CN115321480B - Adiabatic temperature-control type shift converter and water gas shift process - Google Patents
Adiabatic temperature-control type shift converter and water gas shift process Download PDFInfo
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- CN115321480B CN115321480B CN202210974164.9A CN202210974164A CN115321480B CN 115321480 B CN115321480 B CN 115321480B CN 202210974164 A CN202210974164 A CN 202210974164A CN 115321480 B CN115321480 B CN 115321480B
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
- C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
- C01B3/06—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents
- C01B3/12—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide
- C01B3/16—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide using catalysts
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
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- F22G1/14—Steam superheating characterised by heating method using heat generated by chemical reactions
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- C01B2203/0283—Processes for making hydrogen or synthesis gas containing a CO-shift step, i.e. a water gas shift step
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- C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
- C01B2203/08—Methods of heating or cooling
- C01B2203/0805—Methods of heating the process for making hydrogen or synthesis gas
- C01B2203/0838—Methods of heating the process for making hydrogen or synthesis gas by heat exchange with exothermic reactions, other than by combustion of fuel
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
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Abstract
The application discloses an adiabatic temperature-control converter, which comprises a shell extending along the vertical direction, wherein a first reaction zone and a second reaction zone are arranged in the shell along the height direction, and a cold shock air cavity is arranged between the first reaction zone and the second reaction zone; no heat exchange device is arranged in the first reaction zone; along the height direction, at least three heat exchange tube groups are arranged in the second reaction zone, a feed gas inlet is arranged at the top of the shell, and a conversion gas outlet is arranged at the bottom of the shell. The application also discloses a water gas shift process adopting the heat-insulating temperature-controlling shift converter. The application can control the difference between the highest reaction temperature and the lowest reaction temperature in the second reaction zone to be 30-40 ℃, and can ensure that the reaction temperature in the second reaction zone from top to bottom moves smoothly along an arc line, so that the reaction temperature in the second reaction zone is in the highest reaction temperature zone.
Description
Technical Field
The application relates to an adiabatic temperature-control type shift converter and a water gas shift process using the same, and belongs to the field of water gas shift devices.
Background
In order to fully utilize the reaction heat, the shift converter is generally designed into an adiabatic structure, and the shift converter adopting the adiabatic structure needs to have a good heat removal system so as to timely transfer the reaction heat out of the shift converter and keep the reaction temperature in the shift converter within a proper temperature range so as to keep high reaction efficiency. In the prior art, hot water is generally used as a heat exchange medium to form a steam-water mixture, and flash evaporation is carried out to obtain high-grade steam, wherein a heat exchange device adopts a heat exchange tube array. Due to the innovation of the technology, the content of CO in the existing water gas is high and can reach about 70% at maximum, so that the temperature rise of the shift converter is fast in the axial direction when the shift converter works, and the phenomenon of 'flying temperature' is easy to generate. In order to avoid the phenomenon of 'flying temperature', a mode of connecting a plurality of conversion furnaces in series is generally adopted for production, and mediums with different temperatures are adopted for removing the reaction heat.
The water gas is transformed by adopting a mode that a plurality of transformation furnaces are connected in series, and the phenomenon of 'flying temperature' can be solved to a certain extent, but the transformation device has more equipment, the control points are increased, the process control difficulty is increased, and the purchase cost of the equipment is increased.
Disclosure of Invention
In order to furthest reduce or avoid the phenomenon of 'flying temperature', the application firstly provides an adiabatic temperature-control type converter which comprises a shell extending along the vertical direction, wherein a first reaction zone and a second reaction zone are arranged in the shell along the height direction, the first reaction zone is positioned above the second reaction zone, a cold shock air cavity is arranged between the first reaction zone and the second reaction zone, and the cold shock air pipe is communicated with the cold shock air cavity;
a first catalyst support grid is arranged at the bottom of the first reaction zone; a second catalyst support grid is arranged at the bottom of the second reaction zone; no heat exchange device is arranged in the first reaction zone; at least three heat exchange tube groups are arranged in the second reaction zone along the height direction, wherein the heat exchange tube group positioned at the uppermost layer is called a first-stage heat exchange tube group, the heat exchange tube group positioned at the lowermost layer is called a last-stage heat exchange tube group, and the heat exchange tube group positioned between the first-stage heat exchange tube group and the last-stage heat exchange tube group is called an intermediate heat exchange tube group; the top of the shell is provided with a feed gas inlet, and the bottom of the shell is provided with a conversion gas outlet. And two adjacent heat exchange tube groups are arranged at intervals.
