Resource deamination, dust removal and purification system and method for hydrocyanic acid process gas of fluidized bed

Abstract

The invention provides a recycling deamination and dust removal purification system and a recycling deamination and dust removal purification method for fluidized bed hydrocyanic acid process gas, which adopt a composite deamination and decyanation dust removal technology to perform quenching, deamination and dust removal on the process gas and perform decyanation concentration on a tower kettle pregnant solution at the same time to recover catalytic particles and ammonia in an ultra-clean hydrocyanic acid removal process. The ammonia content of the purified process gas is less than 3 ppm, the dust content is less than 1 ppm, the hydrocyanic acid loss in the separation process is less, the yield is greater than 99.5%, the ammonia content of the produced water is less than 50 ppm, the purity of the produced ammonia is greater than 99.9%, the purification effect is good, the resource utilization rate is high, and the method is suitable for popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical purification, and further to a fluidized bed hydrocyanic acid process gas resource deammoniation dust removal purification system and method. Background Art

[0002] Among various hydrocyanic acid production process routes, the fluidized bed methanol ammoxidation process is currently the most advanced hydrocyanic acid production process due to its excellent heat transfer effect and scale advantages. In order to improve the selectivity and yield of the hydrocyanic acid reaction, an excess ammonia ratio is used, and air is used as an oxygen source to carry out the methanol ammoxidation reaction. Therefore, in addition to the target product hydrocyanic acid, nitrogen, and a small amount of by-products CO2 and CO, the process gas of the fluidized bed process for producing hydrocyanic acid also contains trace amounts of micron-sized catalyst particles and ammonia. Among them, the separation of ammonia and catalyst particles is the key to improving the yield of hydrocyanic acid, reducing separation energy consumption, and ensuring the long-term operation of the device. The separation process of ammonia is not only prone to cause the loss of hydrocyanic acid polymerization, but also incomplete deamination, which will affect the subsequent hydrocyanic acid as a raw material to synthesize adiponitrile. The catalyst particles will become crystal nuclei, aggravate the aggregation of oligomers, and cause the pressure drop of the separation tower to increase or even block. Therefore, in the production of hydrocyanic acid, the separation of ammonia and catalyst is crucial.

[0003] Since the ammonia content in the hydrocyanic acid process gas is relatively high, the optimal separation solution for ammonia is to be able to separate and recycle it to reduce the raw material consumption of ammonia.

[0004] In order to improve the recovery efficiency of ammonia, patent CN101264901B provides a technical solution of phosphoric acid (monoammonium), rich liquid (diammonium phosphate) decyanation, rich liquid (diammonium phosphate) analysis, and ammonia distillation recovery. This patent realizes the recovery of ammonia from hydrocyanic acid process gas and the recycling of absorption liquid. However, the disadvantage of the patent is that the temperature of its absorption tower is low, only 35°C to 45°C, but because the absorption temperature is too low, a large amount of hydrocyanic acid will dissolve into the absorption liquid, which is easy to cause hydrocyanic acid and ammonia to polymerize, resulting in the loss of hydrocyanic acid, and the polymer will block the decyanation tower, resulting in the inability of the device to operate for a long period of time. In addition, although this patent solves the recycling of the absorbent, since phosphoric acid is a weak acid, phosphoric acid is used as an absorbent, and the ammonia absorption efficiency is not high. The purified process gas is high and does not meet the index of ultra-clean ammonia removal.

[0005] Patent CN102530868B is a combined deammonification process of phosphoric acid and sulfuric acid for low ammonia concentration cyanide-containing process gas in ammonia oxidation processes such as acrylonitrile, toluene to benzonitrile, and xylene to dimethyl nitrile. The patent proposes to first use phosphoric acid or monoammonium phosphate as an absorption liquid to perform preliminary deammonification absorption on the process gas, and then use sulfuric acid to deeply absorb and deammonify the process gas. The rich liquid produced after phosphoric acid absorbs ammonia and the rich liquid produced after sulfuric acid absorbs ammonia are both subjected to a denitrification process to remove hydrocyanic acid from the two absorption liquids. Although the patent improves the removal efficiency of ammonia, the disadvantage is that the setting of the decyanation tower has high energy consumption and large investment.

[0006] In view of the defects of the existing hydrocyanic acid process gas purification technology, it is necessary to propose a multi-effect composite fluidized bed hydrocyanic acid process gas resource deammonification and dust removal purification system and method to achieve deep purification and resource separation and recycling of ammonia and catalyst. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a fluidized bed hydrocyanic acid process gas resource deammoniation dust purification system and method, which rapidly cools, deammonifies and removes dust on the hydrocyanic acid process gas with a dust content of 100-300ppm and 1-3% ammonia. The ammonia content in the purified process gas is less than 3ppm, and the dust content is less than 1ppm. At the same time, the rich liquid in the bottom of the tower is decyanized and concentrated, and the catalytic particles are recovered by solid removal. The ammonia content in the water produced in the bottom of the distillation tower is less than 50ppm, and the purity of the ammonia produced at the top of the tower is greater than 99.9%. In addition, the loss of hydrocyanic acid in the hydrocyanic acid removal process is small, the yield is greater than 99.5%, and the overall resource utilization rate of the system is high.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A fluidized bed hydrocyanic acid process gas resource deamination dust removal purification system, comprising: a deamination dust removal and decyanation unit and a rich liquid treatment unit; the deamination dust removal and decyanation unit comprises: a deamination tower and a deep ammonia removal tower connected in sequence according to the flow direction of the hydrocyanic acid process gas; the deamination tower is used to remove dust and ammonia from the hydrocyanic acid process gas, and simultaneously concentrate and decyanate the absorption liquid; the deep ammonia removal tower is used to deeply remove ammonia from the gas after ammonia removal; the rich liquid treatment unit comprises: a deamination tower and a deep ammonia removal tower connected in sequence according to the flow direction of the hydrocyanic acid process gas; the deamination tower is used to remove dust and ammonia from the hydrocyanic acid process gas, and simultaneously concentrate and decyanate the absorption liquid; the deep ammonia removal tower is used to deeply remove ammonia from the gas after ammonia removal; the rich liquid treatment unit comprises: a deamination tower and a deep ammonia removal tower are connected in sequence according to the flow direction of the hydrocyanic acid process gas; the ... The rich liquid microfiltration desolidification separator, the rich liquid degassing tank, the rich liquid analysis device and the ammonia distillation tower are connected in sequence in the rich liquid flow direction; the rich liquid microfiltration desolidification separator is used to separate the catalyst in the rich liquid; the rich liquid degassing tank is used to remove the residual entrained hydrogen cyanide and other gases in the rich liquid; the rich liquid analysis device is used to analyze the rich liquid to obtain ammonia concentrated gas and monoammonium phosphate absorbent that can be recycled to the deammonification tower; the ammonia distillation tower is used to distill the ammonia concentrated gas discharged from the top of the rich liquid analysis tower to obtain high-purity ammonia gas.

[0010] In some embodiments, the deamination tower includes, from bottom to top, a rapid cooling decyanation concentration zone, a deamination dust removal zone 1, and a deamination dust removal zone 2; the deamination dust removal and decyanation unit also includes a primary spray liquid circulation pipeline, a secondary spray liquid circulation pipeline, and a tertiary spray liquid circulation pipeline; a primary spray mechanism is provided in the rapid cooling decyanation concentration zone, and the primary spray mechanism is connected to the primary spray liquid circulation pipeline; a secondary spray mechanism is provided in the deamination dust removal zone 1, and the secondary spray mechanism is connected to the secondary spray liquid circulation pipeline; a tertiary spray mechanism is provided in the deamination dust removal zone 2, and the tertiary spray mechanism is connected to the tertiary spray liquid circulation pipeline.

[0011] In some embodiments, the deamination, dust removal and decyanation unit further includes a four-stage spray liquid circulation pipeline; a four-stage spray mechanism is provided in the deep ammonia removal tower, and the four-stage spray mechanism is connected to the four-stage spray liquid circulation pipeline.

