JPS6123688A - Production of hydrocarbon mainly composed of lower saturated aliphatic from synthesis gas - Google Patents

Abstract

PURPOSE:To produce a hydrocarbon mixture rich in lower paraffins in a good yield with one-stage reaction, by using zeolite having a specified pore size as a methanol convertion catalyst in the titled method using a catalyst mixture of a methanol synthesis catalyst and a methanol conversion catalyst. CONSTITUTION:A synthesis gas is catalytically treated by using a catalyst mixture (or pellet) obtd. by physically mixing a methanol synthesis catalyst (A) (e.g. CuO-ZnO-Al2O3 catalyst or Pd-SiO2 catalyst) with a methanol conversion catalyst (B) composed of zeolite having an average pore size of 10Angstrom or above [e.g. Y type zeolite (which has been subjected to an aluminum removal treatment or steam treatment)]. Pref. the treatment is carried out under such conditions that the temp. is 250-450 deg.C, the pressure is 5-100kg/cm<2> and the H2/CO ratio of the raw synthesis gas is 4-1.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a mixed gas of hydrogen and carbon monoxide generated from a water gas reaction of coal, a partial oxidation reaction, a steam reforming reaction of natural gas, etc. Regarding the method of producing hydrocarbons by reacting gas in the presence of a catalyst, it is a method for directly obtaining mixed hydrocarbons mainly composed of lower saturated aliphatics through a one-step reaction. A hydrocarbon mixture having a composition similar to this can be produced to provide something that can be used extremely effectively as a fuel.

(Energy Situation) Recently, the demand for petroleum energy has stabilized for the time being.
Although its price has stabilized, considering the finite nature of oil reserves, there is an urgent need to develop alternative energy sources.

However, social acceptability of nuclear fission energy is limited due to its safety and environmental issues, and although fusion energy has high expectations as a future technology, its realization is still a long way off.

Furthermore, although solar energy, biomass, etc. are ideal as renewable energy resources, their supply density is sparse and variable, and there are technical difficulties in their concentrated, large-scale use.

Therefore, other than nuclear fission, the most realistic energy alternative to oil for the time being is unused fossil fuel resources such as coal, oil shale, and oil sands.

Additionally, ``Currently, LPG, whose main components are propane and butane, has become an indispensable fuel for people's lives.
Demand has increased in developing countries in recent years, but L
PG itself is essentially a by-product of oil refining, and is not intended as an oil substitute, and its supply itself is not necessarily stable.

Therefore, by gasifying the above-mentioned fossil fuel or unused biomass to obtain synthesis gas, and reacting this on a suitable catalyst, lower aliphatic saturated hydrocarbons such as LPG, that is, lower paraffins can be selectively synthesized. If so, fossil fuel resources can be used extremely effectively, and the finite nature of oil resources can also be addressed.

(Conventional technology for producing hydrocarbons from synthesis gas and its problems) The Fischer Nitrobusch process is a well-known method for producing hydrocarbons from synthesis gas, but its products range from methane to wax. It is difficult to selectively obtain specific components or components within a certain boiling point range.

In addition, by utilizing the previous knowledge that zeolites convert methanol into hydrocarbons, we first convert synthesis gas into methanol, and then convert this methanol into C3 to CIO using a zeolite catalyst called ZSM-5 (a trademark of Mopil Corporation). However, since this method is a two-step process, energy loss is large, and the product also contains a large amount of aromatic hydrocarbons, so it is not suitable as a method for selectively synthesizing lower paraffins. It's not appropriate.

Furthermore, there has been an attempt to directly generate hydrocarbons from synthesis gas using a physical mixed catalyst of a methanol synthesis catalyst and this ZSM-5, but the product is a C1-C4 aliphatic system and a C6-C11 aliphatic system. It is difficult to selectively obtain only lower aliphatic hydrocarbons, and the reaction conditions are 427°C, 83atm.
This shows a severe value.

Therefore, two of the present inventors, in collaboration with others, developed a palladium catalyst (Pcl/Sin) supported on silica gel, etc.
By using a mixed catalyst consisting of a zeolite catalyst such as ZSM-5 (i.e., methanol synthesis catalyst) and a zeolite catalyst such as ZSM-5 (i.e., methanol conversion catalyst), hydrocarbons can be removed from synthesis gas in one step under mild reaction conditions. The invention for synthesis (hereinafter referred to as the "Invention A") was first applied for (Japanese Patent Application Laid-Open No. 1983-1983)
(See No. 494).

