Apparatus for the purification of hydrocyanic acid synthesis gas

Abstract

The application provides a hydrogen cyanide synthesis gas ammonia removal and purification device, wherein an ammonia removal circulating assembly is arranged between an ammonia removal tower and a first liquid collecting pack, the top of the ammonia removal tower is provided with the first liquid collecting pack, a flow limiting orifice plate is arranged between the first liquid outlet of the first liquid collecting pack and the middle liquid inlet of the ammonia removal tower, an absorption circulating assembly is arranged between the bottom of an absorption tower and the middle of the absorption tower, the top of the absorption tower is provided with a second liquid collecting pack, a flow limiting orifice plate is arranged between the second liquid collecting pack and the middle of the absorption tower, and the distillation tower kettle discharge port is communicated with the second liquid collecting pack inlet and the liquid phase inlet at the upper end of the ammonia removal tower through pipelines. The hydrogen cyanide synthesis gas ammonia removal and purification device optimizes the process flow and the equipment structure, improves the ammonia absorption rate and the hydrogen cyanide recovery rate, simultaneously provides emergency treatment measures for abnormal working conditions in production, and provides a guarantee for the safe and stable operation of the hydrogen cyanide production device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical purification equipment, and particularly relates to a device for removing ammonia from hydrogen cyanide synthesis gas and purifying hydrogen cyanide. BACKGROUND

[0002] Hydrogen cyanide is a colorless liquid with the molecular formula HCN, a molecular weight of 27.03, a boiling point of 26 DEG C, and a bitter almond taste. Hydrogen cyanide is a highly hazardous and toxic medium, and the lethal dose is 1 mg / kg of body weight. The maximum allowable concentration of hydrogen cyanide in the air is 1 mg / m 3 (1 ppmv in volume).

[0003] Hydrogen cyanide is a widely used basic chemical raw material, and downstream products such as adiponitrile, methionine, sodium cyanide, insecticides, and herbicides have a large demand. Taking the downstream product adiponitrile as an example, an adiponitrile device with an annual output of 300,000 tons needs to consume tens of millions of tons of hydrogen cyanide every year. In recent years, with the breakthrough of the domestic adiponitrile technology, the demand for adiponitrile is more than one million tons, so the demand for hydrogen cyanide will also increase accordingly. Although hydrogen cyanide has a wide range of uses and a huge demand, due to its characteristics as a highly toxic medium, there are fewer domestic and foreign enterprises that master the safe production technology of hydrogen cyanide, thus limiting the large-scale development of hydrogen cyanide products.

[0004] In the synthesis method of hydrogen cyanide, whether it is the An process (methane ammonia oxidation method), BMA method, or methanol ammonia oxidation method, the hydrogen cyanide synthesis gas includes unreacted ammonia and product hydrogen cyanide that needs to be absorbed. The presence of ammonia can cause hydrogen cyanide to polymerize to produce black polymers, which can seriously block equipment pipelines and even cause explosions and other hazards. Therefore, a high-efficiency and safe ammonia removal process is needed before the absorption of hydrogen cyanide into a liquid phase. After the removal of ammonia, the product should be absorbed as much as possible, on the one hand to improve the product recovery rate, and on the other hand to avoid the HCN content in the tail gas exceeding the standard to affect the downstream incineration device. Therefore, there is an urgent need for a high-efficiency and safe process for removing ammonia from hydrogen cyanide synthesis gas and absorbing hydrogen cyanide.

[0005] Patent No. CN102502707A proposes a process for pressurized absorption of hydrogen cyanide from hydrogen cyanide synthesis gas. The pressurized absorption needs to set up a compressor, which increases the equipment investment. At the same time, the temperature of the synthesis gas after pressurization will increase, which will intensify the polymerization of hydrogen cyanide. In addition, the current hydrogen cyanide ammonia removal and absorption process has the following problems:

[0006] 1. The ammonia removal process is low in efficiency. The conventional pickling process will cause the ammonia gas to be entrained by the mist to the downstream absorption tower when the production load fluctuates, which will increase the ammonia content of the absorption tower.

[0007] 2. The hydrogen cyanide absorption process is unreasonable, which leads to a high temperature of the absorption tower, a large amount of absorbent, a large number of tray numbers, and high investment and energy consumption.

