System for preparing methanol from natural gas
By optimizing the two-stage conversion process and high-temperature combustion, the problems of low conversion rate and high energy consumption in small-scale natural gas-to-methanol production have been solved, achieving efficient methane utilization and low-energy production.
Patent Information
- Application Number
- CN202520534692.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-03-25
AI Technical Summary
Traditional natural gas to methanol processes suffer from problems such as low conversion rate, high energy consumption, and high equipment cost in small-scale production. Furthermore, the H/C ratio in the syngas is unsuitable, resulting in low methane utilization.
A two-stage conversion process is adopted, which uses the high temperature of syngas to heat and convert the feed gas and natural gas. Combined with the evaporation and vaporization of demineralized water, heat energy is recovered. Oxygen and water vapor are introduced into the combustion section for high-temperature combustion to promote deep conversion and optimize the composition ratio of syngas.
It reduces energy consumption, improves conversion rate and methane utilization rate, reduces methane content, has fewer system devices, a compact structure, and low operating energy consumption.
Smart Images
Figure CN223915379U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of chemical equipment, specifically relates to a natural gas methanol system. BACKGROUND
[0002] The traditional natural gas methanol process is mostly one-stage conversion, and is mostly suitable for large-scale production equipment, and there are problems such as low conversion rate, high energy consumption, poor economic benefit and the like when used for small-scale production, and the H / C ratio in the synthetic gas prepared is large (H is more than C), the residual methane content reaches about 5%, and the methane utilization rate is low. At present, the one-stage conversion is changed into two-stage conversion for natural gas methanol, although it can well adapt to small-scale production, but there are still problems such as low conversion rate, high energy consumption and equipment cost. UTILITARY MODEL
[0003] In view of the deficiencies existing in the prior art, the utility model provides a natural gas methanol system, the system utilizes the high temperature of synthetic gas to sequentially heat and convert raw material gas, heat natural gas and evaporate and vaporize desalted water, fully recycles and utilizes the heat energy of synthetic gas, and reduces energy consumption; at the same time, the raw material gas is pre-converted and heated in the heat exchange conversion section, then enters the combustion section to burn and enters the two-stage conversion section to high-temperature conversion, so that the combustion and two-stage conversion temperature is higher, and the conversion is more sufficient; the system has the advantages of less equipment, low running energy consumption, compact synthetic tower structure and the like.
[0004] To achieve the above object, the utility model adopts the technical scheme as follows:
[0005] A natural gas methanol system, comprising:
[0006] A conversion tower;
[0007] A first heat exchanger, the hot medium inlet of the first heat exchanger is connected with the synthetic gas outlet of the conversion tower, the cold medium inlet is connected with a natural gas source, and the cold medium outlet is connected to the raw material gas inlet of the conversion tower;
[0008] A second heat exchanger, the hot medium inlet of the second heat exchanger is connected with the hot medium outlet of the first heat exchanger, the cold medium inlet is connected with a desalted water source, and the cold medium outlet is connected to the raw material gas inlet of the conversion tower;
[0009] Wherein, the conversion tower comprises a heat exchange conversion section, a combustion section and a two-stage conversion section, the heat exchange conversion section is connected with the inlet end of the combustion section and the outlet end of the two-stage conversion section, and the raw material gas inlet and the synthetic gas outlet are both arranged in the heat exchange conversion section.
[0010] In an embodiment of the present application, a natural gas purifier is further included, an inlet of the natural gas purifier is connected to an outlet of the cold medium of the first heat exchanger, and an outlet of the natural gas purifier is connected to an inlet of the raw gas of the conversion tower.
[0011] In an embodiment of the present application, an oxygen source pipeline is further provided, and the oxygen source pipeline is connected to an inlet end of the combustion section.
[0012] In an embodiment of the present application, an outlet of the cold medium of the second heat exchanger is further connected to the inlet end of the combustion section through a branch pipeline.
[0013] In an embodiment of the present application, a steam drum is further provided, an inlet end of the steam drum is connected to the outlet of the cold medium of the second heat exchanger, and an outlet end of the steam drum is connected to the inlet of the raw gas of the conversion tower and the inlet end of the combustion section.
[0014] In an embodiment of the present application, the inlet end of the combustion section is provided with a burner, and the oxygen source pipeline and the branch pipeline of the outlet of the cold medium of the second heat exchanger are both connected to the burner.
[0015] In an embodiment of the present application, the heat exchange conversion section, the second conversion section and the combustion section of the conversion tower are sequentially arranged from top to bottom.
