Tail gas circulation energy-saving ammonia decomposition system supplied to annealing furnace

Abstract

The invention discloses a tail gas circulation energy-saving ammonia decomposition system supplied to an annealing furnace. The tail gas circulation energy-saving ammonia decomposition system comprises an ammonia tank, at least one ammonia decomposition reactor, a cover type annealing furnace and an adsorption system, the ammonia tank is used for providing ammonia gas for the ammonia decomposition reactor; an ammonia decomposition pipeline of a bent structure is arranged in a body of the ammonia decomposition reactor, a combustor is fixed to the body, a combustion outlet of the combustor is communicated with the interior of the body, a smoke outlet is further formed in the body, and the combustor is further communicated with the adsorption system. A decomposed gas outlet of the ammonia decomposition pipeline is connected with an adsorption inlet of the adsorption system, and an adsorption outlet of the adsorption system is communicated with the cover type annealing furnace; the adsorption system comprises a plurality of adsorption columns which are arranged in parallel, and a plurality of valves are arranged among the adsorption columns. According to the annealing system coupled with ammonia decomposition, the requirements of the reduction effect, the heat conductivity, the decarburization capacity, the safety and the like in the annealing process are considered; meanwhile, energy recovery is achieved, electric energy consumption is reduced, and the operation efficiency of the system is improved.

Description

Technical Field

[0001] The invention relates to the technical field of bell-type annealing furnace tail gas treatment equipment, and in particular to a tail gas circulation energy-saving ammonia decomposition system for supplying an annealing furnace. Background Art

[0002] Bell-type furnaces are mostly used for annealing of steel wire, steel pipe, copper strip, copper wire and silicon steel sheet in the metallurgical industry. Traditional bell-type furnaces use nitrogen-hydrogen mixed gas as the protective medium. Compared with nitrogen, hydrogen has the advantages of good thermal conductivity, low density, low dynamic viscosity and strong reducing property. Ammonia decomposition gas is used as the protective gas of the existing bell-type annealing furnace system. There are two main ways to treat the tail gas: one is the tail gas recovery and purification recycling process after the decomposition gas passes through the bell-type annealing furnace, and the tail gas is pre-treated by cooling and spraying for recycling by the bell-type furnace; the other is to use combustion to treat the tail gas. There is still room for improvement in tail gas emissions and energy consumption.

[0003] Chinese patent CN219559260U discloses an SCR denitrification system for hood-type annealing furnace or heating annealing furnace flue gas, including an intake pipe, a mixer, an SCR reactor, a flue gas heater and a premixer. The intake pipe is connected to the inlet end of the mixer, and the intake pipe is also connected to the flue gas heater through a return pipe, and a pyrolysis return fan is provided on the return pipe; the outlet end of the mixer is connected to the SCR reactor through a first connecting pipe, the outlet end of the flue gas heater is connected to the inlet end of the premixer through a second connecting pipe, and the outlet end of the premixer is connected to the mixer. The system heats the flue gas to treat ammonia and adjusts the reactor inlet temperature by using the flue gas, realizing the integration of ammonia production and temperature regulation; however, the system directly heats the flue gas to achieve temperature regulation and ammonia production, which has problems such as high energy consumption and low energy recovery efficiency. Summary of the invention

[0004] The exhaust system containing a bell-type annealing furnace in the prior art has the disadvantages of high energy consumption, low energy recovery efficiency and low system operation efficiency. An energy-saving ammonia decomposition system for supplying an annealing furnace with an exhaust gas circulation has low energy consumption, high recovery rate, good system operation efficiency and good annealing process effect.

[0005] The technical solution adopted by the present invention to solve its technical problems is: an energy-saving ammonia decomposition system for tail gas circulation supplied to an annealing furnace, comprising an ammonia tank, at least one ammonia decomposition reactor, a hood-type annealing furnace and an adsorption system; the ammonia tank is used to provide ammonia gas to the ammonia decomposition reactor; an ammonia decomposition pipeline with a curved structure is arranged in the body of the ammonia decomposition reactor, a burner is fixed on the body, the combustion outlet of the burner is communicated with the interior of the body, a flue gas outlet is also opened on the body, and the burner is also communicated with the adsorption system; the decomposition gas outlet of the ammonia decomposition pipeline is connected to the adsorption inlet of the adsorption system, and the adsorption outlet of the adsorption system is communicated with the hood-type annealing furnace; the adsorption system comprises a plurality of adsorption columns arranged in parallel, a plurality of valves are arranged between the plurality of adsorption columns, and the adsorption states between the plurality of adsorption columns arranged in parallel are different from each other.

