MTO methanol rectification device
By constructing a main and auxiliary distillation column and a pipeline system, the gas-phase and liquid-phase switching of MTO methanol is realized, which solves the problem of high feed energy consumption in the MTO process, reduces energy consumption and cost, and expands the scope of application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHAANXI JUNENG XINCHUANG COAL CHEM TECH CO LTD
- Filing Date
- 2025-06-27
- Publication Date
- 2026-07-07
AI Technical Summary
The existing MTO process uses methanol as a feedstock for MTO, which results in high energy consumption and increased input costs.
An MTO methanol distillation unit is formed by a main distillation column, a secondary distillation column, a gaseous MTO methanol pipeline, a liquid MTO methanol pipeline, and a product methanol pipeline. The produced gaseous MTO methanol can be directly output to the MTO process. The switching between liquid and gaseous methanol is achieved through valve control, thereby reducing energy consumption.
It reduces the energy consumption and input costs of the MTO methanol distillation process, while producing both liquid and gaseous methanol, making it widely applicable and versatile.
Smart Images
Figure CN224462283U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of methanol distillation technology and relates to an MTO methanol distillation device. Background Technology
[0002] Ethylene, propylene, and other low-carbon olefins are important basic chemical raw materials. The main methods for industrial production of low-carbon olefins include petroleum cracking and non-petroleum synthesis. Petroleum cracking primarily uses petroleum as a feedstock, involves high reaction temperatures, resulting in high production costs. In non-petroleum synthesis, the existing methanol-to-olefins (MTO) process uses methanol as a feedstock. Specifically, crude methanol is first distilled into MTO-grade methanol, then vaporized and fed into the MTO unit. The vaporized MTO methanol undergoes a dehydration reaction under the action of a catalyst, producing intermediate products such as dimethyl ether, which are further converted into low-carbon olefins. This method has a wide range of feedstock sources and low energy consumption.
[0003] Referring to patent document CN219922090U, a low-energy-consumption MTO methanol distillation device utilizing reaction heat is disclosed. In coal-to-olefins processes, single-tower distillation (called a stabilizer) is commonly used to refine MTO-grade methanol. A methanol reactor and an intermediate methanol heat exchanger are connected in a loop, which can reduce the temperature of the crude methanol at the reactor outlet while simultaneously feeding syngas, producing MTO-grade methanol from the bottom of the stabilizer. However, in existing technologies, the MTO-grade methanol produced from the bottom of the stabilizer is generally liquid-phase MTO methanol, which cannot be directly used as feed to the MTO process and requires revaporization. Furthermore, the collected MTO-grade methanol from the bottom of the stabilizer is typically cooled and stored before being used as feed to the MTO process, requiring vaporization to the gaseous phase. This results in very high energy consumption and increased investment costs. Utility Model Content
[0004] To address the technical problem of high energy consumption and increased input costs associated with using methanol as feedstock in the existing MTO process, this invention provides an MTO methanol distillation device.
[0005] This utility model mainly consists of a main distillation column, a secondary distillation column, a liquid-phase MTO methanol pipeline, a gas-phase MTO methanol pipeline, and a product methanol pipeline to form an MTO methanol distillation unit. The produced MTO gas-phase methanol can be directly output to the MTO process as feed, saving energy and greatly reducing input costs.
[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0007] An MTO methanol distillation unit includes a main distillation column, a secondary distillation column, a gas phase MTO methanol pipeline, a liquid phase MTO methanol pipeline, a product methanol pipeline, and a bottom liquid pipeline.
[0008] The main distillation column is externally connected to a feed pipeline; the middle section of the main distillation column is connected to the middle section of the auxiliary distillation column; the top of the main distillation column is divided into two paths, one connected to the upper part of the main distillation column and the other connected to the upper part of the auxiliary distillation column; the bottom of the main distillation column is connected to the liquid phase MTO methanol pipeline and the bottom liquid pipeline respectively; the top of the auxiliary distillation column is connected to the gas phase MTO methanol pipeline; and the product methanol pipeline is connected to the upper middle section of the auxiliary distillation column.
[0009] Further specified, a secondary tower top gas to MTO control valve is installed on the gas phase MTO methanol pipeline; a liquid phase methanol control valve is installed on the liquid phase MTO methanol pipeline; and a reactor liquid control valve is installed on the reactor liquid pipeline.