[0008] 3, not consider the accident condition of ammonia and hydrocyanic acid processing related emergency measures, resulting in ammonia and hydrocyanic acid content in the exhaust gas over standard; lead to production process can not long-term, safe, stable operation. SUMMARY

[0009] In view of this, the present application aims to provide a kind of hydrogen cyanide synthesis gas ammonia removal purification device, to provide efficient, safe ammonia removal and absorption process, reduce the occurrence of hydrogen cyanide production process polymerization, ensure that the device long-term stable operation.

[0010] To achieve the above object, the technical scheme of the present application is as follows:

[0011] A kind of hydrogen cyanide synthesis gas ammonia removal purification device, including the communication of ammonia removal tower, absorption tower and rectifying column in turn,

[0012] The lower section of ammonia removal tower is provided with a gas phase feed port, and the ammonia removal tower includes a countercurrent absorption section and a lean water washing section from bottom to top, the temperature of process gas after removing ammonia is between 40-60 ℃, the countercurrent absorption section can be a packing or a tray, and the packing is preferred, the lean water washing section is a bubble cap tray, a first liquid collecting package is arranged at the top of the ammonia removal tower, a first liquid outlet and a first overflow port arranged above the first liquid outlet are arranged on the first liquid collecting package, the first liquid outlet and the first overflow port are respectively connected to a middle liquid inlet of the ammonia removal tower through pipelines, a flow limiting orifice is arranged on the pipeline between the first liquid outlet and the middle liquid inlet of the ammonia removal tower, the liquid flow from the first liquid outlet to the middle liquid inlet of the ammonia removal tower is limited by the flow limiting orifice or a control valve, and the excess liquid overflows from the first overflow port to the ammonia removal tower, and the first liquid collecting package always maintains a liquid with a residence time of 5-15 min,

[0013] The gas phase feed port of the lower section of the absorption tower is connected to the gas phase outlet port at the top of the ammonia removal tower through a pipeline, an absorption circulating assembly is arranged between the circulating outlet port at the bottom of the absorption tower and the circulating reflux port in the middle of the absorption tower, a second liquid collecting package is arranged at the top of the absorption tower, a second liquid outlet and a second overflow port arranged above the second liquid outlet are arranged on the second liquid collecting package, the second liquid outlet and the second overflow port are respectively connected to a middle feed port of the absorption tower through pipelines, a flow limiting orifice is arranged on the pipeline between the second liquid outlet and the middle feed port of the absorption tower, the liquid flow from the second liquid outlet to the middle feed port of the absorption tower is limited by the flow limiting orifice, and the excess liquid overflows from the second overflow port of the second liquid collecting package to the absorption tower, and the second liquid collecting package always maintains a liquid with a residence time of 5-15 min,

[0014] The liquid inlet in the middle of the rectifying column is connected to the outlet port of the tower bottom of the absorption tower through a pipeline, and the outlet port of the tower bottom of the rectifying column is respectively connected to the feed port of the second liquid collecting package and the liquid phase feed port at the upper end of the ammonia removal tower through pipelines.

[0015] Further, the ammonia removal circulation assembly comprises an ammonia removal circulation pump and an ammonia removal cooler which are communicated by pipelines, the ammonia removal circulation pump is provided with three sets of pumps, two of which are in operation and one is in standby, and the standby pump is automatically started.

[0016] Further, a defoamer is arranged at the top of the ammonia removal tower, which can be a wire mesh defoamer, a cyclone plate defoamer or other defoamers, and is preferably a cyclone plate defoamer.

[0017] Further, the first liquid collecting package is further communicated with an acid absorbent adding pipe; the fresh acid used in the ammonia removal tower can be one or more of sulfuric acid, phosphoric acid and acetic acid, and is preferably sulfuric acid and phosphoric acid.

[0018] Further, the absorption circulation assembly comprises an absorption circulation pump and an absorption cooler which are communicated by pipelines.

[0019] Further, the lower end liquid supplementing port of the absorption tower is communicated with an emergency acid tank.

