Combination device for synthesizing oxalyl chloride

Abstract

The utility model discloses an oxalyl chloride synthesis combined device which comprises a solid oxalic acid storage tank, the solid oxalic acid storage tank is connected with solid feed metering equipment through a first transfer pump, and the solid feed metering equipment is arranged at the top of a reaction kettle for solid feed; a top gas outlet of the reaction kettle is connected with a tube pass feed port of the first condenser, a tube pass discharge port of the first condenser is connected with the first-stage tail gas water absorption tower, the first-stage tail gas water absorption tower is connected with the second-stage tail gas water absorption tower, and the second-stage tail gas water absorption tower is connected with the alkali liquor absorption tower. According to the utility model, the solid raw material oxalic acid is added by adopting the solid feed metering equipment, so that a small amount of oxalic acid can be quantitatively added in batches for multiple times, and the problems of difficulty in temperature control, more byproducts and low yield content caused by violent exothermic reaction due to one-time feeding are effectively avoided. The device disclosed by the utility model adopts three-stage tail absorption, so that hydrogen chloride gas generated by reaction can be fully recycled, and the hydrogen chloride is more thoroughly absorbed by the three-stage tail absorption.

Description

Technical Field

[0001] This utility model belongs to the field of chemical equipment technology, and relates to oxalyl chloride, specifically to an oxalyl chloride synthesis assembly device. Background Technology

[0002] Traditional methods for preparing oxalyl chloride, such as the oxalic acid chlorination method described in German patent DE2840438, are the mainstream production methods. Other methods include chlorination of oxalate esters such as dimethyl oxalate, diethyl oxalate, or diphenyl oxalate, tetrachloroethylene carbonate method, ethylene glycol chlorination method, and tetrachloroglycolide decomposition method. Other methods are limited in their application due to factors such as high cost, limited raw materials, or low yield.

[0003] While the traditional oxalic acid chlorination process has been widely used, there is limited information on related production equipment. Most of the available information consists of partial modifications to certain equipment. Furthermore, the process suffers from problems such as the intense exothermic reaction caused by the one-time addition of oxalic acid, difficulty in controlling the reaction temperature, the inability to reuse the hydrogen chloride gas in the tail, and the generation of large amounts of waste salt. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an oxalyl chloride synthesis combination device to solve the technical problem that the performance of the synthesis device in the existing technology needs to be further improved.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] An oxalyl chloride synthesis apparatus includes a solid oxalic acid storage tank, which is connected to a solid feed metering device via a first transfer pump. The solid feed metering device is installed on top of the reactor for solid feeding.

[0007] It also includes a phosphorus oxychloride storage tank, which is connected to the reactor for feeding via a fourth transfer pump.

[0008] It also includes a phosphorus pentachloride storage tank, which is connected to the reactor for feeding via a sixth transfer pump.

[0009] The top outlet of the reactor is connected to the tube-side feed inlet of the first condenser, the tube-side outlet of the first condenser is connected to the first-stage tail gas water absorption tower, the first-stage tail gas water absorption tower is connected to the second-stage tail gas water absorption tower, and the second-stage tail gas water absorption tower is connected to the alkali absorption tower.

[0010] The bottom outlet of the reactor is connected to the inlet of the distillation column via a second transfer pump. The top outlet of the distillation column is connected to the tube-side inlet of the second condenser. The tube-side outlet of the second condenser is connected to the oxalyl chloride receiving tank.

[0011] This utility model also has the following technical features:

[0012] The top outlet of the distillation column is also connected to the tube-side inlet of the third condenser, and the tube-side outlet of the third condenser is connected to the phosphorus oxychloride recovery tank. The phosphorus oxychloride recovery tank is connected to the phosphorus oxychloride storage tank through the third transfer pump.

[0013] The bottom outlet of the distillation column is connected to the phosphorus pentachloride storage tank via a fifth transfer pump.

[0014] The reactor is also equipped with a reactor coil jacket on its exterior; a thermometer and a pressure gauge are installed on the top of the reactor; and a stirrer is installed inside the reactor.

