CN210632117U - Continuous reaction device - Google Patents
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- CN210632117U CN210632117U CN201921404457.3U CN201921404457U CN210632117U CN 210632117 U CN210632117 U CN 210632117U CN 201921404457 U CN201921404457 U CN 201921404457U CN 210632117 U CN210632117 U CN 210632117U
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Abstract
The utility model relates to a continuous reaction device, include: the gas-liquid separation device comprises a gas blowing-in unit, a feeding unit, a discharging unit and a horizontal hydrogen reduction reactor, wherein the length-diameter ratio of the horizontal hydrogen reduction reactor is 2-10:1, n overflow baffle plates are arranged in a cavity of the horizontal hydrogen reduction reactor, the cavity is divided into n +1 chambers by the overflow baffle plates, n is larger than or equal to 1, a feeding hole and a discharging hole are respectively and independently arranged at two ends of the horizontal hydrogen reduction reactor, at least one gas inlet is arranged at the bottom of the horizontal hydrogen reduction reactor, and at least one gas outlet is arranged at the top of the horizontal hydrogen reduction reactor. The continuous reaction apparatus comprises: the gas blowing-in unit, the feeding unit, the discharging unit and the horizontal hydrogen reduction reactor are used, when the continuous reaction device is used for preparing the chromium oxide through hydrothermal hydrogen reduction, the continuous production of the chromium oxide can be realized, the production efficiency is improved, and the reaction process is energy-saving and environment-friendly.
Description
Technical Field
The utility model belongs to the technical field of chromium compound preparation, a reaction unit is related to, concretely relates to continuous reaction unit.
Background
The chromium oxide is an important inorganic green pigment, a metallurgical raw material, a grinding material and a catalyst, and is widely applied to the fields of fine ceramics, anticorrosion coatings, wave-absorbing materials, green polishing paste, organic catalytic synthesis and the like. At present, the industrial production method of chromium oxide mainly comprises a chromic anhydride thermal decomposition method and a hexavalent chromium salt reduction method.
The thermal decomposition method of chromic anhydride firstly uses sodium dichromate to produce chromic anhydride by concentrated sulfuric acid acidification, and then the chromic anhydride is roasted at high temperature to prepare chromium oxide, which has high cost and serious pollution; the hexavalent chromium salt reduction method takes sulfur or sulfide as a reducing agent, inorganic acid is used for acidification, and the chromium oxide is prepared by dry or wet reduction, so that the production flow is long, and impurity elements such as sulfur and the like are introduced, so that a high-quality product is difficult to obtain.
CN 106745256A discloses a method for preparing chromic oxide by chromate, which takes chromate as raw material, uses carbon-containing reducing gas as reducing agent, reduces at 125-780 ℃ to obtain a reduction product consisting of chromic oxide and carbonate, adds water to dissolve the carbonate in the reduction product, filters, washes,Drying to obtain chromium oxide product, and treating the dissolved solution with CO2Acidifying, separating and recovering carbonate. The method can realize zero discharge of waste water and waste residue in the process, but has high required reduction temperature and high energy consumption.
CN 1999335A discloses a method for preparing chromium oxide powder by hydrothermal reduction of chromate, which takes aqueous solution of chromate as raw material and CO2Gas is an acidifier, and hydrated Cr is obtained by direct reduction under hydrothermal conditions through surfactant treatment2O3Slurry, centrifugal separation and drying to hydrate Cr2O3Preparation of spherical Cr by calcination at different temperatures2O3The method has the advantages that the surface active agent and the organic reducing agent are reflected in the superfine powder, and the produced waste water has great harm to the environment.
Preparation of Cr by hot hydrogen reduction of chromic acid salt water2O3The hydrogen is used as a reducing agent, no by-product and impurity are introduced in the reduction process, and the method has the advantages of short flow, easy control of product quality and the like, and is a clean production method.
The principle of the hot hydrogen reduction of the chromate solution is as follows: the pentavalent chromium in the chromate can be reduced into trivalent chromium by hydrogen under certain pressure, and the hydrogen is converted into OH-Trivalent chromium with OH-CrOOH precipitate is generated in a combined way, and Cr can be obtained by further calcining2O3. Compared with a chromic anhydride thermal decomposition method and a hexavalent chromium salt reduction method, the method for preparing Cr by adopting a chromate hydrothermal hydrogen reduction method2O3High chromium reduction rate and recovery rate, low energy consumption and no three-waste discharge in the technological process, therefore, the chromate hydrogen reduction method can be used for producing Cr2O3The main direction of development.
CN 109354068A discloses chromium oxide and a preparation method thereof, in the method, hexavalent chromium salt solution is added into a reaction device, protective gas is introduced, then the temperature is raised in a closed manner, and hydrogen is continuously introduced to react after the target temperature is reached, so that mixed slurry is obtained; carrying out solid-liquid separation on the mixed slurry to obtain hydroxyl chromium oxide powder; and then calcining the hydroxyl chromium oxide powder to obtain chromium oxide. The reduction rate of chromium can reach 99 percent by regulating and controlling hydrogen and reaction conditionsAs described above, the obtained chromium oxide is high in quality, however, at present, chromate is hydrothermally reduced to produce Cr2O3Corresponding industrial production equipment is not available, equipment such as a vertical high-pressure reaction kettle, a gas lift loop reactor and a pneumatic fluidized tower adopted in a laboratory has the problems of difficult industrial amplification, high manufacturing cost and the like, is not suitable for large-scale production, has high equipment maintenance and maintenance cost, and is difficult to apply in large-scale industrial process.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a continuous reaction device, continuous reaction device's simple structure, gas-liquid is double-phase can be in continuous reaction device's horizontal hydrogen reduction reactor intensive mixing reaction, when being applied to chromic acid salt hydrothermal hydrogen reduction preparation chromic oxide with continuous reaction device, can realize the continuous production of chromic oxide, has improved the reduction rate of production efficiency and sodium chromate, and the reaction process is energy-concerving and environment-protective.
