Production equipment for preparing chlorine by catalytic oxidation of waste hydrochloric acid

Abstract

The utility model relates to the technical field of chlorine preparation through catalytic oxidation of waste hydrochloric acid, in particular to production equipment and a production process for chlorine preparation through catalytic oxidation of waste hydrochloric acid. Comprising a hydrochloric acid desorption tower, an oxidation reactor connected with the hydrochloric acid desorption tower, and an adsorption tower connected with the oxidation reactor, a waste hydrochloric acid inlet and a diluted hydrochloric acid outlet are formed in the hydrochloric acid desorption tower, and a hydrogen chloride saturated steam outlet is formed in the top of the hydrochloric acid desorption tower; a mixed raw material gas inlet is formed in the tower bottom of the oxidation reactor, and a mixed product gas outlet is formed in the tower top of the oxidation reactor; a mixed product gas inlet and a chlorine outlet are formed in the bottom of the adsorption tower, and an oxygen outlet is formed in the top of the adsorption tower; and the hydrogen chloride saturated steam outlet is connected with the mixed raw material gas inlet. According to the utility model, the waste hydrochloric acid is used as a raw material to prepare chlorine, so that the recycling of hydrogen chloride in the waste hydrochloric acid is realized, the recycling value of the waste hydrochloric acid is greatly improved, and the device has obvious advantages in the aspect of cyclic utilization of chlorine elements.

Description

Technical Field

[0001] The utility model relates to the technical field of preparing chlorine gas by catalytic oxidation of waste hydrochloric acid, in particular to production equipment for preparing chlorine gas by catalytic oxidation of waste hydrochloric acid. Background Art

[0002] Chlorine is a very important chemical product and raw material, widely used in chemical, metallurgical, papermaking, textile, pharmaceutical, petroleum, chemical, drinking water disinfection and environmental protection industries.

[0003] In recent years, the proportion of chemical products produced with chlorine as raw material has increased year by year, especially driven by the strong demand for PVC and isocyanate, the demand for chlorine is increasing; on the other hand, the industrial synthesis process of chlorine-containing chemical products is mostly a substitution reaction, that is, a large amount of chlorine is consumed and hydrogen chloride is also produced. Hydrogen chloride will be absorbed by water to produce a large amount of waste hydrochloric acid, and the sale and treatment of waste hydrochloric acid are difficult. Therefore, people are eager to find an economical and applicable method to convert waste hydrochloric acid into chlorine, realize the recycling of chlorine elements and zero emissions in the production process, which can not only solve the problem of the outlet of waste hydrochloric acid, but also meet the growing demand for chlorine in industry to a certain extent.

[0004] There are three main methods for producing chlorine from hydrochloric acid (hydrogen chloride): electrolysis, direct oxidation and catalytic oxidation.

[0005] The production of chlorine by hydrochloric acid electrolysis is a relatively traditional method. Hydrochloric acid undergoes electrolysis in an electrolytic cell. During the electrolysis process, hydrogen chloride molecules lose electrons at the anode, undergo oxidation reactions, and generate chlorine (Cl2); while at the cathode, hydrogen ions (H+) gain electrons, undergo reduction reactions, and generate hydrogen (H2). The electrolysis method requires large investments and high energy consumption, and is not economically cost-effective.

[0006] The direct oxidation method is a method of preparing Cl2 by directly oxidizing HCl using inorganic oxidants such as NO2, SO3, NOHSO4 and mixed acid HNO3 / H2SO4. The reaction is carried out in the liquid phase. Typical methods include the Weldson method, the Kel-Chlor process and the DEGUSSA method. The more prominent disadvantages of these methods are complex equipment, the generation of corrosive substances during the reaction, incomplete conversion of hydrogen chloride, difficulty in product separation, difficulty in treating waste liquid, and high energy consumption, so they cannot be widely used.

[0007] The catalytic oxidation method is a method of oxidizing HCl to generate C12 using air or oxygen as an oxidant in the presence of a catalyst. The chemical reaction equation is: The reaction process is an exothermic, reversible process with the advantages of low energy consumption and simple operation. It is currently the method that is easiest to industrialize.

[0008] The current industrial application of catalytic oxidation to produce chlorine uses a catalytic system with ruthenium oxide as the active component and titanium oxide as the carrier. A fixed-bed reactor with an annual capacity of 120,000 tons has been developed. Due to the high cost of ruthenium-based catalysts, based on a catalyst life of 16,000 hours, the catalyst accounts for about 100 yuan of the manufacturing cost per ton of chlorine, which does not have an economic cost advantage.

