Spray type device for continuously synthesizing oxamide

Abstract

The utility model relates to a spray type device for continuously synthesizing oxamide. Comprising a raw material supply part which is connected with an inlet of a spray type reactor, an outlet of the spray type reactor is connected with a centrifugal machine, a solid phase outlet of the centrifugal machine is connected with an oxamide treatment unit, and a liquid phase outlet of the centrifugal machine is connected with a methanol refining unit; the spray type reactor comprises a reactor shell, at least one group of opposed atomizing nozzles are arranged at the middle upper part of the reactor shell, the group of opposed atomizing nozzles comprise a dimethyl oxalate methanol solution nozzle and an ammonia methanol solution nozzle, and the dimethyl oxalate methanol solution nozzle and the ammonia methanol solution nozzle are oppositely arranged; a solid-liquid phase material outlet is formed in the bottom of the reactor shell; the method has the characteristics of continuous production and low energy consumption.

Description

Technical Field

[0001] The utility model relates to the field of oxalamide production, in particular to a spray-type continuous oxalamide synthesis device. Background Art

[0002] Oxamide, also known as oxalic acid diamide, has a molecular weight of 88.07 and a nitrogen content of 31.8%. It is slightly soluble in water, insoluble in ethanol and ether, non-hygroscopic, stable, and easy to store. It decomposes into ammonia and carbonic acid, making it an excellent, highly effective, slow-release fertilizer. Compared to traditional fast-acting nitrogen fertilizers in my country (such as ammonium carbonate), oxamide is less volatile, insoluble in water, and less susceptible to loss. It also offers a high nitrogen utilization rate, reducing economic losses and water pollution.

[0003] Currently, there are several main methods for preparing oxamide: 1. The hydrocyanic acid method, which uses hydrocyanic acid to synthesize cyanide, followed by hydrolysis to produce oxamide. This method contains highly toxic hydrocyanic acid, making it unsuitable for large-scale industrial production. 2. The ammonium oxalate thermal decomposition method, which uses ammonium oxalate to heat and dehydrate to produce oxamide, but the yield is low and unsuitable for industrialization. 3. The oxalate ester method, which uses oxalate ester aminolysis to produce oxamide and the corresponding alcohol. With the development of dimethyl oxalate production from synthesis gas in my country, the cost of dimethyl oxalate has dropped significantly, showing great prospects for industrialization. Chinese authorized invention patent CN 111495312B discloses an oxamide synthesis device and method, which directly sprays dimethyl oxalate by heating and melting it and then heating it with ammonia. This invention is only suitable for small-scale production. In actual production, the large amount of heat released and the molten solid state are prone to incomplete reaction. In addition, the generated methanol is highly volatile, making subsequent separation difficult and increasing energy consumption. Utility Model Content

[0004] In order to make up for the above deficiencies, the utility model provides a spray-type continuous oxamide synthesis device to solve the technical problems existing in the prior art.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] A device for continuously synthesizing oxalamide by spraying, comprising a raw material supply portion connected to an inlet of a spray reactor, an outlet of the spray reactor connected to a centrifuge, a solid phase outlet of the centrifuge connected to an oxalamide processing unit, and a liquid phase outlet of the centrifuge connected to a methanol refining unit; the spray reactor comprising a reactor shell, at least one group of opposed atomizing nozzles being provided at the middle and upper portion of the reactor shell, the group of opposed atomizing nozzles comprising a dimethyl oxalate methanol solution nozzle and an ammonia methanol solution nozzle, the dimethyl oxalate methanol solution nozzle and the ammonia methanol solution nozzle being arranged opposite to each other, and a solid and liquid phase material outlet being provided at the bottom of the reactor shell.

[0007] The beneficial effects of the utility model are as follows: by setting up a spray reactor, the dimethyl oxalate methanol solution and the ammonia methanol solution are sprayed against each other under the premise of atomization, and direct contact and ammoniolysis reaction are achieved. The above reaction process has the characteristics of being able to achieve continuous synthesis and low energy consumption. Furthermore, since the ammoniolysis reaction is based on atomization, the generated oxamide is in powder form, which can avoid the problem of blockage of related pipelines; furthermore, since the dimethyl oxalate is not melted, the defect of difficulty in separation in the later stage caused by methanol volatilization is avoided.

