WO2021006245A1

WO2021006245A1 - Method for producing ethylene, and method for producing polymer

Info

Publication number: WO2021006245A1
Application number: PCT/JP2020/026426
Authority: WO
Inventors: 周知佐藤; 憲男沼田
Original assignee: 積水化学工業株式会社
Priority date: 2019-07-05
Filing date: 2020-07-06
Publication date: 2021-01-14
Also published as: JPWO2021006245A1

Abstract

A method for producing ethylene according to the present invention includes: an ethylene production step for obtaining an ethylene-containing product that contains ethylene from raw ethanol containing waste-derived ethanol; and at least one of a first purification step for purifying the raw ethanol before the ethylene production step and a second purification step for purifying the ethylene-containing product after the ethylene production step.

Description

Ethylene production method and polymer production method

The present invention relates to a method for producing ethylene from raw material ethanol containing ethanol derived from waste, and a method for producing a polymer using ethylene obtained by the production method as a raw material.

Conventionally, ethylene is produced from naphtha, crude oil, natural gas, etc. as raw materials. Ethylene is required to have high purity due to the polymerization reaction and the quality requirements of the polymer. For example, in ethylene polymerization by the high pressure method, ethylene having a purity of 99.9% or more is used. Therefore, conventionally, a technique of purifying a raw material olefin such as ethylene and then polymerizing the raw material olefin is known.

For example, in Patent Document 1, a raw material olefin containing carbon dioxide as an impurity is brought into contact with a hybrid adsorbent composed of a mixture of active alumina and zeolite to purify the raw material olefin, and then the purified olefin is brought into contact with a transition metal complex catalyst. Described is an invention relating to a method for polymerizing an olefin, which comprises polymerizing the mixture.
According to Patent Document 1, a metallocene catalyst having few drawbacks of the conventionally used Ziegler-Natta catalyst has been developed, the metallocene catalyst is extremely sensitive to impurities in the raw material olefin, and naphtha and crude oil. , Industrial ethylene obtained by using natural gas, etc. contains carbon dioxide of about several ppm (volume) to several hundred ppm (volume), and carbon dioxide has an adverse effect as a catalytic poison in the polymerization of metallocene catalysts. It is stated to bring. The invention described in Patent Document 1 is an economical, simple and efficient removal of carbon dioxide using the hybrid adsorbent, thereby performing impurities in olefin polymerization using a transition metal complex catalyst such as a metallocene catalyst. It is described that the decrease in catalytic activity due to the above can be sufficiently suppressed, and the polymer can be industrially stably produced with high productivity.

In recent years, the importance of carbon neutrality and carbon cycle has been discussed, and bioethanol produced from sugar cane, etc., ethanol derived from waste, etc. are being studied. Of these, bioethanol has problems from the viewpoint of food competition and biodiversity, and waste-derived ethanol is drawing attention.

JP-A-2017-137464

However, when ethylene is produced using ethanol derived from waste as a raw material and ethylene, and then a polymer is produced using the ethylene, the polymerization reaction proceeds appropriately because the origin is different from that of conventional industrial ethylene. It was also found that the quality of the polymer may not be sufficient.

Therefore, the present invention provides a method for producing ethylene in which the polymerization reaction of ethylene proceeds appropriately and the quality of the obtained polymer is good even when ethylene is produced using ethanol derived from waste as a raw material. Is an issue.

The gist of the present invention is the following [1] to [8].
[1] An ethylene production step of obtaining an ethylene-containing product containing ethylene from raw material ethanol containing ethanol derived from waste, and
It comprises at least one of a first purification step of purifying the raw material ethanol prior to the ethylene production step and a second purification step of purifying the ethylene-containing product after the ethylene production step.
Ethylene production method.
[2] The first purification step is carried out from the raw material ethanol by an aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms, an aliphatic saturated hydrocarbon having 3 to 14 carbon atoms, an alcohol having 3 to 10 carbon atoms, and carbon. The method for producing ethylene according to the above [1], which comprises removing at least one selected from the group consisting of the ethers of the number 3 to 10.
[3] The second purification step is carried out from the ethylene-containing product to an aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms, an aliphatic saturated hydrocarbon having 3 to 14 carbon atoms, and an alcohol having 3 to 10 carbon atoms. The method for producing ethylene according to the above [1] or [2], which comprises removing at least one selected from the group consisting of ether having 3 to 10 carbon atoms, carbon monoxide, and oxygen.
[4] The method for producing ethylene according to the above [2] or [3], wherein the aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms contains propylene.
[5] The production of ethylene according to any one of the above [2] to [4], wherein the aliphatic saturated hydrocarbon having 3 to 14 carbon atoms contains an aliphatic saturated hydrocarbon having 6 to 14 carbon atoms. Method.
[6] The method for producing ethylene according to any one of the above [2] to [5], wherein the alcohol having 3 to 10 carbon atoms contains 2-propanol.
[7] The method for producing ethylene according to any one of the above [2] to [6], wherein the ether having 3 to 10 carbon atoms contains dibutyl ether.
[8] A method for producing a polymer, which comprises a polymerization step of polymerizing a monomer containing ethylene produced by the method according to any one of the above [1] to [7] to obtain a polymer.

According to the present invention, even when ethylene is produced from ethanol derived from waste as a raw material, the polymerization reaction of ethylene proceeds favorably and the quality of the obtained polymer is good.

Hereinafter, the present invention will be described with reference to embodiments.
The present invention comprises an ethylene production step of obtaining an ethylene-containing product containing ethylene from a raw material ethanol containing ethanol derived from waste, a first purification step of purifying the raw material ethanol, and ethylene production before the ethylene production step. It comprises at least one of the second purification steps of purifying the ethylene-containing product after the step.
In the present invention, by performing the purification step before, after, or both of the ethylene production steps, the ethylene polymerization reaction proceeds appropriately even when ethanol derived from waste is used as a raw material, and the polymer The quality of the obtained polymer is improved, for example, the molecular weight of the polymer is sufficiently high.

Hereinafter, the present invention will be described in detail.
[Ingredient ethanol]
The raw material ethanol used as a raw material in the present invention contains ethanol derived from waste. Waste-derived ethanol is produced from waste-derived gas obtained by burning or thermally decomposing waste.
The waste may be industrial waste such as industrial solid waste, general waste such as urban solid waste (MSW), plastic waste, garbage, waste tires, biomass waste, food waste. , Building materials, wood, wood chips, fibers, papers and other flammable substances. Of these, municipal solid waste (MSW) is preferred.
The waste-derived gas is preferably converted to ethanol by either gas-utilizing microorganisms or metal catalysts.

The waste-derived gas is preferably a synthetic gas containing carbon monoxide and hydrogen. Hereinafter, an example in which the waste-derived gas is a synthetic gas will be described in detail. Syngas is subjected to a raw material gas generation step of producing a raw material gas by gasifying waste, and further, various pollutants, dust particles, impurities, unfavorable amounts of compounds, etc. are identified from the generated raw material gas. It can be obtained by performing a synthetic gas purification step of removing or reducing the substance of.

(Raw material gas generation process)
For gasification of waste in the raw material gas generation step, for example, a gasification furnace may be used. The gasification furnace is a furnace that burns (incompletely burns) a carbon source, and examples thereof include a shaft furnace, a kiln furnace, a fluidized bed furnace, a gasification reforming furnace, and a plasma gasification furnace. The temperature at which the waste is gasified into the raw material gas is not particularly limited, but is usually 100 to 2500 ° C, preferably 200 to 2100 ° C.

The raw material gas obtained by gasifying the waste may contain carbon monoxide and hydrogen, but may further contain carbon dioxide, oxygen and nitrogen. Further, the raw material gas may further contain components such as soot, tar, nitrogen compound, sulfur compound, phosphorus compound and organic compound. The raw material gas typically contains carbon monoxide in an amount of 0.1% by volume or more and 80% by volume or less, and hydrogen in an amount of 0.1% by volume or more and 80% by volume or less. Further, it is preferable that carbon dioxide is contained in an amount of 0.1% by volume or more and 70% by volume or less.

