CN1103606A - Methane-oxidizing and -coupling radial fixed-bed reactor - Google Patents

Abstract

In the said reactor, two perforated separating cylinders with catalyst filled in between are concentrically mounted and the interval between the two cylinders is adjustable for changing the thickness of catalyst bed layer. During operation, the reactant entering the inner cylinder through the inlet at the center of cylinders passes through the catalyst bed radially and the out cylinder and exhausts through the outlet. By reducing the thickness of catalyst bed to prevent multiple reaction, the said reactor can raise the selectivity and yield of C2 hydrocarbon and increase catalyst loading level and space velocity of reactant, adapting large scale production.

Description

Methane-oxidizing and -coupling radial fixed-bed reactor

The present invention relates to a kind of catalyst reaction device, specifically provide a kind of radial flow fixed-bed reactor that are used for the methane-oxidizing and-coupling reaction.

Methane oxidation coupling system ethene has great economic implications and theoretical value, and extensively causes people's attention.The fixed-bed reactor that are used for this class building-up reactions at present are to adopt the traditional fixed bed continuous reactor of axial aeration type.Use the thickness of this reactor catalyst bed to increase with loaded catalyst, but when the bed of catalyzer thicker, when the air speed of methane reaction gas was big, the temperature of beds will rise very highly, is easy to generate a large amount of CO _X, make C ₂The selectivity and the yield of hydrocarbon significantly descend.For the yield that keeps ethene does not increase the catalyst bed layer thickness again, can only increase the caliber of crude reaction device, radially distribute very inhomogeneously but adopt this treatment process will cause bed temperature, not only will influence the service efficiency and the reduction C of catalyzer ₂Hydrocarbon-selective and yield also will bring difficulty to device fabrication, make the oxidative coupling of methane industrial applications bring difficulty.

The purpose of this invention is to provide a kind of fixed-bed reactor that oxidative coupling of methane is used that are suitable for, adopt this reactor can avoid the various unfavorable factors of above-mentioned ordinary fixed bed bioreactor, reach and have radially uniform distribution of thin beds and bed temperature, can increase simultaneously the usage quantity of catalyzer again, improve the air speed of reactants, methane gas, increase productive rate, make it to be beneficial in suitability for industrialized production and adopt.

For achieving the above object, the present invention has designed a kind of radial flow dynamic formula reactor, be reactant (gas) be along reactor radially pass beds, the thickness of the catalyst reactor bed of this structure is very easy to control, and is not subjected to the influence of loaded catalyst.Because beds can design thinlyyer, be used for methane-oxidizing and-coupling reaction can reduce or avoid methane and generate CO _XReaction, improve C thereby reach ₂The selectivity of hydrocarbon and yield.Increase reactor length simultaneously, can realize increasing catalyst consumption, be suitable for the high-speed running and improve productive rate to be suitable for the industrialization employing.Radial flow fixed-bed reactor specifically of the present invention are a closed cylinder type reactor, the two-layer dividing plate tube with holes of concentric device in the reactor, loading catalyst between two inwalls, the spacing of dividing plate tube can be adjusted, to reach the beds of selecting suitable thickness, be generally 5～25mm, one end (bottom) center drilling of reactor is as reactant entrance, and communicate with internal partition tube inwall, the other end (top) by the perforate of reacting cylinder body edge as reacting product outlet and with external partition drum outer wall and cylinder inboard wall between communicate.Reactor cylinder also can add thermal insulation layer outward, and other sets up heating unit and temperature tube etc. parts and make practical reactor.In addition, reactor one end (top) can be designed to adorn the flange of folding, takes off flange and can load (or taking-up) catalyzer between two dividing plate tubes in reactor, simultaneously behind the catalyst loading, add an obturator between its blind flange and catalyzer, to reduce dead volume in the reactor.Accompanying drawing 1 is the structural representation of reactor of the present invention.Among the figure: 1. reacting cylinder body; 2. outer porous barrier tube; 3. internal layer porous barrier tube; 4. catalyst layer; 5. inlet mouth; 6. air outlet; 7. obturator; 8. loam cake flange; 9. well heater; 10. temperature tube; 11. reactor outer wall.Above-mentioned the utility model reactor, the all available stainless steel plates of parts such as its reacting cylinder body, dividing plate tube, flange are made, the available stainless steel plate of dividing plate tube is processed into even porous, and (aperture can be Φ 1～5mm, look catalyst grain size) or the stainless steel plate stretching nets make, percentage of open area should be beneficial to reactant and evenly pass through catalyst surface greater than 40%.Below in conjunction with example technology of the present invention is described further.

Example 1 radial flow fixed-bed reactor

Structure with reference to reactor shown in the accompanying drawing 1, make Φ 40mm external diameter reacting cylinder body 1 with the 2.0mm stainless steel plate, cylindrical shell 1 upper end adds steel flange loam cake 8, cylindrical shell 1 bottom centre has inlet mouth 5(and inlet pipe), the top outer rim has air outlet 6(and escape pipe), have even Φ 3mm aperture with the 1.0mm stainless steel plate again, perforate is greater than 75%, make Φ 8mm and Φ 18mm porous barrier tube, be fixed on one heart outside the cylindrical shell 1 interior formation, internal layer porous barrier tube 2,3, two dividing plate tube spacings are about 9mm.Cylindrical shell 1 adds the nichrome wire of having heaters 9, and is surrounded by thermal insulation material formation reactor outer wall 11 outside it.Temperature tube 10(installs respectively in internal layer porous barrier tube for three groups, in the beds 4 and outer porous barrier tube outer) in thermocouple is housed with each position temperature in the test reaction.Catalyst loading in outside, between interior porous barrier tube after, on catalyzer, add suitable ceramic bead or glasscloth and make obturator 7 and fill up in the reacting cylinder body, add that to cover flange 8 fixing, and keep sealing in the reacting cylinder body.Reactant gases was entered in the reactor cylinder by inlet mouth 5 when this reactor moved, and radially passed beds along reaction tube and arrived cylindrical shell 1 inwall, discharged reactors by air outlet 6.