[0009] The selection of catalysts, the optimization of process routes and the development of reactors that can maximize the performance of catalysts are crucial. Therefore, there is an urgent need for a production process for chlorine production by catalytic oxidation of waste hydrochloric acid with high conversion rate, simple product separation and low operating cost. Utility Model Content

[0010] In view of the above situation, in order to overcome the defects of the prior art, the utility model provides a production device for preparing chlorine by catalytic oxidation of waste hydrochloric acid to solve the problems involved in the background technology.

[0011] To achieve the above object, the utility model provides the following technical solution: a production device for preparing chlorine gas by catalytic oxidation of waste hydrochloric acid, comprising a hydrochloric acid desorption tower, an oxidation reactor connected to the hydrochloric acid desorption tower, and an adsorption tower connected to the oxidation reactor;

[0012] The hydrochloric acid desorption tower is provided with a waste hydrochloric acid inlet and a dilute hydrochloric acid outlet, and the top of the hydrochloric acid desorption tower is provided with a saturated hydrogen chloride steam outlet;

[0013] The oxidation reactor has a mixed raw gas inlet at the bottom and a mixed product gas outlet at the top;

[0014] The adsorption tower has a mixed product gas inlet and a chlorine gas outlet at the bottom, and an oxygen outlet at the top;

[0015] The hydrogen chloride saturated steam outlet is connected to the mixed raw gas inlet, and the mixed product gas outlet is connected to the mixed product gas inlet.

[0016] Furthermore, a condenser, a hydrogen chloride compressor and a hydrogen chloride heater are sequentially arranged between the steam outlet and the mixed raw gas inlet of the hydrogen chloride saturated oxidation reactor of the hydrochloric acid desorption tower.

[0017] Furthermore, a dehydration tower, a drying tower and a compressor are provided between the mixed product gas outlet of the oxidation reactor and the mixed product gas inlet of the adsorption tower;

[0018] The chlorine gas outlet of the adsorption tower is connected to the mixed raw gas inlet of the oxidation reactor.

[0019] Furthermore, the raw gas entering the mixed raw gas inlet of the oxidation reactor is oxygen and hydrogen chloride gas, the molar ratio of oxygen to hydrogen chloride gas is 1:1-4, and a copper-based catalyst is placed in the oxidation reactor;

[0020] A bottom reboiler is provided at the bottom of the hydrochloric acid desorption tower;

[0021] An oxygen heater is also provided at the mixed raw gas inlet of the oxidation reactor;

[0022] The oxidation reactor is a fixed bed reactor or a fluidized bed reactor.

[0023] Furthermore, the reaction pressure in the oxidation reactor is 0.1-0.5 MPa, and the reaction temperature is 350-450° C.;

[0024] The pressure of the dehydration tower and the drying tower is 0.1-0.5 MPa, and the temperature is 20°C-60°C.

[0025] Furthermore, the temperature of the adsorption tower is between room temperature and 60°C, and the pressure is between 0.1 and 0.5 MPaG;

[0026] The adsorption tower is provided with a molecular sieve adsorbent, and the molecular sieve adsorbent is one of 3A, 4A, 5A, 10X or 13X;

[0027] A vacuum pump is provided at the chlorine outlet of the adsorption tower.

[0028] Furthermore, the oxidation reactor comprises a reactor shell, a gas distributor arranged inside the reactor shell, a fluidized bed and a heat exchange device arranged above the gas distributor, and a gas-solid separation device arranged above the heat exchange device, and the mixed raw gas inlet is connected to the gas distributor;

[0029] The heat exchange device comprises a cooling tube bundle, a cooling tube bundle outlet ring tube and a cooling tube bundle inlet ring tube connected to both ends of the cooling tube bundle;

[0030] The gas-solid separation device is composed of multiple cyclone separators, including a cylinder, a cone cylinder arranged at the lower end of the cylinder, a particle discharge pipe connected to the lower end of the cone cylinder, a drip valve is provided at the end of the particle discharge pipe, a tangential injection pipe is provided on one side of the cylinder, a cover plate and a center pipe are provided above the cylinder, and the end of the particle discharge pipe is immersed in the fluidized bed.

[0031] Furthermore, the adsorption tower is provided with two or more, the bottom of the adsorption tower is provided with a mixed gas inlet and a chlorine outlet, the top of the adsorption tower is provided with an oxygen outlet, an adsorption bed is provided in the adsorption tower, and an adsorbent is provided in the adsorption bed; a connecting pipe group is also provided between the adsorption towers, and the connecting pipe group is used to balance the internal pressure of the two adsorption towers;

[0032] The adsorption towers are provided with two or more, including a first adsorption tower and a second adsorption tower. The communicating pipe group includes a communicating pipe provided between the top of the first adsorption tower and the top of the second adsorption tower. A first valve is provided at the connection between the communicating pipe and the first adsorption tower, and a second valve is provided at the connection between the communicating pipe and the second adsorption tower. The mixed gas inlet, chlorine outlet and oxygen outlet are provided with a mixed gas inlet valve, a chlorine outlet valve and an oxygen outlet valve respectively, and a vacuum pump is provided at the chlorine outlet.

