JP2015157779A - Device of producing butadiene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device of stably and efficiently producing butadiene from n-butene in a series of regular operations without requiring non-regular operations.SOLUTION: This invention provides a device of producing butadiene from n-butene by fluid catalytic oxidation dehydrogenation reaction, the device comprising a catalyst hopper, a downflow type reactor, a gas-solid separator, and a catalyst regenerator.

Description

  The present invention relates to an apparatus for producing butadiene.

  A method for producing 1,3-butadiene, which is a corresponding conjugated diolefin, by a catalytic oxidative dehydrogenation reaction of n-butene, molecular oxygen and a catalyst is well known, and many reactors have been proposed. ing.

  Examples of the reactor in which the oxide catalyst is used include a fixed bed reactor and a fluidized bed reactor. Fixed bed reactors are widely used industrially, taking advantage of the fact that the gas flow state is close to the extrusion flow and the reaction yield can be increased. However, fixed bed reactors have low heat transfer properties and are not suitable for exothermic or endothermic reactions that require heat removal or heating.In particular, intense exothermic reactions such as oxidation reactions cause the temperature to rise rapidly and become difficult to control. There is a risk that the reaction will run away. Furthermore, there is a problem that the catalyst is damaged by such a rapid temperature rise and deteriorates at an early stage. For example, the oxidative dehydrogenation reaction for synthesizing 1,3-butadiene from butene is an exothermic reaction of about 30 kcal / mol.

  In contrast, the fluidized bed reactor (1) has high heat transfer by vigorously flowing catalyst particles in the reactor, and keeps the reactor temperature substantially uniform even in reactions involving large exotherms and endotherms. (2) Since local accumulation of energy is suppressed, it is possible to react the raw material gas in the explosion range and increase the raw material concentration. There is an advantage that productivity can be improved. Therefore, the fluidized bed reactor is a reactor suitable for oxidative dehydrogenation of hydrocarbons, which is an exothermic reaction. Patent Document 1 describes an example in which a fluidized bed reactor is used for production.

  When 1,3-butadiene is produced from butene, organic substances adhere to the catalyst over time, and the carbon content of the catalyst increases. If this carbon content increases too much, The selectivity is lowered, the fluidity is deteriorated, the catalyst is crushed, and it is difficult to stably produce 1,3-butadiene. For this purpose, Patent Document 2 describes a method for defining the amount of carbon contained in the catalyst, and Patent Document 3 describes a catalyst regeneration method for removing carbon adhering to the catalyst.

JP 2010-120933 A JP 2012-67047 A JP 2012-92092 A

  However, if the oxidative dehydrogenation reaction of n-butene is continued under the conditions where the raw material concentration is increased, the adhesion of organic substances to the catalyst is promoted, so the frequency of catalyst regeneration must be increased. When regenerating a catalyst, a catalyst regeneration facility is required, and unsteady operations such as a process of extracting and transporting the catalyst and a process of treating the catalyst with carbon attached at a high temperature are essential, which complicates operation. . The product gas contains a large amount of inorganic gases such as nitrogen, oxygen, carbon monoxide, carbon dioxide, and water vapor, and the recovery equipment is enlarged in order to separate and recover 1,3-butadiene. There is a drawback of doing. In addition, since the oxide catalyst containing molybdenum has a relatively low melting point, there is a problem that in the process of treating the catalyst to which carbon is attached at a high temperature, sintering is caused by heat and the activity is likely to be lowered.

  As a result of diligent studies to solve the above problems, the present inventor has found that a catalyst hopper, a downflow reactor, a gas-solid separator, and a catalyst regenerator are used to convert n-butene to butadiene by fluid catalytic oxidative dehydrogenation. The present invention has been completed by finding an apparatus that can be stably manufactured in a series of steady operations without unsteady operations.