[0010] Further specifying, the main distillation column is externally connected to a main column top gas pipeline and a main column reflux pipeline; the main column reflux pipeline is located above the feed pipeline; the auxiliary distillation column is externally connected to an auxiliary column reflux pipeline; the top of the main distillation column is connected to the main column reflux pipeline and the auxiliary column reflux pipeline respectively through the main column top gas pipeline.
[0011] Further specified, a reflux liquid return valve to the main tower is installed on the main tower reflux pipeline; and a reflux liquid return valve to the secondary tower is installed on the secondary tower reflux pipeline.
[0012] Further specifying, the secondary column of the distillation column is externally connected to a secondary column vapor phase feed line and a secondary column top refined alcohol outflow line; the secondary column vapor phase feed line is connected to the middle of the column side of the main column of the distillation column; the secondary column top refined alcohol outflow line is located between the secondary column vapor phase feed line and the secondary column reflux line; the secondary column top refined alcohol outflow line is connected to the product methanol line, and a product methanol cooler is installed on the secondary column top refined alcohol outflow line.
[0013] Further specifying, the MTO methanol distillation unit also includes a tower top connecting valve; one end of the tower top connecting valve is connected to the gas phase MTO methanol pipeline and the auxiliary tower top gas pipeline respectively, and the other end of the tower top connecting valve is connected to the main tower top gas pipeline.
[0014] Further specifying, the MTO methanol distillation unit also includes a top condenser, a reflux tank, and a reflux pump; one end of the top condenser is connected to the top of the main distillation column, and the other end of the top condenser is connected to the main column reflux line and the auxiliary column reflux line respectively via the reflux tank and the reflux pump.
[0015] Further specifying, the MTO methanol distillation unit also includes an oil-water separator and a non-oil phase return pump; an oil drain line is also provided on the lower part of the upper side of the main distillation column; the oil drain line is connected to the column side of the main distillation column after passing through the oil-water separator and the non-oil phase return pump.
[0016] Further specifying, the MTO methanol distillation unit also includes a waste heat reboiler and a column bottom reboiler; the waste heat reboiler is located above the column bottom reboiler; both ends of the waste heat reboiler and both ends of the column bottom reboiler are connected to different positions on the side of the main distillation column.
[0017] Compared with the prior art, the technical advantages of this utility model are:
[0018] 1. This utility model mainly consists of a main distillation column, a secondary distillation column, a liquid-phase MTO methanol pipeline, a gas-phase MTO methanol pipeline, and a product methanol pipeline to form an MTO methanol distillation unit. On the one hand, the produced MTO gas-phase methanol can be directly output to the MTO process as feed; and compared with the existing MTO methanol that is first vaporized and then fed, it greatly reduces energy consumption and input costs, achieving the purpose of energy saving and cost reduction. On the other hand, this utility model can simultaneously produce liquid-phase MTO methanol, gas-phase MTO methanol, and product methanol, with a wide range of applications and strong versatility.
[0019] 2. This utility model achieves switching between three different products—liquid-phase MTO methanol, gas-phase MTO methanol, and bottom liquid—by switching between the control valves for MTO from the top gas of the auxiliary tower, the control valve for liquid phase methanol, and the control valve for bottom liquid, making operation convenient.
[0020] 3. This utility model sets a reflux liquid return valve to the main tower on the main tower reflux pipeline and a reflux liquid go to the secondary tower on the secondary tower reflux pipeline; by adjusting the valve opening of the reflux liquid return valve to the main tower and the valve opening of the reflux liquid go to the secondary tower, the product methanol and liquid MTO methanol can be controlled.
[0021] 4. This utility model allows for the replacement and exhaust of the MTO methanol distillation unit during startup by setting a top-of-the-line connecting valve; it can also control the top gas of the distillation column according to the feed requirements of the downstream MTO process, ensuring stable system operation.