In order to achieve the purpose of the utility model, the utility model adopts the following technical proposal:
the utility model provides a continuous reaction device, continuous reaction device includes: the device comprises a gas blowing-in unit, a feeding unit, a discharging unit and a horizontal hydrogen reduction reactor.
And a feeding hole and a discharging hole are respectively and independently arranged at two ends of the horizontal hydrogen reduction reactor.
And the feeding unit is connected with a feeding hole of the horizontal hydrogen reduction reactor.
And the discharge unit is connected with a discharge hole of the horizontal hydrogen reduction reactor.
And the gas blowing-in unit is connected with a gas inlet of the horizontal hydrogen reduction reactor.
Continuous reaction unit's simple structure can realize the double-phase reaction of gas-liquid in continuous reaction unit's the horizontal hydrogen reduction reactor, and the continuous reaction can improve the efficiency of reaction.
Preferably, the length to diameter ratio of the horizontal hydrogen reduction reactor is 2 to 10:1, and may be, for example, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, n overflow baffles are arranged in the cavity of the horizontal hydrogen reduction reactor, and the overflow baffles divide the cavity into n +1 chambers, where n is a positive integer not less than 1, and may be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 30, and 100, but is not limited to the enumerated values, and other values not enumerated in the range of the enumerated values are also applicable, and a person skilled in the art can select an appropriate number of overflow baffles according to the size of the horizontal hydrogen reduction reactor.
Preferably, the height of the overflow baffle is 1/3-4/5 of the height of the horizontal hydrogen reduction reactor cavity.
Horizontal hydrogen reduction reactor increases the dwell time of feed liquid in horizontal hydrogen reduction reactor through the mode of overflow, through setting up a n overflow plate, makes the reaction go on in n +1 cavity, has improved horizontal hydrogen reduction reactor's reaction efficiency, wherein, n is the positive integer that is not less than 1.
Preferably, the horizontal hydrogen reduction reactor can be provided with n single arch baffles which divide the cavity into n +1 chambers, wherein n is greater than or equal to 2, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc., but not limited to the recited values, and other values not recited in the range of the values are also applicable, and a person skilled in the art can select a proper number of the single arch baffles according to the size of the horizontal hydrogen reduction reactor.
Preferably, the gap chord height of the single arched baffle plate is 1/5-1/3 of the cavity height of the horizontal hydrogen reduction reactor.
The utility model discloses a setting up of single bow-shaped baffling board makes n +1 cavity establish ties, has increased the dwell time of feed liquid in horizontal hydrogen reduction reactor, provides the conversion of feed liquid.
Preferably, the bottom of the chamber is provided with an air inlet independently. The bottom of cavity means n +1 cavity, the bottom of every cavity all is provided with the air inlet independently, n +1 cavity and n +1 air inlet one-to-one promptly, and wherein n is the positive integer, and the technical personnel in the art can rationally select n's numerical value for overflow plate washer or single bow-shaped baffling board according to the mode of cutting apart the cavity.
Preferably, the top of the horizontal hydrogen reduction reactor is provided with at least 1 exhaust port; preferably, when the horizontal hydrogen reduction reactor is divided into n +1 chambers by n overflow baffles, the top of the horizontal hydrogen reduction reactor is provided with 1 exhaust port, and the exhaust port is arranged at the top of the (n + 1) th chamber close to the discharge port end; when the horizontal hydrogen reduction reactor is divided into n +1 chambers by n single arch-shaped baffle plates, n +1 exhaust ports are arranged at the top of the horizontal hydrogen reduction reactor, and the n +1 exhaust ports are respectively and independently arranged at the tops of the n +1 chambers; wherein n is a positive integer, and those skilled in the art can reasonably select the value of n according to the way of dividing the chamber, such as an overflow baffle or a single-arch baffle.
Preferably, the shell of the horizontal hydrogen reduction reactor is provided with a heat preservation device.
Preferably, the insulation means comprises any one or a combination of at least two of a heat trace band, an insulation layer or a jacket, typical but non-limiting combinations include a heat trace band and an insulation layer, an insulation layer and a jacket, a jacket and a heat trace band or a heat trace band, an insulation layer and a jacket.
Preferably, an agitation device is disposed in the chamber.
Be provided with agitating unit do in the cavity n +1 individual cavity is provided with agitating unit respectively independently, and the setting of stirring dress has increased the mixed effect of hydrogen with thick liquids, has further improved reaction efficiency, and wherein, n is the positive integer, and technical staff in the art can be according to the mode of cutting apart the cavity for overflow plate washer or single bow-shaped baffling board, carries out reasonable selection to the numerical value of n.
Preferably, the horizontal hydrogen reduction reactor is provided with any one of a thermometer, a pressure gauge or a liquid level meter or a combination of at least two of them, preferably a thermometer, a pressure gauge and a liquid level meter.
Thermometer, manometer and level gauge are the common thermometer of this field, manometer and level gauge, and the thermometer of suitable range, manometer or level gauge can be selected according to the reaction needs to the skilled person in this field.
Preferably, a gas distributor is arranged at a gas inlet of the horizontal hydrogen reduction reactor. The hydrogen gas flows through the gas inlet and the gas distributor in sequence and then enters the cavity corresponding to the gas inlet.
Preferably, the gas distributor comprises a plate gas distributor and/or a tube gas distributor.
Preferably, the pore size of the gas distributor is 2-1000 μm, and may be, for example, 2 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm.
The utility model discloses select the gas distributor of aperture 2-1000 mu m can make the reaction generate the solid particle in the thick liquids and not fall into gas distributor, can also make hydrogen get into horizontal hydrogen reduction reactor's cavity with the form of microbubble, increase the area of contact of hydrogen and feed liquid, prolong the dwell time of hydrogen in the feed liquid.
