CN109180430B - Methanol synthesis process - Google Patents
Methanol synthesis process Download PDFInfo
- Publication number
- CN109180430B CN109180430B CN201811162812.0A CN201811162812A CN109180430B CN 109180430 B CN109180430 B CN 109180430B CN 201811162812 A CN201811162812 A CN 201811162812A CN 109180430 B CN109180430 B CN 109180430B
- Authority
- CN
- China
- Prior art keywords
- heat exchange
- water
- exchange tube
- steam
- mixed gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
- C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
- C07C29/152—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by the reactor used
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
- C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
- C07C29/153—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by the catalyst used
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a methanol synthesis process, which comprises a water-cooled reactor, wherein a plurality of heat exchange tubes are arranged in the water-cooled reactor, the inlet of each heat exchange tube is connected with the boiler water outlet of a steam drum through a water inlet tube, and the outlet of each heat exchange tube is connected with the steam inlet of the steam drum through a steam recovery pipeline; the method is characterized in that: the heat exchange tubes in each water-cooled reactor comprise a first heat exchange tube group consisting of a plurality of first heat exchange tubes and a second heat exchange tube group consisting of a plurality of second heat exchange tubes; the heat exchange area of each second heat exchange tube accounts for 15-40% of the total heat exchange area; the mixed gas sequentially enters a gas-cooled reactor and a mixed gas preheater, is heated to 230-240 ℃, is divided into two parts, and respectively enters a first water-cooled reactor and a second water-cooled reactor; two groups of heat exchange tubes work simultaneously in the early stage of the operation of the device, and the second heat exchange tube set is closed and only the first heat exchange tube set works in the later stage of the operation of the device.
Description
Technical Field
The invention relates to a methanol synthesis process.
Background
Methanol synthesis is a reversible exothermic reaction process. For the copper-based methanol synthesis catalyst, the reaction temperature needs to be maintained between 220 ℃ and 280 ℃, the catalyst does not have activity when the temperature is too low, and the service life and the product quality of the catalyst are influenced when the temperature is too high. In order to make the methanol synthesis reaction proceed in a suitable temperature range, heat exchange tubes are usually embedded in the catalyst reaction bed layer, the reaction heat released during the methanol synthesis is removed by the steam generated by the gasification of boiler water in the heat exchange tubes, this type of reactor is called isothermal methanol synthesis reactor, and the methanol synthesis process provided with the isothermal methanol synthesis reactor is called isothermal methanol synthesis process.
Based on the consideration of prolonging the service life of the methanol synthesis catalyst, the reaction temperature of the catalyst is generally controlled between 240 ℃ and 260 ℃ in the initial stage of use, and the reaction temperature of the catalyst is generally controlled between 260 ℃ and 280 ℃ in the later stage of use. When the device is stably operated, the reaction heat removed by the steam generated by the boiler water in the heat exchange tubes is constant, but the reaction temperature slowly rises from 240 ℃ to 280 ℃ along with the aging of the catalyst, the temperature of the boiler water in the corresponding heat exchange tubes slowly rises from 225 ℃ to 270 ℃, and the steam pressure generated by the boiler water gradually rises from 2.7MPaG to 5.4 MPaG. It can be seen that the temperature interval span of the isothermal methanol synthesis process is large, and the pressure fluctuation of the produced steam is also large.
Along with the large-scale and multi-series methanol synthesis device, the amount of rich steam is more and more, but the existing isothermal methanol synthesis process can not solve the problems of steam pressure fluctuation, increase of investment of related equipment and pipeline engineering and the like all the time, and the method is mainly embodied as follows:
considering from the design pressure, because the pressure of the steam generated in the heat exchange tube fluctuates between 2.7MPaG and 5.4MPaG, the equipment and the pipeline related to the heat exchange tube need to consider higher design pressure, otherwise, the steam pressure requirement of 5.4MPaG at the later stage of the catalyst cannot be met, and the increase of the wall thickness of the equipment and the pipeline increases the engineering investment;
in view of rich steam, although the high-quality steam of 5.4MPaG can be rich in the later stage of the catalyst, the balance of the steam pipe network of the whole plant is determined by the steam of 2.7MPaG at the initial stage of the catalyst, and only the high-quality steam of 5.4MPaG can be decompressed and degraded for use in engineering design, so that pipeline valves and automatic control instrument elements related to decompression are required to be added, and certain impact is also caused on the steam pipe network of the whole plant.