[0033] Production process of equipment for producing chlorine by catalytic oxidation of waste hydrochloric acid.

[0034] (1) Desorption of waste hydrochloric acid

[0035] Waste hydrochloric acid from outside the boundary is pumped into the waste hydrochloric acid inlet on the hydrochloric acid desorption tower after the flow rate is adjusted by an automatic regulating valve, sprayed down from the top of the hydrochloric acid desorption tower, and reversely contacts with the steam from the reboiler at the bottom of the tower to exchange mass and heat. The temperature gradually increases, so that the hydrogen chloride gas in the concentrated hydrochloric acid is desorbed. The saturated hydrogen chloride steam coming out of the saturated hydrogen chloride steam outlet at the top of the hydrochloric acid desorption tower is cooled by a condenser and sent to the oxidation reactor through a hydrogen chloride compressor. The remaining dilute hydrochloric acid is discharged from the dilute hydrochloric acid outlet;

[0036] (2) Catalytic oxidation reaction

[0037] Qualified hydrogen chloride gas is preheated by a hydrogen chloride heater, and oxygen-containing gas from outside is preheated by an oxygen-containing gas heater. The preheated hydrogen chloride gas and preheated oxygen-containing gas are mixed and then enter the oxidation reactor from the mixed raw gas inlet. In the oxidation reactor, hydrogen chloride and oxygen are catalyzed by a catalyst to react to generate chlorine and water. The reaction pressure is 0.1-0.5MPa and the temperature is 350-450°C. The reaction gas is discharged from the mixed product gas outlet after the catalyst is separated and recovered, and enters the dehydration tower and the drying tower in turn. The operating pressure of the dehydration tower and the drying tower is 0.1-0.5MPa and the operating temperature is 20°C-60°C.

[0038] (3) Separation of reaction gas

[0039] The reaction mixture after dehydration and drying is pressurized by the compressor and enters the adsorption tower through the mixed product gas inlet. Under the selective adsorption of the adsorbent, the H2O, Cl2, HCl, and N2 components are adsorbed, and O2 is discharged from the oxygen outlet on the top of the tower and enters the oxidation reactor through the mixed raw gas inlet as a circulating gas. When the front of the mass transfer zone of the adsorbed impurities reaches the reserved section of the bed outlet, the adsorption is stopped, the vacuum pump is started, and the product chlorine is obtained from the chlorine outlet by vacuuming.

[0040] Furthermore,

[0041] The catalytic oxidation reaction in the oxidation reactor is:

[0042] The preheated hydrogen chloride gas and oxygen enter the oxidation reactor from the mixed raw material gas inlet at a ratio of 1 to 4:1, are evenly distributed through the gas distributor, and then an oxidation reaction occurs under the action of the catalyst on the fluidized bed. At the same time, the heat exchange device performs heat exchange to reduce the ambient temperature. The product mixed gas after the reaction is separated from the catalyst particles through the gas-solid separation device. The product mixed gas enters the gas-solid separation device, enters from the tangential injection pipe, and moves downward in a spiral. The catalyst enters the particle discharge pipe through the conical cone, and the central pipe discharges the product gas mixture from which the entrained catalyst particles have been removed, and then is discharged from the mixed product gas outlet;

[0043] The adsorption process of the adsorption tower is:

[0044] a. Adsorption process

[0045] The mixed gas enters the first adsorption tower from the mixed gas inlet. Under the selective adsorption of the molecular sieve adsorbent, the chlorine adsorbent is adsorbed in the bed, while the oxygen directly passes through the bed and flows out from the oxygen outlet at the top of the tower.

[0046] b. Pressure equalization and pressure reduction process

[0047] After the adsorption process is completed, the mixed gas inlet valve and the oxygen outlet valve of the first adsorption tower are closed to stop the adsorption, and the first valve of the first adsorption tower and the second valve of the second adsorption tower are opened to put the higher pressure gas in the first adsorption tower into the lower pressure second adsorption tower which has completed the regeneration along the adsorption direction;

[0048] c. Vacuuming process

[0049] After the pressure equalization process is completed, the chlorine outlet valve of the chlorine outlet is opened, the other valves are closed, the vacuum pump is turned on, and the first adsorption tower is evacuated in the opposite direction of the adsorption direction to completely desorb the adsorbed chlorine and other impurity gases, and the second adsorption tower completes the adsorption process at the same time;

[0050] d. Voltage balancing and boosting process

[0051] Open the first valve of the first adsorption tower and the second valve of the second adsorption tower, and use the higher pressure gas from the second adsorption tower to increase the pressure of the first adsorption tower;

[0052] e. Product gas pressure boosting process

[0053] Slowly and steadily increase the pressure of the adsorption tower to the adsorption pressure using product gas.

