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    • 专利摘要:
    The present invention provides a device and a process for the catalytic oxidation of magnesium sulfite, a cobalt nitrate / ZSM-5 molecular sieve catalyst, and a process for the preparation thereof. A magnesium sulfite raw material is pretreated using a preparation box (1), a catalytic oxidation reaction is carried out using a reaction box (2), a slurry of magnesium sulfate after catalytic oxidation is concentrated in Using an evaporator (3), the concentrated slurry is cooled and crystallized using a cooling crystallization box (4). The solid obtained is directly used as a product for the evacuation, and the remaining slurry returns to the evaporator (3) for continuous concentration.
    公开号:BE1027253B1
    申请号:E20195730
    申请日:2019-10-21
    公开日:2020-11-30
    发明作者:Lidong Wang；Su Lu；Yongliang Ma
    申请人:North China Electric Power Univ Baoding；Univ Tsinghua；
    IPC主号:
    专利说明:

    Device and process for the catalytic oxidation of magnesium sulfite, cobalt nitrate catalyst / zsm-5 molecular sieve and process for the preparation thereof Field of the invention The present invention relates to the technical field of gas desulfurization. flue, and in particular a device and a method for the catalytic oxidation of magnesium sulfite, a cobalt nitrate / molecular sieve catalyst ZSM-5 and a method for the preparation thereof.
    STATE OF THE ART A magnesium process desulfurization technology has the advantages of good desulfurization effect, low cost of operation and maintenance, and the like, and is currently widely used by coal fired boilers.
    However, desulfurization by a magnesium process generates a large amount of magnesium sulfite by-product which needs to be oxidized to magnesium sulfate before the by-product can be recycled.
    The recovery of the existing magnesium sulphite is carried out mainly by adopting a method of concentration by forced non-catalytic oxidation and evaporative crystallization of magnesium sulphate.
    Due to the low rate of oxidation, the area occupied by the oxidation is large, the energy consumption of evaporation is large, the cost of recovery is high, and continuous production cannot be achieved.
    It has also been reported that a homogeneous catalytic oxidation process has been attempted, i.e., transition metal ions are directly added to a slurry of magnesium sulfite for catalytic oxidation, but this process has the problems characterized. in that it is difficult to recover the transition metal ions, heavy metal ion contamination occurs, and the running cost is high.
    Summary of the Invention In view of the foregoing, an object of the present invention is to provide a device and method for the catalytic oxidation of magnesium sulfite, a cobalt nitrate / ZSM-5 molecular sieve catalyst and a ZSM-5 molecular sieve catalyst. method of preparation thereof.
    The device provided by the present invention can achieve continuous catalytic oxidation of magnesium sulfite and crystallization recovery of magnesium sulfate, and has high catalytic oxidation efficiency and does not cause environmental pollution.
    To achieve the above object, the present invention provides the following technical solutions.
    The present invention provides a device for the catalytic oxidation of magnesium sulfite, including a preparation box; a reaction box having an inlet communicating with an outlet of the preparation box, the reaction box including therein an aeration device and a catalyst layer, and a catalyst of the catalyst layer being a nitrate catalyst cobalt / ZSM-5 molecular sieve; an evaporator having an inlet communicating with an outlet of the reaction box; and a cooling crystallization box having an inlet communicating with an outlet of the evaporator, wherein the cooling crystallization box includes a solid discharge port and a liquid discharge port, and the discharge port of liquid communicates with the inlet of the evaporator.
    Preferably, the preparation box is provided inside with a sampling pump, an agitator, a chemical dispenser and a filter; the evaporator is provided inside with an air suction device, a heater and a stirrer; and the cooling crystallization box is internally provided with a cooling device and a rotary filter.
    The present invention further provides a process for the catalytic oxidation of magnesium sulfite using the device described above, including the following steps:
    step (1): mixing a raw material of magnesium sulfite with water in a preparation box to obtain a thick suspension of magnesium sulfite; step (2): contacting the slurry of magnesium sulfite with a catalyst in a reaction box for an oxidation reaction under aeration conditions to obtain a slurry of magnesium sulfate; step (3): concentration of the slurry of magnesium sulfate in an evaporator to obtain a concentrated slurry of magnesium sulfate; and step (4): cooling the slurry of magnesium sulfate in a crystallization box by cooling for crystallization to obtain a solid of magnesium sulfate and a remaining slurry of magnesium sulfate, and returning the slurry of magnesium sulfate remaining to the evaporator for a new concentration.
    Preferably, the mass concentration of the slurry of magnesium sulphite in step (1) is 40 to 60%. Preferably, the ratio of the mass of the catalyst in step (2) to the volume of the slurry of magnesium sulphite is 20 to 100 g / l. Preferably, the aeration gas in step (2) is air; and the temperature of the oxidation reaction is 40-70 ° C.
