CN101830769B - Method for converting methanol into propylene - Google Patents

Abstract

The invention discloses a method for converting methanol into propylene, which comprises the following steps of: introducing methanol into a methanol reaction zone to perform reaction so as to obtain a mixture of the methanol, dimethyl ether and water; dividing the mixture into a plurality of reactant streams; feeding the first reactant stream to a first reaction zone to perform reaction to obtain a product stream, mixing the product stream and any one of the other reactant streams, feeding the mixture to the first reaction zone to perform reaction until the product stream is mixed with the last reactant stream and feeding the mixture to the first reaction zone to perform reaction so as to obtain a primary reaction product stream; separating the primary reaction product stream to obtain the propylene, propane, C1 to C2 hydrocarbon, C4 hydrocarbon, C5 to C6 hydrocarbon and hydrocarbons with more than seven carbon atoms; circulating the C1 to C2 hydrocarbon and the C4 hydrocarbon to the first reaction zone to perform reaction continuously; feeding the C5 to C6 hydrocarbon and part of the hydrocarbons with more than seven carbon atoms to the second reaction zone to perform reaction so as to obtain a secondary reaction product stream; and separating the secondary reaction product stream to obtain the propylene. The method is suitable for the reactions with high heat discharge and temperature sensitivity such as the reaction for preparing the propylene from the methanol and has the advantages of high target selectivity, continuous and stable reaction and high efficiency.

Description

A method of converting methanol into propylene

technical field

The invention relates to a method for preparing propylene, in particular to a method for converting methanol into propylene.

Background technique

Propylene is a basic chemical raw material necessary for the modern chemical industry. With the continuous development of the industrial economy, the demand will continue to grow in the future. The traditional industrial production of propylene basically uses petroleum-based substances as raw materials, such as steam cracking of petroleum, etc. As a non-renewable resource, oil is facing a crisis of being exhausted in the long run after years of excessive exploitation and consumption. In the short term, the price fluctuates violently due to factors such as geography, economy, and politics. A method that can replace petroleum as a raw material to produce propylene has been sought.

Methanol to propylene technology is a non-petroleum resource propylene production process with great application prospects. At present, the relatively mature ones in the world mainly include UOP's fluidized bed methanol-to-olefin (MTO) technology and Germany's Lurgi company's fixed-bed methanol-to-propylene (MTP) technology. The former mainly produces ethylene and propylene, while the latter mainly produces propylene.

The fluidized bed technology mainly uses SAPO-34 catalyst, which has a high selectivity to low-carbon olefins, but the single selectivity of propylene is not high, and the secondary reaction of products is required to improve the selectivity of propylene, so the process investment is relatively larger. In addition to UOP, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Tsinghua University are engaged in the development of fluidized bed technology in China.

The patentee of fixed bed technology is mainly German Lurgi Company, which has a high selectivity to propylene. The European patent EP0448000B1 and the Chinese patent CN1431982A disclose the process and the catalyst used for the fixed-bed methanol production of German Lurgi company. According to the disclosed content of the patent and the information disclosed by Lurgi company, the process method has a higher yield of propylene At the same time, a small amount of ethylene, LPG (liquefied petroleum gas) and gasoline are produced by-products. Since the catalyst in the fixed bed needs to be regenerated in situ, Lurgi Company set up multiple fixed bed reactors for switching in its commercial demonstration plant to solve the above problems, but at the same time, it caused the problems of high requirements for system equipment and complicated operation.

ZSM-5 is a molecular sieve catalyst with mesoporous nature and moderate carbon deposition rate. Moving bed technology is a continuous reaction regeneration technology, especially suitable for catalysts with medium carbon deposition rate. It can be continuously reacted and regenerated like a circulating fluidized bed, and at the same time does not require high wear resistance requirements.

The Chinese patent application with the publication number CN1803738A and the Chinese patent application with the publication number CN101023048A disclose a moving bed methanol-to-propylene technology, which improves the selectivity of propylene by controlling a certain catalyst circulation rate and a specific treatment method. However, the heat removal capacity of the moving bed reactor itself is weak, and the reaction of methanol to propylene is a strong exothermic process. If the heat in the reactor is not removed in time, not only will the reaction temperature increase rapidly, but the selectivity of propylene will decrease. In severe cases, it will lead to The reactor overheated, causing a safety accident. However, the above two patent applications do not mention how to solve the problem of heat removal in the moving bed.

