Methods for alkylene oxide separation using extractive destillation columns

一种萃取蒸馏塔、蒸馏塔的技术,应用在纯化和回收氧化丙烯领域,能够解决改进不实用等问题

Active Publication Date: 2014-02-05
LYONDELL CHEM TECH LP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

These teachings are not practical for retrofitting existing equipment

Method used

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  • Methods for alkylene oxide separation using extractive destillation columns
  • Methods for alkylene oxide separation using extractive destillation columns
  • Methods for alkylene oxide separation using extractive destillation columns

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] Example 1 is described in e.g. figure 1 and 2 The pilot unit Solvent Lights Column 1 shown in , was first operated at 25 psig during the test period. A feed stream 10 comprising crude propylene oxide (intermediate stream from the PO / TBA process) is fed to solvent lights column 1 at a point in the middle of the column. Table 5 shows the concentrations of key impurities in the feed stream, each expressed as a weight percent of the total composition.

[0073]

[0074] Using multiple temperature probes TE2112, TE2111, TE2110, TE2108, TE2107, TE2105, TE2113, TE2109 and TE2138, the positions are as figure 2 shown in .

[0075] The temperature of feed stream 10 was 27°C and the flow rate was 3.0 kg / hour. Entering at the top of the column is a lean solvent containing stream 32 pumped from the bottom of the solvent stripper column 3, as figure 1 shown in . Solvent stripper 3 is also shown in more detail in image 3middle. The flow rate of lean solvent in stream 32 ...

Embodiment 2

[0088] Unexpected beneficial results can also be obtained by reducing the amount of water, methanol and / or glycol concentration in the solvent-lights column 1 feed. Two concentrations of methanol (MeOH) were tested using the same pilot unit as described in Example 1. One experiment used a propylene oxide feed containing 0.1172% by weight MeOH, as shown in Table 5. Another experiment used a feed with 0.0032 wt% MeOH, as shown in Table 9. The feed stream comprising the propylene oxide feed stream is the crude PO stream from the PO / TBA process. Both Tables 5 and 9 show the concentrations of key impurities in the feed stream, each expressed as a weight percent of the total composition of the crude PO stream from the PO / TBA process.

[0089]

[0090] With reduced MeOH in the PO feed, removal of both formaldehyde and acetaldehyde is unexpectedly improved, as shown by reduced aldehyde levels in solvent stripper overhead 34 . Without wishing to be bound by theory, it is possible...

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PUM

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Abstract

The disclosure relates to a process for separating propylene oxide for a crude propylene oxide stream, for example an intermediate stream from a PO / TBA process. The crude propylene oxide stream can be passed through an extractive distillation column. The distillation column is operated at a pressure in a range of greater than 25 up to 50 psig, and / or at a temperature in a range of from 70 to 150 degrees Celsius using C8-C20 paraffin as extractive solvent with an overhead distillate water wash drum. The crude propylene oxide stream include from 0.001 to 0.1 wt % methanol, based on the total composition of the crude propylene oxide stream. The systems, methods, and apparatuses can produce a propylene oxide stream having less formaldehyde and acetaldehyde than the prior art.

Description

field of invention [0001] The present invention relates to a process for the purification and recovery of propylene oxide formed from the epoxidation of propylene with hydroperoxides derived from the oxidation of isobutane, ethylbenzene or cumene. In particular, the present method improves the separation of light aldehydes, such as formaldehyde and acetaldehyde, from propylene oxide. Background of the invention [0002] About 14.5 billion pounds of propylene oxide are produced annually. Propylene oxide has many uses. To make polyurethane plastics, 60-70% of the total propylene oxide is converted into polyether polyols. About 20% of propylene oxide is hydrolyzed to propylene glycol by a process accelerated by a thermal reaction or by acid or base catalysis. Other main products are polypropylene glycol, propylene glycol ethers and propylene carbonate. To prepare these end products, propylene oxide free from impurities is required. [0003] Processes for the preparation o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D301/19C07D301/32C07D303/04
CPCC07D301/32C07D303/04C07D301/19B01D3/40
Inventor 李向民D.W.利雄张锑
Owner LYONDELL CHEM TECH LP
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