Short-contact reactor, and system and method for using same in preparation of ethylene and propylene from methanol

Abstract

The present invention provides a short-contact reaction system in the preparation of ethylene and propylene from methanol. The system comprises: a methanol-to-olefin short-contact reactor, a riser reactor, a double-dense bed, and a stripper. The methanol-to-olefin short-contact reactor is used to convert methanol to olefin-rich products. The methanol-to-olefin short-contact reactor comprises a methanol feed pipeline, a filter pipe wall and a product gas channel coaxially distributed from the inside to the outside, a catalyst distributor provided at the top part of the reactor, and a material seal pipe provided at the bottom part of the reactor. The material seal pipe is located inside of the stripper. The diameter of the top part of the product gas channel is larger than the diameter of the bottom part of the product gas channel. In the present invention, methanol is in cross-flow contact with downward coking catalyst II in the methanol-to-olefin short-contact reactor, and the cross-flow contact reaction between the methanol and the catalyst under the condition of a very short contact time may obtain a product having high selectivity of ethylene and propylene. The present invention better solves the problem of low selectivity of ethylene and propylene, and may be used in MTO industrial production.

Description

The weight ratio of the mixed light hydrocarbon feed 13 to the steam was 1:1. The catalyst was SAPO-34 molecular sieve catalyst. The regenerated catalyst 5, based on the total weight of the catalyst, had a carbon content of 0.02%. The stripping medium 16 was steam. The result showed that the ethylene and propylene carbon-based selectivity reached 92.5 wt.%. Example 2 The apparatus and conditions of Example 1 were used except that the filtering precision of the filter pipe wall 8 was 30 microns. The ratio of the diameter at the top 11 of the product gas channel to the diameter at the bottom 10 of the product gas channel was 1:3, the reactor shell 27 had an angle between the side wall and the horizontal plane of 60°. The catalyst distributor 15 was a grille with the pore fraction of 95%. The filter pipe wall 8 had an average pore diameter in the upper region of 10 microns, an average pore diameter in the middle region of 20 microns, and an average pore diameter in the lower region of 30 microns. The methanol feeding pipeline 7 was located in the center of the MTO short contact reactor 1. The methanol feeding pipeline 7 had a pore fraction in the upper region of 10%, a pore fraction in the middle region of 15%, and a pore fraction in the lower region of 20%. The result showed that the ethylene and propylene carbon-based selectivity reached 91.3 wt.%. Example 3 The apparatus and conditions of Example 1 were used except that the filtering precision of the filter pipe wall 8 was 20 microns. The ratio of the diameter at the top 11 of the product gas channel to the diameter at the bottom 10 of the product gas channel was 1:1.9, the reactor shell 27 had an angle between the side wall and the horizontal plane of 70°. The catalyst distributor 15 was a grille with the pore fraction of 75%. The methanol feeding pipeline 7 was located in the center of the MTO short contact reactor 1. The methanol feeding pipeline 7 had a pore fraction in the upper region of 7%, a pore fraction in the middle region of 12%, and a pore fraction in the lower region of 18%. The filter pipe wall 8 had an average pore diameter in the upper region of 7 microns, an average pore diameter in the middle region of 15 microns, and an average pore diameter in the lower region of 25 microns. The result showed that the ethylene and propylene carbon-based selectivity reached 93.0 wt.