That is, the present invention is as follows.
[1] An apparatus for producing butadiene from n-butene by fluid catalytic oxidative dehydrogenation reaction, comprising a catalyst hopper, a downflow reactor, a gas-solid separator, and a catalyst regenerator.
[2] An apparatus for producing butadiene according to [1], comprising a cyclone for separating catalyst particles from a reaction gas separated by a gas-solid separator and a stripper for separating a gas entrained from the catalyst separated by the gas-solid separator. .

  The present invention provides an apparatus capable of stably producing 1,3-butadiene from n-butene in a series of steady operations without involving unsteady operations. Furthermore, since the raw material to be supplied is mainly hydrocarbons containing n-butene, the amount of inorganic gas such as nitrogen can be greatly reduced, so that the equipment can be made compact and efficient 1,3- It is an apparatus that can also recover butadiene.

It is the schematic showing the one aspect | mode of the apparatus which manufactures the butadiene of this embodiment. It is the schematic showing another aspect of the apparatus which manufactures the butadiene of this embodiment. It is a flow figure showing one mode of a manufacturing method of butadiene. It is a flowchart showing another aspect of the manufacturing method of butadiene.

  Hereinafter, a mode for carrying out the present invention (hereinafter also referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[Equipment for producing butadiene]
The apparatus for producing butadiene of the present invention (fluid catalytic oxidation dehydrogenation reactor) has a catalyst hopper, a downflow reactor, a gas-solid separator, and a catalyst regenerator (see FIG. 1). In addition, it is preferable to install a cyclone for separating the catalyst from the reaction gas in the downstream of the gas-solid separator and to install a stripper between the gas-solid separator and the catalyst regenerator (see FIG. 2).

  Production of 1,3-butadiene from n-butene using the apparatus of the present invention can be carried out as follows.

  A catalyst is supplied from a catalyst hopper to a downflow reactor and mixed with a hydrocarbon gas containing n-butene as a raw material to cause a reaction. The reacted gas is separated from the catalyst in a gas-solid separator and is led to a rapid cooling step and an absorption recovery step, and 1,3-butadiene is recovered by a known technique. Further, the catalyst separated in the gas-solid separator is introduced into the catalyst regenerator, and is oxidized by a gas containing oxygen to regenerate the catalyst. The regenerated catalyst is supplied to a catalyst hopper through a pipe. By continuously operating the catalyst circulation and the reaction with n-butene, it is possible to stably produce 1,3-butadiene from n-butene.

  In addition, a cyclone is installed in the downstream of the gas-solid separator, and after further separating the catalyst particles in the cyclone from the reaction gas separated from the catalyst, it is led to a rapid cooling process and an absorption recovery process to recover 1,3-butadiene. This is also a preferred device combination. In addition, a stripper is installed between the gas-solid separator and the catalyst regenerator, and after separating the gas containing organic compounds accompanying the reaction gas and the catalyst separated by the gas-solid separator, the gas is introduced into the catalyst regenerator and oxygen It is also a preferable combination of the apparatuses to regenerate the catalyst by oxidizing with a gas containing. The stripped gas can be introduced into a system that recovers 1,3-butadiene or combusted as an exhaust gas. After the catalyst recovered by the cyclone installed in the downstream of the gas-solid separator is sent to the stripper or the catalyst regenerator together with the catalyst separated in the gas-solid separator, the catalyst is regenerated by oxidizing with a gas containing oxygen, Supply to catalyst hopper through piping. The combination of apparatuses that continuously perform the catalyst circulation operation makes it possible to more stably produce 1,3-butadiene from n-butene.

  In addition to producing 1,3-butadiene from n-butene, this production apparatus produces isoprene from isopentene, isopentane, methacrolein from isobutene, acrolein from propylene, and acrylonitrile from propylene and ammonia. Manufacture is also possible.

  The catalyst hopper preferably has a structure capable of maintaining the temperature of the catalyst at a temperature of 400 to 600 ° C.