    Preferably, the temperature of the concentration in step (3) is 40-70 ° C, the volume of the concentrated slurry of magnesium sulfate is 40-70% that of the slurry of magnesium sulfate before concentration; and the temperature of the cooling crystallization in step (4) is 10 to 25 ° C, and the time is 3 to 8 hours.
    The present invention further provides a ZSM-5 molecular sieve / cobalt nitrate catalyst, including a ZSM-5 molecular sieve and cobalt nitrate loaded into the ZSM-5 molecular sieve, where the mass loading capacity of cobalt nitrate in the cobalt nitrate catalyst / ZSM-5 molecular sieve is 2 to 15%.
    The present invention further provides a process for the preparation of the cobalt nitrate / ZSM-5 molecular sieve catalyst described above, including the following step: step (1): mixing a ZSM-5 molecular sieve with a ZSM-5 molecular sieve. solution of cobalt nitrate for ion exchange to obtain a catalyst precursor; and step (2): calcining the catalyst precursor to obtain the cobalt nitrate / ZSM-5 molecular sieve catalyst. Preferably, the molar concentration of the cobalt nitrate solution is 0.1 to 0.3 mol / l; and the ratio of the mass of the ZSM-5 molecular sieve to the volume of the cobalt nitrate solution is 2 to 10 g / 100 ml.
    The present invention provides a device for the catalytic oxidation of magnesium sulfite, including a preparation box; a reaction box having an inlet communicating with an outlet of the preparation box, the reaction box including an aeration device and a catalyst layer; an evaporator having an inlet communicating with an outlet of the reaction box; and a cooling crystallization box having an inlet communicating with an outlet of the evaporator, wherein the cooling crystallization box includes a solid discharge port and a liquid discharge port, and the discharge port of liquid communicates with the inlet of the evaporator.
    In the present invention, a raw material of magnesium sulphite is pretreated using the preparation box, a catalytic oxidation reaction is carried out using the reaction box, a slurry of magnesium sulphate after catalytic oxidation is concentrated using evaporator, the concentrated slurry is cooled and crystallized using the cooling crystallization box, the obtained solid is directly used as a product for evacuation, and the remaining slurry returns to the evaporator for continuous concentration .
    The device provided by the present invention is a continuous reaction device, can realize continuous catalytic oxidation of magnesium sulfite, and has high production efficiency and low cost, and the whole catalytic oxidation process is free of waste. residuals and liquid waste.
    The ZSM-5 cobalt nitrate / molecular sieve catalyst used in the device provided by the present invention is a solid catalyst, which has high catalytic speed and long service life, and can avoid pollution caused by homogeneous catalyst. The present invention provides a process for the preparation of the ZSM-5 cobalt nitrate / molecular sieve catalyst. The process is simple and convenient and industrial production is easily achieved, and the obtained ZSM-5 molecular sieve / cobalt nitrate catalyst has a high catalytic rate when used to catalyze the oxidation of magnesium sulfite. Brief Description of the Drawings Figure 1 is a structural schematic view of a device for the catalytic oxidation of magnesium sulfite according to the present invention, where 1. preparation box, 2. reaction box, 3. evaporator, 4. box crystallization by cooling, 5. aeration device, 6. catalyst layer.
    Detailed Description The present invention provides a device for the catalytic oxidation of magnesium sulphite, as illustrated in Figure 1, including a preparation box 1; a reaction box 2 having an inlet communicating with an outlet of the preparation box, the reaction box including an aeration device 5 and a catalyst layer 6, and a catalyst of the catalyst layer being a nitrate catalyst of cobalt / ZSM-5 molecular sieve; an evaporator 3 having an inlet communicating with an outlet of the reaction box; and a cooling crystallization box 4 having an inlet communicating with an outlet of the evaporator, wherein the cooling crystallization box includes a solid discharge port and a liquid discharge port, and the port d. liquid evacuation communicates with the inlet of the evaporator. The device provided by the present invention includes a preparation box. In the present invention, the preparation box is preferably provided with a sampling pump, an agitator, a chemical dispenser, a filter, and an outlet for impurities.
    In the present invention, the sampling pump is intended to input a raw material consisting of a thick suspension of magnesium sulfite and water; the agitator is configured to agitate the slurry of magnesium sulfite; the chemical dispenser is configured to add a pH regulator to the slurry to adjust the pH of the slurry; the filter is configured to filter the slurry of magnesium sulphite to remove solid impurities in the slurry; the outlet for the impurities is configured to discharge the solid impurities in the slurry, and the solid impurities are specifically impurities such as stones and leaves.
    The present invention does not have particular requirements for the specific types of the sampling pump, agitator, chemical dispenser and filter, and the above-mentioned devices well known to those skilled in the art. can be used.
    In the present invention, the sampling pump is preferably located at the entrance to the preparation box.