The raw material gas is carbon monoxide by performing heat treatment (commonly known as gasification) to burn (incompletely burn) the waste, that is, by partially oxidizing the waste, but there is no particular limitation, but 0. It is preferable that the gas is produced as a gas containing 1% by volume or more, preferably 10% by volume or more, and more preferably 20% by volume or more.

(Syngas purification process)
As described above, the raw material gas may be a synthetic gas by removing or reducing specific substances such as various pollutants, dust particles, impurities, and an unfavorable amount of compounds. When ethanol is obtained from synthetic gas by microbial fermentation, substances unfavorable for stable culture of microorganisms and unfavorable amounts of compounds are reduced or removed from the raw material gas, and the content of each component contained in the raw material gas is contained. Is preferably in a range suitable for stable culture of microorganisms. Also, when ethanol is obtained from synthetic gas using a metal catalyst, it is preferable to reduce or remove substances that inactivate the metal catalyst.

In the synthetic gas refining process, for example, a water content separator consisting of a gas chiller, a low temperature separation method (deep cooling method) separation device, a fine particle separation device for separating fine particles such as soot represented by various filters of cyclone and bag filter, Water-soluble impurity separation device such as scrubber, desulfurization device (sulfide separation device), membrane separation type separation device, deoxidizer, pressure swing adsorption type separation device (PSA), temperature swing adsorption type separation device (TSA) , Pressure-temperature swing adsorption type separation device (PTSA), separation device using activated carbon, deoxidizing catalyst, specifically, one or more of separation devices using copper catalyst or palladium catalyst, etc. It is advisable to purify the raw material gas by performing the treatment using the above to obtain a synthetic gas.

Further, when ethanol is obtained by microbial fermentation, it is preferable to reduce the concentration of carbon dioxide gas in the raw material gas. For example, a pressure swing adsorption type separator filled with a regenerated adsorbent containing zeolite can be used to adsorb the carbon dioxide gas in the synthetic gas to the regenerated adsorbent to reduce the carbon dioxide gas concentration in the synthetic gas. preferable.

As described above, the obtained synthetic gas may contain at least carbon monoxide and hydrogen as essential components, and may further contain carbon dioxide and nitrogen. The carbon monoxide concentration in the synthetic gas is usually 20% by volume or more and 80% by volume or less, preferably 25% by volume or more and 50% by volume, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen and nitrogen in the synthetic gas. By volume or less, more preferably 30% by volume or more and 45% by volume or less.
The hydrogen concentration in the synthetic gas is usually 10% by volume or more and 80% by volume or less, preferably 30% by volume or more and 55% by volume, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen and nitrogen in the synthetic gas. It is more preferably 30% by volume or more and 50% by volume or less.

The carbon dioxide concentration in the synthetic gas is not particularly limited, but is usually 0.1% by volume or more and 40% by volume or less, preferably 0, with respect to the total concentration of carbon dioxide, carbon dioxide, hydrogen and nitrogen in the synthetic gas. .3% by volume or more and 30% by volume or less. The carbon dioxide concentration is particularly preferably lowered when ethanol is produced by microbial fermentation, and from such a viewpoint, it is more preferably 0.5% by volume or more and 25% by volume or less.
The concentration of nitrogen in the synthetic gas is usually 40% by volume or less, preferably 1% by volume or more and 20% by volume or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen and nitrogen in the synthetic gas. More preferably, it is 5% by volume or more and 15% by volume or less.

The concentrations of carbon monoxide, carbon dioxide, hydrogen and nitrogen in the synthetic gas can be adjusted by appropriately changing the combustion conditions such as the type of waste, the gasification temperature in the raw material gas generation process, and the oxygen concentration of the supply gas during gasification. , Can be in a predetermined range.
For example, if you want to change the concentration of carbon monoxide or hydrogen, change to waste with a high ratio of hydrocarbons (carbon and hydrogen) such as waste plastic, and if you want to reduce the nitrogen concentration, change the oxygen concentration in the raw material gas generation process. There is a method of supplying high gas.
Further, at least one of the raw material gas and the synthetic gas may be appropriately adjusted in concentration of each component of carbon monoxide, carbon dioxide, hydrogen and nitrogen. For concentration adjustment, at least one of these components may be added to the raw material gas or the synthetic gas. The amount added is, for example, less than 50% by volume, preferably less than 30% by volume, and more preferably less than 10% by volume, based on the total amount of the raw material gas or the synthetic gas.

(Ethanol conversion process)
Syngas is converted to ethanol in the ethanol conversion step. In the ethanol conversion step, the synthetic gas may be converted to ethanol by either a gas-utilizing microorganism or a metal catalyst as described above, but it is preferably converted by a gas-utilizing microorganism. When converting to ethanol using a gas-utilizing microorganism, a synthetic gas is supplied to a microbial fermenter, and the synthetic gas is microbially fermented in the microbial fermenter to produce ethanol. The microbial fermentation tank is preferably a continuous fermentation apparatus.

Generally, any shape of the microbial fermenter can be used, and examples thereof include a stirring type, an airlift type, a bubble tower type, a loop type, an open bond type, and a photobio type. In the present invention, the microbial fermenter is used. However, a known loop reactor having a main tank portion and a reflux portion can be preferably used.
As the synthetic gas to be supplied to the microbial fermenter, the synthetic gas obtained through the above-mentioned synthetic gas purification step may be used as it is as the synthetic gas, or another predetermined gas may be added and then supplied. As another predetermined gas, for example, at least one selected from the group consisting of sulfur compounds such as sulfur dioxide, phosphorus compounds, and nitrogen compounds can be mentioned.

The synthetic gas and the microbial culture solution may be continuously supplied to the microbial fermenter, but it is not necessary to supply the synthetic gas and the microbial culture solution at the same time, and the microbial fermenter to which the microbial culture solution has been supplied in advance is used. Syngas may be supplied. It is known that certain anaerobic microorganisms produce ethanol and the like from substrate gases such as syngas by fermentation, and these gas-utilizing microorganisms are cultivated in a liquid medium. For example, a liquid medium and gas-utilizing bacteria may be supplied and contained, and the synthetic gas may be supplied into the microbial fermentation tank while stirring the liquid medium in this state. As a result, gas-utilizing bacteria can be cultivated in a liquid medium, and ethanol can be produced from the synthetic gas by the fermentation action thereof.

In the microbial fermentation tank, the temperature of the medium (culture temperature) may be any temperature, but is preferably about 30 to 45 ° C, more preferably about 33 to 42 ° C, and even more preferably 36.5 to 37. The temperature can be about 5 ° C. The culturing time is preferably 1 hour or longer in continuous culturing, more preferably 7 days or longer, particularly preferably 30 days or longer, most preferably 60 days or longer, and although the upper limit is not particularly set, equipment maintenance, etc. From the viewpoint, it is preferably 720 days or less, more preferably 365 days or less. In addition, the culture time means the time from the addition of the inoculum to the culture tank until the total amount of the culture solution in the culture tank is discharged.

The microorganisms (species) contained in the microbial culture solution are not particularly limited as long as ethanol can be produced by microbial fermentation of synthetic gas using carbon monoxide as a main raw material. For example, the microorganism (species) is preferably one that produces ethanol from syngas by the fermentation action of gas-utilizing bacteria, and particularly preferably a microorganism having a metabolic pathway of acetyl-COA. Among the gas-utilizing bacteria, the genus Clostridium is more preferable, and Clostridium autoethanogenum, Clostridium ljungdahlii, Clostridium aceticum, and Clostridium carboxydilance. Clostridium carboxidivorans), Moorella thermoacetica, Acetobacterium woodii and the like. Of these, Clostridium autoethanogenum is particularly preferred.

The medium used for culturing the above-mentioned microorganisms (species) is not particularly limited as long as it has an appropriate composition according to the bacteria, but is not particularly limited, but is the main component water and nutrients dissolved or dispersed in the water (for example, vitamins, etc.). It is a liquid containing (phosphoric acid, etc.). The composition of such a medium is prepared so that gas-utilizing bacteria can grow well. For example, when the genus Clostridium is used as a microorganism, "0907" to "00099" of US Patent Application Publication No. 2017/260552 can be referred to.