However, the purpose of this invention is to limit the methanol synthesis catalyst to a specified palladium catalyst, produce aromatic-rich hydrocarbons, and thereby obtain a gasoline fraction with a high octane number. , it is not intended for the production of fuel mainly composed of lower paraffins.

(Another Means to Solve the Problem) The present inventors have discovered that in a method for synthesizing hydrocarbons from synthesis gas in the presence of a mixed catalyst of a methanol synthesis catalyst and a zeolite catalyst, the distribution of the generated hydrocarbons is The present invention was newly discovered based on this discovery, and the present invention was completed based on this discovery.

That is, in the present invention, synthesis gas is reacted in the presence of a mixed catalyst in which a methanol synthesis catalyst and a methanol conversion catalyst made of zeolite having an average pore size of about 10 Å or more are physically mixed to produce lower-grade compounds such as propane and butane. A method for mainly producing paraffin is provided.

The above-mentioned methanol synthesis catalyst is mainly composed of a metal or a metal oxide, and contains an 0r-Zn-based or Cu-Zn-based catalyst (specifically, a CuO-Zn0=A1203 catalyst), or a carrier such as silica gel, alumina, magnesia, or calcia. A catalyst having an active metal such as palladium, platinum, or nickel supported thereon (specifically, a P d/S 102 catalyst) may also be used.

Furthermore, the methanol conversion catalyst is a zeolite having an average pore diameter of approximately 10 Å or more, and specifically, the artificial pore diameter is 7.4 Å.
A Y-type zeolite with a pore size of 13 mm and a supercage diameter is more preferred, and can be used directly as is or treated with dealumination, steam treatment, or EDTA.
The methanol conversion characteristics may be changed as desired by chemical treatment with or the like.

Moreover, the activity of the above-mentioned methanol conversion catalyst remains relatively unchanged even after long-term use, but the zeolite catalyst tends to lose its activity, so using a mixture of both catalysts leads to an improvement in reaction efficiency, Even the main body of the mixed powder may be press-molded.

On the other hand, the present invention conducts the synthesis reaction at 250-450°C, 5-
It is preferable to carry out within the range of 1-00 kg/cm2. That is, at temperatures below 250°C, the methanol conversion reaction by the zeolite catalyst is difficult to occur, and conversely, at temperatures above 450°C, the selectivity of methane among lower paraffins increases.

Further, if the amount is less than 5 kg/cm2, the methanol synthesis catalyst will not function, so the conversion of synthesis gas to methanol will not be achieved.On the other hand, if it is more than 100 kg/cm2, the plant construction cost will inevitably increase.

Further, the contact time W/F is preferably in the range of 1 to 20, and 1
If it is less than 20, the reaction cannot be promoted satisfactorily due to insufficient contact time with the catalyst, and if it is more than 20, the plant itself should be enlarged.

In addition, the mixing ratio H2/CO of the synthesis gas is preferably 4 to 1,
When it is 4 or more, the selectivity for methane etc. increases, and conversely, when it is 1 or less, the reaction rate becomes low.

(Reaction mechanism) Here, in the reaction to produce hydrocarbons from synthesis gas in the presence of a mixed catalyst, the mechanism can be summarized as shown in the figure below.2 First, synthesis gas CO + H2 is a methanol synthesis catalyst, For example, by the action of Pd/SiO2 catalyst, methanol CH30
This methanol is adsorbed into the pores of zeolite, which is a methanol conversion catalyst, to produce trimethyl ether CH30CH, see reaction (2)>, and after undergoing an irreversible reaction (3), becomes lower olefin CnH2n. .

In other words, the methanol synthesis reaction (1) is a reversible reaction and is not thermodynamically advantageous, which causes a decrease in its high-temperature activity, whereas the olefin production reaction (3) is a thermodynamically large reaction. It is advantageous for the reaction (
Since the methanol concentration decreases due to 2) and (3), the equilibrium of (1) tilts to the right and methanol is produced smoothly.

Therefore, mixing a methanol synthesis catalyst and a methanol conversion catalyst has the great advantage of eliminating thermodynamic limitations.

(y Underbody white) The olefin thus produced exits into the gas phase outside the zeolite depending on the pore size of the zeolite, and P d/S
There are two cases: i) when it is affected by the O2 catalyst, and when it is retained in the zeolite and is affected by the zeolite catalyst.

