Nitric acid production wastewater recovery treatment system

Abstract

The utility model discloses a nitric acid production wastewater recovery treatment system, which belongs to the field of wastewater treatment, and comprises a plurality of storage tanks, an acidity regulator, a vacuum rectifying tower, a fluidized bed reactor and a dehydrator which are sequentially arranged, the vacuum rectifying tower is used for heating and distilling nitric acid wastewater, slaked lime is added into the fluidized bed reactor, the vacuum rectifying tower is connected with the condenser, and the condenser is used for condensing and liquefying nitric acid steam; the vacuum rectifying tower preliminarily treats nitric acid-containing wastewater, efficiently recycles nitric acid and improves the resource utilization rate; slaked lime is added into the fluidized bed reactor to generate calcium nitrate, so that harmful components in the wastewater can be converted into valuable chemical raw materials, waste is turned into wealth, harmless treatment of the wastewater is realized, and subsequent treatment cost and environmental risk are reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of wastewater treatment, and in particular relates to a nitric acid production wastewater recovery and treatment system. Background Art

[0002] A large amount of nitric acid-containing wastewater generated during the nitric acid production process is extremely harmful once it is directly discharged. The high concentration of nitric acid in the wastewater causes the pH value of the water body to drop sharply, aggravating the deterioration of water quality. Nitrogen oxides cause eutrophication, and algae grow wildly, depleting dissolved oxygen, resulting in the death of a large number of aquatic organisms; acidic wastewater flows into the soil, destroying the nutrient balance of the soil, causing hardening and salinization, and causing heavy metals to accumulate continuously, affecting plant growth; this not only seriously damages the biodiversity and stability of aquatic and terrestrial ecosystems, disrupts the food chain, but also threatens human health through direct contact and food chain transmission, causing skin damage and heavy metal poisoning, especially endangering the safety of drinking water, and bringing heavy disasters to the ecological environment and human survival.

[0003] In traditional nitric acid wastewater treatment, alkali is directly added for neutralization reaction, and nitrate waste residue is finally generated. Under this treatment method, the nitric acid recovery rate is extremely low, and the recyclable nitric acid resources are wasted. At the same time, the subsequent treatment of these nitric acid-containing waste residues requires high costs, which further increases the economic burden of the entire production process. At the same time, the discharge of nitric acid wastewater pollutes the environment. Utility Model Content

[0004] The utility model aims to provide a nitric acid production wastewater recovery and treatment system to solve the problems of low nitric acid recovery rate in traditional nitric acid wastewater treatment, high treatment cost of generated nitrate waste residue and easy environmental pollution.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a nitric acid production wastewater recovery and treatment system, comprising a storage tank, an acidity regulator, a vacuum distillation tower, a fluidized bed reactor and a dehydrator arranged in sequence;

[0006] The storage tanks are provided in plurality, and the plurality of storage tanks respectively store nitric acid wastewater with different concentrations;

[0007] The vacuum distillation tower heats and distills the nitric acid wastewater;

[0008] Slaked lime is added into the fluidized bed reactor.

[0009] Furthermore, the vacuum distillation tower is connected to a condenser, and the condenser condenses and liquefies the nitric acid vapor.

[0010] Furthermore, the wastewater produced by the fluidized bed reactor and the dehydrator enters a sewage treatment system.

[0011] Furthermore, a pipeline pump is installed between the storage tank and the acidity regulator.

[0012] Furthermore, a swirl mixing tube is provided in the acidity regulator.

[0013] Furthermore, a spiral heating tube is provided in the vacuum distillation tower, and a high-temperature fluid is injected into the spiral heating tube.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] The nitric acid production wastewater recovery and treatment system uses a vacuum distillation tower to initially treat nitric acid-containing wastewater, efficiently recover nitric acid, and improve resource utilization. The addition of slaked lime into the fluidized bed reactor generates calcium nitrate, which not only converts harmful components in the wastewater into valuable chemical raw materials, turning waste into treasure, but also achieves harmless treatment of the wastewater, reducing subsequent treatment costs and environmental risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the nitric acid production wastewater recovery and treatment system;

[0017] Figure 2 for Figure 1 Enlarged schematic diagram at point A in the middle.

[0018] In the figure: 10, storage tank; 110, pipeline pump; 20, acidity regulator; 210, swirl mixing tube; 220, spiral blade; 30, vacuum distillation tower; 301, spiral heating tube; 302, wastewater path extension baffle; 303, gas flow channel; 310, condenser; 40, fluidized bed reactor; 50, dehydrator. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the embodiments.

[0020] The following examples are used to illustrate the present invention, but cannot be used to limit the scope of protection of the present invention. The conditions in the examples can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention are all within the scope of protection claimed by the present invention.

[0021] See also Figure 1 and Figure 2 The utility model provides a nitric acid production wastewater recovery and treatment system, comprising a storage tank 10, an acidity regulator 20, a vacuum distillation tower 30, a fluidized bed reactor 40 and a dehydrator 50 which are arranged in sequence.

[0022] The storage tank 10 is used to temporarily store wastewater. A plurality of storage tanks 10 may be provided, and the plurality of storage tanks 10 respectively store nitric acid wastewater of different concentrations.

