Patent Description:
<NUM>,<NUM>-butadiene is an intermediate of petroleum chemical products, and demands for <NUM>,<NUM>-butadiene and the value thereof are gradually increasing globally. The <NUM>,<NUM>-butadiene has been prepared by using naphtha cracking, the direct dehydrogenation reaction of butene, the oxidative dehydrogenation reaction of butene, and the like.

The oxidative dehydrogenation reaction of butene is a reaction in which butene and oxygen react with each other in the presence of a metal oxide catalyst to produce <NUM>,<NUM>-butadiene and water, and has a thermodynamically very favorable advantage because stable water is produced. Further, since the oxidative dehydrogenation reaction of butene is an exothermic reaction unlike the direct dehydrogenation reaction of butene, <NUM>,<NUM>-butadiene may be obtained at high yield even at low reaction temperature as compared to the direct dehydrogenation reaction, and the oxidative dehydrogenation reaction of butene may become an effective single production process capable of satisfying the demands for <NUM>,<NUM>-butadiene because an additional heat supply is not required.

The metal oxide catalyst is generally synthesized by a precipitation method. In particular, when a ferrite-based catalyst is used as a metal oxide catalyst, the ferrite-based catalyst generates heats, thereby increasing the COx selectivity and decreasing the butadiene selectivity. Accordingly, studies on controlling exotherm and simultaneously controlling the hot spot movement of the catalyst have been continuously conducted. <CIT> relates to a process for preparing butadiene from n-butenes, in which the formation of butadiene peroxides from butadiene in the work-up of the product gas mixture from the oxidative dehydrogenation is effectively prevented. <CIT> discloses a a method of producing a conjugated diene, capable of preventing the accumulation of a carbon component such as coke in a catalyst disposed in a reactor to enable a stable and continuous operation of a plant for a long period of time.

The present specification provides a method for filling a catalyst and a method for preparing butadiene using the same.

The present invention as defined in claim <NUM> is a method for filling a catalyst for an oxidative dehydrogenation reaction of butene, the method comprising:.

Another aspect of the present invention is defined in claim <NUM> and provides a method for preparing butadiene, the method comprising:.

A third aspect of the present invention is defined in claim <NUM> and provides a catalyst reactor which is filled with a mixture of a ferrite-based catalyst molded article and diluent material particles wherein the ferrite-based catalyst is a zinc ferrite catalyst, and the diluent material particles are aluminum oxide (a-Al<NUM>O<NUM>), and wherein in the top of the catalyst reactor where a reactant of the oxidative dehydrogenation reaction flows in, and thus reacts in the presence of the catalyst. , the ratio of the weight of the ferrite-based catalyst molded article to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles is <NUM> wt% to <NUM> wt%.

A method for filling a catalyst according to an exemplary embodiment of the present specification may simultaneously control the hot spot movement rate of a catalyst within a range capable of controlling exotherm caused by a catalyst reaction during an oxidative dehydrogenation reaction of butene, thereby securing the stability of the reaction and reducing costs caused by an increase in reaction temperature.

In addition, the hot spot movement rate may be decreased by controlling the concentration of a catalyst as compared to a diluent material in a section of a catalyst reactor where a reaction starts.

In the present specification, the 'yield (%)' is defined as a value obtained by dividing the weight of <NUM>,<NUM>-butadiene as a product of an oxidative dehydrogenation reaction by the weight of butene (BE) as a raw material. For example, the yield may be represented by the following equation. <MAT> In the present specification, the 'conversion rate (%)' refers to a rate at which a reactant is converted into a product, and for example, the conversion rate of butene may be defined by the following equation.

In the present specification, the 'selectivity (%)' is defined as a value obtained by dividing the change amount of butadiene by the change amount of butene. For example, the selectivity may be represented by the following equation.

In the present specification, the 'hot spot of a catalyst' means a place where the temperature on the catalyst is the highest in the reactor.

An exemplary embodiment of the present specification comprises: (A) mixing a ferrite-based catalyst molded article with diluent material particles; and (B) filling a catalyst reactor with a mixture of the ferrite-based catalyst molded article and the diluent material particles, wherein the ferrite-based catalyst is a zinc ferrite catalyst, and the diluent material particles are aluminum oxide (α-Al<NUM>O<NUM>), and wherein a section of the catalyst reactor where the reaction starts is filled, such that the ratio of the weight of the ferrite-based catalyst molded article as compared to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles is <NUM> wt% to <NUM> wt%.

Further, an exemplary embodiment of the present specification provides a method for filling a catalyst, the method comprising filling at least a partial section in the catalyst reactor, such that the ratio of the weight of the ferrite-based catalyst molded article to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles is <NUM> wt% to <NUM> wt%.

