阅读说明：本技术 催化剂体系及其应用 (Catalyst system and use thereof ) 是由 赵清锐 王雪 韦力 冯静 张明森 刘东兵 于 2020-06-30 设计创作，主要内容包括：本发明涉及催化剂领域,公开了催化剂体系及其应用,在反应物流方向上,该催化剂体系依次包括第一催化剂段、填充段和第二催化剂段,其中,在反应物流方向上,所述填充段的长度为所述第一催化剂段与第二催化剂段的总长度的4-10倍；所述第一催化剂段中的催化剂和所述第二催化剂段中的催化剂相同或不同且各自独立地包括载体和负载在所述载体上的活性组分,其中,所述载体为CaO、MgO和BaO中的至少一种；所述活性组分为碱金属的氧化物；所述填充段中的填充物选自二氧化硅和/或氧化铝。提高甲烷转化率,提高碳二烃的选择性和收率,具有很好的工业化应用前景。(The invention relates to the field of catalysts and discloses a catalyst system and application thereof, wherein the catalyst system sequentially comprises a first catalyst section, a filling section and a second catalyst section in the direction of reactant flow, wherein the length of the filling section is 4-10 times of the total length of the first catalyst section and the second catalyst section in the direction of reactant flow; the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently comprise a carrier and an active component supported on the carrier, wherein the carrier is at least one of CaO, MgO, and BaO; the active component is an oxide of an alkali metal; the filler in the filling section is selected from silicon dioxide and/or aluminum oxide. The conversion rate of methane is improved, the selectivity and the yield of the carbon dioxide hydrocarbon are improved, and the method has good industrial application prospect.)

1. A catalyst system, characterized in that the catalyst system comprises a first catalyst section, a packed section and a second catalyst section in sequence in the direction of reactant flow, wherein the length of the packed section is 4-10 times the total length of the first catalyst section and the second catalyst section in the direction of reactant flow;

the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently comprise a carrier and an active component supported on the carrier, wherein the carrier is at least one of CaO, MgO, and BaO; the active component is an oxide of an alkali metal; the filler in the filling section is selected from silicon dioxide and/or aluminum oxide.

2. The catalyst system of claim 1, wherein the ratio of the lengths of the first catalyst section and the second catalyst section is from 1 to 4: 1, preferably 1-2: 1;

and/or the volume ratio of the first catalyst section to the second catalyst section is 1-4: 1, preferably 1-2: 1;

and/or the length of the filling section is 4.3-7.5 times of the total length of the first catalyst section and the second catalyst section.

3. The catalyst system of claim 1 or 2, wherein the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently further comprises a promoter which is at least one of an oxide of Sr, an oxide of La, an oxide of Y and an oxide of Sm;

preferably, the content of the auxiliary agent is 1 to 8g, preferably 2 to 4g, based on 100g of the carrier.

4. The catalyst system of claim 1, wherein the active component is at least one of an oxide of Li, an oxide of Na, an oxide of K, and an oxide of Rb;

and/or the content of the active component is 1 to 25g, preferably 3 to 20g based on 100g of the carrier.

5. The catalyst system of claim 1, wherein the first catalyst section is further provided with a first oxygen supplement inlet;

and/or the filling section is provided with a second oxygen supplement inlet;

and/or, the distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section in the reverse direction of the reactant flow is 0.5-0.9 times the length of the filling section.

6. A method for preparing a carbo-hydrocarbon by oxidative coupling of methane, the method comprising:

(1) sequentially filling a catalyst and a filler in a catalytic reactor along the reverse direction of a reactant flow to form a catalyst system comprising a second catalyst section, a filling section and a first catalyst section, wherein the length of the filling section is 4-10 times of the total length of the first catalyst section and the second catalyst section in the reactant flow direction;

the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently comprise a carrier and an active component supported on the carrier, wherein the carrier is at least one of CaO, MgO, and BaO; the active component is an oxide of an alkali metal; the filler in the filling section is selected from silicon dioxide and/or aluminum oxide;

(2) methane and oxygen are introduced into a catalytic reactor to contact with a catalyst to perform a catalytic reaction.

7. The process of claim 6, wherein the ratio of the lengths of the first catalyst section and the second catalyst section is from 1 to 4: 1, preferably 1-2: 1;

and/or the volume ratio of the first catalyst section to the second catalyst section is 1-4: 1, preferably 1-2: 1;

and/or the length of the filling section is 4.3-7.5 times of the total length of the first catalyst section and the second catalyst section.

