A water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water

Abstract

The utility model relates to the technical field of water treatment, and specifically to a water treatment system for synergistically removing total organic carbon from coal chemical biochemical tail water, comprising: an advanced oxidation system, a deep biochemical system, a primary reverse osmosis system, a secondary reverse osmosis system and a boiler resin exchange system which are arranged in sequence, wherein the front end of the boiler resin exchange system is also connected to a reverse osmosis system for treating raw water; the utility model scheme reduces the total organic carbon of coal chemical biochemical tail water through the above-mentioned synergistic systems, so that the final effluent can stably reach a total organic carbon of less than 0.5 mg / L, thereby solving the problem that the coal chemical biochemical tail water cannot meet the water requirements of high-temperature and high-pressure boilers with lower investment and treatment costs.

Description

Technical Field

[0001] The utility model relates to the technical field of water treatment, in particular to a water treatment system for collaboratively removing total organic carbon from coal chemical and biochemical tail water. Background Art

[0002] Coal chemical wastewater is generally divided into easily degradable coal chemical wastewater and difficult to degrade coal chemical wastewater. After biochemical treatment, its biochemical tail water is divided into difficult to degrade coal chemical biochemical tail water and degradable coal chemical biochemical tail water. Large-scale production of coal chemical industry requires a large amount of high-temperature and high-pressure steam. When high-temperature and high-pressure boiler water is gasified at high temperature, organic matter in the boiler water reacts with water to generate hydrogen. The accumulation of hydrogen leads to the risk of boiler explosion. Therefore, according to the water use requirements of high-temperature and high-pressure boilers (GB / T1576-2018 Industrial Boiler Water Quality), the total organic carbon (TOC) of water entering high-temperature and high-pressure boilers must be less than 0.5mg / L.

[0003] Raw water or tap water has low organic matter content, and the total organic carbon (TOC) of the effluent can be reduced to below 0.5mg / L by using the reverse osmosis treatment system equipped with the boiler. However, it is difficult for industrial biochemical tail water to meet the requirement of 0.5mg / L of total organic carbon (TOC) of the effluent. It can only be used at the low end, such as circulating water, greening, flushing toilets, and river water replenishment. The treatment of coal chemical biochemical tail water faces problems such as low resource utilization and waste of water resources.

[0004] At present, industrial biochemical tail water is treated separately to the total organic carbon (TOC) of 0.5mg / L. First, deep biochemical treatment is carried out to remove organic matter as much as possible, and then ozone deep oxidation, activated carbon adsorption, resin adsorption, nanofiltration, primary or secondary reverse osmosis treatment are carried out. After a series of fine and repeated treatments, it is possible to achieve a certain degree of success. Not only is the treatment process very long, but the investment and operation costs are also very high. In fact, due to the complex composition of coal chemical wastewater, its biochemical tail water composition is even more complex. Common activated carbon adsorption, resin adsorption, nanofiltration membrane and reverse osmosis membrane removal cannot treat coal chemical biochemical tail water to a total organic carbon (TOC) of less than 0.5mg / L, and cannot meet the water requirements of high-temperature and high-pressure boilers. Utility Model Content

[0005] The utility model aims to provide a water treatment system for removing total organic carbon from biochemical tail water, so as to solve the problem that the current coal chemical biochemical tail water cannot meet the water requirements of high-temperature and high-pressure boilers due to high total organic carbon.

