JP5119122B2 - Method for removing oxygen-containing compounds from crude hydrocarbons and method for producing purified hydrocarbons - Google Patents

Description

  The present invention relates to a method for removing oxygen-containing compounds from crude hydrocarbons and a method for producing purified hydrocarbons using the method. Specifically, the present invention relates to a method for removing oxygen-containing compounds such as alcohols and ethers from crude hydrocarbons and a method for producing purified hydrocarbons using the method.

When raw materials such as natural gas, refinery gas or certain petroleum fractions are pyrolyzed or pyrolytically / catalytically cracked with a steam cracker, etc., the cracked products are post-treated to produce butadiene, butanes, n
-Crude hydrocarbons containing hydrocarbons such as butenes and isobutene are obtained.

  These crude hydrocarbons contain various oxygen-containing compounds and nitrogen-containing compounds as impurities in addition to the hydrocarbons described above. The types and amounts of these impurities depend on the type and origin of the raw materials used or the technical conditions of the decomposition reaction. The amount of impurities is also affected by further post-treatment of the crude hydrocarbon.

  One use of crude hydrocarbons is the synthesis of propylene by a metathesis reaction of n-butenes contained in the crude hydrocarbons. When carrying out the metathesis reaction, oxygen-containing compounds, nitrogen-containing compounds, etc. contained as impurities in the crude hydrocarbon used will cause the deactivation of the metathesis catalyst and must be removed in advance. .

  Incidentally, as a method of removing water, alcohol, nitrogen compound, sulfur compound and halogen compound contained in crude hydrocarbon by adsorption onto a solid adsorbent such as alumina or zeolite, Patent Document 1 discloses a hydrocarbon mixture. In order to oligomerize the catalyst with a nickel-containing catalyst, before the oligomerization, the hydrocarbon mixture is led onto a zeolite (molecular sieve) having a pore size exceeding 4 to 15 mm, and a catalyst poison such as water, alcohol, propylene and butadiene is multiplexed. A method for removing unsaturated hydrocarbons is described.

  Further, in Patent Document 2, as a method for reducing the content of oxygen-containing compounds and nitrogen-containing compounds in a material flow containing at least 10% by mass of isobutene, the material flow is reduced to an average pore size of 0.3 to 1.5 nm. It is described that conduction is made to a fixed bed of acid-free zeolite.

However, these methods are still insufficient for removing oxygen-containing compounds such as alcohols and ethers from crude hydrocarbons in which highly polar alcohols and less polar ethers coexist, and there is room for improvement. there were.
Japanese Patent No. 2726138 Special table 2007-508254 gazette

  An object of the present invention is to provide a method for removing oxygen-containing compounds such as ethers and alcohols from crude hydrocarbons, and a method for producing purified hydrocarbons using the method.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an adsorption column (i) filled with a hybrid adsorbent composed of a mixture of activated alumina and zeolite and an adsorption column (ii) filled with a zeolite adsorbent. ), The crude hydrocarbon is brought into contact with the hybrid adsorbent layer and then the zeolite adsorbent layer in this order, whereby the oxygenated compounds in the crude hydrocarbon are efficiently removed and the invention is completed. It came to.