8. The process of claim 6 or 7, wherein the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently further comprises a promoter which is at least one of an oxide of Sr, an oxide of La, an oxide of Y and an oxide of Sm;

preferably, the content of the auxiliary agent is 1 to 8g, preferably 2 to 4g, based on 100g of the carrier.

9. The method of claim 6, wherein the active component is at least one of an oxide of Li, an oxide of Na, an oxide of K, and an oxide of Rb,

and/or the content of the active component is 1 to 25g, preferably 3 to 20g based on 100g of the carrier.

10. The method of claim 6, wherein the first catalyst section is further provided with a first oxygen supplement inlet for introducing methane and first section oxygen into the catalytic reactor;

and/or the filler section is provided with a second oxygen supplement inlet so as to introduce second section oxygen into the catalytic reactor;

and/or, the distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 0.5-0.9 times of the length of the filling section along the reverse direction of the reactant flow.

11. The method as claimed in claim 10, wherein the temperature of the oxygen inlet point of the second-stage oxygen is 680-750 ℃, preferably 700-750 ℃;

and/or the volume ratio of the first section oxygen to the second section oxygen is 1-10: 1, preferably 4 to 10: 1.

12. the method of claim 6 or 11, wherein the volume ratio of methane to total oxygen input to the catalytic reactor is 2-6: 1, preferably 2.2 to 4: 1.

13. the method of claim 6, wherein the conditions of the catalytic reaction comprise: the reaction temperature is 680-800 ℃, preferably 700-750 ℃; the reaction pressure is 0-0.02MPa, the reaction time is 0.5-8h, and the hourly space velocity of the reaction gas calculated by methane and oxygen is 5000-.

Technical Field

The invention relates to the field of catalysts, in particular to a catalyst system and application thereof.

Background

In recent years, the natural gas exploration technology continuously makes a major breakthrough, a batch of large and medium-sized gas fields continuously emerge, the ascertained reserves and the output are rapidly increased, the proportion of natural gas in primary energy is gradually increased, and the chemical industry of natural gas gradually becomes one of the development directions of the petrochemical industry. In order to reduce the dependence on the production of olefins from petroleum resources, a technology for producing olefins from natural gas (mainly methane) as a carbon source has been a focus of research in recent years. Compared with indirect method, the technology for preparing olefin by methane direct method has short process flow and more economical energy consumption and equipment investment. Meanwhile, the method for preparing the olefin by the oxidative coupling of the methane (OCM) has more obvious advantages and industrial application prospects compared with other direct methods by considering the factors such as the yield of the olefin, the industrial feasibility and the like.

The catalyst for methane oxidation coupling reaction with better performance generally has good catalytic activity at the temperature of more than 700 ℃. The oxidative coupling reaction of methane is a strong exothermic reaction, so that a temperature runaway phenomenon is easily generated, and the problems of amplification of a reactor and heat removal in the reaction process are brought. If the heat in the process of the methane oxidative coupling reaction can be effectively controlled, the yield of C2 can be greatly improved, the energy consumption of the OCM reaction is reduced, and the method has good application prospect in industrial application.

Disclosure of Invention

The invention aims to overcome the problems that the heat generated by the methane oxidative coupling reaction is difficult to control and the temperature runaway phenomenon is easy to cause in the prior art, and provides a catalyst system and application thereof, wherein the catalyst is filled in two sections, the two sections of catalysts are separated by a filler, the length of the filler section is controlled to account for the total length ratio of the first catalyst section to the second catalyst section, and the two sections of catalysts are the same or different and respectively and independently comprise a carrier and an active component loaded on the carrier, wherein the carrier is at least one of CaO, MgO and BaO; the active component is an oxide of alkali metal to reduce the reaction temperature and disperse the reaction heat generated by the reaction system, thereby inhibiting the deep oxidation of methane to a certain extent, improving the selectivity and yield of the carbon dioxide hydrocarbon and having good industrial application prospect.