A ferrite-based catalyst may be used in an oxidative dehydrogenation reaction of butene. The oxidative dehydrogenation reaction is an exothermic reaction, and an increase in COx selectivity and a decrease in butadiene selectivity occur due to the exotherm of the ferrite-based catalyst. Accordingly, a technology of controlling exotherm by diluting the ferrite-based catalyst with an inactive material is known.

However, the related art has an effect of decreasing the amount of heat generated by a catalyst reaction, but as the reaction time elapses, there occurs a phenomenon in which a hot spot of the catalyst moves to the rear side of the reactor in a longitudinal direction, and the reaction temperature needs to be increased to maintain the position of the hot spot.

The movement of the hot spot of the catalyst is associated with the inactivity of the catalyst, and there is a problem in that the increase in reaction temperature causes an increase in process costs.

Accordingly, the present inventors could adjust the dilution ratio of a catalyst molded article in a catalyst reactor by using the catalyst reactor which is filled by mixing diluent material particles with the catalyst molded article instead of diluting the catalyst itself. As a result, the present inventors secured the stability of operation by simultaneously controlling the hot spot movement rate of a catalyst within a range capable of controlling exotherm caused by a catalyst reaction, and could reduce costs because the reaction temperature does not need to be increased. Further, the present inventors could reduce the hot spot movement rate by limiting the concentration of the catalyst in a section where an oxidative dehydrogenation reaction starts.

In addition, when a catalyst itself is diluted with a binder material and the like, the catalyst itself is embedded in the molded article, thereby significantly reducing a catalyst area in which an actual reactant may be brought into contact with the catalyst. However, since the method for filling a catalyst according to the present invention uses a catalyst molded article itself as it is, the surface of the catalyst introduced may be totally brought into contact with the reactant. Accordingly, the dilution ratio in the catalyst reactor may be easily adjusted to control the hot spot movement rate.

The catalyst reactor may be filled with a ferrite-based catalyst molded article and diluent material particles, such that the dilution ratios of the top and the bottom in the catalyst reactor are different from each other.

The section where a reaction in the catalyst reactor starts is filled, such that the ratio of the weight of the ferrite-based catalyst molded article to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles is <NUM> wt% to <NUM> wt%, and the entire section in the catalyst reactor may be filled, such that the ratio of the weight of the ferrite-based catalyst molded article as compared to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles is <NUM> wt% to <NUM> wt%. As described above, according to the invention, the hot spot movement rate may be decreased by controlling the concentration of a catalyst as compared to a diluent material in a section of the catalyst reactor where a reaction starts.

The section of the catalyst reactor where the reaction starts may mean the top of the reactor, that is, a section where a reactant of the oxidative dehydrogenation reaction flows in, and thus reacts in the presence of the catalyst. A section where the reaction terminates may mean the bottom of the reactor, that is, a bottom portion where the reactant of the oxidative dehydrogenation reaction has been flown down from the top after the reaction is completed.

According to an exemplary embodiment of the present specification, the entire section of the catalyst reactor may mean a region from a section of a catalyst reactor where a reaction starts to a section thereof where the reaction terminates, and specifically, may mean a region where the catalyst in the reactor is filled.

According to an exemplary embodiment of the present specification, from the section of the catalyst reactor where the reaction starts to the section thereof where the reaction terminates, the ratio of the weight of the ferrite-based catalyst molded article in the entire section may be uniform.

According to an exemplary embodiment of the present specification, the fact that the ratio of the weight of the ferrite-based catalyst molded article is made to be uniform may mean that the ratio of the weight of the ferrite-based catalyst molded article measured in any region in the catalyst reactor is the same.

According to an exemplary embodiment of the present specification, the ferrite-based catalyst may mean a ferrite-based catalyst prepared by a co-precipitation method. The co-precipitation method may comprise: co-precipitating a metal precursor and a basic aqueous solution; filtering a precipitate; drying the precipitate; and firing the precipitate.

The ferrite-based catalyst is a zinc ferrite catalyst.

According to an exemplary embodiment of the present specification, the metal precursor may be a zinc precursor, a ferrite precursor, or the like, but is not limited thereto as long as the metal precursor is typically used. Further, the metal precursor may be one or more selected from the group consisting of nitrate, ammonium salt, sulfate, and chloride, or a hydrate thereof.

According to an exemplary embodiment of the present specification, the ferrite-based catalyst may be prepared by a co-precipitation method of bringing a zinc precursor and a ferrite-based precursor into contact with a basic aqueous solution.