[0054] Compared with the prior art, the beneficial effects of the utility model are:

[0055] The utility model uses waste hydrochloric acid as a raw material to prepare chlorine, realizes the recycling of hydrogen chloride in waste hydrochloric acid, and greatly improves the recycling value of waste hydrochloric acid. It effectively solves the problems of low conversion rate, large equipment investment and high operating cost of preparing chlorine from hydrogen chloride, and has significant advantages in the recycling of chlorine elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the connection structure of Example 1 of the utility model;

[0057] Figure 2 This is a schematic diagram of the internal structure of the oxidation reactor of Example 1 of the utility model;

[0058] Figure 3 This is a schematic diagram of the main structure of the gas-solid separation device of Example 1 of the utility model;

[0059] Figure 4 This is a schematic diagram of the connection structure of the adsorption tower in Example 1 of the utility model;

[0060] Figure 5 This is a schematic diagram of the structure of the adsorption tower of Example 1 of the utility model;

[0061] In the figure:

[0062] Hydrochloric acid desorption tower 1, oxidation reactor 2, adsorption tower 3; waste hydrochloric acid inlet 4, dilute hydrochloric acid outlet 5, hydrogen chloride saturated steam outlet 6, mixed raw gas inlet 7, mixed product gas inlet 8, chlorine outlet 9, oxygen outlet 10, mixed product gas outlet 12, condenser 13, hydrogen chloride compressor 14, hydrogen chloride heater 15, dehydration tower 16, drying tower 17, compressor 18, tower bottom reboiler 19, oxygen heater 20;

[0063] Shell 100, gas distributor 200, fluidized bed 300, heat exchange device 400, gas-solid separation device 500, skirt 600, hanger 700, material leg fixing frame 800, cooling tube bundle support frame 900, cooling tube bundle fixing frame 101; cylinder 110, upper head 120, lower head 130, lug 140, raw material inlet pipe 150; short pipe 210; cooling tube bundle 410, cooling tube bundle outlet ring pipe 420, cooling tube bundle inlet ring pipe 430, elbow 440, U-bolt 450; cylinder 510, cone cylinder 520, particle discharge pipe 530, drip valve 540, tangential injection pipe 550, center pipe 560, cover plate 570;

[0064] first adsorption tower 11, second adsorption tower 21, connecting pipe 31, first valve 41, second valve 51, mixed gas inlet 61, chlorine outlet 71, vacuum pump 81, oxygen outlet 91, mixed gas inlet valve 611, chlorine outlet valve 711, oxygen outlet valve 911,

[0065] Cylinder body 111 , upper end cap 121 , lower end cap 131 , gas outlet 141 , gas inlet 151 , gas distribution device 161 , adsorption bed 171 , wire mesh 181 , filter 191 . DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments; based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0067] Embodiment 1:

[0068] Depend on Figure 1-5 As shown,

[0069] A production equipment for producing chlorine by catalytic oxidation of waste hydrochloric acid,

[0070] It includes a hydrochloric acid desorption tower 1, an oxidation reactor 2 connected to the hydrochloric acid desorption tower 1, and an adsorption tower 3 connected to the oxidation reactor 2;

[0071] The hydrochloric acid desorption tower 1 is provided with a waste hydrochloric acid inlet 4 and a dilute hydrochloric acid outlet 5, and the top of the hydrochloric acid desorption tower 1 is provided with a saturated hydrogen chloride vapor outlet 6; the bottom of the oxidation reactor 2 is provided with a mixed raw gas inlet 7, and the top of the oxidation reactor 2 is provided with a mixed product gas outlet 12; the bottom of the adsorption tower 3 is provided with a mixed product gas inlet 8 and a chlorine gas outlet 9, and the top of the adsorption tower 3 is provided with an oxygen outlet 10; the saturated hydrogen chloride vapor outlet 6 is connected to the mixed raw gas inlet 7, and the mixed product gas outlet 12 is connected to the mixed product gas inlet 8.