[0006] Furthermore, the ammonia decomposition pipeline includes multiple curved pipelines and multiple vertical pipelines. The multiple curved pipelines are stacked in sequence. There is a gap between any two adjacent curved pipelines. Both ends of the curved pipelines are respectively connected to the vertical pipelines; one end of one of the vertical pipelines is an ammonia inlet, and one end of one of the vertical pipelines is a decomposition gas outlet.

[0007] Furthermore, the flue gas outlet is arranged close to the ammonia inlet, the combustion outlet of the burner is arranged close to the decomposition gas outlet, the flue gas outlet and the burner are located on the same side of the body, and there is a gap between the inner wall of the body and the ammonia decomposition pipeline with a curved structure.

[0008] Furthermore, the main body is connected to the electric heater, and a cooling device is provided between the decomposition gas outlet and the adsorption system.

[0009] Furthermore, the interior of the ammonia decomposition pipeline is filled with an ammonia decomposition catalyst, and the ammonia decomposition catalyst is a ruthenium-based catalyst or a nickel-based catalyst.

[0010] Furthermore, it also includes a fan, and an air inlet is opened on the burner, and the air inlet is perpendicular to the installation direction of the burner.

[0011] Furthermore, the adsorption system includes a first adsorption column and a second adsorption column, the first adsorption column and the second adsorption column are arranged in parallel, the upper end of the first adsorption column is connected to the upper end of the second adsorption column by two parallel pipes, and each pipe located at the upper end of the first adsorption column and the upper end of the second adsorption column in parallel is provided with multiple valves; the lower end of the first adsorption column and the second adsorption column are also connected by two parallel pipes, and each pipe located at the lower end of the first adsorption column and the lower end of the second adsorption column in parallel is also provided with multiple valves; the first adsorption column is filled with adsorbent, and the second adsorption column is filled with adsorbent.

[0012] Furthermore, it includes a first ammonia decomposition reactor and a second ammonia decomposition reactor with the same structure, the first ammonia decomposition reactor and the second ammonia decomposition reactor are connected in series, the ammonia inlet of the first ammonia decomposition reactor is connected to the decomposition gas outlet of the second ammonia decomposition reactor, the ammonia inlet of the second ammonia decomposition reactor is connected to the ammonia tank, and the volume of the first ammonia decomposition reactor is greater than that of the second ammonia decomposition reactor.

[0013] Furthermore, it includes a first ammonia decomposition reactor and a second ammonia decomposition reactor with the same structure, the first ammonia decomposition reactor and the second ammonia decomposition reactor are arranged in parallel, the ammonia inlet of the first ammonia decomposition reactor and the ammonia inlet of the second ammonia decomposition reactor are connected to the ammonia tank at the same time, and the decomposition gas outlet of the first ammonia decomposition reactor and the decomposition gas outlet of the second ammonia decomposition reactor are connected to the adsorption system at the same time.

[0014] Furthermore, the bell-type annealing furnace is externally connected to a nitrogen bottle and a hydrogen bottle, a control valve and a flow meter are arranged between the hydrogen bottle and the bell-type annealing furnace, and a control valve and a flow meter are arranged between the nitrogen bottle and the bell-type annealing furnace.

[0015] The energy-saving ammonia decomposition system for supplying an annealing furnace with tail gas circulation described in the present invention reduces heat loss in the gas flow process by connecting a plurality of ammonia decomposition reactors in series or in parallel, and directly attaching a burner to the body of the ammonia decomposition reactor, so that heat can be completely transferred to the ammonia in the ammonia decomposition reactor, thereby promoting a full decomposition reaction of the ammonia; the decomposed hydrogen and nitrogen are adsorbed by an adsorption system connected in parallel with a plurality of adsorption columns and then used for annealing in a bell-type annealing furnace, thereby improving the annealing effect of the annealing furnace, being able to accurately optimize the configuration of different annealing processes and metal materials, and taking into account the reduction effect, thermal conductivity, decarburization ability and safety and other requirements in the annealing process of the bell-type annealing furnace; at the same time, the remaining hydrogen and nitrogen mixed gas after annealing is used for combustion of the burner, and the gas after combustion is used for desorption of the adsorption column and heat absorption of ammonia, respectively, thereby realizing energy recovery and reducing power consumption, thereby improving the operation efficiency of the system; similarly, the air pollution caused by the annealing gas discharged to the air after annealing is also reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a schematic structural diagram of a tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to the present invention; Figure 2This is a schematic structural diagram of another tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to the present invention; Figure 3 It is a structural schematic diagram of an ammonia decomposition reactor of a tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to the present invention; Figure 4 The present invention is a schematic structural diagram of an ammonia decomposition pipeline of an ammonia decomposition reactor of an energy-saving ammonia decomposition system for supplying tail gas to an annealing furnace.

