Purification device and purification system for efficiently absorbing organic amine and ammonia nitrogen waste gas

Abstract

The utility model provides a purification device and purification system for efficiently absorbing organic amine and ammonia nitrogen waste gas, which comprises an absorption tower, an absorption liquid tank, a dosing device and a solid-liquid separation device, an absorption liquid spraying device is arranged in the absorption tower, the dosing device comprises a magnesium salt dosing device and a phosphoric acid or phosphate dosing device, and the solid-liquid separation device is arranged in the absorption tower. The dosing device is connected to a liquid medicine inlet of the absorption liquid tank, and a liquid medicine outlet of the absorption liquid tank is connected to the absorption liquid spraying device; a waste gas outlet and a discharge port are respectively formed in the top end and the bottom end of the absorption tower, a waste gas inlet is formed in the bottom of the side wall, and the discharge port is connected to the solid-liquid separation device; gas detection devices are mounted at the waste gas inlet and the waste gas outlet; a pH detection device is mounted on the absorption liquid tank; the purification system comprises at least one group of purification devices. By adopting the purification device and the purification system disclosed by the utility model, organic amine and ammonia nitrogen waste gas in the waste gas can be efficiently absorbed.

Description

Technical Field

[0001] The utility model belongs to the technical field of waste gas purification devices, and particularly relates to a purification device and a purification system for efficiently absorbing organic amine and ammonia nitrogen waste gas. Background Art

[0002] In the prior art, for the absorption of ammonia waste gas, water absorption is usually adopted, and in some cases, acidic agents are added for neutralization to carry out chemical reactions to form strong acid-weak base salts (ammonium salts or amine salts). This absorption method has poor removal effect, too frequent water replacement, and because there are reversible reactions, for example, the reaction between ammonia and water is a reversible reaction, it is easy for ammonia water in water to form a certain concentration of vapor pressure, and the concentration in the corresponding gas phase exceeds the emission standard, resulting in low treatment efficiency.

[0003] Patent document CN206778176U discloses a treatment system for ammonia-containing waste gas, which uses dilute phosphoric acid instead of common dilute sulfuric acid as the absorption liquid to absorb ammonia in the waste gas, and uses magnesium hydroxide to further treat the solution of dilute phosphoric acid absorbing ammonia to form magnesium ammonium phosphate sludge precipitation and water, so as to achieve the absorption of ammonia in the waste gas. Although this technical solution is more energy-saving and environmentally friendly compared with the prior art, its essence is still to use an acid solution as the absorption liquid, and it still cannot avoid the low treatment efficiency caused by the reversible reaction of water absorbing ammonia and the reversible reaction of ammonia water and phosphoric acid. Therefore, it is still very necessary to design a waste gas purification device for efficiently absorbing ammonia. Summary of the Utility Model

[0004] Aiming at the problems existing in the above-mentioned prior art, the utility model provides a purification device and a purification system for efficiently absorbing organic amine and ammonia nitrogen waste gas, realizing the efficient treatment of organic amine and ammonia nitrogen waste gas and improving the absorption efficiency.

[0005] To achieve the above object, the technical solution of the utility model is as follows:

[0006] A purification device for efficiently absorbing organic amine and ammonia nitrogen waste gas includes an absorption tower, an absorption liquid tank, a dosing device and a solid-liquid separation device. An absorption liquid spraying device is arranged in the absorption tower; the dosing device includes a magnesium salt dosing device and a phosphoric acid or phosphate dosing device, and the magnesium salt dosing device and the phosphoric acid or phosphate dosing device are connected to the liquid inlet of the absorption liquid tank, and the liquid outlet of the absorption liquid tank is connected to the absorption liquid spraying device; the top and bottom of the absorption tower are respectively provided with a waste gas outlet and a discharge port, the bottom of the side wall of the absorption tower is provided with a waste gas inlet, and the discharge port is connected to the solid-liquid separation device; gas detection devices are installed at the waste gas inlet and the waste gas outlet, and a pH detection device is installed on the absorption liquid tank.

[0007] Furthermore, the absorption liquid tank is also provided with a circulating liquid inlet, and a power pump is also provided at the bottom of the absorption tower to circulate the liquid medicine at the bottom of the absorption tower into the absorption liquid tank and then recycle it through the absorption liquid spraying device.

[0008] Furthermore, a power pump and a pressure detection device are provided on the connecting pipeline between the absorption liquid tank and the absorption liquid spraying device.

[0009] Furthermore, the dosing device is an automatic dosing device. The magnesium salt dosing device and the phosphoric acid or phosphate dosing device both include a computer for controlling the dosing amount and time; the gas detection device and the pH detection device are both electrically connected to the computer.