[0008] Preferably, the raw material supply unit includes a dimethyl oxalate storage tank, a methanol storage tank and a liquid ammonia storage tank;

[0009] Among them, the outlets of the dimethyl oxalate storage tank and the methanol storage tank are respectively connected to the dimethyl oxalate methanol solution stirring kettle, and the outlets of the methanol storage tank and the liquid ammonia storage tank are respectively connected to the ammonia absorber; the outlet of the dimethyl oxalate methanol solution stirring kettle is connected to the dimethyl oxalate methanol solution nozzle through the first solution pump, and the outlet of the ammonia absorber is connected to the ammonia methanol solution nozzle through the second solution pump.

[0010] Preferably, the top gas phase outlet of the reactor shell is connected to the inlet of the ammonia absorber.

[0011] Preferably, when there are multiple dimethyl oxalate methanol solution nozzles, the outlet of the dimethyl oxalate methanol solution stirred tank is respectively connected to the aforementioned multiple dimethyl oxalate methanol solution nozzles through a first solution pump; the dimethyl oxalate methanol solution nozzles and the ammonia methanol solution nozzles are arranged in a one-to-one correspondence, and the outlet of the ammonia absorber is respectively connected to the multiple ammonia methanol solution nozzles through a second solution pump.

[0012] Preferably, a heat exchange jacket is provided on the outside of the reactor shell, and a heat exchange medium inlet pipe and a heat exchange medium outlet pipe are provided on the heat exchange jacket.

[0013] Preferably, the oxamide processing unit includes a dryer connected to the solid phase outlet of the centrifuge, and the outlet of the dryer is connected to the oxamide packaging machine through a pulverizer.

[0014] Preferably, the methanol refining unit comprises a distillation tower connected to the liquid phase outlet of the centrifuge, the outlet of the distillation tower is connected to the methanol refiner, and the outlet of the methanol refiner is connected to the refined methanol storage tank.

[0015] Preferably, a tee is provided between the outlet of the distillation tower and the methanol refiner, a first valve is provided between the tee and the methanol refiner, and a second valve is provided between the third end of the tee and the refined methanol storage tank.

[0016] A spray-type continuous oxalamide synthesis device is prepared according to the above scheme. The utility model changes the traditional process route. Methanol is used as a solvent. Dimethyl oxalate and ammonia are dissolved in methanol respectively. The reaction is carried out in a spray reactor. The dimethyl oxalate methanol solution and the ammonia methanol solution are contacted in an atomized form and an aminolysis reaction occurs, thereby achieving the characteristics of improving reaction efficiency and realizing continuous reaction. The dimethyl oxalate methanol solution and the ammonia methanol solution are reacted in an atomized form. The generated oxalamide is in powder form, which can effectively avoid the problem of blockage of related pipelines. At the same time, a gas phase outlet is provided at the top of the spray reactor to realize the recovery and reuse of ammonia, thereby achieving the characteristic of reducing costs. The utility model only dissolves dimethyl oxalate and ammonia in methanol, which saves energy compared with traditional technologies and avoids the defect of methanol volatilization causing difficulty in separation in the later stage. The solid-liquid mixture discharged from the spray reactor is passed through a centrifuge to obtain crude oxalamide, which is then dried and crushed to finally obtain the desired oxalamide product. The liquid phase obtained by the centrifuge is removed by a distillation tower and can be sold or reused according to actual working conditions, thereby achieving the characteristic of reducing operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a structural diagram of the utility model;

[0019] Figure 2 This is a schematic structural diagram of the spray reactor of the utility model.