[0018] 1-ammonia tank, 2-ammonia decomposition reactor, 20-main body, 202-flue gas outlet, 21-ammonia decomposition pipeline, 211-ammonia inlet, 212-decomposition gas outlet, 213-bent pipeline, 214-vertical pipeline, 215 heat exchange fins, 22-burner, 221-fuel inlet, 222-combustion outlet, 223-air inlet, 3-hood annealing furnace, 4-blower, 5-adsorption system, 501-adsorption inlet, 502-adsorption outlet, 51-first adsorption column, 52-second adsorption column, 6-cooling device, 2A-first ammonia decomposition reactor, 2B-second ammonia decomposition reactor. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1 to Figure 4 As shown, the energy-saving ammonia decomposition system for tail gas circulation supplying an annealing furnace of the present invention comprises an ammonia tank 1, at least one ammonia decomposition reactor 2, a bell-type annealing furnace 3, a fan 4 and an adsorption system 5; the ammonia tank 1 is used to provide ammonia gas to the ammonia decomposition reactor 2; a curved ammonia decomposition pipeline 21 is arranged in the body 20 of the ammonia decomposition reactor 2, a burner 22 is fixed on the body 20, a combustion outlet 222 of the burner 22 is communicated with the interior of the body 20, and a flue gas outlet 202 is also provided on the body 20; The fan 4 is connected to the burner 22, and the burner 22 is also connected to the adsorption system 5; the decomposition gas outlet 212 of the ammonia decomposition pipeline 21 is connected to the adsorption inlet 501 of the adsorption system 5, and the adsorption outlet 502 of the adsorption system 5 is connected to the hood annealing furnace 3, and the hood annealing furnace 3 is further connected to the combustion inlet of the burner 22; the adsorption system 5 includes a plurality of adsorption columns arranged in parallel, and a plurality of valves are arranged between the plurality of adsorption columns, and the adsorption states between the plurality of adsorption columns arranged in parallel are different from each other.

[0021] exist Figure 3-4 In the embodiment, the ammonia decomposition reactor 2 comprises a body 20, an ammonia decomposition pipeline 21 and a burner 22. The ammonia decomposition pipeline 21 is located inside the body 20. One end of the ammonia decomposition pipeline 21 is an ammonia gas inlet 211, and the other end of the ammonia decomposition pipeline 21 is a decomposition gas outlet 212. The ammonia decomposition pipeline 21 is a curved structure. The ammonia decomposition pipeline 21 comprises a plurality of curved pipelines 213 and a vertical pipeline 214. The plurality of curved pipelines 213 are stacked in sequence. The installation directions of the plurality of curved pipelines 213 are parallel to each other and there is a gap between any two adjacent curved pipelines 213. Both ends of the curved pipeline 213 are respectively connected to different vertical pipelines 214. Figure 4 As shown, one end of the plurality of parallel curved pipes 213 is simultaneously connected to one of the vertical pipes 214, and the other end of the plurality of parallel curved pipes 213 is simultaneously connected to another different vertical pipe 214, and the plurality of vertical pipes 214 are respectively located on both sides of the curved pipe 213, and the installation directions of the plurality of vertical pipes 214 are parallel to each other, and the installation direction of the vertical pipes 214 is perpendicular to the installation direction of the curved pipes 213; specifically, one end of the vertical pipe 214 arranged near the flue gas outlet 202 is the ammonia inlet 211, and one end of the vertical pipe 214 arranged near the combustion outlet 222 is the decomposition gas outlet 212, when ammonia enters one of the vertical pipes 214 through the ammonia inlet 211, ammonia then enters the curved pipe 213 connected thereto through the vertical pipe 214, The ammonia flows in a curved manner in the curved pipe 213 until it enters the vertical pipe 214 connected to the other end of the curved pipe 213. After entering the vertical pipe 214, the ammonia flows along the extension direction of the vertical pipe 214, and then enters another plurality of the curved pipes 213 connected to the vertical pipe 214. Thereafter, the gas flows along the extension directions of different curved pipes 213 and enters the vertical pipe 214 at the other end; thus, the gas continuously flows between the plurality of the curved pipes 213 and the plurality of the vertical pipes 214 until the gas is discharged from the ammonia decomposition reactor 2 through one end of the vertical pipe 214 disposed near the combustion outlet 222, i.e., the decomposition gas outlet 212; by collecting the gas in the vertical pipe 214 and then introducing it into the plurality of the curved pipes 213 respectively, the pressure drop of the gas during the flow process can be reduced, the corresponding energy loss can be reduced, and the energy of the decomposed gas can be increased.