[0006] In order to achieve the above-mentioned purpose, the utility model provides a water treatment system for coal chemical biochemical tail water to collaboratively remove total organic carbon. The coal chemical biochemical tail water is classified from the source according to the biodegradability B / C ratio (5-day biochemical oxygen demand / chemical oxygen demand). The degradable biochemical tail water with a B / C ratio greater than 0.3 directly enters the deep biochemical system. The difficult-to-degrade biochemical tail water with a B / C ratio less than 0.3 is subjected to advanced oxidation treatment to improve biodegradability. The B / C ratio is increased to above 0.3 before entering the deep biochemical system. Through the deep After treatment by the biochemical system, the total organic carbon (TOC) content of the effluent is stably controlled, and the effluent total organic carbon (TOC) is less than 25mg / L; the effluent of the deep biochemical system is then treated by the secondary reverse osmosis system to remove organic matter and salt in the water. The total organic carbon (TOC) of the other raw water is less than 10mg / L (generally the water quality is above Class III surface water). After treatment by the reverse osmosis system, the effluent is mixed with the secondary reverse osmosis effluent, and then treated by the boiler resin exchange system. The effluent total organic carbon (TOC) is less than 0.5mg / L. The coal chemical biochemical tailwater treatment system and the boiler feed water treatment system complement each other and realize the high-quality reuse requirements of the coal chemical biochemical tailwater.

[0007] According to the above ideas, the utility model provides a water treatment system for the synergistic removal of total organic carbon from coal chemical biochemical tail water, including an advanced oxidation system, a deep biochemical system, a primary reverse osmosis system, a secondary reverse osmosis system and a boiler resin exchange system arranged in sequence, and the front end of the boiler resin exchange system is also connected to a reverse osmosis system for treating raw water. The above system realizes the treatment of coal chemical biochemical tail water through the following steps to meet the requirements of high temperature and high pressure boiler water:

[0008] (1) The tail water of the coal chemical wastewater after biochemical treatment is divided into hard-to-degrade coal chemical biochemical tail water and degradable coal chemical biochemical tail water, and the hard-to-degrade coal chemical biochemical tail water is further treated by an advanced oxidation system;

[0009] (2) The effluent from the difficult-to-degrade coal chemical biochemical tail water treated by the advanced oxidation system and the degradable coal chemical biochemical tail water are mixed and sent into the deep biochemical system for treatment, and the total organic carbon (TOC) of the effluent is less than 25 mg / L, preferably 15-20 mg / L;

[0010] (3) mixing the effluent from step (2) and the secondary reverse osmosis concentrated phase water into a primary reverse osmosis system for treatment;

[0011] (4) the effluent from step (3) enters a secondary reverse osmosis system, and the effluent total organic carbon (TOC) is less than 2 mg / L, preferably 1.5-1.8 mg / L;

[0012] (5) The concentrated phase water of the secondary reverse osmosis system and the effluent of step (2) are mixed and sent to the primary reverse osmosis system for treatment;

[0013] (6) treating the raw water through a reverse osmosis system;

[0014] (7) Mixing the effluents from step (4) and step (6) and entering the boiler resin exchange system, wherein the total organic carbon (TOC) of the effluent is less than 0.5 mg / L, preferably 0.3-0.5 mg / L;

[0015] (8) the concentrated phase water of the primary reverse osmosis system of step (4) is sent to a desalination system for treatment;

[0016] (9) The effluent from step (7) enters the boiler feed water subsequent treatment system.

[0017] The B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the degradable coal chemical biochemical tail water is greater than 0.3, and the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the difficult-to-degrade coal chemical biochemical tail water is less than 0.3. The two types of biochemical tail water can be configured in any proportion; the total organic carbon (TOC) of the degradable coal chemical biochemical tail water is less than 30 mg / L, preferably 25-30 mg / L; the total organic carbon (TOC) of the difficult-to-degrade coal chemical biochemical tail water is less than 150 mg / L, preferably 80-120 mg / L, the advanced oxidation system is an ozone catalytic oxidation system or a hydrogen peroxide ozone combined catalytic oxidation system, preferably a hydrogen peroxide ozone combined catalytic oxidation system, and after the difficult-to-degrade coal chemical biochemical tail water is treated by the advanced oxidation system, the effluent B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio is greater than 0.3.

[0018] The deep biochemical system is an anoxic-aerobic-aerated biological filter (AO-BAF) system or an anoxic-aerobic-microfiltration membrane (AO-MBR) system.