    The present invention does not have any particular requirements for the installation positions of the agitator, the chemical dispenser and the filter in the preparation box, and the installation positions well known to those skilled in the art can. be used and it should be ensured that the devices play the corresponding roles.
    The device provided by the present invention includes a reaction box having an inlet communicating with an outlet of the preparation box; the reaction box includes an aeration device and a catalyst layer, a catalyst of the catalyst layer is a ZSM-5 cobalt nitrate / molecular friend catalyst; the ZSM-5 cobalt nitrate / molecular sieve catalyst includes a ZSM-5 molecular sieve and cobalt nitrate loaded into the ZSM-5 molecular sieve; and the mass loading capacity of cobalt nitrate in the cobalt nitrate / ZSM-5 molecular sieve catalyst is 2 to 15%, preferably 3 to 10%. The solid catalyst is adopted in the present invention, which can reduce the loss of the catalyst and avoid the pollution by an oxidation product (magnesium sulfate) caused by the loss of the catalyst. In the present invention, the aeration device is preferably an aeration pipe, and the aeration pipe is provided with rows of small holes, and bubbles are generated after ventilation. In the present invention, the aeration device is preferably disposed at the bottom of the reaction box, and the catalyst layer is preferably located in the center of the reaction box. In the present invention, the reaction box is further provided with a circulation pump and a filter, where the circulation pump allows the slurry to exchange vertically in the reaction box, the concentration of each substance in the reaction box is kept uniform, it is ensured that the magnesium sulfate is fully in contact with the catalyst and is fully oxidized; and the filter is configured to separate the magnesium sulphite from the magnesium sulphate using the difference between the solubility of the magnesium sulphite and the solubility of the magnesium sulphate.
    The device provided by the present invention includes an evaporator having an inlet communicating with an outlet of the reaction box. In the present invention, the slurry of magnesium sulfate is subjected to concentration by evaporation by the evaporator. In the present invention, the evaporator is preferably provided with an air suction device, a heater and a stirrer. In the present invention, the air suction device is configured to create a vacuum in the evaporator, the heater is configured to heat the slurry of magnesium sulfate, and the agitator is configured to agitate the slurry. thick. In the present invention, the heater is preferably an automatic electric heater. The present invention has no special requirements for specific types and models of the air suction device and the agitator, and the air suction device and model well known to those skilled in the art can be. used. The present invention has no special requirements for the installation positions of the air suction device, the heater and the agitator in the evaporator, and the installation positions well known to those skilled in the art. can be used and it is ensured that the devices play the corresponding roles.
    The device provided by the present invention includes a cooling crystallization box having an inlet communicating with an outlet of the evaporator, wherein the cooling crystallization box includes a solid discharge port and a liquid discharge port, and the liquid discharge port communicates with the inlet of the evaporator.
    In the present invention, the cooling crystallization box is preferably provided internally with a cooling device and a rotary filter.
    The present invention has no special requirements for the specific type and model of the cooling device and the rotary filter, and a cooling device and a rotary filter which are well known in the art can be used.
    In the present invention, the cooling device cools the slurry of magnesium sulfate to achieve cooling and crystallization of the slurry of magnesium sulfate; the rotary filter is configured to perform solid-liquid separation on the crystallized slurry of magnesium sulfate, the resulting magnesium sulfate solid is discharged from a solid discharge port, and the remaining liquid returns to the 'evaporator to continue to be evaporated and concentrated.
    The device provided by the present invention preferably further includes slurry discharge pumps, and the slurry discharge pumps are preferably located at the preparation box, the reaction box, the slurry. outlet of the evaporator, and of the liquid outlet of the cooling crystallization box.
    In the present invention, the slurry is gently transported through the liquid discharge pump.
    The present invention does not have any special requirements for the specific type and model of the liquid discharge pump, and a liquid discharge pump well known to those skilled in the art can be used.
    The present invention provides a process for the catalytic oxidation of magnesium sulphite to magnesium sulphate using the device mentioned above, including the following steps:
    step (1): mixing a raw material of magnesium sulfite with water in a preparation box to obtain a thick suspension of magnesium sulfite; step (2): contacting the slurry of magnesium sulfite with a catalyst in a reaction box for an oxidation reaction under aeration conditions to obtain a slurry of magnesium sulfate; step (3): concentration of the slurry of magnesium sulfate in an evaporator to obtain a concentrated slurry of magnesium sulfate; and step (4): cooling the slurry of magnesium sulfate in a crystallization box by cooling for crystallization to obtain a solid of magnesium sulfate and a remaining slurry of magnesium sulfate, and returning the slurry of magnesium sulfate remaining in the evaporator for a new concentration.
    In the present invention, a raw material of magnesium sulfite goes into a preparation box to be mixed with water to obtain a thick suspension of magnesium sulfite.
