CN112678786A - Diluted nitric acid preparation system and method - Google Patents
Diluted nitric acid preparation system and method Download PDFInfo
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Abstract
The invention relates to a dilute nitric acid preparation system and a method, comprising the following steps: the gas circuit becomes line subassembly, lower flange and deflector etc.. The gas circuit line changing assembly is arranged at the upper part in the reactor and used for changing the trend of a gas circuit path to prevent a gas-liquid mixture from advancing, part of gas-liquid mixture formed by nitrogen monoxide gas generated in the reactor and carrying part of water vapor moves towards the upper part of the reactor, the gas circuit line changing assembly passes through the gas circuit line changing assembly, the gas circuit path of the gas-liquid mixture is changed from the vertical direction to the horizontal direction, part of the gas-liquid mixture starts to be separated, the gas part moves upwards continuously, the liquid part is gathered at the convex part of the lower convex plate and falls back into the reactor under the action of self gravity to continue to participate in reaction, the gas-liquid separation effect is good through the arrangement of the gas circuit line changing assembly, no extra separator is needed to be added for gas-liquid separation, the separation process is closed, and nitrogen monoxide is effectively prevented from being contacted with.
Description
Technical Field
The invention relates to the technical field of dilute nitric acid preparation, in particular to a dilute nitric acid preparation system and method.
Background
Nitric acid is strong acid with strong oxidizing property and corrosiveness, belongs to unitary inorganic strong acid, is one of six inorganic strong acids, and is also an important chemical raw material. Can be used for preparing chemical fertilizers, pesticides, explosives, dyes, salts and the like in industry; in organic chemistry, a mixed solution of concentrated nitric acid and concentrated sulfuric acid is an important nitration reagent, and the industrial application of nitric acid mainly comprises the following steps: as a necessary raw material of nitrate and nitrate, nitric acid is used for preparing a series of nitrate nitrogen fertilizers, such as ammonium nitrate, potassium nitrate and the like; also used for preparing nitrate or nitro-containing explosives; used for refining metal, namely, impure metal is oxidized into nitrate firstly, and then reduced after impurities are removed; adding glycerol into concentrated nitric acid and concentrated sulfuric acid to prepare nitroglycerol. The same industry has different requirements on the concentration of the nitric acid.
Chinese patent No. CN104229761B discloses a dilute nitric acid preparation system and a preparation method thereof, and provides a dilute nitric acid preparation system which can directly prepare dilute nitric acid with a concentration of below 68% by using fuming nitric acid, and simultaneously collect generated nitrogen monoxide to meet social needs. But make the interior reaction of rare nitric acid circulation entering reactor through the rare nitric acid preparation facilities of cycle work, can make the reaction more complete on the one hand, on the other hand can directly prepare the rare nitric acid of different concentrations through the volume that control sprayed into soft water, changed fuming nitric acid and generated the tradition route of the rare nitric acid of concentrated nitric acid reconfiguration, convenient and fast has saved turnover place and turnover time among the traditional handicraft, has also realized the automatic collection of nitric oxide gas, energy utilization has been improved to a great extent.
However, in the above technical solution, the mixed gas of nitric oxide gas and liquid is first separated by the condenser, and the flow path of the mixed gas of nitric oxide gas and liquid is single, so the separation effect is not good, a separator needs to be additionally added for gas-liquid separation, and nitric oxide is easily contacted with air and oxidized into nitrogen dioxide in the separation process, which finally results in impure collected nitric oxide gas and affects the subsequent utilization of the collected nitric oxide.
Disclosure of Invention
Therefore, the invention provides a dilute nitric acid preparation system and a method, which are used for overcoming the problems that in the prior art, because the flow path of the mixed gas of nitric oxide gas and liquid is single, the separation effect is poor, a separator is additionally added for gas-liquid separation, and nitric oxide is easily contacted with air and oxidized into nitrogen dioxide in the separation process, so that the collected nitric oxide gas is not pure, and the subsequent utilization of the collected nitric oxide is influenced.
