TWI572559B - Purification and Recovery of Ammonia from Wastewater by Ammonia Wastewater - Google Patents

Description

Purification and concentration recovery of ammonia from ammonia-containing wastewater

The invention relates to the method for purifying and concentrating and recovering ammonia in the ammonia-containing wastewater, in particular, the ammonia concentration in the purification and concentration of ammonia is related to the technology of removing heavy metal ions, how to prevent the secondary pollution and resource utilization target, and the recycling can reach the city. Standardized products are sold to achieve harmless recycling technology.

A large amount of ammonia is used in the technology industry today. We use it extensively from LED, panel, solar cell (photovoltaic), semiconductor industry, and PCB industry. After use, it forms a large amount of ammonia-containing wastewater, and its ammonia-containing wastewater. There are heavy metal ions in the middle, which poses a risk of polluting the environment. Heavy metals are not removed and directly recovered. At present, this factor is often ignored in recycling operations, and it is unconsciously causing environmental damage. In the current treatment of ammonia recovery from ammonia-containing wastewater, the method of evaporating ammonia is mainly carried out by the stripping method and the ammonia distillation method (which is a comprehensive treatment of wastewater), and the excess heat is used to vaporize the ammonia in the wastewater. High-concentration wastewater often requires large equipment and more energy. The analysis is as follows:

1. Blowout treatment

The carrier (air or water vapor) is introduced into the wastewater to apply the gas-liquid interface, and the liquid phase is contacted with the liquid phase via the gas phase to dissolve the free ammonia in the water, and the gas-liquid medium is transferred to the gas phase. The stripping method generally has two main equipments, a blow-off tank (removal) and a stripping tower (adsorption). In operation, a large amount of gas is required to be driven into the wastewater, and the water will move the ammonia with the gas. Out, the back-end gas adsorption device must have sufficient adsorption capacity, its adsorption is a large amount of air and ammonia mixed gas (large equipment), or high-temperature water vapor and ammonia (adsorption requires a large condensation system), relatively high cost, generally only used for high The recovery of ammonia from the concentration of ammonia-containing wastewater has limited economic benefits.

2. Steaming ammonia treatment

It is mainly to use the extra heat to directly heat the wastewater, to evaporate ammonia from the wastewater, and to evaporate requires a large amount of heat. The use of heat to completely evaporate the ammonia in the wastewater requires higher temperature. The higher the temperature, the higher the water vapor and the higher the temperature, the higher the energy consumption for the latter stage. The same is limited to the high-concentration ammonia-containing wastewater treatment application. It needs a lot of money, high investment and low efficiency.

It can be seen from the above that the treatment of ammonia-containing wastewater requires a large amount of energy and high equipment cost, requires a large treatment site, requires additional energy or a carrier, forms excessive loss, and how to purify and concentrate ammonia in the wastewater efficiently and at low cost to achieve marketization. The standard is a major environmental problem.

The main purpose of the invention is to prevent heavy metal ions in the ammonia-containing wastewater from polluting the environment, especially in the recycling process, to make the ammonia recovery resource-recycling and harmless, prevent environmental pollution, and improve the reusable range.

Another main object of the present invention is to vaporize, purify and concentrate ammonia in wastewater (to leave macromolecular impurities in the liquid phase), remove impurities, improve the quality and concentration of recovered ammonia, and increase the value of recycled products to make them conform to commercial products. Specifications, improve recycling efficiency, let the factory have a willingness to invest.

Another main object of the present invention is to distill ammonia from waste water and apply a high efficiency section. It can reduce the loss of ammonia recovery energy, and especially expand the surface area mode to maximize the surface area of ammonia-containing wastewater. In particular, the pressurized spray evaporation mode is applied to atomize ammonia-containing wastewater, allowing ammonia to be quickly removed from the liquid phase and further penetrated. The gas-liquid separation tank separates the gas and liquid phases, so that most of the ammonia can be removed from the gas phase for purification and concentration purposes, and then the gasification part is condensed by circulating water to capture (using the venturi principle to adsorb) ammonia. Dissolved in ice water, accumulated absorption over time, up to the concentration specifications of commercial products, to achieve commercialization goals.

