JPS6245543A - Production of lower unsaturated hydrocarbon - Google Patents

Abstract

PURPOSE:To produce a lower unsaturated hydrocarbon, by passing a lower unsaturated hydrocarbon containing impurities through a pretreating adsorbent bed and then a normal treating adsorbent bed to remove the residual impurities and adsorbed impurities and desorbing the lower unsaturated hydrocarbon. CONSTITUTION:A lower unsaturated hydrocarbon (unsaturated HC) containing impurities is passed through a pretreating adsorbent bed to remove the impurities having higher adsorbability than the unsaturated HC. The unadsorbed component is then passed through a normal TREATING adsorbent bed, e.g. zeolite 4A or 5A, to adsorb the unsaturated HC thereon. The impurities left in the space part of the normal adsorbent bed are removed by passing preferably a gas flowing out of the normal adsorbent bed in the next treatment of removing the adsorbed impurities therethrough and the adsorbed impurities are removed by circulating a gas present in the adsorbent bed. The normal treating adsorbent bed is heated to desorb the aimed substance or the second high-purity component is passed through the normal treating adsorbent bed to afford a mixed gas.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to lower unsaturated hydrocarbons, that is, carbon atoms of 2 to 4.
This invention relates to a method for producing unsaturated hydrocarbons or high-purity gases containing them.

Prior Art] High purity lower unsaturated hydrocarbons have been produced by rectification or absorption using a solvent.

Problems to be Solved by the Invention The present invention uses an adsorption method that is relatively easy to operate. ′
The object of the present invention is to provide a method capable of producing a high purity mixed gas of a lower unsaturated hydrocarbon of li purity or a lower unsaturated hydrocarbon and a type of gas having a lower adsorption activity.

[Means for Solving the Problems] The present invention provides the following steps: a. Pass lower unsaturated hydrocarbons containing impurities through a pre-treatment adsorbent bed to adsorb impurities that have higher adsorption activity than lower unsaturated hydrocarbons. b. Pass the unadsorbed components in the pretreatment through the main treatment adsorbent bed to adsorb lower unsaturated hydrocarbons (unsaturated HC adsorption treatment), Residual impurity removal treatment to remove impurities remaining in the space), d. Next, adsorption impurity removal treatment to remove impurities adsorbed on the main treatment adsorbent bed), e. Further, the main treatment adsorption bed Desorbs lower unsaturated hydrocarbons from unsaturated H
In the method for producing lower unsaturated hydrocarbons consisting of (C desorption treatment) or in the unsaturated HC desorption treatment described in e. High-purity mixing of lower unsaturated hydrocarbons with a type of gas with lower adsorption activity by passing a type of gas with lower adsorption activity (J: y, below, referred to as "second component") The gist of the process is to introduce the gas into the gas. By doing so, a high purity gas consisting of lower unsaturated hydrocarbons or this and a second component can be obtained.

Examples of lower unsaturated hydrocarbons include ethylene, acetylene, propylene, butylene, etc., and useful second components used in combination with lower unsaturated hydrocarbons include hydrogen, helium, argon, etc. but,
The present invention can be applied to either.

Each step will be explained in detail below.

<Pretreatment> Moisture, carbon dioxide, acetone, dimethylformamide, etc. usually have higher adsorption activity than lower unsaturated hydrocarbons, so they are removed by pretreatment.

As the adsorbent used here, for example, zeolite 3A, zeolite 4Δ, activated carbon, etc. are suitable. When using these, the temperature should be 0 to 20℃ and the absolute pressure should be 1 to 3KF.
This process may be performed at I/cm. The pretreatment adsorbent bed can be made up of two adsorbent beds connected in series, as shown in the drawings (1J3J and 2), to increase the absorption efficiency. In this case, activated carbon is used in the adsorbent bed on the upstream side of the feed gas flow to mainly remove organic impurities, and zeolite 3△ is used in the downstream adsorbent bed.
Alternatively, it is preferable to use Zeolide 4△ to mainly adsorb water.