[0012] In some embodiments, the rich liquid analysis device includes a rich liquid analysis tower and an ammonia concentrator, the ammonia concentrator is used to cool the gas discharged from the top of the rich liquid analysis tower to obtain liquid ammonia water and concentrated ammonia gas, the ammonia concentrator has a built-in cooling pipe, the feed inlet of the rich liquid analysis tower is connected to the liquid phase outlet of the rich liquid degassing tank through the cooling pipe of the ammonia concentrator, the gas phase outlet at the top of the rich liquid analysis tower is connected to the gas phase inlet of the ammonia concentrator; the liquid phase outlet at the bottom of the ammonia concentrator is connected to the liquid phase reflux port at the top of the rich liquid analysis tower; the ammonia concentrated gas outlet of the ammonia concentrator is connected to the gas phase inlet of the ammonia distillation tower.

[0013] In some embodiments, a liquid phase zone and a cooling zone are sequentially provided in the shell of the ammonia concentrator from bottom to top, the cooling zone is provided with the cooling pipe, the inlet and outlet of the cooling pipe are respectively connected to the liquid phase outlet of the rich liquid degassing tank and the feed port of the rich liquid analysis tower; the gas phase inlet of the ammonia concentrator is arranged on the side wall of the shell corresponding to the cooling zone; the ammonia concentrated gas outlet of the ammonia concentrator is arranged on the top of the shell; a liquid phase overflow port is provided on the side wall of the shell corresponding to the liquid phase zone, and the liquid phase overflow port is connected to the feed port of the rich liquid analysis tower.

[0014] In some embodiments, a distributed liquid receiving pan is further provided in the deamination tower; the distributed liquid receiving pan is provided between the quenching decyanation concentration zone and the deamination dust removal zone 1, and between the deamination dust removal zone 1 and the deamination dust removal zone 2; the distributed liquid receiving pan includes a bottom liquid receiving pan and a sunken circulating liquid buffer zone arranged between the bottom liquid receiving pan and the inner side wall of the tower, a plurality of gas distribution pipes and a plurality of downcomers; a plurality of air vents are provided on the bottom liquid receiving pan, and the plurality of air vents are distributed at intervals; the gas distribution pipes are connected to the air vents one by one; a cap is provided on the top of the gas distribution pipe, and a gap is provided between the cap and the top of the gas distribution pipe.

[0015] The present invention also provides a fluidized bed hydrocyanic acid process gas resource deamination dust removal purification method, which adopts the above-mentioned resource deamination dust removal purification system, including the hydrocyanic acid process gas ammonia removal dust removal step and the rich liquid treatment step; the ammonia removal dust removal and decyanation step comprises: the dust-containing and ammonia-containing hydrocyanic acid process gas enters the deamination tower, flows from bottom to top through the quenching decyanation concentration zone, the deamination dust removal zone 1 and the deamination dust removal zone 2 in turn to perform process gas dust removal and ammonia removal, and the absorption liquid is concentrated and decyanated, and the process gas after dust removal and removal of more than 95% of ammonia enters the depth The ammonia removal tower is in countercurrent contact with the spray liquid with sulfuric acid as the absorbent to complete deep ammonia removal, so as to obtain the purified process gas that can be discharged; the rich liquid treatment step comprises: the decyanated rich liquid produced in the tower kettle of the ammonia removal tower is discharged into the rich liquid microfiltration desolidification separator for solid removal, the rich liquid after the catalyst particles are removed enters the rich liquid degassing tank for degassing after heat exchange and temperature increase, the rich liquid after further removing the residual acidic gas such as hydrocyanic acid then enters the rich liquid analysis device for analysis, and the ammonia concentrated gas obtained by analysis enters the ammonia distillation tower for distillation, and finally obtains high-purity ammonia gas.

[0016] In some embodiments, the rich liquid treatment step further comprises: the rich liquid analysis device separates and obtains a lean liquid containing monoammonium phosphate, which is reused as an absorbent in the deammonification tower.

[0017] In some embodiments, the rich liquid discharged from the rich liquid degassing tank enters the cooling pipe in the ammonia concentrator as a cooling medium, exchanges heat with the gas discharged from the top of the rich liquid analysis tower to increase its temperature, and then enters the rich liquid analysis tower for analysis.

[0018] In some embodiments, the pH of the spray liquid in the quenching decyanation concentration zone is 6-7, the temperature of the spray liquid is 75°C-80°C, and the concentration of diammonium phosphate in the spray liquid is 25%-40%; and / or, the pH of the spray liquid in the deamination and dust removal zone 1 is 6-6.5, the temperature of the spray liquid is 50°C-60°C, and the concentration of diammonium phosphate in the spray liquid is 10%-20%; and / or, the pH of the spray liquid in the deamination and dust removal zone 2 is 6-6.5, the temperature of the spray liquid is 50°C-55°C, and the concentration of diammonium phosphate in the spray liquid is 1%-10%; and / or, the absorption temperature of the deep ammonia removal tower is 35°C-45°C, the pH of the spray liquid is 2-3, and the concentration of ammonium sulfate in the spray liquid is 15%-25%.

[0019] Compared with the prior art, the fluidized bed hydrocyanic acid process gas resource deammoniation dust removal purification system and method provided by the present invention has the following beneficial effects:

[0020] 1. The resource-based deamination and dust removal purification system provided by the present invention adopts a composite deamination and decyanation and dust removal technology to rapidly cool, deaminate and remove dust from the process gas while decyanating and concentrating the rich liquid in the bottom of the tower, recovering ammonia and catalytic particles in the ultra-clean removal of hydrocyanic acid process, with high resource utilization rate;

[0021] 2. The deamination and decyanation dust removal tower provided by the present invention is divided into three functional zones, and the temperature and pH value of each functional zone are independently controlled. The lower section is a quenching and decyanation concentration zone, and its main functions are to quench the process gas, strip the hydrocyanic acid dissolved in the absorption liquid, concentrate the absorption liquid, and increase the concentration of the discharged rich liquid. The middle section and the upper section are both deamination and dust removal zones, which can completely remove the catalyst particles and more than 95% of the ammonia in the process gas;

[0022] 3. The rich liquid discharged from the bottom of the deamination tower is pre-treated by microfiltration and deep degassing before entering the rich liquid analysis tower to recover the solid catalyst, while reducing the risk of blockage of the rich liquid analysis tower and extending the operation cycle of the rich liquid analysis tower;

[0023] 4. The ammonia concentrator installed on the top of the rich liquid analysis tower is a special semi-condensing condenser with gas phase extraction and liquid phase reflux. It can control the condensation temperature, reflux ratio and extraction volume, simplify the control process, reduce cooling consumption, and reduce the overall energy consumption of the system;

[0024] 5. By using the resource-based ammonia removal and dust removal purification system and method provided by the present invention, the ammonia content in the purified process gas is less than 3ppm, the dust content is less than 1ppm, the loss of hydrocyanic acid in the separation process is small, the yield is greater than 99.5%, the ammonia content of the produced water is less than 50ppm, and the purity of the produced ammonia is greater than 99.9%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0026] Figure 1 This is a schematic structural diagram of the resource-based ammonia removal and dust removal purification system provided by the present invention.

[0027] Figure 2 A schematic diagram of the structure of a deamination tower provided by the present invention;

[0028] Figure 3 A schematic diagram of the structure of the distributed liquid receiving tray provided by the present invention;

[0029] Figure 4 A schematic diagram of the structure of a deep ammonia removal tower provided by the present invention;

[0030] Figure 5 A schematic diagram of the structure of the rich liquid analysis device provided by the present invention;

[0031] Figure 6 This is a schematic structural diagram of the ammonia concentrator provided by the present invention.