The invention provides a dilute nitric acid preparation system, which comprises:
the reactor is used for providing a space for preparing dilute nitric acid, a gas path changing line assembly is arranged at the upper part in the reactor and used for changing the trend of a gas path to stop gas-liquid mixture from advancing and providing a space for separating the gas-liquid mixture, the gas path changing line assembly comprises a lower convex plate, a convex part is arranged on the lower convex plate along the vertical direction and towards the bottom of the reactor, two ends of the lower convex plate are fixedly connected to the inner side wall of the reactor, guide plates matched with the lower convex plate are symmetrically and fixedly connected to the lower side of the lower convex plate on the inner side wall of the reactor, the lower convex plate and the guide plates form a guide cavity with a vertical turning horizontal gas path, and the guide cavity is communicated with a nitric oxide collecting tank through a connecting pipe fitting;
the circulating tank is communicated with the liquid outlet end of the reactor and is used for receiving the dilute nitric acid discharged by the reactor;
the heat exchanger is communicated with the circulating tank and is used for dissipating heat of the dilute nitric acid in the circulating process;
and a dilute nitric acid discharge port which is positioned on a pipeline between the circulating tank and the heat exchanger and is used for discharging dilute nitric acid reaching the target concentration.
Preferably, the outside of the connecting pipe fitting is surrounded by a cooling jacket, the connecting pipe fitting comprises an inclined section and a vertical section, one end of the inclined section is communicated with the guide cavity, the other end of the inclined section is connected with one end of the vertical section, and the other end of the vertical section is communicated with the nitric oxide collecting tank.
Preferably, the pipe diameter area of slope section is greater than the pipe diameter area of vertical section, just the inside of connecting the pipe fitting is run through and is provided with a plurality of division boards, and is a plurality of the division board will connect a plurality of gas circuit routes of interior division of pipe fitting, the material of division board is the aluminum alloy.
Preferably, the vertical section with be provided with the connecting pipe between the nitric oxide collecting tank, the connecting pipe with fixed connection between the vertical section, the connecting pipe with can dismantle the connection between the nitric oxide collecting tank, install one-way valve of advancing on the connecting pipe, one-way valve of going out is installed in the exit of nitric oxide collecting tank.
Preferably, the nitric oxide collecting tank is filled with water, and receives nitric oxide in a drainage manner.
Preferably, the lower convex plate is composed of flat plates which are symmetrically and obliquely arranged, the two flat plates face towards one end of the bottom of the reactor and are integrally formed and connected to form a triangular protrusion, the other ends of the two flat plates are fixedly connected with one end of a connecting plate, and the other end of the connecting plate is fixedly connected with the inner side wall of the reactor.
Preferably, the connecting plate is parallel to the guide plate, and the connecting plate is horizontally arranged.
Preferably, an auxiliary separation assembly is fixedly suspended on the inner top wall of the reactor and comprises a fixed rod, one end of the fixed rod is fixedly connected with the inner top wall of the reactor, a spiral material guide plate is fixedly connected onto the fixed rod and used for assisting in separating gas-liquid mixtures, and through holes are uniformly formed in the lower convex plate.
Preferably, the fixing rod is of a cavity structure, and a semiconductor refrigerating piece is installed in the cavity of the fixing rod.
The invention provides a preparation method of dilute nitric acid, which comprises the following steps:
step 1: outputting fuming nitric acid into the reactor, spraying deionized water into the fuming nitric acid from top to bottom in the reactor in a spraying manner, reacting the fuming nitric acid in the reactor with the deionized water to generate nitrogen dioxide gas and dilute nitric acid, and reacting the nitrogen dioxide gas with the deionized water to generate nitric oxide gas and dilute nitric acid;
step 2: in the step 1, the nitric oxide gas generated in the reactor carries part of water vapor to form a gas-liquid mixture, the gas-liquid mixture moves towards the upper part of the reactor, the gas path of the gas-liquid mixture passes through the gas path line changing assembly, the gas path of the gas-liquid mixture is changed from the vertical direction to the horizontal direction, the gas-liquid mixture is stopped by the gas path line changing assembly, the gas-liquid mixture moves along a guide cavity formed by the lower convex plate and the guide plate, at the moment, part of the gas-liquid mixture starts to be separated, the gas part moves upwards continuously, and the liquid part is gathered on the convex part of the lower convex plate and falls back into the reactor under the action of self gravity along the convex part of the lower convex plate;
and step 3: step 2, enabling the gas part to enter the nitric oxide collecting tank along the connecting pipe fitting to be collected, wherein water is filled in the nitric oxide collecting tank, the nitric oxide collecting tank receives nitric oxide in a drainage method, and liquid and gas are continuously separated and fall in the moving process of the connecting pipe fitting;
and 4, step 4: dilute nitric acid obtained by the reaction in the step 1 flows into the circulating tank from the bottom of the reactor, the dilute nitric acid in the circulating tank enters the heat exchanger through a circulating pump, the heat exchanger dissipates heat of the dilute nitric acid in the circulating process, and the dissipated dilute nitric acid flows back to the middle upper part in the reactor through a backflow port to participate in the reaction again, so that the reaction is promoted to be complete;
and 5: according to the required nitric acid concentration, in the reaction of the step 4, spraying of deionized water is reduced or stopped, dilute nitric acid in the circulating tank enters the heat exchanger through a circulating pump for heat exchange, then enters the reactor, water in the dilute nitric acid further reacts with nitrogen dioxide in the step to generate dilute nitric acid, the dilute nitric acid flows into the circulating tank, and therefore the concentration of the dilute nitric acid in the circulating tank is gradually increased until the required concentration of the dilute nitric acid is obtained, and the dilute nitric acid is discharged from a dilute nitric acid discharge port.