Another main object of the present invention is to use energy transfer technology to reduce the cost of recovery ammonia treatment, especially to build a heat pump system, and to apply the advantages of heat pump cold heat exchange (heat output temperature 40 ° C ~ 80 ° C, cold output temperature 0 ° C ~ 20 ° C) The heat output energy is supplied to the ammonia in the waste water to evaporate heat energy to meet the heating demand before evaporation. The other cold output provides a cooling effect of circulating ice water, and the heat energy generated by dissolving ammonia in water is taken away, so that ammonia is quickly dissolved in water to achieve effective capture.

In order to achieve the above purposes, a new treatment and recycling resource scheme has been specially established. The ammonia is evaporated from the wastewater by ammonia evaporation conditions, and the ammonia is separated from the water to achieve the purpose of purification. Generally, the macromolecular impurities will remain in the liquid phase and will not follow The ammonia is distilled off, thereby purifying and concentrating ammonia. Especially in the design of the system from the evaporation conditions, in addition to the basic heat energy, there is air pressure and surface area. The lower the pressure, the easier it is to evaporate. The other is the surface area. The surface area is easy to achieve rapid evaporation. Therefore, pressurized atomization is built into the system to increase the surface area. The venturi water is used to establish the negative pressure absorption effect of the venturi, so that the ammonia in the wastewater can be quickly evaporated. When it comes out, it absorbs ammonia by purifying circulating ice water, and the absorption concentration will gradually increase, reaching the specifications of commercial products, and achieving commercialization.

The implementation procedure is as follows (as shown in Figure 1).

Procedure (1), filtering and slag removal

Dissolve the waste ammonia water to remove suspended solids and solids from the water, and mix the water The mass is intercepted and the solid impurities can be removed by backwashing.

Procedure (2), heavy metal ion adsorption

The use of ion exchange resin adsorption to remove heavy metal ions in the wastewater to prevent ammonia pollution has secondary pollution risks. The adsorbed metal ions can use the reducing agent to remove the metal ion compounds out of the system, so that the ammonia-containing wastewater can be further removed and purified.

Procedure (3), pressurization and warming

The ammonia-containing wastewater is transported through the pressurized pump power, and during the process, the heat required to supply the ammonia through the heat pump and the heat exchanger is used to warm the ammonia, and the temperature is set at 40 ° C to 80 ° C to increase the removal of ammonia. The effect is to improve the processing power of the device.

Procedure (four), spray evaporation

The high-pressure permeation nozzle is used to enlarge the surface area of the ammonia-containing wastewater (formation of mist), allowing ammonia to evaporate quickly and remove the liquid phase, and most of the ammonia and part of the water evaporate to form an ammonia purification and concentration effect, and the macromolecule is not easily vaporized. The molecule will remain in the liquid phase, and further gasification will allow the ammonia to be purified, further increasing the ratio of ammonia to water concentration, and forming an ammonia concentration effect.

Procedure (5), gas-liquid separation

The deaminated wastewater, which has a large molecular weight impurity and water condensed into a liquid phase, is removed from the gas-liquid separation tank through a buffer gas-liquid separation tank, and ammonia and a part of water vaporization are taken out from above.

Procedure (6), circulating ice water absorption

The condensing temperature is set at 0 ° C ~ 20 ° C, absorbing ammonia to form regenerated ammonia water, gas phase The ammonia gas and water vapor can be circulated and adsorbed by circulating water, and the venturi principle is used to form a vacuum adsorption effect, which can quickly absorb the gasification to form regenerated ammonia water, and the regenerated ammonia water will increase the concentration of regenerated ammonia water due to an increase in cycle time, and further It can reach the concentration standard of commercial products and can be directly sold or further concentrated to form liquid ammonia to achieve the purpose of resource utilization.

Procedure (7), concentration detection

The concentration of ammonia water in the absorption tank is monitored. When the ammonia concentration check meets the product specifications, it can be directly reused. In order to ensure the regeneration quality of the resource recovery, the regenerated ammonia water is introduced and the pure water is added to absorb the ammonia.

Procedure (8), shipping marketing

After the quality inspection is passed, the regenerated ammonia water can be taken out of the system and stored in the temporary storage tank for shipment.