%. Example 4 The apparatus of Example 3 was used except that in the MTO short contact reactor 1, the catalyst temperature was 450 °C, the reaction gauge pressure was 0.01 MPa, the mass space velocity of methanol was 2 h-1, and the catalyst density was 100 kg / m3. In the riser reactor 2, the catalyst temperature was 530 °C, the gas linear velocity was 1.1 m / s, the mass space velocity of the mixed light hydrocarbon feed 13 was 5 h-1 , and the catalyst density was 20 kg / m3 . In the dense bed 3, the catalyst temperature was 480 °C, the gas linear velocity was 0.3 m / s, the mass space velocity of the by-product oxide feed 20 was 0.3 h-1, and the catalyst density was 180 kg / m3. The weight ratio of the mixed light hydrocarbon feed 13 to the steam was 1:0.5. The catalyst was SAPO-34 molecular sieve catalyst. The regenerated catalyst 5, based on the total weight of the catalyst, had a carbon content of 0.09%. The stripping medium 16 was steam. The result showed that the ethylene and propylene carbon-based selectivity reached 91.4 wt.%. Example 5 The apparatus of Example 3 was used except that in the MTO short contact reactor 1, the catalyst temperature was 500 °C, the reaction gauge pressure was 0.3 MPa, the mass space velocity of methanol was 15 h-1, and the catalyst density was 400 kg / m3. In the riser reactor 2, the catalyst temperature was 650 °C, the gas linear velocity was 15 m / s, the mass space velocity of the mixed light hydrocarbon feed 13 was 30 h-1, and the catalyst density was 100 kg / m3. In the dense bed 3, the catalyst temperature was 580 °C, the gas linear velocity was 1 m / s, the mass space velocity of the by-product oxide feed 20 was 3 h-1, and the catalyst density was 400 kg / m3. The weight ratio of the mixed light hydrocarbon feed 13 to the steam was 1:3. The catalyst was SAPO-34 molecular sieve catalyst. The regenerated catalyst 5, based on the total weight of the catalyst, had a carbon content of 0.01%. The stripping medium 16 was steam. The result showed that the ethylene and propylene carbon-based selectivity reached 93.1 wt.%. Example 6 The apparatus of Example 3 was used except that in the MTO short contact reactor 1, the catalyst temperature was 490 °C, the reaction gauge pressure was 0.18 MPa, the mass space velocity of methanol was 13 h-1, and the catalyst density was 300kg / m3. In the riser reactor 2, the catalyst temperature was 580 °C, the gas linear velocity was 10 m / s, the mass space velocity of the mixed light hydrocarbon feed 13 was 23 h-1, and the catalyst density was 35 kg / m3. In the dense bed 3, the catalyst temperature was 520 °C, the gas linear velocity was 0.8 m / s, the mass space velocity of the by-product oxide feed 20 was 1.8 h-1, and the catalyst density was 300 kg / m3. The weight ratio of the mixed light hydrocarbon feed 13 to the steam was 1:2. The catalyst was SAPO-34 molecular sieve catalyst. The regenerated catalyst 5, based on the total weight of the catalyst, had a carbon content of 0.03%. The stripping medium 16 was nitrogen gas. The result showed that the ethylene and propylene carbon-based selectivity reached 94.0 wt.%. Comparative Example 1 The apparatus and conditions of Example 6 were used except that the feeding amount of the mixed light hydrocarbon feed 13 was zero, and steam was introduced into the riser reactor 2. The result showed that the ethylene and propylene carbon-based selectivity reached 85.2 wt.%. Comparative Example 2 The apparatus and conditions of Example 6 were used except that the feeding amount of the by-product oxide feed 20 was 0. The result showed that the ethylene and propylene carbon-based selectivity reached 88.4 wt.%. Comparative Example 3 The apparatus and conditions of Example 6 were used except that the ratio of the diameter at the top 1 1 of the product gas channel to the diameter at the bottom 10 of the product gas channel was 1:1. The result showed that the ethylene and propylene carbon-based selectivity reached 89.0 wt.%. Example 7 The apparatus of Example 6 was used except that in the MTO short contact reactor 1, the catalyst temperature was 520 °C, the reaction gauge pressure was 0.4 MPa, the mass space velocity of methanol was 20 h-1, and the catalyst density was 450kg / m3. The result showed that the ethylene and propylene carbon-based selectivity reached 90.3 wt.%. The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, a variety of simple modifications can be made to the technical solutions of the present invention, including the combinations of various technical features in any other suitable manners. These simple modifications and combinations should also be regarded as the disclosures content of the present invention, and all belong to the protection scope of the present invention.

