CN217895360U

CN217895360U - A device that is used for high salt of PO SM, high COD waste water treatment

Info

Publication number: CN217895360U
Application number: CN202221706281.9U
Authority: CN
Inventors: 邵新海; 李青山; 崔浩; 李耀
Original assignee: Tianjin Bohua Chemical Development Co ltd
Current assignee: Tianjin Bohua Chemical Development Co ltd
Priority date: 2022-07-04
Filing date: 2022-07-04
Publication date: 2022-11-25
Anticipated expiration: 2032-07-04

Abstract

A device for PO/SM high-salt and high-COD wastewater treatment belongs to the technical field of wastewater treatment. The system consists of a waste water storage tank, a low-pressure water feeding pump, a high-pressure feeding pump, a feeding and discharging heat exchanger, a reactor, a process cooler, a pressure reducing valve, a separator and a homogenizing tank; mixing the high-pressure pumped liquid with compressed air from an air compressor to form a two-phase flow mixture; the preheated two-phase flow mixture enters the bottom of the reactor and is subjected to oxidation reaction together with pure oxygen from the outside of the device; and conveying the oxidized sewage and non-condensable gas mixture subjected to heat exchange to a process cooler, and separating a gas phase and a liquid phase from the cooled oxidized sewage and non-condensable gas mixture in a separator, thereby finishing the treatment of the PO/SM high-salt and high-COD wastewater. The utility model discloses can effectually be high salt, high COD sewage oxidative decomposition for low COD, improve the biodegradability of this kind of sewage, reduce the processing degree of difficulty of sewage, reduce the pollution to the environment.

Description

A device that is used for high salt of PO SM, high COD waste water treatment

Technical Field

The utility model belongs to the technical field of waste water treatment, concretely relates to a device that is used for PO/SM high salt, high COD waste water treatment.

Background

The PO/SM (propylene oxide co-production styrene) technology is widely used in China, and the environmental protection problem comes along with the PO/SM technology, because the sewage has the characteristics of high salt, high COD and the like, the treatment difficulty is very high, the treatment method is single, and at present, similar domestic waste water is mostly treated by adopting an incineration method. The burning method has very high energy consumption, and simultaneously, the generated waste gas contains more nitrate, so that the waste water pollution is converted into waste gas pollution. Therefore, the treatment technologies with low energy consumption and low pollution are gradually pilot-tested and put into production, and the technologies which can be applied to industrialization at present include a supercritical technology and a wet oxidation technology. The utility model provides a device for treating wastewater with high salt content and high COD in PO/SM, and adopts wet oxidation technology to treat wastewater with high salt content and high COD.

Disclosure of Invention

The device uses up-to-date sewage treatment technique to replace traditional incineration method to handle high salt, high COD sewage, reaches and reduces energy resource consumption, reduces the purpose to environmental pollution, can effectually be with high salt, high COD sewage oxidative decomposition for low COD, has improved the biodegradability of this kind of sewage, reduces the processing degree of difficulty of sewage, reduces the pollution to the environment.

A device for PO SM high salt, high COD waste water treatment constitute by waste water storage tank 1, low pressure feed pump 2, high-pressure charge pump 3, business turn over material heat exchanger 4, reactor 5, technology cooler 6, relief pressure valve 7, separator 8, homogeneity pond 9, connect through pipeline between each part.

The device adopts a wet oxidation method to treat sewage, and the main process flow is as follows:

the low-pressure feed pump 2 sends the high-salt and high-COD wastewater stored in the wastewater storage tank 1 to the high-pressure feed pump 3, and the high-pressure pumped liquid is mixed with compressed air from an air compressor to form a two-phase flow mixture; the two-phase flow mixture and the high-temperature discharge of the reactor 5 (when the device starts to be started, the high-temperature discharge of the reactor 5 is high-temperature water vapor, and the outlet temperature of the reactor 5 is maintained at 270 to 290 ℃) in the charging and discharging heat exchanger 4 to carry out indirect heat exchange, so that the two-phase mixture is preheated; the preheated two-phase flow mixture with the temperature of 170 to 210 ℃ enters the bottom of the reactor 5 and is subjected to oxidation reaction together with pure oxygen from an oxygen compressor;

the high-salt and high-COD wastewater in the reactor 5 is mixed with oxygen under the action of compressed air which rises and passes through the wastewater, the oxygen is dissolved into the wastewater to carry out oxidation reaction with the wastewater (the optimal temperature range of the oxidation reaction is 270 to 290 ℃), and the oxidation reaction is continued along with the continuous supplement of the oxygen; the oxidation reaction is an exothermic reaction, the heat generated by the exothermic reaction further heats the two-phase flow mixture and the reaction product in the reactor 5, the temperature condition of the oxidation reaction is maintained by injecting high-temperature water vapor into the reactor 5 (influenced by the material concentration, when the material concentration is low, the oxidation reaction is exothermic, but the heat required by the oxidation reaction cannot be completely provided, so that insufficient heat needs to be supplemented), and the temperature of the outlet of the reactor 5 is maintained at 270 to 290; after the wastewater reacts in the reactor 5 for a sufficient time, the oxidized mixture of the wastewater and the non-condensable gas enters the feed and discharge heat exchanger 4 from the top of the reactor 5, and indirectly exchanges heat with the two-phase flow mixture to preheat the two-phase flow mixture; and (3) conveying the oxidized sewage and non-condensable gas mixture subjected to heat exchange to a process cooler 6, indirectly cooling the oxidized sewage and non-condensable gas mixture by using cooling water (40-80 ℃), and conveying the cooled oxidized sewage and non-condensable gas mixture to a separator 8.