That is, zeolite with a small pore size, for example, the Z
In SM-5 and mordenite (5.5 x 5° 1 person, 7 x' 6.7 A, respectively), the diffusion of olefins in the pores is not fast, so many of the olefins stay for a long time,
Furthermore, since the pore size is a molecular size that is suitable for producing aromatic hydrocarbons, the methanol CH30H adsorbed within the pores undergoes a polycondensation reaction with this olefin on the zeolite, producing methyltribenzenes e(CH3). ,,
That is, a gasoline fraction is produced (see equation (5)).

Furthermore, the olefins diffused outside the pores are hydrogenated by the action of the methanol synthesis catalyst to produce 02 and C3 paraffins, but the selectivity within hydrocarbons is not necessarily high.

Incidentally, the above-mentioned Invention A utilizes this technical idea.

On the other hand, in zeolites with large pore diameters, such as Y-type zeolites (inlet pore diameter of 7.4 pores, super cage diameter of 13 pores),
The lower olefins quickly diffuse through the zeolite pores, enter the gas phase outside the zeolite, and undergo hydrogenation by the hydrogen in the synthesis gas on the methanol synthesis catalyst (which is also a high-quality hydrogenation catalyst). , which mainly produces lower paraffins of 01 to C5 (see formula (4))>.

For this reason, the olefin undergoes a condensation reaction within the zeolite Y catalyst to hardly give aromatic hydrocarbons, and the selectivity of lower paraffins among the generated hydrocarbons becomes extremely high.

The present invention utilizes this technical idea.

(Example) Examples will be described below in which a mixed catalyst of a methanol synthesis catalyst and a zeolite catalyst with a large pore size is reacted with synthesis gas under various conditions.

<Example 1> Reaction results were investigated using a Pd/5in2 catalyst as a methanol synthesis catalyst and various zeolites with different pore sizes as methanol conversion catalysts.

First, the methanol synthesis catalyst was prepared by impregnating silica gel with palladium chloride prepared from an acidic aqueous solution using the dry amplifier method, and then flowing hydrogen at 450°C for 2 hours to form a reduced state of Pd.
was generated.

The above-mentioned zeolite used was ZSM-5 manufactured by Mobil Corporation as a small pore size (5 to 7 pores) and two types of mordenite (trademark Zeolon; H-M (A) and H-H (B)), and H-Y as Y-type zeolite with large pore diameter (8~3 pores)
and REV were used.

H-Y is a proton type Y zeolite obtained by drying Linde type 5K-40 treated with ammonium chloride aqueous solution five times at 120°C for 20 hours and then calcining it at 450°C for 3 hours. .

Moreover, REY was obtained by calcining Linde type 5K-500 at 450° C. for 3 hours.

Then, one methanol synthesis catalyst and various zeolite catalysts were added.
:1 weight ratio, pulverized to 80 mesh or less, press-molded at a pressure of 200 kg/cm2, and finally finely pulverized to 20 to 40 mesh to prepare a mixed catalyst.

Next, this mixed catalyst was placed in a pressure-resistant fixed bed flow reactor and activated by flowing hydrogen at 450°C for 2 hours.
Molar ratio (H2/Co) 1/2, contact time (W/F)
Each mixed catalyst was reacted by flowing it into the reactor under conditions of 10 g-cat .I+r/mol, and the results shown in Figure 1 were obtained.

Note that the components of the product were obtained by directly analyzing the outlet gas of the reactor using a gas chromatograph.

According to Chart 1, zeolite with small pore size)<ZSM-5
, HM(A), HM(B)>, the selectivity of ethane, propane, and aromatic hydrocarbons is high, and in particular, ZSM-
In No. 5, the aromatic selectivity (mainly composed of tetramethylbenzene) reached 30.6%. Furthermore, the overall selectivity of butane among aliphatic compounds is low, remaining at about 5 to 7%.

On the other hand, zeolites with extraordinary pore sizes (H-Y, RE
In V), a mixture of lower paraffins such as ethane, propane, and butane is mainly provided, and the selectivity of these LPG components is 7.
0 to 80%, but no aromatic hydrocarbon formation is observed.

Therefore, this example demonstrates that changing the pore size of the zeolite catalyst causes a change in the distribution of hydrocarbons, but it is also demonstrated that increasing the zeolite pore size can suppress the production of aromatic hydrocarbons. C4-C6, especially C2-
C117) It can be seen that lower paraffins can be synthesized with high selectivity.