    In the present invention, the mass concentration of the slurry of magnesium sulfite is preferably 40 to 60%, more preferably 45 to 55%. The present invention does not have any special requirement for the kind of the raw material of magnesium sulfite, and the solid or the slurry of magnesium sulfite generated by desulfurization by a magnesium process is applicable to the process of the present invention.
    When the raw material of magnesium sulfite is slurry, the slurry enters the preparation box through the sampling pump, and the mass concentration of magnesium sulfite in the slurry is preferably not less than 60% ; and when the magnesium sulfite raw material is a solid, the solid raw material can be directly added from a sample inlet.
    The present invention processes the raw material of magnesium sulfite in the preparation box to obtain the slurry of magnesium sulfite having the concentration according to the requirements of the present invention, so that the magnesium sulfite generated by different power plants and power plants can be processed, and the adaptability is extremely high.
    In the present invention, the mixing mode is preferably agitation, and the agitation speed is preferably 300 to 600 rpm. In the present invention, a pH regulator is preferably added to the magnesium sulfite slurry preferably using a chemical dispenser in the preparation box to adjust the pH of the magnesium sulfite slurry to about 7. , to remove the chloride ion impurities in the slurry; and the pH regulator is preferably hydrochloric acid and / or sodium hydroxide. In the present invention, the slurry of magnesium sulfite is preferably filtered using a filter in the preparation box, to remove solid impurities in the slurry. The solid impurities are drained from the outlet for the impurities.
    After the slurry of magnesium sulfite has been obtained, in the present invention, the slurry of magnesium sulfite enters a reaction box and is contacted with a catalyst, and an oxidation reaction is carried out under conditions aeration to obtain a thick suspension of magnesium sulfate. In the present invention, the ratio of the mass of the catalyst to the volume of the slurry of magnesium sulphite is preferably 20 to 100 g / l, more preferably 40 to 80 g / l | ; and the gas for aeration is preferably air. In the present invention, the magnesium sulfite is fully in contact with oxygen by aeration; and in the present invention, the temperature of the oxidation reaction is preferably 40 to 70 ° C, more preferably 50 to 60 ° C. When an oxidation reaction is carried out, the present invention preferably uses a circulation pump to circulate the slurry of magnesium sulfite in the reaction box, and the flow rate during circulation of the slurry of magnesium sulfite. is preferably 14 to 15 m3 / h. In the present invention, by means of the circulation, the slurry of magnesium sulfite can be fully in contact with the catalyst layer to ensure the continuity of the production process while improving the catalytic efficiency.
    After the magnesium sulfate slurry has been obtained, in the present invention, the magnesium sulfate slurry enters an evaporator for concentration to obtain a concentrated slurry of magnesium sulfate.
    In the present invention, the concentration is preferably carried out under the stirring conditions, and the stirring speed is preferably 180 to 360 rpm.
    In the present invention, the concentration is preferably a vacuum concentration; the temperature of the concentration is preferably 40 to 70 ° C, more preferably 50 to 60 ° C.
    The volume of the concentrated magnesium sulfate slurry is preferably 40-70% that of the magnesium sulfate slurry before concentration, more preferably 50-60%. After the concentrated slurry of magnesium sulfate has been obtained, in the present invention, the slurry of magnesium sulfate enters a crystallization box by cooling for cooling and crystallization to obtain a solid of magnesium sulfate and a solid. remaining slurry of magnesium sulfate, and the slurry of remaining magnesium sulfate returned to the evaporator for further concentration.
    In the present invention, the temperature of the cooling crystallization is preferably 10 to ° C, more preferably 15 to 20 ° C; and the time is preferably 3 to 8 hours, more preferably 4 to 6 hours.
    In the present invention, after entering the evaporator, the remaining slurry of magnesium sulfate is mixed with the slurry of magnesium sulfate flowing into the reaction box, and then the slurry is concentrated.
    In the present invention, the remaining slurry of magnesium sulfate enters the evaporator for new concentration, so that the recovery rate of magnesium sulfate can be increased, and at the same time, in the oxidation process, concentration and crystallization, there is no disposal of residual waste and liquid waste, and the process is ecological and non-polluting.
    According to the process provided by the present invention, the raw material of magnesium sulfite and water can be continuously introduced to carry out a continuous reaction of catalytic oxidation, and the cobalt nitrate / {molecular friend ZSM-5 catalyst used has a long service life and can be used for several months without replacement.
    The present invention provides a cobalt nitrate / ZSM-5 molecular sieve catalyst, including a ZSM-5 molecular sieve and cobalt nitrate loaded into the ZSM-5 molecular sieve; and the mass loading capacity of cobalt nitrate in the cobalt nitrate / ZSM-5 molecular sieve catalyst is 2 to 15%, preferably 3 to 10%. In the present invention, the ZSM-5 cobalt nitrate / molecular sieve catalyst is a solid catalyst, which has a high catalytic speed and a service life of up to 3 to 6 months, and can avoid the pollution caused by a homogeneous catalyst when used to catalyze the oxidation of magnesium sulfite.