[0019] The reverse osmosis membrane materials selected for the primary reverse osmosis system and the secondary reverse osmosis system are cellulose acetate, aromatic polyamide, chitosan membrane, polyphenylene reverse osmosis membrane or composite membranes made of the above materials.

[0020] The total organic carbon (TOC) of the raw water is less than 10 mg / L, and the mixing ratio of the raw water after the reverse osmosis system and the secondary reverse osmosis system is 0.5-2:1, preferably 0.8-1.2:1.

[0021] The boiler resin exchange system is a cation exchange column and anion exchange column system or a cation-anion mixed bed exchange column system.

[0022] The anoxic-aerobic-microfiltration membrane (AO-MBR) system has a residence time of 12-48 hours, preferably 24 hours; the anoxic-aerobic-aerated biological filter (AO-BAF) system has a residence time of 12-48 hours, preferably 24 hours.

[0023] The effluent of the anoxic-aerobic-aerated biological filter (AO-BAF) system is connected to the primary reverse osmosis system after microfiltration or ultrafiltration, while the effluent of the anoxic-aerobic-microfiltration membrane (AO-MBR) system is directly connected to the primary reverse osmosis system.

[0024] The utility model carries out advanced oxidation on the difficult-to-degrade coal chemical biochemical tail water, and then carries out deep biochemical treatment together with the degradable coal chemical biochemical tail water, and then carries out secondary continuous reverse osmosis; another raw water for boiler feed water is subjected to reverse osmosis treatment, and then mixed with the secondary continuous reverse osmosis effluent, and finally processed through a boiler resin exchange system, etc., and a series of steps are carried out, and the total organic carbon (TOC) of the effluent is less than 0.5 mg / L, thus realizing the innovation of the present technology.

[0025] The utility model coordinates and cooperates with an advanced oxidation system, a deep biochemical system, a primary reverse osmosis system, a secondary reverse osmosis system, a boiler resin exchange system, and a reverse osmosis system for treating raw water arranged at the front end of the boiler resin exchange system, stably controls the total organic carbon content from the source, controls the total organic carbon content through a two-stage continuous reverse osmosis system, and then mixes the effluent water with another raw water for boiler feed water through reverse osmosis treatment, and finally synergistically treats the effluent water to stably reach a total organic carbon (TOC) of less than 0.5 mg / L through the boiler resin exchange system. As a result, the coal chemical biochemical tail water can finally meet the water requirements of high-temperature and high-pressure boilers, avoiding the problem of water resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to the utility model;

[0027] Figure 2 This is a block diagram of the ozone catalytic oxidation system;

[0028] Figure 3 This is a block diagram of the hydrogen peroxide ozone combined catalytic system;

[0029] Figure 4 This is a block diagram of the anoxic-aerobic-aerated biological filter system;

[0030] Figure 5 Block diagram of anoxic-aerobic-microfiltration membrane system;

[0031] Figure 6 This is the block diagram of the raw water reverse osmosis system;

[0032] Figure 7 This is a block diagram of a primary reverse osmosis system and a secondary reverse osmosis system. DETAILED DESCRIPTION

[0033] The following is further described in detail through specific implementation methods:

[0034] Example:

[0035] like Figure 1-7 As shown, this embodiment provides a water treatment system for synergistically removing total organic carbon from coal chemical biochemical tail water, including an advanced oxidation system, a deep biochemical system, a primary reverse osmosis system, a secondary reverse osmosis system and a boiler resin exchange system arranged in sequence, and the front end of the boiler resin exchange system is also connected to a reverse osmosis system for treating raw water;

[0036] The advanced oxidation system is an ozone catalytic oxidation system, which is used to oxidize the biochemical tail water from the coal chemical industry that is difficult to degrade;

[0037] The boiler resin exchange system is a cation exchange column and anion exchange column system, and the mixed water enters the cation exchange column and the anion exchange column in sequence;