[0022] In summary, the MTO methanol distillation device of this invention can directly feed the generated gaseous MTO methanol into the MTO process, which not only saves energy and reduces consumption, but also reduces cost input; it can also produce liquid MTO methanol and product methanol through the control of various valves, and has a wide range of applications and strong versatility. Attached Figure Description
[0023] Figure 1 A schematic diagram of an MTO methanol distillation apparatus provided by this utility model;
[0024] in:
[0025] V1—Reflux tank; E1—Top condenser; T1—Main distillation column; 101—Feed line; 102—Top gas line of main column; 103—Reflux line of main column; 104—Reflux line of auxiliary column; 105—Gas feed line of auxiliary column; 106—Oil discharge line; 107—Boiler outlet line of main column; T2—Auxiliary distillation column; 201—Top gas line of auxiliary column; 202—Top refined alcohol collection line of auxiliary column; 203—Auxiliary column Bottom liquid phase return to main tower pipeline; E4—Product methanol cooler; V2—Oil-water separator; P1—Reflux pump; 11—Top pressure control valve; 12—Reflux liquid return to main tower valve; 13—Reflux liquid to auxiliary tower valve; 14—Bottom liquid control valve; 15—Liquid phase methanol control valve; 16—Top device connecting valve; 21—Auxiliary tower top gas to MTO control valve; P2—Non-oil phase return pump; E3—Waste heat reboiler; E2—Bottom reboiler. Detailed Implementation
[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.
[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0028] See Figure 1 In one embodiment of this utility model, an MTO methanol distillation apparatus includes a main distillation column T1, a secondary distillation column T2, a gas phase MTO methanol pipeline, a liquid phase MTO methanol pipeline, a product methanol pipeline, and a bottom liquid pipeline.
[0029] Specifically, a feed line 101 is connected to the main distillation column T1. The middle part of the side of the main distillation column T1 is connected to the middle part of the side of the auxiliary distillation column T2. The top of the main distillation column T1 is divided into two paths: one path is connected to the upper part of the side of the main distillation column T1, and the other path is connected to the upper part of the side of the auxiliary distillation column T2. The bottom of the main distillation column T1 is connected to the liquid phase MTO methanol line and the bottom liquid line, respectively. The top of the auxiliary distillation column T2 is connected to the gas phase MTO methanol line. The product methanol line is connected to the middle and upper part of the side of the auxiliary distillation column T2.
[0030] In practice, feed line 101 is used to feed raw material methanol (crude methanol) into the main column T1 of the distillation column. Crude methanol is a product from methanol synthesis. When the amount of raw material crude methanol fed is small, liquid MTO methanol stored in the liquid MTO methanol warehouse can also be sent to feed line 101. On the one hand, this reduces the storage level of liquid MTO methanol, and on the other hand, it can smooth and regulate the load changes of the methanol synthesis and MTO distillation units. At the same time, when liquid MTO methanol enters feed line 101, it increases the production load of the MTO distillation unit and can also increase the output of downstream low-carbon olefins.
[0031] Specifically, the main distillation column T1 is used to distill and dehydrogenate the raw material methanol. The resulting gaseous components are discharged from the top of the main distillation column T1 and then refluxed to the upper side of both the main distillation column T1 and the secondary distillation column T2 for further distillation to improve distillation efficiency. The heavy components (bottom liquid phase) produced in the bottom of the main distillation column T1 are discharged from the bottom of the main distillation column T1 and collected through the liquid phase MTO methanol pipeline or the bottom liquid pipeline. The mixed components from the middle of the main distillation column T1 enter the secondary distillation column T2 for further distillation and dehydrogenation. The resulting gaseous components, namely gaseous MTO methanol, are discharged from the top of the secondary distillation column T2 and then directly fed into the MTO process through the gaseous MTO methanol pipeline. At the same time, the bottom liquid produced in the secondary distillation column T2 is refluxed to the middle side of the main distillation column T1 for recycling distillation.
[0032] In implementation, when the vaporous MTO methanol produced at the top of the sub-tower T2 is fed into the MTO process or when product methanol is collected from the side of the sub-tower T2, the bottom liquid phase discharged from the bottom of the main distillation tower T1 is the bottom liquid, which is collected through the bottom liquid pipeline. When the vaporous MTO methanol produced at the top of the sub-tower T2 is not fed into the process or when a small amount of product methanol is collected from the side of the sub-tower T2, the bottom liquid phase discharged from the bottom of the main distillation tower T1 is the liquid MTO methanol, which is collected and stored through the liquid MTO methanol pipeline. This utility model's MTO methanol distillation device can produce vaporous MTO methanol that can be directly fed into the MTO process, or it can produce liquid MTO methanol and product methanol, making it widely applicable and highly versatile. Compared to traditional MTO methanol distillation and revaporization feeding, energy consumption and costs are significantly reduced.