Therefore, the design and development of a moving bed reactor with strong heat removal capacity and a method for converting methanol into propylene is of great significance for improving the selectivity of propylene and the stability of the reaction.

Contents of the invention

The invention provides a method for converting methanol into propylene, which mainly solves the problems of heat removal, discontinuous production and low selectivity of propylene in a strong exothermic reaction in a methanol-to-propylene moving bed reactor.

A method for converting methanol into propylene, comprising the steps of:

(1) Methanol is passed into the methanol reaction zone to contact with the catalyst for reaction, and the reaction obtains a mixture of methanol, dimethyl ether and water;

(2) The above-mentioned mixture of methanol, dimethyl ether and water is divided into several reactant streams, the first reactant stream is sent to the first reaction zone, and reacts with the catalyst to obtain the product stream, and the product stream is combined with any other reactant stream After being mixed, it is sent to the first reaction zone, and is contacted and reacted with the catalyst until the product stream is mixed with the last reactant stream, and then sent to the first reaction zone, where it is contacted and reacted with the catalyst to obtain a primary reaction product stream rich in propylene;

(3) The above-mentioned primary reaction product stream is sent to the separation zone, and after dehydration and deoxidation, propylene, propane, C ₁ -C ₂ hydrocarbons, C ₄ hydrocarbons, C ₅ -C ₆ hydrocarbons, and C ₇ Heavy components of the above hydrocarbons;

(4) C ₁ -C ₂ hydrocarbons and C ₄ hydrocarbons are recycled to the first reaction zone to continue the reaction;

(5) Sending C ₅ -C ₆ hydrocarbons and some heavy components of C ₇ or more hydrocarbons into the second reaction zone, contacting and reacting with the catalyst to obtain a secondary reaction product stream containing propylene;

The mass of the heavy components of hydrocarbons above _C7 is less than 30% of the total mass of heavy components of hydrocarbons above _C7 , and the remaining heavy components of hydrocarbons above _C7 are as by-products;

(6) sending the above-mentioned secondary reaction product flow into the separation zone to obtain propylene, propane, C ₁ -C ₂ hydrocarbons, C ₄ hydrocarbons, C ₅ -C ₆ hydrocarbons and heavy components of C ₇ or more hydrocarbons;

(7) The catalyst is discharged from the second reaction zone after carbon deposition, enters the regeneration zone for regeneration, and then circulates to the methanol reaction zone. When the catalyst is deactivated by carbon deposits to a certain extent, methanol will penetrate the catalyst bed layer. At this time, the catalyst needs to be sent to the regeneration zone for regeneration to maintain optimal reactivity and selectivity.

The methanol reaction zone, the first reaction zone and the second reaction zone are preferably made up of several vertical moving bed reactors connected in series, so that the bottom of each moving bed reactor is connected to the top of the next moving bed reactor ( For example, it can be connected by a pipeline). This arrangement can ensure that the catalyst moves from top to bottom by its own gravity, and passes through each moving bed reactor sequentially from top to bottom, so that the raw material methanol and the catalyst form a cross-flow; at the same time, it can also reduce energy consumption.

The methanol reaction zone is at least one moving bed reactor.

The first reaction zone is at least two vertical moving bed reactors connected in series, and the number of reactant streams is the same as the number of moving bed reactors in the first reaction zone.

The second reaction zone is at least one moving bed reactor.

The invention can adjust the number of moving bed reactors in each reaction zone according to the capacity.

The total number of moving bed reactors in the methanol reaction zone, the first reaction zone and the second reaction zone is preferably 4-8 to save cost.

The methanol reaction zone, the first reaction zone and the second reaction zone are all equipped with heat exchange devices. The heat exchange device is located in the moving bed reactor and/or between the moving bed reactors. A heat exchange device is installed in the moving bed reactor to remove the heat of reaction generated during the reaction. A heat exchange device is arranged between each moving bed reactor to facilitate better control of the reaction temperature of each step of reaction. In the specific setting, the heat exchange device can be placed between the wall of the moving bed reactor and the catalyst bed and/or between the catalyst bed and the catalyst bed.