[0020] Further, a lean liquid pump and a lean liquid cooler are arranged on the pipeline between the distillation tower kettle discharge port and the second liquid collecting package feed port or the liquid phase feed port at the upper end of the ammonia removal tower.

[0021] Further, the mass flow rate of the hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase feed port of the lower section of the ammonia removal tower to the mass flow rate of the liquid in the ammonia removal circulation assembly is 1-10:1, and the mass flow rate of the hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase feed port of the lower section of the ammonia removal tower to the mass flow rate of the liquid entering the ammonia removal tower through the liquid phase feed port at the upper end of the ammonia removal tower is 20-50:1; preferably, the mass flow rate of the hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase feed port of the lower section of the ammonia removal tower to the mass flow rate of the liquid in the ammonia removal circulation assembly is 2-5:1, and the mass flow rate of the hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase feed port of the lower section of the ammonia removal tower to the mass flow rate of the liquid entering the ammonia removal tower through the liquid phase feed port at the upper end of the ammonia removal tower is 30-40:1.

[0022] Further, the pressure of the hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase feed port of the lower section of the ammonia removal tower is 0.01-0.1 MPaG, and the temperature is 150-250℃, and the temperature of the gas discharged from the gas phase discharge port at the top of the ammonia removal tower is 40-60℃.

[0023] Further, the temperature of the liquid entering the absorption tower through the middle inlet is 5-15 DEG C, the temperature of the liquid discharged through the tower bottom outlet is 20-30 DEG C, the inner part of the absorption tower is tray or packing, preferably tray, the total number of theoretical plates is 20-40, the number of theoretical plates below the circulation reflux port is 3-10, the absorbent is pure water, and the ratio of the mass flow rate of the gas entering the absorption tower through the gas phase inlet of the lower section to the mass flow rate of the liquid entering the second collecting vessel through the inlet of the second collecting vessel is 0.2-1:1.

[0024] Further, the ratio of the mass flow rate of the gas entering the absorption tower through the gas phase inlet of the lower section to the mass flow rate of the liquid entering the absorption tower through the circulation reflux port of the middle section is 0.2-1:1, and the temperature of the liquid entering the absorption tower through the circulation reflux port of the middle section is 10-20 DEG C.

[0025] Further, a demister is arranged at the top of the absorption tower, which can be a wire mesh demister, a cyclone plate demister or other demisters, preferably a cyclone plate demister.

[0026] Compared with the prior art, the hydrogen cyanide synthesis gas ammonia removal and purification device has the following advantages:

[0027] (1) The hydrogen cyanide synthesis gas ammonia removal and purification device optimizes the process flow and the equipment structure, improves the ammonia absorption rate and the hydrogen cyanide recovery rate, and provides emergency treatment measures for abnormal working conditions in production, thereby ensuring the safe and stable operation of the hydrogen cyanide production device;

[0028] (2) The ammonia removal tower and the absorption tower of the hydrogen cyanide synthesis gas ammonia removal and purification device are both provided with a collecting vessel, which can prevent ammonia or hydrogen cyanide from not entering the downstream system in the case of abnormal shutdown, thereby avoiding the polymerization of hydrogen cyanide due to the presence of ammonia or the shutdown of the downstream incineration device due to the excessive hydrogen cyanide content in the tail gas;

[0029] (3) The first collecting vessel of the hydrogen cyanide synthesis gas ammonia removal and purification device is in communication with the middle part of the ammonia removal tower, which effectively avoids the reduction of the washing effect caused by entrainment of mist, the absorption tower uses low-temperature absorption, and an absorption cooler is arranged, which significantly improves the absorption effect, and the recovery rate of hydrogen cyanide reaches more than 99.5%. BRIEF DESCRIPTION OF DRAWINGS

[0030] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0031] Figure 1The structure diagram of the ammonia removal and purification device for hydrogen cyanide synthesis gas.