By microbial fermentation, a culture solution containing ethanol (ethanol-containing culture solution) is obtained. The ethanol-containing culture is then subjected to a separation step.
In the separation step, for example, the ethanol-containing culture solution is heated to 23 to 500 ° C. under the condition of 0.01 to 1000 kPa (absolute pressure) to obtain a liquid or solid component containing microorganisms and a gas component containing ethanol. It is good to separate. By carrying out such a separation step, in the distillation operation at the time of separation and purification of ethanol, which will be described later, foaming does not occur in the distillation apparatus, so that the distillation operation can be continuously performed. In addition, ethanol can be efficiently separated and purified at the time of separation and purification described later.

In the above separation step, from the viewpoint of efficiently separating a liquid or solid component containing microorganisms, their carcasses, proteins derived from microorganisms, etc., and a gas component containing ethanol, it is more preferable under the condition of 10 to 200 kPa. Of the ethanol-containing culture solution under conditions of 50 to 150 kPa, more preferably under normal pressure, preferably at a temperature of 50 to 200 ° C, more preferably at a temperature of 80 ° C to 180 ° C, still more preferably at a temperature of 100 to 150 ° C. Perform heating.
The ethanol-containing gas component obtained in the above separation step may be liquefied by condensation to obtain an ethanol-containing liquid. The apparatus used in the liquefaction step is not particularly limited, but it is preferable to use a heat exchanger, particularly a condenser (condenser). Examples of the condenser include a water-cooled type, an air-cooled type, an evaporation type, and the like, and the water-cooled type is preferable among them. The condenser may have one stage or a plurality of stages.

Further, in the separation step, instead of separating the liquid or solid component containing microorganisms and the gas component containing ethanol as described above, the solid component containing microorganisms and the liquid component containing ethanol (ethanol-containing liquid) are separated. Separation may be performed by a solid-liquid separation device such as a solid-liquid separation filter device.

After the separation step, a pre-purification step of further purifying the ethanol-containing liquid may be performed. The pre-stage purification step means a purification step performed before the first purification step described later. Further, when the ethanol-containing liquid obtained by the microbial fermentation has already been removed of components such as microorganisms, the pre-purification step may be performed without going through the above-mentioned separation step.
The first-stage purification step is a step of separating the ethanol-containing liquid into a distillate having a high ethanol concentration and a canned liquid having a low ethanol concentration. The equipment used in the purification process is, for example, a distillation apparatus, a treatment apparatus containing a permeation vaporization membrane, a treatment apparatus containing a zeolite membrane, a treatment apparatus for removing a low boiling point substance having a boiling point lower than that of ethanol, and a high boiling point substance having a boiling point higher than that of ethanol. Examples thereof include a processing device for removing the boiling point, a processing device containing an ion exchange membrane, and the like. These devices may be used alone or in combination of two or more. As a unit operation, a distillation apparatus or membrane separation can be preferably used, and a distillation apparatus is more preferable. Further, as the membrane separation, a zeolite membrane can be preferably used.

When using a distillation device, perform heat distillation. In heat distillation, desired ethanol can be obtained as a distillate with high purity. The temperature in the distillation apparatus during the distillation of ethanol is not particularly limited, but is preferably 110 ° C. or lower, and more preferably about 70 to 105 ° C. By setting the temperature in the distillation apparatus to the above range, separation of ethanol and other components, that is, distillation of ethanol can be performed more reliably.

In heat distillation, an ethanol-containing liquid is introduced into a distillation apparatus equipped with a heater using steam at 100 ° C. or higher, the temperature at the bottom of the distillation column is raised to 90 ° C. or higher within 30 minutes, and then the ethanol is described above. It is advisable to introduce the containing liquid from the central part of the distillation column. Further, in the heating distillation using a distillation apparatus, it is preferable to carry out the distillation step within ± 15 ° C. in the temperature difference between the bottom portion, the middle portion of the column and the top portion of the column. When the temperature difference is within ± 15 ° C., it becomes easy to obtain high-purity ethanol. The distillation temperature difference is preferably ± 13 ° C, more preferably ± 11 ° C. With these distillation temperature differences, separation from other components, that is, purification by distillation of ethanol can be performed more reliably.

The pressure in the distillation apparatus at the time of distillation of ethanol may be normal pressure, but is preferably less than atmospheric pressure, more preferably about 60 to 95 kPa (absolute pressure). By setting the pressure in the distillation apparatus within the above range, the separation efficiency of ethanol can be improved, and thus the yield of ethanol can be improved.

Ethanol obtained through the first-stage purification step is used as a raw material for obtaining an ethylene-containing product in the ethylene production step described later. "Ethanol" used as a raw material in the present invention does not mean pure ethanol as a compound (chemical formula: ethanol represented by CH ₃ CH ₂ OH), but is a composition containing impurities, and is "raw material ethanol". Also called. Impurities are contained in the raw material ethanol produced through each of the above steps, and most of them are waste-derived compounds.

Further, the raw material ethanol may be produced from synthetic gas using a metal catalyst as described above. Examples of the metal catalyst include a hydroactive metal or an aggregate of a hydroactive metal and a coactive metal. The active metal hydride may be any metal conventionally known as a metal capable of synthesizing ethanol from a mixed gas. For example, alkali metals such as lithium and sodium, manganese, renium and the like are included in Group 7 of the periodic table. Examples thereof include elements belonging to Group 8 of the periodic table such as ruthenium, elements belonging to Group 9 of the periodic table such as cobalt and rhodium, and elements belonging to Group 10 of the periodic table such as nickel and palladium.
One of these hydrogenated active metals may be used alone, or two or more thereof may be used in combination. As the hydrogenated active metal, rhodium or ruthenium, such as a combination of rhodium, manganese and lithium, a combination of ruthenium, renium and sodium, is used because the CO conversion rate is further improved and the selectivity of ethanol is improved. A combination of an alkali metal and another hydrogenated active metal is preferable.

Examples of the coactive metal include titanium, magnesium, vanadium and the like. Since the coactive metal is supported in addition to the hydrogenated active metal, the CO conversion rate and the ethanol selectivity can be further increased.
As the metal catalyst, a rhodium-based catalyst is preferable. As the rhodium-based catalyst, a metal catalyst other than the rhodium-based catalyst may be used in combination. Examples of other metal catalysts include copper alone or a catalyst in which copper and a transition metal other than copper are supported on a carrier.
When a metal catalyst is used, a product containing acetaldehyde or acetic acid in addition to ethanol is usually obtained. Therefore, the product may be used as a raw material ethanol through a pre-purification step such as distillation.

The pre-stage purification step may be omitted. That is, after ethanol production, both the pre-stage purification step and the first purification step described later may not be performed as the purification step, or only the first purification step may be performed. In this case, the above-mentioned ethanol-containing liquid becomes the raw material ethanol, and it is preferable that the first purification step is carried out by a distillation apparatus or membrane separation, and heat distillation using a distillation apparatus is particularly preferable. As mentioned above. Of course, when the second purification step is performed, both the pre-stage purification step and the first purification step may be omitted. However, it is preferable to carry out the first-stage purification step, and it is more preferable to carry out the first purification step in combination.

The raw material ethanol has an ethanol purity (that is, ethanol content) of, for example, 85% by volume or more. When the ethanol purity is equal to or higher than the above lower limit value, the polymerization reaction using ethylene as a raw material proceeds suitably by going through at least one of the first and second purification steps, and the polymer obtained from ethylene The quality is good. The ethanol purity of the raw material ethanol is preferably 90% by volume or more, more preferably 95% by volume or more, still more preferably 99.5% by volume or more. Further, the raw material ethanol may have an ethanol purity of less than 100% by volume.
Further, as the raw material ethanol, a commercially available product may be used as long as it contains ethanol derived from waste.