[0022] The burner 22 is directly fixed on the side wall of the body 20, so that the heat seeped from the burner 22 during the combustion process can be fully transferred to the inside of the body 20, reducing the heat loss during the gas flow process and effectively utilizing the energy generated during the operation process; one end of the burner 22 is a combustion outlet 222, and the combustion outlet 222 of the burner 22 is directly connected to the inside of the body 20, and the other end of the burner 22 relative to the combustion outlet 222 is a fuel inlet 221, and the burner 22 is also provided with an air inlet 223, and the air inlet 223 is perpendicular to the installation direction of the burner 22, and the air inlet 223 is connected to the fan 4, and the fan 4 introduces air into the burner 22 through the air inlet 223 for combustion, thereby improving the combustion effect of the burner 22, and the burner 22 can mix the introduced fuel with the air introduced from the fan 4 for combustion, and the tail gas generated after combustion The exhaust gas is discharged through the combustion outlet 222 and enters the interior of the body 20; further, the body 20 is a rectangular structure, and there is a gap between the inner wall of the body 20 and the curved ammonia decomposition pipe 21. After the exhaust gas burned by the burner 22 enters the body 20 through the combustion outlet 222, the exhaust gas after combustion can flow through the curved ammonia decomposition pipe 21 in sequence and fully contact with the ammonia decomposition pipe 21, so as to fully heat the ammonia decomposition pipe 21 with a curved structure, thereby increasing the temperature of the ammonia flowing inside the ammonia decomposition pipe 21 and promoting the endothermic decomposition of ammonia into a mixed gas of hydrogen and nitrogen; in order to improve the decomposition efficiency of ammonia, preferably, the interior of the ammonia decomposition pipe 21 is filled with an ammonia decomposition catalyst, such as a ruthenium-based catalyst or a nickel-based catalyst; the body 20 is also provided with a flue gas outlet 202, and the flue gas outlet 202 is used to discharge the combusted gas after heat exchange from the body 20.

[0023] In order to improve the heat exchange effect between the exhaust gas and ammonia after combustion, increase the heat exchange temperature difference, promote heat conversion and ammonia heat absorption; preferably, the flue gas outlet 202 is arranged close to the ammonia inlet 211, and the combustion outlet 222 of the burner 22 is arranged close to the decomposition gas outlet 212, and the flue gas outlet 202 and the burner 22 are located on the same side of the main body 20; so that the flow direction of the exhaust gas after combustion in the main body 20 is opposite to the flow direction of ammonia in the ammonia decomposition pipeline 21, forming a reverse flow, increasing the heat exchange temperature difference between the exhaust gas and ammonia after combustion, so that the heat between ammonia and the exhaust gas can be fully exchanged, and the endothermic decomposition of ammonia is promoted; more preferably, a plurality of heat exchange fins 215 are vertically installed on the ammonia decomposition pipeline 21, and by installing a plurality of heat exchange fins 215, the turbulence degree of the exhaust gas when flowing through the ammonia decomposition pipeline 21 is increased, and the exhaust gas can heat the ammonia from multiple angles, thereby improving the heating uniformity of the ammonia.

[0024] In order to improve the accurate control of the temperature of the ammonia decomposition process, preferably, the fuel inlet 221 of the burner 22 is provided with a flow meter and a combustion valve, and a temperature sensor is provided in the body 20 of the ammonia decomposition reactor 2. The body 20 is also connected to an electric heater (not shown). The fan 4 adjusts the fan frequency in real time according to the hydrogen flow rate, so as to reduce power consumption and loss. The temperature of the electric heater is automatically adjusted according to the heat generated by the combustion of hydrogen.