[0020] In the figure: 1. dimethyl oxalate storage tank; 2. methanol storage tank; 3. dimethyl oxalate methanol solution stirring tank; 4. liquid ammonia storage tank; 5. ammonia absorber; 6. reactor shell; 7. centrifuge; 8. dryer; 9. distillation tower; 10. pulverizer; 11. methanol refiner; 12. oxamide packaging machine; 13. refined methanol storage tank; 14. dimethyl oxalate methanol solution nozzle; 15. ammonia methanol solution nozzle; 16. solid-liquid material outlet; 17. first solution pump; 18. second solution pump; 19. heat exchange jacket; 20. heat exchange medium inlet pipe; 21. heat exchange medium outlet pipe; 22. first valve; 23. second valve. DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] The following is combined with Figure 1-2 The present application is further described in detail. The utility model is a spray-type continuous synthesis device for oxalamide, which includes a raw material supply part, which is connected to the inlet of the spray reactor, the outlet of the spray reactor is connected to the centrifuge 7, the solid phase outlet of the centrifuge 7 is connected to the oxalamide processing unit, and the liquid phase outlet of the centrifuge 7 is connected to the methanol refining unit; the spray reactor includes a reactor shell 6, and at least one group of opposed atomizing nozzles is provided in the middle and upper part of the reactor shell 6, and the group of opposed atomizing nozzles includes a dimethyl oxalate methanol solution nozzle 14 and an ammonia methanol solution nozzle 15, and the dimethyl oxalate methanol solution nozzle 14 and the ammonia methanol solution nozzle 15 are arranged opposite to each other, and a solid-liquid material outlet 16 is provided at the bottom of the reactor shell 6. The utility model uses dimethyl oxalate methanol solution and ammonia methanol solution as raw materials for reaction. Specifically, the dimethyl oxalate methanol solution and ammonia methanol solution are atomized and then contacted after atomization to achieve the characteristics of improving conversion rate, realizing continuous reaction, reducing energy consumption and avoiding oxamide blocking related pipelines. The methanol refining unit is used to recover the methanol solvent and the generated methanol, and the oxamide processing unit removes impurities from the crude oxamide generated inside the spray reactor. By setting up opposing atomizing nozzles, the reaction raw materials can be sprayed against each other. Through contact, collision, and contact between the liquid phase dimethyl oxalate methanol solution and the ammonia methanol solution, small molecules quickly undergo ammonolysis reaction to achieve the purpose of accelerating the reaction rate. In the above reaction process, alcohol is added for dissolution. On the one hand, not only the solid is converted into liquid, but also the ammonia that is easily vaporized is converted into liquid. The mutual collision intensifies the reaction and improves the yield.

[0023] Furthermore, the raw material supply unit includes a dimethyl oxalate storage tank 1, a methanol storage tank 2, and a liquid ammonia storage tank 4; wherein, the outlets of the dimethyl oxalate storage tank 1 and the methanol storage tank 2 are respectively connected to the dimethyl oxalate methanol solution stirring tank 3, and the outlets of the methanol storage tank 2 and the liquid ammonia storage tank 4 are respectively connected to the ammonia absorber 5; the outlet of the dimethyl oxalate methanol solution stirring tank 3 is connected to the dimethyl oxalate methanol solution nozzle 14 via a first solution pump 17, and the outlet of the ammonia absorber 5 is connected to the ammonia methanol solution nozzle 15 via a second solution pump 18. The raw material supply unit described in the present invention is used to supply raw materials and achieve the dissolution of dimethyl oxalate and methanol, as well as the dissolution of methanol and ammonia. The above dissolution can make the materials all become liquid phase without heating (on the basis of reducing energy consumption), laying the foundation for subsequent atomization and continuous reaction.

[0024] Furthermore, the top gas phase outlet of the reactor shell 6 is connected to the inlet of the ammonia absorber 5. The gas phase discharged from the top gas phase outlet of the reactor shell 6 is ammonia. By allowing the ammonia to enter the ammonia absorber 5, the ammonia gas can be recovered and reused, further achieving the characteristic of reducing ammonia consumption in the liquid ammonia storage tank 4.

[0025] Furthermore, when there are multiple dimethyl oxalate methanol solution nozzles 14, the outlet of the dimethyl oxalate methanol solution stirred tank 3 is connected to the multiple dimethyl oxalate methanol solution nozzles 14 via a first solution pump 17; the dimethyl oxalate methanol solution nozzles 14 and the ammonia methanol solution nozzles 15 are arranged in a one-to-one correspondence, and the outlet of the ammonia absorber 5 is connected to the multiple ammonia methanol solution nozzles 15 via a second solution pump 18. In order to accelerate the reaction, the utility model can be provided with multiple sets of opposed atomizing nozzles to achieve the characteristic of improving reaction efficiency.

[0026] Furthermore, a heat exchange jacket 19 is provided on the outside of the reactor shell 6, and a heat exchange medium inlet pipe 20 and a heat exchange medium outlet pipe 21 are provided on the heat exchange jacket 19. The provision of the heat exchange jacket 19 not only increases the reaction speed of the material but also fully utilizes the heat, accelerates the dissolution rate of dimethyl carbonate, and improves continuous productivity.