Moreover, microbubbles of hydrogen gas generated after the hydrogen gas flows through the gas distributor also have a stirring effect, so that mass transfer in the reaction process can be greatly promoted, and the time of hydrothermal hydrogen reduction reaction is shortened.
Preferably, the gas blowing-in unit comprises a gas blowing-in module, a gas flowmeter and a gas buffer tank which are connected in sequence.
Preferably, the gas bubbling module comprises any one of or a combination of at least two of a gas pump, a high pressure cylinder, or a busbar, and typical but non-limiting combinations include a combination of a gas pump and a high pressure cylinder, a combination of a high pressure cylinder and a busbar, a combination of a gas pump and a busbar, or a combination of a gas pump, a high pressure cylinder, and a busbar, preferably a gas pump.
Preferably, the feeding unit comprises a feed liquid blowing module, a preheating module and a heating module which are connected in sequence.
Preferably, the feed liquid pumping module comprises any one of or a combination of at least two of a diaphragm pump, a plunger pump or a centrifugal pump, and typical but non-limiting combinations include a diaphragm pump and a plunger pump, a plunger pump and a centrifugal pump, a diaphragm pump and a centrifugal pump or a diaphragm pump, a plunger pump and a centrifugal pump, preferably a diaphragm pump.
Preferably, the preheating module is a tubular heat exchanger.
Preferably, the heating module is a tubular heat exchanger; the heat medium of the heating module is heat-conducting oil.
Preferably, the tube heat exchanger comprises any one of a shell-and-tube heat exchanger, a fixed tube plate heat exchanger, a U-tube heat exchanger or a floating head heat exchanger.
Preferably, the discharge unit comprises a discharge pipe and/or a flash tank; the selection of the discharging unit of the utility model is determined by the discharging mode, when the discharging is directly cooled, the discharging unit is a discharging pipeline which is optionally connected with the preheating module, so that the high-temperature slurry after the hydrogen reduction reaction is used as the heat medium of the preheating module; when the material is discharged in a flash evaporation mode, the discharging unit is a flash evaporation tank, and secondary steam generated by flash evaporation of the flash evaporation tank is introduced into the preheating module as a heat medium of the preheating module.
The utility model discloses a high temperature thick liquids or secondary steam after hydrothermal hydrogen reduction reaction have improved thermal utilization efficiency as the hot medium of preheating the module, and thick liquids after preheating flows into heating module to rise to hydrothermal hydrogen reduction reaction required temperature in heating module.
Preferably, the continuous reaction device is also provided with a condenser, and the inlet of the condenser is connected with the exhaust port of the horizontal hydrogen reduction reactor.
And (3) allowing the mixed gas consisting of the hydrogen and the water vapor which are not completely reacted in the horizontal hydrogen reduction reactor to flow into a condenser, condensing the water vapor in the condenser, and recycling the redundant hydrogen for the horizontal hydrogen reduction reactor.
Will the utility model provides a when continuous reaction unit is used for the hot hydrogen reduction of chromic acid salt water to prepare chromium oxide, the preparation process includes following step:
(1) the chromate aqueous solution is heated by the feeding unit and then enters the horizontal hydrogen reduction reactor, and is mixed with the hydrogen entering from the air inlet to carry out reduction reaction in a chamber of the horizontal hydrogen reduction reactor;
(2) feeding the slurry obtained by the reduction reaction in the step (1) into a discharging unit through a discharging port, carrying out solid-liquid separation, and washing, calcining, washing and drying the obtained hydroxyl chromium oxide powder to obtain a chromium oxide product;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, condensed by a condenser and subjected to gas-liquid separation;
the step (2) and the step (3) are not in sequence.
Utilize continuous reaction unit, can make chromate hydrothermal hydrogen reduction preparation chromic oxide be interrupted or go on in succession, preferably go on in succession, wherein, continuous operation can improve production efficiency, has reduced chromic oxide's manufacturing cost.
The utility model discloses in introduced excessive hydrogen in the reduction reaction, the vapor in the solution can be smugglied secretly to hydrogen is discharged by the gas vent, and the vapor in the excessive hydrogen is retrieved after the condensation, and remaining hydrogen can be used for hydrogen reduction reaction again, has improved the utilization ratio of hydrogen.
Preferably, the chromate in step (1) comprises any one or a combination of at least two of sodium chromate, potassium chromate, or lithium chromate, and typical but non-limiting combinations include sodium chromate with potassium chromate, potassium chromate with lithium chromate, sodium chromate with lithium chromate, or sodium chromate, potassium chromate with lithium chromate. Sodium chromate is preferred.
Preferably, the concentration of the chromate aqueous solution in the step (1) is 60-500g/L, such as 60g/L, 100g/L, 150g/L, 200g/L, 250g/L, 300g/L, 350g/L, 400g/L, 450g/L or 500g/L, preferably 200-400 g/L.
Preferably, the temperature of the chromate solution after the temperature rise in the step (1) is 130-250 ℃, such as 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃ or 250 ℃, preferably 180-230 ℃.
Preferably, the total flow rate of the hydrogen in the step (1) is 1 to 1000Nm3H, for example, may be 1Nm3/h、5Nm3/h、10Nm3/h、50Nm3/h、100Nm3/h、150Nm3/h、200Nm3/h、300Nm3/h、400Nm3/h、500Nm3/h、600Nm3/h、700Nm3/h、800Nm3/h、900Nm3H or 1000Nm3/h。
Be provided with n +1 cavity among the horizontal hydrogen reduction reactor, every cavity all independently is provided with the air inlet, and hydrogen evenly distributed is in n +1 air inlet, and wherein n is the positive integer, and technical personnel in the field can be according to the mode of cutting apart the cavity for overflow plate washer or single bow-shaped baffling board, rationally select the numerical value of n.
Preferably, the flow rate of the aqueous chromate solution of step (1) is 1 to 10000Kg/h, and may be, for example, 1Kg/h, 10Kg/h, 50Kg/h, 100Kg/h, 500Kg/h, 1000Kg/h, 2000Kg/h, 3000Kg/h, 4000Kg/h, 5000Kg/h, 6000Kg/h, 7000Kg/h, 8000Kg/h, 9000Kg/h or 10000 Kg/h.