[Ethylene production process]
The raw material ethanol is converted from ethanol to ethylene by an ethylene production step, whereby an ethylene-containing product is obtained. Specifically, the raw material ethanol may be brought into contact with the catalyst to be converted into ethylene. The raw material ethanol is converted to ethylene by a dehydration reaction.

The catalyst used is not limited as long as it can convert ethanol to ethylene, but is limited to zeolite, modified zeolite such as P-modified zeolite, silica-alumina, alumina, silicate-ized, titanized, zirconated or fluorinated. Examples thereof include acid catalysts such as alumina and silicoaluminophosphate (hereinafter, these may be collectively referred to as "zeolite or alumina-based catalysts"). In addition, a heteropolyacid-supported catalyst and the like can also be mentioned.

As the zeolite, those containing at least one kind of 10-membered ring in the structure are advantageous, and have a microporous material composed of silicon, aluminum, oxygen and boron as an optional component, and specifically, MFI (ZSM-). 5, Silicalite-1, Boronite C, TS-1), MEL (ZSM-11, Silicalite-2, Boralite D, TS-2, SSZ-46), FER (Ferrier Zeolite, FU-9, ZSM-35) ), MTT (ZSM-23), MWW (MCM-22, PSH-3, ITQ-1, MCM-49), TON (ZSM-22, Theta-1, NU-10), EUO (ZSM-50, EU) -1), MFS (ZSM-57), ZSM-48 and the like.

As the zeolite, a zeolite having a Si / Al ratio of 10 or more is preferable. Zeolites having a Si / Al ratio of 10 or more preferably have a Si / Al ratio of 100 or more, and preferably contain at least one selected from MFI and MEL.

The zeolite is also preferably a dealuminated zeolite. For dealuminated zeolites, it is advantageous to remove about 10% by weight of aluminum. It is advantageous to perform this dealumination by steaming and then leaching as needed.
It is advantageous that the zeolite and the dealuminated zeolite are basically H-type. Further, as a sub-component (component of about 50% or less), at least one selected from metal compensating ions such as Na, Mg, Ca, La, Ni, Ce, Zn and Co can be contained.

The zeolite is mixed with a binder, preferably an inorganic binder, and formed into a desired shape such as pellets. The binder is selected to be durable to the temperature and other conditions used in the dehydration process of the present invention. Binders are at least one inorganic material selected from gels containing clay, silica, metal silicates, metal oxides (eg ZrO ₂ ) or mixtures of silica and metal oxides.

The P-modified zeolite is a phosphorus-modified zeolite. In the ethylene production step, it is also preferable to use P-modified zeolite. The phosphorus-modified zeolite is, for example, a zeolite having a microporous initial atomic ratio Si / Al ratio of 4 to 500, specifically, MFI, MOR, MEL, clinoptilolite, FER, MWW, TON, EUO. , MFS, ZSM-48 and the like. The initial atomic ratio Si / Al ratio is preferably 100 or less, and more preferably 4 to 30. The P-modified zeolite of this production method can also be obtained based on an inexpensive zeolite having a low Si / Al ratio (30 or less).

Further, the P-modified zeolite can also be further modified with at least one metal selected from Mg, Ca, La, Ni, Ce, Zn, Co, Ag, Fe, and Cu.
The phosphorus atom content in the P-modified zeolite is at least 0.05% by mass, preferably 0.3 to 7% by mass, which is advantageous.
Further, it is advantageous that at least 10% by mass of aluminum is extracted and removed from the zeolite by leaching with respect to the zeolite as a raw material.

The catalyst using the P-modified zeolite may be the P-modified zeolite itself as a catalyst, or a compounded P-modified zeolite in which the P-modified zeolite and other materials are combined. The compounding type can improve the hardness or catalytic activity of the catalyst.
Examples of the material that can be mixed with the P-modified zeolite include various inert or catalytically active materials, and various binder materials. Specific examples include kaolin, other clay-like compositions, various forms of rare earth metals, phosphates, alumina or alumina sol, titania, zirconia, quartz, silica or silica sol and mixtures thereof. These components are effective in increasing the compressive strength of the catalyst and compounding catalyst. The catalyst can be molded into pellets, spheres, extruded into other shapes, or spray dried particles. The amount of P-modified zeolite contained in the final catalyst product is 10 to 90% by mass, preferably 20 to 70% by mass of the total catalyst.
A preferred example of the P-modified zeolite is silicoaluminophosphate, more preferably silicoaluminophosphate of the AEL group, and a typical example thereof is SAPO-11. SAPO-11 is based on ALPO-11 and has an Al / P ratio of basically 1 atom / atom. By adding a silicon precursor during synthesis and inserting silicon into the ALPO skeleton, acid sites are formed on the surface of the micropores of the 10-membered zeolite. The silicon content is 0.1 to 10 atomic% (Al + P + Si is 100).

It is also preferable to use alumina (particularly γ-alumina) as a catalyst in the ethylene production step. It is also preferred to use silicate, zirconeated, titanated or fluorinated alumina. Alumina is generally characterized by having a wide range of acid intensity distributions and Lewis-type and Bronsted-type acid sites. As the alumina, activated alumina may be used.

Alumina also preferably improves the selectivity of the catalyst by precipitating silicon, zirconium, titanium, fluorite, etc. on the surface. That is, the selectivity of the catalyst may be improved by silicate-forming, zirconating, or titanating. Suitable commercially available alumina, preferably eta or gamma alumina, having a surface area of 10 to 500 m ² / g and an alkali content of 0.5% or less may be used for producing such a catalyst. Further, it is preferable to add silicon, zirconium, titanium and the like in a total amount of 0.05 to 10% by mass. Addition of these metals may be carried out at the time of producing alumina, may be carried out in addition to alumina after production, and these metals may be added in the form of precursors. Further, the fluorinated alumina itself is known and can be produced according to the prior art.

In the ethylene production step, it is also preferable to use a heteropolyacid-supported catalyst as a catalyst. The heteropolyacid-supported catalyst comprises a heteropolyacid supported on a suitable catalyst carrier. The term "heteropoly acid" is in the form of a free acid or alkali metal salt, alkaline earth metal salt, ammonium salt, bulky cation salt, and / or metal salt (in these cases, the salt is a complete or partial salt). Refers to a heteropolyacid compound in the form of a heteropolyate such as (which may be any salt).
Heteropolyacid anions typically contain 12-18 oxygen-bonded polyvalent metal atoms known as peripheral atoms that surround one or more central atoms in a symmetrical manner. Peripheral atoms are appropriately selected from molybdenum, tungsten, vanadium, niobium, tantalum, and combinations thereof. The central atom is preferably silicon or phosphorus. Further, the central atom is any one selected from the atoms of groups I to VIII in the periodic table of the element, for example, copper, beryllium, zinc, cobalt, nickel, boron, aluminum, gallium, iron, cerium and arsenic. , Antimony, bismuth, chromium, rhodium, silicon, germanium, tin, titanium, zirconium, vanadium, sulfur, tellurium, manganese nickel, platinum, thorium, hafnium, tellurium, iodine and the like. Suitable heteropolyacids include Keggin, Wells-Dawson and Anderson-Evans-Perlov heteropolyacids.

The heteropolyacid component of the heteropolyacid-supported catalyst is preferably heteropolytungstic acid, which is a heteropolyacid whose peripheral atom is a tungsten atom. Preferred heteropolytungstic acid is any one whose main component is a Keggin or Wells-Dawson structure.
Examples of suitable heteropolytungstic acids are 18-phosphotungstic acid (H ₆ [P ₂ W ₁₈ O ₆₂ ] · xH ₂ O), 12-phosphotungstic acid (H ₃ [PW ₁₂ O ₄₀ ] · xH ₂ O). , 12-Tungstic acid (H ₄ [SiW ₁₂ O ₄₀ ] · xH ₂ O), cesium hydrogen silicate (Cs ₃ H [SiW ₁₂ O ₄₀ ] · xH ₂ O), monopotassium phosphotungstic acid (KH ₅₎ [P ₂ W ₁₈ O ₆₂ ] · xH ₂ O), monosodium _12- caity tungstic acid (NaK ₃ [SiW ₁₂ O ₄₀ ] · xH ₂ O), and potassium phosphotungstic acid (K ₆ [P ₂ W ₁₈ O) ₆₂ ] ・ xH ₂ O) can be mentioned. Mixtures of two or more different heteropolytungstic acids and salts can also be used.