[0072] A condenser 13, a hydrogen chloride compressor 14 and a hydrogen chloride heater 15 are sequentially arranged between the hydrogen chloride saturated steam outlet 6 and the mixed raw gas inlet 7 of the oxidation reactor 2 of the hydrochloric acid desorption tower 1. A dehydration tower 16, a drying tower 17 and a compressor 18 are also arranged between the mixed product gas outlet 12 of the oxidation reactor 2 and the mixed product gas inlet 8 of the adsorption tower 3; the chlorine gas outlet 9 of the adsorption tower 3 is connected to the mixed raw gas inlet 7 of the oxidation reactor 2. A bottom reboiler 19 is arranged at the bottom of the hydrochloric acid desorption tower 1; an oxygen heater 20 is also arranged at the mixed raw gas inlet 7 of the oxidation reactor 2; the oxidation reactor 2 is a fixed bed reactor or a fluidized bed reactor.

[0073] The raw gas entering the mixed raw gas inlet of the oxidation reactor 2 is oxygen and hydrogen chloride gas, the molar ratio of oxygen to hydrogen chloride gas is 1:1-4, and a copper-based catalyst is placed in the oxidation reactor;

[0074] The reaction pressure in the oxidation reactor is 0.1-0.5 MPa, and the reaction temperature is 350-450°C; the pressure of the dehydration tower and the drying tower is 0.1-0.5 MPa, and the temperature is 20°C-60°C. The temperature of the adsorption tower is room temperature-60°C, and the pressure is 0.1-0.5 MPaG; the adsorption tower is provided with a molecular sieve adsorbent, and the molecular sieve adsorbent is one of 3A, 4A, 5A, 10X or 13X.

[0075] The oxidation reactor includes a shell 100, a gas distributor 200 and a fluidized bed 300 arranged inside the shell 100, a heat exchange device 400 arranged above the gas distributor 200, and a gas-solid separation device 500 arranged above the heat exchange device 400; the shell 100 includes a cylinder 110, an upper head 120 arranged at the upper end of the cylinder 110, and a lower head 130 arranged below the cylinder 110, and a skirt 600 is also provided on the lower side of the shell 100. The gas distributor 200 is arranged above the inner side of the lower head 130. A hanger 700 and a material leg fixing frame 800 are provided inside the shell 100, and the hanger 700 and the material leg fixing frame 800 are used to fix the upper and lower sides of the gas-solid separation device 500 respectively. The shell 100 is provided with a cooling tube bundle support frame 900 and a cooling tube bundle fixing frame 101. The upper end of the heat exchange device 400 is fixed to the cooling tube bundle support frame 900 by a U-bolt 450, and the middle and lower side of the heat exchange device 400 are fixed to the cooling tube bundle fixing frame 101. A plurality of lugs 140 are provided on the inner side of the cylinder 110, and the cooling tube bundle fixing frames 101 are connected to the lugs 140 by bolts.

[0076] The heat exchange device 400 includes a cooling tube bundle 410, a cooling tube bundle outlet ring pipe 420 and a cooling tube bundle inlet ring pipe 430 connected to both ends of the cooling tube bundle 410; the cooling tube bundle 410 is composed of multiple groups of parallel tube bundles, each group of parallel tube bundles is composed of multiple tubes in an M-shaped tube coil, and each tube is connected by an elbow 440. The reaction of chlorine gas produced by catalytic oxidation of hydrogen chloride is an exothermic reaction, and the heat exchange device 400 is set to exchange heat. The heat exchange device 400 is provided with 9 to 73 groups of parallel tube bundles, and each group of tube bundles is composed of 10 to 12 tubes.

[0077] The gas-solid separation device 5 is composed of 2 to 5 cyclone separators connected in sequence, each cyclone separator is cascaded 2 to 3 stages, and the use of double-stage or multi-stage cyclone separators can solve the problem of incomplete separation of light and heavy substances in ordinary cyclone separators. When the gas passes through the catalyst at a speed of 0.2 to 0.4 m / s, the catalyst exhibits a stable turbulent flow. When the gas flow rate is lower than 0.2 m / s, a channel flow or turbulent flow will form in the catalyst, and when the flow rate is high, it will cause the catalyst to be carried away. The cyclone separator can circulate the catalyst particles discharged from the fluidized bed, especially the fraction with a range of about 15 to 45 μm, to the fluidized bed. The cyclone separator includes a cylinder 510, a cone 520 arranged at the lower end of the cylinder 510, a particle discharge pipe 530 connected to the lower end of the cone 520, a drip valve 540 is provided at the end of the particle discharge pipe 530, a tangential injection pipe 550 is provided on one side of the cylinder 510, a center pipe 560 is provided above the cylinder 510, and a cover plate 570 is provided above the cylinder 510. The tangential injection pipe 550 is provided with a tangential inlet or a spiral inlet for the inlet of the product gas mixture. Due to the tangential or spiral inlet, the product gas mixture to be separated is given a spiral downward motion; the catalyst enters the particle discharge pipe through a conical cone, and the end of the particle discharge pipe 530 is immersed in the fluidized bed 300, which can prevent the gas mixture from bypassing through the particle discharge pipe 530, or ensure that the gas mixture passes through the cyclone separator completely or substantially completely through the tangential inlet; the central pipe 560 is used to discharge the product gas mixture from which the entrained catalyst particles have been removed, and 90-99% of the entrained catalyst particles are deposited to the drip valve 540 at the lower end.