The liquid phase wastewater in the gas-liquid separation tank is de-ammonia wastewater, and most of the ammonia has been removed, which can be discharged after simple treatment, and the de-ammonia wastewater can be directly returned to the production process for reuse, such as waste ammonia treatment and washing. Water, circulating water or clean water, improve water reuse, and achieve energy saving and emission reduction targets. The evaporation of the ammonia water in the front section is set to 40 °C ~ 80 °C and the absorption of ammonia water in the downstream ice water circulating water is 0 °C ~ 20 °C, then a group of heat pumps can achieve a energy efficient conversion mode, reducing energy loss and achieving clean treatment. aims.

1‧‧‧Ammonia wastewater

2‧‧‧Deamination wastewater

3‧‧‧ pure water

4‧‧‧Ammonia cycle ice water

5‧‧‧High concentration of purified ammonia

6‧‧‧In addition to impurities containing ammonia wastewater

10‧‧‧Filter

11‧‧‧Filter desorption device

12‧‧‧ Residue collection tank

13‧‧‧ solid residue

20‧‧‧Ion exchange resin adsorption tank

21‧‧‧Desorbed backwashing device

22‧‧‧Metal compound collection tank

23‧‧‧Metal compounds

24‧‧‧Reducing agent

25‧‧‧In addition to impurity ammonia-containing wastewater collection tank

30‧‧‧heating heat exchanger

40‧‧‧ gas-liquid separation tank

41‧‧‧ spray evaporator

42‧‧‧ gas-liquid separation tank gas outlet

T1‧‧‧heating temperature control table

T2‧‧‧Cooling temperature control table

P‧‧‧ pressure gauge

P1‧‧‧Ammonia wastewater input pump

P2‧‧‧Pressure pump

P3‧‧‧Deamination wastewater output pump

P4‧‧‧Circulating ice water pump

P5‧‧‧High concentration purified ammonia water output pump

Q‧‧‧ concentration meter

L1‧‧‧Evaporator Level Gauge

L2‧‧‧Circulating ice water level gauge

L3‧‧‧High concentration purified ammonia water level gauge

L4‧‧‧Deamination wastewater level gauge

43‧‧‧liquid-liquid separation tank liquid outlet

44‧‧‧Ammonia

45‧‧‧Water and gas

50‧‧‧Condensation circulation absorption tank

51‧‧‧ venturi tube

52‧‧‧Pure water supplement valve

53‧‧‧High concentration purified ammonia water collection tank

54‧‧‧High concentration purified ammonia water output device

55‧‧‧Draining device

60‧‧‧Cooling heat exchanger

70‧‧‧Heat pump system

80‧‧‧Deamination wastewater collection tank

81‧‧‧Deamination wastewater collection device

Figure 1. Flow chart of purification, concentration, recovery and reuse in ammonia-containing wastewater.

Figure 2. Diagram of waste ammonia recovery and purification system.

As shown in FIG. 2, the ammonia-containing wastewater 1 in the plant is introduced into the filter 10 through the ammonia-containing wastewater input pump P1, and the solid residue 13 is left on the filter 10. The solid residue 13 on the filter 10 can be removed by the filter. Attached to the device 11, the solid residue 13 is desorbed and moved into the residue collection tank 12. The waste ammonia water passing through the filter 10 is further flowed into the ion exchange resin adsorption tank 20, and the metal ions in the waste ammonia water are adsorbed to form an impurity-containing ammonia wastewater 6 and then flowed into the impurity-containing ammonia wastewater collection tank 25 to achieve primary purification. The metal ion compound can permeate the adsorbed metal ions through the reducing agent 24 and the desorption backwashing device 21 to form the metal compound 23, and is introduced into the metal compound collecting tank 22.

In addition to the impurity ammonia-containing wastewater 6 is pressurized by the pressure pump P2 and introduced into the heating heat exchanger 30 to absorb the heat energy required for evaporating ammonia, and the heat energy of the heat pump can be used to output a heat of about 40 ° C to 80 ° C, and then sprayed. The evaporator 41 atomizes the impurity-containing ammonia wastewater 6 to increase the evaporation surface area, so that the ammonia in the impurity-containing ammonia wastewater 6 can be quickly evaporated and vaporized, and the gas-liquid separation tank 40 is passed through the gas-liquid separation tank 40 to allow most of the ammonia gas 44 and the water gas 45. The gas is taken out from the vapor-liquid outlet 42 of the gas-liquid separation tank, and the liquid phase is taken out from the liquid-liquid outlet 43 of the gas-liquid separation tank to form the deamination wastewater 2.