  By supplying an inert gas such as nitrogen gas and fluidizing the inside of the hopper, the catalyst temperature can be made uniform and supplied to the downflow reactor stably.

  The reaction temperature in the downflow reactor is preferably 300 to 600 ° C., more preferably 350 to 550 ° C., and the catalyst / n-butene ratio (by weight) is preferably 10 to 500, and more Preferably it is 20-300, More preferably, it is 30-200, The residence time of n-butene in a downflow type | mold reactor becomes like this. Preferably it is 0.1-5.0 second, More preferably, it is 0.2-4 0.0 seconds, and more preferably 0.3 to 3.0 seconds. The reaction pressure is preferably 0 to 500 kPa / G, more preferably 10 to 400 kPa / G, and still more preferably 20 to 300 kPa / G. It is preferable to operate the apparatus other than the reactor at a pressure corresponding to this pressure.

  A hydrocarbon gas containing n-butene (1-butene, 2-butene) is used as the raw material, but only 1-butene, only 2-butene, or a mixture thereof may be used. The raw material n-butene is preferably gasified using a gasifier having a heating section such as steam or a heat transfer coil, and then supplied to the reactor. The raw material n-butene does not need to have a particularly high purity, and any mixture or industrial grade can be used. For example, a residual component (raffinate-1) extracted from 1,3-butadiene from a C4 fraction by-produced by naphtha pyrolysis, a residual component extracted from isobutylene (raffinate-2), n-butane dehydrogenation reaction or oxidation N-butene obtained by dehydrogenation, n-butene obtained by dimerization of ethylene, and n-butene by-produced in the catalytic conversion reaction of ethylene obtained by ethane pyrolysis or ethanol dehydration are used. be able to. Examples of ethanol include ethanol obtained by hydration of ethylene, biomass ethanol, and the like. For the latter, ethanol obtained from fermentation of sugarcane, corn, etc., and ethanol obtained from woody resources such as waste wood, thinned wood, rice straw, and crops are applicable.

  The hydrocarbon gas containing n-butene is present in a small amount of ethylene, propylene, pentene, hexene, heptene, octene, nonene, etc., acetylenes such as acetylene, methylacetylene, ethylacetylene, vinylacetylene, and butadiene. May be.

  The gas-solid separator is an apparatus that separates the catalyst and the reaction gas, and is preferably an equipment that separates the gas-solid on the principle of a cyclone.

The catalyst separated by the gas-solid separator is introduced into the catalyst regenerator, but it is introduced into the catalyst regenerator after separating the gas containing the accompanying organic compounds in a stripper installed between the gas-solid separator and the catalyst regenerator. It is also a preferred combination of devices. The stripper is preferably operated at a temperature of 200-600 ° C, more preferably 250-550 ° C. Further, if the residence time of the catalyst in the stripper is preferably 0.1 to 10 minutes, a sufficient stripping effect can be obtained. The flow rate of the stripping gas is preferably 0.05 to 1.0 m / second, more preferably 0.1 to 0.8 m / second, and still more preferably 0.2 to 0.6 m / second. As the stripping gas, an inert gas such as nitrogen, CO ₂ , water vapor, or argon can be used. Since the stripped gas contains a hydrocarbon compound, it is introduced into an exhaust gas incinerator and burned. Is preferred. A part of the burned gas can be supplied to the catalyst regenerator for use.

  The catalyst regenerator is preferably a fluidized bed type, and the catalyst regeneration temperature is preferably 300 to 600 ° C, more preferably 350 to 550 ° C, and further preferably 400 to 500 ° C. The oxygen concentration of the supply gas is preferably 0.5 to 25% by volume, more preferably 2.0 to 23% by volume, and still more preferably 5.0 to 21% by volume. Furthermore, the flow rate is preferably 0.05 to 1.0 m / sec, more preferably 0.1 to 0.8 m / sec, and still more preferably 0.2 to 0.6 m / sec. Moreover, the residence time of a catalyst becomes like this. Preferably it is 1-180 minutes, More preferably, it is 5-120 minutes, More preferably, it is 10-60 minutes. Within this range, the catalyst can be sufficiently regenerated. The regenerated catalyst is transferred to a catalyst hopper and subjected to a reaction for producing 1,3-butadiene.