[0032] Description of Figure Numbers:

[0033] 100—deamination tower; 101—first gas phase inlet; 102—first gas phase outlet;

[0034] 103—first-level spray layer; 104—first-level spray liquid circulation pipeline; 105—first-level circulation pump; 106—first-zone distributed liquid receiving tray;

[0035] 107—secondary spray layer; 108—secondary spray liquid circulation pipeline; 109—secondary circulation pump; 110—secondary cooler; 111—second zone distributed liquid receiving tray;

[0036] 112—third-stage spray layer; 113—third-stage spray liquid circulation pipeline; 114—third-stage circulation pump; 115—third-stage cooler;

[0037] 116—gas distributor; 117—demister;

[0038] 118—bottom liquid receiving tray; 119—gas distribution pipe; 120—downcomer; 121—cap; 122—sunken circulating liquid buffer zone;

[0039] 200—deep ammonia removal tower; 201—second gas phase inlet; 202—purified gas outlet;

[0040] 203—fourth-stage spray layer; 204—fourth-stage spray liquid circulation pipeline; 205—fourth-stage circulation pump; 206—sulfuric acid absorbent delivery pipeline;

[0041] 300—rich liquid microfiltration solid removal separator; 301—rich liquid heat exchanger;

[0042] 400—rich liquid degassing tank; 401—third gas phase outlet; 402—third liquid phase outlet;

[0043] 500—rich liquid analysis tower; 501—feed inlet; 502—fourth gas phase outlet; 503—lean liquid outlet; 504—liquid phase reflux inlet; 505—lean liquid cooler;

[0044] 600—ammonia concentrator; 601—cooling medium inlet; 602—cooling medium outlet; 603—fifth gas phase inlet; 604—ammonia concentrated gas outlet; 605—fifth liquid phase outlet; 606—liquid phase overflow outlet; 607—cooling pipe;

[0045] 700—ammonia distillation tower; 701—ammonia concentrate gas inlet; 702—high-purity ammonia gas outlet; 703—drain outlet; 704—water discharge pipeline; 705—water recycling pipeline;

[0046] 800—Hydrogen cyanide process gas inlet pipeline. DETAILED DESCRIPTION

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0048] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0049] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0050] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0052] Example 1

[0053] like Figure 1 As shown, the present invention provides a fluidized bed hydrocyanic acid process gas resource deammoniation and dust removal purification system, including: a deammoniation, dust removal and decyanation unit and a rich liquid treatment unit. The above two units are described below respectively.

[0054] (1) Deamination, dust removal and decyanation unit

[0055] The deamination, dust removal and decyanation unit involves decyanation, dust removal and ammonia removal of hydrocyanic acid process gas, and comprises: a deamination tower 100 and a deep ammonia removal tower 200 which are sequentially connected according to the flow direction of the hydrocyanic acid process gas.

[0056] The deammonification tower 100 is used to remove dust and ammonia from the hydrocyanic acid process gas, and to concentrate and decyanate the absorption liquid, while the deep deammonification tower 200 is used to deeply remove ammonia from the gas after dust and ammonia removal. Figure 2 As shown:

[0057] The deamination tower 100 is provided with a first gas phase inlet and a first gas phase outlet, and the first gas phase inlet is connected to the hydrogen cyanide process gas inlet pipeline 800 .

[0058] Three functional areas are arranged in the deamination tower 100: from bottom to top, they are a rapid cooling decyanation concentration area, a deamination dust removal area 1, and a deamination dust removal area 2. The primary spray mechanism in the rapid cooling decyanation concentration area includes a multi-layer primary spray layer 103, the secondary spray mechanism in the deamination dust removal area 1 includes a multi-layer secondary spray layer 107, and the tertiary spray mechanism in the deamination dust removal area 2 includes a multi-layer tertiary spray layer 112.

[0059] The circulating spray liquid in the deammonification tower 100 uses monoammonium phosphate as the absorbent (the main component of the lean liquid). The monoammonium phosphate absorbs ammonia and reacts with it to form diammonium phosphate (the main component of the rich liquid). The operating temperature and the concentration of the spray absorption liquid in the three functional zones are reduced in sequence to meet the functional objectives of each zone.

[0060] Preferably, 2 to 3 primary spray layers 103 are arranged in the rapid cooling decyanation concentration zone, 3 to 4 secondary spray layers 107 are arranged in the first deamination and dust removal zone, and 2 to 4 tertiary spray layers 112 are arranged in the second deamination and dust removal zone.

[0061] More preferably, the distances between adjacent spray layers in the rapid cooling decyanation concentration zone, the first deamination and dust removal zone, and the second deamination and dust removal zone are all 800 mm to 1500 mm.

[0062] The deammonification, dust removal and decyanation unit further includes a primary spray liquid circulation pipeline 104 , a secondary spray liquid circulation pipeline 108 and a tertiary spray liquid circulation pipeline 113 .

[0063] The two ends of the primary spray liquid circulation pipeline 104 are respectively connected to the circulating spray liquid outlet at the bottom of the quenching decyanation concentration zone (it can also be the tower kettle outlet, such as Figure 2 The primary spray liquid circulation pipeline 104 is provided with a primary circulation pump 105. The primary spray liquid in the quenching decyanation concentration zone is pressurized by the primary circulation pump 105 and then sent to the primary spray layer 103 for circulation spraying.

[0064] The two ends of the secondary spray liquid circulation pipeline 108 are respectively connected to the circulating spray liquid outlet at the bottom of the deamination and dust removal zone 1 and the secondary spray layer 107. The secondary spray liquid circulation pipeline 108 is provided with a secondary circulation pump 109 and a secondary cooler 110. The secondary spray liquid in the deamination and dust removal zone 1 is pressurized by the secondary circulation pump 109 and cooled by the secondary cooler 110, and then sent to the secondary spray layer 107 for circulating spraying.

[0065] The two ends of the tertiary spray liquid circulation pipeline 113 are respectively connected to the circulating spray liquid outlet at the bottom of the second deamination and dust removal zone and the tertiary spray layer 112. The tertiary spray liquid circulation pipeline 113 is provided with a tertiary circulation pump 114 and a tertiary cooler 115. The tertiary spray liquid in the second deamination and dust removal zone is pressurized by the tertiary circulation pump 114 and cooled by the tertiary cooler 115, and then sent to the tertiary spray layer 112 for circulating spraying.

[0066] In some embodiments, a gas distributor 116 is further provided in the deamination tower 100 . The gas distributor 116 is disposed between the first gas phase inlet 101 and the quenching decyanation concentration zone to uniformly distribute the hydrocyanic acid process gas entering the deamination tower 100 .

[0067] Preferably, the gas distributor 116 is a tubular structure, the height of the distribution pipe of the gas distributor 116 is 50 mm to 150 mm, and the ventilation area of ​​the distribution pipe is 1 / 7 to 1 / 4 of the cross-sectional area of ​​the deamination tower 100.

[0068] In some embodiments, a distributed liquid receiving tray for receiving the spray liquid is further provided in the deamination tower 100 .

[0069] A distributed liquid receiving tray is arranged between the rapid cooling decyanation concentration zone and the deamination and dust removal zone 1, that is, the distributed liquid receiving tray is arranged at the bottom of the deamination and dust removal zone 1, and is used to receive the secondary circulating spray liquid in the deamination and dust removal zone 1, which is called the zone 1 distributed liquid receiving tray 106. The zone 1 distributed liquid receiving tray 106 is connected to the secondary spray liquid circulation pipeline 108 through the circulating spray liquid outlet of the deamination and dust removal zone 1, so that the received secondary circulating spray liquid is circulated and sprayed.

[0070] A distributed liquid receiving tray is also arranged between the deamination dust removal zone 1 and the deamination dust removal zone 2, that is, arranged at the bottom of the deamination dust removal zone 2, for receiving the tertiary circulating spray liquid in the deamination dust removal zone 2, called the zone 2 distributed liquid receiving tray 111. The zone 2 distributed liquid receiving tray 111 is connected to the tertiary spray liquid circulation pipeline 113 through the circulating spray liquid outlet of the deamination dust removal zone 2, so that the received tertiary circulating spray liquid is circulated and sprayed.

[0071] In some embodiments, the structures of the first zone distributed liquid receiving tray 106 and the second zone distributed liquid receiving tray 111 may be the same or different, but in this embodiment, the two are described as being the same. Figure 3 As shown, the specific structure includes: a bottom liquid receiving tray 118, a plurality of gas distribution pipes 119, a plurality of downcomers 120, a plurality of caps 121 and a sunken circulating liquid buffer zone 122.

[0072] The bottom liquid receiving tray 118 is provided with a plurality of ventilation holes distributed at intervals, and the opening rate of the ventilation holes is preferably in the range of 30% to 50%.

[0073] The gas distribution pipe 119 is vertically arranged on the bottom liquid receiving tray 118 and is connected to the vents one by one. More specifically, the inlet end of the gas distribution pipe 119 is connected to the vents, and the outlet end of the gas distribution pipe 119 is set in a direction away from the bottom of the deamination tower 100.

[0074] The height of the gas distribution pipe 119 is preferably 200 mm to 600 mm.

