. In order to solve the problems in the prior art of high energy consumption, large equipment size, high operation cost, incapable of improvement of C3 selectivity, and the like, due to the facts that liquid phase flow of a mixed phase hydrogenation reactor contains a large amount of C3, C4 and C5 components, can not realize full rinse in the reactor, and repeatedly enters into a front depropanizing tower. The invention provides the method which comprises: carrying out preferential selective hydrogenation of C2-C10 highly unsaturated hydrocarbon (acetylene hydrocarbon and diene) on the upstream of the front depropanizing tower; condensing heavy components above C6 through dephlegmation; and using the heavy components as the fluid phase flow of the mixed phase hydrogenation reactor. The method makes full use of the liquid phase flow of the mixed phase hydrogenation reactor, reduces feeding quantity of the front depropanizing tower, energy consumption and equipment investment, and is propitious to improve selectivity.

Description

technical field [0001] The present invention relates to a method for the selective hydrogenation of alkynes and dienes, more specifically, the invention relates to a method for the selective hydrogenation of alkynes and dienes in the cracked product stream of an olefin production unit. Background technique [0002] Unless otherwise specified, the highly unsaturated hydrocarbons mentioned in the present invention refer to hydrocarbons containing triple bonds or two double bonds. [0003] Processes for the conversion of hydrocarbons at high temperatures, such as steam thermal cracking or catalytic cracking, can provide unsaturated hydrocarbons, such as ethylene, acetylene, propylene, butadiene, butene; saturated alkanes, such as ethane, propane, butane; There are also light components such as methane, hydrogen and carbon monoxide and hydrocarbons with a boiling point in the gasoline range. The gas-phase monoolefins with more than two carbon atoms obtained by these processes a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C10G45/32C07C5/02
Inventor 田保亮戴伟彭晖穆玮乐毅唐国旗张齐鲁耘
Owner CHINA PETROLEUM & CHEM CORP
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