That is, the present invention includes the following items (1) to (6).
(1) A method for removing an oxygen-containing compound from a crude hydrocarbon containing an oxygen-containing compound as an impurity, wherein the crude hydrocarbon is packed with a hybrid adsorbent composed of a mixture of activated alumina and zeolite (i And then contacting an adsorption column (ii) packed with a zeolitic adsorbent to remove the oxygen-containing compound from the crude hydrocarbon.
(2) The hybrid adsorbent is a mixture of 20 to 80% by weight of activated alumina and 80 to 20% by weight of zeolite (the total of activated alumina and zeolite is 100% by weight). the method of.
(3) The use ratio of the hybrid adsorbent and the zeolite adsorbent is a hybrid adsorbent: zeolite adsorbent = 1: 1 to 8: 1 in a volume ratio (1) or (1) The method according to 2).
(4) A method for producing a purified hydrocarbon by removing an oxygen-containing compound from a crude hydrocarbon containing an oxygen-containing compound as an impurity, the hybrid hydrocarbon comprising a mixture of activated alumina and zeolite A method for producing purified hydrocarbons, comprising contacting an adsorption column (i) packed with a catalyst and then contacting an adsorption column (ii) packed with a zeolite-based adsorbent.
(5) The hybrid adsorbent is a mixture of 20 to 80% by weight of activated alumina and 80 to 20% by weight of zeolite (the total of activated alumina and zeolite is 100% by weight). A method for producing purified hydrocarbons.
(6) The use ratio of the hybrid adsorbent and the zeolite adsorbent is a hybrid adsorbent: zeolite adsorbent = 1: 1 to 8: 1 in a volume ratio (4) or (4) A method for producing a purified hydrocarbon according to 5).

  ADVANTAGE OF THE INVENTION According to this invention, the refinement | purification hydrocarbon from which the oxygen-containing compound used as a catalyst poison at the time of synthesize | combining a propylene using a metathesis reaction from a crude hydrocarbon was efficiently removed can be manufactured.

Hereinafter, the present invention will be described in detail.
The method for removing an oxygen-containing compound from a crude hydrocarbon of the present invention is a method for removing an oxygen-containing compound from a crude hydrocarbon containing an oxygen-containing compound as an impurity, the crude hydrocarbon being a mixture of activated alumina and zeolite. It is characterized in that it is brought into contact with an adsorption column (i) filled with a hybrid type adsorbent comprising, and then brought into contact with an adsorption column (ii) filled with a zeolite type adsorbent.

  Examples of the crude hydrocarbon used in the present invention include C4 fractions mainly composed of butadiene, butanes, n-butenes and isobutene, C4 raffinate-1, C4 raffinate-2 and the like. The C4 fraction is a light product obtained by fluidized bed catalytic cracking (FCC) of heavy hydrocarbons, and other than the main fractions such as gasoline and gas oil, mainly isobutane, isobutene, A hydrocarbon fraction consisting of n-butene and butane and containing a small amount of 1,3-butadiene and acetylene hydrocarbon. Further, C4 raffinate-1 refers to a residue obtained by extracting butadiene from a C4 fraction produced by a cracker, and C4 raffinate-2 refers to a residue obtained by extracting isobutene from C4 raffinate-1. In addition, as a crude hydrocarbon used other than C4 fraction, C4 raffinate, etc., the crude hydrocarbon etc. which have C5 fraction, C6 fraction, and C7 fraction as a main component are mentioned.

  The crude hydrocarbon used in the present invention contains an oxygen-containing compound as an impurity. This oxygen-containing compound is usually contained as an impurity in the C4 fraction, C4 raffinate-1 and C4 raffinate-2, such as water; alcohols such as methanol, ethanol and t-butanol; dimethyl ether, methyl-t- And ethers such as butyl ether, isopropyl-t-butyl ether and isobutyl-t-butyl ether.

  The content of ethers in the crude hydrocarbon used in the present invention is usually 50 to 200 ppm, and the upper limit is preferably 150 ppm or less. If the ether content exceeds the above range, the column needs to be enlarged in order to remove the oxygen-containing compound, which may be impractical or may be insufficiently removed by the column.

In the present invention, purified hydrocarbons are those obtained by adsorbing and removing oxygen-containing compounds from crude hydrocarbons.
The hybrid adsorbent and zeolite adsorbent used in the present invention will be described below.