The inventor of the present invention found in research that, the catalyst system is packed in two sections, the two sections of catalysts are separated by the filler, and the length of the filler section is controlled to account for the ratio of the total length of the first catalyst section to the second catalyst section, and the two sections of catalysts are the same or different and respectively and independently comprise a carrier and an active component loaded on the carrier, wherein the carrier is at least one of CaO, MgO and BaO; the active component is an oxide of alkali metal, and can reduce the temperature of catalytic reaction, thereby inhibiting the deep oxidation of methane to a certain extent, improving the selectivity and yield of the carbon dioxide hydrocarbon, and having good industrial application prospect.

In order to achieve the above object, the present invention provides, in one aspect, a catalyst system comprising, in order in a reactant flow direction, a first catalyst section, a packed section, and a second catalyst section, wherein a length of the packed section is 4 to 10 times a total length of the first catalyst section and the second catalyst section in the reactant flow direction;

the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently comprise a carrier and an active component supported on the carrier, wherein the carrier is at least one of CaO, MgO, and BaO; the active component is an oxide of an alkali metal; the filler in the filling section is selected from silicon dioxide and/or aluminum oxide.

In a second aspect the present invention provides a process for the oxidative coupling of methane to produce a carbo-carburis, which process comprises:

(1) sequentially filling a catalyst and a filler in a catalytic reactor along the reverse direction of a reactant flow to form a catalyst system comprising a second catalyst section, a filling section and a first catalyst section, wherein the length of the filling section is 4-10 times of the total length of the first catalyst section and the second catalyst section in the reactant flow direction;

the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently comprise a carrier and an active component supported on the carrier, wherein the carrier is at least one of CaO, MgO, and BaO; the active component is an oxide of an alkali metal; the filler in the filling section is selected from silicon dioxide and/or aluminum oxide;

(2) methane and oxygen are introduced into a catalytic reactor to contact with a catalyst to perform a catalytic reaction.

The method for preparing the carbo-dydrocarbon by oxidative coupling of the methane has the advantages of low temperature of catalytic reaction, high conversion rate of raw materials, less side reaction, high selectivity and yield of the carbo-dydrocarbon, and easy large-scale production and application.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a catalyst system, which sequentially comprises a first catalyst section, a filling section and a second catalyst section in the direction of reactant flow, wherein the length of the filling section is 4-10 times of the total length of the first catalyst section and the second catalyst section in the direction of reactant flow;

the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently comprise a carrier and an active component supported on the carrier, wherein the carrier is at least one of CaO, MgO, and BaO; the active component is an oxide of an alkali metal; the filler in the filling section is selected from silicon dioxide and/or aluminum oxide.

In some embodiments of the invention, the length of the packed section is preferably 4.3 to 7.5 times the total length of the first and second catalyst sections. Specifically, when the length of the packed section is preferably 4.3 to 7.5 times the ratio of the total length of the first catalyst section to the second catalyst section, the yield of the carbo-diimides is further improved.

In some embodiments of the invention, the silica may be derived from commercially available quartz sand, and the alumina is preferably alpha-Al₂O₃。

In some embodiments of the invention, the catalyst used is commercially available or prepared by methods known in the art.

According to a preferred embodiment of the present invention, the catalyst without promoter is prepared by: adding a precursor of the active component into deionized water, adding a carrier, stirring for 1-3 hours, drying at 100-120 ℃ for 20-24 hours, and roasting at 700-750 ℃ for 4-6 hours to obtain the catalyst.

According to another preferred embodiment of the present invention, the promoted catalyst is prepared by: adding a precursor of an active component into deionized water, adding a carrier, stirring for 1-3 hours, and then drying at the temperature of 100-120 ℃ for 20-24 hours to obtain a solid A; and then dissolving the precursor of the auxiliary agent in deionized water, adding the solid A, stirring for 1-3 hours, drying at the temperature of 100-750 ℃ for 20-24 hours, and roasting at the temperature of 700-750 ℃ for 4-6 hours to obtain the catalyst.

In some embodiments of the invention, the ratio of the lengths of the first catalyst section and the second catalyst section in the direction of reactant flow is preferably in the range of 1 to 4: 1, more preferably 1-2: 1.

in some embodiments of the invention, the volume ratio of the first catalyst section to the second catalyst section is preferably 1 to 4: 1, more preferably 1-2: 1.

in some embodiments of the invention, the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently further comprises a promoter, preferably at least one of Sr oxide, La oxide, Y oxide and Sm oxide.

In some embodiments of the invention, the adjuvant is preferably present in an amount of 1 to 8g, more preferably 2 to 4g, based on 100g of the carrier.