[0075] The cap cover 121 is disposed on the top of the gas distribution pipe 119 and maintains a certain gap with the gas distribution pipe 119 . The number of the cap covers 121 corresponds to the number of the gas distribution pipes 119 .

[0076] Preferably, the cap 121 is flat or ridge-shaped, and the equivalent diameter of the cap 121 is 1.1 to 1.3 times the diameter of the gas distribution pipe 119, and the vertical spacing from the top of the gas distribution pipe 119 is 20 mm to 80 mm.

[0077] The downcomers 120 are preferably disposed close to the inner wall of the deamination tower 100, and the number thereof is preferably 1 to 6.

[0078] The top of the downcomer 120 is lower than the top of the gas distribution pipe 119, and the vertical distance between the top of the downcomer 120 and the top of the gas distribution pipe 119 is preferably 50 mm to 150 mm.

[0079] The vertical distance between the bottom of the downcomer 120 and the spray layer closest to the bottom of the distributed liquid receiving tray is 50 mm to 200 mm.

[0080] The sinking circulating liquid buffer 122 is arranged between the bottom liquid receiving tray 118 and the inner wall of the tower. The diameter of the sinking circulating liquid buffer 122 is 1.5 to 3 times the diameter of the downcomer 119, and the height is 200 mm to 500 mm.

[0081] In some embodiments, a demister 117 is further provided in the deammoniation tower 100. The demister 117 is disposed at the top of the deammoniation tower 100, namely between the second deammoniation and dust removal zone and the first gas phase outlet 102, for removing free liquid droplets entrained in the gas.

[0082] Preferably, the demister 117 includes three layers, namely, from bottom to top, a two-channel baffle demister, a three-channel baffle demister and a wire mesh demister, which can efficiently remove free droplets entrained in the gas.

[0083] A second gas phase inlet 201 is provided at the bottom of the deep ammonia removal tower 200, and the second gas phase inlet 201 is connected to the first gas phase outlet 102 of the deammonification tower 100, and the process gas after dust and ammonia removal is input into the deep ammonia removal tower 200 for deep ammonia removal.

[0084] A purified gas outlet 202 is provided at the top of the deep ammonia removal tower 200 .

[0085] The deep ammonia removal tower 200 includes a gas distributor 106 , a four-stage spray mechanism and a demister 117 which are arranged in sequence from bottom to top. The four-stage spray mechanism includes a multi-layer four-stage spray layer 203 .

[0086] The gas distributor 106 in the deep ammonia removal tower 200 has the same structure as the gas distributor 106 in the deammonification tower 100, and will not be described in detail here.

[0087] The demister 117 in the deep ammonia removal tower 200 has the same structure as the demister 117 in the deammonification tower 100, both of which are three-layered, and will not be described in detail here.

[0088] In some embodiments, 3 to 5 four-stage spray layers 203 are arranged in the deep ammonia removal tower 200, and the distance between two adjacent four-stage spray layers 203 is preferably 800 mm to 1500 mm.

[0089] In some embodiments, the deamination, dust removal and decyanation unit also includes a four-stage spray liquid circulation pipeline 204, and both ends of the four-stage spray liquid circulation pipeline 204 are respectively connected to the circulating spray liquid outlet of the deep ammonia removal tower 200 and the four-stage spray layer 203. A four-stage circulation pump 205 is provided on the four-stage spray liquid circulation pipeline 204. The four-stage spray liquid in the deep ammonia removal tower 200 is pressurized by the four-stage circulation pump 205 and sent to the four-stage spray layer 203 for circulation spraying.

[0090] In some embodiments, the deamination, dust removal and cyanide removal unit further includes a sulfuric acid absorbent delivery pipeline 206 for delivering the sulfuric acid absorbent required for deep ammonia removal to the deep ammonia removal tower 200 .

[0091] Preferably, the sulfuric acid absorbent delivery pipeline 206 is directly connected to the fourth-stage spray liquid circulation pipeline 204, and the new sulfuric acid absorbent is mixed with the fourth-stage circulating spray liquid and then enters the fourth-stage spray layer 203 for circulating spraying.

[0092] (II) Rich liquid treatment unit

[0093] The rich liquid treatment unit involves the desolidification, decyanation, analysis and ammonia distillation recovery of the rich liquid generated in the process of dedusting and ammonia removal of the hydrocyanic acid process gas, and finally obtains high-purity ammonia gas.

[0094] like Figure 1 As shown, the unit includes: a rich liquid microfiltration solid removal separator 300, a rich liquid degassing tank 400, a rich liquid analysis device and an ammonia distillation tower 700 which are sequentially connected according to the flow direction of the rich liquid discharged from the deammonification tower 100.

[0095] The rich liquid microfiltration solid removal separator 300 is used to separate the catalyst in the rich liquid. The rich liquid degassing tank 400 is used to remove residual gases such as hydrocyanic acid entrained in the rich liquid. The rich liquid analysis device is used to analyze and decompose the diammonium phosphate in the rich liquid to obtain ammonia concentrated gas and monoammonium phosphate absorbent that can be recycled to the deammonification tower 100. The ammonia distillation tower 700 is used to distill the ammonia concentrated gas to obtain high-purity ammonia gas. Specifically:

[0096] like Figure 4 As shown, the rich liquid microfiltration de-solidification separator 300 is provided with an inlet, a solid catalyst outlet and a liquid phase outlet. The inlet of the rich liquid microfiltration de-solidification separator 300 is connected to the primary spray liquid circulation pipeline 104. The circulating spray liquid (rich liquid) that completes the decyanation process in the rapid cooling decyanation concentration zone is discharged into the rich liquid microfiltration de-solidification separator 300 to separate and recover the solid catalyst in this part of the circulating spray liquid (rich liquid).

[0097] The liquid phase outlet of the rich liquid microfiltration solid removal separator 300 is connected to the inlet of the rich liquid degassing tank 400, and the rich liquid after solid removal enters the rich liquid degassing tank 400.

[0098] The rich liquid degassing tank 400 is provided with an inlet, a third gas phase outlet 401 and a third liquid phase outlet 402. The desolidified rich liquid enters the rich liquid degassing tank 400 to remove gases such as hydrogen cyanide that may be entrained.

[0099] The third gas phase outlet 401 of the rich liquid degassing tank 400 is connected to the second gas phase inlet 201 of the deep ammonia removal tower 200, and the gas removed from the rich liquid is mixed with the preliminary purified process gas discharged from the ammonia removal tower 100 and then enters the deep ammonia removal tower 200 for deep ammonia removal.

[0100] The third liquid phase outlet 402 of the rich liquid degassing tank 400 is connected to the rich liquid analysis device, and the degassed rich liquid is sent to the rich liquid analysis device for analysis.

[0101] Preferably, the rich liquid degassing tank 400 can be a horizontal degassing tank or a vertical degassing tank.

[0102] In some embodiments, a rich liquid heat exchanger 301 is further provided on the connecting pipeline between the liquid phase outlet of the rich liquid microfiltration desolidification separator 300 and the inlet of the rich liquid degassing tank 400, and the rich liquid from which the catalyst has been removed enters the rich liquid degassing tank 400 after heat exchange in the rich liquid heat exchanger 301.

[0103] Combination Figure 1 and Figure 5 As shown, the rich liquid analysis device includes a rich liquid analysis tower 500 and an ammonia concentrator 600 with a special structure arranged on the top of the rich liquid analysis tower 500. The ammonia concentrator 600 serves as a tower top semi-condenser of the rich liquid analysis tower 500, and is used to cool and separate water vapor and concentrate ammonia. Specifically:

[0104] The top of the rich liquid analysis tower 500 is provided with a fourth gas phase outlet 502 , a feed inlet 501 and a liquid phase reflux inlet 504 , and the bottom is provided with a lean liquid outlet 503 .

[0105] Preferably, the rich liquid analysis tower 500 adopts a directional solid valve tray structure, which can reduce the tower pressure drop and avoid tower blockage. The theoretical number of plates of the rich liquid analysis tower 500 is between 32 and 36.

[0106] The lean liquid outlet 503 is connected to the secondary spray liquid circulation pipeline 108 and / or the tertiary spray liquid circulation pipeline 113. The rich liquid is analyzed and enriched in the rich liquid analysis tower 500, and the monoammonium phosphate (lean liquid) obtained is extracted and returned to the deammonification tower 100 as an absorbent to circulate and absorb ammonia.