According to an exemplary embodiment of the present specification, the zinc precursor may be zinc chloride (ZnCl<NUM>).

According to an exemplary embodiment of the present specification, the ferrite-based precursor may be ferric chloride hydrate (FeCl<NUM>·<NUM><NUM>O).

According to an exemplary embodiment of the present specification, a pH of the basic aqueous solution may be <NUM> to <NUM>. Specifically, a pH of the basic aqueous solution may be more than <NUM> and <NUM> or less. More specifically, a pH of the basic aqueous solution may be <NUM> to <NUM>. When the pH of the basic aqueous solution satisfies the above range, there is an effect of stably producing a metal composite catalyst.

According to an exemplary embodiment of the present specification, the basic aqueous solution may be one or more selected from the group consisting of potassium hydroxide, ammonium carbonate, ammonium bicarbonate, an aqueous sodium hydroxide solution, an aqueous sodium carbonate solution, and ammonium water. Preferably, the basic aqueous solution may be ammonia water.

According to an exemplary embodiment of the present specification, the drying of the precipitate may be performed before firing the precipitate after the precipitate is filtered and then subjected to a washing step.

According to an exemplary embodiment of the present specification, the drying of the precipitate may be performed in an oven at <NUM> to <NUM>.

According to an exemplary embodiment of the present specification, the firing of the precipitate may be a step of increasing the temperature up to <NUM> at a rate of <NUM>/min, and then firing the precipitate for <NUM> hours. The firing method may be a heat treatment method typically used in the art.

According to an exemplary embodiment of the present specification, the firing of the precipitate may be performed by injecting the air at <NUM>/min into a firing furnace.

According to an exemplary embodiment of the present specification, the ferrite-based catalyst may form the ferrite-based catalyst molded article by using an extruder. The ferrite-based catalyst molded article may be molded in the form of a pellet type, a ball type, or a hollow type.

According to an exemplary embodiment of the present specification, the pellet may have a diameter of <NUM> to <NUM>, and <NUM> to <NUM>. When the diameter of the pellet satisfies the above range, the exotherm of the catalyst may be controlled and the activity of the catalyst may be improved.

According to an exemplary embodiment of the present specification, a final ferrite-based catalyst molded article may be prepared by further comprising molding the ferrite-based catalyst into a pellet, and then sintering the ferrite-based catalyst.

According to the invention, the diluent material particle is aluminum oxide (α-Al<NUM>O<NUM>).

According to an exemplary embodiment of the present specification, the diluent material particle may be a ball type having a diameter of <NUM> to <NUM>, and a ball type having a diameter of <NUM> to <NUM>. When the diameter of the diluent material particles satisfies the above range, the catalyst may be diluted at a desired ratio without hindering the activity of the catalyst during the mixing of the catalyst molded article, so that it is possible to decrease the hot spot movement rate of the catalyst. The diluent material particle may be not only a ball type, and other various types.

According to an exemplary embodiment of the present specification, the step (A) may comprise mixing <NUM> cc to <NUM> cc of the catalyst molded article with <NUM> cc to <NUM> cc of the diluent material particles.

According to an exemplary embodiment of the present specification, when the content of the catalyst molded article and the diluent material particles is within the above range, at the time of filling the catalyst reactor with the catalyst molded article and the diluent material particles, the content may be adjusted, such that the ratio of the weight of the catalyst molded article to the total weight of the catalyst molded article mixed with the diluent material particles is <NUM> wt% to <NUM> wt%.

Another aspect of the invention provides a method for preparing butadiene according to claim <NUM>, the method comprising: filling a catalyst reactor with a catalyst according to the above-described method for filling a catalyst; and preparing butadiene by subjecting a raw material comprising butene to oxidative dehydrogenation reaction in the catalyst reactor.

According to an exemplary embodiment of the present specification, the hot spot movement rate of the catalyst of the oxidative dehydrogenation reaction may be <NUM> to <NUM>/hr, <NUM>/hr to <NUM>/hr, and <NUM>/hr or more and less than <NUM>/hr. The movement of the hot spot of the catalyst is associated with the inactivity of the catalyst, and the increase in reaction temperature may incur a problem in that an increase in process costs is caused. Accordingly, according to an exemplary embodiment of the present specification, when the hot spot movement rate of the catalyst of the oxidative dehydrogenation reaction satisfies the numerical range, it is possible to obtain an effect of reducing operation costs due to the low inactivity rate of the catalyst.