<Example 2> Using Y-type zeolite subjected to various treatments, the reaction results were investigated.

That is, as a methanol synthesis catalyst, P d/S! 0
In addition, a mixed catalyst was prepared using various Y-type zeolites as a meta-7-al conversion catalyst, and in the presence of this mixed catalyst, synthesis gas H2+CO was heated at 350°C12, OK.
g/cm', H2/CO=]/2, W/F=108-
The reaction was carried out under the conditions of cat'hr/+nol.

As the Y-type zeolite, HY (used in Example 1), DAY, and 5L-DAY were used, respectively.

DAY is dealuminated zeolite manufactured by Catalysts Kasei Co., Ltd.
SiO2/A+203=7.6) r, defluorination [compared to the normal H-Y which is not filled with L and has a value of Si○, /Al2O325.1, the Brønsted acid and α are stronger. ing.

This can also be seen from the fact that, as is clear from Figure 1, when zeolite is dealluminized, the temperature-programmed desorption peak of @adsorbed ammonia appears on the high temperature side of approximately 350°C, creating strong acid sites. .

In addition, S t -D AY is the above DAY at 450°C.
The coke (carbonaceous material on the catalyst) production ability is significantly reduced.

Chart 2 shows the results of this example, and in both cases propane and butane are provided with relatively high selectivity, but DAY
When using H-Y, the hydrocarbon yield was more than double (6.5 → 14.6%), indicating that the paraffin-forming activity of DAY was extremely high. .

Furthermore, when 5L-DAY is used, the yield of hydrocarbons is approximately twice that of H-Y, and the selectivity of propane and butane increases dramatically to a total of 68% (43→ 6
8%).

Furthermore, when using this 5t-DAY, what appears particularly remarkable compared to H-Y is a characteristic decrease in methane selectivity (12,6 → 5.0%), which suppresses methane production. has important significance in improving the energy efficiency of the reaction.

In other words, in the synthesis gas reaction, the product is condensed and liquefied, separated into various fractions, and the unreacted synthesis gas fraction is recycled to the reactor, but the boiling point of methane is lower than the unreacted hydrogen and monoxide. Since it is close to the boiling point of carbon, it is difficult to separate the synthesis gas and methane, and as a result, the methane fraction is also recycled, and as the reaction progresses, methane accumulates in the reaction vessel.

Therefore, in order to improve the conversion rate, the removal of this stored methane is a major issue, and it is necessary to incorporate methane removal equipment separately into the reactor, or to perform a process of steam reforming of methane (CH, +
It is conceivable to add H2O-+CO+3H2) to convert it into the reactant synthesis gas, but in any case, the energy loss is large and the increase in methane selectivity in the product is not favorable for the energy cost of the reaction plant. be.

Therefore, if the 5t-DAY is applied to the hydrocarbon production reaction, the selectivity of methane can be made extremely low, and the energy loss required for methane removal can be minimized.

Incidentally, as mentioned above, the acidity-adjusted Y-type zeolite is within its own catalytic activity temperature range (300 to 400'C
) has a high acid point (the acid point peak is approximately 3
After the polymerization was accelerated to some extent by the zeolite catalyst, the olefin could be desorbed into the gas phase, that is, on the methanol synthesis catalyst side. It is presumed that by increasing the selectivity of paraffins (with a higher degree of polymerization), it is possible to suppress the production of methane.

As described above, when Y-type zeolite, which is a general large-pore zeolite, is subjected to dealumination treatment to change its acid properties, the methanol conversion characteristics can be improved in a favorable direction, such as improving paraffin conversion and methane selectivity. can be changed in the direction of reducing the

<Example 3> Using a Pd/SiO2+5t-DAY mixed catalyst, the temperature was lowered to 270°C under the same conditions as Example 2 (excluding temperature).
As a result of actually measuring the selectivity of hydrocarbon products by changing the temperature to 320°C, 320°C, and 370'C, Figure 2 was obtained.

According to the same figure, it can be seen that the selectivity of propane and butane is maximum over a wide range of 270°C to 370°C (when both are combined, each temperature shows a range of approximately 60% to 65%). .

<Example 4> Using a Pct/S io, + S t -D AY mixed catalyst, the product was As a result of actually measuring the yield and hydrocarbon distribution, Figure 3 was obtained.

According to the figure, pressure and product yield are proportional, but the distribution of hydrocarbons does not change much at pressures above 20 atm.