[0033] In this embodiment, a secondary tower top gas to MTO control valve 21 is installed on the gas phase MTO methanol pipeline; the start and stop of the delivery of gas phase MTO methanol to the feed end of the MTO process and the flow rate are controlled by the secondary tower top gas to MTO control valve 21.
[0034] In this embodiment, a liquid-phase methanol control valve 15 is installed on the liquid-phase MTO methanol pipeline; a bottom liquid control valve 14 is installed on the bottom liquid pipeline. During operation, the liquid-phase methanol control valve 15 and the bottom liquid control valve 14 are one open and one closed, thereby controlling whether the heavy components generated in the bottom of the main column T1 of the distillation column are discharged into the liquid-phase MTO methanol pipeline or collected in the bottom liquid pipeline.
[0035] See Figure 1 In this embodiment of the invention, the main distillation column T1 is externally connected to a main column top gas pipeline 102 and a main column reflux pipeline 103; the main column reflux pipeline 103 is located above the feed pipeline 101; the auxiliary distillation column T2 is externally connected to an auxiliary column reflux pipeline 104; the top of the main distillation column T1 is connected to the main column reflux pipeline 103 and the auxiliary column reflux pipeline 104 through the main column top gas pipeline 102.
[0036] See Figure 1 In this embodiment of the present invention, the secondary column T2 of the distillation column is also externally connected to a secondary column gas phase feed pipeline 105 and a secondary column top refined alcohol collection pipeline 202; the secondary column top refined alcohol collection pipeline 202 is located between the secondary column gas phase feed pipeline 105 and the secondary column reflux pipeline 104; the secondary column top refined alcohol collection pipeline 202 is connected to the product methanol pipeline, and a product methanol cooler E4 is installed on the secondary column top refined alcohol collection pipeline 202.
[0037] Specifically, a main column reflux line 103 is connected above the feed line 101 of the main column T1, and a secondary column reflux line 104 is connected above the secondary column gas feed line 105 of the secondary column T2. The main column overhead gas line 102 is used to discharge the gas components generated in the main column T1 and return them to the main column reflux line 103 and the secondary column reflux line 104, respectively, and finally enter the main column T1 and the secondary column T2 for distillation and dehydrogenation.
[0038] Preferably, the position where the secondary column gas phase feed line 105 connects to the middle of the main column T1 is lower than the feed position of the main column T1 feed line 101, that is, the outlet position of the main column T1 is lower than the feed position of the main column T1 feed line. The secondary column gas phase feed line 105 is used to transport the mixed components from the middle of the main column T1 to the middle of the secondary column T2 as feed; the secondary column overhead gas line 201 is used to discharge the gas components generated in the secondary column T2 to the gas phase MTO methanol line; the secondary column bottom liquid phase return line 203 is used to return the bottom liquid generated in the secondary column T2 to the middle of the main column T1.
[0039] Preferably, the top methanol collection line 202 of the sub-tower is used to discharge the methanol component generated on the side of the sub-tower T2 of the distillation tower, and the generated methanol component is cooled by the product methanol cooler E4 to obtain the methanol product.
[0040] Preferably, a reflux liquid return valve 12 is installed on the main column reflux line 103; and a reflux liquid return valve 13 is installed on the auxiliary column reflux line 104. The reflux liquid return valve 12 is used to control the flow rate of condensate returning to the main column T1 of the distillation column; and the reflux liquid return valve 13 is used to control the flow rate of condensate returning to the auxiliary column T2 of the distillation column.
[0041] In this embodiment, a main column bottom outlet pipeline 107 is externally connected to the bottom of the main column T1 of the distillation column, which is used to discharge the heavy components produced by the main column T1 into the liquid phase MTO methanol pipeline or into the bottom liquid pipeline. Preferably, the main column bottom outlet pipeline 107 is connected to both the liquid phase MTO methanol pipeline and the bottom liquid pipeline.
[0042] See Figure 1 In one embodiment of this utility model, the MTO methanol distillation unit further includes a top gas exchange valve 16; one end of the top gas exchange valve 16 is connected to the gas phase MTO methanol pipeline and the secondary tower top gas pipeline 201 respectively, and the other end of the top gas exchange valve 16 is connected to the main tower top gas pipeline 102.