Preferably, the temperature of the reduction reaction in step (1) is 250-350 ℃, such as 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃; a pressure of 7 to 12MPa, for example 7MPa, 8MPa, 9MPa, 10MPa, 11MPa or 12 MPa; the time is 0.5 to 10 hours, and may be, for example, 0.5 hour, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours.
When the hydrothermal hydrogen reduction reaction in the horizontal hydrogen reduction reactor is a discontinuous reaction, the time of the reduction reaction of the utility model is the time of introducing hydrogen; when hydrothermal hydrogen reduction reaction in the horizontal hydrogen reduction reactor is continuous reaction, the time of the reduction reaction is the retention time of chromate aqueous solution in the horizontal hydrogen reduction reactor.
Preferably, the temperature of the slurry in the step (2) after entering the discharging unit is 30-160 ℃ after temperature reduction and pressure reduction, for example, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃ or 160 ℃.
The temperature after the temperature reduction and pressure reduction is related to the discharging mode, when the discharging mode is flash evaporation discharging, the temperature of the residual slurry after the flash evaporation is 160 ℃, for example, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃ or 160 ℃; when the discharging mode is pipeline cooling discharging, the discharging temperature is 30-80 ℃ after heat exchange of the preheating module, for example, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃ or 80 ℃.
As a preferred technical scheme of the preparation process, the preparation process comprises the following steps:
(1)60-500g/L of chromate aqueous solution is heated to 130-250 ℃ by a feeding unit and then enters a horizontal hydrogen reduction reactor to be mixed with hydrogen entering from a gas inlet for reduction reaction, and the total flow of the hydrogen is 1-1000Nm3The flow rate of the chromate aqueous solution is 1 to 10000Kg/h, the temperature of the reduction reaction is 250-350 ℃, the pressure is 7 to 12MPa, and the time is 0.5 to 10 h;
(2) feeding the slurry obtained by the reduction reaction in the step (1) into a discharging unit through a discharging port, performing solid-liquid separation to obtain hydroxyl chromium oxide powder, and sequentially washing, calcining, washing and drying to obtain a chromium oxide product;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, condensed by a condenser and subjected to gas-liquid separation;
the step (2) and the step (3) are not in sequence.
Compared with the prior art, the utility model discloses following beneficial effect has:
(1) the utility model provides a horizontal hydrogen reduction reactor, which has simple structure and low manufacturing cost;
(2) the utility model provides a continuous reaction device, which has simple structure, can realize the continuous production of preparing chromium oxide by hydrothermal hydrogen reduction, improves the production efficiency and the reduction rate of chromate, and further reduces the production cost;
(3) the preheating module of the utility model can preheat the chromate water solution by adopting the high-temperature slurry or the secondary steam of the discharging unit, thereby improving the utilization rate of energy and reducing the energy consumption;
(4) the utility model discloses a setting up of condenser has realized the recycle to unnecessary hydrogen, has improved the utilization ratio of hydrogen.
Drawings
FIG. 1 is a schematic view of the structure of a continuous reaction apparatus provided in example 1;
FIG. 2 is a schematic view of the structure of a continuous reaction apparatus provided in example 2.
Wherein: 11, a gas pump; 12, a gas flow meter; 13, a gas buffer tank; 21, a diaphragm pump; 22, fixing the tube-plate heat exchanger; 23, a U-shaped tube heat exchanger; 31, a feed inlet; 32, a discharge hole; 33, an air inlet; 34, an exhaust port; 35, a plate gas distributor; 361, overflow baffle; 362, single arcuate baffle; 37, a stirring device; 38, a condenser; 41, a flash tank; 42; a discharge pipeline; 5, a thermometer; 6, a pressure gauge; and 7, a liquid level meter.
Detailed Description
The technical solution of the present invention will be further explained by the following embodiments. It should be understood by those skilled in the art that the described embodiments are merely provided to assist in understanding the present invention and should not be construed as specifically limiting the present invention.
The utility model provides a continuous reaction device, wherein, continuous reaction device includes: the device comprises a gas blowing-in unit, a feeding unit, a discharging unit and a horizontal hydrogen reduction reactor.
And a feeding hole and a discharging hole are respectively and independently arranged at two ends of the horizontal hydrogen reduction reactor.
And the feeding unit is connected with a feeding hole of the horizontal hydrogen reduction reactor.
And the discharge unit is connected with a discharge hole of the horizontal hydrogen reduction reactor.
And the gas blowing-in unit is connected with a gas inlet of the horizontal hydrogen reduction reactor.
Further, the length-diameter ratio of the horizontal hydrogen reduction reactor is 2-10: 1.
N overflow baffles or n single arch baffles are arranged in the cavity of the horizontal hydrogen reduction reactor; when n overflow baffles are arranged in the cavity, the cavity is divided into n +1 chambers by the overflow baffles, wherein n is a positive integer not less than 1; when n single-arch baffle plates are arranged in the cavity, the single-arch baffle plates divide the cavity into n +1 cavities, wherein n is a positive integer not less than 2.
Further, when an overflow baffle plate is arranged in the cavity, the height of the overflow baffle plate is 1/3-4/5 of the height of the cavity of the horizontal hydrogen reduction reactor; when the single arch baffle plate is arranged in the cavity, the gap chord height of the single arch baffle plate is 1/5-1/3 of the height of the cavity of the horizontal hydrogen reduction reactor.
Further, the bottom of the chamber is provided with an air inlet independently.