[0016] Alternatively,
[0017] The combustion section, the second conversion section and the heat exchange conversion section of the conversion tower are sequentially arranged from top to bottom.
[0018] In an embodiment of the present application, a pre-conversion channel of the heat exchange conversion section is in communication with the inlet of the raw gas and the outlet of the pre-conversion gas, a heat exchange channel of the heat exchange conversion section is in communication with the outlet end of the second conversion section and the outlet of the synthesis gas, and the outlet of the pre-conversion gas is connected to the inlet end of the combustion section through a pre-conversion gas pipeline.
[0019] In an embodiment of the present application, the second conversion section and the pre-conversion channel are both filled with a catalyst layer.
[0020] In an embodiment of the present application, a cooler, a gas-liquid separator, a compressor and a methanol synthesis device are sequentially arranged, and an inlet end of the cooler is connected to the outlet end of the hot medium of the second heat exchanger.
[0021] Compared with the prior art, the present application has the following beneficial effects:
[0022] 1. The natural gas to methanol system of the application, which utilizes the high temperature of the synthesis gas to sequentially heat and convert the raw gas, heat the natural gas, and evaporate and vaporize the desalted water, fully recycles and utilizes the heat energy of the synthesis gas, and reduces the energy consumption; meanwhile, the raw gas is pre-converted and heated in the heat exchange conversion section, then enters the combustion section for combustion and the second conversion section for high temperature conversion, which can make the combustion and second conversion temperature higher, the conversion reaction speed faster, and the conversion more complete; the system has the advantages of less equipment, low operation energy consumption, compact synthesis tower structure, etc.
[0023] 2. The application introduces oxygen and water vapor in the combustion section, which can further promote deep conversion, improve the utilization rate of methane, reduce the content of methane and other inert components, and reduce the methane content to below 0.5% by utilizing pure oxygen to participate in combustion and high temperature reaction; the introduction of oxygen mixed with water vapor can increase the proportion of this part of mixed gas, make the distribution of oxygen and pre-converted gas more uniform when they contact, make the combustion more stable, and at the same time make the combustion reaction better controlled, and when the oxygen is cut off, the water vapor is a fire extinguishing agent, which can quickly control the combustion temperature in the combustion section. BRIEF DESCRIPTION OF DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.
[0025] Fig. 1 It is a structural schematic view of the natural gas to methanol system of one embodiment in the application.
[0026] Fig. 2 It is a structural schematic view of the conversion tower in the natural gas to methanol system of one embodiment.
[0027] Fig. 3 It is a structural schematic view of the natural gas to methanol system of another embodiment in the application.
[0028] Reference signs:
[0029] 1. Conversion tower; 11. Heat exchange conversion section; 111. Pre-conversion channel; 112. Heat exchange channel; 12. Combustion section; 121. Burner; 13. Second conversion section; 14. Pre-converted gas pipeline;
[0030] 2. First heat exchanger;
[0031] 3. Second heat exchanger;
[0032] 4. Natural gas purifier;
[0033] 5, bubble; 51, branch pipe;
[0034] 6, oxygen source pipe;
[0035] 7, cooler; 71, gas-liquid separator; 72, compressor; 73, methanol synthesis device. DETAILED DESCRIPTION
[0036] Hereinafter, only certain exemplary embodiments are simply described. As can be appreciated by those skilled in the art, the described embodiments can be modified in various different manners without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.
[0037] In the description of the present application, it is to be understood that the terms "vertical", "upper", "lower", "top", "bottom", "inner", "outer" and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.
[0038] The terms "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.
[0039] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected, or it can be communicated; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0040] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can include direct contact between the first and second features, or indirect contact between the first and second features through another feature therebetween. Moreover, the first feature "on", "above" and "over" the second feature includes the first feature directly above and obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "under", "below" and "underneath" the second feature includes the first feature directly below and obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.
[0041] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.
[0042] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.
[0043] As Figs. 1 to 3 shown, the embodiment of the present application provides a natural gas methanol system, which comprises a conversion tower 1, a first heat exchanger 2 and a second heat exchanger 3.
[0044] The conversion tower 1 comprises a heat exchange conversion section 11, a combustion section 12 and a two-stage conversion section 13, the heat exchange conversion section 11 is connected with the inlet end of the combustion section 12 and the outlet end of the two-stage conversion section 13, and the raw material gas inlet and the synthesis gas outlet are both arranged at the heat exchange conversion section 11.