[0027] Furthermore, the oxalamide processing unit includes a dryer 8 connected to the solid phase outlet of the centrifuge 7, and the outlet of the dryer 8 is connected to the oxalamide packaging machine 12 through a crusher 10. The centrifuge 7 described in the present invention is used to achieve solid-liquid separation. The separated solid phase is dried and crushed by the dryer 8 and then enters the oxalamide packaging machine 12 for sale.

[0028] Furthermore, the methanol refining unit includes a distillation tower 9 connected to the liquid phase outlet of the centrifuge 7. The outlet of the distillation tower 9 is connected to a methanol refiner 11, and the outlet of the methanol refiner 11 is connected to a refined methanol storage tank 13. The liquid phase separated by solid and liquid in the centrifuge 7 is passed through the distillation tower 9 to remove impurities to obtain methanol, which is further refined by the methanol refiner 11 to obtain refined methanol for sale.

[0029] Furthermore, a tee is provided between the outlet of the distillation tower 9 and the methanol refiner 11, a first valve 22 is provided between the tee and the methanol refiner 11, and a second valve 23 is provided between the third end of the tee and the refined methanol storage tank 13. The above arrangement enables methanol reflux, thereby reducing operating costs.

[0030] The working principle of the utility model is as follows: an operating method of a spray-type continuous oxalamide synthesis device: step 1: the dimethyl oxalate in the dimethyl oxalate storage tank 1 is sent to the dimethyl oxalate methanol solution stirring kettle 3 after being measured, and the methanol in the methanol storage tank 2 is sent to the dimethyl oxalate methanol solution stirring kettle 3 after being measured to prepare the dimethyl oxalate methanol solution; the mass ratio of the dimethyl oxalate and methanol is 1:9-1:2, and the stirring time of the dimethyl oxalate methanol solution stirring kettle 3 is 5-40min; the stirring speed is 100-800rpm / min and the temperature is controlled at 30-45℃; step 2: the liquid ammonia in the liquid ammonia storage tank 4 is sent to the ammonia absorber 5, and the methanol in the methanol storage tank 2 is sent to the ammonia absorber 5 after being measured to prepare an ammonia methanol solution, the mass ratio of the ammonia methanol solution is 10%-30%; the stirring time is 5-30min, and the temperature of the ammonia absorber is -10-10℃. Step 3: The dimethyl oxalate methanol solution and the ammonia methanol solution described in the above steps 1 and 2 are fed into the dimethyl oxalate methanol solution nozzle 14 and the ammonia methanol solution nozzle 15 in the spray reactor for atomization. After atomization, the two raw materials are sprayed against each other through contact and collision, and the liquid phase dimethyl oxalate methanol solution contacts the ammonia methanol solution. The small molecules rapidly undergo an aminolysis reaction to achieve the purpose of accelerating the reaction rate and generate oxamide; the solid-liquid mixture of oxamide and methanol enters the centrifuge 7 through the outlet of the spray reactor, and the unreacted ammonia enters the ammonia absorber 5 through the top gas phase outlet of the reactor shell 6. The output pressure of the opposed atomizing nozzle is: 0.1MPa~3MPa, the temperature is: 25~50°C, and the molar ratio of solute ammonia to dimethyl oxalate is: 2~2.8:1. Step 4: The solid-liquid mixture of oxalamide and methanol described in step 3 enters the centrifuge 7 by gravity for solid-liquid separation, and the separated solid phase enters the dryer 8 for drying. The dried oxalamide is crushed by the crusher 10 to meet the packaging requirements and then sent to the oxalamide packaging machine 12 for packaging and then sold; the separated liquid phase enters the distillation tower 9 for distillation and impurity removal, and the methanol after distillation and impurity removal can enter the methanol storage tank 2 for recycling according to the actual working conditions, and the excess methanol enters the methanol refiner 11 for refining, and the refined methanol enters the refined methanol storage tank 13 for sale; the solid content of oxalamide separated from the solid and liquid by the centrifuge 7 is: 80~95%, and the operating temperature of the dryer 8 is: 40~80℃. This utility model not only improves conversion rates but also significantly shortens the residence time of reactants. Compared to the 2-3 hours residence time of conventional reactors, the spray reactor reaction can proceed continuously. Furthermore, while maintaining the same processing capacity, the size of the spray reactor can be significantly reduced, significantly reducing manufacturing costs. This invention offers the advantages of continuous production, small size, low reaction temperature, and low production costs. Furthermore, solid dimethyl oxalate and easily vaporized ammonia are liquefied, and the resulting methanol is recycled as a solvent.In addition, the present invention achieves continuous synthesis of oxalamide by providing a spray reactor. Specifically, the spray reactor allows direct contact between a methanolic solution of dimethyl oxalate and a methanolic solution of ammonia to produce an aminolysis reaction. The solid-liquid mixture exiting the reactor passes through a solid-liquid separation device to obtain crude oxalamide, which is then dried and crushed to obtain the desired oxalamide product. Methanol is recycled as a solvent and the product, with the excess refined and sold. The design concept of the present invention addresses issues such as the inability to continuously produce oxalamide, long reaction times in the reactor, clogging of reactant output equipment, and low conversion yields.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the present invention as claimed.