More preferably, the heteropolyacid component of the heteropolyacid-bearing catalyst is silicate-tungstic acid, phosphotungstic acid, and mixtures thereof, such as 12-ca-tungstic acid (H ₄ [SiW ₁₂ O ₄₀ ] · xH ₂ O), 12 -Selected from phosphotungstic acid (H ₃ [PW ₁₂ O ₄₀ ] · xH ₂ O) and mixtures thereof. More preferably, the heteropolyacid is silicate tungstic acid, and most preferably the heteropolyacid is 12-cay tungstic acid.

The molecular weight of the heteropolyacid is preferably more than 700 and less than 8500, more preferably more than 2800 and less than 6000. Such heteropolyacids also include these dimerization complexes.

The catalyst carrier used in the heteropolyacid-supported catalyst may be any suitable catalyst carrier known in the art. Suitable raw materials for catalyst carriers include mordenite (eg montmorillonite), clay, bentonite, diatomaceous soil, titania, activated carbon, alumina, silica, silica-alumina, silica-titania cogel, silica-zirconia cogel, carbon coated alumina, zeolite, zinc oxide. , And flame thermal decomposition oxides are included. A silica-based catalyst carrier such as a silica gel carrier and a carrier produced by flame hydrolysis of SiCl4 is preferable.
The shape of the catalyst carrier is not particularly limited, and may be, for example, a powder form, a granular form, a pelletized form, a spherical form, or an extruded form.

The raw material ethanol is not particularly limited, but is preferably converted into ethylene by contacting the catalyst in the gas phase. Further, the raw material ethanol may be further mixed with water, and an optional component may be appropriately mixed in addition to the raw material ethanol and water, and one or both of water and the optional component is a gas together with the raw material ethanol. It is good to bring it into contact with the catalyst.
For example, a reaction vessel is filled with a catalyst, and the reaction vessel filled with the catalyst is supplied with raw material ethanol or raw material ethanol and at least one selected from water and other optional components as a gas, and a gas phase is supplied. It is advisable to discharge the ethylene-containing product from the reaction vessel in the gas phase by performing a dehydration reaction. If ethanol remains in the gas discharged from the reaction vessel, the ethanol-containing component may be separated from the ethylene-containing product and the ethanol-containing component may be supplied to the reaction vessel again.

In the case of a zeolite or alumina-based catalyst, the temperature of the reaction vessel is, for example, 280 to 600 ° C, preferably 300 to 550 ° C, and more preferably 330 to 530 ° C. The pressure (absolute pressure) of the reaction vessel is, for example, 50 kPa to 3 MPa, preferably 50 kPa to 1 MPa, and more preferably 0.12 MPa to 0.65 MPa.

In the case of a heteropolyacid-supported catalyst, the temperature of the reaction vessel is, for example, 170 ° C. or higher, preferably 180 to 270 ° C., more preferably 190 to 260 ° C., and further preferably 200 to 250 ° C. Is. The pressure is preferably in the range of 0.1 to 4.5 MPa, more preferably 1.0 to 3.5 MPa, and even more preferably 1.0 to 2.8 MPa.
In the case of a heteropolyacid-supported catalyst, the heteropolyacid-supported catalyst is heated to a temperature of 220 ° C. or higher and kept at that temperature for a sufficient period of time before coming into contact with the raw material ethanol. The bound water may be removed from.

[First and second purification steps]
In the method for producing ethylene of the present invention, as described above, a first purification step of purifying the raw material ethanol before the ethylene production step, or a second purification step of purifying the ethylene-containing product after the ethylene production step. Do at least one of the above. Also, preferably, both the first and second purification steps are performed.
In the present specification, when the second purification step is performed, the ethylene-containing product purified by the second purification step is referred to as "ethylene" produced by the production method of the present invention, and the second purification step is performed. When the purification step of is omitted, the ethylene-containing product obtained in the ethylene production step is referred to as "ethylene" produced by the production method of the present invention. The "ethylene" produced by the production method of the present invention may be composed of ethylene alone, or may be a composition containing impurities that are inevitably mixed even after being synthesized or purified.

In the first purification step, the raw material ethanol is composed of an aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms, an aliphatic saturated hydrocarbon having 3 to 14 carbon atoms, an alcohol having 3 to 10 carbon atoms, and 3 to 10 carbon atoms. It is preferable to remove at least one organic compound selected from the ether.
The waste contains various components, and therefore, the raw material ethanol produced from the waste contains various organic compounds. Further, among the organic compounds, the organic compound having the above carbon number often remains in the raw material ethanol obtained through various steps. If such an organic compound remains in the raw material ethanol, it inhibits the dehydration reaction in the ethylene production step and the polymerization reaction using ethylene in the subsequent stage, and deteriorates the quality of the polymer obtained from ethylene. Sometimes. Therefore, by removing hydrocarbons, alcohols, and ethers having a specific carbon number in the first purification step, the polymerization reaction of ethylene can be suitably promoted, and the quality of the obtained polymer can be easily improved.

On the other hand, in the second purification step, the produced ethylene-containing product has an aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms, an aliphatic saturated hydrocarbon having 3 to 14 carbon atoms, and an aliphatic saturated hydrocarbon having 3 to 10 carbon atoms. It is preferable to remove at least one selected from alcohol, a specific organic compound consisting of an ether having 3 to 10 carbon atoms, carbon monoxide, and oxygen.
The “removal” referred to in the first and second purification steps includes not only a mode in which the target substance is completely removed from the raw material ethanol or ethylene-containing product, but also a mode in which the content of the target substance is reduced.

Also in the second purification step, as described in the description of the first purification step, the ethylene polymerization reaction can be suitably promoted by removing hydrocarbons, alcohols and ethers having a specific carbon number, and also. The quality of the obtained polymer is also easily improved.
Carbon monoxide and oxygen have high electronegativity and may inhibit the polymerization reaction in the polymerization reaction of ethylene. For example, when a specific catalyst such as a Ziegler-Natta catalyst is used, the polymerization reaction may be inhibited. Further, since oxygen can be a polymerization initiator in radical polymerization such as high-pressure polymerization, the polymerization may run out of control due to a large amount of oxygen. Therefore, by removing carbon monoxide and oxygen from the ethylene-containing composition in the second purification step, it is possible to prevent the ethylene polymerization reaction from being inhibited by these.

The ethylene produced in the present invention preferably has a carbon monoxide content of 1% by volume or less by removing carbon monoxide. By setting the content to 1% by volume or less, it is possible to prevent the polymerization reaction from being inhibited by carbon monoxide in the polymerization reaction using ethylene. From such a viewpoint, the content of carbon monoxide is more preferably 0.5% by volume or less, and further preferably 0.1% by volume or less. Further, the ethylene produced in the present invention does not have to contain carbon monoxide at all, and therefore, the lower limit of the content of carbon monoxide is 0% by volume.

The ethylene produced in the present invention preferably has an oxygen content of 1% by volume or less due to the removal of oxygen. By setting the content to 1% by volume or less, it is possible to prevent the polymerization reaction from being inhibited by oxygen in the polymerization reaction using ethylene. From such a viewpoint, the oxygen content is more preferably 0.5% by volume or less, and further preferably 0.1% by volume or less. Further, the ethylene produced in the present invention does not have to contain oxygen at all, and therefore, the lower limit of the oxygen content is 0% by volume.

Aliphatic unsaturated hydrocarbons having 3 to 14 carbon atoms may be removed in the first purification step, the second purification step, or both, but the carbon number 3 to 14 carbon atoms removed in any of the steps. The aliphatic unsaturated hydrocarbon preferably contains propylene. When propylene is contained in ethylene, when the polymerization reaction is carried out using the ethylene, propylene becomes a branched chain of the polymer, so that the branched chain can be reduced by removing the propylene. Therefore, as will be described later, it is particularly preferable to remove it when it is desired to reduce the branched chains of the polymer, such as when producing high-density polyethylene (HDPE) from ethylene.