Example 2 radial reactors are used for methane oxidation coupling synthesizing ethylene reaction 1

Utilize example 1 made reactor, get the 50mlLi-MgO catalyzer and load in the reactor, the catalyst bed layer thickness is 9mm, and methane/oxygen ratio is about 2.8, adds water 108ml/hr in unstripped gas simultaneously, and the wall temperature of reactor is controlled at 780 ℃, and the air speed of methane gas is 5000hr ^-1, catalyzed reaction result is as follows:

O ₂CH ₄CO ₂CO C ₂H ₄C ₂H ₆CH ₄Transformation efficiency % C ₂Hydrocarbon-selective % C ₂Yield %

4.8 68.1 13.9 3.5 8.2 1.6 35.2 53.0 18.6

Comparative example 1 synthesizing ethylene reaction 1

Utilize common tubular reactor, get the thick 4mm of being of 1ml and example 1 same catalyst loading catalyst bed, other reaction conditions is identical with example 1, its CH ₄Transformation efficiency 26.7%, C ₂Hydrocarbon-selective 65.6%, C ₂Hydrocarbon yield 17.5%.

Example 2 radial reactors are used for methane oxidation coupling synthesizing ethylene reaction 2,3

Press the similarity condition of example 1, just improve CH ₄Air speed to 7700hr ^-1And 10000hr ^-1, flooding quantity increases to 141ml/hr, and reaction result is as follows:

Air speed hr ^-1O ₂CH ₄CO ₂CO C ₂H ₄C ₂H ₆CH ₄Transformation efficiency %

7700 4.8 66.4 14.9 3.5 8.8 1.6 37.1

10000 4.4 69.5 13.0 2.5 8.8 1.9 34.7

C ₂Hydrocarbon-selective % C ₂Yield %

53.1 19.7

58.0 20.1

From above result, adopt radial film reactor of the present invention, the catalyzer loading amount is 50ml, the methane air speed is with 5000hr ^-1To 10000hr ^-1, the C of gained ₂The hydrocarbon yield is better than the result of the lab scale of catalyst-assembly 1ml.

Example 3 radial reactors are used for methane oxidation coupling synthesizing ethylene reaction 4

Utilize example 1 reactor, get the 200mlLa-BaO catalyzer and be contained in the reactor, the reactor wall temperature is 780 ℃, and the methane gas air speed is 10000hr ^-1, flooding quantity is 50ml/hr, CH ₄/ O ₂Be 6.7, reaction result is as follows:

O ₂CH ₄CO ₂CO C ₂H ₄C ₂H ₆CH ₄Transformation efficiency % C ₂Hydrocarbon-selective % C ₂Yield %

0.8 81.4 5.7 3.4 5.4 2.3 24.5 62.7 15.3

Comparative example 2 synthesizing ethylenes reaction 2

Utilize common tubular reactor, getting 30mlLa-BaO catalyst loading bed is 20mm, and other reaction conditions is identical with example 3, and catalyzed reaction result is as follows:

O ₂CH ₄CO ₂CO C ₂H ₄C ₂H ₆CH ₄Transformation efficiency % C ₂Hydrocarbon-selective % C ₂Yield %

1.9 78.5 8.9 4.0 4.9 1.7 25.0 50.6 12.6

From above result as seen, use the ordinary fixed bed bioreactor, when the catalyzer loading amount more for a long time, catalytic perfomance degenerates, C ₂The hydrocarbon yield descends.

Claims (3)

1, fixed-bed reactor are used in the reaction of a kind of methane oxidation coupling synthesizing ethylene, it is characterized in that adopting radial flow dynamic formula reactor, and promptly reactant (gas) radially passes beds along reactor; Its reactor is an airtight cylindrical shell, the inside and outside two-layer dividing plate tube with holes of concentric device in the cylindrical shell, and loading catalyst between two inwalls, the spacing of two dividing plate tubes can be adjusted, to change the thickness of bed layer of catalyzer; Cylindrical shell one end center drilling is as reactant entrance, and communicates with internal partition tube inwall, the cylindrical shell the other end by the perforate of cylindrical shell edge as the reactant air outlet, and with external partition drum outer wall and cylinder inboard wall in communicate.

2,, it is characterized in that inside and outside two-layer dividing plate tube spacing with holes is 5～25mm according to the described reactor of claim 1.

3, according to the described reactor of claim 1, it is characterized in that its cylindrical shell can be made by stainless steel plate, dividing plate tube with holes can evenly be opened Φ 1～5mm hole or stainless steel stretched web plate is made by stainless steel plate, and its percentage of open area should be greater than 40%.

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