In some embodiments of the present invention, the active component is preferably at least one of an oxide of Li, an oxide of Na, an oxide of K, and an oxide of Rb.

In some embodiments of the invention, the active ingredient is preferably present in an amount of 1 to 25g, more preferably 3 to 20g, based on 100g of the carrier.

In some embodiments of the present invention, the first catalyst section is further provided with a first oxygen supplement inlet for delivering the first section oxygen to the catalytic reactor, and also as an inlet for the gaseous raw materials (methane and part of oxygen).

In some embodiments of the invention, the packed section is further provided with a second supplemental oxygen inlet for delivering a second section of oxygen to the catalytic reactor in order to control the degree of conversion of the catalytic reaction and to increase the yield and selectivity of the product carbo-hydrocarbons.

In some embodiments of the invention, to further reduce the occurrence of side reactions, the second oxygen supplement inlet is spaced from the cross-section of the upstream end of the second catalyst section by a distance of from 0.5 to 0.9 times the length of the packed section in the reverse direction of the reactant flow.

In a second aspect the present invention provides a process for the oxidative coupling of methane to produce a carbo-carburis, which process comprises:

(1) sequentially filling a catalyst and a filler in a catalytic reactor along the reverse direction of a reactant flow to form a catalyst system comprising a second catalyst section, a filling section and a first catalyst section, wherein the length of the filling section is 4-10 times of the total length of the first catalyst section and the second catalyst section in the reactant flow direction;

the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently comprise a carrier and an active component supported on the carrier, wherein the carrier is at least one of CaO, MgO, and BaO; the active component is an oxide of an alkali metal; the filler in the filling section is selected from silicon dioxide and/or aluminum oxide;

(2) methane and oxygen are introduced into a catalytic reactor to contact with a catalyst to perform a catalytic reaction.

In some embodiments of the invention, the length of the packed section is preferably 4.3 to 7.5 times the total length of the first and second catalyst sections.

In some embodiments of the present invention, the type of the catalytic reactor is not limited as long as the catalytic reaction for oxidative coupling of methane to produce a carbo-diimide can be performed, and specifically, may be a batch tank reactor, a continuous tank reactor, or a semi-continuous tank reactor, and preferably, the catalytic reactor is a fixed bed reactor.

In some embodiments of the invention, the ratio of the lengths of the first catalyst section and the second catalyst section is preferably in the range of 1 to 4: 1, more preferably 1-2: 1.

in some embodiments of the invention, the volume ratio of the first catalyst section to the second catalyst section is preferably 1 to 4: 1, more preferably 1-2: 1.

in some embodiments of the invention, the catalyst in the first catalyst section and the catalyst in the second catalyst section are the same or different and each independently further comprises a promoter, preferably at least one of Sr oxide, La oxide, Y oxide and Sm oxide.

In some embodiments of the invention, the adjuvant is preferably present in an amount of 1 to 8g, more preferably 2 to 4g, based on 100g of the carrier.

In some embodiments of the present invention, the active component is preferably at least one of an oxide of Li, an oxide of Na, an oxide of K, and an oxide of Rb.

In some embodiments of the invention, the active ingredient is preferably present in an amount of 1 to 25g, more preferably 3 to 20g, based on 100g of the carrier.

In some embodiments of the invention, the first catalyst section is further provided with a first oxygen make-up inlet to introduce methane and first section oxygen into the catalytic reactor.

In some embodiments of the invention, the packing section is further provided with a second supplemental oxygen inlet for introducing a second section of oxygen into the catalytic reactor in order to control the degree of conversion of the catalytic reaction and to increase the yield and selectivity of the product carbo-diimides.

In some embodiments of the present invention, to further reduce the occurrence of side reactions, the distance between the second oxygen supplement inlet and the cross-section of the upstream end of the second catalyst section in the reverse direction of the reactant flow is preferably 0.5 to 0.9 times the length of the packed section.

In some embodiments of the present invention, the temperature of the oxygen inlet point of the second-stage oxygen is preferably 680-750 ℃, more preferably 700-750 ℃;

in some embodiments of the invention, the volume ratio of the first stage oxygen to the second stage oxygen is preferably 1 to 10: 1, more preferably 4 to 10: 1. the inventor of the invention finds that the oxygen distributed to each bed layer after the oxygen is fed in the subsection is smaller than that fed in the single section, thereby controlling the temperature rise of the catalyst bed layer, and the methane conversion rate and the selectivity of the reaction can be adjusted, further inhibiting the occurrence of side reaction, and further improving the yield and the selectivity of the product of the carbo-hydrocarbon.