  The hybrid adsorbent used in the present invention is composed of a mixture of activated alumina and zeolite, and is usually 20 to 80% by weight of activated alumina and 80 to 20% by weight of zeolite in a total of 100% by weight of activated alumina and zeolite, preferably It consists of a mixture of 30-70% by weight activated alumina and 70-30% by weight zeolite. A commercial product may be used as the hybrid adsorbent. By placing the adsorption column (i) filled with the hybrid adsorbent in front of the adsorption column (ii) filled with the zeolite adsorbent described later, among the oxygenated compounds contained as impurities in the crude hydrocarbon Highly polar components such as water and alcohol can be removed.

  The activated alumina that constitutes the hybrid adsorbent is the one obtained by transferring alumina hydroxide to porous aluminum oxide with low crystallinity to give adsorption capability, and has a high specific surface area and high pore volume, and is excellent Has adsorption capacity. The activated alumina may be a commercially available product, or may be produced by a known method.

The pore diameter of the activated alumina is usually 1.5 to several tens of nm. It is preferable that the average particle diameter and the pore diameter of the activated alumina are in the above-mentioned range because highly polar impurities such as water and alcohol can be adsorbed efficiently.

Although it does not restrict | limit especially as a preferable activated alumina, (gamma) -alumina etc. are mentioned.
The zeolite constituting the hybrid adsorbent can be synthetically produced by a known method. Known methods include, for example, the method described in “Ullmanns Enzyklopaedied. Techn. Chemie”, 1983, 4th edition, volume 17, p. 9-17. As a method for producing zeolite, a sodium aluminate (NaAlO ₃ ) aqueous solution, a sodium silicate aqueous solution, and a sodium hydroxide aqueous solution are used as raw materials, heated and held for several hours to crystallize to obtain a zeolite powder. Next, the obtained zeolite powder is mixed with a viscosity mineral, silica sol or alumina sol, or a binder (binder) obtained by adding an organic substance to these, and granulated and sintered.

  The average pore diameter of the zeolite is usually 0.2 to 1 nm, preferably 0.5 to 1 nm. It is preferable that the average pore diameter of the zeolite is in the above range because various impurities including ethers can be efficiently adsorbed. The average pore diameter is determined by the crystal structure, and the crystal structure can be calculated from X-ray structure data or the like.

Although it does not restrict | limit especially as a preferable zeolite, Zeolite X, Y, A, etc. are mentioned, Especially preferably, zeolite X etc. are mentioned.
As the zeolitic adsorbent used in the present invention, the same zeolite adsorbents as those constituting the hybrid adsorbent layer can be used. In a conventional adsorption column packed only with a zeolite adsorption layer, if many impurities such as water and alcohol are contained, these impurities have affinity with the zeolite adsorbent, so low polarity impurities such as ethers are sufficient. However, by placing the adsorption column (ii) after the adsorption column (i), water, alcohol, etc. are first adsorbed and removed by the adsorption column (i) which is a hybrid adsorbent layer. Therefore, ethers can be efficiently adsorbed by the adsorption column (ii) which is a zeolite adsorbent layer.

  The particle size of the zeolitic adsorbent used in the present invention is not particularly limited, but the average pore size is usually 0.2 to 1 nm, preferably 0.5 to 1 nm. When the average pore diameter of the zeolitic adsorbent is within the above range, various impurities in the crude hydrocarbon described above can be efficiently removed.

The use ratio of the hybrid type adsorbent and the zeolite type adsorbent packed in the adsorption column (i) and the adsorption column (ii), respectively, is usually a hybrid type adsorbent: zeolite type adsorbent = 1: 1 to 8 in volume ratio. : 1, preferably 1: 1 to 4: 1. When the zeolitic adsorbent is larger than the usage rate (volume ratio) of the hybrid sorbent, or when the zeolitic adsorbent usage rate (volume ratio) to the hybrid adsorbent is smaller than the above range, the crude carbonization The ability to remove impurities in hydrogen may be reduced. The reason for the former is that zeolitic adsorbents also adsorb unsaturated hydrocarbons, so unsaturated hydrocarbons may polymerize on the adsorbents and crush the pores. Although it is necessary to prevent it by carrying out, it is mentioned that the hybrid type adsorption agent containing this activated alumina is required in said ratio. The reason for the latter is that the amount of the zeolite adsorbent is too small, so that the adsorption ability of impurities in the crude hydrocarbon is lowered.
The adsorption column used in the present invention comprises an adsorption column (i) filled with a hybrid adsorbent composed of a mixture of activated alumina and zeolite, and an adsorption column (ii) filled with a zeolite adsorbent.