[0032] Mark explanation:

[0033] 1, ammonia removal tower; 2, absorption tower; 3, rectification tower; 4, first liquid collecting package; 5, flow limiting orifice plate;

[0034] 6, second liquid collecting package; 7, ammonia removal circulating pump; 8, ammonia removal cooler; 9, absorption circulating pump; 10, absorption cooler; 11, emergency acid tank; 12, lean liquid pump; 13, lean liquid cooler; 14, rich liquid pump. DETAILED DESCRIPTION

[0035] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0036] The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] The ammonia removal and purification device for hydrogen cyanide synthesis gas of the present application comprises an ammonia removal tower 1, an absorption tower 2 and a rectification tower 3,

[0038] The lower section of the ammonia removal tower 1 is provided with a gas phase feed port for hydrogen cyanide synthesis gas, and the ammonia removal tower 1 comprises a countercurrent absorption section and a lean water washing section from bottom to top, the temperature of the process gas after removing ammonia is between 40-60℃, the countercurrent absorption section can be a filler or a tray, and the filler is preferred, and the lean water washing section is a bubble cap tray, a ammonia removal circulating assembly is arranged between the outlet of the tower kettle of the ammonia removal tower 1 and the feed port of the first liquid collecting package 4, the top of the ammonia removal tower 1 is provided with the first liquid collecting package 4, the first liquid collecting package 4 is provided with a first liquid outlet and a first overflow port arranged above the first liquid outlet, the first liquid outlet and the first overflow port are respectively communicated with the middle liquid inlet of the ammonia removal tower 1 through pipelines, a flow limiting orifice plate 5 is arranged on the pipeline between the first liquid outlet and the middle liquid inlet of the ammonia removal tower 1, the liquid flow from the first liquid outlet to the middle liquid inlet of the ammonia removal tower 1 is limited by the flow limiting orifice plate 5 or a control valve, and the excess liquid overflows from the first overflow port to the ammonia removal tower 1, and the first liquid collecting package 4 always maintains liquid with a residence time of 5-15min,

[0039] The gas phase feed inlet of the lower section of the absorption tower 2 is communicated with the gas phase outlet of the top of the ammonia removal tower 1 through a pipeline, the circulating outlet at the bottom of the absorption tower 2 is provided with an absorption circulating assembly communicated with the circulating reflux port of the middle section of the absorption tower 2, the second liquid collecting tank 6 is provided at the top of the absorption tower 2, the second liquid outlet and the second overflow port above the second liquid outlet are provided on the second liquid collecting tank 6, the second liquid outlet and the second overflow port are respectively communicated with the middle section feed inlet of the absorption tower 2 through pipelines, the pipeline between the second liquid outlet and the middle section feed inlet of the absorption tower 2 is provided with a flow limiting orifice plate 5, the liquid flow from the second liquid outlet to the middle section feed inlet of the absorption tower 2 is limited by the flow limiting orifice plate 5, and the excess liquid overflows from the second overflow port of the second liquid collecting tank 6 to the absorption tower 2, and the liquid with a residence time of 5-15 min is always kept in the second liquid collecting tank 6,

[0040] The liquid inlet of the middle section of the rectifying tower 3 is communicated with the tower outlet of the absorption tower 2 through a pipeline, and the tower outlet of the rectifying tower 3 is respectively communicated with the feed inlet of the second liquid collecting tank 6 and the liquid phase feed inlet of the upper end of the ammonia removal tower 1 through pipelines.

[0041] The ammonia removal circulating assembly comprises an ammonia removal circulating pump 7 and an ammonia removal cooler 8 communicated through a pipeline, the ammonia removal circulating pump 7 is provided with three pumps, two of which are used and one of which is reserved, and the reserved pump is automatically started.

[0042] A defoamer is arranged at the top of the ammonia removal tower 1, which can be a wire mesh defoamer, a cyclone plate defoamer or other defoamers, and is preferably a cyclone plate defoamer.

[0043] The feed inlet of the first liquid collecting tank 4 is also communicated with an acid absorbent adding pipe; the fresh acid used by the ammonia removal tower 1 can be one or more of sulfuric acid, phosphoric acid and acetic acid, and is preferably sulfuric acid and phosphoric acid.

[0044] The absorption circulating assembly comprises an absorption circulating pump 9 and an absorption cooler 10 communicated through a pipeline.

[0045] The emergency acid tank 11 is communicated with the liquid supplementing port at the lower end of the absorption tower 2.

