Tail gas treatment device for producing sodium salt methyl cyanamide formate

Abstract

The utility model provides a tail gas treatment device for producing sodium salt cyanamide methyl formate, which comprises a washing tower, an alkaline washing tower and a circulating pump respectively connected with the washing tower and the alkaline washing tower, a gas inlet of the washing tower is communicated with a synthesis kettle tail gas output header pipe, and a gas outlet at the top of the washing tower is communicated with a gas inlet at the bottom of the alkaline washing tower. Each of the washing tower and the alkaline washing tower structurally comprises a first filler layer and a demister, and the demister is arranged at a preset height of the bottoms of the washing tower and the alkaline washing tower; a first spray head is arranged in the washing tower to spray cyanamide into the washing tower, tower kettle absorption liquid of the washing tower is communicated with the synthesis kettle, a second spray head is arranged in the alkaline washing tower and sprays liquid alkali into the alkaline washing tower, and tower kettle absorption liquid of the alkaline washing tower is communicated with the synthesis kettle. According to the utility model, the waste of methyl chloroformate is reduced, the volatilized methyl chloroformate is reused, the reaction process of the synthesis kettle is optimized in an auxiliary manner, and the production efficiency of sodium salt cyanamide methyl formate is improved.

Description

Technical Field

[0001] The present application relates to the field of chemical technology, and in particular to a tail gas treatment device for producing sodium salt cyanamide methyl formate. Background Art

[0002] Methyl cyanamide formate is an intermediate for synthesizing pesticides and medicines such as carbendazim and albendazole. The methyl cyanamide formate includes sodium salt methyl cyanamide formate. At present, the tail gas treatment in the production process of sodium salt methyl cyanamide formate in China is mainly based on activated carbon adsorption or alkali destruction. This tail gas treatment method is simple to operate and has strong practicality. However, waste alkali and other solid wastes are generated in this tail gas treatment process, and the methyl chloroformate in the product is wasted after direct alkali destruction treatment, which makes the tail gas treatment uneconomical and thus not very practical. Utility Model Content

[0003] The embodiment of the utility model provides a tail gas treatment device for producing sodium salt cyanamide methyl formate, which does not generate any waste or solid waste when recycling the tail gas, and the methyl chloroformate in the tail gas can be recycled into the system for producing sodium salt cyanamide methyl formate, thereby improving the economy and practicality of tail gas treatment and solving the problems in the prior art.

[0004] The utility model provides a tail gas treatment device for producing sodium salt cyanamide methyl formate, comprising a washing tower, an alkali washing tower and a circulating pump respectively connected to the washing tower and the alkali washing tower, the air inlet of the washing tower is connected to the tail gas output main pipe of the synthesis reactor, the top gas outlet of the washing tower is connected to the air inlet at the bottom of the alkali washing tower, and the treated tail gas is discharged from the air outlet at the top of the alkali washing tower;

[0005] The structures of the washing tower and the alkali washing tower both include: a first packing layer and a demister, wherein the demister is arranged at a preset height at the bottom of the washing tower and the alkali washing tower;

[0006] The washing tower is provided with a first nozzle inside, and the first nozzle sprays cyanamide into the washing tower. The tower bottom absorption liquid of the washing tower is connected to the synthesis reactor.

[0007] A second nozzle is provided inside the alkali washing tower, and the second nozzle sprays liquid alkali into the alkali washing tower. The alkali washing tower reactor absorption liquid is connected to the synthesis reactor.

[0008] Optionally, the second nozzle comprises an atomizing nozzle.

[0009] Optionally, the first nozzle and / or the second nozzle are provided in multiple groups and are evenly arranged in the tower body direction.

[0010] Optionally, the first filler layer includes: a filter screen and a filter medium wrapped in the filter screen.

[0011] Optionally, the demister is detachably connected to the inner wall of the tower body via a connector, and the connector is configured to adjust the installation position of the demister in the direction of the tower body.

[0012] Optionally, the bottom section of the alkali washing tower is provided with a cooler.

[0013] Optionally, the spraying direction of the nozzle of the second nozzle includes any direction in three-dimensional space.

[0014] The beneficial effects of the utility model are:

[0015] The methyl chloroformate volatilized in the process of manufacturing sodium salt cyanamide methyl formate will be discharged from the synthesis reactor along with the tail gas. After collecting the tail gas, if the methyl chloroformate is directly disposed of by the method of breaking alkali, the part of methyl chloroformate is wasted, resulting in a low efficiency of synthesis reactor synthesis. The tail gas treatment device provided by the utility model sequentially processes the tail gas through a washing tower and an alkali washing tower, and the tail gas after the final treatment is normally discharged, and the absorption liquid of the methyl chloroformate is re-entered into the synthesis reactor to continue to participate in the reaction as a synthesis reactant. Not only the waste of methyl chloroformate is reduced, the volatilized methyl chloroformate is reused, and the process of the synthesis reactor reaction is assisted and optimized, and the production efficiency of the sodium salt cyanamide methyl formate is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram showing the front structure of an exhaust gas treatment device provided in an embodiment of the present application;

[0017] Figure 2 A partial cross-sectional view showing the position of the kettle of a washing tower or an alkali washing tower in a tail gas treatment device provided in an embodiment of the present application.