Compared with the prior art, the invention has the advantages that the gas circuit line changing assembly is arranged at the upper part in the reactor and is used for changing the trend of a gas circuit path to block the gas-liquid mixture from advancing and provides a space for separating the gas-liquid mixture, the gas circuit line changing assembly comprises a lower convex plate, the lower convex plate is provided with a convex part along the vertical direction and towards the bottom of the reactor, two ends of the lower convex plate are fixedly connected on the inner side wall of the reactor, guide plates matched with the lower convex plate are symmetrically and fixedly connected on the inner side wall of the reactor and positioned at the lower side of the lower convex plate, the lower convex plate and the guide plates form a guide cavity body which is vertically changed into a horizontal gas circuit path, the nitric oxide gas generated in the reactor carries steam to form the gas-liquid mixture to move towards the upper part of the reactor, and the gas-liquid mixture gas circuit path is changed from the vertical direction to, the gas-liquid mixture advances and is blocked by the gas circuit line changing component, the gas-liquid mixture advances along a guide cavity formed by the lower convex plate and the guide plate, at the moment, part of the gas-liquid mixture begins to be separated, the gas part moves upwards continuously, the liquid part is gathered at the convex part of the lower convex plate and falls back into the reactor under the action of self gravity to continue to participate in the reaction, the guide cavity is communicated with the nitric oxide collecting tank through the connecting pipe fitting, the gas part enters the nitric oxide collecting tank along the connecting pipe fitting to be collected, water is filled in the nitric oxide collecting tank, the nitric oxide collecting tank receives the nitric oxide in a drainage method, liquid and gas continuously fall down in the moving process of the connecting pipe fitting, the gas circuit path is changed through the arrangement of the gas circuit line changing component to block the gas-liquid mixture from advancing and provide a space for the gas-liquid mixture separation, the gas-liquid separation effect is good, a separator is not required to be additionally added for gas-liquid separation, and the separation process is closed, so that nitric oxide is effectively prevented from being oxidized into nitrogen dioxide in contact with air in the separation process;
further, the outside of connecting the pipe fitting surrounds and is provided with cooling jacket, connect the pipe fitting and include slope section and vertical section, the one end guide cavity of slope section is linked together, the other end of slope section is connected with the one end of vertical section, the other end and the nitric oxide holding tank of vertical section are linked together, gas-liquid mixture removes the in-process at connecting the pipe fitting, receive cooling jacket's cooling effect, gas-liquid further separation, constantly have liquid and gas separation and whereabouts, the feasible connecting tube spare of slope section and vertical section has the route inflection point, can further increase the gas-liquid separation effect.
Further, the pipe diameter area of slope section is greater than the pipe diameter area of vertical section, and the inside of connecting the pipe fitting is run through and is provided with a plurality of division boards, a plurality of gas circuit routes of internal partitioning that a plurality of division boards will be connected the pipe fitting, the material of division board is the aluminum alloy, aluminum alloy heat conduction is very fast, especially, constitute the division board and increase the gas-liquid separation effect further, the division board will be connected a plurality of gas circuit routes of internal partitioning of pipe fitting, make gas-liquid mixture separately march, can reduce system operating noise to a certain extent.