Claims

1. A spray-type continuous oxamide synthesis device, characterized in that: The device comprises a raw material supply part, the raw material supply part is connected to the inlet of the spray reactor, the outlet of the spray reactor is connected to a centrifuge (7), the solid phase outlet of the centrifuge (7) is connected to the oxamide processing unit, and the liquid phase outlet of the centrifuge (7) is connected to the methanol refining unit; The spray reactor comprises a reactor shell (6), wherein at least one group of opposed atomizing nozzles is provided in the middle and upper part of the reactor shell (6), wherein the group of opposed atomizing nozzles comprises a dimethyl oxalate methanol solution nozzle (14) and an ammonia methanol solution nozzle (15), and the dimethyl oxalate methanol solution nozzle (14) and the ammonia methanol solution nozzle (15) are arranged opposite to each other, and a solid-liquid phase material outlet (16) is provided at the bottom of the reactor shell (6).

2. The spray-type continuous oxamide synthesis device according to claim 1, characterized in that: The raw material supply unit includes a dimethyl oxalate storage tank (1), a methanol storage tank (2) and a liquid ammonia storage tank (4); The outlets of the dimethyl oxalate storage tank (1) and the methanol storage tank (2) are respectively connected to the dimethyl oxalate methanol solution stirring tank (3), and the outlets of the methanol storage tank (2) and the liquid ammonia storage tank (4) are respectively connected to the ammonia absorber (5); The outlet of the dimethyl oxalate methanol solution stirring kettle (3) is connected to the dimethyl oxalate methanol solution nozzle (14) through a first solution pump (17), and the outlet of the ammonia absorber (5) is connected to the ammonia methanol solution nozzle (15) through a second solution pump (18).

3. The spray-type continuous oxamide synthesis device according to claim 2, characterized in that: The top gas phase outlet of the reactor shell (6) is connected to the inlet of the ammonia absorber (5).

4. The spray-type continuous oxamide synthesis device according to claim 2, characterized in that: When there are multiple dimethyl oxalate methanol solution nozzles (14), the outlet of the dimethyl oxalate methanol solution stirring kettle (3) is connected to the multiple dimethyl oxalate methanol solution nozzles (14) respectively through the first solution pump (17); The dimethyl oxalate methanol solution nozzles (14) and the ammonia methanol solution nozzles (15) are arranged in a one-to-one correspondence, and the outlet of the ammonia absorber (5) is connected to the plurality of ammonia methanol solution nozzles (15) respectively through the second solution pump (18).

5. The spray-type continuous oxamide synthesis device according to claim 1, characterized in that: A heat exchange jacket (19) is provided on the outside of the reactor shell (6), and a heat exchange medium inlet pipe (20) and a heat exchange medium outlet pipe (21) are provided on the heat exchange jacket (19).

6. The spray-type continuous oxamide synthesis device according to claim 1, characterized in that: The oxalamide processing unit comprises a dryer (8) connected to the solid phase outlet of a centrifuge (7); the outlet of the dryer (8) is connected to an oxalamide packaging machine (12) via a pulverizer (10).

7. The spray-type continuous oxamide synthesis device according to claim 2, characterized in that: The methanol refining unit comprises a distillation tower (9) connected to the liquid phase outlet of the centrifuge (7), the outlet of the distillation tower (9) is connected to a methanol refiner (11), and the outlet of the methanol refiner (11) is connected to a refined methanol storage tank (13).

8. The spray-type continuous oxamide synthesis device according to claim 7, characterized in that: A tee is provided between the outlet of the distillation tower (9) and the methanol refiner (11), a first valve (22) is provided between the tee and the methanol refiner (11), and a second valve (23) is provided between the third end of the tee and the refined methanol storage tank (13).

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