Further, another aspect of the invention is a catalyst reactor which is filled with a mixture of a ferrite-based catalyst molded article and diluent material particles, wherein the ferrite-based catalyst is a zinc ferrite catalyst, and the diluent material particles are aluminum oxide (a-Al<NUM>O<NUM>), and wherein in the top of the catalyst reactor where a reactant of the oxidative dehydrogenation reaction flows in, and thus reacts in the.

presence of the catalyst. , the ratio of the weight of the ferrite-based catalyst molded article to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles is <NUM> wt% to <NUM> wt%.

In particular, according to an exemplary embodiment of the present specification, in a section where a reaction in the catalyst reactor starts, the ratio of the weight of the ferrite-based catalyst molded article to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles is <NUM> wt% to <NUM> wt%, and in the entire section in the catalyst reactor, the ratio of the weight of the ferrite-based catalyst molded article to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles may be <NUM> wt% to <NUM> wt%. When the ratio of the weight of the catalyst molded article in the entire section of the catalyst reactor is within the above range, the hot spot movement rate of the catalyst may be decreased during the oxidative dehydrogenation reaction of butene.

Furthermore, another exemplary embodiment of the present specification provides a method for preparing butadiene, the method comprising preparing butadiene by subjecting a raw material comprising butene to oxidative dehydrogenation reaction in the above-described catalyst reactor.

According to an exemplary embodiment of the present specification, the preparing of the butadiene may use a reactant comprising a C4 mixture. The C4 mixture comprises one or more normal butenes selected from <NUM>-butene (trans-<NUM>-butene, cis-<NUM>-butene) and <NUM>-butene as an example, and selectively, may further comprise normal butane or C4 raffinate-<NUM>. The reactant may further comprise one or more selected from air, nitrogen, steam, and carbon dioxide as an example, and preferably, further comprises nitrogen and steam. As a specific example, the reactant may comprise the C4 mixture, oxygen, steam, and nitrogen at a mol ratio of <NUM> : <NUM> to <NUM> : <NUM> to <NUM> : <NUM> to <NUM> or <NUM> : <NUM> to <NUM> : <NUM> to <NUM> : <NUM> to <NUM>. Furthermore, the method for preparing butadiene according to an exemplary embodiment of the present specification has an advantage in that the reaction efficiency is excellent and waste water is generated in a small amount even though steam is used in a small amount of <NUM> to <NUM> or <NUM> to <NUM> mol based on <NUM> mol of the C4 mixture, and ultimately provides an effect of reducing not only waste water treatment costs, but also energy consumed for the process. The oxidative dehydrogenation reaction may be performed, for example, at a reaction temperature of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>, and within this range, the reaction efficiency is excellent without significantly increasing the energy costs, so that <NUM>,<NUM>-butadiene may be provided with high productivity.

According to an exemplary embodiment of the present specification, the preparing of the butadiene is performed under conditions of a reaction temperature of <NUM> and a gas hourly space velocity (GHSV) of <NUM>-<NUM> in a single reactor, and the reactant may comprise the C4 mixture : oxygen : steam : nitrogen at a mol ratio of <NUM> : <NUM> : <NUM> : <NUM>.

As described above, the method for filling a catalyst according to an exemplary embodiment of the present specification may fill a catalyst by mixing a ferrite-based catalyst molded article used for an oxidative dehydrogenation reaction with diluent material particles and constantly adjust the ratio of the weight of the catalyst molded article to the total weight of the catalyst molded article mixed with the diluent material particles in the entire section of the catalyst reactor, thereby controlling exotherm and simultaneously decreasing the hot spot movement rate of the catalyst.

Hereinafter, the present specification will be described in detail with reference to Examples for specifically describing the present specification. However, the Examples according to the present specification may be modified in various forms, and it is not interpreted that the scope of the present specification is limited to the Examples described below in detail. The Examples of the present specification are provided to more completely explain the present specification to a person with ordinary skill in the art.

A metal precursor solution was prepared by dissolving <NUM> of zinc chloride (ZnCl<NUM>) and <NUM> of ferric chloride (FeCl<NUM>) in <NUM> of distilled water. In this case, for a mol ratio of the metal components comprised in the metal precursor solution, Zn : Fe = <NUM> : <NUM>. An aqueous ammonia solution was added dropwise to the prepared aqueous metal precursor solution such that the pH was <NUM>, and the resulting mixture was stirred for <NUM> hour and co-precipitated. Thereafter, a co-precipitate was obtained by filtering the co-precipitation solution under reduced pressure, and after the co-precipitate was dried at <NUM> for <NUM> hours, and then the temperature was increased up to <NUM> from <NUM> at a warming rate of <NUM>/min under the air atmosphere, a zinc-iron oxide (ZnFe<NUM>O<NUM>) powder having a spinel structure was prepared by maintaining the temperature for <NUM> hours.