[0045] The first heat exchanger 2 has a hot medium channel and a cold medium channel, the hot medium inlet of the second heat exchanger 2 is connected with the synthesis gas outlet of the conversion tower 1 through a pipeline; the cold medium inlet of the second heat exchanger 2 is connected with a natural gas source, and the cold medium outlet is connected to the raw material gas inlet of the conversion tower 1. By arranging the second heat exchanger 2, the heat carried by the synthesis gas discharged from the synthesis tower 1 is recycled to preheat the natural gas raw material.
[0046] The second heat exchanger 3 also has a hot medium channel and a cold medium channel, the hot medium inlet of the second heat exchanger 3 is connected with the hot medium outlet of the first heat exchanger 2 through a pipeline; the cold medium inlet of the second heat exchanger 3 is connected with a desalted water source through a pipeline, and the cold medium outlet is connected to the raw material gas inlet of the conversion tower 1. Further utilize the heat carried by the synthesis gas of the conversion tower 1 to preheat the desalted water, so that the desalted water vaporizes and vaporizes, and the preheated desalted water vapor and the preheated natural gas enter the heat exchange conversion section 11 of the synthesis tower 1 for heat exchange conversion reaction.
[0047] Preferably, a booster pump is arranged between the desalted water source and the second heat exchanger 3, and the desalted water enters the second heat exchanger 3 after being pressurized by the booster pump, so that the heat energy of the synthesis gas can be more fully recovered and utilized, and a sufficient desalted water vapor source can be provided.
[0048] The natural gas and the desalted water vapor are mixed in the heat exchange conversion section 11 to perform a heating pre-conversion reaction, the mixed gas after the pre-conversion reaction (i.e. pre-converted gas) is discharged to the combustion section 12 to perform combustion, the high-temperature gas after the combustion enters the secondary conversion section 13 to perform a high-temperature catalytic conversion reaction, so as to realize deep conversion and obtain high-temperature synthesis gas, and the high-temperature synthesis gas further heats the raw material gas (the mixed gas of the natural gas and the desalted water vapor) in the heat exchange conversion section 11, so as to realize recovery and utilization of the heat energy of the high-temperature synthesis gas and heating of the pre-conversion.
[0049] The system for producing methanol from natural gas according to the present application utilizes the high temperature of the synthesis gas to sequentially heat and convert the raw material gas, heat the natural gas, and evaporate and vaporize the desalted water, so that the heat energy of the synthesis gas is fully recovered and utilized, and the energy consumption is reduced; meanwhile, the raw material gas is pre-converted and heated in the heat exchange conversion section 11, and then enters the combustion section 12 to perform combustion and enters the secondary conversion section 13 to perform high-temperature conversion, so that the combustion and secondary conversion temperature is higher, the conversion reaction speed is faster, and the conversion is more complete; the system has the advantages of fewer devices, low running energy consumption, compact structure of the synthesis tower 1, etc.
[0050] Further, the system for producing methanol from natural gas further comprises a natural gas purifier 4, which is arranged between the first heat exchanger 2 and the raw material gas inlet of the conversion tower 1 through a pipeline connection, the inlet of the natural gas purifier 4 is connected to the cold medium outlet of the first heat exchanger 2 through a pipeline, and the outlet of the natural gas purifier 4 is connected to the raw material gas inlet of the conversion tower 1 through a pipeline. The preheated natural gas enters the natural gas purifier 4, and at this temperature, the substances harmful to the conversion catalyst, such as H2S, etc., present in the natural gas can be effectively removed, so as to ensure efficient conversion of the conversion tower 1.
[0051] Preferably, the system for producing methanol from natural gas further comprises an oxygen source pipeline 6 connected to the inlet end of the combustion section 12 of the conversion tower 1, so that oxygen is mixed with the pre-converted gas to perform combustion. The oxygen source pipeline 6 introduces pure oxygen into the combustion section 12 of the system to participate in combustion and secondary conversion, which not only can adjust the H / C ratio of the synthesis gas to a more suitable ratio, but also can make the conversion temperature higher, greatly reduce the content of residual methane in the converted synthesis gas, improve the utilization rate of methane in the natural gas, reduce the content of inert components in the methanol synthesis gas, and improve the synthesis efficiency of the entire system.