[0025] exist Figure 1-2 In the embodiment, the adsorption system 5 includes a first adsorption column 51 and a second adsorption column 52, the first adsorption column 51 and the second adsorption column 52 are arranged in parallel with each other, the upper end of the first adsorption column 51 is connected to the upper end of the second adsorption column 52 through two parallel pipes, and a plurality of valves are arranged on each pipe arranged in parallel at the upper end of the first adsorption column 51 and the upper end of the second adsorption column 52; specifically, a first valve V1 and a seventh valve V7 are arranged on one of the pipes at the upper ends of the first adsorption column 51 and the second adsorption column 52, a sixth valve V6 and a fourth valve V4 are arranged on another pipe at the upper ends of the first adsorption column 51 and the second adsorption column 52, and the adsorption inlet 501 is opened on the pipe provided with the first valve V1 and the seventh valve V7; the lower end of the first adsorption column 51 and the second adsorption column 52 are also connected to each other through two parallel pipes, located at A plurality of valves are also provided on each pipeline which is arranged in parallel with the lower end of the first adsorption column 51 and the lower end of the second adsorption column 52; a third valve V3 and a fifth valve V5 are provided on one of the pipelines located at the lower ends of the first adsorption column 51 and the second adsorption column 52, a second valve V2 and an eighth valve V8 are provided on another pipeline located at the lower ends of the first adsorption column 51 and the second adsorption column 52, and the adsorption outlet 502 is opened on the pipeline provided with the second valve V2 and the second valve V2; wherein, the first adsorption column 51 and the second adsorption column 52 are both filled with an adsorbent, and the adsorbent is a zeolite molecular sieve or a metal organic framework adsorbent (MOFs); by controlling the opening of the valves at different positions, the flow direction of the gas between the first adsorption column 51 and the second adsorption column 52 is adjusted, the adsorption of the gas and the desorption and regeneration of the adsorption column are realized synchronously, and the operation efficiency of the system is improved.

[0026] Among them, the working states of the first adsorption column 51 and the second adsorption column 52 are different. When the first adsorption column 51 is in the adsorption state, the second adsorption column 52 is in the desorption state; when the second adsorption column 52 is in the adsorption state, the first adsorption column 51 is in the desorption state; specifically, the adsorption system 5 includes stage one and stage two. In stage one, the first adsorption column adsorbs and the second adsorption column desorbs: first open the first valve V1 to allow the mixed gas to enter the first adsorption column for adsorption, and then open the second valve V2 to allow the purified gas to flow out of the first adsorption column; at the same time, open the third valve V3 to allow the high-temperature gas to enter the second adsorption column for desorption; then open the fourth valve V4 to allow the desorbed high-temperature gas to flow out of the second adsorption column; in stage two: the first adsorption column desorbs and the second adsorption column adsorbs; first open the seventh valve V7 to allow the mixed gas to enter the second adsorption column for adsorption, and then open the eighth valve V8 to allow the purified gas to The gas flows out from the second adsorption column 52; at the same time, the fifth valve V5 is opened to allow the high-temperature gas to enter the first adsorption column 51 for desorption; and the sixth valve V6 is opened to allow the desorbed gas to flow out from the first adsorption column; in this way, stage one and stage two are continuously cycled to achieve alternating cycle operation of the first adsorption column and the second adsorption column, realize gas purification and separation, improve the purity of hydrogen and nitrogen in the mixed gas, and effectively remove residual impurities in the mixed gas; more specifically, the high-temperature gas is generated after combustion by the burner 22, and the burner 22 is connected to the lower ends of the first adsorption column 51 and the second adsorption column 52 at the same time. A fifth valve V5 is arranged between the burner 22 and the lower end of the first adsorption column 51, and a third valve V3 is arranged between the burner 22 and the lower ends of the second adsorption column 52, so that part of the burned gas can enter the first adsorption column 51 and the second adsorption column 52 for high-temperature desorption respectively.