After the prepared metal oxide powder was ground to <NUM> to <NUM>, a mixture of isopropyl alcohol with water as a liquid binder was introduced into the powder, and then the resulting product was uniformly kneaded by using a kneader, and the kneaded product was molded into a cylindrical pellet having a diameter of <NUM> to <NUM>, a circular cross section, and a height of <NUM> to <NUM> by using an extrusion molding machine. The molded pellet was dried at <NUM> for <NUM> hours and heat-treated at <NUM> for <NUM> hours.

<NUM> cc of an α-Al<NUM>O<NUM> ball having a diameter of <NUM> to <NUM> was mixed with <NUM> cc of the ferrite-based catalyst molded article prepared in Preparation Example <NUM>, and a reactor was filled with the mixture, such that the ratio of the catalyst molded article was <NUM> wt% in the entire section of the reactor.

The reactor was filled with <NUM> cc of the ferrite-based catalyst molded article prepared in Preparation Example <NUM> and <NUM> cc of the α-Al<NUM>O<NUM> ball having a diameter of <NUM> to <NUM> by varying the ratio of the top and the bottom of the reactor as in the following Table <NUM>. In this case, the ratio of the catalyst in a section (top) of the reactor where the reaction started was <NUM> wt%.

After <NUM>) the preparation of the catalyst for an oxidative dehydrogenation reaction in Preparation Example <NUM>, <NUM> of a commercially available alumina silicate support was coated with <NUM> of the catalyst to mold the resulting product such that the ratio of the catalyst to the total weight of the ferrite-based catalyst molded article was <NUM> wt%.

A reactor was filled with <NUM> cc of the obtained ferrite-based catalyst molded article without any additional dilution.

The entire section of the reactor was filled with the catalyst molded article without mixing <NUM> cc of the ferrite-based catalyst molded article prepared in Preparation Example <NUM> with a diluent material.

The results of subjecting a raw material comprising butene to oxidative dehydrogenation reaction in each of the reactors in Examples <NUM> to <NUM> and Comparative Examples <NUM> and <NUM>, and measuring the hot spot movement rate, the conversion rate of butene, the butadiene selectivity, the COx selectivity, and the change in temperature of the hot spot are shown in the following Table <NUM>.

The preparing of the butadiene by the oxidative dehydrogenation reaction was performed under conditions of a reaction temperature of <NUM> and a gas hourly space velocity (GHSV) of <NUM>-<NUM> in a single reactor, and the reactant comprised the C4 mixture : oxygen : steam : nitrogen at a mol ratio of <NUM> : <NUM> : <NUM> : <NUM>.

According to Table <NUM>, it can be confirmed that in the case of an oxidative dehydrogenation reaction of butene in a catalyst reactor which is filled with a mixture of the catalyst molded article with the diluent material particles according to Example <NUM>, the hot spot movement rate is decreased.

When Example <NUM> is compared with Comparative Example <NUM>, it can be confirmed that in Example <NUM> in which the catalyst molded article is used as it is and the ratio of the catalyst of the reactor is adjusted by using the diluent material particles, the hot spot movement rate is decreased to <NUM>/<NUM> or less, and the conversion rate of butene is improved as compared to Comparative Example <NUM> in which a catalyst molded article diluted by coating a support with the catalyst itself is used.

In addition, when Example <NUM> is compared with Comparative Example <NUM>, it can be confirmed that in Example <NUM> in which the catalyst molded article is used as it is and the ratio of the catalyst of the reactor is adjusted by using the diluent material particles, the hot spot movement rate is decreased to <NUM>/<NUM> or less as compared to Comparative Example <NUM> in which a catalyst which is not mixed with a diluent material is used.

When Example <NUM> is compared with Reference Examples <NUM> and <NUM>, it can be seen that when the reactor is filled such that the ratio of the catalyst in the section where the reaction starts is <NUM> wt% to <NUM> wt%, a better effect can be obtained.

Claim 1:
A method for filling a catalyst for an oxidative dehydrogenation reaction of butene, the method comprising:
(A) mixing a ferrite-based catalyst molded article with diluent material particles; and
(B) filling a catalyst reactor with a mixture of the ferrite-based catalyst molded article and the diluent material particles,
wherein the ferrite-based catalyst is a zinc ferrite catalyst, and
the diluent material particles are aluminum oxide (α-Al<NUM>O<NUM>), and
wherein a section of the catalyst reactor where the reaction starts is filled, such that the ratio of the weight of the ferrite-based catalyst molded article as compared to the sum of the weights of the ferrite-based catalyst molded article and the diluent material particles is <NUM> wt% to <NUM> wt%.