    The present invention provides a process for the preparation of cobalt nitrate catalyst / ZSM-5 molecular sieve, including the following step: Step (1): mixing of a ZSM-5 molecular sieve with a solution of cobalt nitrate for ion exchange to obtain a catalyst precursor.
    Step (2): Calcination of the catalyst precursor to obtain the cobalt nitrate / ZSM-5 molecular sieve catalyst. In the present invention, a ZSM-5 molecular sieve is mixed with a solution of cobalt nitrate for ion exchange to obtain a catalyst precursor.
    The present invention does not have any particular requirements for the source of the ZSM-5 molecular sieve, and a conventional commercially available ZSM-5 molecular sieve can be used.
    In the present invention, the molar concentration of the cobalt nitrate solution is preferably 0.1 to 0.3 mol, more preferably 0.15 to 0.2 mol / l; and the ratio of the mass of the ZSM-5 molecular sieve to the volume of the cobalt nitrate solution is preferably 2 to 10 g / 100 ml, more preferably 4 to 8 g / 100 ml.
    In the present invention, the ion exchange is carried out by immersing the ZSM-5 molecular sieve in a solution of cobalt nitrate.
    The ion exchange preferably includes a first ion exchange and a second ion exchange which are carried out successively, the temperature of the first ion exchange is preferably 80 ° C, and the time is preferably 24 h; after the first ion exchange is completed, in the present invention, replacement is preferably made with the cobalt nitrate solution for the second ion exchange; and the temperature and time of the second ion exchange are the same as those of the first ion exchange.
    In the present invention, cobalt ions are charged into the ZSM-5 molecular sieve by ion exchange.
    After completion of the ion exchange, in the present invention, an ion exchange system is preferably centrifuged, and the obtained solid material is sequentially washed and dried to obtain a catalyst precursor.
    In the present invention, the rotational speed of the centrifugation is preferably 4500 rpm; a detergent for washing is preferably deionized water, and the number of washing cycles is preferably 3. In the present invention, the drying temperature is preferably 80 ° C, and the time is preferably 6 h.
    After the catalyst precursor has been obtained, in the present invention, the catalyst precursor is calcined to obtain a cobalt nitrate / ZSM-5 molecular sieve catalyst. In the present invention, the calcination temperature is preferably 300 ° C, and the time is preferably 2 h; the heating rate for raising the temperature to the calcination temperature is preferably 2 ° C / min; and in the present invention, the calcination time begins to be calculated after the temperature has reached the calcination temperature.
    In the present invention, cobalt nitrate is decomposed by calcination to form cobalt oxide and cobalt pentoxide.
    Along with calcination, an active site is firmly attached to the surface of the catalyst, thereby improving the catalytic performance of the catalyst.
    After the ZSM-5 cobalt nitrate / molecular sieve catalyst has been obtained, the present invention also preferably forms the ZSM-5 cobalt nitrate / molecular sieve catalyst, and the formation preferably includes the following steps of: mixing nitric acid, pseudo-boehmite and sesbania powder with cobalt nitrate / ZSM-5 molecular sieve catalyst to obtain a gel-like mixture; and sequentially subjecting the gel-like mixture to extrusion molding, aging, drying and calcination to obtain a formed cobalt nitrate / ZSM-5 molecular sieve catalyst. In the present invention, the mass concentration of nitric acid is preferably 8 to 12%; and the gel-like mixture preferably includes, in weight percent, 19-21% pseudo-boehmite, 2.5-3.5% nitrous acid, 2.5-3.55% sesbania powder and 72-74% cobalt nitrate catalyst / ZSM-5 molecular sieve, and more preferably includes 20% pseudo-boehmite, 3% nitric acid, 3% sesbania powder and 74% nitrate catalyst cobalt / ZSM-5 molecular sieve.
    In the present invention, the method of mixing is preferably agitation. The present invention has no special requirements for the stirring time and the rotation speed, and it can be ensured that the above-mentioned materials are uniformly mixed to form a gel-like mixture.
    In the present invention, the extrusion molding is preferably carried out using an extruder, the extruded shape of the gel-like mixture is preferably a strip shape, and the diameter of the gel-like mixture is preferably 1 to 3mm, more preferably 2mm. In the present invention, the aging temperature is preferably 60 ° C, and the time is preferably 12 h; the drying temperature is preferably 80 ° C, and the time is preferably 6 h; the calcination temperature is preferably 300 ° C, and the time is preferably 2 h; in the present invention, the calcination time starts to be calculated after the temperature has reached the calcination temperature, and the heating rate for raising the temperature to the calcination temperature is preferably 2 ° C. / min. According to the present invention, the impurities such as moisture and nitric acid contained in the catalyst can be removed by calcination, and at the same time calcination increases the hardness of the catalyst and breaks down sesbania to form pores in the catalyst.