  In the present invention, it is not necessary to basically supply molecular oxygen as a gas to the downflow reactor, but it can be supplied in a small amount. However, since oxygen accelerates the polymerization of 1,3-butadiene, in order to reduce the load of oxygen separation operation in the subsequent process or to eliminate the separation operation itself, Is preferably 1.0% by volume or less, more preferably 0.5% by volume or less, still more preferably 0.1% by volume or less, and most preferably 0.01% by volume or less.

  Patent Document 1 describes an example in which oxygen is supplied to a reactor together with n-butene as a raw material, and the reaction is performed in an upward flow, but the present invention is n which is a raw material supplied to the reactor. -It is possible to sharpen the residence time distribution for reacting hydrocarbons containing butene in the downflow, thus avoiding the effect of reduced selectivity due to the spread of residence time due to backmixing. .

  For the purpose of adjusting the residence time and LV of the downer part of the reactor, an inert gas such as nitrogen, saturated hydrocarbon, carbon dioxide, argon, water vapor or the like is in a volume ratio with respect to n-butene as a raw material, preferably 50% or less. More preferably, it can be supplied as 30% or less, more preferably 10% or less. The same applies to the entrainment of the inert gas such as nitrogen, saturated hydrocarbon, carbon dioxide, argon, and steam for pressurizing the catalyst hopper when the catalyst is supplied. As the saturated hydrocarbon, one or more gases selected from methane, ethane, propane, butane and the like can be used.

  As a result, the amount of gas supplied to the fluid catalytic oxidative dehydrogenation reactor can be reduced, and 1,3-butadiene can be recovered by a compact recovery facility.

〔catalyst〕
Examples of the catalyst used in the present invention include an oxide catalyst containing Mo supported on a support. 1,3-butadiene is produced from n-butene mainly by oxidative dehydrogenation utilizing lattice oxygen of the catalyst. To do. The catalyst is preferably an oxide containing Mo, Bi and Fe, more preferably represented by the following empirical formula.
_{Mo 12 Bi p Fe q A a} B b C c D d E e O x
(In the formula, A is at least one element selected from the group consisting of nickel and cobalt, B is at least one element selected from the group consisting of alkali metal elements, and C is magnesium, calcium, strontium, And at least one element selected from the group consisting of barium, zinc and manganese, D is at least one rare earth element, and E is at least one element selected from the group consisting of chromium, indium and gallium. , O is oxygen, and p, q, a, b, c, d, e, and x are the atomic ratios of bismuth, iron, A, B, C, D, E, and oxygen, respectively, to 12 atoms of molybdenum. 0.1 ≦ p ≦ 5.0, 0.5 ≦ q ≦ 8.0, 0 ≦ a ≦ 10, 0.02 ≦ b ≦ 2.0, 0 ≦ c ≦ 5.0, 0 ≦ d ≦ 5.0, 0 ≦ e ≦ 5.0 Ri, x is a number of oxygen atoms required to satisfy the valence requirements of the other elements present.)

  In the above formula, more preferable compositions are 0.2 ≦ p ≦ 3.0, 0.7 ≦ q ≦ 5.0, 1.0 ≦ a ≦ 9.0, 0.05 ≦ b ≦ 1.0, 1.0 ≦ c ≦ 4.0, 0.1 ≦ d ≦ 3.0, 0 ≦ e ≦ 4.0, and a more preferable composition is that at least B is selected from the group consisting of rubidium, potassium and cesium One element, C is magnesium, D is at least one element selected from the group consisting of cerium, lanthanum, praseodymium, neodymium, and yttrium, and 0.3 ≦ p ≦ 2.0, 1 0.0 ≦ q ≦ 3.0, 2.0 ≦ a ≦ 8.0, 0.1 ≦ b ≦ 0.5, 1.5 ≦ c ≦ 3.5, 0.2 ≦ d ≦ 2.0, 0 <= E <= 3.0.