[0046] The pipeline between the tower outlet of the rectifying tower 3 and the feed inlet of the second liquid collecting tank 6 or the liquid phase feed inlet of the upper end of the ammonia removal tower 1 is provided with a lean liquid pump 12 and a lean liquid cooler 13.

[0047] A defoamer is arranged at the top of the absorption tower 2, which can be a wire mesh defoamer, a cyclone plate defoamer or other defoamers, and is preferably a cyclone plate defoamer.

[0048] The operation process of the hydrogen cyanide synthesis gas ammonia removal and purification device is as follows:

[0049] The hydrogen cyanide synthesis gas S01 from the reactor enters the ammonia removal column 1, the hydrogen cyanide synthesis gas pressure is 0.01-0.1 MPaG, the temperature is 150-250℃, the bottom of the ammonia removal column 1 is provided with an ammonia removal circulating pump 7, the circulating liquid S02 is cooled by the ammonia removal cooler 8, mixed with fresh acid, and then enters the first liquid collection package 4 at the top of the ammonia removal column 1, the circulating liquid is divided into two streams S03 and S04 in the first liquid collection package 4, the flow rate of S02 is the sum of the flow rates of S03 and S04, the flow rate of S04 is limited by the flow limiting orifice plate 5, and the excess circulating liquid overflows from the first overflow port of the first liquid collection package 4 to the lower section, the first liquid collection package 4 always maintains the circulating liquid with a residence time of 5-15 min, when a power failure or pump failure accident occurs and the absorbing liquid cannot be circulated, the reactor is stopped, at the same time, the circulating liquid in the first liquid collection package 4 can still maintain the circulating liquid supply time of 5-15 min, so that ammonia gas is also captured and absorbed by the circulating liquid under the accident state; the fresh acid can be sulfuric acid, phosphoric acid or acetic acid, preferably sulfuric acid and phosphoric acid, the circulating liquid is in contact with the hydrogen cyanide synthesis gas in the countercurrent absorption section of the ammonia removal column 1, the process gas from which ammonia gas is removed is further subjected to a lean water washing section, so as to prevent the ammonia gas from being carried into the downstream absorption column 2 by gas mist entrainment, the countercurrent absorption section can be a packing or a tray, and the packing is preferred, the lean water washing section is a bubble cap tray, because the flow rate of the lean water washing liquid is small, the gas-liquid mass ratio of the process gas S01 to the circulating liquid S02 is 1-10:1, and the ratio is preferably 2-5:1; the gas-liquid mass ratio of the process gas S01 to the lean liquid S11 is 20-50:1, and the ratio is preferably 30-40:1; the absorbing liquid at the bottom of the column is sent to a sulfur ammonium device;