Further, be provided with the connecting pipe between vertical section and the nitric oxide collecting tank, fixed connection between connecting pipe and the vertical section, can dismantle between connecting pipe and the nitric oxide collecting tank and be connected, install one-way valve of advancing on the connecting pipe, one-way play valve is installed in the exit of nitric oxide collecting tank, the connecting pipe sets up for being connected between convenient vertical section and the nitric oxide collecting tank, the nitric oxide gas gets into in the nitric oxide collecting tank along one-way valve of advancing, the inside of nitric oxide collecting tank is equipped with water, nitric oxide is received with drainage's mode to the nitric oxide collecting tank, water is discharged along one-way play valve simultaneously, nitric oxide and air contact can be avoided to this kind of nitric oxide collecting mode, by the oxidation, thereby guarantee nitric oxide's purity.
Further, the lower flange comprises the flat board that the symmetry slope set up, two flat boards and the one end integrated into one piece towards the reactor bottom connect and constitute triangle-shaped arch, the equal fixed connection connecting plate's of two flat other ends one end, the other end of connecting plate and the inside wall fixed connection of reactor, gas-liquid mixture advances along the direction cavity that lower flange and deflector constitute, part gas-liquid mixture begins the separation this moment, gas portion continues to move up, liquid portion gathers at triangle-shaped bulge, the bulge along lower flange falls back to continue to participate in the reaction in the reactor under self action of gravity.
Furthermore, the connecting plate is parallel to the guide plate, the connecting plate is horizontally arranged, and the connecting plate and the guide plate form a horizontal cavity part of the guide cavity, so that the traveling route of the gas-liquid mixture is changed, and a space is provided for separating the gas-liquid mixture.
Further, it has supplementary separating assembly to hang to fix on the roof in the reactor, supplementary separating assembly includes the dead lever, the one end and the reactor roof fixed connection in of dead lever, fixedly connected with spiral stock guide on the dead lever, the spiral stock guide is used for supplementary gas-liquid mixture separation, the through hole has evenly been seted up to lower flange, supplementary separating assembly further assists the separation gas-liquid mixture, part gas-liquid mixture sees through the part that the flange got into to supplementary separating assembly down, constantly upwards march along spiral stock guide, the in-process of marcing constantly has liquid and gas separation whereabouts under the action of gravity.
Further, the inside of dead lever is the cavity structure, installs the semiconductor refrigeration piece in the cavity of dead lever, through the work of semiconductor refrigeration piece for the dead lever becomes the cold source, and the gas-liquid mixture is constantly upwards marchd the in-process along spiral stock guide, contacts with the cold source constantly, further increases the gas-liquid separation effect.
Drawings
FIG. 1 is a schematic structural diagram of a dilute nitric acid preparation system according to the present invention;
FIG. 2 is a schematic structural diagram of a gas circuit line-changing assembly according to the present invention;
FIG. 3 is a side view of the connecting tube and nitric oxide collection canister of the present invention;
FIG. 4 is a schematic view of a lower cam structure according to the present invention.
In the figure: the device comprises a reactor 1, a gas path changing line component 2, a lower convex plate 201, a guide plate 202, a guide cavity 203, a connecting pipe 3, an inclined section 301, a vertical section 302, a nitric oxide collecting tank 4, a circulating tank 5, a heat exchanger 6, a dilute nitric acid outlet 7, a separation plate 8, a connecting pipe 9, a connecting plate 10, an auxiliary separation component 11, a fixing rod 111 and a spiral material guide plate 112.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.