[0038] The deep biochemical system is an anoxic-aerobic-microfiltration membrane (AO-MBR) system, which is used to biochemically treat the effluent from the advanced oxidation system and the biodegradable coal chemical biochemical tail water, with a tail water retention time of 24 hours;

[0039] The primary reverse osmosis system is used to perform reverse osmosis treatment on the effluent from the deep biochemical system, and the generated concentrated phase water is sent to the desalination system;

[0040] The secondary reverse osmosis system is used to perform reverse osmosis treatment on the effluent of the primary reverse osmosis system, and the generated concentrated phase water is sent to the primary reverse osmosis system; the reverse osmosis membrane material selected for the primary reverse osmosis system and the secondary reverse osmosis system is cellulose acetate membrane.

[0041] Raw water reverse osmosis system, used to perform reverse osmosis treatment on raw water;

[0042] The boiler resin exchange system is used to perform ion exchange treatment on the effluent from the raw water reverse osmosis system and the effluent from the secondary reverse osmosis system.

[0043] The water treatment system of this embodiment performs the following steps to remove the total organic carbon in the coal chemical biochemical tail water:

[0044] (1) The tail water of coal chemical wastewater after biochemical treatment is divided into refractory coal chemical biochemical tail water and degradable coal chemical biochemical tail water. The refractory coal chemical biochemical tail water is further treated by an advanced oxidation system. The B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the degradable coal chemical biochemical tail water is 0.4, and the B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio of the refractory coal chemical biochemical tail water is 0.2. The configuration ratio of the two biochemical tail waters is 2:1; the total organic carbon (TOC) of the degradable coal chemical biochemical tail water is 28 mg / L; the total organic carbon (TOC) of the refractory coal chemical biochemical tail water is 120 mg / L. After the refractory coal chemical biochemical tail water is treated by the advanced oxidation system, the effluent B / C (5-day biochemical oxygen demand / chemical oxygen demand) ratio is 0.4.

[0045] (2) The effluent from the difficult-to-degrade coal chemical biochemical tail water treated by the advanced oxidation system and the degradable coal chemical biochemical tail water are mixed and sent into the deep biochemical system for treatment, and the total organic carbon (TOC) of the effluent is 20 mg / L;

[0046] (3) the effluent from step (2) is treated in a primary reverse osmosis system;

[0047] (4) The effluent from step (3) enters a secondary reverse osmosis system, and the total organic carbon (TOC) of the effluent is 1.8 mg / L;

[0048] (5) mixing the concentrated phase water of the secondary reverse osmosis system into the effluent of step (2);

[0049] (6) The raw water was treated by a reverse osmosis system, and the total organic carbon (TOC) of the raw water was 8 mg / L;

[0050] (7) Mix the effluents from step (4) and step (6) and enter the boiler resin exchange system at a mixing ratio of 1:1, and the total organic carbon (TOC) of the effluent is 0.45 mg / L;

[0051] (8) the concentrated phase water of the primary reverse osmosis system of step (4) is sent to a desalination system for treatment;

[0052] (9) The effluent from step (7) enters the boiler feed water subsequent treatment system.

[0053] Among them, the ozone catalytic oxidation system includes a first catalytic oxidation tower and a first tail water inlet pipeline and a first ozone inlet pipeline connected thereto, wherein the first tail water inlet pipeline includes an inlet pump and a buffer tank, and the first ozone inlet pipeline includes a vacuum adsorption oxygen generator, an ozone generator and an ozone and oxygen separation and recovery device.

[0054] The anoxic-aerobic-aerated biological filter system includes a sewage lifting pump, a buffer tank, anoxic tank, an aerobic tank, and an aerated biological filter which are arranged in sequence. Both the aerobic tank and the aerated biological filter are provided with aeration devices. A mixed liquid circulation pump and a sludge thickening device are also provided between the aerobic tank and the anoxic tank. In order to ensure the normal operation of the aerated biological pool, the aerated biological pool is provided with a filter backwashing device.