In short, the pipelines and equipment of a boiler water system in a methanol synthesis reactor need to be designed according to the harsh temperature and pressure, and meanwhile, the medium-pressure steam produced in the later stage of the catalyst is degraded for use, so that the investment and the balance of a whole plant steam pipe network are not economical and reasonable.
Chinese patent publication No. CN 107162872A discloses a low pressure methanol synthesis process in which heat exchange tubes are embedded in a reaction bed of a methanol synthesis reactor, methanol synthesis is carried out in a catalyst bed, and the released reaction heat is removed by boiler water in the heat exchange tubes. However, the steam pressure of the rich product in the later period of the catalyst is increased, and the related equipment and pipelines have to be designed according to the steam pressure and the temperature in the later period, so that the engineering investment is increased; meanwhile, when the balance design of the steam pipe network of the whole plant is carried out by the process system, the process system can only be designed according to the lower steam pressure and steam quality at the initial stage of the catalyst, but certain impact is caused on the steam pipe network of the whole plant at the later stage of the catalyst.
Disclosure of Invention
The invention aims to solve the technical problem of providing a methanol synthesis process which has the advantages of quick and adjustable heat removal capacity, accurate and controllable bed layer temperature and capability of maintaining constant yield in the whole active period of a catalyst without increasing the wall thickness of equipment aiming at the current situation of the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows: the methanol synthesis process comprises a water-cooled reactor, wherein a plurality of heat exchange tubes are arranged in the water-cooled reactor, the inlet of each heat exchange tube is connected with the boiler water outlet of a steam drum through a water inlet tube, and the outlet of each heat exchange tube is connected with the steam inlet of the steam drum through a steam recovery pipeline; the method is characterized in that:
the number of the water-cooled reactors is two, and the two water-cooled reactors are mutually connected in parallel;
the heat exchange tubes in each water-cooled reactor comprise a first heat exchange tube group consisting of a plurality of first heat exchange tubes and a second heat exchange tube group consisting of a plurality of second heat exchange tubes; the heat exchange area of each second heat exchange tube accounts for 15-40% of the total heat exchange area;
the sum of the heat exchange areas of the first heat exchange tubes in the catalyst bed layer is the heat exchange area of the first heat exchange tubes; the sum of the heat exchange areas of the second heat exchange tubes in the catalyst bed layer is the heat exchange area of the second heat exchange tubes; the total heat exchange area is the sum of the heat exchange area of the first heat exchange tube and the heat exchange area of the second heat exchange tube;
the heat exchange area of each heat exchange tube is 2 pi rL, pi is the circumference ratio, r is the radius of the heat exchange tube, and L is the length of the heat exchange tube in the catalyst bed layer.
Correspondingly, two water inlet pipes are arranged;
the inlet of each first heat exchange tube is connected with a first water inlet tube, and the inlet of each second heat exchange tube is connected with a second water inlet tube; a valve is arranged on the second water inlet pipe;
from upstream at 130-140 deg.C and 5-10 MPaG, H2Taking mixed gas with the mol ratio of 5-6/CO as a heat taking medium, entering a gas cooling reactor to be preheated to 195-215 ℃, entering a mixed gas preheater to be heated to 230-240 ℃, dividing into two parts, and respectively entering a first water cooling reactor and a second water cooling reactor;
the mixed gas is subjected to primary methanol synthesis reaction in catalyst beds of a first water-cooled reactor and a second water-cooled reactor; boiler water with the temperature of 225-245 ℃ and the pressure of 3.7-4.2 MPaG in the steam pocket simultaneously enters the first heat exchange tube group and the second heat exchange tube group to take reaction heat of the catalyst bed layer away to generate medium-pressure saturated steam with the temperature of 3.7-4.2 MPaG and the temperature of 247-255 ℃, the medium-pressure saturated steam returns to the steam pocket, and after gas-liquid separation, the medium-pressure saturated steam is discharged out of the steam pocket and sent to a steam pipe network;
obtaining primary reaction gas with the temperature of 250-260 ℃ and the methanol content of 11-14 mol% at the outlet of the water-cooled reactor, enabling the primary reaction gas to enter a mixed gas preheater after parallel flow, preheating the mixed gas, reducing the temperature to 210-230 ℃, and enabling the mixed gas to enter a gas-cooled reactor to perform secondary methanol synthesis reaction; the secondary synthesis gas with the temperature of 210-225 ℃ obtained at the outlet of the gas-cooled reactor enters a downstream system;
in the running process of the device, the content of methanol in the primary reaction gas is monitored on line, and when the content of the methanol is less than or equal to 10mol, a control valve on the second water inlet pipe is gradually closed at a descending speed of 10% volume flow per hour; when the temperature of the catalyst bed layer is increased to 270-290 ℃, a control valve on the second water inlet pipe is closed, the second heat exchange pipe set does not work, and only the first heat exchange pipe set works;
at the moment, the mixed gas entering the mixed gas preheater is subjected to heat exchange to 255-275 ℃ and enters a water-cooled reactor, the temperature of the primary reaction gas is 270-290 ℃, and the methanol content is 11-14 mol%; still produce 3.7-4.0 MPaG of medium pressure saturated steam.