In some embodiments of the invention, the volume ratio of methane to total oxygen input to the catalytic reactor is preferably from 2 to 6: 1, more preferably 2.2 to 4: 1.

in some embodiments of the invention, the conditions of the catalytic reaction include: the reaction temperature is preferably 680-800 deg.C, more preferably 700-750 deg.C. The catalytic reaction pressure is 0-0.02 MPa. The catalytic reaction time is 0.5-8 h. The hourly space velocity of the reaction gas based on methane and oxygen is 5000-25000 mL/(g.h). Specifically, the reaction temperature refers to a temperature 1cm above the first stage catalyst bed.

In the present invention, the unit "mL/(g.h)" is the amount (mL) of the total gas of methane and oxygen used at a time of 1 hour, relative to 1g of the catalyst by mass.

In the present invention, the pressure means gauge pressure.

In the present invention, the carbo-hydrocarbon may be ethane and/or ethylene.

The present invention will be described in detail below by way of examples. In the examples and comparative examples, the reagents used were all commercially available analytical reagents. SiO 2₂Is derived from quartz sand, and the quartz sand is purchased from Qingdao ocean chemical industry Co. Alumina is available from nodulizer fillers, ltd. The method for measuring the element composition of the catalyst is an X-ray fluorescence method, and the specific detection refers to GB/T30905-2014.

Preparation example 1

The preparation method of the catalyst without the auxiliary agent comprises the following steps: adding a precursor of the active component into deionized water with the temperature of 50 ℃ and the weight of 25g, adding a carrier, stirring for 2 hours, drying for 24 hours at the temperature of 120 ℃, and then roasting for 6 hours at the temperature of 750 ℃ to obtain the catalyst used in the embodiment.

Preparation example 2

The preparation method of the catalyst with the auxiliary agent comprises the following steps: adding a precursor of the active component into deionized water at 50 ℃ and 25g, adding a carrier, stirring for 2 hours, and drying at 120 ℃ for 24 hours to obtain a solid A; then dissolving the precursor of the auxiliary agent in deionized water with the temperature of 50 ℃ and the weight of 25g, adding the solid A, stirring for 2 hours, drying for 24 hours at the temperature of 120 ℃, and then roasting for 6 hours at the temperature of 750 ℃ to obtain the catalyst used in the embodiment.

In the preparation examples, the precursor of the active component and the precursor of the auxiliary agent both refer to nitrate, and the usage amount of each component is such that the content of the active component and the auxiliary agent in the catalyst is shown in table 1:

TABLE 1

Note: the content of each component in the catalyst is based on 100g of carrier;

"/" indicates no promoter is present in the catalyst.

Example 1

The catalyst corresponding to example 1 described in table 1 was loaded in a quartz reactor having an inner diameter of 8mm and a length of 530mm, the catalyst was divided into an upper section and a lower section, the loading amounts of both the two sections were 0.4g, the length of the first catalyst section was 4mm, the length of the second catalyst section was 4mm, the space between the two catalyst sections was filled with quartz sand, and the length of the filling section was 3.5 cm. The mixed gas of methane and the first-stage oxygen is continuously introduced into the first-stage catalyst bed layer, and the reaction temperature is 750 ℃. The distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 3cm, and the temperature of the second section oxygen inlet point is 700 ℃. The reaction pressure is the pressure generated by the raw material, namely 0.011MPa, the volume ratio of methane to the total oxygen input into the catalytic reactor is 2.2, the volume ratio of the first-stage oxygen to the second-stage oxygen is 10, the hourly space velocity of the reaction gas calculated by methane and oxygen is 12000 mL/(g.h), and the reaction product is collected after 1 hour of reaction.