Further, the top of the horizontal hydrogen reduction reactor is provided with at least 1 exhaust port; preferably, when the horizontal hydrogen reduction reactor is divided into n +1 chambers by n overflow baffles, the top of the horizontal hydrogen reduction reactor is provided with 1 exhaust port, and the exhaust port is arranged at the top of the (n + 1) th chamber close to the discharge port end; when the horizontal hydrogen reduction reactor is divided into n +1 chambers by n single arch-shaped baffle plates, n +1 exhaust ports are arranged at the top of the horizontal hydrogen reduction reactor, and the n +1 exhaust ports are respectively and independently arranged at the tops of the n +1 chambers; wherein n is a positive integer, and those skilled in the art can reasonably select the value of n according to the way of dividing the chamber, such as an overflow baffle or a single-arch baffle.
Furthermore, a shell of the horizontal hydrogen reduction reactor is provided with a heat preservation device.
Further, the chambers are respectively and independently provided with stirring devices.
Further, the horizontal hydrogen reduction reactor is provided with any one of a thermometer, a pressure gauge or a liquid level meter or a combination of at least two of the thermometer, the pressure gauge and the liquid level meter.
Further, a gas distributor with the aperture of 2-1000 μm is arranged at the gas inlet of the horizontal hydrogen reduction reactor, and the gas distributor comprises a plate-type gas distributor and/or a tubular gas distributor.
The gas blowing-in unit comprises a gas blowing-in module, a gas flowmeter and a gas buffer tank which are sequentially connected, wherein the gas blowing-in module comprises any one or the combination of at least two of a gas pump, a high-pressure steel cylinder and a busbar.
The feeding unit comprises a feed liquid blowing-in module, a preheating module and a heating module which are sequentially connected, wherein the feed liquid blowing-in module comprises any one or the combination of at least two of a diaphragm pump, a plunger pump or a centrifugal pump.
The preheating module and the heating module are respectively and independently tubular heat exchangers; preferably, the preheating module can be reasonably selected from a fixed tube-plate heat exchanger, a U-shaped tube heat exchanger or a floating head heat exchanger according to the discharging mode of the discharging module; the heating module comprises any one of a shell-and-tube heat exchanger, a fixed tube plate heat exchanger, a U-shaped tube heat exchanger or a floating head heat exchanger, and the heat exchange medium is heat conduction oil.
The discharge unit can select a discharge pipeline or a flash tank according to the discharge mode, the selection of the discharge unit is determined by the discharge mode, when the discharge is directly cooled, the discharge unit is the discharge pipeline, and the discharge pipeline is optionally connected with the preheating module so that the high-temperature slurry after the hydrogen reduction reaction is used as a heat medium of the preheating module; when the material is discharged in a flash evaporation mode, the discharging unit is a flash evaporation tank, and secondary steam generated by flash evaporation of the flash evaporation tank is introduced into the preheating module as a heat medium of the preheating module.
Furthermore, the continuous reaction device is also provided with a condenser, and an inlet of the condenser is connected with an exhaust port of the horizontal hydrogen reduction reactor.
Example 1
The embodiment provides a continuous reaction device, which is schematically shown in fig. 1 and comprises a gas blowing-in unit, a feeding unit, a discharging unit, a condenser 38 and a horizontal hydrogen reduction reactor.
The gas blowing-in unit comprises a gas pump 11, a gas flowmeter 12 and a gas buffer tank 13 which are connected in sequence, and the gas buffer tank 13 is connected with a gas inlet 33 of the horizontal hydrogen reduction reactor.
The discharging unit is a flash tank 41, and a feeding hole 31 of the flash tank 41 is connected with a discharging hole 32 of the horizontal hydrogen reduction reactor.
The condenser 38 is connected with the exhaust port 34 of the horizontal hydrogen reduction reactor, liquid obtained by condensation in the condenser 38 is discharged outside, and hydrogen obtained by recovery in the condenser 38 is recycled for hydrogen reduction reaction.
The feeding unit comprises a diaphragm pump 21, a fixed tube-plate heat exchanger 22 and a U-shaped tube heat exchanger 23 which are connected in sequence. The heat medium of the fixed tube-plate heat exchanger 22 is secondary steam generated by the flash tank 41.
The outlet of the U-shaped tube heat exchanger 23 is connected with the feed inlet 31 of the horizontal hydrogen reduction reactor, and the heat medium of the U-shaped tube heat exchanger 23 is heat conducting oil.
The length-diameter ratio of the horizontal hydrogen reduction reactor is 5:1, a feed inlet 31 and a discharge outlet 32 are respectively and independently arranged at two ends of the horizontal hydrogen reduction reactor, and the horizontal hydrogen reduction reactor is also provided with a thermometer 5, a pressure gauge 6 and a liquid level meter 7.
3 overflow baffles 361 are arranged in the cavity of the horizontal hydrogen reduction reactor, the overflow baffles 361 divide the cavity into 4 chambers, the height of the overflow baffles 361 is 2/3 of the height of the cavity of the horizontal hydrogen reduction reactor, a heat-insulating jacket is arranged on the shell of the horizontal hydrogen reduction reactor, and stirring devices 37 are respectively and independently arranged in the 4 chambers; the bottoms of the 4 chambers are respectively and independently provided with a gas inlet 33, and a plate-type gas distributor 35 with the aperture of 400 mu m is arranged at the gas inlet 33; the top of the chamber of the 4 chambers near the outlet 32 is provided with an outlet 34 connected to a condenser 38.
Example 2
The present embodiment provides a continuous reaction apparatus, which has a schematic structural diagram as shown in fig. 2, and includes a gas blowing-in unit, a feeding unit, a discharging unit, a condenser 38, and a horizontal hydrogen reduction reactor.
The gas blowing-in unit comprises a gas pump 11, a gas flowmeter 12 and a gas buffer tank 13 which are connected in sequence, and the gas buffer tank 13 is connected with a gas inlet 33 of the horizontal hydrogen reduction reactor.
The discharging unit is a discharging pipeline 42, and a feeding hole 31 of the discharging pipeline 42 is connected with a discharging hole 32 of the horizontal hydrogen reduction reactor.