Preferably, each heat exchange tube is spirally wound in the catalyst bed layer by taking the mixed gas distribution tube as a mandrel; each heat exchange tube is spirally wound to form a plurality of heat exchange tube layers, and gaps are formed between the adjacent heat exchange tube layers; the first heat exchange tube and the second heat exchange tube are arranged on each layer of heat exchange tube layer, and the first heat exchange tube is arranged between every two adjacent second heat exchange tubes. The structure is uniform in heat extraction.
Further, the heat exchange tubes on the adjacent heat exchange tube layers are opposite in rotation direction.
Preferably, 2-5 first heat exchange tubes are arranged between the two second heat exchange tubes; the pipe diameters of the first heat exchange pipe and the second heat exchange pipe are equal.
Further, each heat exchange tube layer is fixed on many spinal branchs vaulting pole, each the bracing piece is vertical interval to be set up.
Preferably, each heat exchange tube is fixed on the support plate through a hoop.
Preferably, each heat exchange tube is connected with a steam recovery pipeline through a steam collection pipe; and an expansion joint is arranged on the steam recovery pipeline.
The structure of other parts of the water-cooled reactor in each scheme can adopt the prior art as required, preferably, the water-cooled reactor is a radial reactor, preferably, the water-cooled reactor comprises a furnace body and a catalyst frame arranged in the furnace body, the middle part of the catalyst frame is provided with a mixed gas distribution pipe, and the mixed gas distribution pipe is connected with a mixed gas inlet on the furnace body; a plurality of outlets of the mixed gas distribution pipe are arranged on the side wall of the mixed gas distribution pipe at intervals; the side wall of the catalyst frame is provided with an air outlet through which synthetic gas passes, and the air outlet is communicated with a synthetic gas outlet on the furnace body; and a plurality of heat exchange tubes are arranged in the catalyst bed layer between the catalyst frame and the mixed gas distribution tube, the inlet of each heat exchange tube is connected with a water inlet pipeline, and the outlet of each heat exchange tube is connected with a steam pipeline.
For convenient inspection, maintenance, the mist distribution pipe can be dismantled in proper order by the multistage barrel and connect and form, be equipped with a plurality of foot ladders along the direction of height interval in proper order on the inside wall of barrel.
Further, the installation position of the steam drum is higher than the first water-cooled reactor and the second water-cooled reactor. According to the scheme, boiler water in the steam drum can naturally enter the two water-cooled reactors under the self gravity, natural circulation is realized by utilizing density difference, no circulating equipment is additionally arranged, the energy-saving and consumption-reducing effects are good, and the equipment investment is saved.
Compared with the prior art, the invention has the advantages that: two groups of heat exchange tube sets are arranged in the two water-cooled reactors; in the initial operation stage of the device, the catalyst activity is high, the two groups of heat exchange tubes work simultaneously, the removed reaction heat is large, the catalyst bed layer is maintained at the set temperature for methanol synthesis reaction, and the yield is constant at the set value; in the later stage of the operation of the device, the activity of the catalyst is reduced, and the activity temperature of the catalyst is increased; the opening of one water inlet valve is adjusted until one group of heat exchange tubes in the reactor is closed, the heat removal quantity of the catalyst bed layer is reduced, the temperature of the catalyst bed layer is raised to the active temperature of the catalyst, the methanol synthesis reaction is normally carried out, the yield is still maintained at a designed value, parameters such as boiler water, steam pressure and the like in the steam drum and the steam drum are maintained unchanged, the steam pressure out of the steam drum is unchanged, parameters of matched pipelines and equipment do not need to be changed, and the impact on a steam pipe network is small; greatly saving the equipment investment.