    In the present invention, after being assembled, the formed cobalt nitrate / molecular sieve catalyst ZSM-5 can be directly used as a catalyst layer of the device for the catalytic oxidation of magnesium sulfite provided by the present invention. The device and process for the catalytic oxidation of magnesium sulfite, the ZSM-5 cobalt / molecular amine nitrate catalyst and the process for the preparation thereof as provided by the present invention are described in detail below. below in conjunction with the embodiments, but the embodiments should not be construed as limiting the scope of protection of the present invention.
    Embodiment 1 Preparation of cobalt nitrate catalyst / ZSM-5 molecular sieve: (1) 4 g of ZSM-5 molecular sieve was added to 100 ml of 0.15 mol / l cobalt nitrate solution , and ion exchange was carried out in a water bath condition of 80 ° C for an exchange time of 24 h, and after the cobalt nitrate solution was replaced, the exchange of ions was repeated.
    (2) The above-mentioned solution was subjected to centrifugal separation at 4500 rpm, a supernatant was removed, and the solid was washed with deionized water three times.
    (3) The solid cleaned by centrifugation was dried in an 80 ° C drying oven for 6 h, calcined in a 300 ° C muffle furnace for 2 h, and the heating rate was 2 ° C / min to obtain a cobalt nitrate / ZSM-5 molecular sieve catalyst. The mass loading capacity of cobalt nitrate in the catalyst was 5%.
    A specific method for catalyzing the oxidation of magnesium sulfite using a obtained catalyst is as follows: 200 ml of deionized water was taken and placed in a reactor, and magnesium sulfite and a catalyst were added to the reactor, and air was introduced while timing was started. During the reaction, the pH of the system was adjusted with a concentrated solution of hydrochloric acid and a concentrated solution of sodium hydroxide. Then, the reaction solution was taken out and placed in a 100 ml volumetric flask using a pipette, and a 1: 1 hydrochloric acid solution was added to dissolve the white insoluble material therein, and the solution was diluted. with deionized water.
    The concentration of sulfate in the reactor at different times was determined by turbidimetry of barium sulfate.
    The specific operation was as follows: 50 ml of solution was placed in a 100 ml beaker, and 2.5 ml of stabilizer and a small rotor were added and the solution was placed on a magnetic stirrer for stirring at average speed ; after 0.2 g of cesium chloride was added, the mixture was stirred for 1 min and stood for 4 min.
    The 722 type light beam splitting photometer was used to measure the absorbance value, thereby estimating the C concentration of sulfate in the reactor at different times.
    Since the sulphate concentration in the system increases linearly with time, a slope k of a line Ct can be used to represent the rate of the oxidation reaction of magnesium sulphite, and is used as an index for evaluate the activity of the catalyst.
    During the tests, the obtained catalyst catalyzed the oxidation of magnesium sulfite at a rate of 0.036 mmol /// s.
    The use of the catalyst was omitted, and the oxidation rate of the obtained magnesium sulfite was 0.009 mmol / l / s.
    It can be found that the ZSM-5 cobalt nitrate / molecular sieve catalyst obtained by the present invention has a high oxidation rate, which is four times that without catalyst. 3% nitric acid, 20% pseudo-boehmite, 3% sesbania powder and 74% cobalt nitrate catalyst / ZSM-5 molecular sieve were mixed (the above components are all in mass percentage ) to obtain a gel-like mixture.
    The gel-like mixture was extruded into a 2mm strip, aged at 60 ° C for 12h, dried at 80 ° C for 6h, and calcined at 300 ° C for 2h to obtain a cobalt nitrate / sieve catalyst. molecular ZSM-5 formed as a catalyst layer in the device for the catalytic oxidation of magnesium sulfite for use.
    Embodiment 2
    Catalytic oxidation of magnesium sulfite solids in a desulfurization power plant by a magnesium process was carried out using the device for the catalytic oxidation of magnesium sulfite provided by the present invention. The specific process is as follows: (1) A raw material of magnesium sulphite entered into a preparation box to be mixed with water to obtain a thick suspension of magnesium sulphite by stirring, where the mass concentration of the Magnesium sulfite slurry was 45%.
    (2) The slurry of magnesium sulphite entered a reaction box to be contacted with a catalyst and was subjected to an oxidation reaction under an aeration condition of 200 m ° / h to obtain a magnesium sulfate slurry, where the temperature of the oxidation reaction was 45 ° C, the catalyst was the formed ZSM-5 cobalt nitrate / molecular sieve catalyst obtained in Embodiment 1, and the ratio of the mass of the catalyst to the volume of the slurry of magnesium sulphite was 40 g / l.