In the shift converter, two first reaction areas and two second reaction areas are arranged along the height direction, no heat exchange device is arranged in the first reaction area, and only the heat exchange device is arranged in the second reaction area.
The main function of the first reaction zone is to smoothly raise the reaction temperature of the water gas to the set reaction temperature zone, so that in the first reaction zone, the reaction temperature is in the raising stage, the residence time of the water gas in the first reaction zone is properly controlled, and under the cooling effect of the cold shock gas in the cold shock gas cavity, the reaction gas can enter the second reaction zone at the set temperature, and the temperature fluctuation of the water gas when entering the first reaction zone is eliminated. In addition, in the initial reaction stage of water gas, coking is easy to generate, an independent first reaction zone is arranged, so that the first catalyst in the first reaction zone can be conveniently and independently replaced, the replacement frequency of the second catalyst in the second reaction zone is reduced, in the prior art, all catalysts need to be replaced according to the coking condition of the catalyst at the air inlet end in a shift converter with a single reaction zone, and most of the catalysts are still in an effective reaction stage in practice, so that a large number of effective catalysts are replaced, and the running cost is increased.
In the second reaction zone, a plurality of heat exchange tube groups are arranged from top to bottom, so that independent temperature regulation and control can be carried out on the reaction zones with different heights in the second reaction zone, the reaction temperature of the whole second reaction zone can be in the optimal reaction temperature, and the production efficiency can be improved. In the prior art, when the tube array heat exchange device extending along the height direction is adopted, the temperature of the heat transfer medium is gradually increased along the flow direction of the heat transfer medium no matter the heat transfer medium adopts a countercurrent mode or a concurrent mode, the heat exchange effect is reduced, and in order to avoid the phenomenon of 'flying temperature', the highest reaction temperature in the conversion furnace is generally limited, so that the maximization of the production efficiency is limited under the condition that the reaction temperature of a part of the area is lower. In some production processes, in order to improve the production efficiency, the upper limit of the reaction temperature is slightly lower than the temperature point generating the 'flying temperature', but in actual operation, the fluctuation of the water gas is extremely easy to cause the reaction temperature to exceed the standard, and the 'flying temperature' phenomenon is generated, so that the difficulty of process control is increased.
In the application, as the plurality of heat exchange tube groups are arranged in the axial direction, the dosage of heat transfer medium, the inlet temperature and the outlet temperature of each heat exchange tube group can be independently adjusted, thereby accurately controlling the reaction temperature of each region in the axial direction in the second reaction region and keeping the reaction temperature of the second reaction region stable. The application can control the temperature difference between the highest reaction temperature and the lowest reaction temperature in the second reaction zone to be 30-40 ℃, and the reaction temperature from the uppermost side to the lowermost side of the second reaction zone can smoothly move along an arc line, so that the reaction temperature in the second reaction zone is in the highest reaction temperature zone, and the change of the reaction temperature in the same height layer in the second reaction zone is controlled to be 1-3 ℃.
In the prior art, the reaction temperature in the same height layer is changed within 6-8 ℃, and in the prior art, the reaction temperature is greatly changed mainly due to the addition of cold shock gas and the fluctuation of the flow of a heat exchange medium. At present, in order to control the reaction temperature, part of raw material gas is used as cold shock gas and is supplemented into the reactor from the middle part of the reactor, and in the production process, the stability of the feeding amount and the feeding temperature of the raw material gas is kept as much as possible so as to ensure that the reaction is carried out stably, but the raw material gas always generates certain fluctuation, so that the fluctuation of the cold shock gas is guided, and the fluctuation of the local reaction temperature in the reactor is increased; on the other hand, the heat transfer medium generally adopts a steam-water mixture, and in the whole reactor, the same heat exchange tube penetrates through the whole reaction area in the height direction, and because of adopting countercurrent heat exchange, the heat transfer medium flows from bottom to top, when reaching the highest reaction area, the heat transfer function of the heat transfer medium is greatly reduced, in the existing production process, the reaction temperature is often controlled in the highest reaction area, once the reaction temperature fluctuates, overtemperature is generated, the phenomenon of 'flying temperature' is easy to generate, and in order to avoid the phenomenon of 'flying temperature', when the reaction temperature upwards exceeds the set temperature, the reaction temperature is quickly moved downwards, and when the flow of the heat transfer medium is regulated, the fluctuation of the reaction temperature is often excessively regulated, so that the fluctuation of the reaction temperature is increased.
In the application, as the plurality of heat exchange tube groups are arranged in the second reaction zone, the reaction temperature of each zone can be independently adjusted in time, and the temperature fluctuation range of the reaction zone is reduced. And the parameters of the heat medium in the first-stage heat exchange tube group can be timely adjusted according to the changes of the air inlet and cold shock air quantity, and the change of the temperature of the top area of the second reaction area is reduced, so that the influence on the reaction temperature of the whole second reaction area is avoided.
Further, in order to avoid the phenomenon of "flying temperature" generated by the exceeding of the reaction temperature in the first reaction zone, and to concentrate the reaction mainly in the second reaction zone, so as to improve the recovery of the reaction heat, the height ratio of the first reaction zone to the second reaction zone is 1: (2-5). Because the first reaction zone is an initial reaction zone of the raw material gas, the temperature of the raw material gas is relatively low, and a large amount of reaction heat can be absorbed, before the height of the first reaction zone is controlled in a certain proportion range, the temperature of the reaction mixture gas does not reach the temperature generating the 'flying temperature' phenomenon, the reaction mixture gas enters the cold shock gas cavity, the temperature of the reaction mixture gas is reduced, meanwhile, the cold shock gas in the cold shock gas cavity can inhibit the temperature in the first reaction zone, and the 'flying temperature' phenomenon in the first reaction zone is avoided. However, the height of the first reaction zone is not too high, and the temperature of the reaction mixture gradually increases as the reaction proceeds, so that the temperature of the reaction mixture is extremely easy to exceed the set temperature and a "fly-temperature" phenomenon is generated, and therefore, the loading height of the first catalyst in the first reaction zone is preferably controlled within 1.5-2.5 m, and the temperature of the reaction mixture can be effectively prevented from exceeding the set temperature within the loading height range of the first catalyst.
Further, each heat exchange tube group comprises an inlet tube, an outlet tube and a plurality of heat exchange tubes with two ends respectively connected to the inlet tube and the outlet tube, and at least two spiral heat exchange tubes are included in the plurality of heat exchange tubes in the same heat exchange tube group and extend spirally around the central axis of the shell; a gap is arranged between two adjacent heat exchange pipes. The gap between adjacent heat exchange tubes is controlled between 50-150 mm. Preferably, all of the heat exchange tubes in each heat exchange tube group are spiral heat exchange tubes.
The design can enable the heat exchange tubes to be uniformly arranged in the second reaction zone and uniformly absorb the reaction heat in the second reaction zone, so that the reaction temperature in each place in the second reaction zone is relatively uniform.
Further, in order to make the reaction temperature in the second reaction zone change steadily, the heat transfer medium in the first-stage heat exchange tube group and the last-stage heat exchange tube group is boiler water, and the heat transfer medium in all the middle heat exchange tube groups is saturated steam. After the reaction mixture in the cold shock gas cavity enters the second reaction zone, the reaction temperature is in an ascending stage, so that the first-stage heat exchange tube group at the upper layer adopts boiler water as a heat transfer medium, and the reaction heat can be smoothly absorbed. In the lower region of the second reaction zone, the effective reaction is greatly reduced at the end of the reaction, the amount of reaction heat generated is also relatively low, and boiler water is used to enable satisfactory absorption of the reaction heat. In the middle area of the second reaction area, the saturated steam is used as a heat transfer medium for reaction, so that the saturated steam is changed into superheated steam, the reaction temperature of the middle area of the second reaction area is in a higher setting range, the temperature and the flow rate of the saturated steam can be independently regulated to control the reaction temperature of the middle area, the reaction temperature fluctuation of the middle heat exchange tube group in the reaction area is controlled within +/-1.5 ℃, the reaction temperature is kept in the highest setting reaction temperature area, the upward exceeding of the reaction temperature is effectively avoided, and the phenomenon of 'flying temperature' is avoided.
Specifically, the first boiler water is used as a heat transfer medium of the first-stage heat exchange tube group, and the first boiler water is formed into first saturated steam after passing through the first-stage heat exchange tube group; the second boiler water is used as a heat transfer medium of the final heat exchange tube group, and the second boiler water is formed into third boiler water after passing through the final heat exchange tube group; the second saturated steam is used as a heat transfer medium of the intermediate heat exchange tube group, and the second saturated steam is formed into superheated steam after passing through the intermediate heat exchange tube group. In an embodiment, at least part of the first saturated steam is used as the second saturated steam.
The first-stage heat exchange tube group is positioned at the uppermost layer of the second reaction zone, so that the first boiler water passes through the first-stage heat exchange tube group to form first saturated steam, and the reaction temperature of the zone where the first-stage heat exchange tube group is positioned can be smoothly increased to the highest set reaction temperature zone, so that the conversion efficiency of CO is ensured. The final heat exchange tube group is positioned at the lowest layer of the second reaction zone, the effective reaction is greatly reduced because the final stage of the reaction is performed, the generated reaction heat is relatively low, the second boiler water is only formed into third boiler water, and the second boiler water is still kept in a liquid state, so that the reaction temperature can be gradually reduced from top to bottom in the reaction zone where the final heat exchange tube group is positioned, and the overhigh outlet temperature of the converted gas is avoided.
The middle heat exchange tube group is positioned in the middle area of the second reaction zone, so that the second saturated steam is converted into superheated steam, the reaction temperature of the middle area can be positioned in the highest set range, and the reaction temperature is positioned in the most efficient reaction zone, so that the reaction efficiency is improved. The flow rate and the temperature of the second saturated steam flowing through each intermediate heat exchange tube group can be independently adjusted, so that the reaction temperature of the reaction area where the intermediate heat exchange tube group is positioned can be kept stable, and the fluctuation of the reaction temperature can be kept within the range of +/-1.5 ℃.
The application further discloses a water gas shift process, which is carried out by adopting the heat-insulating temperature-control shift furnace, and comprises the following steps:
(1) The water gas enters the shell through the raw gas inlet, then flows downwards through the first reaction zone, the cold shock gas cavity and the second reaction zone in sequence, reacts to generate conversion gas, and is discharged from the conversion gas outlet;
(2) Cold shock gas enters the cold shock gas cavity from the cold shock gas pipe;
(3) The first boiler water enters the first-stage heat exchange tube group, and after the reaction heat is absorbed, the first boiler water is formed into first saturated steam and is discharged out of the first-stage heat exchange tube group; the second boiler water enters the final heat exchange tube group, and after the reaction heat is absorbed, the second boiler water is formed into third boiler water and is discharged out of the final heat exchange tube group; the second saturated steam enters the middle heat exchange tube group, is formed into superheated steam after absorbing reaction heat, and is discharged out of the middle heat exchange tube group.
In the water gas shift process, cold shock gas is utilized to stabilize the temperature of the reaction gas from the first reaction zone to the second reaction zone, so that the reaction gas enters the second reaction zone to be kept within a set range, the temperature fluctuation of the water gas when entering the first reaction zone is eliminated, and when the reaction is carried out, the reaction temperature in each zone corresponding to each heat exchange tube group can be independently regulated due to the fact that the temperature and the flow of a heat transfer medium in each heat exchange tube group can be independently regulated, and the reaction temperature in the second reaction zone can be strictly reacted according to a set temperature curve.
Specifically, in order to fully ensure the production efficiency of the shift converter, the highest reaction temperature in the first reaction zone is 380-400 ℃; the inlet temperature of the second reaction zone is 380-400 ℃, and the outlet temperature of the second reaction zone is 410-440 ℃; in the second reaction zone, the reaction temperature is gradually increased from 380-400 ℃ to 435-440 ℃ and then gradually reduced to 400-410 ℃ from top to bottom;
the inlet temperature of the water gas is 220-240 ℃, the outlet temperature of the converted gas is 410-440 ℃, and the reaction pressure is 6.3-7.0MPaG;
the inlet temperature of the first boiler water is 180-190 ℃, and the outlet temperature of the first saturated steam is 240-250 ℃; the inlet temperature of the second boiler water is 210-230 ℃, and the outlet temperature of the third boiler water is 10-20 ℃ higher than the inlet temperature of the second boiler water;
the inlet temperature of the second saturated steam is 240-250 ℃, and the outlet temperature of the superheated steam is 430-440 ℃.
The upper region of the second reaction zone is in the reaction temperature raising stage, the first boiler water is adopted to absorb the reaction heat smoothly and raise the reaction temperature gradually, and the lower region of the second reaction zone has the final stage, so that the heat produced in the reaction is reduced greatly.
And in the middle area of the second reaction zone, the second saturated steam is converted into superheated steam, so that the reaction temperature of the middle area is kept in a high-temperature area. The reaction is allowed to proceed at a higher efficiency under the limitations of the above parameters.
Preferably, at least part of the first saturated steam is used as the second saturated steam in order to reduce the external supply of the second saturated steam. The design can correspondingly reduce the consumption of the first saturated steam delivery pipeline and reduce the equipment investment cost.
Further, in order to control the temperature of the reaction gas entering the second reaction zone, the addition amount of the cold shock gas is 10-30wt% of the water gas inflow, and the inlet temperature of the cold shock gas is 220-240 ℃.
Further, in the case of fully utilizing the first reaction zone to perform the reaction, in order to avoid the reaction temperature of the water gas in the first reaction zone from being over-temperature, the air speed of the water gas in the first reaction zone is 500-800h -1 . The air speed of the air tower is too low to fully utilize the first reaction zone, and too high, a large amount of reaction heat is accumulated in the first reaction zone, so that the air tower is over-temperature and easy to produce a coking phenomenon.
Drawings
Fig. 1 is a schematic structural view of an embodiment of the present application.
Fig. 2 is a schematic view of the structure of the heat exchange tube group.
Detailed Description
The structure of the adiabatic temperature-controlled converter will be described first below with reference to fig. 1 and 2, and the adiabatic temperature-controlled converter includes a housing 10 extending in a vertical direction, the housing including a cylindrical body 11 extending in a vertical direction, an upper end cap 12 welded to the top of the body, and a lower end cap 13 welded to the bottom of the body, and a skirt 19 is installed at the bottom of the housing 10. The upper head 12 is provided with a feed gas inlet 14, and the lower head is provided with a change-over gas outlet 15. Namely, a feed gas inlet is arranged at the top of the shell, and a conversion gas outlet is arranged at the bottom of the shell. A first manhole 16 is also mounted on the upper head, and a second manhole 17 is mounted on the lower head.
A first reaction zone 50 and a second reaction zone 20 are arranged in the shell along the height direction, wherein the first reaction zone 50 is positioned above the second reaction zone 20, a cold shock air cavity 40 is arranged between the first reaction zone 50 and the second reaction zone 20, a ring-shaped cold shock air pipe 41 is arranged in the cold shock air cavity 40, a cold shock air inlet pipe 42 is connected to the cold shock air pipe 41, the cold shock air inlet pipe 42 is welded on the cylinder body, and one end of the cold shock air inlet pipe 42, which is away from the cold shock air pipe 41, extends out of the cylinder body 11 to form a cold shock air inlet 43. Cold shock holes are formed in both the upper and lower sides of the cold shock pipe 41.
In this example, the ratio of the first height H of the first reaction zone to the second height S of the second reaction zone is 1:2.8, it will be appreciated that in other embodiments, the ratio of the first height H to the second height may also be 1:2. 1:2.5, 1:3, 1:4 or 1:5, but may be 1: (2-5) other ratios between (2-5).
A first catalyst support grid 51 is installed at the bottom of the first reaction zone 50, a first catalyst grid cover plate 52 is installed at the top of the first reaction zone 50, and a space between the first catalyst support grid 51 and the first catalyst grid cover plate 52 becomes a first reaction chamber 53 where the first catalyst is stacked. The space at the upper portion of the first catalyst grid cover plate 52 is formed as a gas distribution chamber 55, and the raw material gas inlet 14 communicates with the gas distribution chamber 55.
The first catalyst discharge pipe 54 is installed on the cylinder, and the first catalyst discharge pipe 54 extends into the first reaction chamber 53 from bottom to top in an inclined direction and is communicated with the first reaction chamber, and the lower end of the inlet of the first catalyst discharge pipe 54, which is positioned in the first reaction chamber, is flush with the upper surface of the first catalyst support grid 51, so that the first catalyst in the first reaction chamber 53 can be smoothly discharged from the first catalyst discharge pipe 54, and the first catalyst is replaced.
A second catalyst support grid 21 is installed at the bottom of the second reaction zone 20, a second catalyst grid cover plate 22 is installed at the top of the second reaction zone 20, and a space between the second catalyst support grid 21 and the second catalyst grid cover plate 22 becomes a second reaction chamber 23 where the second catalyst is stacked.
A second catalyst discharge pipe 24 is installed on the second catalyst support grid 21, the upper end of the second catalyst discharge pipe 24 penetrates through the second catalyst support grid 21 upwards and then is communicated with the second reaction cavity 23, and the lower end of the second catalyst discharge pipe 24 extends out of the lower seal head upwards. The upper end surface of the second catalyst discharge pipe 24 is flush with the upper surface of the second catalyst support grid 21.
Three heat exchange tube groups are arranged in the second reaction zone in the height direction, and two adjacent heat exchange tube groups are arranged at intervals, wherein the heat exchange tube group located at the uppermost layer is called a first-stage heat exchange tube group 301, the heat exchange tube group located at the lowermost layer is called a final-stage heat exchange tube group 303, and the heat exchange tube group located between the first-stage heat exchange tube group 301 and the final-stage heat exchange tube group 303 is called an intermediate heat exchange tube group 302, i.e., only one intermediate heat exchange tube group is present in this embodiment. It will be appreciated that in other embodiments, a plurality of intermediate heat exchange tube groups, such as 2, 3, 4 or 5 intermediate heat exchange tube groups, may be disposed between the first heat exchange tube group 301 and the final heat exchange tube group 303, so that not only more external tubes need to be added, but also more tube penetrating holes need to be formed in the housing, which affects the uniformity of the housing structure.
The heat exchange tube groups are identical in structure, and a specific structure of the heat exchange tube group will be described below taking a first-stage heat exchange tube group 301 as an example, the first-stage heat exchange tube group 301 including an inlet annular tube 31 and an outlet annular tube 32 installed in the second reaction zone, the inlet annular tube 31 being located above the outlet annular tube 32. The inlet pipe 311 is connected to the inlet ring pipe 31, which is mounted to the housing and protrudes outward from the housing. The outlet pipe 321 is connected to an outlet annular pipe which is mounted to the housing and extends outwardly from the housing.
Six heat exchange tubes 33 are connected between the inlet annular tube 31 and the outlet annular tube 32, all the heat exchange tubes are spiral heat exchange tubes, the spiral heat exchange tubes spirally extend around the central line axis of the shell, and gaps are formed between adjacent spiral heat exchange tubes, namely gaps are formed between adjacent heat exchange tubes. In the application, the distance between the adjacent heat exchange pipes is controlled to be 50-150mm, and in particular, in the embodiment, the distance between the adjacent heat exchange pipes is controlled to be 80-120mm.
In this embodiment, no heat exchange device is disposed in the first reaction zone.
In this embodiment, the first boiler water is used as a heat transfer medium of the first-stage heat exchange tube group, and the first boiler water is formed into first saturated steam after passing through the first-stage heat exchange tube group. The second boiler water is used as a heat transfer medium of the final heat exchange tube group, and the second boiler water is formed into third boiler water after passing through the final heat exchange tube group. The second saturated steam is used as a heat transfer medium of the intermediate heat exchange tube group, and the second saturated steam is formed into superheated steam after passing through the intermediate heat exchange tube group. In this embodiment, the heat transfer mediums in the first heat exchange tube group and the final heat exchange tube group are boiler water, and the heat transfer medium in the middle heat exchange tube group is saturated steam.
Since only one intermediate heat exchange tube group is provided in this embodiment, the first saturated steam generated by the first-stage heat exchange tube group can be utilized as the second saturated steam as the heat transfer medium of the intermediate heat exchange tube group.
When more than two intermediate heat exchange tube groups are arranged and all the intermediate heat exchange tube groups take second saturated steam as heat transfer media, the first saturated steam generated by the first-stage heat exchange tube group cannot meet the heat transfer media consumption of all the intermediate heat exchange tube groups, and the external saturated steam is required to be used as the heat transfer media of the intermediate heat exchange tube groups.
The following describes a water gas shift process using the above-described adiabatic temperature-controlled shift furnace, the water gas shift process comprising the steps of:
(1) The water gas enters the gas distribution cavity 55 through the raw gas inlet, then flows downwards through the first reaction area, the cold shock cavity and the second reaction area in sequence, reacts to generate conversion gas, and is discharged from the conversion gas outlet;
(2) Cold shock gas enters the cold shock gas cavity from the cold shock gas pipe;
(3) The first boiler water enters the first-stage heat exchange tube group, and after the reaction heat is absorbed, the first boiler water is formed into first saturated steam and is discharged out of the first-stage heat exchange tube group; the second boiler water enters the final heat exchange tube group, and after the reaction heat is absorbed, the second boiler water is formed into third boiler water and is discharged out of the final heat exchange tube group; all the first saturated steam is taken as second saturated steam to enter the middle heat exchange tube group, and after the reaction heat is absorbed, the first saturated steam is formed into superheated steam and is discharged out of the middle heat exchange tube group. When the output of the first saturated steam can not meet the heat transfer requirement of the intermediate heat exchange tube group, the external saturated steam is adopted to make up for the shortage of the consumption of the second saturated steam.
In this example, the inlet temperature of the water gas is 251.+ -. 2 ℃ and the outlet temperature of the shift gas is 407-410 ℃, and the reaction pressures in the first reaction zone and the second reaction zone are 6.3-6.4MPaG.
The inlet temperature of the first boiler water is 183 ℃, and the outlet temperature of the first saturated steam is 248 ℃; the first saturated steam is directly used as the second saturated steam and enters the middle heat exchange tube group, and the outlet temperature of the superheated steam is 445 ℃. The inlet temperature of the second boiler water is 220 ℃, the outlet temperature of the third boiler water is 235 ℃, and the inlet temperature of the third boiler water is 15 ℃ higher than the inlet temperature of the second boiler water.
In the application, the addition amount of the cold shock gas is 5-30wt% of the water gas inflow, and the inlet temperature of the cold shock gas is 220-240 ℃. In particular, in the embodiment, the addition amount of the cold shock gas is 20-25wt% of the water gas inflow, and the inlet temperature of the cold shock gas is 225-230 ℃.
In order to illustrate the beneficial effects of the application, the three heat exchange tube groups in the conversion furnace are replaced by tube array heat exchangers extending along the vertical direction, and 10 temperature measuring points are taken from top to bottom along the height direction in the second reaction zone as comparison examples, the change range of the detected temperature is shown in the following table:
from the table, the application can effectively reduce the temperature change area of each area in the shift converter, improve the stability of the reaction and improve the controllability of the reaction.
Claims (10)
1. The heat-insulating temperature-controlling converter is characterized by comprising a shell extending along the vertical direction, wherein a first reaction zone and a second reaction zone are arranged in the shell along the height direction, the first reaction zone is positioned above the second reaction zone, a cold shock air cavity is arranged between the first reaction zone and the second reaction zone, and the cold shock air pipe is communicated with the cold shock air cavity;
a first catalyst support grid is arranged at the bottom of the first reaction zone, a first catalyst grid cover plate is arranged at the top of the first reaction zone, and a space between the first catalyst support grid and the first catalyst grid cover plate becomes a first reaction cavity for stacking a first catalyst; a second catalyst supporting grid is arranged at the bottom of the second reaction zone, a second catalyst grid cover plate is arranged at the top of the second reaction zone, and a space between the second catalyst supporting grid and the second catalyst grid cover plate becomes a second reaction cavity for stacking a second catalyst; no heat exchange device is arranged in the first reaction zone; at least three heat exchange tube groups are arranged in the second reaction zone along the height direction, wherein the heat exchange tube group positioned at the uppermost layer is called a first-stage heat exchange tube group, the heat exchange tube group positioned at the lowermost layer is called a last-stage heat exchange tube group, and the heat exchange tube group positioned between the first-stage heat exchange tube group and the last-stage heat exchange tube group is called an intermediate heat exchange tube group; the top of the shell is provided with a feed gas inlet, and the bottom of the shell is provided with a conversion gas outlet.
2. The adiabatic temperature-controlled converter of claim 1, wherein the ratio of the heights of the first reaction zone to the second reaction zone is 1: (2-5).
3. The adiabatic temperature-controlled converter as set forth in claim 1, wherein each heat exchange tube group comprises an inlet tube, an outlet tube and a plurality of heat exchange tubes with both ends respectively connected to the inlet tube and the outlet tube, and at least two spiral heat exchange tubes are included among the plurality of heat exchange tubes in the same heat exchange tube group, the spiral heat exchange tubes spirally extending around the central axis of the housing; a gap is arranged between two adjacent heat exchange pipes.
4. The adiabatic temperature-controlled converter of claim 1, wherein the heat transfer medium in the first heat exchange tube bank and the last heat exchange tube bank is boiler water and the heat transfer medium in all intermediate heat exchange tube banks is saturated steam.
5. The adiabatic temperature-controlled converter of claim 1, wherein the first boiler water is used as a heat transfer medium for the primary heat exchange tube bank, and the first boiler water is formed into first saturated steam after passing through the primary heat exchange tube bank; the second boiler water is used as a heat transfer medium of the final heat exchange tube group, and the second boiler water is formed into third boiler water after passing through the final heat exchange tube group; the second saturated steam is used as a heat transfer medium of the intermediate heat exchange tube group, and the second saturated steam is formed into superheated steam after passing through the intermediate heat exchange tube group.
6. A water gas shift process, characterized in that it is carried out using an adiabatic temperature-controlled shift converter according to any one of claims 1 to 5, comprising the steps of:
(1) The water gas enters the shell through the raw gas inlet, then flows downwards through the first reaction zone, the cold shock gas cavity and the second reaction zone in sequence, reacts to generate conversion gas, and is discharged from the conversion gas outlet;
(2) Cold shock gas enters the cold shock gas cavity from the cold shock gas pipe;
(3) The first boiler water enters the first-stage heat exchange tube group, and after the reaction heat is absorbed, the first boiler water is formed into first saturated steam and is discharged out of the first-stage heat exchange tube group; the second boiler water enters the final heat exchange tube group, and after the reaction heat is absorbed, the second boiler water is formed into third boiler water and is discharged out of the final heat exchange tube group; the second saturated steam enters the middle heat exchange tube group, is formed into superheated steam after absorbing reaction heat, and is discharged out of the middle heat exchange tube group.
7. A water gas shift process as defined in claim 6, wherein,
the highest reaction temperature in the first reaction zone is 380-400 ℃;
the inlet temperature of the second reaction zone is 380-400 ℃, and the outlet temperature of the second reaction zone is 410-440 ℃; from top to bottom,
in the second reaction zone, the reaction temperature is gradually increased from 380-400 ℃ to 435-440 ℃ and then gradually reduced to 400-410 ℃;
the inlet temperature of the water gas is 220-240 ℃, the outlet temperature of the converted gas is 410-440 ℃, and the reaction pressures in the first reaction zone and the second reaction are 6.3-7.0MPaG;
the inlet temperature of the first boiler water is 180-190 ℃, and the outlet temperature of the first saturated steam is 240-250 ℃;
the inlet temperature of the second boiler water is 210-230 ℃, and the outlet temperature of the third boiler water is 10-20 ℃ higher than the inlet temperature of the second boiler water;
the inlet temperature of the second saturated steam is 240-250 ℃, and the outlet temperature of the superheated steam is 430-440 ℃.
8. A water gas shift process as defined in claim 6, wherein at least a portion of the first saturated steam is used as the second saturated steam.
9. A water gas shift process according to claim 6, characterized in that the addition amount of cold shock gas is 10-30wt% of the water gas intake amount, and the inlet temperature of cold shock gas is 220-240 ℃.
10. A water gas shift process as claimed in claim 6, wherein in the first reaction zone the volume space velocity of the water gas is in the range of 500 to 800h -1 。
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| CN2245607Y (en) * | 1995-12-15 | 1997-01-22 | 山东省寿光市化工总厂 | Transforming furnace for whole low transformation flow |
| CN1160842A (en) * | 1996-12-31 | 1997-10-01 | 湖北省化学研究所 | Method and equipment for substituting water-atomizing heat exchanger for saturated hot-water tower |
| KR20120111271A (en) * | 2011-03-31 | 2012-10-10 | 주식회사 아세아프로텍 | Flow diversion device for heat exchanger tube cleaning |
| CN103112822A (en) * | 2013-02-21 | 2013-05-22 | 浙江晋巨化工有限公司 | Sulfur-tolerant shift conversion process matched with gasification chilling process |
| CN204182370U (en) * | 2014-10-23 | 2015-03-04 | 新煤化工设计院（上海）有限公司 | A kind of Radial Flow byproduct steam formula isothermal change furnace |
| CN215249547U (en) * | 2021-06-08 | 2021-12-21 | 中国神华煤制油化工有限公司 | System for water gas shift reaction |
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2022
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2245607Y (en) * | 1995-12-15 | 1997-01-22 | 山东省寿光市化工总厂 | Transforming furnace for whole low transformation flow |
| CN1160842A (en) * | 1996-12-31 | 1997-10-01 | 湖北省化学研究所 | Method and equipment for substituting water-atomizing heat exchanger for saturated hot-water tower |
| KR20120111271A (en) * | 2011-03-31 | 2012-10-10 | 주식회사 아세아프로텍 | Flow diversion device for heat exchanger tube cleaning |
| CN103112822A (en) * | 2013-02-21 | 2013-05-22 | 浙江晋巨化工有限公司 | Sulfur-tolerant shift conversion process matched with gasification chilling process |
| CN204182370U (en) * | 2014-10-23 | 2015-03-04 | 新煤化工设计院（上海）有限公司 | A kind of Radial Flow byproduct steam formula isothermal change furnace |
| CN215249547U (en) * | 2021-06-08 | 2021-12-21 | 中国神华煤制油化工有限公司 | System for water gas shift reaction |
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| CN115321480A (en) | 2022-11-11 |
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