[0107] In some embodiments, a lean liquid cooler 505 is further provided on the connecting pipeline of the lean liquid outlet 503 for cooling the lean liquid for return to the deamination tower 100 .

[0108] In some embodiments, in combination Figure 5 and Figure 6As shown, a liquid phase area and a cooling area are arranged from bottom to top in the shell of the ammonia concentrator 600. A cooling pipe 607 is arranged in the cooling area. The cooling pipe 607 is preferably a U-shaped cooling pipe. The liquid phase area is a temporary storage space for condensed liquid.

[0109] The shell of the ammonia concentrator 600 is provided with a cooling medium inlet 601 , a cooling medium outlet 602 , a fifth gas phase inlet 603 , an ammonia concentrated gas outlet 604 , a fifth liquid phase outlet 605 and a liquid phase overflow outlet 606 .

[0110] Specific:

[0111] The fifth liquid phase outlet 605 of the ammonia concentrator 600 is disposed at the bottom of the shell and is connected to the liquid phase reflux port 504 of the rich liquid analysis tower 500 .

[0112] The liquid phase overflow outlet 606 is disposed on the shell side wall corresponding to the liquid phase region and is connected to the feed inlet 501 of the rich liquid analysis tower 500 .

[0113] Preferably, the liquid phase overflow outlet 606 is disposed at the shell side wall at a height of 1 / 4 to 2 / 7 of the tangent line from the bottom of the ammonia concentrator 600 .

[0114] Preferably, the position of the liquid phase overflow outlet 606 is lower than the position of the bottom of the cooling pipe 607, and the vertical distance between the liquid phase overflow outlet 606 and the bottom of the cooling pipe 607 is 200 mm to 500 mm.

[0115] The cooling medium inlet 601, the cooling medium outlet 602 and the fifth gas phase inlet 603 are all arranged on the shell corresponding to the cooling zone, and the inlet and outlet of the cooling pipe 607 are respectively connected to the cooling medium inlet 601 and the cooling medium outlet 602. At the same time, the feed port of the rich liquid analysis tower 500 is connected to the liquid phase outlet of the rich liquid degassing tank 400 through the cooling pipe 607, that is, the cooling medium inlet 601 is connected to the third liquid phase outlet 402 of the rich liquid degassing tank 400, and the cooling medium outlet 602 is connected to the feed port 501 of the rich liquid analysis tower 500. The degassed rich liquid is used as the cooling medium through the cooling pipe 607. The cooling medium inlet 601 enters the cooling pipe 607. At the same time, the ammonia and water vapor produced by the decomposition of the rich liquid in the rich liquid analysis tower 500 rise and enter the cooling zone of the ammonia concentrator 600 from the fourth gas phase outlet 502 at the top of the tower. The water vapor is cooled into liquid water and falls into the liquid phase area (at this time, the cooled liquid will still contain a small amount of ammonia), and then returns to the rich liquid analysis tower 500 through the fifth liquid phase outlet 605 or the liquid phase overflow outlet 606. The ammonia will not be cooled, but will remain in a gaseous state and be discharged through the ammonia concentrated gas outlet 604 at the top of the ammonia concentrator 600 to enter the ammonia distillation tower 700.

[0116] Preferably, the fifth gas phase inlet 603 is disposed on the shell side wall at a height of 1 / 2 to 3 / 5 of the tangent line height from the bottom of the ammonia concentrator 600 .

[0117] The ammonia concentrated gas outlet 604 is disposed at the top of the shell of the ammonia concentrator 600 and is connected to the ammonia distillation tower 5 to send the ammonia concentrated gas into the ammonia distillation tower 700 for distillation.

[0118] like Figure 1 As shown, an ammonia concentrated gas inlet 701 is provided on the side wall of the ammonia distillation tower 700, a high-purity ammonia gas outlet 702 is provided on the top, and a water outlet 703 is provided on the bottom.

[0119] Preferably, the ammonia distillation tower 700 is a conventional plate tower or a packed tower, and the number of theoretical plates of the ammonia distillation tower 700 is 8-10.

[0120] In some embodiments, the rich liquid treatment unit further includes a water discharge pipeline 704 connected to the water outlet 703 .

[0121] In some embodiments, the rich liquid treatment unit also includes a water recycling pipeline 705, the inlet of the water recycling pipeline 705 is connected to the drain outlet 703, and the outlet of the water recycling pipeline 705 is connected to the secondary spray liquid circulation pipeline 108 and / or the tertiary spray liquid circulation pipeline 113, so that the water obtained by distillation is recycled to the deamination tower 100.

[0122] In some embodiments, the rich liquid heat exchanger 301, the secondary cooler 110, the tertiary cooler 115, and the lean liquid cooler 505 may be shell and tube heat exchangers or spiral plate heat exchangers, preferably spiral plate heat exchangers.

[0123] Example 2

[0124] Based on Example 1, this example provides a fluidized bed hydrocyanic acid process gas purification method using the above-mentioned resource-based deamination and dust removal purification system, including two major steps of deamination, dust removal, decyanation and rich liquid treatment of the hydrocyanic acid process gas:

[0125] (i) The steps of ammonia removal, dust removal and cyanide removal are briefly described as follows: the dusty and ammonia-containing hydrocyanic acid process gas enters the deamination tower 100, and flows from bottom to top through the rapid cooling decyanide concentration zone, the deamination dust removal zone 1 and the deamination dust removal zone 2 to remove dust and ammonia from the process gas, and the absorption liquid is concentrated to remove cyanide. After the dust removal and ammonia removal, the process gas enters the deep deamination tower 200, and is countercurrently contacted with the sulfuric acid spray liquid to complete the deep deamination, thereby obtaining the purified process gas that can be discharged.

[0126] The above steps are explained in detail in combination with the devices in the deamination, dust removal and decyanation unit:

[0127] (1) Decyanation, dust removal and ammonia removal steps performed in the deamination tower 100:

[0128] The process principles involved in this step are:

[0129] Phosphoric acid (monoammonium) is used to absorb ammonia and analyze. The circulating absorbents for phosphoric acid to absorb ammonia are monoammonium phosphate (the main component of the lean solution) and diammonium phosphate (the main component of the rich solution). This is because monoammonium phosphate is stable and not easy to decompose and analyze, while diacidic acid is relatively stable at temperatures below 120°C, and can quickly decompose into monoammonium phosphate and ammonia when the temperature is above 160°C.

[0130] The reactions that occur during phosphoric acid absorption of ammonia are shown in the following equations ① and ②, and the reaction that occurs during the analytical process is shown in equation ③.

[0131] NH3+H3PO4→NH4H2PO4①

[0132] NH3+NH4H2PO4→(NH4)2HPO4②

[0133] (NH4)2HPO4→NH3+NH4H2PO4③

[0134] The technological principle of decyanation of absorption liquid is as follows: utilizing the high temperature of process raw gas, the high temperature gas and the finely dispersed absorption spray droplets come into rapid countercurrent contact, vaporizing the hydrocyanic acid contained therein, reducing the hydrocyanic acid content in the primary circulation spray liquid and the extracted rich liquid, avoiding the risk of polymerization during the rich liquid analysis process, and improving the yield of hydrocyanic acid.

[0135] The dusty and ammonia-containing hydrocyanic acid process gas at a temperature of 200°C to 250°C produced by the upstream fluidized bed reaction system enters the deamination tower 100 through the first gas phase inlet 101, and after being distributed by the gas distributor 116, it rises uniformly in the cross section of the entire deamination tower 100 and enters the quenching decyanation concentration zone, and contacts the primary circulating spray liquid in countercurrent for mass and heat transfer. The micro-scale droplets contact the high-temperature gas, and part of the water and trace dissolved hydrocyanic acid contained in it are instantly vaporized by heat and enter the gas phase. The catalyst particles in the gas phase are eluted by the spray liquid and enter the liquid phase. The phosphate concentration of the spray liquid increases, and the hydrocyanic acid is stripped and removed. The process gas temperature is also reduced to the range of 75°C to 80°C, and the catalyst particles entrained by the process gas are humidified and precipitated by the spray liquid into the spray liquid. The process gas after quenching and dust removal continues to rise, and enters the deamination and dust removal zone 1 through the gas distribution pipe of the distributed liquid receiving plate 106 in the first zone to continue deamination and dust removal.