[0043] In implementation, on the one hand, the function of the overhead valve 16 is to adjust the stability of the MTO methanol distillation unit during initial start-up. Specifically, when the MTO distillation unit starts working (i.e., start-up), the overhead valve 16 is opened, causing the gas components at the top of the auxiliary column T2 to be divided into two parts: one part is sent to the MTO control valve 21 through the auxiliary column overhead gas and delivered to the MTO process, and the other part is merged into the main column overhead gas pipeline 102 through the overhead valve 16 and enters the overhead condenser E1. At this time, the MTO distillation unit completes exhaust gas replacement through the overhead valve 16, ensuring the stable operation of the entire unit; once stable, the overhead valve 16 is closed. On the other hand, when the feed is stopped in the downstream MTO process, the overhead gas generated in the distillation column T2 is collected into the overhead gas pipeline 102 of the main column through the overhead valve 16, and then enters the main column reflux pipeline 103 and the secondary column reflux pipeline 104 respectively, and flows back to the main column T1 and the secondary column T2 of the distillation column.
[0044] See Figure 1 In one embodiment of this utility model, the MTO methanol distillation unit further includes a top condenser E1, a reflux tank V1, and a reflux pump P1; one end of the top condenser E1 is connected to the top of the main distillation column T1, and the other end of the top condenser E1 is connected to the main column reflux line 103 and the auxiliary column reflux line 104 via the reflux tank V1 and the reflux pump P1, respectively.
[0045] The function of the top condenser E1 is to condense the top gas entering or flowing into the top gas pipeline 102 of the main column. The top condenser E1 is also connected to a vent pipeline, and a top pressure control valve 11 is installed on the vent pipeline. On the one hand, the non-condensable gas after being condensed by the top condenser E1 is directly vented through the top pressure control valve 11, thereby adjusting the pressure of the main distillation column T1 and the auxiliary distillation column T2. The function of the reflux pump P1 is to facilitate the return of the condensate after being condensed by the top condenser E1 to the main distillation column T1 and the auxiliary distillation column T2, respectively. That is, the condensate is returned to the main distillation column T1 through the main column reflux pipeline 103, and the condensate is returned to the auxiliary distillation column T2 through the auxiliary column reflux pipeline 104.
[0046] See Figure 1 In one embodiment of this utility model, the MTO methanol distillation unit further includes an oil-water separator V2 and a non-oil phase return pump P2; an oil drain line 106 is also provided at the lower part of the main column T1 of the distillation column; the oil drain line 106 is connected to the side of the main column T1 of the distillation column after passing through the oil-water separator V2 and the non-oil phase return pump P2.
[0047] In practice, an oil phase mixture is generated at the lower part of the main column T1 of the distillation column. Therefore, the oil phase mixture is discharged through the oil drain line 106 and separated by the oil-water separator V2. The oil phase product is then discharged from the oil-water separator V2 and collected outside the system. The remaining mixture is returned to the main column T1 of the distillation column from below or above the oil drain line 106 after passing through the non-oil phase return pump P2, so as to continue to participate in the reaction. The oil phase mixture is discharged through the oil-water separator V2 and the oil drain line 106 to ensure that the bottom liquid of the main column T1 of the distillation column is discharged in a qualified manner.
[0048] See Figure 1 In one embodiment of this utility model, the MTO methanol distillation unit further includes a waste heat reboiler E3 and a column bottom reboiler E2; the waste heat reboiler E3 is located above the column bottom reboiler E2; both ends of the waste heat reboiler E3 and both ends of the column bottom reboiler E2 are connected to different positions on the side of the main column T1 of the distillation column.
[0049] In practice, the purpose of the waste heat reboiler E3 and the reboiler E2 is to provide the heat energy required for distillation and dehydrogenation in the main distillation column T1, ensuring that the raw material methanol in the main distillation column T1 can be effectively separated and distilled. The connection and working principle of the waste heat reboiler E3 and the reboiler E2 to the main distillation column T1 are existing technologies. Preferably, the waste heat reboiler E3 and the reboiler E2 are located on opposite sides of the main distillation column T1, with one end of the reboiler E2 connected to the main column reboiler outlet pipeline 107 at the bottom of the main distillation column T1. In use, the by-product steam of the MTO process is used as the heat source for the waste heat reboiler E3 and the reboiler E2, achieving heat reuse and saving energy.