Example 2

The catalyst corresponding to example 2 described in table 1 was loaded in a quartz reactor having an inner diameter of 8mm and a length of 530mm, the catalyst was divided into upper and lower sections, the loading of the first section was 0.6g, the loading of the second section was 0.2g, the length of the first catalyst section was 6mm, the length of the second section was 2mm, the space between the two sections of catalyst was filled with alumina, and the length of the packed section was 6 cm. The mixed gas of methane and the first-stage oxygen is continuously introduced into the first-stage catalyst bed layer, and the reaction temperature is 700 ℃. The distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 4cm, and the temperature of the second section oxygen inlet point is 750 ℃. The reaction pressure is the pressure generated by the raw material, namely 0.008MPa, the volume ratio of methane to the total oxygen input into the catalytic reactor is 3, the volume ratio of the first-stage oxygen to the second-stage oxygen is 4, the hourly space velocity of the reaction gas calculated by methane and oxygen is 5000 mL/(g.h), and the reaction product is collected after 1 hour of reaction.

Example 3

The catalyst corresponding to example 3 described in table 1 was loaded in a quartz reactor having an inner diameter of 8mm and a length of 530mm, the catalyst was divided into an upper section and a lower section, the loading of the first section was 0.55g, the loading of the second section was 0.25g, the length of the first catalyst section was 5.5mm, the length of the second catalyst section was 2.5mm, the space between the two sections of catalyst was filled with alumina, and the length of the filling section was 4 cm. The mixed gas of methane and the first-stage oxygen is continuously introduced into the first-stage catalyst bed layer, and the reaction temperature is 730 ℃. The distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 2cm, and the temperature of the second section oxygen inlet point is 720 ℃. The reaction pressure is the pressure generated by the raw material, namely 0.018MPa, the volume ratio of methane to the total oxygen input into the catalytic reactor is 4, the volume ratio of the first-stage oxygen to the second-stage oxygen is 6, the hourly space velocity of the reaction gas calculated by methane and oxygen is 25000 mL/(g.h), and the reaction product is collected after 1 hour of reaction.

Example 4

The catalyst corresponding to example 4 described in table 1 was loaded in a quartz reactor having an inner diameter of 8mm and a length of 530mm, the catalyst was divided into an upper section and a lower section, the loading of the first section was 0.64g, the loading of the second section was 0.16g, the length of the first catalyst section was 6.4mm, the length of the second catalyst section was 1.6mm, the space between the two sections of catalyst was filled with quartz sand, and the length of the filling section was 5 cm. The mixed gas of methane and the first-stage oxygen is continuously introduced into the first-stage catalyst bed layer, and the reaction temperature is 680 ℃. The distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 4cm, and the temperature of the second section oxygen inlet point is 680 ℃. The reaction pressure is the pressure generated by the raw material, namely 0.015MPa, the volume ratio of methane to the total oxygen input into the catalytic reactor is 6, the volume ratio of the first-stage oxygen to the second-stage oxygen is 4, the hourly space velocity of the reaction gas calculated by methane and oxygen is 20000 mL/(g.h), and the reaction product is collected after 1 hour of reaction.

Example 5

The catalyst corresponding to example 5 described in table 1 was loaded in a quartz reactor having an inner diameter of 8mm and a length of 530mm, the catalyst was divided into an upper section and a lower section, the loading amounts of both the two sections were 0.4g, the length of the first catalyst section was 4mm, the length of the second catalyst section was 4mm, the space between the two catalyst sections was filled with quartz sand, and the length of the filling section was 6 cm. The mixed gas of methane and the first-stage oxygen is continuously introduced into the first-stage catalyst bed layer, and the reaction temperature is 800 ℃. The distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 5cm, and the temperature of the second section oxygen inlet point is 750 ℃. The reaction pressure is the pressure generated by the raw material, namely 0.012MPa, the volume ratio of methane to the total oxygen input into the catalytic reactor is 2, the volume ratio of the first-stage oxygen to the second-stage oxygen is 3, the hourly space velocity of the reaction gas calculated by methane and oxygen is 10000 mL/(g.h), and the reaction product is collected after 1 hour of reaction.

Example 6

The catalyst corresponding to example 6 described in table 1 was loaded in a quartz reactor having an inner diameter of 8mm and a length of 530mm, the catalyst was divided into an upper section and a lower section, the loading amounts of both the two sections were 0.4g, the length of the first catalyst section was 4mm, the length of the second catalyst section was 4mm, the space between the two catalyst sections was filled with quartz sand, and the length of the filling section was 8 cm. The mixed gas of methane and the first-stage oxygen is continuously introduced into the first-stage catalyst bed layer, and the reaction temperature is 700 ℃. The distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 4cm, and the temperature of the second section oxygen inlet point is 720 ℃. The reaction pressure is the pressure generated by the raw material, namely 0.013MPa, the volume ratio of methane to the total oxygen input into the catalytic reactor is 6, the volume ratio of the first-stage oxygen to the second-stage oxygen is 1, the hourly space velocity of the reaction gas calculated by methane and oxygen is 20000 mL/(g.h), and the reaction product is collected after 1 hour of reaction.