[0078] A raw material inlet pipe 150 is provided on one side of the housing 100, and the raw material inlet pipe 150 is connected to a gas distributor 200, and the gas distributor 200 is composed of a plurality of short tubes 210. The gas distributor 200 is made of special materials to effectively avoid corrosion and extend the service life of the equipment. The raw material gas enters the oxidation reactor through the raw material inlet pipe 150 and is redistributed through the gas distributor 200. The gas distributor 200 evenly distributes the gas pressure, flow rate, and turbulent kinetic energy, effectively improving the fluidization effect, reaction performance, and catalyst life of the catalyst. The fluidized bed 3 is arranged above the gas distributor 200, and a catalyst is arranged in the fluidized bed 300.

[0079] The adsorption tower is composed of two or more adsorption towers, and an adsorption bed 171 is provided in the adsorption tower, and an adsorbent is provided in the adsorption bed 171; a mixed gas inlet 61 and a chlorine outlet 71 are provided at the bottom of the adsorption tower, and the mixed gas pressure entering the mixed gas inlet 61 is 0.1-1.2MpaG. A vacuum pump 81 is provided at the chlorine outlet 71. An oxygen outlet 91 is provided at the top of the adsorption tower, and a mixed gas inlet valve 611, a chlorine outlet valve 711, and an oxygen outlet valve 911 are provided on the mixed gas inlet 61, the chlorine outlet 71, and the oxygen outlet 91, respectively. A connecting pipeline group is also provided between the two adsorption towers, and the connecting pipeline group is used to balance the internal pressure of the two adsorption towers. The adsorption tower is provided with two, including a first adsorption tower 11 and a second adsorption tower 21. The connecting pipe group includes a connecting pipe 31 disposed between the top of the first adsorption tower 11 and the top of the second adsorption tower 21. A first valve 41 is disposed at the connection between the connecting pipe 31 and the first adsorption tower 11, and a second valve 51 is disposed at the connection between the connecting pipe 31 and the second adsorption tower 21. A circulation pipe is disposed between the oxygen outlet 91 and the mixed gas inlet 61.

[0080] The adsorption tower includes a cylinder 111, an upper head 121 arranged at the upper end of the cylinder 111, and a lower head 131 arranged at the lower end of the cylinder 111, the upper head 121 is provided with a gas outlet 141, and the lower head 131 is provided with a gas inlet 151; a gas distribution device 161 is provided at the gas inlet 151 inside the cylinder 111, the adsorption bed 171 is provided above the gas distribution device 161, a wire mesh 181 is provided above the adsorption bed, and a filter 191 is provided at the gas outlet 151.

[0081] The oxygen purity of the product of the present application is ≥98%, the chlorine purity is ≥90%, the oxygen product yield is ≥98%, and the chlorine product yield is ≥98%.

[0082] Production process of equipment for producing chlorine by catalytic oxidation of waste hydrochloric acid.

[0083] (1) Desorption of waste hydrochloric acid

[0084] Waste hydrochloric acid from outside the boundary is pumped into the waste hydrochloric acid inlet on the hydrochloric acid desorption tower after the flow rate is adjusted by an automatic regulating valve, sprayed down from the top of the hydrochloric acid desorption tower, and reversely contacts with the steam from the reboiler at the bottom of the tower to exchange mass and heat. The temperature gradually increases, so that the hydrogen chloride gas in the concentrated hydrochloric acid is desorbed. The saturated hydrogen chloride steam coming out of the saturated hydrogen chloride steam outlet at the top of the hydrochloric acid desorption tower is cooled by a condenser and sent to the oxidation reactor through a hydrogen chloride compressor. The remaining dilute hydrochloric acid is discharged from the dilute hydrochloric acid outlet;

[0085] (2) Catalytic oxidation reaction

[0086] Qualified hydrogen chloride gas is preheated by a hydrogen chloride heater, and oxygen-containing gas from outside is preheated by an oxygen-containing gas heater. The preheated hydrogen chloride gas and preheated oxygen-containing gas are mixed at a molar ratio of 4:1 to 1:1 and then enter the oxidation reactor from the mixed raw material gas inlet. In the oxidation reactor, hydrogen chloride and oxygen are catalyzed by a copper compound catalyst to react to generate chlorine and water. The reaction pressure is 0.1 to 0.5 MPa and the temperature is 350 to 450°C. After separation and recovery of the catalyst, the reaction gas is discharged from the mixed product gas outlet and enters the dehydration tower and the drying tower in turn. The operating pressure of the dehydration tower and the drying tower is 0.1 to 0.5 MPa and the operating temperature is 20°C to 60°C.