The pure water 3 is introduced into the condensing circulation absorption tank 50 through the pure water replenishing valve 52, and is extracted by the circulating ice water pump P4, and formed into ice water of 0 ° C to 20 ° C through the cooling heat exchanger 60 to adsorb and condense ammonia to form ammonia. Circulating ice water 4. By forming the venturi 51 through the ammonia circulation circulating ice water 4 cycle, the vaporized gas in the gas-liquid separation tank 40 can be quickly drawn into the condensation circulation absorption tank 50 to condense and suck. Attached. The ammonia content in the ammonia-suppressing ice water 4 will gradually increase. The ammonia concentration can be measured by the concentration meter Q. When the concentration reaches the commercially available standard ammonia water, it can be extracted from the high-concentration purified ammonia water output pump P5 and introduced into the high-concentration purified ammonia water collection tank 53. Save and prepare for shipment.

The deamination wastewater 2 in the gas-liquid separation tank 40 can be taken out from the deamination wastewater output pump P3 to the deamination wastewater collection tank 80, and further recycled or discharged through simple treatment to achieve effective recycling and harmless treatment mode. .

For heating and cooling requirements, the energy exchange operation can be performed by using the hot pump 70 hot end output 40 ° C ~ 80 ° C and the cold end output 0 ° C ~ 20 ° C.

Claims (6)

A method for purifying and concentrating and recovering ammonia from ammonia-containing wastewater, the procedure of which is as follows: (1) filtering and slag removal: waste ammonia water for slag removal, removing suspended solids and solid matter in water; (2) adsorption of heavy metal ions: using ions Exchanging resin adsorption to remove heavy metal ions in wastewater; (3) Pressurization and temperature rise: Waste ammonia water is transported through the power of the pressurized pump, and during the process, the energy required for steaming ammonia is supplied through the heat pump and the heat exchanger to warm the ammonia. The temperature is set at 40 ° C ~ 80 ° C; (d), spray evaporation: the use of high pressure through the nozzle to make the waste ammonia water into a mist and surface area expansion, allowing ammonia to quickly evaporate and remove the liquid phase, the formation of ammonia purification and concentration effect; 5), gas-liquid separation: through gas-liquid separation tank, to achieve gas-liquid separation; (6), circulating ice water absorption: program (5) gas phase ammonia and water vapor temperature set at 0 ° C ~ 20 ° C circulating ice The water cycle absorbs and forms regenerated ammonia water; (7) Concentration detection: The concentration of ammonia water in the absorption tank is monitored, and the ammonia water concentration can be directly reused when it meets the product specifications. As claimed in claim 1, the method for purifying, concentrating, and recovering ammonia from the ammonia-containing wastewater is as follows: (1) The method of filtering and removing the slag is to remove the solid residue by backwashing. If the request item 1 is purified from the ammonia-containing wastewater, the method of reusing and recovering ammonia is used. The procedure (2) is to use metal ion exchange resin to adsorb heavy metal ions. When it is saturated, it can be removed by washing with a reducing agent, and the metal ion exchange resin is activated and reused. If the request item 1 is purified from the ammonia-containing wastewater, and the ammonia is reused, the procedure (4) spray evaporation system expands the surface area of the ammonia-containing wastewater, increases the kinetic energy of the water through a high-pressure pump, and atomizes the ammonia-containing wastewater through the atomizing nozzle. The formation of atomized small molecules allows the ammonia to be quickly distilled off to achieve the purpose of deamination. If the request item 1 is purified from the ammonia-containing wastewater and the ammonia is reused, the procedure (6) circulating ice water is formed into a venturi negative pressure through the cyclic motion, and the vapor of the program (5) is quickly absorbed. If the request item 1 is purified from the ammonia-containing wastewater, the ammonia is reused, and the program (3) heat pump provides heating and cooling applications. The heat pump heat output temperature is 40 ° C ~ 80 ° C, and the cold output temperature is 0 ° C ~ 20 ° C. The heat output energy is supplied to the ammonia in the waste water to evaporate the heat energy to meet the heating demand before evaporation; and the other cold output end provides the circulating ice water cooling effect, the heat energy generated by dissolving the ammonia in the water is taken away, and the ammonia is quickly dissolved in the water. Achieve effective capture.