[0050] The first working process of the MTO methanol distillation apparatus provided by this utility model is as follows: when gaseous MTO methanol is supplied to the MTO process through the gaseous MTO methanol pipeline, the control valve 21 for the gas from the top of the auxiliary tower to MTO is closed. The raw material methanol enters the main distillation column T1 through feed line 101 for distillation and removal of light components. The resulting gaseous components are discharged from the top of the main distillation column T1 through the main column overhead gas line 102 and flow into the overhead condenser E1 for heat exchange and condensation. The non-condensable gases are then directly discharged through the overhead pressure control valve 11. The condensate enters the reflux tank V1 and is divided into two streams after passing through the reflux pump P1. One stream of condensate is refluxed back to the main distillation column T1 through the main column reflux line 103, and the other stream is refluxed back to the secondary distillation column T2 through the secondary column reflux line 104. The mixed components exiting from the middle of the main distillation column T1 enter the secondary distillation column T2 through the secondary column gas phase feed line 105 for further dehydrogenation. The resulting gaseous components are discharged from the top of the secondary distillation column T2 through the secondary column overhead gas line 201, thus obtaining the gas phase. MTO methanol is then directly transported to the feed end of the subsequent MTO process via the gas phase MTO methanol pipeline. At the same time, some methanol product is generated on the side of the sub-tower T2 of the distillation column and is collected from the refined methanol collection pipeline 202 at the top of the sub-tower. After being cooled by the product methanol cooler E4, refined methanol product is obtained. The bottom liquid generated at the bottom of the sub-tower T2 flows back to the middle of the side of the main distillation column T1 via the bottom liquid return pipeline 203 for circulating distillation. Since the gas phase MTO methanol generated at this time is directly transported to the downstream MTO process, the main component of the heavy component generated at the bottom of the main distillation column T1 is mainly the bottom liquid. Therefore, the bottom liquid control valve 14 is opened and the liquid phase methanol control valve 15 is closed. The heavy component is discharged from the bottom of the main distillation column T1 via the main column bottom discharge pipeline 107 and flows into the bottom liquid pipeline for collection.
[0051] The second operating process of the MTO methanol distillation apparatus provided by this utility model is as follows: When gaseous MTO methanol is not required in the subsequent MTO process, the control valve 21 for the top gas to MTO of the auxiliary column is closed, and the overhead gas connecting valve 16 is opened. At this time, the main distillation column T1 still operates in the above manner. The difference is that after the material in the auxiliary column T2 is de-lightened, the generated gas components flow from the top of the auxiliary column T2 through the overhead gas connecting valve 16 into the top gas pipeline 102 of the main column and enter the top condenser E1. After condensation... The condensate enters the reflux tank V1 and is divided into two streams for reflux after passing through the reflux pump P1. Methanol is produced at the top of the secondary column T2 on the side of the distillation column. At the same time, the heavy component produced in the bottom of the main column T1 of the distillation column, whose main component is liquid MTO methanol, is discharged from the bottom of the main column T1 of the distillation column via the bottom discharge pipeline 107 and flows into the liquid MTO methanol pipeline, and then is collected in the liquid MTO methanol storage.
[0052] In both operating modes, the methanol production is controlled by adjusting the valve opening of the reflux return valve 12 to the main tower and the valve opening of the reflux to the auxiliary tower valve 13. For example, when the valve opening of the reflux return valve 12 to the main tower is reduced and the valve opening of the reflux to the auxiliary tower valve 13 is increased, most of the condensate after being condensed by the top condenser E1 flows back to the auxiliary distillation tower T2 through the auxiliary tower reflux pipeline 104. At this time, the methanol production at the auxiliary tower top methanol outlet pipeline 202 on the auxiliary tower side of the auxiliary distillation tower T2 is relatively high. Conversely, the methanol production at the auxiliary tower top methanol outlet pipeline 202 on the auxiliary tower side of the auxiliary distillation tower T2 is relatively low.
[0053] The MTO methanol distillation device of this invention can directly feed the gaseous MTO methanol into the MTO process feed, which greatly reduces energy consumption and input costs compared with the traditional MTO methanol distillation and revaporation feed. At the same time, it can also produce liquid MTO methanol and refined methanol products, with a wide range of applications and strong versatility.