↑1 treatment> Next to the pretreatment, the gas exiting the +)ff treatment adsorbent bed is passed through the main treatment adsorption bed to adsorb lower unsaturated hydrocarbons, and its non-adsorbed components are Certain impurities are prevented from escaping from the adsorbent bed. These impurities, even (, [, acid wood, nitrogen, carbon oxide, etc.), some of which remain weakly adsorbed on the adsorbent bed.The lower the temperature and the higher the pressure of this process, the more adsorbed Zeolite 4A, which is a suitable adsorbent for this treatment, has a high capacity but also a large amount of adsorbed impurities.
When using zeolite 5△ etc., the temperature is 0 to 70℃, preferably 20 to 60℃, and the temperature is 0 to 131 to 3Kg/
ci is preferably 0.8 to 2 to 9/cti.

Removal of residual impurities〉 When the unsaturated HC adsorption 5 treatment is completed, not only impurities remain in the space of the main treatment absorbent bed, but also the above d3
Usually some of the impurities are weakly adsorbed on the adsorbent.

First of all, the above book 1! [! Remove impurities remaining in the voids of the adsorbent bed. At this time, a portion of the adsorbed impurities is also inevitably attached to the IBM and removed. This process is
Specifically, lower unsaturated hydrocarbons with a certain degree of purity,
This is accomplished by passing the second component or a mixture thereof through the treated adsorbent bed to displace impurities. In order to increase the yield, storing the gas that flows out of the main treatment adsorbent bed in the next adsorbed impurity removal process in a holder and using it is a great way to increase the yield. and
It is sufficient to pass 5 to 20 volumes of the gas present in the adsorbent bed space. This treatment should be carried out at a relatively low temperature so as not to desorb lower unsaturated hydrocarbons, and at a pressure lower than the operating pressure of the unsaturated HC adsorption treatment in order to replace and clean the residual gas.
be. Biolite 4Δ or PiJlite 5 as a suction agent
When using Δ, the temperature is preferably lower than 20°C, preferably 10°C or lower, and the operating pressure is preferably 3Kfl/C or lower absolute pressure.

I'll stop fighting! 1. Removal treatment> Next, impurities adsorbed on the adsorbent of the six-layer absorbent bed for this treatment are removed. This treatment completely desorbs adsorbed impurities and
In addition, the process must be carried out under conditions that make it difficult to remove lower unsaturated hydrocarbons. However, in order to completely desorb impurities, desorption of lower unsaturated hydrocarbons is unavoidable. Passage,
Impurities can be completely desorbed by desorbing 10 to 95%, preferably 10 to 50%, of the lower unsaturated hydrocarbons in the product obtained by the unsaturated HC desorption treatment. If the heating of the adsorbent bed is carried out by passing a gas through the adsorbent bed, this gas must be of high purity.

Although the product obtained from the unsaturated HC process or the second component of high purity melon may be used, it is practical to circulate the adsorbent bed space gas. However, if the purpose is to prepare a gas consisting only of lower unsaturated hydrocarbons, the second component cannot be used.

When using GeA-lite 4A or Geolide 5A as an adsorbent, the final treatment temperature is 20 to 50 °C, preferably 30 to 40 °C, and the pressure is higher than the operating pressure for residual impurity removal treatment. It is preferable to do this so that the gas obtained here can be easily subjected to residual impurity removal treatment in the next cycle.

<Unsaturated HC112 deposition treatment> After the impurity removal treatment, the main treatment adsorbent bed is heated to desorb lower unsaturated hydrocarbons. When producing gas consisting only of lower unsaturated hydrocarbons, heat exchanger tubes are used to
/or product lower unsaturated hydrocarbons this place 1! I! It is heated by passing it through a bed of absorbents. 31. Insert a mixed gas with the second component. ).

If so, the high purity second component must be heated by passing it through the treated adsorbent bed.