[0027] like Figure 1The annealing system coupled with ammonia decomposition shown in the figure comprises a first ammonia decomposition reactor 2A and a second ammonia decomposition reactor 2B with the same structure, wherein the first ammonia decomposition reactor 2A and the second ammonia decomposition reactor 2B are connected in series, specifically, the ammonia inlet 211 of the first ammonia decomposition reactor 2A is connected to the decomposition gas outlet 212 of the second ammonia decomposition reactor 2B, and the ammonia inlet 211 of the second ammonia decomposition reactor 2B is connected to the ammonia tank 1; the ammonia introduced from the ammonia tank 1 enters the second ammonia decomposition reactor 2B for a preliminary reaction to generate a mixed gas of hydrogen, nitrogen and a small amount of ammonia; the mixed gas containing a small amount of ammonia after the reaction is introduced into the first ammonia decomposition reactor 2A for further reaction, so that a small amount of ammonia that is not fully reacted in the mixed gas is further reacted to generate a mixed gas of hydrogen and nitrogen; by adopting the connection mode of the first ammonia decomposition reactor 2A and the second ammonia decomposition reactor 2B in series, the staged reaction of ammonia decomposition is realized, which can be Reaction conditions are optimized at different stages. According to the requirements of different reaction stages, catalysts are reasonably arranged and temperatures are adjusted to improve catalyst utilization and ammonia decomposition efficiency; operational flexibility is increased, and by optimizing the size and combination of reactors, energy waste can be reduced and energy utilization efficiency can be improved; more preferably, the volume of the first ammonia decomposition reactor 2A is larger than the volume of the second ammonia decomposition reactor 2B; by preferentially introducing ammonia into the second ammonia decomposition reactor 2B with a smaller volume, the temperature distribution inside the reactor is relatively uniform due to the small volume of the reactor, which is conducive to the rapid transfer and effective utilization of heat and can reach the required reaction temperature more quickly, thereby shortening the start-up time and achieving the initial decomposition of ammonia; the decomposed gas after the initial decomposition is introduced into the first ammonia decomposition reactor 2A with a larger volume for further reaction. Since the first ammonia decomposition reactor 2A has a larger volume, it is conducive to the sufficient residence and reaction of the gas inside the reactor, so that the residual ammonia in the mixed gas can be fully decomposed into hydrogen and nitrogen.

[0028] The decomposition gas outlet 212 of the first ammonia decomposition reactor 2A is connected to the adsorption inlet 501 of the adsorption system 5; in order to improve the adsorption effect of the adsorption system 5, preferably, a cooling device is provided between the decomposition gas outlet 212 of the first ammonia decomposition reactor 2A and the adsorption inlet 501, and the combustion outlet 222 of the burner 22 is connected to the lower end of the first adsorption column 51 in the adsorption system 5 through the fifth valve V5, and the burner 22 The combustion outlet 222 is connected to the lower end of the second adsorption column 52 in the adsorption system 5 through the third valve V3; the cooling device can reduce the temperature of the mixed gas entering the first adsorption column 51 or the second adsorption column 52 to 20-40°C, and the gas with a higher temperature after combustion in the burner 22 enters the first adsorption column 51 or the second adsorption column 52 for desorption of the adsorption column; thereby increasing the adsorption capacity of the adsorbent in the first adsorption column or the second adsorption column during adsorption, and also reducing the adsorption capacity of the adsorbent in the first adsorption column or the second adsorption column during desorption, which is beneficial to the rapid desorption of the adsorbent; thereby improving the overall operating efficiency of the adsorption system; and realizing rapid purification and separation of the gas.

[0029] Furthermore, the adsorption outlet 502 of the adsorption system 5 is directly connected to the bell-type annealing furnace 3, and the mixed gas containing hydrogen and nitrogen after adsorption directly enters the bell-type annealing furnace 3 as the protective gas of the bell-type annealing furnace 3; by using the mixed gas of hydrogen and nitrogen that has been fully decomposed, purified and separated as the bell-type annealing furnace 3, it can effectively prevent the oxidation of metal materials such as cold-rolled thin plates during the annealing process, help to remove oxides on the metal surface, further prevent oxidation, and may improve the finish and quality of the metal surface; at the same time, it also has good deoxidation. Pollution effect; Compared with pure hydrogen and nitrogen as protective gas, the use of fully purified and decomposed hydrogen and nitrogen mixed gas can change the physical properties of the metal to a certain extent, such as hardness, toughness, corrosion resistance, etc., to adapt to different application requirements; In addition, since the thermal conductivity of hydrogen is 7 times that of nitrogen, the heat transfer effect of hydrogen-nitrogen mixed gas is better at the same flow rate, which helps to transfer heat more evenly and quickly during the annealing process, improving annealing efficiency and quality; and compared with the full hydrogen environment, the hydrogen-nitrogen mixed gas reduces the sealing and safety of the furnace. The extremely high requirements of the annealing process are met, while ensuring the annealing effect, the demand for pure hydrogen is reduced, thereby saving costs; at the same time, the reduction effect, thermal conductivity, decarburization ability and safety of the hood-type annealing furnace during the annealing process are taken into account; in order to improve the parameter control of the annealing process of the hood-type annealing furnace 3 and meet the control of the mechanical properties and annealing quality of different materials, preferably, the hood-type annealing furnace 3 is externally connected to a nitrogen bottle and a hydrogen bottle, and the nitrogen bottle and the hydrogen bottle are respectively connected to the hood-type annealing furnace with a control valve and a corresponding flow meter; due to the multiple After the full reaction of the ammonia decomposition reactor 2 and the efficient adsorption of the adsorption system 5, the ratio of hydrogen and nitrogen in the mixed gas introduced into the bell-type annealing furnace 3 is 3:1, and the accuracy of the hydrogen and nitrogen gas ratio is high; the gas ratio test error is reduced, and the annealing parameters of the bell-type annealing furnace 3 can be accurately controlled, and different annealing processes and metal materials can be accurately optimized; more preferably, the inlet of the bell-type annealing furnace 3 is provided with a flow meter and an annealing valve, and the outlet of the bell-type annealing furnace 3 is provided with a pressure transmitter, a pressure sensor and a temperature sensor (not shown).