[0136] The primary circulating spray liquid after decyanation is pressurized by the primary circulating pump 105 and then circulated and sprayed. In order to improve the decyanation efficiency of the spray liquid, the spray particle size of the primary circulating spray liquid is controlled at 50μm to 200μm, the temperature of the primary circulating liquid is controlled between 75°C and 80°C, and the pH value is controlled between 6 and 7. If the pH value is too high, it is easy to cause polymerization of hydrocyanic acid and ammonia. If the pH value is lower than this range, the acid content is too high and the utilization rate of the absorption liquid is low.

[0137] The concentration of diammonium phosphate in the primary spray liquid is controlled within the range of 25%-40%. If the concentration is too high, it is easy to cause crystallization and blockage, and the absorption efficiency is low; if the concentration is too low, the energy consumption of analysis and distillation is high.

[0138] The process gas entering the second deamination and dust removal zone contacts the secondary spray liquid in countercurrent to remove ammonia and dust. The secondary spray liquid is pressurized by the secondary circulation pump 109 and circulated and cooled by the secondary cooler 110. The spray particle size of the secondary spray liquid is controlled between 100 μm and 500 μm, and the temperature is controlled between 50°C and 60°C. The ammonia absorption efficiency is improved while reducing the amount of hydrocyanic acid dissolved in the liquid phase. The pH value of the secondary spray liquid is controlled between 6 and 6.5, and the concentration of diammonium phosphate in the absorption liquid is controlled within the range of 10% to 20% to reduce the surface tension of the secondary spray absorption liquid and improve the ammonia absorption efficiency and dust removal efficiency.

[0139] The lean liquid obtained by the analysis in the rich liquid analysis tower 500 is added from the inlet of the secondary cooler 110 to be diluted and dissolved into the secondary spray liquid. In addition, since the process gas is saturated with water when leaving the rapid cooling decyanation concentration zone, some water will be precipitated after being cooled in contact with the low-temperature circulating spray liquid in the deamination and dust removal zone 1, which will cause the liquid level on the distributed liquid receiving tray 106 in the zone 1 to rise. When the liquid level exceeds the top of the downcomer 120, it will overflow into the downcomer 120 and enter the rapid cooling decyanation concentration zone through the downcomer 120 to supplement the reduction of the primary circulating liquid caused by evaporation and external discharge of the rich liquid.

[0140] After the process gas completes the main deamination and dust removal in the deamination and dust removal zone 1, it enters the deamination and dust removal zone 2 through the gas distribution pipe of the distributed liquid receiving plate 111 of the zone 2 to continue deamination and deep dust removal. The partially analyzed lean liquid is added from the inlet of the third-stage circulation pump 114 (or the inlet of the third-stage cooler 115), and after being pressurized by the third-stage circulation pump 114 and cooled by the third-stage cooler 115, it enters the third-stage spray layer 112 to spray and absorb the process gas.

[0141] The concentration of diammonium phosphate in the tertiary spray liquid is controlled between 1% and 10%, and the temperature is controlled between 50°C and 55°C. While controlling the solubility of hydrocyanic acid in the liquid phase, the absorption efficiency of ammonia is improved. The pH value of the tertiary circulating spray liquid is controlled between 6 and 6.5.

[0142] The process gas after deamination and dust removal rises and passes through the three-layer demister 117 for deep demisting, and then enters the deep deamination tower 200 for deep deamination.

[0143] (2) The deep ammonia removal tower 200 performs the steps of deep ammonia removal:

[0144] The process principle of deep deammoniation is that sulfuric acid reacts with ammonia to generate ammonium sulfate. The reaction formula is shown in the following equation ④:

[0145] 3NH3+2H2SO4→(NH4)2SO4④

[0146] The dust content of the process gas after purification by the deamination tower 100 is less than 3mg / m 3 , reaching the ultra-clean standard and meeting the downstream process requirements. However, due to the weak acidity of phosphoric acid, the ammonia content in the process gas can only reach less than 50 mg / m 3 , which cannot meet the downstream process requirements, so the process gas purified by the deamination tower 100 enters the deep deamination tower 200 for further deamination and purification.

[0147] After preliminary purification, the process gas enters the deep deammoniation tower 200, and after being distributed by the gas distributor 116, it rises uniformly in the cross section of the deep deammoniation tower 200 and contacts the fourth-level spray liquid sprayed from the fourth-level spray layer 203 in countercurrent. The trace ammonia contained in the process gas is absorbed by the sulfuric acid spray liquid to form ammonium sulfate. After thorough deammoniation, the process gas rises and enters the downstream process after being defogged by the demister 117. The ammonia content in the process gas after purification by the deep deammoniation tower 200 is less than 3mg / m 3 , which can be used as purified hydrocyanic acid process gas to enter the downstream reaction device.

[0148] The fourth-stage spray liquid is pressurized by the fourth-stage circulation pump 205 and then circulated and sprayed, and at the same time, part of the ammonium sulfate solution is extracted to recover the ammonium sulfate product.

[0149] In order to achieve the purpose of deep deamination, the absorption temperature of the deep deamination tower 200 is controlled at 35°C to 45°C, the pressure is 0.005 to 0.05 MPa (g), the pH is controlled between 2 and 3, and the concentration of ammonium sulfate in the four-stage circulating spray liquid is controlled between 15% and 25%.

[0150] Supplementary sulfuric acid required for deep desulfurization is added from the inlet of the fourth-stage circulation pump 205.

[0151] (ii) The rich liquid treatment steps are briefly described as follows: the rich liquid in the bottom of the deammonification tower 100 enters the rich liquid microfiltration solid removal separator 300, the rich liquid after the catalyst particles are removed is subjected to heat exchange and temperature rise and then enters the rich liquid degassing tank 400, the rich liquid after the trace acid gases such as hydrocyanic acid are removed then enters the rich liquid analysis device for analysis, the ammonia concentrated gas obtained by analysis enters the ammonia distillation tower 700 for distillation, and finally obtains high-purity ammonia gas.

[0152] The above steps are described in detail in conjunction with the devices in the rich liquid treatment unit:

[0153] (3) Rich liquid desolidification step:

[0154] While the primary spray liquid is circulating and spraying, part of the primary circulating liquid is extracted from the outlet of the primary circulating pump 105 (or the rich liquid in the bottom of the deamination tower 100 is extracted) as rich liquid and enters the rich liquid microfiltration desolidification separator 300 for solid separation and purification, and the separated catalyst is recycled. The rich liquid after solid removal is sent to the rich liquid degassing tank 400 after heat exchange and temperature increase in the rich liquid heat exchanger 301.

[0155] (4) Rich liquid degassing step:

[0156] The rich liquid after solid removal enters the rich liquid degassing tank 400 to remove gases such as hydrocyanic acid that may be entrained. The removed gas is discharged from the third gas phase outlet 401 at the top, mixed with the preliminary purified process gas discharged from the deamination tower 100, and then enters the deep deamination tower 200 for deamination.

[0157] The degassed rich liquid is discharged from the third liquid phase outlet 402 at the bottom and enters the ammonia concentrator 600 as a cooling medium, and is first heated by heat exchange with the top gas of the rich liquid analysis tower 500, and then enters the rich liquid analysis tower 500 for analysis.

[0158] The operating pressure of the rich liquid degassing tank 400 is 0.005-0.03 MPa(g), and the temperature is 100°C-110°C. If the temperature is too low, the degassing of the hydrocyanic acid is not complete, and if the temperature is too high, the decomposition of diammonium phosphate is likely to occur.

[0159] (5) Rich liquid desorption step:

[0160] The rich liquid enters the rich liquid analysis tower 500 from the fourth liquid phase inlet 501. After being heated by the rising steam in the tower, the diammonium phosphate is decomposed into monoammonium phosphate. The ammonia produced by the decomposition is discharged from the fourth gas phase outlet 502 at the top of the tower together with the rising water vapor and enters the ammonia concentrator 600. The operating temperature and pressure of the ammonia concentrator 600 are controlled so that part of the water is cooled into liquid while the ammonia remains in a gaseous state. The ammonia-containing cooling water is discharged from the fifth liquid phase outlet 605 at the bottom of the ammonia concentrator 600 as reflux back to the top of the tower. If the liquid level in the liquid phase zone exceeds the liquid phase overflow outlet 606, it overflows from the liquid phase overflow outlet 606 and returns to the inlet of the rich liquid analysis tower 500.