The ethylene produced in the present invention preferably has a propylene content of 1% by volume or less by removing propylene. By setting the volume to 1% by volume or less, the effect of reducing the number of branched chains can be exhibited. From such a viewpoint, the content of propylene is more preferably 0.5% by volume or less, and further preferably 0.1% by volume or less. Further, the ethylene produced in the present invention does not have to contain propylene at all, and therefore, the lower limit of the content of propylene is 0% by volume.

Further, the aliphatic saturated hydrocarbon having 3 to 14 carbon atoms may be removed in the first purification step, the second purification step, or both, but the carbon number 3 to 14 is removed in any of the steps. It is preferable that the aliphatic saturated hydrocarbon of the above contains an aliphatic saturated hydrocarbon having 6 to 14 carbon atoms. The aliphatic saturated hydrocarbon having 6 to 14 carbon atoms may be linear or may have at least one of a branched structure and a cyclic structure, but is preferably linear. Specific examples of aliphatic saturated hydrocarbons having 6 to 14 carbon atoms are at least one selected from n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and n-tetradecane. Is preferable.
These aliphatic saturated hydrocarbons having a relatively large number of carbon atoms (6 to 14 carbon atoms) are contained in a relatively large amount in the raw material ethanol derived from waste. On the other hand, these aliphatic saturated hydrocarbons are highly compatible with fats and oils contained in foods, and when the polymer produced from ethylene produced in the present invention is used as a packaging material for foods, it becomes a food. There is concern about the outflow of Therefore, it is preferable in terms of food safety to remove aliphatic saturated hydrocarbons having a relatively large number of carbon atoms.
Further, the aliphatic saturated hydrocarbon having 3 to 14 carbon atoms removed in any of the above steps is an aliphatic saturated hydrocarbon having 10 to 14 carbon atoms from the viewpoint of being contained in a large amount in the raw material ethanol derived from waste. It is preferable to include it.

The ethylene produced in the present invention has an aliphatic saturated hydrocarbon content of 6 to 14 carbon atoms of 0.3% by volume or less by removing the aliphatic saturated hydrocarbon having 6 to 14 carbon atoms. It is preferably 0.2% by volume or less, and more preferably 0.1% by volume or less. Further, the ethylene produced in the present invention may not contain any aliphatic saturated hydrocarbon having 6 to 14 carbon atoms, and therefore, the lower limit of the content of the aliphatic saturated hydrocarbon having 6 to 14 carbon atoms. Is 0% by volume.

Further, the alcohol having 3 to 10 carbon atoms may be removed in the first purification step, the second purification step, or both of them, but the alcohol having 3 to 10 carbon atoms removed in any of the steps may be used. For example, at least one selected from 1-propanol, 2-propanol, 1-butanol, 2-butanol, and tert-butanol is included. These alcohols are contained in a relatively large amount in the raw material ethanol derived from waste, and by removing these alcohols in the first purification step, the second purification step, or both of them, polymerization using ethylene, which will be described later, is carried out. The reaction can proceed favorably, and the quality of the obtained polymer can be easily improved.

Further, it is preferable that the alcohol having 3 to 10 carbon atoms removed in any of the above steps contains 2-propanol. When 2-propanol is contained in ethylene, when the polymerization reaction is carried out using that ethylene, 2-propanol becomes a branched chain of the polymer. Therefore, removing 2-propanol reduces the branched chain in the polymer. be able to. Therefore, it is particularly preferable to remove 2-propanol when it is desired to reduce the branched chains of the polymer, such as when producing high-density polyethylene (HDPE) from ethylene, as will be described later.

The ethylene produced in the present invention preferably has a 2-propanol content of 0.3% by volume or less by removing 2-propanol. By setting the volume to 0.3% by volume or less, the effect of reducing the number of branched chains can be easily exerted. From such a viewpoint, the content of 2-propanol is more preferably 0.1% by volume or less, still more preferably 0.05% by volume or less. Further, the ethylene produced in the present invention does not have to contain 2-propanol at all, and therefore, the lower limit of the content of 2-propanol is 0% by volume.

Ethers having 3 to 10 carbon atoms may be removed in the first purification step, the second purification step, or both, but ethers having 3 to 10 carbon atoms removed in any of the steps may include, for example, ethers having 3 to 10 carbon atoms. , Diethyl ether, at least one selected from dibutyl ether. These ethers are contained in a relatively large amount as compared with the raw material ethanol derived from waste, and by removing these ethers in the first purification step, the second purification step, or both of them, a polymerization reaction using ethylene, which will be described later, is carried out. Is preferably carried out, and the quality of the obtained polymer is also easily improved.

The ether having 3 to 10 carbon atoms removed in any of the above steps preferably contains dibutyl ether. Since dibutyl ether is a volatile organic compound (VOC), it is advantageous in that removing dibutyl ether can reduce the risk of adverse effects such as health risks caused by VOC.

The ethylene produced in the present invention preferably has a dibutyl ether content of 0.3% by volume or less due to the removal of dibutyl ether. By setting the volume to 0.3% by volume or less, the effect of reducing the risk of adverse effects such as health risks can be easily exerted. From such a viewpoint, the content of dibutyl ether is more preferably 0.1% by volume or less, and further preferably 0.05% by volume or less. Further, the ethylene produced in the present invention does not have to contain dibutyl ether at all, and therefore, the lower limit of the content of dibutyl ether is 0% by volume.

Further, since water is produced by the dehydration reaction in the ethylene production step, it is preferable that at least water is removed in the second purification step. Further, since unreacted ethanol generally remains in the ethylene-containing product produced in the ethylene production step, it is preferable to remove the unreacted ethanol as well. By removing water and ethanol, the polymerization reaction using ethylene, which will be described later, can be suitably carried out, and the quality of the obtained polymer can be easily improved.

The ethylene produced in the present invention preferably has a water content of 0.3% by volume or less because water is removed in the second purification step. When the content is 0.3% by volume or less, the polymerization reaction using ethylene can be easily carried out, and the quality of the obtained polymer can be easily improved. From such a viewpoint, the water content is more preferably 0.1% by volume or less, and further preferably 0.05% by volume or less. Further, the ethylene produced in the present invention does not have to contain water at all, and therefore, the lower limit of the water content is 0% by volume.

The ethylene produced in the present invention preferably has an ethanol content of 0.3% by volume or less by removing ethanol in the second purification step. When the content is 0.3% by volume or less, the polymerization reaction using ethylene can be easily carried out, and the quality of the obtained polymer can be easily improved. From such a viewpoint, the content of ethanol is more preferably 0.1% by volume or less, further preferably 0.05% by volume or less. Further, the ethylene produced in the present invention does not have to contain ethanol at all, and therefore, the lower limit of the ethanol content is 0% by volume.

The ethylene produced in the present invention is generally a gas, and ethylene, which is the gas, is used as an inorganic gas (oxygen, carbon monoxide, etc.) and an organic gas using GC-TCD and GC-FID. By analyzing and, the volume% of each of the above components can be measured.

The purification methods in each of the first and second purification steps include a water separator consisting of a gas chiller, a separator using an adsorbent such as activated carbon, a pressure swing adsorption type separator (PSA), and a temperature swing adsorption type. Separator (TSA), pressure-temperature swing adsorption type separator (PTSA), low temperature separation method (deep cooling method) separation device, water-soluble impurity separator such as scrubber, desulfurization device (sulfide separation device), membrane separation Examples thereof include a type separation device, a distillation device, a separation device having chromatography, and a solution absorption device.

As the low temperature separation method, various forms can be used, and for example, a condenser is used. The solution absorption device is a device including an absorption solution that selectively absorbs a predetermined gas component by contacting the gas, and an alkaline solution such as an amine solution may be used as the absorption solution. For example, when an alkaline solution is used in the first purification step, carbon dioxide and the like in the gasified raw material ethanol can be absorbed.