[0052] Further, the second heat exchanger 3 cold medium outlet discharge direction of the natural gas to methanol system is also provided with a branch pipeline 51, which is connected to the inlet end of the combustion section 12. That is, a part of the preheated desalted water vapor enters the heat conversion section 11, and the other part enters the combustion section 12 to participate in combustion. Preferably, the desalted water vapor is mixed with pure oxygen to enter the combustion section 12 to participate in combustion. Mixing desalted water vapor in oxygen can better control the combustion reaction. When the oxygen is cut off, the desalted water vapor is a fire extinguishing agent, which can quickly control the combustion temperature in the converter; at the same time, mixing desalted water vapor in oxygen can increase the proportion of the mixed gas, and make the oxygen and pre-conversion gas contact more evenly, so that the combustion is more stable.
[0053] Further, the natural gas to methanol system is also provided with a steam drum 5, which is arranged after the cold medium outlet of the second heat exchanger 3 and before the branch pipeline 51. The cold medium outlet of the second heat exchanger 3 is connected to the inlet end of the steam drum 5, and the outlet end of the steam drum 5 is connected to the raw material gas inlet of the conversion tower 1 and the inlet end of the combustion section 12. That is, the preheated desalted water vapor after the second heat exchanger 3 enters the steam drum 5, and then is distributed and discharged to the heat conversion section 11 and the combustion section 12 to participate in the pre-conversion reaction and the combustion reaction. The steam drum 5 provides stable steam flow and facilitates flow control.
[0054] A burner 121 is arranged at the inlet end of the combustion section 12, and the oxygen source pipeline 6 and the branch pipeline 51 of the cold medium outlet of the second heat exchanger 3 are both connected to the burner 121. At the same time, the pre-conversion gas pipeline 14 is also connected to the burner 121, so that the pre-conversion gas, oxygen and desalted water vapor are fully mixed and burned in the burner 121.
[0055] In one embodiment, as shown in Fig. 1 and Fig. 2 The conversion tower 1 is vertically arranged, and the heat conversion section 11, the second conversion section 13 and the combustion section 12 are arranged in sequence from top to bottom.
[0056] In another embodiment, as shown in Fig. 3 The conversion tower 1 is vertically arranged, and the combustion section 12, the second conversion section 13 and the heat conversion section 11 are arranged in sequence from top to bottom.
[0057] Further, in the above two embodiments, one end of the pre-conversion passage 111 in the heat conversion section 11 is in communication with the raw material gas inlet, and the other end is in communication with the pre-conversion gas outlet; one end of the heat exchange passage 112 in the heat conversion section 11 is connected to the outlet end of the second conversion section 13, and the other end is in communication with the synthesis gas outlet; the pre-conversion gas outlet is connected to the burner 121 at the inlet end of the combustion section 12 through the pre-conversion gas pipeline 14.
[0058] The second conversion section 13 and the pre-conversion passage 111 are both filled with a catalyst layer.
[0059] The raw gas (natural gas and desalted water vapor) is subjected to heat exchange pre-catalytic conversion reaction in the pre-conversion passage 111 of the heat exchange conversion section 11, and is discharged to the burner 121 of the combustion section 12 after pre-conversion through the pre-conversion gas pipeline 14 to be combusted, and enters the secondary conversion section 13 to generate high-temperature synthesis gas by high-temperature catalytic conversion, which is discharged after heat exchange in the heat exchange conversion section 11.
[0060] The heat exchange conversion section 11, the secondary conversion section 13 and the combustion section 12 of the conversion tower 1 are sequentially arranged from top to bottom, and can be operated in a downstream flow direction by means of the flow direction of the high-temperature gaseous fluid, so as to realize low-pressure and rapid conversion and discharge, and the system has a high conversion production speed.
[0061] The combustion section 12, the secondary conversion section 13 and the heat exchange conversion section 11 of the conversion tower 1 are sequentially arranged from top to bottom, so that the high-temperature gaseous fluid flows in a reverse direction, and the combustion, catalytic conversion reaction and heat exchange can be carried out more fully under a higher pressure, so as to realize deep conversion and improve the conversion efficiency of the system.
[0062] Further, the natural gas to methanol system further comprises a cooler 7, a gas-liquid separator 71, a compressor 72 and a methanol synthesis device 73 which are sequentially arranged through pipelines; and the inlet end of the cooler 7 is connected with the heat medium outlet end of the second heat exchanger 3. The synthesis gas cooled by the second heat exchanger 3 is cooled to normal temperature by the cooler 7, and then is subjected to gas-liquid separation by the gas-liquid separator 72 in sequence, the separated gas is pressurized to a required pressure (such as 4-15 MPa) by the compressor 72, and then enters the methanol synthesis device 73 as fresh gas to synthesize and prepare methanol.