Claims

1. An axial-radial short contact reactor, comprising the following components coaxially 5 distributed from inside to outside:a feeding pipeline, having a feeding port at its lower end for introducing a gaseous feedstock, and allowing the feedstock to be transported from bottom to top, wherein feeding pores are distributed on the feeding pipeline, so that the feedstock is transported outward from the feeding pipeline in a substantially radial direction;10 an axial-radial reaction space, which is defined by the inner feeding pipeline and an outer filter pipe wall, so that the feedstock transported radially outward contacts the catalyst transported axially from top to bottom in crossflow, and the gas-solid contact time is less than 3 seconds in the reaction space;a filter pipe wall, which has a certain pore diameter so that the feedstock continues to be 15 transported through pores outward and into a product gas channel, and the catalyst densityin the product gas channel is less than 10 kg / m3; anda reactor shell, which defines a product gas channel together with the filter pipe wall, and has such a shape and structure that the residence time of a product gas in the product gas channel is less than 15 seconds;20 and the reactor also has a catalyst distributor arranged at its top, which distributor has a certain pore fraction, so as to transport the catalyst by gravity from top to bottom, and allow the catalyst density in the reaction space to reach the range from 80 kg / m3 to 400 kg / m3, the reactor shell has a shape of a truncated cone, and a smaller diameter at its top, so that the ratio of the diameter at the top of the product gas channel to the diameter at the bottom25 of the product gas channel ranges from 1:1.1 to 1:3; and / or the reactor shell has an angle between the side wall and the horizontal plane of from 60° to 85°,wherein the pore fraction of the feeding pipeline and the pore diameter of the filter pipe wall allow the feedstock to achieve a gas-solid contact time of less than 2 seconds, e.g. from 0.1 seconds to 1.8 seconds in the reaction space,30 wherein the feeding pipeline has a pore fraction that gradually increases from top to bottom; the feeding pipeline has a pore fraction in the upper region of from 5% to 10%, a pore fraction in the middle region of from 10% to 15%, and a pore fraction in the lower region of from 15 to 20%,2022355370   11 Jun 2026wherein the filter pipe wall has an average pore diameter that gradually increases from top to bottom; the filter pipe wall has an average pore diameter in the upper region of from 5 microns to 10 microns, an average pore diameter in the middle region of from 10 microns to 20 microns, and an average pore diameter in the lower region of from 20 microns to 30 5 microns.

2. The reactor according to claim 1, wherein the feeding pipeline has a closed top at its upper end.10  3. The reactor according to claim 1, wherein the filter pipe wall has an average porediameter ranging from 5 microns to 30 microns.

4. The reactor according to claim 1, wherein the catalyst distributor is configured so that the reaction space has a catalyst density of greater than 100 kg / m3.

155. The reactor according to claim 1, wherein the catalyst distributor is configured so that the reaction space has a catalyst density of greater than 150 kg / m3.

6. The reactor according to claim 1, wherein the catalyst distributor is a grille or porous 20 baffle with a pore fraction ranging from 60% to 95%.

7. The reactor according to claim 1, wherein the feeding pipeline has a pore fraction ranging from 5% to 20%.25  8. A short contact reaction system for preparing ethylene and propylene from methanol,comprising: a short contact reactor according to any one of claims 1-7, a riser reactor, a dense bed, and a stripper;the short contact reactor is used to convert methanol to an olefin-rich product;the riser reactor is used to convert a mixed light hydrocarbon feed, including a mixture of 30  C4-C6 non-aromatic hydrocarbons from the product of the short contact reactor, into anolefin-rich product, which ascends into the dense bed;the dense bed is arranged above the short contact reactor, and is used to store and provide a catalyst required by the short contact reactor and convert a by-product oxide feed from2022355370   11 Jun 2026the reaction product;the stripper is arranged below the short contact reactor and is used to remove a reaction product entrained by the coked catalyst from the short contact reactor.5  9. The reaction system according to claim 8, whereina cyclone separator is arranged in the dense bed; and / orthe reaction system further comprises a catalyst flow controller, which connects to the dense bed and the short contact reactor; and / orthe reaction system further comprises a separation system, which is used to separate the 10 reaction product from the dense bed and / or the short contact reactor (1) into ethylene, propylene, and a mixture of C4-C6 non-aromatic hydrocarbons.