The condenser 38 is connected with the exhaust port 34 of the horizontal hydrogen reduction reactor, liquid obtained by condensation in the condenser 38 is discharged outside, and hydrogen obtained by recovery in the condenser 38 is recycled for hydrogen reduction reaction.
The feeding unit comprises a diaphragm pump 21, a fixed tube-plate heat exchanger 22 and a U-shaped tube heat exchanger 23 which are connected in sequence. The heat medium of the fixed tube-plate heat exchanger 22 is high-temperature slurry conveyed by the discharge pipeline 42.
The outlet of the U-shaped tube heat exchanger 23 is connected with the feed inlet 31 of the horizontal hydrogen reduction reactor, and the heat medium of the U-shaped tube heat exchanger 23 is heat conducting oil.
The length-diameter ratio of the horizontal hydrogen reduction reactor is 5:1, a feed inlet 31 and a discharge outlet 32 are respectively and independently arranged at two ends of the horizontal hydrogen reduction reactor, and the horizontal hydrogen reduction reactor is provided with a thermometer 5, a pressure gauge 6 and a liquid level meter 7.
3 single-arch baffle plates 362 are arranged in the cavity of the horizontal hydrogen reduction reactor, the single-arch baffle plates 362 are arranged at the top end and the bottom end of the horizontal hydrogen reduction reactor at intervals, the cavity is divided into 4 chambers, the chord height of a gap of each single-arch baffle plate 362 is 1/4 of the height of the cavity of the horizontal hydrogen reduction reactor, the shell of the horizontal hydrogen reduction reactor is provided with a heat-insulating jacket, and stirring devices 37 are respectively and independently arranged in the 4 chambers; the bottoms of the 4 chambers are respectively and independently provided with a gas inlet 33, and a plate-type gas distributor 35 with the aperture of 400 mu m is arranged at the gas inlet 33; the top of each of the 4 chambers is independently provided with an exhaust port 34 connected to a condenser 38.
Application example 1
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 400g/L sodium chromate water solution to 230 ℃ through a feeding unit, then feeding the sodium chromate water solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate water solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and carrying out reduction reaction, wherein the total flow of the hydrogen is 500Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 5000Kg/h, the temperature of the reduction reaction is 280 ℃, the pressure is 10MPa, and the time is 3 h;
(2) feeding the slurry obtained in the step (1) through a discharge port into a flash tank, performing solid-liquid separation to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 2
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 100g/L sodium chromate aqueous solution to 250 ℃ through a feeding unit, then feeding the sodium chromate aqueous solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate aqueous solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and carrying out reduction reaction, wherein the total flow of the hydrogen is 300Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 3000Kg/h, the temperature of the reduction reaction is 300 ℃, the pressure is 11MPa, and the time is 3 h;
(2) feeding the slurry obtained in the step (1) through a discharge hole into a flash tank to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying the hydroxyl chromium oxide powder in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 3
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 60g/L sodium chromate water solution to 200 ℃ through a feeding unit, then feeding the sodium chromate water solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate water solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and then carrying out reduction reaction, wherein the total flow of the hydrogen is 100Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 500Kg/h, the temperature of the reduction reaction is 270 ℃, the pressure is 9MPa, and the time is 2 h;
(2) feeding the slurry obtained in the step (1) through a discharge hole into a flash tank to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying the hydroxyl chromium oxide powder in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 4
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 100g/L sodium chromate water solution to 180 ℃ through a feeding unit, then feeding the sodium chromate water solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate water solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and carrying out reduction reaction, wherein the total flow of the hydrogen is 800Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 8000Kg/h, the temperature of the reduction reaction is 250 ℃, the pressure is 12MPa, and the time is 3 h;
(2) feeding the slurry obtained in the step (1) through a discharge port into a flash tank, performing solid-liquid separation to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 5
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 300g/L sodium chromate water solution to 200 ℃ through a feeding unit, then feeding the sodium chromate water solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate water solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and then carrying out reduction reaction, wherein the total flow of the hydrogen is 500Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 5000Kg/h, the temperature of the reduction reaction is 300 ℃, the pressure is 9MPa, and the time is 5 h;
(2) feeding the slurry obtained in the step (1) through a discharge port into a flash tank, performing solid-liquid separation to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 6
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1)200g/L of chromiumThe sodium acid aqueous solution is heated to 180 ℃ by a feeding unit and then enters a horizontal hydrogen reduction reactor, and is mixed with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor for reduction reaction, wherein the total flow of the hydrogen is 200Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 2000Kg/h, the temperature of the reduction reaction is 280 ℃, the pressure is 8MPa, and the time is 7 h;
(2) feeding the slurry obtained in the step (1) through a discharge port into a flash tank, performing solid-liquid separation to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 7
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 400g/L potassium chromate aqueous solution to 230 ℃ through a feeding unit, then feeding the potassium chromate aqueous solution into a horizontal hydrogen reduction reactor, mixing the potassium chromate aqueous solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and carrying out reduction reaction, wherein the total flow of the hydrogen is 200Nm3Hydrogen is evenly distributed at each air inlet, the flow of the potassium chromate aqueous solution is 2000Kg/h, the temperature of the reduction reaction is 320 ℃, the pressure is 10MPa, and the time is 2 h;
(2) feeding the slurry obtained in the step (1) through a discharge port into a flash tank, performing solid-liquid separation to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 8
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 500g/L lithium chromate aqueous solution to 250 ℃ through a feeding unit, then feeding the lithium chromate aqueous solution into a horizontal hydrogen reduction reactor, mixing the lithium chromate aqueous solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and carrying out reduction reaction, wherein the total flow of the hydrogen is 1000Nm3Hydrogen is evenly distributed at each air inlet, the flow of the lithium chromate aqueous solution is 10000Kg/h, the temperature of the reduction reaction is 350 ℃, the pressure is 12MPa, and the time is 0.5 h;