Before entering the separator 8, the flow of the oxidized sewage and non-condensable gas mixture passing through the pressure reducing valve 7 is controlled to maintain the constant pressure at the outlet of the reactor 5, the oxidized sewage and non-condensable gas mixture is separated into a gas phase and a liquid phase in the separator 8, the gas phase is discharged from the top of the separator 8, and the liquid phase is conveyed to the homogenizing tank 9 from the bottom of the separator 8, so that the treatment of the PO/SM high-salt high-COD wastewater is completed.

The products of the oxidation reaction of the high-salt and high-COD wastewater and oxygen in the reactor 5 are substances such as malonic acid, carbon dioxide and the like, and the reaction formula is as follows:

HOCH ₂ -CH ₂ -CH ₂ OH+O ₂ →HOOHC-CH ₂ -CHOOH，

C ₆ H ₅ -C ₂ H ₄ -OH+10O ₂ →8CO ₂ +5H ₂ O。

drawings

FIG. 1: the structure schematic diagram of the device for treating the PO/SM high-salt and high-COD wastewater of the utility model is shown;

the names of the parts are: the system comprises a waste water storage tank 1, a low-pressure water supply pump 2, a high-pressure feed pump 3, a feed and discharge heat exchanger 4, a reactor 5, a process cooler 6, a pressure reducing valve 7, a separator 8 and a homogenizing tank 9. The waste water storage tank 1, the low-pressure water feed pump 2 and the high-pressure feed pump 3 can be connected by using a 20# steel conveying pipeline, and the pipe diameter is DN100; the material of a conveying pipeline connected among the high-pressure feed pump 3, the feed and discharge heat exchanger 4, the reactor 5, the process cooler 6 and the pressure reducing valve 7 is 316, and the pipe diameter is DN100; the material of a conveying pipeline connected among the pressure reducing valve 7, the separator 8 and the homogenizing tank 9 is 316L, and the pipe diameter is DN150;

the feeding and discharging heat exchanger 4 and the process cooler 6 are both double-pass tubular indirect heat exchangers (which are divided into a shell pass and a tube pass, for the feeding and discharging heat exchanger 4, a two-phase flow mixture from the high-pressure feeding pump 3 flows through the shell pass, a mixture of oxidized sewage and non-condensable gas from the reactor 5 flows through the tube pass, for the process cooler 6, a mixture of oxidized sewage and non-condensable gas from the feeding and discharging heat exchanger 4 flows through the shell pass, cooling water from the outside of the device flows through the tube pass), the pressure reducing valve 7 is an angle-shaped pressure reducing regulating valve, and the inside of the reactor 5 is provided with a 4-layer floating valve tower plate structure for improving the heat exchange area between water vapor and sewage. The separator 8 is a common pressure vessel and has no special structure inside.

Detailed Description

Example 1:

the specific process and control indexes of the device are as follows:

normal-temperature (20 ℃) PO/SM high-salt and high-COD wastewater (HPW, high-concentration water) generated by the PO/SM device is conveyed into a wastewater storage tank 1 through a pipeline and then conveyed into a high-pressure feeding pump 3 through a low-pressure water feeding pump 2 (the flow is 20 to 40t/h); the HPW is pressurized to 8-10MpaG by a high-pressure feeding pump 3, compressed air of 9-11MpaG is mixed at the outlet of the high-pressure feeding pump 3 (the volume ratio range of pumped liquid to the compressed air is 1-50-100), so that the HPW becomes a two-phase flow mixture of a gas phase and a liquid phase, the two-phase flow mixture enters a feeding and discharging heat exchanger 4 together, and then the temperature is raised to 170-210 ℃ from the original normal temperature through indirect heat exchange in the feeding and discharging heat exchanger 4; the HPW heated to 170-210 ℃ enters the reactor 5 from the bottom of the reactor 5, and simultaneously, the reactor 5 is also filled with externally supplied normal-temperature high-purity oxygen (with the purity of more than 99.96%) of 10MPaG and high-temperature water vapor (with the purity of 9-11MpaG and the temperature of 300-340 ℃) (the main function of the oxygen is to be used as an oxidant, COD (chemical oxygen demand) of the two-phase flow mixture of 160-200g/L is oxidized and reduced to about 64-80g/L in the reactor 5, and the high-temperature water vapor at the temperature of 300-340 ℃ has the function of providing the heat required by the device during initial starting and the oxidation reaction in the reactor 5 (the flow rate of the two-phase flow mixture is 2m/s, and the flow rates of the oxygen and the water vapor are 20-40m/s), and the reactor 5 adopts a direct contact type to provide heat.