In the first purification step, as described above, an aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms, an aliphatic saturated hydrocarbon having 3 to 14 carbon atoms, an alcohol having 3 to 10 carbon atoms, and 3 to 10 carbon atoms It is preferable that one of the ethers of the above is removed, but it is more preferable that one having a relatively large number of carbon atoms is removed, and in particular, an aliphatic unsaturated hydrocarbon having 6 to 14 carbon atoms is removed. Is preferable. The organic compound having a large number of carbon atoms can be easily removed in the first purification step due to the difference in molecular weight from ethanol, and by removing the organic compound, the reaction in the ethylene production step can be more appropriately proceeded.
In the first purification step, the method for removing the aliphatic unsaturated hydrocarbon having 6 to 14 carbon atoms is not particularly limited, but it is preferable to remove the aliphatic unsaturated hydrocarbon by a separator having chromatography. As the chromatography, reverse phase chromatography or the like may be used. Further, it may be removed by a distillation apparatus, adsorption of activated carbon or the like.

In the second purification step, it is preferable that either the water produced in the ethylene production step or the unreacted ethanol is removed, and it is preferable that both of them are removed. Further, in the second purification step, as described above, it is preferable to remove at least one selected from the specific organic compound, carbon monoxide, and oxygen, and the specific organic compound has a relatively low molecular weight and is low. It is more preferable that the molecular weight organic compound (for example, having 3 to 5 carbon atoms) is removed. That is, in the first purification step, aliphatic saturated hydrocarbons having 6 to 14 carbon atoms are removed, and in the second purification step, in addition to water and unreacted ethanol, a specific low molecular weight having a relatively low molecular weight is specified. It is more preferable that at least the molecular weight organic compound is removed, and it is also preferable that carbon monoxide and oxygen are further removed in addition to these in the second purification step.
It is more preferred that the particular organic compound removed in the second purification step specifically comprises at least one selected from low molecular weight alcohols such as 2-propanol and low molecular weight ethers such as diethyl ether. .. Further, it is more preferable that the specific organic compound removed in the second purification step further contains, in addition to these, a low molecular weight aliphatic unsaturated hydrocarbon such as propylene. That is, in the second purification step, it is more preferable that propanol and diethyl ether are removed as the low molecular weight organic compound, and it is particularly preferable that propylene is further removed in addition to these.
Low molecular weight organic compounds can be efficiently removed from ethylene together with unreacted ethanol, carbon monoxide, oxygen and the like by using a specific separation device.
Further, diethyl ether can be a raw material for producing ethylene together with ethanol in the ethylene production step. Therefore, it is preferable to remove diethyl ether in a larger proportion in the second purification step than in the first purification step. The ratio is a ratio to the raw material ethanol in the first purification step and to the ethylene-containing product in the second purification step.

The second purification step is not particularly limited, but it is preferable to perform purification by a separation device of a low temperature separation method. Specifically, a method of solidifying ethylene to separate it by a condenser using a refrigerant (chiller) cooled to a temperature below the melting point of ethylene (-170 ° C. or lower at normal pressure) can be mentioned.
In this case, substances such as water, carbon dioxide, ethanol and other organic compounds having a melting point higher than that of ethylene are removed by using a condenser in the previous stage having a refrigerant temperature higher than that of the above condenser. It is good. The condensers in the first stage include, for example, a first condenser in which the temperature of the refrigerant is relatively high (for example, 0 to 25 ° C. at normal pressure) and a second condenser in which the temperature of the refrigerant is lower than that of the first condenser. It may be used in combination with a vessel (for example, −50 to −90 ° C. at normal pressure).
Further, the condenser may be of any form, and the ethylene-containing product of the gas phase may be brought into contact with a metal tube or the like through which the refrigerant is passed, or the refrigerant and the ethylene-containing product may be brought into direct contact with each other. ..

[Method for producing polymer]
The ethylene produced in the present invention can be used for various purposes, but is preferably used in a polymerization step for producing a polymer containing a structural unit derived from ethylene. In the polymerization step, a monomer containing ethylene is polymerized to obtain a polymer. The polymer may be homopolyethylene obtained by polymerizing ethylene alone, or may be a copolymer obtained by polymerizing ethylene and a monomer component other than ethylene.

The polymer is preferably a polyethylene resin such as low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and ultrahigh molecular weight polyethylene (UHMWPE).
Further, any polymer containing a structural unit derived from ethylene may be used, and for example, it may be a copolymer with a monomer other than ethylene. The monomer other than ethylene is not particularly limited, but propylene, 1-butene, 2-butene, isobutene, 1-pentene, 1-hexene, 1-heptene, 1-octene, vinyl acetate, methyl acrylate, Ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, acrylic nitrile, vinyl fluoride, vinyl chloride, vinyl bromide, tetrafluoroethylene, diethyl maleate, Examples thereof include diethyl fumarate and carbon monoxide. Specific copolymers include ethylene vinyl acetate copolymer (EVA), methyl ethylene acrylate copolymer, ethyl ethylene (meth) acrylate copolymer, ethylene (meth) acrylate copolymer, and ethylene propylene. Examples thereof include rubber (EPM) and ethylene propylene diene rubber (EPDM).

Low-density polyethylene has a short-chain branch and a long-chain branch in terms of molecular structure, and has a density of 0.910 g / cm ³ or more and less than 0.942 g / cm ³ , and typically has a density of 0.930 g / cm / cm. It is cm ³ or less. High-density polyethylene is polyethylene having few branches due to its molecular structure and a density of 0.942 g / cm ³ or more. In addition, polyethylene having a density of 0.930 g / cm ³ or more and less than 0.942 g / cm ³ may be referred to as medium density polyethylene.
The linear low-density polyethylene is generally a copolymer of ethylene and a small amount of α-olefin other than ethylene, and examples of the α-olefin other than ethylene include α-olefins having 3 to 10 carbon atoms. Specific examples thereof include propylene, butene-1, penten-1, 4-methyl-pentene-1, hexene-1, octene-1, and decene-1. The density of the linear low density polyethylene is less than 0.942 g / cm ³ , typically less than 0.930 g / cm ³ , and for example 0.880 g / cm ³ or more, typically 0.880 g / cm ^3. It is 0.910 g / cm ³ or more.

Ultra high molecular weight polyethylene (UHMWPE) is a polyethylene having a larger molecular weight than general polyethylene, for example, a polyethylene resin having a weight average molecular weight of 400,000 or more, preferably a weight average molecular weight of 1 million or more. The ultra-high molecular weight polyethylene has good mechanical strength due to the high weight average molecular weight. Further, the weight average molecular weight of the ultra-high molecular weight polyethylene is preferably 7 million or less, more preferably 4 million or less, from the viewpoint of easiness of polymerization. The weight average molecular weight is a standard polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC).
The ultra high molecular weight polyethylene (UHMWPE) may be an ethylene homopolymer, or may be a copolymer of ethylene and an α-olefin other than ethylene. The α-olefins other than ethylene are as described in the above LLDPE.

Ethylene can be polymerized in the presence of a radical initiator, for example, to form a polyethylene resin. The radical initiator includes, but is not limited to, an oxygen-based initiator such as an organic peroxide, a peroxy ester, a dialkyl peroxide, or a combination thereof. Specific examples of the radical initiator are not particularly limited, but are t-butylperoxypivalate, di-t-butylperoxide (DTBP), t-butylperoxyacetate (TBPO), and t-butylperoxy-2-ethylhexano. Includes ate, t-butylperoxyneodecanoate (PND), t-butylperoxyoctoate, and any combination of two or more of these.

Ethylene can also be made into a polyethylene resin by polymerizing in the presence of a catalyst such as a redox catalyst. Examples of the redox catalyst include Ziegler-Natta catalyst, metallocene catalyst, Philips catalyst, standard catalyst and the like.