(2) feeding the slurry obtained in the step (1) through a discharge port into a flash tank, performing solid-liquid separation to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 9
The present application example provides a use of the continuous reaction apparatus provided in example 1 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 60g/L sodium chromate water solution to 130 ℃ through a feeding unit, then feeding the sodium chromate water solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate water solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and then carrying out reduction reaction, wherein the total flow of the hydrogen is 1Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 1Kg/h, the temperature of the reduction reaction is 250 ℃, the pressure is 7MPa, and the time is 10 h;
(2) feeding the slurry obtained in the step (1) through a discharge port into a flash tank, performing solid-liquid separation to obtain hydroxyl chromium oxide powder, washing, calcining, washing and drying in sequence to obtain a chromium oxide product, and returning secondary steam obtained by the flash tank as a heat medium to the fixed tube-plate heat exchanger;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 10
The present application example provides a use of the continuous reaction apparatus provided in example 2 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 300g/L sodium chromate water solution to 200 ℃ through a feeding unit, then feeding the sodium chromate water solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate water solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and then carrying out reduction reaction, wherein the total flow of the hydrogen is 500Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 5000Kg/h, the temperature of the reduction reaction is 300 ℃, the pressure is 9MPa, and the time is 5 h;
(2) feeding the slurry obtained by the reduction reaction in the step (1) into a discharging pipeline through a discharging port, discharging after high-temperature feed liquid in the discharging pipeline is used as a heat medium of a fixed tube-plate heat exchanger for heat exchange, performing solid-liquid separation to obtain chromium oxyhydroxide powder, and sequentially washing, calcining, washing and drying to obtain a chromium oxide product;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 11
The present application example provides a use of the continuous reaction apparatus provided in example 2 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 200g/L sodium chromate aqueous solution to 180 ℃ through a feeding unit, then feeding the sodium chromate aqueous solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate aqueous solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and carrying out reduction reaction, wherein the total flow of the hydrogen is 200Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 2000Kg/h, the temperature of the reduction reaction is 280 ℃, the pressure is 8MPa, and the time is 7 h;
(2) feeding the slurry obtained by the reduction reaction in the step (1) into a discharging pipeline through a discharging port, discharging after high-temperature feed liquid in the discharging pipeline is used as a heat medium of a fixed tube-plate heat exchanger for heat exchange, performing solid-liquid separation to obtain chromium oxyhydroxide powder, and sequentially washing, calcining, washing and drying to obtain a chromium oxide product;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 12
The present application example provides a use of the continuous reaction apparatus provided in example 2 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 400g/L sodium chromate aqueous solution to 230 ℃ through a feeding unit, then feeding the sodium chromate aqueous solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate aqueous solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and carrying out reduction reaction, wherein the total flow of the hydrogen is 200Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 2000Kg/h, the temperature of the reduction reaction is 320 ℃, the pressure is 10MPa, and the time is 2 h;
(2) feeding the slurry obtained by the reduction reaction in the step (1) into a discharging pipeline through a discharging port, discharging after high-temperature feed liquid in the discharging pipeline is used as a heat medium of a fixed tube-plate heat exchanger for heat exchange, performing solid-liquid separation to obtain chromium oxyhydroxide powder, and sequentially washing, calcining, washing and drying to obtain a chromium oxide product;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 13
The present application example provides a use of the continuous reaction apparatus provided in example 2 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 500g/L sodium chromate water solution to 250 ℃ through a feeding unit, then feeding the sodium chromate water solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate water solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and carrying out reduction reaction, wherein the total flow of the hydrogen is 1000Nm3Hydrogen is evenly distributed at each air inlet, the flow of the sodium chromate aqueous solution is 10000Kg/h, the temperature of the reduction reaction is 350 ℃, the pressure is 12MPa, and the time is 0.5 h;
(2) feeding the slurry obtained by the reduction reaction in the step (1) into a discharging pipeline through a discharging port, discharging after high-temperature feed liquid in the discharging pipeline is used as a heat medium of a fixed tube-plate heat exchanger for heat exchange, performing solid-liquid separation to obtain chromium oxyhydroxide powder, and sequentially washing, calcining, washing and drying to obtain a chromium oxide product;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
Application example 14
The present application example provides a use of the continuous reaction apparatus provided in example 2 for preparing chromium oxide by hydrothermal hydrogen reduction of chromate, the use including the steps of:
(1) heating 60g/L sodium chromate water solution to 130 ℃ through a feeding unit, then feeding the sodium chromate water solution into a horizontal hydrogen reduction reactor, mixing the sodium chromate water solution with hydrogen entering from an air inlet of the horizontal hydrogen reduction reactor, and then carrying out reduction reaction, wherein the total flow of the hydrogen is 1Nm3H, evenly distributing hydrogen at each air inlet, controlling the flow of sodium chromate solution to be 1Kg/h, controlling the temperature of the reduction reaction to be 250 ℃ and the pressure to be 7MPa, the time is 10 h;
(2) feeding the slurry obtained by the reduction reaction in the step (1) into a discharging pipeline through a discharging port, discharging after high-temperature feed liquid in the discharging pipeline is used as a heat medium of a fixed tube-plate heat exchanger for heat exchange, performing solid-liquid separation to obtain chromium oxyhydroxide powder, and sequentially washing, calcining, washing and drying to obtain a chromium oxide product;
(3) in the reduction reaction in the step (1), excessive hydrogen is discharged from an exhaust port, gas-liquid separation is carried out after condensation by a condenser, and the hydrogen after the gas-liquid separation is reused for the hydrogen reduction reaction;
the step (2) and the step (3) are not in sequence.
And (3) measuring the content of hexavalent chromium in the slurry obtained by the reduction reaction in the step (2) by using an inductively coupled plasma emission spectrometer (ICP), and calculating the reduction rate of chromium according to the content of hexavalent chromium, wherein the reduction rates of chromium in application examples 1-14 are shown in Table 1.