<Example 5> Using a P d / S i O 2 + S t D AY mixed catalyst, the temperature was changed from 250 to 350 °C under the same conditions as in Example 2 (except for the temperature) to produce Figure 4 was obtained as a result of actually measuring the yield of the product and the distribution of hydrocarbons.

According to the figure, temperature and product yield are proportional, but charcoal]b
The hydrogen distribution shows a maximum value in the temperature range of 270-340'C.

<Examples> Using a Pd/5in2+St DAY mixed catalyst, the product was collected under the same conditions as in Example 2 (excluding the contact time) and changing the contact time W/F to 308 cat ・t+r/mol. As a result of actually measuring the ratio and distribution of hydrocarbons,
Figure 5 was obtained.

According to the figure, the product yield is proportional to the contact time, but the distribution of hydrocarbons does not change much with changes in the contact time.

<Example 7> Chart 3 was obtained as a result of performing the reaction in the presence of a mixed catalyst in which the methanol conversion catalyst was 5L-DAY and the methanol synthesis catalyst was varied in various ways.

The methanol synthesis catalyst is Pd/5in3.2 types of Cu
-Zn<Cu-Zn(A) and (B)> and Z
Using n-Cr, 20kg/cm2, H2/C0=1/
In No. 2, the contact time W/F was changed as appropriate.

Cu-Zn (A) is obtained by hydrogen-treating a homemade copper-zinc-alumina mixed oxide catalyst at 300°C, and
u-Zn(B) is a commercially available low-pressure methanol synthesis catalyst.
It was obtained by hydrogen treatment at 00°C.

However, in the case of a Cu--Zn catalyst, the temperature is 300° C. due to its durability.

According to Chart 3, instead of Pd/5in2 catalyst, Cu-
When a Zn-based catalyst is used (Takashi Cu-Zn(A), W/F
- It can be seen that the hydrocarbon yield (except for the combination of '2' and 7) is significantly improved (6.4 → 36.0.35.7
%).

In addition, for two types of C'u Zn-based catalysts, the temperature was set to 300
℃, the methane selectivity decreases to 1 to 2% compared to the results shown in Examples 1 and 2 at a reaction temperature of 350 to 370℃, while the ethane selectivity decreases to 7 to 11%.
It can be seen that the selectivity of propane and butane has improved to about 66 to 75% in total.

It can be assumed that the increase in the average molecular weight of the produced hydrocarbons due to this decrease in temperature is because the adsorption of the produced lower olefins becomes more advantageous, making it easier for the low molecular weight polymerization reaction to proceed.

Furthermore, at this low temperature, the selectivity for aliphatic hydrocarbons of C5 or higher also increases (1), but the production of aromatic hydrocarbons is virtually not observed.

Then, the above St-, DAY+Cu-Zn(A)(W/
F = 10.3) The selectivity of hydrocarbons when using a catalyst is compared with the conventional production method, that is, ZSM? 5+ methanol synthesis catalyst, Fe-Mn-Cr-based Fischer nitro-Bush catalyst, and maximum LP.
When each is compared with the distribution function calculated from the 5chulz-Flory law that gives the G component and graphed, FIG. 6 is obtained.

According to the figure, the conventional method and S cl+ulz −F
The selectivity of any of the lory functions decreases as the number of carbon atoms in the hydrocarbon increases, but in this example, the selectivity of propane and butane is high, and in particular, the selectivity of butane shows the maximum value. , the resulting mixed hydrocarbon is optimal as a fuel.

In addition, when using a Zn-Cr catalyst, the selectivity of propane and butane decreases compared to a Pd/Sin2 catalyst.
→47%), and conversely, the methane selectivity increases (1.1 → 7%).
．． 0%), therefore, under these reaction conditions, the Zn-Cr catalyst does not have a very high function as a catalyst for synthesizing 7-l.

In addition, in this example, no matter which catalyst system is used, carbon dioxide is produced in an amount comparable to that of hydrocarbons, but this is because water produced with hydrocarbons undergoes a CO shift reaction with unreacted carbon monoxide. (CO+H2O-1co, +H
7) If an appropriate amount of CO2 is allowed to coexist during the synthesis process, its by-product can be controlled.

On the other hand, as mentioned above, Cu with high LPG production activity
-Zn-based catalysts produce some reaction intermediates such as methanol and dimethyl ether, but by increasing the mixing ratio of the zeolite catalyst, the production of these reaction intermediates can be suppressed.