[0063] Working process: natural gas enters the first heat exchanger 2, is preheated to a certain temperature by the synthesis gas, and then enters the natural gas purifier 4 to remove the substances harmful to the conversion catalyst in the natural gas; then is mixed with the water vapor evaporated by the second heat exchanger 3, and enters the heat exchange conversion section 11 of the conversion tower 1 through the raw gas inlet after mixing, to carry out pre-conversion reaction, about 20% of CH4 in the natural gas is converted into H2, CO and CO2 in the heat exchange conversion section 11, and the heat of the heat exchange conversion section 11 is provided by the synthesis gas discharged from the secondary conversion section 13; the pre-conversion gas enters the combustion section 12, and encounters the mixture of oxygen and water vapor to carry out combustion reaction; the high-temperature gas after combustion enters the secondary conversion section 13 to carry out high-temperature deep catalytic conversion, and the content of methane in the converted synthesis gas is reduced to below 0.5%; the synthesis gas is discharged from the conversion tower 1 after heat exchange and temperature reduction in the heat exchange conversion section 11, and is subjected to heat exchange and temperature reduction in sequence by the first heat exchanger 2, the second heat exchanger 3 and the like, and finally is subjected to cooling, gas-liquid separation, gas pressurization and methanol synthesis in sequence by the cooler 7, the gas-liquid separator 71, the compressor 72 and the methanol synthesis device 73.
Claims
1. A system for the production of methanol from natural gas, characterized in that, The system comprises: a conversion tower; a first heat exchanger, a hot medium inlet of which is connected with a syngas outlet of the conversion tower, a cold medium inlet is connected with a natural gas source, and a cold medium outlet is connected with a raw material gas inlet of the conversion tower; a second heat exchanger, a hot medium inlet of which is connected with a hot medium outlet of the first heat exchanger, a cold medium inlet is connected with a desalted water source, and a cold medium outlet is connected with a raw material gas inlet of the conversion tower; wherein the conversion tower comprises a heat exchange conversion section, a combustion section and a second conversion section, the heat exchange conversion section is connected with an inlet end of the combustion section and an outlet end of the second conversion section, and the raw material gas inlet and the syngas outlet are both arranged in the heat exchange conversion section.
2. The system for the production of methanol from natural gas according to claim 1, characterized in that, A natural gas purifier is further arranged, an inlet of the natural gas purifier is connected with a cold medium outlet of the first heat exchanger, and an outlet of the natural gas purifier is connected with a raw material gas inlet of the conversion tower.
3. The system for the production of methanol from natural gas according to claim 1, characterized in that, An oxygen source pipeline is further arranged, which is connected with the inlet end of the combustion section.
4. The system for the production of methanol from natural gas according to claim 3, characterized in that, A branch pipeline is further arranged, which is connected with a cold medium outlet of the second heat exchanger and the inlet end of the combustion section.
5. The system for the production of methanol from natural gas according to claim 4, characterized in that, A steam drum is further arranged, an inlet end of the steam drum is connected with a cold medium outlet of the second heat exchanger, and an outlet end of the steam drum is connected with a raw material gas inlet of the conversion tower and an inlet end of the combustion section.
6. The system for the production of methanol from natural gas according to claim 4 or 5, characterized in that, The inlet end of the combustion section is provided with a burner, and the oxygen source pipeline and the branch pipeline of the cold medium outlet of the second heat exchanger are both connected with the burner.
7. The system for producing methanol from natural gas according to claim 1, wherein: the heat exchange conversion section, the second conversion section and the combustion section of the conversion tower are arranged in sequence from top to bottom; or, the combustion section, the second conversion section and the heat exchange conversion section of the conversion tower are arranged in sequence from top to bottom.
8. The system for producing methanol from natural gas according to claim 1 or 7, characterized in that, A pre-conversion channel of the heat exchange conversion section is in communication with a raw material gas inlet and a pre-conversion gas outlet, a heat exchange channel of the heat exchange conversion section is in communication with an outlet end of the second conversion section and a syngas outlet, and the pre-conversion gas outlet is connected with an inlet end of the combustion section through a pre-conversion gas pipeline.
9. The system for the production of methanol from natural gas according to claim 8, characterized in that, The second conversion section and the pre-conversion channel are both filled with a catalyst layer.
10. The system for the production of methanol from natural gas according to claim 1, characterized in that, A cooler, a gas-liquid separator, a compressor and a methanol synthesis device are further arranged in sequence, and an inlet end of the cooler is connected with a hot medium outlet end of the second heat exchanger.