A quenching device is provided in the first reaction zone, and the quenching liquid flowing out from the quenching device is mixed with any reactant flow.

When the heat release is too large, the heat exchange device in the moving bed reactor and between the moving bed reactors still cannot remove the heat of reaction. At this time, adding a quenching device between the moving bed reactors can effectively remove the excess reaction. The heat is used to quickly reduce the temperature of the product stream to the inlet temperature of the next moving bed reactor. The chilling liquid in the chilling device can be methanol or water or a mixture of methanol and water.

The quenching liquid is selected from methanol or water or a mixture of the two, and when methanol or a mixture of methanol and water is used, the throughput of raw materials can be increased at the same time.

The catalyst may be a catalyst commonly used in the preparation of propylene from methanol, preferably a ZSM-5 molecular sieve catalyst.

The reaction of methanol to propylene first dehydrates the raw material methanol on the catalyst to form a mixture of dimethyl ether, methanol and water, and then methanol and dimethyl ether continue to react on the catalyst to form hydrocarbon compounds containing propylene. The two-step reaction is an exothermic reaction , in order to reduce the heat load of a single moving bed reactor, the present invention puts the above-mentioned two-step reaction in different reaction zones, that is, respectively in the methanol reaction zone and the first reaction zone.

The methanol dehydration reaction is generally carried out at 250°C-300°C, while the further generation of propylene-containing hydrocarbons requires a temperature of 450°C-500°C. Therefore, the inlet temperature of the methanol reaction zone is 250°C-300°C, and the inlet temperature of each moving bed reactor in the methanol reaction zone remains the same; the inlet temperature of the first reaction zone is 450°C- 500°C, and the inlet temperature of each moving bed reactor in the first reaction zone remains the same.

The inlet temperature of the second reaction zone is preferably 15°C-30°C higher than the inlet temperature of the first reaction zone, and the inlet temperature of each moving bed reactor in the second reaction remains the same.

Since the further conversion of methanol, dimethyl ether and water mixture into propylene-containing hydrocarbons is a strong exothermic reaction, it is preferable to divide the reaction into multiple processes in the first reaction zone, which can disperse the heat of reaction and pass through the moving bed at the same time. Adding a heat exchange device and a chilling device to the reactor can control the temperature rise in a lower range and improve the selectivity of propylene. In principle, the more the number of moving bed reactors, the better the temperature control, but it will lead to increased equipment investment and more complicated operation, so the first reaction zone is generally preferably 3-5 moving bed reactors.

Methanol and dimethyl ether are reacted once to obtain a propylene-rich product stream. The by-products include propane, C ₁ -C ₂ hydrocarbons, C ₄ hydrocarbons, C ₅ -C ₆ hydrocarbons, and heavy components of hydrocarbons above C ₇ , with economic value Low by-products (such as C ₅ -C ₆ hydrocarbons and heavy components of C ₇ and above hydrocarbons) can be further converted to propylene through secondary reactions. Due to the partial carbon deposition of the catalyst in the second reaction zone, the activity is reduced. In order to compensate for the activity and meet the requirements of the hydrocarbon cracking reaction, the reaction temperature of the second reaction zone is slightly higher than that of the first reaction zone. Since the reaction described in the present invention belongs to the temperature-sensitive reaction, the reaction temperature has a greater influence on the selectivity of propylene, so each reactor in the first reaction zone maintains the same temperature, and each reactor in the second reaction zone also maintains the same temperature , to obtain the highest propylene selectivity.

The present invention has the following advantages:

(1) The present invention divides reaction into several and carries out, and multi-strand raw material is sampled respectively, reduces the exothermic heat of single reactor;

(2) The present invention quickly removes the heat of reaction by adding a heat exchange device in the reactor and/or the device;

(3) In the present invention, a quenching device is added in the first reaction zone with the largest heat release, so as to enhance the heat removal capacity and simultaneously increase the raw material processing capacity.

(4) The present invention adopts the second reaction zone to refine part of the products to improve the selectivity of propylene.

(5) The present invention adopts the overlapping arrangement of multiple reaction zones, and the catalyst is continuously flowed and regenerated to realize long-term continuous reaction.