Drawings
FIG. 1 is a schematic process flow diagram of an embodiment of the present invention;
FIG. 2 is a longitudinal cross-sectional view of an embodiment of the present invention;
FIG. 3 is an enlarged view of a portion A of FIG. 2;
FIG. 4 is a fixing structure of the heat exchange tube layer in the embodiment of the invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
As shown in fig. 1 to 4, two water-cooled reactors in this embodiment include a first water-cooled reactor a4 and a second water-cooled reactor a6, which are arranged in parallel, and the two water-cooled reactors have the same structure. Both comprise:
the furnace body 1 is of a conventional structure and comprises an upper seal head 11, a lower seal head 12 and a cylinder body 13 connected between the upper seal head 11 and the lower seal head 12.
The catalyst frame 2 is disposed in the cylinder 13. The catalyst frame 2 can be any one of the prior art according to the requirement, the embodiment is a radial reactor, and the mixed gas enters the catalyst frame of the catalyst frame 2 from the mixed gas distribution pipe 3; a plurality of synthesis gas outlet holes are formed in the side wall of the catalyst frame; after the methanol synthesis catalytic reaction, the mixed gas is discharged from each synthesis gas outlet hole on the catalyst frame, enters a channel between the catalyst frame and the furnace body, enters a synthesis gas outlet through the channel, and finally is sent out of the furnace body 1 through a synthesis gas pipeline 33 connected with the synthesis gas outlet.
The mixed gas distribution pipe 3 is used for distributing mixed gas, is arranged in the middle position in the cavity of the catalyst frame 2, and is formed by sequentially and detachably connecting a plurality of sections of cylinder bodies 31, and in the embodiment, the cylinder bodies 31 are connected through flanges 34; a plurality of footsteps 32 are sequentially arranged on the inner side wall of the cylinder 31 at intervals along the axial direction. The end cover is detachably connected to the lower port of the mixed gas distribution pipe 3, the upper port of the mixed gas distribution pipe 3 is connected with a mixed gas inlet at the top of the furnace body, and the mixed gas inlet is connected with a mixed gas pipeline 35; the lower port of the mixed gas distribution pipe 3 is closed; a plurality of air outlets are arranged on the side wall of the mixed gas distribution pipe 3 at intervals, and the mixed gas entering the mixed gas distribution pipe 3 enters the catalyst bed layer through each air outlet.
The space between the mixed gas distribution pipe 3 and the catalyst frame is filled with a catalyst to form a catalyst bed.
The heat exchange tubes include a first heat exchange tube group composed of a plurality of first heat exchange tubes 41 and a second heat exchange tube group composed of a plurality of second heat exchange tubes 42. For the sake of distinction, in fig. 3, each second heat exchange tube 42 is represented by a solid circle and a solid filled pattern, and each first heat exchange tube 41 is represented by a hollow circle.
The heat exchange tubes are sequentially coiled outside the mixed gas distribution tube 3 along the mixed gas distribution tube 3 to form a plurality of layers, and the spiral directions of the heat exchange tubes between adjacent layers are opposite. Each layer of heat exchange tubes comprises a first heat exchange tube 41 and a second heat exchange tube 42, and the first heat exchange tube 41 and the second heat exchange tube 42 are uniformly arranged at intervals in a staggered manner. Set up 1 second heat exchange tube 42 behind 2~5 first heat exchange tubes 41 promptly, set up 1 second heat exchange tube 42 behind this embodiment for setting up 2 first heat exchange tubes.
Each heat exchange tube layer is fixed on a plurality of support rods 6, each support rod 6 is vertically arranged and arranged at intervals, and adjacent support rods are not on the same radial radiation line. In this embodiment, each heat exchange tube is fixed to the support plate by a hoop 61.
The diameters of the first heat exchange tube 41 and the second heat exchange tube 42 can be flexibly adjusted according to the scale of the device and the load change, and the diameters of the heat exchange tubes are the same in the implementation.