  The hybrid adsorbent and the zeolite adsorbent are packed in a fixed bed type adsorption column. The adsorption column (i) and the adsorption column (ii) may be arranged vertically, may be inclined or arranged horizontally, but are preferably arranged vertically. The crude hydrocarbon stream is also conducted in the direction of gravity or opposite to gravity. The length of the fixed bed in the flow direction is preferably at least twice the (longest) diameter of the fixed bed. Alternatively, the adsorption column (i) may be arranged on the upstream side and the adsorption column (ii) may be arranged on the downstream side, and a plurality of them may be connected in series.

  The crude hydrocarbon is brought into contact with the hybrid adsorbent in the adsorption column (i), mainly adsorbing water, alcohols and a portion of ethers, and brought into contact with the zeolite adsorbent in the adsorption column (ii). , Ethers are adsorbed.

The linear velocity of the crude hydrocarbon stream is usually 0.001 to 0.005 m / sec, preferably 0.002 to 0.003 m / sec. Here, the linear velocity is a value obtained by dividing the volume flow rate (m ³ / sec) by the cross-sectional area (unit: m ² ) of the adsorption layer.

The temperature of the adsorption column (i) and the adsorption column (ii) when adsorbing impurities such as ethers from the crude hydrocarbon is not particularly limited as long as the crude hydrocarbon is not solidified or vaporized. It is preferable that it is 70 degreeC.

Further, the pressure of the adsorption treatment is not particularly limited as long as the crude hydrocarbon is not vaporized.
The hybrid adsorbent in the adsorption column (i) after the operation period of the adsorption treatment and the zeolite adsorbent in the adsorption column (ii) are adsorbed on the surface with impurities such as ethers. Further, the impurities cannot be sufficiently adsorbed and removed even if they are conducted. The hybrid adsorbent and zeolite adsorbent in such a state can be regenerated by circulating an inert gas such as nitrogen at a temperature of 150 to 250 ° C. under ambient pressure or reduced pressure. A typical regeneration cycle is 24-48 hours.

  It is advantageous in terms of efficiency if at least two series of adsorption columns are provided and the second series of columns can be regenerated while the first series of columns adsorbs ethers and the like. That is, if the adsorbent of the first column (adsorption column (i) + adsorption column (ii)) is saturated with impurities, the crude hydrocarbon stream is passed through the second adsorption column (adsorption column (i) + adsorption It is efficient to divert toward the column (ii)) and regenerate the adsorbent of the first column while the adsorbent of the second adsorption column adsorbs ethers and the like.

After the adsorption treatment according to the present invention, the concentration of ethers contained in the purified hydrocarbon is usually less than 1 ppm.
The method for producing purified hydrocarbons of the present invention is a method for obtaining purified hydrocarbons by removing oxygenated compounds from crude hydrocarbons containing oxygenated compounds as impurities, and the crude hydrocarbons are obtained from activated alumina and zeolite. It is characterized in that it is brought into contact with an adsorption column (i) filled with a hybrid adsorbent comprising a mixture and then brought into contact with an adsorption column (ii) filled with a zeolite adsorbent.

  In the above purified hydrocarbon production method, the hybrid adsorbent is preferably a mixture of 20 to 80% by weight of activated alumina and 80 to 20% by weight of zeolite (the total of activated alumina and zeolite is 100% by weight), The use ratio of the hybrid adsorbent and the zeolite adsorbent is preferably hybrid adsorbent: zeolite adsorbent = 1: 1 to 8: 1 in a volume ratio.