    (3) The magnesium sulfate slurry entered an evaporator for concentration at 55 ° C up to 60% of the original volume to obtain a concentrated magnesium sulfate slurry.
    (4) The magnesium sulfate slurry entered a crystallization box by cooling for cooling and crystallization below 20 ° C to obtain a magnesium sulfate solid and a remaining magnesium sulfate slurry, and the remaining slurry of magnesium sulfate was returned to the evaporator for further concentration.
    It was detected that the yield of the obtained magnesium sulfate solid was 100 kg / h, the purity was more than 99%, and the magnesium sulfite raw material was fully converted to the magnesium sulfate solid.
    Embodiment 3 Catalytic oxidation of magnesium sulfite solids in a desulfurization power plant by a magnesium process was carried out using the device for the catalytic oxidation of magnesium sulfite provided by the present invention. The specific process is as follows: (1) A raw material of magnesium sulfite is entered into a preparation box to be mixed with water; by stirring, after the pH was adjusted to 7, a magnesium sulfite slurry was obtained, where the mass concentration of the magnesium sulfite slurry was 55%.
    (2) The slurry of magnesium sulfite entered a reaction box to be contacted with a catalyst and was subjected to an oxidation reaction under an aeration condition of 198 m H to obtain a slurry. thick magnesium sulfate, where the temperature of the oxidation reaction was 65 ° C, and the catalyst was ZSM-5 cobalt nitrate / molecular sieve catalyst obtained in Embodiment 1, and the ratio of mass of the catalyst to the volume of the slurry of magnesium sulphite was 45 g / l.
    (3) The magnesium sulfate slurry entered an evaporator for concentration at 65 ° C up to 65% of the original volume to obtain a concentrated magnesium sulfate slurry.
    (4) The magnesium sulfate slurry entered a crystallization box by cooling for cooling and crystallization below 20 ° C to obtain a magnesium sulfate solid and a remaining magnesium sulfate slurry, and the remaining slurry of magnesium sulfate was returned to the evaporator for further concentration.
    It was detected that the yield of the obtained magnesium sulfate solid was 100 kg / h, the purity was more than 99%, and the magnesium sulfite raw material was fully converted to the magnesium sulfate solid.
    Embodiment 4 Catalytic oxidation of magnesium sulfite solids in a desulfurization power plant by a magnesium process was carried out using the device for the catalytic oxidation of magnesium sulfite provided by the present invention. The specific process is as follows: (1) A raw material of magnesium sulfite is entered into a preparation box to be mixed with water; by stirring, after the pH was adjusted to 7, a slurry of magnesium sulfite was obtained, where the mass concentration of the slurry of magnesium sulfite was 50%.
    (2) The slurry of magnesium sulfite entered a reaction box to be contacted with a catalyst and was subjected to an oxidation reaction under an aeration condition of 202 m ° / h to obtain a slurry of magnesium sulfate, where the temperature of the oxidation reaction was 55 ° C, the catalyst was cobalt nitrate / molecular sieve catalyst ZSM-5 obtained in Embodiment 1, and the ratio of mass of the catalyst to the volume of the slurry of magnesium sulphite was 42 g / l.
    (3) The magnesium sulfate slurry entered an evaporator for concentration at 65 ° C up to 65% of the original volume to obtain a concentrated magnesium sulfate slurry.
    (4) The magnesium sulfate slurry entered a crystallization box by cooling for cooling and crystallization below 20 ° C to obtain a magnesium sulfate solid and a remaining magnesium sulfate slurry, and the remaining slurry of magnesium sulfate was returned to the evaporator for further concentration.
    It was detected that the yield of the obtained magnesium sulfate solid was 100 kg / h, the purity was more than 99%, and the magnesium sulfite raw material can be fully converted into the magnesium sulfate solid.
    It can be seen from the above embodiments that the device provided by the present invention can achieve continuous catalytic oxidation of magnesium sulfite, and has high catalytic oxidation efficiency and does not cause pollution of the water. environment, and the raw material of magnesium sulphite can be fully converted into the solid of magnesium sulphate.
    The foregoing descriptions are only preferred embodiments of the present invention.
    It should be noted that for those skilled in the art, several improvements and modifications can furthermore be made without departing from the principle of the present invention.
    These improvements and modifications should also be considered to be within the scope of protection of the present invention.
    权利要求:
    Claims (10)
    [1]
    1. Device for the catalytic oxidation of magnesium sulphite, comprising: a preparation box (1); a reaction box (2) having an inlet communicating with an outlet of the preparation box, the reaction box comprising therein an aeration device (5) and a catalyst layer, and a catalyst of the preparation layer catalyst being a cobalt nitrate / ZSM-5 molecular sieve catalyst; an evaporator (3) having an inlet communicating with an outlet of the reaction box; and a cooling crystallization box (4) having an inlet communicating with an outlet of the evaporator, wherein the cooling crystallization box comprises a solid discharge port and a liquid discharge port, and The liquid discharge port communicates with the inlet of the evaporator.