Referring to fig. 1, which is a schematic structural diagram of a dilute nitric acid preparation system according to the present invention, the dilute nitric acid preparation system includes:
the reactor 1 provides a space for preparing dilute nitric acid, a gas path changing line assembly 2 is arranged at the upper part in the reactor 1, the gas path changing line assembly 2 is used for changing the direction of a gas path to block gas-liquid mixture from advancing, and provides a space for separating the gas-liquid mixture, as shown in fig. 2, the gas path changing line assembly 2 comprises a lower convex plate 201, a convex part is arranged on the lower convex plate 201 along the vertical direction and towards the bottom of the reactor 1, two ends of the lower convex plate 201 are fixedly connected to the inner side wall of the reactor 1, guide plates 202 used in cooperation with the lower convex plate 201 are symmetrically and fixedly connected to the lower side of the lower convex plate 201 on the inner side wall of the reactor 1, the lower convex plate 201 and the guide plates 202 form a guide cavity 203 with a vertical direction-changing horizontal gas path, and the nitrogen oxide gas generated in the reactor 1 carries part of the steam to form the gas-liquid mixture to move towards the upper part of the reactor 1, the gas-liquid mixture gas path is changed from the vertical direction to the horizontal direction through the gas path change line assembly 2, the gas-liquid mixture is stopped by the gas path change line assembly 2, the gas-liquid mixture moves along the guide cavity 203 formed by the lower convex plate 201 and the guide plate 202, at the moment, part of the gas-liquid mixture begins to separate, the gas part moves upwards, the liquid part is gathered at the convex part of the lower convex plate 201 and falls back into the reactor 1 under the action of self gravity along the convex part of the lower convex plate 201 to continue to react, the guide cavity 203 is communicated with the nitric oxide collecting tank 4 through the connecting pipe fitting 3, the gas part enters the nitric oxide collecting tank 4 along the connecting pipe fitting 3 to be collected, water is filled in the nitric oxide collecting tank 4, and the nitric oxide collecting tank 4 receives nitric oxide in a drainage method, during the moving process of the connecting pipe fitting 3, liquid and gas are continuously separated and fall, the gas path direction is changed through the arrangement of the gas path line changing assembly 2 to prevent the gas-liquid mixture from advancing, a space is provided for the gas-liquid mixture separation, the gas-liquid separation effect is good, a separator is not required to be additionally added for gas-liquid separation, and meanwhile, the separation process is closed, so that the nitrogen monoxide is effectively prevented from being oxidized into nitrogen dioxide by contacting with air in the separation process;
a circulating tank 5 which is communicated with the liquid outlet end of the reactor 1 and is used for receiving the dilute nitric acid discharged from the reactor 1;
the heat exchanger 6 is communicated with the circulating tank 5 and used for dissipating heat of the dilute nitric acid in the circulating process, the dilute nitric acid obtained by reaction in the reactor 1 flows into the circulating tank 5 from the bottom of the reactor 1, the dilute nitric acid in the circulating tank 5 enters the heat exchanger 6 through a circulating pump, the heat exchanger 6 dissipates heat of the dilute nitric acid in the circulating process, and the dissipated dilute nitric acid flows back to the middle upper part in the reactor 1 through a backflow port to participate in the reaction again, so that the reaction is promoted to be complete;
and a dilute nitric acid discharge port 7 which is positioned on a pipeline between the circulating tank 5 and the heat exchanger 6 and is used for discharging dilute nitric acid reaching a target concentration, spraying deionized water is reduced or stopped according to the required nitric acid concentration, the dilute nitric acid in the circulating tank 5 enters the heat exchanger 6 through a circulating pump for heat exchange, then enters the reactor 1, water in the dilute nitric acid further reacts with the nitrogen dioxide in the step 1 to generate dilute nitric acid, and the dilute nitric acid flows into the circulating tank 5, so that the concentration of the dilute nitric acid in the circulating tank 5 is gradually increased until the required dilute nitric acid concentration is obtained, and the dilute nitric acid is discharged from the dilute nitric acid discharge port 7.
As shown in fig. 1, specifically, a cooling jacket is disposed around the outside of the connecting pipe 3, the connecting pipe 3 includes an inclined section 301 and a vertical section 302, one end of the inclined section 301 is communicated with the guide cavity 203, the other end of the inclined section 301 is connected with one end of the vertical section 302, the other end of the vertical section 302 is communicated with the nitric oxide collecting tank 4, during the movement of the connecting pipe 3, the gas-liquid mixture is cooled by the cooling jacket, the gas-liquid mixture is further separated, liquid and gas are continuously separated and fall, and the inclined section 301 and the vertical section 302 enable the connecting pipe 3 to have a path inflection point, so that the gas-liquid separation effect can be further increased.
Referring to fig. 3, specifically, the pipe diameter area of the inclined section 301 is larger than that of the vertical section 302, a plurality of partition plates 8 penetrate through the inside of the connecting pipe 3, the plurality of partition plates 8 partition the inside of the connecting pipe 3 into a plurality of gas path paths, the partition plates 8 are made of aluminum alloy, the aluminum alloy has high heat conduction speed, particularly, the partition plates 8 are formed to further increase the gas-liquid separation effect, and the partition plates 8 partition the inside of the connecting pipe 3 into the plurality of gas path paths, so that the gas-liquid mixture separately travels, and the system working noise can be reduced to a certain extent.