[0161] The monoammonium phosphate enriched in the bottom of the tower is extracted through the lean liquid outlet 503 as the absorption lean liquid, and after being cooled by the lean liquid cooler 505, it returns to the deammonification tower 100 to circulate and absorb ammonia.

[0162] In some embodiments, the operating conditions of the rich liquid analysis tower 500 are: the top pressure is 1.2-1.4 MPa (g), the top temperature is 170-190°C, the bottom temperature is 190°C-210°C, the feed temperature is 150-170°C, and the monoammonium phosphate concentration of the lean liquid obtained by analysis is 35%-50%.

[0163] In some embodiments, the operating temperature of the ammonia concentrator 600 is 140° C. to 160° C., and the concentration of the ammonia gas exhausted from the ammonia concentrator 600 is 26% to 35%.

[0164] (6) Ammonia concentrated gas distillation step:

[0165] The concentrated ammonia gas discharged from the ammonia concentrator 600 enters the ammonia distillation tower 700, and through distillation, the purity of the ammonia produced at the top of the tower is increased to more than 99.5%. Part of the water produced in the bottom of the tower is returned to the deammoniation tower 100, and part is discharged.

[0166] In some embodiments, the top pressure of the ammonia distillation tower 700 is controlled at 1.0-1.4 MPa(g), the feed temperature of the ammonia distillation tower 700 is 130°C-160°C, the top temperature is controlled at 140°C-150°C, and the bottom temperature is 185-200°C.

[0167] The purity of the ammonia product at the top of the tower is greater than 99.5%, and the ammonia content in the bottom water of the tower is less than 50ppm.

[0168] The following is a description of the resource-based deammoniation and dust removal purification system and method for hydrocyanic acid process gas in a fluidized bed provided by the present invention in conjunction with specific embodiments:

[0169] Example 3

[0170] (I) Fluidized bed hydrocyanic acid process reaction mixed gas parameters are shown in Table 1 below.

[0171] Table 1 Fluidized bed hydrocyanic acid process reaction mixed gas parameters

[0172]

[0173] (II) Structural setting of the fluidized bed hydrocyanic acid process gas resource deammoniation and dust removal purification system:

[0174] Deamination tower 100: the quenching decyanation concentration zone includes two primary spray layers 103, the deamination and dust removal zone 1 includes three secondary spray layers 107, and the deamination and dust removal zone 2 includes three tertiary spray layers 112.

[0175] The distributed liquid receiving pan 106 in zone 1 and the distributed liquid receiving pan 111 in zone 2 have the same structure: the opening rate range is 30%, the height of the gas distribution pipe 119 is 500 mm, the equivalent diameter of the cap 121 is 1.2 times the diameter of the gas distribution pipe 119, and the vertical spacing from the top of the gas distribution pipe 119 is 50 mm; 4 downcomers 120 are arranged, and the top of the downcomer 120 is 100 mm lower than the top of the gas distribution pipe 119; the diameter of the sunken circulating liquid buffer zone 122 is twice the diameter of the downcomer 120, and the height is 500 mm.

[0176] The height of the gas distribution pipe 119 is 100 mm, and the ventilation area of ​​the gas distributor 116 is 1 / 6 of the cross-sectional area of ​​the deamination tower 100 .

[0177] The number of the four-stage spray layers 203 in the four-stage spray mechanism in the deep ammonia removal tower 200 is 4.

[0178] (III) Setting of process operation parameters for resource-based deamination and dust removal:

[0179] (1) Operation parameters of the deamination tower 100:

[0180] The tower top pressure is 0.047MPa(g).

[0181] Rapid cooling and decyanation concentration zone: the temperature is 80°C, the pH value is 6.7, and the concentration of diammonium phosphate in the primary spray liquid is 35%.

[0182] Deamination and dust removal zone 1: The temperature is 57°C, the pH value is 6.5, and the concentration of diammonium phosphate in the secondary spray liquid is 25%.

[0183] Deamination and dust removal zone 2: The temperature is 53°C, the pH value is 6.0, and the concentration of diammonium phosphate in the tertiary spray liquid is 5%.

[0184] (2) Deep ammonia removal tower 200 operating parameters:

[0185] The temperature is 40°C, the pressure is 0.046MPa(g), the pH value is 2.5, and the concentration of diammonium phosphate in the three-stage spray circulation fluid is 16%

[0186] (3) Rich liquid degassing tank 400: temperature 105°C, pressure 0.01MPa(g)

[0187] (4) Rich liquid analysis tower 500: tower top pressure is 1.2 MPa(g), tower top temperature is 170°C, tower bottom temperature is 190°C, and feed temperature is 155°C;

[0188] (5) Ammonia concentrator 600: The temperature is 150°C and the concentration of the exhaust ammonia is 29%.

[0189] (6) Ammonia distillation tower 700: the tower top pressure is 1.2 MPa(g), the tower top temperature is 140°C, the tower bottom temperature is 190°C, and the feed temperature is 150°C.

[0190] The purification results are shown in Table 2.

[0191] Example 4

[0192] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0193] The temperature of the process reaction mixed gas is 230°C, and the temperature of the rapid cooling and decyanation concentration zone in the deammonification tower 100 is 78°C.

[0194] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0195] Example 5

[0196] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0197] The temperature of the process reaction mixed gas is 200°C, and the temperature of the rapid cooling and decyanation concentration zone in the deammonification tower 100 is 76°C.

[0198] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0199] Example 6

[0200] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0201] The pH value of the rapid cooling decyanation concentration zone in the deamination tower 100 is 7, and the pH value of the deep deamination tower 200 is 3.

[0202] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0203] Example 7

[0204] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0205] The operating temperature of the rich liquid degassing tank 400 is 108° C. and the pressure is 0.03 MPa(g).

[0206] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0207] Example 8

[0208] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0209] The top pressure of the rich liquid analysis tower 500 is 1.3 MPa(g), the top temperature is 180°C, the bottom temperature is 200°C, the feed temperature is 160°C, and the exhaust ammonia concentration of the ammonia concentrator 600 is 32%.

[0210] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0211] Example 9

[0212] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0213] The top pressure of the rich liquid analysis tower 500 was 1.4 MPa(g), the top temperature was 190°C, the bottom temperature was 210°C, the feed temperature was 170°C, and the temperature of the ammonia concentrator 600 was 160°C.

[0214] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0215] Example 10

[0216] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0217] The temperature of the ammonia concentrator 600 is 160° C., and the concentration of the exhaust ammonia gas is 26%.

[0218] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0219] Embodiment 11

[0220] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0221] The temperature of the ammonia concentrator 600 is 140° C., and the concentration of the exhaust ammonia gas is 35%.

[0222] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0223] Example 12

[0224] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0225] Except that the quenching decyanation concentration zone includes three primary spray layers 103, other device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0226] Example 13

[0227] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0228] Five four-stage spray layers 203 are arranged in the deep ammonia removal tower 200 .

[0229] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0230] Embodiment 14

[0231] The steps of this embodiment are basically the same as those of Embodiment 3, except that:

[0232] The ventilation area of ​​the gas distribution pipe 119 of the gas distributor 116 is 1 / 5 of the tower cross-sectional area.

[0233] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0234] Comparative Example 1

[0235] The steps of this comparative example are basically the same as those of Example 3, except that:

[0236] A cooler is provided on the primary spray liquid circulation pipeline 104, and the temperature of the rapid cooling decyanation concentration zone is 50°C.

[0237] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0238] Comparative Example 2

[0239] The steps of this comparative example are basically the same as those of Example 3, except that:

[0240] The ventilation area of ​​the gas distribution pipe 119 is 1 / 3 of the tower cross-sectional area.

[0241] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0242] Comparative Example 3

[0243] The steps of this comparative example are basically the same as those of Example 3, except that:

[0244] The bottom temperature of the rich liquid analysis tower 500 was 170°C, the top temperature was 150°C, and the temperature of the ammonia concentrator 600 was 140°C.

[0245] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0246] Comparative Example 4

[0247] The steps of this comparative example are basically the same as those of Example 3, except that:

[0248] The bottom temperature of the ammonia distillation tower 700 is 160°C, and the top temperature is 120°C.