[0087] The catalyst is recycled by using a separator, which effectively improves the catalyst utilization rate, reduces production costs, reduces environmental pollution, improves product quality, promotes circular economy and optimizes the production process. The separator includes a cyclone separator, a filter, etc. The separator can be built into the reactor or set at the gas phase outlet of the reactor.

[0088] (3) Separation of reaction gas

[0089] The reaction mixture after dehydration and drying is pressurized by the compressor and enters the adsorption tower through the mixed product gas inlet. Under the selective adsorption of the adsorbent, the H2O, Cl2, HCl, and N2 components are adsorbed, and O2 is discharged from the oxygen outlet on the top of the tower and enters the oxidation reactor through the mixed raw gas inlet as a circulating gas. When the front of the mass transfer zone of the adsorbed impurities reaches the reserved section of the bed outlet, the adsorption is stopped, the vacuum pump is started, and the product chlorine is obtained from the chlorine outlet by vacuuming.

[0090] The catalytic oxidation reaction in the oxidation reactor is:

[0091] The preheated hydrogen chloride gas and oxygen enter the oxidation reactor from the mixed raw material gas inlet at a ratio of 1 to 4:1, are evenly distributed through the gas distributor, and then an oxidation reaction occurs under the action of the catalyst on the fluidized bed. At the same time, the heat exchange device performs heat exchange to reduce the ambient temperature. The product mixed gas after the reaction is separated from the catalyst particles through the gas-solid separation device. The product mixed gas enters the gas-solid separation device, enters from the tangential injection pipe, and moves downward in a spiral. The catalyst enters the particle discharge pipe through the conical cone, and the central pipe discharges the product gas mixture from which the entrained catalyst particles have been removed, and then is discharged from the mixed product gas outlet;

[0092] The adsorption process of the adsorption tower is:

[0093] a. Adsorption process

[0094] The mixed gas enters the first adsorption tower from the mixed gas inlet. Under the selective adsorption of the molecular sieve adsorbent, the chlorine adsorbent is adsorbed in the bed, while the oxygen directly passes through the bed and flows out from the oxygen outlet at the top of the tower.

[0095] b. Pressure equalization and pressure reduction process

[0096] After the adsorption process is completed, the mixed gas inlet valve and the oxygen outlet valve of the first adsorption tower are closed to stop the adsorption, and the first valve of the first adsorption tower and the second valve of the second adsorption tower are opened to put the higher pressure gas in the first adsorption tower into the lower pressure second adsorption tower which has completed the regeneration along the adsorption direction;

[0097] c. Vacuuming process

[0098] After the pressure equalization process is completed, the chlorine outlet valve of the chlorine outlet is opened, the other valves are closed, the vacuum pump is turned on, and the first adsorption tower is evacuated in the opposite direction of the adsorption direction to completely desorb the adsorbed chlorine and other impurity gases, and the second adsorption tower 2 completes the adsorption process at the same time;

[0099] d. Voltage balancing and boosting process

[0100] Open the first valve of the first adsorption tower and the second valve of the second adsorption tower to increase the pressure of the first adsorption tower with the higher pressure effective gas in the second adsorption tower;

[0101] e. Product gas pressure boosting process

[0102] The pressure of the adsorption tower is slowly and steadily raised to the adsorption pressure using product gas oxygen through a circulation pipeline provided between the oxygen outlet and the mixed gas inlet.

[0103] The experimental results of the production equipment of this application are as follows:

[0104] 1. Experimental conditions: reaction pressure 0.1MPa, reaction temperature 450℃, dehydration tower and drying tower operating pressure 0.1MPa, dehydration tower and drying tower operating temperature 20℃, experimental results: product chlorine purity 95%, chlorine product yield 99%.

[0105] 2. Experimental conditions: reaction pressure 0.3MPa, reaction temperature 400℃, dehydration tower and drying tower operating pressure 0.3MPa, dehydration tower and drying tower operating temperature 40℃. Experimental results: product chlorine purity 96%, chlorine product yield 98%.