    [2]
    Device according to claim 1, wherein the preparation box (1) is provided inside with a sampling pump, an agitator, a chemical dispenser and a filter; the evaporator (3) is provided internally with an air suction device, a heater and an agitator; and the cooling crystallization box (4) is internally provided with a cooling device and a rotary filter.
    [3]
    3. A process for the catalytic oxidation of magnesium sulfite using the device according to claim 1 or 2, comprising the following steps: step 1: mixing a raw material of magnesium sulfite with water in a can of preparation (1) to obtain a thick suspension of magnesium sulphite; step 2: contacting the slurry of magnesium sulfite with a catalyst in a reaction box (2) for an oxidation reaction under aeration conditions to obtain a slurry of magnesium sulfate; step 3: concentration of the slurry of magnesium sulfate in an evaporator (3) to obtain a concentrated slurry of magnesium sulfate; and step 4: cooling the slurry of magnesium sulfate in a cooling crystallization box (4) for crystallization to obtain a solid of magnesium sulfate and a slurry of remaining magnesium sulfate, and returning the slurry of magnesium sulfate remaining to the evaporator for a new concentration.
    [4]
    4. The method of claim 3, wherein the mass concentration of the slurry of magnesium sulfite in step (1) is 40 to 60%.
    [5]
    5. Process according to claim 3, wherein the ratio of the mass of the catalyst in step (2) to the volume of the slurry of magnesium sulphite is 20 to 100 g / l.
    [6]
    6. The method of claim 3, wherein the aeration gas in step (2) is air; and the temperature of the oxidation reaction is 40 to 70 ° C.
    [7]
    7. The method of claim 3, wherein the temperature of the concentration in step (3) is 40 to 70 ° C, the volume of the concentrated slurry of magnesium sulfate is 40 to 70% that of the. thick suspension of magnesium sulphate before concentration; and the temperature of the cooling crystallization in step (4) is 10 to ° C, and the time is 3 to 8 hours.
    25
    [8]
    8. ZSM-5 molecular sieve / cobalt nitrate catalyst, comprising ZSM-5 molecular sieve and cobalt nitrate loaded into ZSM-5 molecular sieve, wherein the mass loading capacity of cobalt nitrate in the catalyst of Cobalt nitrate / ZSM-5 molecular sieve is 2 to 15%.
    [9]
    9. A process for the preparation of the cobalt nitrate / ZSM-5 molecular sieve catalyst according to claim 8, comprising the following step:
    step 1: mixing a ZSM-5 molecular sieve with a solution of cobalt nitrate for ion exchange to obtain a catalyst precursor; and step 2: calcining the catalyst precursor to obtain the cobalt nitrate / ZSM-5 molecular sieve catalyst.
    [10]
    10. The preparation process according to claim 9, wherein the molar concentration of the cobalt nitrate solution is 0.1 to 0.3 mol / l; and the ratio of the mass of the ZSM-5 molecular sieve to the volume of the cobalt nitrate solution is 2 to 10 g / 100 ml.
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    同族专利:
    公开号 | 公开日
    CN110420659A|2019-11-08|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN103990360A|2014-03-06|2014-08-20|华东理工大学|Continuous concentration purification method for desulfurization by-product magnesium sulfate solution|
    CN105457479A|2015-12-31|2016-04-06|上海世渊环保科技有限公司|Flue gas desulphurization zero-emission resource disposal system and method|
    CN105709812A|2016-01-22|2016-06-29|柳州市海达新型材料科技有限公司|Cobalt-modified ZSM-5 zeolite molecular sieve catalyst and method for preparing same|
    CN106955733A|2017-03-02|2017-07-18|湖南云平环保科技有限公司|Desulphurization denitration catalyst of CuFeNiCo/ZSM 5 and preparation method thereof|
    CN101143335B|2007-10-11|2011-01-26|福州大学|Plasma reactor catalyst and its preparation method and use|
    CN103387246A|2012-05-09|2013-11-13|中节能六合天融环保科技有限公司|Treatment process suitable for rapidly oxidizing magnesium sulfite to magnesium sulfate|
    法律状态:
    2021-01-15| FG| Patent granted|Effective date: 20201130 |
    优先权:
    申请号 | 申请日 | 专利标题
    CN201910752483.3A|CN110420659A|2019-08-15|2019-08-15|A kind of device and method of catalysis oxidation magnesium sulfite, a kind of cobalt nitrate/ZSM-5 molecular sieve catalyst and preparation method thereof|
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