[0054] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. An MTO methanol distillation apparatus, characterized in that, This includes the main distillation column (T1), the auxiliary distillation column (T2), the vapor-phase MTO methanol pipeline, the liquid-phase MTO methanol pipeline, the product methanol pipeline, and the bottom liquid pipeline; The main distillation column (T1) is externally connected to a feed pipeline (101); the middle part of the side of the main distillation column (T1) is connected to the middle part of the side of the auxiliary distillation column (T2); the top of the main distillation column (T1) is divided into two paths, one of which is connected to the upper part of the side of the main distillation column (T1); the other path is connected to the upper part of the side of the auxiliary distillation column (T2); the bottom of the main distillation column (T1) is connected to the liquid phase MTO methanol pipeline and the bottom liquid pipeline respectively; the top of the auxiliary distillation column (T2) is connected to the gas phase MTO methanol pipeline; the product methanol pipeline is connected to the middle and upper part of the side of the auxiliary distillation column (T2).
2. The MTO methanol distillation apparatus according to claim 1, characterized in that, A secondary tower top gas to MTO control valve (21) is installed on the gas phase MTO methanol pipeline; a liquid phase methanol control valve (15) is installed on the liquid phase MTO methanol pipeline; and a reactor liquid control valve (14) is installed on the reactor liquid pipeline.
3. The MTO methanol distillation apparatus according to claim 2, characterized in that, The main column (T1) of the distillation column is externally connected to a main column top gas pipeline (102) and a main column reflux pipeline (103); the main column reflux pipeline (103) is located above the feed pipeline (101); the auxiliary column (T2) of the distillation column is externally connected to an auxiliary column reflux pipeline (104); the top of the main column (T1) of the distillation column is connected to the main column reflux pipeline (103) and the auxiliary column reflux pipeline (104) through the main column top gas pipeline (102).
4. The MTO methanol distillation apparatus according to claim 3, characterized in that, A reflux liquid return valve (12) is installed on the main tower reflux pipeline (103); a reflux liquid return valve (13) is installed on the auxiliary tower reflux pipeline (104).
5. The MTO methanol distillation apparatus according to claim 4, characterized in that, The distillation column sub-tower (T2) is also externally connected to a sub-tower gas phase feed line (105) and a sub-tower top refined alcohol outlet line (202); the sub-tower gas phase feed line (105) is connected to the middle of the column side of the distillation column main tower (T1); the sub-tower top refined alcohol outlet line (202) is located between the sub-tower gas phase feed line (105) and the sub-tower reflux line (104); the sub-tower top refined alcohol outlet line (202) is connected to the product methanol line, and a product methanol cooler (E4) is installed on the sub-tower top refined alcohol outlet line (202).
6. The MTO methanol distillation apparatus according to claim 5, characterized in that, The MTO methanol distillation unit also includes a top gas exchange valve (16); one end of the top gas exchange valve (16) is connected to the gas phase MTO methanol pipeline and the secondary tower top gas pipeline (201) respectively, and the other end of the top gas exchange valve (16) is connected to the main tower top gas pipeline (102).
7. The MTO methanol distillation apparatus according to claim 3, characterized in that, The MTO methanol distillation unit also includes a top condenser (E1), a reflux tank (V1), and a reflux pump (P1); one end of the top condenser (E1) is connected to the top of the main distillation column (T1), and the other end of the top condenser (E1) is connected to the main column reflux line (103) and the auxiliary column reflux line (104) via the reflux tank (V1) and the reflux pump (P1).
8. The MTO methanol distillation apparatus according to claim 7, characterized in that, The MTO methanol distillation unit also includes an oil-water separator (V2) and a non-oil phase return pump (P2); an oil drain line (106) is also provided on the lower part of the upper column side of the main distillation column (T1); the oil drain line (106) is connected to the column side of the main distillation column (T1) after passing through the oil-water separator (V2) and the non-oil phase return pump (P2).
9. The MTO methanol distillation apparatus according to any one of claims 1-8, characterized in that, The MTO methanol distillation unit also includes a waste heat reboiler (E3) and a column bottom reboiler (E2); the waste heat reboiler (E3) is located above the column bottom reboiler (E2); both ends of the waste heat reboiler (E3) and both ends of the column bottom reboiler (E2) are connected to different positions on the side of the main distillation column (T1).