That is, according to Chart 4, when the mixing ratio of methanol synthesis catalyst and zeolite catalyst is changed from 171 to 11'3,
It can be seen that the yield of methanol is reduced from 3.9% to a trace amount, and the yield of dimethyl ether is also reduced from 0.5% to a trace amount.

<Example 8> As a result of using a Cu-Zn-based catalyst showing good LPG production activity as a methanol synthesis catalyst and variously changing the methanol conversion catalyst, that is, the Y-type zeolite catalyst, the reaction was carried out.
Figure 5 was obtained.

Incidentally, among the zeolite catalysts, REV is the same as that used in Example 1, and Pt-Y is I4 on which Pt is supported.

According to the above table, 5t treated at a steam treatment temperature of 600℃
-DAY, the yield of the hydrocarbons produced is very low (2.0%), but in other cases the yields are not very different (15,
0-20.3%).

However, the distribution of hydrocarbons differs depending on each reaction condition, and when 5L-DAY obtained by treatment with steam at 400°C was used and the reaction was performed at a steam treatment temperature of 400°C, the methane selectivity was low (1 ,8%), conversely, propane,
and butane 1. That is, the LPG selectivity reached a maximum value of 77%.

When the 5t-DAY catalyst is used, it can be seen that when the steam treatment temperature is gradually increased to 600°C, the methane selectivity increases and the LPG selectivity decreases.

In addition, when using PL-Y and REV, 5c-D
A. Purchased steam treatment temperature: 400°C) Compared to the case of a catalyst,
The methane selectivity decreases, and in particular, Pt-Y shows a minimum value of 0.9%, or the LPG selectivity decreases slightly (excluding the case of the 5t-DAY catalyst with a steam treatment temperature of 600°C).

Therefore, by using the Cu-Zn 15t-DAY catalyst and suppressing the steam treatment temperature to 400°C, the methane selectivity is reduced and the LPG selectivity is 77%, which is a high level that could not be achieved in each of the above examples. Value can be realized.

Moreover, when the Pv-"1' catalyst is used, the methane selectivity is kept at 0.9%, which is extremely low compared to any of the above examples, so the methane purge operation can be practically ignored. .

The results of Examples 1 to 8 thus obtained are summarized below.

(1) When the pore size of the zeolite catalyst changes, the distribution of hydrocarbons also changes.

When a zeolite catalyst with a large pore size (for example, Y-type zeolite) is used, it is possible to suppress the production of aromatic and aromatic hydrocarbons and synthesize lower paraffins ranging from C1 to C6 with extremely high selectivity (Figure 1). reference).

(2) Methanol conversion characteristics can be changed by subjecting large-pore zeolite to dealumination treatment and/or steam treatment to change acid properties.

That is, the yield of lower paraffins can be increased by using a large-pore zeolite catalyst that has been treated with dealumination to increase its acidity.

Furthermore, if the degree of hydration is increased by further steam treatment after the deamidation treatment, the selectivity of methane can be reduced while maintaining a high hydrocarbon yield (see Figure 2).

Therefore, by using the zeolite catalyst, it is possible to easily suppress the production of methane, which causes a large amount of energy loss in the synthesis process.

(3) In the method of synthesizing lower paraffins using this mixed catalyst, it is preferable to set the reaction temperature to approximately 270 to 370°C and the pressure to approximately 10 to SOatm (Section 2.3).
and Figure 4).

In addition, the product yield is proportional to the contact time W/F,
An increase in W/F leads to an increase in product yield, but the distribution of produced hydrocarbons does not change significantly even with changes in W/F, so if the energy efficiency of the plant is considered, W/F will increase.
It is preferable to keep F below 20 (see Figure 5).

(4) Among mixed catalysts, as a methanol conversion catalyst -
When using a certain catalyst (for example, 5t-DA'l' catalyst) and changing the methanol synthesis catalyst to a Pd/SiO2 catalyst, a Cu-Zn catalyst, or a Zn-Cr catalyst, the resulting hydrocarbon yield increases. Change significantly.

When a Cu-Zn catalyst is used as the methanol synthesis catalyst, lower paraffins can be obtained in high yield.

Moreover, the Cu-Zn catalyst becomes sand active at a relatively low temperature of approximately 30.0,'(:'), has a low methane selectivity (1-2%) in the hydrocarbon distribution, and a high LP
It has a G selectivity (70-75%) (see Figure 3).