〔Example〕
EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these Examples at all.

[Example 1]
A hybrid adsorbent (UOP / manufactured with crude hexane containing methyl-t-butyl ether (MTBE) and dimethyl ether (DME) as ethers and t-butyl alcohol (TBA) and methanol as alcohols in the concentrations shown in Table 1 The adsorption column (i) (height 500 mm, inner diameter 25 mm) packed with Union Showa Co. AZ-300) was conducted. Under conditions of room temperature, pressure of about 0.14 MPaG and linear velocity of 0.003 m / sec (flow rate of 95 ml / min), the purified hexane flowing out from the column outlet was sampled every 10 to 60 minutes after the flow, and the purified hexane was The concentration of MTBE, DME, TBA and methanol contained was measured. MTBE and DME were measured with a gas chromatograph mass spectrometer (GC / MS), and TBA and methanol were measured with a gas chromatograph analyzer (GC).

  The results are shown in FIG.

  When the crude hexane was passed, MTBE having a low polarity flowed out of the column 20 minutes after the conduction. From the curve of the graph shown in FIG. 1, the concentration of the oxygen-containing compound in the purified hexane that has flowed out after 50 minutes is 50 ppm.

  Even with ethers, DME having a molecular size smaller than that of MTBE took longer to start flowing out of the column outlet than MTBE, but it flowed out of the column after 90 minutes and flowed out by 1 ppm or more after 150 minutes.

On the other hand, TBA and methanol having higher polarity than ethers did not flow out of the column.
As shown in FIG. 1, in the adsorption column (i) packed with a hybrid adsorbent, alcohols are preferentially removed, and ethers having a lower polarity than alcohols, particularly ethers having a low molecular weight are in the presence of alcohol. It is clear that it is difficult to remove.

  Next, the crude hexane containing 50 ppm MTBE and a small amount of DME collected after 200 minutes passed through the adsorption column (i) was converted into a zeolite adsorbent (F-9 manufactured by Tosoh Corporation; average pore diameter of 1 nm). ) Was packed into the adsorption column (ii) (height 500 mm, inner diameter 25 mm). Purified hexane was sampled out of the column outlet every 10 to 30 minutes by flowing under conditions of room temperature, pressure of about 0.14 MPaG and linear velocity of 0.003 m / sec (flow rate of 95 ml / min), and contained in the purified hexane. The concentration of MTBE and DME was measured. MTBE and DME were measured with a gas chromatograph mass spectrometer (GC / MS).

The results are shown in FIG.
As shown in FIG. 2, MTBE did not flow out of the column until 90 minutes had passed after conduction.

[Comparative Example 1]
At the concentrations shown in Table 2, crude hexane 1 containing MTBE and DME as ethers and TBA and methanol as alcohols and crude hexane 2 containing only MTBE were passed through only the adsorption column (i). Purified hexane 1 and purified hexane 2 that flowed out of the adsorption column (i) every 10 to 30 minutes are sampled, and the concentrations of MTBE, DME, TBA, and methanol contained in purified hexane 1 and purified hexane 2 are the same as in Example 1. The measurement was performed in the same manner.

  The results are shown in FIG.

  As is clear from FIG. 3, when crude hexane 1 was passed, low polarity ethers (MTBE) began to flow out of the adsorption column (i) from about 10 minutes after conduction, but high polarity alcohols. (TBA and methanol) did not flow out. From this result, it is understood that when the adsorption treatment is performed using only the hybrid adsorbent in the presence of alcohols and ethers, the alcohols are preferentially removed and the ethers cannot be sufficiently removed. .