Temperature remote transmission tables are arranged at the lower part, the middle part and the upper part of the reactor 5, the initial temperature of the HPW entering the reactor 5 is 170 to 210 ℃, and the temperature of the mixture of the oxidized sewage and the non-condensable gas exiting the reactor 5 is 270 to 290 ℃; in the reactor 5, the HPW is in contact with oxygen and steam to fully carry out an oxidation reaction (60 to 100 minutes), and the oxidized sewage and non-condensable gas mixture after the reaction flows out of the upper part of the reactor 5 and then enters the charging and discharging heat exchanger 4 again; in a feeding and discharging heat exchanger 4, carrying out first time of indirect heat exchange (20 to 40 minutes) on the oxidized sewage and non-condensable gas mixture after reaction and a two-phase flow mixture, and cooling (20 to 40 minutes and second time of indirect heat exchange) the oxidized sewage and non-condensable gas mixture (with the temperature of 170 to 210 ℃) flowing out of the bottom of the feeding and discharging heat exchanger 4 in a process cooler 6, wherein the oxidized sewage and non-condensable gas mixture is in solid, liquid and gas three-phase coexistence, the pressure is 7 to 9MpaG, the temperature is 40 to 80 ℃, and the COD is 64 to 80g/L; reducing the pressure of the oxidized sewage and non-condensable gas mixture by using a pressure reducing valve 7, wherein the pressure of the oxidized sewage and non-condensable gas mixture wastewater is reduced from 7 to 9MpaG to 0.6 to 0.8MpaG, and other indexes are unchanged; the mixture of the oxidized sewage and the non-condensable gas with reduced pressure enters a separator 8 (15 to 30 minutes), the gas phase is separated from the liquid phase, and the mixture of the oxidized sewage and the non-condensable gas containing the liquid phase enters a homogenizing tank 9 to wait for entering a biochemical system; the gas phase is discharged from the top of the separator 8.

Claims

1. The utility model provides a device that is used for high salt of PO/SM, high COD waste water treatment which characterized in that: the device consists of a waste water storage tank (1), a low-pressure water feeding pump (2), a high-pressure feeding pump (3), a feeding and discharging heat exchanger (4), a reactor (5), a process cooler (6), a pressure reducing valve (7), a separator (8) and a homogenizing pool (9), wherein all parts are connected through a conveying pipeline; the low-pressure feed pump (2) sends the high-salt and high-COD wastewater stored in the wastewater storage tank (1) to the high-pressure feed pump (3), and the high-pressure effluent is mixed with compressed air from an air compressor to form a two-phase flow mixture; the two-phase flow mixture is subjected to indirect heat exchange with the high-temperature discharge of the reactor (5) in the feed and discharge heat exchanger (4), so that the two-phase flow mixture is preheated; the preheated two-phase flow mixture enters the bottom of the reactor (5) and is subjected to oxidation reaction together with pure oxygen from the outside of the device; after the wastewater reacts in the reactor (5) for enough time, the mixture of the oxidized wastewater and the non-condensable gas enters the feeding and discharging heat exchanger (4) from the top of the reactor (5) to indirectly exchange heat with the two-phase flow mixture, and the two-phase flow mixture is preheated; the mixture of the oxidized sewage and the non-condensable gas after heat exchange is conveyed to a process cooler (6) and is indirectly cooled by cooling water, and the cooled mixture of the oxidized sewage and the non-condensable gas is conveyed to a separator (8); maintaining a constant pressure at the outlet of the reactor (5) by controlling the flow of the mixture of oxidized effluent and non-condensable gases through a pressure reducing valve (7); and separating gas phase and liquid phase from the oxidized sewage and non-condensable gas mixture in a separator (8), wherein the gas phase is discharged from the top of the separator (8), and the liquid phase is conveyed to a homogenizing pool (9) from the bottom of the separator (8), so that the treatment of the PO/SM high-salt high-COD wastewater is completed.

2. The apparatus of claim 1 for PO/SM high salt, high COD wastewater treatment, wherein: the feeding and discharging heat exchanger (4) and the process cooler (6) are both double-pass tube type indirect heat exchangers and are divided into a shell pass and a tube pass; for the feed-discharge heat exchanger (4), a two-phase flow mixture from a high-pressure feed pump (3) flows through the shell side, and an oxidized sewage and non-condensable gas mixture from a reactor (5) flows through the tube side; for the process cooler (6), the oxidized sewage and non-condensable gas mixture from the feed-discharge heat exchanger (4) flows through the shell side, and the cooling water from the outside of the device flows through the tube side.

3. The apparatus of claim 1 for PO/SM high salt, high COD wastewater treatment, wherein: the pressure reducing valve (7) is an angle-shaped pressure reducing regulating valve, and a 4-layer floating valve tower plate structure is arranged inside the reactor (5) and used for increasing the heat exchange area of water vapor and sewage.

4. The apparatus of claim 1 for PO/SM high salt, high COD wastewater treatment, wherein: direct contact type heat exchange is adopted in the reactor (5).