Referring to fig. 3, specifically, a connecting pipe 9 is disposed between the vertical section 302 and the nitric oxide collecting tank 4, the connecting pipe 9 is fixedly connected to the vertical section 302, the connecting pipe 9 is detachably connected to the nitric oxide collecting tank 4, a one-way inlet valve is mounted on the connecting pipe 9, a one-way outlet valve is mounted at an outlet of the nitric oxide collecting tank 4, the connecting pipe 9 is disposed to facilitate connection between the vertical section 302 and the nitric oxide collecting tank 4, nitric oxide gas enters the nitric oxide collecting tank 4 along the one-way inlet valve, water is filled in the nitric oxide collecting tank 4, the nitric oxide collecting tank 4 receives nitric oxide in a drainage manner, and the water is discharged along the one-way outlet valve, such a nitric oxide collecting manner can avoid contact between nitric oxide and air, oxidized, thereby ensuring the purity of the nitric oxide.
Referring to fig. 4, specifically, the lower convex plate 201 is composed of flat plates which are symmetrically and obliquely arranged, one end of each of the two flat plates facing the bottom of the reactor 1 is integrally connected to form a triangular protrusion, the other end of each of the two flat plates is fixedly connected to one end of the connecting plate 10, the other end of the connecting plate 10 is fixedly connected to the inner side wall of the reactor 1, the gas-liquid mixture travels along a guide cavity 203 formed by the lower convex plate 201 and the guide plate 202, at this time, part of the gas-liquid mixture starts to separate, the gas part continues to move upwards, the liquid part is gathered at the triangular protrusion, and the liquid part falls back to the reactor 1 along the protrusion of the lower convex plate 201 under the action of self gravity to continue to participate in the reaction.
Referring to fig. 4, specifically, the connecting plate 10 is parallel to the guide plate 202, the connecting plate 10 is horizontally disposed, and the connecting plate 10 and the guide plate 202 form a horizontal cavity portion of the guide cavity 203, so as to change a traveling path of the gas-liquid mixture and provide a space for separating the gas-liquid mixture.
Referring to fig. 1, specifically, an auxiliary separation assembly 11 is fixedly suspended on an inner top wall of the reactor 1, the auxiliary separation assembly 11 includes a fixing rod 111, one end of the fixing rod 111 is fixedly connected to the inner top wall of the reactor 1, a spiral material guide plate 112 is fixedly connected to the fixing rod 111, the spiral material guide plate 112 is used for assisting in separating a gas-liquid mixture, the lower convex plate 201 is uniformly provided with through holes, the auxiliary separation assembly 11 further assists in separating the gas-liquid mixture, a part of the gas-liquid mixture enters the part of the auxiliary separation assembly 11 through the lower convex plate 201, and moves upwards along the spiral material guide plate 112, and liquid and gas continuously fall under the action of gravity during moving.
As shown in fig. 1, specifically, the fixing rod 111 has a cavity structure, a semiconductor refrigeration sheet is installed in the cavity of the fixing rod 111, and the fixing rod 111 becomes a cold source through the operation of the semiconductor refrigeration sheet, and the gas-liquid mixture constantly contacts with the cold source during the process of continuously moving upwards along the spiral material guide plate 112, so as to further increase the gas-liquid separation effect.