[0018] Reference numerals:

[0019] 1. Washing tower; 2. Alkali washing tower; 3. Circulation pump; 4. Defoamer; 41. Connector; 6. Synthesis kettle. DETAILED DESCRIPTION

[0020] The technical solutions in the application embodiments will be described clearly and completely below in conjunction with the accompanying drawings in the application embodiments. In addition, the phrases "in one embodiment" or "in an embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics may be combined in one or more embodiments in any suitable manner.

[0021] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity from another entity, and do not necessarily require or imply any such actual relationship or order between these entities. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the article or terminal device including the elements.

[0022] In the process of manufacturing sodium salt cyanamide methyl formate, the methyl chloroformate volatilized will be discharged from the synthesis reactor 6 along with the tail gas. After the tail gas is collected, if the methyl chloroformate is directly disposed of by breaking the alkali, the part of the methyl chloroformate will be wasted, resulting in a low efficiency of the synthesis reactor 6.

[0023] Reference Figure 1 and Figure 2 As shown, the utility model provides an exhaust gas treatment device for producing sodium salt cyanamide methyl formate. The exhaust gas treatment device comprises a washing tower 1, an alkali washing tower 2, and a circulating pump 3 connected to the washing tower 1 and the alkali washing tower 2 respectively. The air inlet of the washing tower 1 is connected to the exhaust gas output main pipe of the synthesis reactor 6, and the top gas outlet of the washing tower 1 is connected to the air inlet at the bottom of the alkali washing tower 2. The treated exhaust gas is discharged from the air outlet at the top of the alkali washing tower 2. Among them, the structures of the washing tower 1 and the alkali washing tower 2 both include: a first packing layer and a demister 4, and the demister 4 is arranged at a preset height at the bottom of the washing tower 1 and the alkali washing tower 2; the washing tower 1 is provided with a first nozzle inside, and the first nozzle sprays cyanamide into the washing tower 1, and the tower bottom absorption liquid of the washing tower 1 is connected to the synthesis reactor 6; the alkali washing tower 2 is provided with a second nozzle inside, and the second nozzle sprays liquid alkali into the alkali washing tower 2, and the tower bottom absorption liquid of the alkali washing tower 2 is connected to the synthesis reactor 6; the circulating pump 3 is arranged to circulate the absorption liquid in the washing tower 1 and the alkali washing tower 2.

[0024] like Figure 1 As shown, the tail gas discharged from the synthesis reactor 6 enters the washing tower 1 from the air inlet at the bottom of the washing tower 1. The tail gas reacts with the sprayed cyanamide in the washing tower 1 to generate methyl cyanamide formate and hydrochloric acid. The liquid after the reaction is deposited at the bottom of the washing tower 1. The liquid contains hydrochloric acid and methyl cyanamide formate, which are passed into the synthesis reactor 6 again to participate in the synthesis reaction of sodium salt methyl cyanamide formate. Then, the tail gas after part of the methyl chloroformate is absorbed by cyanamide passes through the alkali washing tower 2 again. The liquid alkali sprayed in the alkali washing tower 2 reacts with methyl cyanamide formate to generate sodium salt methyl cyanamide formate, sodium chloride and water, and finally realizes the recycling process of methyl chloroformate recovery and reactant reuse.

[0025] The tail gas treatment device provided by the utility model sequentially processes the tail gas through a washing tower 1 and an alkali washing tower 2, and finally the treated tail gas is discharged normally, and the absorption liquid from which methyl chloroformate is recovered is introduced into the synthesis reactor 6 again as a synthesis reactant to continue to participate in the reaction. Not only does it reduce the waste of methyl chloroformate, so that the volatilized methyl chloroformate can be reused, but it also assists in optimizing the reaction process of the synthesis reactor 6, and improves the production efficiency of sodium salt cyanamide methyl formate.

[0026] In some embodiments, the second nozzle in the alkali washing tower 2 includes an atomizing nozzle, and the contact area between the atomized liquid alkali and the tail gas is increased, thereby improving the recovery efficiency of methyl chloroformate in the tail gas.

[0027] In some embodiments, the first nozzle in the washing tower 1 and / or the second nozzle in the alkali washing tower 2 are provided in multiple groups and are evenly arranged in the direction of the tower body. Because the exhaust gas is fluid, the exhaust gas discharged into the washing tower 1 or the alkali washing tower 2 fills the entire tower. The nozzles for spraying reactants are evenly arranged in the direction of the tower body so that the exhaust gas entering the tower can be covered by the nozzles as much as possible, thereby improving the reaction efficiency.

[0028] In some embodiments, the first filler layer includes: a filter screen, and a filter medium wrapped in the filter screen. The filter medium may be a filter medium capable of adsorption such as an adsorbent or activated carbon.

