Method for treating refractory wastewater by virtue of supercritical water oxidation technology

A supercritical water oxidation and technical treatment technology, applied in the field of refractory wastewater treatment, can solve the problems of ammonia nitrogen, COD difficult to meet the discharge standard, complex treatment process, large area, etc., to achieve no secondary pollution, process flow Short, high heat transfer efficiency

Inactive Publication Date: 2014-02-26
SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method is not only complicated in the treatment process, requires a lot of equipment investment, and occupies a large area, but also the ammonia nitrogen and COD in the effluent are difficult to meet the emission standards.

Method used

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  • Method for treating refractory wastewater by virtue of supercritical water oxidation technology

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Embodiment 1

[0029] The high-concentration coal gasification wastewater containing high concentrations of ammonia nitrogen, phenols, COD and inorganic salts was treated with supercritical water oxidation. The raw water quality of the wastewater used is shown in Table 1. The wastewater in the wastewater storage tank 1 is pressurized to 24MPa by the high-pressure pump 3 and input to the heat exchanger 5 for preheating. After the wastewater is preheated to 360°C, it flows into the salt separator 7 with a temperature of 650°C for desalination; at the same time, the oxidant is sent from the storage tank 2 The high-pressure pump 4 pressurizes to 24MPa and enters the heat exchanger 6 for preheating, and the oxidant heated to 640°C by the heater 9 and the desalted waste water respectively flow into both ends of the supercritical water oxidation reactor 8 for supercritical water oxidation reaction. The amount of oxidant used is 4 times of the theoretical oxygen demand, the residence time of the was...

Embodiment 2

[0031] The high-concentration coking wastewater containing high concentrations of ammonia nitrogen, phenols, COD and inorganic salts was treated with supercritical water oxidation. The raw water quality of the wastewater used is shown in Table 1. The wastewater in the wastewater storage tank 1 is pressurized to 25MPa by the high-pressure pump 3 and input to the heat exchanger 5 for preheating. After the wastewater is preheated to 355°C, it flows into the salt separator 7 with a temperature of 650°C for desalination; at the same time, oxygen is sent from the storage tank 2 The high-pressure pump 4 pressurizes to 25MPa and enters the heat exchanger 6 for preheating. The oxidant heated to 650°C by the heater 9 and the desalted waste water respectively flow into both ends of the supercritical water oxidation reactor 8 for supercritical water oxidation. reaction. The amount of oxidant used is 5 times of the theoretical oxygen demand, the residence time of the waste water in the sup...

Embodiment 3

[0033]The high-concentration cotton textile printing and dyeing wastewater containing ammonia nitrogen, COD and inorganic salts was treated with supercritical water oxidation. The raw water quality of the wastewater used is shown in Table 1. The waste water in the waste water storage tank 1 is pressurized to 25 MPa by the high pressure pump 3 and input into the heat exchanger 5 for preheating. At the same time, the hydrogen peroxide solution is pressurized from the storage tank 2 to 25MPa by the high-pressure pump 4 and input into the heat exchanger 6 for preheating, and the oxidant and the desalted waste water heated to 500°C by the heater 9 are sent to the supercritical water oxidation reactor respectively. 8 flow in at both ends to carry out the supercritical water oxidation reaction. The amount of oxidant used is 2.5 times of the theoretical oxygen demand, the residence time of the waste water in the supercritical water oxidation reactor 8 is 20 seconds, and the system pre...

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Abstract

The invention provides a method for treating refractory wastewater by virtue of a supercritical water oxidation technology. The method comprises the following steps of: feeding the preheated wastewater into a salt separator for supercritical desalination, heating an oxidant which is preheated previously through a heat exchanger to a desired temperature, feeding the heated oxidant and the desalinated wastewater into a supercritical water oxidation reactor from the two ends of the reactor, respectively, controlling the system pressure by a back pressure valve, and carrying out a supercritical water oxidation reaction to degrade pollutants in the wastewater into non-toxic matters such as CO2, N2 and H2O; feeding the clean high-temperature and high-pressure fluid obtained after the reaction into the heat exchanger to exchange heat with the wastewater and the oxidant, respectively, and then cooling and separating, returning the excessive oxidant to the supercritical water oxidation reactor and causing the liquid into a normal-pressure gas-liquid separator, discharging the gases such as CO2 and N2 through the top of the normal-pressure gas-liquid separator, and discharging the treated clean water from the bottom of the normal-pressure gas-liquid separator. The method for treating the refractory wastewater by virtue of the supercritical water oxidation technology has the advantages of being high in wastewater treatment efficiency without secondary pollution, and suitable for treating the refractory wastewater different in concentration.

Description

technical field [0001] The invention relates to a treatment method for refractory wastewater, more specifically a method for supercritical water oxidation treatment of refractory wastewater. Background technique [0002] Refractory wastewater is a kind of industrial wastewater that is difficult to treat. It is mainly wastewater produced in the production process of dyes, pesticides, medical treatment, coking, etc. It has large discharge volume, high pollutant concentration, high toxicity, and its composition is complex and changeable. High oxygen content, difficult to biodegrade. Usually, wastewater contains a large amount of ammonia nitrogen, phenolic substances, monocyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons, and heterocyclic compounds containing nitrogen, sulfur, and oxygen, and the content of inorganic salts in wastewater is also high. Ammonia and phenols are highly toxic compounds, which will cause serious water pollution when entering the water ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/72
Inventor 毕继诚杜新曲旋孙东凯阎晓强张荣
Owner SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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