  The carrier is preferably silica, alumina, titania or zirconia, more preferably silica. Silica is an inert carrier compared to other carriers, and has a good binding action with the catalyst without reducing the activity and selectivity of the catalyst with respect to the target product. In addition, by supporting the oxide on the support, physical properties suitable for fluidized bed reaction such as particle shape / size / distribution, fluidity, and mechanical strength can be imparted. The ratio of the carrier is 30 to 70% by mass, preferably 40 to 60% by mass, based on the total of the carrier and the oxide.

(Catalyst production method)
A supported catalyst containing an oxide containing Mo, Bi and Fe is obtained by a known method, for example, a first step of preparing a raw slurry, a second step of spray drying the raw slurry, and a second step. The obtained dried product can be obtained by a method including a third step.

  In the first step, a catalyst raw material is prepared to obtain a raw material slurry, but molybdenum, bismuth, iron, nickel, cobalt, alkali metal elements, magnesium, calcium, strontium, barium, zinc, manganese, rare earth elements, chromium, indium Examples of the element source of each element of gallium include ammonium salts, nitrates, hydrochlorides, sulfates, and organic acid salts that are soluble in water or nitric acid. In particular, ammonium salts are preferable as the molybdenum source, bismuth, iron, nickel, alkali elements, magnesium, zinc, manganese, and rare earth elements, and nitrates are preferable as the element sources of each element. As described above, oxides such as silica, alumina, titania and zirconia can be used as the oxide carrier, but silica is preferably used as the carrier and silica sol is preferable as the silica source. Regarding the impurities of the silica sol, a silica sol containing 0.04 atom or less of aluminum per 100 atoms of silicon is preferably used, and more preferably a silica sol containing 0.02 atom or less of aluminum per 100 atoms of silicon is used. The raw material slurry is prepared by adding ammonium salt of molybdenum dissolved in water to silica sol, and then adding nitrates of each element of bismuth, rare earth elements, iron, nickel, magnesium, zinc, manganese and alkaline elements to water or nitric acid. This can be done by adding a solution dissolved in an aqueous solution. In this way, a raw slurry can be prepared. At that time, the order of the addition can be changed.

  In the second step, the raw material slurry obtained in the first step is spray-dried to obtain spherical particles. The atomization of the raw material slurry can be performed by a method such as a centrifugal method, a two-fluid nozzle method, and a high-pressure nozzle method which are usually carried out industrially. Next, the obtained particles are dried, and it is preferable to use air heated by steam, an electric heater or the like as a drying heat source. The temperature at the dryer inlet is 100 to 400 ° C, preferably 150 to 300 ° C.

  In the third step, the desired catalyst is obtained by calcining the dried particles obtained in the second step. The dried particles are preferably calcined at 150 to 500 ° C. as necessary, and then at a temperature range of 500 to 700 ° C. for 1 to 20 hours. Firing can be performed using a firing furnace such as a rotary furnace, a tunnel furnace, or a muffle furnace. The average particle diameter of the catalyst is in the range of 40 to 70 μm, preferably 50 to 60 μm, and 90% by mass or more of the catalyst particles are preferably distributed in the range of 10 to 150 μm.

[Production method of butadiene]
Next, a method for producing butadiene according to this embodiment will be described. 3 and 4 are flow charts showing aspects of the method for producing butadiene.