(6) The method of the present invention can better solve the heat removal problem of the heat of reaction in the existing moving bed reactor, so that the reaction of methanol and dimethyl ether into propylene is carried out in a stable temperature range, with high propylene selectivity and Response stability. At the same time, the continuity of the catalyst and product flow is realized through the upper and lower continuous reactor arrangement and continuous reaction regeneration, so that the production process can be carried out continuously and the efficiency is high.

Description of drawings

Fig. 1 is the technological process schematic diagram of the inventive method;

Fig. 2 is the technological process schematic diagram of a kind of reactor that the inventive method adopts;

Feedstock and product streams are represented by dotted lines, and catalyst streams are represented by solid lines. To simplify the description, components such as heaters, partial heat exchangers, separation zones, regeneration zones, pipelines, and valves are omitted in the figure.

Detailed ways

As shown in Figure 1 and Figure 2, a moving bed reactor is used in the methanol reaction zone, three moving bed reactors are used in the first reaction zone, and a moving bed reactor is used in the second reaction zone as an example for specific description.

The raw material methanol is heat-exchanged to the inlet temperature of the methanol reaction zone through the heat exchanger (select a constant value between 250°C and 300°C according to the actual situation), and then enters the methanol moving bed reactor D1, and enters the annular catalyst bed through the central pipe 1 2. After contacting with the catalyst, a mixture of methanol, dimethyl ether and water with a higher temperature than the inlet temperature of the methanol reaction zone is generated. The mixture flows out from the outlet 4 of the methanol moving bed reactor D1, and at the same time, the wall of the methanol moving bed reactor D1 The set heat exchange tube 3 performs a heat exchange on the mixture, and exchanges the heat of the mixture (ie, the reaction product in the methanol moving bed reactor D1) to 300°C-400°C.

The reaction product from the methanol moving bed reactor D1 is first mixed with water vapor from public works (not shown in the figure), and then heated to the inlet temperature of the first reaction zone (according to actual conditions) with a heating furnace (not shown in the figure). A constant value in 450 ℃-500 ℃ is selected according to the situation), and according to a certain ratio (deciding according to the actual situation, the present embodiment selects a weight ratio of 1: 1.4: 1.8) and is divided into reactant stream a, reactant stream b and reactant stream c three reactant streams (can be divided into several strands according to actual conditions), respectively sent to three moving bed reactors (moving bed reactor D2, moving bed reactor D3, moving bed reactor D4) in the first reaction zone The number of reactors is the same as the number of reactant streams).

The reactant stream a passes through the moving bed reactor D2, and after being catalyzed by the annular catalyst bed layer, it flows out from the outlet 5 of the moving bed reactor D2, and at the same time, a large amount of heat released is partially removed through the heat exchange tubes on the wall of the moving bed reactor D2 The reaction product stream coming out from the outlet 5 of the moving bed reactor D2 and the mixture stream 6 after the reactant flow b from the methanol moving bed reactor D1 and the cold shock liquid 12 are mixed, further cooled to the first in the heat exchanger R1 The inlet temperature of the reaction zone then enters the moving bed reactor D3, and after the catalytic reaction of the annular catalyst bed, it flows out from the outlet 7 of the reactor D3, and at the same time, a large amount of heat released is partially removed through the heat exchange tubes on the wall of the reactor D3.

The mixture flow 8 after mixing the reactant flow from the outlet 7 of the moving bed reactor D3 with the reactant flow c from the methanol moving bed reactor D1 and the quench liquid 13 is further cooled to the inlet of the first reaction zone in the heat exchanger R2 Then it enters the moving bed reactor D4, and after continuing the catalytic reaction through the annular catalyst bed, it flows out from the outlet of the moving bed reactor D4, and a large amount of heat released at the same time is removed through the heat exchange tubes on the wall of the moving bed reactor D4 .

Wherein, the inlet temperatures of the moving bed reactor D2, the moving bed reactor D3 and the moving bed reactor D4 are kept the same.