In this case, the processing temperature is high (although it is easily removed, it takes a long time to cool down the inhaled material for the next suction treatment. Zeolite 1-4A or Zeolite 1-5
When A is used, this temperature is preferably 40-90°C, preferably 60-80°C.

The treatment temperature in the above-mentioned main treatment adsorbent bed can be adjusted by adjusting the temperature of the gas flowing into it.A heat transfer tube is installed outside or inside the penal code to indirectly heat or
Although it can be easily adjusted by doing a,
As explained above, depending on the type of product gas and other conditions of the production equipment, it is also possible to perform the process using only one of these methods.

"Example] Embodiments of the present invention will be described using figures.

Example 1 Dimedylformamide 71 ppm, water 41 p
pm, carbon dioxide 400 ppm, nitrogen 230
Acetylene containing 0 pOm I; J, BiM as an impurity is passed through valve 4 to Hokuetsu Tansu V Industry
Pre-treated adsorbent bed 1 filled with 682g of loaded talking coal Y-
2u/m1rl (f) flow (passed through D and processed under conditions of 20°C and absolute pressure 131N/clf, then the gas flowing out to the east)
A vs. A-, 20'C through pre-treated adsorbent bed 2 packed with 1151g, absolute JIE L31 K9
/ Cfj's line A'1 [・The gas flowing out from the line passes through valve 5 and reaches Higashidae])' (Zeolide 5 manufactured by Co., Ltd.)
A Zeorum 8-5151Q was passed through the main treatment adsorbent bed 3 containing 20°C and an absolute i of 1.3189/cm.
Processed with. Since the 10mln 3-tube process was saturated with acetylene (confirmed by analyzing the outflow gas), valves 4 and 5 were closed.

Next, the internal pressure of the main treatment adsorbent bed J3 is reduced to an absolute pressure of 0.13 K9/ci using the vacuum pump 7, and the main treatment adsorption bed 3 is transferred to the cold 1 (I L, holder Concentrated impurities stored in 6 5 ppm, absolute)
- "0, 46 K9.7 aj 7-hytylene, cold f,
Cool the adsorbent bed 3 to -10°C with a flask 8 and discharge it from the vacuum pump 7 while reducing the pressure of the adsorbent bed 3 to absolute pressure 0.
A flow rate of 20 volumes (0.4 Nu) of the gas present in the space was passed through the treated adsorbent bed 3 while maintaining the flow rate at 13 tons/'cm. The final eddy current of the treated adsorbent bed 3 was 6°C.

Next, the inhaled criminal law 3 for this treatment is heated to 35°C with the heater 10, and the ahydylene present in the space in the adsorbent bed is transferred to the conduit 14. Main treatment adsorbent bed 3 via blower 12 and regulator 13
The final absolute pressure is 0.46 K! ? /
on, gas at 35°C was collected into holder 6. The impurity level of this gas was 5 ppm.

Next, the concentration of non-containing substances stored in the holder 15 is 0.5.
Aledylene of less than ppm is heated to 80°C with heater 11 and passed through main treatment adsorbent bed 3, and heater 1
1.4 hours of smoking at 80°C (according to the Penal Code) and 0.0 degrees Celsius.
51) l) Acetylene below III? 8 counter pressure 1KF
I/ci, 25°Cm &”) gave 1.09j!.

Example 2 A hydrogen-7-dylene mixed gas was obtained by treating the same 1+% Example 1 and 1'F except for the following conditions.

Pretreatment operating pressure Operating pressure Absolute pressure, 8 to 9/' cl
ri unsaturated IC suction treatment operating pressure absolute pressure 1.8! 1. /Gas in holder 6 for residual impurity removal treatment Impurities 41+pm acetylene 30vo 1% hydrogen 70vo 1% Operating instructions] Standing 0°C Operating pressure Absolute 1〒 1pa3・cni Flowing gas: Uj 7 of the gas present between the beds of the adsorbent for this treatment Volume 11f'H+R Final main treatment adsorbent justice jσ 9°C Adsorption impurity removal treatment Impurities in the supplied gas 1 ppm or less (suction? 1 convex 1 to 11
, circulating the gas in the space Imo-(J Instead of water, (751 was supplied) Operating temperature 25°C 1υ Final pressure Absolute pressure 1.8 Kg/cd Outflow gas temperature 25°C Impurities in the final gas 4ρpHl Unsaturated [-]C ♀ 1-stroke supply gas Impurities 1 ppm or less.