[0015] The solid feed metering equipment includes a temporary storage tank connected to a first transfer pump. The discharge port of the temporary storage tank is connected to a metering tank. An electronic weighing scale is installed inside the metering tank. The discharge port of the metering tank is connected to a feed tank. A feed screw is installed inside the feed tank. The feed screw is driven by a feed motor. The discharge port of the feed tank is connected to a reaction vessel.

[0016] The temporary storage tank is equipped with an electric scraper.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] (I) This utility model uses a solid feed metering device to add solid raw material oxalic acid, which can ensure that small amounts are added in batches and multiple times in quantitative quantities, effectively avoiding the problems of difficult temperature control, large by-products, and low yield caused by one-time feeding.

[0019] (II) The device of this utility model adopts a three-stage tail suction, which can fully recover and utilize the hydrogen chloride gas generated in the reaction, and the three-stage tail suction absorbs hydrogen chloride more thoroughly.

[0020] (III) The apparatus of this invention is applicable to the process of synthesizing oxalyl chloride using phosphorus oxychloride as solvent and phosphorus pentachloride and anhydrous oxalic acid as raw materials.

[0021] (IV) The combination device of this utility model is reasonably configured and can improve the oxalyl chloride content and yield. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the oxalyl chloride synthesis unit.

[0023] Figure 2 This is a schematic diagram of a solid feed metering device.

[0024] The labels in the diagram represent the following: 1-Solid oxalic acid storage tank, 2-First transfer pump, 3-Solid feed metering equipment, 4-Reaction vessel, 5-First condenser, 6-First stage tail gas water absorption tower, 7-Second stage tail gas water absorption tower, 8-Alkali absorption tower, 9-Distillation column, 10-Second condenser, 11-Oxalate chloride receiving tank, 12-Third condenser, 13-Phosphorus oxychloride recovery tank, 14-Third transfer pump, 15-Phosphorus oxychloride storage tank, 16-Fourth transfer pump, 17-Fifth transfer pump, 18-Phosphorus pentachloride storage tank, 19-Sixth transfer pump, 20-Reaction vessel coil jacket, 21-Thermometer, 22-Pressure gauge, 23-Agitator, 24-Second transfer pump, 25-Pipeline, 26-Valve.

[0025] 301 - Temporary storage tank; 302 - Metering tank; 303 - Electronic weighing scale; 304 - Feed tank; 305 - Feeding screw; 306 - Feeding motor; 307 - Electric scraper; 308 - Discharge control valve; 309 - Controller.

[0026] The specific content of this utility model will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, all components, equipment and raw materials in this utility model are based on components, equipment and raw materials known in the prior art.

[0028] In this invention, the various devices are mainly connected by pipes 25. Each pipe 25 is equipped with a valve 26 as needed, which is opened or closed according to process requirements. All valves 26 in this invention are commonly used valves in the prior art.

[0029] Following the above technical solution, the following are specific embodiments of this utility model. It should be noted that this utility model is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solution of this application fall within the protection scope of this utility model.

[0030] Example:

[0031] This embodiment provides a combined apparatus for the synthesis of oxalyl chloride, such as... Figure 1 As shown, it includes a solid oxalic acid storage tank 1, which is connected to a solid feed metering device 3 via a first transfer pump 2. The solid feed metering device 3 is installed on the top of the reactor 4 for solid feeding.

[0032] like Figure 1As shown, the top outlet of the reactor 4 is connected to the tube-side feed inlet of the first condenser 5, the tube-side outlet of the first condenser 5 is connected to the first-stage tail gas water absorption tower 6, the first-stage tail gas water absorption tower 6 is connected to the second-stage tail gas water absorption tower 7, and the second-stage tail gas water absorption tower 7 is connected to the alkaline solution absorption tower 8.

[0033] like Figure 1 As shown, the bottom outlet of the reactor 4 is connected to the inlet of the distillation column 9 via the second transfer pump 24, the top outlet of the distillation column 9 is connected to the tube-side inlet of the second condenser 10, and the tube-side outlet of the second condenser 10 is connected to the oxalyl chloride receiving tank 11.