[0055] The anoxic-aerobic-microfiltration membrane system includes a sewage lifting pump, a buffer tank, anoxic tank, an aerobic tank and a microfiltration membrane system which are arranged in sequence. The aerobic tank is connected to an aeration device. A mixed liquid circulation pump and a sludge concentration device are arranged between the aerobic tank and the anoxic tank. The microfiltration membrane system is connected to a membrane cleaning and regeneration device.

[0056] The raw water reverse osmosis system includes a raw water lifting pump, a buffer tank, a raw water pressure pump, a quartz sand filter, an activated carbon filter, an antiscalant dosing system, a safety filter, a high-pressure pump, a reverse osmosis device and a pure water storage tank which are arranged in sequence.

[0057] The primary reverse osmosis system and the secondary reverse osmosis system include a lifting water pump, a water storage tank, a pressure pump, a multi-media filter, a dosing device, a booster pump, an ultrafiltration device, a backwash pump, an ultrafiltration water tank, an RO water feed pump, a dosing device, a primary safety filter, a primary RO high-pressure pump, a primary reverse osmosis device, a primary reverse osmosis effluent buffer tank, a secondary RO high-pressure pump, a secondary reverse osmosis device and a secondary reverse osmosis effluent storage tank which are arranged in sequence.

[0058] The boiler resin exchange system comprises a water inlet pump, a cation exchange column, an anion exchange column, a mixed bed exchange column and a resin regeneration system which are arranged in sequence.

[0059] Among the components of the above-mentioned system, those skilled in the art may also make replacements according to actual production conditions, for example, the ozone catalytic oxidation system of the advanced oxidation system may be replaced by a hydrogen peroxide ozone combined catalytic oxidation system; the hydrogen peroxide ozone combined catalytic oxidation system comprises a second catalytic oxidation tower and a second tail water inlet pipeline, a hydrogen peroxide inlet pipeline and a second ozone air inlet pipeline connected thereto, wherein the second tail water inlet pipeline comprises an inlet pump and a buffer tank, the second ozone air inlet pipeline comprises a vacuum adsorption oxygen generator, an ozone generator and an ozone and oxygen separation and recovery device, and the hydrogen peroxide inlet pipeline comprises a hydrogen peroxide storage tank and a hydrogen peroxide feed pump.

[0060] The anoxic-aerobic-aerated biological filter system of the deep biochemical system is replaced by an anoxic-aerobic-microfiltration membrane system. At this time, the corresponding primary reverse osmosis system and secondary reverse osmosis system include a lifting pump, a water storage tank, a water feed pump, a multi-media filter, a dosing device, a primary security filter, a primary RO high-pressure pump, a primary reverse osmosis device, a primary reverse osmosis effluent buffer tank, a secondary RO high-pressure pump, a secondary reverse osmosis device and a secondary reverse osmosis effluent storage tank. The secondary reverse osmosis concentrated water returns to the water storage tank.

[0061] The above is only an embodiment of the utility model, and the common knowledge such as the known specific technical schemes and / or characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the technical scheme of the utility model. In the utility model, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the utility model can be understood according to the specific circumstances. The scope of protection claimed in this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water, characterized by: It includes an advanced oxidation system, a deep biochemical system, a primary reverse osmosis system, a secondary reverse osmosis system and a boiler resin exchange system which are arranged in sequence. The front end of the boiler resin exchange system is also connected to a reverse osmosis system for treating raw water. in Advanced oxidation system, used to oxidize the biochemical tail water from coal chemical industry that is difficult to degrade; Deep biochemical system, used to biochemically treat the effluent from the advanced oxidation system and the biodegradable coal chemical industry tail water; The primary reverse osmosis system is used to perform reverse osmosis treatment on the effluent from the deep biochemical system, and the generated concentrated phase water is sent to the desalination system; The secondary reverse osmosis system is used to perform reverse osmosis treatment on the effluent from the primary reverse osmosis system, and the generated concentrated phase water is sent to the primary reverse osmosis system; Raw water reverse osmosis system, used to perform reverse osmosis treatment on raw water; The boiler resin exchange system is used to perform ion exchange treatment on the effluent from the raw water reverse osmosis system and the effluent from the secondary reverse osmosis system to obtain water with a total organic carbon content of less than 0.5 mg / L.