[0050] The process gas S05 after removing ammonia gas in the ammonia removal tower 1 has a temperature of 40-60°C, enters the absorption tower 2, and the middle section of the tower bottom of the absorption tower 2 is provided with reflux, the reflux liquid is sent to the absorption cooler 10 by the absorption circulating pump 9, and then returned to the tower after cooling, the tower top poor liquid absorbs hydrocyanic acid, and the tower bottom liquid S06 after absorbing hydrocyanic acid is a hydrocyanic acid-rich aqueous solution, referred to as rich liquid. The rich liquid is sent to the rectification tower 3 by the rich liquid pump 14, and the hydrocyanic acid and aqueous solution are purified by the rectification tower 3, the tower top obtains hydrocyanic acid product, and the tower bottom obtains aqueous solution containing trace hydrocyanic acid as poor liquid S07. The poor liquid S07 is sent to the second liquid collecting pack 6 of the absorption tower 2 after multi-stage cooling by the poor liquid pump 12 and the poor liquid cooler 13 through circulating water and refrigerated water, and the poor liquid is divided into two streams S08 and S09 in the second liquid collecting pack 6. The flow rate of S09 is limited by the flow limiting orifice plate 5, and the excess circulating liquid overflows from the second overflow hole of the second liquid collecting pack 6 to the lower section. The poor liquid is countercurrently absorbed with the process gas in the absorption tower 2, the tail gas S10 after absorbing hydrocyanic acid is sent to the waste gas incineration device, and the excess water S11 in the poor liquid is sent to the poor water washing section of the ammonia removal tower 1 as washing liquid. The temperature of the tower top poor liquid of the absorption tower 2 is 5-15°C, and the temperature of the tower bottom is 20-30°C. The inner part of the absorption tower 2 is a tray or a filler, and the tray is preferred. The total number of theoretical plates of the absorption tower 2 is 20-40, and the number of theoretical plates in the circulating section is 3-10. The absorption agent is pure water. The gas-liquid mass ratio of the process gas S05 to the poor liquid S07 is 0.2-1:1, and the gas-liquid mass ratio of the process gas S05 to the rich liquid S12 of the tower bottom is 0.2-1:1. The tower bottom temperature is cooled to 10-20°C and circulated to the middle section of the absorption tower 2. The middle section cooling reduces the temperature of the tower bottom and improves the absorption effect. The recovery rate of hydrocyanic acid reaches more than 99.5%, the content of hydrocyanic acid in the tower top tail gas is less than 100-200 ppm, and the poor liquid in the second liquid collecting pack 6 always maintains a residence time of 5-15 min. When a power failure or pump failure accident occurs and the absorption liquid cannot be circulated, the reactor is stopped. At the same time, the poor liquid in the second liquid collecting pack 6 can still maintain a poor liquid supply time of 5-15 min, ensuring that the hydrocyanic acid will also be captured and absorbed by the absorption liquid in the accident state. The absorption tower 2 system is provided with an emergency acid tank 11. Once the increase of ammonia gas content or polymer in the rich liquid is monitored, the emergency switch valve is opened to add polymerization inhibitor acid to the tower bottom of the absorption tower 2, the polymerization inhibitor is uniformly dispersed in the system by the poor liquid pump 12 and the rich liquid pump 14, the generated polymer is reacted with the acid, the absorption liquid is discharged to the incineration treatment, and the polymer will not accumulate in the system.

[0051] The rich liquid pump 14 and the poor liquid pump 12 are each provided with three pumps, two of which are used and one of which is reserved. The standby pump is automatically started. Even when one pump fails and cannot be opened, half of the poor liquid can still be circulated to absorb hydrocyanic acid.

[0052] Example

[0053] The typical composition of the hydrocyanic acid synthesis gas from the reactor is as follows

[0054] Substance Water Ammonia Hydrocyanic acid Nitrogen Carbon monoxide Composition wt% 10～20 1～5％ 1～10％ 50～70 1～5％

[0055] The flow of the synthetic gas is 100-150 t / h, the hydrogen cyanide synthesis gas ammonia removal purification device of the present application is used, the circulating liquid flow is 500-800 t / h, the lean liquid flow is 5-15 t / h, the top temperature of the ammonia removal tower 1 is 45℃, the bottom temperature is 75℃, the ammonia content in the process gas is reduced to below 20 ppm through the structure of the ammonia removal tower 1 of the present application;

[0056] The process gas after removing ammonia enters the absorption tower 2, the top temperature is maintained at 5℃, the bottom temperature is 20-30℃, the lean liquid flow is 250 t / h, the circulating liquid flow is 200 t / h, the hydrogen cyanide content in the tail gas at the top is less than 100 ppm.

[0057] Comparative example

[0058] The difference from example 1 is that the absorption circulating assembly is not arranged at the bottom of the absorption tower 2 in the comparative example, the top temperature of the absorption tower 2 is maintained at 5℃, the bottom temperature is 30-40℃, the lean liquid flow is 280 t / h, and the hydrogen cyanide content in the tail gas at the top is greater than 100 ppm.