A Operating temperature 70℃ Operating pressure Absolute pressure 5KI/cM Product gas
Impurity lppm acetylene 20vo
1% Hydrogen govo1% Absolute pressure 5 Kg/cni, O℃ conversion 17T 1.25
11 Comparative Example 1 This was carried out under the same conditions as in Example 1 except that no adsorption impurity removal treatment was performed.

Acetylene with an impurity concentration of 2 ppm has an absolute pressure of IK9/
ci, 25℃ conversion r1.62j! Erare7C6

[Brief explanation of drawings]

Figure 1 shows a process diagram of an embodiment of the present invention. Reference numbers in the 15° diagram: 1.2.3: Sucking Penal Code 4.5: or 6.15: Holder 8.9: Cooler 10.11, 13 , 17: Heater patent applicant: Toyo Y1 Kodatsu Kogyo Co., Ltd. Patent applicant: Toho Acedilene Co., Ltd.'\

Claims (4)

[Claims] (1) a. Lower unsaturated hydrocarbons containing impurities are passed through a pretreatment adsorbent bed to adsorb and remove impurities with higher adsorption activity than lower unsaturated hydrocarbons (pretreatment); b. pretreatment Pass the non-adsorbed components in the main treatment adsorbent bed to adsorb lower unsaturated hydrocarbons (unsaturated HC adsorption treatment), c. Next, remove impurities remaining in the spaces of the main treatment adsorption bed. (residual impurity removal treatment), d. Next, remove impurities adsorbed on the main treatment adsorbent bed (adsorption impurity removal treatment); e. Further, lower unsaturated hydrocarbons are desorbed from the main treatment adsorption bed. A method for producing lower unsaturated hydrocarbons, comprising: (unsaturated HC desorption treatment). (2) The residual impurity removal treatment in c. is performed by passing the gas flowing out from the adsorbent bed through the main treatment adsorbent bed in the adsorption impurity removal treatment in d below to remove all of the impurities remaining in the space. A part of the impurities adsorbed on the adsorbent bed is removed, and the adsorbed impurity removal treatment of d) heats the adsorbent bed to remove the remaining impurities adsorbed on the adsorbent bed. The method according to claim (1). (3) a. Passing lower unsaturated hydrocarbons containing impurities through a pretreatment adsorbent bed to adsorb and remove impurities with higher adsorption activity than lower unsaturated hydrocarbons (pretreatment); b. Pretreatment Pass the non-adsorbed components in the main treatment adsorbent bed to adsorb lower unsaturated hydrocarbons (unsaturated HC adsorption treatment), c. Next, remove impurities remaining in the spaces of the main treatment adsorption bed. (residual impurity removal treatment), d. Next, remove impurities adsorbed on the main treatment adsorbent bed (adsorption impurity removal treatment); e. Further, lower unsaturated hydrocarbons are removed from the main treatment adsorption bed, Desorption is carried out by passing a type of gas with lower adsorption activity than lower unsaturated hydrocarbons through the adsorbent bed (unsaturated H
A method for producing a mixed gas of a lower unsaturated hydrocarbon and a type of gas having a lower adsorption activity than the lower unsaturated hydrocarbon. (4) In the adsorption impurity removal process of d below, the residual impurity removal process in c. A part of the impurities adsorbed on the adsorbent bed is removed, and the adsorbed impurity removal treatment of d) heats the adsorbent bed to remove the remaining impurities adsorbed on the adsorbent bed. The method according to claim (3).