[0034] As a preferred embodiment of this invention, such as Figure 1 As shown, the top outlet of the distillation column 9 is also connected to the tube-side inlet of the third condenser 12. The tube-side outlet of the third condenser 12 is connected to the phosphorus oxychloride recovery tank 13. The phosphorus oxychloride recovery tank 13 is connected to the phosphorus oxychloride storage tank 15 through the third transfer pump 14. The phosphorus oxychloride storage tank 15 is connected to the reactor 4 for feeding through the fourth transfer pump 16.

[0035] As a preferred embodiment of this invention, such as Figure 1 As shown, the bottom outlet of the distillation column 9 is connected to the phosphorus pentachloride storage tank 18 via the fifth transfer pump 17; the phosphorus pentachloride storage tank 18 is connected to the reactor 4 via the sixth transfer pump 19 for feeding.

[0036] As a preferred embodiment of this invention, such as Figure 1 As shown, a reactor coil jacket 20 is installed on the outside of the reactor 4; a thermometer 21 and a pressure gauge 22 are installed on the top of the reactor 4; and a stirrer 23 is installed inside the reactor 4. The thermometer 21 is used to detect the temperature inside the reactor 4, and its lower end extends into the reactor to 2 / 3 of its depth. The pressure gauge 22 is used to display the pressure inside the reactor 4 in real time. The stirrer 23 is preferably a polytetrafluoroethylene multilayer turbine stirrer.

[0037] In this embodiment, the solid feed metering device 3 is selected from commonly known solid feed metering devices in the art, or from those provided in this utility model, as needed. Figure 2 The solid feed metering device shown is described. As a preferred embodiment of this solution, such as... Figure 2 As shown, the solid feed metering device 3 includes a temporary storage tank 301 connected to the first transfer pump 2. The discharge port of the temporary storage tank 301 is connected to the metering tank 302. An electronic weighing scale 303 is installed inside the metering tank 302. The discharge port of the metering tank 302 is connected to the feed tank 304. A feed screw 305 is installed inside the feed tank 304. The feed screw 305 is driven by a feed motor 306. The discharge port of the feed tank 304 is connected to the reaction vessel 4.

[0038] As a preferred embodiment of this invention, such as Figure 2 As shown, an electric scraper 307 is installed inside the temporary storage tank 301. The electric scraper 307 is a commonly known electric scraper in the art.

[0039] In this embodiment, when the solid feed metering device 3 is in use, the material is temporarily stored in the temporary storage tank 301. When feeding, the material is scraped and dispersed by the electric scraper 307 on its lower edge and enters the metering tank 302. The material is weighed by the electronic weighing scale 303 and the solid material is sent into the reaction vessel 4 by the feed screw 305 in the feed tank 304.

[0040] As a preferred embodiment of this invention, such as Figure 2 As shown, a discharge control valve 308 is installed on the discharge port at the bottom of the temporary storage tank 301. Both the discharge control valve 308 and the feed motor 306 are connected to the controller 309. The controller 309 is a controller known in the art.

[0041] In this embodiment, the electronic weighing scale 303 adopts an electronic weighing scale known in the art.

[0042] In this embodiment, each device is equipped with nitrogen protection according to process requirements to maintain an inert gas protective atmosphere during the reaction process.

[0043] In this embodiment, the reactor 4 is an acid and alkali resistant enamel-lined reactor. The inner wall is coated with an anti-corrosion layer, which can resist corrosion from acidic gases.

[0044] In this embodiment, all raw materials used were dried and pretreated.

[0045] In this embodiment, the distillation column 9 is a packed distillation column, which is equipped with ceramic rectangular saddle packing with a diameter of φ=20-200mm.

[0046] In this embodiment, the absorption water needs to be replaced after the concentration of hydrochloric acid absorbed by the primary tail gas water absorption tower 6 and the secondary tail gas water absorption tower 7 reaches 12 mol / L; the alkaline solution absorption tower 8 is equipped with an exhaust valve, and the alkaline solution inside the alkaline solution absorption tower 8 is a sodium hydroxide aqueous solution with a concentration of 25 wt.%. The alkaline solution is replaced when the pH of the sodium hydroxide aqueous solution drops to between 7.5.