10. The reaction system according to claim 9, whereinthe catalyst flow controller is a solid kicking device, a slide valve or a plug valve. 1511. A process for producing ethylene and propylene from methanol through a short contact reaction, wherein said process is performed using the reaction system according to any one of claims 8-10, and comprises:a) rendering a methanol feedstock to enter an short contact reactor via a methanol feeding 20 pipeline, and contact and react with a descending catalyst to produce a methanol reaction product and a coked catalyst I; rendering the methanol reaction product to enter a product gas channel via a filter pipe wall, leave the short contact reactor and merge into a reaction product; rendering the coked catalyst to descend into a stripper via a seal pipe;b) rendering a mixed light hydrocarbon feed and a steam to enter a riser reactor, contact 25 and react with a regenerated catalyst, and ascend into a dense bed;c) rendering a by-product oxide feed to enter the dense bed, and contact and react with a catalyst to produce a reaction product and a coked catalyst n; rendering the coked catalyst II to enter the short contact reactor via a catalyst flow controller and a catalyst distributor; d) rendering a stripping medium to enter a stripper and contact the catalyst to perform 30 stripping; rendering the resulting stripped product to merge into the reaction product and the resulting spent catalyst to enter a regenerator for regeneration to produce a regenerated catalyst;e) rendering the reaction product to enter a subsequent separation system for separation to2022355370   11 Jun 2026produce a mixed light hydrocarbon feed and a by-product oxide feed .

12. The process according to claim 11, whereinthe mixed light hydrocarbon feed at least includes a mixture of C4-C6 non-aromatic 5 hydrocarbons obtained from the separation system; and / orthe by-product oxide feed is composed of a by-product mixed oxide and water as generated from the reaction,wherein the mixed oxide is comprised in an amount ranging from 5% to 80%, the mixed oxide contains methanol and at least one of ethanol, propanol, butanol, ethanal, propanal, 10 butanal, acetone, butanone, formic acid, acetic acid, and propionic acid, wherein thealdehydes and ketones are comprised in an amount ranging from 30% to 60% in the mixed oxide, and methanol is comprised in an amount ranging from 0.01% to 30% in the mixed oxide.15   13. The process according to claim 11 or 12, whereinthe operation conditions in the short contact reactor includes:the catalyst temperature: 450-500 °C,the reaction gauge pressure: 0.01-0.3 MPa,the mass space velocity of methanol: 2-15 h-1,20 the catalyst density: 100-400 kg / m3; and / orthe operation conditions in the riser reactor includes:the catalyst temperature: 530-650 °C,the gas linear velocity: 1.1-15 m / s,the mass space velocity of the mixed light hydrocarbon feed: 5-30 h-1,25 the catalyst density: 20-100 kg / m3; and / orthe operation conditions in the dense bed includes:the catalyst temperature: 480-580 C,the gas linear velocity: 0.3-1 m / s,the mass space velocity of the by-product oxide feed: 0.3-3 h-1,30 the catalyst density: 180-400 kg / m3.

14. The process according to claim 11 or 12, whereinthe weight ratio of the mixed light hydrocarbon feed to the steam ranges from 1:0.5 to 1:3;2022355370   11 Jun 2026and / orthe catalyst is SAPO-34 molecular sieve catalyst; and / orthe regenerated catalyst, based on the total weight of the catalyst, has a carbon content of less than 0.1%; and / or5 the stripping medium is one or more of steam and inert gases.

Images