[0029] In some embodiments, the demister 4 in the washing tower 1 and the alkali washing tower 2 is detachably connected to the inner wall of the tower body through a connector 41, and the connector 41 is configured to adjust the installation position of the demister 4 in the direction of the tower body. Figure 2 As shown, by providing a connector 41, the demister 4 can be adjusted as the height of the liquid level in the tower kettle changes, thereby improving the defoaming effect and being compatible with defoaming actions at different liquid levels.

[0030] In other embodiments, a cooler is provided in the bottom section of the alkali washing tower 2. The cooler can reduce the temperature of the absorption liquid at the bottom of the tower to prevent the temperature from being too high, causing secondary volatilization or affecting the absorption effect.

[0031] In addition, the spraying directions of the nozzles of the first nozzle and the second nozzle include any direction in the three-dimensional space, which can increase the spraying range of the nozzles and improve the reaction efficiency.

[0032] Finally, the utility model provides a tail gas treatment device for producing sodium salt cyanamide methyl formate, comprising a washing tower 1, an alkali washing tower 2, and a circulating pump 3 respectively connected to the washing tower 1 and the alkali washing tower 2, the air inlet of the washing tower 1 is connected to the tail gas output main pipe of the synthesis reactor 6, the top gas outlet of the washing tower 1 is connected to the air inlet at the bottom of the alkali washing tower 2, and the treated tail gas is discharged from the air outlet at the top of the alkali washing tower 2. Among them, the structures of the washing tower 1 and the alkali washing tower 2 both include: a first packing layer and a demister 4, and the demister 4 is arranged at a preset height at the bottom of the washing tower 1 and the alkali washing tower 2; the washing tower 1 is provided with a first nozzle inside, the first nozzle sprays cyanamide into the washing tower 1, the tower bottom absorption liquid of the washing tower 1 is connected to the synthesis reactor 6, the alkali washing tower 2 is provided with a second nozzle inside, the second nozzle sprays liquid alkali into the alkali washing tower 2, and the tower bottom absorption liquid of the alkali washing tower 2 is connected to the synthesis reactor 6; the circulating pump 3 is arranged to circulate the absorption liquid in the washing tower 1 and the alkali washing tower 2. The utility model not only reduces the waste of methyl chloroformate, enables the volatilized methyl chloroformate to be reused, but also assists in optimizing the process of the synthesis reactor 6 reaction, thereby improving the production efficiency of sodium salt cyanamide methyl formate.

[0033] It should be noted that the above embodiments all belong to the same utility model concept, and the description of each embodiment has its own focus. For the parts not described in detail in individual embodiments, reference can be made to the description in other embodiments. Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other.

[0034] The above embodiments only express the implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A tail gas treatment device for producing sodium salt cyanamide methyl formate, characterized in that: The invention comprises a washing tower (1), an alkali washing tower (2) and a circulating pump (3) respectively connected to the washing tower (1) and the alkali washing tower (2); the air inlet of the washing tower (1) is connected to the tail gas output main pipe of the synthesis reactor (6); the top gas outlet of the washing tower (1) is connected to the air inlet at the bottom of the alkali washing tower (2); and the treated tail gas is discharged from the air outlet at the top of the alkali washing tower (2); The structures of the washing tower (1) and the alkali washing tower (2) both include: a first packing layer and a demister (4), wherein the demister (4) is arranged at a preset height at the bottom of the washing tower (1) and the alkali washing tower (2); A first nozzle is provided inside the washing tower (1), and the first nozzle sprays cyanamide into the washing tower (1). The tower bottom absorption liquid of the washing tower (1) is connected to the synthesis reactor (6); A second nozzle is provided inside the alkali washing tower (2), and the second nozzle sprays liquid alkali into the alkali washing tower (2). The absorbing liquid in the bottom of the alkali washing tower (2) is connected to the synthesis reactor (6).

2. The tail gas treatment device for producing sodium salt cyanamide methyl formate according to claim 1, characterized in that: The second spray head comprises an atomizing nozzle.

3. The tail gas treatment device for producing sodium salt cyanamide methyl formate according to claim 1, characterized in that: The first nozzles and / or the second nozzles are provided in multiple groups and are evenly arranged in the tower body direction.

4. The tail gas treatment device for producing sodium salt cyanamide methyl formate according to claim 1, characterized in that: The first filler layer includes: a filter screen and a filter medium wrapped in the filter screen.

5. The tail gas treatment device for producing sodium salt cyanamide methyl formate according to claim 1, characterized in that: The demister (4) is detachably connected to the inner wall of the tower body via a connector (41), and the connector (41) is configured to adjust the installation position of the demister (4) in the direction of the tower body.

6. The tail gas treatment device for producing sodium salt cyanamide methyl formate according to claim 1, characterized in that: The bottom section of the alkali washing tower (2) is provided with a cooler.

7. The tail gas treatment device for producing sodium salt cyanamide methyl formate according to claim 2, characterized in that: The spraying direction of the nozzle of the second spray head includes any direction in three-dimensional space.

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