Referring to fig. 1, a method for preparing dilute nitric acid includes the following steps:
step 1: outputting fuming nitric acid into the reactor 1, spraying deionized water into the fuming nitric acid from top to bottom in the reactor 1 in a spraying manner, reacting the fuming nitric acid in the reactor 1 with the deionized water to generate nitrogen dioxide gas and dilute nitric acid, and reacting the nitrogen dioxide gas with the deionized water to generate nitric oxide gas and dilute nitric acid;
step 2: in the step 1, the nitric oxide gas generated in the reactor 1 carries part of water vapor to form a gas-liquid mixture, the gas-liquid mixture moves towards the upper part of the reactor 1, the gas-liquid mixture passes through the gas path change line assembly 2, the gas path of the gas-liquid mixture is changed from the vertical direction to the horizontal direction, the gas-liquid mixture is stopped by the gas path change line assembly 2, the gas-liquid mixture moves along the guide cavity 203 formed by the lower convex plate 201 and the guide plate 202, at the moment, part of the gas-liquid mixture starts to be separated, the gas part moves upwards continuously, and the liquid part is gathered on the convex part of the lower convex plate 201 and falls back into the reactor 1 under the action of self gravity along the convex part of the lower convex plate 201 to continuously participate;
and step 3: in the step 2, the gas part enters the nitric oxide collecting tank 4 along the connecting pipe fitting 3 to be collected, water is filled in the nitric oxide collecting tank 4, the nitric oxide collecting tank 4 receives nitric oxide in a drainage method, and liquid and gas are continuously separated and fall in the moving process of the connecting pipe fitting 3;
and 4, step 4: dilute nitric acid obtained by the reaction in the step 1 flows into the circulating tank 5 from the bottom of the reactor 1, dilute nitric acid in the circulating tank 5 enters the heat exchanger 6 through a circulating pump, the heat exchanger 6 dissipates heat of the dilute nitric acid in the circulating process, and the dissipated dilute nitric acid flows back to the middle upper part in the reactor 1 through a backflow port to participate in the reaction again, so that the reaction is promoted to be complete;
and 5: according to the required nitric acid concentration, in the reaction of the step 4, spraying of deionized water is reduced or stopped, dilute nitric acid in the circulating tank 5 enters the heat exchanger 6 through a circulating pump for heat exchange, then enters the reactor 1, water in the dilute nitric acid further reacts with nitrogen dioxide in the step 1 to generate dilute nitric acid, the dilute nitric acid flows into the circulating tank 5, and therefore the concentration of the dilute nitric acid in the circulating tank 5 is gradually increased until the required dilute nitric acid concentration is obtained, and the dilute nitric acid is discharged from a dilute nitric acid discharge port 7.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention; various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A dilute nitric acid preparation system, comprising: the reactor (1) provides a space for preparing dilute nitric acid, a gas circuit transformation line assembly (2) is arranged on the upper portion in the reactor (1), the gas circuit transformation line assembly (2) is used for changing the trend of a gas circuit path to block a gas-liquid mixture from advancing, the gas circuit transformation line assembly (2) provides a space for separating the gas-liquid mixture, the gas circuit transformation line assembly (2) comprises a lower convex plate (201), the lower convex plate (201) is arranged along the vertical direction and faces the bottom of the reactor (1), two ends of the lower convex plate (201) are fixedly connected to the inner side wall of the reactor (1), a guide plate (202) matched with the lower convex plate (201) and used is symmetrically and fixedly connected to the lower side of the inner side wall of the reactor (1), and the lower convex plate (201) and the guide plate (202) form a guide cavity (203) with a vertical direction-changing horizontal gas circuit path, the guide cavity (203) is communicated with the nitric oxide collecting tank (4) through a connecting pipe fitting (3);
a circulating tank (5) which is communicated with the liquid outlet end of the reactor (1) and is used for receiving the dilute nitric acid discharged from the reactor (1);
the heat exchanger (6) is communicated with the circulating tank (5) and is used for dissipating heat of the dilute nitric acid in the circulating process;
and a dilute nitric acid discharge port (7) which is positioned on a pipeline between the circulating tank (5) and the heat exchanger (6) and is used for discharging dilute nitric acid reaching the target concentration.
2. The dilute nitric acid preparation system according to claim 1, wherein a cooling jacket is arranged around the outside of the connecting pipe (3), the connecting pipe (3) comprises an inclined section (301) and a vertical section (302), one end of the inclined section (301) is communicated with the guide cavity (203), the other end of the inclined section (301) is connected with one end of the vertical section (302), and the other end of the vertical section (302) is communicated with the nitric oxide collecting tank (4).
3. The dilute nitric acid preparation system according to claim 2, wherein the pipe diameter area of the inclined section (301) is larger than that of the vertical section (302), a plurality of partition plates (8) penetrate through the inside of the connecting pipe (3), the inside of the connecting pipe (3) is divided into a plurality of gas path paths by the plurality of partition plates (8), and the partition plates (8) are made of aluminum alloy.
4. The dilute nitric acid preparation system according to claim 2, wherein a connecting pipe (9) is arranged between the vertical section (302) and the nitric oxide collecting tank (4), the connecting pipe (9) is fixedly connected with the vertical section (302), the connecting pipe (9) is detachably connected with the nitric oxide collecting tank (4), a one-way inlet valve is installed on the connecting pipe (9), and a one-way outlet valve is installed at an outlet of the nitric oxide collecting tank (4).
5. A dilute nitric acid preparation system according to claim 4, wherein said nitric oxide collecting tank (4) is filled with water, and said nitric oxide collecting tank (4) receives nitric oxide by draining.