TABLE 1
| Reduction of chromate/%) | |
| Application example 1 | 99.15 |
| Application example 2 | 99.52 |
| Application example 3 | 98.25 |
| Application example 4 | 97.15 |
| Application example 5 | 98.56 |
| Application example 6 | 99.34 |
| Application example 7 | 99.85 |
| Application example 8 | 99.93 |
| Application example 9 | 98.74 |
| Application example 10 | 99.31 |
| Application example 11 | 98.38 |
| Application example 12 | 99.27 |
| Application example 13 | 99.89 |
| Application example 14 | 97.35 |
As can be seen from Table 1, when the continuous reaction device provided by the utility model is used for preparing chromium oxide by hydrothermal hydrogen reduction, the continuous production of chromium oxide can be realized, the reduction rate of chromate is within 97.15-99.93%, and the production efficiency of chromium oxide is high; the preheating module in the continuous reaction device provided by the utility model can preheat the chromate aqueous solution by adopting the high-temperature slurry or the secondary steam of the discharging unit, thereby improving the utilization rate of energy and reducing the energy consumption; and the utility model discloses a setting up of condenser has realized the recycle to unnecessary hydrogen, has improved the utilization ratio of hydrogen.
The applicant states that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and those skilled in the art should understand that any changes or substitutions easily conceivable by those skilled in the art within the technical scope of the present invention are within the protection scope and the disclosure scope of the present invention.
Claims (10)
1. A continuous reaction apparatus, comprising: the device comprises a gas blowing-in unit, a feeding unit, a discharging unit and a horizontal hydrogen reduction reactor;
a feed inlet and a discharge outlet are respectively and independently arranged at two ends of the horizontal hydrogen reduction reactor;
the feeding unit is connected with a feeding hole of the horizontal hydrogen reduction reactor;
the discharge unit is connected with a discharge hole of the horizontal hydrogen reduction reactor;
and the gas blowing-in unit is connected with a gas inlet of the horizontal hydrogen reduction reactor.
2. The continuous reaction device according to claim 1, wherein the length-to-diameter ratio of the horizontal hydrogen reduction reactor is 2 to 10: 1.
3. The continuous reaction device according to claim 2, wherein n overflow baffles are arranged in the cavity of the horizontal hydrogen reduction reactor, and divide the cavity into n +1 chambers, wherein n is greater than or equal to 1;
the height of the overflow baffle is 1/3-4/5 of the height of the cavity of the horizontal hydrogen reduction reactor.
4. The continuous reaction device according to claim 2, wherein n single arch-shaped baffle plates are arranged in the cavity of the horizontal hydrogen reduction reactor, and the cavity is divided into n +1 chambers by the n single arch-shaped baffle plates, wherein n is more than or equal to 2;
the gap chord height of the single arched baffle plate is 1/5-1/3 of the height of the cavity of the horizontal hydrogen reduction reactor.
5. The continuous reaction apparatus according to claim 3 or 4, wherein the bottom of the chamber is independently provided with an air inlet; the top of the horizontal hydrogen reduction reactor is provided with at least 1 exhaust port.
6. The continuous reaction device according to claim 5, wherein the housing of the horizontal hydrogen reduction reactor is provided with a heat preservation device;
the heat preservation device comprises any one or a combination of at least two of a heat tracing band, a heat preservation layer or a jacket.
7. A continuous reaction apparatus according to claim 6, characterised in that stirring means are provided in the chamber.
8. Continuous reaction apparatus according to claim 6 or 7, characterised in that the horizontal hydrogen reduction reactor is provided with any one of a thermometer, a pressure gauge or a level gauge or a combination of at least two thereof.
9. The continuous reaction device according to claim 8, wherein a gas distributor with a pore diameter of 2-1000 μm is arranged at the gas inlet of the horizontal hydrogen reduction reactor;
the gas distributor comprises a plate type gas distributor and/or a tubular type gas distributor.
10. The continuous reaction device according to claim 5, wherein the gas blowing-in unit comprises a gas blowing-in module, a gas flow meter and a gas buffer tank which are connected in sequence;
the gas blowing-in module comprises any one or a combination of at least two of a gas pump, a high-pressure steel cylinder and a busbar;
the feeding unit comprises a feed liquid blowing-in module, a preheating module and a heating module which are connected in sequence;
the feed liquid pumping module comprises any one or a combination of at least two of a diaphragm pump, a plunger pump or a centrifugal pump;
the preheating module and the heating module are respectively and independently tubular heat exchangers; the tube type heat exchanger comprises any one of a fixed tube plate type heat exchanger, a U-shaped tube heat exchanger or a floating head type heat exchanger;
the discharging unit comprises a discharging pipeline and/or a flash tank;
the continuous reaction device is also provided with a condenser, and the inlet of the condenser is connected with the exhaust port of the horizontal hydrogen reduction reactor.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110394138A (en) * | 2019-08-27 | 2019-11-01 | 青海省博鸿化工科技股份有限公司 | A kind of continuous reaction apparatus and application thereof |
| CN112250590A (en) * | 2020-09-30 | 2021-01-22 | 广东石油化工学院 | Method for continuously preparing methyl anthranilate |
| CN114195189A (en) * | 2021-12-21 | 2022-03-18 | 青海省博鸿化工科技股份有限公司 | Preparation process of hydroxyl chromic oxide |
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2019
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110394138A (en) * | 2019-08-27 | 2019-11-01 | 青海省博鸿化工科技股份有限公司 | A kind of continuous reaction apparatus and application thereof |
| CN112250590A (en) * | 2020-09-30 | 2021-01-22 | 广东石油化工学院 | Method for continuously preparing methyl anthranilate |
| CN114195189A (en) * | 2021-12-21 | 2022-03-18 | 青海省博鸿化工科技股份有限公司 | Preparation process of hydroxyl chromic oxide |
| CN114195189B (en) * | 2021-12-21 | 2024-01-02 | 青海省博鸿化工科技股份有限公司 | Preparation process of chromium oxyhydroxide |
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