The sum of the heat exchange areas of the second heat exchange tubes 42 is 15-40% of the total heat exchange area, which is 33% in this embodiment.
And the water inlet pipeline is used for communicating the steam pocket A5 with each heat exchange pipe and is respectively connected with the first water inlet pipe 51 and the second water inlet pipe 52. The outlet of the first water inlet pipe 51 is communicated with a first pipe box 55, and the first pipe box 55 is connected with the inlet of each first heat exchange pipe 41; the outlet of the second water inlet pipe 52 is communicated with a second pipe box 54, and the second pipe box 54 is connected with the inlet of each second heat exchange pipe 42. A valve 56 is arranged on the second water inlet pipe 52.
The first and second header tanks 55 and 54 may have a ring pipe structure, as shown in fig. 2 of the present embodiment; the two tube boxes can also be box structures which are arranged in an up-and-down overlapping mode, and the two tube boxes can also be in a tube plate mode.
The steam pipeline comprises a steam connecting pipe 59 and a steam collecting pipe 58, wherein the steam connecting pipe 59 is connected with the steam drum, and the outlet of the steam collecting pipe 58 is connected with the steam connecting pipe 59; the outlet of each first heat exchange tube and the outlet of each second heat exchange tube are communicated with the inlet of each steam collecting tube 58. The steam collection pipe 58 may be of a loop configuration, a box configuration, or other configuration.
And an expansion joint 59a provided on the steam connection pipe 59 for absorbing thermal stress.
Due to the special arrangement of the first heat exchange tube and the second heat exchange tube, the first heat exchange tube can uniformly remove heat from the catalyst bed even if the second heat exchange tube is closed.
The temperature of the upstream gas is 135 +/-5 ℃ and the pressure is 5-10 MPaG and H in the early stage of the operation of the device2The mixed gas A1 with the mol ratio of 5.5/CO enters a gas-cooled reactor A2 to be preheated to 205 +/-5 ℃, enters a mixed gas preheater A3 to be heated to 235 +/-5 ℃, is divided into two parts and simultaneously enters a first water-cooled reactor A4 and a second water-cooled reactor A6 respectively, the mixed gas generates methanol synthesis reaction in catalyst bed layers of the first water-cooled reactor A4 and the second water-cooled reactor A6, and the activity temperature of the catalyst, namely the reaction temperature of the water-cooled reactor is 250-255 ℃.
Boiler water with the temperature of 235 ℃ and the pressure of 3.7-4.0 MPaG in the steam pocket A5 simultaneously enters a first heat exchange tube group and a second heat exchange tube group of two water-cooled reactors, the reaction heat of a catalyst bed layer is taken away, medium-pressure saturated steam of 3.7-4.0 MPaG is generated and returns to the steam pocket A5 from a steam connecting pipe 59, and after gas-liquid separation, the medium-pressure saturated steam is discharged from the steam pocket A5 and sent to a steam pipe network; during the operation of the device, medium-pressure boiler water with the temperature of 225 ℃ and the pressure of 3.9 MPaG-4.2 MPaG is supplemented into the steam drum A5.
The temperature of the reaction gas at the outlet of the first water-cooled reactor A4 and the second water-cooled reactor A6 is 250-260 ℃, the reaction gas and the reaction gas flow in parallel and then enter a mixed gas preheater A3 to exchange heat with the mixed gas to 220 +/-5 ℃ and enter a gas-cooled reactor A2 to carry out methanol synthesis reaction. The heat of reaction in the gas-cooled reactor A2 was used to preheat the mixed gas A1. The temperature of the reaction gas exiting the gas-cooled reactor A2 was 220 ℃. + -. 5 ℃ and entered the downstream system. The molar content of methanol in the reaction gas at the outlets of the two water-cooled reactors A4 and A6 is 12-13%.