[0010] Furthermore, the purification device further includes a waste liquid tank. A second spraying device is also provided in the absorption tower. The second spraying device is arranged below the absorption liquid spraying device. The liquid inlet and the liquid outlet of the waste liquid tank are respectively connected to the solid-liquid separation device and the second spraying device through pipelines to circulate the supernatant in the solid-liquid separation device into the absorption tower.

[0011] Furthermore, a power pump and a pressure detection device are also provided on the connecting pipeline between the waste liquid tank and the second spraying device.

[0012] Furthermore, a pH detection device is installed on the solid-liquid separation device for detecting the pH of the supernatant in the solid-liquid separation device.

[0013] Furthermore, the absorption tower is a cyclone spray tower.

[0014] The present utility model also provides a purification system for efficiently absorbing organic amine and ammonia-nitrogen waste gas, which includes at least one group of the purification devices and an exhaust chimney connected to the exhaust gas outlet of the purification device. Among them, the exhaust gas outlet of the last group of the purification devices is connected to the exhaust chimney, and the exhaust gas outlets of other groups of the purification devices are all connected to the exhaust gas inlet of the next group of the purification devices.

[0015] Furthermore, a check valve and a fan are installed on the connecting pipeline between the exhaust gas outlet and the exhaust chimney.

[0016] Compared with the prior art, the present utility model has the following beneficial effects: (1) The technical solution of the present utility model realizes the efficient absorption of ammonia in the waste gas and further reduces the cost by adjusting the magnesium salt medicine tank and the phosphoric acid or phosphate medicine tank to first enter the absorption liquid tank and then enter the absorption tower through the spraying device. (2) The treatment system provided by the present utility model has a simple design and low transformation cost on the basis of the existing purification system. Description of the Drawings

[0017] Figure 1It is a schematic structural diagram of the purification device described in Embodiment 1.

[0018] Figure 2 It is a schematic structural diagram of the purification device described in Embodiment 2.

[0019] Figure 3 It is a schematic flow diagram of the purification system of the present utility model

[0020] Wherein, 1. Absorption tower, 1-1. Exhaust gas outlet, 1-2. Exhaust gas inlet, 1-3. Discharge port, 1-4. Absorbent liquid spraying device, 1-5. Second spraying device, 2. Absorbent liquid tank, 3. Solid-liquid separation device, 4. Magnesium salt dosing device, 5. Phosphoric acid or phosphate dosing device, 6. Waste liquid tank, 7. Exhaust air duct. Detailed implementation manners

[0021] The following combines the drawings and embodiments to further describe in detail the specific implementation manners of the utility model. The following embodiments are used to illustrate the present utility model, but are not used to limit the scope of the present utility model.

[0022] Embodiment 1

[0023] As Figure 1 shown, this embodiment provides a purification device for efficiently absorbing organic amine and ammonia-nitrogen waste gas, including an absorption tower 1, an absorbent liquid tank 2, a solid-liquid separation device 3 and a dosing device; wherein, an exhaust gas outlet 1-1 is provided at the top of the absorption tower 1, an exhaust gas inlet 1-2 is provided on the bottom side wall, a discharge port 1-3 is provided at the bottom end, an absorbent liquid spraying device 1-4 is provided inside the absorption tower 1, and on-line gas detection devices for detecting the content of the waste gas to be absorbed are provided at both the exhaust gas outlet 1-1 and the exhaust gas inlet 1-2 (not shown in the figure);

[0024] The dosing device includes a magnesium salt dosing device 4 and a phosphoric acid or phosphate dosing device 5. The magnesium salt dosing device 4 and the phosphoric acid or phosphate dosing device 5 are both connected to the liquid inlet of the absorbent liquid tank 2 through pipelines. The liquid outlet pipeline of the absorbent liquid tank 2 is connected to the absorbent liquid spraying device 1-4. The mixed absorbent liquid in the absorbent liquid tank 2 is transported into the absorption tower 1 through the absorbent liquid spraying device 1-4, and then the waste gas is absorbed; the absorbent liquid tank 2 is also provided with a circulating liquid inlet, and a power pump is also provided at the bottom of the absorption tower 1 to circulate the liquid medicine at the bottom of the absorption tower 1 to the absorbent liquid tank 2 and recycle it through the absorbent liquid spraying device 1-4;

[0025] The discharge port 1-3 is connected to the solid-liquid separation device 3 to discharge the precipitate and part of the liquid mixture deposited at the bottom of the absorption tower 1 into the solid-liquid separation device 3 for subsequent treatment; a pH detection device is installed on the absorbent liquid tank 2.

[0026] In this embodiment, the absorption tower 1 is a cyclone spray tower.

[0027] In this embodiment, both the magnesium salt dosing device and the phosphoric acid or phosphate dosing device adopt existing conventional automatic dosing devices, both of which include a computer for controlling the dosage and time of dosing; the gas detection device and the pH detection device are both electrically connected to the computer, and the dosing is adjusted by monitoring the waste gas purification situation and the change of the pH value of the absorption liquid.