Finally, the propylene-rich reaction product stream 14 from the moving bed reactor D4 is sent to a separation zone (not shown in the figure) for separation to obtain propylene and propylene-free by-products, which mainly include C ₁ - C ₂ hydrocarbons, propane, C ₄ hydrocarbons, C ₅ -C ₆ hydrocarbons, and the heavy components of C ₇ or more hydrocarbons (that is, C ₇ + hydrocarbons, referring to hydrocarbon compounds with carbon atoms ≥ 7). After the separated C ₁ -C ₂ hydrocarbons and C ₄ hydrocarbons are heat-exchanged by a heat exchanger (not shown in the figure), they are further heated to the inlet temperature of the first reaction zone by a heating furnace (not shown in the figure), It is then mixed with product stream 4 from the methanol reaction zone and enters the first reaction zone. The separated by-products _C5 - _C6 hydrocarbons and the heavy components of _C7 and above hydrocarbons accounting for less than 30% of the total mass of heavy hydrocarbons above _C7 are heat exchanged by a heat exchanger (not shown in the figure) , further heated to the inlet temperature of the second reaction zone (15°C-30°C higher than the temperature of the first reaction zone) with a heating furnace (not shown in the figure), and then sent to the moving bed reactor D5 in the second reaction zone, through After the secondary reaction is catalyzed by the annular catalyst bed, the product stream 16 generated by the reaction flows out from the outlet of the moving bed reactor D5, and a large amount of heat released is partially removed through the heat exchange tubes on the wall of the moving bed reactor D5.

The product stream 16 produced by the reaction in the moving bed reactor D5 is sent to the separation zone for separation to obtain propylene.

The regenerated catalyst from the regeneration zone and the added fresh catalyst are first sent to the methanol moving bed reactor D1 in the methanol reaction zone through the feeding equipment (not shown in the figure), and slowly move down by gravity, from the methanol moving bed reactor The catalyst from D1 passes through the catalyst tube 9, the catalyst tube 10, and the catalyst tube 11 respectively by gravity, and then passes through the moving bed reactor D2, the moving bed reactor D3, and the moving bed reactor D4 in the first reaction zone, and then comes from the first reaction zone. The catalyst in the moving bed reactor D4 of the zone is also fed into the moving bed reactor D5 of the second reaction zone through the catalyst tube by gravity. The catalyst coming out of the moving bed reactor D5 has been deactivated by carbon deposition, and is sent to the catalyst collection hopper 17, and then the carbon deposition catalyst 18 is sent to the regeneration zone for regeneration.

The regenerator in the regeneration zone adopts a continuous moving bed reactor or a fluidized bed reactor, so as to realize the continuous reaction regeneration of the catalyst.

Example 1

The catalyst used in this example is a ZSM-5 molecular sieve spherical catalyst with a particle size of 1.6mm-2mm, and the raw material used is methanol.

The methanol reaction zone adopts a moving bed reactor with an inlet temperature of 250°C and normal pressure operation.

The first reaction zone adopts three moving bed reactors, each with an inlet temperature of 500°C, operated under normal pressure, and the mixture of methanol, dimethyl ether and water is divided into three reactant streams according to the weight ratio of 1:1.4:1.8; the quenching liquid uses methanol .

The second reaction zone adopts a moving bed reactor with an inlet temperature of 525°C and normal pressure operation.

The carbon deposition catalyst carbon deposition amount removed from the bottom of the catalyst bed is less than 2%, and it is sent to the regenerator for regeneration. The catalyst carbon deposition amount after regeneration is less than 0.5% (carbon deposition amount=the carbon deposition quality deposited on the catalyst per unit weight) ).

Other operations are the same as the above-mentioned embodiment.

Table 1 lists the material balance under the above conditions. The material balance is obtained based on the experimental data and scaled up to the annual processing capacity of one million tons of methanol through computer simulation. It can be known from Table 1 that the feed rate of methanol is 208333 kg/h, the amount of propylene produced is 66573 kg/h, and the conversion rate of methanol is greater than 99%.

Table 1 Material balance

material Material flow Methanol 208333kg/h Propylene 66573kg/h

LPG 5887kg/h gasoline 16725kg/h Water (including trace oxygenates) 117485kg/h Fuel Gas# 1581kg/h Coke, etc.* 82kg/h

In Table 1, # indicates that a small amount of ethylene is included, and * indicates that it includes the loss in material circulation; where LPG is C3-C4 hydrocarbons, mainly alkanes, including a small amount of olefins; gasoline is mainly heavy components above C7, and water is methanol dehydrated The products include unreacted traces of methanol and the generated dimethyl ether, aldehydes and other traces of oxygen-containing compounds. The fuel gas is mainly a small amount of C1-C2 hydrocarbon components. Coke is the carbon deposition on the catalyst, the same below.