In the running process of the device, monitoring the methanol content of the reaction gas at the outlets of the two water-cooled reactors on line, and when the methanol content is less than or equal to 10 mol%; or when the catalyst has reached a half-life; in this case, the catalyst activity decreases, and the catalyst activity temperature needs to be increased. Gradually closing the control valve 56 on the second water inlet pipe 52 at a decreasing speed of 10% volume flow per hour, closing the control valves on the second water inlet pipes of the two water-cooled reactors when the temperature of the catalyst bed is gradually increased from 255 ℃ to 280 ℃, stopping the second heat exchange pipe group and only working the first heat exchange pipe group; at the moment, the CO conversion rate of primary reaction gas at the outlets of the two water-cooled reactors is unchanged, the same as the earlier stage of the operation of the device is realized, and the methanol content of the primary reaction gas is recovered to 12-13 mol% at the temperature of 280 ℃; still produce 3.7-4.0 MPaG of medium pressure saturated steam.
And the cocurrent primary reaction gas enters a mixed gas preheater A3 to preheat the mixed gas, and the mixed gas is heated to 265 ℃ and enters two water-cooled reactors.
After the second heat exchange tube group is closed, compared with the two heat exchange tube groups which work simultaneously, the heat exchange area is reduced by 33 percent, and the temperature of a catalyst bed layer is improved to meet the higher activity temperature of the catalyst by reducing the heat exchange area.
After the second group of heat exchange tubes are closed, boiler water in the steam drum A5 only enters the first group of heat exchange tubes, the boiler water in the first group of heat exchange tubes exchanges heat with reaction heat of the catalyst bed layer, and medium-pressure saturated steam with the pressure of 3.7-4.0 MPaG and the temperature of 247-252 ℃ is generated and returns to the steam drum A5.
In the whole process of the device operation, the steam pressure does not need to be changed, the equipment requirement on the steam pipe network is reduced, and the stable operation of the steam pipe network and the device is ensured; meanwhile, the constant yield of the reaction gas is ensured, and the device runs stably.
Comparative example
Take a methanol synthesis device of 100 ten thousand tons/year as an example (effective gas (H)2+ CO) is approximately 266000N/m3/h，H2[ CO ] 2.3 (molar ratio)). All the operating conditions were the same as in this example, except that the water-cooled reactor was a common water-cooled reactor, only one set of heat exchange tubes was provided, and all the heat exchange tubes were operated simultaneously during the entire operation of the apparatus, and table 1 lists the drum systems and the corresponding examplesAnd comparing the main parameters of the pipeline investment.
TABLE 1
As can be seen from table 1, for the conventional methanol synthesis apparatus, the methanol synthesis technology of this embodiment significantly reduces the pressure fluctuation of the medium pressure steam by-product of the water-cooled reactor, the design pressure of the steam drum, the design pressure of the boiler water pipe network and the medium pressure steam pipe network, and the design pressure of the water-cooled reactor, so that the design thickness of the equipment is reduced, the equipment investment is significantly reduced, the direct investment of the equipment and the pipeline can be reduced by about 250 ten thousand yuan, and simultaneously, compared with the steam pipe network pressure fluctuation in a large range of the comparative example, the steam pipe network pressure produced by the present invention is more stable, which is beneficial to the operation of the apparatus and the long-term stable operation of the steam pipe network and the apparatus.
Claims (9)
1. A methanol synthesis process comprises a water-cooled reactor, wherein a plurality of heat exchange tubes are arranged in the water-cooled reactor, the inlet of each heat exchange tube is connected with the boiler water outlet of a steam drum through a water inlet tube, and the outlet of each heat exchange tube is connected with the steam inlet of the steam drum through a steam recovery pipeline; the method is characterized in that:
the number of the water-cooled reactors is two, and the two water-cooled reactors are mutually connected in parallel;
the heat exchange tubes in each water-cooled reactor comprise a first heat exchange tube group consisting of a plurality of first heat exchange tubes and a second heat exchange tube group consisting of a plurality of second heat exchange tubes; the heat exchange area of each second heat exchange tube accounts for 15-40% of the total heat exchange area;
correspondingly, two water inlet pipes are arranged;
the inlet of each first heat exchange tube is connected with a first water inlet tube, and the inlet of each second heat exchange tube is connected with a second water inlet tube; a valve is arranged on the second water inlet pipe;