Comparative example 1

The catalyst corresponding to comparative example 1 described in Table 1 was packed in a quartz reactor having an inner diameter of 8mm and a length of 530mm, and the catalyst was packed in a single stage in an amount of 0.8g and a length of 8mm, and the upper and lower sides of the catalyst were packed with quartz sand. The mixed gas of methane and oxygen is continuously introduced into the catalyst bed layer, and the reaction temperature is 680 ℃. The reaction pressure is the pressure generated by the raw material, namely 0.015MPa, the volume ratio of methane to the total oxygen input into the catalytic reactor is 6, the hourly space velocity of reaction gas calculated by methane and oxygen is 20000 mL/(g.h), and the reaction product is collected after 1 hour of reaction.

Comparative example 2

The reaction for producing a hydrocarbon by oxidative coupling of methane was carried out in the same manner as in example 2 except that the length of the packed section was 12 cm. The distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 1 cm.

Comparative example 3

The reaction for producing a hydrocarbon by oxidative coupling of methane was carried out in the same manner as in example 2 except that the length of the packed section was 2 cm. The distance between the second oxygen supplement inlet and the cross section of the upstream end of the second catalyst section is 0.2 cm.

Comparative example 4

The reaction for producing a hydrocarbon by oxidative coupling of methane was carried out in the same manner as in example 4, except that the catalyst was replaced with another catalyst, as shown in Table 1.

Comparative example 5

The reaction for producing a hydrocarbon by oxidative coupling of methane was carried out in the same manner as in comparative example 1, except that the catalyst used in comparative example 4 was used.

Test example 1

The reaction product components obtained in the examples and comparative examples were measured on a gas chromatograph available from Agilent under the model number 7890A. The product is measured by a double detection channel triple valve four-column system, wherein the FID detector is connected with an alumina column and is used for analyzing CH₄、C₂H₆、C₂H₄、C₃H₈、C₃H₆、C₄H₁₀、C₄H₈、C_nH_mEqual-component TCD detector mainly used for detecting CO and CO₂、N₂、O₂、CH₄。

The methane conversion and the like are calculated as follows:

methane conversion ═ amount of methane consumed by the reaction/initial amount of methane × 100%

Ethylene selectivity is the amount of methane consumed by ethylene produced/total consumption of methane × 100%

Ethane selectivity is the amount of methane consumed by ethane produced/total consumption of methane × 100%

Carbo-carb selectivity ═ ethane selectivity + ethylene selectivity

CO_x(CO+CO₂) Selectivity to CO and CO formed₂The amount of co-consumed methane/total consumption of methane X100%

Yield of carbo-carb ═ methane conversion x (ethane selectivity + ethylene selectivity)

The results obtained are shown in Table 2.

TABLE 2

As can be seen from Table 2, when the length of the packed section is 4 to 10 times the total length of the first catalyst section and the second catalyst section, the methane conversion ratio is higher, the selectivity to the carbo-diimides is higher, the yield of the carbo-diimides is higher, and CO is higher in examples 1 to 6 than in comparative examples 1 to 5_xThe selectivity is relatively low, which indicates that the deep oxidation of methane is inhibited and the occurrence of side reactions is reduced when the catalyst system is used for preparing the carbon dioxide hydrocarbons by methane oxidative coupling, and the side indicates that the technical scheme can effectively control the heat generated by the methane oxidative coupling reaction and reduce the occurrence of temperature runaway phenomenon. Compared with comparative examples 4-5 (the carriers are SiC), the methane conversion rate, the selectivity of the carbon dioxide and the yield of the carbon dioxide of examples 1-6 are high, and the effect of the mode of adopting multi-stage filling in comparative example 4 is similar to that of the mode of adopting single-stage filling in comparative example 5, which shows that the better catalytic effect can be obtained only by adopting the multi-stage filling mode for a specific catalyst.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.