Claims

1. A device for removing ammonia and purifying hydrogen cyanide synthesis gas, characterized in that: It includes an ammonia removal tower, an absorption tower, and a distillation tower connected in sequence. The lower section of the ammonia removal tower is equipped with a gas phase feed inlet. An ammonia removal circulation assembly is located between the tower bottom outlet and the inlet of the first liquid collection bag. This assembly includes an ammonia removal circulation pump and an ammonia removal cooler connected via pipelines. The top of the ammonia removal tower is equipped with a first liquid collection bag, which has a first liquid outlet and a first overflow outlet located above it. The first liquid outlet and the first overflow outlet are respectively connected to the middle liquid inlet of the ammonia removal tower via pipelines. A flow-limiting orifice plate is installed on the pipeline between the first liquid outlet and the middle liquid inlet of the ammonia removal tower. The gas phase inlet at the bottom of the absorption tower is connected to the gas phase outlet at the top of the ammonia removal tower via a pipeline. An absorption circulation assembly is installed between the circulation outlet at the bottom of the absorption tower and the circulation reflux outlet in the middle of the absorption tower. The absorption circulation assembly includes an absorption circulation pump and an absorption cooler connected via a pipeline. A second liquid collection tank is installed at the top of the absorption tower, with a second liquid outlet and a second overflow outlet located above the second liquid outlet. The second liquid outlet and the second overflow outlet are respectively connected to the feed inlet in the middle of the absorption tower via pipelines. A flow-limiting orifice plate is installed on the pipeline between the second liquid outlet and the feed inlet in the middle of the absorption tower. The liquid inlet in the middle of the distillation column is connected to the bottom outlet of the absorption column via a pipeline. The bottom outlet of the distillation column is connected to the inlet of the second liquid collection bag and the liquid phase inlet at the top of the ammonia removal column via pipelines.

2. The ammonia removal and purification apparatus for hydrogen cyanide synthesis gas according to claim 1, characterized in that: The inlet of the first liquid collection bag is also connected to an acid absorbent addition pipe.

3. The ammonia removal and purification apparatus for hydrogen cyanide synthesis gas according to claim 1, characterized in that: The lower end of the absorption tower is connected to an emergency acid tank via a liquid replenishment port.

4. The ammonia removal and purification apparatus for hydrogen cyanide synthesis gas according to claim 1, characterized in that: A lean liquor pump and a lean liquor cooler are installed on the pipeline between the bottom outlet of the distillation column and the inlet of the second liquid collection bag or the liquid phase inlet at the top of the ammonia removal column.

5. The ammonia removal and purification apparatus for hydrogen cyanide synthesis gas according to claim 1, characterized in that: The mass flow rate ratio of hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase inlet at the lower section of the ammonia removal tower to the mass flow rate of liquid in the ammonia removal circulation component is 1-10:1, and the mass flow rate ratio of hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase inlet at the lower section of the ammonia removal tower to the mass flow rate of liquid entering the ammonia removal tower through the liquid phase inlet at the upper end of the ammonia removal tower is 20-50:

1.

6. The ammonia removal and purification apparatus for hydrogen cyanide synthesis gas according to claim 1, characterized in that: The mass flow rate ratio of hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase inlet at the lower section of the ammonia removal tower to the mass flow rate of liquid in the ammonia removal circulation component is 2-5:1, and the mass flow rate ratio of hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase inlet at the lower section of the ammonia removal tower to the mass flow rate of liquid entering the ammonia removal tower through the liquid phase inlet at the upper end of the ammonia removal tower is 30-40:

1.

7. The ammonia removal and purification apparatus for hydrogen cyanide synthesis gas according to claim 1, characterized in that: The pressure of the hydrogen cyanide synthesis gas entering the ammonia removal tower through the gas phase feed port at the bottom of the tower is 0.01~0.1 MPaG, and the temperature is 150~250℃. The temperature of the gas discharged from the gas phase outlet at the top of the tower is 40~60℃.

8. The ammonia removal and purification apparatus for hydrogen cyanide synthesis gas according to claim 1, characterized in that: The temperature of the liquid entering the absorption tower through the feed inlet in the middle of the absorption tower is 5~15℃, and the temperature of the liquid discharged through the bottom outlet of the absorption tower is 20~30℃. The mass flow rate of the gas entering the absorption tower through the gas phase feed inlet in the lower section of the absorption tower and the mass flow rate of the liquid entering the second liquid collection bag through the feed inlet of the second liquid collection bag are 0.2~1:

1.

9. The ammonia removal and purification apparatus for hydrogen cyanide synthesis gas according to claim 1, characterized in that: The mass flow rate of the gas entering the absorption tower through the gas phase inlet at the bottom of the absorption tower is 0.2 to 1:1, and the temperature of the liquid entering the absorption tower through the circulation reflux inlet at the middle of the absorption tower is 10 to 20°C.

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