As the Ziegler-Natta catalyst, for example, a triethylaluminum-titanium tetrachloride solid composite is used. The Ziegler-Natta catalyst is, for example, a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound and further treating it with various electron donors and electron acceptors, an organoaluminum compound, and an aromatic. It may be combined with a carboxylic acid ester, or titanium halide may be brought into contact with titanium tetrachloride and various electron donors to form a supported catalyst.
Examples of the metallocene catalyst include compounds such as a bis (cyclopentadienyl) metal complex having a structure in which a transition metal is sandwiched between π-electron unsaturated compounds. More specifically, one or more cyclopentadienyl rings or their analogs are present as ligands in tetravalent transition metals such as titanium, zirconium, nickel, palladium, hafnium, and platinum. Examples of the compound.
The Ziegler-Natta catalyst and the metallocene catalyst may be used in combination with specific co-catalysts (co-catalysts). Specific examples of the co-catalyst include methylaluminoxane (MAO) and boron-based compounds.

The Phillips catalyst is, for example, a catalyst system containing a chromium compound such as chromium oxide. Specifically, solid oxides such as silica, alumina, silica-alumina, and silica-titania are combined with chromium trioxide, chromic acid ester, and the like. An example of a catalyst carrying the chromium compound of.
The standard catalyst is a known catalyst using molybdenum oxide, and examples thereof include gamma-alumina and molybdenum oxide.

As an ethylene polymerization method, a high pressure method can be mentioned when a radical initiator is used. In the high pressure method, ethylene may be polymerized in an environment of 1000 to 4000 atm and 100 to 350 ° C. using, for example, a multi-stage gas compressor. Then, the residual monomer is separated and cooled to obtain it. Ethylene can be produced by the high pressure method to produce low density polyethylene (LDPE).

When using catalysts such as Ziegler-Natta catalysts, metallocene catalysts, Philips catalysts, and standard catalysts, ethylene should be polymerized by the low pressure method or medium pressure method. When these catalysts are used, it is preferable to use any of a liquid phase polymerization method, a gas phase polymerization method, and a suspension polymerization method. HDPE can be produced by polymerizing ethylene by a low pressure method or a medium pressure method using these catalysts. LLDPE can also be produced by copolymerizing ethylene with a small amount of α-olefin other than ethylene using these catalysts. Further, for example, an ultra-high molecular weight polyethylene can be obtained by carrying out polymerization for a long period of time by a low-pressure suspension polymerization method.

The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Manufacturing of raw material ethanol>
(Raw material gas generation process)
The gas discharged after burning general waste in a waste incineration facility was used. The components of the raw material gas were about 30% by volume of carbon monoxide, about 30% by volume of carbon dioxide, about 30% by volume of hydrogen, and about 10% by volume of nitrogen.

(Syngas purification process)
Under the condition that the raw material gas produced above is heated to 80 ° C. using a pressure swing adsorption type separator (PSA), the carbon dioxide contained in the synthetic gas is 60. After removing ~ 80% by volume, recool using a double-tube heat exchanger using steam at 150 ° C to raise the gas and using a double-tube heat exchanger using cooling water at 25 ° C. A synthetic gas was produced by precipitating impurities and removing the precipitated impurities with a filter.

(Ethanol conversion process)
Inoculum of Clostridium autoethanogenum (microorganism) equipped with a main reactor, synthetic gas supply hole, and discharge hole, and a liquid medium for culturing the bacteria (including appropriate amounts of phosphorus compound, nitrogen compound, various minerals, etc.) The synthetic gas obtained as described above was continuously supplied to the filled continuous fermentation apparatus (microbial fermentation tank), and culturing at 37 ° C. (microorganism fermentation) was continuously carried out for 300 hours. Then, about 8000 L of the culture solution containing ethanol was extracted from the discharge hole.

(Separation process)
The ethanol-containing culture solution obtained in the above ethanol conversion step is solid-liquid separated using a solid-liquid separation filter device under the conditions of a culture solution introduction pressure of 200 kPa or more and a temperature of 37 ° C. to obtain an ethanol-containing solution. It was.

(Pre-stage purification process)
Subsequently, the ethanol-containing liquid was introduced into a distillation apparatus equipped with a heater using steam at 170 ° C. After raising the temperature of the bottom of the distillation column to 101 ° C. within 8 to 15 minutes, the ethanol-containing liquid was introduced from the center of the distillation column, and during continuous operation, the bottom of the column was 101 ° C. and the center of the column was 99 ° C. The crown was continuously operated at 91 ° C. under the condition of 15 seconds / L to obtain purified ethanol. The pressure inside the distillation column was 60 to 95 kPa (absolute pressure). The purified ethanol (raw material ethanol) had an ethanol purity of 90% by volume or more.

(First purification step)
The obtained ethanol is purified by reverse phase chromatography to remove mainly aliphatic saturated hydrocarbons having 6 to 14 carbon atoms.

(Ethylene production process)
A product containing ethylene is produced from the raw material ethanol purified in the first purification step.
Specifically, the reaction tube is filled with an activated alumina catalyst, and the temperature is adjusted to 525 ° C. and the pressure is adjusted to 0.5 MPaG. The ethanol obtained in the first purification step is supplied to the reaction tube and subjected to a vapor phase dehydration reaction to produce an ethylene-containing product containing ethylene.

(Second purification step)
A first condenser cooled to 5 ° C., a second condenser cooled to −70 ° C., and a third condenser cooled to −170 ° C. were arranged in this order, and the ethylene-containing product produced above was added thereto. Purified ethylene is produced by sequentially bubbling the products. The first condenser removes mainly water, the second condenser mainly removes unreacted ethanol, 2-propanol and diethyl ether, and the third condenser mainly removes propylene and carbon monoxide. And remove oxygen.

(Manufacturing of polyethylene resin)
After substituting the reaction tube with nitrogen, the co-catalysts modified methylaluminoxane (MMAO), Ziegler-Natta catalyst, and toluene are added. After stirring at room temperature under normal pressure, the temperature is raised to 50 ° C., ethylene is supplied and polymerization is carried out to produce a polyethylene resin (HDPE).
By going through the first and second purification steps, the polyethylene produced in this example can preferably proceed with the polymerization activity in the ethylene polymerization reaction, and can improve the quality of the obtained polymer. For comparison, polyethylene polymerized using commercially available high-purity ethylene can have the same molecular weight.

Claims

An ethylene production process for obtaining an ethylene-containing product containing ethylene from raw material ethanol containing ethanol derived from waste.
It comprises at least one of a first purification step of purifying the raw material ethanol prior to the ethylene production step and a second purification step of purifying the ethylene-containing product after the ethylene production step.
Ethylene production method.
The first purification step is carried out from the raw material ethanol by an aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms, an aliphatic saturated hydrocarbon having 3 to 14 carbon atoms, an alcohol having 3 to 10 carbon atoms, and 3 to 3 carbon atoms. The method for producing ethylene according to claim 1, which comprises removing at least one selected from the group consisting of 10 ethers.
The second purification step is performed on the ethylene-containing product from an aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms, an aliphatic saturated hydrocarbon having 3 to 14 carbon atoms, an alcohol having 3 to 10 carbon atoms, and 3 carbon atoms. The method for producing ethylene according to claim 1 or 2, which comprises removing at least one selected from the group consisting of ether, carbon monoxide, and oxygen of -10.
The method for producing ethylene according to claim 2 or 3, wherein the aliphatic unsaturated hydrocarbon having 3 to 14 carbon atoms contains propylene.
The method for producing ethylene according to any one of claims 2 to 4, wherein the aliphatic saturated hydrocarbon having 3 to 14 carbon atoms contains an aliphatic saturated hydrocarbon having 6 to 14 carbon atoms.
The method for producing ethylene according to any one of claims 2 to 5, wherein the alcohol having 3 to 10 carbon atoms contains 2-propanol.
The method for producing ethylene according to any one of claims 2 to 6, wherein the ether having 3 to 10 carbon atoms contains dibutyl ether.
A method for producing a polymer, which comprises a polymerization step of polymerizing a monomer containing ethylene produced by the method according to any one of claims 1 to 7 to obtain a polymer.