2. A water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to claim 1, characterized in that: The advanced oxidation system is an ozone catalytic oxidation system or a hydrogen peroxide ozone combined catalytic oxidation system.

3. A water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to claim 2, characterized in that: The ozone catalytic oxidation system comprises a first catalytic oxidation tower and a first tail water inlet pipeline and a first ozone air inlet pipeline connected thereto, wherein the first tail water inlet pipeline comprises an inlet pump and a buffer tank, and the first ozone air inlet pipeline comprises a vacuum adsorption oxygen generator, an ozone generator and an ozone and oxygen separation and recovery device; the hydrogen peroxide ozone combined catalytic oxidation system comprises a second catalytic oxidation tower and a second tail water inlet pipeline, a hydrogen peroxide inlet pipeline and a second ozone air inlet pipeline connected thereto, wherein the second tail water inlet pipeline comprises an inlet pump and a buffer tank, the second ozone air inlet pipeline comprises a vacuum adsorption oxygen generator, an ozone generator and an ozone and oxygen separation and recovery device, and the hydrogen peroxide inlet pipeline comprises a hydrogen peroxide storage tank and a hydrogen peroxide feed pump.

4. A water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to claim 1, characterized in that: The deep biochemical system is an anoxic-aerobic-aerated biological filter system or an anoxic-aerobic-microfiltration membrane system.

5. A water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to claim 4, characterized in that: The anoxic-aerobic-aerated biological filter system comprises a sewage lifting pump, a buffer tank, anoxic tank, an aerobic tank, and an aerated biological filter which are arranged in sequence. The aerobic tank and the aerated biological filter are provided with an aeration device. A mixed liquid circulation pump and a sludge concentrating device are provided between the aerobic tank and the anoxic tank. The aerated biological filter is also provided with a filter backwashing device.

6. A water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to claim 4, characterized in that: The anoxic-aerobic-microfiltration membrane system comprises a sewage lifting pump, a buffer tank, an anoxic tank, an aerobic tank and a microfiltration membrane system which are arranged in sequence. The aerobic tank is connected to an aeration device. A mixed liquid circulation pump and a sludge concentration device are arranged between the aerobic tank and the anoxic tank. The microfiltration membrane system is connected to a membrane cleaning and regeneration device.

7. The water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to claim 1 is characterized by: The raw water reverse osmosis system comprises a raw water lifting pump, a buffer tank, a raw water pressure pump, a quartz sand filter, an activated carbon filter, a scale inhibitor dosing system, a safety filter, a high-pressure pump, a reverse osmosis device and a pure water storage tank which are arranged in sequence.

8. The water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to claim 1 is characterized by: The boiler resin exchange system comprises a water inlet pump, a cation exchange column, an anion exchange column, a mixed bed exchange column and a resin regeneration system which are arranged in sequence.

9. A water treatment system for synergistically removing total organic carbon from coal chemical and biochemical tail water according to claim 1, characterized in that: The primary reverse osmosis system and the secondary reverse osmosis system include a lifting water pump, a water storage tank, a pressure pump, a multi-media filter, a dosing device, a booster pump, an ultrafiltration device, a backwash pump, an ultrafiltration water tank, an RO water supply pump, a dosing device, a primary safety filter, a primary RO high-pressure pump, a primary reverse osmosis device, a primary reverse osmosis effluent buffer tank, a secondary RO high-pressure pump, a secondary reverse osmosis device and a secondary reverse osmosis effluent storage tank, which are arranged in sequence.

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