6. The dilute nitric acid preparation system of claim 1, wherein the lower convex plate (201) is composed of flat plates which are symmetrically and obliquely arranged, one ends of the two flat plates facing the bottom of the reactor (1) are integrally formed and connected to form a triangular protrusion, the other ends of the two flat plates are fixedly connected with one end of a connecting plate (10), and the other end of the connecting plate (10) is fixedly connected with the inner side wall of the reactor (1).
7. A dilute nitric acid preparation system according to claim 6, wherein said connecting plate (10) is parallel to said guide plate (202), and said connecting plate (10) is horizontally disposed.
8. The dilute nitric acid preparation system according to any one of claims 1 to 7, wherein an auxiliary separation assembly (11) is fixedly suspended on the inner top wall of the reactor (1), the auxiliary separation assembly (11) comprises a fixing rod (111), one end of the fixing rod (111) is fixedly connected with the inner top wall of the reactor (1), a spiral guide plate (112) is fixedly connected to the fixing rod (111), the spiral guide plate (112) is used for assisting in separating a gas-liquid mixture, and the lower convex plate (201) is uniformly provided with through holes.
9. The dilute nitric acid preparation system of claim 8, wherein the fixing rod (111) is internally provided with a cavity structure, and a semiconductor refrigerating sheet is arranged in the cavity of the fixing rod (111).
10. A preparation method of dilute nitric acid is characterized by comprising the following steps:
step 1: outputting fuming nitric acid into the reactor (1), spraying deionized water into the fuming nitric acid from top to bottom in the reactor (1) in a spraying mode, reacting the fuming nitric acid in the reactor (1) with the deionized water to generate nitrogen dioxide gas and dilute nitric acid, and reacting the nitrogen dioxide gas with the deionized water to generate nitric oxide gas and dilute nitric acid;
step 2: in the step 1, the nitric oxide gas generated in the reactor (1) carries part of water vapor to form a gas-liquid mixture, the gas-liquid mixture moves towards the upper part of the reactor (1), the gas-liquid mixture passes through the gas path changing line assembly (2), the gas path of the gas-liquid mixture is changed from the vertical direction to the horizontal direction, the gas-liquid mixture advances and is blocked by the gas path changing line assembly (2), the gas-liquid mixture advances along a guide cavity (203) formed by the lower convex plate (201) and the guide plate (202), at the moment, part of the gas-liquid mixture starts to be separated, the gas part moves upwards continuously, the liquid part is gathered on the convex part of the lower convex plate (201), and falls back into the reactor (1) under the action of self gravity along the convex part of the lower convex plate (201) to continue to react;
and step 3: in the step 2, the gas part enters the nitric oxide collecting tank (4) along the connecting pipe fitting (3) to be collected, water is filled in the nitric oxide collecting tank (4), the nitric oxide collecting tank (4) receives nitric oxide in a drainage method, and liquid and gas are continuously separated and fall off in the moving process of the connecting pipe fitting (3) of the gas-liquid mixture;
and 4, step 4: dilute nitric acid obtained by the reaction in the step 1 flows into the circulating tank (5) from the bottom of the reactor (1), dilute nitric acid in the circulating tank (5) enters the heat exchanger (6) through a circulating pump, the heat exchanger (6) dissipates heat of the dilute nitric acid in the circulating process, and the dissipated dilute nitric acid flows back to the middle upper part in the reactor (1) through a backflow port to participate in the reaction again, so that the reaction is promoted to be complete;
and 5: according to the required nitric acid concentration, in the reaction of the step 4, spraying of deionized water is reduced or stopped, dilute nitric acid in the circulating tank (5) enters the heat exchanger (6) through a circulating pump for heat exchange, then enters the reactor (1), water in the dilute nitric acid further reacts with nitrogen dioxide in the step 1 to generate dilute nitric acid, the dilute nitric acid flows into the circulating tank (5), so that the concentration of the dilute nitric acid in the circulating tank (5) is gradually increased until the required concentration of the dilute nitric acid is obtained, and the dilute nitric acid is discharged from a dilute nitric acid discharge port (7).
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| US5670127A (en) * | 1995-09-26 | 1997-09-23 | The Boc Group, Inc. | Process for the manufacture of nitric oxide |
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| JP2014189471A (en) * | 2013-03-28 | 2014-10-06 | Sumitomo Seika Chem Co Ltd | Apparatus for recovering nitrogen monoxide gas |
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