[0047] The specific process of oxalyl chloride synthesis using the oxalyl chloride synthesis combination device of this invention is as follows:

[0048] Anhydrous solid oxalic acid is fed into solid feed metering device 3 from solid oxalic acid storage tank 1. After precise metering in solid feed metering device 3, it is sent into reactor 4. The solvent phosphorus oxychloride is fed into reactor 4 from phosphorus oxychloride storage tank 15. The raw material phosphorus pentachloride is fed into reactor 4 from phosphorus pentachloride storage tank 18. The reaction takes place in reactor 4 to generate oxalyl chloride, resulting in a mixture containing oxalyl chloride and tail gas.

[0049] The mixture containing oxalyl chloride enters the distillation column 9 from the reactor 4. The distillation column 9 is heated by high-frequency electricity, with a maximum heating temperature of 150-200℃. When the temperature of the distillation column 9 is around 60℃ to 70℃, the distilled liquid is condensed through the second condenser 10 and then enters the oxalyl chloride receiving tank 11. When the temperature of the distillation column 9 is around 105℃ to 115℃, the distilled liquid is condensed through the third condenser 12 and then enters the phosphorus oxychloride recovery tank 13. The phosphorus oxychloride in the phosphorus oxychloride recovery tank 13 is recovered and sent to the phosphorus oxychloride storage tank 15.

[0050] After being cooled by the first condenser 5, the exhaust gas enters the first-stage exhaust gas water absorption tower 6, the second-stage exhaust gas water absorption tower 7, and the alkaline solution absorption tower 8 for tertiary absorption.

Claims

1. A combined apparatus for the synthesis of oxalyl chloride, characterized in that, Includes a solid oxalic acid storage tank (1), which is connected to a solid feed metering device (3) via a first transfer pump (2). The solid feed metering device (3) is installed on the top of the reactor (4) for solid feeding. It also includes a phosphorus oxychloride storage tank (15), which is connected to the reactor (4) for feeding via a fourth transfer pump (16); It also includes a phosphorus pentachloride storage tank (18), which is connected to the reactor (4) for feeding via a sixth transfer pump (19); The top outlet of the reactor (4) is connected to the tube side inlet of the first condenser (5), the tube side outlet of the first condenser (5) is connected to the first stage tail gas water absorption tower (6), the first stage tail gas water absorption tower (6) is connected to the second stage tail gas water absorption tower (7), and the second stage tail gas water absorption tower (7) is connected to the alkaline solution absorption tower (8). The bottom outlet of the reactor (4) is connected to the inlet of the distillation column (9) via the second transfer pump (24). The top outlet of the distillation column (9) is connected to the tube inlet of the second condenser (10). The tube outlet of the second condenser (10) is connected to the oxalyl chloride receiving tank (11).

2. The oxalyl chloride synthesis apparatus as described in claim 1, characterized in that, The top outlet of the distillation column (9) is also connected to the tube side inlet of the third condenser (12), and the tube side outlet of the third condenser (12) is connected to the phosphorus oxychloride recovery tank (13). The phosphorus oxychloride recovery tank (13) is connected to the phosphorus oxychloride storage tank (15) through the third transfer pump (14).

3. The oxalyl chloride synthesis apparatus as described in claim 1, characterized in that, The bottom outlet of the distillation column (9) is connected to the phosphorus pentachloride storage tank (18) via the fifth transfer pump (17).

4. The oxalyl chloride synthesis apparatus as described in claim 1, characterized in that, The reactor (4) is also equipped with a reactor coil jacket (20) on the outside; a thermometer (21) and a pressure gauge (22) are also installed on the top of the reactor (4); and a stirrer (23) is also installed inside the reactor (4).

5. The oxalyl chloride synthesis apparatus as described in claim 1, characterized in that, The solid feed metering device (3) includes a temporary storage tank (301) connected to the first transfer pump (2). The discharge port of the temporary storage tank (301) is connected to the metering tank (302). An electronic weighing scale (303) is installed in the metering tank (302). The discharge port of the metering tank (302) is connected to the feed tank (304). A feed screw (305) is installed in the feed tank (304). The feed screw (305) is driven by a feed motor (306). The discharge port of the feed tank (304) is connected to the reactor (4).

6. The oxalyl chloride synthesis apparatus as described in claim 5, characterized in that, The temporary storage tank (301) is equipped with an electric scraper (307).

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