[0030] In order to effectively utilize the mixed gas after decomposition, improve the gas circulation of the whole system, and also reduce the energy consumption during operation; preferably, the bell-type annealing furnace 3 is connected to the combustion inlet of the burner 22 on the second ammonia decomposition reactor 2B; after the annealing is completed, the bell-type annealing furnace 3 discharges the hydrogen and nitrogen mixed gas in the annealing process from the bell-type annealing furnace 3, directly introduces it into the burner 22 and burns it with the air introduced from the fan 4; provides heating gas as a heat source for the ammonia decomposition reaction in the second ammonia decomposition reactor 2B; achieves the effect of reducing energy consumption and improving the reuse rate of gas in the system; further, the mixed gas of hydrogen and nitrogen is used as fuel for combustion, the generated water vapor has high energy and no greenhouse gas is generated during the combustion process, and the subsequent heating process of the ammonia decomposition reactor and the desorption process of the adsorption system have little impact on the environment, reducing the greenhouse gas emissions during the operation of the system; and the hydrogen discharged after decomposition and purification has high purity and large flow rate, and the heat generated during the combustion process is sufficient, which effectively improves the heating effect of the ammonia decomposition reactor 2 and the high-temperature desorption effect of the adsorption system.

[0031] exist Figure 2 In the embodiment, the first ammonia decomposition reactor 2A and the second ammonia decomposition reactor 2B are arranged in parallel, and the first ammonia decomposition reactor 2A and the second ammonia decomposition reactor 2B have the same structure. The ammonia inlet 211 of the first ammonia decomposition reactor 2A and the ammonia inlet 211 of the second ammonia decomposition reactor 2B are simultaneously connected to the ammonia tank 1; so that ammonia is synchronously decomposed in the first ammonia decomposition reactor 2A and the second ammonia decomposition reactor 2B to generate hydrogen and nitrogen; the generated nitrogen and hydrogen are simultaneously introduced into the adsorption system 5 for purification; specifically, the decomposition gas outlet 212 of the first ammonia decomposition reactor 2A and the decomposition gas outlet 212 of the second ammonia decomposition reactor 2B are simultaneously connected to the adsorption inlet 501 of the adsorption system 5 Specifically, the decomposition gas outlet 212 of the first ammonia decomposition reactor 2A and the decomposition gas outlet 212 of the second ammonia decomposition reactor 2B are simultaneously connected to the cooling device 6, and the cooling device 6 is further connected to the adsorption inlet 501; the mixed gas of hydrogen and nitrogen after decomposition enters the adsorption system 5 composed of two first adsorption columns 51 and second adsorption columns 52 arranged in parallel for adsorption purification to remove residual ammonia in the mixed gas; reduce the influence of ammonia on the annealing effect of the subsequent hood annealing furnace; by adopting two ammonia decomposition reactors arranged in parallel, the operational flexibility of the system is improved, so that the system can operate stably and produce a mixed gas of hydrogen and nitrogen, and it is also beneficial to accurately control and adjust multiple ammonia decomposition reactors respectively.

[0032] The coupled ammonia decomposition annealing system reduces heat loss in the gas flow process by connecting multiple ammonia decomposition reactors in series or in parallel, and directly attaching the burner to the body of the ammonia decomposition reactor, so that the heat can be completely transferred to the ammonia in the ammonia decomposition reactor, and the full decomposition reaction of the ammonia is promoted; the decomposed hydrogen and nitrogen are adsorbed by the adsorption system of multiple adsorption columns in parallel, and then annealed in the bell-type annealing furnace, which improves the annealing effect of the annealing furnace, can accurately optimize the configuration of different annealing processes and metal materials, and takes into account the reduction effect, thermal conductivity, decarburization ability and safety of the bell-type annealing furnace during the annealing process; at the same time, the remaining hydrogen and nitrogen mixed gas after annealing is used for combustion of the burner, and the gas after combustion is used for desorption of the adsorption column and heat absorption of ammonia, respectively, so that energy recovery is achieved, power consumption is reduced, and the operation efficiency of the system is improved.