[0023] A pipeline pump 110 is installed between the storage tank 10 and the acidity regulator 20 to transport the waste acid in the storage tank 10 to the acidity regulator 20. A cyclone mixing tube 210 is provided in the acidity regulator 20. High-concentration nitric acid wastewater and low-concentration nitric acid wastewater enter the cyclone mixing tube 210 through different pipelines. In the cyclone mixing tube 210, the high-speed flowing wastewater generates a strong vortex under the action of the spiral blades 220, so that the wastewaters of different concentrations are fully mixed, so that the concentrations of the nitric acid wastewaters in the two storage tanks 10 are evenly mixed, so that the concentration of the nitric acid wastewater entering the subsequent treatment link can be kept relatively stable, and the controllability and stability of the treatment process can be improved.

[0024] The vacuum distillation tower 30 is provided with a spiral heating tube 301. After the wastewater enters the vacuum distillation tower 30, it will flow in an "S" shape along the wastewater path extension baffle 302 to the bottom of the inner cavity of the vacuum distillation tower 30. The nitric acid wastewater is heated by introducing a heating medium (steam) into the spiral heating tube 301. The gas vaporized by the heated nitric acid wastewater will flow upward through the gas flow channel 303 on the wastewater path extension baffle 302 and enter the condenser 310 to liquefy into nitric acid. Nitric acid has high volatility and a relatively low boiling point. Steam is introduced through the spiral heating tube 301 to heat the nitric acid wastewater. When the boiling point of nitric acid is reached, nitric acid will vaporize into a gaseous state, and nitric acid enters the condenser 310 in a gaseous form. The condenser 310 cools the gaseous nitric acid through a cooling medium (such as cold water), so that the nitric acid vapor is cooled and liquefied, and becomes liquid nitric acid again, realizing the recycling of resources, and also reducing the pollution of nitric acid to the environment.

[0025] Slaked lime is added into the fluidized bed reactor 40; after the wastewater is distilled, unreacted nitric acid still exists in the wastewater. Nitric acid is strongly acidic, and slaked lime is an alkaline substance. The addition of slaked lime can react with nitric acid to reduce the acidity of the wastewater, so that the pH value of the wastewater reaches a range more suitable for subsequent treatment or discharge. By adding slaked lime to react with nitric acid, the resource recovery and utilization of nitric acid is realized, and resource waste is reduced.

[0026] The chemical reaction equation for the neutralization reaction of slaked lime (Ca(OH)2) and nitric acid (HNO3) is: Ca(OH)2+2HNO3=Ca(NO3)2+2H2O;

[0027] The dehydrator 50 is used to separate the waste liquid containing crystals and calcium nitrate. The wastewater produced by the fluidized bed reactor 40 and the dehydrator 50 enters the sewage treatment system for subsequent treatment; the sewage treatment system uses the existing grid, primary sedimentation tank, biological treatment structure (such as aeration tank and biological contact oxidation tank) and secondary sedimentation tank treatment process in sequence to complete the sewage treatment.

[0028] The working principle and use process of the utility model are as follows: nitric acid wastewater with different concentrations is injected into different storage tanks 10, and the waste acid in the storage tank 10 is transported to the acidity regulator 20. The high-concentration nitric acid wastewater and the low-concentration nitric acid wastewater enter the cyclone mixing tube 210 through different pipelines respectively. In the cyclone mixing tube 210, the high-speed flowing wastewater generates a strong vortex under the action of the spiral blades 220, so that the wastewater with different concentrations is fully mixed, and the nitric acid wastewater in the two storage tanks 10 is evenly mixed. The nitric acid wastewater is heated and distilled by introducing a heating medium (steam). The gas generated by the heating of the wastewater enters the condenser 310 and is liquefied into nitric acid. After the wastewater is distilled, unreacted nitric acid still exists in the wastewater. Nitric acid is strongly acidic. Slaked lime is an alkaline substance. Adding slaked lime can react with nitric acid to reduce the acidity of the wastewater, so that the pH value of the wastewater reaches a range more suitable for subsequent treatment or discharge. By adding slaked lime to react with nitric acid, the resource recovery and utilization of nitric acid is realized, and the waste of resources is reduced.

[0029] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A nitric acid production wastewater recovery and treatment system, characterized in that: It comprises a storage tank (10), an acidity regulator (20), a vacuum distillation tower (30), a fluidized bed reactor (40) and a dehydrator (50) which are arranged in sequence; A plurality of storage tanks (10) are provided, and the plurality of storage tanks (10) respectively store nitric acid wastewater with different concentrations; The vacuum distillation tower (30) heats and distills the nitric acid wastewater; Slaked lime is added into the fluidized bed reactor (40).

2. A nitric acid production wastewater recovery and treatment system according to claim 1, characterized in that: The vacuum distillation tower (30) is connected to a condenser (310), and the condenser (310) condenses and liquefies the nitric acid vapor.

3. A nitric acid production wastewater recovery and treatment system according to claim 1, characterized in that: The wastewater produced by the fluidized bed reactor (40) and the dehydrator (50) enters the sewage treatment system.

4. A nitric acid production wastewater recovery and treatment system according to claim 1, characterized in that: A pipeline pump (110) is installed between the storage tank (10) and the acidity regulator (20).

5. A nitric acid production wastewater recovery and treatment system according to claim 1, characterized in that: A cyclone mixing tube (210) is provided in the acidity regulator (20).

6. A nitric acid production wastewater recovery and treatment system according to claim 1, characterized in that: The vacuum distillation tower (30) is provided with a spiral heating tube (301), and a high-temperature fluid is injected into the spiral heating tube (301).

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