  In crude hexane 2 containing only MTBE, MTBE did not flow out of the column until 30 minutes after conduction, even though the concentration of MTBE was twice that of crude hexane 1. That is, it can be seen from FIG. 3 that the hybrid adsorbent has the ability to adsorb a certain amount of ethers, and in the absence of alcohol, more ethers can be removed than in the presence of alcohol. Recognize.

[Comparative Example 2]
At the concentrations shown in Table 3, a crude hexane 1 containing MTBE and DME as ethers, TBA and methanol as alcohols, and a crude hexane 2 containing only MTBE as ethers were passed through only the adsorption column (ii). . The purified hexane 1 and purified hexane 2 that flowed out of the adsorption column (ii) are sampled every 10 to 30 minutes, and the concentrations of MTBE, DME, TBA, and methanol contained in the purified hexane 1 are measured in the same manner as in Example 1. did.

  The results are shown in FIG.

  As is clear from FIG. 4, when crude hexane 1 was passed, low polarity ethers (MTBE) began to flow out of the adsorption column (ii) from about 60 minutes after conduction, but high polarity alcohols. (TBA and methanol) did not flow out. From this result, even when the adsorption treatment is performed using only the zeolite adsorbent in the presence of alcohols and ethers, the alcohols are preferentially removed, and the ethers cannot be sufficiently removed. Recognize.

  The purified hydrocarbon obtained by the present invention is suitably used as a raw material for producing propylene by a metathesis reaction.

FIG. 1 is a graph showing the concentrations of MTBE, DME, TBA and methanol in purified hexane when crude hexane is passed through only an adsorption column (i) packed with a hybrid adsorbent in Example 1. FIG. 2 is a graph showing the concentration of MTBE in purified hexane when crude hexane was passed through the adsorption column (i) in Example 1 and then passed through the adsorption column (ii) packed with the zeolite-based adsorbent. is there. FIG. 3 is a graph showing the concentrations of MTBE, DME, TBA and methanol in purified hexane when the crude hexane is passed through only the adsorption column (i) packed with the hybrid adsorbent in Comparative Example 1. FIG. 4 is a diagram showing the concentrations of MTBE, DME, TBA and methanol in purified hexane when the crude hexane is passed through only the adsorption column (ii) packed with a zeolite-based adsorbent in Comparative Example 2.

Claims (6)

A method for removing an oxygen-containing compound from a crude hydrocarbon containing an oxygen-containing compound as an impurity, the crude hydrocarbon comprising:
Contacting an adsorption column (i) packed with a hybrid adsorbent comprising a mixture of activated alumina and zeolite;
A method for removing an oxygen-containing compound from a crude hydrocarbon, which is brought into contact with an adsorption column (ii) packed with a zeolite-based adsorbent.   The method according to claim 1, wherein the hybrid adsorbent is a mixture of 20 to 80% by weight of activated alumina and 80 to 20% by weight of zeolite (a total of 100% by weight of activated alumina and zeolite).   The use ratio of the hybrid adsorbent and the zeolite adsorbent is a hybrid adsorbent: zeolite adsorbent = 1: 1 to 8: 1 in a volume ratio. Method. A method for producing a purified hydrocarbon by removing an oxygen-containing compound from a crude hydrocarbon containing an oxygen-containing compound as an impurity, the crude hydrocarbon comprising:
Contacting an adsorption column (i) packed with a hybrid adsorbent comprising a mixture of activated alumina and zeolite;
A method for producing a purified hydrocarbon, comprising contacting an adsorption column (ii) filled with a zeolite-based adsorbent.   The refined carbonization according to claim 4, wherein the hybrid adsorbent is a mixture of 20 to 80% by weight of activated alumina and 80 to 20% by weight of zeolite (a total of 100% by weight of activated alumina and zeolite). A method for producing hydrogen.   The use ratio of said hybrid type adsorbent and zeolite type adsorbent is a hybrid type adsorbent: zeolite type adsorbent = 1: 1 to 8: 1 in a volume ratio. A method for producing purified hydrocarbons.

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