[0033] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. An energy-saving ammonia decomposition system for tail gas circulation supplying an annealing furnace, comprising an ammonia tank, at least one ammonia decomposition reactor, a bell-type annealing furnace and an adsorption system; characterized in that: The ammonia tank is used to provide ammonia gas for the ammonia decomposition reactor; a curved ammonia decomposition pipeline is arranged in the body of the ammonia decomposition reactor, and a burner is fixed on the body; the combustion outlet of the burner is communicated with the interior of the body, and a flue gas outlet is also opened on the body, and the burner is also communicated with the adsorption system; the decomposition gas outlet of the ammonia decomposition pipeline is connected to the adsorption inlet of the adsorption system, and the adsorption outlet of the adsorption system is communicated with the hood annealing furnace; the adsorption system includes a plurality of adsorption columns arranged in parallel, a plurality of valves are arranged between the plurality of adsorption columns, and the adsorption states between the plurality of adsorption columns arranged in parallel are different from each other.

2. The tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 1 is characterized in that: The ammonia decomposition pipeline comprises a plurality of curved pipelines and a plurality of vertical pipelines. The plurality of curved pipelines are stacked in sequence, and there is a gap between any two adjacent curved pipelines. Both ends of the curved pipelines are respectively connected to the vertical pipelines; one end of one of the vertical pipelines is an ammonia inlet, and one end of one of the vertical pipelines is a decomposition gas outlet.

3. The tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 2 is characterized in that: The flue gas outlet is arranged close to the ammonia inlet, the combustion outlet of the burner is arranged close to the decomposition gas outlet, the flue gas outlet and the burner are located on the same side of the body, and there is a gap between the inner wall of the body and the ammonia decomposition pipeline with a curved structure.

4. The tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 2 is characterized in that: The main body is connected to an electric heater, and a cooling device is arranged between the decomposition gas outlet and the adsorption system.

5. The tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 1 is characterized in that: The ammonia decomposition pipeline is filled with an ammonia decomposition catalyst, and the ammonia decomposition catalyst is a ruthenium-based catalyst or a nickel-based catalyst.

6. The tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 1 is characterized in that: It also includes a fan. The burner is provided with an air inlet, which is perpendicular to the installation direction of the burner.

7. The tail gas recycling and energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 1 is characterized in that: The adsorption system includes a first adsorption column and a second adsorption column, the first adsorption column and the second adsorption column are arranged in parallel, the upper end of the first adsorption column is connected to the upper end of the second adsorption column by two parallel pipes, and a plurality of valves are arranged on each of the pipes arranged in parallel at the upper end of the first adsorption column and the upper end of the second adsorption column; the lower end of the first adsorption column and the second adsorption column are also connected by two parallel pipes, and a plurality of valves are also arranged on each of the pipes arranged in parallel at the lower end of the first adsorption column and the lower end of the second adsorption column; the first adsorption column is filled with adsorbent, and the second adsorption column is filled with adsorbent.

8. The tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 1 is characterized by: The invention comprises a first ammonia decomposition reactor and a second ammonia decomposition reactor of the same structure, wherein the first ammonia decomposition reactor and the second ammonia decomposition reactor are connected in series, an ammonia inlet of the first ammonia decomposition reactor is connected to a decomposition gas outlet of the second ammonia decomposition reactor, an ammonia inlet of the second ammonia decomposition reactor is connected to the ammonia tank, and a volume of the first ammonia decomposition reactor is greater than a volume of the second ammonia decomposition reactor.

9. The tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 1, characterized in that: The invention comprises a first ammonia decomposition reactor and a second ammonia decomposition reactor of the same structure, wherein the first ammonia decomposition reactor and the second ammonia decomposition reactor are arranged in parallel, an ammonia inlet of the first ammonia decomposition reactor and an ammonia inlet of the second ammonia decomposition reactor are connected to the ammonia tank at the same time, and a decomposition gas outlet of the first ammonia decomposition reactor and a decomposition gas outlet of the second ammonia decomposition reactor are connected to an adsorption system at the same time.

10. The tail gas recycling energy-saving ammonia decomposition system for supplying an annealing furnace according to claim 1, characterized in that: The bell-type annealing furnace is externally connected to a nitrogen bottle and a hydrogen bottle, a control valve and a flow meter are arranged between the hydrogen bottle and the bell-type annealing furnace, and a control valve and a flow meter are arranged between the nitrogen bottle and the bell-type annealing furnace.

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