Each product was converted into the dry basis percentage content after water removal, and the product distribution relative to the raw material methanol was listed, as shown in Table 2.

Table 2 product distribution

product Percentage of dry basis Propylene 73.28% LPG 6.48% gasoline 18.41% fuel gas 1.74% Coke 0.09%

Example 2

The catalyst used in this example is a ZSM-5 molecular sieve spherical catalyst with a particle size of 1.6mm-2mm, and the raw material used is methanol.

Two moving bed reactors are used in the methanol reaction zone, each with an inlet temperature of 280°C and normal pressure operation.

The first reaction zone adopts four moving bed reactors, each inlet temperature is 450°C, operated under normal pressure, the mixture of methanol, dimethyl ether and water is divided into four reactant streams according to the weight ratio of 1: 1.4: 1.8: 1.2; A mixture of methanol and water was used.

The second reaction zone adopts a moving bed reactor with an inlet temperature of 465°C and normal pressure operation.

The carbon deposition catalyst carbon deposition amount removed from the bottom of the catalyst bed is less than 2%, and it is sent to the regenerator for regeneration. The catalyst carbon deposition amount after regeneration is less than 0.5% (carbon deposition amount=the carbon deposition quality deposited on the catalyst per unit weight) ).

Other operations are the same as in Example 1.

Table 3 lists the material balance under the above conditions. The material balance is obtained based on the experimental data and scaled up to the annual processing capacity of one million tons of methanol through computer simulation. It can be known from Table 3 that the feed amount of methanol is 208333 kg/h, the amount of propylene produced is 66711 kg/h, and the conversion rate of methanol is greater than 99%.

Table 3 material balance

material Material flow rate Methanol 208333kg/h Propylene 66711kg/h LPG 6620kg/h gasoline 16205kg/h Water (including trace oxygenates) 117396kg/h Fuel Gas# 1319kg/h Coke, etc.* 82kg/h

In Table 3, # indicates that a small amount of ethylene is included, and * indicates that losses in material circulation are included.

Each product was converted into the dry basis percentage content after water removal, and the product distribution relative to the raw material methanol was listed, as shown in Table 4.

Table 4 product distribution

product Percentage of dry basis Propylene 73.36% LPG 7.28% gasoline 17.82% fuel gas 1.45% Coke 0.09%

Example 3

The catalyst used in this example is a ZSM-5 molecular sieve spherical catalyst with a particle size of 2mm-3mm, and the raw material used is methanol.

The methanol reaction zone adopts a moving bed reactor, each inlet temperature is 300°C, and it operates under normal pressure.

The first reaction zone adopts three moving bed reactors, each inlet temperature is 450°C, and is operated under normal pressure. The mixture of methanol, dimethyl ether and water is divided into three reactant streams according to the weight ratio of 1:1.4:1.8; the quenching liquid uses methanol Mixture with water.

The second reaction zone adopts a moving bed reactor with an inlet temperature of 480°C and normal pressure operation.

The carbon deposition catalyst carbon deposition amount removed from the bottom of the catalyst bed is less than 2%, and it is sent to the regenerator for regeneration. The catalyst carbon deposition amount after regeneration is less than 0.5% (carbon deposition amount=the carbon deposition quality deposited on the catalyst per unit weight) ).

Other operations are the same as in Example 1.

Table 5 lists the material balance under the above conditions. The material balance is obtained based on the experimental data and scaled up to the annual processing capacity of one million tons of methanol through computer simulation. It can be known from Table 5 that the feed amount of methanol is 208333 kg/h, the amount of propylene produced is 67329 kg/h, and the conversion rate of methanol is greater than 99%.

Table 5 Material Balance

material Material flow rate Methanol 208333kg/hr Propylene 67329kg/hr LPG 7697kg/hr gasoline 14195kg/hr Water (including trace oxygenates) 117459kg/hr Fuel Gas# 1454kg/hr Coke, etc.* 200kg/hr

In Table 5, # indicates that a small amount of ethylene is included, and * indicates that losses in material circulation are included.