(5) Therefore, if (1) to (4) are taken together, in order to increase the LPG selectivity while suppressing the methane selectivity, C
u-Zn catalyst (methanol synthesis catalyst) and 5t-DAY
In the presence of a mixed catalyst consisting of a combination of catalysts (methanol conversion catalyst), 300°C, 10 to 50 atm, W/F = 2
It is optimal to react the synthesis gas under reaction conditions of 0 or less.

(Effects of the Invention) As described above, the present invention is a method for producing mixed hydrocarbons rich in lower paraffins from synthesis gas using a mixed catalyst that is a combination of a zeolite catalyst with a large pore size and a methanol synthesis catalyst, and has the following effects. have

(1) By reacting synthesis gas in the presence of this mixed catalyst, it is possible to directly obtain a mixed hydrocarbon rich in lower paraffins in a one-step reaction. There is no need for a two-step reaction operation to convert it into .

Therefore, the energy efficiency of the reactor can be economically reduced, and the reaction can be carried out quickly to eliminate the complexity of operation.

(2) The present invention uses synthesis gas that can be easily obtained from fossil fuels or unused biomass as a raw material, and the resulting hydrocarbons mainly contain lower paraffins, particularly propane and butane (i.e., LPG components). Because it is rich in minerals, it can be used effectively as fuel, and today, when the finite nature of petroleum is being pointed out, it is extremely needed as a realistic alternative energy to petroleum.

(3) The present invention is characterized by the use of a zeolite catalyst with a large pore size, but if this zeolite catalyst is limited to one that has been subjected to dealumination treatment or steam treatment to adjust the acidity, it will not be possible to obtain benefits. The distribution of hydrocarbons is
It is rich in propane and butane, and the selectivity of methane can be suppressed to a low level, making it particularly excellent as a fuel. Furthermore, there is no need to add various methane purge equipment to the reaction apparatus, and energy loss in the entire apparatus can be largely eliminated.

(4) The present invention can be applied under a wide range of reaction conditions using a methanol synthesis catalyst and a zeolite catalyst with a large pore size.
Lower paraffins can be provided under conditions such as ℃ and 20 atm, making the reaction more economical.

Furthermore, although zeolite catalysts are limited in pore size, they can be applied to the present invention as long as they satisfy this condition, regardless of changes in molecular structure and pore structure, or with or without various preparation treatments. As long as it has hydrogenation ability as an attribute, Pd-based, Cu-Zn-based, Cr-Zn
In addition to the system, various metals or metal oxides can be used singly or in combination, and a wide range of mixed catalysts can be selected to facilitate the implementation of the reaction.

[Brief explanation of the drawing]

Chart 1 shows the reaction results when changing the zeolite pore size, Chart 2 shows the reaction results when changing the acidity of zeolite, Chart 3 shows the reaction results when changing the methanol synthesis catalyst among the mixed catalysts, Chart 4 shows the reaction results when the catalyst mixing ratio is changed, and Chart 5 shows the reaction results when the methanol synthesis catalyst is changed to C.
The reaction results are shown when the zeolite catalyst is changed, limited to the u ---Z n-based catalyst. Figure 1 shows the relationship between temperature and ammonia desorption rate when the acidity of the zeolite catalyst is adjusted, and Figure 2 shows the relationship between temperature and ammonia desorption rate. Figure 3 shows the relationship between reaction pressure and activity selectivity, Figure 4 shows the relationship between reaction temperature and activity selectivity, and Figure 5 shows the relationship between contact time and product yield and formation. Figure 6 shows the distribution of hydrocarbons produced when the catalyst is changed.

Claims (1)

[Claims] 1. Existence of a mixed catalyst in which a methanol synthesis catalyst such as a Cu-Zn type, Cr-Zn type, or Pd type is physically mixed with a methanol conversion catalyst made of zeolite with an average pore size of approximately 10 Å or more. Below, method 2 for producing hydrocarbons from synthesis gas characterized by reacting synthesis gas consisting of hydrogen and carbon monoxide to mainly produce lower aliphatic saturated hydrocarbons, dealumination treatment and/or steam Claim 1 is characterized in that the selectivity of the methane produced is reduced by reacting synthesis gas in the presence of a mixed catalyst of zeolite whose acidity has been increased through treatment and a methanol synthesis catalyst. Method for producing hydrocarbons mainly composed of lower saturated aliphatics from the described synthesis gas