  In the butadiene production method of the present embodiment, a butadiene is produced by a supply step of supplying a hydrocarbon gas containing a catalyst and n-butene to a reactor, and a catalytic oxidative dehydrogenation reaction using the catalyst in the reactor. A first separation step for separating the reaction step, the gas phase containing the produced butadiene, and the catalyst; a regeneration step for regenerating the separated catalyst using an oxygen-containing gas; And a refeeding step of refeeding the catalyst to the reactor.

  According to the butadiene production method of the present embodiment, the oxygen-containing gas that can be used as the oxygen source for the catalytic oxidative dehydrogenation reaction can be obtained by effectively using the oxygen constituting the catalyst as the oxygen source for the catalytic oxidative dehydrogenation reaction. The amount of use can be reduced, and the subsequent purification efficiency of butadiene can be further improved. Further, by continuously performing the catalyst circulation and the reaction with n-butene, it is possible to stably produce 1,3-butadiene from n-butene.

  It is preferable that the manufacturing method of butadiene of this embodiment has a heating process which heats the catalyst supplied in a reactor. Further, in the reaction step, it is preferable to perform a catalytic oxidative dehydrogenation reaction using a heated catalyst.

  Moreover, it is preferable that the manufacturing method of the butadiene of this embodiment has a 2nd isolation | separation process which isolate | separates a catalyst and oxygen-containing gas after a regeneration process.

  Furthermore, the butadiene production method of the present embodiment preferably has a third separation step of further separating the catalyst that can be contained in the gas phase separated in the first separation step and butadiene. In addition, the butadiene production method of the present embodiment is a fourth separation that further separates the catalyst from the butadiene accompanying the catalyst separated in the first separation step and, if necessary, the third separation step. It is preferable to have a process.

  Although the said manufacturing method can be implemented with the manufacturing apparatus mentioned above, the structure of an apparatus is not limited to this. Hereafter, each process of a manufacturing method and the structure of an apparatus are linked | related and demonstrated. First, a hydrocarbon gas containing a catalyst and n-butene is supplied to the reactor using a catalyst hopper that supplies the catalyst to the downflow reactor and a hydrocarbon gas supplier (supplying step). Next, butadiene is produced from n-butene by a fluid catalytic oxidative dehydrogenation reaction using a catalyst in a downflow reactor (reaction step). Further, the gas phase containing butadiene flowing out of the downflow reactor and the catalyst are separated using a gas-solid separator (first separation step). Next, the catalyst separated by the gas-solid separator is regenerated using a catalyst regenerator (regeneration step). Finally, the regenerated catalyst is supplied to the catalyst hopper using a supply mechanism (re-supply process). By this series of cycles, butadiene can be stably produced from n-butene in a series of steady operations without involving any unsteady operations. In addition, since the raw material to be supplied is mainly hydrocarbons containing n-butene, the amount of gas such as nitrogen can be greatly reduced, so that separation of the resulting butadiene and other gases becomes easier and equipment It is also possible to make it more compact.

  In addition, according to the production method of the present embodiment, in addition to producing 1,3-butadiene from n-butene, it is also possible to produce isoprene using isopentene as a raw material, and using isobutene as a raw material. Methacrolein can be produced, acrolein can be produced from propylene as a raw material, and acrylonitrile can be produced from propylene and ammonia as raw materials.

  The apparatus for producing butadiene of the present invention comprises a catalyst hopper, a downflow reactor, a gas-solid separator, and a catalyst regenerator, and produces 1,3-butadiene from n-butene by fluid catalytic oxidative dehydrogenation. As an industrial applicability.

Claims (2)

  An apparatus for producing butadiene from n-butene by fluid catalytic oxidative dehydrogenation reaction, comprising a catalyst hopper, a downflow reactor, a gas-solid separator, and a catalyst regenerator.   The apparatus for producing butadiene according to claim 1, further comprising a cyclone for separating the catalyst particles from the reaction gas separated by the gas-solid separator, and a stripper for separating the accompanying gas from the catalyst separated by the gas-solid separator.

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