from upstream at 130-140 deg.C, 5-10 MPaG, H2Taking mixed gas with a mol ratio of 5-6/CO as a heat taking medium, entering a gas cooling reactor to be preheated to 195-215 ℃, and entering the mixed gasHeating the mixture to 230-240 ℃ by a heater, dividing the mixture into two parts, and respectively entering a first water-cooled reactor and a second water-cooled reactor;
the mixed gas is subjected to primary methanol synthesis reaction in catalyst beds of a first water-cooled reactor and a second water-cooled reactor; boiler water with the temperature of 225-245 ℃ and the pressure of 3.7-4.2 MPaG in the steam pocket simultaneously enters the first heat exchange tube group and the second heat exchange tube group to take reaction heat of the catalyst bed layer away, medium-pressure saturated steam with the temperature of 3.7-4.2 MPaG and the temperature of 247-255 ℃ is generated and returns to the steam pocket, and after gas-liquid separation, the medium-pressure saturated steam is discharged from the steam pocket and sent to a steam pipe network;
obtaining primary reaction gas with the temperature of 250-260 ℃ and the methanol content of 11-14 mol% at the outlet of the water-cooled reactor, enabling the primary reaction gas to enter a mixed gas preheater after parallel flow, preheating the mixed gas, reducing the temperature to 210-230 ℃, and enabling the mixed gas to enter a gas-cooled reactor to perform secondary methanol synthesis reaction; the secondary synthesis gas with the temperature of 210-225 ℃ obtained at the outlet of the gas-cooled reactor enters a downstream system;
in the operation process of the device, monitoring the methanol content in the primary reaction gas on line, and gradually closing a control valve on a second water inlet pipe at a decreasing speed of 8-15% volume flow/hour when the methanol content is less than or equal to 10 mol; when the temperature of the catalyst bed layer is increased to 270-290 ℃, a control valve on the second water inlet pipe is closed, the second heat exchange pipe set does not work, and only the first heat exchange pipe set works;
at the moment, the mixed gas entering the mixed gas preheater is subjected to heat exchange to 255-275 ℃ and enters a water-cooled reactor, the temperature of the primary reaction gas is 270-290 ℃, and the methanol content is 11-14 mol%; still enriching the medium-pressure saturated steam of 3.7-4.2 MPaG;
each heat exchange tube is spirally wound in the catalyst bed layer by taking the mixed gas distribution tube as a mandrel; each heat exchange tube is spirally wound to form a plurality of heat exchange tube layers, and gaps are formed between the adjacent heat exchange tube layers; the first heat exchange tube and the second heat exchange tube are arranged on each layer of heat exchange tube layer, and the first heat exchange tube is arranged between every two adjacent second heat exchange tubes.
2. The methanol synthesis process of claim 1, wherein the heat exchange tubes on adjacent heat exchange tube layers have opposite rotation directions.
3. The methanol synthesis process according to claim 2, wherein 2-5 first heat exchange tubes are arranged between the two second heat exchange tubes; the pipe diameters of the first heat exchange pipe and the second heat exchange pipe are equal.
4. The methanol synthesis process of claim 3, wherein each heat exchange tube layer is fixed on a plurality of support rods, and the support rods are vertically spaced.
5. The methanol synthesis process of claim 4, wherein each heat exchange tube is fixed to the support rod by a hoop.
6. The methanol synthesis process according to any one of claims 1 to 5, wherein each of the heat exchange tubes is connected to a vapor recovery conduit via a vapor collection tube; and an expansion joint is arranged on the steam recovery pipeline.
7. The methanol synthesis process according to claim 6, wherein the water-cooled reactor comprises a furnace body and a catalyst frame arranged in the furnace body, a mixed gas distribution pipe is arranged in the middle of the catalyst frame, and the mixed gas distribution pipe is connected with a mixed gas inlet on the furnace body; a plurality of outlets of the mixed gas distribution pipe are arranged on the side wall of the mixed gas distribution pipe at intervals; the side wall of the catalyst frame is provided with an air outlet through which synthetic gas passes, and the air outlet is communicated with a synthetic gas outlet on the furnace body; and a plurality of heat exchange tubes are arranged in the catalyst bed layer between the catalyst frame and the mixed gas distribution tube, the inlet of each heat exchange tube is connected with a water inlet pipeline, and the outlet of each heat exchange tube is connected with a steam pipeline.
8. The methanol synthesis process according to claim 7, wherein the mixed gas distribution pipe is formed by sequentially detachably connecting a plurality of sections of cylinders, and a plurality of footsteps are sequentially arranged on the inner side wall of each cylinder at intervals in the height direction.