[0028] In this embodiment, valves are provided on each connecting pipeline.

[0029] Using the above purification device, the process is as follows: The waste gas enters the absorption tower 1 through the waste gas inlet 1-2. The automatic dosing device is controlled to transport magnesium salt and phosphate to the absorption liquid tank 2 respectively for mixing. The pH value of the mixed liquid in the absorption liquid tank 2 is monitored. The mixed absorption liquid is transported through the pipeline to the absorption liquid spraying device 1-4 for spraying. The ionic compound formed after the mixing of the magnesium salt and phosphate solution can react with the ammonium ions absorbed in the water to obtain magnesium ammonium phosphate precipitate; with the formation of the magnesium ammonium phosphate precipitate, the concentration of ammonium ions in the solution is reduced, so that the ammonia ionization equilibrium moves in the direction of producing ammonium ions, reducing the ammonia water concentration and the gas-phase equilibrium partial pressure at this concentration, thereby promoting the absorption efficiency of ammonia.

[0030] After the absorption liquid is circulated and sprayed for a period of time, the absorption effect of the absorption liquid decreases. The magnesium ammonium phosphate precipitate and part of the mixed liquid deposited at the bottom of the absorption tower 1 are collected into the solid-liquid separation device 3. The separated magnesium ammonium phosphate precipitate is collected for subsequent application, and the dosing device is controlled to supplement the absorption liquid. Moreover, during the operation of the purification device, the concentrations of the waste gas to be absorbed at the waste gas outlet 1-1 and the waste gas inlet 1-2 are continuously monitored, and the pH of the absorption liquid tank 2 is monitored at the same time. After running for a period of time, when the waste gas absorption efficiency drops below 98%, or when the pH of the absorption liquid tank 2 rises above 4.3, the automatic dosing device is controlled to supplement the liquid medicine.

[0031] Embodiment 2

[0032] As Figure 2As shown in the figure, this embodiment provides a purification device for efficiently absorbing organic amine and ammonia-nitrogen waste gas. Compared with Embodiment 1, the purification device described in this embodiment further includes a waste liquid tank 6. A second spraying device 1-5 is also provided inside the absorption tower 1. The second spraying device 1-5 is arranged below the absorption liquid spraying device 1-4. The liquid inlet and outlet of the waste liquid tank 6 are respectively connected to the upper middle part of the solid-liquid separation device 3 and the second spraying device 1-5 through pipelines. A power pump and a pressure detection device are provided on the connecting pipeline between the waste liquid tank 6 and the second spraying device 1-5. The waste liquid tank 6 is also provided with a liquid discharge port for directly discharging the waste liquid. This setting is used to circulate the supernatant liquid in the solid-liquid separation device 3 back into the absorption tower 1, thereby further improving the recovery and utilization of organic amine or ammonia-nitrogen waste gas.

[0033] Embodiment 3

[0034] As Figure 3 shown in the figure, this embodiment provides a purification system for efficiently absorbing organic amine and ammonia-nitrogen waste gas, including two sets of series-connected purification devices as described in Embodiment 1 and an exhaust chimney 7. Among them, the waste gas outlet 1-1 of the first set of purification devices is connected to the waste gas inlet 1-2 of the second set of purification devices. The waste gas outlet 1-1 of the second set of purification devices is connected to the exhaust chimney 7 through a pipeline. A check valve and a fan 8 are provided on the connecting pipeline between the waste gas outlet 1-1 and the exhaust chimney. A gas detection device is provided at the air outlet of the exhaust chimney 7 for detecting the content of ammonia-nitrogen or organic amine gas in the waste gas discharged after treatment.

[0035] The absorption effect of the ammonia-nitrogen waste gas absorption device provided in the above Embodiment 3 is detected, and at the same time, it is compared with the purification device of the prior art. The detection method is as follows: Inject the absorption liquid with the same concentration (1M) into the absorption liquid tank 2 at one time, and compare the absorption effects of ammonia gas by using the purification system of the present invention and the prior art under the same conditions. In this embodiment, the phosphate is dihydrogen phosphate, and the magnesium salt is magnesium chloride. The experimental conditions are: water content 200L, air volume 3000m 3 / h, normal temperature and pressure conditions.

[0036] It is known that at normal pressure and 25°C, the Henry's law constant of ammonia water is 4.952*10 4 Pa. Through calculation, the designed ammonia gas inlet concentration is 200mg / m 3 , according to Henry's law P B =k B *X B , it is calculated that the partial pressure of ammonia gas PB = 29.147Pa at normal temperature and pressure, and the concentration of ammonia in the liquid phase at gas-liquid equilibrium is 555g / L.