[0106] 3. Experimental conditions: reaction pressure 0.5MPa, reaction temperature 350℃, dehydration tower and drying tower operating pressure 0.5MPa, dehydration tower and drying tower operating temperature 60℃. Experimental results: product chlorine purity 96%, chlorine product yield 98%.

[0107] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A production equipment for preparing chlorine by catalytic oxidation of waste hydrochloric acid, characterized in that: It includes a hydrochloric acid desorption tower, an oxidation reactor connected to the hydrochloric acid desorption tower, and an adsorption tower connected to the oxidation reactor; The hydrochloric acid desorption tower is provided with a waste hydrochloric acid inlet and a dilute hydrochloric acid outlet, and the top of the hydrochloric acid desorption tower is provided with a saturated hydrogen chloride steam outlet; The oxidation reactor has a mixed raw gas inlet at the bottom and a mixed product gas outlet at the top; The adsorption tower has a mixed product gas inlet and a chlorine gas outlet at the bottom, and an oxygen outlet at the top; The hydrogen chloride saturated steam outlet is connected to the mixed raw gas inlet, and the mixed product gas outlet is connected to the mixed product gas inlet.

2. The production equipment for preparing chlorine by catalytic oxidation of waste hydrochloric acid according to claim 1, characterized in that: A condenser, a hydrogen chloride compressor and a hydrogen chloride heater are arranged in sequence between the steam outlet and the mixed raw gas inlet of the hydrogen chloride saturated oxidation reactor of the hydrochloric acid desorption tower.

3. The production equipment for preparing chlorine by catalytic oxidation of waste hydrochloric acid according to claim 1, characterized in that: A dehydration tower, a drying tower and a compressor are also provided between the mixed product gas outlet of the oxidation reactor and the mixed product gas inlet of the adsorption tower; The chlorine gas outlet of the adsorption tower is connected to the mixed raw gas inlet of the oxidation reactor.

4. The production equipment for preparing chlorine by catalytic oxidation of waste hydrochloric acid according to claim 1, characterized in that: A copper-based catalyst is placed in the oxidation reactor; A bottom reboiler is provided at the bottom of the hydrochloric acid desorption tower; An oxygen heater is also provided at the mixed raw gas inlet of the oxidation reactor; The oxidation reactor is a fixed bed reactor or a fluidized bed reactor.

5. The production equipment for preparing chlorine by catalytic oxidation of waste hydrochloric acid according to claim 1, characterized in that: The adsorption tower is provided with a molecular sieve adsorbent, and the molecular sieve adsorbent is one of 3A, 4A, 5A, 10X or 13X; A vacuum pump is provided at the chlorine outlet of the adsorption tower.

6. The production equipment for preparing chlorine by catalytic oxidation of waste hydrochloric acid according to claim 1, characterized in that: The oxidation reactor comprises a reactor shell, a gas distributor arranged inside the reactor shell, a fluidized bed and a heat exchange device arranged above the gas distributor, and a gas-solid separation device arranged above the heat exchange device, and the mixed raw gas inlet is connected to the gas distributor; The heat exchange device comprises a cooling tube bundle, a cooling tube bundle outlet ring tube and a cooling tube bundle inlet ring tube connected to both ends of the cooling tube bundle; The gas-solid separation device is composed of multiple cyclone separators, including a cylinder, a cone cylinder arranged at the lower end of the cylinder, a particle discharge pipe connected to the lower end of the cone cylinder, a drip valve is provided at the end of the particle discharge pipe, a tangential injection pipe is provided on one side of the cylinder, a cover plate and a center pipe are provided above the cylinder, and the end of the particle discharge pipe is immersed in the fluidized bed.

7. The production equipment for preparing chlorine by catalytic oxidation of waste hydrochloric acid according to claim 1, characterized in that: The adsorption towers are provided with two or more, the bottom of the adsorption tower is provided with a mixed gas inlet and a chlorine outlet, the top of the adsorption tower is provided with an oxygen outlet, an adsorption bed is provided in the adsorption tower, and an adsorbent is provided in the adsorption bed; a connecting pipe group is also provided between the adsorption towers, and the connecting pipe group is used to balance the internal pressure of the two adsorption towers; The adsorption towers are provided with two or more, including a first adsorption tower and a second adsorption tower. The communicating pipe group includes a communicating pipe provided between the top of the first adsorption tower and the top of the second adsorption tower. A first valve is provided at the connection between the communicating pipe and the first adsorption tower, and a second valve is provided at the connection between the communicating pipe and the second adsorption tower. The mixed gas inlet, chlorine outlet and oxygen outlet are provided with a mixed gas inlet valve, a chlorine outlet valve and an oxygen outlet valve respectively, and a vacuum pump is provided at the chlorine outlet.

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