Each product was converted into the dry basis percentage after water removal, and the product distribution relative to the raw material methanol was listed, as shown in Table 6.

Table 6 product distribution

product Percentage of dry basis Propylene 74.09% LPG 8.47% gasoline 15.62% fuel gas 1.60% Coke 0.22%

It can be seen from the above three examples that according to the method and reactor technology disclosed in the present invention, better temperature control can be achieved, so that the selectivity of propylene can be maintained at a relatively high level. In addition, operating within the scope disclosed in the present invention, the range of selectivity of the product is small.

Claims (5)

1. one kind is the method for propylene with methanol conversion, may further comprise the steps:

(1) methyl alcohol is fed methanol reaction zone and catalyzer contact reacts, reaction obtains the mixture of methyl alcohol, dme and water;

(2) mixture with above-mentioned methyl alcohol, dme and water is divided into some bursts of reactant flow, and first burst of reactant flow sent into first reaction zone, with the catalyzer contact reacts; Obtain product stream; Product stream is sent into first reaction zone after one reactant flow is mixed arbitrarily with other, with the catalyzer contact reacts, flows and sends into first reaction zone after one reactant flow is mixed at last until product; With the catalyzer contact reacts, obtain being rich in the primary first-order equation product stream of propylene;

(3) above-mentioned primary first-order equation product stream is sent into the disengaging zone, behind dehydration and oxide removal, obtain propylene, propane, C respectively ₁-C ₂Hydrocarbon, C ₄Hydrocarbon, C ₅-C ₆Hydrocarbon and C ₇The heavy constituent of above hydrocarbon;

(4) with C ₁-C ₂Hydrocarbon and C ₄Hydrocarbon be circulated to first reaction zone and continue reaction;

(5) with C ₅-C ₆Hydrocarbon and portion C ₇Second reaction zone is sent in the heavy constituent of above hydrocarbon, with the catalyzer contact reacts, obtains containing the secondary reaction product stream of propylene;

Described portion C ₇The quality of the heavy constituent of above hydrocarbon is C ₇Below 30% of heavy constituent total mass of above hydrocarbon;

(6) above-mentioned secondary reaction product stream is sent into the disengaging zone, obtain propylene, propane, C respectively ₁-C ₂Hydrocarbon, C ₄Hydrocarbon, C ₅-C ₆Hydrocarbon and C ₇The heavy constituent of above hydrocarbon;

(7) discharge from second reaction zone behind the described catalyst carbon deposit, get into and be circulated to methanol reaction zone after regenerating in the breeding blanket;

Described methanol reaction zone, first reaction zone and second reaction zone are made up of the setting moving-burden bed reactor that several are connected in series;

Wherein, described methanol reaction zone is at least one moving-burden bed reactor;

Described first reaction zone is at least two setting moving-burden bed reactors that are connected in series, and the number of share of stock of described reactant flow is identical with the number of the first reaction zone moving-burden bed reactor;

Described second reaction zone is at least one moving-burden bed reactor;

Total number of moving-burden bed reactor is 4-8 in described methanol reaction zone, first reaction zone and second reaction zone.

2. method according to claim 1 is characterized in that: described methanol reaction zone, first reaction zone and second reaction zone are equipped with heat-exchanger rig;

Described heat-exchanger rig is in moving-burden bed reactor and/or between each moving-burden bed reactor;

Be provided with chilling device in described first reaction zone, mix with any one reactant flow from the effusive Quench liquid of chilling device;

Described Quench liquid is selected from methyl alcohol or water or both mixtures.

3. method according to claim 1 is characterized in that, the temperature in of described methanol reaction zone is 250 ℃-300 ℃, and the temperature in of each moving-burden bed reactor all keeps identical in the methanol reaction zone.

4. method according to claim 1 is characterized in that, the temperature in of described first reaction zone is 450 ℃-500 ℃, and the temperature in of each moving-burden bed reactor all keeps identical in first reaction zone.

5. method according to claim 4 is characterized in that, the temperature in of described second reaction zone is higher 15 ℃-30 ℃ than the temperature in of first reaction zone, and the temperature in of each moving-burden bed reactor all keeps identical in second reaction zone.

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