[0037] Using the purification system described in the present invention, the ammonia gas absorption results are shown in Table 1 below, where

[0038] Intermittent absorption amount = air volume * time interval * (inlet ammonia concentration - outlet ammonia concentration) / water volume;

[0039] Accumulative absorption amount = air volume * total time * (inlet ammonia concentration - outlet ammonia concentration) / water volume;

[0040] Absorption efficiency = (inlet ammonia concentration - outlet ammonia concentration) / water volume;

[0041] Molar ratio of absorption amount to dosage of medicine = [air volume * total time * (inlet ammonia concentration - outlet ammonia concentration) / 17 (g / mol)] / amount of substance of medicine added * 100%.

[0042] Table 1 Ammonia absorption results

[0043]

[0044]

[0045] It can be seen from the test results in Table 1 that for the purification devices of the phosphoric acid absorption experiment and the blank experiment, after operating for the same period of time, their absorption efficiencies decrease significantly, while for the purification device provided by the present utility model, it still has a significantly higher ammonia absorption efficiency.

[0046] In summary, by adopting a purification device and a purification system for efficiently absorbing organic amine and ammonia-nitrogen waste gas provided by the present utility model, the ammonia absorption efficiency can be significantly improved, thereby further reducing costs.

[0047] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present utility model. The scope of the present utility model is defined by the claims and their equivalents.

Claims

1. A purification device for efficiently absorbing organic amine and ammonia nitrogen waste gas, comprising an absorption tower, an absorption liquid tank, a chemical dosing device, and a solid-liquid separation device. An absorption liquid spraying device is provided inside the absorption tower; characterized in that, the chemical dosing device includes a magnesium salt dosing device, a phosphoric acid or phosphate dosing device. The magnesium salt dosing device and the phosphoric acid or phosphate dosing device are connected to the liquid inlet of the absorption liquid tank, and the liquid outlet of the absorption liquid tank is connected to the absorption liquid spraying device; an exhaust gas outlet and a discharge port are respectively provided at the top and bottom of the absorption tower, an exhaust gas inlet is provided at the bottom side wall of the absorption tower, and the discharge port is connected to the solid-liquid separation device; gas detection devices are installed at the exhaust gas inlet and the exhaust gas outlet, and a pH detection device is installed on the absorption liquid tank.

2. The purification device for efficiently absorbing organic amine and ammonia-nitrogen waste gas according to claim 1, wherein, The absorption liquid tank is further provided with a circulating liquid inlet, and a power pump is further provided at the bottom of the absorption tower to circulate the liquid medicine at the bottom of the absorption tower into the absorption liquid tank for recycling.

3. The purification device for efficiently absorbing organic amine and ammonia nitrogen waste gas according to claim 2, characterized in that, A power pump and a pressure detection device are provided on the connecting pipe between the absorption liquid tank and the absorption liquid spraying device.

4. The purification device for efficiently absorbing organic amine and ammonia nitrogen waste gas according to claim 1, characterized in that, The chemical dosing device is an automatic chemical dosing device. The magnesium salt dosing device and the phosphoric acid or phosphate dosing device both include a computer for controlling the dosage and time of chemical dosing; the gas detection device and the pH detection device are both electrically connected to the computer.

5. The purification device for efficiently absorbing organic amine and ammonia-nitrogen waste gas according to claim 1, wherein The purification device further includes a waste liquid tank. A second spraying device is further provided inside the absorption tower. The second spraying device is arranged below the absorption liquid spraying device. The liquid inlet and the liquid outlet of the waste liquid tank are respectively connected to the solid-liquid separation device and the second spraying device through pipelines to circulate the supernatant liquid in the solid-liquid separation device into the absorption tower.

6. The purification device for efficiently absorbing organic amine and ammonia-nitrogen waste gas according to claim 5, characterized in that, A power pump and a pressure detection device are provided on the connecting pipe between the waste liquid tank and the second spraying device.

7. The purification device for efficiently absorbing organic amine and ammonia-nitrogen waste gas according to claim 1, wherein A pH detection device is installed on the solid-liquid separation device.

8. The purification device for efficiently absorbing organic amine and ammonia nitrogen waste gas according to claim 1, characterized in that, The absorption tower is a cyclone spray tower.

9. A purification system for efficiently absorbing organic amine and ammonia-nitrogen waste gas, comprising at least one set of purification devices as described in any one of claims 1 to 8 and an exhaust chimney, wherein, The exhaust gas outlet of the last group of the purification devices is connected to an exhaust air duct, and the exhaust gas outlets of other groups of the purification devices are all connected to the exhaust gas inlet of the next group of the purification devices.

10. An efficient purification system for absorbing organic amine and ammonia-nitrogen waste gas according to claim 9, characterized in that, A check valve and a fan are installed on the connecting pipe between the exhaust gas outlet and the exhaust air duct.

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