9. The methanol synthesis process of claim 8, wherein the steam drum is installed at a position higher than the first and second water-cooled reactors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811162812.0A CN109180430B (en) | 2018-09-30 | 2018-09-30 | Methanol synthesis process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811162812.0A CN109180430B (en) | 2018-09-30 | 2018-09-30 | Methanol synthesis process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109180430A CN109180430A (en) | 2019-01-11 |
| CN109180430B true CN109180430B (en) | 2022-01-18 |
Family
ID=64946634
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811162812.0A Active CN109180430B (en) | 2018-09-30 | 2018-09-30 | Methanol synthesis process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109180430B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102698659A (en) * | 2012-03-28 | 2012-10-03 | 中国石油化工股份有限公司 | Methanol synthesis reactor structure |
| CN105642197A (en) * | 2014-09-24 | 2016-06-08 | 楼韧 | Large-sized reactor, and device and process thereof |
| CN107382665A (en) * | 2017-07-13 | 2017-11-24 | 南京国昌化工科技有限公司 | The technique and device of a kind of methanol-fueled CLC |
-
2018
- 2018-09-30 CN CN201811162812.0A patent/CN109180430B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102698659A (en) * | 2012-03-28 | 2012-10-03 | 中国石油化工股份有限公司 | Methanol synthesis reactor structure |
| CN105642197A (en) * | 2014-09-24 | 2016-06-08 | 楼韧 | Large-sized reactor, and device and process thereof |
| CN107382665A (en) * | 2017-07-13 | 2017-11-24 | 南京国昌化工科技有限公司 | The technique and device of a kind of methanol-fueled CLC |
Non-Patent Citations (1)
| Title |
|---|
| "双塔并联式甲醇合成工艺运行总结";孙西英等;《化工设计通讯》;20130630;第39卷(第3期);第71页第1-2段 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109180430A (en) | 2019-01-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109319733B (en) | CO conversion process matched with methanol synthesis | |
| CN109052319B (en) | High CO conversion process matched with methanol synthesis | |
| CN109264668B (en) | CO conversion process matched with methanol synthesis | |
| CN109081346B (en) | High CO isothermal conversion process matched with methanol synthesis | |
| CN102888252A (en) | Saturation tower/isothermal furnace series/heat isolation furnace CO transformation technology | |
| CN102887481B (en) | Low water-gas ratio pre-conversion constant-temperature CO conversion technology | |
| CN109319734B (en) | CO conversion process matched with methanol synthesis | |
| CN102886230A (en) | CO (carbon monoxide) conversion process adopting tandem isothermal furnaces of saturation tower | |
| CN109111342B (en) | Water-cooling methanol synthesis process | |
| CN110790223B (en) | Transformation hydrogen production method matched with coal water slurry gasification device and isothermal transformation furnace | |
| CN109232179B (en) | Methanol synthesis process | |
| CN109173940B (en) | Series-parallel methanol synthesis process | |
| CN109180430B (en) | Methanol synthesis process | |
| CN109173939B (en) | Water-cooling methanol synthesis reactor | |
| CN109279573B (en) | Isothermal transformation process matched with coal water slurry gasification | |
| CN109012506B (en) | Methanol synthesis water-cooling reactor | |
| CN109232180B (en) | Temperature-controllable methanol synthesis process | |
| CN110925722B (en) | Isothermal transformation process and isothermal transformation furnace matched with coal chemical device | |
| CN110877896B (en) | Isothermal transformation hydrogen production method matched with pulverized coal gasification device and isothermal transformation furnace | |
| CN111732075A (en) | Combined type heat insulation series temperature control shift converter device and shift process | |
| CN109280568B (en) | Isothermal transformation process matched with pulverized coal gasification | |
| CN110921619B (en) | Multi-flow CO isothermal conversion process matched with pulverized coal gasification and isothermal conversion furnace | |
| CN111115573B (en) | Polygeneration isothermal shift process matched with coal water slurry gasification process and isothermal shift furnace | |
| CN110921621B (en) | Low-steam-ratio poly-generation isothermal transformation process and isothermal transformation furnace matched with pulverized coal gasification | |
| CN111086972B (en) | CO isothermal conversion process and isothermal conversion furnace matched with pulverized coal gasification |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |