CN116239127A - Synthetic ammonia hot standby process and synthetic tower - Google Patents
Synthetic ammonia hot standby process and synthetic tower Download PDFInfo
- Publication number
- CN116239127A CN116239127A CN202310122158.5A CN202310122158A CN116239127A CN 116239127 A CN116239127 A CN 116239127A CN 202310122158 A CN202310122158 A CN 202310122158A CN 116239127 A CN116239127 A CN 116239127A
- Authority
- CN
- China
- Prior art keywords
- synthesis
- tower
- heat
- layer
- reaction
- 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.)
- Pending
Links
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 114
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 57
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 143
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 141
- 239000003054 catalyst Substances 0.000 claims abstract description 27
- 239000012495 reaction gas Substances 0.000 claims description 65
- 238000006243 chemical reaction Methods 0.000 claims description 64
- 239000007789 gas Substances 0.000 claims description 52
- 238000010438 heat treatment Methods 0.000 claims description 44
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 38
- 229910052757 nitrogen Inorganic materials 0.000 claims description 19
- 230000004913 activation Effects 0.000 claims description 15
- 230000035939 shock Effects 0.000 claims description 13
- 238000011084 recovery Methods 0.000 claims description 5
- 230000002194 synthesizing effect Effects 0.000 claims description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 238000012423 maintenance Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 19
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 238000002360 preparation method Methods 0.000 abstract description 4
- 239000000376 reactant Substances 0.000 description 10
- 238000005457 optimization Methods 0.000 description 8
- 238000005485 electric heating Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 3
- 238000004321 preservation Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/04—Preparation of ammonia by synthesis in the gas phase
- C01C1/0405—Preparation of ammonia by synthesis in the gas phase from N2 and H2 in presence of a catalyst
- C01C1/0417—Preparation of ammonia by synthesis in the gas phase from N2 and H2 in presence of a catalyst characterised by the synthesis reactor, e.g. arrangement of catalyst beds and heat exchangers in the reactor
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/04—Preparation of ammonia by synthesis in the gas phase
- C01C1/0405—Preparation of ammonia by synthesis in the gas phase from N2 and H2 in presence of a catalyst
- C01C1/0482—Process control; Start-up or cooling-down procedures
-
- 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
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Analytical Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
Abstract
The invention relates to the technical field of synthesis and preparation of ammonia, in particular to a synthesis ammonia hot standby process and a synthesis tower, wherein the structure of the synthesis tower is optimally designed, and the hot standby of the synthesis tower can be realized by independently controlling the temperature inside the synthesis tower through an outer hot standby layer and an inner hot standby layer. The hot standby process provided by the invention can keep the temperature inside the synthesis tower uniform and above the starting temperature of the catalyst in the ammonia production system which is frequently parked, can quickly reach the ammonia production working condition and enter the ammonia production operation when the ammonia production is required to be started, greatly improves the restarting efficiency after parking, and improves the starting efficiency and the flexibility of the ammonia production system; the whole ammonia synthesis system is prevented from being circularly heated, and the energy consumption of hot standby is reduced.
Description
Technical Field
The invention relates to the technical field of synthesis and preparation of ammonia, in particular to a synthesis ammonia hot standby process and a synthesis tower.
Background
The system temperature and pressure can be reduced during the stop of the ammonia synthesis device, and each time the device is restarted to raise the temperature and the pressure, the time of hours or even days can be consumed, and the effective operation time of the device is reduced. In order to shorten the time to restart, it is necessary to put the ammonia synthesis tower in a hot standby state.
After the traditional ammonia synthesis device is stopped, the device is started, and a circulating gas compressor and a start-up heating furnace are required to be started to heat the whole synthesis loop in series. The temperature of the gas in the loop is increased to more than 350 ℃ by a heating furnace before the gas enters the synthesis tower; after exiting the synthesis column, the gas was cooled to about 40 ℃ before being boosted in the recycle gas compressor. The system is driven by cold and hot energy, and has large energy consumption and long duration.
Therefore, the existing hot standby technology of the synthetic ammonia equipment still has a need to be improved, and needs to be adjusted, optimized and improved to improve the hot standby efficiency, reduce the restarting time after stopping, and further improve the production efficiency of synthetic ammonia. Therefore, a more reasonable technical scheme needs to be provided, and the technical problems in the prior art are solved.
Disclosure of Invention
At least to overcome one of the defects mentioned above, the invention provides a synthesis ammonia hot standby process and a synthesis tower, which simplify the synthesis ammonia hot standby process by optimizing the equipment structure, maintain the temperature in the synthesis tower higher than the catalyst activation temperature, and only consume the energy which is the heat dissipation loss of the synthesis tower, thereby facilitating the rapid restarting and recovery production of the device. The process does not need to serially connect the whole synthesis loop for hot standby, and compared with the traditional process, the driving time and energy consumption are greatly saved.
In order to achieve the above purpose, the hot standby process disclosed by the invention can adopt the following technical scheme:
a synthetic ammonia thermal recovery process comprising:
stopping introducing hydrogen into the synthesis tower, continuously introducing nitrogen into the synthesis tower, and simultaneously controlling the air discharge amount to maintain the stable gas flow and pressure in the synthesis tower;
determining the activation temperature required by the catalyst for synthesizing ammonia, and setting a temperature value higher than the activation temperature as a hot standby temperature;
the synthesis tower is internally provided with a heat tracing structure, the heat tracing structure comprises an outer heat tracing layer for tracing the inner side wall surface of the synthesis tower and an inner heat tracing layer for tracing the reaction bed layer in the synthesis tower, and the outer heat tracing layer and the inner heat tracing layer work together to maintain the internal temperature balance of the synthesis tower;
the temperature inside the synthesis tower is monitored, and an alarm is given when the temperature inside the synthesis tower is lower than the activation temperature of the catalyst.
The hot standby technology disclosed by the invention can be used for heating the synthesis tower under the cold driving working condition, and also can be used for preserving the heat of the synthesis tower during the stopping period or the low-load operation. Through continuous nitrogen and low-flow quantity control emptying, the flow and the air pressure of the air flow in the synthesis tower are kept stable, and the temperature in the synthesis tower can be kept balanced. When the synthesis tower is hot-standby, the heat tracing structure enables the internal environment temperature and the catalyst bed temperature to reach the hot-standby temperature value, so that the temperature required by catalyst activation is met, the subsequent realization of rapid starting operation is facilitated, the starting efficiency of an ammonia synthesis process is improved, and the delay influence of frequent starting and stopping on effective production time is reduced.
Further, in the present invention, the outer heat tracing layer is used for heating and heat preservation, and the specific working mode is not limited only, and optimization is performed and one of possible choices is provided herein: the outer heat tracing layer envelops the inner side wall surface of the synthesis tower, and radiates heat from the inner side wall surface to the inside of the synthesis tower to heat tracing to maintain the temperature. When the scheme is adopted, the outer heat tracing layer can be heated by adopting an electric heat tracing band or other structures to form a surface, and the interior of the synthesis tower is uniformly and synchronously heated through the circumferential heating structure.
Further, the arrangement mode and the position of the inner heat tracing layer are different from those of the outer heat tracing layer, and are not limited solely, and optimization is performed and one of the possible choices is provided in the invention: the inner heat tracing layer is arranged in the reaction bed layer and extends in a bending mode in the reaction bed layer to envelop the reaction bed layer structure, and the inner heat tracing layer directly radiates heat to the inner space of the synthesis tower to carry out heat tracing maintenance temperature. When the scheme is adopted, the inner heat tracing layer is heated in the reaction bed layer, so that the internal temperature of the reaction bed layer is raised and maintained, the purpose of heat standby is achieved, and the start-up can be rapidly completed when the start-up is needed.
Further, in order to improve the effect of the hot standby or improve the efficiency of the hot standby, the switching between driving is realized more quickly, and optimization is performed and one of possible choices is provided here: the middle part of the synthesis tower is provided with a heating structure and a heat exchange structure, and when hot standby is needed, the heating structure and the heat exchange structure always keep an open working state. When the scheme is adopted, the heating structure and the heat exchange structure can adopt the structure originally used for gas heating and heat exchange in the synthesis tower, so that the structure is not only used for preheating and heat exchange in the process of cold start and normal operation of the synthesis ammonia, but also plays an auxiliary role in the hot standby process, and the hot standby effect and efficiency are improved.
Still further, in the present invention, the structure of the electric heater and the structure of the heat exchanger for heating are not limited only, and optimization is made herein and one of possible choices is presented: the heating structure comprises an electric heater, the heat exchange structure comprises a plurality of heat exchangers, and the electric heater and the heat exchangers preheat and heat up the nitrogen entering the synthesis tower, so that the nitrogen reaches the hot standby temperature. When the scheme is adopted, the electric heater can adopt structures such as an electric heating tube, an electric heating wire and the like, and generates heat after being electrified, so that the temperature in the synthesis tower can be increased.
The invention also discloses a synthesis tower for hot standby, and the synthesis tower is specifically described herein.
A synthesis tower for hot standby comprises a closed tower body, wherein an inner shell is arranged in the tower body, and a shell gap is formed between the inner shell and the tower body; a plurality of reaction beds are sequentially arranged in the inner shell along the longitudinal direction, and adjacent reaction beds are communicated and form a unidirectional airflow passage; the tower body is provided with a plurality of reaction gas inlets and cold shock gas inlets for guiding the reaction gas and the cold shock gas to enter the airflow passage after being mixed; an outer heat tracing layer is arranged in the shell gap, an inner heat tracing layer is arranged in the reaction bed layer in an extending manner, a heating structure and a heat exchange structure are arranged in the inner shell and used for exchanging heat for the reaction gas, and the reaction gas passing through the heating structure and the heat exchange structure enters the airflow passage; the tower body is also provided with a reaction gas outlet which is communicated with the gas flow passage and used for discharging the reacted gas.
The synthesis tower disclosed by the above can be filled with reaction gas in the normal production process of synthesizing ammonia, and the internal reaction bed layer is used for realizing the synthesis and preparation of ammonia, and the external heat tracing layer and the internal heat tracing layer are not started under the working condition; the heat standby is carried out in a cold state after the vehicle is stopped, the composition of the introduced air flow is regulated, meanwhile, the constant emptying of a certain flow is kept, only nitrogen is introduced to keep the flow and the air pressure of the air flow inside, the heating work of the inner heat tracing layer and the outer heat tracing layer is started, the heat standby of the synthesis tower is realized, and the rapid start-up of the synthesis work of ammonia is facilitated.
Further, in the present invention, the heat tracing structure of the synthetic tower is optimized and one of the possible choices is presented: the outer heat tracing layer comprises a plurality of electric heat tracing bands which are uniformly arranged along the inner wall surface of the synthesis tower; the inner heat tracing layer comprises a plurality of electric furnace wires spirally wound at least in the uppermost reaction bed layer. When the scheme is adopted, the uppermost reaction bed is heated, and the uniform change of temperature can be realized under the flow of internal nitrogen.
Further, in the present invention, the heating structure is not limited solely, and the interior of the synthesis column may be heated by various structures, and optimization is performed and one of possible options is proposed herein: the inner shell is internally provided with a preheating pipe, the heating structure comprises an electric heater extending to the inside of the preheating pipe, and at least one reaction gas inlet is used for introducing reaction gas into the preheating pipe and preheating the reaction gas through the heating structure; the heat exchange structure comprises a heat exchanger arranged at the reaction bed layer, and the heat exchanger is communicated with the airflow passage and adjusts the temperature of the internal airflow. When the scheme is adopted, the heat exchanger can preheat the reaction gas initially fed into the synthesis tower, and heat exchange and temperature rise are carried out on the reaction gas passing through the reaction bed layer, so that the reaction gas reaches the temperature required by synthesizing ammonia; when in the hot standby state, the heat exchanger can heat nitrogen to raise the temperature of the nitrogen in the synthesis tower, so that the hot standby is promoted.
Still further, in the present invention, the reaction gas may be introduced into the synthesis column from different locations and used for synthesis of ammonia or for performing a hot standby process, and the reaction gas inlet provided on the synthesis column is used for gas introduction, the specific number and location are not limited only, and optimization is performed and one of possible choices is proposed herein: the number of the reaction gas inlets is at least two, and one reaction gas inlet guides the reaction gas to longitudinally enter a preheating pipe from the middle part of the synthesis tower for preheating and mixing with other reaction gas and cold shock gas; the other reaction gas inlet guides the reaction gas to enter the shell gap, exchanges heat from the heat tracing structure and is mixed with other reaction gas and cold shock gas. When the scheme is adopted, the reaction gas longitudinally entering the preheating pipe from the middle is fully preheated, the temperature is quickly increased, and the temperature of the synthetic ammonia or the hot standby temperature is reached; the reaction gas entering from the shell gap can absorb a certain amount of heat and heat, the reaction gas entering from two ways is mixed before entering the reaction bed layer, and the corresponding ammonia synthesis reaction occurs after entering the reaction bed layer or is only used as hot standby gas to flow through.
Further, the structure of the reaction bed and the heat exchanger is not limited solely, and may be configured in various ways to meet the flow and heat exchange requirements of the gas stream, where the following possible choices are optimized and proposed: the reaction bed layer comprises an annular catalyst bed layer, the heat exchanger is arranged in the middle of the catalyst bed layer and is in an annular structure, the preheating pipe penetrates through a middle hole of the heat exchanger, gas inside and outside the heat exchange pipe of the heat exchanger exchanges heat, tower entering gas in the pipe is preheated, and reaction gas outside the pipe is cooled. When the scheme is adopted, the outer side of the reaction bed layer is tightly attached to and sealed with the inner side wall of the inner shell, so that the space between two adjacent reaction bed layers is airtight, and air flow can only directionally flow through the air flow passage.
Compared with the prior art, the technical scheme disclosed by the invention has the following partial beneficial effects:
the hot standby process provided by the invention can keep the temperature inside the synthesis tower uniform and above the starting temperature of the catalyst in an ammonia production system which is frequently parked, can quickly reach the ammonia production working condition and enter the ammonia production operation when the ammonia production is required to be started, greatly improves the restarting efficiency after parking, and improves the starting ammonia production efficiency and flexibility; the whole ammonia production system is prevented from maintaining the hot standby, and the energy consumption of the hot standby is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a synthesis ammonia thermal recovery process.
FIG. 2 is a schematic view showing the internal structure of a synthesis column (in this figure, the reaction gas inlet is located at the lower part of the column body).
FIG. 3 is a schematic view showing the internal structure of a synthesis column (in which the reaction gas inlets are located at the lower and upper portions of the column body).
FIG. 4 is a schematic view showing the internal structure of a synthesis column (in this figure, the reaction gas inlets are located at the lower and top portions of the column body).
In the above figures, the meanings of the various reference numerals are:
1. a tower body; 2. an inner case; 3. an outer heat trace layer; 4. an inner heat trace layer; 5. a reaction bed layer; 6. a heat exchanger; 7. an electric heater; 8. a cold shock gas inlet; 9. a thermocouple; 10. a reactant gas inlet; 11. a reaction gas outlet; 12. preheating pipes.
Detailed Description
The invention is further illustrated by the following description of specific embodiments in conjunction with the accompanying drawings.
In the existing ammonia synthesis process, hot standby is needed to keep the temperature environment in the synthesis tower when frequent shutdown occurs, so that the recovery of the production of the start-up is facilitated, the existing technology has the conditions of larger energy consumption and lower efficiency, and the following embodiments are optimized to overcome the defects in the existing technology.
Example 1
As shown in fig. 1, the present embodiment provides a process for hot standby of synthetic ammonia, which is used for a frequently stopped synthetic ammonia system or a synthetic ammonia system requiring long-term stopping, and the specific process includes:
s01: and stopping introducing hydrogen into the synthesis tower, continuously introducing nitrogen into the synthesis tower, and simultaneously controlling the air discharge amount to maintain the stable gas flow and the stable gas pressure in the synthesis tower.
Preferably, when nitrogen is introduced, the nitrogen can circulate in the synthesis tower in a mode of multiple air inlets, so that the temperature in the synthesis tower is kept balanced; the outward release gas with certain flow is kept, and the purpose is to meet the air circulation requirement in the synthesis tower and keep the uniform transmission of temperature.
S02: determining the activation temperature required by the catalyst for synthesizing ammonia, and setting a temperature value higher than the activation temperature as the hot standby temperature.
Preferably, the hot standby temperature is set to 350 ℃ and the reaction bed 5 is brought to that temperature, and when the reaction bed 5 reaches the hot standby temperature, the temperature can be maintained by intermittent heat supply.
S03: the synthesis tower is internally provided with a heat tracing structure, the heat tracing structure comprises an outer heat tracing layer 3 for tracing the inner shell wall surface of the synthesis tower and an inner heat tracing layer 4 for tracing the reaction bed layer 5 in the synthesis tower, and the outer heat tracing layer 3 and the inner heat tracing layer 4 work together to maintain the internal temperature balance of the synthesis tower.
Preferably, in this embodiment, the outer heat tracing layer 3 is used for heating and heat preservation, and the specific working mode is not limited only, and is optimized and one of possible choices is adopted here: the outer heat tracing layer 3 envelops the wall surface of the inner shell of the synthesis tower, and radiates heat from the wall surface of the inner shell to the reaction bed layer inside the synthesis tower to heat and maintain the temperature. When the scheme is adopted, the outer heat tracing layer 3 can adopt an electric heat tracing belt or other structures to form surface heating, and the inner reaction bed layer of the synthesis tower is uniformly and synchronously heated through the whole circumferential surface-shaped heating structure, so that the temperature of the reaction bed layer is maintained.
The arrangement and position of the inner heat trace layer 4 are different from those of the outer heat trace layer 3, and are not limited to only, and in this embodiment, optimization is performed and one of possible choices is provided: the inner heat tracing layer 4 is arranged in the reaction bed layer 5 and is bent and extended in the reaction bed layer 5 to envelop the structure of the reaction bed layer 5, and the inner heat tracing layer directly radiates heat to the inner space of the synthesis tower to carry out heat tracing maintenance temperature. When the scheme is adopted, the inner heat tracing layer 4 is heated in the reaction bed layer 5, so that the internal temperature of the reaction bed layer 5 is raised and maintained, the purpose of hot standby is achieved, and the driving can be rapidly completed when the driving is needed.
Preferably, in order to improve the effect of the hot standby or improve the efficiency of the hot standby, the driving switch is realized faster, and the embodiment optimizes and adopts one of the possible choices: the middle part of the synthesis tower is provided with a heating structure and a heat exchange structure, and when hot standby is needed, the heating structure and the heat tracing structure always keep an open working state. When the scheme is adopted, the heating structure and the heat exchange structure can adopt the structure originally used for gas heating and heat exchange in the synthesis tower, so that the structure is not only used for preheating and heat exchange in the process of cold start and normal operation of the synthesis ammonia, but also plays an auxiliary role in the hot standby process, and the hot standby effect and efficiency are improved.
In the present embodiment, the structure of the electric heater 7 and the structure of the heat exchanger 6 for heating are not limited only, and the present embodiment is optimized and adopts one of possible choices: the heating structure comprises an electric heater 7, the heat exchange structure comprises a plurality of heat exchangers 6, and the electric heater 7 and the heat exchangers 6 preheat and heat up the nitrogen entering the synthesis tower, so that the nitrogen reaches the hot standby temperature. When the scheme is adopted, the electric heater 7 can adopt structures such as an electric heating tube, an electric heating wire and the like, and can heat and generate heat after being electrified, so that the temperature in the synthesis tower can be increased.
S04: the temperature inside the synthesis tower is monitored, and an alarm is given when the temperature inside the synthesis tower is lower than the activation temperature of the catalyst.
Preferably, the monitoring and alarming of the internal temperature of the synthesis tower can be carried out in various modes, the alarm is carried out when the internal temperature of the synthesis tower does not reach the hot standby temperature, and the alarm is carried out when the internal temperature of the synthesis tower is lower than the activation temperature. Meanwhile, when the temperature in the synthesis tower reaches the hot standby temperature, the alarm is given out after the temperature exceeds the set upper temperature limit.
The hot standby technology disclosed by the invention can be used for heating the synthesis tower under the cold driving working condition, and also can be used for preserving the heat of the synthesis tower during the stopping period or the low-load operation. Through continuous nitrogen and low-flow quantity control emptying, the flow and the air pressure of the air flow in the synthesis tower are kept stable, and the temperature in the synthesis tower can be kept balanced. When the synthesis tower is hot-standby, the heat tracing structure enables the internal environment temperature and the temperature of the reaction bed layer 5 to reach the hot standby temperature value, so that the temperature required by catalyst activation is met, the subsequent realization of rapid starting operation is facilitated, the starting efficiency of an ammonia synthesis process is improved, and the delay influence of frequent starting and stopping on effective production time is reduced.
Example 2
The foregoing embodiment 1 discloses a hot standby process, and this embodiment discloses a synthesis tower for hot standby, which is specifically described herein.
As shown in fig. 2, a synthesis tower for hot standby comprises a closed tower body 1, wherein an inner shell 2 is arranged in the tower body 1, and a shell gap is formed between the inner shell 2 and the tower body 1; a plurality of reaction beds 5 are sequentially arranged in the inner shell 2 along the longitudinal direction, and the adjacent reaction beds 5 are communicated and form a unidirectional airflow passage; the tower body 1 is provided with a plurality of reaction gas inlets 10 and cold shock gas inlets 8 for guiding the reaction gas and the cold shock gas to enter the gas flow passage after being mixed; an outer heat tracing layer 3 is arranged in the shell gap, an inner heat tracing layer 4 is arranged in the reaction bed layer 5 in an extending mode, a heating structure and a heat exchange structure are arranged in the inner shell 2 and used for exchanging heat for the reaction gas, and the reaction gas passing through the heating structure and the heat exchange structure enters the airflow passage; the tower body 1 is also provided with a reaction gas outlet 11, and the reaction gas outlet 11 is communicated with a gas flow passage and is used for discharging the reacted gas.
Preferably, the tower body 1 in this embodiment is provided with a cylindrical structure, the inner shell 2 inside is also provided with a cylindrical structure, and the inner shell 2 and the side wall of the tower body 1 form an annular shell gap.
In the synthesis tower disclosed by the above, reaction gas can be introduced in the normal production process of synthetic ammonia, the inner reaction bed layer 5 is used for realizing the synthesis preparation of ammonia, and the outer heat tracing layer 3 and the inner heat tracing layer 4 are not started under the working condition; the heat standby is carried out in a cold state after the vehicle is stopped, the composition of the introduced air flow is regulated, meanwhile, the constant emptying of a certain flow is kept, only nitrogen is introduced to keep the flow and the air pressure of the air flow inside, the heating work of the inner heat tracing layer and the outer heat tracing layer is started, the heat standby of the synthesis tower is realized, and the rapid start-up of the synthesis work of ammonia is facilitated.
In this embodiment, the heat tracing structure of the synthesis tower is optimized and one of the possible choices is proposed: the outer heat tracing layer 3 comprises a plurality of electric heat tracing bands which are uniformly arranged along the inner wall surface of the synthesis tower; the inner heat tracing layer 4 comprises a plurality of electric furnace wires spirally wound at least in the uppermost reaction bed layer 5. By adopting such a scheme, the uppermost reaction bed 5 is heated, and uniform temperature change can be realized under the flow of internal nitrogen.
Preferably, the outer heat tracing layer 3 adopts an electric heat tracing band, and the inner heat tracing layer 4 adopts a catalyst heating wire for heating. The surface of the tower body 1 is provided with a controller for controlling the start and stop of the outer heat tracing layer 3 and the inner heat tracing layer 4.
In this embodiment, the heating structure may be, but not limited to, a heating structure that heats the interior of the synthesis tower through various structures, where the structure is optimized and one of the possible options is adopted: the inner shell 2 is internally provided with a preheating pipe 12, the heating structure comprises an electric heater 7 extending into the preheating pipe 12, and at least one reaction gas inlet 10 is used for introducing reaction gas into the preheating pipe 12 and preheating the reaction gas through the heating structure; the heat exchange structure comprises a heat exchanger 6 arranged at the reaction bed layer 5, and the heat exchanger 6 is communicated with the airflow passage and adjusts the temperature of the internal airflow. When the scheme is adopted, the electric heater 7 can preheat the reaction gas initially fed into the synthesis tower, and exchange heat with the reaction gas passing through the reaction bed layer 5 to raise the temperature of the reaction gas to the temperature required by ammonia synthesis; when in the hot standby state, the electric heater 7 can heat the gas in the tower to raise the temperature in the synthesis tower and maintain the hot standby state in the tower.
In this embodiment, the reaction gas may be introduced into the synthesis tower from different locations and used for synthesis of ammonia or for performing a hot standby process, and the specific number and location of the reaction gas inlet 10 provided in the synthesis tower are not limited to the only one, and may be optimized and selected as one of possible choices: the number of the reaction gas inlets 10 is at least two, and one reaction gas inlet 10 guides the reaction gas to longitudinally enter a preheating pipe 12 from the middle part of the synthesis tower for preheating and mixing with other reaction gases and cold shock gas; the other reactant gas inlet 10 directs the reactant gas into the shell gap and exchanges heat from the heat trace structure 3 and mixes with other reactant gases and cold shock gas. When the scheme is adopted, the reaction gas longitudinally entering the preheating pipe 12 from the middle is fully preheated, the temperature is quickly increased, and the temperature of the synthetic ammonia or the hot standby temperature is reached; the reaction gas entering from the shell gap can absorb a certain amount of heat and heat up, and the reaction gas entering from two ways is mixed before entering the reaction bed layer 5 and is subjected to corresponding ammonia synthesis reaction after entering the reaction bed layer 5 or is only used as hot standby gas to flow through.
In other technical solutions, the position of the reactant gas inlet 10 may be adjusted, for example, the reactant gas inlet 10 may be further disposed at a lower side of the tower 1, the reactant gas inlet 10 may be disposed at an upper side of the tower 1, or the reactant gas inlet 10 may be disposed at a top of the tower 1; when a plurality of reactant gas inlets 10 are provided, a combination scheme in which the reactant gas inlets 10 are simultaneously provided at different positions may be employed.
The structure of the reaction bed 5 and the heat exchanger 6 is not limited only and can be set in various forms to meet the flow and heat exchange requirements of the gas stream, where the optimization is performed and one possible choice is as follows: the reaction bed 5 comprises an annular catalyst bed, the heat exchanger 6 is arranged in the middle of the catalyst bed, the heat exchanger 6 is configured into an annular shape, and the preheating pipe 12 passes through a middle hole of the heat exchanger 6. When the scheme is adopted, the outer bottom of the reaction bed layer 5 is tightly attached to and sealed with the inner side wall of the inner shell 2, so that the space between two adjacent reaction bed layers 5 is airtight, and air flow can only directionally flow through the air flow passage.
Preferably, a thermocouple 9 is also arranged in the tower body 1 and is used for monitoring and feeding back the temperature in the tower body 1.
The synthetic tower disclosed by the embodiment can be used for heating the synthetic tower under the cold driving working condition and also can be used for preserving heat of the synthetic tower during stopping or low-load operation. An electric heater 7 is arranged in the central tube of the synthesis tower, so that the reaction bed layer of the synthesis tower can be gradually heated from a cold state to the activation temperature of the catalyst. The catalyst electric heating wire arranged on the first catalyst reaction bed layer of the synthesis tower can be used for preserving heat of the catalyst reaction bed layer during stopping or low-load operation, and the temperature of the catalyst reaction bed layer is maintained to be not lower than the activation temperature. Meanwhile, the outer heat tracing layer and the heat preservation layer are arranged outside the first catalyst bed layer, so that heat dissipation of the catalyst bed layer during stopping can be effectively slowed down, the temperature of the first catalyst reaction bed layer is maintained, and the rapid restarting production is facilitated.
The above is an embodiment exemplified in this example, but this example is not limited to the above-described alternative embodiments, and a person skilled in the art may obtain various other embodiments by any combination of the above-described embodiments, and any person may obtain various other embodiments in the light of this example. The above detailed description should not be construed as limiting the scope of the present embodiments, which is defined in the appended claims.
Claims (10)
1. A synthetic ammonia thermal recovery process, comprising:
stopping introducing hydrogen into the synthesis tower, continuously introducing nitrogen into the synthesis tower, and simultaneously controlling the air discharge amount to maintain the stable gas flow and pressure in the synthesis tower;
determining the activation temperature required by the catalyst for synthesizing ammonia, and setting a temperature value higher than the activation temperature as a hot standby temperature;
the synthesis tower is internally provided with a heat tracing structure, the heat tracing structure comprises an outer heat tracing layer (3) for tracing the inner side wall surface of the synthesis tower and an inner heat tracing layer (4) for tracing the reaction bed layer (5) in the synthesis tower, and the outer heat tracing layer (3) and the inner heat tracing layer (4) work together to maintain the internal temperature balance of the synthesis tower;
the temperature inside the synthesis tower is monitored, and an alarm is given when the temperature inside the synthesis tower is lower than the activation temperature of the catalyst.
2. The ammonia synthesis hot standby process according to claim 1, wherein: the outer heat tracing layer (3) envelops the inner side wall surface of the synthesis tower, and radiates heat from the inner side wall surface to the inside of the synthesis tower to heat tracing to maintain the temperature.
3. The ammonia synthesis hot standby process according to claim 1 or 2, characterized in that: the inner heat tracing layer (4) is arranged in the reaction bed layer (5) and is bent and extended in the reaction bed layer (5) to envelop the structure of the reaction bed layer (5), and the inner heat tracing layer directly radiates heat to the inner space of the synthesis tower to carry out heat tracing maintenance temperature.
4. The ammonia synthesis hot standby process according to claim 1, wherein: the middle part of the synthesis tower is provided with a heating structure and a heat exchange structure, and when hot standby is needed, the heating structure and the heat tracing structure always keep an open working state.
5. The ammonia synthesis hot standby process according to claim 4, wherein: the heating structure comprises an electric heater (7), the heat exchange structure comprises a plurality of heat exchangers (6), and the electric heater (7) and the heat exchangers (6) preheat and heat up the nitrogen entering the synthesis tower, so that the nitrogen reaches the hot standby temperature.
6. A synthetic tower, characterized in that: comprises a closed tower body (1), wherein an inner shell (2) is arranged in the tower body (1), and a shell gap is formed between the inner shell (2) and the tower body (1); a plurality of reaction beds (5) are sequentially arranged in the inner shell (2) along the longitudinal direction, and the adjacent reaction beds (5) are communicated and form a unidirectional airflow passage; a plurality of reaction gas inlets (10) and cold shock gas inlets (8) are arranged on the tower body (1) and are used for guiding the reaction gas and the cold shock gas to enter the airflow passage after being mixed; an outer heat tracing layer (3) is arranged in the shell gap, an inner heat tracing layer (4) is arranged in the reaction bed layer (5) in an extending mode, a heating structure and a heat exchange structure are arranged in the inner shell (2) and used for exchanging heat for the reaction gas, and the reaction gas passing through the heating structure and the heat exchange structure enters the airflow passage; the tower body (1) is also provided with a reaction gas outlet (11), and the reaction gas outlet (11) is communicated with the gas flow passage and is used for discharging the reacted gas.
7. The synthesis column according to claim 6, wherein: the outer heat tracing layer (3) comprises a plurality of electric heat tracing bands which are uniformly arranged along the inner wall surface of the synthesis tower; the inner heat tracing layer (4) comprises a plurality of electric furnace wires spirally wound at least in the uppermost reaction bed layer (5).
8. The synthesis column according to claim 6, wherein: a preheating pipe (12) is arranged in the inner shell (2), the heating structure comprises an electric heater (7) extending into the preheating pipe (12), and at least one reaction gas inlet (10) is used for introducing reaction gas into the preheating pipe (12) and preheating the reaction gas through the heating structure; the heat exchange structure comprises a heat exchanger (6) arranged at the reaction bed layer (5), and the heat exchanger (6) is communicated with the airflow passage and adjusts the temperature of the internal airflow.
9. The synthetic tower according to claim 8 wherein: the number of the reaction gas inlets (10) is at least two, and one reaction gas inlet (10) guides the reaction gas to longitudinally enter a preheating pipe (12) from the middle part of the synthesis tower for preheating and mixing with other reaction gases and cold shock gas; the other reaction gas inlet (10) guides the reaction gas to enter the shell gap, exchanges heat from the heat tracing structure and is mixed with other reaction gas and cold shock gas.
10. The synthetic tower according to claim 8 wherein: the reaction bed (5) comprises an annular catalyst bed, the heat exchanger (6) is arranged in the middle of the catalyst bed, the heat exchanger (6) is in an annular structure, and the preheating pipe (12) penetrates through a middle hole of the heat exchanger (6).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310122158.5A CN116239127A (en) | 2023-02-15 | 2023-02-15 | Synthetic ammonia hot standby process and synthetic tower |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310122158.5A CN116239127A (en) | 2023-02-15 | 2023-02-15 | Synthetic ammonia hot standby process and synthetic tower |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116239127A true CN116239127A (en) | 2023-06-09 |
Family
ID=86634545
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310122158.5A Pending CN116239127A (en) | 2023-02-15 | 2023-02-15 | Synthetic ammonia hot standby process and synthetic tower |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116239127A (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3705009A (en) * | 1970-06-12 | 1972-12-05 | Grace W R & Co | Heat recycling for ammonia preparation |
| US4681745A (en) * | 1982-04-14 | 1987-07-21 | Imperial Chemical Industries Plc | Ammonia production process |
| US5935544A (en) * | 1996-06-06 | 1999-08-10 | Brown & Root, Inc. | Moderate excess nitrogen Braun Purifier™ process and method for retrofitting non-Braun Purifier™ ammonia plants |
| CN2751016Y (en) * | 2004-12-09 | 2006-01-11 | 中国寰球工程公司 | Indirect heat exchange type energy-saving ammonia synthesis tower with multi-bed axial combined bed |
| CN103318919A (en) * | 2013-07-11 | 2013-09-25 | 中国成达工程有限公司 | Investment-saving ammonia synthesis process and device |
| CN204848289U (en) * | 2015-08-28 | 2015-12-09 | 中化重庆涪陵化工有限公司 | Ammonia converter waste heat recovery utilizes system |
| CN105883852A (en) * | 2016-04-29 | 2016-08-24 | 湖南安淳高新技术有限公司 | Ammonia synthesis reaction system and method |
| CN107188197A (en) * | 2017-07-04 | 2017-09-22 | 兖矿新疆煤化工有限公司 | Ammonia synthesis catalyst is heated up the method for driving in advance using nitrogen |
| CN110388638A (en) * | 2019-08-01 | 2019-10-29 | 河南晋开化工投资控股集团有限责任公司 | A kind of steam thermal energy utilization process in carbon dioxide stripping their urea production |
-
2023
- 2023-02-15 CN CN202310122158.5A patent/CN116239127A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3705009A (en) * | 1970-06-12 | 1972-12-05 | Grace W R & Co | Heat recycling for ammonia preparation |
| US4681745A (en) * | 1982-04-14 | 1987-07-21 | Imperial Chemical Industries Plc | Ammonia production process |
| US5935544A (en) * | 1996-06-06 | 1999-08-10 | Brown & Root, Inc. | Moderate excess nitrogen Braun Purifier™ process and method for retrofitting non-Braun Purifier™ ammonia plants |
| CN2751016Y (en) * | 2004-12-09 | 2006-01-11 | 中国寰球工程公司 | Indirect heat exchange type energy-saving ammonia synthesis tower with multi-bed axial combined bed |
| CN103318919A (en) * | 2013-07-11 | 2013-09-25 | 中国成达工程有限公司 | Investment-saving ammonia synthesis process and device |
| CN204848289U (en) * | 2015-08-28 | 2015-12-09 | 中化重庆涪陵化工有限公司 | Ammonia converter waste heat recovery utilizes system |
| CN105883852A (en) * | 2016-04-29 | 2016-08-24 | 湖南安淳高新技术有限公司 | Ammonia synthesis reaction system and method |
| CN107188197A (en) * | 2017-07-04 | 2017-09-22 | 兖矿新疆煤化工有限公司 | Ammonia synthesis catalyst is heated up the method for driving in advance using nitrogen |
| CN110388638A (en) * | 2019-08-01 | 2019-10-29 | 河南晋开化工投资控股集团有限责任公司 | A kind of steam thermal energy utilization process in carbon dioxide stripping their urea production |
Non-Patent Citations (2)
| Title |
|---|
| 李春启;: "300kt/a合成氨***节能分析", 化肥工业, no. 02, 28 April 2010 (2010-04-28) * |
| 王森: "在线分析样品处理技术", 30 April 2021, 重庆大学出版社, pages: 23 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100556527C (en) | Compact steam reformer | |
| US5516344A (en) | Fuel cell power plant fuel processing apparatus | |
| US5110559A (en) | Hydrogen generating apparatus | |
| JP5318795B2 (en) | Reactor system | |
| KR100968541B1 (en) | fuel processor of fuel cell system | |
| CA2622270A1 (en) | Method for starting autothermal reformer | |
| CN115010088B (en) | Heat energy utilization mechanism in hydrogen production device | |
| CN105688775A (en) | Reactor with temperature control device | |
| CN205599123U (en) | Utilize id reaction heat to add synthesis reactor of hot feed medium | |
| EA028846B1 (en) | Process for startup and/or shutdown of a plant for preparation of nitric acid | |
| CN116239127A (en) | Synthetic ammonia hot standby process and synthetic tower | |
| JP3921477B2 (en) | Single tube cylindrical reformer and its operating method | |
| CN102211003A (en) | Temperature control device and method for controlling the temperature of a tube reactor | |
| JPS5816933B2 (en) | fluidized bed reactor | |
| JP2019069444A (en) | System and method for carrying out heterogeneously catalyzed gas-phase reactions | |
| KR101194244B1 (en) | Steam reformer | |
| CN102300812A (en) | Apparatus And Method For The Synthesis Of Ammonia | |
| CN114933281A (en) | Natural gas steam reforming furnace based on electromagnetic induction heating | |
| CN208580805U (en) | The thermal control system of pile | |
| JPH01265461A (en) | Phosphoric acid type fuel cell power generation device and its operating method | |
| CN216711970U (en) | Energy-saving device for preparing olefin from synthesis gas | |
| CN218784810U (en) | Methylamine synthesis system | |
| CN113912469A (en) | Energy-saving process for preparing olefin from synthesis gas | |
| CN212595614U (en) | Cold and hot integrated fixed bed reactor | |
| DK180453B1 (en) | Compact burner-reformer unit for a fuel cell system and its use and method of operation |
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 |