[0249] The remaining device parameters and operating parameters are the same as those in Example 3. The purification results are shown in Table 2.

[0250] Table 2 Purification results of Examples 3-14 and Comparative Examples 1-4

[0251]

[0252] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Fluidized bed hydrocyanic acid process gas resource deammoniation dust removal purification system, It is characterized in that Including: deammoniation, dust removal, decyanation unit and rich liquid treatment unit; The deamination, dust removal and decyanation unit comprises: a deamination tower and a deep deamination tower which are connected in sequence according to the flow direction of the hydrocyanic acid process gas; The deamination tower is used to remove dust and ammonia from the hydrocyanic acid process gas, and simultaneously concentrate and decyanate the absorption liquid; The deep ammonia removal tower is used to deeply remove ammonia from the gas after ammonia removal; The rich liquid processing unit comprises: a rich liquid microfiltration desolidification separator, a rich liquid degassing tank, a rich liquid analysis device and an ammonia distillation tower which are connected in sequence according to the flow direction of the rich liquid discharged from the reactor of the deammoniation tower; The rich liquid microfiltration solid removal separator is used to separate the catalyst in the rich liquid; The rich liquid degassing tank is used to remove gases such as hydrocyanic acid remaining in the rich liquid; The rich liquid analysis device is used to analyze the rich liquid to obtain ammonia concentrated gas and monoammonium phosphate absorbent that can be recycled to the deammonification tower; The ammonia distillation tower is used to distill the ammonia concentrated gas discharged from the top of the rich liquid analysis tower to obtain high-purity ammonia gas.

2. The resource-based ammonia removal and dust removal purification system according to claim 1 is characterized in that: The deamination tower is composed of a quenching decyanation concentration zone, a deamination dust removal zone 1, and a deamination dust removal zone 2 from bottom to top; The deamination, dust removal and decyanation unit also includes a primary spray liquid circulation pipeline, a secondary spray liquid circulation pipeline and a tertiary spray liquid circulation pipeline; A primary spray mechanism is provided in the quenching decyanation concentration zone, and the primary spray mechanism is connected to the primary spray liquid circulation pipeline; A secondary spray mechanism is provided in the deamination and dust removal zone 1, and the secondary spray mechanism is connected to the secondary spray liquid circulation pipeline; A three-stage spray mechanism is provided in the second deamination and dust removal zone, and the three-stage spray mechanism is connected to the three-stage spray liquid circulation pipeline.

3. The resource-based ammonia removal and dust removal purification system according to claim 1 is characterized in that: The deamination, dust removal and decyanation unit also includes a four-stage spray liquid circulation pipeline; A four-stage spray mechanism is arranged in the deep ammonia removal tower, and the four-stage spray mechanism is connected to the four-stage spray liquid circulation pipeline.

4. The resource-based ammonia removal and dust removal purification system according to claim 1 is characterized in that: The rich liquid analysis device comprises a rich liquid analysis tower and an ammonia concentrator, wherein the ammonia concentrator is used to cool the gas discharged from the top of the rich liquid analysis tower to obtain liquid ammonia water and concentrated ammonia gas, and the ammonia concentrator has a built-in cooling pipe, the feed port of the rich liquid analysis tower is connected to the liquid phase outlet of the rich liquid degassing tank through the cooling pipe of the ammonia concentrator, and the gas phase outlet at the top of the rich liquid analysis tower is connected to the gas phase inlet of the ammonia concentrator; The liquid phase outlet at the bottom of the ammonia concentrator is connected to the liquid phase reflux port at the top of the rich liquid analysis tower; The ammonia concentrated gas outlet of the ammonia concentrator is connected to the gas phase inlet of the ammonia rectification tower.

5. The resource-based ammonia removal and dust removal purification system according to claim 4 is characterized in that: The shell of the ammonia concentrator is provided with a liquid phase zone and a cooling zone from bottom to top, the cooling zone is provided with the cooling pipe, and the inlet and outlet of the cooling pipe are respectively connected to the liquid phase outlet of the rich liquid degassing tank and the feed port of the rich liquid analysis tower; The gas phase inlet of the ammonia concentrator is arranged on the side wall of the shell corresponding to the cooling zone; The ammonia concentrated gas outlet of the ammonia concentrator is arranged at the top of the shell; A liquid phase overflow port is provided on the side wall of the shell corresponding to the liquid phase zone, and the liquid phase overflow port is connected to the feed port of the rich liquid analysis tower.

6. The resource-based ammonia removal and dust removal purification system according to claim 1 is characterized in that: The deamination tower is also provided with a distributed liquid receiving tray; The distributed liquid receiving tray is provided between the quenching decyanation concentration zone and the deamination and dust removal zone 1, and between the deamination and dust removal zone 1 and the deamination and dust removal zone 2; The distributed liquid receiving pan comprises a bottom liquid receiving pan and a sunken circulating liquid buffer zone disposed between the bottom liquid receiving pan and the inner side wall of the tower, a plurality of gas distribution pipes and a plurality of downcomers; The bottom liquid receiving tray is provided with a plurality of vent holes, and the plurality of vent holes are distributed at intervals; The gas distribution pipes are connected to the vent holes in a one-to-one correspondence; A cap is provided on the top of the gas distribution pipe, and a gap is provided between the cap and the top of the gas distribution pipe.

7. A method for resource-based deamination and dust removal of hydrocyanic acid process gas in a fluidized bed, using the resource-based deamination and dust removal purification system according to any one of claims 1 to 6, characterized in that: It includes the steps of removing ammonia, dust and cyanide from the hydrocyanic acid process gas and the step of rich liquid treatment; The ammonia removal, dust removal and cyanide removal steps include: The dusty and ammonia-containing hydrocyanic acid process gas enters the deamination tower, and flows through the quenching decyanation concentration zone, the deamination dust removal zone 1 and the deamination dust removal zone 2 from bottom to top in order to remove dust and ammonia from the process gas, and to carry out a concentration and decyanation process on the absorption liquid. After the dust removal and removal of more than 95% of ammonia, the process gas enters the deep deamination tower, and is countercurrently contacted with the spray liquid with sulfuric acid as the absorbent to complete the deep deamination, thereby obtaining the purified process gas that can be discharged; The rich liquid treatment step comprises: The decyanated rich liquid produced in the kettle of the deammonification tower is discharged into the rich liquid microfiltration desolidification separator for solid removal. After the catalyst particles are removed, the rich liquid enters the rich liquid degassing tank for degassing after heat exchange and temperature increase. The rich liquid from which residual acid gases such as hydrocyanic acid are further removed then enters the rich liquid analysis device for analysis. The ammonia concentrated gas obtained by analysis enters the ammonia distillation tower for distillation, and finally obtains high-purity ammonia gas.

8. The resource-based deamination and dust removal purification method according to claim 7, characterized in that: The rich solution treatment step further comprises: The rich liquid analysis device separates the lean liquid containing monoammonium phosphate and reuses it in the deammonification tower as an absorbent.

9. The resource-based deamination and dust removal purification method according to claim 7, characterized in that: The rich liquid discharged from the rich liquid degassing tank enters the cooling pipe in the ammonia concentrator as a cooling medium, exchanges heat with the gas discharged from the top of the rich liquid analysis tower to increase its temperature, and then enters the rich liquid analysis tower for analysis.

10. The resource-based deamination and dust removal purification method according to claim 7, characterized in that: The pH of the spray liquid in the quenching decyanation concentration zone is 6-7, the temperature of the spray liquid is 75° C.-80° C., and the concentration of diammonium phosphate in the spray liquid is 25%-40%; and / or, The pH of the spray liquid in the deamination and dust removal zone is 6-6.5, the temperature of the spray liquid is 50°C-60°C, and the concentration of diammonium phosphate in the spray liquid is 10%-20%; and / or, The pH of the spray liquid in the second deamination and dust removal zone is 6-6.5, the temperature of the spray liquid is 50° C.-55° C., and the concentration of diammonium phosphate in the spray liquid is 1%-10%; and / or, The absorption temperature of the deep ammonia removal tower is 35-45°C, the pH of the spray liquid is 2-3, and the concentration of ammonium sulfate in the spray liquid is 15%-25%.

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